Technical Manual 2025

Technical Manual 2025
Table of Contents
Services
Table of Contents
Materials and Process Engineering
Table of Contents
Seals for Rotary Applications
Table of Contents
Seals for Fluid Power Applications – Hydraulics
Table of Contents
Seals for Fluid Power Applications – Pneumatics
Table of Contents
Static Seals
Table of Contents
Special Sealing Products
Table of Contents
Hydraulic Accumulators
Table of Contents
Boots & Bellows
Table of Contents
Diaphragms
Table of Contents
Stuffing Box Packings
Table of Contents
Index

The information contained in this Technical Manual is based on decades of research into the development and manufacture of seals by the Freudenberg Group and re- flects the current state of knowledge. This Technical Manual and the information con- tained therein apply exclusively to Freuden- berg brand products. Products of the Dich- tomatik brand have not been taken into account in preparing this manual. The sealing effect of many products is not produced solely by the component itself, however. Depending on the specific appli- cation, it depends to a large extent on the other parameters, such as installation and mating point, pressurization, operating temperature, the media to be sealed, lubrication and possible accumulation of dirt from the outside. These and other factors can have a marked influence on the function of the seals when they are put to practical use. With this in mind, it is not possible to make general statements about how Freudenberg products function. The infor mation in this manual is intended only as a general, non-binding guide and is not valid for every application. It is rec- ommended that specific applications be discussed with the experts at Freuden- berg Sealing Technologies. In the case of particularly high and special loads, such as those caused by aggressive media, the seal should be selected in close cooperation and after consultation. In this context, tests to verify the functional reliability are usually indispensable. In the course of optimizing its products, Freudenberg Sealing Technologies re- serves the right to change the product range, production sites, products and their manufacturing processes as well as the information in this manual without prior notice. All previous publications become invalid with the publication of this edition. Reproduction in any form requires the express permission of Freudenberg FST GmbH, 69465 Weinheim, Germany. © Freudenberg FST GmbH All rights reserved. Registered trademarks of Simmerring®, Merkel®, Seventomatic®, Simriz®, Quantum® and Freudenberg Xpress® are globally protected, further registrations are possible. AdBlue®: AdBlue® is a registered trademark of VDA. Bonderite® / P3®: Bonderite® and P3® are registered trademarks of Henkel. The trademarks are identified on the basis of the information provided by the respec- tive rights holder and in accordance with that information. The use of the trade- marks is for informational purposes only and shows or explains the requirements or technical effects described in the text. Un- der no circumstances does the reference to the trademarks imply any business rela- tionship or other connection or endorse- ment by the respective rights holder of the trademarks. We do not accept any respon- sibility for the accuracy of the trademark protection information in different regions. The user-friendliness of this technical manual has been improved for you as a reader by integrating cross-references to other chapters and including important notes and links to external media, thus ensuring a holistic view of sealing tech- nology. Play-circle  Link to video Map-marker-edit Map-Marker-Exclamation Important Note Valuable information

TABLE OF CONTENTS Table of Contents 1. INTRODUCTION & SERVICES 2. MATERIALS AND PROCESS ENGINEERING 3. SEALS FOR ROTARY APPLICATIONS 4. SEALS FOR FLUID POWER APPLICATIONS – HYDRAULICS 5. SEALS FOR FLUID POWER APPLICATIONS – PNEUMATICS 6. STATIC SEALS 7. SPECIAL SEALING PRODUCTS 8. HYDRAULIC ACCUMULATORS 9. BOOTS & BELLOWS 10. DIAPHRAGMS 11. STUFFING BOX PACKINGS 12. INDEX 7 29 223 415 535 585 645 709 739 759 811 863 & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 1 X E D N I

Company COMPANY The Freudenberg Group was founded in 1849 and is still family-owned, making it independent, long-term oriented and responsible in its actions. Today, Freudenberg is a broadly diversified global Group. While Freudenberg & Co. Kommanditgesellschaft represents the strategic management company, Freuden- berg SE as the operational management company reflects the global nature of the Freudenberg Group. Freudenberg is divided into Business Groups that operate in a wide range of in- dustries. From Vileda® brand household products to technically complex sealing solutions, the company is always regarded as an innovation and technology leader. The Group’s strong segmentation has a single objective: to be close to the cus- tomer and to meet the demands made on a market expert. Its many research and development facilities ensure the company’s long-term success and enable a rapid response to market and customer- specific changes. Freudenberg Sealing Technologies (here- inafter also abbreviated FST) is the larg- est Business Group in the Freudenberg Group and forms part of the Seals and Vibration Control Technology Division. It is a supplier, as well as a development and service partner to customers in a wide range of market segments, the automo- tive industry, civil aviation, mechanical engineering and shipbuilding, the food and pharmaceutical industries and the agricultural and construction machinery industries, for example. Freudenberg website Freudenberg Sealing Technologies website 2

Company trial standards. The two-brand strategy is part of the comprehensive service port- folio and guarantees a full range of seals and product-related services. The unique range of services in the field of sealing technology sets standards for quality, functionality and cost-effective- ness in general industry. With its compre- hensive product range and broad range of services (→ chapter “Services”, page 7), Freudenberg Sealing Technologies offers a service package that is unique in the market – for virtually any application. FST puts its leading technological expertise to profitable use for its customers: Their complete systems are analyzed and the individual components are optimally matched to each other. In this way, they receive exactly the solution that best meets their needs – economically and reliably. Strengthened by time- and cost-saving single sourcing, customers will find their ideal partner for all sealing applications in Freudenberg Sealing Technologies, even for more complex systems. For decades, FST’s unique material exper- tise is a key success factor for the out- standing performance and continuous technological edge of its products. This is reflected in well-known product groups such as Simmerrings, fluid technology products, hydraulic accumulators, O-rings and liquid silicone products that form the world’s largest product range for all appli- cations in general industry. Since the 1980ies, Freudenberg Sealing Technologies is strategically expanding its portfolio to embrace the growing demands of e-mobility and green energy. The company is leveraging its extensive expertise in sealing solutions to support the development of electric vehicles (EVs) and sustainable energy systems. By focusing on innovative materials and advanced technologies, Freudenberg Sealing Technologies is enhancing the performance and reliability of EV compo- nents, such as battery systems and elec- tric drivetrains. In addition, the company is developing specialized sealing solu- tions for renewable energy applications, including wind turbines, solar panels, and hydrogen fuel cells. These solutions are designed to withstand harsh environ- mental conditions and ensure the longev- ity and efficiency of green energy systems. By driving innovation in this field, Freudenberg Sealing Technologies is contributing to the transition towards a more sustainable energy landscape, helping to reduce greenhouse gas emissions and promote environmental protection. Starting with the Simmerring® developed at Freudenberg in 1932, FST today has a broad, consistently customer-oriented product portfolio of sealing technology ranging from standard parts and custom- ized individual solutions to complete sealing packages. Together with its part- ners NOK Corporation, Japan, Freuden- berg-NOK, India, and NOK-Freudenberg Group, China, Freudenberg Sealing Tech- nologies forms a global network with the objective of offering products of the same high quality worldwide. The FST portfolio is rounded off by Dichtomatik brand products that reliably meet indus- & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 3 X E D N I

As part of the Freudenberg Group, Freudenberg Sealing Technologies draws on in-depth in-house research, and ex- pertise in development and production, to continually extend its technological lead through innovative solutions – for the benefit and in the service of custom- ers worldwide with their local market re- quirements. The extensive sales network provides reliable local support to its more than 100,000 customers in all industrial markets on all continents. THE FREUDENBERG SEALING TECHNOLOGIES RANGE OF SERVICES AT A GLANCE y World’s largest product range in sealing technology Integrated solutions from a single source y Permanent innovations Technological edge to give custom- ers a competitive advantage, thanks to specially developed products and materials y Unique materials expertise and high-quality standards Leading know-how for reliable and economical applications y Wide range of integrated services Partnership-based support from development, e.g. with the aid of FEM designs or tests on in-house test benches, through to long-term product use y Think global, act local Global expertise with knowledge of the local market requirements Company 4

Sustainability CO2 30% reduction in tons of CO2 / per million euros of revenue by 2025 Sustainability at Freudenberg & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A Freudenberg’s approach includes electri- fying its energy supply and minimizing CO2 emissions in manufacturing process- es. In addition, FST is dedicated to sustain- able production and business practices. The company emphasizes resource effi- ciency, focusing on reducing energy and material consumption. Its sustainability strategy also involves developing prod- ucts that help customers operate more efficiently and sustainably. S W O L L E B & S T O O B Sustainability at Freudenberg Sealing Technologies S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 5 X E D N I SUSTAINABILITY The sustainability of products and pro- cesses has always been part of Freuden- berg’s lived responsibility. In 2016, the Freudenberg Group developed a world- wide sustainability strategy that was handed over to all Business Groups, in- cluding Freudenberg Sealing Technologies, as a framework in 2017. In addition, sustainability was made a systematic component of the strategy process. Freudenberg Sealing Technologies is deeply committed to sustainability, with a clear focus on reducing its environmental impact. The company has set ambitious goals to cut its relative CO2 emissions by 30% from 2020 to 2025. By 2030, it aims to use exclusively renewable electricity sources. This commitment is part of a broader strategy to achieve carbon neu- trality through energy efficiency, waste reduction, and the optimization of mate- rials and technologies.

Initial projects and measures have shown that even small changes have a major im- pact on achieving climate targets. 100% green electricity by 2030 regions such as India, for example. The picture is also not uniform when it comes to materials. Some can be recycled, others such as elastomers (rubber) cannot. The three most important fields of action for all Business Groups are: Energy Effi- ciency, CO2 Emissions and Waste. Group- wide key performance indicators have been introduced for these areas, which have since created transparency on im- provements in these areas and help drive sustainability at Freudenberg. The five topics of materials, waste, energy, emissions and water are of the greatest rel- evance to the Group as a whole, although not all topics have the same significance for all Business Groups. Water, for exam- ple, is hardly used by some Business Groups, while it plays a major role in others, when production is located in water- scarce carbon neutrality by 2045 Sustainability 6

S E R V C E S I 7 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS S e r v i c e s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

Table of contents TABLE OF CONTENTS 1. DESIGN AND ENGINEERING 2. COATING 3. LUBE & SEAL 4. PRODUCT MODIFICATION 5. INSTALLATION AND DEINSTALLATION AIDS 6. PRODUCT MARKING 7. DAMAGE ANALYSIS 8. TEST BENCHES 9. LABORATORY TESTS 10. TRAINING 11. LC FREUDENBERG XPRESS® CUSTOMIZED SOLUTIONS 12. ONLINE TOOLS 8 10 11 12 13 14 15 16 17 18 19 20 24

SERVICES Services Expertise in all process areas, from re- search and development, materials and manufacturing to customer-oriented sales: this is the guarantee for our unique know-how and a product range of the highest quality. Conveying this knowl- edge directly and transparently to custom- ers is the goal of the services provided by Freudenberg Sealing Technologies (here- inafter also abbreviated FST). This Technical Manual presents a selection of current service points, whereby the focus is on services with a technical back- ground. For example, it is possible to adapt prod- ucts to your individual requirements by making modifications or applying coatings or markings. As a special service, FST has a fully comprehensive damage analysis department and one of the most modern accredited test laboratories. Expanding this knowledge and imparting it to you is possible in a joint dialog through the FST Academy. The wide range of services Freudenberg Sealing Technologies offers is rounded off by a variety of online services. Here, a wide range of selection options are avail- able to you via selectors or configurators, thus enabling you to make an easy and uncomplicated initial choice of the sealing solution. You can then order the prod ucts yourself in just a few steps via the product catalog and the EASY online ordering platform. Please visit the FST homepage for a complete overview of the services avail- able. FST Services & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 9 X E D N I

Services – Design and Engineering DESIGN AND ENGINEERING ENGINEERS MAINTENANCE PURCHASING/QM Questioning complex issues and understanding interrelationships is reflected in Freudenberg Seal- ing Technologies’ research and development centers worldwide, and it is hardly by chance that the word “innovation” is in the Freudenberg logo. FST lives this directly with its customers like only few other companies do. The network of highly qualified sealing technology employees – from product developers to application engineers – is quite unique. Specialists on individual segments or at the product level are available to customers worldwide. A closed value chain is the guarantee for targeted and precise support. From the developer of the compound formulation to the product developer, Freudenberg Sealing Technologies has all the ca- pabilities of efficient engineering. This bundled know-how, supplemented by subse- quent services such as various online tools or in- ternal testing facilities, enables holistic support for development projects. Here, FST grows together with its customers through the challenges of sealing technology. Would you like to learn more about Freudenberg Sealing Technologies’ products and services? Then get in touch with the person you normally deal with or use the contact options on fst.com. Design and Engineering VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y Highly qualified contacts y y Product- and/or application-specific y y Available worldwide y Also personally on site 10

Services – Coating & N O I T C U D O R T N I S E C I V R E S COATING D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A In addition to reducing friction, colorable bonded coatings make it easy to visually distinguish be- tween similar or identical seal dimensions. This drastically reduces the risk of confusion during installation. To meet the ever-increasing importance of the e-mobility sector, FST oﬀers the electrically con- ductive coating “EMI Shielding.” For further information, see also → chapter “Static Seals – 9. Modiﬁcations” on page 620. Excerpt of coating types Play-circle  Coating ENGINEERS MAINTENANCE PURCHASING/QM In addition to a wide range of products, Freuden- berg Sealing Technologies oﬀers its customers many diﬀerent options for environmentally friendly and standard-compliant high-performance coat- ings. Here, too, consistently high quality is ensured by relying on standardized processes and modern production. Freudenberg Sealing Technologies already applies a wide variety of coatings to well over 350 million parts a year. A coating can not only make assembly easier and thus increase the service life, but also optimize lubrication properties. A wide variety of coating options are available for this purpose. Coatings are also an eﬀective aid for stick-slip-free behavior and lower breakaway torques. S C I L U A R D Y H S C I T A M U E N P R E W O P D U L F I R E W O P D U L F I – S N O T A C I I L P P A – S N O T A C I I L P P A S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y Optimization of lubricating properties y y Stick-slip-free y y Lower breakaway torques y For automated assembly y Silicone and paint wetting interference-free y Non-stick eﬀect y EMI shielding y Technical cleanliness y Increase/guarantee of process reliability S M G A R H P A D I X O B G N I F F U T S I S G N K C A P X E D N I 11 11

Services – Lube & Seal LUBE & SEAL ENGINEERS MAINTENANCE PURCHASING/QM Lube & Seal: two worlds under one roof Sealing specialist meets lubricant expert – Simmer- ring® meets lubricant: the idea of harmonizing these two worlds and their chemical formulations is quite obvious. After all, it is only by taking a holistic view of the tribological sealing system – in particular the interaction between the sealing element and the lubricant – that it is possible to develop long-lasting and reliable sealing systems in drive technology. With Lube & Seal, the sealing specialist Freuden- berg Sealing Technologies and the lubricant expert Klüber Lubrication have combined their respective specific know-how to form comprehensive 12 Freudenberg technology expertise. Only Freuden- berg Sealing Technologies offers this comprehen- sive and unique service for optimizing sealing systems. Lube & Seal VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y Cost savings due to up to 25% longer functional y y y Safeguarding of warranty statements to the and service life end customer y Increased customer satisfaction through re- duced failure rates y Competitive advantages through a “Lube & Seal certified” sealing system

Services – Product Modiﬁcation & N O I T C U D O R T N I S E C I V R E S PRODUCT MODIFICATION D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A A compilation of the most common options, such as mechanical reworking or optimization of the spring contact forces for Simmerring® rotary shaft seals, has been compiled online for you. Please use the QR code provided for this purpose. For further information, see also → chapter “Seals for rotary applications – 9. Modiﬁed catalog goods” on page 333. FST Sales Sheet Modiﬁed Catalog Program ENGINEERS MAINTENANCE PURCHASING/QM A wide range of modiﬁcation options to meet individual product requirements With a wide range of dimensions, designs and ma- terials, the Freudenberg Sealing Technologies cat- alog program oﬀers a broad spectrum of sealing solutions. Nevertheless, speciﬁc operating condi- tions may require a seal optimized for the applica- tion. Adequate adaptation due to changing environ- mental parameters or the extension of service li- fecycles is crucial for many customers and can thus be guaranteed. For this purpose, it is possible in some product groups to optimize the current products from the extensive catalog range by making modiﬁcations. S C I L U A R D Y H S C I T A M U E N P R E W O P D U L F I R E W O P D U L F I – S N O T A C I I L P P A – S N O T A C I I L P P A S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y Extension of the service life y y Economically attractive y y Extension of the tool life y Optimization of functional reliability y Reduction of maintenance cycles S M G A R H P A D I X O B G N I F F U T S I S G N K C A P X E D N I 13

Services – Installation and Deinstallation Aids INSTALLATION AND DEINSTALLATION AIDS ENGINEERS MAINTENANCE PURCHASING/QM Tools for simple, fast and reliable installation and deinstallation of seals As diverse as the requirements for seals are, their installation is often just as complex. Whether it’s automatic assembly, directional or non-rotational, small or large, through to stiffness and deformabil- ity, everything plays a role. Special knowledge and tools are often needed. Freudenberg Sealing Technologies supports you with these challenges in a variety of ways – from arranging a personal contact on site to descriptive videos or the selection of one of the many prod- uct-specific aids and tools. 14 Play-circle  FST installation instructions VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE and humans y Vorteil 1 y Proper installation and deinstallation y y Avoidance of damage to the device, machine y y Warranty claims and image maintenance y Coordinated tools y Cost reduction

PRODUCT MARKING Services – Product Marking ENGINEERS MAINTENANCE PURCHASING/QM Clear marking ensures easy product identification and process reliability Freudenberg Sealing Technologies has always placed great importance on providing its custom- ers with comprehensive product information. From the manufacturing or batch number to the best-before date. This transparency is part of Freudenberg Sealing Technologies’ self-image of process reliability and quality assurance. In order to respond to your requirements even more specifically, labeling systems are offered for individualizing products. In order to ensure safety, optimization, high-level automation and quality control, markings are becoming more and more important and are a focus for customers. Other possible markings are: y Color markings to prevent mix-ups and support identification and traceability y Engravings that give seals individual branding and support identification and traceability y Printing provides additional labeling and facil- itates identification and traceability FST Product Marking VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y Branding according to customer requirements y y Traceability y y Simple and customer-specific identification y Reduction of mix-ups & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 15 X E D N I

Services – Damage Analysis DAMAGE ANALYSIS relevant application parameters. Product-specific questionnaires from Freudenberg Sealing Technol- ogies accelerate and simplify the analysis process. In conjunction with uncleaned failure samples or lubricant samples, they serve as a basis for further measures. At the beginning of damage analysis, the focus is usually on a visual inspection. Depending on the damage pattern, this is compared or verified by performing more in-depth analytical examina- tions. As a result, FST provides its customers with a documentation and evaluation of the findings including photos, followed by an action recom- mendation or remedial measures. Contact FST VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y Modern testing equipment y y Product and application specific know-how y y Access to in-depth expertise, such as material or product development y Experienced, highly qualified experts y Global network with local contacts ENGINEERS MAINTENANCE PURCHASING/QM Expert support reduces downtime and costs When elastomer seals fail, this usually leads to un- pleasant side effects such as downtime costs, complaints, or damage to reputation. However, clear traces can often be found on the seals that allow conclusions to be drawn about the damage mechanism. With the aid of state-of-the-art testing methods and equipment, Freudenberg Sealing Technologies is able to clearly analyze and isolate cases of dam- age. Often there is not just one cause of leakage. In many cases, it is only the interaction of a number of factors that leads to the damage pattern in question. For this reason, it is absolutely crucial for the damage analysis to have the user provide all 16

TEST BENCHES Services – Test Benches ENGINEERS MAINTENANCE PURCHASING/QM Development costs, time, process reliability and high-quality standards – all play an essential role in new or further development. Freudenberg Sealing Technologies continuously invests in new technologies to map the latest test methods. Always with the goal of avoiding cost-intensive trial runs and field tests. By working closely with the customer, FST is the only seal manufacturer to offer this added value across the entire product spectrum of sealing technology and its segments. Test Benches BENEFITS AT A GLANCE y Sealing tests under real conditions y Low development costs and fast development results y Optimized sealing concept (seal, shaft/rod, lubricant, application parameters) y Extended service life of all components y Verification of the service life requirement y Testing of your new and further develop- ments, prototypes & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 17 17 X E D N I

Services – Laboratory Tests LABORATORY TESTS Due to the direct proximity of material develop- ment, production, simulation and failure analysis, Freudenberg Sealing Technologies is able to take a comprehensive and globally unique approach that no other test laboratory can offer you. Over 170 years of experience, a continuously expand- ing database and a highly motivated team of ex- perts with the most modern testing facilities are waiting for you. Together with you, we will find the right tests and test parameters to solve your problem. Contact FST Laboratory Tests BENEFITS AT A GLANCE y Recognized laboratory with external quality y Vorteil 1 assurance through accreditation according to y DIN EN ISO/IEC 17025:2018 y y Material testing, materials and process know- how from a single source y Active participation in the design and estab- lishment of new testing methods y Individual, personal support, no matter whether it’s a standard test, a development-related question or analysis of damage ENGINEERS MAINTENANCE PURCHASING/QM What goes for the seal, goes for the test From conventional international standard tests to the most specialized elastomeric special tests, Freudenberg Sealing Technologies offers you a self-sufficient, certified and accredited test labo- ratory – with well over 200 tests from all relevant areas of rubber technology and their specific fea- tures. FST has adaptable test benches for specifications or specific questions that arise during develop- ment. This ensures that your general conditions are reproduced optimally and that reliable data is generated that you can build on. 18

TRAINING Services – Training ENGINEERS MAINTENANCE PURCHASING/QM Learning together – successful together With its wide range of online and classroom training courses, the FST Academy not only ensures that FST employees continue to develop their skills. It also offers a customized training program for custom- ers, suppliers and interested parties. Would you like to gain basic knowledge or deepen your un- derstanding of materials, design, and how seals function in various applications? Whether you are a beginner or a budding expert, you will find the right seminar here – tailored to your requirements and role. Self-paced online learning with the help of webinars as well as practice-oriented classroom training are systematically sequenced for an optimal learning process in theory and practice. Besides basic semi- nars, the range is rounded off by thematic master seminars and expert forums on trend-setting technologies and innovations. Discover the current training program of the FST Academy. Simply register for the training portal and sign up for your desired seminar. Freudenberg Sealing Technologies experts also regularly visit partners and customers. At so-called TechDays, they impart product knowledge on site and help solve problems. FST Academy VORTEILE IM ÜBERBLICK BENEFITS AT A GLANCE y Vorteil 1 y First-hand expertise y y Independent online learning y y Virtual training y Special seminars y Expert forums y Also on site & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 19 X E D N I

Services – LC Freudenberg Xpress® Customized Solutions LC FREUDENBERG XPRESS® CUSTOMIZED SOLUTIONS As a result, Freudenberg Xpress® develops its port- folio beyond CNC machined seal and part services by providing complementary CNC semi-finished products, tools, as well as CNC software and retrofit services. The service landscape is further comple- mented by the LC’s customized solutions service which supports its customers via highly custom- ized rubber-molded and rubber-metal parts. MACHINED SEALS Our state-of-the-art CNC production capabilities make the machining of original designs possible. A drawing, a sample or simply a discussion with our experts is usually all that is needed to develop your customized seal. In terms of quality, we offer original Freudenberg materials as well as industrial standard materials – manufactured and delivered in the shortest time frame. ENGINEERS MAINTENANCE PURCHASING/QM Freudenberg Xpress® becomes Lead Center Freudenberg Xpress® Customized Solutions Traditionally, the Lead Center (LC) Freudenberg Xpress® with its ad hoc CNC services is known for cus- tomer-specific sealing solutions in original Freuden- berg quality. Due to its global footprint and proxim- ity to its customers speed has always been essential. With the acquisition of the Trygonal Group in 2024, Freudenberg Xpress® further expanded its service capabilities becoming the first Industry Service Lead Center within Freudenberg Sealing Technologies. Freudenberg Xpress® Customized Solutions MACHINED SEALS & PARTS y MR O – Maintenance, Repair, and Overhaul y Prototyping y High-Precision y Small Series y Splicing & Welding CUSTOMIZED SOLUTIONS y Rubber-molded Parts y Rubber-metal Parts SEALING UTILITIES y CNC Billets (Components) y CNC Software & Machine Retrofit y CNC Tools Freudenberg Material Competence Compounds Freudenberg Sealing Competence Product Designs 20

Services – LC Freudenberg Xpress® Customized Solutions MRO – Maintenance, Repair, and Overhaul In case of urgent de- mands, we produce and deliver your parts within 24 hours – in original quality and design. The base for that is our global network and the resulting proximity to customers around the world. Prototyping We see the relationship to our customers as a part- nership. That is why we support them to validate their own sealing needs and come up with quick prototypes in original ma- terial quality. High-Precision Our innovative manufac- turing possibilities enable the smallest tolerance bands, whenever other production processes are no longer suitable. Small Series With our small series service, we provide our customers the most cost- efficient sealing and plastic part solutions. A time- consuming and costly tooling production is not necessary. Splicing & Welding With our splicing and welding technology, there are no limits in terms of seal size. Outstanding technical features are achieved throughout the whole seal. SEGMENTS AT A GLANCE y Distribution y Semiconductor y Hydropower y Oil & Gas y Food & Beverage y Pharmaceutical y Chemical y Other Energy & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 21 X E D N I

Services – LC Freudenberg Xpress® Customized Solutions CUSTOMIZED SOLUTIONS The customized solutions service supports our customers beyond the traditional boundaries of CNC machined seals and parts. It adds rubber-met- al parts, foam products as well as rubber parts or seals in different materials. Rubber Parts Whether your application requires a very large seal, extremely low tolerance bands, or customer-spe- cific solutions in smaller lot sizes – starting from lot-size 1 – our rubber part service is the solution. With the help of a variety of production tech- nologies, we can process and offer anything from industrial standard rubber to materials withstand- ing extreme conditions – in customer-specific dimensions. We can react in the shortest time to any customer-specific seal demand. Rubber-Metal Parts Being able to machine and process any kind of metal in-house, we can offer any kind of rubber- metal part. Starting from rather simple seals requir- ing a metal carrier to sup- port the product in the installation space up to highly-complex rubber-metal combinations re- quiring the bonding of highly demanding metal, thermoplastic, and/or elastomeric compounds. Our vertical integration and broad production portfolio pushes the boundaries of what is possi- ble even further. Foamed Products Whether it is a light yet ultra- stable special foam, a casting component with excellent mechanical properties, or a particularly tough integral foam, we can develop the right solution for you with our polyurethane foam product service. SEALING UTILITIES We support our customers not only with finished sealing products, but also with various products and services in the area of CNC production. This includes semi-finished products, CNC software, machine retrofit or CNC tools. CNC Billets (Components) We produce semi-finished products made for your own CNC production in sizes up to 2.1 metres in over 50 different materi- als. With more than 600 dimensions per material as well as industry-specific certificates (e.g. FDA, 3-A Sanitary Standards or EU (Reg.) 1935/2004), our extensive CNC semi- finished product portfolio provides the right solution for nearly every appli- cation. If specific requirements are needed, we also have the possibilities to develop a customer- specific compound for your individual application. CNC Software & Machine Retrofit We offer state-of-the-art CNC machines specifically tailored to your individual needs. During the respec- tive retrofit service, our experts offer extensive on-site consultation. Whether you need high automation, a high diam- eter range, or the most cost-efficient production equipment – we have the right solution. 22

Services – LC Freudenberg Xpress® Customized Solutions CNC Tools We stock indexable inserts, carbide knives, blades, holders and VD I holders from all well-known man- ufacturers made from the best These high-quality products are tailored to your individual machine system. steels. WORLDWIDE NETWORK A global network of local manufacturing partners and own production sites enables proximity to our customers. Expert advice on site and an extensive local service portfolio make us the right partner. & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Discover the Find out more in Explore the website! the brochure! production in the virtual tour! S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B FST Locations Partner locations S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 23 X E D N I

Online tools as a digital aid Freudenberg Sealing Technologies offers a wide range of online tools to make your daily work in the sealing business easier. Whether you use the product catalog and ordering platform to order your new seals or the FST configurators to find the right seal first, the online tools make it a breeze. Services – Online Tools ONLINE TOOLS ENGINEERS MAINTENANCE PURCHASING/QM PRODUCT CATALOG The FST product catalog provides an overview of the portfolio D o you need a Simmerring®, an O-ring or another seal? Whether you are looking for a Freudenberg premium seal or a Dichtomatik seal that meets common industry standards, you will find the right seal here. Explore the possibilities of the product catalog or contact the person you normally deal with if you are looking for an individual sealing solution. ORDERING PLATFORM EASY Order gaskets in the blink of an eye On the EASY ordering platform, you can quickly and easily find and order the seals you need and receive your specific prices and availability in real time. EASY gives you access to a uniquely large portfolio of over 130,000 products from the Freudenberg and Dichtomatik brands. With the EASY Business Connector, FST provides a powerful interface to which all common enterprise resource planning systems can be connected. EBC is thus a real alternative to EDI. 24 24

Services – Online Tools SIMMERRING® SELECTOR Are you looking for a Simmerring® suited for your field of application? With the help of the Simmerring® selector, you can quickly and easily find the right Simmerring® for your application by entering specific application parameters in just a few steps. O-RING CONFIGURATOR Are you looking for an O-ring and the correspond- ing installation space? FST’s innovative, web-based O-ring configurator sets improved standards as an auxiliary application for O-ring selection. The goal of this online tool is to select an optimal combination of O-ring and in- stallation space to ensure a reliable seal. Unlike other O-ring configuration programs, the calcula- tion analyses and target value recommendations are based on the current ISO 3601 and other inter- national O-ring standards. HYDRAULIC SELECTOR Are you in need for sealing solutions of your hy- draulic cylinder? Find the right seal for new designs or replacement seals in just a few clicks! The online application offers you the right sealing solution for your tech- nical requirements and installation space. The selector is connected to our EASY ordering platform to enable quick ordering. & N O I T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 25 X E D N I

Services – Online Tools ACCUMULATOR SELECTOR Our innovative Accumulator Selector simplifies the process of finding the right recommendations for an accumulator. With the selector, you can optimize your workflow and receive tailored solu- tions for your specific requirements. CHEMICAL RESISTANCE GUIDE Get exclusive access to the results of decades of testing and experience. The Chemical Resistance Guide shows you the appropriate sealing materi- als for the common process media used in gener- al industry and process industries, such as acids and sulfates, and helps you optimize your process- es and maximize seal life in the field. CIP/SIP GUIDE Determine the right cleaning agents for your pro- cess based on the Freudenberg materials you use. Or vice versa: find the right seal materials for your cleaning process. 26

CAD DOWNLOADS Use the two- and three-dimensional CAD geome- tries and model drawing sketches of tens of thou- sands of sealing components. These are available to you in a variety of ﬁle formats. The CAD service from Freudenberg Sealing Technologies makes it easier for you to design your components. Why com- plicate things when they can be so simple? 3D ANIMATIONS Discover the innovative sealing solutions for appli- cations in various market segments with the 3D an- imations from Freudenberg Sealing Technologies. Services – Online Tools & N O I T C U D O R T N I S E C I V R E S D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A S C I L U A R D Y H S C I T A M U E N P R E W O P D U L F I R E W O P D U L F I – S N O T A C I I L P P A – S N O T A C I I L P P A S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P X E D N I 27

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I M A T E R A L S A N D P R O C E S S E N G N E E R N G I I 2 9 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS M a t e r i a l s a n d p r o c e s s e n g n e e r i n g i INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

Materials and Process Engineering TABLE OF CONTENTS 1. HISTORY INTRODUCTION TO THE WORLD OF POLYMERS 2.1 Function of a seal 2.2 Polymer materials 2.3 Material abbreviations GENERAL MATERIAL SELECTION AND DESCRIPTIONS 3.1 Material selection 3.2 Material descriptions 3.3 All-purpose Rubbers NR – IR BR SBR 3.4 Speciality Rubbers IIR EPDM CR CSM NBR XNBR AU – EU ECO ACM AEM EVM FKM FFKM HNBR VMQ – FVMQ 3.5 Thermoplastic Elastomers (TPE) TPE-O TPE-V TPE-S TPE-U TPE-E TPE-A 3.6 Technical Thermoplastics PO POM PK PA PBT 2. 3. 30 34 36 36 36 44 48 48 48 50 50 52 53 54 54 55 56 57 58 60 61 62 63 64 65 66 68 69 70 72 72 73 74 75 76 77 78 78 80 81 82 84

3.7 High-Performance Thermoplastics PPS PPA PEI PEEK ETFE / PVDF PFA / FEP PTFE PAI 3.8 Duromers UF UP EP PF PI Composition of FST material designations 3.9 3.10 Variety of materials 4. UNDERSTANDING ELASTOMER FORMULATIONS 4.1 Formulation ingredients Rubber Fillers Plasticizers Processing aids Anti-Ageing agents Cross-linking system Additional additives 5. 5. CROSS-LINKING CHEMISTRY Cross-linking density Cross-linking characteristics Optimization of elastomer processing Compatibility of the cross-linking chemicals Cross-linking agents Cross-linking with Sulfur Cross-linking with Peroxides Tempering 5.1 5.2 6. CARRIER PARTS Design of the composite component Pretreatment of the carrier parts Production of the elastomer composite component Table of contents 85 85 86 88 89 90 92 94 96 97 98 99 100 101 102 103 103 104 104 105 105 107 109 109 111 113 114 114 115 117 117 117 118 120 121 123 124 124 125 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 31 X E D N I

Materials and Process Engineering 7. 7. FROM RAW MATERIAL TO FINISHED PART 7.1 Procedure 7.2 7.3 Mixture production Shaping and vulcanization Choice of shaping procedure Influence of the rubber compound Tool competence Overview of the shaping process Compression Molding Transfer Molding Injection Molding Cold runner technology Choice of procedure Extrusion process Roller-head System (Press) sintering of PTFE Plastic processing 7.4 7.5 8. TESTING METHODS Processing characteristics Static-mechanical properties Compression set Temperature-frequency behavior Influence of media: Storage tests Heat resistance, aging behavior Chemo-stress relaxation Service life 9. DAMAGE ANALYSIS 9.1 9.2 Damage analysis process Typical damage phenomena, causes and mechanisms Material defects Manufacturing errors Design error Mechanical stress Thermal stress Explosive decompression Climatic stress 10. DEFECT CHECKS 32 126 126 126 130 130 132 132 133 133 133 134 135 135 136 138 139 141 143 144 147 151 152 154 156 157 158 163 163 166 166 167 170 170 172 173 174 177

11. PROPER STORAGE Storage conditions Suggestions for the assessment of elastomer components after the initial storage period 12. CHEMICAL RESISTANCE 13. SUMMARY OF THE STANDARDS MENTIONED 14. EXCURSUS: COMMON TERMINOLOGY IN THE RUBBER INDUSTRY Table of contents 178 178 179 180 213 216 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 33 X E D N I

Materials and Process Engineering 1. HISTORY A LONG HISTORY Rubber is a fascinating material with a long and varied history. Natural rubber has been used for thousands of years; the oldest known items made of rubber come from Central America and are over 3,500 years old. Natural rubber appears again and again in historical accounts. There are reports of children in the Amazon region playing with a small, bouncy, rubber- like ball, and indigenous peoples who had waterproof raincoats. Rubber is mentioned in Europe for the first time in the 16th century, and this was followed by the invention of the eraser and the impres- sive demonstration by physics professor Jacques Alexandre Cesar Charles, who was able to seal a balloon filled with hydrogen with the help of latex milk in 1783. Groundbreaking discovery Despite all these early uses of latex milk, the real success story only began with the groundbreaking discovery of Charles Nelson Goodyear. Goodyear was a tinkerer and inventor and experimented with natural rubber for many years. He wanted to de- velop a non-sticky, odorless and temper- ature-resistant impregnation for fabrics, which he surprisingly succeeded in doing in 1839. There are various stories about exactly how his discovery came about. One tells how he hid the last of the rubber-sulphur mixture from his wife in his hot oven. When he looked at the mixture again the next morning, he realized that it had changed significantly: from soft and sticky to dry and elastic. Since the transformation of plastic natural rubber into elastic rubber was achieved with the help of sulphur and heat, he named the process "vulcanization," after the Roman god of fire, Vulcan. Unfortunately, Goodyear was not a clever businessman, so despite his revolutionary invention, which even earned him an invi- tation to the first World's Fair in London in 1851, he was never commercially success- ful and died impoverished at the age of 59. Temporary monopoly With the commercialization of the pneu- matic tire by John Boyd Dunlop in the late 19th century, the demand for natural rubber exploded. Rubber trees (Hevea brasiliensis), from whose bark the latex sap is extracted, were mainly native to the Amazon basin, and Brazil was very protective of its economic supremacy. The export of seeds or plants was strictly forbidden – it was punishable by death. Nevertheless, the Englishman Henry Wickham managed to smuggle germinable seeds to England in 1876. This broke Brazil's monopoly and around the turn of the century, the first rubber plantations were established in Ceylon and other English colonies in the tropical and subtropical climates of Southeast Asia. Even today, the majority of natural rubber comes from this region. The former world market leader Brazil has completely lost its economic importance, not least due to a fungus that makes the plantation cultivation of rubber trees in South America largely un- profitable today. The era of synthetic rubber The demand for natural rubber also rose sharply when the wave of motorization began in Europe at the beginning of the 20th century and significantly more tires were needed. 34

1. History The first patent for synthetically pro- duced rubber was granted in 1909: Fritz Hofmann had invented methyl rubber. At the end of the 1920s, an industrial process made it possible to produce styrene- butadiene rubber (SBR) for the first time. The first fully synthetic rubber was in- vented by Ivan Kondakov in 1901. Two other synthetic rubbers were also devel- oped at this time: nitrile rubber (NBR) and chloroprene rubber (CR). Today, the rubber industry uses around 25 classes of synthetic rubber in addition to natural rubber, which still accounts for around 40% of the rubber used worldwide. Exciting future The history of rubber is extraordinary and the triumph of this elastic material con- tinues unabated. Whether hoses or baby pacifiers, shoe soles or V-belts, seals or conveyor belts, tires, vibration dampers or baking tins: the portfolio of rubber products has never been as diverse as it is today. In addition to the ongoing specialization of elastic materials, careful handling is becoming increasingly important. This applies both to the raw materials and their processing as well as to the disposal and recycling of the products. New challenges are currently arising from changes to chemicals legislation and in- creased volatility in supply chains. There is also an increasing focus on legislation and the desire of a growing number of customers for more sustainable solutions and meaningful sustainability reporting. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 35 X E D N I

Materials and Process Engineering 2. INTRODUCTION TO THE WORLD OF POLYMERS 2.1 FUNCTION OF A SEAL GENERAL SEALING EFFECT Surfaces are never smooth; every surface has microscopic imperfections. Surface treatments such as grinding or polishing can reduce the roughness, but this is not enough to seal against liquids or gases. What is needed is a material that adapts so well to the surface roughness that it largely compensates for it and thus clos- es leakage paths. This completely sepa- rates the installation spaces on both sides of a seal. Rubber is by far the first choice here: elastomers have the necessary flexibility to adapt to the surfaces of the compo- nents and at the same time the rigidity to remain dimensionally stable. CLASSIFICATION OF SEALING PRINCIPLES Sealing applications can be divided into two categories: Static seals are used to seal two station- ary components together. Typical appli- cations are seals for closures or flanges – the O-ring is one of the most common static seals. Surface roughness does not create a sealing effect A seal compensates for surface roughness and seals it off Fig. 1 General sealing effect of gaskets 36 Dynamic seals mutually seal two compo- nents that move relative to each other. Depending on the type of movement, a distinction is made between rotary seals (shaft seals) and translatory seals (e.g. piston or rod seals). A distinction is also made between con- tact and non-contact seals. The latter are largely friction-, abrasion- and heat-free, but at the cost of higher leakage rates. The sealing mechanisms of the two categories differ fundamentally and are explained in more detail in the respective chapters of this manual. 2.2 POLYMER MATERIALS Polymer material is a collective term for materials that consist of very large, mostly chain-like molecules, called macromole- cules or polymers. Natural representatives of this class of materials are animal and plant fibers such as silk, wool, cotton or cel- lulose; substances such as starch or gelatin and natural rubber are also natural poly- mers. However, the majority of polymers in use today are produced synthetically (artificially → "plastics"). Low molecular weight building blocks combine in the polymerization reaction to form long polymer chains with molecular weights between 10,000 and 10 million g/mol. Polymers that consist of only one type of monomer are called homopolymers; if they are made from two or more different monomers, they are called copolymers. PROPERTIES Unlike low-molecular substances, polymers do not usually crystallize when a liquid polymer melt cools, but are amorphous

2. Introduction to the world of polymers I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I at rest moving Seals R O F S L A E S Y R A T O R S N O T A C I I L P P A Static seals Dynamic seals rotating moving linear moving Contact Non-contact Shaft seals Rod, piston and linear-guided seals R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Venting O-ring Bellows seal Profile seal Flat seal Membrane seal Fig. 2 Classification of seals (= non-crystalline) in the solid aggregate state. The arrangement of the polymer chains in the amorphous solid does not follow any rules, the polymer chains are tangled up, a bit like a molecular pile of spaghetti. Polymers with a particularly regular molecular chain structure can crystallize, but never completely, only in sections along the chain; they are partial- ly crystalline. For crystalline solids, the phase transition from solid to liquid is called melting. The reverse process during cooling is called crystallization. In the case of amorphous materials, these processes are referred to as softening and solidification, respectively. The associated phase transition is called the glass transi- tion point. The chemical and thermal resist- ance of polymer materials is also largely Contact Non-contact Contact Stuffing box Mechanical seal Radial shaft seal Gap seal Labyrinth seal Grooved ring Wiper Compact seal S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P determined by the structure of the polymer chains. For example, the main chain of a polymer can consist of carbon atoms strung together, but it can also contain other atoms such as oxygen, nitrogen or silicon. Additional atoms or molecular groups, the so-called side groups, are attached to the atoms of the main chain. These can be hydrogen, chlorine or fluorine atoms as well as alkyl, nitrile or ester groups and many more. amorphous semi-crystalline Fig. 3 Amorphous vs semi-crystalline C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 37 X E D N I

Materials and Process Engineering so great that the molecules of the liquid cannot penetrate the polymer. Non-polar substances There are only weak attractive forces be- tween the molecules of non-polar sub- stances, the Van der Waals forces. These are based on induced dipoles. Non-polar substances are only dissolved by non-polar media. Examples of non-polar media in- clude classic fuels or mineral oils. Polar substances The stronger dipole forces act between the molecules of polar substances. In contrast to the Van der Waals forces, these are based on permanent dipoles. Polar polymers can only be swollen or dissolved by polar media. Water, alcohols, glycols and ester oils are examples of polar media. The temperature resistance of the polymer results from the stability of the chemical bonds of the polymer molecule: a car- bon-carbon (C-C) double bond is less stable than the corresponding single bond, a car- bon-fluorine bond is more stable than a carbon-chlorine bond. C-C double bonds are an easy target for ox- ygen and especially ozone, so that polymers with many double bonds in the main chain cannot withstand high temperatures or ag- gressive media. Saturated polymers with- out double bonds are generally more resist- ant to ageing. To assess the resistance of polymer mate- rials to liquids or gases, it helps to compare the polarities of the two substances. If the polymer and liquid are chemically very sim- ilar, the liquid will interact strongly with the polymer, i.e. penetrate its structure and cause it to swell, or dissolve completely. "Similia similibus solvuntur," or "similar things dissolve in similar things," is one of the basic principles of chemistry. If the polarities of the liquid and polymer are very different, the dissolution process is prevented: The forces between the indi- vidual molecules of the liquid and the indi- vidual molecules of the polymer are then NR NBR Fig. 4 Natural rubber: NR: non-polar – only C and H; nitrile rubber: NBR: polar due to the nitrile group CN 38

2. Introduction to the world of polymers PI PAI TPI PES PEI PPSU PSU PEKK PEEK PTFE LCP PPS PA46 PPA I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P e High Performance Polymers c n a m r o f r e p d n a e c i r P Engineering Polymers PC PMMA PPE PBT PET PA66 PA6 POM PK Commodity Polymers ABS PVC PS SAN PE PP amorphous semi-crystalline Fig. 5 Material pyramid of thermoplastics S L A E S C I T A T S Elevated temperatures promote interac- tion and thus swelling or dissolution. The contact with a liquid often also causes the exchange of certain components of the medium and the polymer material, such as plasticizer oils or anti-ageing agents. This does not necessarily change the volume, but important constituents migrate from the polymer matrix into the surrounding medium, which significantly changes the properties and contaminates the medium itself with the extracted substances. POLYMER CLASSES Polymer materials are usually divided into four classes, which differ significantly in the temperature curve of their stiffness (their modulus) (see also → Material over- view table, page 44). Thermoplastics Thermoplastics are the largest of the four polymer classes in terms of volume. They consist of linear or branched molecular chains. The spatial order of the molecular struc- ture determines whether a thermoplastic is amorphous or semi-crystalline. The crys- tallinity has a considerable influence on the mechanical properties and processing behavior. For example, it determines how hard, ductile, brittle or tough a material is. Thermoplastic materials soften or melt at high temperatures and thus become plastically deformable. Even before the phase transformation point is reached, the tendency to creep under load increas- es significantly. Most thermoplastics are soluble in suitable solvents. Thermoplastics are divided into three class- es: standard thermoplastics, engineering thermoplastics and high-performance thermoplastics and are often shown as a material pyramid as in → Fig. 5. G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 39 X E D N I

Materials and Process Engineering Standard thermoplastics are inexpensive bulk plastics with moderate mechanical properties and temperature resistance not significantly above +100 °C. They are mainly used in the packaging and con- struction industries. They are mainly used in the packaging and construction industries and account for around 80% of the global volume of plastics. Engineering thermoplastics have better mechanical properties and are therefore suited for more demanding technical applications that require higher stiffness and strength or higher temperature or chemical resistance. High-performance thermoplastics, also known as high-performance polymers (HPP), are materials that are used for spe- cial applications and account for signifi- cantly less than 1% of the annual volume of plastics. Their continuous service tem- peratures are above +150 °C, they have high ageing and dimensional stability, cou- pled with high chemical resistance and often outstanding mechanical properties. External applied force leads to a state of higher order At rest Fig. 6 Entropy elasticity 40 Elastomers Elastomers consist of a special type of poly- mer called rubber. Rubbers are generally amorphous and have a low glass transition point of well below 0 °C. Through chemical reaction with suitable cross- linking chem- icals, the individual polymer chains are linked during vulcanization to form a wide- meshed three- dimensional network. This is how elastic rubber is created from rubber that is plastically deformable under heat. Due to the chemical bonding of the rubber chains with each other, elastomers can neither melt nor dissolve, but they swell strongly if the rubber and liquid have the same polarity. The reason for the elasticity of rubber can be found in its molecular structure: The effect of an external force forces the tan- gled polymer chains to align themselves from their state of equilibrium in the direction of the force. This ordering of the macromolecules costs energy, as it is accompanied by a reduction in disorder, or entropy. The chemical cross-linking of the polymer chains in the rubber prevents the chain segments from sliding irrevers- ibly against each other. Once the load has been relieved, the macromolecules seek to return to their (disorderly), energetically more favorable state of equilibrium. The deformation occurs spontaneously as soon as the force is no longer applied. The driving force behind the elastic be- havior of rubber is therefore entropy minimization. This type of elasticity is therefore called entropy elasticity or rubber elasticity. Entropy-elastic behavior is observed in large strains up to several hundred percent.

2. Introduction to the world of polymers Elastomers only behave entropy-elastically above their glass point, below this they are leathery or hard like glass, and often brittle. Rubbers are divided into tire rubbers and special rubbers based on their main ap- plication. Typical elastomer applications in everyday life are rubber bands, balloons and tires, but also all kinds of seals, baby pacifiers and gloves. Duromers Like elastomers, duromers are chemically cross-linked polymers, however the degree of cross-linking is significantly higher, so that a close-meshed network is created after the cross-linking reaction and the molecular chains cannot move against each other. The mechanical properties of duromers are only slightly dependent on temperature. They often have no glass point and undergo a direct decomposi- tion reaction above a certain tempera- ture without softening significantly be- forehand. Duromers are very resistant in contact with solvents: they are insoluble and do not swell. Duromers are characterized by a very low creep tendency and high strength. They are generally very abrasion-resistant and per- meation-tight. Their coefficient of thermal expansion is in the range of common metals such as steel and aluminum and is adjustable to a certain extent. Disadvan- tages of duromers are their usually very low elasticity and lower load-bearing capacity under tension than under compression. Sockets, cladding and casings are often made of duromers, and many adhesives and paints belong to this material class. Due to the weight savings and adjustable thermal expansion, duromer materials are increasingly being used as metal substitutes. More and more frequently, duromers can also be found in sealing applications. Thermoplastic elastomers Thermoplastic elastomers (TPE) are multi- phase systems and consist of solid hard phases and elastic soft phases. The hard phases are physical cross-linking points that disengage at high temperatures. TPE materials combine the properties of thermoplastics and elastomers in that they are plastically deformable under heat and behave elastically at service temperature. The soft phase is responsible for the elas- tic behavior and low-temperature flexi- bility, while the hard phase determines the strength and heat resistance of the material. The service temperature lies between the glass transition point of the soft segment and the glass transition point or melting point of the hard segment. Block copolymer Elastomer alloy Elastic segment Thermoplastic segment Elastomer Thermoplastic Fig. 7 Sketch of two TPE classes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 41 X E D N I

Materials and Process Engineering TPE Block copolymers Elastomer alloys Types of styrenes (TPE-S) Thermoplastic Polyolefins Polyether esters (TPE-E) (partially) cross-linked (TPE-V) Polyurethanes (TPE-U) non-cross-linked (TPE-O) Polyetheramides (TPE-A) Fig. 8 Classification of TPE materials Other thermoplastic vulcanizates (MPR *, EA **) * Melt Processable Rubber ** Elastomeric Alloys When the temperature is increased, the material becomes flowable due to the melting of the hard phase and can be pro- cessed thermoplastically. After the material has cooled and solidified, the physical cross-linking points form again, so that the TPE material regains its original mechanical properties and is therefore also recyclable. Due to the physical cross-linking, the material prop- erties of TPE are not only determined by their composition, but also to a large extent by their morphological structure. Hard and soft phases can be produced in the same molecule in the form of different molecular segments, but also as a mixture of elastomers in thermoplastics. As out- lined in → Fig. 8, TPE materials are divid- ed into two classes: block copolymers and elastomer alloys (also known as polymer blends or elastomeric alloys). The polymer chains of block copolymers consist of two different monomers. One chain segment (block) is amorphous and has a low glass transition point; these chain segments are flexible at service temperature. The other segment has a high glass transition point or is partially crystalline with a melting point well above the service temperature; these chain segments are rigid. Due to their incompatibility, the segments demelt; hard domains form in a flexible matrix. If the temperature is below the glass transition or melting point of the hard domains, the material behaves entropy- elastically; above this, the block copolymer melts. 42

2. Introduction to the world of polymers Elastomer alloys are mixtures of thermo- plastics and non-cross-linked rubber or cross-linked elastomer. When producing these mixtures, it must be ensured that the rigid thermoplastic phase forms the continuous phase (matrix); the flexible rubber phase is dispersed in it in the form of small flexible beads. The smaller the elastomer beads are, the better the prop- erties of the alloy are. High-quality soft-touch handles and buttons are often made of TPEs. TPEs are also used as mold and profile seals, as cable grommets, in children's toys and, due to their purity, in a wide range of medical and food technology applications. → Fig. 9 shows the modulus of elasticity as a function of temperature for the four polymer classes. Here too, the following applies: below the glass transition or melting temperature of the hard domain, the TPE behaves elas- tically; above this temperature, it softens and can be molded using standard thermo plastic processing methods. Thermoplastic Thermoplastic elastomer Elastomer Duromer l s u u d o m E - l s u u d o m E - l s u u d o m E - l s u u d o m E - Temperature Temperature Temperature Temperature = Service range = Cross-linking points Fig. 9 Schematic structure and temperature behavior of individual plastics I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 43 X E D N I

Materials and Process Engineering 2.3 MATERIAL ABBREVIATIONS OVERVIEW There are common abbreviations for all polymers that make it easier to deal with the often unwieldy material designations; they are defined in internationally valid material standards. Thermoplastics and duromers are usually named according to the abbreviations listed in DIN 7728-1, ISO 1043.1 or ASTM D 1600. For rubbers, the standards ASTM D 1418 and the largely identical ISO 1629 list the abbreviations. Rubbers are subdivided into various groups based on the structure of the main chain. The abbreviations for thermoplastic elastomers (TPE) can be found in DIN EN ISO 18064. The following table summarizes the ma- terial abbreviations of the most relevant sealing materials. The polarities of the polymers have been roughly categorized to provide an initial indication of chemical compatibility. More detailed information on the resistance of the most important rubbers can be found in → “12. Chemical resistance”, page 180. BRIEF DESCRIPTION CHEMICAL DESIGNATION OF THE BASE POLYMERS non- polar semi- polar polar ELASTOMERS BRIEF DESIGNATION ACCORDING TO ASTM D 1418/ISO 1629 R group: unsaturated hydrocarbons NR IR BR SBR IIR CIIR BIIR CR NBR X X X X X Natural rubber Isoprene rubber Butadiene rubber Styrene-butadiene rubber Butyl rubber Chlorobutyl rubber Bromobutyl rubber Chloroprene rubber Nitrile rubber X X X X Tab. 1 Designations and polarities of the most common polymers 44

2. Introduction to the world of polymers BRIEF DESCRIPTION CHEMICAL DESIGNATION OF THE BASE POLYMERS non- polar semi- polar polar R group: unsaturated hydrocarbons XNBR HNBR XHNBR carboxylated nitrile rubber Hydrogenated nitrile rubber Carboxylated hydrogenated nitrile rubber M group: saturated hydrocarbons EPM EPDM CM CSM EVM ACM AEM FKM FEPM FFKM Ethylene-propylene rubber Ethylene propylene diene rubber Chlorinated polyethylene X X Chlorosulfonated polyethylene Ethylene-vinyl acetate rubber Acrylic rubber Ethylene acrylate rubber Fluororubber Tetrafluoroethylene propylene rubber Perfluoro rubber Q-group: Silicon in the main chain MQ VMQ PVMQ FVMQ Silicone rubber Silicone rubber Phenyl silicone rubber Fluorosilicone rubber X X X X X X X X X X X X X X X I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 45 X E D N I

Materials and Process Engineering BRIEF DESCRIPTION CHEMICAL DESIGNATION OF THE BASE POLYMERS non- polar semi- polar polar O group: oxygen in the main chain CO ECO Epichlorohydrin rubber Ethylene oxide- epichlorohydrin rubber U group: carbon, oxygen and nitrogen in the main chain AU EU Polyester urethane rubber Polyether urethane rubber THERMOPLASTICS BRIEF DESIGNATION ACCORDING TO DIN 7728-1, ISO 1043.1, ASTM D 1600 PE PP POM PK PBT PA PPA PPS PEI PEEK PAI ETFE PVDF X X Polyethylene Polypropylene Polyoxymethylene Polyketone Polybutylene terephthalate Polyamide Aromatic polyamide Polyphenylene sulfide X Polyetherimide Polyetheretherketone Polyamideimide Ethylene-tetrafluoro- ethylene copolymer Polyvinylidene fluoride X X X X X Tab. 1 Designations and polarities of the most common polymers 46 X X X X X X X X X

2. Introduction to the world of polymers BRIEF DESCRIPTION CHEMICAL DESIGNATION OF THE BASE POLYMERS non- polar semi- polar polar THERMOPLASTICS BRIEF DESIGNATION ACCORDING TO DIN 7728-1, ISO 1043.1, ASTM D 1600 PFA FEP PTFE Perfluoroalkoxy copolymer Fluorinated ethylene- propylene copolymer Polytetrafluoroethylene THERMOPLASTIC ELASTOMERS ABBREVIATION ACCORDING TO DIN EN ISO 18064 Block copolymers TPS TPU TPC TPA Blends TPO TPV Thermoplastic styrene block copolymers Thermoplastic polyurethane Thermoplastic copolyester elastomers Thermoplastic polyamide elastomers Olefin-based thermoplastic elastomers Thermoplastic vulcanizates X X X X X X DUROMERS BRIEF DESIGNATION ACCORDING TO DIN ISO 1043.1/ASTM D 1600 UF PF UP EP PI Urea-formaldehyde resin Phenol-formaldehyde resin Unsaturated polyester Epoxy resin Polyimide X X X X X X X X I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P ASTM = American Society for Testing and Materials; ISO = International Organization for Standardization; DIN = Deutsches Institut für Normung e.V. 47 X E D N I

Materials and Process Engineering 3. GENERAL MATERIAL SELECTION AND DESCRIPTIONS intended to be a substitute for a materials science book. The selection of represent- ative thermoplastics, TPEs and duromers has been limited to those materials that are relevant for sealing technology. 3.1 MATERIAL SELECTION Selecting the best suited polymer material for a specific sealing application is a key task in material development. It requires in-depth knowledge of the specific prop- erties of polymers and the possibilities of tailoring materials to the application through compounding. A good technical understanding of the seal, its exact installation situation and the load spectrum of operating temper- ature, media contact and mechanical load is also important. Special requirements such as flame behavior or wear protection must also be taken into account. Ultimately, seal development can only succeed if the material, manufacturing process and seal design work together successfully. 3.2 MATERIAL DESCRIPTIONS The following table lists the basic prop- erties of the most important elastomer classes and the typical areas of applica- tion. It should be noted once again that such categorizations are always somewhat imprecise and do not take into account the sometimes considerable ranges within a rubber class. The properties of an elastomeric material can also be varied within certain limits through the clever use of fillers, anti-ageing agents and co- ordinated cross-linking systems. The most important polymer materials are explained below; of course, this level of detail also has its limits and is not Resistance Guide 48

I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P ‒40 / +140 D D + − +++ D +++ +++ +++ D VMQ ‒60 / +200 + D +++ −− −− +++ D +++ − B + + + +++ Oil and fuel hoses, rollers Cables, films, hoses, seals FVMQ ‒80 / +175 B D +++ −− D +++ +++ +++ +++ B +++ +++ Aviation, fuel and turbocharger hoses, diaphragms, seals SBR ‒50 / +100 FKM ‒25 / +200 HNBR ‒40 / +150 NBR ‒40 / +100 + + + + + + + D +++ B D + + + + −− + −− −− − −− D Tires, conveyor belts +++ +++ +++ +++ +++ +++ +++ Aviation, turbocharger hoses, diaphragms, seals +++ +++ +++ +++ +++ −− +++ Toothed belts, rod and piston seals −− + −− +++ D −− D Automotive parts, fuel/oil hoses, for foodstuffs such as milk + + ++ CIIR, BIIR ‒40 / +120 −− D IIR ‒40 / +120 −− D −− +++ +++ D −− +++ +++ +++ + + + −− NR, IR ‒60 / +80 +++ +++ +++ +++ −− −− +++ −− −− ‒60 / +100 B +++ +++ +++ −− −− +++ −− −− + + − − +++ +++ −− + −− −− Inner tubes, inner liners, vibration dampers Inner tubes, inner liners, vibration dampers Tires, conveyor belts, highly elastic articles, high-performance tires, consumer goods for foodstuffs −− −− Tires, conveyor belts, dynamically highly stressed articles + + + + 3. General material selection and descriptions e c n a t s i s e r e r u t a r e p m e T e c n a t s i s e r l a c i m e h C e c n a t s i s e r e m a l F AREAS OF APPLICATION C ° e g n a r e r u t a r e p m e T t e s n o i s s e r p m o C h t g n e r t S e c n a t s i s e r n o i s a r b A e c n a t s i s e r r e h t a e W s s e n t h g i t s a G e c n a t s i s e r r e t a W e c n a t s i s e r e n o z O y t i l i b i x e l f d o C l e c n a t s i s e r l i o l a r e n M i ‒40 / +150 + + + D + +++ + +++ D D −− +++ Oil hoses, seals ‒25 / +150 − D D D D +++ −− + +++ D −− +++ Oil hoses, oil pan seals MATERIAL AEM ACM ECO BR CR ‒45 / +100 B EPDM ‒50 / +150 + +++ Excellent ++ Good/Outstanding + Good + + + + + + + + D + + D +++ + Tires, conveyor belts, dynamically highly stressed articles D +++ +++ +++ −− + −− +++ Automotive profiles, cooling water/ steam hoses, window seals, construction profiles B Sufficient/Good D Sufficient − Moderate/unsuitable − − Unsuitable Tab. 2 Basic properties and typical areas of application of the most important elastomer classes 49 X E D N I

Materials and Process Engineering 3.3 ALL-PURPOSE RUBBERS NR – IR NATURAL RUBBER is the only rubber of natural origin. The rubber tree produces the white latex sap primarily to protect against animal predation and to seal wounds – chemically speaking, it is an aqueous dispersion of small natural rubber droplets – high molecular weight cis-1,4-polyisoprene. Rubber trees only grow in a narrow belt around the equator – the largest producers are Thailand and Indonesia. Like any natural product, the quality of natural rubber can vary signif- icantly over the course of the year and from plantation to plantation. Today, technically specified NR grades guaran- tee consistent quality for sophisticated products. NR vulcanizates are characterized by a number of special features: NR can crystallize spontaneously or under strain. For this reason, NR vulcanizates achieve high mechanical strength even without the addition of reinforcing fillers and are self-reinforcing at high elongations. NR –60° 0° +80° +/- highly elastic – + low TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES They are highly elastic, extremely wear- resistant and exhibit good flexibility at low temperatures. This combination of properties makes natural rubber an important raw material for the tire industry, which requires around 70% of the world's NR volume, mostly in blends with other tire rubbers. NR is also used in the production of vibration con- trol components such as engine, machine and construction mounts, bushings and rubber-metal spring elements. Shoe soles and conveyor belts are also made of nat- ural rubber. There are also a number of products that are made directly from la- tex: These include disposable gloves, baby pacifiers, condoms and balloons. Cis-1,4-polyisoprene is also produced syn- thetically today. The synthetic ISOPRENE RUBBER IR differs in terms of some details from its natural “brother” NR and is also mainly used in the tire industry. 50

3. General material selection and descriptions PROPERTIES y thermal application range of –60 °C to +80 °C. When exposed to higher temperatures for longer periods, natural rubber can soften after pre- viously hardening y good media resistance in diluted acids and bases as well as in alcohols and glycol ether-based brake fluids y not resistant in mineral oils and greases, fuels and aliphatic, aromatic and chlorinated hydrocarbons y not very resistant to ozone and UV light y high strength even without rein- forcing fillers y highly elastic y resistant to abrasion and fatigue I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 51 X E D N I

Materials and Process Engineering BR –70° 0° 0° +85° +/- fatigue-resistant – + low TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES BR BUTADIENE RUBBER or cis-1,4-polybuta- diene is produced from the monomer butadiene. BR is characterized by high elasticity and abrasion resistance, and is very fatigue- resistant and therefore dynamically high- ly resilient. Its low glass transition temper- ature of below –100 °C ensures outstanding flexibility at low temperatures. As a pure hydrocarbon, it has the same chemical re- sistance as natural rubber. BR is difficult to process due to its low tack and is almost always used in blends with NR, IR or SBR. BR improves the fatigue re- sistance and low-temperature behavior of the blends and is mainly used in tires, es- pecially in the tread and sidewall, as well as in higher quantities in winter tires. BR is also used in vibration technology, V-belts, conveyor belts and shoe soles. The core of golf balls is made of BR. Buta- diene rubber is also used for impact mod- ification of brittle thermoplastics. PROPERTIES y thermal application range of –70 °C to +85 °C y good media resistance in dilute acids and bases, in alcohols and water y not resistant in mineral oils and greases, fuels, aliphatic, aromatic and chlorinated hydrocarbons y highly elastic y bending crack resistant y not very resistant to ozone and UV light y mainly used in blends with NR, IR, SBR 52

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I SBR –40° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +100° +/- abrasion-resistant – + low + R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES O SBR STYRENE BUTADIENE RUBBER is a static copolymer comprised of butadiene and styrene. SBR rubbers are the most com- monly used synthetic rubbers in terms of volume. A distinction is made between emulsion and solution polymers, E-SBR and S-SBR (E = emulsion, S = solution) according to the two manufacturing processes. glass transition temperature of styrene. SBR vulcanizates are more resistant to abrasion than elastomers made from natural rubber, which is why SBR is mainly used for the production of tire treads. Many SBR rubbers are available in the form of standardized grades with uniform designations. Like NR, IR and BR, styrene butadiene rub- bers are typical tire rubbers. SBR vulcaniza- tes are characterized by a high reinforcing effect of filled grades, low hysteresis loss- es and thus low rolling resistance as well as high wet slip resistance due to the high Besides tires, materials made of SBR are preferred for the production of insulating mats, floor coverings, conveyor belts, con- struction profiles and sealing elements for hydraulic brakes. PROPERTIES y thermal application range of –40 °C to +100 °C y good media resistance in acids and bases as well as in alcohols and glycol ether-based brake fluids y unstable in mineral oils, greases, fuels and aliphatic, aromatic and chlorinated hydrocarbons y highly abrasion-resistant – better than NR y not very resistant to ozone and UV light y high reinforcing effect R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 53 X E D N I

Materials and Process Engineering 3.4 SPECIALITY RUBBERS IIR BUTYL RUBBER IIR – CIIR/BIIR –40° +130° 0° +/- low – + low TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY GAS PERMEABILITY IIR BUTYL RUBBER is a copolymer of isobuty- lene with a small proportion of isoprene. The halogenated rubbers CHLOROBUTYL RUBBER CIIR and BROMBUTYL RUBBER BIIR are obtained by a subsequent reaction with elemental chlorine or bromine. IIR vulcanizates have good resistance to weathering, ageing and ozone, which is due to the low proportion of double bonds in the main chain. The halogenated rubbers show slightly better setting behavior and slightly better heat and fatigue resistance. The gas and water vapor permeability of IIR vulcanizates is low. The media com- patibility is comparable to that of tire rubbers. Butyl rubber is used for insulating cable and sheathing, protective clothing and adhesives. The halogenated types are used to make tire tubes and the inner layers of tubeless tires. Halogenated butyl rubbers are also used for the heating bellows required for the vulcanization of tires, for pharmaceutical articles such as stoppers and closures and for mold seals. PROPERTIES y thermal application range –40 °C to +130 °C y good media resistance in glycol ether-based brake fluids, inorganic and organic acids and bases, hot water and steam up to +120 °C y unstable in mineral oils and greases, gasoline and aliphatic as well as aro- matic and chlorinated hydrocarbons y high damping y low gas permeability y bending crack resistant 54

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I EPDM –50° 150° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- weather resistant – + low + R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MECHANICAL PROPERTIES EPDM ETHYLENE-PROPYLENE-DIENE RUBBER is a copolymer of ethylene, propylene and up to 12% of a diene. The most common diene component is the ethylidene nor- bornene shown in the formula. EPD M rubbers with an ethylene content of over 60% can crystallize. The higher the ethylene content, the higher the strength and the lower the flexibility at low temperatures. Ethylene-propylene rubbers (EPM), i.e. copolymers without a diene component, are also widely used. EPD M vulcanizates are highly resistant to ozone, ageing and weathering ("outdoor materials") and therefore the material of choice for sealing profiles in the auto- motive and construction industries and for cable sheathing. Its good resistance to glycol makes it well suited for use in hoses and seals for brake fluids and cooling water. Due to their good resistance to hot water and steam, EPD M materials are used for water-bearing components and for prod- ucts that come in contact with drinking water and aqueous foodstuffs. EPM is used for oil additivation and impact modification of thermoplastics. PROPERTIES y thermal application range of –50 °C to +150 °C y good media resistance in hot water, steam, washing lyes, oxidizing media, acids, bases, polar organic media, ketones, glycol ether-based brake fluids y unstable in mineral oils and greases, gasoline and aliphatic as well as aro- matic and chlorinated hydrocarbons y weather-resistant R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 55 X E D N I

Materials and Process Engineering CR –30° +110° 0° +/- fatigue-resistant – + medium + Cl TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES Like NR, CR tends to crystallize, which is why unfilled vulcanizates also exhibit high strength. Chloroprene rubber is used in the adhe- sives industry. Surfing and diving suits are made of CR, as are many hoses, cables and profiles. Conveyor belts and drive belts are also made from CR. In sealing technology, CR vulcanizates are used for molded seals as well as for bellows and dust caps. CR CHLOROBUTADIENE RUBBER is a poly- merizate based on chloroprene (chloro- butadiene). CR elastomers are known for their good resistance to ageing, weathering, ozone attack and high flame resistance. The polar carbon-chlorine bond is the reason for the good media resistance in simple mineral oils and greases. The chemical resistance of CR vulcanizates corresponds approximately to that of nitrile rubber NBR with an acrylonitrile content of 18%. CR vulcanizates show good mechanical strength and can with- stand dynamic loads. PROPERTIES y thermal application range of –30 °C to +110 °C y good resistance in mineral oils with a high aniline point, fats, alcohol, glycol ether, water, diluted acids and bases y medium resistance in mineral oils, low-molecular aliphatic hydrocar- bons such as gasoline and isooctane y unstable in aromatics, chlorinated hydrocarbons, esters, ketones y flame-retardant y fatigue-resistant 56

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- elastic CSM –30° +120° 0° – + high Cl SO2CL TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES CSM CHLORSULFONATED POLYETHYLENE re- sults from the reaction of thermoplastic polyethylene with chlorine and sulphur dioxide. Simultaneous sulphochlorination and chlorination make it possible to synthesize different types of CSM, which differ in terms of their chemical and tech- nical properties depending on the reaction process. CSM vulcanizates are highly elastic and very weather-resistant due to their satu- rated main chain. PROPERTIES As with chloroprene rubber (CR), the chlo- rine in CSM rubber leads to good flame resistance. CSM is highly resistant to acids and, with a high chlorine content, is also highly resistant to mineral oils. CSM is often used in the chemical indus- try for hoses and container linings. Other applications include colored cable sheath- ing, pond and roof films, coated fabrics, e.g. for inflatable boats, seals and mem- branes. y thermal application range –30 °C to +120 °C y good media resistance in hot wa- ter, steam, washing lyes, oxidizing media, acids, bases, polar organic media, ketones, glycol ether-based brake fluids y medium resistance in aliphatic hy- drocarbons and fats, strong bases y unstable in aromatic, chlorinated hydrocarbons and esters y highly elastic y flame-retardant R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 57 X E D N I

Materials and Process Engineering NBR –30° +100° +/- abrasion-resistant 0° – + medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES CN NBR NITRILE RUBBER also called ACRYLO NITRILE BUTADIENE RUBBER is a copolymer of acrylonitrile (ACN) and butadiene. The ratio of the two monomers can be varied within wide limits and significantly in- fluences the property profile of the NBR vulcanizates; ACN contents of between 18 and 50 percent are quite common. The polar nitrile groups ensure good oil and fuel resistance, which increases as the ACN content rises. Elasticity and com- pression set deteriorate with increasing acrylonitrile content, while gas tightness increases. The low-temperature flexibility also depends significantly on the monomer ratio and ranges from –40 °C at 18% ACN to –5 °C at 50% ACN. NBR vulcanizates have high mechanical properties, are wear-resistant and highly damping. NBR vulcanizates are used for hoses, floor coverings and in sealing technology: Seals of all kinds are always made from NBR if the maximum operating temperatures do not significantly exceed +100 °C and good oil resistance is required. Important fields of application include automotive and me- chanical engineering, oil and gas exploration and gas supply. In addition to static seals, NBR materials are also used to manufacture radial shaft seals – Simmerings and sealing elements for hydraulics and pneumatics. Freudenberg Sealing Technologies has been working with nitrile rubber longer than any seal manufacturer in the world. 58

3. General material selection and descriptions PROPERTIES y thermal application range of –20 °C to +100 °C y good media resistance in mineral oils, vegetable and animal oils and greases, light heating oil, diesel fuel y some materials are particularly resist- ant in hot water up to +100 °C, inor- ganic acids and bases at not too high concentrations and temperatures y medium media resistance in fuels with a high aromatic or alcohol con- tent, additivated oils y unstable in aromatic and chlorinated hydrocarbons, esters, polar solvents as well as in glycol ether-based brake fluids I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 59 X E D N I

Materials and Process Engineering XNBR –25° +100° 0° +/- abrasion-resistant – + medium + CN COOH TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES The main applications are drive belts, hydraulic hoses, roller covers and high- quality shoe soles. In sealing technology, XNBR is used when dynamic applications require special wear resistance and the setting behavior is of secondary impor- tance. XNBR CARBOXYLATED NITRILE RUBBER is a ter- polymer made from acrylonitrile (ACN), butadiene and a carboxylic acid. The main properties are comparable to NBR poly- mers, but XNBR is characterized by higher strength, better tear resistance and high dynamic load-bearing capacity. The ageing behavior, setting behavior and low-temperature flexibility are slightly worse compared to NBR. PROPERTIES y thermal application range of ‒25 °C to +100 °C y better compared to NBR: strength and abrasion resistance; better dynamic properties y worse compared to NBR: setting behavior, water and aging resist- ance 60

3. General material selection and descriptions R1 O O O N H R2 N H AU/EU O –35° +110° +/- elastic 0° – + medium + I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES AU – EU URETHANE RUBBER is a rubber that is poly merized from polyol, diisocyanate and chain extenders. Depending on the composition of the polyols used, a distinction is made between polyester urethane rubber – AU and polyether urethane rubber – EU. Vulcanizates made of urethane rubber are characterized by excellent wear and abra- sion resistance, high tensile strength, high elasticity and good resistance to high- energy radiation. They are resistant to oxygen, ozone, mineral oils and greases. Urethane rubbers are only partially resistant to aqueous media. On the other hand, EU rubbers are more resistant to hydrolysis than AU rubbers. The gas permeability is low and compa- rable to butyl rubber (IIR). Typical areas of application are wipers, gear wheels, rollers and roller coverings; these rubbers are also used in sealing technology. Another representative of the large class of polyurethane polymers is thermoplastic polyurethane (TPU): It belongs to the TPE polymer class and is used for seals in pneu- matics and hydraulics (see → “3.5 Thermo- plastic Elastomers (TPE)”, page 72.) PROPERTIES y thermal application range of –35 °C to +110 °C y good media resistance in mineral oils and greases, water-oil mixtures, sili- cone oils and greases y not resistant to polar solvents, chlo- rinated hydrocarbons, aromatics, glycol ether-based brake fluids, acids and bases, amines y also not resistant in hot water and water vapor R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 61 X E D N I

Materials and Process Engineering O O ECO CH2Cl –40° +140° 0° TEMPERATURE RANGE (°C) +/- low – + medium + MEDIA GAS- COMPATIBILITY PERMEABILITY ECO ETHYLENE OXIDE-EPICHLOROHYDRIN RUBBER is the main representative of the O class: it is a copolymer of ethylene oxide and epichlorohydrin. ECO vulcanizates are characterized by low gas permeability and good resistance to ozone and weathering combined with good low-temperature flexibility. They can withstand high dynamic loads and are also highly resistant to oil and fuel, while at the same time offering good re- sistance to acids and bases. PROPERTIES ECO vulcanizates have oil resistance comparable to nitrile rubber but are significantly more heat-resistant. They are used where good resistance to mineral oil and good resistance to weathering and ozone are required. The most important applications include oil and fuel hoses, roller covers and textile rubber linings, engine mounts as well as seals and diaphragms, especially for hy- draulic accumulators. y thermal application range of –40 °C to +140 °C y good media resistance in mineral oils and greases, vegetable and animal oils and greases, aliphatic hydrocarbons (propane, butane etc.) and gasoline as well as water y unstable in aromatic and chlorinat- ed hydrocarbons, flame-retardant hydraulic fluids of the HF D group 62

CSM ACM –30° +150° 0° C = C O = C O = C C O O C2H5 C4H9 CH2 CH2 O CH3 ACM ACRYLATE RUBBER is a copolymer of various acrylic acid esters with a small addition of another monomer required for cross-linking (CSM: cure site monomer). ACM vulcanizates are very resistant to ageing and ozone and show very good re- sistance to hot and highly additivated oils and lubricants. Depending on the monomer composition, they offer moderate to good low-temperature flexibility. PROPERTIES 3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- moderately elastic – + medium R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES Elastomers based on ACM are more heat-resistant than those based on NBR or CR, but have more moderate mechanical properties. ACM materials are mainly used in the automotive industry for hoses and seals: radial shaft seals – Simmerrings for gear- box sealing, O-rings and other molded parts such as valve cover or oil pan seals are made from ACM. y thermal application range of –30 °C to +150 °C y good media resistance in mineral oils, also in highly additivated engine, gear and ATF oils y unstable in aromatic and chlorinated hydrocarbons, alcohols, glycol ether- based brake fluids and flame-retard- ant hydraulic fluids y hot water, steam, acids, alkalis and amines have a destructive effect R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 63 X E D N I

Materials and Process Engineering O = C O CH3 COOH AEM ETHYLENE ACRYLATE RUBBER is a copol- ymer of ethylene and methyl acrylate. Compared to ACM vulcanizates, AEM elas- tomers are more heat-resistant and more flexible at low temperatures, and they usually offer higher strength. Chemical re- sistance to mineral oils is lower due to the ethylene component and is comparable to CR, while resistance to water and water/ glycol mixtures is higher than with ACM. Materials based on AEM are highly damping. PROPERTIES AEM –40° +160° 0° +/- damping – + medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES Like ACM, AEM rubber is also frequently used in the automotive sector: due to its high damping properties, oil and temper- ature-resistant vibration dampers are made from AEM vulcanizates. In addition to cable sheathing, AEM materials are used in hoses and seals for air ducting systems such as turbochargers as well as in engines and gearboxes. y thermal application range of –40 °C to +160 °C y good media resistance in additivated- and paraffin-based mineral oils y good weather and ozone resistance y unstable in ATF and gear oils, aro- matic-rich mineral oils, glycol ether- based brake fluid, esters, ketones and concentrated acids y in contrast to ACM, stable in water and water/glycol mixtures y high damping 64

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I EVM –40° +160° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- ﬂame-retardant – + medium + R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MECHANICAL PROPERTIES R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 65 X E D N I O O = C CH3 EVM ETHYLENE VINYL ACETATE RUBBER is a copolymer of ethylene and vinyl acetate with vinyl acetate contents of between 40 and 80%. EVM materials have good heat resistance and show a good balance between oil resistance and low-temper- ature flexibility. In contrast to ACM and AEM, EVM-based materials are not only highly resistant to water but also to vapor. EVM vulcanizates are halogen-free and yet flame-retardant; in the event of fire, the smoke gas density is low and the fire gases are not corrosive. Often blends with HNBR are used. One of the main areas of application for EVM vulcanizates is the cable industry due to its favorable fire behavior. Elastic floor coverings, roller coverings and the outer shells of fuel hoses are also made from EVM. EVM is also used in the adhesives industry, primarily as hotmelt and solvent adhesives and in sealing technology. PROPERTIES y thermal application range of –40 °C to +160 °C y good media resistance in water and water vapor y good resistance to weathering and ozone; sufficiently resistant in aliphatic hydrocarbons, mineral oils and greases y unstable in aromatic and chlorinat- ed hydrocarbons and esters y flame-retardant

Materials and Process Engineering FKM –20° 0° 0° +200° TEMPERATURE RANGE (°C) +/- low – + high MEDIA GAS- COMPATIBILITY PERMEABILITY In addition to FKM, there is the class of FEPM rubbers synthesized from TFE and propylene. They have a fluorine content of 57%, show excellent resistance to hot water, steam and basic media such as amines and amine-containing liquids with medium resistance to mineral oils. FKM-based materials are used in the auto- motive and commercial vehicle industry, in the aerospace industry, in food appli- cations and in oil production and plant engineering. In addition to turbocharger and fuel hoses, dynamic and static seals such as valve stem seals, radial shaft seals – Simmerrings, molded parts, O-rings, flat gaskets and diaphragms are manu- factured from FKM vulcanizates. Under the name Fluoroprene XP, Freuden- berg Sealing Technologies offers a special range of materials for use in the process and food industry whose properties sig- nificantly exceed those of conventional FKM materials. F F F F F CF3 FKM FLUORORUBBER is synthesized by poly- merization of vinylidene fluoride (VDF) and optional use of variable proportions of other monomers such as hexafluoro- propylene (HFP), tetrafluoroethylene (TFE) and perfluoromethyl vinyl ether (PMVE). Co-, ter- or tetrapolymers with different structures and fluorine contents of 65 to 71% and thus different media resistance and low-temperature flexibility (standard types –20°C; special grades –40°C) can be produced. FKM rubbers can be cross-linked using diamines, bisphenols or organic peroxides, depending on the type. The special importance of FKM materials lies in their high temperature resistance and chemical stability, both of which are the result of the high stability of the car- bon-fluorine bond. The gas permeability is low, the resistance to ozone, weathering and light cracking is outstanding. FKM vulcanizates are flame-retardant; bisphe- nolic cross-linked grades are more resistant to temperature and wear, but less resistant to acids and steam than peroxide cross- linked grades. Amines have a destructive effect on FKM materials, and standard FKM vulcanizates swell strongly in ketones and esters. 66

3. General material selection and descriptions PROPERTIES y thermal application range of –20 °C to +200 °C y good media resistance in mineral oils and greases (especially highly additivated engine oils), aliphatic and aromatic hydrocarbons such as gasoline y good resistance to weathering, hot air and ozone; sufficiently stable in aliphatic hydrocarbons, mineral oils and greases y FKMs with special peroxide cross- linking are also highly resistant to alcohols, hot water, steam and alco- hol-based fuels y unstable in ketones, esters, amines and additive oils and fats with a high amine content y low gas permeability I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 67 X E D N I

Materials and Process Engineering F F R F F F F F FFKM PERFLUORINATED RUBBER is produced by using special perfluorinated (i.e. com- pletely hydrogen-free) monomers and special compounding and processing techniques. FFKM combines the elastici- ty of an elastomer with a media and tem- perature resistance that surpasses FKM materials even further and comes very close to PTFE ("elastic PTFE"). FFKM com- pounds are not easy to process, the vul- canizates have poor low-temperature flexibility and the physical properties are rather moderate; FFKM materials are very expensive. FFKM vulcanizate is used wherever temperatures prevail that cannot be reached by any other elastic material or PROPERTIES FFKM –20° +/- abrasion-resistant 0° 0° +300° – + high + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES where near-universal chemical resistance is required. High-performance materials based on FFKM are mainly used as sealing materi- als in the chemical, oil production and processing industries, in apparatus and power plant construction and in the aerospace industry. Due to their high purity, vulcanizates made from FFKM are also used in the semiconductor industry and photovoltaics, in medical technology and in the pharmaceutical and food sectors. Freudenberg Sealing Technologies has been offering customized sealing solutions made from the company’s proprietary perfluoro- elastomer Simriz® for many years. y thermal application range for standard types of –10 °C to +230 °C (special grades –30 °C to +320 °C) y nearly universal chemical resistance, including to esters and ketones, amines, concentrated acids and bases y not resistant to alkali metals and per- fluorinated hydrocarbon materials y combines the durability of PTF E with the elasticity of an elastomer 68

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I HNBR –20° +150° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- abrasion-resistant – + medium + R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES CN HNBR HYDROGENATED ACRYLONITRILE-BUTA- DIENE RUBBER is obtained from NBR pol- ymers by a subsequent hydrogenation step in which the double bond content of the butadiene component is reduced to < 1 – 7%. This increases the heat and oxi- dation stability, especially in the case of peroxide cross-linking. High mechanical strength even at high temperatures as well as improved abrasion resistance and good dynamic resistance characterize the materials produced from this material. The media resistance is similar to that of NBR. As with NBR, there are CARBOXYLATED HNBR RUBBER, XHNBR with improved abrasion and tear resistance; also grades with special heat resistance and low-tem- perature grades. HNBR is often used in the automotive sector as a standard material for timing belts and hoses. However, this material is also used as a rod or piston seal, and radial shaft seals– Simmerrings are also made from HNBR. Due to its good resistance to crude oils, HNBR is also a common sealing material in oil exploration. PROPERTIES y thermal application range of –20 °C to +150 °C y media resistance comparable to NBR y very good weather and tempera- ture resistance y resistant to abrasion and fatigue R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 69 X E D N I

Materials and Process Engineering CH3 CH = CH2 CH3 R VMQ: R = – CH3 Si O Si O FVMQ: R = – CH2 – CH2 – CF3 PVMQ: R = O VMQ – FVMQ SILICONE RUBBERS are synthesized from different siloxane monomers. The polymer backbone consists alternately of oxygen and silicon atoms. VMQ vulcanizates are characterized in particular by high thermal stability and good low-temperature flex- ibility as well as very good resistance to oxygen, ozone and high-energy radiation. Tear resistance and abrasion resistance are moderate, the temperature depend- ency of the technological properties is low compared to other elastomers and the permeability for gases is significantly higher. Materials based on VMQ are highly electrically insulating, flame-retardant and physiologically inert. VMQ vulcaniza- tes are degraded by depolymerization at high temperatures in the absence of oxygen. PHENYL-VINYL-METHYL-POLYSILOXANE, PVMQ is a particularly cold-flexible variant of silicone rubber that retains its elastic properties down to –90 °C. FLUOROSILICONE RUBBER, FVMQ is com- posed of side groups that contain fluorine. Elastomers made from FVMQ are consid- erably more resistant in fuels, mineral, synthetic and aromatic oils than those VMQ –50° 0° 0° +/- elastic – + +200° medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES made from VMQ and PVMQ, their oper- ating temperatures range from –55 °C to +175 °C. Due to their purity and physiological in- ertness, silicone elastomers are used in the pharmaceutical industry, medical technology and in contact with food. Due to their high electrical resistance, they are used as potting compounds in electronics and as insulators on overhead power lines. In addition, hoses, membranes, cables and seals in the automotive and electrical in- dustries are made from VMQ. FVMQ vulcanizates are particularly well suited for inner hose layers (e.g. in turbo- charger hoses) and for seals in contact with fuels. Other fields of application include natural gas plants and natural gas con- veying equipment as well as aerospace technology. 70

3. General material selection and descriptions PROPERTIES y thermal application range of VMQ –50 °C to +200 °C y good media resistance in mineral oils, animal and vegetable fats (com- parable to CR materials) and in glycol ether-based brake fluids y can be used in water up to +100 °C; sufficiently resistant in aqueous salt solutions, monohydric and poly- hydric alcohols y unstable in low molecular weight esters and ethers, aromatic hydro- carbons y concentrated acids and bases, water and steam at temperatures above +100 °C and under pressure have a destructive effect y flame-retardant, not very gas-tight I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 71 X E D N I

Materials and Process Engineering 3.5 THERMOPLASTIC ELASTOMERS (TPE) TPE-O –40° 0° +100° +/- weather and ageing resistant – + medium TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MECHANICAL PROPERTIES TPE-O POLYOLEFIN-BASED ELASTOMER ALLOYS WITH A NON-CROSS-LINKED RUBBER PHASE: Elastomer alloys based on EPD M and isotactic polypropylene (iPP) are cur- rently the most important TPE-O material class for technical applications. The iPP forms semi-crystalline phases in the ma- terial and thus enables the material to be processed thermoplastically above the melting temperature. TPE-O are charac- terized by their high resistance to polar media, high resistance to weathering and ageing and their low density. The products cannot be used above +100 °C. TPE-O are mainly used for haptic applica- tions, in particular elastic ergonomic soft- touch handles (toothbrushes, tools and hair dryers, for example). They are also used in car interiors and for children's toys. PROPERTIES y thermal application range of –40 ˚C to +100 °C y good media resistance in water, washing lyes, acids and glycol- based brake fluids y low resistance to mineral oils, greases and gasoline y good resistance to weathering and ageing 72

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I TPE-V +120° –50° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- weather and ageing resistant – + medium R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MECHANICAL PROPERTIES TPE-V POLYOLEFIN-BASED ELASTOMER ALLOYS WITH A NON-CROSS-LINKED RUBBER PHASE: Like TPE-O, TPE-V are elastomer alloys made of thermoplastic and elasto- mer material, whereby the latter is often chemically cross-linked in the melt dur- ing production (dynamic vulcanization), resulting in the formation of stable elas- tomer domains. The size and degree of cross-linking of the elastomer domains are decisive for the mechanical properties of the material. EPDM/PP alloys, which are characterized by their good resistance in polar media and good resistance to weathering and ageing, are increasingly used in technical applications. Special grades are also available for applications in non-polar media. Conventional TPE-Vs generally cannot be used above +120 °C. TPE-V based on EPDM/PP are used for grommets, brake hose sheathing, plugs and cable glands. They are also widely used in consumer goods and in the healthcare sector. TPE-V is used to pro- duce profile seals for the automotive and construction industries. Molded seals of all kinds in medical and food technology, in drinking and wastewater, but also in household appliances are made from TPE-V. PROPERTIES y thermal application range of –50 ˚C to +120 °C y high media resistance in (hot) water, washing lyes, acids and glycol-based brake fluids y special grades for media resistance in oils and greases y high resistance to UV, weathering and ageing y increased mechanical strength values R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 73 X E D N I

Materials and Process Engineering n m n TPE-S –40° 0° +80° +/- scratch-resistant – + low TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES TPE-S STYRENE BLOCK COPOLYMERS: TPE-S are characterized by a three-block structure consisting of thermoplastic polystyrene hard segments as end blocks and an elas- tomer middle block. The following sty- rene block copolymers are differentiated according to the type of middle block: Butadiene (SBS), isoprene (SIS), ethylene/ butylene (SEBS), ethylene/propylene (SEPS), polyisobutylene (SIBS). The ratio of polystyrene to polydiene segments de- termines the mechanical properties of the material; its stiffness increases with increasing polystyrene content. The elastomer segment, on the other hand, significantly determines the material's resistance to thermo-oxidative ageing at the service temperature. Ready-to-use TPE-S materials are produced by com- pounding with other plastics, plasticizer oils, fillers and other additives. The softening point of the polystyrene hard phase deter- mines the application temperature limit: creep and loss of tensile strength occur above +100 °C. TPE-S are used to modify bitumen and asphalt. They are used as adhesives and hot-melt adhesives, in children's toys, in packaging and elastic soft-touch handles. Special grades based on SEBS and SEPS are used in medical technology, in food and drinking water applications and in car interiors. Simple sealing applications can also be realized with styrene block co- polymers. PROPERTIES y thermal application range of –40 ˚C to +80 °C y high media resistance in water, washing lyes, acids and glycol- based brake fluids y high resistance to UV, weathering and ageing y increased mechanical strength values 74

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I O O O O R O X X O o N H N H O n O 4 N H N H m TPE-U THERMOPLASTIC POLYURETHANE ELASTO- MERS: TPE-U are multiphase block co- polymers obtained from the reaction be- tween isocyanates, chain extenders and polyols. The long-chain polyol forms the soft segments, which determine the material's low-temperature properties and resistance to media and ageing. Iso- cyanate and chain extenders (e.g. short- chain diols) form thermally reversible physical cross-linking points. TPE-U are among the materials that are particular- ly characterized by their high strength, high flexibility, high resilience and low abrasion. They are resistant to fats and oils at extremely low temperatures (–50 °C) and high temperatures (up to +120 °C for short periods). PROPERTIES TPE-U +120° –50° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- abrasion-resistant – + high R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES This material is therefore often used in hydraulic applications. However, TPE-U is not resistant to acids or hot water. TPE-U is used to make sporting goods such as parts of sports shoes and ski boots, and certain types are suited for contact with food and skin. Hoses, cable sheathing, belts, films and profiles are also made from TPE-U, as are high-quality instrument panels. In sealing technology, TPE-U materials are used for highly stressed diaphragms and especially for rod and piston seals and wipers for hydraulics and pneumatics. y thermal application range of –50 ˚C to +120 °C y high media resistance in greases and oils y unstable in acids and hot water y very high mechanical strength values y high resilience y highly resistant to abrasion and fatigue R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 75 X E D N I

Materials and Process Engineering O O 4 O O O n O o O m O TPE-E THERMOPLASTIC COPOLYESTER-POLY- ETHER-ELASTOMERS: TPE-E are multi- block copolymers that consist of oxyalky- lene glycol units of different lengths that are connected to each other via polyester blocks. The polyether segments form the soft elastomer phase, while the polyester segments form physical cross-linking points. TPE-E are particularly characterized by their durability under dynamic loads, high strength and wear resistance. They have good low-temperature flexibility and are thermally resistant up to +120 °C. They are also resistant to non-polar media, but are not resistant to concentrated acids and PROPERTIES TPE-E +120° –65° 0° +/- fatigue-resistant – + high TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MECHANICAL PROPERTIES alkalis as well as hot water. TPE-E materials are a halogen-free and flame-retardant alternative to PVC. Cable insulation and sheathing, connec- tors and suspension systems are made from TPE-E, as are rollers and belts. TPE-E are used in air ducts, pipes and hoses. They are also used in sports equipment and medical technology. In the sealing sector, TPE-E are the ideal choice for dynamically highly stressed components subject to buckling, such as axle boots and bellows. y thermal application range of –65 ˚C to +120 °C y high media resistance in lubricants and oils y unstable in concentrated acids and alkalis, hot water and steam y very high mechanical strength values y high resilience across a wide tem- perature range y fatigue resistant 76

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I TPE-A –40° +120° 0° H N O O 11 n 4 4 m O O O R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- impact-resistant – + medium R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES TPE-A POLYETHER POLYAMID E BLOCK COPOLY- MERS: TPE-A are block copolymers in which the polyether blocks form the elastomeric phase, while the polyamide blocks act as the thermoplastic hard phase. They are characterized by high flexibility and high resilience over the entire service temperature range. In addition, TPE-A have good abrasion and sliding properties and high notched impact strength even at low temperatures. They are only partially resist- ant to acids, alkalis and non-polar media. They are used in medical technology, for example, and are temperature-resistant up to +120 °C. TPE-A are used in sporting goods such as the outsoles of sports shoes and parts of ski boots. Conveyor belts, belts, transmission parts such as gear wheels, pressure lines and airbag covers are made from TPE-A ma- terials. Special grades are used in medical technology, particularly in catheters. PROPERTIES y thermal application range of –40 ˚C to +120 °C y limited resistance to acids, lyes, oils and greases y high mechanical strength values y high notched impact strength y high elasticity y special grades for use in medical technology R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 77 X E D N I

Materials and Process Engineering 3.6 TECHNICAL THERMOPLASTICS PE: PP: PO –40° 0° +110° +/- ﬂexible – + high TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PO POLYOLEFINS: Polyethylene PE and poly- propylene PP are the most important representatives of the polyolefin class. There are many different grades within both families of materials, the vast majority of which are semi-crystalline. Polyolefins exhibit good wear and friction behavior as well as good insulating properties. They are resistant to many different media, to near- ly all non-polar liquids such as oils, greases and gasoline, but also to water, acids, bas- es and alcohols. They also have very low water absorption, which makes them ide- al for use in the process industry. cable sheathing and other non-conductive components in the electrical industry as well as tubing and fibers for surgical sutures. PP are also mainly used in the packaging industry and in the food and cosmetics sectors. Wastewater pipes are also made of PP, as are housings for small electrical appliances, car body parts (bumpers) and garden furniture. PP fibers are used in moisture-repellent and mite-proof mat- tress covers, but also in clothing, as poly- propylene fabrics are breathable and dry very quickly. PE and PP are the most commonly used thermoplastics in the world with a wide range of everyday applications. Due to their high flexibility, polyolefins are also ideal for sealing, e.g. as screw caps for beverage bottles. The main areas of application for PE are bags and films for packaging, canisters, 78

3. General material selection and descriptions PROPERTIES y thermal application range: PE: –60 °C to +90 °C; PP: –40 °C to +110 °C y excellent wear resistance y very good friction behavior y excellent insulation properties y low water absorption y high media resistance (e.g. to acids, diluted bases, oils and greases); special grades with food and drink- ing water approvals y higher flexibility than other thermo- plastic materials such as PA, POM and PEEK I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 79 X E D N I

Materials and Process Engineering O POM –50° 0° +110° +/- low friction – + medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES POM POLYOXYMETHYLENE: POM is a semi-crys- talline plastic and one of the mechanical- ly highly resilient thermoplastics. Thanks to its rigidity, hardness and strength, combined with excellent dimensional stability up to approx. +80 °C, it can often replace parts made of die-cast metal, brass or aluminum. Due to its high resilience, POM is also frequently used for snap-fit connections and spring elements. Its low water absorption is remarkable. Compared to molded parts made of polyamide, it ensures better dimensional stability even under the influence of moisture. POM is used in a wide range of applications in mechanical engineering and the auto- motive industry: gear wheels, parts of tank caps and pumps, valves, fittings, screws and nuts, but also precision parts for elec- trical engineering are made from POM. POM is also used for door and window handles as well as for zippers, tooth- brushes and children's toys. PROPERTIES y thermal application range: approx. –50 ˚C to +110 °C y excellent friction and wear behavior y low water absorption y high media resistance to many or- ganic solvents, oils, weak acids, bases and alcohols y unstable in strong acids and oxidizing agents y special grades with food and drink- ing water approvals 80

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I O O PK POLYKETONE is a semi-crystalline thermo- plastic. It combines the good sliding and friction properties, low water absorption and excellent hydrolysis resistance of POM with the higher melting temperature of PA6. Polyketones are used in similar appli- cations to POM, e.g. in components and gears for fully automatic coffee machines or in switches and housings in the elec- tronics industry. The high wear resistance and good barrier properties against oxygen and many media PROPERTIES PK –40° +120° 0° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- ﬂexible – + medium R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES as well as its generally good chemical re- sistance allows it to be used in precision parts in the aerospace and automotive industries as well as in shipbuilding and mechanical engineering, in components of fuel systems, for example. PK housings are often provided with an elastomer seal in 2K processes. Polyketone is used in sealing technology, as a hydraulic seal, for example. y thermal application range: approx. –40 ˚C to +120 °C y excellent friction and wear behavior y low water absorption y high media resistance to many organic solvents, oils, acids, weak bases and alcohols. y unlike POM, PK is highly resistant to acids y strong bases can attack PK y special grades with food and drinking water approvals or a flame-retardant finish R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 81 X E D N I

Materials and Process Engineering PA: PA 6.6: N N O O N O PA –40° +130° 0° +/- stiﬀ – + medium TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PA6.6 PA ALIPHATIC POLYAMIDES comprise a large class of different polymers. The most im- portant representatives are PA 6, PA6.6, PA 4.6, PA11 and PA12. Polyamides are tough plastics with high strength and stiffness, excellent impact resistance and good abrasion and wear resistance. PA6, PA11 and PA12 are synthesized from one monomer, where the number indicates the number of carbon atoms between the nitrogen atoms in the main chain. PA6.6 and PA4.6 are produced from two differ- ent monomers, the diamines and the dicarboxylic acids, so that the number of carbon atoms between the nitrogen atoms and the carbonyl functions can differ. PA6, PA6.6 and PA4.6 are mostly used for glass fiber reinforced molded parts; The range of applications is broad and extends from gear wheels to truck oil pans. These polyamides absorb several percent by weight of water under ambient conditions, which must be taken into account when designing components and makes high dimensional stability difficult. PA6 is also processed in large quantities into fibers and textiles. Fishing lines are also made of PA6. PA11 and PA12 absorb much less moisture than the aforementioned types. Due to their high diffusion resistance, they are used as a barrier layer in fuel hoses. In sealing technology, seals made of elas- tomers, liquid silicone (LSR) or TPE are often directly molded onto PA housings using 2K processes, opening up complete- ly new product designs. There are also pneumatic seals made of PA. 82

3. General material selection and descriptions PROPERTIES y thermal application ranges: PA11 and PA12: –70 °C to +110 °C PA6: –40 °C to +130 °C PA6.6: –40 °C to +140 °C PA4.6: –40 °C to +180 °C y high mechanical strength and stiff- ness y very good wear and friction behavior y low creep tendency y very good resistance to lubricants and gasoline, resistant to hydrocar- bons (aliphatic, cyclic and aromatic) y resistant to halogenated solvents and superheated steam y unstable in organic and mineral acids and bases y many special grades, e.g. with flame protection or friction optimization I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 83 X E D N I

Materials and Process Engineering O O O O O PBT POLYBUTYLENE TEREPHTALATE is a semi- crystalline, thermoplastic polyester mate- rial. PBT is characterized by high stiffness and strength, good sliding properties and very low water absorption. This makes it ideal for dimensionally stable housing and structural components and connectors. Typically, grades with medium to high glass fiber contents are used here. Many products made of PBT are used in the automotive and electrical industries. PBT can be given an excellent flame- retardant finish, so that even the high fire PROPERTIES PBT –50° +130° 0° +/- stiﬀ – + medium TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES protection requirements in electric vehicles can be met. Due to its good tribological properties, in particular its good sliding behavior, PBT is also used in moving parts. Types that are suited for drinking water are used in the sanitary sector, in shower heads, for example. In sealing technology, PBT housings are usually overmolded with elastomers or liquid silicone (LSR), thus reducing the assembly effort. y thermal application range of –50 °C to +130 °C y good tribological properties y very low water absorption y resistant to lubricants containing mineral oil and all hydraulic fluids, diluted bases, acids and alcohols y unstable in hot water and strong acids and bases y special grades with approvals for contact with drinking water or flame- retardant types 84

3. General material selection and descriptions 3.7 HIGH-PERFORMANCE THERMOPLASTICS PPS –100° 0° 0° +/- stiﬀ – + +240° medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES flame retardant. The UV and weather stability is low. PPS is available in two structural variants: PPS with purely linear chains has a higher toughness, while PPS grades with branched chains have slightly higher strengths. Due to its excellent mechanical properties, PPS is used as a molded part in demanding applications. Pump housings and lamp bases are made from PPS. The material is frequently used in the electrical and auto- motive sectors, as well as in aerospace and oil production. y poor resistance to hot steam and low resistance in strongly oxidizing media y low UV and weather resistance y inherently flame-retardant S PPS POLYPHENYLENE SULPHID E is a semi- crystalline thermoplastic whose aromatic monomer units are linked to each other via sulphur bridges. At up to 70%, the degree of crystallization is significantly higher than that of most other semi-crystalline plastics. The drop in mechanical properties at the glass transition is therefore lower with PPS than with other thermoplastics. The material is characterized by very good mechanical properties and high heat deflection temperature as well as high chemical resistance and stiffness, is electrically insulating and is naturally PROPERTIES y thermal application range of –100 °C to +240 °C y good tribological properties y very low water absorption y good chemical resistance to alcohols, ketones, aliphatic hydrocarbons, acids and alkalis I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 85 X E D N I

Materials and Process Engineering O O O NR N PPA –40° +180° 0° +/- stiﬀ – + medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PPA PARTIALLY AROMATIC POLYAMIDES, also known as "polyphthalamides" or " partially aromatic polyamides," have an aromatic structural element in their molecular structure, usually benzenedicarboxylic acids; the most important representa- tives are PAMXD6, PA6T/6I, PA 6T/66, PA 10T/X, PA4T, PA9T. PPAs are semi-crystalline, highly temper- ature-resistant and have high glass tran- sition temperatures; this means they have good heat resistance. The materials have high stiffness and tensile strength, good dimensional stability, are creep- resistant and have little tendency to warp. Polyphthalamides have better chemical resistance than standard polyamides and have good corrosion resistance. They can be used in contact with biodiesel, brake fluids, synthetic engine oils, gear and transformer oils and glycols. PPAs are often used as metal substitutes in structural components, often where high heat resistance combined with high mechanical stability is required, e.g. in the engine compartment or in pumps and supply lines. The grades used are usually filled with large quantities of glass or carbon fibers. Due to their low moisture absorption, partially aromatic polyamides are used in sanitary systems, e.g. as housings for thermostats, valve bodies in shower fittings and in electronics as connectors and in household electrical appliances. PPAs are also used in medical technology and in contact with drinking water and foodstuffs, and as carrier parts in taps and shower heads. In sealing technology, PPAs are usually used for housing components onto which elastomer seals are molded. 86

3. General material selection and descriptions PROPERTIES y thermal application range: –100 °C to +180 °C, special grades also higher y high stiffness, high modulus of elas- ticity, creep-resistant, heat-resistant y good wear resistance y lower water absorption than PA6 and PA4.6 y good chemical resistance to a wide range of oils, greases and other hydro- carbons y unstable in acids and alkalis y highly insulating I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 87 X E D N I

Materials and Process Engineering O O N O O O O PEI POLYETHERIMIDES are amorphous high- performance plastics that are characterized by very high stiffness even at high tempera- tures and have very good creep resistance. The mechanical stability of PEI can be significantly increased by adding glass fibers. The material is highly resistant to acidic chemicals, while ketones and chlo- rinated hydrocarbons attack PEI. PEI are highly resistant to high-energy radi- ation and have the highest flame resistance of all non-fluorinated polymers. In normal atmosphere, PEI are non-flammable. PROPERTIES PEI –100° 0° 0° +/- ﬂame-retardant –– + +170° medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES They only start to burn when the oxygen content exceeds 40%. This is why PEI materials are often used in aircraft interiors in the aerospace industry, as smoke gas development in the event of fire is minimal. Because many properties are very constant over a wide range of temperatures and electrical frequencies and PEI materials have high dielectric strength, PEI are used in the electronics industry for coils and fuses. Diaphragms and films are also made from PEI. y thermal application range of –100 °C to +170 °C y adequate tribological properties y high stiffness, good creep resistance y PEI absorbs water, but slightly less than polyamides y good chemical resistance, good hy- drolysis resistance y inherently flame-retardant y highly electrically insulating 88

3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I PEEK –65° 0° 0° O O O O O O R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- wear-resistant – + +260° medium + R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PEEK POLYETHERETHERKETONE is a semi-crys- talline thermoplastic with almost universal chemical resistance to nearly all organic and inorganic chemicals. Exceptions in- clude acidic oxidizing media such as concentrated nitric and sulphuric acid as well as UV radiation in combination with atmospheric oxygen. While the chemical resistance approaches that of PTFE, PEEK shows clearly superior mechanical properties and maximum wear resistance compared to PTFE, which can be further optimized by add- ing various fillers such as glass or carbon fibers. The material can also be processed using conventional injection molding processes. The material is often used in applications with hot water or steam, in steam tur- bines, for example. Due to its high tem- perature resistance and resistance to aggressive chemicals, it is particularly well suited for the process industry. PEEK is also used in engine, compressor and pump components, drives, valves, support and backing rings and many other areas. Some material variants have the relevant approvals for applications in the food and beverage industry. PEEK is also used in medical technology to create permanent implants. PROPERTIES y thermal application range: –65 °C to +260 °C y nearly universal chemical resistance y excellent mechanical strength y highest wear resistance y not resistant to strongly oxidizing chemicals and special solvents y special grades for use in electronic applications and medical technology R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 89 X E D N I

Materials and Process Engineering PVDF: F F ETFE: F F ETFE/PVDF –30° +150° 0° +/- extremely durable – + high TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY CHEMICAL PROPERTIES PVD F has mechanical properties compa- rable to POM and is quite gas-tight. Most other partially fluorinated thermoplastics, including ETFE, have significantly lower stiffnesses and higher elongations. This makes them ideal for sealing technology, but also for membranes and films, which are increasingly being used in architecture. In addition to PVD F and ETFE, there are a number of other partially fluorinated thermoplastics, but most of these are optimized for very specific applications and are not widely used. F F ETFE PVDF The two most important representatives of the polymer class of partially fluori- nated thermoplastics are ETHYLENE TETRAFLUORO ETHYLENE COPOLYMER ETFE and POLY VINYLID E FLUORID E PVDF. Both are semi- crystalline plastics. In con- trast to the most common fluoroplastic PTFE, partially fluorinated thermoplastics can be processed using most thermoplas- tic shaping processes such as injection molding, extrusion or welding. However, processing requires special measures such as the use of acid-resistant steels in contact with the hot thermoplastic melts and sufficient extraction and ventilation. The mechanical properties of the partially fluorinated thermoplastics can be further improved by using fillers such as carbon fibers. 90

3. General material selection and descriptions PROPERTIES y thermal application ranges: PVD F –30 °C to +150 °C y ETF E –100 °C to +150 °C y adequate to good tribological prop- erties y no water absorption y high thermal expansion coefficient limits dimensional stability y very comprehensive chemical resist- ance y not resistant to alkali metals, fluor- inated solvents and specific acids and bases y inherently flame-retardant I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 91 X E D N I

Materials and Process Engineering PFA: FEP: F C F F C F F F F C F F F C O m FC F CF3 F F F n F F PFA FEP The two most important representatives of the polymer class of fully fluorinated thermoplastics are PERFLUOROALKOXY COPOLYMERS PFA (copolymers made of tetrafluoroethylene and perfluoroalkoxy- vinyl ether) and FLUORINATED ETHYLENE- PROPYLENE COPOLYMER FEP (copolymers made of tetrafluoroethylene and hexa- fluoropropylene). Both are semi-crystalline plastics that are largely chemically inert. Just like the partially fluorinated plastics described above, fully fluorinated thermo- plastics can also be processed using most thermoplastic molding processes, although processing requires taking a few special measures. Fully fluorinated thermoplastics are sometimes marketed as "thermoplas- tic PTFE." The designation is appropriate for temperature and chemical resistance. PFA/FEP +/- extremely durable 0° – + –200° +250° high + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES Certain mechanical properties such as flexural fatigue strength or even scratch resistance are significantly lower, however. This is due to the fact that the polymer chains of PTFE are significantly longer. The mechancal properties can be further improved by using fillers such as carbon fibers. Fully fluorinated plastics have significantly lower moduli and higher elongation than non-fluorinated types and are susceptible to high-energy radiation. PFA and FEP are transparent, highly elec- trically insulating and UV-resistant. They are used in a wide range of applications in the aerospace, petrochemical, electronics and semiconductor industries as well as in medical technology and the food industry. 92

3. General material selection and descriptions PROPERTIES y thermal application ranges: PF A –200 °C to +240 °C FEP –200 °C to +200 °C y adequate to good tribological prop- erties y no water absorption y high thermal expansion coefficient restricts dimensional stability y very comprehensive chemical resist- ance, UV-resistant y not resistant to alkali metals, fluor- inated solvents y inherently flame-retardant y many grades are approved for the pharmaceutical and food sectors I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 93 X E D N I

Materials and Process Engineering F F F F PTFE +/- low friction 0° – + –200° +260° high + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PTFE POLYTETRAFLUOROETHYLENE is another fully fluorinated, semi-crystalline plastic. In addition to its complete fluorination, its outstanding properties result from the significantly longer molecular chains compared to other polymers. As a result, PTFE cannot be melted and cannot be processed using classic thermoplastic shaping processes such as injection mold- ing. A semi-finished product is usually produced in a sintering process and then machined into the final geometry. Its property profile is comparable to that of FEP. It is chemically highly resistant; only liquid alkali metals and some fluorine compounds attack PTFE at higher pressures and temperatures. Nothing sticks to the smooth surface of PTFE (anti-adhesive). PTFE is not very resistant to high-energy radiation and is difficult to adhere to. Due to its high cold flow and low resistance to abrasion and wear, pure PTFE is only used in sealing technology for low requirements. PTFE mixtures with special fillers are used for high-performance seals. The most im- portant fillers include bronze and steel, glass fibers, glass beads, carbon fiber, graphite, ceramic fillers and solid lubricants such as molybdenum sulfide. PTFE materials are indispensable in nearly all areas of industry. PTFE applications include mechanical engineering, the chemical industry and plant construction, electrical and semiconductor technology, the pharmaceutical and food industries as well as medical and analytical tech- nology. 94

3. General material selection and descriptions PROPERTIES y thermal application range: approx. –200 °C to +260 °C y nearly universal chemical resistance y best electrical insulation values and good dielectric properties y resistant to light and weathering y no ageing y physiologically harmless in the range up to +200 °C y very good sliding properties, no "stick-slip" effect y self-lubricating, so that bearings and motion seals can also run dry under certain conditions y anti-adhesive behavior y non-flammable y no water absorption y grades with food and drinking water approval are available I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 95 X E D N I

Materials and Process Engineering O N O N O O O O PAI –100° 0° 0° +/- wear-resistant – + +260° medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PAI POLYAMIDE-IMID E is an amorphous ther- moplastic that has various aromatic structural units in the polymer chain, making it one of the most thermally sta- ble polymers with a carbon backbone. After molding, articles made of PAI must be cross-linked in a complex 17-day tem- pering process. Only this thermal post-treatment gives the products their unique mechanical properties, which are retained at temperatures of up to +260 °C. In addition to a high degree of tensile and compressive strength, PAI exhibits low thermal expansion, which enables very dimensionally stable components. There are friction and wear-optimized grades that can be used at temperatures up to +275 °C, as well as grades with glass and carbon fibers for optimized stiffness and strength. These properties, together with the in- herent flame retardancy, make PAI the ideal choice for many applications in the aerospace industry and in power plant technology. Highly heat-resistant coatings are also made from PAI. Applications can also be found in the automotive industry for extreme tribo- logical requirements such as rectangular sealing rings and thrust washers. PROPERTIES y thermal application range –100 °C to +260 °C y high compressive strength and creep resistance y excellent tribological properties y good chemical resistance y susceptible to hydrolysis at higher temperatures y inherently flame-retardant 96

3. General material selection and descriptions 3.8 DUROMERS Duromers are highly cross-linked materials that neither soften nor melt in the heat. After curing, they are more dimensionally stable than non-cross-linked plastics. Duromers have the lowest tendency to creep and the highest strength of all poly- mer materials. They are particularly attrac- tive for structural applications because their thermal expansion is in the same order of magnitude as that of steel and aluminum, and can be adjusted within limits. Due to their brittleness, duromers are often filled with fibers. For example, short and long fibers (BMC), continuous fibers (SMC) and resin-impregnated fabrics and scrims (prepregs) are used. The type of fiber reinforcement determines what processing methods are possible. Most duromer components are manufac- tured using compression molding (SMC, prepregs). However, granulates suited for injection molding (BMC) are also increas- ingly available. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 97 X E D N I

Materials and Process Engineering CH2 N CH2 N CH2 N CH2 N C=O C=O N CH2 N CH2 N CH2 N CH2 C=O C=O UF Urea-formaldehyde resins are among the oldest class of industrially used duromers, the aminoplastics. The oligomers (some- times polymers) are produced by a con- densation reaction of methylol ureas with urea. The cross-linking is acid-catalyzed (with latent curing catalysts). The thermal application range is rather restricted at +80 °C for continuous use. UF resins are characterized by good color- ability and lightfastness. They are also highly scratch-resistant and very cost-ef- fective. Like most duromers, UF resins are quite brittle and stiff. UF resins are resistant to organic solvents, greases and oils as well as cold water. UF resins are not resistant to hydrolysis and UF +80° +/- colorfast 0° – + –200° low + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MATERIAL PROPERTIES are therefore not suited for even weak acids and bases, or for hot water. In addi- tion, they are prone to stress cracking due to high shrinkage. UF resins are widely used in the wood and furniture industry, for door and wall cov- erings as well as for decorative laminate, pressed and façade panels, for example. They are also used in textile finishing and as a binder for paper. PROPERTIES y thermal application range: –200 °C to y unresistant to acids and bases, un- +80 °C y cost-effective y good weather and light resistance y resistant to many solvents, oils and greases, as well as cold water suited for hot water applications y high gloss, high scratch resistance y brittle 98

3. General material selection and descriptions O O O O O O O CH2 CH2 O O CH2 CH2 O O C C O CH CH CH CH O C C O CH3 O CH2 CH O O CH2 CH O CH3 UP UNSATURATED POLYESTER RESINS are produced in two steps. First, unsaturated linear polyester resins are produced by polycondensation of unsaturated dicar- boxylic acids or their anhydrides with diols. These are then cross-linked in the second step with vinyl-containing monomers such as styrene or methacrylic acid methyl ester in radical copolymerization. The thermal resistance depends on the monomers used and is higher the more aromatic monomers are used. UP is char- acterized by good resistance to hydro- carbons, but is susceptible to hydrolysis. Unsaturated polyester resins are inex- pensive and often show lower shrinkage UP 0° 0° +/- good electrical Insulation – + –200° +185° low + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY MECHANICAL PROPERTIES and better dimensional stability due to lower water absorption. UP resins are used to make heating oil tanks and pipes, as well as furniture, car body parts, caravans and molded parts with electrically insulating proper- ties such as distribution boxes, plug connectors and housings for household appliances. PROPERTIES y the thermal application range is high- ly dependent on grades: –270 °C to +100 °C; special grades up to +185 °C y cost-effective y resistant to mineral oil, benzene, greases and hydrocarbons y good insulation properties y suited for contact with food y good colorability y brittle, low elasticity y poor resistance to acids, bases, hot water, ketones and halogenated hydro carbons I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 99 X E D N I

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Materials and Process Engineering N O R[ O ] n HO HO HO HO N O R[ O ] n N O R O N HO HO N n OH HO N O R[ O ] n O R[ O ] n HO HO EP EPOXY RESINS are usually oligomeric di-glycidyl ethers of bisphenol A, which are functionalized by a reaction with epichlorohydrin with a different number of epoxy groups per molecular chain. The cross-linking of these epoxy groups is then carried out with amine hardeners. A distinction is made between cold curing (aliphatic amines) and hot curing (aro- matic amines), as the type of curing also determines the maximum application temperature. Epoxy resins are classified as duromers since their properties can be adjusted very variably. On the one hand, many dif- ferent monomers and cross-linkers are available to create a specific structure. On the other hand, the functionality of the building blocks and therefore also the re- sulting cross-linking density can be con- trolled quite easily. PROPERTIES y thermal application range: –40 °C to +80 °C (cold curing), or +170 °C (hot curing), special grades up to +200 °C y wide range of properties y cold and hot cross-linking y suited for food contact y high elasticity (for duromers) N N EP +/- ﬂexible 0° – + –200° +170° medium + TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES This means that EP duromers can also be produced with comparatively high elas- ticities. The main applications of epoxy resins are components for electric motors, insulators and capacitors, paints and chemical- resistant floors. Rotor blades for wind tur- bines and helicopters as well as boat hulls are also made from EP resins. In addition, they are often the basis for printed circuits, pipelines, containers, pump components and adhesives for rubber-metal compos- ites. y good resistance to organic solvents, mineral oil, gasoline and water y low shrinkage, good heat resistance y low resistance to strong acids, bases and oxidizing agents 100

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3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I OH PF –30° R O F S L A E S Y R A T O R S N O T A C I I L P P A +/- abrasion-resistant 0° – + +250° high + R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H n TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES PF PHENOL-FORMALDEHYD E RESINS The reaction of phenol with formaldehyde produces resinous condensation products. A distinction is made between Novolake (amine-cross-linking) and Resole (self-cross- linking). DIN-typed compounds differ in terms of various fillers and reinforcing agents and their contents. Like all duromers, phenolic resins have high hard- ness and strength and are flame-retardant. In addition to their good media resistance, phenolic resins also have high abrasion re- sistance. The continuous operating tem- perature can be up to +250 °C. Tempered parts can even be exposed to temperatures of up to +300 °C for short periods. PROPERTIES y thermal application range: –30 °C to +250 °C y high hardness and strength y low creep tendency y flame-retardant y high pressure resistance y yellow to brown coloration, darkening in use (light, heat) PF resins are used to make sockets, switch housings, lamp sockets, bearings and pump parts. They are also suited for manu facturing all kinds of handles, e.g. for pots and pans, irons and barbecues; as well as for billiard balls, gear wheels, binders for brake disk friction linings and as an adhesive agent in the manufacture of rubber-metal composites. In the field of sealing technology, PF resins are used in tribologically challenging applications, such as gearbox thrust washers, piston rings for hydraulic seals and other wear protection rings, as well as seals for intake manifolds or in brake cylinders. y brittle, notch-sensitive y not for contact with food y resistant to organic solvents, acids, alkaline and salt solutions y low elasticity and tensile strength y not resistant to strong acids and bases R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 101 X E D N I

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Materials and Process Engineering PI +/- low friction 0° – + –270° +260° high n TEMPERATURE RANGE (°C) MEDIA COMPATIBILITY DYNAMIC PROPERTIES and the radiation resistance of polyimides are excellent. The materials are largely resistant to solvents, greases, fuels, oils and acids. Only strong bases can attack polyimides. Polyimides are used to manufacture en- gine and compressor parts, aircraft parts, high-quality cable and wire sheathing, circuit boards and valve seats as well as fibers for fireproof protective suits. In sealing technology, the focus is on tri- bological applications: gearbox thrust washers, sealing applications for the aerospace industry, piston rings and other wear protection rings. y flame-retardant y strong bases can attack polyimides y high price y very hard and brittle O N O O N O O PI POLYIMIDES The starting materials for polyimides are bismaleimide or other tetracarboxylic acid anhydrides. From these, duromeric polyimides with different molecular structures are formed by poly- condensation with diamines. A common feature of these heterocyclic polymers is the very stable imide ring within the main chain. Polyimide components are charac- terized by high temperature resistance up to over +260 °C, in the short term also up to over +300 °C, while largely retaining their mechanical properties. The materials are also characterized by good sliding and wear properties, which can be further improved by adding appro- priate additives. The electrical properties PROPERTIES y thermal application range: –270 °C to +260 °C (briefly above +300 °C) y high hardness and strength y good sliding and wear properties y very resistant to solvents, greases, fuels, oils and acids y high radiation resistance 102

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3. General material selection and descriptions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I In addition, Freudenberg's internal safety standards, which often go far beyond the legal requirements, particularly in the area of environmental protection and occupational safety, encourage the development teams to find ever more sustainable solutions. In particular, the use of raw materials in our formulations that are harmful to health or potentially hazardous to the environment is subject to strict internal safety standards. The continuous adaptation and further development of our materials portfolio is only possible under three conditions: y a large team of well-trained and expe- rienced materials developers and pro- cess engineers y in-house laboratories with comprehen- sive testing expertise y well-equipped pilot plants for constant monitoring and optimization of the processing behavior of the materials 3.9 COMPOSITION OF FST MATERIAL DESIGNATIONS Freudenberg Sealing Technologies uses standardized material designations for its elastic materials. 70 75 EPD M FKM 120209 585 Hardness (Shore A) Rubber designation Mixture number y Hardness: The prefix indicates the hardness of the material in Shore A y Rubber designation: The base rubber according to standard ISO 1629:1995 is named in second place y Mixture number: The number after the rubber designation is an internal FST code that can contain 3 to 6 digits and codes the formulation 3.10 VARIETY OF MATERIALS As a global market and technology leader in sealing technology, FST serves the needs of its customers with a portfolio of over 1,300 different materials made from 1,000 different raw materials. Every year, newly developed formulations are added to the portfolio, while out- dated formulations are abandoned. Our continuous efforts at product devel- opment serve and respond to the constant- ly growing demands of our customers, the ever more stringent requirements of chemicals legislation and the changing availability of raw materials. R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Map-Marker-Exclamation Adaptation and further development of materials S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 103 X E D N I

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Materials and Process Engineering 4. UNDERSTANDING ELASTOMER FORMULATIONS Everything starts with the formulation – whether it’s a standard elastomer for a wide range of applications or specially designed compounds. This chapter exam- ines in detail the raw materials used and which properties of an elastomer they influence. FORMULATION INGREDIENTS The rubber industry uses a variety of raw materials that differ significantly in terms of their composition: rubber in bale, chip or pellet form is used along with other solids – usually in the form of powders, granules or pellets – and liquids. As confusing as a formulation may seem at first glance, its ingredients can be summarized into seven main groups of raw materials. Raw material rebbuR 1 relliF 2 relliF rezicitsalP Processing aid Anti-ageing agent 1 Anti-ageing agent 2 Vulcanization media ruhpluS rotareleccA Co-accelerator Activator zinc oxide Activator stearic acid Vulcanization retarder tnemgiP Total phr 001 03 51 01 1.5 2 2 1 3 1.5 4 2 1 3 176 Weight % 28.65 50.71 25.8 86.5 0.85 1.14 1.14 75.0 07.1 0.85 2.27 1.14 0.57 07.1 100 Fig. 10 Example of a rubber compound with sulphur cross-linking 104 7 Raw material groups of a formulation 1. Rubber 2. Fillers 3. Plasticizers 4. Anti-ageing agents 5. Processing aids 6. Vulcanization media • Cross-linkers • Accelerators • Activators • Retarders • Coagents 7. Special additives When selecting the raw materials for a rub- ber compound, it is important to consider not only the desired final properties of the elastomer but also the storage stability of the compound and its processability. Not every formulation necessarily contains all seven raw material groups. The quantities of raw materials used in a formulation are specified in the unit phr (=parts per hundred rubber). Phr denotes the mass fractions of theindividual raw materials in the formulation. They are always specified in terms of 100 parts by the mass of rubber. The advantage of the phr unit compared to a quantity in percent by weight is that the differences between formulations can be recognized at a glance when com- paring them. → Fig. 10 shows a general example of a formulation.

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4. Understanding Elastomer Formulations Different raw materials are used in very different quantities. The variety of raw materials used, the different proportions in the formulation and their different physical delivery forms place high demands on the mixing technology (see also → “7.2 Mixture production”, page 126). RUBBER The most important properties of an elastic material are its temperature limits and chemical resistance: both are largely determined by the rubber. The other properties can be varied in many ways through the appropriate selection and clever combination of all other com- pound components and can be tailored to the respective application. The following general questions should be asked in order to find the most suitable rubber for the application: y what media does the material come into contact with? y in what temperature range is the material used? y what are the ambient conditions? These can be varied – from direct sun- light to pressure and sea air y what mechanical stresses does the material experience? Strong defor- mation, dynamic stress or stress due to wear The most important rubber classes and their property profiles are described in → “3.3 All-purpose Rubbers”, page 50, und “3.4 Speciality Rubbers”, page 54. FILLERS Fillers are solid, usually particulate, some- times also platelet or fibrous solids in the size range between 10 nm and 500 µm. Contrary to what the word "filler" sug- gests, this class of material is not usually used to increase the volume of the com- pound at low cost. Rather, the targeted use of fillers can influence and optimize important properties of an elastomer such as hardness, stiffness, tensile strength and tear resistance, maximum elongation or wear. Special fillers are also used to influence the thermal or electrical conductivity or the fire behavior of elastomers, or to make the materials magnetic or magnetizable. The vast majority of rubbers do not ex- hibit sufficient tear and tensile strength if fillers are not used. Common filler classes used to reinforce elastomers are carbon blacks, mineral fillers such as chalk, silica, kaolin and talc as well as synthetic silicic acids and a range of metal oxides, sulphates and hydrox- ides. More and more fillers such as cellu- loses, lignins or carbon blacks obtained from used tires are now also being put to use. MEDIA STRESS Fillers are mainly described based on the following parameters: TEMPERATURE ENVIRONMENT y specific surface area y geometric structure y chemical nature of the surface I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 105 X E D N I

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Materials and Process Engineering Depending on the particle size and there- fore the specific surface area, a distinction is made between active (reinforcing) and in- active (non-reinforcing) fillers. The particle diameters of reinforcing fillers are between 10 and 100 nm, while inactive fillers have particle diameters between 500 and 1000 nm. In any case, the prerequisite for optimal properties of the rubber compounds is the most uniform possible distribution of the fillers as well as good dispersion (see also → “7.2 Mixture production”, page 126). Reinforcing fillers interact strongly with the rubber matrix. As a result, this filler class significantly influences the properties of the rubber compound and the vulcanizate. Reinforcing fillers increase the viscosity of the rubber compounds and the hard- ness of the vulcanizates. They improve the strength and abrasion behavior of the vulcanizates. There is an optimal filler dosage for each of these properties, i.e. these properties deteriorate again with high filler quantities. → Fig. 11 shows that certain properties cannot be opti- mized independently of each other. Inactive fillers have little or no reinforcing effect. In order to understand how the reinforcing effect of fillers (FS) in rubbers (R) works, four forces must be considered, which are of very different magnitudes and interact with each other: Internal cohesion of the FS particles >> Adsorption forces FS – R > Interaction forces R – R > Interaction forces FS particles – FS particles The rubber molecules attach to the sur- face of the filler particles during the mix- ing process (→ Fig. 12). The resulting adsorption forces contribute to the strength, which initially increases as the filler content rises. If a certain degree of filling is exceeded, there are no longer enough rubber molecules to adhere to the filler particles, and direct contact between filler particles increasingly occurs. As these interaction forces are much lower than those between rubber molecules and filler particles, the strength decreases again at high filler dosages. Properties such as viscosity or hardness, on the other hand, increase steadily as the amount of filler increases. This is due to the fact that solid particles are many times y t i s o c s V i s s e n d r a H i e c n a t s s e r r a e T i n o s a r b A Filler quantity Filler quantity Filler quantity Filler quantity reinforcing inactive Fig. 11 Influence of active and inactive fillers in elastomers 106

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4. Understanding Elastomer Formulations Fillers whose surfaces are designed to chemically bind to the rubber molecules during vulcanization enable special prop- erty profiles of the rubber compounds: above all, a good combination of strength, abrasion, wear and elasticity. Map-marker-edit Special property profiles of the rubber compounds I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P PLASTICIZERS Plasticizers are liquids, greases or resins that are added to rubber mixtures for various reasons. There are advantages both in the processing of the rubber mixture and in the properties of the vulcanizate. y As a processing aid Plasticizers reduce the viscosity of the mixture and make the rubber com- pounds easier to process y To increase the filling level The use of plasticizers enables high filler dosages. Rubber compounds with large quantities of fillers are very viscous and therefore usually difficult to mix and pro- cess. The addition of plasticizers lowers the viscosity and allows the use of larger quantities of fillers while maintaining good filler distribution and dispersion. y To reduce the stiffness and hardness of the vulcanizate As the word "plasticizer" suggests, plasticizers reduce hardness and stiff- ness; at the same time, they increase the elongation of the vulcanizate H O H O Si Si Si Si SiSi H H O O CH3 CH3 Si CH3 O H O Si Si Si Si SiSi S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B CH3 Si O O CH3 S M G A R H P A D I X O B G N I F F U T S I S G N K C A P O H O H O H O CH3 Si CH3 CH3 Fig. 13 Hydrophilic and modified hydrophobic silica surface 107 X E D N I Fig. 12 Polymer chains attached to a filler particle stiffer than rubbers. The higher their pro- portion in the rubber, the more viscous the mixture becomes and the stiffer and hard- er the vulcanizate becomes. The chemical nature of the surface of fill- er particles also has a major influence on the mixing properties. It determines how well the filler particles can be mixed into a rubber and how strong the adsorption forces are between the rubber molecules and filler particles. Fillers with a strongly polar, hydrophilic (water-loving) surface such as silicic acids are more compatible with polar rubbers and tend to be more difficult to mix in be- cause the interaction forces between FS particles and FS particles are very high. High strengths can be achieved with such fillers, but the elastic recovery behavior is often not optimal. Fillers with a non-polar, hydrophobic (water dissimilar) surface such as carbon blacks or chemically modified (hydropho- bized) silicas exhibit weaker interaction forces between the FS particles. They are therefore easier to mix in, have less influ- ence on the viscosity of the mixture and enable materials with high elasticity.

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Materials and Process Engineering Fig. 14 Rubber matrix with filler particles (left) and mixed-in primary plasticizer (right) y To improve low-temperature flexibility By adding appropriate plasticizers, the glass transition temperature of the vul- canizate can be lowered and thus the minimum application temperature can be shifted to lower temperatures The addition of plasticizers causes various properties of a vulcanizate to change simul- taneously. For example, plasticizers can be used to improve flexibility at low tempera- tures, but this often also leads to a deteri- oration in resistance to hot air. The mode of action of plasticizers can be divided into two groups: y Primary plasticizers (→ Fig. 14) This type of plasticizer is very similar in its molecular structure to the rubber used, which is why the plasticizer mixes very well with the rubber. Individual plasticizer molecules attach them- selves to the polymer chains, which considerably improves the mobility of the polymer chains. This results in a significant reduction in the viscosity of the mixture as well as improved low-temperature flexibility and re- duced stiffness The combination of EPD M with paraffinic mineral oils is one example. The rubber and plasticizer molecules differ considerably in size. However, they are chemically very similar and can therefore be easily mixed with each other y Secondary plasticizers (→ Fig. 15) This type of plasticizer differs so much in terms of its chemical structure and polarity from rubber that it mixes with the rubber only with difficulty and therefore cannot be absorbed by the rubber matrix, or only in small quanti- ties. Secondary plasticizers act like inter- nal lubricants. They have hardly any in- fluence on the viscosity, tend to sweat out due to their low rubber compatibil- ity. This effect depends on time and temperature: After the compound has cooled down, the plasticizer may sweat out, as the amount of secondary plasti- cizer that the rubber compound can ab- sorb decreases rapidly as the tempera- ture drops. This effect can significantly facilitate the demolding of the vulcani- zate from the mold One example is the use of paraffinic mineral oils in oil-resistant NBR rubbers The most common plasticizers can be found in the following list: 108

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4. Understanding Elastomer Formulations MINERAL OIL PLASTICIZERS (CRUDE OIL REFINING) NATURAL SUBSTANCES AND MODIFIED NATURAL SUBSTANCES SYNTHETIC PLASTICIZERS y paraffinic y naphthenic y aromatic y highly aromatic y fatty acids y fatty acid esters y wool grease (lanolin) y vegetable oils y resins y factice y Ester plasticizer y Ether plasticizer y Thioether ester y Polyether, Polythioether y Polyester y Chlorinated hydrocarbons PROCESSING AIDS Processing aids are a class of chemicals that are added to rubber compounds in small quantities to improve processability. Their use is often closely linked to a special pro- cessing or molding process. In addition to improving the flow behavior or wall slip, processing aids are also used to reduce or increase the stickiness of the raw com- pounds and to improve demolding. Processing aids that improve the flow behavior act similarly to secondary plas- ticizers, but their lubricating effect is par- ticularly pronounced. Even at a very low proportion in the compound, they ensure that the rubber chains slide against each other, which often significantly improves not only the flow but also the demolding behavior of the compound. These chem- icals are used when rubber compounds need to flow very well, especially when molding in the injection molding process. Processes with long flow paths, filigree distributors and those in which the tem- peratures remain low during flow, such as in cold runner technology, place particu- lar demands on the flow behavior (see also → “7.3 Shaping and vulcanization”, page 130). ANTI-AGEING AGENTS The rubbers used in the rubber industry are organic molecules that essentially consist of the atoms carbon, hydrogen, oxygen and nitrogen. Some rubbers also contain silicon, chlorine or fluorine atoms and in some cases, sul- phur is also added during vulcanization. The chemical bonds between these atoms vary in terms of stability, with the least stable bond determining the life of the vulcanizate. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 15 Rubber matrix with filler particles (left) and an attached secondary plasticizer (right) 109 X E D N I

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Materials and Process Engineering Rubber molecules age at different rates and to different degrees; the least resist- ant to ageing are R-rubbers with many double bonds and sulphur-cross-linked vulcanizates. The maximum application temperatures shown in → Fig. 16 provide an initial indication of the ageing resist- ance. The shaded areas indicate temper- ature ranges to which standard grades can only be exposed for a short time or that can only be reached by special grades. The term “ageing” covers a large number of physical and chemical processes that irre versibly change the material proper- ties and which occur under the influence of oxygen, ozone, UV light, temperature, hot water, steam, acids, alkalis or other media as well as under mechanical stress. Ageing can have different effects on dif- ferent elas tomers: Ageing effects depend on the type of change in the polymer network and can be divided into three groups: y chain dismantling y reduction of cross-linking points y additional cross-linking As shown schematically in → Fig. 17, age- ing can lead to a breakdown of polymer chains or cross-linking points. As a result, hardness, stiffness and elasticity decrease and elongation increases. On the other hand, ageing can also gen- erate additional cross-linking points; in this case, hardness, stiffness and elastic- ity increase, while elongation decreases significantly. The mechanisms of ageing are complex and in many cases not fully understood. Several effects often overlap. Ageing vulcanizates can first soften and then harden and become brittle after pro- longed ageing or at higher temperatures. The higher the application temperatures, the faster the vulcanizates age. As a first rule, one can say that an increase in tem- perature by +10 °C accelerates ageing by a factor of 2 (Arrhenius law). The ageing of organic materials cannot be prevented, but it can be significantly delayed by using the right chemicals (anti- ageing agents). The anti-ageing agents are used up over time and their protective effect diminishes. Two modes of action of anti-ageing agents are explained briefly below: y Surface protection Paraffin waxes have the property of migrating to the surface of the vulcan- izate and forming a protective film there. Paraffins are hydrocarbons without double bonds and effectively protect rubber from ozone attack. In particular, rubbers with double bonds in the main chain benefit from this built-in “sun cream” protection. y Protection against ageing due to oxygen and heat (thermo-oxidative ageing) Oxygen is one of the media that can attack and destroy rubber molecules. When oxygen reacts with a rubber molecule, highly reactive radicals are formed that can attack and damage other molecules in a chain reaction. To prevent this, anti-ageing agents are added, which are attacked instead of the polymer network and thus inter- cept the radical attack. 110

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4. Understanding Elastomer Formulations s r e b b u R AU FFKM PVMQ FVMQ VMQ FKM AEM ACM HNBR ECO IIR/CIIR NBR EPDM CR SBR NR –100 –50 0 +50 +100 +150 +200 +250 +300 Temperature [°C] Fig. 16 Temperature application limits of the most important rubbers The use of anti-ageing agents must be adapted to the base rubber, the other components of the formulation and the subsequent use of the elastomer. For the best possible protection, two or three anti-ageing agents are often combined to provide a synergistic effect, especially in the case of R rubbers that are not highly resistant to ageing. CROSS-LINKING SYSTEM The topic of cross-linking is covered in detail in → “5. Cross-linking chemistry”, page 114. Therefore, the most impor- tant substance classes that belong to the most common cross-linking systems are described only briefly below. Cross-linking agents Cross-linking agents are chemicals that form covalent bonds, so-called cross- linking bridges, between the individual rubber molecules. These include elemental sulphur, sulphur donors and peroxides. Accelerators Sulphur alone only reacts very slowly with the rubber molecules, even at high temperatures. Although vulcanization with pure sulphur at +150 °C takes sever- al hours, the cross-linking remains incom- plete and the elastomers produced in this way have only a moderate property pro- file and age quickly. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 111 X E D N I

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Materials and Process Engineering Cross-linked polymer chains + Attacking medium (e.g. oxygen, oil, water, ozone, UV light ...) Chain degradation (loss of tension) Additional cross-linking (increase in tension) Reduction of cross-linking points (loss of tension) Polymer molecule (rubber molecule) Cross-linking points Fig. 17 Aging of elastomers Accelerator chemicals are added to reduce reaction times, temperatures and the amount of sulphur required. Common rep- resentatives of this substance class are or- ganic compounds that contain nitrogen or sulphur, such as benzothiazoles, benzothi- azole sulfenic amides, dithiocarbamates, guanidines or amines, which are used in- dividually or in combination. Activators Metal oxides and fatty acids are used to improve the effectiveness of the acceler- ators. The most common is the combina- tion of zinc oxide and stearic acid. Vulcanization retarders Retarders are sometimes used in sulphur- based vulcanization systems, especially for thick-walled components or in manu- facturing processes with long flow paths. These chemicals delay the vulcanization, i.e. they extend the time until the start of the cross-linking reaction (scorch time) without significantly affecting the over- all speed of the reaction. Organic acids such as benzoic acid, salicylic acid and phthalic anhydride are often used, which have a retarding effect by lowering the p H value. Coagencia If rubber compounds are peroxide cross- linked, coagents are often used in addition to the peroxide cross-linking agent. These chemicals increase the cross-linking den- sity, and some members of the substance class additionally accelerate vulcanization. The use of coagents often allows the amount of peroxide used to be reduced and the vulcanizates exhibit higher elasticity. Coagents have at least 2 active double bonds, typical representatives are triallyl- cyanurate, trialyl isocyanurate, di- or tri- functional acrylates and methacrylates as well as short-chain 1.2-polybutadienes. 112

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4. Understanding Elastomer Formulations ADDITIONAL ADDITIVES Other chemicals can be used in special applications. y Color pigments if colored elastomers are needed, light-colored fillers are used and appro- priate color pigments are mixed in y Blowing agents for the production of foamed rubber or sponge rubber, blowing agents tailored to the respective cross-linking system are added to the rubber mixtures, which release a gas during vulcanization that produces the foam structures y Fire protection additives most rubbers are flammable. For fire protection applications, special addi- tives are therefore mixed into the rub- ber compounds so that the elastomer self-extinguishes even in direct contact with a flame, i.e. neither continues to burn nor afterglow I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 113 X E D N I

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Materials and Process Engineering 5. CROSS-LINKING CHEMISTRY Anyone familiar with the history of rubber knows that the decisive step was not taken until 1839 with the discovery of vulcanization by Charles Goodyear. Be- fore that, natural rubber was certainly a useful material in many respects, but its properties had little in common with those of a vulcanized elastomer. Unvulcanized rubber compounds are plastically deformable and flow under pressure. It is only through the chemical reactions that take place during vulcani- zation that a rubber compound becomes a cross-linked elastomer with high dimen- sional stability and elastic properties. unvulcanized vulcanized rubber Fig. 18 Cross-linking points due to vulcan- ization As can be seen in → Fig. 19, uncured rubber compounds also exhibit elastic material behavior to a small extent, al- though the plastic component always clearly predominates. In the same way, vulcanized rubbers, which behave mainly elastically, also show plastic material be- havior to a small extent, depending on the degree of cross-linking, the polymer and the rest of the formulation. Modern manufacturing processes require close coordination between the formula- tion and the manufacturing process. The composition of the compound and, in particular, the type and quantity of cross-linking chemicals must be selected in such a way that the rubber article can be reliably produced in the selected manufacturing process and has the de- sired end properties. CROSS-LINKING DENSITY The number of chemical bonds formed between the polymer chains during rub- ber, but primarily depends on the amount of cross-linking chemicals used and is called the degree of cross-linking or cross-linking density. before with deformation after deformation before with deformation after deformation unvulcanized rubber vulcanized rubber Fig. 19 Behavior during deformation (difference between unvulcanized and vulcanized rubber) 114

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s e i t r e p o r p Tear propagation Fatigue i t e a z n a c u V l 5. Cross-linking chemistry Elasticity Hardness Stiffness (modulus of elasticity) Tensile strength Hysteresis, damping Permanent deformation Coefficient of friction Elongation at break Cross-linking density Fig. 20 Influence of cross-link density on elastomer properties The cross-linking density also depends on the temperature and the duration of vulcanization and has a major impact on the material properties (→ Fig. 20). Stiff- ness (modulus of elasticity), hardness and elasticity increasing cross-linking density, while elongation at break, damping and permanent defor- mation decrease. Tear propagation resist- ance and tensile strength each reach a maximum. increase with As can be seen from → Fig. 20, it is not possible to achieve an optimal result for all material properties by selecting a specific cross-linking density. The degree of cross-linking is always selected in such a way that the best possible compromise of physical properties is achieved for the respective application. CROSS-LINKING CHARACTERISTICS The course of the cross-linking reaction can be determined using vulcometry. In a special rheometer, the change in the stiff- ness of a rubber compound is measured over time at a constant temperature. The sample is oscillated between two plates at a fixed frequency and the change in torque, which is proportional to the degree of cross-linking, is recorded as a function of time. Typical vulcameter curves are shown schematically in → Fig. 21. There are three characteristic segments of the curve (→ Fig. 21) 1. The flow period covers the time interval from the start of the measurement to the start of cross-linking, i.e. until the torque increases. It characterizes the range of viscous flow. Initially, the torque decreases due to the heating of the rubber compound. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 115 X E D N I

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Materials and Process Engineering The period until the cross-linking reac- tion starts is known as the incubation time. During this time, the mold filling of the tool must be completed. 2. The torque increases significantly during the cross-linking period. This time is re- quired to convert the rubber compound into the optimal cross-linked state. The slope of the curve depends heavily on the type of rubber and the cross-linking chemicals used. 3. Cross-linking is complete when the torque has reached its final value. All chemical reactions are now complete. Curves are also sometimes observed in which the torque reaches a maximum and then decreases again (reversion) or where the torque continues to increase steadily (marching modulus). Every rubber compound shows its own typical curve; the vulcameter curve thus represents a kind of fingerprint of the cross-linking behavior of each rubber compound. The appropriate choice of cross-linking chemicals is used to adjust the cross-linking characteristics of a rubber compound and adapt it to the processing method. This ensures the quality and eco- nomic manufacturability of the rubber components. In addition to development of the formu- lation, vulcanization tests are mainly used for incoming goods inspection and for release testing of rubber compounds. Flow period Cross-linking period T = const ] m N [ e u q r o T 1,0 0,8 0,6 0,4 0,2 0 0 1 2 3 4 5 6 Time [min] Fig. 21 Typical volcameter curves for measuring the cross-linking process 116

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5. Cross-linking chemistry OPTIMIZATION OF ELASTOMER PROCESSING For robust process control to produce flawless rubber articles with as little waste as possible, the flow behavior of the rubber compound must be taken into account in addition to the cross-linking characteristics (cross-linking kinetics). This is because it is not only knowledge of the speed of the cross-linking reaction that is of importance in the molding process, but also how quickly the mold can be filled. In the end, both properties – flow behav- iour and cross-linking characteristics – to- gether significantly determine the overall cycle time, i.e. the time in which the mold can be filled, the rubber compound vulcan- ized and the finished component removed from the mold. The targeted coordination of both parameters with each other and with the manufacturing process allows both material savings by reducing waste and energy savings through shorter heat- ing times and thus a cost-effective produc- tion of the elastomer molded part. The complex relationships between mold filling and vulcanization can be calculat- ed and optimized with the help of filling simulation. Even during the development phase of a rubber compound for a specific application, flow velocities and tempera- ture distributions can be simulated on the computer and the influences quantified. Processing errors such as air inclusions or premature scorching are thus detected at an early stage and avoided by adjust- ing the composition of the formulation or the processing procedure. This reduces the development effort con- siderably. COMPATIBILITY OF THE CROSS-LINKING CHEMICALS It should be noted that not every type of rubber can be vulcanized with every type of cross-linking chemistry. For example, cross-linking with sulphur only works with rubbers that contain double bonds. The active sites for sulphur cross-linking are the hydrogen atoms on the carbon atom next to the double bond, the hydrogen atoms in the allylic position. Some types of cross-linking can only be used if the rubber molecules contain special functional groups. These are al- ready created during the synthesis of the rubber by polymerization of special cure- site monomers. CROSS-LINKING AGENTS The cross-linking system determines the processing behavior of the rubber com- pound as well as the chemical structure of the polymer network and thus the physical properties of the elastomers. Many classes of rubber can be cross-linked in several ways. The manufacturing process and the desired property profile of the elastomer compo- nent must be taken into account when se- lecting the best suited cross-linking system. The two most common types of cross-link- ing are cross-linking with sulphur and with peroxides, both of which are described in more detail in the following chapters. Sulphur cross-linking is primarily used in the class of diene rubbers. (R rubbers) are used, and peroxides can also be used to cross-link rubbers without double bonds. There are also various other types of rubber cross-linking, most of which have been developed specifically for certain classes of rubber. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 117 X E D N I

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Materials and Process Engineering The cross-linking points in vulcanized elastomers are usually 30 to 100 monomer units apart. An overview of the possible types of cross-linking chemistry of the most com- mon rubbers can be found in → Tab. 5, page 122. 5.1 CROSS-LINKING WITH SULFUR Elemental sulphur or sulphur donors are used for sulphur cross-linking. Sulphur donors are molecules that release sulphur at high temperatures. Cross-link node structures As already mentioned, cross-linking with sulphur works with all rubber classes that have a sufficient number of C=C double bonds and whose structures have hydro- gen atoms on the carbon atom next to the double bond, so-called allylic hydrogen atoms. S S S S S S S S8 ring S Ring opening S S S S S S S S S S S SX Fig. 22 Types of sulphur bridges in sulphur cross-linking: mono-, di- and polysulphidic 118 TYPE OF BINDING C-S binding S-S binding S-S-Sx binding C-C binding BINDING ENERGY [kJ/mol] 285 268 < 268 356 Tab. 3 Binding energies at a glance When cross-linking with sulphur, the rubber molecules are chemically linked by sulphur bridges. These can form in different ways; depending on the cross-linking system used, cross-link node structures are formed from just one sulphur atom (monosulphidic sulphur bridges, S1), from two sulphur atoms (disulphidic, S2) or from more than two sulphur atoms (poly sulphidic, S-S-Sx). Properties of the cross-link nodes Monosulphidic bridges have the highest binding energy of the three types of sul- phur bridges and are therefore the most stable, while polysulphidic bridges have the lowest binding energy. Sulphur bridges are always less stable than bonds between two carbon atoms (→ Tab. 3). Elastomers with predominantly mono- and disulfide structures exhibit less per- manent deformation, better thermal re- sistance and are less prone to reversion than elastomers with a high proportion of polysulfide bridges. In contrast, elastomers with predominant- ly polysulphide structures are more resist- ant to fatigue. This is due to the fact that poly-sulphide cross-linking sites can mi- grate along the polymer chain at elevated

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5. Cross-linking chemistry Rubber elasticity Leathery condition Steel elasticity I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A 0.25 … 7 phr sulphur 7 … 25 phr sulphur 25 … 40 phr sulphur R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P y t i c i t s a E l Degree of cross-linking Fig. 23 Influence of the sulphur content on the material properties S L A E S C I T A T S There are no clear boundaries between the cross-linking systems. The amount of sulphur used not only in- fluences the type of sulphur bridges, but also the number of cross-linking points. If the usual sulphur content in the rubber compound is a few percent by weight, it is referred to as soft rubber, while very high sulphur contents of over 25 percent by weight are referred to as hard rubber. temperatures without causing chain scis- sion. This leads to a certain self-healing effect, local stress peaks can be reduced and early failure under dynamic load is avoided. Cross-linking systems Which type of linkage is created depends heavily on the amount of sulphur used. At higher sulphur levels, predominantly S-S-Sx compounds are formed; in low-sul- phur systems, S2 bridges tend to form. Sul- fur donor systems predominantly produce S and S2 bridges. In addition to sulphur and/or sulphur donors and activators such as zinc oxide and stearic acid, a sulphur crosslinking system also contains one or more accelerators. The ratio of accelerator to sulphur char- acterizes the cross-linking system. A low ratio is called a "Conventional Vulcaniza- tion System" or CV system; a high accel- erator: the sulphur ratio is referred to as an "Efficient Vulcanization System" or EV system. The "Semi-efficient Vulcaniza- tion System" or SEV system lies between the "Conventional" and the "Efficient Vul- canization System" (→ Tab. 4). CROSS-LINKING SYSTEM Conventional Vulcanization (CV) Semi-efficient Vulcanization (SEV) Efficient Vulcanization (EV) SULPHUR ACCELERATOR RATIO S-S-SX BRIDGES S1 BRIDGES [phr] [phr] ACCEL. : SULPHIR 2.0 … 3.5 0.4 … 1.2 0.1 … 0.6 1.0 … 1.7 1.2 … 2.5 0.7 … 2.5 0.4 … 0.8 2.0 … 5.0 2.5 … 12.0 [%] 95 50 20 [%] 5 50 80 Tab. 4 Sulphur cross-linking systems G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 119 X E D N I

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Materials and Process Engineering At medium sulphur doses, leather-like materials are obtained that have no useful properties. Typical products made of hard rubber in- clude ice hockey pucks, mouthpieces for woodwind instruments such as the clari- net or saxophone and high-quality combs. 5.2 CROSS-LINKING WITH PEROXIDES Peroxide cross-linking is a radial cross-link- ing process in which coagents are often used in addition to the peroxides. Peroxides are usually used that decompose within a few minutes in the temperature range of +150 to +220 °C and form active radicals. In a subsequent step, these radi- cals react with the main chain of the rubber and transfer the radical function to the rubber molecule. The linking of two such polymer radicals provides a cross-link node. The two chains are linked directly via a thermally very stable C-C bond (→ Fig. 24). The use of coagents, also known as coac- tivators, can increase the efficiency of the crosslinking reaction: the cross-linking density increases and some coagents ad- ditionally accelerate the vulcanization. Their use makes it possible to reduce the amount of peroxide used and the vulcan- izates exhibit higher elasticity. Coagents have at least 2 active double bonds that tend to form radicals; typical representatives include triallyl cyanurate, triallyl isocyanurate, di- or tri-functional acrylates and methacrylates as well as short-chain 1.2 polybutadienes. The use of coagents changes the cross-link node structure of the radical crosslinking: the polymer radicals formed in the first step now react with the coagent molecule and transfer the radical function to the polymer. A single radical transfer then results in several crosslinking-effective subsequent reactions. The coagence mol- ecule acts as a bridging molecule and in- creases the distance between the bridged rubber chains (→ Fig. 25). The formation of radicals requires higher temperatures during vulcanization than is the case with sulphur cross-linking. A re- arrangement of the formed cross-linking bridges is not possible here. Decomposition of the peroxide → Radical formation R O O R Peroxide Temperature 2 R O● Radical Transfer of the radical on the polymer chain R O● H ● R OH Recombination → Networking point ● ● Fig. 24 Reaction mechanism of peroxide cross-linking 120

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5. Cross-linking chemistry Polymer chain Polymer chain O N N O N O Fig. 25 Peroxide crosslinking: cross-link node with coagent triallylcyanurate (TAC) Polymer chain There are also peroxide-crosslinked mate- rials that do not benefit from a tempering step or where post-heating is not possible due to the manufacturing process (e.g. continuous production by extrusion) or component size. Excessive tempering leads to ageing and can damage the com- ponent. Compared to sulphur-crosslinked elasto- mers, peroxide-crosslinked elastomers are more heat-resistant and exhibit less permanent deformation (lower compres- sion set). The disadvantages of peroxide crosslinking are, in addition to the sensi- tivity to oxygen and the lower flexibility in the adjustment of the crosslinking characteristics, above all the lower tear resistance and a lower tear propagation resistance as well as poorer fatigue resist- ance under dynamic stress. Peroxide crosslinking is mainly used for elastomers with only a few or no double bonds in the main chain (→ Tab. 5). TEMPERING Peroxide-crosslinked molded parts are often tempered after vulcanization. In this process, the elastomer component is reheated at an elevated temperature in the oven for a certain period of time. The dwell time and temperature depend on the polymer and compound, and the thickness of the component also plays an important role. Common post-heating temperatures are between +150 °C and +220 °C, usual reheating times between 4 and 24 hours. Post-heating serves to optimize the com- ponent properties. The cross-linking re- action, which may not have fully taken place during vulcanization, is terminated. Volatile components and unwanted re- action products can escape from the ma- terial, which reduces the odor and im- proves some physical properties, especially strength and setting behavior. Tempering allows certain formulation components such as antioxidants or ozone protection agents to migrate to the component surface and develop their full effect there. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 121 X E D N I

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Materials and Process Engineering RUBBER SULPHUR PEROXIDE BISPHENOL DIAMINE METAL OXIDE PLATINUM RESIN NR IR BR SBR IIR XIIR CR NBR HNBR EPDM CM CSM EVM ACM AEM FKM VMQ/FVMQ ECO B B B B B B F B B B F F D D D D B B B B B B B B B B B B D D D B B B B B B B F F B B B F B = possible D = possible, but unusual F = special chemistry or special types Tab. 5 Types of crosslinking chemistry for the most common rubber classes 122

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6. CARRIER PARTS 6. Carrier parts I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I If rubber elasticity and high rigidity have to be realized in one component, elasto- mers are mechanically or chemically bonded to metal or plastic carriers. The carrier or stiffening element then gives the elastomer molded part the necessary dimensional stability. Suitable reinforc- ing elements are either made of metallic materials or thermoplastic or duromer plastics. Depending on the application, quenched and tempered steels as well as stainless and acid-resistant steels are used in ad- dition to unalloyed steels. Non-ferrous metals are also used, in particular non-ferrous metals such as copper, zinc, brass or bronze as well as light metal alu- minum alloys. In the field of plastics, technical or high- performance thermoplastics such as ali- phatic or partially aromatic polyamides, polybutylene terephthalate, poly-phe- nylene sulphide, polyether ether ketones and duromers are used. Extensive stiff- nesses are achieved here in particular by using glass or carbon fiber-reinforced grades. Examples: Unalloyed steels according to DIN EN 10139 y D C 01 (1.0330) Rust and acid-resistant steels in accordance with DIN EN ISO 3506 y 1.4301 (X 5 Cr Ni 1810) y 1.4404 (X2CrNiMo17-12-2) y 1.4571 (X 6 Cr Ni Mo Ti 17122) y 1.4112 (X 90 Cr Mo V 18) y 1.4542 (X 5 Cr Ni Cu Nb 174) R O F S L A E S Y R A T O R S N O T A C I I L P P A Fig. 26 Section through a single-layer system; scanning electron microscope image R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Rubber Cement Pre-treatment Rubber Cover Primer Pre-treatment Metal Metal S L A E S C I T A T S Fig. 27 left: One-layer system (cement), right: two-layer system (primer + cover) Quenched and tempered steels according to DIN EN 10132 y 1.0501 (C35) y 1.0503 (C45) y 1.1191 (CK 45) Plastics y PA 6.6 GF30 y PPS GF30 y PEEK Today, the majority of all elastomer com- posite parts are produced with an insep- arable chemical bond that is created si- multaneously via the vulcanization of the elastomer in the molding tool under pres- sure and temperature. In some applica- tions, physical anchoring of the elastomer to the reinforcing part is sufficient to en- sure the function of the composite part. G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 123 X E D N I

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Materials and Process Engineering Both the design and manufacture of composite components, in which the bonding partners are chemically bonded, require some attention. DESIGN OF THE COMPOSITE COMPONENT y the rubber layer on the carrier part should be at least 0.5 mm so that the flow speed of the elastomer is kept as low as possible during the filling pro- cess. If the gaps are too narrow, there is a risk that the binder will be pushed off the carrier part by the nozzle effect, resulting in bonding and/or flow de- fects y if the carrier part is only to be partial- ly overmolded with elastomer, the carrier part must provide sufficient surface area for the imprint edges of the tool. If possible, the width of the impression surface should be at least 1 mm y in the case of fully encapsulated mold- ed parts, the carrier part must be centered in the tool using centring cams or pins. In addition, the bonding forces can be increased if undercuts or holes on the carrier part enable addi- tional mechanical anchoring of the elastomer y for tight tolerances or fits, the carrier parts should be large enough for any necessary finishing work y with thermoplastics in particular, care must be taken to ensure that the carrier parts are still dimensionally stable at vulcanization temperature so that they do not deform during the vulcanization process PRETREATMENT OF THE CARRIER PARTS In order to ensure good chemical bond- ing and thus a long service life of the composite component, appropriate surface treatment of the carrier parts is essential. y the carrier parts must be cleaned of adhering dirt and degreased. The sur- face is then enlarged and roughened using the following methods: • mechanical roughening: under the influence of a solid abrasive, e.g. sand, under pressure, impurities are removed from the surface and the surface is roughened • acid-cleaning: the reaction with acid is a cleaning step to remove unwanted metal oxides such as rust, corrosion and tarnish layers, which are usually associated with the base metal • phosphating: the chemical process of zinc or iron phosphating gives unalloyed steels a fine crystalline needle-shaped layer of metal phos- phates on the surface. The metal phosphate layer is firmly anchored in the metal surface, increases the sur- face area and provides protection against rust. It also enables the ap- plication and adhesion of binding agents y after surface pre-treatment and acti- vation, the binder system is applied. The aqueous or solvent-based binders are applied in one or more layers by brushing, spraying, tumbling or dipping onto the pre-treated carrier parts. The water or solvent used must then be completely removed. In many cases, the binder system must be baked in a subsequent step by heat treatment in an oven 124

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6. Carrier parts If the carrier part has a large volume and a large mass has to be heated during vulcanization of the rubber compound, it is advantageous to preheat the car- rier parts in prepared ovens y particularly in the injection molding process, there is a risk that the binder will be sheared off the carrier part by the high injection pressures of the rubber mixture and the chemical bonding will be faulty. The design of the injection molds should therefore provide for a right-angled arrangement of the injection nozzles to the carrier part y the process parameters (pressure, temperature, heating time) must be selected in such a way that not only the vulcanization of the rubber com- pound is largely completed when demolding, but also the chemical re- actions that must take place to form the bond between the elastomer and the carrier part have been completed y activated carrier parts treated with a binder must be stored properly. The environment must be dry and free of dust and grease. Temperatures that are too high or too low will impair the subsequent bonding of the elastomer, as will excessively long storage times for the pre-treated carrier parts y for the best possible bonding of the elastomer to the carrier part, the bonding agent system used must be matched to the rubber compound to be bonded and the material of the carrier part to be bonded. Water-based systems are preferable in terms of environmental and health protection, but are more challenging to use. The following three binder systems are commonly used. • phenolic resins with a hardener • polymer dispersions with a filler and a crosslinker • reactive silanes These systems are safe to work with and offer very good mechanical, thermal and chemical resistance of the elastomer composites after vulcanization. PRODUCTION OF THE ELASTOMER COMPOSITE COMPONENT y good chemical bonding of the rubber compound to the carrier part is only achieved if the total cycle time re- quired to heat up the carrier part in the vulcanization process is taken into account in the total cycle time. In par- ticular, if the carrier parts are placed cold in the hot shaping tool, the time required for heating up to temperature must be taken into account, otherwise the degree of cross-linking of the elastomer and the chemical bonding to the carrier part will be insufficient. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 125 X E D N I

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Materials and Process Engineering 7. FROM RAW MATERIAL TO FINISHED PART 7.1 PROCEDURE Various processing steps are necessary to produce the elastomer molded part from the many raw materials. Specialist knowl- edge and suitable machine technology are required in each individual process step so that rubber components can be manufactured economically and to a high quality. The most important processing steps are 1. Incoming inspection and weighing of the raw materials mixer and two downstream rolling mills, one for mixing and the second for mold- ing. This is usually followed by a batch-off unit, in which the mix in the form of con- tinuous skins or continuous strips is cooled to room temperature and in some cases provided with a release agent so that the skins and strips do not stick to- gether during storage of the finished mixtures. The mixing process in the internal mixer consists of the following four steps: 2. Production of the rubber compound 1. Shredding of the rubber supplied as including strainers bales 3. Production of a preform (blank) 4. Article production through shaping 2. Incorporation of fillers and plasticizers (incorporation) and vulcanization 3. Separation of the filler agglomerates 5 Reheating 6. Post-processing (deburring, grooving, washing, etc.) 7. Final inspection (dispersive mixing) 4. Distribution of the comminuted fillers in the rubber matrix (distributive mix- ing) Not all process steps are always run through to the finished article. For exam- ple, many rubber mixtures are not strained and some molding processes do not re- quire a special preform. Post-heating of elastomer components is only necessary for certain compounds and not necessar- ily for all applications. Not all items re- quire special post-processing either. 7.2 MIXTURE PRODUCTION In the mixing process, all raw materials are processed into a homogeneous rubber compound. A mixing line in a typical mixing plant for the production of rubber compounds consists of a kneading unit, the internal First, the raw rubber is prepared by crush- ing the raw bales and bringing them up to temperature using the high shear forces that occur in the internal mixer. The vis- cosity of the rubber is reduced, it be- comes flowable and can therefore absorb the other components of the mixture more easily. The next step is to add fillers and plasti- cizers, known as incorporation. The mix- ture is initially very inhomogeneous and has hardly any cohesion. Through further mixing, an externally homogeneous mass is gradually formed. The air, which is caught up between the filler particles is displaced and the empty spaces on the surfaces of the particles are filled with rubber. 126

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7. From raw material to finished part Once this process is complete, the mix- ture appears to be homogeneous. How- ever, there are still filler agglomerates in the mix at this point. These are broken up (divided) by the subsequent dispersive mixing, so that their volume decreases and their surface area increases. This is necessary in order to optimally wet the fillers with the rubber; this is the only way to achieve the reinforcing effect of the fillers in the subsequent product. At this stage, the other components of the formulation, such as anti-ageing agents, pigments, processing aids, acti- vators, coagents and possibly also crosslinking chemicals, are usually added. Finally, so-called distributive mixing achieves the optimal distribution of all raw materials in the rubber matrix. Only now is a completely homogeneous rub- ber mixture created. A size comparison of the individual com- ponents shows the great demands that the entire mixing process has to meet for the various components that must be mixed together as homogeneously as possible. Viewed in a proportion model, in which spaghetti illustrates the polymer molecules, the sizes range from 8 mm to 30 m (→ Fig. 28). Polymer ball Carbon black aggregate ZnO particles (detail) Proportion model: Spaghetti Length [nm] Diameter [nm] Particles Length Diameter [m] [m] 1,000 … 3,000 0.15 Rubber molecule 10 … 30 0.015 50 190 320 4 5,000 0.8 0.5 1.9 3.2 0.04 50 0.5 0.5 1.8 0.015 50 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 50 50 Polymer ball Carbon black aggregate 330 180 Carbon black aggregate N990 0.15 5,000 0.8 Plasticizer ZnO Sulphur/Accelerator 0.008 0.008 Fig. 28 Comparison of the size of the components of a rubber compound 127 X E D N I

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Materials and Process Engineering In addition to the common technology of mixing in batches in kneaders (→ Fig. 29) and on mixing rollers, rubber compounds can also be produced continuously using extruder processes. These are less com- mon and, due to the longer start-up and shut-down times, are mainly used in mixing plants where large-volume com- pounds are produced with only a few formulation changes. The schematic structure of an internal mixer, also known as a ram mixer, is shown in → Fig. 29: The heart of the mixer is the temperature-controlled mixing chamber, which is closed by the ram and the fold- ing saddle in which two rotating mixing blades (rotors) provide the mixing power. Fig. 29 Structure of an internal mixer (here with a tangential rotor geometry) 128 They are either tangential (run next to each other with friction) or intermeshing (run in parallel with overlap). The mixing chamber, the rotors and the discharge saddle are temperature-con- trolled so that the heat introduced into the mix by the shear forces can be dissi- pated in a controlled manner. The advan- tage of the intermeshing rotor system is the higher energy input into the mix and therefore a significantly better dispersive mixing effect compared to tangential systems. Tangential internal mixers mix more gently and offer more mixing vol- ume for the same size. The pre-weighed raw materials are fed into the mixing chamber through the feed chute, which is closed with the plunger during the mixing process and thus keeps the mix under pressure. At the end of the mixing process, the saddle at the bottom of the mixing chamber is opened and the mix falls downwards out of the mixer. The mixing chamber volumes of conven- tional inline mixers range from 30 l to large mixers with over 700 l. Depending on the density of the raw materials, batch weights of 25 kg to over 500 kg can be achieved with these mixers. Due to the mixing and shearing energy required, high drive power is needed. Rolling mills are generally used as down- stream aggregates after internal mixers. The rollers of a rolling mill are operated at different speeds. The rear roller runs 10 to 30% faster than the front roller (friction), which creates the shear forces required for a good mixing effect in the roller gap.

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7. From raw material to finished part The gap width of the roller mills is adjusta- ble; the addition of mixing components takes place with a large gap width and the gap is reduced for subsequent homogeni- zation (→ Fig. 30). On the first roller mill, the mix, which can reach temperatures of more than +140 °C during the mixing process in the internal mixer, especially with high filler contents, is cooled to temperatures below +80 °C and homogenized again in the narrow roller gap. Temperature-sensitive raw materials such as cross-linking chemicals can be mixed in safely on the first roller mill. The second rolling mill is essentially used for remixing, shaping and transfer to the downstream batch-off system. Alternatively, mixtures can also be pro- duced in several stages. In the first step, the basic mixture is produced without temperature-sensitive chemicals and runs through the same mixer line again completely after depositing, whereby heat-sensitive raw materials such as cross-linking chemicals can be mixed in the internal mixer in the second pass. A higher mixing quality is often required for safety components or delicate sealing shapes such as sealing lips. Therefore, downstream homogenization via a mix- ing roller or a multi-stage mixing process is mandatory for these applications. Rub- ber compounds of these product groups are often subjected to an additional pro- cess step, straining. Using an extruder with fine-mesh nets, the compounds are strained under high pressure so that all particles as of a certain size, such as un- sheared mixture components or undivided oversized grains, are reliably removed. At the end of the mixing line, either mixing skins are cut, a wide endless belt is deposited or narrow strips are cut and also deposited endlessly in containers. For further processing, it may be neces- sary to change the shape of the rubber mixture, to continuously fill the molding machine or to be able to insert precisely fitting blanks into molding tools, for ex- ample. The mixture is therefore often formed into sheets, cords, strips or indi- vidual blanks using an extruder. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 30 Illustration of a mixing roller 129 X E D N I

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Materials and Process Engineering This step is used exclusively for pre- forming and not for mixing in other raw materials. tolerances, the rubber compound is approved for further processing in the forming area. All steps in the production and preparation of the mix are subject to continuous quali- ty monitoring. In a certified mixing plant, all raw materials are sourced from certified suppliers. In addition to the manufacturer certificates of the individual raw material batches, the quality of the raw materials is randomly tested as part of the incoming goods inspection. After a positive result, the raw materials are approved for use. The mixing processes are precisely de- fined by operating formulation specifica- tions and exact mixing instructions with regard to weighing tolerances and the time at which the raw materials are added to the kneader or rolling mill. During the individual mixing phases, process param- eters such as energy input into the rubber mixture, rotor speed, temperature, mixing times, as well as stamp movement and pressure etc. are precisely controlled. Pro- cess specifications are also defined for the rolling mills, so that all process steps can be controlled until the finished com- pound webs are discharged into the batch-off system. If only a few batches of a rubber com- pound are produced, each batch is final- ly checked; for this purpose, the rheolog- ical properties as well as the density and the mechanical values (hardness, tensile strength, breaking strain, compression set, possibly others) are determined. For larger campaigns, the testing effort can be reduced in accordance with QS speci- fications by means of skip-lot random sample testing procedures. If all the measured values are within the specified 7.3 SHAPING AND VULCANIZATION Elastomer molded parts are usually man- ufactured using processes in which the shaping and vulcanization of the rubber compound take place in the same place and at the same time. In the manufacture of continuous rubber products such as hoses and profiles, however, the shaping is separated from the vulcanization in tems of space and time. CHOICE OF SHAPING PROCEDURE Various processes are available today for the production of elastomer molded parts. The choice of the most technologically and economically suitable process depends on the following parameters: y Number of units y Dimensions of the component y Flowability of the rubber compound y Component geometry and tolerances Tool costs play an important role in a profitability analysis and must be in a rea- sonable proportion to the requested number of units. The design of the molded part is also im- portant when considering costs, especial- ly the required tolerances and the finished processing state. Burr-free molded parts are often required on the inquiry drawings, which necessitates the complete deburr- ing in an additional process step. This is often not technically required for the ap- plication and can cause costs in individual 130

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7. From raw material to finished part cases that are higher than the total manufacturing and material costs of the molded part itself. It makes sense to specify the permissible burr expansion on the drawing, e.g. 0.3 × 0.5 mm (maximum dimension of the thickness and length of the burr). In the production of molded parts, dimension- al deviations occur due to manufacturing tolerances during tool production, the process for producing the elastomer com- pound, the molding process and the shrinkage behavior of the elastomer com- pound during vulcanization. The permissible tolerances for molded rubber parts are described in DIN ISO 3302. The following → Table 5 is an excerpt from part 2 of this standard. The stand- ard distinguishes between dimensions linked to the mold (F) and dimensions linked to the positive fit (C). Due to the process, the dimensions linked to the form fit (C) have a greater tolerance than the dimensions linked to the mold (F). CLASS M1 CLASS M2 CLASS M3 CLASS M4 F ± C ± F ± C ± F ± PERMISSIBLE DIMENSIONAL TOLERANCES IN mm 6.3 10 16 25 40 63 100 160 0.10 0.10 0.15 0.20 0.20 0.25 0.35 0.40 0.10 0.15 0.20 0.20 0.25 0.35 0.40 0.50 0.15 0.20 0.20 0.25 0.35 0.40 0.50 0.70 0.20 0.20 0.25 0.35 0.40 0.50 0.70 0.80 0.25 0.30 0.40 0.50 0.60 0.80 1.00 1.30 PERMISSIBLE DIMENSIONAL TOLERANCES IN % C ± 0.40 0.50 0.60 0.80 1.00 1.30 1.60 2.00 F ± 0.50 0.70 0.80 1.00 1.30 1.60 2.00 2.50 C ± 0.50 0.70 0.80 1.00 1.30 1.60 2.00 2.50 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P NOMINAL DIMENSION FROM TO 0 6.3 10 16 25 40 63 100 160 0.30 (* 0.50 (* 0.80 (* 1.50 1.50 Tab. 6 Permissible dimensional tolerances for molded parts (DIN ISO 3302) (* – Values by agreement only) 131 X E D N I

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Materials and Process Engineering If no tolerance class is specified in the product drawing, class M3 (medium de- gree of accuracy) usually applies. Produc- tion in tolerance classes with a higher de- gree of accuracy only makes sense if this is crucial to the function of the compo- nent. Excessively tight tolerances make the product unnecessarily expensive. INFLUENCE OF THE RUBBER COMPOUND Not every rubber compound can be pro- cessed using every process. Formulations often have to be adapted when switching from one molding process to another. In order to assess the processing behavior of a rubber compound, its flowability and the speed of vulcanization (cross-linking kinetics) must be determined as a function of temperature. These rheological tests are carried out using appropriate rheome- ters, which are also used to perform a constant control of the materials – see also → „5. Cross-linking chemistry“, Fig. 21, page 116. The rheometer curve shows the change in torque over time at a fixed tempera- ture. As the cold rubber compound in- serted into the mold heats up, it initially begins to flow and the torque decreases. As soon as the cross-linking reaction be- gins, the flowability decreases and the viscosity of the mixture and thus also the torque increase. After vulcanization is complete, the torque no longer changes and reaches a stable final value (→ Fig. 21, page 116). It is the task of the compound developer to adapt the flow and cross-linking be- havior of the rubber compound to the re- spective processing method by adjusting the compound viscosity, selecting the cross-linking system and the remaining compound structure. TOOL COMPETENCE In addition to the compound composi- tion, the tool must also be matched to the selected shaping process. The right choice of tool steels and the manufacture and maintenance of the tools are important prerequisites for successful toolmaking and optimal elastomer processing. In general, tools are manufactured by machining such as turning, milling and drilling. How- ever, electro-erosion is also used as a machining process for many tools today. The correct choice of steel grade and the correct surface treatment of the molding tools are of particular importance, as rub- ber compounds sometimes contain a high proportion of wear-promoting fillers and cause corrosion on the tool steels due to ox- idizing precipitates during vulcanization. Stainless steels with more than 15% chro- mium as the main alloy component are of- ten used, which have a sufficiently high chemical resistance. Alternatively, the ground and polished tool surfaces can be made sufficiently wear-resistant and corro- sion-resistant by subsequent hard chrome plating or special coating. The quality of the tools and especially their surfaces must be monitored constantly and maintained through preventive main- tenance and repairs. The easiest way to do this is to assess the surface quality of the molded part itself. Even the slightest changes to the tool surface are visible as a mirror image on the molded part, often long before the dimensional change can be measured. 132

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7. From raw material to finished part However, the professional molding pro- cess is also suited for the production of very large component dimensions, for wind turbine seals, for example. The disadvantage is the longer heating times compared to the other methods, as the blank has to be heated from ambient temperature to mold temperature (usu- ally +160 – +180 °C). Depending on the size of the blank, this can take several minutes because rubber compounds generally conduct heat poorly. TRANSFER MOLDING The transfer molding process (TM) is a further development of compression molding. Here too, a blank is used, which in contrast to CM, is placed in a transfer unit that is connected to the actual mold via small channels. When the piston of the transfer unit is moved in, the blank is pressed and the rubber mixture is inject- ed via the channels into the hot, closed mold cavity, where it begins to vulcanize. The finished component and the remain- ing material in the transfer pot can be demolded as soon as vulcanization is complete. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 31 Principle of compression molding – CM 133 X E D N I 7.4 OVERVIEW OF THE SHAPING PROCESS In discontinuous processes, the shaping of rubber compounds generally takes place at the same time as the chemical cross-linking reaction (vulcanization). In most cases, molding and vulcanization take place in closed molds (cavities). The most important molding processes for technical rubber products are: y Compression molding (CM) y Transfer Molding (TM) y Injection molding (IM; hot runner and cold runner technology) y Extrusion processes; roller head systems COMPRESSION MOLDING Compression molding (CM) is one of the oldest molding processes in elastomer processing. A prefabricated blank of a de- fined weight is placed in the open mold, which is preheated to vulcanization tem- perature, and formed by closing the mold in a press. The heated mold plates heat the blank, which begins to flow and fills the mold, allowing air and excess mate- rial to escape from the parting line of the mold. Once the flow process is complete, the rubber compound begins to vulcanize. The finished component can be demolded as soon as vulcanization is complete. The burr created along the parting line of the two mold halves must be removed in a subsequent process step. The advantages of compression molding lie in low-cost tools, which means that smaller quantities can also be produced economically. Efficiency can be increased by using multiple cavities, possibly with automated blank loading.

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Materials and Process Engineering The advantage of transfer molding is that several cavities can be filled simultane- ously with one blank and that the rubber mixture is better distributed through the channels, making more complicated designs possible. In addition, the blank is already heated in the transfer pot, which results in shorter closing times and reduces the formation of burrs on the component. INJECTION MOLDING In the injection molding (IM) process, the rubber compound is fed into a plasticiz- ing unit in the form of continuous strips or round cords, where it is preheated and then injected under high pressure via hot distribution channels into the hot, closed mold cavity, where the rubber compound begins to vulcanize once the mold is com- pletely filled. Transfer molding can therefore be used to produce medium to high-precision components economically. Vulcanized material in the channels and in the transfer unit as well as burr forma- tion on the component result in waste that must be disposed of. Components usually have to be reworked. The demands on the rubber compound are higher compared to CM: In order to be pressed through the channels, the rub- ber compound must flow better, and the early addition of heat and the longer flow paths must not lead to premature vulcan- ization. Fig. 32 Principle of transfer molding – TM 134 With this so-called hot runner technolo- gy, once vulcanization is complete, the vulcanized residual material is removed from the divider channels (sprues), sepa- rated from the component and disposed of in addition to the finished component. The position and number of injection points can be precisely matched to the component geometry and the compo- nent volume; working with multiple cav- ities, which can be individually injected, is also common. As the rubber compound is already pre- heated by the heatable screw conveyor and the mechanical work caused by plas- ticizing, it can flow much more easily through the narrow distribution chan- nels. The required vulcanization temper- ature is thus reached more quickly and very short closing times can be achieved, making the injection molding process the fastest of the three molding processes. Injection molding processes do not re- quire blank production and can be fully automated. Similar to transfer molding, the rubber mixtures must have good flowability; the advantages of short cy- cle times can be achieved above all with compounds that vulcanize quickly, which sometimes limits their storage stability.

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7. From raw material to finished part Fig. 33 Principle of injection molding – IM With increasing quantities, TM and IM processes become more interesting; CM is often the most economical for large outer diameters, even with larger quan- tities (→ Fig. 35). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 34 Principle of cold runner technology 135 X E D N I With hot runner technology, the sprues produced must be removed and disposed of after each cycle. This type of shaping is associated with high investment costs for injection mold- ing machines, tools and distribution channels, which is why injection molding processes are particularly economical for large quantities. COLD RUNNER TECHNOLOGY In the injection molding process with cold runner technology, the manifold plate in which the channels are located is thermally separated from the hot mold and can be individually temperature-controlled. This means that the rubber mixture re- maining in the channels does not vulcanize and there are no sprues that have to be separated from the component and dis- posed of. In addition to this additional process step, considerable material can also be saved, which can lead to a significant reduction in costs, especially with expensive rubber compounds. The injection molding process with cold runner technology is particularly well suited for the fully automated production of molded parts, as the use of so-called flashless tools means that rework-free components can be produced without waste. Here, too, the high investment and tool costs mean that the process only pays off for larger quantities. CHOICE OF PROCEDURE The cost-effectiveness of the three shap- ing processes depends primarily on the size of the component to be produced and the required quantities.

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Materials and Process Engineering EXTRUSION PROCESS Extrusion processes allow for the contin- uous production of endless components such as hoses, cables, profiles or sheet ma- terial. The rubber compound is drawn into the extruder and continuously conveyed by the rotating screw, heated and pushed out through a die nozzle at the end of the extruder. The profile cross-section is shaped in the process. In addition to prod- ucts such as round cords, cables or hoses with simple cross-sections, complicated geometries, such as those used in sealing or hollow chamber profiles, can also be re- alized (→ Fig. 37). A frequently occurring phenomenon in the extrusion of polymers, in which a polymer strand is pressed through a die to produce the desired sample, is strand expansion. Depending on the rubber compound and the process parameters, it ensures a significant increase in the di- ameter of the rubber strand after it has passed through the narrow openings of the die (→ Fig. 37). Fig. 36 Examples of strand expansion The reason for this is the viscoelastic ma- terial behavior of the rubber compound, whose polymer molecules disperse sig- nificantly as they pass through the tool nozzle and then return to their lower- energy ball state. When running in a new nozzle disc, an iterative adjustment process is usually required until the desired target contour is achieved. The extruder is followed by equipment used to vulcanize the extrudate. The cross-linking of the rubber mixture is either continuous or discontinuous. y t i t n a u Q TM Transfer Molding IM Injection Molding CM Compression Molding Fig. 35 Influence of component size and quantity on the economic efficiency of shaping processes Outer diameter [mm] 136

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7. From raw material to finished part y sufficient surface quality: both after extrusion and after the vulcanization process Both the expansion of the strand and changes in shape until the elastomer is fully cross-linked are subject to certain fluctuations and are the reason why the usual tolerances cannot be realized in the extrusion production of elastomer articles. Manufacturing tolerances for extrudates are specified in DIN EN ISO 3302-1 E1 to E3. The usual standard E2 is approx. 3 times higher than the usual standard M3 for mold-bound processes, which must be taken into account when designing the product (→ Table 6). Deviations from the standard can occur and must be checked depending on the material, vulcanization process and contour complexity. Profiles used in sealing technology can be supplied by the meter or in prefabricated form (e.g. sealing rings, profile sections). Water Steam Filling opening I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 37 Extruder for the production of sealing profiles 137 X E D N I With continuous production, the heat re- quired for vulcanization is introduced into the molded rubber compound using infra- red radiators (IR), hot air systems (HL) or microwave systems (UHF), often in com- bination. Alternatively, the extrudate can also be passed through a hot salt bath. In all processes, the material is brought to temperature without pressure and cross- linked. The rubber mixture must be adapt- ed to the pressureless vulcanization and must not contain any components that can outgas or form gaseous components in the heat, as the extrudate would other- wise foam up and form an irregular sur- face. In discontinuous production, cross-linking takes place in an autoclave with steam. The pressure acting on the material pre- vents the outgassing of volatile compo- nents and thus the formation of pores in the component. The composition of the rubber compound is less critical here. The choice of the appropriate production process is primarily dependent on the ma- terial as well as the geometry and thick- ness of the cross-section. For example, an inherent curvature required for the appli- cation can be vulcanized into the profile in the autoclave, which is not possible in con- tinuous production. Regardless of the manufacturing process, an extrudable rubber compound must meet the following criteria: y reproducible strand expansion y stability: The still uncured mixture must not deform or “flow away” in an undefined manner after molding, but must have sufficient dimensional sta- bility for the subsequent process steps

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Materials and Process Engineering During assembly, a seal is produced from the finished vulcanized yard goods in fur- ther work steps. The most common prod- uct is a closed sealing ring in which a joint is created by gluing or impact vulcaniza- tion. From a technical point of view, this joint always represents an area of lower quality (surface quality, tensile strength, elongation at break), which must be tak- en into account in the subsequent appli- cation. When bonding, the sealing profile is usu- ally cut at an angle; this increases the bonding surface and leads to a higher load-bearing capacity of the joint. The choice of adhesive must be matched to the elastomer. Above all, the temperature and media resistance, but also the stiff- ness and elasticity of the adhesive should be comparable to those of the elastomer. During butt vulcanization, the sealing profile is usually cut at right angles. The ends to be joined are joined under pres- sure and temperature in a vulcanization tool that reproduces the negative shape of the sealing profile. Before the mold closes and the two ends are joined to- gether, a thin film of the elastomer raw compound is placed between the ends, which enables the two profile ends to form a tight fit. The joint created in this way has the same flexibility and identical media and temperature resistance as the base material of the sealing profile. From a technical point of view, butt vulcanization is therefore the preferred solution. ROLLER-HEAD SYSTEM Flat material is also produced from sheets and webs. This is primarily used in sealing technology as a semi-finished product for further processing into flat gaskets and NOMINAL DIMENSION [mm] TOLERANCE CLASS [mm] FROM TO E1* E2 E3 0 1.5 2.5 4.0 6.3 10 16 25 40 63 1.5 ±0.15 ±0.25 ±0.40 2.5 ±0.20 ±0.35 ±0.50 4.0 6.3 ±0.25 ±0.40 ±0.70 ±0.35 ±0.50 ±0.80 10.0 ±0.40 ±0.70 ±1.00 16 25 40 63 ±0.50 ±0.80 ±1.30 ±0.70 ±1.00 ±1.60 ±0.80 ±1.30 ±2.00 ±1.00 ±1.60 ±2.50 100 ±1.30 ±2.00 ±3.20 Tab. 7 Manufacturing tolerances according to DIN EN ISO 3302-1 (* partially possible in individual cases) membranes. The flat material is produced using pressing tools as individual sheets or continuously as sheet material in so- called roller head systems. An extruder – equipped with a wide ex- trusion head and wide slot die – feeds the plasticized and heated rubber mixture into a 2-roll calender. In the roll nip, the web is calendered to a defined thickness and width and then pressed against a rotating heating roll with the help of a steel belt and continuously vulcanized. Map-Marker-Exclamation Connection points must be taken into account in the application 138

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7. From raw material to finished part I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A Extruder Two roll calender Filing R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Fig. 38 Principle of a roller head system The edges are then trimmed, the surface powdered if necessary and the sheets rolled up or cut into strips or individual sheets. When producing sheet material, a second component (e.g. PTFE film as a permea- tion barrier, fabric for mechanical rein- forcement) can also be fed into the system and be chemically bonded with the elas- tomer during vulcanization. The flat material is assembled into flat gaskets by means of separating post- processing (e.g. punching, drilling, plotting, cutting, laser or water jet cutting). (PRESS) SINTERING OF PTFE Sintering is generally a process in which powdery or granular starting materials are mixed and "baked" together by pressing, usually under temperature and pressure. There are processes in which agglomer- ates are first pressed into a mold and baked under high pressure and tempera- ture. There are also processes in which work can be carried out without pressure. ticles, the process differs from casting processes in that in the latter the entire component is formed from a melt. Sintering processes are widely used in ceramics production and metallurgy, but are also used in the manufacture of semi-finished products made from non- fusible plastics such as the ultra-high- molecular-weight plastics polyethylene (UHMPE) and polytetrafluoroethylene (PTFE). Pressing and sintering technologies enable the production of geometrically simple semi-finished products such as solid rods, hollow rods and sheets. Due to its high molecular weight and the associated high melt viscosity, PTFE can- not be processed using typical thermo- plastic processing methods such as injec- tion molding or blow molding, although it is a representative of the thermoplas- tic material class. In the melting range of approx. +340 °C, PTFE still has a solid, gel- like consistency. For this reason, the press- sintering process is used for shap- ing (→ Fig. 39). Even though sintering processes are ulti- mately based on the melting of solid par- The production of molded parts made of PTFE takes place in several steps: R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 139 X E D N I

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Materials and Process Engineering 1. the PTFE compound is premixed and filled into the mold 2. the PTFE compound is pressed into a green compact at specific pressures > 250 bar 3. the greenling is sintered into a semi-finished product at tempera- tures > +360 °C 4. the semi-finished product is processed mechanically after completely cooling To improve certain properties, fillers are added to the PTFE powders before sinter- ing to increase the hardness of the mate- rial, improve its wear resistance and re- duce the tendency to cold flow. Organic fillers such as glass, carbon, graphite, bronze, molybdenum sulphide and ceramic powder are commonly used. Powdery, high-melting thermoplastics such as polyether ether ketone (PEEK) are also used. The PTFE compound is mechanically sealed at pressures of between 250 and 700 bar. Further processing of these blanks, known as "green compacts," then takes place in special sintering ovens. Here, the green compact is sintered into a homogeneous structure in defined sintering cycles, which are selected de- pending on the PTFE type, the fillers and the wall thicknesses. The usual sintering temperature is between +360 °C and +380 °C. As the individual PTFE particles do not melt, pores remain in the finished product. The pore size can be adjusted very precisely by selecting the starting material used, its particle size and the process parameters. After sintering, the pressed part must be cooled slowly under defined conditions. When the crystallization temperature is reached, the pressed parts shrink consid- erably and can sometimes build up high stresses, which can lead to cracks if they cool down too quickly. After the semi-finished products have cooled down completely, they are ma- chined into foils and punch outs by using machining processes such as turning, drilling or milling or by peeling them into form. The most common processing technolo- gies are listed below: Open tool Fill tool Close tool and press Mold opened – green compacts demolded Fig. 39 Production of hollow cylinders by way of press-sintering 140

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7. From raw material to finished part Press position p Filling position p Cooling PTFE granules Heated extrusion tool (approx. +380 °C) Fig. 40 Principle of ram extrusion y manual press-sintering process for the production of semi-finished products (→ Fig. 39) y ram extrusion for the production of endless rods and tubes (→ Fig. 40) y tableting process – fully automated press-sintering process for the produc- tion of complex molded parts with or without mechanical post-processing y automatic press-sintering process for the production of thin-walled hollow cylinders In ram extrusion, the free-flowing PTFE compound is sealed into the shaping ex- trusion cylinder in batches using a ram. The ram is lifted after a certain time and new powder is metered into the cylinder. Various heating zones along the ram extrusion die ensure that the individual dosing batches are sintered together to form a continuous extrudate. Ram extru- sion is used to produce rod-shaped semi-finished products (solid rods, hollow rods, hoses) quasi-continuously. 7.5 PLASTIC PROCESSING Thermoplastics and thermoplastic elasto- mers such as thermoplastic polyurethane can also be molded into components using a variety of different processes. Classic plastic injection molding is certainly the most widespread alongside extrusion. In contrast to the injection molding of rubber compounds, the injection mold- ing of thermoplastic materials does not include an additional vulcanization step. The main differences between the two I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 141 X E D N I

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Materials and Process Engineering Elastomer → long cycle time → vulcanization Thermoplastic → short cycle time → physical solidification or crystallization +160 °C … +190 °C +60 °C … +80 °C String or strip +30 °C … +70 °C +170 °C … +350 °C Granules recyclable Fig. 41 Comparison of rubber and thermoplastic injection molding IM processes lie in the way the materials are fed, the temperature control and the requirements placed on the molds (→ Fig. 41). In contrast to rubber injection molding, thermoplastic injection molding involves injecting the polymer melt, which has been heated above the glass or melting point, into the cold mold, from which the component can be demolded after com- plete solidification or crystallization. Thermoplastic and TPE melts are generally much thinner than heated rubber mixtures – which is why tools for thermoplastic in- jection molding must be manufactured with significantly higher precision. For further details, please refer to the relevant literature. 142

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8. TESTING METHODS 8. Testing methods Material testing Elastomers must be able to withstand a wide range of stresses in their applications. A wide variety of properties such as strength, setting behavior, abrasion, per- meation or resistance to media are re- quired, which can only map the complex situations of real applications in combina- tion. The user must therefore be able to evaluate these properties neutrally, reproducibly and unambiguously. For this reason, test methods and test procedures are developed, standardized and applied in qualified laboratories such as those of the Freudenberg Group (see also → chapter “Services”, page 7). Freuden- berg laboratories are regularly certified or accredited in order to meet their own high standards. The following chapter is intended to in- troduce the reader to the most common test methods and provide an overview of the test procedures. The use of the test methods goes beyond the mere description of the requirements for the application of the sealing prod- ucts. It begins with raw material control and material development and extends to the processing phase of the compounds, vulcanization and damage analysis in the event of a complaint (→ Fig. 42). The various test methods can be divided into groups that describe their purpose and background. The illustration → Fig. 43 shows a selection of the methods used and classifies them according to the over- riding effects. TESTING OF ELASTOMERS Development: Recipe development Test specimen production Approval Material testing Production: Mixing process Processing process Approval Testing: Vulcanized raw mix Material testing Testing of the finished part Failure analysis: Material testing Testing of the finished part Fig. 42 Testing elastomers I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 143 X E D N I

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Materials and Process Engineering PROCESSING PARAMETERS Cross-linking kinetics Flow behavior Batch variance STATIC-MECHANICAL PROPERTIES Density Hardness Stress/strain (tensile test) DVR tear propagation property Volume change DYNAMIC-MECHANICAL PROPERTIES Frequency behavior Temperature-frequency superposition Fatigue test Tg determination RESISTANCES CALORIC PROPERTIES ELECTRICAL PROPERTIES Storage • Media • Ozone • Light Relaxation Chemiluminescence Thermal capacity (DSC) Thermal conductivity Thermal expansion Surface and contact resistances Dielectric strengths DIFFUSION PROPERTIES TRIBOLOGICAL Gas and liquid permeation Leakage measurements Pore distribution Coefficient of static and dynamic friction Wear measurements Speed-, pressure- and media-dependent tribology studies Fig. 43 Types of tests for rubber PROCESSING CHARACTERISTICS Density Density is one of the most basic param- eters and is determined according to the DIN EN ISO 1183 standard. density of elastomer materials is largely independent of the selected measure- ment method and can be regarded as spe- cific. This is referred to as a "fingerprint method." Material mix-ups can usually be clarified using a density measurement. The individual composition of each raw compound from different base materials makes it easy to differentiate between materials on the basis of density. The Density: p = m  V 144

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8. Testing methods Torque detection with every oscillation Oscillation with variable frequency and amplitude Fig. 44 Schematic structure of a volcametric measuring cell As the degree of cross-linking increases, the torque increases until the cross-link- ing process is complete. The course of the vulcanization can be read off directly. By varying the temperature, the mixture- dependent crosslinking kinetics can be determined and transferred to the pro- duction process. +190 °C +180 °C +170 °C Cross-linking kinetics The speed at which the raw mixture be- comes an elastomer in the hot mold through crosslinking is important from a technical and economic point of view. On the one hand, the raw mixture is no longer capable of flowing after cross- linking begins, so it must therefore have plastically mapped the cavity of the manufacturing tool. On the other hand, the elastomer product should not remain in the subsequent mold longer than necessary in order to avoid reversion effects, for example, and to make it possible to work economically. The vulcanization parameter test is the best way to describe the cross-linking process. A fixed volume of the raw mix- ture is placed between two oscillating, structured chamber halves that are heat- ed to the crosslinking temperature. The measured variable is the time-dependent torque required to carry out the oscillation movement. ] m N [ e u q r o T 0 1 2 3 4 5 6 7 8 9 Time [min] Fig. 45 Rheometer curve I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 145 X E D N I

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Materials and Process Engineering 1ste Newtonian region Shear thinning area Stick-slip Area with possible wall sliding ] s a P [ y t i s o c s V i 1,000,000 100,000 10,000 1,000 100 10 1 1E-03 1E-02 1E-01 1E+00 1E+01 1E+02 1E+03 1E+04 1E+05 1E+06 1E+07 1E+08 1E+09 Shear rate [1/s] Fig. 46 Shear rates Flow behavior Modern injection molding processes re- quire precise knowledge of the behavior of the raw mixture during the injection process. Shear thinning, wall slip, strand swelling and melt fracture are just some of the phenomena that should be de- scribed depending on the material. An ex- ample of this is viscosity, which decreas- es significantly in rubbers over the shear rate (speed at the same channel cross-section). High-pressure capillary rheometry provides reliable measured values for this, which are required to de- sign the vulcanization tools or their flow channels (→ Fig. 46). However, measure- ment technology alone would not be able to adequately describe flow behavior. Only in combination with simulation methods can the measured values gen- erated help to achieve the tool design with minimal reworking. This interplay between a suitable test method, deter- mined characteristic values and suitable simulation tools will be discussed again elsewhere in this chapter. Practical combination of vulcanization and flow behavior In production-related applications, it has proven useful to use a method that forms an intersection of the two methods de- scribed above. With the “Rheovulcame- ter" measuring method, it is not possible to determine exact characteristic values for viscosities or reaction times during 146

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8. Testing methods The individual hardness tests differ accord- ing to the geometric shape of the indent- ers (cone, truncated cone or ball), size and type of load as well as other parameters during the test (measurement duration, contact surface, thickness of the test specimen, distance to the edge of the test specimen, etc.). The local deformation of the material is made up of different parts of compressive, tensile and shear deforma- tions. The determination of the hardness is therefore dependent on the visco elastic properties of the materials. → Fig. 48 shows an overview of the most commonly used methods. There is no linear correlation between the individual methods and it is not possible to convert Shore A to IRHD, for example. Experience shows that for soft, highly elastic compounds, the Shore A and IRHD standard measurement values are almost identical, whereas for materials with higher hardnesses, the IRHD measure- ment results in higher measured values in comparison. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 47 Rheovulcameter: Test device setup and use of the tool 147 X E D N I vulcanization, however comparative tests between different compounds or, in the case of a compound development, the influence of individual components on the flow behavior can be carried out very quickly and meaningfully. An exact amount of raw mix is pressed through a capillary into a defined test tool. If the test parameters are kept constant, the filling level of the tool is an indicator of the quality of the manufacturing process as a whole. Parameters for simulations cannot be determined here. STATIC-MECHANICAL PROPERTIES Hardness test One of the most basic mechanical tests is the so-called hardness test. It is a simple, quick and therefore inexpensive method. In principle, the term "hardness" refers to the resistance of a body (mate- rial) to the penetration of a harder body (indenter) under a defined force. In the case of metals, this creates a plastic im- pression that must be measured after the force has been removed in order to deter- mine the hardness value. As elastomers recover elastically after being deformed by the indenter, the indentation depth is measured here during the application of force. (With plastics, both methods are used depending on the type.) With elastomers, the test basically follows two different procedures. One is the applica- tion of a constant weight force (IRHD) or deformation by a defined spring force (Shore). The hardness numbers represent units derived from the penetration depth and cover a range from 0 to 100 degrees of hardness. The measured values are dependent on the viscoelastic properties, in particular the stiffness or the stress value.

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Materials and Process Engineering Shore A (DIN 53505) IRHD sub-range soft (DIN 53519) 10 10 90 40 35 98 IRHD sub-range normal (DIN 53519) Shore D (DIN 53505) Ball pressure hardness (DIN 53456) 30 90 1.0 48 Fig. 48 Overview of common hardness testing methods for rubber and TPE softer harder hardness y uneven test specimens; the specimen and the measuring device must always be kept parallel Standards: y ISO 48: IRHD (method M describes the microhardness test with a significantly smaller indenter (half sphere 0.4 mm) y ISO 868: Replacement for DIN 53505: Shore hardness Hardness measurements and specifica- tions are generally subject to a fluctuation range of ±3 hardness points due to the system. This information does not take material variations into account. In principle, the hardness tests are carried out on test specimens prepared from so- called test plates (the geometry is deter- mined by the standard). Small residual samples or finished parts can be deter- mined using the microhardness test. The measuring accuracy decreases, however. Areas of application for hardness testing include batch control, undercrosslinking, material mix-up, hardening or softening of the material due to ageing and mate- rial homogeneity. Possible errors are: y sample thickness is too low → leads to higher measured values (standardized thickness: 6 mm). The same applies to excessive contact pressure y measurements are too close to the edge, e.g. if the molded parts are too small → the values are too low 148

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8. Testing methods I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A Tensile strength R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Elongation at break R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P 200 mm/min S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P ] a P M [ i n o s n e T 30 25 20 15 10 5 0 Span value at 300 % 0 100 200 300 400 500 600 700 Elongation [%] Fig. 49 Stress-strain diagram i n o s n e T Steel i n o s n e T High deformation speed Low deformation speed Thermoplastic Elastomer Pseudo-static behavior Fig. 50 Stress-strain diagram. Left: Comparison of steel, thermoplastic, elastomer. Right: Behavior of elastomers at different deformation speeds. Stretching Stretching C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 149 X E D N I

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Materials and Process Engineering Tensile tests After the hardness test, the tensile test is the most widely used test method for elas- tomers. Defined test specimens in rod or ring form are clamped in appropriate clamping or holding devices and stretched at a constant speed until they break. The speed is low and constant; this is referred to as the quasi-static characteristic value (→ Fig. 49). The primary measurement variables are the force required for stretching and the path or distance covered. From this, the variables stress (from specimen geome- try and force) and relative strain (from specimen geometry and displacement) are determined and displayed in the stress-strain diagram. The course of the stress over the elonga- tion is non-linear in elastomers, which is why no modulus of elasticity can be deter- mined. Instead, the stress value deter- mined at a fixed strain (e.g. 50, 100, 200% etc.) is a reliable variable. For elastomers, this value is also referred to as the modulus, e.g. modulus 100 (stress value at 100% elongation). It re- flects the "stiffness" of the material at the corresponding elongation and correlates within limits with the hardness (→ Fig. 50). A C D B Fig. 51 Shoulder bar according to ISO 37 (edition 12-2011) 150 All values determined are characteristic values and not material constants. They are therefore dependent on the test conditions, e.g. specimen geometry and pull-off speed. Tensile tests are carried out as standard on virgin samples, i.e. the test specimen has not previously been subjected to any load. This eliminates the effect of stress softening (Mullins effect), which can occur when products are used later. Elastomers can be regarded as isotropic, which means that their properties are independent of direction if they are manufactured ideally. However, the manufacturing process of the test specimens or their removal from finished parts can lead to orientation of the polymer chains. These effects must be taken into account during testing. The tensile properties are dependent on tem- perature and humidity and must therefore be tested in a standardized climate. Areas of application are the determina- tion of static strength values, quality and batch controls as well as testing the im- pairment of elastomers due to influenc- es during use, e.g. operating media, light, heat and oxygen. When using the values determined for component design, the standardized tensile test can hardly be used, as effects such as changes in entro- py with temperature, stress softening, dynamic hardening and geometric influ- ences are not taken into account. Depending on the standard (e.g. DIN 53504 or ISO 37), the tests are carried out with test rods or rings that are machined from a test plate. The direction of removal must be kept the same. The production of the test plate blank can lead to an anisotropic influ- ence on the actually isotropic elastomer.

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8. Testing methods I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I SHOULDER BAR R O F S L A E S Y R A T O R S N O T A C I I L P P A 75 50 35 12.5 ± 1 8.5 ± 0.5 6 ± 0.5 25 ± 1 16 ± 1 12 ± 0.5 TYPE 1 TYPE 1A TYPE 2 TYPE 3 TYPE 4 DIMENSIONS [mm] Total length A Width of heads B Length of the bar C 115 25 ± 1 33 ± 2 100 25 ± 1 21 ± 1 Width of the bar D 6.2 ± 0.2 5 ± 0.1 4 ± 0.1 4 ± 0.1 2 ± 0.1 Thickness of the shoulder bar 2 ± 0.2 2 ± 0.2 2 ± 0.2 2 ± 0.2 1 ± 0.1 Initial gauge length 25 ± 0.5 20 ± 0.5 20 ± 0.5 10 ± 0.5 10 ± 0.5 Tab. 8 Dimensions of the shoulder bars according to ISO 37 (issue 12-2011) Standards here are, for example, DIN 53504 and ISO 37. Care must be taken to air- condition the samples (→ Fig. 51 and → Tab. 8). Elastomers react sensitively to changes in temperature and possibly also humidity. DIN 53504 specifies a feed speed of 200 m/min for S2, S3 and S3A. Larger bars (S1 and S1A) are tested at a higher speed of 500 mm/min. COMPRESSION SET When it comes to assessing the suitabil- ity of an elastomer as a sealing material, testing the compression set is extremely important. It describes the viscoelastic behavior of elastomers under constant pressure and constant deformation. ISO 815 is one of the most widely used test standards. A cylindrical specimen of a certain height (h0) is compressed by a percentage of its height (standard: 25%). Hard materials are compressed less. In this state, the test specimen is subjected to stress at an increased/decreased tem- perature. The duration and temperature level are regulated by the respective spec- ification or result from the question to be answered (e.g. application temperature). After temperature storage, the specimen is relaxed again, removed from storage and its new height measured. From the initial height, pressed height and height after removal from storage, the percent- age recovery can be determined. If the specimen has almost completely recov- ered, i.e. its height after storage almost corresponds to the initial value, its residual deformation and thus also the compression set is low. If the specimen remains deformed after storage, i.e. its height almost corresponds to the height in the compressed state, the compression set is high. The specified numerical value is a percentage expression of the residual deformation (→ Fig. 52). R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 151 X E D N I

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Materials and Process Engineering Delivery Deformation at constant temperature h0 F F hs Recovery after deformation Calculation of the compression set C h1 C = h0-h1 h0-hs · 100 % Fig. 52 Calculation of the compression set Depending on the instructions, the body is removed from the device before or after cooling and the height (hs) is meas- ured again. The compression set is then determined using the following formula. In addition to being able to make a state- ment on sealing behavior/ageing under operating conditions by using long test times, the compression set can also allow for a statement to be made on the state of vulcanization with short test times. The suitability of the material for static sealing can be determined by measuring the temperature near the glass transition or crystallization points. TEMPERATURE-FREQUENCY BEHAVIOR Elastomers are entropy-elastic materials. The key to this property is the ability of the macromolecules, often called chains in the case of rubber, to move. Their elasticity is based on the tendency of these polymer chains to repeatedly bring themselves back into a "knotted" state (similar to a ball of wool) and increases with increasing temperature. If energy is removed from this system, e.g. by lowering the temperature, the movement of the polymer chains is re- stricted or completely frozen (→ Fig. 53). In this state, the elastic, stretchable material has become a rigid, brittle body that with- stands compressive or tensile stresses with a stiffness higher by several factors, or breaks. The temperature at which the struc- ture transitions from rubbery to glass-hard is called the glass transition temperature. Compared to the very precisely defined melting temperature of water, the glass transition temperature is more of a tran- sitional range in the temperature spec- trum and is heavily dependent on the test method. In the past, many different test methods were standardized to describe the behav- ior of elastomers at low temperatures and to determine the glass transition tempera- ture. The characteristic values determined for the "freezing" of the elastomer differ considerably in some cases and are not systematic (→ Tab. 9). 152

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8. Testing methods The interpretation is therefore by no means simple and must be left to the experts. This is partly due to the fact that the be- havior of elastomers is not only depend- ent on temperature, but that their reac- tion also depends on the speed at which the stress is applied. As already shown in the tensile test, the resistance to a movement increases with the speed at which it is carried out. The explanation can again be found in the macro-molecular structure of the mate- rials. In the event of stretching, the elas- tomer matrix is forced into an external order. The chain structure is brought from the "ideal" ball into a stretched structure. In addition to the effort to re- turn to the lower-energy, free-moving state, energy must also be absorbed to organize the molecular strands when the chains are stretched. The faster the elas- tomer has to perform the movement, the greater the energy required. TEST PARAMETER Gehmann test T100, T10, T5, T2 Cold brittleness TS, TB Temperature retrac- tion test TR10, TR30, TR50, TR100 Torsional vibration test Differential thermal analysis TÜ, TR TR Tab. 9 Different methods for describing the glass transition temperature 10.000 ] a P M [ G 1.000 100 10 1 glass-elastic area rubber-elastic area TG –150 –100 –50 0 +50 +100 +150 +200 +250 Temperature [°C] Fig. 53 Modulus behavior of polymeric materials over temperature Duromer Thermoplast Elastomer I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 153 X E D N I

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Materials and Process Engineering Temperature behavior at constant frequency Frequency behavior at constant temperature glass elastic glass elastic l G s u u d o m r a e h S rubber elastic rubber elastic –150 –100 –50 0 +50 +100 +150 +200 +250 10-4 10-2 100 102 104 Temperature [°C] Frequency [Hz] Fig. 54 Mirror image diagrams of the temperature and frequency behavior of elastomers If the speed is so high that these ordering processes cannot be carried out properly, the chains hinder each other, the move- ment is even prevented. The elastomer then stiffens to the same extent as when it passes the glass transition point and can also break in the process. If the frequency is selected as a measure of the time dependency instead of the speed, the result is a mirror image of the temperature dependency (→ Fig. 54): high frequencies and low temperatures both lead to stiffening of the elastomer. Even in the state of limited mobility, the suitability as a sealing material depends on the respective application and must be determined experimentally. With dynamic mechanical analysis, a method can now be used in which the frequency, amplitude and temperature can be adapted to the load on a seal, mak- ing its behavior easier to predict. If the statement cannot be made directly, the results of a DMA test can at least be used as parameters in a component simulation. INFLUENCE OF MEDIA: STORAGE TESTS One of the main functions of a seal is to separate media. For example, a plug-in coupling sealed with an O-ring separates water from air in the garden, and the seal in the area of a cylinder liner separates coolant from engine oil. In each case, elas- tomeric sealing materials are influenced by the respective medium. For the mate- rial developer and for the user, the key factor is whether the effects are suffi- ciently small so as not to jeopardize the service life of the seal in the application. With regard to the effect of media, a general distinction can be made between physical and chemical influences. In the case of physical interaction or physical "swelling," the medium to be sealed in the elastomer becomes soluble due to 154

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8. Testing methods the chemical similarity (e.g. polarity). If the solubility is high, the additional liquid molecules now present in the elastomer cause the seal to increase in volume (swell). With poorly selected material combinations, the increase in volume can be several 100%, but is completed after a certain time (equilibrium reaction). Caused by the volume change/media ab- sorption, other properties of the sealing material such as hardness, elongation at break and strength as well as damping properties also change. In contrast to chemical interaction or chemical attack, this effect is largely reversible. If the me- dium can be driven out of the elastomer again, the elastomer behaves as it did be- fore the medium was absorbed. A related effect is the extraction of in- gredients from the elastomer into the surrounding liquid. Due to their better solubility in the liquid, constituents of the elastomer diffuse out of the matrix and into the liquid. If the elastomer consists of a significant percentage of these soluble substances, the result can be volume shrinkage, which can lead to leakages in seals due to a lack of compression. If key parts of the elastomer, such as poly- mer chains or crosslinking points, are af- fected by the medium, a chemical attack takes place. In this case, in addition to a superimposed physical absorption of the medium, the ongoing chemical change (e.g. chain degradation) can lead to an in- definite increase in the volume of the elastomer. In addition, embrittlement without further volume increase is also possible. In any case, the process is not reversible. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P ] C ° [ e r u t a r e p m e t g n i t a r e p o m u m x a M i +275 +250 +225 +200 +175 +150 +125 +100 +70 +50 PTFE FFKM FKM FVMQ ACM HBNR ECO TPE-E NBR VMQ PVMQ AEM CR AU SBR EPDM IIR NR 0 20 40 60 80 100 120 140 160 Swelling in reference oil IRM 903 [%] Fig. 55 Heat and oil resistance of elastomers (according to ASTM D 2000) C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 155 X E D N I

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Materials and Process Engineering Temperature and concentration influ- ence both the speed and strength of the observed effects of all three phenomena described. Not just liquids, but also gases can trigger the phenomena described. The selection of the correct sealing ma- terial cannot be made without having knowledge of its behavior under the in- fluence of media. Therefore, the exact de- termination of the phenomena described above plays an important role. In the simplest case, the necessary test specimens (e.g. tensile bars or circular blanks for volume determination, etc.) are placed in a glass vessel in such a way that they are surrounded by a predetermined excess volume of the respective medium. The vessel is stored in the heating cabinet at a defined temperature for various peri- ods of time and the change in the material properties relative to the properties be- fore the start is determined. Such a test must be carried out according to precisely defined parameters, as the normative Media attack Pressure Radiation Heat Oxygen Swelling Shrinkage Temperature Dynamic stress Ozone Wear and tear Friction Fig. 56 Ageing processes 156 basis (e.g. ISO 1817) alone is not sufficient to achieve good reproducibility. Without the appropriate expertise and experi- ence, results are not reliable. This applies equally to the determination of media stability in complex storage conditions such as in pressure vessels, in the vapor phase or with media that change over time and need to be replaced regularly. Low volume swelling of the seal does not pose a risk to the function if the installa- tion space is designed properly. Volume shrinkage, on the other hand, is to be looked at critically. There is no elastomer that meets all requirements for oil resist- ance, heat resistance and cold resistance in equal measure. The ambient medium and the temperature conditions in the application must therefore be taken into account when selecting the right sealing material. The chemical principle "like dis- solves like" applies. This means, for exam- ple, that polar elastomers (e.g. NBR) swell strongly in polar media (e.g. glycol), while non-polar elastomers (e.g. EPDM) are not resistant in non-polar media (e.g. mineral oil). Further information on the suitability of elastomer materials in selected sealing media can be found in the appendix to this chapter (→ “12. Chemical resistance”, page 180). HEAT RESISTANCE, AGING BEHAVIOR Elastomers, like all organic materials, change their properties during use. This is triggered by external influences (such as oxygen, temperature, media, radiation, dy- namic stress, etc.) that affect them during their service life. The generic term is ageing. The extent to which the effects affect the elastomer depends on the duration and strength of the effects. The higher the act- ing temperature, for example, the shorter

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8. Testing methods Exposure to oxygen and temperature O2 Chain dismantling Networking reduction Post-networking Fig. 57 Effects of ageing on the polymer structure the service life of a part. This results in dif- ferent maximum permissible operating temperatures for short and continuous loads for the individual materials (cf. → “4. Understanding Elastomer Formula- tions – Anti-Ageing Agents”, page 109). On the other hand, the limits depend on the suitability of the elastomer and, above all, the base polymer. The properties of the respective polymer class can certainly be improved by skillful compounding. To assess the ageing behavior, the changes in hardness, tensile strength and elonga- tion at break as well as the compression set are usually determined. This is done after storage in a heating cabinet (DIN 53508). Ageing is recorded at an increased temperature and with a shortened test time. Test temperature and actual oper- ating temperature should not differ too much, however (cf. → “14. Common terminology – RGT rule”, page 219). For the entropy-elastic material family of elastomers, it is mainly the changes in their cross-link structure that are decisive during ageing. A distinction is essentially made between three processes: chain scission, the degradation of cross-linking sites and the formation of new cross-link- ing sites, known as post-cross-linking. In the first two cases, ageing leads to sof- tening of the material, which can go as far as making the surface sticky. The lat- ter effect leads to brittleness or is associ- ated with an increase in hardness. From a scientific point of view, all effects occur side by side during ageing. Depending on the strength and speed of the reactions, macroscopic enlargement or hardening occurs (→ Fig. 58). CHEMO-STRESS RELAXATION With the help of the chemo-stress relax- ation test method, ageing processes can be described precisely and the effects mentioned can be investigated. Within certain limits, it is even possible to estimate the service life. This requires testing at several, usually high temperatures. In order to better assess the various chem- ical ageing influences, the measurements I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 157 X E D N I

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Materials and Process Engineering relative tensile stress [%] Material: NBR (peroxide cross-linked) -1 1000/T [K ] 180 160 140 120 100 80 60 40 20 = 0,25 % +100 °C +110 °C +120 °C +100 °C +100 °C cont. Air cont. Air cont. Air discont. Air cont. N2 E = 122 kJ/mol A 3,0 2,9 2,8 2,7 2,6 2,5 2,4 2,3 0 -2 10 -1 10 0 10 1 10 2 10 3 10 2,2 4 10 Time [h] Fig. 58 Service life prediction based on the extrapolation of the measured values of the voltage relaxation are also carried out in nitrogen or in liquid media for comparison. An Arrhenius plot of the results allows extrapolation to long exposure times at lower temperatures closer to the application. For test specimens with a high volume- to- surface area ratio, the diffusion of oxygen or ozone into the elastomer can be a limit- ing factor for the destruction of the elas- tomer matrix and the associated ageing processes. For this reason, thick elastomer components often age much more slowly in practice than thinner components. Ozone ageing is a special form of ageing. The well-known cracking of stretched rubber parts exposed to the weather is mainly caused by the ozone present in the air, but artificial sources such as laser printers or disinfection devices are also responsible for damage. Methods for testing ozone resistance are described in DIN ISO 1431-1. SERVICE LIFE Static permanent load and permanent deformation If an elastomer component is deformed to a constant thickness, a certain amount of deformation remains after relaxation. Determined in the test according to DIN ISO 815 (compression set) and stated as a percentage of the original deformation, this residual deformation is called com- pression set. The deformation is strongly dependent on temperature and duration. At lower temperatures the influence of viscoelas- ticity predominates, at higher tempera- tures the influence of ageing. 158

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8. Testing methods In certain cases, the compression set pro- vides direct information on the function of sealing elements, e.g. for O-rings. How- ever, measurements are often only avail- able for a few ageing times and at one temperature. No service life estimate can be made here. The method of compressive stress relax- ation is better suited for estimating the service life (DIN ISO 3384-1); it specifies the decrease in contact pressure over time of a constantly deformed seal, a criterion that is more important for tight- ness. In addition, this method can be used to determine an actual service life estimate, as shown in the previous section. In combination with the corresponding component simulation, even the areas particularly affected by ageing can be determined and optimized. If rubber-elastic parts are under constant load instead of constant deformation (e.g. main force connection), the defor- mation continues (no limiting stop). This is referred to as creep. Stress relaxation and creep are related phenomena with the same causes. If the test temperatures are below the maximum permissible con- tinuous operating temperature of the base polymers, compressive stress relax- ation and creep follow an approximately logarithmic time law (→ Fig. 58). Dynamic stress, fatigue and attrition The destruction of rubber parts is far more frequently due to dynamic stress than to a single exceeding of the strength or elongation limits. Constant repetitive deformation damag- es the material due to internal friction, which can initially cause small cracks that grow and eventually lead to breakage. This effect is comparable to a paper clip deformed by bending. A single bending process may not affect the strength. But after several bending processes, the ma- terial breaks. Standardized methods for test conditions are defined in DIN ISO 132 and 53533, for example. Wear resistance This property, which is important for fric- tional loads, also depends to a large extent on the operating conditions, such as the type of lubrication, material and rough- ness of the mating surface, sliding speed, slip, contact pressure and temperature. Wear tests should therefore only be car- ried out with the finished product and as close to practical conditions as possible. Material models The mechanical, thermal and dynamic characteristic values determined form the basis for the development of material models. In contrast to metallic and ceram- ic materials, for example, there is no linear relationship between stress and strain in elastomers. Consequently, it is not suffi- cient to use "simple" linear-elastic material models for simulations, but rather special models, so-called "hyper- elastic material non-aged elastomer without ozone protection agent with ozone protection agent Fig. 59 Damage to the elastomer due to exposure to ozone I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 159 X E D N I

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Materials and Process Engineering models," are used for this purpose. In ad- dition to the statically non-linear behav- ior of elastomers, the stiffness of the ma- terial must be taken into account as a function of the load velocity. For this purpose, Freudenberg has developed op- timized material models that remain valid even with large material deformations (> 150%). Additional information from component analyses and ageing tests leads to com- plex simulations that provide a compre- hensive picture of the service life of elastomer seals. Simulations with corre- sponding FEM models are used for the topology and design optimization of me- chanically loaded components, taking into account moderate non-linearities and the safeguarding of the component function. For further information, please contact TSI. Permeation The transport of gaseous or liquid sub- stances through materials in a solid ag- gregate state, known as permeation, is of great importance in a wide range of tech- nical applications. In addition to the well- known phenomenon of compressed air escaping from car or bicycle tires, plastic beverage bottles, for example, should Material Play-circle  Permeation and explosive decompression Adsorption Desorption Diffusion Diffusion Fig. 60 Permeation process 160 also allow as little of the CO2 dissolved in the liquid to escape as possible. The de- mand for ever lighter components and improved sealing and membrane systems to protect the environment requires knowledge of the transport processes in the materials used. For example, CO2 is increasingly being used as an operating medium for air conditioning systems in the automotive sector. Due to the high solubility of CO2 in many elastomers and because of the wide temperature range in which the functionality of the sealing system must be guaranteed, this is an ex- tremely demanding application area for elastomer seals (see also → “9. Damage analysis – Explosive decompression”, page 173). The actual permeation process (from the Latin permeare: to pass through) is divided into three sub-steps (→ Fig. 60): y dissolving the medium in the material y the diffusion of the medium through the material y the desorption of the medium from the material As mentioned earlier, the permeation co- efficient depends on various factors. As a material constant, it depends on the material. In elastomeric materials, the polymer used is the parameter that determines the permeability and must be taken into account in sealing issues, in addition to the suitability of the material (resistance). In addition to the base poly- mers, the filler can also influence the media permeability within certain limits. The material dependence of the perme- ation coefficient at a measuring temper- ature of +80 °C is shown in → Fig. 61 a–d.

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8. Testing methods Influence of temperature on permeation VMQ TPE EPDM FKM PTFE NBR ECO CIIR Test gas: Nitrogen 20 30 40 50 60 70 80 90 100 Temperature [°C] ] ) r a b h ² m m ( / ) m m ) T P N ( ³ m c ( [ P 800 600 400 200 100 80 60 40 20 0 Influence of polymer on permeation Test gas: Nitrogen T= +80°C ] ) r a b h ² m m 1000 100 ( / ) m m ) T P N M V E - V Q P T P E M D M K F E F T P R B N O C E C II R ( ³ m c ( [ P 10 1 0.1 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Fig. 61 Fig. 61a Influence on permeation Fig. 61b Influence on permeation ] ) r a b h ² m m ( / ) m m ) T P N ( ³ m c ( [ P 50 40 30 20 10 0 Influence of fillers on permeation HNBR 10 phr filler 30 phr filler 40 phr filler Test gas: Nitrogen ] ) r a b h ² m m ( / ) m m ) T P N 30 40 50 60 70 80 Temperature [°C] ( ³ m c ( [ P 180 160 140 120 100 80 60 40 20 0 Influence of medium on permeation NBR T= +80°C Nitrogen i O xygen C arbon dioxide H eliu m H ydro g e n Fig. 61c Influence on permeation Fig. 61d Influence on permeation Examples were taken from the various polymer groups, whereby a different mixture structure also leads to different permeation values. Materials with low permeation values, such as chloro-isobu- tene-isoprene rubber (CIIR), ethylene oxide-chloromethyloxirane rubber (ECO) or nitrile-butadiene rubber are contrasted with highly permeable materials such as EPD M (terpolymer of ethylene, propylene and a diene), TPE or VMQ (silicone rubber). Materials made of VMQ stand out here in particular – their gas permeability is around more than an order of magnitude higher than that of all other rubbers. The application temperature also plays an important role in permeation. Depending on the material, the permeation coefficient changes by a factor of more than 10 be- tween +20 °C and +80 °C. The only excep- tions are silicone rubber and Teflon, whose curve gradients are lower. Higher perme- ation coefficients at high temperatures do not necessarily result in a higher coefficient at room temperature. In the case of ECO and FKM (fluororubber), the curves intersect at +50 °C due to the different gradients. In addition to the temperature, the gas passing through also has a significant in- fluence on the permeation coefficient. S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 161 X E D N I

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Materials and Process Engineering Small molecules, such as helium or hydro- gen, migrate through the material faster than oxygen or nitrogen. → Fig. 64 shows an example of the gas type dependency for an NBR material. Other materials be- have similarly, although the ratios be- tween the values of the individual gases can vary considerably. The behavior of elastomers compared to carbon dioxide is quite interesting. Although CO2 is a relatively large gas mol- ecule, the speed at which it migrates through the elastomer is greater than that of helium or hydrogen. This may be due to the chemical similarity of CO2 and the elastomers. The known high sol- ubility of carbon dioxide in the material confirms this assumption. This chapter has dealt with the basic material tests. For special applications, other physical properties such as thermal expansion, frictional behavior, electrical properties, permeability to gases or liq- uids may be of importance. Many of these properties can only be determined in complex special tests. These tests are only carried out if necessary, for example to determine the exact cause in the event of damage. If you have any questions about tests other than those presented, please con- tact the test specialists at FST. 162

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9. DAMAGE ANALYSIS 9. Damage analysis I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I Even if products and components are constructed to the best of our knowledge and taking the latest findings from devel- opment, design and use into account, unexpected damage occurs time and again. It can occur in all product phases (development, storage, production, oper- ation, ...) and is often associated with costly production downtimes and recalls. If people are also at risk, additional dam- age to the company's image is to be feared. Research and development must also in- clude a detailed damage analysis or root cause analysis and the definition of suita- ble remedial measures. VD I 3822 provides a guideline for the systematic processing of damage cases. This guideline was de- veloped by the VD I in cooperation with companies and institutes (including FST) and has been successfully applied at Freudenberg since then. Rubber as a material is a complex subject area, especially in the case of damage anal- ysis, in which interdisciplinary cooperation is of particular importance. The chemical reactions that take place during the vulcan- ization process as well as the emission and absorption of various substances during production, storage and use often make it difficult to interpret the results of chemical analysis methods and physical measure- ments. Furthermore, changes in the cross- link structure and/or the widely cross-linked macromolecules themselves can occur dur- ing use. In addition to chemical and physical analyses, microscopic and radiographic methods are often used to perform damage analysis, in fractographic examinations, for example. Finally, it should also be men- tioned that the method of correct photo- graphic documentation is also part of the basis of efficient damage analysis. 9.1 DAMAGE ANALYSIS PROCESS A systematic approach is essential in damage analysis. At Freudenberg, dam- age analysis is carried out in accordance with VD I guideline 3822. A visualization of the procedure is shown in → Fig. 62 dargestellt. If there is a leak in the system and a de- fective seal is removed, the problem of- ten appears simple, the defective sealing element is assumed to be the cause and submitted for analysis. However, the re- ality is often much more complex. In or- der to successfully drive the damage anal- ysis forward, it is necessary to take a holistic view of the failure process and Damage description Inventory of damage Damage hypothesis(es) Instrumental analysis Result evaluation and interpretation Cause(s) of damage Remedial measure(s) Damage report Evaluation Failure analysis Management system R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 62 Damage analysis process 163 X E D N I

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Materials and Process Engineering Causes of errors F a u m l t y a t e r i a l c s i e g s s i n g n F F M F a a a u u u e p r l t d l t l o c h l t e h a o y y a a n d y n d i c l i a n l g Tribological stress Climate-stress Media-related stress Thermally induced stress Mechanism of the error Other problems Description of the error General evaluation Fig. 63 Ishikawa diagram for formulating possible damage hypotheses the product - from development to inter- mediate steps such as production and quality control (and much more) through to the application with all its influences. It often makes sense to involve experts from the fields of material, process, design and application technology. The first step in describing damage is documentation with the help of images and sketches. If samples are destroyed in further analyses, the original condition can be viewed again, at least virtually, retrospectively. This includes a descrip- tion of the samples with all of the abnor- malities such as cracks, deformations, discolorations, etc. Finally, more detailed macroscopic examinations are used to document and evaluate characteristic damage phenomena in order to determine whether the same damage mechanism is present in all samples. Information on the samples and the accompanying cir- cumstances is collected in the inventory. This includes the product phase (field failure, development, test bench), the product history (how long has the product existed? Are similar failures known?) and the failure history (number of failed parts, localization of the dam- age?), see also → chapter “Services” from page 7). Finally, one or more damage hypotheses are drawn up using the information from the damage description and inventory as well as knowledge of damage mecha- nisms and experience from other damage cases. The Ishikawa diagram shown in → Fig. 63 serves as a template for formulating the damage hypotheses. The damage hypotheses serve as a guide- line for the analyses. Particularly in the event of damage, it is important to choose the sequence, location and type of preparation and analysis methods carefully. In addition to the failed products, new and good parts are always required for comparative analyses. Map-Marker-Exclamation Services and Consulting 164

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9. Damage analysis Close cooperation within the interdisci- plinary team is required when evaluating and assessing the results with regard to the claim. If results do not confirm the hypothesis or unexpected results occur, the analysis plan must always be flexible enough to allow other methods to be used for verification. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P DESIGN ERRORS MECHANICAL THERMAL LOAD LOAD MEDIA EXPOSURE CLIMATIC STRESS S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 165 X E D N I MANU- FACTURING ERRORS Vulcanized elastomer particles MATERIAL ERRORS Material mix-up Wrong raw material quantity Contamination of raw materials or the compound Slit extrusion Cracks Cracks Swelling Hot cracks Offset Delamination Cracks, tears Malfunction with an undamaged component Softening Scratches/ scoring Geometry changes/ permanent deformation Extraction Replacement of additives with compo- nents of the medium Oriented cracks due to ozone exposure Non-oriented cracks due to exposure to UV light Frosting Insufficient mixing Gas bubbles Air/gas inclusions Abrasion/wear Hardening Reaction of additives with media Softening, hardening, stickiness Use of incorrect- ly stored or expired raw materials or compounds Flow errors Flow errors Charred surface Incompatibility of components Under-/over- vulcanization Color change Cracks with crack exit in the material interior Softening, hardening Porosity, cracks Tab. 10 Common damage phenomena and causes

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Materials and Process Engineering 9.2 TYPICAL DAMAGE PHENOMENA, CAUSES AND MECHANISMS Some common damage phenomena and causes are summarized in → Tab. 10. At first glance, it is clear that many damage phenomena (e.g. cracks, hardening, softening) can have different causes. For example, a component with many small cracks may have been damaged both by mechanical impact and by ozone expo- sure. This shows that damage patterns are often deceptive and an analysis can- not be carried out on the basis of the first visual impression alone. The relevance of the phenomena found must always be assessed when determining the cause of damage. In other words: Is a phenomenon the cause of the failure, a contributing factor or not the cause? Some of the typical damage phenomena and their underlying mechanisms are ex- plained below using selected examples. MATERIAL DEFECTS During compounding, the raw rubber and additives such as fillers, plasticizers, cross-linking chemicals, anti-ageing agents and much more are brought together. This is followed by the shaping and vulcaniza- tion process. Material defects are consid- ered here to be defects that are caused by compounding, transportation and storage of the elastomer mixture. Par- ticularly in non-certified mixing plants, materials may be mixed up or additives may be added incorrectly, which can result in deviations in the properties of the material from the specification. Contam- ination of the raw material or compound during transport, storage and processing is also possible. Examples of this are shown in → Fig. 64 and → Fig. 65. The de- fects shown can have an optical effect (if the contamination is visible on the surface of the component), lead to defects such as cracks or, depending on the application of the product and the size of the contamination, cause no change in properties. Unfortunately, it is not possi- ble to make a general statement on the probability of damage based on particle sizes. Whether an inclusion causes a crack depends not only on its size and compo- sition, but also on the environmental con- ditions (component geometry, load, etc.). Fig. 64 SEM image of a metal particle (light) in the elastomer matrix Fig. 65 Microscopic image of a fiber on the surface of a light-filled vulcan- izate 166

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9. Damage analysis Map-Marker-Exclamation “Zero-defect strategy” in the manufacturing process Fig. 66 Poor carbon black distribution Fig. 67 Good carbon black distribution Another example of material errors is insufficient mixing. The effects this can have are shown in → Fig. 66 and → Fig. 67. For this purpose, the starting materials specified in a formulation were mixed in two batches, but with different mixing times. After vulcanization, cold thin sec- tions were prepared and microscopically examined under transmitted light (the dark spots are carbon black agglomerates). As mentioned above, elastomeric mate- rials are made up of a wide variety of components that are not always compat- ible with each other. This can lead to the finely dispersed components in the mix- ing process later coalescing into larger domains (coalescence) or migrating out of the mixture and causing a change in the physical properties. In the case of some ingredients, this is quite desirable, if, for example, anti-ageing agents migrate to the surface of the product and protect the component there through a chemical reaction. However, this can lead to com- plaints in applications with contact to foods or visually demanding components. MANUFACTURING ERRORS When manufacturing and selecting the appropriate sealing solutions, the utmost care must be taken in order to meet the most diverse requirements of the many different areas of application. This makes it all the more important to have a compe- tent partner who already safeguards the highest quality during the manufacturing process with a "zero-defect strategy." Freudenberg Sealing Technologies has been pursuing precisely this approach for many years and is therefore in a position to supply you with the best and faultless quality in the field of sealing technology – precisely tailored to your requirements. Despite all due care, errors can occur during the manufacturing process, e.g. during shaping, vulcanization or post- processing, which are discussed below. Errors can only be recognized and avoided through knowledge of possible sources of error. Binding seam Confluence points in the mold can develop into visually visible defects, so- called weld lines. This can be caused by inadequate process parameters (e.g. in- sufficient filling volume, excessively high compound or mold temperature), but also by foreign substances or release agents. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 167 X E D N I

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Materials and Process Engineering elastomer matrix. An example is shown in → Fig. 70. Such a defect pattern is caused by too long a mixing or storage time, too high a compound or tool tem- perature or dead spaces in tools or burrs from previously produced parts. Over- or under-cross-linked material If the vulcanization conditions are not selected correctly or the quantity of cross-linking chemicals is not optimal, this leads to deviations in the material properties from the target state or spec- ification. In particular, deviations in the vulcanization temperature or in the tem- perature distribution within the mold quickly lead to defects. It must be en- sured that the vulcanization conditions are correct at all times. The temperature sensitivity of a peroxide cross-linked HNBR compound is shown here as an example. Even a temperature change of +10 °C can result in a 30 % lower degree of polymerization. The physical and ageing properties can change fundamentally. Hot cracks → Fig. 71 shows examples of the me- chanical properties of a vulcanizate in dif- ferent temperature ranges. The signifi- cant change in strength and elongation at break at higher temperatures can be a potential source of error. When the mold is opened after vulcanization, expansion or tensile forces can lead to so-called hot cracks in the component. The resistance to mechanical influences is massively reduced. Sharp edges can also cause damage here. Bubble formation Insufficient venting of the material during filling or residual moisture in the rubber Fig. 68 Binding seam: top view under a scanning electron microscope Fig. 69 Binding seam: Macroscopic image of a thin section in transmitted light Fig. 70 Scorched elastomer particle (macro- scopic image of a thin section in transmitted light) Vulcanized material If elastomer particles were already vulcan- ized in the mold before the actual manu- facturing process, they do not or only in- sufficiently crosslink with the surrounding 168

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9. Damage analysis s e i t r e p o r p l i a c n a h c e M 75 A 180% 21 MPa Hardness Elongation at break 60 A 60% Tensile strength 3,5 MPa -50 0 RT 50 100 150 200 250 Temperature [°C] Fig. 71 Mechanical properties at different temperatures compound itself lead to the formation of bubbles during the manufacturing process. The air can also be pushed in front of the flow front and collect in the area of the confluence point. Bubbles, porosities or smooth indentations form along the sealing surface. The phenomenon of gas bubble formation occurs primarily with large-volume components. Delamination In the case of delamination damage, the elastomer material has a layer-like sepa- rated structure (flaky). Possible causes in- clude air inclusions (→ Fig. 73), especially in the case of gas-tight elastomers or large-volume components, release agents or foreign material between the flow fronts (→ Fig. 74). Fig. 72 Gas bubbles in the cross-section of Fig. 73 Delamination (Image: Freudenberg a voluminous component Technologie Innovation, order) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 169 X E D N I

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Materials and Process Engineering Fig. 74 Delamination (VDI guideline for production, Freudenberg Technol- ogie Innovation) Fig. 75 Oﬀset Material testing Oﬀset Tool parts are worn or incorrectly fitted and no longer close symmetrically. This results in the formation of a shoulder in the parting line area. Errors in tool dimen- sioning (design errors) can also cause this form of damage. Despite an otherwise perfect condition, the component often cannot perform the sealing task. DESIGN ERROR Gap extrusion Gap extrusion is the migration of the seal into the sealing gap facing away from the pressure side. This type of damage also occurs, for example, due to design errors in the sealing gap, if there is too little opportunity for temperature expansion or if there is too much volume swelling. In Pressure p Pressure p Fig. 76 Principle sketch of gap extrusion 170 the static case, this leads to the formation of the typical extrusion flag shown in → Fig. 77. Under dynamic load, the elas- tomer is "nibbled off" (→ Fig. 78). Errors in the choice of material (insufficient deformation resistance) or the ingress of media into the material can also cause or promote the damage phenomenon. MECHANICAL STRESS According to the VD I guideline for damage analysis VD I 3822, sheet 2.2.5, damage caused by mechanical stress includes damage that occurs during use or assem- bly. In addition to the type of load (ten- sion, compression, torsion, buckling, etc.), the loading speed is important, especially at low temperatures (see also "thermal load"). If the material cannot follow the movement of the limited components, this can lead to leakage of the system or, in a glass-hard state, to the destruction of the component. Mechanical overload/fatigue Even if a mechanical load under cyclic stress is far below the maximum elonga- tion and strength of the material, the mechanical properties will change as a result of permanent swelling stress. This

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9. Damage analysis Fig. 77 Gap extrusion – static application Fig. 78 Gap extrusion – dynamic application is referred to as fatigue. This results in chain fractures on a microscopic level or, on a macroscopic level, many small cracks in the material, which can ultimately lead to failure. Permanent deformation or abrasion can also occur as a result of dynamic stress. Mechanical injury Scratches, scoring and cracks are often caused by sharp edges or unsuitable tools, during removal from the mold, for example. Exemplary damage patterns for mechanical damage are shown in the SEM images in the following figures (→ Fig. 79 und → Fig. 80). Abrasion The importance of the individual design of seals is shown by the abrasion behavior when the surface quality changes. Even the smallest changes in the surface treat- ment method can result in premature fail- ure of a seal. It is therefore highly inadvis- able to simply transfer a sealing solution. Cleanliness is also the top priority during assembly, as chips, dust and dirt can lead to the same effect and thus have an enor- mous impact on the longevity of the seal. In general, it can be said that although there are special formulations for elasto- mers that show improved abrasion be- havior, only lubrication prevents rapid wear in dynamically used seals. Twisting This fault pattern describes cracks in the seal caused by torsional stress. If the seal is twisted, it tears after frequent load changes. This is caused by a dynamic load in which one side of the seal remains immobile or slides, while the other side adheres and is thus twisted. Frequent changes of direction in particular lead to material fatigue – the seal shows typical spiral cracks. Here it is important to avoid possible eccentricity, i.e. the distance be- tween the center of the groove and the symmetry axis of the component. Eccen- tricity causes uneven load points, e.g. in the event of pressure fluctuations, which increases the probability of twisting. Good surface quality and good lubrica- tion conditions also help. In addition, the effect may occur less frequently with thicker cords (see also → chapter „Static Seals – 11. Technical Support – Twisting“, page 625). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 171 X E D N I

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Materials and Process Engineering Chemical media Biological media Radiation ? Temperature Natural load Mechanical load THERMAL STRESS Low temperatures → Fig. 81 shows the behavior of the elas- tomer, thermoplastic and duromer materi- al classes schematically over temperature. Elastomers are solidified like glass below the glass transition temperature (Tg). In this area, even low loads can lead to failure through breakage. In addition, the modulus increases sharply even before the glass transition point is reached, so that a change in resistance during excitation of dynamic seals or diaphragms is to be expected. The entropy-elastic behavior typical of elastomers can be seen above the glass transition. This is the actual area of appli- cation for elastomer materials. However, the material does not only stiffen when the temperature is lowered. Even at temperatures above the glass transition Fig. 79 Damage pattern for mechanical Fig. 80 Damage pattern for mechanical damage, SEM image damage, SEM image 172

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9. Damage analysis temperature, high deformation speeds can result in the polymer chains not being able to follow the deformation quickly enough. In addition to catastrophic failure, this be- havior also leads to other malfunctions such as leakage. This is shown in → Fig. 84 using the sealing function of an O-ring. The O-ring can follow a dynamic load/ opening of the mating surface at room temperature quickly enough and prevent a gap from developing. If the same happens at temperatures close to the glass point (or at very high frequencies), the mobility of the polymer chains is restricted to such an extent that the seal cannot follow suf- ficiently quickly and leakage can there- fore occur. High temperatures and media stress See → “Heat resistance, aging behavior”, page 156. EXPLOSIVE DECOMPRESSION If the seal is destroyed by a sudden drop in high gas pressure acting on the seal, e.g. due to a pipe bursting, this is known as explosive decompression. This type of damage is caused by gas dissolved in the seal. The higher the gas pressure, the greater the amount of dissolved gas in the seal. If there is no counter-pressure (e.g. due to a pressure drop in the system), the dissolved gas strives to leave the seal, similar to the carbon dioxide in a bottle of water. In the elastomer, this process is linked to the diffusion speed, and there- fore only takes place slowly. If the result- ing internal pressure exceeds the strength of the material, destruction occurs due to the formation of bubbles or cracks in the seal. The larger the volume of the compo- nent in relation to its surface area, the more likely it is that the defect will occur. 10.000 ] a P M [ G 1.000 100 10 1 glass-elastic area rubber-elastic area TG –150 –100 –50 0 +50 +100 +150 +200 +250 Temperature [°C] Fig. 81 Modulus behavior of polymeric materials over temperature Duromer Thermoplast Elastomer I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 173 X E D N I

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Materials and Process Engineering Play-circle  Permeation and explosive decompression Fig. 82 Damage due to excessive mechan- ical stress at temperatures close to the glass transition The error depends heavily on the material and type of gas. CLIMATIC STRESS Hydrolysis Hydrolysis is the cleavage of a chemical bond by the presence of water molecules. In the process, hydrolysis-sensitive groups such as esters, amides, etc. are cleaved. As a result, the polymer chains are broken down and the material properties are changed. In the presence of acids and bases, the process is catalyzed, i.e. accelerated. As acid groups are formed during hydrolysis, these accelerate further by autocatalysis. +23 °C 0 °C Fig. 84 Temperature-dependent reset behavior (from VDI Standard 3822, Part 2.2.7) 174 Fig. 83 Damage pattern for explosive decompression The reaction rate increases at higher tem- peratures. Furthermore, at higher tem- peratures, more moisture can be ab- sorbed from the air, which can also lead to accelerated hydrolysis. This effect is par- ticularly significant for plastics (e.g. polyes- ter, polyamide ....) and polyurethanes. Elas- tic materials are less affected. Exposure to UV light High-energy light leads to changes in the polymer chains of the materials. Elastomers that contain double bonds in the main chain (R family) are particularly susceptible. Compared to translucent plastics, which are also damaged within their volume, elastomers often only suffer damage in the area near the surface due to their filler con- tent. When components are stretched, surface cracking occurs perpendicular to the direction of loading. In contrast to damage caused by ozone, however, fine non-directional crack structures also oc- cur, and without pre-exposure only these. One speaks of a so-called weathering skin (crazing, "elephant skin"). Softening or hardening of the surface can also occur, especially in the presence of acid. Even if the defect initially only occurs on the surface, classic "tearing," which is known

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9. Damage analysis Fig. 85 Surface changes due to light or UV radiation at different magnifications to require lower forces, can lead to the destruction of the elastomer parts. Color changes due to light can also occur. Exposure to ozone Elastomers with an unsaturated main chain are susceptible to a special form of oxygen molecule, ozone, as well as being less resistant to atmospheric oxygen. A hardened layer forms on the surface. When polymer chains are under mechan- ical tension, chain scission occurs with the formation of carbonyl oxides and car- bonyl compounds. Macroscopically, the cleavage of the molecular chains leads to the cracks that are typical of ozone expo- sure and run perpendicular to the direc- tion of elongation. The ozone molecule attacks in the area of the double bond (→ Fig. 88), whereby a so-called primary ozonide forms first. The unstable ring structure rearranges to form the ozonide in the unstressed state. Cracking occurs above a certain critical elongation (depending on the material and environmental conditions) and is in- tensified with increasing elongation of the elastomer (→ Fig. 87). 5% no cracks 10% cracks 20% cracks 25% cracks n o i s n a p x e f o n o i t c e r i D Fig. 86 Oriented cracks caused by ozone exposure (image Freudenberg Technologie Innovation) Fig. 87 Ozone cracks due to expansion stress I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 175 X E D N I

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Materials and Process Engineering Attack on a double bond R1 H C = C R2 R2 Rubber (O3) + O + O – O W ith o ut stretc hin g O O O R1 R2H R2 Primary ozonide With stretching Fig. 88 Ozonization R1 R2 O H O R2 O Ozonide (hardened layer – crazing) R1 H C = O – O + O + C(R2)2 Cracking with “critical elongation” 176

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10. DEFECT CHECKS 10. Defect checks Defect checks are common in the sealing industry, whereby a distinction is made between manual and machine checks. However, the advantages and disadvan- tages of both options must be taken into account. Manual inspection may allow for more intensive testing of the component, but can be subjectively influenced. If the in- spection intervals are too long, there is also a risk of material fatigue. A machine-based test is also not 100% er- ror-free, as the boundary between passing and failing must be defined beforehand. If this is too low, more faulty parts reach the customer; if the limit is too high, the pseudo scrap increases. Another disadvantage of automatic con- trol is that faults have to be taught in. Skilled personnel are more flexible in this respect when it comes to new error pat- terns. Inspection is primarily possible for exter- nally visible defects (surface). Other pos- sibilities: X-ray, CT, density, measurements, etc. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 177 X E D N I

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Materials and Process Engineering 11. PROPER STORAGE The correct storage of elastomer compo- nents has a major influence on their durability and is therefore just as much a part of handling as proper assembly and installation. Components can be damaged by improper storage, which in the case of seals can lead to premature or immediate failure of the seal. STORAGE CONDITIONS The storage temperature must be below +25 °C; the elastomer molded parts must be stored away from direct heat sources and may not be exposed to direct sunlight. Care must also be taken to ensure that the humidity does not lead to condensation when the temperature in the storage room changes. The effects of light, UV ra- diation, ozone and ionizing radiation must also be ruled out. Packaging Materials for packaging such as containers, bags or films may not contain any sub- stances that promote premature ageing of the components. On the other hand, the packaging may not absorb any of the elas- tomer's ingredients. Suitable packaging materials include lami- nated kraft paper, aluminum foil or opaque PE film (min. 0.075 mm thick). The packaging must be labeled as follows so that the parts can be precisely assigned later if necessary: y Part/article number O-ring manufacturer y Description of the polymer 20-2/335674 72 NBR 872 y Quarter and year of manufacture of the elastomer part 1/22 y Classification of the elastomer Group 2 10 pieces Freudenberg (→ Tab. 11) y Number of packages y Name or trademark of the manufacturer Elastomer products are divided into three groups based on their maximum permis- sible storage time (→ Tab. 11). Extensions to the storage period are pos- sible under certain circumstances, but always require consultation with the rele- vant specialist department that will carry out the necessary checks and ultimately 1. STORAGE TIME IN YEARS 1. EXTENSION IN YEARS Group 1 NR, AU, EU, SBR Group 2 Group 3 NBR, HNBR, ACM, AEM, XNBR, ECO, CIIR, CR, IIR FKM, VMQ, EPDM, FVMQ, PVMQ, FFKM, CSM Tab. 11 Recommended storage times for elastomers 5 7 10 178 2 3 5

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11. Proper storage Map-Marker-Exclamation Only one-time extension for shaft seals decide whether the products can continue to be used or must be disposed of. Caution! Only one extension is permit- ted for shaft seals, after which the parts must be scrapped. SUGGESTIONS FOR THE ASSESSMENT OF ELASTOMER COMPONENTS AFTER THE INITIAL STORAGE PERIOD y Testing according to the respective product specification There are product specifications that provide for certain tests after the expiration date. If the corresponding product specification does not contain such information, the following check is necessary: y Visual inspection Each part or component in a repre- sentative sample is to be checked for the following characteristics: • Changes in the condition of the sur- face, such as hardening, softening, stickiness, discoloration or soiling • Additional tests: Microhardness, density, functional dimensions: sealing lip, dust lip, inner diameter and radial force The tested characteristics of the stored parts or components must be document- ed in an appropriate manner. If the number of measured components permits, the reasonable confidence interval around the mean value of each test performed must also be specified. y Each recording must contain the fol- lowing information: • the number of parts or components stored, the date of first packing, the date of loading • the date of each subsequent repack- aging • the manufacturer's batch number, • Permanent deformation, such as if available folds or flat spots • Mechanical damage, such as cuts, cracks, abraded areas or detached layers • Crack formation on the surface, ob- served under a magnifying glass with 10x magnification • the number of parts or components that have been tested I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 179 X E D N I

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Materials and Process Engineering 12. CHEMICAL RESISTANCE The information contained in the follow- ing table has been compiled on the basis of our own tests, recommendations from our suppliers and reports from our cus- tomers. The latest version of this summa- ry can only be found on our homepage. This information can only serve as a rough guide. It is not readily transferable to all operating conditions. Even within the material classes, there can be serious differences due to different mixture com- positions. Given the large number of factors affect- ing the seals and molded parts, chemical resistance is a very important but only a partial aspect of the overall operating conditions. The following factors should always be taken into account when se- lecting Freudenberg Sealing Technologies materials and the shape of the sealing element: y heat and cold resistance y static or dynamic load y type of material of the machine parts to be sealed The elastomers listed in → Tab. 12 are named with their chemical designations and the abbreviations defined in ASTM D 1418. ELASTOMERS LISTED IN THE RESISTANCE TABLES ACM Acrylic rubber AU CR Polyurethane Chlorobutadiene rubber CSM Chlorosulfonated polyethylene EPDM Ethylene propylene diene rubber FFKM FKM Perfluoro rubber Fluororubber FVMQ Fluorosilicone rubber HNBR Hydrogenated acrylonitrile butadiene rubber y surface quality of the metal parts or IIR Butyl rubber plastic parts y for rotating seals: Speed y for axially moving parts: Stroke length and stroke speed y for other dynamically loaded seals: Load frequency and amplitude If no special information is provided in the tables, commercial and the usual purity, concentration and specified tempera- tures for the respective media are to be assumed. In case of doubt, especially for untested or new applications, we recom- mend that you consult us so that special tests can be carried out if necessary. NBR Acrylonitrile butadiene rubber NR Natural rubber PTFE Polytetrafluoroethylene SBR Styrene-butadiene rubber VMQ XP Silicone rubber Fluoroprene XP Tab. 12 Material abbreviations Chemical Resistance Guide 180

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12. Chemical resistance In this table and in the following resist- ance overviews, some common elastomer types are missing, e.g. BR, ECO, CIIR, BIIR, EVM, AEM and PVMQ. Analogies are possible in many cases. Fluoroprene XP is a class of premium sealing materials from Freudenberg Sealing Technologies. If you have specific questions or uncer- tainties, please consult the relevant spe- cialist department. The tables on the following pages com- pare the materials listed in → Tab. 12 with regard to their resistance to media at the respective test temperature (col- umn 2). You can find the latest information on resistance online in our Chemical Resist- ance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 181 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Acetaldehyde with acetic acid, 90/10% Acetamide Acetone +20 D G D C C B D D D C D C B C D F +20 G G G F F B G F F F F G B G G F +20 D D D F B B D D D B D B B B D F Acetophenone +20 G G G F F B G G G F G G B G G F Acetylene Acetic ester Acetic acid, aqueous, 25 to 60% +60 B F B B B B B B B B B B B B B B +20 G G G C C C D G D F D D B D G G +60 G G G B B B G G D B D D B D G B Acetic acid, aqueous, 85% +100 G G G F F B G G D F D D B D G B Acetic anhydride +20 G G B B B B D G D B D C B B G C Acetic anhydride +80 G G C F F C D G D F D D B C G F Acrylonitrile +60 G G D G F B D D D D D D B D D F Acrylic acid ethyl ester +20 D D G G F B D D D C D G B G D F Adipic acid, aqueous +20 F F B B B B B F B B B B B B F B Air, oily Air, pure Aircraft engine fuels JP3 (MIL-J-5624) Aircraft engine fuels JP4 (MIL-J-5624) Aircraft engine fuels JP5 (MIL-J-5624) +80 B B B B D B B B B D B D B C B B +80 B B B B B B B B B B B B B B B B +20 C C D D D B B B C D B D B D D B +20 C C D D D B B C C D B D B D D B +20 C C D D D B B C C D B D B D D B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 182

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12. Chemical resistance MEDIUM Aircraft engine fuels JP6 (MIL-J-25656) °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X +20 C C D D D B B C C D B D B D D B Alum, aqueous +60 G D D B B B B G D B D C B C G B Alum, aqueous +100 G G B B B B B F B B B D B B F B Allyl alcohol +80 G D C C B B D G C B C B B B G F Aluminum sulfate, aqueous +60 G D C B B B B F B B B B B B F B Aluminum sulfate, aqueous +100 G D C B B B D F B B B C B B F B Ammonia, 100% +20 G D C B B C D G C B C B B B G G Ammonia water (ammonia) +40 D D C B B B D C B B B B B B C F Ammonium acetate, aqueous +60 G D C B B B D F B B B B B B F F Ammonium carbonate +60 G D C B B B D F B B B B B B F F Ammonium chloride, aqueous +60 G D C B B B B F B B B B B B F B Ammonium fluoride, aqueous +20 G G C B B B B B B B B B B B B B Ammonium fluoride, aqueous +100 G G C B B B D F B B B D B B F F Ammonium nitrate, aqueous +60 G D C B B B B F B B B B B B F B Ammonium nitrate, aqueous +100 G G C B B B D F B B B D B B F F Ammonium phosphate, aqueous +60 G D C B B B D F B B B B B B F F B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 183 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Ammonium sulphate +60 G D C B B B B F B B B B B B F B Ammonium sulphate +100 G D C B B B D F B B B D B B F F Ammonium sulphide, aqueous Ammonium sulphide, aqueous Amyl acetate Amyl alcohol Aniline +60 G D C B B B B F B B B B B B F B +100 G D C B B B D F C B C D B C F F +20 G G G F B B D G D B D B B D G F +60 G D C B B B D F C B C B B B F F +60 G D D G G B D D D G D D B D D G Aniline chlorohydrate +20 G D C C C B B F C C C D B D C B Aniline chlorohydrate +100 G D F G G B G G D G D D B D G G Anisole Anon Anthraquinone sulfonic acid, aqueous +20 G G D G G B G G D G D D B D G F +20 G G D G D B G G D D D D B D G B +30 G D G B B B G G C B C B B B G B Antifreeze (automotive) +60 G D B B B B B B B B B B B B B B Antimony chloride, aqueous +20 B G B B B B B B B B B B B B B B Antimony trichloride, anhydrous +60 G G C B B B G G B B B B B B G F Aqua regia +20 D D D D D B D D D D D D B D D F B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 184

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Arsenic acid, aqueous +100 G G C B B B D F B B B D B B F B Arsenic acid, aqueous +60 F D C B B B B F B B B B B B F B Asphalt ASTM fuel A ASTM fuel B ASTM fuel C +100 F G G G G B F G G G G G B G G B +60 C B C C D B B B B D B D B D D B +60 D D D D D B B B C D C D B D D B +60 D D D D D B B C D D D D B D D B ASTM oil no. 1 +100 B C B D D B B B B D B D B D B B ASTM oil no. 2 +100 B C C D D B B B B D B D B D B B ASTM oil no. 3 +100 B C C D D B B B C D B D B D C B ATE brake fluid +100 D G C G B F D B D B D B B B B F ATF oil +100 D C C D D B B B B D B D B D C B Battery acid (sulphuric acid) +60 G D D B B B B G D B D C B C G B Barium hydroxide, aqueous +60 G D B B B B B F B B B B B B F B Barium salts, aqueous +60 G D C B B B B B B B B B B B B B Beef tallow emulsion, sulphurized +20 G G C B D B B C B D B D B D C B Beer +20 B B B B B B B B B B B B B B B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 185 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Benzaldehyde, aqueous +60 G D D G C B B G D C D C B C G B Benzoic acid, aqueous +60 G D C B B B B B B B B B B B B B Benzene +20 D D D D D B C C D D D D B D D B Benzyl alcohol +60 G D G F F B G C G F G F B F C B Biogas Bisulfite lye Bitumen Black liquor +20 F C B B G B B D B G B D B D B B +50 G D C B B C G F C B C B B B F C +60 G G D G G B B G D G D G B G G B +100 G G C B B B B G C B C C B C G B Blast furnace gas +100 B F C C C B B B C C C D B C B B Bleaching lye +60 G D C B B B C G D C D D B C G B Bone oil +60 B B D D D B B B B D B D B D C B Borax, aqueous +60 G D C B B B B B B B B B B B B B Boric acid, aqueous +60 G D C B B B B B B B B B B B B B Brake fluids (glycol ether) +80 D G C F B F G B D B D B B B B F Bromine, liquid +20 G G D C F F G G D F D D B D G G Bromobenzene +20 G G G G G F F F G G G G B G G F Bromine vapors Bromine water, cold saturated +20 G G D C F F G G D F D D B D G G +20 G G D C F F G G D F D D B D G G B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 186

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12. Chemical resistance MEDIUM Bunker oil Butadiene °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X +60 F G G G G F F F C G C G B G G F +60 G F C D D B B B F D F D B D C B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Butane, gaseous +20 B B C D D B B B B D B D B D F B Butanediol, aqueous +20 G F C B B B C F B B B B B B F B Butanediol, aqueous +60 G D B B B F F F B B B C B B F F Butanol, aqueous +20 C B D B B B C B C B B B B B B B Butanol, aqueous +60 G D C B B B G F D B D B B B F B Butynediol +20 G B C B B C C F B B B B B B F C Butter Butter +20 F B B G G B B B B G B G B G B B +80 F F C G G B B F B G B D B D F B Butyric acid, aqueous +20 G F C F F B B F B F B D B F F B Butyl acetate Butyl acetate Butyl alcohol +20 G G D D C B D G D C D C B D G G +60 G G D D D B D G D D D D B D G D +60 G D C B B B G F D B D B B B F B Butylene, liquid +20 F B C G G B B B B G B D B D F B Butylene glycol +60 G B B B B B C B B B B B B B B B Butylphenol +20 D D D D D B C G D D D D B D D B Butyraldehyde +20 G G G C C C G G G C G C B C G B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 187 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Calcium bisulfite, aqueous +20 G B B B B B B F B B B B B B F B Calcium chloride, aqueous +100 G D B B B B B B B B B D B B B B Calcium hydroxide, aqueous +20 G D B B B B B B B B B B B B B B Calcium hypochlorite, aqueous +60 D D C B B B C G D B D D B D G B Calcium nitrate, aqueous +40 G G B B B B B B B B B B B B B B Calcium phosphate, aqueous +20 G F B B B B B B B B B B B B B B Camphor Camphor oil +20 G G C D D B C G B D B D B D G B +20 G G D C D B C G C D B D B D G B Carbon dioxide, dry +60 B F B B B B B B B B B B B B B B Carbon disulphide +20 G D D C D B B G D D D D B D D B Carbon oxide, moist +20 B G B B B B B B B B B B B B B B Carbon oxide, dry +60 B B B B B B B B B B B B B B B B Carbon tetrachloride +60 G G D D D B B G D D D D B D G B Caustic potash solution, 50% +60 D D C B B C D D C B C C B C D C Caustic soda Cellosolve +20 D G C B B B D D C B C C B C D B +20 G G G C C F G G G C G G B G G F Chlorine, liquid +20 G G D C C C C G D C D D B D G G Chlorine, gaseous moist +20 G G D C C C C G D C D D B D G D B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 188

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Chlorine, gaseous dry +20 G C D C C C C G D C D D B D G C Chloral hydrate, aqueous +60 G G D C C B C G D C D D B D G B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Chloramine, aqueous +20 F F B B B C G F B B B B B B F G Chloroethanol +60 G G D C C C D G D C D D B D G F Chlorobenzene +20 D F D D D C C D D D D D B D D C Chlorobromomethane +20 G G G C C C C C G C G G B G G C Chloroacetic acid +60 G D C B B C G G C B C D B D G D Chlorinated lime, aqueous +60 G D D B B B B G D B D D B D G B Chloromethyl +20 G C D D D B C G D D D D B D G B Chloroform +20 G D D D D B C G D D D D B D G B Chloric acid, aqueous +80 G G D C C B C G D C D D B D G B Chlorosulfonic acid +20 D G D D D F G D D D D D B D D F Chlorinated water, saturated +20 G G D B B B B G D C D D B D G B Chromic acid, aqueous +60 G G D B F B B G D F D D B D G B Chromic acid/sulfuric acid/ water, 50/15/35 % +40 G G D B F B B G D F D D B D G B Citric acid, aqueous +60 G G C B B B H F B B B B B B F B Clophen A types +100 F D D G G B B B D G D D B D B B Clophen T 64 +100 F D D G G B B F D G D D B D C B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 189 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Coconut fat +80 B B C D D B B B B D B D B D B B Coconut fatty alcohol +20 F G B C C B B F B C B C B C F B Coconut oil Coconut oil Cod liver oil +80 F F C G G B B F B G B D B D F B +60 B B C D D B B B B D B D B D B B +20 B B B C C B B B B C B C B C B B Coke oven gas +80 G G D D D B B F D D D D B D F B Copper(I) chloride, aqueous +20 B B C B B B B B B B B B B B B B Copper fluoride, aqueous +50 G G C B B B B F B B B B B B F B Copper nitrate, aqueous +60 G G C B B B B F B B B B B B F B Copper sulphate, aqueous +60 G G C B B B B F B B B B B B F B Cottonseed oil +20 F B C C C B B F B C B C B C F B Cresol, aqueous +45 G B D D D B B G D D D D B D G B Crotonaldehyde +20 G F G B B C D G G B G C B C G D Crude oil +20 B B C C D B B B C D B D B D C B Cyanide, aqueous +40 G F C B B B B B B B B B B B B B Cyanide, aqueous +80 G D C B B B B B C B C D B D B B Cyclohexane Cyclohexanol +20 C B D G D B B C B D B D B D C B +20 G B D D D B G C B D B D B D G B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 190

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Cyclohexanone +20 G G D D D B G G D D D D B D G G Cyclohexylamine +20 G G D D D C D G D D D D B D G D Decahydronaphthalene (decalin) Decahydronaphthalene (decalin) +20 C G D D D C C G D D D D B D G C +60 C G D D D C C G D D D D B D G C Desmodur T +20 D C D D D C G G D D D D B D G F Desmophen 2000 +80 F G F F F F F F B F B F B B F F Detergents, synthetic +60 D F C B B B B F B B B B B B F B Dextrin, aqueous +60 G D B B B B B B B B B B B B B B Dextrose, aqueous +80 G G B B B B B B B B B D B B B B Diacetone alcohol +20 G F C B B B G F C B C B B B F F Dibenzyl ether +20 G G D C C B D G D C D D B D G F Dibutyl ether +20 G G D C C B D G D C D D B D G F Dibuthyl phthalate +20 G B D F F B B B D F D D B D B B Dibuthylphtalat +60 G F D F F B C B D F D D B D B B Dibuthyl sebacate +60 G F D D D C G C D D D D B D C C Dichlorobenzene +20 G G D D D B B C D D D D B D G B Dichlorobutylene +20 G G D D D B C G D D D D B D G B Dichloroacetic acid +60 G D D B B C D G D B D D B D G F B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 191 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Dichloroethane +20 D D D G D C C F D D D D B D D C Dichloroethylene +20 G G D G G C C G D G D D B D G C Dichloromethane +20 D D D D D B B G D D D D B D D B Diesel fuel +60 C C C D D B B B B D B D B D C B Diethylamine +20 G G D B B C D G C B C D B D G D Diethylene glycol +20 G G B B B B B B B B B B B B B B Diethyl ether +20 G G D D D B D G D D D D B D G B Diethylsebacate +20 G G D C C C C G D C D D B D G C Diglycolic acid, aqueous +60 G G C B B B B F C B C B B B F B Dihexyl phthalate +60 G G D D G C D G D G D D B D G C Diisobutylketone +60 G G D F B C D G D B D C B D G F Dimethylamine +20 G G D B B C D G D B D D B D G D Dimethyl ether +20 G G D B B C D G D B D C B D G F Dimethylformamide +60 F D D C C C D F D C D C B D D F Dinonyl phthalate +30 G G D D G C D G D G D D B D G G Dioctyl phthalate +60 D G D D G B C G D G D D B D G B Dioctyl sebacate +60 G G D G G C D G D G D D B D G C Dioxane +60 G G D C C F D G D C D C B C G F B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 192

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12. Chemical resistance MEDIUM Dipents Diphenyl °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X +20 F F D D D B B F C D C D B D F B +20 G F D D D B B G D D D D B D G B Diphenyl oxide +100 G G G G G F G G G G G G B G G F Engine oils +100 B C C D D B B B B D B D B D C B Epichlorohydrin +20 G G G G C F D G G G G G B G G D Essential oils +20 G G D D D B C G D D D D B D G B Ethan +20 B B C D D B B B B D B D B D C B Ethanol (spirit) +20 G C C B B B H B C B C B B B C B Ethanol (spirit) +80 G D D B B B H F D B D B B B F B Ethanol (spirit) with acetic acid (fermentation mixture) (ethanol (spirit) with acetic acid fermentation mixture) +60 G G D B B B H G D B D B B B G B +20 G G C B B B H G D B D B B B G B Ethyl acetate +60 G D D D D C D G D D D D B D G D Ethyl acrylate +20 D G G G F C D D D C D G B G D D Ethylbenzene +20 D F D D D B C C D D D D B D D C Ethyl chloride +20 D C C F C B C G C C C C B C D C Ethylene chloride +20 D C C F C B C G C C C C B C D C B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 193 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Ethylenediamine +60 D D D F B C D G D B D C B C D D Ethylene glycol +100 G D C F B B B F B B B D B B C B Ethylene trichloride +20 G G G G G C F G G G G G B G G F Ethyl ether +20 D D D D C B D D D C D C B D D C Exhaust gases containing hydrogen fluoride, traces Exhaust gases containing carbon dioxide Exhaust gases containing carbon oxide +60 F G B B B B B F B B B B B B F B +60 B F B B B B B B B B B B B B B B +60 B B B B B B B B B B B B B B B B Exhaust gases, nitrous, traces +60 D G B B B B B C F C F D B F D B Exhaust gases, nitrous, traces +80 D G B B B B B C F C F D B F D B Exhaust gases containing hydrochloric acid Exhaust gases containing sulphur dioxide Exhaust gases containing sulphuric acid Exhaust gases containing sulphur +60 G G B B B B B F C B C B B B F B +60 G G B B B B B F C B C C B C F B +60 G G C B B B B F C B C C B C F B +80 G G C B B B B F D B D C B C F B FAM test fuels DIN 51604-A +20 G B D D D B B B C D C D B D D B FAM test fuels DIN 51604-C +20 D D D D D B H C D D D D B D D B Fatty alcohol +20 B G B C C B B F B C B C B C B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 194

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Fats, mineral, animal or vegetable +80 B B C C D B B B B D B D B D B B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Fatty acids +100 G G C C G B B G C G C G B G G B Fertilizer salt, aqueous +60 G G C B B B B B B B B B B B B B Fish oil +20 B F B C C B B B B C B C B C B B Fluorine, dry +60 G G G G G F G G D G D D B G G G Fluorobenzene +20 D G D D D B C D D D D D B D D B Fluorocarbon oils +100 F F F F F F F F F F F F B F B F Fluorosilicic acid +100 G G F F F F F F F F F D B F F F Formaldehyde, aqueous +60 D G C B B C G F C B C B B B F F Formamide +60 G G D B B B C G D B D B B F G F Formic acid, aqueous +60 G D D C C B G G D C D C B C G G Fruit juices +100 G D C B B B B F C B C D B B B B Furan Furfurol +20 G D G G G C D G G G G G B G G F +20 G D G G G C G G D G D G B G G F Furfuryl alcohol +20 G D G G G C G G G G G G B G G F Gasohol +20 D D D D D B H C D D D D B D D B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 195 X E D N I

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Materials and Process Engineering MEDIUM Gas oil Gas water Gasoline Gasoline-benzene-ethanol, 50/30/20% Gasoline-benzene mixture, 50/50% Gasoline-benzene mixture, 60/40% Gasoline-benzene mixture, 70/30% Gasoline-benzene mixture, 80/20% °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X +80 B B C D D B B B B D B D B D C B +40 D G D D D B B D B D B D B D D B +60 D D C D D B B B C D C D B D D B +20 D D D D D B H C D D D D B D D B +20 D C D D D B B C D D D D B D D B +20 D C D D D B B C D D D D B D D B +20 D B D D D B B B D D D D B D D B +20 D B D D D B B B D D D D B D D B Gelatine, aqueous +40 C G C B B B B B B B B B B B B B Glacial acetic acid +60 G D D C C C D G D C D D B D G G Glauber's salt, aqueous +20 C G C B B B B F B B B B B B F B Glucose, aqueous +80 G G C B B B B B B B B C B B B B Glue +20 B B B B B B B B B B B B B B B B Glycocoll, aqueous, 10% +40 F G B C B B B F C B C C B C F B Glycol, aqueous +100 G D C B B B C F B B B C B B C B Glycolic acid, aqueous, 37% +20 G G C B B B B B B B B B B B B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 196

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Glycerine, aqueous +100 G G C B B B B B B B B C B B B B Glycerol chlorohydrin +60 G G D C C C G G D C D C B C G F Heating oil (petroleum-based) +60 B B C D D B B B B D B D B D C B Henkel P-3 solution +100 G G C B B B G F B B B C B B F F Heptane +60 B B C D D B B B B D B D B D D B Hexachlorobutadiene +20 G G G G G B B G D G D D B D G B Hexachlorocyclohexane +20 G C G G G B B F G G G D B D G B Hexaldehyde +20 G G D G G C G G D G D D B D G F Hexane Hexanetriol Hexene +60 B B C D D B B B B D B D B D D B +20 G G C B B B B B B B B F B F B B +20 B B C C D B B B C D C D B D F B Hydraulic fluids, hydraulic oils DIN 51524 Hydraulic fluids, phosphoric acid esters HFD Hydraulic fluids, polyglycol-water HFC Hydraulic fluids, Oil-in-water emulsions HFA Hydraulic fluids, water-oil emulsions HFB +80 B B C D D B B B B D B D B D C B +80 D D D D H B H D D H D D B D D B +60 G G C B B B B B B B B B B B B G +55 G G C D D B H F B D B D B D F G +60 G G C D D B H F H D H D B D F G B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 197 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Hydrazine hydrate +20 G C C B B C G C C B C D B C G F Hydrobromic acid, aqueous +60 G D C B B F G G C B C F B F G G Hydrochloric acid, conc. +20 G G D B B B B G D B D C B C G B Hydrochloric acid, conc. +80 G G D B B B C G D B D D B D G B Hydrochloric acid, diluted +20 G D C B B B B G C B B B B B G B Hydrofluoric acid, conc. +20 G G G C C C G G G C G G B C G F Hydrofluosilicic acid, aqueous +60 G G C B B B B G B B B B B B G B Hydrogen +20 B G B B B B B B B B B B B B B B Hydrogen chloride gas +60 G G D B B B B G D B D C B C G B Hydrogen phosphide +20 G G C B B C C F D B D B B F F C Hydrogen peroxide, aqueous +20 G G D B B B B C D B D D B D C B Hydrogen sulphide, dry +60 G F C B B B B F C B C C B C F B Hydrogen sulphide, aqueous +60 G G C B B B B G C B C C B B G B Hydroquinone, aqueous +20 C G C B B B B F B B B C B C F B Hydrosulfite, aqueous +40 G G C B B C G F C B C B B B F F Hydroxylamine sulfate, aqueous +35 G G C B B C G B B B B B B B B F B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 198

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Illuminating gas, petrol-free +20 B B C D D B B B B D B D B D B B Ink Iodoform +20 B B B B B B C B C B B B B B B B +20 G G G G B B B G G B G G B G G B Iron(III) chloride, aqueous +40 G F B B B B B F B B B B B B F B Isobutyl alcohol +20 D D B B B B B C C B C B B B B B Isooctane Isophorone Isopropanol +20 B C C D D B B B B D B D B D C B +20 F C F F B C F F F B F F B F F F +60 D G C B B B H B C B C B B B B B Isopropyl acetate +80 D G D C C C D D D C D D B D D D Isopropyl ether +60 D D D G G B D D D G D G B D D B Isopropyl chloride +20 D D D D D B B C D D D D B D D B Kerosene Kerosene +20 B B D D D B B B C D B D B D C B +60 F F B D D B B F B D B D B D F B Kerosene emulsions +40 B B B D D B B B B D B D B D B B Kerosene oil Lactam +60 B B B D D B B B B D B D B D B B +80 G G D D D C D G D D D D B D G F Lactic acid, aqueous 10% +40 G B B B B B B F B B B B B B F B Lanolin (wool grease) +60 B B C C D B B B B D B C B C B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 199 X E D N I

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Materials and Process Engineering MEDIUM Lauryl alcohol Lavender oil °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X +20 F F B C C B B F B C B C B C F B +20 C F D G G B B C C G C G B G G B Lead acetate, aqueous +60 G D C B B B B F C B B B B B F B Lead acetate, aqueous +100 G D C B B B D F C B B D B B F F Lead nitrate, aqueous +20 F D C B B B B F B B B B B B F B Lemon juice, undiluted +20 G F C F F B H F B F B B B B B B Linseed oil Linoleic acid Liqueurs +60 F C B C C B B F B C B C B C B B +20 G F G G G B C F C G C G B G C B +20 B B B B B B B B B B B B B B B B Lithium bromide, aqueous +20 G B C B B B B B B B B B B B B B Lithium chloride, aqueous +20 G B C B B B B B B B B B B B B B Machine oils, mineral +80 B B C D D B B B B D B D B D C B Magnesium chloride, aqueous Magnesium sulphate, aqueous +100 D G C B B B B F B B B G B B F B +100 D G C B B B B F B B B G B B F B Maize germ oil +60 F F C G D B B F B D B D B D F B Maleic acid, aqueous +100 G G C B B B B F B B B D B D F B Maleic anhydride +60 G G G G G B B F G G G G B G G B Margarine +80 B B C D D B B B B D B D B D B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 200

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12. Chemical resistance MEDIUM Menthol Mercury °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X +60 G G D D D B C G D D D D B D G B +60 B B B B B B B B B B B B B B B B Mercury salts, aqueous +60 G G C B B B B B B B B B B B B B Mesityl oxide +20 G F G G C F F F F C F G B G G F Methane Methanol +20 B F B C C B B B B C B C B C B B +60 G G C B B B H B C B C B B B C B Methoxybutanol +60 G F C C C B B F B C B D B D F B Methyl acrylate +20 D D D D D C D D D D D D B D D G Methylamine, aqueous +20 G G G B B C D G D B D C B C G D Methyl bromide +20 D D D D D B B F D D D D B D D B Methylene chloride +20 D D D D D B B G D D D D B D D B Methyl ethyl ketone +20 D D D C C B D D D C D D B D D F Methyl isobutyl ketone +20 D D D D C C D D D C D D B D D F Methyl methacrylate +20 D D D D D C D D D D D D B D D F Methyl-tert-Butylether +20 D D D D D B D D D D D D B D D D Milk Milk of lime Mine gas +20 G B B C C B B B B C B C B C B B +80 G G C F F B B G D F D D B C G B +20 B F B C C B B B B C B C B C B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 201 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Mineral oil +100 B C D D D B B B B D B D B D C B Mineral water +60 G F C B B B B B B B B B B B B B Molasses +100 G G C C C B B F B C B D B D F B Monobromobenzene +20 D D D D D B C D D D D D B D D F Monochloroacetic acid ethyl ester Monochloroacetic acid methyl ester +60 D D D C C B C D D C D D B D D B +60 D D D D B B C D D B D D B D D B Morpholine +60 G G D C C F G F D C D D B D F F Myristyl alcohol +20 B F B B B B B F B B B B B B F B n-propanol Naftolen ZD Naphtha Naphthalene Naphtoic acid Natural gas +60 G D C B B B C B C B C B B B B B +20 F G D D D B B F C D C D B D G B +20 C D D G G B B C D G D G B G G B +60 G G D D D B B G D D D D B D G B +20 G G F G G B B B C G C G B G G B +20 B B B C C B B B B C B C B C B B Nickel acetate, aqueous +20 G D C B B C F F B B B B B B F F Nickel chloride, aqueous +20 G G C B B B B F B B B B B B F B Nickel sulphate, aqueous +60 G G C B B B B F B B B B B B F B Nitric acid, conc. +80 G D D B D F D G D D D D B D G F B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 202

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Nitric acid, fuming +60 G D D D D F D G D D D D B D G F Nitric acid, diluted +80 G G C B C B C G C C C D B C C B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Nitrobenzene +60 D D D D D C D D D D D D B D D F Nitrogen +20 B B B B B B B B B B B B B B B B Nitrogen tetraoxide +20 G G G G D F G G G D G G B G D F Nitroglycol, aqueous +20 G F C B B B B F D B D F B F F B Nitroglycerine +20 G G G B B B B G D B D C B C G B Nitromethane +20 D D G C C C D D D C D C B C D F Nitropropane Nitrous gases Nitrous oxide +20 D D D C C F D D D C D C B C D F +20 D D D B B B B D D B D D B D D B +20 B B B B B B B B B B B B B B B B o-nitrotoluene +60 D G D D D F D D D D D D B D D F Octylcresol Octane Octyl alcohol Oleum, 10% Oleyl alcohol Olive oil +20 D G D D D C C D G D G D B D D C +20 G F G G G B B C F G F G B G G B +20 G G B B B B B C C B C C B C C B +20 D D D C C B B D D C D D B D D B +20 B D B B B B B B B B B B B B B B +60 B F B C C B B B B C B C B C B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 203 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Oleic acid +60 B G C D D B B C B D B D B D C B Oxalic acid, aqueous +100 G G D B B B B G D B D D B C G B Ozone +20 C F C B B B B B C C D D B D B B Palmitic acid +60 F F C D D B B F C D C D B D F B Palm kernel fatty acid +60 F F B D D B B F B D B D B D F B Photo emulsions +20 G G B B B B B F B B B B B B F B Photo developer +40 G G C B B B B F C B C B B B F B Photo fixing baths +40 G G C B B B B F C B C B B B F B Pectin +20 B B B B B B B B B B B B B B B B Pentachlorodiphenyl +60 G G D D D F G G D D D D B D G F Pentane +20 F F C D D B B F B D B D B D F B Perchloroethylene +60 G G D D D B B G D D D D B D D B Perchloric acid +100 G G D B B B B G D B D D B D G B Peracetic acid, < 1% +40 D D D D B B B D D D D D B D D B Peracetic acid, < 10% +40 D D D D C B H D D D D D B D D B Petroleum ether +60 B B C D D B B B C D B D B D C B Petroleum +60 B B C D D B B B B D B D B D C B Phenol, aqueous, up to 90% +80 G G D D D B C G D D D D B D G B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 204

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Phenyl ethyl ether +20 D D D D D C D D D D D D B D D F Phenylbenzene +20 G G D D D B C G D D D D B D G B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Phenylhydrazine +60 G G D D D B C G C D C D B D G C Phenylhydrazine chlorohydrate, aqueous +80 G G D C B C C G C B C D B D G C Phosgene +20 G G G F F F F G G G G G B G G F Phosphorus oxychloride +20 G G G F F F F G D G D G B F G F Phosphoric acid, aqueous +60 G G C B B B B G D B D C B B G B Phosphorus trichloride +20 G G D B B C C G D B D B B F G C Phthalic acid, aqueous +60 G G C B B B B F B B B D B F F B Picric acid +20 G C B C C B B C C C C C B C G B Picric acid, aqueous +20 G G C B B B B B B B B B B B B B Pimple solution (leather pimple) +20 G G F C C C C G F C F G B G G C Pine needle oil +60 B B D D D B B B C D C D B D C B Pinene Piperidine Potash +20 G C C C G B B C C G C G B G G B +20 G G G G G F G G G G G G B G G F +40 G G C B B B B B B B B B B B B B Potassium acetate, aqueous +20 G C C B B B B F C B B B B B F B Potassium bisulfate, aqueous +40 G D C B B B B F B B B B B B F B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 205 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Potassium borate, aqueous +60 G D C B B B B F B B B B B B F B Potassium bromate, 10% +60 G D C B B B B F B B B B B B F B Potassium bromide, aqueous +60 G D C B B B B F B B B B B B F B Potassium carbonate, aqueous +40 G G C B B B B B B B B B B B B B Potassium chlorate, aqueous +60 G D C B B B B F D B D C B C F B Potassium chloride, aqueous +60 G D C B B B B F B B B B B B F B Potassium chromate, aqueous Potassium dichromate, aqueous 40% +20 G D C B B B B F C B C B B B F B +20 G G C B B B B F C B C D B C F B Potassium iodide, aqueous +60 G D C B B B B F B B B C B B F B Potassium nitrate, aqueous +60 G D C B B B B F B B B B B B F B Potassium perchlorate, aqueous Potassium permanganate, aqueous Potassium persulfate, aqueous Potassium sulphate, aqueous +80 G G C B B B B F D B D D B D F B +40 G G C B B B B G D B D D B C G B +60 G G D B B B B G D B D D B C G B +60 G G C B B B B F B B B B B B F B Propane, liquid/gaseous +20 B B B G G B B B B G B D B D B B Propargyl alcohol, aqueous +60 F G B B B B B F B B B C B F F B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 206

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Propionic acid, aqueous +60 G G C F F B B G B F B G B F G B Propylene glycol +60 G G C B B B B F B B B B B B F B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Propylene oxide +20 G G G G G C G G D G D G B G G G Prussic acid +20 G G C B F B F F F B F F B F B B Pyridine Pyrrole +20 D D D G G F D D D G D D B D D F +20 G G G G D F F C G D G D B D C F Rapeseed oil +20 C C C C C B B B C C C G B G G B Refrigerant according to DIN 8962 R 134a Refrigerant according to DIN 8962 R 134a +20 G C B B B G D F D B D B B B G G +20 G G B G B D D F C G C G B G G G Roasting gases, dry +60 G G C B B B B B D B D B B B B B Sagrotan Salicylic acid Salt water Seawater +20 G D C B B B B B C B C B B B B B +20 G B B B B B B G B B B B B B G B +20 G G B B B B B B B B B B B B G B +20 G C C B B B B B B B B B B B B B Silicic acid, aqueous +60 G G C B B B B G B B B B B B G B Silicone grease +20 B B B B B B B B B B B C B B D B Silicone oil +20 B B B B B B B B B B B C B B D B Silver nitrate, aqueous +100 G G C B B B B F C B C G B C F B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 207 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Silver salts, aqueous +60 G G C B B B B B C B C C B C B B Skydrol +20 D D D G C C D D D F D D B D D D Soap solution, aqueous +20 G B C B B B B F B B B B B B F B Soda, aqueous +60 G G C B B B B B B B B B B B B B Sodium benzoate, aqueous +40 G F C B B B B F B B B B B B F B Sodium bicarbonate +60 G G C B B B B F B B B B B B F B Sodium bicarbonate, aqueous +60 G G C B B B B F B B B B B B F B Sodium bisulfite, aqueous +100 G G C B B B B F B B B B B B F B Sodium chlorate +20 G G D B B B B F D B D D B D F B Sodium chloride +100 G G C B B B B F B B B G B B F B Sodium hypochlorite, aqueous +20 G G C B B B B F C B C D B D F B Sodium nitrate, aqueous +60 G G C B B B B F B B B B B B F B Sodium nitrite +60 G G C B B B B F C B C B B B F B Sodium phosphate, aqueous +60 G G C B B B B F B B B B B B F B Sodium silicate, aqueous +60 G G C B B B B F B B B B B B F B Sodium sulphate, aqueous +60 G G C B B B B F B B B B B B F B Sodium sulfide Sodium sulfide +40 G G C B B B B F B B B B B B F B +100 G G C B B B B F C C C D B C F B Sodium thiosulfate +60 F G B B B B B F D B D B B B F B Spermaceti +20 F F C D D B B F B D B D B G F B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 208

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Spruce needle oil +20 G F D G G B B F C D C D B D G B Spindle oil +60 B B C D D B B B B D B D B D B B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Starch, aqueous +60 G G B B B B B B B B B B B B B B Starch syrup Stearic acid Steam +60 G G B B B B B F B B B B B B F B +60 B B C B B B B B B B B D B B B B +130 G D D C B D H D D B D D B D D B Stoddard graduate +20 B B D D G B B B B G B G B G G B Styrene +20 G G D D D F C G D D D D B D D F Succinic acid, aqueous +60 G D C B B B B F B B B B B B F B Sugar syrup Sulphur +60 G G G B B B B F B B B B B F F B +60 G F G B B B B F G B G G B G F B Sulphur chloride +20 G G D C G B B B D G D G B G G B Sulphur dioxide, liquid +60 G G D B B B B G D B D D B G G B Sulphur dioxide, dry +80 G G D B B B B F D B D D B C F B Sulphur dioxide, aqueous +60 G G D B B B B G D B D D B C G B Sulphur hexafluoride +20 F F B B B B B B B B B F B B B B Sulphuric acid, conc. +50 G D D B B B C G D B D D B C D B Sulphuric acid, diluted +20 G G D B B B B G C B C C B C G B Sulfuryl chloride +20 G G D B C B B G D C D C B C G B Tallow +60 F G C D D B B F B D B D B D F B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 209 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Tannic acid +60 C G C B B B B B B B B B B B B B Tanning extracts +20 C G C B B B B B B B B B B B B B Tannin Tar Tar oil +40 G B B B B B B F C B C B B B F B +20 G G D D D B F G D D D D B D G B +20 G G D D D B F G D D D D B D G B Tartaric acid, aqueous +60 G G C B B B B B B B B B B B B B Tetrachloroethane +60 G G D D D B C G D D D D B D G B Tetrachloroethylene +60 G G D D D B C G D D D D B D G B Tetraethyl lead +20 G G D D G B B C C G C G B G G B Tetrahydrofuran +20 G G D D D C D G D D D D B D G F Tetrahydronaphthalene (Tetralin) +20 G G D D D B B F D D D D B D G B Thionyl chloride +20 G G D B B B B G D B D C B C G B Thiophene +60 G G D D D F D G D D D D B D G F Tin(II) chloride, aqueous +80 G G C B B B B F B B B B B B F B Tincture of iodine +20 G D C B B B B C B B B B B B C B Titanium tetrachloride +20 C B C B B B C C B B B B B B C B Toluene +20 D D D D D B C D D D D D B D D B Transformer oil +60 B B D D D B B B C D B D B D C B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 210

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12. Chemical resistance MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Transmission fluid type A +20 B B C C G B B B B G B G B G C B Triacetin +20 G G C C B F G G C B C C B D G F Triethanolamine +20 G G C C C C G G D C D D B F G G Triethylaluminum +20 G G G G G C C G G G G G B G G C Triethylborane +20 G G G G G B B G G G G G B G G B Tri-n-butyl phosphate +60 D D D D F B D D D D D D B D D F Tributoxyethyl phosphate +20 G G D D D B C G D D D D B D G F Trichloroacetic acid, aqueous +60 G G D C C B D G C C C C B C G F Trichloroethylene +20 G D D D D B C G D D D D B D D F Trichloroethyl phosphate +20 G G D G G C D G D G D G B G G F Triglycol +20 G F B B B B B F B B B B B B F B Tricresyl phosphate +60 G C D D C F C F D C D D B D G F Trimethylolpropane, aqueous +100 G G C C C B B F D C D C B F F B Trisodium phosphate +20 G F C B B B B B B B B B B B B B Trinitrotoluene +20 G G C C G B C C G G G G B G G B Trioctyl phosphate +60 G G D C C B C F D C D D B G G B Turpentine +60 F D D D D B B G C D C D B D G B Turpentine oil +20 F G D D D B B G C D C D B D G B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 211 X E D N I

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Materials and Process Engineering MEDIUM °C 1) M C A U A R C M S C M D P E M K F F M K F Q M V F R B N H R B N R N E F T P R B S R I I Q M V P X Urea, aqueous +60 G G C B B B B F B B B B B B F B Vaseline Vaseline oil +60 B F B C D B B B B D B D B D C B +60 B F B C D B B B B D B D B D C B Vinyl acetate +20 G G G G G C G G G G G G B G G G Vinyl chloride, liquid +20 G G G G G C G G G G G G B G G G Wax alcohol +60 F F C D D B B F C D B D B G F B Water Water vapor White spirit White oil Whisky Wine +100 D D C B B C C F B B B C B B C B +130 G D D C B D H D D B D D B D D B +60 B F C D D B B F C D B D B D F B +20 B F C C G B B B B G B G B G B B +20 G B B B B B B B B B B B B B B B +20 F B B B B B B B B B B B B B B B Wool grease +50 B B B B B B B B B B B C B B B B Xylamon Xylene +20 D C D D D B C G D D D D B D G B +20 D D D D D B C D D D D D B D D B Yeast, aqueous +20 G F B B B B B B B B B B B B B B Zeolite Zinc acetate +20 B B B B B B B B B B B B B B B B +20 B B C C B B B B C B C B B D B B B = Low or no attack C = Weak to moderate attack D = Severe attack to complete destruction F = No data available, probably suitable, check before use. G = No data available, probably not suitable. H = Special mixture structure required. 1) Test temperature in °C The above information is based on the experience of decades of research in the development and manufacture of seals at the Freudenberg Group. Nevertheless, chemical resistance is only one aspect of the overall operating conditions and there is a possibility that the properties of seals may be noticeably restricted due to unknown factors during practical use. This informa- tion can therefore only represent general, non-binding guide values. We therefore recommend discussing specific applications with our consulting service and always testing them in advance. You can find the latest information on resistance online in our Chemical Resistance Guide. 212

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13. Summary of the standards mentioned 13. SUMMARY OF THE STANDARDS MENTIONED I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A NORM DIN 3601 DIN 3760 DIN 3761 DIN 7168 DIN 7715 DIN 7716 DIN 9088 DIN 16901 DIN 24320 DIN 51524 DIN 51604 DIN 53504 DIN 53508 O-rings - Fluid technology R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Radial shaft seals Radial shaft seals for motor vehicles General tolerances (free size tolerances) Rubber parts – permissible dimensional tolerances Products made of rubber; Guidelines for storage, maintenance and cleaning Aerospace guidelines for the permissible storage times of products made of elastomers Plastic molded parts; tolerances and acceptance conditions for length dimensions Pressure fluids of the HFAE and HFAS category, properties and requirements Pressure fluids – Hydraulic oils – HL, HLP, HVLP FAM test fuel for polymer materials; composition and requirements Testing of elastomers – tensile test Testing of elastomers – Artificial ageing of soft rubber R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 213 X E D N I

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Materials and Process Engineering NORM DIN 53512 DIN 53513 DIN 53533 DIN 53538 DIN 53545 DIN ISO 34-1 DIN ISO 48 DIN ISO 812 DIN ISO 815 Testing of elastomers; determination of rebound resilience Testing of rubber and elastomers; determination of the viscoelastic properties of rubber under forced off-resonance vibrations Testing of elastomers; testing of heat generation and crushing resistance in the fatigue test Testing of elastomers; standard reference elastomers Determination of the behavior of mineral oil products compared to nitrile rubber vulcanizates Testing of elastomers; determination of behavior at low temperatures (low-temperature behavior); terms, symbols and test methods Testing of elastomers; tear propagation test with the strip specimen Elastomers and thermoplastic elastomers; determination of hardness Testing of elastomers; determination of the cold brittleness temperature under impact stress Testing of elastomers; determination of compression set at ambient, elevated or low temperatures DIN ISO 1431-1 Determination of resistance to cracking under the influence of ozone Testing of caoutchouc and rubber; DIN ISO 1629 Rubber and Latices; Classification Abbreviations DIN ISO 1817 DIN ISO 4649 214 Testing of rubber and caoutchouc; Determination of the effect of liquids Testing of rubber and elastomers; wear test; determination of abrasion

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13. Summary of the standards mentioned Testing of rubber and caoutchouc; hardness testing according to Shore A and D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Testing of plastics and elastomers; determination of density NORM DIN ISO 7619-1 DIN EN ISO 1183 DIN EN ISO 6721 Testing of polymer materials; torsional vibration test VDMA 24317 ASTM D 395 ASTM D 471 ASTM D 746 Fluid technology; flame-retardant hydraulic fluids; minimum technical requirements Testing of rubber; determination of compression set Testing of rubber; determination of the behavior against liquids Determination of the embrittlement temperature of plastics and elastomers under impact stress ASTM D 945 Determination of the behavior under compressive deformation or shear stress (mechanical vibration meter) Testing of rubber; ASTM D 1418 ASTM D 1600 Rubber and rubber-latex; classification and designations Standard terminology for abbreviated terms in connection with plastics ASTM D 2000 Classification of rubber products for the automotive industry R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 215 X E D N I

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Materials and Process Engineering 14. EXCURSUS: COMMON TERMINOLOGY IN THE RUBBER INDUSTRY Agglomerates Agglomerates are powdery substances that have been combined into a solid compound using technical processes. This connection is based on purely phys- ical forces and can be easily dissolved again depending on the process used. Agglomeration is preferably used to avoid dust emissions or to make powder materials easier to handle. In everyday life, agglomerates are used in instant coffee, for example. Aggregate state Aggregate states are the phases that matter can assume. These are solid, liquid or gaseous. A fourth aggregate state de- scribed by physics is plasma – an ionized gas. The transitions are shown in → Fig. 89. Amorphous This term describes the arrangement of atoms in a body. In contrast to crystals, amorphous materials do not have an or- dered structure. Elastomers belong to the amorphous materials, as their polymer chains are disordered in the matrix. Aromatics Aromatics are special ring-shaped struc- tures that are unsaturated, i.e. have double bonds. These double bonds are conjugat- ed, i.e. there is a single bond between each double bond. This gives aromatics their typical chemical properties. Aromatics exist as mono- and poly-rings. Brownian molecular motion This type of movement of molecules is named after the Scottish botanist Robert Brown, who observed the jerky and random movement of tiny particles in liquids in 1827. Molecules always have their own motion as soon as their temperature is above the absolute zero point of 0 Kelvin (–273.15 °C). This movement increases the warmer an object is and ultimately represents the definition of temperature. Brownian motion is based on collisions that molecules can exert due to their own motion. The higher the temperature, the more pronounced the Brownian motion, as more energy can be transferred by the molecules. i o n < R e c o m b i n a t i o n > I o n i z a t < Vaporize Condensing > y i n g o li d i f M e l t i n g > < S PLASMA LIQUIDITY GAS > n o i t a m i l b u S n o i t a m i l b u s e R < FIXED BODY Fig. 89 Overview of the aggregate states and their transitions 216

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14. Excursus: Common terminology in the rubber industry Dispersing Dispersing is the homogeneous mixing of at least two substances that are soluble in each other. The term "emulsion paint" is commonly used in everyday life. The pigments in these paints are so evenly distributed that they give the impression of a homo- geneous mixture. The degree of dispersion therefore describes how well the compo- nents are distributed in the mixture. Entropy elasticity This term is a combination of a physical quantity and a physical property of a ma- terial. These are briefly explained below before the entropy elasticity is discussed in more detail. Entropy In simple terms, entropy is the disorder of a system. Disordered states have a much lower energy level than ordered states. In nature, everything automatically strives towards the lowest possible energy level. Any deviation from this principle is associated with the supply of energy. If you mix apple juice in water, for ex- ample, you can see streaks of pure fruit juice for a short time. These streaks represent a higher order, as the water and juice are arranged next to each other. Without external influence, the juice will now be evenly distributed in the water, which repre- sents a more disordered state as the juice and water are mixed together – a state of the lowest energy level. Elasticity Elasticity describes the ability of a ma- terial to return to its original shape af- ter deformation. For example, a spring will return to its original shape after moderate deformation. Elastomers consist of long, partly branched molec- ular chains. Due to their structure, the individual links can rotate against each other. This rotatability is disordered, which leads to a randomly aligned polymer ball. This means that the molecular chains are intertwined and twisted. A certain entropy or disorder can be as- signed to this state. If the material is now shaped, the molecular chains slide against each other. The entanglements or twists are dissolved – the polymer chains assume an ordered state with a higher energy level. If the force used to deform the material is removed, the ma- terial will return to a more disordered state of entanglement due to entropy elasticity and possible low energy levels. The new outer shape will be the same as the initial shape due to the elastic com- ponent. On a molecular level, however, a new arrangement occurs until the lowest energy level is reached due to the random rotatability of the chain elements. Glass transition temperature As already explained with regard to en- tropy elasticity, elastomers consist of ran- domly interlaced polymer chains, which are created by the possibility of rotational movement of the individual chain links. This flexibility increases the higher the temperature. Externally, an elastomer thus becomes easier to stretch and less rigid. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 217 X E D N I

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Materials and Process Engineering However, the exact opposite happens as the temperature falls and the chain links find it increasingly difficult to move due to the lack of thermal energy. At the glass transition temperature (Tg), the point is reached at which movement is no longer possible. Below this temperature, the ma- terial solidifies and assumes a brittle, glass-like state. This process is reversible. The glass transition temperature is signif- icantly influenced by the degree of cross-linking. Higher cross-linking always leads to a restriction of movement of the polymer chains, which is why the materi- al becomes correspondingly harder → Tg is increased. Hooke's law This law describes a special form of elas- tic behavior. Hooke's law states that the deformation of a material is proportion- al to the force acting on it. This is particu- larly the case with metals when they are subjected to moderate deformation. This is also referred to as energy elasticity. Isotropy In physics, isotropy describes the inde- pendence of a property from the direction of observation. In everyday life, we are familiar with the effect of a light bulb. Its light rays are not directional and can therefore be emitted in all three spatial directions. In the field of elastomers, isotropy de- scribes a directional independence when it comes to physical quantities. Rubber materials generally behave isotropically. For example, the hardness of an elasto- mer is the same in every direction due to its isotropic properties. However, slight anisotropic tendencies can be detected in the tensile strength test, which are caused by the rolling processes. However, the effects on the functionality are very small. Kerosenes Kerosenes are long-chain, saturated al- kanes. In everyday life, kerosenes are known as candle wax, for example. They can be liquid at lower chain lengths and solid at higher chain lengths. Naphthenes Naphthenes are cyclic (ring-shaped) compounds that consist of saturated hydrocarbons. They are therefore alkanes that are present in ring structures. The structures range from simple ring struc- tures (monocycles) to interconnected rings (polycyclic alkanes). These can have two nodes, bridge connections or simple nodes, or occur as so-called spiro com- pounds. Permeability The term "permeability" refers to the gas permeability of a material. It is a charac- teristic value for how well a material allows gases to pass through it or how well it retains them. Basically, all polymer materials are gas-permeable. Although the value can be reduced by various ad- ditives, gas permeability can never be completely prevented. In everyday life, we encounter permeabil- ity in plastic sparkling water bottles. These are filled with a higher gas pressure, as the carbonic acid degrades during longer storage due to the gas permeabil- ity. With glass bottles, which are gener- ally impermeable to gas, these high pres- sures are not necessary as the carbonic acid cannot degrade . 218

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14. Excursus: Common terminology in the rubber industry Plasticizing “Plasticizing” refers to the improvement of flowability. Depending on the sub- stance group, this can be achieved by increasing the temperature. Increasing the temperature usually results in a reduction in viscosity – a measure of flowability. In some cases, a flowability is required that cannot be achieved by increasing the temperature. Plasticizers or similar sub- stances are used here, to achieve the effect of plastification, for example. Radial force and axial force These two terms describe the direction of forces in relation to a shaft. The term "radial force" refers to the force that runs perpendicular to the shaft, whereas the axial force runs parallel to the shaft. You can memorize the difference by im- agining the forces as arrows. If we look at the radius of the shaft, we can measure it from the center to the edge of the shaft. Radial forces also act in exactly this direction. If we measure the length of the shaft or axle, we would measure it along the axis. The axial forces act accordingly in this di- rection. Reversible and irreversible effects An effect is reversible if it can be reversed. In sealing technology, this is particularly attractive in the case of expansions or compressions of seals, as these should counter the deformation in a reversible manner. Radial force Axial force Fig. 90 Radial and axial force In everyday life, we know reversible effects from springs that are pulled apart and then return to their original shape as soon as they are released. The bending of a metal sheet is a permanent deforma- tion and is therefore irreversible. The shattering of glass is also irreversible, as it does not reassemble itself. RGT rule (derived from Arrhenius equation) The reaction rate-temperature rule – also known as Van't Hoff's law – states that the reaction rate doubles or triples with a temperature difference of 10 Kelvin. This rule was derived from the Arrenius equation and represents a simplification. Since the vulcanization reaction does not depend on this rule, it is important to en- sure good process monitoring. Irreversible effects, on the other hand, are external forces or influences that cannot be reversed. However, it is also advisable to take this rule into account in the daily use of seals, as a seal can be exposed to chemical I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 219 X E D N I

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Materials and Process Engineering attacks, which usually occur more quickly at high temperatures. In everyday life, the validity of the RTG rule can be seen, in cooking processes, for example: The higher the temperature, the faster the cooking process. Rubber The term rubber is not specific. On the one hand, it stands for the base polymer, which is not cross-linked and therefore has no elastic properties. On the other hand, it refers to the vulcanized rubber that we are familiar with in everyday life. In the private sector, however, it is main- ly the elastic, cross-linked material that is referred to, as non-cross-linked rubber of- fers no possibility of end use. Saturated and unsaturated compounds Molecules without double bonds are referred to as "saturated compounds." The opposite are unsaturated compounds, which accordingly have double bonds in their structure. In everyday life, we are familiar with this type of compound in oils and fats. On the one hand, there are monounsaturated or even polyunsaturated oils (olive oil). On the other hand, there is the saturated variant (deep-frying fat). While our body can V R M Fig. 91 Diagram of the stick-slip effect 220 carry out reactions on unsaturated com- pounds, this is not the case with saturated molecules. A similar situation exists in the sealing in- dustry when the task is to provide seals that have to withstand oxygen or ozone or other oxidative chemicals. Here, as can be assumed, the less reactive, saturated compounds are more suitable. Stick-slip effect When bodies switch quickly between sticking and sliding during movements, the so-called stick-slip effect comes into play. This rapid change creates an oscilla- tion that is usually accompanied by bright sounds. The mechanism is based on a cy- clical sequence of adhesion, build-up of tension, release of tension and slipping, followed by adhesion again. An equivalent diagram makes this effect clearer. A hand crank can be seen, which is connected to a spring via a threaded spindle. The spring in turn is connected to a mass. If the crank is now turned to move the mass, tension is built up in the spring, while the weight does not move at first. This is due to the fact that the static friction is greater than the tensile stress at this moment. If the tension ex- ceeds the static friction, the mass begins to slide – the tension in the spring is re- leased. The mass comes to a stop because the static friction again exceeds the tension in the spring. This process now repeats itself. In everyday life, the stick-slip effect is known in the form of squealing tires dur- ing braking, the sound produced by string instruments or a glass harp, and creaking doors.

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14. Excursus: Common terminology in the rubber industry Viscoelasticity Viscoelastic behavior is a combination of two mechanical behaviors. The term in- cludes both elastic and viscous or plastic behavior. An elastic material is one which, after a forced deformation, returns to its initial state. A spring, for example, can be compressed or extended to a certain degree without being permanently de- formed. This happens without a time delay. In order to maintain this defor- mation, this force must be applied at all times. A material that yields to a deformation without restriction and retains the de- formed state behaves "plastically" or "vis- cously." It is not able to return to its orig- inal shape. Liquids respond irreversibly to deformation, i.e. they exhibit viscous behavior. In addition, this deformation occurs with a time delay. Viscoelastic behavior is the combination of both properties. It describes a body that strives to return to its original state after deformation, but yields to a certain extent to the deformation. Rubber materials are said to behave viscoelastically, although the elastic com- ponent is predominant. In practice, this means that elastomers deform to a certain extent after a force is applied (elastic component). However, this force decreases with a time delay and the elastomer structure adapts to the deformation (viscous part). How strong- ly or weakly the elastomer yields to this deformation can therefore be seen as the "quality." The simplified model of this behavior is shown in the following diagram. The elas- tic component, indicated by a spring, is shown on the left and the viscous com- ponent, indicated by a damper, is shown on the right. In practice, there are corre- spondingly more complex models with different combinations of these two com- ponents. K Fig. 92 Kelvin body as a model of visco- elastic behavior I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 221 X E D N I

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Materials and Process Engineering 222

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S E A L S F O R R O T A R Y A P P L I C A T I O N S 2 2 3 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING INTRODUCTION & SERVICES

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Seals for Rotary Applications TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. PRODUCT GROUPS 2.1 Simmerring® 2.2 2.3 2.4 Radiamatic® shaft seals Simmerring® cassette seals Simmerring® combi seals 3. SEALING MECHANISM USING THE EXAMPLE OF THE SIMMERRING® 3.1 3.2 3.3 3.4 3.5 Influencing parameters Dynamic sealing function Sealing lips with helix (special design) Lubrication and friction Static tightness and fit in the bore 4. MEDIA TO BE SEALED Fluid and material selection Interactions between fluids and elastomer materials 4.1 4.2 4.3 Mineral oils 4.4 4.5 4.6 Greases 4.7 Aggressive media 4.8 Synthetic lubricants Lube & Seal Contaminants in the fluid to be sealed 5. MATERIALS 5.1 Standard materials for Simmerring® 5.2 Special materials for Simmerring® 5.3 Materials for heavy industry 5.4 Materials for the process industry 224 228 258 258 271 277 282 285 285 285 288 289 291 293 293 293 295 296 297 297 298 298 299 302 304 306 308

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6. Boundary conditions Circumferential speeds of the shaft INFLUENCING FACTORS 6.1 6.2 6.3 Temperature 6.4 6.5 ATEX applications 6.6 Pressure 6.7 Sealing against dirt Tightness at low temperatures 7. SPECIAL DESIGNS 7.1 7.2 7.3 7.4 Designs for pressure applications PTFE sealing solutions Further solutions Circumferential Simmerring® 8. DESIGN NOTES 8.1 Shaft design Surface roughness Shaft materials Surface hardness of the counter surface Shaft machining Check the shaft lead Damage to the shaft Coaxiality Runout deviation Installation chamfer on shaft Design of the housing Roughness Tolerance Depth Chamfer Thermal expansion Split housings Stiffness Retaining claw 8.2 9. MODIFIED CATALOG SEALS Table of Contents 309 309 309 311 313 313 313 314 316 316 318 320 321 322 322 323 323 323 324 324 328 328 328 328 331 331 331 331 331 331 331 332 332 333 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 225 X E D N I

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Seals for Rotary Applications 10. PRESELECTION OF SEALS FOR ROTARY APPLICATIONS 10.1 Preselection Simmerring® 10.2 Preselection of Simmerring® cassette and combi seals 10.3 Product finder 11. HANDLING AND INSTALLATION OF RADIAL SHAFT SEALS 11.1 Goods receipt of components 11.2 Handling 11.3 Greasing of Simmerring® 11.4 Packaging of Simmerring® 11.5 Storage time 11.6 Installation in the housing bore Hammer installation Gluing in Simmerring® Wetting of the adhesive part for installation 11.7 Installation on the shaft 11.8 Installation of special designs Installation MSS1 Installation MSS7 Installation of Simmerring® with sealing lip made of PTFE Installation of Simmerring® cassette seal Installation types Installation of Simmerring® combi seal 11.9 Joining and installing open radial shaft seals on site 11.10 Replacing radial shaft seals 12. FAILURE ANALYSIS 12.1 Leakage definition – the standard, leakage terms, cause, classification Leakage Short term leakage Analysis of leakage causes: static and dynamic leakage Static leakage Dynamic leakage Lubricant Operating conditions and environmental influences Classification of leakage duration: short-term and long-term Presentation of various cases of damage to the Simmerring® Summary 12.2 Incorrect handling and corrective measures 226 338 338 344 346 358 358 358 359 359 360 361 366 367 367 368 369 369 369 371 372 373 376 378 379 381 381 381 381 381 382 382 382 383 384 387 390 391

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13. SIMMERRING® ENGINEERING 13.1 Comprehensive advice from the sealing experts 13.2 Characterization Radial shaft seal (RSS) Characterization of morphology Characterization of chemical composition Characterization of mechanical properties Seal counter surface 13.3 Modeling Functional tests on a test rig Dynamic cycle test rigs High-speed test rigs Pressure test rigs Dust and sludge test rigs Simulation 13.4 Services 14. SPECIAL SEALS 14.1 Micro-Simmerring® 14.2 Sealing caps GA, GSA Table of Contents 402 402 402 402 402 403 404 405 408 408 409 409 409 409 410 410 411 411 413 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 227 X E D N I

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Seals for Rotary Applications 1. PRODUCT OVERVIEW DESIGN DESCRIPTION MAIN APPLICATIONS PRODUCT GROUP Simmerring® BAUM/ BAUMSL Standard design with rubber- ized outer diameter and friction- optimized sealing profile Industrial gearboxes; axles (when subject to moderate dirt); electro motors; power tools; agricultural and construction machinery gearboxes PSS Special design with rubber- ized outer diameter and friction-optimized, sinusoidal sealing profile Industrial gearboxes; electro motors; power tools; robotics B1/B1SL Standard design with metal outer diameter B2/B2SL Standard design with metal outer diameter BD Partially rubberized outer diameter Industrial gearboxes; axles (when subject to moderate dirt); electro motors; power tools; heavy industry (cranes; planetary gearboxes etc.) Industrial gearboxes; axles (when subject to moderate dirt); power tools; heavy industry (cranes, planetary gearboxes etc.) Industrial gearboxes; axles (when subject to moderate dirt); power tools; agricultural and construction machinery gearboxes BABSL Pressure-resistant type with rubberized outer press fit that can be used without a back-up ring Pressurized units such as hydraulic pumps, motors and hydro dynamic couplings 228

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 72 NBR 902 ‒40 … +100 75 FKM 585 ‒25 … +160 Yes No Further information on our product portfolio Other materials possible 75 FKM 585 ‒25 … +160 No No 72 NBR 902 ‒40 … +100 Other materials possible 72 NBR 902 ‒40 … +100 Yes No Yes No Other materials possible Application specific selection of the material Material dependent No 72 NBR 902 ‒40 … +100 75 FKM 595 ‒25 … +160 Yes Other materials possible No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 229 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS Pressure-resistant type with rubberized outer press fit and low-wear sealing lip profile that can be used without a back-up ring Pressure-resistant type with rubberized outer press fit; sealing texture on the air side of the sealing lip; short, very stable sealing lip Hydrostatic drives High-pressure pumps with low speed PPS BAHD HLPS (High Low Pressure Springless lip, integrated back-up ring Heavy-duty hydraulic pumps Seal) BDSLV BA SL X6 BA SL SF BAOF B1OF Designs for special dirt requirements with non- woven dust lip Crankshaft seal Designs for special dirt re- quirements, two dust lips provide additional protection for medium contamination environments Designs for special dirt require- ments, with axial dust lip and slinger to provide additional protection in medium – high contamination environments Gearboxes; axles: pinion seal Gearboxes; axles: pinion seal Standard design with rubberized outer diameter, sealing lip without spring Electric vehicles; electro motors; sealing of pivot bearings and actuators Standard design with metal outer diameter, sealing lip without spring Electric vehicles; electro motors; sealing of pivot bearings and actuators PRODUCT GROUP Simmerring® 230

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 75 FKM 595 ‒25 … +160 Other materials possible 90 NBR 129208 88 FKM 107725 Other materials possible Application specific selection of the material Application specific selection of the material Application specific selection of the material Application specific selection of the material Yes No ‒30 … +100 ‒25 … +160 Material dependent No Material dependent No Material dependent No Material dependent No 72 NBR 902 ‒40 … +100 72 NBR 902 ‒40 … +100 Yes Yes No No No No No No No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 231 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS BDRK/ BDLK Unidirectional helix: Left-hand helix LK Right-hand helix RK Improved sealing reliability at high circumferential speeds and temperatures Unidirectional helix: for one direction of shaft rotation Bi-directional helix: for both directions of shaft rotation Engines; gearboxes; axle drives BAE SL X6 Design for separation of water suds and grease lubri- cated bearings Washing machines CTI Two-component pressure resistant seal: PTFE sealing lip on air side; rubber sealing lip on oil side Use in central tire inflation systems (CTIS) for agricultural and construction machinery BA DUO Two sealing lips, for separating two media, narrow solution, can also be used for medium dirt ingress from the outside Separation of two media Two stand- ard designs, e.g. BAUM Two standard designs, e.g. BAUM, installed back-to-back Separation of two media Micro Simmer- ring® Micro Simmerring® for rotary applications with shaft diameters 1–3 mm Use in demanding, customer- specific miniature applications such as micro pumps, micro drives and micro actuators PRODUCT GROUP Simmerring® 232

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® Application specific selection of the material Material dependent No No Application specific selection of the material Application specific selection of the material Application specific selection of the material Application specific selection of the material Material dependent No Material dependent No Material dependent No Material dependent No No No No No EPDM; NBR; FKM; FFKM; 75 Fluoro- prene® XP 41 ‒35 … +200 Material dependent No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 233 X E D N I

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Seals for Rotary Applications PRODUCT GROUP PTFE Simmerring® DESIGN DESCRIPTION MAIN APPLICATIONS B2PT B1PT Design with sealing lip made of PTFE clamped in metal housing made of stainless steel (V4A) Chemical engineering; mechanical engineering; mixers; centrifuges; pumps; rotary pressure feedthroughs Combination of metal case and PTFE excluder lip using an innovative bonding process Central tire inflation systems (CTIS); rotary feedthroughs; mechanical engineering BlueSeal Patented friction-optimized lip design with high chemical resistance Food industry; pharmaceutical industry; mechanical engi- neering; motors; retarders PTS Combination of newly devel- oped PTFE sealing lip on oil side and rubber dust lip on air side Use in special fluids for insuffi- cient lubrication and dry run- ning; in two-stroke engines; compressors; in food industry; in chemical industry BAPTSLV Combination of PTFE sealing lip with helix on the oil side and non-woven dust lip on the air side Engines; crankshaft seal BAAT Design with PTFE-coated sealing lip: coating on the air side of the sealing lip Industrial drives 234

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® Application-specific PTFE materials ‒80 … +200 Yes Application-specific PTFE materials Application-specific PTFE materials Application-specific PTFE materials Application specific selection of the material Application specific selection of the material – – – – – No No No No No No No No No No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 235 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS MSS1 Standard BAUM design, combined with an inner primary seal with sinusoidal sealing lip as one-piece solution. Design for internal dirt contamination protection Industrial gearboxes; drive technology; robotics MSS1 HS MSS3 MSS7 High-speed version of MSS1. Standard BAUM design, combined with an inner primary seal with sinusoidal sealing lip as a one-piece solution. Design for internal dirt contamination protection at high shaft speeds Modified standard BAUM design with bonded special non-woven or a PTFE extruder lip. Design for special dirt requirments Standard BAUM design combined with a rubber coated sleeve with axial dust lips as one-piece solution for special external contamina- tion requirements Industrial gearboxes; drive technology; robotics Drive technology; industrial gearboxes; agricultural and construction machinery Industrial gearboxes; drive technology PRODUCT GROUP Modular sealing systems 236

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H 72 NBR 902/ 75 FKM 585 ‒40 … +100 75 FKM 585/ 75 FKM 585 ‒25 … +160 72 NBR 902/ 75 FKM 585 ‒25 … +100 75 FKM 585/ 75 FKM 585 ‒25 … +160 72 NBR 902 ‒40 … +100 75 FKM 585 ‒25 … +160 Yes No R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P No No No No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A 72 NBR 902/ 72 NBR 902 ‒40 … +80 Yes No S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 237 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS Type 1 Type 2 Type 3 Type 4 Cassette seal with labyrinth structure, special machining of the slip ring surface on which the sealing lip acts. For road use, characterized by low contamination tendency and high speed. Safe installa- tion and handling due to the integrated contact surface Cassette seal with labyrinth structure, special machining of the slip ring surface on which the sealing lip acts. Used for applications with medium contamination and medium speed. Safe installa- tion and handling due to the integrated contact surface Cassette seal with labyrinth structure, special machining of the slip ring surface on which the seal lip acts. Use for ex- treme dirt ingress and for gen- eral applications with contami- nation. Reliable installation and handling due to the integrated contact surface Cassette seal with improved labyrinth structure, special ma- chining of the slip ring surface on which the sealing lip acts. Use in extremely harsh envi- ronments requiring higher dirt protection than Type 3. Relia- ble installation and handling due to the integrated contact surface Wheel hubs and fixed cardan shaft for commercial vehicles Wheel hubs and cardan shafts for commercial vehicles com- bining road and off-road use Wheel hubs and fixed cardan shafts for agricultural and construction machinery; rotary harrows; disc harrows; various units Harrows and fertilizer spread- ers; wheel hubs, cardan shafts for agricultural machinery; wheel hubs, cardan shafts, castors and undercarriages for construction machinery PRODUCT GROUP Cassette seals 238

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H NBR ‒40 … +80 FKM ‒25 … +120 NBR ‒40 … +80 FKM ‒25 … +120 NBR ‒40 … +80 FKM ‒25 … +120 NBR ‒40 … +80 FKM ‒25 … +120 Yes No R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Yes No Yes No No No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 239 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS HS Bearing unit Soft Unitized PTFE Cassette seal CASCO Casette seal with labyrinth structure, special machining of the slip ring surface on which the sealing lip acts. Used in ap- plications characterized by high speeds and where it is impor- tant to reduce the temperature at the main sealing lip. Reliable installation and handling due to the integrated contact surface Cassette seal in special design, material FKM, slip ring in stain- less steel. Integrated design in roller bearings to protect against contamination Cassette seal in special design with multiple axial dust lip, material FKM or NBR. Design for significant dirt ingress, the slip ring can be assembled separately from the RSS during installation Special cassette seal with PTFE sealing lip with lead, dust lip made of non-woven fabric. Good protection against dust ingress. Safe handling and easy installation Special cassette seal with axial sealing lip and double guide, material FKM, dust lip in FKM or non-woven fabric. Designed for long life, very low friction and very good re- sistance to high eccentricity. Safe handling and easy instal- lation Pinions; differentials; transmissions for agricultural machinery and commercial vehicles Grease lubricated wheel hubs Wheel hubs and pinions in axles for agricultural and construction machinery and commercial vehicles Crankshaft seals in diesel engines Crankshaft seals in diesel engines PRODUCT GROUP Cassette seals 240

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H FKM ‒25 … +120 No No R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P NBR ‒30 … +80 No No NBR ‒40 … +80 FKM ‒25 … +120 No No PTFE ‒20 … +130 No No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B FKM ‒45 … +150 FKM ‒45 … +150 No No S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 241 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS Combi Combi SF5 Combi SF6 Combi SF8 Combi seal with additional dirt deflector made of foamed polyurethane. Requires LOCTITE on the outer diameter for static sealing. Used in applications with low and predominantly dry contami- nation (if the cross-section does not permit the use of a cassette seal) Combi seal with additional dirt deflector made of hard polyurethane. Requires LOCTITE on the outer diameter for static sealing. Used in applications with medium dry and wet contamination, limited axial shaft movement or when the cross-section does not permit the use of a cassette seal Combi seal with additional dirt deflector made of hard polyurethane. Requires LOCTITE on the outer diameter to improve static seal. Use in medium dry and wet conta- mination and with axial reciprocation Combi seal with additional dirt deflector made of hard polyurethane. Integrated static seal on the outer dia meter. Use in medium dry and wet contamination and with axial reciprocation Wheel hubs; cardan shaft and power take-off shaft for agricultural machinery Wheel hubs, cardan shaft with limited axial movement and power take-off shaft for agricultural machines Axles; in particular cardan shafts in driven, steerable axles Axles, in particular cardan shafts in driven, steerable axles PRODUCT GROUP Combi seals 242

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 Yes No Yes No Yes No Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 243 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS Combi SF19 Combi SF21 Combi SF22 Combi seal with additional dirt deflector made of hard polyurethane and external rubber wiper. Integrated static seal on the outer diameter. Use for significant dry and wet contamination and axial reciprocation Combi seal with additional hard polyurethane dirt deflec- tor and outer rubber wiper. Improved polyurethane shape and materials. Use in harsh environments due to improved polyurethane shape and materials, as well as in applications character- ized by axial reciprocation Combi seal with additional hard polyurethane dirt deflec- tor and outer rubber wiper. Improved polyurethane shape and materials. Integrated static seal on outer diameter. Excellent performance in axial reciprocation. Use in harsh environments due to improved polyurethane shape and materials and in applications characterized by significant axial reciprocation Axles; in particular cardan shafts in driven, steerable axles Axles; in particular cardan shafts in driven, steerable axles Axles; in particular cardan shafts in driven, steerable axles PRODUCT GROUP Combi seals 244

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 NBR + AU ‒40 … +80 FKM + AU ‒25 … +120; max. T for AU +100 Yes No R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P No No No No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 245 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS HTS II 9535 Self-retaining PTFE shaft seal – standard version HTS II 9536 Self-retaining PTFE shaft seal – with additional dust lip HTS II 9538 Self-retaining PTFE shaft seal – with additional sealing lip HTS II 9539 Self-retaining PTFE shaft seal – Hygienic Design version Process industry; chemical industry; food industry, e.g. mixers, kneaders, pumps, compressors Process industry; chemical industry; food industry, e.g. mixers, kneaders, pumps, compressors Process industry; chemical industry; food industry, e.g. mixers, kneaders, pumps, compressors Process industry; chemical industry; food industry, e.g. mixers, kneaders, pumps, compressors HTS II 9541 Self-retaining PTFE shaft seal – with helix at the sealing lip for high dynamic recirculation capacity Process industry; chemical industry; food industry, e.g. pumps, compressors HTS II 9564 Self-retaining PTFE shaft seal – Hygienic Design version espe- cially for dry running Process industry; chemical industry; food industry, e.g. mixers, kneaders, pumps, compressors Type 9444 Robust PTFE shaft seal with worm spring on the sealing lip and an O-ring in the static part Process industry; chemical industry; general industry Type 9445 Robust PTFE shaft seal with worm spring on the sealing lip Process industry; chemical industry; general industry PRODUCT GROUP Radiamatic® HTS II PTFE shaft seals 246

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® PTFE ‒80 … +200 Yes PTFE ‒80 … +200 PTFE ‒80 … +200 Yes Yes PTFE ‒80 … +200 Yes PTFE ‒80 … +200 PTFE ‒80 … +200 PTFE ‒20 … +200 PTFE ‒20 … +200 Yes Yes Yes Yes No No No No No No Yes Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 247 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS Type 9460 Robust PTFE shaft seal with elastomer support wedge on the static part Process industry; chemical industry; general industry Type 9461 Robust PTFE shaft seal with support function on the static part – wide version Process industry; chemical industry; general industry Type 9960 Robust, pure PTFE shaft seal Process industry; chemical industry; general industry Type 9961 Robust, pure PTFE shaft seal with reinforced static part Process industry; chemical industry; general industry G61 G62 G68 G69 Self-retaining PTFE shaft seal with corrugated sealing lip – standard version Process industry; chemical industry; food industry, e.g. pumps, compressors Self-retaining PTFE shaft seal with corrugated sealing lip – with additional dust lip Process industry; chemical industry; food industry, e.g. pumps, compressors Self-retaining PTFE shaft seal with corrugated sealing lip – with additional sealing lip Process industry; chemical industry; food industry, e.g. pumps, compressors Self-retaining PTFE shaft seal with corrugated sealing lip – Hygienic Design version Process industry; chemical industry; food industry, e.g. pumps, compressors PRODUCT GROUP PTFE shaft seals Gerromatic 248

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® PTFE ‒20 … +200 PTFE ‒20 … +200 PTFE ‒20 … +200 PTFE ‒20 … +200 PTFE ‒80 … +200 PTFE ‒80 … +200 PTFE ‒80 … +200 PTFE ‒80 … +200 Yes Yes Yes Yes Yes Yes Yes Yes No No No No No No No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 249 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS RCD Wear-free, non-contact and durable labyrinth seal with high thermal and chemical stability Process industry and general industry, e.g. gearboxes R35 Standard shaft seal for housings with a flange cover Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines R36 R37 R55 Standard shaft seal with additional radial lubrication grooves Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines Standard shaft seal with additional radial and circum- ferential lubrication grooves Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines Shaft seal with additional dust lip for large diameters, especially for use in wind tur- bines Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines R58 Standard shaft seal for grease lubricated bearings RS85 Self-retaining shaft seal for oil and grease lubricated bearings Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines PRODUCT GROUP Labyrinth seals Merkel Radiamatic® 250

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® PTFE ‒80 … +200 No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B NBR HNBR FKM NBR HNBR FKM NBR HNBR FKM NBR HNBR ‒30 … +100 ‒20 … +120 ‒10 … +150 ‒30 … +100 ‒20 … +120 ‒10 … +150 ‒30 … +100 ‒20 … +120 ‒10 … +150 ‒30 … +100 ‒20 … +120 NBR ‒30 … +100 NBR HNBR FKM ‒30 … +100 ‒20 … +120 ‒10 … +150 Yes Yes Yes Yes Yes Yes, but without fab- ric Yes, but without fab- ric Yes, but without fab- ric Yes, but without fab- ric Yes, but without fab- ric Yes No S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 251 X E D N I

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Seals for Rotary Applications PRODUCT GROUP Merkel Radiamatic® Seventomatic® DESIGN DESCRIPTION MAIN APPLICATIONS RHS51 Self-retaining shaft seal for high-speed shafts Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines RPM41 Springless shaft seal for special applications, e.g. for work rolls in steel mills Heavy industry, e.g. rolling mills, ship propulsion, rudder units, tunnel boring machines, wind turbines S71 S73 S75 Innovative shaft seal for large, grease-lubricated roll- ing bearings Heavy industry, mainly for wind turbines Innovative shaft seal for large, grease-lubricated roll- ing bearings – with a sealing lip directed towards the outer diameter Innovative shaft seal for large, grease-lubricated roll- ing bearings – with addition- al dust lip Heavy industry, mainly for wind turbines Heavy industry, mainly for wind turbines Merkel® TBM TBM21 Special, large-size shaft seal without preload spring for heavy industrial applications Heavy industry, e.g. tunnel boring machines, pod drives in shipping, paper industry TBM27R Special, large-size shaft seal without preload spring for heavy industrial applications Heavy industry, e.g. tunnel boring machines, pod drives in shipping, paper industry 252

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® NBR HNBR FKM ‒30 … +100 ‒20 … +120 ‒10 … +150 Yes No NBR ‒30 … +100 Yes Yes HNBR ‒20 … +120 Yes Yes HNBR ‒20 … +120 Yes Yes HNBR ‒20 … +120 Yes Yes NBR HNBR NBR HNBR ‒30 … +100 ‒20 … +120 ‒30 … +100 ‒20 … +120 Yes Yes Yes Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 253 X E D N I

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Seals for Rotary Applications DESIGN DESCRIPTION MAIN APPLICATIONS EA EAX High-performance water guard with constant line contact of the sealing lip, even with significant shaft misalignment High-performance water guard with constant line contact of the sealing lip, even with significant shaft misalignment Heavy industry, universally suitable for many applications Heavy industry, universally suitable for many applications WA8074 Polyurethane water guard with defined sealing lip Heavy industry, universally suitable for many applications WA-A Standard water guard type A (standard version) Heavy industry, universally suitable for many applications WA-AX Standard water guard type AX (version for significant shaft misalignment) Heavy industry, universally suitable for many applications WA-S Standard water guard type S (heavy, wide version) Heavy industry, universally suitable for many applications WA-L Standard water guard type L (small, uniform profile for all diameters) Heavy industry, universally suitable for many applications PRODUCT GROUP Merkel® Enviromatic Merkel® Water Guard Merkel® V-ring 254

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® NBR HNBR FKM NBR HNBR FKM ‒30 … +100 ‒20 … +120 ‒10 … +150 ‒30 … +100 ‒20 … +120 ‒10 … +150 Yes Yes Yes Yes PU ‒30 … +110 Yes Yes NBR FKM NBR FKM NBR FKM NBR FKM ‒30 … +100 ‒10 … +150 ‒30 … +100 ‒10 … +150 ‒30 … +100 ‒10 … +150 ‒30 … +100 ‒10 … +150 Yes Yes Yes Yes Yes Yes Yes Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 255 X E D N I

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Seals for Rotary Applications SEALING CAPS PRODUCT GROUP Sealing caps DESIGN DESCRIPTION MAIN APPLICATIONS GA GSA Sealing cap with press fit – standard design (rubber out- side) Earthmoving equipment; industrial/forklift trucks; agricultural equipment; truck-mounted cranes Sealing cap with press fit – special design with rubber/ steel outside Drillings and assembly guides in housings; general mechani- cal engineering 256

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 75 NBR 99004 ‒40 … +100 75 NBR 99004 ‒40 … +100 Yes Yes No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 257 X E D N I

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Seals for Rotary Applications 2. PRODUCT GROUPS 2.1 SIMMERRING® The name Simmerring® is a registered trademark of Freudenberg. The Simmer- ring® from Freudenberg Sealing Technol- ogies (hereinafter also referred to as FST) seals drive shafts and belongs to the radial shaft seal group according to DIN. REQUIREMENTS y reliable static and dynamic tightness y high functional reliability y compatibility with the media to be sealed y tolerance to external environmental influences y low friction y easy installation FST Website Simmerring® Product catalog 258

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2. Product groups FEATURES Simmerring® with elastomer outer casing, spring-loaded sealing lip and additional dust lip based on the terms in DIN 3761, 01/1984 version. Tension spring Spring retaining collar Spring groove 1. Outer surface 2. Face chamfer Face 3. Lining 4. 5. Fixing recesses 6. Diaphragm surface (outside) 7. 8. 9. 10. Contact surface (fluid side) 11. Sealing lip 12. Sealing edge plane 13. Face side 14. Bottom 15. Spring knit line 16. Sealing edge 17. Contact surface (air side) 18. Dust lip area (diaphragm side) 19. Dust lip 20. Dust lip area (air side) 21. Diaphragm area (inside) 22. Diaphragm 23. Bottom shell 24. Stiffening ring 25. Bottom surface 26. Bottom chamfer 27. Outer casing See also → chapter “Materials and Process engineering – 6. Carrier parts“, page 123. 1 2 3 4 5 6 7 8 9 10 11 12 Fluid side 13 14 27 26 25 24 23 22 21 20 19 18 17 16 15 Air side I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 93 Characteristics of a typical Simmerring® 259 X E D N I

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Seals for Rotary Applications The main features of a Simmerring® fulfill the partial functions described below: y cylindrical outer surface (1) (→ Fig. 93) to ensure static sealing in the housing • made of elastomer with integrated OPERATING CONDITIONS The weighting of the requirements for each application and the operating con- ditions are decisive for the selection of the seal: metallic stiffening ring (24) y circumferential speed, i.e. diameter and • made of metal, mainly drawn or machined on the outer diameter (gluing may be necessary) y spring-loaded sealing lip (11) to ensure dynamic and static tightness on the shaft. Permanent further development has resulted in optimized sealing lip profiles to further increase reliability across a wide range of loads. y one or, in special cases, several dust lips (19) protect against the ingress of dirt and dust from outside. When using seals with a dust lip on the shaft, the maximum recommended circumferen- tial speed of 8 m/s must be observed. Higher circumferential speeds can also be achieved by modifying the design speed of the shaft y temperature y pressure y dirt accumulation from outside y dirt accumulation in the unit to be sealed y vibrations y media to be sealed • mineral oil and synthetic-based lu- bricating oils • mineral oil and synthetic based greases • other liquid, pasty and gaseous media whose compatibility with the gasket material must be ensured 260

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2. Product groups Play-circle  Application example BABSL/PPS APPLICATION AREAS Simmerring® are used to seal rotating shafts, predominantly in the following applications: y heavy industry (sealing of shafts in rolling mills, cement mills, large gear- boxes) y shipbuilding (sealing of stern tubes, thrusters, rudder drives) y internal combustion engines (sealing y units and manufacturing equipment of crankshafts and camshafts) in the process industry y electric motors y drive train in passenger cars and com- mercial vehicles (sealing of transmis- sions, differentials, axles, wheel hubs) y drive train in agricultural and con- struction machinery (sealing of gear- boxes, differentials, axles, wheel hubs) y industrial gearboxes (sealing of spur and worm gears, e.g. in production plants, robots or conveyor systems) y hydraulic power unit (sealing of hy- draulic pumps and hydraulic motors) y compressors y household and industrial washing machines The following illustrations contain stand- ardized sectional views of the seals. Their color representation does not represent any reference to the material used. The orientation of the seals shown does not necessarily correspond to the actual assembly position/orientation. Simmerring® BABSL Simmerring® PPS I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 94 Pressure-loadable Simmerring® in hydraulic pumps and motors 261 X E D N I

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Seals for Rotary Applications Blind shaft Sealing cap GA Drive Simmerring® BA Alternative: Drive Simmerring® BAUM eCON Alternative: Output Simmerring® MSS3 (design for food applications) Output Simmerring® MSS1 Fig. 95 Simmerring® and sealing caps in industrial gearboxes 262

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2. Product groups Cassette seal CASCO Play-circle  Further designs for use in agricultural and construction machinery Further infor- mation in the CTI Seals Sales Sheet Special design for CTI application Simmerring® combi seal Simmerring® cassette seal Special shape with axial lip Fig. 96 Simmerring® in agricultural and construction machinery I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 263 X E D N I

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Seals for Rotary Applications Cassette seal CASCO (Diesel engine only) Simmerring® BAPTSLV Fig. 97 Simmerring® in internal combustion engines Play-circle  Application example MSS1 Simmerring® cassette seal Simmerring® MSS1 Simmerring® BAUMSL Fig. 98 Simmerring® in industrial robots 264 Cassette seal CASCO (Diesel engine only) Simmerring® BAUMSLV

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t h e s e a l i n g l i p F i g . 9 9 S i m m e r r i n g ® i n s p e c i a l a p p l i c a t i o n s w i i t h h g h s p e e d a n d l o w l u b r i c a n t s u p p l y t o l B u e S e a l i S m m e r r i n g ® 2 6 5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS 2 . P r o d u c t g r o u p s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Seals for Rotary Applications Drive shaft Radiamatic® HTS II Drive shaft Gerromatic Fig. 100 Product variants Radiamatic® HTS II and Gerromatic in food and beverage indus- try applications 266

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2. Product groups EXAMPLES OF SEALING ARRANGEMENTS Fig. 101 Back-to-back application for separation of two media (with vent hole between the seals at high circumferential speeds) Fig. 102 Back-to-back application for water from outside (if necessary, special version with stainless steel spring and stiffening plate in stainless steel) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 267 X E D N I

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Seals for Rotary Applications Fig. 103 Sealing with grease lubrication (with greasing) Fig. 104 Sealing with oil lubrication 268

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2. Product groups Play-circle  Application example MSS1 Fig. 105 Sealing with shaft in the vertical position. Increased dirt accumulation at the sealing lip due to wear particles sinking in the medium Standard design e.g. Simmerring® BABSL Standard design e.g. Simmerring® BAUM Fig. 106 Sealing against vaccum (vacuum in left chamber, barrier fluid in mid chamber) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 269 X E D N I

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Seals for Rotary Applications Alternative: Simmerring® MSS3 with PTFE disc Simmerring® B2PT Fig. 107 Sealing against aggressive media (example: pump) 270 Simmerring® BAUM Alternative: Simmerring® MSS3 with PTFE disc

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2. Product groups 2.2 RADIAMATIC® SHAFT SEALS The name Radiamatic® is a registered trademark of Freudenberg. Radiamatic® shaft seals are used primarily in heavy industry. Other product groups, such as Seventomatic®, Enviromatic or TBM seals, complement the range in this application area. REQUIREMENTS y reliable static and dynamic tightness y high functional reliability y compatibility with biodegradable lu- bricants y allowance of large shaft misalignment y mastering harsh environmental con- Product catalog Radiamatic® ditions y ozone or seawater resistance y joining of seals on site y service life of up to 20 years I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 271 X E D N I

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Seals for Rotary Applications FEATURES Fig. 108 shows the typical structure of a Radiamatic® radial shaft seal for use in heavy industry. The most important feature is the lack of a steel case, which allows the seal to be cut and rejoined during field assembly. A rubber/fabric back provides the neces- sary stability of the ring. A high-perfor- mance garter spring ensures permanent contact pressure of the sealing lip on the shaft. The optional dust lip is integrated into the sealing lip and functionally de- coupled in such a way that both lips don’t interfere during operation. open side usually in the direction of the operating medium closed side usually in the direction of the environment Garter spring Sealing edge Fig. 108 Typical structure of a Radiamatic® seal Static or adhesive part (rubber/fabric) Sealing lip (pure elastomer) Dust lip (optional) 272

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2. Product groups OPERATING CONDITIONS The expectations placed on seals for use in heavy industry are high. Above all, such seals should be robust and functionally safe. Leaks in a ship’s propulsion system are often immediately visible on the water surface and lead to shutdown or an immediate and costly dock stop. Maximum reliability is the main criterion. For exam ple, seals for the main bearing in tunnel boring machines. A failure there would lead to immense costs. In wind turbines, the focus is on other properties. Here, the seals must be ozone-resistant and achieve a long service life of up to 20 years. FLEXIBLE OF SERVICE The possibility of on-site assembly without time-consuming dismantling of the system is often another customer requirement for servicing. This means that seals are supplied open or cut open on site, placed around the shaft and reassembled to form an endless ring. For this reason, a self-retaining steel case is usually not used, and a flange cover fixes the seal ring axially in the housing. APPLICATION AREAS Radiamatic® shaft seals are used wher- ever large diameters have to be sealed, extreme ambient and operating condi- tions prevail, or high shaft misalignment has to be compensated. TBM seals for tunnel boring machines, for example, can have diameters of more than 10 m. FST manufactures such rings without a joint for maximum product quality. Typical applications in the field of heavy industry: y work rolls in steel mills y main bearing seals in wind turbines y pivot bearings in pod drives for marine applications y marine propulsion systems, rudder units, stabilizers, bow thruster y main bearing seals in tunnel boring machines y rollers in the pulp and paper industry y large gearboxes The following illustrations of typical app- lications contain standardized sectional views of the seals. Their color representa- tion does not represent any reference to the material used. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 273 X E D N I

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Seals for Rotary Applications Main bearing seal Seventomatic® S71 Main bearing or upstream seal (water guard) Enviromatic EA Fig. 109 Seventomatic® and Enviromatic product variants for use in wind turbines Sealing of the work roll Radiamatic® RPM41 Water guard Enviromatic Fig. 110 Radiamatic® and Enviromatic product variants for use in steel and rolling mills Source: SMS group 274

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2. Product groups Rudder unit Swivel column Stabilizers Bow thruster Radiamatic® R35 System TBM27R Radiamatic® R35 Radiamatic® R37 System Fig. 111 Product variants Radiamatic® and TBM radial shaft seals in undersea marine applications Main bearing TBM21 Fig. 112 TBM radial shaft seals in tunnel boring machines Source: Herrenknecht AG I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 275 X E D N I

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Seals for Rotary Applications EXAMPLES OF SEALING ARRANGEMENTS Fig. 113 Sealing system for the work roll in a steel mill, consisting of a Radiamatic® RPM41 double arrangement in combination with an Enviromatic water guard Fig. 114 Sealing system for tunnel boring machines with a multiple arrangement of TBM seals 276

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2. Product groups 2.3 SIMMERRING® CASSETTE SEALS PROPERTIES y high, medium and low protection against pollution y maximum 0.5 bar permissible on the oil side (depending on the geometry of the main sealing lip) y oil sealing and protection against con- tamination for various ambient condi- tions and speeds y integrated labyrinth to protect against y no axial movement permitted during dirt y easy installation; provides low risk of damage to the seal during installation y easy handling; provides low risk of damage to the seal during handling rotation y limited axial movement permitted during seal assembly Product catalog cassette seals I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 277 X E D N I

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Seals for Rotary Applications SIMMERRING® CASSETTE SEAL TYPE 1, 2, 3 PROPERTIES y speed from high to low, change from y increased protection against dirt, change from type 1 to type 3 y seal for both directions of shaft rota- tion y diverse application possibilities in type 1 to type 3 practice y more complex labyrinth, change from type 1 to type 3 Sealing lip for oil/grease sealing Socket with special surface treatment Inner diameter with elastomer layer Fig. 115 Simmerring® cassette seal type 3 Outer diameter: Elastomer for high static tightness Metal for reliable assembly alignment Inner labyrinth profile for dust-/water retention Axial buffer to maintain the reciprocal position of the two components during assembly Pregreased chambers Cassette Seal Typ 3Simmerring® cassette seal Fig. 116 Simmerring® cassette seal in driven axles 278

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2. Product groups SIMMERRING® CASSETTE SEAL TYPE 4 PROPERTIES y less limitation on speed, temperature and pressure compared to cassette seal type 3 y extremely high protection against dirt y seal for both directions of shaft rota- tion y extended applicability in the field, due to the improved application pos- sibilities in highly contaminated envi- ronments Axial buffer to maintain the reciprocal position of the two components during assembly Sealing lip for oil/grease sealing Socket with special surface treatment Inner diameter with elastomer layer Fig. 117 Simmerring® cassette seal type 4 Outer diameter: Elastomer for high static tightness Metal for reliable assembly alignment Internal labyrinth profile for dust/water retention Pregreased chambers Simmerring® cassette seal type 4 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 118 Use of the Simmerring® cassette seal 279 X E D N I

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Seals for Rotary Applications SIMMERRING® CASSETTE SEAL HS y good protection against pollution y seal for only one or both directions of shaft rotation PROPERTIES y inner diameter of metal and elastomer y high speeds and temperatures permis- y oil/grease sealing at high rotational speeds and temperatures y for high heat dissipation from the seal- sible Outer diameter: Elastomer for high static tightness Sealing lip for oil/grease sealing Working surface of the sealing precision trimmed Inner diameter: Metal content for better heat dissipation ing edge Pregreased chamber Outer diameter: Metal for reliable assembly alignment Inner labyrinth profile for dust/sludge retention Pregreased chambers Fig. 119 Simmerring® cassette seal HS (high speed) Simmerring® cassette seal Cassette HS HS Fig. 120 Use of the Simmerring® cassette seal as a pinion seal in axles 280

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2. Product groups SIMMERRING® CASSETTE SEAL CASCO y high speeds and temperatures permis- sible y seal for only one direction of shaft ro- PROPERTIES y axial sealing lip: extremely low wear and tation (CW or CCW) y protection against pollution low friction y low sensitivity to axial/radial eccen- tricity Axial sealing lip Inner diameter: Metal content for reliable assembly Fig. 121 Simmerring® cassette seal CASCO Outer diameter: Elastomer for high static tightness Metal for reliable assembly alignment Hook lip for catching Inner labyrinth profile for dust/sludge retention I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 122 Use of Simmerring® cassette seals CASCO on the crankshaft 281 X E D N I

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Seals for Rotary Applications 2.4 SIMMERRING® COMBI SEALS Product catalog combi seals PROPERTIES Simmerring® combi seals are “unitized” seals for medium speeds and for im- proved protection against contamination from the environment. They tolerate axial misalignment of the shaft during rotation. They consist of: y a sealing ring (standard design or design BA DUO) y a dirt repellent made of polyurethane y a “Unitized” housing SIMMERRING® COMBI SEAL SF19 y higher axial shaft misalignment per- PROPERTIES y more flexible dirt deflector made of poly urethane that follows the wave dynamics y integrated elastomer dirt deflector, which is the first element to prevent dirt from entering the housing missible y very high protection against contam- ination y for environments with high require- ments Outer diameter: Metal for reliable assembly alignment Rubber sealing lip for oil/grease from the inside Inner elastomer dust lip against water/dust from the outside Fig. 123 Simmerring® combi seal SF19 Outer diameter: Elastomer for high static tightness Dirt wiper, which is the first component that protects against the penetration of dirt Dirt deflector made of compact polyurethane against water/dust from outside 282

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2. Product groups SIMMERRING® COMBI SEAL SF21 PROPERTIES y optimized shape of the dirt deflector made of high-quality polyurethane, which is now more sensitive to the ec- centricity of the shaft and enables better tracking of the shaft y higher axial shaft misalignment per- missible compared to SF5, SF6, SF8 y integrated dirt deflector made of hardened elastomer compound, which is the first element to prevent dirt from entering the housing y higher protection against dirt com- pared to SF19 y for harshest environments Outer diameter: Metal for reliable assembly alignment Rubber sealing lip against oil/grease from inside Inner dust lip from elastomer against water/dust from outside Fig. 124 Simmerring® combi seal SF21 Outer diameter: Elastomer for high static tightness Outer wiper made of hardened composite material, as the first component it protects against the penetration of dirt Dirt deflector made of high-quality, compact Freudenberg polyurethane with optimized shape for better shaft tracking properties I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 283 X E D N I

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Seals for Rotary Applications SIMMERRING® COMBI SEAL SF22 PROPERTIES y optimized shape of the dirt deflector made of high-quality polyurethane, which is now less sensitive to eccen- tricity of the shaft and allows better tracking of the shaft y counter-rotating solution allows highest permissible axial shaft misalignment y integrated dirt deflector made of hard- ened elastomer compound, which is the first element to prevent dirt from entering the housing y higher protection against dirt com- pared to SF19 y for harshest environments combined with demanding axial misalignment Outer diameter: Metal for reliable assembly alignment Rubber sealing lip for oil/grease from the inside Counter rotating solution enables increase of the permissible axial play of the shaft Outer diameter: Elastomer for high static tightness Outer wiper made of hardened composite material, which is the first component that protects against the penetration of dirt Dirt deflector made of high-quality, compact Freudenberg polyurethane with optimized shape for better shaft tracking properties Inner dust lip made of elastomer against water/dust from outside Fig. 125 Simmerring® combi seal SF22 Simmerring® combi seal Fig. 126 Simmerring® combi seal in driven axle 284

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3. Sealing mechanism using the example of the Simmerring® 3. SEALING MECHANISM USING THE EXAMPLE OF THE SIMMERRING® The Simmerring® seals a shaft against the housing of a device (e.g. → Fig. 94, page 261 and → Fig. 95, page 262): • decomposition products • lubricant supply • internal contamination y dynamic and – when the shaft is at standstill – static sealing between sealing lip and shaft y static sealing and ensuring a tight fit of the seal between the outer jacket of the seal and the housing bore Environment and operation y temperature y dust and dirt y run and shutdown periods y cleaning media 3.1 INFLUENCING PARAMETERS The sealing behavior and the service life of the seal are influenced by a complex system of mutually influencing variables: The device to be sealed y shaft • diameter • speed • eccentricity • surface • axial movement • material • manufacturing process • chamfer design • hardness • coating y housing • surfaces • center offset to the shaft • tolerances • material • installation space • chamfer design y medium • temperature • chemical effects • viscosity • lubricity • pressure The Simmerring® y design and tolerances • of the adhesive part • of the sealing lip y radial force y material • hardness • wear resistance • resistance to chemical swelling and shrinkage • friction properties • sealing ability etc. 3.2 DYNAMIC SEALING FUNCTION The most important functional area of the Simmerring® is the sealing edge in contact with the surface of the rotating shaft (→ Fig. 127). The sealing mechanism in the contact area of the sealing lip is of decisive impor- tance for the sealing function. It is depend ent on a tribological system, (seal, shaft, and medium) as well as: y the design of the sealing lip y the properties of the elastomer mate- rial y the nature of the shaft surface y the medium to be sealed y the operating conditions (e.g. height impact, vibrations, kinematics ...) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 285 X E D N I

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Seals for Rotary Applications Oil side Width of sealing gap Shear Height of the sealing gap Dirt Grease Fig. 127 Contact zone between sealing edge and shaft of a Simmerring® CHARACTERISTICS OF THE SEALING LIP A wide range of experience is required for dimensioning the characteristic values. The dimensioning is carried out by the manufacturer depending on the material, size, geometry and application of the Simmerring®. Geometrical parameters Overlap (→ Fig. 128) The inner diameter of the sealing lip is always smaller than the shaft diameter in the free, untensioned state. Radial force FR Air side β Oil side α hF Diameter in the free state shaft diameter d Fig. 128 Dimensions at the profile of the sealing lip 286 The overlap (also preload) is the difference between these two dimensions and is between approx. 0.8 mm and 2.5 mm, depending on the shaft diameter. The radial pre-load tuning of the geometry influences the flexibility of the lip: y flexible and long sealing lips for high tolerances of coaxiality and concen- tricity (for permissible values, see → Fig. 151, page 328 and → Fig. 152, page 329) y short profile with position stabilization relative to the shaft for pressure appli- cations The characteristic value for the distance between the center point of the spring and the sealing edge is the spring effec- tive distance hF: y if the hF dimension is too small, the lip may tip over, especially in the case of shaft run-out and non-flat installation y a too large hF dimension results in a deflection of the lip and thus a wide contact of the lip with the shaft as well as a wide running track

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3. Sealing mechanism using the example of the Simmerring® Sealing lip angle The sealing lip angles influence the seal- ing mechanism by acting on the contact pressure ratios: y oil side: steep angle α y air side: flat angle β Radial force The radial vector force exerts an angular pressure on the shaft due to the expan- sion of the sealing lip in the installed state. This sum of tangential tensile and bending forces of sealing lip and spring is determined by the: y influence of the elastomer: The mod- ulus of elasticity depends on the ma- terial, temperature and aging. Thus, the decrease of the radial force during operation depends on temperature, time and possible interactions with the medium to be sealed (→ chapter “Materials and Process engineering – Anti-Ageing Agents“, page 109 y influence of the sealing lip profile: Sealing lip geometry and elongation, i.e. overlap y influence of the tension spring: mate- rial (standard material: spring steel wire EN 10270-1-SM, in special cases stainless steel according to EN 10270-3), temperature, length, coil diameter, wire thickness A low radial force value should be striven for in order to keep friction and wear of the seal low. However, a minimum radial force is required to ensure the dynamic sealing function over the long term. Sealing function in the contact zone of the sealing lip The radial force of the sealing lip, in con- junction with the dimensioning of the sealing lip angle and effective spring dis- tance, pro duces an asymmetrical or bias contact pressure distribution (→ Fig. 129): y pressure maximum and steep rise on the oil side y flat drop on the air side Radial force FR Radial force FR Oil side Air side Oil side Air side Sealing lip Sealing lip pmax Contact pressure distribution pmax Direction of shaft rotation Fig. 129 Deformation structure of the elastomer in the contact surface of the sealing lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 287 X E D N I

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Seals for Rotary Applications This deformation structure, together with the rotating shaft, generates a pumping effect on the medium to be sealed in the direction of the oil side. This micropump effect is decisive for the seal- ing function. 3.3 SEALING LIPS WITH HELIX (SPECIAL DESIGN) To increase the sealing capacity at high temperatures and circumferential speeds, the air side of the sealing lip is provided with a helix for special designs (→ Fig. 130). This asymmetrical distribution of contact pressure is of great importance for the function of the seal. The contact pressure distribution and the circumferential force generated by the rotating shaft lead to a characteristic deformation structure of the contact surface of the seal lip (→ Fig. 129). A suitable elastomeric material for the seal is characterized by the formation of a distinct structure of the “distortion”. The structures that promote the micro- pumping effect are formed at the seal edge during the run-in. Therefore, a run- ning-in or wear-in phase is necessary for the seal to generate the surface roughness required for the pumping effect. This is why both the upper and lower shaft sur- face-finish must be controlled. Oil side Sealing edge Direction of rotation of the shaft seen from the air side of the seal: right = RK right helix left = LK left helix WK Bi-directional helix Pumps with direction of rotation to Pumps with direction of rotation to the right towards the oil side the left towards the oil side Fig. 130 Helix on the air side of the sealing lip (β) 288

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3. Sealing mechanism using the example of the Simmerring® Map-Marker-Exclamation Always avoid dry running Angled helix ribs oriented in the direction of rotation extend into the contact zone of the sealing lip. They reinforce the pumping effect of the micro-lead of the elastic material. Since the orientation of the ribs of the single helix is tied to a direction of rota- tion, an arrow on the bottom side of the helix rings indicates the permissible di- rection of rotation. If use for both directions of rotation is nec- essary, bi-directional helix is used. This is less effective than the uni-directional helix. All helix rings have a finished sealing edge, i.e. produced in the forming tool. Radial shaft seals with return helix cannot be used reliably in combination with pres- surization on the medium side. Standard Simmerring® from the catalog program are designed without return helix. Simmer- ring® seals with a machined sealing edge (e.g. BAUM profile type) exhibit stable seal- ing behavior and therefore do not require return helix structures. 3.4 LUBRICATION AND FRICTION Sufficient supply of lubricant to the seal is decisive for the service life and reliabil- ity of the seal. The better the lubricating and wetting properties of the fluid to be sealed, the lower coefficient of friction, and the lower the wear. The greater the supply of lubricant for the sealing edge, the lower the temperature in the sealing gap between the sealing edge and the ro- tating shaft surface. Even at standstill, the fluid to be sealed and at the same time used for lubrication penetrates the unevenness of the shaft and sealing lip due to capillary forces. The direct contact of the sealing lip with the shaft is predominant. Starting and then increasing rotational movements lead, similar to a sliding bear- ing, from the state of boundary friction via mixed friction to predominant hydro- dynamic friction. Important note! Elastomer seals must never run dry. When installing elastomer seals, the shaft or the seal must be lightly greased or oiled. For applications with fluids that have limited lubricating properties (e.g. water), individual technical advice should be obtained from FST. During the design phase, it should be en- sured that sufficient lubricant is available at the sealing edge during the first revo- lutions (e.g. through holes and channels). Some types of rolling bearings, including tapered roller bearings, can generate a considerable pumping effect during op- eration. As a result, different fluid supplies are possible relative to the sealing point, which can have a negative influence on the lubrication of the sealing edge. Remedy: design measures to ensure sufficient lubricant supply to the sealing point under all operating conditions and installation positions. Parameters influ- encing the contact pressure of the seal- ing edge on the shaft surface and the lubrication conditions at the sealing lip affect the friction performance of the sealing point. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 289 X E D N I

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Seals for Rotary Applications The minimum friction power is deter- mined by the minimum contact pressure of the sealing lip, which ensures the dy- namic sealing function of the sealing point. Optimum seal performance and life-cycles are achieved by precisely tun- ing in the seal design to the application parameters. The reference values for friction power were determined with complete lubri- cation of the sealing lip (→ Fig. 131). The values given here only indicate the order of magnitude of the friction and refer to a well-lubricating engine oil. They can therefore not be used as absolute values for individual cases and are not transfer- able to applications with industrial gear oils. The constant demand for low friction and at the same time reliable sealing function requires the continuous further development of sealing materials and seal design. ] s t t a w [ r e w o p l a n o i t c i r F 400 300 200 100 0 0 m m 0 6 3 Ø m m 0 2 3 Ø m m 0 0 4 Ø aft h S U/min 0 0 5 m m 0 28 Ø U/min 0 0 0 1 min / U 0 5 2 d e e p S m m 200 Ø m m 160 Ø mm 140 Ø mm 120 Ø U/min 0 0 0 2 3 000 U/min 4 000 U/min 6 000 U/min 8 0 0 0 U/min 1 0 0 0 0 U / m in U / m i n 0 0 0 U / m i n 0 0 5 1 0 0 2 100 m m Ø m 80 m Ø m m m m m m 0 0 0 0 m m 6 5 4 3 2 0 m m Ø Ø Ø Ø Ø 1 0 m m Ø 5 10 15 20 25 Circumferential speed [m/s] Fig. 131 Reference values for the frictional power of a Simmerring® without dust lip in SAE 20 engine oil, at T = +100 °C, example: Shaft Ø d1 = 80 mm, speed n = 3,000 rpm, friction power approx. 150 W 290

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3. Sealing mechanism using the example of the Simmerring® 3.5 STATIC TIGHTNESS AND y chamfers on the adhesive part (see FIT IN THE BORE The outer casing (also known as the ad- hesive part) of the Simmerring® has the following tasks: y static sealing in the housing bore y ensuring a tight fit in the bore y enabling proper and easy installation of the seal Depending on the installation conditions and operating conditions, different versions of the adhesive part are used (→ Fig. 132). For trouble-free assembly, the following points must be taken into account: DIN 3760) y press fit allowances to the nominal dia- meter depending on the design of the outer surface according to DIN 3760 For requirements on the design of the housing bore, refer to section 8.2 “Design of the housing” (→ page 331). Simmerring® with rubber covered outer di- ameter – Type BA (A according to DIN 3760) y offers the best conditions for static sealing y for split housings y for housings made of light metal with increased thermal expansion y for pressure applications y for low-viscosity and gaseous NOMINAL HOUSING Ø [mm] PRESS FIT ALLOWANCE FOR METALLIC OVERLAP FIT PRESS FIT ALLOWANCE FOR ELASTOMER OVERLAP FIT [mm] [mm] > 0 35 50 80 120 180 300 400 ≤ 35 50 80 120 180 300 400 500 Smooth fit, fine and medium creasing Coarse creasing 0.23 ±0.08 0.23 ±0.08 0.28 ±0.08 0.28 ±0.08 0.35 ±0.10 0.35 ±0.10 0.43 ±0.13 0.43 ±0.13 0.30 ±0.10 0.30 ±0.10 0.35 ±0.10 0.35 ±0.10 0.43 ±0.13 0.43 ±0.13 0.50 ±0.15 0.50 ±0.15 0.15 ±0.05 0.15 ±0.05 0.18 ±0.05 0.20 ±0.05 0.23 ±0.05 0.25 ±0.05 0.29 ±0.06 0.29 ±0.06 Tab. 13 Typical overlap fit allowance for designs B1, B2 and BA based on DIN 3760, part 1 as of 09/1996 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 291 X E D N I

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Seals for Rotary Applications Map-Marker-Exclamation Care must be tak- en to prevent any adhesive material from coming in contact with the sealing lip Simmerring® with rubber covered outer diameter – Type BA...X7 outer diameter with grooves y enables easy assembly y reduces the possibility of retracting or skewing the seal y enables higher press-fit allowance to increase the safety of the static seal, especially in housings with high thermal expansion Simmerring® with partially rubberized outer diameter – BD design (special design on request – not part of catalog range) combines the advantages of reliable static sealing by the elastomeric part with press fit by the metallic part of the outer diameter Simmerring® with metallic outer diame- ter – Type B1 and B2 (B/C to DIN 3761) Production of the metallic, smooth outer surface by deep drawing and possible finishing by turning or grinding. To coun- teract corrosion, a corrosion protection oil is applied to finished components: y for requirements of particularly tight and exact fit in the bore y important note: In unfavorable condi- tions such as • rough bore surfaces • low viscosity and creeping media or • pressure applications • the use of an additional sealing com- pound (adhesive) may be necessary in the contact area of the press fit y limited use only in housings with in- creased thermal expansion or split housings y when pressed into light metal housings, there is a risk of scoring in the bore y Type B2 (with additional stiffening ring) has higher structural integrity and radial stiffness for: • larger dimensions • difficult and awkward installations Material of the metal stiffening part and the metal housing y for all standard applications: non-alloy steel DIN EN 10027-1 y for special cases: stainless steel DIN EN 10088 BA Outer diameter covered with elastomer Very good static sealing function B1 Outer diameter of the plate girder without elastomer covering Limited static sealing function B2 Outer diameter without elastomer covering 2 sheet metal supports for high stability Limited static sealing function BD Outer diameter with elastomer seat and metal seat Customized design Fig. 132 Designs of the adhesive part of the Simmerring® 292

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4. MEDIA TO BE SEALED 4. Media to be sealed Map-marker-edit No disclosure of test results using various test programs to determine, among other things, the lubrication and wetting behavior of the tested fluid (→ “13. Simmerring® Engineering”, page 401). The client is the owner of the test results. Test results can therefore not be passed on to third parties. Against this back- ground, the lubricant manufacturer (customer) can, if necessary, provide in- formation on tests carried out. 4.2 INTERACTIONS BETWEEN FLUIDS AND ELASTOMER MATERIALS The chemical/physical effects of the media on the sealing materials have a decisive in- fluence. The reactions or interactions are accelerated, especially with increasing tem- perature (see also → chapter “Materials and Process engineering – Influence of media: Storage tests“, page 154 and → chapter “Materials and Process engineer- ing – 12. Chemical resistance“, page 180). The materials can harden or soften under the influence of media (→ Fig. 133) (see also → “12. Failure analysis”, page 381): y hardening due to aging processes caused by the media, especially at el- evated temperature y softening by swelling due to the influ- ence of the media 4.1 FLUID AND MATERIAL SELECTION The fluid to be sealed largely determines the selection of the material and thus also the design of the radial shaft seal. Sealing is possible against liquid, pasty and, in exceptional cases, gaseous media. Sealing against lubricants, e.g.: y mineral oils y synthetic oils y mineral oil-based greases y synthetic greases Sealing against working fluids, e.g.: y hydraulic oils according to DIN 51524 y fire-resistant hydraulic fluids according to VDMA 24317 and VDMA 24320 y silicone oils with minimal lubricating properties Sealing against aggressive media with low lubricating properties (in special cases), e.g.: y acids y lyes y organic solvents The constantly increasing load on the device due to higher power density has resulted in permanent adaptation and new development of the lubricants. Seal- ing compatibility is a decisive criterion here. Freudenberg Sealing Technologies offers to perform oil compatibility tests. As part of the release tests, static insertion tests are carried out to determine the chemical and physical interactions. In addition, dy- namic tests with oil seals are completed I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 293 X E D N I

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Seals for Rotary Applications ] % [ e g n a h C An initial, often sufficiently accurate, as- sessment of the effect of the media to be sealed on the elastomer material is made by determining the mechanical values on test samples in the laboratory. Before and after static immersion of a standardized elastomer test sample in the corresponding fluid, values such as hardness, elongation at break, tensile strength and volume are measured and the change documented (DIN 53521). The influence of different lubricants, especially under the influence of high temperature, is clearly illustrated by the example of the change in elongation at break, (modulus of elasticity) (→ Fig. 134). In order to assess the service life of a par- ticular elastomer material and thus of a seal, a change in elongation at break < 50% is taken as a guide value. For more information, see also → chapter “Materials and process engineering – 8. Testing methods“, page 143. +20 0 ‒20 ‒40 ‒60 ‒80 ‒100 Hardness Volume Tensile strength Elongation at break 0 200 400 600 800 1000 Storage time [h] Fig. 133 Change in characteristic values of an NBR material as a function of storage time; storage in SAE 80 gear oil at +100 °C 294

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4. Media to be sealed in ever newer combinations. As a result, static and dynamic compatibility testing with elastomer materials is becoming increasingly important. In this context, Freudenberg Sealing Technologies recom- mends observing the specific information provided by oil manufacturers and, in case of doubt, checking compatibility with the selected materials. 4.3 MINERAL OILS y used in motor vehicles according to API and MIL classifications: engine oils, manual transmission oils, hypoid transmission oils, ATF oils for automatic transmissions y used in a wide range of applications in gear manufacturing: C, CL, CLP gear oils according to DIN 51517 Low-alloy mineral oils generally show good compatibility with the materials used for Simmerring®. Increasing demands on the mineral oils lead to higher additivated oils ] % [ k a e r b t a n o i t a g n o e n l i e g n a h C +20 0 ‒20 ‒40 ‒60 ‒80 ‒100 Change of elongation at break = ‒50% Multipurpose grease Hypoid gear oil 85 W 90 ASTM oil No. 1 Air Gear oil SAE 80 Multigrade engine oil 15 W 40 0 200 400 600 800 1000 Storage time [h] Fig. 134 Exemplary representation of the change in elongation at break of NBR when stored in various fluids at +100 °C I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 295 X E D N I

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Seals for Rotary Applications Hypoid gear oils High-pressure lubricating oils with a pro- portion of special additives, especially EP additives, are used to improve lubricity and prevent seizure of bearings and gears. Additives are used to optimize the tribolog- ical processes in the area of tooth flanks in gear teeth and the contact points in bear- ings. However, these additives can also lead to deposits in the area of the sealing point at the sealing edge and the shaft surface. In addition, undesirable reactions in the tribological system of the sealing point may occur under certain circum- stances. Remedy: For the use of highly additivated lubricants, there are specially adapted elastomer materials or designs/products. The standard material 72 NBR 902 is largely insensitive to hypoid oils if the temperature of the fluid does not exceed +80 °C (→ Tab. 15, page 301). FKM materials can withstand higher ther- mal loads and are more chemically resist- ant to various hypoid oil substances. Sim- merring® made of 75 FKM 585 - BAUM, BAUMSL or special designs – can be used up to the specified temperature limits. The FST materials experts will be pleased to help with any queries. If possible, the sealing lip of the selected design should be designed for low fric- tion. This reduces the increase in temper- ature in the area of the sealing edge and the tendency for deposits to form in the sealing edge area. 4.4 SYNTHETIC LUBRICANTS Reasons for using partially and fully syn- thetic lubricants (→ Tab. 15): y better viscosity behavior y suitable for higher temperatures y good aging resistance y higher efficiencies Base oils generally show good compati- bility. However, in combination with the additives used, different interactions with the elastomer materials used are possible. When used with the material 75 FKM 585 and synthetic lubricants (especially poly- glycol oils), increased sealing edge wear may occur in the oil sump temperature range of below +60 °C. In this special application, a special FKM material (e.g. 75 FKM 170055) should be provided. The FST materials experts will be pleased to help with any queries. Important note: Before using lubricant- elastomer combinations in series pro- duction or under operating conditions that are not yet known, it is recommend- ed to carry out a trial or compatibility test. The first step should be a static laboratory test according to DIN 53521 over at least 168 h (preferably 1,008 h). Reliable infor- mation on the compatibility of fluid and elastomer can only be provided by per- forming a dynamic compatibility test lasting 1,008 or 2,016 hours, as has been shown in many cases. The intensive co- operation between seal and lubricant manufacturers has proven valuable here. Map-marker-edit For highly additi- vated lubricants, the temperature limits of 72 NBR 902 are restricted. Map-Marker-Exclamation Use of unknown combinations 296

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4. Media to be sealed I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I DEVELOPMENT OF THE DEVICE CHANGE OF INFLUENCES y Improved efficiency y Longer service life y Noise reduction y Lifetime lubrication y Extended lubrication intervals y Higher speeds y Higher temperatures y Higher mechanical stress on the components y Increased oil contamination y High acceleration DEVELOPMENT OF SYNTHETIC OR SEMI-SYNTHETIC, HIGHLY ADDITI- VATED LUBRICANTS y High temperature resistance y Aging resistant y Improved VI behavior y Good cold flow properties y Good solubility y Biodegradable oils Fig. 135 More demanding sealing point INCREASING DEMANDS ON SIMMERRING® y Thermal y Mechanical y Chemical/physical y Better dirt seal 4.5 LUBE & SEAL The demands on sealing systems are con- stantly increasing (→ Fig. 135). It is there- fore necessary to continuously investi- gate the influencing parameters. This is being done at Freudenberg Sealing Tech- nologies in close cooperation with Klüber, the in-house lubricant specialist based in Munich. The aim of the “Lube & Seal” pro- ject is to use optimally matched sealing material and lubricant (see also → chapter “Services – Lube & Seal”, page 12: y optimized chemical/physical interac- tions between elastomer and lubricant y minimized friction and thus of power loss y minimized wear y increased reliability y increased the service life 4.6 GREASES For sealing against grease, the conditions for dissipating frictional heat are less favorable than for liquid media. Remedy: If the circumferential speed exceeds approx. 50% of the permissible values for grease (material 72 NBR 902, → Fig. 136, page 310), consider switch- ing to oil lubrication. For the sealing of grease- lubricated, slowly running shafts, it is recommended that the space be filled as completely as possible with grease in accordance with the specifica- R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Map-marker-edit Possible conversion to oil lubrication S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 297 X E D N I

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Seals for Rotary Applications 4.8 CONTAMINANTS IN THE FLUID TO BE SEALED Impurities can be, for example: y molding sand residues or metal chips from the production of cast housings y abrasion of rotating parts, e.g. of bronze worm wheels in worm gears y decomposition products from the fluids Depending on the load, these contami- nants influence the sealing and wear be- havior of the seals. Remedy: ensure that the housing is as clean as possible. If con- tact of the sealing lip with contaminants is unavoidable (e.g. in the case of vertical shafts), a collecting or centrifugal plate should be connected in series and a series seal used. In many applications, the MSS1 design with its upstream sinusoidal seal- ing lip on the fluid side has proved suc- cessful. tions of the bearing manufacturer. In ap- plications with relubricating systems (e.g. lubricating nipples), it is advisable, with regard to sealing capacity and low wear, to install the seal on one side of the bear- ing arrangement so that the sealing lip faces outwards (note: do not use a seal with a dust lip at this sealing point). In this way, overpressure in the sealed space can be avoided in the event of heating during operation or relubrication. For sealing with insufficient lubricant supply or against poorly lubricating media such as water or washing lye, a separate grease reservoir must be provided to lubri- cate the sealing and dust lip. The volume in the space between the sealing lip, dust lip and shaft should be filled approx. 40% with grease. Greases with a high oil separating capac- ity are particularly suitable for lubricating the sealing liprolling like bearing greases of consistency class NLGI 1 or NLGI 2 ac- cording to DIN 51818 with a minimum rolling penetration of 310 or 265 accord- ing to DIN 51804 or ASTM D217-52. 4.7 AGGRESSIVE MEDIA For the sealing of aggressive media, such as y acids, alkalis y silicone oils for viscous couplings y chemical resistant fluorinated oils, the resistance to the seal material must be clarified in each case (→ “5. Materials”, page 299). 298

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5. MATERIALS 5. Materials The selection and use of the material for the sealing lip are the most important criteria for the function and reliability of the sealing system. The properties of the individual materials are defined in speci- fications for the minimum or maximum physical values and their change after specified tests,. e.g. ASTM 2000. The de- cisive factor for the function, the sealing ability, can only be ensured by intensive and wide-ranging tests or within the framework of experience from series applications.. See also → chapter “Materials and Process engineering – 3. General material selec- tion and descriptions“, page 48 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P NBR HNBR FKM PTFE ACM PU Steering S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Engines Axles, gears Industrial gearboxes Hydraulic power units Heavy industry Process industry Washing machines Further mechanical engineering Standard material Special material Not used State of the art Trend Tab. 14 Application areas of materials for radial shaft seals S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 299 X E D N I

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Seals for Rotary Applications ACM POLYACRYLATE ELASTOMER Special material for use primarily in auto- motive engineering; on request. ACM is characterized by good properties in applications with high vibration loads. FKM FLUOROELASTOMER Preferably used for high chemical and thermal resistance requirements and generally for high circumferential speeds (→ Fig. 136, page 310), e.g. in y heavy industrial applications y two-stroke engines y engines in general y gearboxes, hydraulic power units y drive train of commercial vehicles y drive train of agricultural and con- struction machinery Broad range of applications and has longer expected service life compared to NBR materials. For material variants, media resistance and temperatures, see → Tables “Stand- ard/Special Materials for Simmerring®,” “Materials for Heavy Industry,” “Materials for Process Industry Applications” starting on page 302. HNBR HYDROGENATED NBR ELASTOMER HNBR is more heat resistant than NBR. In addition, HNBR offers better wear behav- ior than NBR in dynamic applications. HNBR is also resistant to hot water and shows good low-temperature and high-temperature behavior from ‒40 to +140 °C. In sealing technology, the signif- icantly more cost-intensive material HNBR is used primarily where higher tempera- tures and/or mechanical strength are re- quired. HNBR offers wide-ranging appli- cation possibilities, particularly in the process industry. HNBR is suitable in the process industry, the beverage industry and applications in contact with very greasy media. NBR NITRILE BUTADIENE ELASTOMER Widely used in mechanical engineering and heavy industry, in industrial gear- boxes, hydraulic power units (hydraulic pumps, hydraulic motors), two-stroke engines, washing machines and partly in the drive train of agricultural and con- struction machinery. For material variants, media resistance and temperatures, see overviews starting on page 302. PTFE POLYTETRAFLUOROETHYLENE The thermoplastic, non-polar polymer has a number of advantages that make it unique in sealing technology: y highly resistant to chemicals y very low coefficient of friction y can be used over a very wide temper- ature range without any problems y favorable dry running behavior y individual compounds have best di- electrical properties (conductive PTF E compounds on request) 300

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5. Materials PU POLYURETHANE Increasingly used in heavy industry due to positive properties such as: y high sealing effect y good friction behavior y robust, easy handling The properties of the various materials determine their most important areas of application (→ Tab. 14): PROPERTIES NBR HNBR FKM PTFE ACM PU Abrasion resistance Good Very good Very good Moderate Moderate Very good High temperature resistance Moderate max. +100 °C Good max. +140 °C (max. +100 °C continuous temperature) Very good max. +200 °C (max. +160 °C continuous temperature) Very good max. +200 °C (max. +160 °C continuous temperature) Good (max. +140 °C continuous temperature) Moderate max. +110 °C Low temperature resistance Down to –40 °C Down to –40 °C Down to –25 °C Down to –80 °C Down to –30 °C Down to –30 °C Oil resistance Good Good Very good Very good Good Good Tab. 15 Properties of elastomer materials Important notes: High temperature resistance refers to the maximum temperature resistance of the material in question. It is NOT the maximum operating temperatures (e.g. oil sump temperature or ambient tempera- ture). Low temperature resistance refers only to a limited extent to the minimum application temperature. The application is very much dependent on the viscosity of the fluid to be sealed at low tempera- tures, the radial runout of the shaft and other operating conditions (→ “6.4 Sealing behavior at low temperatures”, page 119). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 301 X E D N I

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Seals for Rotary Applications 5.1 STANDARD MATERIALS FOR SIMMERRING® MATERIAL Color Density [g/cm3] (DIN 53479) Hardness [Shore A] (DIN 53505) Stress value/ 100% [N/mm2] Tensile strength [N/mm2] Elongation at break [%] (DIN 53504) (DIN 53504) > 10 (DIN 53504) > 300 – – – – – – 72 NBR 902 75 FKM 585 1) 75 FKM 595 1) PTFE 10/F56101 Dark brown Auburn Dark gray Blue 1.43 75 > 4 2.06 75 > 4 > 10 > 175 2.01 75 > 3.5 7.5 > 200 Classification according to ASTM D 2000 M2 BG 710 M2 HK 710 M2 HK 810 Temperature range at sealing lip [°C] –40/+100 –30/+200 –30/+200 –80/+200 MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] ASTM D 2000 M2 BG 710 M2 HK 710 M2 HK 810 M2 HK 710 – M2 BG 710 Permissible low temperature –40 –30 –30 –30 –80 –40 +100 +100 +80 +100 +100 1) 1) +150 +150 +140 +150 +150 1) 1) +150 +150 +140 +150 +150 1) 1) +150 +150 +140 +150 +150 1) 1) +150 +150 +140 +150 +150 1) 1) +100 +100 +80 +100 +100 1) 1) Mineral lubricants Engine oils Gear oils Hypoid gear oils ATF oils Greases Synthetic lubricants Polyalkylene glycols (PAG) Polyalphaolefins (PAO) 302

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5. Materials MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] Mineral hydraulic fluids HLP according to DIN 51524 part 2 +100 HLVP according to DIN 51524 part 3 +100 +150 +150 +150 +150 +150 +150 +150 +150 +100 +100 Biodegradable hydraulic fluids HETG rapeseed oil ** HEES – synthetic esters HEPG polyglycols*** Fire resistant hydraulic fluids Group HFA*** Group HFB*** Group HFC*** Group HFD **** Other media      – – + + +   – + + +   – + + +   – +150 +150 +150 + + + + + +150 +150      – – – –   – –   – –   +100 +90 +   –   – – – I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Heating oil EL and L +90 Brake fluid DOT 3/DOT 4 Water*** Suds*** Air +100 +200 +200 +200 +200 +120 The values given are based on a limited number of tests on standard test specimens (2 mm sample plates) from laboratory production. The data determined from finished parts may deviate from the above values depending on the manufacturing process and the part geometry. The low temperature limit depends on the shaft run-out. 1) When using FKM materials in synthetic lubricants polyalkylene glycols (PAG) and polyalphaolefins (PAO), the max- imum operating temperature must be determined by a test or hydraulic power unit run. ** Application limits specified by the fluid *** Additional lubrication recommended **** Resistance depends on HFD type resistant, generally not used for these media +  conditionally resistant – not resistant  on request S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 303 X E D N I

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Seals for Rotary Applications 5.2 SPECIAL MATERIALS FOR SIMMERRING® MATERIAL CLASSIFICATION ACC. TO ASTM D2000 HARDNESS (SHORE A) COLOR APPLICATION EXAMPLES 70 NBR 110558 M2 BG 710 70 NBR 260866 M2 BG 710 75 FKM 170055 M7 BG 814 82 NBR 132919 M6 BG 814 70 FKM 260737 M7 BG 814 75 FKM 106200 M2 BG 71 80 NBR 94207 M7 BG 810 90 NBR 129208 M7 BG 910 75 HNBR 260258 M2 BG 714 80 HNBR 172267 M7 BG 814 70 70 75 80 70 75 80 90 75 80 Black Black Washing machines Washing machines Dark brown Drive technology e.g. PG oils Blue Low temperature applications Black Low temperature applications Black Black Seawater/ship waves Black Special pressure applications Black Special pressure applications, power steering systems MATERIAL 70 NBR 110558 70 NBR 260866 75 FKM 170055 82 NBR 132919 70 FKM 260737 75 NBR 106200 80 NBR 94207 90 NBR 129208 75 HNBR 260258 80 HNBR 172267 MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] ASTM D 2000 M2 BG 710 M2 BG 710 M7 BG 814 M6 BG 814 M7 BG 814 M2 BG 710 M7 BG 810 M7 BG 910 M2 BG 714 M7 BG 814 Permissible low temperature Mineral lubricants –30 –30 –30 –40 –30 –40 –25 –30 –30 –30 Engine oils +100 +100 150+ +100 +150 +100 +100 +100 +120 +120 +100 +100 +150 +100 +150 +100 +100 +100 +120 +120 +80 +80 +140 +80 +140 +80 +80 +80 +100 +100 +100 +100 +150 +100 +150 +100 +100 +100 +120 +120 +100 +100 +150 +100 +150 +100 +100 +100 +120 +120 Gear oils Hypoid gear oils ATF oils Greases 304

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5. Materials MATERIAL 70 NBR 110558 70 NBR 260866 75 FKM 170055 82 NBR 132919 70 FKM 260737 75 NBR 106200 80 NBR 94207 90 NBR 129208 75 HNBR 260258 80 HNBR 172267 MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] Synthetic lubricants Polyalkylene glycols (PAG) Polyalpha- olefins (PAO) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) 1) Mineral hydraulic fluids HLP acc. to DIN 51524 part 2 HLVP acc. to DIN 51524 part 3 +100 +100 +150 +100 +150 +100 +100 +100 +100 +100 +100 +100 +150 +100 +150 +100 +100 +100 +100 +100 Biodegradable hydraulic fluids HETG rapeseed oil**  HEES – synthetic esters  HEPG polyglycols***  Fire resistant hydraulic fluids    – Group HFA*** Group HFB*** Group HFC*** Group HFD **** Other media Heating oil EL and L Brake fluid DOT 3/DOT 4 +90 +90 – – Water*** +90 +90       – + + +   – +150 + –       – –  –  + + +   – +150 + –       – –      – –      – – +90 +90 +90 –  –  –       – –  –       – –  –  I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 305 X E D N I

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Seals for Rotary Applications 5.2 SPECIAL MATERIALS FOR SIMMERRING® MATERIAL 70 NBR 110558 70 NBR 260866 75 FKM 170055 82 NBR 132919 70 FKM 260737 75 NBR 106200 80 NBR 94207 90 NBR 129208 75 HNBR 260258 80 HNBR 172267 MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] Suds*** Air +90 +90         +100 +100 +200 +100 +200 +120 +100 +100 +130 +130 1) When using FKM materials in synthetic lubricants polyalkylene glycols (PAG) and polyalphaolefins (PAO), the max- imum operating temperature must be determined by a test or hydraulic power unit run. ** Application limits specified by the fluid *** Additional lubrication recommended **** Resistance depends on HFD type resistant, generally not used for these media conditionally resistant + ⊗ – not resistant  on request 5.3 MATERIALS FOR HEAVY INDUSTRY MATERIALS 7 6 1 V U A 3 9 7 9 2 B R B N 0 6 1 0 5 0 1 R B N 0 7 5 6 5 5 4 2 R B N 0 8 1 4 2 B R B N 0 8 1 6 4 5 4 2 R B N 5 8 3 0 2 B R B N 5 8 7 4 2 B R B N 5 8 8 4 2 B R B N 5 8 7 6 4 U R B N H 5 7 0 4 0 0 1 R B N H 5 8 8 9 6 K M K F 5 6 0 7 6 K M K F 0 7 2 6 6 5 4 2 M K F 5 8 3 8 6 K M K F 0 9 2 4 1 V U A 5 9 MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] ASTM D 2000 – –       M2 BG 910        Permissible low temperature –30 –20 –40 –20 –30 –30 –25 –30 –20 –20 –20 –20 –20 –10 –20 –20 Mineral lubricants Engine oils Gear oils Hypoid gear oils ATF oils Greases + + + + +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +150 +150 +150 +150 +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +130 +130 +150 +130   +80 +80 +80 +80 +80 +80 +80 +80 +100 +100 +130 +130 +150 +130 + + +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +130 +130 +150 +130 +110 +110 +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +130 +130 +130 +130 Synthetic lubricants   +80 +80 +80 +80 +80 +80 +80 +80 +120 +120 +130 +130 +130 +130   +80 +80 +80 +80 +80 +80 +80 +80 +120 +120 +130 +130 +130 +130 Polyalkylene- clycols (PAG) Polyalphaole- fins (PAO) 306

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5. Materials 7 6 1 V U A 3 9 7 9 2 B R B N 0 6 1 0 5 0 1 R B N 0 7 5 6 5 5 4 2 R B N 0 8 1 4 2 B R B N 0 8 1 6 4 5 4 2 R B N 5 8 3 0 2 B R B N 5 8 7 4 2 B R B N 5 8 8 4 2 B R B N 5 8 7 6 4 U R B N H 5 7 0 4 0 0 1 R B N H 5 8 8 9 6 K M K F 5 6 0 7 6 K M K F 0 7 2 6 6 5 4 2 M K F 5 8 3 8 6 K M K F 0 9 MATERIALS 2 4 1 V U A 5 9 MEDIA TO BE SEALED WITH INDICATION OF PERMANENT TEMPERATURE [°C] I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Mineral hydraulic fluids HLP acc. to DIN 51524 part 2 HLVP acc. to DIN 51524 part 3 +110 +110 +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +130 +130 +130 +130 +110 +110 +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +130 +130 +130 +130 Biodegradable hydraulic fluids HETG rapeseed oil ** HEES – synthetic esters HEPG polyglycols*** +60 +70 +60 +60 +60 +60 +60 +60 +60 +60 +80 +80 +80 +80 +80 +80 +80 +90 +80 +80 +80 +80 +80 +80 +80 +80 +80 +80 +100 +100 +130 +100 +40 +60 +60 +60 +60 +60 +60 +60 +60 +60 +100 +100 +55 +55 +80 +55 Fire resistant hydraulic fluids Group HFA*** +50 +70 +55 +55 +55 +55 +55 +55 +55 +55 +55 +55 +60 +60 +60 +60 Group HFB*** +50 +70 +50 +50 +50 +50 +50 +50 +50 +50 +60 +60 +60 +60 +60 +60 Group HFC*** +40 +60 +60 +60 +60 +60 +60 +60 +60 +60 +60 +60 +60 +60 +60 +60 Group HFD ****  + – – – – – – – – – – +100 +100  +100 Other media Heating oil EL and L Brake fluid DOT 3/DOT 4 Water*** Suds*** Air   +80 +80 +80 +80 +80 +80 +80 +80 +80 +80 +100 +100 +100 +100 – – – – – – – – – – – – – – – – +40 +80 +100 +100 +100 +100 +100 +100 +100 +100 +120 +120 +120 +120 +120 +120 – – +60 +60 +60 +60 +60 +60 +60 +60 +100 +100     +110 +110 +100 +100 +100 +100 +100 +100 +100 +100 +130 +130 +200 +200 +200 +200 ** Application limits specified by the fluid *** Additional lubrication recommended **** Resistance depends on HFD type resistant, generally not used for these media conditionally resistant + ⊗ – not durable  on request R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 307 X E D N I

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Seals for Rotary Applications 5.4 MATERIALS FOR THE PROCESS INDUSTRY MATERIAL COLOR CROSSLINKING/ FILLER 4 0 0 2 / 5 3 9 1 ) C E ( . G E R 6 0 0 2 / 3 2 0 2 ) C E ( . G E R ) C E ( . G E R 1 1 0 2 / 0 1 70 EPDM 291 Black Peroxide 70 EPDM 335 Black Peroxide 70 NBR 438 Black Peroxide 75 Fluoroprene® XP 45 Blue Peroxide PTFE E202 Beige Ekonol PTFE G223 White Glass PTFE Y002 Beige Special PTFE G116 White Glass PTFE G224 Blue Special Quantum® PTFE F18245 Quantum® PTFE F53722 Brown Special White opaque Glass                       Y R A T I N A S A 3 S D R A D N A T S      E E R F I D A            1 5 F S N  A D F            ) I O V V N I ( 8 8 . H C I V S S A L C P S U R E T P A H C P S U ) O R T I V N I ( 7 8 / 6 0 8 4 B G 9 8 6 9 B G       The multitude of different applications in the food and beverage, pharmaceutical and chemical industries, such as fill- ing lines or mixers, place different demands on the right sealing solution. Radial shaft seals made of specially developed materials conform to the relevant industry-specific standards. Drive shafts in the process industry 308

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6. INFLUENCING FACTORS 6. Influencing factors The processes in the tribological system of the radial shaft seal are influenced by various operating and design parameters. These include, for example: y circumferential speed of the shaft y temperature y pressure The following section explains these para meters and their implications. Calculation of the circumferential speed “v” of the shaft according to the formula: v (m/s) = Shaft Ø D (mm) x Speed (1/min) x 60000 Permissible circumferential speeds accord- ing to DIN 3760 (→ Fig. 136). The values given are guide values. The prerequisites are sufficient lubrication and good heat dissipation. Under less favorable condi- tions, correspondingly lower values apply. 6.1 BOUNDARY CONDITIONS If several limit values of the permissible operating conditions coincide, e.g. y if the elastomer material is not correct- ly selected for the operating conditions y the max. permissible circumferential speed (→ Fig. 136) y the max. permissible temperature y the max. permissible pressurization y and especially with sparse lubrication or limited heat dissipation the application limits of the radial shaft seals will be reached and exceeded, and the service life will be limited. 6.2 CIRCUMFERENTIAL SPEEDS OF THE SHAFT The circumferential speed, formed from the speed and diameter of the shaft, is the determining influencing variable for determining the design and material of the radial shaft seals. Three ranges characterize the permissible circumferential speeds: y use of the material NBR y use of the material FKM y outside both ranges, the use of stand- ard Simmerring® is not possible. As soon as the operating point lies out- side the ranges for FKM and NBR, special designs are required. These must be requested individually via your contact person Important notes: The values taken from the diagram (→ Fig. 136) are based on an application with good lubricant supply using an SAE 20 en- gine oil with good lubricating and wet- ting properties. The values are therefore not transferable to lubricants with lower lubricating and wetting properties. If other lubricants are used, significantly different limit values can sometimes be expected in the limit range. When using a component with a dust lip with overlap to the shaft, the maximum circum ferential speed is 8 m/s (depending on the remain- ing operating conditions) → Special de- signs see page 122. Map-marker-edit Higher speeds possible by trim- ming or venting the dust lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 309 X E D N I

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Shaft speed [rpm] 30 000 15 000 10 000 9000 8000 7000 6000 5000 4500 4000 FKM 3500 ] s / m [ d e e p s t f a h S 3000 2500 2000 1500 1000 NBR Grease 500 200 ... 500 Seals for Rotary Applications Speed limit design Limit: see diagram No dust lip or trimmed dust lip without contact to the shaft vented dust lip with contact to the shaft ] s / m [ d e e p s l a i t f n e r e m u c r i C 40 30 20 10 Limit: 15 m/s Limit: 8 m/s Standard dust lip with contact to the shaft 5 0 0 25 50 100 150 Fig. 136 Guide values for the permissible circumferential speed for Simmerring® (guide values) made of the materials NBR (72 NBR 902) and FKM (75 FKM 585) with sealing of engine oil SAE 20 and sufficient lubricant supply (diagram is not applicable with lubricant supply by spray oil or oil mist due to low cooling - diagram not relevant for pressure seals) Shaft diameter [mm] 310

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6. Influencing factors As the pressure on the sealing lip increases, so does the overtemperature at the seal- ing edge. For guide values when using a solid shaft and good lubrication, please refer to → Fig. 139. The use of a Simmerring® with a dust lip overlapping the shaft surface results in excess temperatures of up to > 20 °C in the tribological system. Exceeding the permissible temperatures for the respective materials leads to: y heavy wear y early hardening of the sealing lip and y shortened service life 6.3 TEMPERATURE Due to the relative velocity between the sealing edge and the shaft surface and the resulting friction, the temperature at the sealing edge is always higher than in the oil sump. This overtemperature (temperature dif- ference between oil sump and contact temperature in the sealing gap between sealing edge and shaft surface) depends on the following parameters: y rotational speed or circumferential speed y heat dissipation (via the shaft and/or via fluid exchanged between oil sump and sealing gap) y shaft surface y contact pressure of the sealing lip on the shaft surface (influenced by housing overpressure, design of the seal, elas- tomer material and other parameters) y physical and chemical properties of the fluid to be sealed The fill level of the fluid to be sealed in the unit influences the heat dissipation and thus the temperature in the sealing gap. The range between the upper and lower limit curves (→ Fig. 137) shows the possi- ble influence on the excess temperature depending on the given heat dissipation: y lower limit curve for full shaft immersion y upper limit curve for 25% shaft recircu- lation The ranges given for the individual media are based on their different lubricity and heat conductivity. As the rotational speed or circumferential speed increases, the excess temperature at the sealing edge rises (→ Fig. 138). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 311 X E D N I

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Seals for Rotary Applications ] C ° [ t e r u a r e p m e t r e v O 120 80 40 0 0 Grease Gear oil SAE 90 Engine oil SAE 20 40 80 120 160 Shaft diameter [mm] Fig. 137 Overtemperature at the sealing edge of a Simmerring® when sealing different media. Oil bath temperature +100 °C, speed 3,000 rpm ] C ° [ t e r u a r e p m e t r e v O 80 60 40 20 0 Speed 6.000 rpm 3.000 rpm 1.500 rpm 0 20 40 60 80 100 120 140 160 Shaft diameter [mm] Fig. 138 Overtemperature at the sealing edge of a Simmerring® as a function of speed. SAE 20 engine oil, oil bath temperature +100 °C, oil level: center of shaft ] C ° [ e r u t a r e p m e t r e v O 80 60 40 20 0 0 1.5 bar pressureless 20 40 60 80 100 120 140 160 Shaft diameter [mm] Fig. 139 Overtemperature at the sealing edge of a Simmerring® with unpressurized sealing and pressurization, SAE 20 engine oil, speed 3,000 rpm, oil level: center of shaft 312

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6. Influencing factors 6.4 TIGHTNESS AT LOW TEMPERATURES Elastomers lose elasticity with decreasing temperature until they reach the glass state. Depending on the material, the glass transition temperature is between ‒10 and ‒40 °C. The freezing process is reversible, i.e., the material returns to its original properties with increasing tem- perature. In the case of rotary seals, heat is gener- ated by the friction occurring during movement. At temperatures at which there is already a risk of hardening due to freezing, the frictional heat can be suffi- cient to keep the seal elastic or to bring it into a functional state quickly enough after the start of movement. Due to the generally high viscosity of the lubricant, leakage at low temperatures is very rare in practice. Exceptions occur with very high shaft deflections and with fluids that have a low viscosity even at low temperatures (e.g. fuels). 6.5 ATEX APPLICATIONS y the ATEX Directive 2014/34/EU came into force on April 20th 2016 y the ATEX Directive applies to the design of electrical, explosion-protected equipment, devices and protective systems for intended use in explosion- protected areas Hot surfaces (EN 1127-1) Among other things, it is described that ignition can occur in explosive atmos- pheres if hot surfaces (e.g. shafts) come into contact with them. Depending on the circumferential speed, standard Simmer- ring® with a tarnishing dust lip can reach shaft surface temperatures of > +120 °C for a short time. Please contact the Freudenberg Sealing Technologies repre- sentative responsible for you. 6.6 PRESSURE As the pressure increases, so does the pressure on the sealing lip and conse- quently the disturbance of the hydrody- namics under the sealing edge, as well as the friction and overheating at the sealing edge. The pressure load p and the circumferen- tial speed v determine the application lim- its of the seals (→ Fig. 144 and → Fig. 145, page 317). If the respective limit values are exceeded, premature wear, premature hardening of the sealing lip and shortened service life must be expected. Standard Simmerring® are mainly designed for pressureless oper- ation or for use at very low pressures. Maximum pressure load: 0.02 to 0.05 MPa (→ Tab. 16). If the unit becomes so warm during operation that the enclosed air becomes pressurized, the installation of a vent valve is recommended. For a limited range of these loads, the use of the standard BABSL design is recommended. The characteristic feature of this seal is a short, yet flexible sealing lip. This design reduces the increase in the contact pres- sure of the sealing lip and thus the friction power. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 313 X E D N I

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Seals for Rotary Applications PRESSURE DIFFERENCE [bar] max. MAXIMUM PERMISSIBLE SPEEDS [rpm] 0.5 0.35 0.2 Up to 1000 Up to 2000 Up to 3000 Tab. 16 Maximum permissible shaft speeds when pressurized SHAFT AT CIRCUMFERENTIAL SPEED [m/s] max. 2.8 3.15 5.6 6.7 SEALING AGAINST DIRT For sealing against dirt, dust and moisture on the air side, the use of a Simmerring® with dust lip is recommended. At circumferential speeds > 8 m/s, care must be taken to ensure that the dust lip does not make contact with the shaft. Before installation, the space between the sealing lip and the dust lip must be filled approx. 40% with grease to lubricate the dust lip and prevent corrosion of the shaft. Another option for protecting the sealing point against external contamination is the VRM01 or VRM02 upstream element (→ Fig. 141). 314

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6. Influencing factors > 8 4 … 8 < 4 → Fig. 167, page 359 U ] s / m [ v d e e p s l a i t n e r e f m u c r i C I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P weak medium strong (fordable) Friction contacts Grease filling Fig. 140 Simmerring® for reliable dirt sealing Dirt accumulation on air side S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B BAUMSL in combination with VRM 01 VRM 01 starting on housing with BAUMSL VRM 02 starting on housing with BAUMSL Fig. 141 Simmerring® in combination with upstream element S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 315 X E D N I

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Seals for Rotary Applications 7. SPECIAL DESIGNS Map-marker-edit Back-up ring drawing available Play-circle  Application example BABSL/PPS In addition to the standard BAUM/ BAUMSL design, other design and material versions are available for additional areas of appli- cation. 7.1 DESIGNS FOR PRESSURE APPLICATIONS USE/APPLICATIONS For pressurization > 0.5 bar, the catalog range includes the BABSL and PPS de- signs. Special customer-specific designs are available for higher pressure loads (→ Fig. 143). If no Simmerring® BABSL is available, the sealing lip can be supported by a back-up ring in the case of designs without a dust lip. Pressure p The back-up ring, which must be made of metal, must be precisely adapted to the sealing lip profile (→ Fig. 142). For this purpose, you can request a support ring drawing from your technical contact at Freudenberg Sealing Technologies. Pre- cise specification of the design is required. For higher pressure/velocity loads, special shapes with a higher but narrower func- tional range are used in the p-v diagram (→ Fig. 145). PPS DESIGN Further development of the proven BABSL design has boosted the performance range by up to 25%. The Simmerring® PPS (Premi- um Pressure Seal) has a patented sealing edge design that keeps the lip profile sta- ble up to twice the pressure load level of conventional designs. The dust lip provides protection against dirt entry and other con- taminants, preventing damage to the sealing edge. The specially developed sealing edge design makes the PPS ex- tremely suitable for high velocity (up to 15 m/s) and medium pressure (up to 40 m*bar/s) applications. Fig. 143 Installation of a Simmerring® with back-up ring BABSL PPS BAHDSN BAHDOF Fig. 142 Designs for pressurizable Simmerring® 316

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7. Special designs I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A BABSL R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H ] r a b [ e r u s s e r P 10,0 9,0 8,0 7,0 6,0 5,0 4,0 3,0 2,0 1,0 0 Ø 1 6 0 m Ø 8 0 m m m Shaft Ø 40 m m Ø 20 mm R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 0 1000 2000 3000 4000 5000 6000 7000 Shaft speed [rpm] Fig. 144 Guide values: permissible pressure in the hydraulic power unit for Simmerring® (BABSL design) ] r a b [ e r u s s e r P 1,0 0,9 0,8 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0 PPS Ø 40 mm Ø 60 mm Ø 80 mm 0 1000 2000 3000 4000 5000 6000 7000 Shaft speed [rpm] Fig. 145 Guide values: permissible pressure in the hydraulic power unit for Simmerring® (PPS design) 317 X E D N I

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Seals for Rotary Applications BAHD DESIGN The BAHD is a specially developed and field-proven high-pressure seal that can withstand pressures up to 150 bar. The max. circumferential speed is 2 m/s, but the max. speed and max. pressure cannot be combined. The sealing lip has a very stable geometry, which can be designed with lubrication grooves (BAHDSN). For extreme conditions, the BAHD can also be designed with a dust lip. The BAHD+ is a further development and made of HNBR material. The design withstands pressures up to 175 bar. y the frictional heat occurring in the operating state has a re-deforming effect on the expanded sealing lip y a spring can therefore be dispensed with y contact of the sealing lip made of PTF E on the shaft with a track width of ap- prox. 2.5 mm y the dynamic sealing behavior is partly limited, depending on the design When using PTFE seals without integrat- ed spiral helix, minor leakage must be expected, depending on the operating conditions. 7.2. PTFE SEALING SOLUTIONS CONDITIONS OF USE y thermal load capacity from ‒130 °C to +200 °C SIMMERRING® WITH SEALING LIP MADE OF PTFE y circumferential speed: up to max. 30 m/s y “stick-slip” free behavior compared to USE/APPLICATIONS PTFE is a proven material with high ther- mal resistance that does not interact with the lubricant. Use of Simmerring® with a sealing lip made of PTFE: y when the thermal operating limits of elastomers are exceeded y in case of chemical/physical incom- patibility of elastomer and lubricant TYPICAL APPLICATIONS y pumps in the chemical industry/process engineering y engines (crankshaft) y hydrostatic drives (use of HF C fluids) y gearboxes of all types y rotary pressure feedthrough (air) SEALING MECHANISM y achievement of the required contact force due to the memory effect inherent in the material elastomers y suitability • in case of insufficient lubrication and dry running • in water mixed with detergents • in vapors, cooling liquids, emulsions • in mineral oils, synthetic oils and greases y resistance against aggressive media, such as acids, alkalis, solvents; exceptions are ele- mental fluorine and molten alkali metals y deployability • for sealing powders, granulates, adhesives and resins, but abrasive materials may cause premature sealing edge wear • for components with a conveying structure on the sealing lip, can only be used in one direction of rotation y application • pharmaceutical and food sector • applications in the chemical industry Map-Marker-Exclamation Low leakage possible when using PTFE seals without integrat- ed spiral helix 318

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7. Special designs BAAT DESIGN y spring-loaded seal made of elastomer with a sealing edge made of PTF E (film). A metallic stiffening ring ensures, among other things, stability during installation and when pressurized y application: two- and four-stroke en- gines, hydrostatic drives, rotary pressure feedthroughs B2PT DESIGN y PTF E sealing sleeve: carbon filled y material: PTF E 561/10 firmly clamped between two metal housings, precisely centered to the outer diameter y O-ring made of FKM for static sealing y metal housing: DIN EN 10088 PTS DESIGN y partially rubberized housing for opti- mum static tightness in the housing, no gluing necessary y sealing lip made of special PTF E, vulcan- ized to the elastomer, thus no static leakage possible y integrated dust lip y PTF E sealing lip with and without spiral helix y pressure up to 10 bar, circumferential speeds up to 20 m/s y use in pressure-loaded, hydrostatic drives, among others y also suitable for sealing biodegradable liquids and HF C liquids SPECIAL DESIGN y sealing lip made of special PTF E, vul- canized to the elastomer, with special back-feed helix to minimize friction y dust lip optionally made of a nonwoven to prevent the formation of negative pressure behind the sealing edge and minimize friction y use primarily as a crankshaft seal in engines B2PT PTS Special design BAAT BlueSeal Fig. 146 Simmerring® with PTFE sealing lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 319 X E D N I

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Seals for Rotary Applications BLUESEAL y PTF E disc is bonded to a metallic carrier by a special manufacturing process. This ensures static and dynamic sealing at the same time. Very low axial height possible. Could replace any engine seal if there is no particular dirt y application: Food industry, pharma- ceutical industry, general mechanical engineering, engines Additional application-specific PTFE com- pounds are available for all Simmerring® with PTFE sealing lip, e.g. for use in the food industry. SPECIALLY FOR THE PROCESS INDUSTRY The following designs (→ Fig. 147) with single sealing lip or in double arrange- ment are high-performance radial shaft seals whose sealing lips are arranged dif- ferently depending on the version and subsequent task. The available materials comply with food-specific approvals such as Reg. (EC) 1935/2004, Reg. (EC) 10/2011, FDA§177.2600, NSF 51 or GB 4806 and GB 9685. RADIAMATIC® HTS II y low contact forces of the sealing lip ensure low friction and low heat input y secure fit due to clamping ring tech- nology GERROMATIC y sinuous sealing lip enables high pressure load y maximum tightness for wet running 7.3 FURTHER SOLUTIONS y design with additional axially oriented dust lip: at higher circumferential speeds, the axial dust lip forms a “labyrinth” against the dirt, with the correspondingly adapted centrifugal plate rotating with the shaft y design with two radial dust lips: par- tially built-in additional metal part to resist ingress of dirt y design of a combination of two seals built into each other: several additional dust lips y Simmerring® cassette seal of different design: against highest dirt load y Simmerring® combi seal with additional dirt deflector made of wear-resistant polyurethane With each additional dust lip in contact with the counter surface, the frictional power increases and with it the heat generated. It must therefore be checked whether optimum heat dissipation is en- sured. HTS II 9538 HTS II 9535 Gerromatic G61 Gerromatic G69 Fig. 147 Special designs Radiamatic® HTS II and Gerromatic for the process industry Map-Marker-Exclamation Increasing friction due to additional dust lip 320

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7. Special designs This is achieved by using stiffer sealing lip profiles, e.g. Simmerring® of the BABSL design, or by using a special spring. 7.4 CIRCUMFERENTIAL SIMMERRING® When installing seals in rotating housings, the lower contact pressure or lifting of the sealing lip due to centrifugal force must be taken into account. For permissible limit speeds at which the sealing lip lifts off standard Simmerring®, see → Fig. 148. If the limit speed is exceed- ed, the contact pressure of the sealing lip must be increased. ] m p r [ d e e p s g n s u o H i 4000 3500 3000 2500 2000 1500 1000 500 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B 0 0 40 80 120 160 200 240 Shaft diameter [mm] Fig. 148 Example speeds for rotating Simmerring® on fixed shafts. Always consult with the technical contact person S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 321 X E D N I

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Seals for Rotary Applications 8. DESIGN NOTES 8.1 SHAFT DESIGN The design of the shaft in the area of the counter surface of the sealing lip has a decisive influence on the sealing function and the service life of the sealing system (→ Fig. 149). The recommendations and limit values listed in this section are based on experi- ence gained with solid shafts (solid shaft). The use of thin-walled hollow shafts results in limited dissipation of frictional heat from the sealing gap. The same applies to shaft sleeves or spacer rings which are joined to the shaft as a counter surface. The gap between the running surface and the shaft provides an additional in- sulating layer. This applies in particular when an adhesive layer is used for fastening or for improving the static tightness. Repair sleeves available on the market are used if the shaft surface has the following characteristics when repairing a sealing point: y shaft inlet in the area of the sealing edge position of the sealing point y sufficiently large axial offset of the new sealing ring not possible y damage to the shaft surface y corrosion of the shaft surface It should be noted that, depending on the design of the shaft sleeve used, the effec- tive running surface diameter is signifi- cantly increased. No damage, pores, scratches Wear resistance: abrasion adhesion damage to the surface tribooxidation Roughness Rmax Rz Ra Rp Topography of the shaft surface: grinding smooth rolling hard turning Exact concentricity Economic production Wetting through the medium Lead-free Sufficient protection against corrosion Good heat dissipation Fig. 149 Requirements for the design of the shaft for Simmerring® 322

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8. Design notes SURFACE ROUGHNESS Permissible values: Rz = 1.0 ... 5.0 µm Ra = 0.2 ... 0.8 µm Rmax < 6.3 µm For compressive load > 0.1 MPa: Rz = 1.0 ... 3.0 µm Ra = 0.2 ... 0.4 µm Rmax < 6.3 µm Exceeding or falling below the specified values can lead to premature wear and consequently to leakage. Excessive roughness causes high prema- ture wear of the sealing lip and high leak- age. If the surface roughness is too shallow, there is a risk of limited wetting of the shaft with the fluid to be sealed, especially at higher circumferential speeds. This can lead to dry running and thus to increased wear, thermal overload, cracking and material hardening in the area of the sealing edge. Tolerances for mating Diameter tolerance: Tolerance for roundness: ISO h 11 IT 8 SHAFT MATERIALS Suitable are: y steels commonly used in mechanical engineering, e.g. C35 and C45 y cast materials such as nodular graphite and malleable cast iron (prerequisite is no cavities and pore depth < 0.05 mm) y sprayed-on hard metal coatings (pre- requisite is a pore depth < 0.05 mm and good adhesion to the base material) y coatings by CVD and PVD processes as well as anodically applied coatings are positively evaluated The roughness values must also be main- tained after the coating process. Non-ferrous materials, e.g. MS 58 H, should be used for water sealing at low circum- ferential speeds. Stainless steels, e.g. ma- terial no. 1.4300 and 1.4112 (hardenable) are better. Ceramic bushings are very wear-resistant and have proved successful in special cases. Prerequisites are compli- ance with the roughness values and good adhesion to the base material. Generally not suitable y hard chrome coatings (because of the partially uneven wear) y plastics (because of the very low thermal conductivity, the resulting disturbed heat transport and the large temper- ature increase at the sealing edge, as well as the possible softening) SURFACE HARDNESS OF THE COUNTER SURFACE The service life of the seal depends on the surface hardness of the running surface on the shaft. The hardness should be at least 45 HRC (DIN 3760). For contaminated media, dirt from out- side or circumferential speeds > 12 m/s: y hardness on the surface approx. 60 HR C y effective depth of hardening > 0.3 mm Deviations from these general guidelines may be decided on a case-by-case basis, provided the entire load spectrum is known. Please contact the person responsible for you at Freudenberg Sealing Technologies. Map-marker-edit Consultation in individual cases I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 323 X E D N I

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Seals for Rotary Applications SHAFT MACHINING The correct machining of the shaft is a decisive factor for the functionality of the sealing system. Plunge grinding The predominantly used process is plunge grinding, since it ensures the required lead on the shaft when the grinding process is completely finished. Process parameters and their effects can be found in → Tab. 17. Hard turning Hard turning is predominantly used for shafts that rotate in only one direction. The lead generated on the shaft surface by turning, which corresponds to a single or multi-start thread, can influence the conveying behavior of the sealing point. The success of the use of this process de- pends on the following parameters: y compliance with the process parame- ters (→ Tab. 18) y conveying direction of the shaft sur- face structure. It must be coordinated with the direction of rotation present during operation (conveying direction in the direction of the fluid space) y conveying effect of the shaft surface structure. It must not be too strong, otherwise there is a risk that the lubri- cant film between the sealing edge and the shaft will rub off, resulting in dry running The reason for using this process is its economy. If the “hard turning” process described above is to be used, hydraulic power unit tests are absolutely necessary. Other methods are y roller burnishing y blasting y honing, superfinishing and emerizing y tangential turning These processes are only to a small extent suitable for a mating surface for Simmer- ring®. CHECK THE SHAFT LEAD In the case of ground shafts, orientation- free finishing of the running surface is ab- solutely essential. This should be checked for the shaft lead. The lead test method described in → Fig. 150 has proven itself in practice. It should be noted that not all critical lead struc- tures can be detected. The thread used for the test should be replaced regularly in order to achieve the most repeatable result possible. Experience has shown that a lead angle of the lead structure of less than 0.05° is generally not considered to be function- ally critical. In addition, shaft surfaces can be charac- terized optically according to the current state of the art. Restrictions on the size of the component must be observed. See also → “13. Simmerring® engineering”, page 401. Note: FST supports you in defining and verifying optimum machining parame- ters in the form of services. 324

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8. Design notes PROCESS PARAMETERS IMPACT ADVANCE NOTE Speed ratio grinding wheel/workpiece Workpiece speed Grinding wheel speed Can create a lead Not integral e.g. 10.5:1 Can create a lead 30 … 300 rpm 1,500 … 1,700 rpm Dressing feed Influences the pitch of the conveying thread < 0.02 mm/revolution Check during the process Tool and workpiece must rotate in opposite directions Pull off in one direction only Dressing tool Can create a lead Four grain diamond, single grain diamond Most common causes for a surface with a lead Dressing delivery Influences roughness values and lead structure Approx. 0.02 mm Most common causes for a surface with a lead Firing time Influences cross section of the conveying thread Complete firing at least Most common causes for 30 s a surface with a lead Plunging depth May cause leakage > as Rmax from the previ- ous machining process Most common causes for a surface with a lead Grinding wheel/grain roughness parameters 60KL8V25 (white) Influences the Example: 60 … 100 high-grade corundum Rmax, Rz and Ra Dimensions 400 x 50 x 127 Most common causes for a surface with a lead Coaxiality of tool and workpiece axis Can create a lead on the Coaxiality as small as Most common causes for surface possible a surface with a lead Tab. 17 Machining guidelines for the ground surface of the shaft I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 325 X E D N I

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Seals for Rotary Applications PARAMETERS FOR HARD-TURNED SHAFTS Feed Cutting speed Radius Depth of cut Material on the insert Hardness VALUES 0.03 … 0.10 mm 100 … 300 m/min 0.4 … 1.2 mm Max. 0.15 mm CBN (Cubic Boron Nitride) 55 … 62 HRC Requirements for the machined surface Ra = 0.1 … 0.8 µm, Rz = 1 … 4 µm, Rmax < 8 µm No damage due to chips or blunt tools permitted Typical empirical values for hard-turned shafts; depending on lathe, shaft material and cutting tool, the optimal parameters must be verified at the customer’s site Tab. 18 Machining parameters for hard-turned shafts 326

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8. Design notes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I TEST METHOD WITH THE FOLLOWING PARAMETERS R O F S L A E S Y R A T O R S N O I T A C I L P P A TEST PROCEDURE Shaft position: Align horizontally 1. lightly wet shaft with oil Lubricant: Wet shaft with thin oil (e. g. Pentosine CHF 11S) Thread: Fishing line 0.08 mm 2. hang up thread with weight 3. turn shaft a few revolutions Wrap angle of the thread: > 180° , < 270° Weight: Speed: 30 g for shaft Ø < 100 mm 50 g for shaft Ø > 100 mm Approx. 20 rp m with change of direction of rotation 4. draw an axial line on the underside of the shaft with a pencil 5. allow shaft to rotate approx. 20 revolutions 6. examine axial pencil line for wiping effects 7. repeat procedure with reverse direction of rotation 8. no wiping effect can be detected when there are no leads Shaft with right hand thread Shaft with left hand thread Pencil mark on the shaft surface is wiped off when the thread is moved The direction of movement of the thread corresponds to the direction of oil flow Fig. 150 Detection of lead on the shaft (lead-test according to the thread method) R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 327 X E D N I

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Seals for Rotary Applications bearing clearance must be kept as small as possible. The seal must be arranged in the immediate vicinity of the bearing. Permissible values for the radial runout are shown in → Fig. 152. INSTALLATION CHAMFER ON SHAFT The recommended angle for the installa- tion chamfer on the shaft is 15° to 25° (→ Fig. 153). The diameter d3 of the chamfer, according to → Fig. 153, can be found in → Tab. 19. DAMAGE TO THE SHAFT Scratches, pressure marks, rust and other damage in the area of the seal running surface lead to leakage. Therefore, utmost care should be taken to protect the shaft from manufacturing to final assembly by using protective covers and special trans- port devices. COAXIALITY Too great a deviation in center between the shaft and the receiving bore, i.e. too great a deviation in coaxiality, leads to uneven distribution of the contact pres- sure over the circumference of the shaft and thus to greater wear of the sealing lip on one side. The local loss of contact pres- sure can impair the sealing function. For permissible values, see → Fig. 151. RUNOUT DEVIATION Concentricity deviation or dynamic eccen- tricity should be avoided as far as possible. At high speeds, there is a risk that the sealing lip will no longer be able to follow the shaft due to its inertia. The resulting increase in the sealing gap between the sealing edge and the shaft leads to leak- age above a certain size. Therefore, the A g n i s u o H Ø Ø X,X A t f a h S Ø n o i t ] m m [ i a v e d y t i l i a x a o C 0.4 0.3 0.2 0.1 0 0 40 80 120 160 200 240 280 ... 500 Shaft diameter [mm] Fig. 151 Max. deviation of coaxiality as a function of shaft diameter 328

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F i g . 1 5 2 M a x . r u n o u t d e v i a t i o n s o f t h e s h a f t a s a f u n c t i o n o f s p e e d 3 2 9 Ø Shaft X X , A Ø Housing A Concentricity deviation [mm] . . . . 0 4 0 1 . 0 . 2 0 . 3 0 0 2 0 0 0 4 0 0 0 6 0 0 0 8 0 0 0 N B R - F K M S h a f t s p e e d [ r p m ] INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS 8 . D e s i g n n o t e s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Seals for Rotary Applications RZ = 1 to 5 µm lead-free ground R h11 dN d3 R: for BA 0.6 mm for BASL 1.0 mm Fig. 153 Radius and installation chamfer of the shaft dN [mm] Up to 10 10 … 20 20 … 30 30 … 40 40 … 50 50 … 70 70 … 90 90 … 140 140 … 250 > 250 Tab. 19 Diameter for the shaft installation chamfer 330 Edge rounded and polished 15‒25° Map-Marker-Exclamation In case of assembly direction with dust lip ahead against radius: consulta- tion with technical contact person to define remedial measures against folding over of the dust lip d3 [mm] dN – 1.5 dN – 2.0 dN – 2.5 dN – 3.0 dN – 3.5 dN – 4.0 dN – 4.5 dN – 5.0 dN – 7.0 dN – 11.0

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8. Design notes t2 t1 Chamfer 15‒20° I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Bore d2 H8 R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P 8.2 DESIGN OF THE HOUSING ROUGHNESS Permissible values: For BA and BASL designs Rmax < 25 µm Ra Rz = 1.6 ... 6.3 µm = 10 ... 25 µm For B1 and B1SL as well as B2 and B2SL designs Rmax < 16 µm Ra Rz = 0.8 ... 3.2 µm = 6.3 ... 16 µm TOLERANCE ISO H8 Fig. 154 Depth and chamfer of the housing THERMAL EXPANSION When heated, the overlap between the housing and the seal is reduced, especially in the case of housings made of light metal, plastic or similar. DEPTH The bore depth and the chamfer must be designed in such a way that in the assem- bly end position, the cylindrical part of the seat diameter of the seal is completely mounted in the cylindrical part of the bore. Otherwise, there is a risk that the seal will move after assembly. This can result in a skewed position or complete dislocation of the seal out of the bore.   CHAMFER y recommended angle value: 15° ... 20° (→ Fig. 154) y the transitions must be made without burrs y chamfer length according to DIN 3760 For this reason, the use of the BA design is recommended in these cases, as it can better follow the expansion of the housing due to the larger overlap and the higher thermal expansion coefficient. Map-Marker-Exclamation Avoid skewing and dislocation Adhesive part width [mm] 7 8 10 12 15 20 t1min (0.85 x b) t2min (b + 0.3) [mm] 5.95 6.80 8.50 10.30 12.75 17.00 [mm] 7.30 8.30 10.30 12.30 15.30 20.30 Tab. 20 Minimum values for the depth of the housing S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 331 X E D N I

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Seals for Rotary Applications SPLIT HOUSINGS The necessary compensation of a possible offset at the partial joint can be achieved most reliably with the BA design. STIFFNESS When installing Simmerring® in thin-walled locating bores or locating bores with low elasticity or strength, there is a risk that the housing will be deformed or cracked. Therefore, the BA design should be used and, if necessary, the tolerance of the bore should be changed to F8. RETAINING CLAW If, for various reasons, the holding force of the Simmerring® in the bore is not suffi- cient, it is recommended to fit a small groove (retaining claw) to the housing bore. This reliably prevents a possible spring-back of the seal and can significantly increase the squeezing force. 20° ±2° 0.3 +0.1 0.8 Fig. 155 Retaining claw 332

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9. MODIFIED CATALOG SEALS 9. Modiﬁed catalog seals Simmerring® with a shortened dust lip without overlap to the shaft (→ Fig. 157). Small clearance between the dust lip and the rotating shaft does not generate any additional friction. At the same time, the dust lip offers a certain degree of protec- tion against larger contamination parti- cles, despite its lack of contact with the shaft. FST Sales Sheet Modified Catalog Program Fig. 156 BAUMSL with a vented dust lip Fig. 157 BAUMSL with a shortened dust lip Simmerring® features – ﬂexible & appli- cation-oriented The Freudenberg Sealing Technologies (FST) catalog for Simmerring® covers a wide range of sealing applications, includ- ing a variety of different dimensions, de- signs and materials. Nevertheless, specif- ic operating conditions may require a seal that is tailored to the application in order to ensure a proper sealing function or to increase the service life of the sealing point. For this reason, we make it possible to optimize existing Simmerring® from our extensive catalog range by making modifications to them. MODIFICATION OF THE DUST LIP AT HIGH CIRCUMFERENTIAL SPEEDS Simmerring® from the catalog equipped with a dust lip in contact with the shaft offer optimal protection of the sealing lip against light external contamination by dust or splash water. At circumferential speeds of the shaft > 8 m/s, suction of the sealing lip and dust lip on the shaft sur- face occurs, generating increased friction, thermal stress and premature wear. Therefore, depending on the operating conditions, we recommend using seals with a dust lip in contact with the shaft up to a maximum circumferential speed of the shaft of 8 m/s. If, in an application, the circumferential speed of the shaft is > 8 m/s and an exter- nal dirt exposure requires a design with a dust lip, a modified component with a vented dust lip can offset the suction of the lips towards the shaft and at the same time provide protection against external contamination (→ Fig. 156). The circumferential speed of the shaft > 15 m/s requires a modified catalog I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 333 X E D N I

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Seals for Rotary Applications SIMMERRING® WITH A MODIFIED SPRING If an application generates an increased circumferential speed of the shaft, the elastomer material of the sealing edge and the lubricant may be subjected to high thermal stress, especially if the lu- bricant supply to the sealing point is in- sufficient. Depending on the technical conditions inside the unit, the friction and thus the temperature development can be significantly reduced by reducing the spring force resulting in a lower total radial force. This leads to a longer service life and energy efficient improvement in the system. If there are high vibrations or there is a high radial runout of the shaft during operation, the spring force and therefore also the total radial force generated can be increased in applications with limited circumferential speed (→ Fig. 158). This improves the ability of the sealing lip to follow radial motions of the shaft. If a radial shaft seal is subject to ingress of water or corrosive media corrosion, es- pecially of the spring, may occur if it is not made of a corrosion-resistant material (stainless steel). By replacing the stand- ard spring with a stainless steel spring, the catalog Simmerring® can be optimized to meet the specific requirements of the application. COMBINATION WITH A NON-WOVEN EXCLUDER LIP FOR INCREASED PROTECTION AGAINST EXTERNAL CONTAMINATION If there is a high contamination environ- ment that exceeds the application limits of a conventional Simmerring® with a dust lip, a modified catalog component combined with a non-woven excluder lip from Freudenberg can be used (→ Fig. 159). The non-woven materials being used can hold back dry dust and/or damp dirt. At the same time, however, the open-pored structure of the material pre- vents the non-woven excluder lip and the seal edge from being sucked on the shaft at high peripheral speed. The non-woven excluder lips also generate low friction with the shaft. The installation height is only slightly affected by the use of a non-woven excluder lip. This means that smaller heights can be achieved than with special designs or in conjunction with ad- ditional sealing elements. Fig. 158 Simmerring® with a rein- forced spring Fig. 159 BAUMSL combined with a non-woven excluder lip – for external loading of dirt Fig. 160 BAUM with an eCON combined electrically con- ductive non-woven disc 334

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9. Modified catalog seals COMBINATION WITH AN ECON ELEC- TRICALLY CONDUCTIVE NON-WOVEN DISC AS AN EQUIPOTENTIAL BONDING ELEMENT FOR PROTECTING BEARINGS Potential build-up between the shaft and the housing during operation can lead to voltage flashovers that can cause dam- age to the surface of bearing shells. An electrically conductive non-woven disc provides equipotential bonding between the housing and the shaft and helps to increase the service life of the bearing and the overall system in critical applica- tions (→ Fig. 160). The installation height is only slightly affected by the use of the eCON. This means that significantly smaller installation heights can be achieved than with conventional equipo- tential bonding elements. COMBINATION WITH A PTFE DISC FOR EXTERNAL CONTACT WITH AGGRESSIVE MEDIA Contact with aggressive media can lead to chemical attack of the elastomer ma- terial, especially if the systems need to be cleaned regularly. A PTFE disc fitted onto the air side can protect the seal from con- tact with the aggressive cleaning media (CIP/SIP) (→ Fig. 161). Solutions with food-grade PTFE materials are also avail- able for food & beverage applications. The installation height is only slightly affected by the use of a PTFE excluder lip. This means that smaller heights can be achieved compared to conventional solu- tions in conjunction with additional seal- ing elements. PRE-GREASED DUST LIP Simmerring® with a dust lip which has an overlap to the shaft must be lubricated by using a grease pack that is applied be- fore assembly (→ Fig. 162). The amount of grease used is extremely important. Too little grease leads to lubrication of the dust lip for a limited time only. If too much grease is applied before assembly, the grease can be forced out of the grease chamber between the shaft and the dust lip when the temperature increases. The escaping medium can then be interpret- ed by the end customer as oil leakage. This so-called false leakage can be avoid- ed by greasing the Simmerring® properly. Fig. 161 Simmerring® combined Fig. 162 BAUMSL with a greased with a PTFE disc dust lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 335 X E D N I

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Seals for Rotary Applications pressure of a maximum of 1–2 bar. This depends on the remaining operating con- ditions (temperature, speed, etc.), among other factors. The design of the back-up must be adapt- ed exactly to the sealing lip profile. For this purpose, you can request the corre- sponding drawing of the backup ring from us by simply providing us with the exact article designation or article number. SIMMERRING® WITH FKM PLUS COATING When sealing synthetic lubricants, such as modern polyglycol oils, partial defi- cient lubrication can occur in the contact zone between the sealing lip and the shaft in some applications due to the poor wetting properties of the lubricant. This can result in increased seal lip wear and shaft run-in. The 75 FKM 585 plus coating is an inno- vative technology for modifying the seal- ing lip surface. It improves the wetting behavior of the sealing lip of Simmerring® made of 75 FKM 585 for use with syn- thetic oils (→ Fig. 163). SIMMERRING® IN COMBINATION WITH BACK-UP RINGS Some applications require Simmerring® that can withstand pressure loads, such as the standard BABSL design. If no Simmerring® BABSL is available in desired sizes or if the pressure load is only applied for a short time, a BAUM profile without a dust lip that is supported by a back-up ring can be used under certain operating conditions (→ Fig. 164). As a rule, back-up rings can be used up to a Fig. 163 Simmerring® with FKM Fig. 164 Simmerring® with back- plus coating up ring 336

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9. Modified catalog seals TECHNICAL SPECIFICATION MODIFICATION BENEFITS Increased circum ferential speed Special spring with reduced spring force Reduces friction and temperature inside the system Vibrations and shaft run-out Special spring with increased spring force Increases the robustness of the sealing system Corrosion Stainless steel spring Ensures the functionality of the spring Increased dirt impact due to dry dust or damp dirt Combination with a non-woven disc in application-specific material Different electric potential between the shaft and the housing Combination with an eCON electrically conductive non- woven disc Increased external c ontam- ination due to aggressive media (e.g. cleaning media) Combined PTFE sealing element Pre-greasing Grease pack between the sealing lip and the dust lip Use of synthetic lubricants with insufficient wetting properties of the sealing lip FKM plus coating Tab. 21 Modification of Simmerring® at a glance Additional protection against dirt Wear resistant and low friction Space-saving solution Reliable electric discharge between the housing and the rotating shaft Low friction Space saving solution Very high protective function Very high chemical resistance Space-saving solution Application according to hygienic design, free from dead space Food grade PTFE sealing element Know-how regarding compatibility of elastomer materials and lubricants Appropriate application of grease to prevent causes of defects Service support Improvement of contact lubrication Reduction of friction Reduced sealing lip and shaft wear Increased service life I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 337 X E D N I

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Seals for Rotary Applications 10. PRESELECTION OF SEALS FOR ROTARY APPLICATIONS 10.1 PRESELECTION SIMMERRING® The selection of a suitable Simmerring® can be made in two steps. If the operat- ing conditions are known, the parameters of pressure, temperature, speed, medium, contamination and required protective function can be used to make a sugges- tion regarding the Simmerring® design and material. Based on this, a suitable article can be determined from the cata- log range by additionally specifying the dimensions. Simmerring® selection No Simmerring® design and material known? Yes Selection via application data* Pressure Temperature Speed Medium Dirt Protection Result: Simmerring® design and material Selection with known Simmerring® design** Shaft Ø Housing Ø Result: y Simmerring® available in catalog range y if not: component must be requested Wide Material Design Dust lip * Selection via Simmerring® selector or via selection diagram page 146 and page 148. Mutual influence of selection parameters must be taken into account ** Selection via Simmerring® Selector or via FST product catalog Fig. 165 Flow diagram for the procedure for preselecting Simmerring® Simmerring® Selector 338

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10. Preselection of seals for rotary applications The resulting product selection does not constitute a recommendation and does not replace specific advice for the intended application in individual cases. Freudenberg Sealing Technologies therefore accepts no liability whatsoever for the suitability of the product selection determined with regard to the specific application intend- ed by the customer. In this context, FST points out in particular that the sealing effect is not provided by the component itself alone, but that various influencing factors in the tribological system (includ- ing temperature curves, pressure curve, shaft machining, tolerances, interaction with media/additives) must also be taken into account. These and other factors have an influence on the sealing effect of the product, so that the seal must be tested and released by the user in the application. Freudenberg Sealing Technologies recommends the involvement of a sealing specialist, espe- cially for critical applications. All offers are subject to change and are not binding. FST expressly reserves the right to change or delete the product range or the information presented on the website in whole or in part at any time without special notice, or to interrupt or completely discontinue the availability of the information. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 339 X E D N I

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Seals for Rotary Applications PRESELECTION OF SIMMERRING® The resulting product selection does not represent a recommendation and does not replace specific advice for the intended application in individual cases. TEMPERATURE* * Sealing lip temperature If not known: Use Simmerring® selector. (Regarding temperature range 0 °C to ‒40 °C see “5.2 Special materials for Simmerring®,” page 304 Max. perm. temperature dependent on medium → page 311 ‒40 °C … +100 °C* ‒25 °C … +160 °C* For components BAUM(SL), B1UM(SL), BAFUD(SL), B1FUD(SL) the material selection is additionally carried out via Fig. 136, page 310 ≤ 0.5 bar BAUM BAUMSL MSS1 PRESSURE ≥ 0.5 ≤ 1.5 bar p = pMedium – poutside … BA… with back-up ring poutside pmedium > 0.5 … 10 bar ] s / m [ 40 30 20 10 5 0 Shaft speed [rpm] 30 000 15 000 10 000 9000 8000 7000 6000 5000 4500 4000 FKM 3500 3000 2500 2000 1500 NBR 1000 Grease 500 200 ... 500 0 25 50 100 150 Shaft diameter [mm] l y p p u s t n a c i r b u l t n e c i f f u s d n a l i i o e n g n e i p i l g n i l a e s e h t o t 0 2 E A S g n i l l a e s r o f y p p a s e u a v e d u G i l 0 1 3 e g a P → 6 3 1 . g F i pv = p [bar] x v [m/s] Dependence of permissible pressure on speed for type BABSL or PPS → page 317 for BAUM(SL), B1UM(SL), BAFUD(SL) designs, B1FUD(SL), B2(SL) → page 314, Tab. 16 SPEED 340

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10. Preselection of seals for rotary applications Profile BAUM NBR FKM I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H ≤ 0.2 bar MSS7 Cassette BA (B1)…FUD…SL ≤ 0.2 bar PPS: pvmax = 40 BABSL: pvmax = 12 Profile BAUM BABSL BABSL ] r a b [ e r u s s e r P 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0 7 1 3 e g a P → 4 4 1 . g F i Ø 1 6 0 m Ø 8 0 m m m Wellen Ø 40 m m Ø 20 mm 0 1000 2000 3000 4000 5000 6000 7000 Shaft speed [rpm] PPS PPS Ø 40 mm Ø 60 mm Ø 80 mm 0 1000 2000 3000 4000 5000 6000 7000 Shaft speed [rpm] ] r a b [ e r u s s e r P 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 7 1 3 e g a P → 5 4 1 . g F i Circumferential speed v = π • d [mm] • n [1/min] [ ]mm 60 • 1000 ––– m [ ]s ––– min R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 341 X E D N I

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Seals for Rotary Applications PRESELECTION OF SIMMERRING® The resulting product selection does not represent a recommendation and does not replace specific advice for the intended application in individual cases. MEDIUM Mineral oil Note: Shown designs for material selection are only examples. Other designs are also available. PAO oil PAG oil Biodegradable oils Grease Water Aggressive media Dry run 72 NBR 902 Tension spring and metal case Catalog part NOT made of stainless steel (if necessary, modified catalog part with stainless steel tension spring or customer-specific component) PTFE B2PT from catalog in stainless steel design but without conveying helix (no pumping effect of the sealing edge) 72 NBR 902 75 FKM 585 75 FKM 170055 max. +80 °C 72 NBR 902 dashed line from diagram 75 FKM 585 75 FKM Plus 75 FKM 170055 FKM variant on request Not valid for all biodegradable oils. Storage test required DIRT Inside Outside Dust 2 Simmerrings® in series MSS1 Splash water Fluid flooded Mud PROTECTION Cleaning media (CIP/SIP) from the outside BAUMSL + PTFE disc 342 Electr. current continuity (bearing protection)

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10. Preselection of seals for rotary applications Shaft speed [rpm] 30 000 15 000 10 000 9000 8000 7000 6000 5000 4500 4000 FKM 3500 3000 2500 2000 1500 NBR 1000 Grease 500 200 ... 500 0 25 50 100 150 Shaft diameter [mm] Circumferential speed Guide values apply for sealing engine oil SAE 20 and sufficient lubricant supply to the sealing edge. If operating points are located in the dark gray range, special designs are required. Limit: see diagramm short- timely limit: 15 m/s Limit: 8 m/s ] s / m [ d e e p s l a i t f n e r e m u c r i C 40 30 20 10 5 0 no dust lip or shortened dust lip without contact to shaft vented dust lip with contact to shaft standard dust lip with contact to shaft Depending on circumferential speed v = BAUMSL BAUMSL SL vented BAUMSL BAUMSL BAUM SL shortened + non-woven + non-woven π • d [mm] • n [1/min] [ ]mm 60 • 1000 ––– m [ ]s ––– min BAUMSL BAUMSLX6 MSS7 BAUMSL + non-woven Cassette Combi Seal Good protection against dust and mud 2 x BAUM Back-to-Back Tension spring and metal case made of stainless steel may be necessary on the water side I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P BAUM eCON 343 X E D N I

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Seals for Rotary Applications 10.2 PRESELECTION OF SIMMERRING® CASSETTE AND COMBI SEALS SELECTION CRITERIA FOR CASSETTE AND COMBI SEALS The family of cassette and combi seals includes several products covering a wide range of operating conditions and envi- ronments. → Fig. 166 does not compare the perfor- mance of the products, but serves to pre- select the products depending on the area of application (circumferential speed and degree of contamination of the envi- ronment). The technicians at Freudenberg Sealing Technologies will be happy to assist you in selecting the right product for the re- spective application. THE MOST IMPORTANT ASPECTS AT A GLANCE y Temperature y Circumferential speed y Axial movement y Pressure y Eccentricity (static and dynamic) y Medium type y Direction of rotation (CW, CCW, both CW/CCW) y Rotating element (shaft or bore) y Installation procedure y Pollution level of the environment Special operating conditions must be agreed with Freudenberg Sealing Tech- nologies. h g H i i m u d e M w o L CASCO Cassette HS Combi Combi SF5 Combi SF6 Combi SF8 Combi SF19 Combi SF21 Combi SF22 Cassette Type 1 Cassette Type 2 Cassette Type 3 Cassette Type 4 Very low Low Medium High Very high Pollution level of the environment ) s / m ( d e e p s l a i t f n e r e m u c r i C Fig. 166 Preselection of Simmerring® cassette seal and Simmerring® combi seal 344

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3 4 5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING 1 0 . P r e s e l e c t i o n o f s e a l s f o r r o t a r y a p p l i c a t i o n s INTRODUCTION & SERVICES

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Seals for Rotary Applications 10.3 PRODUCT FINDER DIN Design A AS SIMMERRING® BA… BAF… BA…SL Material NBR FKM NBR NBR FKM [C°] [m/s] Temperature Circumferential speed +160 ‒25 38 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 14 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 14 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 8 +160 ‒25 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 Pressure Size range Special requirements Dirt accumulation Medium Max. [MPa] Please refer to the diagram on page 116! 0.05 0.02 0.05 [mm] 3 … 1,200 6 … 185 6 … 820 High roughness of the housing High thermal expansion of the housing Use in split housings Tightness against pressure Very tight hold of the seal in the housing High stiffness of the seal, rough assembly Normal dirt accumulation outside Moderate to medium dirt accumulation outside High dirt accumulation outside Foreign particles inside Mineral oils < +100 °C Synthetic oils < +80 °C Mineral oils > +100 °C Synthetic oils > +80 °C Greases Aggressive media Dry run C C C C C D D D D D B B D D B D D C C C C C D D D D D B C B B B D D C C C C C D D D D D B B D D B D D C C C C C D B D D D B B D D B D D C C C C C D B D D D B C B B B D D Verify media compatibility depending on application conditions. C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable 346

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10. Preselection of seals for rotary applications AS A B SIMMERRING® BAF…SL PSS BABSL PPS BAHD B1… B1F… NBR FKM NBR FKM FKM NBR FKM NBR NBR 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +160 ‒25 38 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 0.02 0,03 (pressure peaks 0.05 MPa) +100 °C ‒ 40 10 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 1 +160 ‒25 10 +160 ‒25 15 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒30 2 m/s +160 ‒25 2 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 14 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 14 1 (pressure peaks 2.5 MPa) 10 (pressure peaks 15 MPa) 0.05 0.02 15 … 100 Upon request 8 … 479 12 … 110 28 … 175 6 … 960 8 … 190 C C C C C D B D D D B B D D B D D C C C C C D B D D B B C B B B D D C C C C C D B D D D C C D D C D D C C C C C D B D D D C C B B C D D C C C C C D B D D D C C B B C D D C C C B C D D D D D B C D D D D D C C C B C D D D D D C C B B D D D D D D D B D D D D D C C D D C D D D D D D B D D D D D C C D D C D D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 347 X E D N I

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Seals for Rotary Applications DIN Design BS C CS SIMMERRING® B1…SL B1F…SL B2… B2F… B2…SL Material NBR NBR NBR NBR NBR [C°] [m/s] Temperature Circumferential speed 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 14 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 14 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 8 Pressure Size range Special requirements Dirt accumulation Medium Max. [MPa] Please refer to the diagram on page 310! 0.05 0.02 0.05 0.02 0.05 [mm] 13 … 630 13 … 115 15 … 710 25 … 710 25 … 560 High roughness of the housing High thermal expansion of the housing Use in split housings Tightness against pressure Very tight hold of the seal in the housing High stiffness of the seal, rough assembly Normal dirt accumulation outside Moderate to medium dirt accumulation outside High dirt accumulation outside Foreign particles inside Mineral oils < +100 °C Synthetic oils < +80 °C Mineral oils > +100 °C Synthetic oils > +80 °C Greases Aggressive media Dry run D D D D B D B D D D C C D D C D D D D D D B D B D D D C C D D C D D D D D D B B D D D D C C D D C D D D D D D B B D D D D C C D D C D D D D D D B B B D D D C C D D C D D Verify media compatibility depending on application conditions. C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable 348

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10. Preselection of seals for rotary applications CS A B SIMMERRING® B2F…SL B2PT BLUESEAL BAPT/PTS BAOF B1OF MSS1 NBR PTFE PTFE PTFE NBR NBR NBR-FKM FKM-FKM 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +200 ‒80 30 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +200 ‒80 40 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 30 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 6 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 6 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒ 40 6 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +160 ‒25 6 0.02 1 0.03 0.02 – – 0.05 0.05 35 … 170 8 … 175 Upon request Upon request 8 … 230 12 … 320 20 … 145 D D D D B B B D D D C C D D C D D D D D D B C D D D D C C D D C B D D D D D C D D D D D C C C C C B B C C C C B D B C D D C C C C C C B C C C C D D C C D D C C D D B D D D D D D B D C C D D C C D D B D D C C C C D D B C D B B B B B D D D C C C C D D B C D B B C B B D D D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 349 X E D N I

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Seals for Rotary Applications DIN Design MSS7 HTS II 9539 TYP 9444 G61 RCD PTFE SHAFT SEALS Material NBR-NBR PTFE PTFE PTFE PTFE [C°] [m/s] Temperature Circumferential speed 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 5 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +200 200 100 50 +200 °C 0 ‒20 ‒80 ‒50 ‒100 50 40 30 20 10 5 0 4 m/s 25 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +200 ‒80 25 m/s +200 ‒80 5‒25 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 Pressure Size range Special requirements Dirt accumulation Medium Max. [MPa] 0.05 0.6 0.8 0.8 0 [mm] 35 … 150 10 … 250 10 … 250 35 … 250 100 … 800 High roughness of the housing High thermal expansion of the housing Use in split housings Tightness against pressure Very tight hold of the seal in the housing High stiffness of the seal, rough assembly Normal dirt accumulation outside Moderate to medium dirt accumulation outside High dirt accumulation outside Foreign particles inside Mineral oils < +100 °C Synthetic oils < +80 °C Mineral oils > +100 °C Synthetic oils > +80 °C Greases Aggressive media Dry run C C C C C D D C B D C C D D C D D D B D C B D B D B B B D D B D B D B B D B D B C D D D B C** C** C** C** D D B B B B B B B D D B B B B B B B D D B B B B B B C D D B B B B D B C Verify media compatibility depending on application conditions. C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable 350

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10. Preselection of seals for rotary applications MERKEL RADIAMATIC® R35 R55 RHS51 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A NBR HNBR FKM NBR HNBR NBR HNBR FKM +100 ‒30 20 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 +120 ‒20 25 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒10 25 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒30 5 200 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒20 5 +100 ‒30 25 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 +120 ‒20 30 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒10 35 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 0.05 0.05 0.02 100 … 2,500 100 … 2,500 200 … 1,800 D B D C D B D C D B D C D B D C D B D C Cover Plate Cover Plate Cover Plate Cover Plate Cover Plate C B C** D D B B D D C* C* D C B C** D D B B B B C* C* D C B C** D D B B B B C* C* D C B C** D D B B D D C* C* D C B C** D D B B B B C* C* D D B D C C C B D B D C C C B D B D C C C B C** C** C** D D B B B B D C* D D D B B B B D C* D D D B B B B D C* D R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 351 X E D N I

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Seals for Rotary Applications DIN Design SEVENTOMATIC® TBM SEALS RPM41 S71 TBM21/TBM27R TBM8101 Material NBR HNBR NBR HNBR PU [C°] [m/s] Temperature Circumferential speed +100 ‒30 15 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒20 3 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒30 2 m/s 200 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒20 2 m/s 200 100 50 0 ‒50 +80 °C ‒25 (Wasser max. +60 °C) 50 40 30 20 10 5 0 1 m/s Pressure Size range Special requirements Dirt accumulation Medium Max. [MPa] Ø D < 700 mm: 0.05 Ø D > 700 mm: 0.03 0.05 0.5 2 [mm] 200 … 1,100 > 1,000 > 1,500 100 … 2,000 High roughness of the housing High thermal expansion of the housing Use in split housings Tightness against pressure Very tight hold of the seal in the housing High stiffness of the seal, rough assembly Normal dirt accumulation outside Moderate to medium dirt accumulation outside High dirt accumulation outside Foreign particles inside Mineral oils < +100 °C Synthetic oils < +80 °C Mineral oils > +100 °C Synthetic oils > +80 °C Greases Aggressive media Dry run D B D C C C B C** D D C B D D B C* D D B D C D B D B D B D B D B D B Cover Plate Cover Plate Cover Plate Cover Plate C B C** D D B C* B B B C* D B B B B D B B D D B C* D B B B B D B B B B B C* D B B B B D C (max. +80 °C) B D D B C* D Verify media compatibility depending on application conditions. C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable 352

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10. Preselection of seals for rotary applications WATER GUARDS CASSETTE SEAL ENVIROMATIC EA WA8074 V-RING WA-A TYP 1 NBR +100 ‒30 20 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 HNBR 200 100 +120 ‒20 20 50 0 ‒50 ‒100 50 40 30 20 10 5 0 PU NBR FKM NBR 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +110 ‒30 6 +100 ‒30 20 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒10 20 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 7 FKM 200 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒25 9 0.03 > 100 B B C D B B C D Fixing System Fixing System C B B B D B B D D B C* C C B B B D B B B B B C* C 0.05 0.03 0.05 20 … 2,200 3 … 2,000 25 … 240 1) B B C D C C B B B D B B B B B C* D B B C D C C B B C D B B D D B C* C B B C D C C B B C D B B B B B C* C C C C C B B B D D D C B D D B D D C C C C B B B D D D B B B B B D D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 1) Shaft dimensions outside this range must be evaluated by a feasibility study with an FST technician 353 X E D N I

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Seals for Rotary Applications DIN Design Material Temperature Circumferential speed Pressure Size range Special requirements Dirt accumulation Medium [C°] [m/s] Max. [MPa] [mm] High roughness of the housing High thermal expansion of the housing Use in split housings Tightness against pressure Very tight hold of the seal in the housing High stiffness of the seal, rough assembly Normal dirt accumulation outside Moderate to medium dirt accumulation outside High dirt accumulation outside Foreign particles inside Mineral oils < +100 °C Synthetic oils < +80 °C Mineral oils > +100 °C Synthetic oils > +80 °C Greases Aggressive media Dry run CASSETTE SEAL TYP 2 TYP 3 NBR 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 5 FKM 200 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒25 7 NBR 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 4 FKM 200 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒25 6 0.05 0.05 25 … 240 1) 25 … 240 1) C C C C B B C B D D C B D D B D D C C C C B B C B D D B B B B B D D C C C C B B C C B D C B D D B D D C C C C B B C C B D B B B B B D D Verify media compatibility depending on application conditions. C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable 354

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10. Preselection of seals for rotary applications CASSETTE SEAL COMBI SEALS TYP 4 HS COMBI SEAL SF5 NBR FKM FKM NBR + AU FKM + AU NBR + AU FKM + AU 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 4 200 200 100 +120 100 +120 50 0 ‒50 ‒100 50 40 30 20 10 5 0 ‒25 6 ‒25 15 50 0 ‒50 ‒100 50 40 30 20 10 5 0 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 0.05 0.05 0.03 0.03 35 … 240 1) 25 … 100 1) 25 … 240 1) 25 … 175 1) C C C C B B C C B D C B D D B D D C C C C B B C C B D B B B B B D D C C C D B B B C D D B B B B B D D D D D C B B B C D D C B D D B D D D D D C B B B C D D B B C C B D D D D D C B B B C D D C B D D B D D D D D C B B B C D D B B C C B D D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 1) Shaft dimensions outside this range must be evaluated by a feasibility study with an FST technician 355 X E D N I

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Seals for Rotary Applications DIN Design COMBI SEALS SF6 SF8 Material NBR + AU FKM + AU NBR + AU FKM + AU [C°] [m/s] Temperature Circumferential speed Pressure Size range Special requirements Dirt accumulation Medium Max. [MPa] [mm] High roughness of the housing High thermal expansion of the housing Use in split housings Tightness against pressure Very tight hold of the seal in the housing High stiffness of the seal, rough assembly Normal dirt accumulation outside Moderate to medium dirt accumulation outside High dirt accumulation outside Foreign particles inside Mineral oils < +100 °C Synthetic oils < +80 °C Mineral oils > +100 °C Synthetic oils > +80 °C Greases Aggressive media Dry run 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 0.03 0.03 25 … 130 1) 25 … 130 1) D D D C B B C B D D C B D D B D D D D D C B B C B D D B B C C B D D C D D C B B C B C D C B D D B D D C D D C B B C B C D B B C C B D D Verify media compatibility depending on application conditions. C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable 356

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10. Preselection of seals for rotary applications SF19 COMBI SEALS SF21 SF22 NBR + AU FKM + AU NBR + AU FKM + AU NBR + AU FKM + AU 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 °C ‒ 40 8 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒25 8 0.03 0.03 0.03 25 … 130 1) 25 … 130 1) 25 … 130 1) C D D C B B C C B D C B D D B D D C D D C B B C C B D B B C C B D D C D D C B B C C B D C B D D B D D C D D C B B C C B D B B C C B D D C D D C B B C C B D C B D D B D D C D D C B B C C B D B B C C B D D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 1) Shaft dimensions outside this range must be evaluated by a feasibility study with an FST technician 357 X E D N I

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Seals for Rotary Applications 11. HANDLING AND INSTALLATION OF RADIAL SHAFT SEALS During handling and installation, it is im- portant to avoid contact of the radial shaft seal, especially in the area of the sealing lip, with sharp edges and any con- tamination. Experience shows that approx. 30% of all early failures are due to improper in- stallation of the radial shaft seal or faulty installation aids. The list of possible causes of faults in the handling and installation of radial shaft seals by the user is intended to help iden- tify them and take corrective measures for the following main points. Error han- dling see → page 391. 11.1 GOODS RECEIPT OF COMPONENTS y storage y transportation y intermediate storage at the assembly station y preparation for assembly y assembly station y counter point of the seal (shaft) y housing bore y handling of hydraulic power units See also → chapter “Materials and Process engineering – 11. Proper storage“, page 178. HANDLING GUIDELINES FOR STORAGE (DIN 7716 ISO 2230) Conditions of storage: y temperatures: ‒10 °C to max. +25 °C y relative humidity of < 65 y in adequate packaging y no direct influence of light y no solar radiation y storage rooms must not contain any ozone-generating equipment 11.2 HANDLING The large number of possible interference points requires numerous indications that seem trivial at first glance. In practical handling, however, the neces- sary care is nevertheless often neglected. A few examples from the extensive num- ber of notes: y check for damaged transport packag- ing or individual packaging y if possible, leave seals in their pack- aging until assembly y do not leave seals loose y protect seals from dust, dirt, sunlight and ozone y keep greased seals in suitable con- tainers or under cover y use only clean grease or oil for initial lubrication y use only clean and suitable grease for dust lip lubrication (e.g. no greases with solid lubricants) y avoid excessive greasing (prevention of apparent leakage) y do not bring the sealing lip and in par- ticular the sealing edge into contact with sharp edges or damaged instal- lation tools y avoid metal chips or other particles y sharp-edged chamfers at shaft transi- tions and housing bore are not permis- sible y damage and corrosion of running sur- face on shaft and locating bore are not permissible y pay attention to low coaxiality devi- ation of bore and shaft Map-marker-edit Approx. 30% of all early failures are due to installation errors 358

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11. Handling and installation of radial shaft seals y if the unit with the radial shaft seal installed is to be painted or otherwise coated, the seal and also the contact area of the shaft must be protected against paint or spray mist (→ Fig. 167) Correct amount of grease approx. 40% Grease quantity too high → overgreasing Fig. 168 Illustration of correctly greased component and component with overgreasing Fig. 167 Protection of radial shaft seal and shaft during painting 11.3 GREASING OF SIMMERRING® The Simmerring® or the associated run- ning point of the shaft must be initially greased before assembly to ensure lubri- cation of the sealing edge for the first revolutions of the shaft until lubrication by the fluid to be sealed sets in. Fig. 169 A Simmerring® automatically greased at FST 11.4 PACKAGING OF SIMMERRING® Before installation, components with a dust lip must be lubricated with a suitable grease between the dust lip and the seal- ing edge to approx. 40% of the enclosed volume. The lubrication of the dust lip re- duces friction and wear (→ “Services – Lube & Seal”, page 12). Industry packaging Depending on the design and size, Sim- merring® from the catalog range are of- fered in pack sizes (cardboard boxes) with a quantity of up to several hundred parts. The outer packaging has an adhesive label with the component- specific data. Excessive lubrication of the space be- tween the sealing edge and the dust lip can result in apparent leakage at high tem- peratures or under pressure in the unit (→ see also “Short-term leakage”, page 381). Single packaging In addition to industrial packaging, many designs can also be supplied in in- dividual packaging in smaller quantities. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 359 X E D N I

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Seals for Rotary Applications The components are usually individually sealed in PE bags and provided with adhesive or printed labels with the com- ponent-specific data. Identical components in industry and single packaging are listed in the catalog program with different article numbers. Note: When opening the individual pack- ages, make sure that the component is not damaged. 11.5 STORAGE TIME The labels on the packaging units for Simmerring® specify the permissible storage and usability. This is either the defined “Best Before” date or the date of manufacture of the component. The shelf life of components made of the elastomer material NBR is 7 years. Com- ponents made of the elastomer material FKM have a shelf life of 10 years. Pre- lubricated components made of NBR or FKM have a maximum shelf life of 3 years. The storage conditions according to DIN 7716 or ISO 2230 must be observed. Printed batch numbers allow traceability back to the raw material, even for cata- log items. Map-marker-edit Batch number for traceability Fig. 170 Single packaging Fig. 171 Example of individual packaging with date of manufacture 360

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11. Handling and installation of radial shaft seals For standard products, a inclined position of 0.5° should not be exceeded. Examples: y Da 30 mm y Da 60 mm y Da 100 mm a = 0.25 mm a = 0.52 mm a = 0.87 mm The values given are only rough guide values. Under specific operating condi- tions, even a smaller inclination of the seal can have a negative effect on the sealing behavior. Play-circle  Installation of large oil seals Play-circle  Installation of Radiamatic® RPM41 a ØDa 11.6 INSTALLATION IN THE HOUSING BORE Note: The following descriptions and recommendations refer primarily to the installation of Simmerring® and PTFE radial shaft seals. For the installation of large radial shaft seals for applications in heavy industry, two illustrative assembly animations are available on the FST website (see also → “11.9 Joining and installing open radial shaft seals on site”, page 378). For pressing radial shaft seals into the housing bore, we generally recommend using a mechanical, pneumatic or hydraulic press-fit device together with a press-fit plunger (→ Fig. 173). The axis of the press-fit plunger is the axis of the bore. An inclined position is not permitted (→ Fig. 172). A metallic stop (press-fit plunger – housing) reduces the risk of incorrect assembly and increases the positioning accuracy of the radial shaft seal in the housing bore (→ Fig. 173). If the radial shaft seal is pressed into the housing during installation, for example against a shoulder, the seal (metal carrier) may be deformed if an installation tool with a suitable metallic stop to the hous- ing is not used. In this case, it is possible that the press-fit connection between the seal and the housing bore does not have sufficient overlap (→ Fig. 174). If this is not possible for design reasons, a reference stop point can be used for the installation tool and housing (→ Fig. 175). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 172 Misaligned position 361 X E D N I

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Seals for Rotary Applications Misaligned installation → Outer diameter is peeled off → Ring is clamped Fig. 173 Angular misalignment of the radial shaft seal to the housing bore during installation Fig. 174 Installation tool with metallic stop on the housing for more precise assembly of the Simmerring® 362

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11. Handling and installation of radial shaft seals Installation without metal stop: elastomer is incompressible → metal part is deformed I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Fig. 175 Deformation of radial shaft seal when installation against shoulder without metallic stop of installation tool to housing S L A E S C I T A T S Surface not sufficiently accurate (e.g. sand casting) Use of a reference surface as an axial stop surface for the installation tool Fig. 176 Installation with reference stop point During “bottom side first” installation, the force can be applied according to Variant A from → Fig. 177. If there is insufficient installation space for the installation tool between the sealing lip and the inner lin- ing of the radial shaft seal due to a small radial distance between the housing bore and the shaft surface, installation is possible using Variant B from → Fig. 177. How ever, this installation variant involves a higher risk of elastomer shearing or deformation of the metal part. G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 363 X E D N I

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Seals for Rotary Applications A B Fig. 177 Design details for installation tool for “bottom side first” installation Tool Housing ) x ( Øx Øx Øx Øx Øx ) x ( x ) X ( X Øx Øx X ØX (x), (X) → relevant for axial positioning in the housing Fig. 178 Design details for installation stamp for “bottom side first” installation 364

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11. Handling and installation of radial shaft seals When mounting “face first”, there is a risk of bending the seal if the diameter of the press-fit punch is too small (→ Fig. 179). When designing the installation stamp, the design guideline according to → Fig. 180 should be applied if possible. Installation diameter too small → ring is deformed Fig. 179 Deformation of radial shaft seal in case of incorrect geometry of the installation punch (diameter too small) Ø Stamp Ø RSS Ø RSS ‒ Ø Stamp = ΔØ Outer Ø up to 71 mm → ΔØ = 1.4 mm Outer Ø from 71 mm → ΔØ = 1.8 mm Axial stop between installation tool and housing for precise positioning of the Simmerring®. Fig. 180 Optimised design of the mounting plunger with the mounting direction shown (front side in front, force application via base side) (→ see page 331) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 365 X E D N I

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Seals for Rotary Applications When using pneumatic, hydraulic or me- chanical press-fit devices, the installation speed of the radial shaft seal in the hous- ing bore is of high importance. This has a direct influence on the resulting overlap and thus on reliable seating and the static sealing function.. If the installation speed is too high, the radial shaft seal may “spring back” or be- come misaligned. This can lead to incor- rect positioning of the radial shaft seal. In the case of Simmerring® with a me tallic adhesive part (type B and BS or C and CS), the installation speed should be 1,000 mm/min must not be exceeded. To minimize springback and incliniation of rubberized Simmerring®, it is recom- mended that the seal not be installed all at once. It should be completely relieved for approx. 1 mm before the final posi- tion for approx. one second in order to position it gently afterwards. In the case of Simmerring® with a rubber- ized adhesive part (type A and AS), the in- stallation speed should not exceed 100 mm/min. For Simmerring® with small diameters, speeds of up to 300 mm/ min are possible. Higher installation speeds must be checked. HAMMER INSTALLATION For hammer installation (often used for large seals), use a suitable installation plate or installation stamp (→ Fig. 183). If the point load during installation is too high, there is a risk that the seal will be de- formed and leakage may occur (→ Fig. 181). Permissible hammer installation Attention: Use installation plate! Fig. 181 and Fig. 182 Hammer installation 366

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11. Handling and installation of radial shaft seals GLUING IN SIMMERRING® In principle, Simmerring® of type BA do not have to be glued in place. If special circumstances arise, such as higher inter- nal housing pressure, excessively large pores in the housing or housing toler- ances that cannot be maintained, the Simmerring® should be glued in place with the following adhesives: y design BA: LOCTITE 480 (ensures optimum bond- ing between metal and elastomer) y Type B1, B2: LOCTITE 480 or Epple 33 (sealing com- pound) y slip rings: LOCTITE 243 During the bonding process, care must be taken to ensure that the adhesive does not get onto the mating surface or onto the sealing or dust lip. WETTING OF THE ADHESIVE PART FOR INSTALLATION Components with a rubberized adhesive part diameter (grooved or smooth) smaller than Ø 20 mm can usually be installed without installation aids (lubrication on the adhesive part). Without lubrication, however, there is a risk of damaging the seal due to excessive installation forces. Specifically, there is a risk of deformation of the metal part that is not visible from the outside (especially in combination with an incorrect installation tool and in- stallation process). Suitable installation aids for lubrication are: y oil or grease film Disadvantage: In the event of excessive lubricant application, medium adhering to the air side can be misinterpreted as leakage. In addition, the medium re- mains in the gap between the tight fit and the housing bore, resulting in a lim- ited tight fit (low disassembly force). When using oils or greases as installa- tion aids, care must be taken to ensure compatibility with the medium to be sealed and the sealing material. Ideally, the medium to be sealed should be used. y water-alcohol mixture An advantage of this variant results from the evaporation of the lubricant after installation. This results in a very good tight fit after a sufficiently long storage time (high deinstallation forces). In closed rooms, sufficient ventilation must be ensured and the generally ap- plicable work safety regulations must be observed. y adhesives (e.g. LOCTITE 243) It should be noted that many adhesives have exceptionally good lubrication and thus a low holding force before the actual curing process. Consequently, subsequent processes, such as leak testing when pressure is applied in the unit or other handling processes, which may result in a force acting on the press fit, may only be carried out after the adhesive has cured. y special installation aids (e.g. FRETAX AF281 from OKS) In the case of water-based installation aids, the required drying time between application and installation must be observed. If the residence time is too short, water remains in the sealing gap, which can lead to corrosion of the bore surface in steel housings. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 367 X E D N I

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Seals for Rotary Applications y if other components of the unit, e.g. bearings with an interference fit and the same nominal diameter, are pushed over the running surface, the diameter of the running surface must be reduced to avoid damage. SHAFT DIAMETER [mm] Up to 30 > 30 to 150 > 150 REDUCTION TO NOMINAL MEASURE [mm] 0.10 0.20 0.30 It should be noted that the resulting re- duction in the overlap between the seal- ing edge and the shaft surface can affect the sealing function. The smaller overlap leads to a reduction in friction, but also makes the system more sensitive to ex- ternal influences such as vibrations and contamination (smaller overlap of the dust lip). When installing other machine elements, such as rolling bearings, it must be en- sured that the installation is guided to avoid contact marks on the surface to be sealed. If the seals are installed in large quantities and a sufficiently long residence time be- tween application of the water-based instal- lation aid and installation is not feasible, solvent- based installation aids can be used if necessary. In this case, the occupational safety guidelines must be observed and there must be no interaction with the elas- tomer material, as this would have a nega- tive effect on the function of the static bond. 11.7 INSTALLATION ON THE SHAFT y for installation over sharp edges, e.g. a keyway and keyway connection on the shaft, the sharp-edged shaft area must be covered with a protective cap (→ Fig. 183) to avoid damaging the sealing lip y the wall thickness of the protective cap should be less than 0.5 mm to avoid over- expansion of the sealing lip. Important note: In the case of MSS1 and BABSL components, expansion of 0.5 mm in the radial direction must be avoided. Thinner wall thicknesses are therefore recommended (special materials may be required for the installation sleeves) y when installing a hydraulic power unit part with a preassembled seal, a center- ing bolt should be used to prevent tilting and thus damage to the sealing lip y when installing a long shaft, the use of a guide plate for parallel guidance of the shaft is recommended to prevent unac- ceptable deformation of the sealing lip y if parts of the hydraulic power unit with a press fit and the same nominal diame- ter are pushed over the running surface, the diameter of the running surface must be reduced by 0.2 mm to prevent damage to the running surface. The function of the seal is not impaired by the reduction of the diameter Map-Marker-Exclamation Avoid expansion in radial direction 368

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11. Handling and installation of radial shaft seals max. 0.5 mm (radial) Fig. 183 Installation over a shaft with sharp edges INSTALLATION MSS7 For easier installation and a tighter fit dur- ing operation, the race of the MSS7 can be mounted on the shaft with LOCTITE 243. Important note: MSS7 components from the catalog range are already pre-greased as shown in → Fig. 185. It is not recommended to separate the race (inner part) from the sealing part (BAUMSL). Due to the greasing carried out at the factory, the permissible storage time must be observed (see label on the packaging unit). Map-Marker-Exclamation MSS7 are pre-greased components 11.8 INSTALLATION OF SPECIAL DESIGNS INSTALLATION MSS1 Important notes: y for safe installation of the upstream sine sealing lip of the MSS1, a suffi- ciently long installation chamfer on the shaft is required to prevent the sine sealing lip from being turned up- side down and damaged. If this is not possible for space reasons, we recom- mend using a thin-walled installation mandrel which is centered radially to the shaft diameter y until the MSS1 is installed, it is recom- mended to leave the component in the packaging provided, as it cannot be stacked y MSS1 components from the catalog range are already pre-greased, as shown in → Fig. 184. Due to the greasing car- ried out at the factory, the permissible storage time must be observed (see label on the packaging unit) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 369 X E D N I

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Seals for Rotary Applications Grease filling Fig. 184 Installation of a Simmerring® MSS1 X Grease filling Fig. 185 Instructions for the installation and design of the installation tool for a Simmerring® of the MSS7 design. The dimension “X” required for the design of the installation tool can be requested from your contact person. 370

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11. Handling and installation of radial shaft seals INSTALLATION OF SIMMERRING® WITH SEALING LIP MADE OF PTFE The same guidelines apply to the instal- lation of Simmerring® with a sealing lip made of PTFE as to Simmerring® with a sealing lip made of elastomer in accord- ance with DIN 3760. It is important that the PTFE sealing lip is not damaged, especially when installing with the face in the installing direction. The use of a radially centered installation mandrel with a run-up inclination of 10° to 15° is recommended (→ Fig. 186). It should be noted that catalog parts in PTFE (B2PT) material are supplied in a non- pre-stretched state. Therefore, pre-ex- pansion to shaft dimensions before the actual installation process is advantageous. Map-Marker-Exclamation Pre-stretching advantageous with PTFE Shaft Shaft Installation mandrel Fig. 186 Installation of a Simmerring® with PTFE sealing lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 371 X E D N I

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Seals for Rotary Applications INSTALLATION OF SIMMERRING® CASSETTE SEAL Exchange y no reworking or replacement of the shaft required y in the case of designs which have a race without elastomer support on the inside diameter, a sealant may be required on the inside diameter Requirements for the shaft y tolerance: h8 y roughness: Metal and rubber ID/ rubber-only ID:: 1.6 ≤ Ra ≤ 6.3; Rz ≤ 25 metal ID only: 0.8 ≤ Ra ≤ 3.2; Rz ≤ 16 y chamfer: 2 x 15° ... 25° no sharp edges; must be rounded off y surface condition: NO scratches y heat treatment: not required y grinding: not required y machining helix removal: not required → Tab. 19 Diameter for the shaft lead-in chamfer see → 8.1, Tab. 19, page 330. Requirements for the housing y tolerance: H8 y roughness: metal and rubber OD/ rubber-only OD: 1.6 ≤ Ra ≤ 6.3; Rz ≤ 25 metal-only OD: 0.8 ≤ Ra ≤ 3.2; Rz ≤ 16 y chamfer: 2 x 15° ... 25° no sharp edges; must be rounded off y surface condition: NO scratches y heat treatment: not required y for metal-only outer diameter, the use of sealant is recommended, e.g. LOC- TITE 480 20° ±5° 2 mm Handling y handle seal with rubber gloves y hold the seal with two hands (grasping the outer diameter) y do not allow the seal to fall, if it does fall, scrap it y do not scratch/damage the outer diam- eter y do not damage the inner diameter with scratches y do not touch sealing lip y do not remove spring y working surface of the sealing lip must not be scratched/damaged 372

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11. Handling and installation of radial shaft seals y Case E (2-stage installation, only for “Soft Unitized” versions) (→ Fig. 191) • step 1: Installing the race on the shaft • step 2: Installation of the sealing ring in the bore (this version must be coordinated with FST) • installation shaft and bore INSTALLATION TYPES y Case A (with bearing stop) (→ Fig. 187) • step 1: Pressing into the bore • step 2: Installation on the shaft y Case B (without bearing stop) (→ Fig. 188) • step 1: Pressing into the bore • step 2: Installation on the shaft y Case C (parallel) (→ Fig. 189) simultaneously on bore and shaft y Case D (first on the shaft) (→ Fig. 190) • step 1: Installation on the shaft • step 2: Pressing into the housing bore (this version must be coordinated with FST) Step 1 Place Simmerring® cassette seal on the installation tool ➀ ➀ Step 2 Insert Simmerring® cassette seal on housing bore ➁ ➁ Step 3 Simmerring® cassette seal correctly placed Step 4 Pull out installation tool ➀ Step 5 Step 6 Insert shaft ➂ Axially-relieved Simmerring® cassette seal in place ➀ ➂ Fig. 187 Installation of Simmerring® cassette seal – Case A (with bearing stop) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 373 X E D N I

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Seals for Rotary Applications Step 1 Placement of the Simmerring® cassette seal on the installation tool ➀ Step 2 Insert Simmerring® cassette seal at housing bore ➁ Step 3 Simmerring® cassette seal correctly placed ➀ ➁ Step 4 Pull out installation tool ➀ ➀ Step 5 Step 6 Insert shaft ➂ Simmerring® cassette seal correctly placed ➂ Fig. 188 Installation of Simmerring® cassette seal – Case B (without bearing stop) Step 1 Placement of the Simmerring® cassette seal on the installation tool ➀ Step 2 Positioning of the guide ➁ ➀ ➁ Step 3 Simmerring® cassette seal correctly placed Step 4 Pull out installation tool ➀ ➀ Fig. 189 Installation of Simmerring® cassette seal – Case C (parallel) 374

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11. Handling and installation of radial shaft seals Step 1 Step 2 Placement of Simmerring® Insert the Simmerring® cassette seal on the installation tool ➀ cassette seal into the housing ➁ Step 3 Simmerring® cassette seal positioned ➀ ➁ Step 4 Pull out installation tool ➀ ➀ Step 5 Insert the shaft into the housing ➂ ➂ Step 6 Simmerring® cassette seal positioned Fig. 190 Installation of Simmerring® cassette seal – Case D (first on the shaft) Step 1 Sleeve installed on the shaft ➂ with a special tool ➀ ➂ ➀ Step 2 Fitting the sealing ring on a special installation tool ➀ ➀ Step 3 Sealing ring mounted in housing, tool stopped at bearing inner diameter Step 4 Pull out installation tool ➀ Step 5 Insert the shaft ➂ into the housing ➁ ➂ ➁ Step 6 Simmerring® cassette seal positioned I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 191 Installation of Simmerring® cassette seal – Case E (2-stage installation) 375 X E D N I

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Seals for Rotary Applications INSTALLATION OF SIMMERRING® COMBI SEAL Requirements for the housing y tolerance: H8 y roughness: metal and rubber OD/ rubber-only OD: 1.6 ≤ Ra ≤ 6.3; Rz ≤ 25 metal-only OD: 0.8 ≤ Ra ≤ 3.2; Rz ≤ 16 y chamfer: 2 x 15° ... 25° No sharp edges; must be rounded off y surface condition: NO scratches y heat treatment: not required y for metal-only outer diameter, the use of sealant is recommended, e.g. LOC- TITE 480 20° ±5° 2 mm Handling y proceed carefully so that the sealing lips are not damaged during handling and insertion of the shaft (applies spe- cially to splined shafts) Installation procedure y same installation instructions apply as for standard Simmerring® y carefully when inserting the shaft to avoid possible damage to the sealing lips Exchange y when a Simmerring® combination seal is replaced, the shaft must be replaced/ renewed to meet the hardness and tolerance requirements y for Simmerring® combi seals with metal outer diameter, a sealant is required on the outer diameter Requirements for the shaft y tolerance: h11 y roughness: 0.2 ≤ Ra ≤ 0.8 1.0 ≤ Rz ≤ 5.0 Rmax ≤ 6.3 y chamfer: 2 x 15° ... 25° No sharp edges; must be rounded off y surface condition: NO scratches, NO helix y heat treatment: Quenching and hard- ening (other option to be evaluated with FST Engineering). y removal of machining helix: required (other option to be evaluated with FST Engineering) y helix free grinding → Tab. 19 Diameter for the shaft lead-in chamfer see → 8.1, Tab. 19, page 330. Lubrication y grease must be applied before insert- ing the shaft into the combination seal y please request instructions for dein- y all inner surfaces of the combi-seal stallation (air side first) must be lubricated 376

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11. Handling and installation of radial shaft seals y for greasing by hand, the grease can be applied to the combi seal with a silicone brush (not a paint brush!) or spatula (wood) and distributed over the entire surface y normally this operation is performed after inserting the combination seal into the housing and before inserting the shaft Installation types y Case A (→ Fig. 192) • step 1: pressing into the bore • step 2: installation of the shaft y Case B: Parallel installation (→ Fig. 193) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Installation tool Housing S L A E S C I T A T S Fig. 192 Installation of Simmerring® combi seal – Case A Shaft Installation tool Housing Housing Shaft Shaft Fig. 193 Installation of Simmerring® combi seal – Case B (parallel) Guide G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 377 X E D N I

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Seals for Rotary Applications 11.9 JOINING AND INSTALLING OPEN RADIAL SHAFT SEALS ON SITE In some applications in heavy industry, replacing a radial shaft seal, e.g. for main- tenance work, involves considerable dis- assembly. The main shaft of a wind tur- bine is a good example of this. For the subsequent joining of the seal on the shaft, a special process is used to re- connect the two loose ends of the seal. The RK 15 cold bonding set holds the two loose ends of the seal perfectly alined in special jaws modeled on the profile of the gasket. The two-component adhesive thus joins the cut ends in precise alignment with each other. Map-marker-edit Time-consuming disassembly of the equipment on site is avoided For this reason, seals without a metal case are used for such applications. They are placed around the shaft in the form of a cut-open ring, then joined to form an endless ring and finally installed in the bore of the housing. Reliable joining of radial shaft sealing rings saves time-consuming disassembly of the equipment on site. High precision of the bonding device and practicality in application make it possible for custom- ers to carry out the work themselves. For such demanding applications, Freuden- berg Sealing Technologies offers radial shaft seals from its extensive product port- folio in the Radiamatic®, Seventomatic®, Enviromatic and TBM series. These seals can be cut open on site or are supplied already “open”. Play-circle  Assembly animation RK15 Fig. 194 Cold bonding set RK 15 for joining radial shaft seals on site 378

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11. Handling and installation of radial shaft seals 11.10 REPLACING RADIAL SHAFT SEALS When dismantling a radial shaft seal to be replaced, care must be taken not to damage the housing bore or the shaft surface. If it is possible to press the radial shaft seal out of a housing bore, use a suit- able dismantling punch (if necessary, de- pending on the design environment, the previously used assembly punch can also be used) (→ chapter “Services – Installa- tion and Deinstallation aids”, page 14). If pressing out is not possible, the metal part can be drilled on the bottom or front side. It is essential to ensure that no metal chips remain in the space to be sealed (damage to bearing, contamination of sealing point). Then pull the seal out of the bore using a suitable tool (e.g. impact tool, → Fig. 195). Measures for this are: y replace shaft bushings (replaceable race or hardened bearing ring manufactured without lead and available on the mar- ket). The disadvantage of this design is reduced heat dissipation from the seal- ing contact due to the additional part- ing line between shaft and bushing. This effect is exacerbated if adhesive is used to fix the bushing y rework the shaft surface to the next smallest available shaft diameter (in the DIN range) and use of the appro- priate radial shaft seal y select a different press-in depth into the bore y install spacer rings (→ Fig. 198) Fig. 195 Impact tool for mounting and dismounting seals Dismounting the radial shaft seals: it is not recommended to use a hook-shaped tool to reach behind, between the shaft and sealing lip. There is a risk of damaging the shaft surface during this process, which may result in leakage during further operation of the unit. When repairing or overhauling a hydraulic power unit, new seals must always be in- stalled. The sealing lip of the new radial shaft seal must not be positioned on the position of the old running point (risk of leakage). Fig. 196 Design of the sealing point with replaceable slip ring on the shaft I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 379 X E D N I

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Seals for Rotary Applications Original installation Installation in case of repair Fig. 197 Reworked shaft (smaller diameter and use of a suitable, available shaft seal) y use shaft sleeves (e.g. WSH). The wall thickness of the shaft sleeves available on the market is approx. 0.3 mm. After assembly, this results in an enlarged di- ameter of the mating surface of approx. 0.6 mm. If no radial shaft seal adapted to the 0.6 mm increased shaft diameter is available, the originally used dimension of the radial shaft seal must be used. This results in a higher sealing lip over- lap and increased friction. This means that a shorter service life can be expect- ed (compared to the original pairing of original shaft diameter and radial shaft seal) y It is not recommended to use type MSS1, BABSL or PPS on a mating posi- tion which has been enlarged by 0.6 mm by mounting a shaft sleeve 380 Original installation Installation in case of repair Fig. 198 Installation in case of repair – replacement Simmer- ring® with axially offset position. Blue dashed line shows running track of original position. Red dashed line shows position of the running track with axially offset radial shaft seal

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12. FAILURE ANALYSIS 12. Failure analysis See also → chapter “Materials and Process engineering – 9. Damage analysis“, page 163. SHORT TERM LEAKAGE One form of temporary leakage in greased radial shaft seals can be so-called apparent leakage. 12.1 LEAKAGE DEFINITION – THE STANDARD, LEAKAGE TERMS, CAUSE, CLASSIFICATION Under the prescribed operating conditions, leakage is determined by the amount of the fluid to be sealed that exceeds the functional lubricant film at the sealing edge in a defined time during operation, and leads to dripping of the fluid to be sealed. This amount of fluid is referred to as leakage. Leakage classes can be defined as follows: Tight No moisture can be detected on the seal. A lubricant film may be visible under the sealing edge. Moist Visible oil presence between sealing lip and shaft. The air side of the radial shaft seal may be moist. Wet Visible oil presence between sealing lip and shaft. Fluid collects on the cover/ housing or/and fluid trace is possible on the cover, but does not drip yet. LEAKAGE Detectable leakage, typically dripping on the outside of the housing starting from the air side of the seal. Leakage can occur continuously or for a short time. This is often due to excessive grease filling between the sealing lip and the dust lip. The grease expands under the influence of temperature. When pressurized (e.g. during a test of the hydraulic power unit), the available space between the sealing lip and the dust lip is reduced. In both cases, grease can escape between the dust lip and the shaft if the filling quantity is too great during installation. The leakage of the fluid can be interpreted by the end customer as an oil leakage. Short-term leakage can also be caused by short-term disturbances of the sealing sys- tem, e.g. by small dirt particles which tem- porarily disturb the sealing mechanism and are transported out of the sealing gap again during further operation. ANALYSIS OF LEAKAGE CAUSES: STATIC AND DYNAMIC LEAKAGE In the case of radial shaft seals, a distinc- tion is made between two types of leakage (→ chapter “Services – Damage Analysis”, page 16): y static leakage possible at the outer surface (between outer diameter and housing bore) or at the sealing lip (be- tween sealing lip and shaft surface) when the shaft is not rotating y dynamic leakage occurs at the sealing lip when the shaft rotates I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 381 X E D N I

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Seals for Rotary Applications STATIC LEAKAGE Static leakage at the housing bore y bore diameter too large y housing bore too rough, especially critical for radial shaft seal with me- tallic interference fit y damage to the press fit due to e.g. sharp-edged chamfer area and/or ex- cessively steep housing chamfer • metallic press fit gets cross-grooves • rubberized press fit can be sheared off Static leakage at the shaft y shaft diameter too small and/or hous- ing offset too large y damage to the shaft surface (e.g. axi- al scoring due to mounting of a bear- ing adjacent to the sealing point) y damage to sealing lip (e.g. due to sharp-edged chamfer or keyway) y inverting of sealing lip during installa- tion (e.g. due to unsuitable chamfer) y lifting of the sealing lip due to vacuum in the hydraulic power unit DYNAMIC LEAKAGE Dynamically induced leakage at the seal- ing lip occurs far more frequently than static leakage. Compared with static leakage, the causes are more complex. The most important influencing factors are discussed below. Shaft y sharp-edged or excessively small in- stallation chamfer y scratches, e.g. caused by mounting a bearing on the shaft. If other compo- nents of the unit, e.g. bearings with an press fit and the same nominal diame- ter, are pushed over the running surface, the diameter of the running surface must be reduced to prevent damage – by 0.10 mm for shaft diameters up to 30 mm, by 0.2 mm for shaft diam- eters from > 30 mm to 150 mm and by 0.30 mm for shaft diameters > 150 mm. In general, the function of the Simmerring® is not affected by this reduction in the shaft diameter. y blowholes in the running track area of the radial shaft seal, e.g. in the case of cast materials or flame-sprayed coatings (pores with a dimension of < 0.05 mm are permitted) y falling below or exceeding the recom- mended roughness values of the shaft surface can cause leakage (e.g. due to heavy wear) y lead (= conveying surface structures) on the shaft surface For recommendations on roughness para- meters, see → “8.1 Shaft design”, page 322. In addition to established test methods such as the filament method, modern measurement methods can be used to characterize shaft surfaces and assess their suitability as RSS mating surfaces (→ “Thread method”, page 405), → chapter “Services – Test Benches”, page 17). LUBRICANT The lubricant has a significant influence on the sealing behavior. The complex structure of the lubricants, the interrela- tionship of the individual additives and the interactions with the elastomer of the radial shaft seal can cause y radial shaft seals to show chemical in- teractions with the fluid to be sealed, especially at the sealing edge Map-marker-edit Reduction of the diameter of the running surface 382

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12. Failure analysis Pressure The relevant pressure for the sealing point is the pressure difference between the fluid side (spring side) and the air side of the seal (ambient pressure). Overpressure on the fluid side (e.g. caused by thermal expansion of the air in non- vented hydraulic power unit) increases the specific contact pressure of the sealing lip on the shaft surface. This increases both the thermal load on the elastomer and the lubricant in the sealing gap as well as the mechanical load. This can result in in- creased wear of the sealing lip, increased shaft run-in and, consequently, a shorter operating life of the radial shaft seal. For pressures > 0.5 bar, special sealing lip de- signs are required. For further information see → “7.1 Designs for pressure applica- tions”, page 316. Excess pressure on the air side reduces the contact pressure of the sealing lip on the shaft surface and can lead to a mal- function of the sealing function. Contamination Internal or external contamination can cause radial shaft seals to fail. The dirt particles can get into the sealing gap and disrupt the dynamic sealing function or lead to excessive wear of the sealing edge and shaft. As a result of internal or exter- nal contamination, the service life can be significantly reduced. Map-Marker-Exclamation Poor lubrication caused by insuffi- cient wetting Simmerring® Selector y reactive substances to be deposited on the shaft surface in the immediate proximity of the sealing edge. This can disrupt the dynamic sealing function. In addition, it is also possible that the exchange of lubricant in the sealing gap is inhibited or even completely prevented by the deposits. This can lead to insufficient lubrication and/or thermal overload at the sealing lip Despite a sufficient supply of lubricant, poorly wetting fluids (e.g. PG oils or high viscosities) can lead to poor lubrication at the sealing lip of radial shaft seal. Poor lubrication due to insufficient wetting occurs more frequently at low oil sump temperatures and with the combination of radial shaft seals made of some FKM materials and PAG-based fluids. OPERATING CONDITIONS AND ENVIRONMENTAL INFLUENCES The sum of operating conditions and envi- ronmental influences have a significant ef- fect on the sealing behavior of radial shaft seal. The selection of suitable seal designs and materials depends to a large extent on the various operating conditions. Therefore, the Simmerring® selector is recommended. A selection of relevant conditions is dis- cussed below: Temperature A large number of influencing variables are relevant for the thermal load on the sealing system, including the combination of oil sump temperature, speed, pressur- ization, lubricant supply and lubricant. As a result, the sealing edge temperature can be considerably higher than the oil sump temperature. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 383 X E D N I

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Seals for Rotary Applications Handling Mechanical influences Dirt from outside Chemical damage RSS wear Transportation Speed Operating conditions UV Roughness of the shaft Storage Assembly Shaft Sealing lip Eccentricity Shaft Sand Mud Ozone Medium Vibrations Dust Temperature Overpressure Sealing medium Construction Water Elastomer material Material Hydraulic power unit Seal Bore Medium Lead on shaft Molding sand Medium/medium level Metal abrasion Temperature Dirty medium Speed Corrosion Elastomer Material Shaft material/ roughness Elastomer material Corrosion protection Surface structure of shaft Lubricant Abrasive particles Production Dirt from inside Thermal damage Wear of the running point Fig. 199 Possible causes of failure of radial shaft seals Map-marker-edit MSS1 and modified catalog goods with bonded elements made of non- woven or PTFE If there is an increased dirt load that ex- ceeds the operating limits of a conven- tional Simmerring® with a dust lip, a modified catalog component combined with a non-woven disc from Freuden- berg or the MSS1 design can be used (see → “9. Modified catalog goods”, page 333). Internal contamination can be caused, for example, by abrasion of rotating parts (e.g. bearings or cogs) or residues from the manufacturing process (e.g. molding sand or blasting material). External contamination can be caused by the specific application and environmen- tal conditions (e.g. dust, sand, dirt, fibers, or cleaning media as used in the food in- dustry). Play-circle  Application example MSS1 384 CLASSIFICATION OF LEAKAGE DURATION: SHORT-TERM AND LONG-TERM Short-term failure Short-term failure or early failure is under stood to mean premature failure of the sealing system. The period of time until the leakage occurs is application- specific and strongly depends on the operating conditions. In many cases, the term “early failure” is used when the unacceptable leakage occurs with less than 100 operating hours or, for example, with a mileage of less than 10,000 km. Long-term failure Long-term failure is defined as the failure of the sealing system after the hydraulic

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12. Failure analysis power unit has been in operation for an extended period of time (→ “12.1 Leak- age definition”, page 381). Based on data from the analysis of field returns and test rig trials, the influences on early and long-term failures are to be assessed differently (→ Tab. 22). Appropriate assembly training (→ chapter “Services – Training”, page 19) or advice on the correct machining of shaft surfaces can prevent most errors from occurring. It is important that the seal and hydraulic power unit manufacturer, and the user, work closely together and proceed sys- tematically during the fault analysis. diagram “Possible causes of failure of radial shaft seals” (→ Fig. 199) has proven to be a useful analysis tool for damage assessment. This diagram can be used to systematically isolate faults. There is rarely a single cause of leakage. Only the interaction of several factors usually leads to the failure of the sealing system. Map-Marker-Exclamation As a rule, several factors lead to leakage For the damage analysis, it is therefore necessary for the user to provide all rele- vant information concerning the damage and to send the uncleaned seal and shaft and, if necessary, a lubricant sample for the damage analysis. There are a large number of influencing variables with interactions that can affect the sealing effect of a radial shaft seal in the medium and long term. The Ishikawa The damage analysis sheet from FST can be requested for collecting and docu- menting the installation and operating conditions. Damage analysis sheet Shaft machining Improper installation Faulty seal Chemical incompatibility with sealed fluid Sealing environment Operating conditions Tab. 22 Causes of failure PROPORTION OF SHORT-TERM FAILURE PROPORTION OF LONG-TERM FAILURE 30 % 35 % 5 % 10 % 10 % 10 % 5 % 0 % 10 % 40 % 20 % 25 % I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 385 X E D N I

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Seals for Rotary Applications PRESENTATION OF VARIOUS CASES OF DAMAGE TO THE SIMMERRING® FEATURE FIGURE Sealing edge in as-new condition In as-new condition, the sealing lip has an approxi- mately sharp-edged sealing edge. The running track required for the dynamic sealing function forms after a short period of operation Sealing edge with contact surface A well-settled contact surface after an operating time of > 500 hours The sealing edge is free of deposits, cleanly set and has a wear band width < 0.5 mm Cracking A thermally highly stressed outer edge layer of the sealing edge with hard deposits and axially running cracks in the contact surface Severe impairment of the dynamic sealing function. Depending on the extent of the axial cracks, there may also be static leakage at the sealing edge when the hydraulic power unit is at a standstill Possible cause: thermal overload Hard deposits A thermally stressed sealing point with hard deposits of the fluid to be sealed in the area of the contact sur- face Severe reduction of the dynamic sealing function Possible causes: thermal overload of the sealing fluid in the sealing gap 386

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12. Failure analysis FEATURE FIGURE Softening Very strong chemical reaction with the fluid to be sealed or with a substance on the air side of the sealing point (e.g. cleaning medium) Severe impact on the dynamic sealing function Possible causes: Incompatibility with the fluid to be sealed off Abrasion Very high sealing lip wear with resulting dry elasto- mer abrasion Possible cause: poor lubrication Bubble formation Complex mechanical, chemical and thermal interaction in the area of the sealing gap (mostly at the air-side contact surface of the sealing point) sometimes leads to fluid-filled bubbles on the elastomer surface. Severe impact on the dynamic sealing function Possible causes: Incompatibility and/or thermal over- load with the fluid to be sealed Grooving Very heavy sealing edge wear with heavy grooving on the circumferential side in the contact surface Possible cause: insufficient lubrication and/or exces- sive pressurization of the sealing lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 387 X E D N I

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Seals for Rotary Applications PRESENTATION OF VARIOUS CASES OF DAMAGE TO THE SIMMERRING® FEATURE FIGURE Contamination Very heavy contamination on the air side contact surface of the sealing lip Possible cause: strong external impact with dirt or other particles without sufficient protection of the sealing point. Particles can lead directly to a malfunction of the sealing system. However, premature wear of the sealing edge or shaft due to dirt is also possible Hollow groove Very significant sealing lip wear with a very strong expression of a cove on the air-side contact surface of the sealing lip Possible cause: strong pressurization of the sealing lip, possibly in combination with deficient lubrication due to a lubricant film breaking off in the sealing gap Sealing edge damage Local mechanically caused damage to the sealing edge ensures immediate leakage after start-up of the unit. The disturbance of the tribological system prevents the formation of a contact surface. Between the damaged locations, the sealing edge is often in as-new condition Possible cause: incorrect mounting (no mounting mandrel with unfavorable shaft geometry with sharp- edged chamfers), incorrect handling Deposits in the helix A thermally stressed sealing point with hard deposits of the fluid to be sealed in the helix ribs of the sealing lip Severe impairment of the dynamic sealing function Possible causes: thermal overload of the sealing fluid in the sealing gap 388

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12. Failure analysis SUMMARY FST radial shaft seals are proven, robust and reliable sealing elements. However, due to complex alternating effects in the tribological system, they are subject to natural wear. Determining the cause of leakage is therefore a demanding and complex process. Damage patterns such as those shown above are examples of the most important causes of radial shaft seal failure. The actual cause can only be determined by a careful analysis of the shaft, radial shaft seal and, if necessary, lubricant. This document can be used to provide the relevant information on the operating and installation conditions. If a damage analysis sheet, completed as fully as pos- sible, and a carefully dismantled RSS and the shaft in an uncleaned condition are available, as well as a lubricant sample if necessary, a cause for leakage can be identified in many cases. Ideally, suggestions for improving the sealing system can be derived from the results of the investigation (→ chapter “Services – Damage Analysis”, page 16). FST provides a damage analysis sheet for the examination of radial shaft seal- ing rings from tests or field runbacks. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 389 X E D N I

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Seals for Rotary Applications 12.2 INCORRECT HANDLING AND CORRECTIVE MEASURES The compilation of possible trouble spots during the installation and handling of Simmerring® at the user’s premises is intended to help identify trouble spots and take appropriate remedial action. Please use the opportunity to get tech- nical advice from a Freudenberg Sealing Technologies technician. 1.0 GOOD S INPUT 1.1 STORAGE IN WAREHOUSE 1.2 TRANSPORT TO ASSEMBLY SITE 1.3 STORAGE AT ASSEMBLY SITE INSTALLATION 2.1 TOOL 2.2 SHAFT 2.3 HOUSING 2.0 INSTALLATION PREPARATION 3.0 HANDLING HYDRAULIC POWER UNITS Fig. 200 Representation of the flow of goods as a structural overview of the error possibilities 390

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12. Failure analysis SOURCES OF ERROR AND CORRECTIVE MEASURES ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 1.0 GOODS INPUT Damage to the packaging unit Contamination of Simmerring® Shortened life time until immediate leakage Transport packing not in order Damage to the packaging unit Damage to Simmerring® Shortened life time until immediate leakage Transport packing not in order Checking parts for contamination, visual and dimen- sional changes; improving handling of the packaging Checking parts for damage, visual and dimensional changes; improving handling of packaging 1.1 STORAGE OVER A LONGER PERIOD OF TIME/TEMPORARY STORAGE (CONSUMPTION QUANTITIES, PROVISION FOR ASSEMBLY) Non-compliance with the storage conditions according to DIN 7716 Installation of defective Simmerring® Shortened life time until immediate leakage Non-compliance with storage condi- tions; exceeding the prescribed maximum storage times Observe storage conditions acc. to DIN 7716 uncondi- tionally Contamination of Simmerring® Installation and use of dirty Simmerring® No influence until immediate leakage as well as shortened service life Dirt Damage to the Simmerring® Installation of damaged Simmerring® Immediate leakage or shortened service Premature aging due to improper life storage 1.2 TRANSPORT (FROM INTERMEDIATE STORAGE TO ASSEMBLY SITE) Damage to the packaging Contamination of Simmerring® Shortened life time until immediate Improper handling leakage Only open original packaging at assem- bly site; dispose of contaminated parts if necessary Only open original packaging at the assembly site; dispose of damaged parts Blocking and special release of parts in damaged packaging; checking for contamination; staff training I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 391 X E D N I

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Seals for Rotary Applications SOURCES OF ERROR AND CORRECTIVE MEASURES ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 1.3 INTERIM STORAGE AT THE ASSEMBLY SITE (CONSUMPTION QUANTITIES) Contamination of Simmerring® Installation of a contaminated Simmerring® Open bearing of pregreased Simmerring® Grease contamination Unsuitable storage container Contamination, damage to the Simmerring® No influence until immediate leakage as well as shortened service life; leakage as well as shortened service life due to in- creased wear caused by dust or dirt Dirt from the environment; solar radiation; ozone pollution Only open original packaging at assembly site; dis- pose of contaminat- ed parts if necessary No influence until immediate leakage as well as shortened service life due to increased wear Dirt from the environment; solar Always cover the packaging unit; protect from dust radiation; ozone and dirt; only remove pollution the required con- sumption quantity No influence until immediate leakage as well as short- ened service life due to increased wear Accumulation of dirt and moisture in the storage container; sharp edges; exposure to light and ozone Use easy-to-clean and coverable containers without sharp edges 2.0 PREPARATION OF THE SIMMERRING® AND THE INSTALLATION SPACE FOR INSTALLATION Improper opening or removal from packaging Cuts or similar damage to the outer diameter; spring jumping off; installa- tion of Simmerring® without spring Immediate leakage to shortened service life Sharp-edged or unsuitable tools or method of opening Greasing the Simmerring® with contaminated grease Contamination of the Simmerring® Immediate leakage to shortened service life due to increased wear Dirt; dirty or unsuitable greasing tool (e.g. bristle brush) Suitable packaging and tools; special care and instruction of the fitter; installation and handling training Protect grease containers from contamination and cover when not in use 392

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12. Failure analysis ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 2.0 PREPARATION OF THE SIMMERRING® AND THE INSTALLATION SPACE FOR INSTALLATION Greasing the Simmerring® with unsuitable grease Increased wear sealing lip and dust lip Immediate leakage to shortened service life due to increased wear Solids in the grease interfere with the sealing mechanism or lead to accelerat- ed wear; chemical reaction with fluid to be sealed Check grease for compatibility with the medium to be sealed; never use graphite grease or other media contain- ing solids Initial lubrication (oil) of the Simmer- ring®, shaft or bore with contaminated oil Contamination of the Simmerring® Immediate leakage to shortened service life due to increased wear Dirt; dust Protect oil reservoir from contamina- tion and cover when not in use; use suitable, clean tool for initial lubrication Initial lubrication (oil) of the Simmer- ring®, shaft or bore with unsuitable oil Chemical influence on the seal material; Shortened service life due to increased stick slip wear Unfavorable lubrica- tion and wetting; interaction with elas- tomer material or the medium to be sealed Use medium to be sealed for initial lubrication Too much grease between sealing edge and dust lip Grease leakage during installation or Apparent leakage operation Wrong grease dosage General recommen- dation: max. grease quantity for standard parts approx. 40% of the grease space (be- tween sealing edge and dust lip) No or too little grease Insufficient lubrica- tion of the dust lip; increased dirt ingress; elastomer abrasion Shortened service life due to excessive temperatures in the tribological system or premature wear Incorrect instruction or incorrect dosage quantity Position grease quantity on dust lip I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 393 X E D N I

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Seals for Rotary Applications SOURCES OF ERROR AND CORRECTIVE MEASURES ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE Lubrication on wrong position Insufficient lubrication of the dust lip Shortened service life due to excessive tem- peratures in the tribo- logical system or premature wear; apparent leakage Incorrect instruction or incorrect dosing quantity; incorrect greasing device or incorrect greasing mandrel Use pre-greased Simmerring®; change the design of the grease dispenser Applying the grease Contamination; interaction with internal or external medium, damage Immediate leakage to shortened service life Dirt; dust; application tool; cleaning tool; damage or sharp edges on the lubri- cation mandrel Pay attention to cleanliness; use suitable tools; inform and train personnel Greasing of a Simmerring® with- out dust lip when the seal is on the outside (e.g. gear- box outlet) Apparent leakage (due to oiling out of the applied grease) No consequences for the sealing function, but cus- tomer complaint due to apparent leakage possible Insufficient/incor- rect information Pay attention to cleanliness, use suit- able tools, inform and train personnel 2.1 INSTALLATION: INSTALLATION TOOL/ INSTALLATION SLEEVE/ INSTALLATION SYSTEM/ASSEMBLY SITE Incorrect design of the installation tool Damage to the seal, spring coming off, misalignment of Simmerring® in housing No to immediate leakage; shortened service life; short- ened service life due to uneven wear; colli- sion with neighbor- ing components Incorrect design of the assembly chamfer (→ “11. Handling and installation of radial shaft seals”, page 361) See suggestions in → “11. Handling and installation of radial shaft seals”, page 361 Dirty installation tool Contamination of RSS; skewing of RSS in housing; reduction of retaining forces; position change after installation No to immediate leakage; shortened service life; short- ened service life due to uneven wear; collision with neigh- boring components Improper handling or storage of the in- stallation tool Training of personnel (→ “11. Handling and installation of radial shaft seals”, page 361) 394

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12. Failure analysis ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 2.1 INSTALLATION: INSTALLATION TOOL/ INSTALLATION SLEEVE/ INSTALLATION SYSTEM/ASSEMBLY SITE Use of incorrect installation tool Damaged installation tool Damage to RSS; mis- alignment of RSS in housing; incorrect position of RSS in housing; reduction of retaining forces; change of position after installation Damage to RSS; mis- alignment of RSS in housing; reduction of retaining forces; change of position after installation No to immediate leakage; shortened service life; short- Confusion/no ened service life due assignment of RSS to Training of personnel; installation instruc- to uneven wear; collision with neigh- boring components No to immediate leakage; shortened service life; shortened service life due to un- even wear; collision with neighboring components; change in position after installation installation tool tions Improper handling or positioning of the installation tool Training of the personnel; regular inspection of the installation tool Press-in force too high when instal- lation to stop Deformation of the Simmerring® (deformation of the metal case) Immediate leakage to shortened service Press-in force too high/installation on life stop Reduce press-in force; force limita- tion; do not press in the end stop on the installation mandrel to the stop: path limitation Axial position of RSS in housing or on shaft not correct Sealing lip and dust lips run in the wrong No influence until immediate failures/ place early failures Incorrect design of the mounting sleeve Damage to the seal; spring coming off No to immediate leakage; shortened service life Installation mandrel or installation device not matched to RSS and installation space Check the position of the RSS; design of the installation tool to match the geometry of the RSS and the in- stallation space Incorrect design of the mounting cham- fer (→ “11. Handling and installation of radial shaft seals”, page 361) See proposals in → “11. Handling and installation of radial shaft seals”, page 361 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 395 X E D N I

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Seals for Rotary Applications SOURCES OF ERROR AND CORRECTIVE MEASURES ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE Dirty installation sleeve Damaged installation sleeve Contamination of RSS, damage to RSS (sealing edge/dust No to immediate leakage; shortened service life due to lip) uneven wear Improper handling or storage of the installation sleeve Training of personnel Damage to RSS (sealing edge/ dust lip) No to immediate leakage; shortened service life due to uneven wear Improper handling or position of the installation sleeve Training of personnel; regular inspection of the assembly sleeve Use of incorrect installation sleeve Damage to RSS (sealing edge/ dust lip) No to immediate leakage, shortened service life due to uneven wear Lack of information for personnel Training of personnel Use of no installation sleeve Damage to RSS (sealing edge/ dust lip); invert dust lip No to immediate leakage, shortened service life due to uneven wear Lack of information for personnel Training of personnel Improper hammer installation Installation without suitable tool (punch or plate); RSS is not mounted evenly over the circumfer- ence (especially with large RSS); spring coming off No to immediate leakage; shortened service life due to uneven wear Unsuitable or no installation tool (plate) for even force distribution on the RSS Provision of suitable installation tools for hammer installation; training of personnel Unsuitable installation system (e.g. press) Misalignment; excessive installa- tion speed; insuffi- cient punch force of the system; pressure build-up when installing RSS in closed housing No to immediate leakage; shortened service life due to uneven wear; collision with adja- cent components; change of position after installation Installation system not adapted to the specific installation process Selection of a suitable installation system (→ “11.6 Installation in the housing bore,” page 361) 396

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12. Failure analysis ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 2.1 INSTALLATION: INSTALLATION TOOL/ INSTALLATION SLEEVE/ INSTALLATION SYSTEM/ASSEMBLY SITE Unsuitable assembly site (e.g. workbench) Contamination; un- favorable environ- mental influences (e.g. direct sunlight; humidity; ozone); no sufficiently stable base available No to immediate leakage; shortened service life due to uneven wear; position change after installation Incorrect selection of the assembly site Suitable assembly site with regard to cleanliness; environ- mental influences and stability 2.2 SIMMERRING® RUNNING POINT (SHAFT) AT THE ASSEMBLY SITE Scratched shaft Damage to the sealing lip when inserting the shaft, rapid wear of the sealing edge and/ or dust lip during oper- ation, scratches in the area of the contact point of the sealing edge interfere with the sealing function Immediate leakage to short- ened service life Transport damage; lack of shaft protec- tion; improper storage and han- dling of the shaft Check shaft before installation; use suitable protective covers and transport containers for shafts and associated components; do not store or transport shafts in bulk Dirty shaft Damage and contamination of the sealing lip when inserting the shaft Immediate leakage to short- ened service life No shaft protection; unsuitable transport containers; damage to shaft during han- dling Clean the shaft before installation; use suitable protec- tive covers and transport containers Corroded shaft Damage to and con- tamination of the sealing lip during installation on the shaft or during oper- ation, possible dam- age to the sealing lip; Interactions with the medium to be sealed Immediate failures to shortened service life No or insufficient corrosion protection; too high air humidity; too long storage; unsuitable transport containers or missing cover Check shafts for corrosion before in- stallation; never use corroded shafts; use suitable corrosion protection agents; rework corroded shafts I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 397 X E D N I

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Seals for Rotary Applications SOURCES OF ERROR AND CORRECTIVE MEASURES ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE Use of cast iron shaft Casting surface with large pores or Immediate failures to shortened service Blowholes on the surface larger blowholes life 0.05 mm Use of a suitable shaft material for the counter point Interaction of the corrosion protection agent with the Simmerring® materi- al or the medium to be sealed or the applied grease Immediate failures to shortened service life Coordinate with FST; test corrosion protec- Unsuitable material tion agents in the combinations or corrosion protection agents laboratory for compatibility with the Simmerring® material and the medium to be sealed Corrosion inhibitor 2.3 HOUSING BORE Two-part housing Combination with incorrect Simmer- ring® holding part design Static leakage Unsuitable adhesive part design (B1 or B2 or B or C accord- ing to DIN) Die-cast housing Pores; blowholes; casting sand Static leakage; increased wear to shortened service life due to casting sand Casting quality not sufficient; insuffi- cient cleaning Die-cast housing (Al, Mg) Adhesive fit not sufficient; skewed position; spring back or migration of the Simmerring® (with outer rubber lining) Shortened service life; collision with adjacent building parts Roughness of housing bore not according to specifi- cation; unsuitable adhesive part design Select RSS with suit- able adhesive part design; one-piece housing; select outer rubber coating or partial rubber coat- ing; use sealing lac- quer or adhesive Pores and blowholes maximum one third of the adhesive part width; improve cleaning Type BA (A acc. to D IN) and corre- sponding types with dust lip Rmax < 25 µm Ra = 1.6 … 6.3 µm Rz = 10 … 25 µm Type B1 or B2 (B or C acc. to D IN) and cor- responding types with dust lip Rmax < 16 µm Ra = 0.8 … 3.2 µm Rz = 6.3 … 16 µm 398

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12. Failure analysis ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 2.3 HOUSING BORE Die-cast housing (Al, Mg) or plastic housing For type B1 or B2 (B or C acc. to DIN) electrochemical cor- rosion, loss of cover- age due to different thermal expansion coefficients Static leakage, change of axial position, damage to metal part or housing Electrochemical reaction of shaft and metal case RSS materials, different thermal expansion coefficients of shaft and stiffening plate RSS materials Die-cast housing (Al, Mg) Damage to the bore with metallic press fit Static leakage; shortened service life; bore damaged in case of repair Unsuitable adhesive part design Burr or sharp edge on chamfer in housing bore Elastomer shearing off at the outer diam- eter of type BA (A ac- cording to DIN); misalignment; spring- back of Simmerring® Static leakage, change in axial position Burr formation at the transition from chamfer to bore; chamfer geometry not acc. to specifica- tion Coordination of housing bore design (chamfer geometry, depth including tolerance) and RSS geometry (width and chamfer) Cylindrical section of RSS is not complete- ly mounted in cylin- drical part of hous- ing bore in final installation position Static leakage; change in axial position; skewing of RSS to housing Unsuitable design of the geometry of the housing bore (chamfer, depth including tolerance) Housing bore Shearing of rubber; Simmerring® not installable Static leakage Chamfer too large; chamfer too small Use suitable material combination RSS with elastomer seat: Type BA (A to DIN) and corresponding types with dust lip Use suitable RSS with elastomer seat: Type BA (A according to DIN) and corre- sponding types with dust lip Housing free of burrs Comply with the specifications on the design of the housing bore (→ “8.2 Design of the housing”, page 331) Select chamfer angle 15 … 20°; Comply with the specifica- tions on the design of the housing bore (→ “8.2 Design of the housing”, page 331) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 399 X E D N I

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Seals for Rotary Applications SOURCES OF ERROR AND CORRECTIVE MEASURES ERROR SOURCE POSSIBLE ERROR CONSEQUENCES FOR THE SEALING FUNCTION CAUSE OF THE WEAKNESS CORRECTIVE MEASURE 3.0 HANDLING OF HYDRAULIC POWER UNITS WITH ALREADY INSTALLED SEAL IN THE PRODUCTION LINE AND DURING TRANSPORT Sealing point is stored unprotected Sealing point is stored unprotected Contamination or hardening of the elastomer material due to environmen- tal influences (temperature, direct sunlight, ozone) Damage to the seal or the sealing point (shaft) in the installa- tion state Shortened service life until immediate leakage Dirt and dust in the environment; UV light; ozone Shortened life time until immediate leakage Mechanical action from the outside Reaction between the running-in oil and anti-corrosion oil Reaction between inlet oil; anti-corro- sion oil; fluid to be sealed in operation and elastomer ma- terial Shortened service life to immediate leakage Reaction products in the fluid, swelling or volume change of the elastomer, changes in the me- chanical properties of the elastomer Corrosion of shaft or housing Corrosion at the sealing lip contact area Shortened service life High humidity; in- sufficient corrosion protection Transportation Spring jumping off Shortened service life Unsuitable trans- port containers Suitable covering of the sealing point to protect against nega- tive environmental influences such as ozone; UV light; temperature and dirt Suitable covering of the sealing point to protect against damage Ensure the compati- bility of the individu- al components of the tribological system: elastomer, anti-cor- rosion oil, running-in oil, grease (if applica- ble), fluid to be sealed under the op- erating conditions present in operation Corrosion protection; cover the sealing point; limit air humidity; if neces- sary cover the pack- aging with VCI paper or add silica gel bags Suitable transport containers; carry out spring seat check before installation 400

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13. SIMMERRING® ENGINEERING 13. Simmerring® engineering Global Simmerring® Engineering 13.1 COMPREHENSIVE ADVICE FROM THE SEALING EXPERTS Freudenberg Sealing Technologies is a supplier of high-quality sealing products and rounds off its portfolio with premium engineering services. A particular focus is on the area of radial shaft seals. The sealing of a drive shaft forms a so-called tribological system and consists of the following components: y radial shaft seal (RSS) y counter surface (GLF shaft) y fluid (lubricant) For further information, see also → chapter “Services – Design and Engineering”, page 10 and “Services – Damage Analysis”, page 16. The operating conditions of the respective application are referred to as tribological loading in relation to the tribological sys- tem. Individual loads can trigger various complex reactions. These in turn influence the functioning of the sealing system and the service life of the radial shaft seal and thus ultimately the application itself. Therefore, a good understanding of the radial shaft sealing system and its com- ponents is crucial for an optimal design of the sealing system. This knowledge forms the basis for a successful analysis of damage cases or leakages as well as the optimization of sealing systems in their application. Freudenberg Sealing Technologies’ services cover the following topics: y characterization • radial shaft seal (RSS) • RSS counter face (shaft) • lubricant (Fluid) y modeling • functional tests • simulation The individual categories are briefly de- scribed below. 13.2 CHARACTERIZATION RADIAL SHAFT SEAL (RSS) The right combination of analytical methods and holistic interpretation of the results is crucial for determining the cause of a damage case or an unsatis- factory functional test. The available analyses or methods for characterization can be divided into three groups: y morphology y chemical composition y mechanical properties CHARACTERIZATION OF MORPHOLOGY Optical microscopy With classical, optical microscopy, inter- esting areas such as e.g. the contact area of the RSS are surveyed. Measuring the area width is one of the possible options. Statements can also be made about visual changes, such as discoloration, deposits, grooving or blistering (→ Fig. 201). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 401 X E D N I

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Seals for Rotary Applications Fig. 201 RSS contact surface with bubble formation Fig. 203 µCT image of a RSS sealing lip CHARACTERIZATION OF CHEMICAL COMPOSITION Since damage to the RSS is in most cases caused by an interaction of the elastomer with a medium (lubricant, cleaning agent ...) and/or thermal overload, it is crucial to determine possible changes in the chem- ical composition of the RSS. For this purpose, various analysis methods are used, also in combination. The most important methods are the following: y Scanning electron microscopy (SEM) in combination with energy dispersive y X-ray spectroscopy (ED X) The aim is to obtain a high-resolution image of the sample using the electron microscope and, at the same time, to determine the distribution of chemical elements on or in the sample (→ Fig. 204, Fig. 205, Fig. 206). 3D images of the sealing lip are also very informative (→ Fig. 202). Fig. 202 RSS contact surface with cove formation This allows a better evaluation of the wear mechanism and the formation of deposits. Micro computed tomography (µCT) A specially developed computed tomog- raphy method is used to characterize structures below the surface, such as bubbles. The entire RSS or a section of the ring can be scanned non-destructively with this method and the formation of bubbles or cracks can be optimally eval- uated (→ Fig. 203). 402

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13. Simmerring® engineering CHARACTERIZATION OF MECHANICAL PROPERTIES The mechanical properties of the sealing edge are an important factor for the functional capability, i.e. the sealing effect of an RSS. These determine the conveying behavior and the friction. The characterization of these quantities is based on two basic principles: On the one hand, the radial force of the RSS is used. This makes it possible to as- sess a change in the mechanical proper- ties of the entire sealing lip. Secondly, it is possible and important to characterize the material directly at the sealing lip. Two approaches can be considered for this purpose: y tactile detection: the sealing lip is examined under the microscope and experienced staff evaluate any hardening or softening of the material y micromechanical analysis: the stiffness of the elastomer is deter- mined with micro-indentation. This makes it possible to perform a micro- mechanical distribution analysis. The correct combination of the methods listed and the interpretation of the results are decisive in characterizing RSS and determining the causes. Cause identifi- cation is only possible in combination with product and system know-how. Fig. 204 SEM image of a sealing lip Fig. 205 SEM image of a sealing lip Fig. 206 CU enrichment For example, the distribution of phospho- rus and copper can be used to draw conclusions about the interaction with media in contact. Other methods for determining chemical interactions: y infrared spectroscopy y gas and liquid chromatography, e.g. of extracts I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 403 X E D N I

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Seals for Rotary Applications SEAL COUNTER SURFACE In addition to the RSS itself, the shaft or seal counter surface is another important component of the tribological system (→ “8.1 Shaft design”, page 322). The quality of the macroscopic properties, such as the shaft diameter and the round- ness and hardness of the surface, are just as important for reliable sealing function as the microscopic properties, i.e. the to- pography of the mating surface. Known 2D and 3D measurement methods, e.g. according to DIN EN ISO 21920 and DIN EN ISO 25178, are used for their de- scription and evaluation. The surface parameters of waviness and roughness describe the height structure with a single integral value and are deci- sive with regard to friction, wear and lu- brication conditions of the radial shaft seal. However, these amplitude parame- ters do not contain any information on spatial, direction-dependent properties of the surface topography. Since a lead-free surface is required for reliable functioning of the radial shaft seal (→ “Checking the absence of lead in the wave,” page 130), additional spatial or structure-oriented parameters are to be used for the assessment. Lead or shaft lead generally describes sur- face structures on the RSS mating surface which are active in conveying. Depend- ing on the direction of rotation, these can lead to fluid conveyance of the fluid to be sealed. This fluid conveying effect of the surface can thus lead to leakage or insuf- ficient lubrication and thus to a signifi- cant reduction of the service life. In both cases, not only the service life of the seal- ing system is negatively affected, but also that of the end application. Consequently, seal counter surfaces must be inspected for lead. Fig. 207 Optical 3D surface measurement, “Structured Illumination Micros- copy” (SIM) y tactile and optical surface inspection (2D/3D) according to DIN, ISO and VDA y qualitative and quantitative macro- Depending on the expression of the active structures of promotion, lead can be categorized as follows: and micro-lead analysis y wear investigation y evaluation and consultation on the suitability of the RSS counter surface y micro-lead y micro-wave y macro-lead y defects 404

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13. Simmerring® engineering Macro-lead Macro-lead according to MBN 31007-7, on the other hand, describes strictly axially pe- riodic and circumferentially circulating macroscopic structures from a width of 20 μm and represents a special case of microwaviness. For this purpose, axially measured profile records are combined to a pseudo 3D topo graphy in order to determine the dominant frequencies by means of a Fourier transformation. These frequencies in turn are important for the aproximation of an approach function of harmonic co- sine functions to the lead surface. The macro-lead parameters can then be derived from the mathematically gener- ated lead function. The following investigations are suitable for this purpose: y lead test with the thread method, e.g. according to the lead test method described in Fig. 150 (→ page 327) or according to OS 1-1 of the Rubber Manufacturing Association (RMA) y micro-lead measurement according to IMA-Mikrodrall® y Macro-lead measurement according to MBN 31007-7 Thread method The thread method is a semi-quantitative method for lead testing. In general, the presence of a lead can be inferred by means of an axial movement of the thread which is dependent on the direc- tion of rotation. In addition, the evalua- tion according to OS 1-1 (RMA) also allows the calculation of a lead angle. However, the lead angle calculated in this way should not be understood as an absolute measured value. Nevertheless, the thread method has established itself over decades as a fast and cost-effective lead test and is therefore still part of the industry standard today. Micro-lead Micro-lead analysis according to IMA- Mikrodrall® is based on the statistical evaluation of stochastically distributed, anisotropic structures with a width of less than 20 µm. The structure-based evaluation method provides typical distribution curves (→ Fig. 208) and the parameters calculated from them for evaluating the mating sur- face in terms of micro-lead. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 405 X E D N I

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Seals for Rotary Applications Extracted abrasive grooves Angular distribution Fig. 208 Micro-lead measurement and evaluation according to IMA-Mikrodrall® red: right-hand lead; white: circumferential speed; blue: left-hand lead Angular orientation [°] Surface profile Lead profile Fig. 209 Macro-lead measurement and evaluation according to MBN 31007-7 406

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13. Simmerring® engineering 13.3 MODELING FUNCTIONAL TESTS ON A TEST RIG A central component in the evaluation of dynamic sealing systems consists of suit- able functional tests on dynamic test rigs. The test rigs themselves and the definition of suitable test cycles are equally crucial in order to simulate operating conditions that are as close as possible to real-life condi- tions.* Test rig investigations are carried out, for example, to assess the perfor- mance of new sealing ring designs and materials and to evaluate the compatibil- ity of lubricants and reaction with elas- tomers. The world’s largest test facility for dynam- ic sealing rings with approx. 260 test rigs (as of 2020) is located at the FST head- quarters in Weinheim. It offers state- of- the-art test stands for simulating a wide range of test conditions. * The supplier can only verify the material compatibility and function of the seal on the basis of prototypes in application-related test bench trials; the validation of the seal in the real application is ultimately the sole responsibility of the customer. Play-circle  Simmerring® Test Rig I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 210 Typical test rig for performing cycle tests 407 X E D N I

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Seals for Rotary Applications Fig. 211 Large shaft test rig for shafts < 1,000 mm DYNAMIC CYCLE TEST RIGS Cycle test rigs are capable of running through speed and temperature settings in automated test programs, such as those found in modern industrial drives or industrial robots. It is also possible to generate very high acceleration settings and to set up reversing shaft operation with alternating directions of rotation. In the most modern generations of test rigs, the frictional torque can be measured during operation. HIGH-SPEED TEST RIGS Sealing rings can be tested at maximum sliding speeds on modern high-speed test rigs. This means that demanding operat- ing conditions, such as those found in the e-mobility or power tools sector, can be mapped. In special configuration stages, the test rigs allow friction torque to be recorded during operation. PRESSURE TEST RIGS Pressure seals, such as those used in pumps or hydraulic motors in the Fluid Power sector, can be tested on appropriate test rigs under realistic pressure conditions. Speed, temperature and pressure cycles can be run automatically on the existing test rigs. DUST AND SLUDGE TEST RIGS If, for example, sealing rings are tested for suitability in agriculture or construction applications, dust and sludge exposure is an essential boundary condition. Freuden- berg Sealing Technologies has various test rigs for carrying out standardized tests with these external influences. 408

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13. Simmerring® engineering 13.4 SERVICES FST’s testing and characterization capa- bilities and the experience gained from decades of RSS development, evaluation and interpretation of test results are of- fered to FST Engineering Services custom- ers in the form of services. With inquiries for these services, please contact directly: engineering.services@fst.com Other test rigs include: y cryogenic test rigs for tests down to ‒50 °C y vibration tests with dynamically de- flected shaft y large shaft test rig for testing shafts < 1,000 mm In the USA, additional FST test centers with a wide range of testing capabilities are available. SIMULATION Thanks to the use of various simulation methods, the possible behavior of the sealing system in the intended application can be evaluated. For example, the sim- ulation of the finite element method (FEM) is used to predict the mechanical behavior of the seal. In addition, specifi- cally developed calculation and simulation methods provide answers to questions about functionally relevant parameters of the radial shaft seal. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 409 X E D N I

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Seals for Rotary Applications 14. SPECIAL SEALS 14.1 MICRO-SIMMERRING® PRODUCT ADVANTAGES y Simmerring® for shaft diameters 1–3 mm y Functionality comparable with Simmerring® of larger dimensions y Springless elastomer lip design that ensures robust and reliable func- tionality y Due to the optimal design, the Mi- cro-Simmerring® has a minimized frictional torque y Dry-running capability – up to 20 min. (depending on operating conditions, even more) y External grooving for simplified in- stallation y Adhesion negligible even under dry operating conditions y Flexible in application due to the use of various elastomer materials (EPD M, NBR, FKM, XP ...); for highest chemical resistance also possible with FFKM y Separation of different pressure levels possible y Manual installation without tools y Operating temperature depending on material from ‒40 °C to +200 °C y Shaft speed up to approx. 20,000 rpm (depending on operating conditions) Micro-Simmerring® for rotary applications with shaft diameters of 1–3 mm. Used in demanding, customer-specific miniature applications such as micropumps, micro- drives and microactuators. Freudenberg Sealing Technologies devel- ops the optimum solutions for you with individually tailored design, size and ma- terial. FEM-optimized and proven geometry without metal support part and spring together with innovative mold and process concepts with high precision and minimal injection weight enable the smallest di- mensions with minimal friction power and wear. FUNCTION AND OPERATING CONDITIONS Example of a successful test run with Micro-Simmerring®, shaft diameter = 2 mm y 5,000 hours life tests at 6,000 rpm leakage-free passed y adhesion not detectable in wet and dry start-up y frictional torque (unpressurized) ≈ 25% of typical max. drive torque of an electric micromotor y no wear on the sealing lip detectable (microscopic) y functional tests at 2.5 bar at 6,000 rpm passed 410

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14. Special seals t +0.3 0 1 Ø DH7 20° RECOMMENDATIONS INSTALLATION SPACE WAVE Tolerance Roundness Roughness Hardness Finish HOUSING BORE ISO h7 ≤ 100 μm Ra = 0.2 … 0.8 μm Rz = 1.0 … 5.0 μm Rmax ≤ 6.3 μm 45 … 60 HRC lead-free Tolerance ISO H7 Roughness, metallic adhesive seat Rz = 6.3 … 16 μm Please ask your contact person for the EIS- Sheets (Engineering Informa tion Sheets). Note: These are usually customer-specific com- ponents that are adapted to your appli- cation by the experts using the FST design guidelines. For this reason, specific clarification of all relevant framework parameters is re- quired. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 411 X E D N I

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Seals for Rotary Applications PRODUCT ADVANTAGES y Reliable sealing even with increased roughness of the bore, thermal ex- pansion and split housings y Very stable design y Paintable y Variety of standard versions APPLICATION Sealing cap for closing and static sealing of boreholes in housings with press fitting, e.g. assembly feedthroughs in gearbox housings. 14.2 SEALING CAPS GA, GSA PRODUCT DESCRIPTION Sealing caps with press fit. y GA (normal design rubber outside): sealing cap with vulcanized metal inserts made of sheet steel – standard design y GSA (special design rubber/steel out- side): sealing cap with vulcanized metal inserts made of sheet steel with metal seat – special design for increased pressing forces MATERIAL DESCRIPTION COLOR HARDNESS STIFFENING PLATE Acrylonitrile- butadiene rubber 75 NBR 99004 Black Approx. 75 Shore A Steel SPCC (similar to DC01 290) Sealing caps GA, GSA made of other materials are available upon request APPLICATION AREA PRESSURE [bar] TEMPERATURE RANGE [°C] SCOPE Max. 0.5 * –40 … +100 All common mineral oils * For higher pressures, the cap should be secured, e.g. by a retaining ring 412

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14. Special seals DESIGN INFORMATION Design of the locating bore T = H + 0.5 H 10 –20° Ø D DH8Ø Roughness of the bore type GA Rmax <= 25 µm Ra = 1.6 ... 6.3 µm Rz = 10 ... 25 µm Roughness of bore type GSA Rmax <= 16 µm Ra = 0.8 ... 3.2 µm Rz = 6.3 ... 16 µm Installation It is important to ensure correct installa- tion. Preferably, a hydraulic or mechanical press-fit device is used to press the cover into the housing bore. This grips the out- side of the cover over a large area so that the pressing force acts as close as possible to the outer diameter. Please note that the press-in tool should be held in the end position for a while so that spring back or skewing of the cap is reduced to a mini- mum. The rubber coating of the cover should always be installed beyond the bore chamfer (after installation, the cham- fer is no longer touched by the rubber). Reusability The sealing caps are not reusable and are destroyed during deinstallation. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O I T A C I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 413 X E D N I

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S E A L S F O R H Y D R A U L I C S I F L U D P O W E R A P P L I C A T I O N S – 4 1 5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING i S e a l s f o r F l u d P o w e r A p p l i c a t i o n s – H y d r a u l i c s INTRODUCTION & SERVICES

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Seals for Fluid Power Applications – Hydraulics TABLE OF CONTENTS 1. PRODUCT OVERVIEW 1.1 Rod seals 1.2 Piston seals 1.3 Symmetrical seals for rods and pistons 1.4 1.5 Wipers 1.6 Guides 1.7 Static seals Radial seals for rotary/stroke and rotary/swivel movements 2. INTRODUCTION 3. SEALS AND SEALING SYSTEMS 3.1 3.2 Classification of seals in hydraulics Basic requirements for a seal Additional requirements for the components of a sealing system Dependencies in the selection of elements for a sealing system Sealing solutions in detail Single seal vs. primary and secondary seal of a sealing system Standard sealing systems in hydraulics The sealing system for demanding applications The pressure relief function for special operating conditions Pressure deformation volume and interspace pressure 3.4 Wipers – the protective element in the sealing system 3.5 3.3 Guide elements in the hydraulic cylinder Geometrical influencing factors on the hydraulic cylinder – Ideal vs. real Selection of the guide material Laminated fabric type with special geometry – Guivex guide elements Profile thickness of the guide element 1.5 mm vs. 2.5 mm vs. 4 mm Elastic deformation of metallic components Dimensioning guide elements using different approaches for different objectives – Catalog vs. Calculation 3.6 Adjustment: ways to adjust the guide system 4. FACTORS INFLUENCING THE SEALING SYSTEM The extrusion gap Common sealing materials in hydraulics SEALING MATERIALS 5.1 5.2 PTFE compounds and polyethylene sealing materials 5.3 Polyurethane sealing materials 5.4 Elastomers 5.5 Laminated fabrics 5.6 Polyamide (filled) 5. 416 418 418 430 440 442 444 452 454 456 458 458 458 459 460 460 460 460 461 463 463 465 466 466 466 468 469 469 470 472 476 476 479 480 481 484 486 488 489

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Table of Contents I & N O T C U D O R T N S E C I V R E S I 6. 7. 8. 9. INFLUENCING FACTORS 6.1 6.2 Friction in the tribological system Basic mechanism of friction Stick-slip in the area of mixed friction Friction behavior of elastomer materials Friction behavior of thermoplastics Counter surface – part of the tribological system Surface finishing Surface assessment Evaluation of the measurement results Roughness parameters Outlook PRODUCT PRESELECTION 7.1 7.2 Product finder for sealing systems Product finder for individual components INSTALLATION OF HYDRAULIC SEALS 8.1 8.2 8.3 Optimal installation preparation Installation of the seal in an axially open housing Selection of the installation method for snap-in/-on mounting of hydraulic seals Manual installation Pliers installation Mounting strap Installation tool Deinstallation of hydraulic seals 8.4 SEAL FAILURE – PREVENTION AND DAMAGE ANALYSIS 9.1 9.2 9.3 Introduction Tools/methods of damage analysis Typical damage to seals and related causes Air in the hydraulic medium Gap extrusion Twisting Foreign bodies in the hydraulic medium Cracking Dissolution/decomposition (Hydrolysis) Heavy wear of the sealing edge Blow-by effect 10. SPECIAL SEALS Forseal FOI/FOA made of PTFE D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 490 490 491 491 492 492 493 493 496 496 497 499 501 501 506 517 517 518 520 520 520 521 522 523 524 524 524 527 527 528 529 529 529 530 530 531 533 533 417 X E D N I

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Seals for Fluid Power Applications – Hydraulics 1. PRODUCT OVERVIEW 1.1 ROD SEALS DESIGN DESCRIPTION MAIN APPLICATIONS T20 Single-acting U-ring for universal use in many appli- cations LF300 Single-acting U-ring opti- mized in terms of friction, stick-slip and hydrodynamic pump-back capacity Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; injection molding machines; support cylinders Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; injection molding machines Syprim SM Single-acting U-ring with an integrated back-up ring and pressure relief function Earthmoving equipment; fork lifts; agricultural machin- ery; truck-mounted cranes; injection molding machines NI300 Single-acting U-ring with an additional support bead Earthmoving equipment; presses; support cylinders Merkel® TM20 Single-acting U-ring with an asymmetric profile Machined version of type T20 for large diameters in heavy industry applications T22 Single-acting U-ring with an additional support bead Earthmoving equipment; support cylinders; ship hydraulics; mobile hydraulics T23 Single-acting U-ring with an integrated back-up ring Earthmoving equipment; hydraulic steel structures; support cylinders; ship hydraulics; heavy mobile hydraulics; scrap shears PRODUCT GROUP U-rings 418

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 94 AU V142 ‒30 … +110 94 AU 30000 ‒35 … +120 94 AU 925 ‒30 … +110 Yes Yes Further information on our product portfolio 92 AU 21100 ‒50 … +110 Yes Yes 94 AU 30000 ‒35 … +120 95 AU V142/POM ‒30 … +110 94 AU 30000/POM ‒35 … +120 94 AU 925 ‒30 … +110 94 AU 30000 ‒35 … +120 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 Yes Yes Yes Yes Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B 95 AU 142 ‒30 … +110 Yes Yes 95 AU 142/POM ‒30 … +110 Yes Yes S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 419 X E D N I

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Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS PRODUCT GROUP U-rings T24 Single-acting U-ring with an additional support bead Telescopic cylinders HDR-2C Single-acting, 2-component U-ring for high-pressure applications Earthmoving equipment; fork lifts; tail lifts; truck-mounted cranes; support cylinders Merkel® NRS-0503 Single-acting U-ring with an asymmetric profile and an in- tegrated POM or PA back-up ring Single seal for the spare parts market in heavy industry; especially well suited for large diameters and for bridging large extrusion gaps Merkel® L20 Single-acting U-ring with an asymmetric profile NI150 Single-acting U-ring, universal use NI250 Single-acting U-ring with an integrated back-up ring NI400 Single-acting U-ring with integrated back-up ring and fabric reinforcement on the support part Industrial presses and large cylinders; especially for water and water emulsion as oper- ating media (NBR) Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 and LF300 Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 and LF300 Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20, LF300 and HDR-2C 420

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 95 AU 142 ‒30 … +110 Yes Yes 92 AU 21100 ‒50 … +110 98 AU 928 ‒50 … +110 95 AU 142/POM, PA ‒30 … +110 93 AU V167/POM, PA ‒20 … +110 85 NBR B203 ‒30 … +100 85 FKM K664 ‒10 … +200 Yes No Yes Yes No Yes 80 NBR 878 ‒30 … +100 Yes Yes 80 NBR 878/POM ‒30 … +100 Yes Yes 80 NBR 878/POM ‒30 … +100 Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 421 X E D N I

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Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS Merkel® NRS-0214 Single-acting U-ring with an integrated POM or PA back- up ring and fabric reinforce- ment on the sealing lip Merkel® NRS-0216 Single-acting U-ring with an integrated POM or PA back-up ring and fabric reinforcement on the support part Metallurgical industry; presses; ship hydraulics; scrap shears; special cylinders; injection molding machines; hydraulic steel structures Metallurgical industry; presses; ship hydraulics; scrap shears; special cylinders; injection molding machines; hydraulic steel structures H MF Single-acting lip seal with a preload spring on the sealing lip Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 and, LF300 H OF Single acting lip seal without a preload spring Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 and, LF300 FOI Single-acting PTFE U-ring with a metallic tension spring – can be used in axially open O-ring installation spaces Hot water valves; hydraulic and pneumatic cylinders OMS-MR Single-acting compact seal – standard version Mobile hydraulics; injection molding machines; industrial presses PRODUCT GROUP U-rings Compact seals Merkel® Omegat 422

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 80 NBR B246/ BI-NBR B4 B248/ POM; PA 80 NBR B246/ BI-NBR B4 B248/ POM; PA ‒30 … +100 Yes ‒30 … +100 Yes No No 88 NBR 101 ‒30 … +100 Yes Yes 88 NBR 101 ‒30 … +100 Yes Yes PTFE F56110/ stainless steel 1.4310 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒200 … +260 Yes Yes ‒30 … +100 ‒10 … +200 Yes Yes PE E083/NBR ‒30 … +80 R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 423 X E D N I

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Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS OMS-MR PR Single-acting compact seal with pressure relief function Mobile hydraulics; injection molding machines; industrial presses OMS-MR DW Compact seal for pressuriza- tion on both sides – special design Mobile hydraulics; hand-held equipment; injection molding machines; industrial presses OMS-S Single-acting, heavy-duty compact seal – standard version Hydraulic steel structures; steel mills; industrial presses OMS-S PR Single-acting, heavy-duty compact seal with pressure relief function and support skids Hydraulic steel structures; steel mills; industrial presses OMS-S SR Single acting, heavy-duty compact seal with support skids Hydraulic steel structures; steel mills; industrial presses OMSU-MR Single-acting compact seal – standard version Injection molding machines; support cylinders PRODUCT GROUP Compact seals Merkel® Omegat 424

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 98 AU V211/NBR ‒30 … +100 98 AU 21440/NBR ‒20 … +100 Yes Yes No Yes Yes Yes No Yes Yes Yes Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 425 X E D N I

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Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS OMSU-MR PR Single-acting compact seal with pressure relief function Injection molding machines (injection unit); support cyl- inders KI310 Single-acting compact seal – standard version Mobile hydraulics; telescopic cylinders KI320 Single-acting compact seal with integrated back-up ring and additional support bead Mobile hydraulics; support cylinders; industrial presses Merkel® S8 Single-acting compact seal with rubber/fabric retaining part TFMI Compact seal for pressuriza- tion on both sides Mainly for meeting spare parts requirements. For new constructions, FST recommends series such as T20 Mainly for meeting spare parts requirements. For new constructions, FST recommends series such as Omegat OMS-MR DW ES, ESV Single-acting multi-compo- nent compact seal Hydraulic steel structures; steel mills; industrial presses; scrap shears ES61 Single-acting multi-compo- nent compact seal with PTFE thrust ring Hydraulic steel structures; steel mills; industrial presses; scrap shears PRODUCT GROUP Compact seals Merkel® Omegat Compact seals Compact seals Merkel® V-Packs and V-Packing Sets 426

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 98 AU V211/NBR ‒30 … +100 98 AU 21440/NBR ‒20 … +100 No Yes 94 AU 925 ‒30 … +110 Yes Yes 94 AU 925/POM ‒30 … +110 Yes Yes 70 NBR B209 ‒30 … +100 Yes No PTFE 177023/NBR ‒30 … +100 Yes Yes NBR fabric/NBR ‒30 … +100 FKM fabric/FKM ‒15 … +140 Yes PTFE B570/ NBR fabric/NBR ‒30 … +100 Yes No No R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 427 X E D N I

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Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS ES81 Single-acting multi-compo- nent compact seal with PU thrust ring Hydraulic steel structures; steel mills; industrial presses; scrap shears VPS40 Single-acting, three-piece compact seal – new develop- ment for large diameters and heavy-duty applications New development as a replacement for V-Packs and V-Packing Sets DMS0180 Single-acting multi-compo- nent compact seal in PE design with NBR back-up ring For harsh operating conditions, e.g. offshore in conjunction with ceramic counter surfaces, etc. V1000 Single-acting multi-compo- nent compact seal for heavy-duty applications Forging presses; manipulators; scrap shears TFW Single-acting multi-compo- nent compact seal with PTFE sleeves Axially moving fittings spindles; rods and plungers; slow rotating shafts Vocomatic Patented storage element for drag oil compensation of rod sealing systems Long-stroke cylinders with widely varying cylinder re- traction and extension speeds PRODUCT GROUP Compact seals Merkel® V-Packs and V-Packing Sets 428

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 93 AU V167/ NBR fabric/NBR ‒30 … +100 Yes No 93 AU V167/NBR ‒20 … +100 Yes Yes PE E083/NBR ‒30 … +80 BI-NR B6B210 ‒30 … +100 No No Yes No PTFE F52902 ‒200 … +220 Yes Yes 70 VQM 10801/POM ‒30 … +100 No No R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 429 X E D N I

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Seals for Fluid Power Applications – Hydraulics 1.2 PISTON SEALS DESIGN DESCRIPTION MAIN APPLICATIONS PRODUCT GROUP U-rings NA300 Single-acting U-ring NA150 Single-acting U-ring NA250 Single-acting U-ring with integrated back-up ring Earthmoving equipment; mobile hydraulics; industrial presses Mainly for meeting spare parts requirements. For new constructions, FST recommends series such as NA300 or T18 Mainly for meeting spare parts requirements. For new constructions, FST recommends series such as NA300 or T18 NA400 Single-acting U-ring with integrated back-up ring and fabric reinforcement on sealing lip Mainly for meeting spare parts requirements. For new constructions, FST recommends series such as NA300 or T18 T18 Single-acting U-ring with integrated back-up ring and pressure relief grooves Earthmoving equipment; mobile hydraulics; industrial presses Merkel® TM21 Single-acting U-ring with asymmetric profile Heavy-duty applications, e.g. industrial presses; large cylin- ders Merkel® NRS-0215 Single-acting U-ring with in- tegrated POM or PA back-up ring and fabric reinforcement on the entire sealing lip Heavy-duty applications with special requirements. Mainly used in large cylinders, e.g. in industrial presses 430

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 94 AU 925 ‒30 … +110 94 AU 30000 ‒35 … +120 Yes Yes 80 NBR 878 ‒30 … +100 Yes Yes 80 NBR 878/POM ‒30 … +100 Yes Yes 80 NBR 878/POM ‒30 … +100 Yes Yes 95 AU 142/POM ‒30 … +110 Yes Yes 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 No Yes 80 NBR B246/ BI-NBR B4 B248/ POM; PA ‒30 … +100 Yes No R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 431 X E D N I

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Seals for Fluid Power Applications – Hydraulics PRODUCT GROUP U-rings DESIGN DESCRIPTION MAIN APPLICATIONS Merkel® NRS-0217 Single-acting U-ring with in- tegrated POM or PA back-up ring and fabric reinforcement on parts of the sealing lip Heavy-duty applications with special requirements, mainly used in large cylinders, e.g. in industrial presses Merkel® NRS-0504 Single-acting U-ring with asymmetric profile and POM or PA back-up ring Heavy-duty applications with focus on large cylinders FOA Single-acting PTFE U-ring with metallic tension spring – for use in axially open O-ring installation spaces Hot water valves; hydraulic and pneumatic cylinders Single-acting compact seals Merkel® Omegat OMK-E Single-acting compact seal – special design Mobile hydraulics; hand-held equipment; injection molding machines; industrial presses OMK-E PR Single-acting compact seal with pressure relief function Mobile hydraulics; injection molding machines; industrial presses OMK-ES Single-acting, heavy-duty compact seal – special design OMK-ES PR Single-acting, heavy-duty compact seal with pressure relief function Manipulators; industrial presses; ship hydraulics; injection molding machines; hydraulic steel structures; rolling mills Manipulators; industrial presses; ship hydraulics; injection molding machines; hydraulic steel structures; rolling mills 432

433

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 80 NBR B246/ BI-NBR B4 B248/ POM; PA ‒30 … +100 Yes No 95 AU 142/POM; PA ‒30 … +110 93 AU V167/POM; PA ‒20 … +110 Yes Yes PTFE F56110/ rostfreier Stahl 1.4310 ‒200 … +260 Yes Yes PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 No No No No Yes Yes Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 433 X E D N I

434

Seals for Fluid Power Applications – Hydraulics PRODUCT GROUP Single-acting compact seals Merkel® Omegat Single-acting compact seals DESIGN DESCRIPTION MAIN APPLICATIONS OMKU-E Single-acting compact seal – special design Handling equipment; injection molding machines; control and regulating equipment Merkel® EK, EKV Single-acting, multi-part compact seal T with spring Lip seal with spring on the sealing lip and a flange for axial fixing Iron and steel industry; indus- trial presses; ship hydraulics; scrap shears; special cylinders; injection molding machines; hydraulic steel structures Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as NA300 T without spring Lip seal with flange for axial fixing – standard version without spring on sealing lip Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as NA300 Double-acting compact seals Merkel® Omegat OMK-PU Compact seal for pressuriza- tion on both sides – standard version OMK-MR Compact seal for pressuriza- tion on both sides – standard version Forklift trucks; agricultural machinery; truck-mounted cranes; mobile hydraulics; material handling; standard cylinders Fork lifts; handling equipment; agricultural machinery; truck-mounted cranes; presses; ship hydraulics; injection mold- ing machines; control and regu- lating equipment; rolling mills OMKU-MR Compact seal for pressuriza- tion on both sides – standard version Handling equipment; injection molding machines; control and regulating equipment 434

435

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 98 AU V211/NBR ‒30 … +100 98 AU 21440/NBR ‒20 … +100 NBR fabric/NBR ‒30 … +100 FKM fabric/FKM ‒15 … +140 No Yes Yes No 88 NBR 101 ‒30 … +100 Yes Yes 88 NBR 101 ‒30 … +100 95 AU V142/NBR ‒30 … +100 98 AU 30500/NBR ‒30 … +100 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E083/NBR ‒30 … +80 98 AU V211/NBR ‒30 … +100 98 AU 21440/NBR ‒20 … +100 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 435 X E D N I

436

Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS OMK-S Compact seal for pressuriza- tion on both sides – standard version for heavy-duty appli- cations Simko 300 Compact seal for pressuriza- tion on both sides – standard version HDP 330 Compact seal for pressuriza- tion on both sides – PA GF slide ring with step cut Large cylinders; manipulators; industrial presses; ship hy- draulics; injection molding machines; hydraulic steel structures; rolling mills Earthmoving equipment; mobile hydraulics; tail lifts; agricultural machinery; truck-mounted cranes; injection molding machines; support cylinders Earthmoving equipment; agricultural machinery; heavy- duty applications; cylinders with ready-drawn surfaces Simko 320X2 Compact seal for pressuriza- tion on both sides with fabric reinforcement and two angu- lar back-up rings Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as Simko 300 Simko 520 Compact seal for pressuriza- tion on both sides with fabric reinforcement and two inte- grated back-up rings Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as HDP 330 Merkel® L27 Compact seal for pressuriza- tion on both sides with two integrated back rings and an elastomeric preloading el- ement Excavators; earthmoving equipment; industrial presses; heavy industry L43 Compact seal for pressuriza- tion on both sides with two back-up rings and two angular back-up rings Earthmoving equipment; agricultural machinery; truck-mounted cranes; standard cylinders PRODUCT GROUP Double-acting compact seals Merkel® Omegat Double-acting compact seals 436

437

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 Yes Yes PE E083/NBR ‒30 … +80 98 AU 928/NBR ‒30 … +100 Yes Yes PA 4112/NBR ‒30 … +100 Yes Yes 80 NBR 878/PA ‒30 … +100 Yes Yes 80 NBR 878/POM ‒30 … +100 Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B PTFE B602/NBR/POM ‒30 … +100 Yes Yes 80 NBR B281/TPE/PA ‒30 … +100 Yes Yes S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 437 X E D N I

438

Seals for Fluid Power Applications – Hydraulics PRODUCT GROUP Double-acting compact seals DESIGN DESCRIPTION MAIN APPLICATIONS T19 Compact seal for pressuriza- tion on both sides with two angular back-up rings Agricultural machinery; standard cylinder Merkel® T42 Compact seal for pressuriza- tion on both sides with two back-up rings Mining Merkel® T44 Compact seal for pressuriza- tion from both sides with semi-activated back-up rings Mining TFMA Compact seal for pressuriza- tion on both sides Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as Omegat OMK-MR TDUOH Compact seal for pressuriza- tion on both sides – standard version Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as Simko 300 438

439

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 95 AU 142/POM ‒30 … +110 Yes Yes 93 AU V167/NBR/POM +5 … +60 93 AU V167/NBR/POM +5 … +60 No No Yes Yes PTFE 177023/NBR ‒30 … +100 Yes Yes 88 NBR 101/Stahl ‒30 … +100 Yes No R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 439 X E D N I

440

Seals for Fluid Power Applications – Hydraulics 1.3 SYMMETRICAL SEALS FOR RODS AND PISTONS PRODUCT GROUP U-rings DESIGN DESCRIPTION MAIN APPLICATIONS N Single-acting U-ring, universal use AUN Single-acting U-ring, universal use N100 Single-acting U-ring, universal use AUN100 Single-acting U-ring, universal use Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 (rod seal) or NA300 (piston seal) Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 (rod seal) or NA300 (piston seal) Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 (rod seal) or NA300 (piston seal) Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as T20 (rod seal) or NA300 (piston seal) 440

441

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 90 NBR 109 ‒30 … +100 Yes Yes 94 AU 925 ‒30 … +110 Yes Yes 90 NBR 109 ‒30 … +100 Yes Yes 94 AU 925 ‒30 … +110 Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 441 X E D N I

442

Seals for Fluid Power Applications – Hydraulics 1.4 RADIAL SEALS FOR ROTARY/STROKE AND ROTARY/SWIVEL MOVEMENTS DESIGN DESCRIPTION MAIN APPLICATIONS OMS-DH Single-acting compact seal with contoured PTFE profile ring and pressure activation grooves Injection molding machines (injection unit); rotary drives OMS-DR HB Single-acting compact seal with retaining flange for combined rotary/swivel movements Injection molding machines (injection unit); rotary drives OMK-DR HB Compact seal for pressuriza- tion on both sides with a PTFE slide ring in the groove base For combined lifting and rotary/ swivel movements M15 M16 M17 M19 Compact seal for pressuriza- tion on both sides – internal sealing Excavators; rotary feed- throughs; grabs Compact seal for pressuriza- tion on both sides – external sealing Excavators; rotary feed- throughs; grabs Compact seal for pressuriza- tion on both sides with lubri- cation groove on the running surface Excavators; rotary feed- throughs; grabs Compact seal for pressuriza- tion on both sides with fabric reinforcement on the running surface Excavators; rotary feed- throughs; grabs PRODUCT GROUP Merkel® Omegat Merkel® Rotomatic 442

443

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A PTFE GM201/FKM ‒10 … +200 PTFE C104/FKM ‒10 … +200 PTFE C104/FKM ‒10 … +200 PTFE GM201/ PTFE V039/FKM ‒10 … +200 PTFE GM201; C104/NBR ‒30 … +100 PTFE GM201; C104/FKM ‒10 … +200 PTFE GM201; C104/NBR ‒30 … +100 PTFE GM201; C104/FKM ‒10 … +200 80 NBR B246/ NBR fabric ‒30 … +80 80 NBR B246/ NBR fabric/POM ‒30 … +80 No No No Yes Yes Yes Yes Yes Yes Yes No No No No R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 443 X E D N I

444

Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS AS Wiper with metal cage and protruding wiper lip ASOB Wiper with protruding wiper lip without metal cage AU PS Wiper with metal cage and a wiper lip terminating with the housing Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as AU AS(R) Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as PU5 Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; pivot pin sealing; support cylinders AU AS Wiper with metal cage. The protruding wiper lip has a sharply machined sealing edge Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; support cylinders AU ASR Wiper with metal cage. The protruding wiper lip has a rounded sealing edge Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; support cylinders AU ASOB Wiper without metal cage re- inforcement, with protruding wiper lip and bottom-side support against tilting Mainly for meeting spare parts requirements. For new con- structions, FST recommends series such as PU5 Merkel® P6 Wiper without metal cage with protruding wiper lip and bottom-side support against tilting Industrial presses; hydraulic steel structures; rolling mills 1.5 WIPERS PRODUCT GROUP Single acting wipers 444

445

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 88 NBR 101 88 NBR 99035 ‒30 … +100 Yes No 88 NBR 101 ‒30 … +100 Yes Yes 94 AU 925 ‒30 … +110 Yes 94 AU 925 ‒30 … +110 Yes 94 AU 925 ‒30 … +110 Yes No No No 94 AU 925 ‒30 … +110 Yes Yes 85 NBR B247 ‒30 … +100 85 FKM K664 ‒10 … +200 No Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 445 X E D N I

446

Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS Merkel® PU5 Wiper with additional static sealing lip and support elements to prevent tilting Merkel® PU6 Wiper with additional static sealing lip and support elements to prevent tilting Mining; earthmoving equip- ment; fork lifts; tail lifts; agricul- tural machinery; truck-mounted cranes; industrial presses; injec- tion molding machines; support cylinders; telescopic cylinders Mining; earthmoving equip- ment; industrial presses; injection molding machines; support cylinders Merkel® PH6 Wiper with additional static sealing lip and support elements to prevent tilting Mining Merkel® PU12 DMRW2 External sealing wiper with protruding wiper lip and sup- port segments to prevent rota- tion as well as a static sealing edge to the groove base Wiper with the function of a U-ring on the inside and wiping effect on the outside. With protruding wiper lip, metal cage and additional integrated pressure relief function Mining; earthmoving equip- ment; industrial presses; injection molding machines; support cylinders Earthmoving equipment; commercial vehicles; tail lifts; agricultural machinery; truck-mounted cranes; support cylinders; industrial presses Merkel® P8 Wiper with the functionality of a U-ring inwards and wiping effect outwards Fork lifts; industrial presses; injection molding machines Merkel® P9 Wiper especially for large di- ameters with the functional- ity of a U-ring inwards and wiping effect outwards Mobile hydraulics; injection molding machines; industrial presses; large standard cylin- ders PRODUCT GROUP Single acting wipers Double wipers 446

447

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 95 AU V149 ‒30 … +110 Yes Yes 95 AV V142 ‒30 … +110 95 AU V149 ‒30 … +110 Yes Yes 93 AU V167 ‒20 … +110 97 TPE TP106 ‒30 … +110 97 TPE TP107 ‒30 … +110 95 AU V142 ‒30 … +110 95 AU V149 ‒30 … +110 93 AU V167 ‒20 … +110 No No Yes Yes 94 AU 30000 ‒35 … +120 Yes No 85 NBR B247 ‒30 … +100 90 NBR B283 ‒30 … +100 Yes Yes 85 NBR B247 ‒30 … +100 Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 447 X E D N I

448

Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS PRW1 Dust Wiper effect outwards, acting as a U-ring inwards, combining an integrated pressure relief function Material handling; fork lifts; tail lifts; agricultural machin- ery; truck-mounted cranes; support cylinders Merkel® PT1 Wiper consisting of a PTFE profile ring with sealing and wiper edge and two O-rings as preloading element Forklift trucks; large cylinders; handling equipment; agricul- tural machinery; industrial presses; injection molding machines; control equipment; rolling mills Merkel® PT1-DR HB Wiper consisting of a PTFE profile ring with sealing and wiper edge and two O-rings as preloading element. For combined rotary-stroke movements Forklift trucks; large cylinders; handling equipment; agricul- tural machinery; industrial presses; injection molding machines; control equipment; rolling mills Merkel® PT2 Wiper consisting of a PTFE profile ring with sealing and wiper edge and two O-rings as preloading element Industrial presses; injection molding machines; hydraulic steel structures; rolling mills Merkel® PT2 PR Wiper consisting of a PTFE profile ring with sealing and wiper edge and two O-rings as preloading element. Pressure relief at the sealing edge Industrial presses; injection molding machines; hydraulic steel structures; rolling mills Merkel® PT3 Wiper consisting of a PTFE profile ring with sealing and wiper edge as well as two O-rings as preloading element – externally sealing Industrial presses; injection molding machines; hydraulic steel structures; rolling mills PRODUCT GROUP Double wipers 448

449

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 94 AU 925 ‒30 … +110 92 AU 21100 ‒50 … +110 Yes Yes 94 AU 30000 ‒35 … +120 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E084/NBR ‒30 … +80 Yes Yes PTFE GM201; C104/FKM ‒10 … +200 No Yes PTFE B602; GM201/ NBR ‒30 … +100 PTFE B602/FKM ‒10 … +200 Yes Yes PE E084/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E084/NBR ‒30 … +80 PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 ‒10 … +200 PE E084/NBR ‒30 … +80 No Yes No Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 449 X E D N I

450

Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS PRODUCT GROUP Double wipers Merkel® PT4 Wiper consisting of a PTFE profile ring with seal and wiper edge and an O-ring as preloading element Industrial presses; injection molding machines; hydraulic steel structures; rolling mills Merkel® PU1 Wiper consisting of a PU pro- file ring with seal and wiper edge and two O-rings as preloading element Industrial presses; injection molding machines; rolling mills PU11 Wiper with the functionality of a U-ring inwards and wiping effect outwards Forklift trucks; injection molding machines; standard cylinders 450

451

1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A PTFE B602; GM201; C104/NBR PTFE B602; GM201; C104/FKM ‒30 … +100 R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H ‒10 … +200 Yes Yes PE E084/NBR ‒30 … +80 98 AU V211/NBR ‒30 … +100 98 AU 21440/NBR ‒20 … +100 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 No Yes Yes Yes R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 451 X E D N I

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Seals for Fluid Power Applications – Hydraulics DESIGN DESCRIPTION MAIN APPLICATIONS FRI Standard guide element made of fiber reinforced polyamide Material handling; fork lifts; agricultural machinery; truck-mounted cranes Guivex SBK Patented guide element made of laminated fabric. Optimized stress distribution due to profiled geometry to the groove base SB Standard guide element made of laminated fabric FRA Standard guide element made of fiber reinforced polyamide Guivex KBK Patented guide element made of laminated fabric. Optimized stress distribution due to profiled geometry to the groove base KB Standard guide element made of laminated fabric Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; industrial presses; injection mold- ing machines; hydraulic steel structures; support cylinders Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; industrial presses; injection mold- ing machines; hydraulic steel structures; support cylinders Earthmoving equipment; ground support equipment; agricultural machinery; truck-mounted cranes Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; industrial presses; injection mold- ing machines; hydraulic steel structures; support cylinders Earthmoving equipment; fork lifts; tail lifts; agricultural machinery; truck-mounted cranes; industrial presses; injection mold- ing machines; hydraulic steel structures; support cylinders SF; KF Standard PTFE guide element by the meter or cut to size Handling equipment; control/ regulation equipment; pneu- matic cylinders 1.6 GUIDES PRODUCT GROUP Rod guides Piston guides Rod/piston guides 452

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A PA 4112 ‒30 … +110 Yes Yes HG517 ‒40 … +100 HG650 HG517 HG600 HG650 ‒40 … +120 ‒40 … +100 ‒70 … +100 ‒40 … +120 Yes Yes Yes Yes PA 4112 ‒30 … +110 Yes Yes HG517 ‒40 … +100 HG650 HG517 HG600 HG650 ‒40 … +120 ‒40 … +100 ‒70 … +100 ‒40 … +120 Yes Yes Yes Yes PTFE B500 ‒30 … +100 Yes Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 453 X E D N I

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Seals for Fluid Power Applications – Hydraulics 1.7 STATIC SEALS PRODUCT GROUP Cover/ toggle- lever seals DESIGN DESCRIPTION MAIN APPLICATIONS Cover Seal PU82 One-piece, double-acting compact seal for static sealing – rod type Mobile cranes; construction machinery; fork lifts; forestry machinery; injection molding machines Cover Seal PU83 One-piece, double-acting compact seal for static sealing – piston type Mobile cranes; construction machinery; fork lifts; forestry machinery; injection molding machines Merkel® Stircomatic SRC One-piece compact seal for static sealing – axial sealing Hydraulic hammers; hydraulic control devices Merkel® Pinmatic One-piece, double-acting compact seal for combined static and swivel sealing – rod type Toggle levers; bearings and link pins; injection molding machines 454

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1. Product Overview I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® R O F S L A E S Y R A T O R S N O T A C I I L P P A 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 Yes Yes Yes Yes Yes Yes 95 AU V142 ‒30 … +110 No Yes R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 455 X E D N I

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Seals for Fluid Power Applications – Hydraulics 2. INTRODUCTION Even with the increasing electrification of many applications, high power density with low space requirements is a key dis- cipline of hydraulic cylinders. Oil hydraulics are predominantly used here, because the pressurized fluid generates enormous force with simultaneously low compress- ibility. To ensure that the pressure medium remains in the cylinder, piston and rod seals, among other things, perform both static and dynamic sealing tasks, with the sealing edges in contact with the transla- tional, usually metallic, bearing surface re- ceiving the greatest attention (→ Fig. 212). This diversity is also reflected in the re- quirements placed on the sealing elements and sealing systems used. In addition to the actual working pressure, a large num- ber of external factors have a significant influence on the selection of a suitable sealing system, including y temperature extremes y operation in heavily polluted environ- ments y high lateral forces and pressure peaks y stroke length/number of strokes per time unit From lightweight lifting cylinders in hand-held equipment, to heavy-duty construction machinery cylinders, to high- frequency controlled HAGC cylinders in steel mills, or the powerful hydraulic cylinders in large industrial presses, the applications of hydraulics are diverse. For these often complex sealing tasks, Freudenberg Sealing Technologies (here- inafter also abbreviated FST) offers a wide standard range of hydraulic seals and has developed an equally wide range of cus- tomer-specific system solutions over the past decades. Guides Primary seal (rod) Secondary seal (rod) Wiper Guides Piston seal Static seals Fig. 212 Sealing and guiding elements of a hydraulic cylinder 456

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2. Introduction This has resulted in an enormous wealth of experience, which Freudenberg Seal- ing Technologies directly shares with its customers in the form of: y application advice y detailed installation suggestions y evaluations in FST test centers and laboratories y quality products This chapter of the Technical Manual ex- plains hydraulic seals and sealing systems, including: y principles of function and action y influencing parameters y sealing materials y seal installation This chapter also covers what to do if a desired result, such as leak-free operation of a seal, is not achieved. The Freudenberg Sealing Technologies website provides more information, in- cluding extensive information/downloads on the individual products, installation instructions and videos, services and in- teresting facts about the various markets and the world of Freudenberg. The product catalog is integrated into the website for quick access to the desired product. FST Website Dynamic Seals The product overview starting on page 418 provides orientation and an initial selection aid. Product catalog Hydraulic Selector I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 457 X E D N I

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Seals for Fluid Power Applications – Hydraulics 3. SEALS AND SEALING SYSTEMS 3.1 CLASSIFICATION OF SEALS IN HYDRAULICS Different requirements and operating parameters in numerous applications have led to the development of different seal designs. A general classification of seals with regard to their function and design, with a focus on hydraulics, is shown in → Fig. 213. THE THREE FUNCTIONAL MECHANISMS OF A SEAL y Contact pressure between the seal- ing element and the counter surface required for the sealing effect y Resistance to media and no perme- ation of the medium to be sealed by the sealing material y Complete pressure reduction of the operating pressure in the contact area of the sealing lip to the counter surface to ambient level as a pre- requisite for the medium to remain in the working chamber BASIC REQUIREMENTS FOR A SEAL The task of a seal or sealing system is to keep the hydraulic medium safely within the hydraulic system. Three key statements can be derived directly from this: y the seal or sealing system must be suit- able for maintaining the operating pres- sure while the counter surface is in mo- tion y the oil film discharged to the outside on the piston rod of a hydraulic cylinder should be completely transported back into the hydraulic system during each cycle y a seal or sealing system is said to be leaking if hydraulic medium becomes visible to the outside in the form of dripping leakage. One kind of possible leakage results from the difference in the lubricant film height on the rod surface during the forward and return stroke, e.g. at high extension and low retraction speed S L A E S CONTACT NON-CONTACT DYNAMIC STATIC RECIPROCATING ROTATION INSIDE SEALING OUTSIDE SEALING Fig. 213 Classification of seals according to function and design 458

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3. Seals and Sealing Systems ADDITIONAL REQUIREMENTS FOR THE COMPONENTS OF A SEALING SYSTEM In addition to seals, a hydraulic cylinder also requires guide elements and wipers to protect the system from contamination. The properties of the individual elements are matched to the specific operating conditions. To ensure optimum interaction of the components, they are generally not used individually but preferably in combi- nation as a sealing system (→ Fig. 214). MAIN REQUIREMENTS FOR A SEALING SYSTEM y Sealing y Guiding y Protecting Rod sealing system Piston sealing system Wiper Secondary seal (rod) Rod guide Primary seal (rod) Static seal Piston guide Piston seal Static seal Fig. 214 Seals and guides of a rod and piston sealing system inside a hydraulic cylinder in contact with the counter surface I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 459 X E D N I

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Seals for Fluid Power Applications – Hydraulics DEPENDENCIES IN THE SELECTION OF ELEMENTS FOR A SEALING SYSTEM Depending on the task, different influenc- ing factors must be taken into account (→ Fig. 215). Some of these factors can only be influenced indirectly by the seal man- ufacturer, e.g. by issuing recommenda- tions. Ultimately, the functionality and performance of a sealing system must al- ways be seen in the context of all factors. A more detailed look at these influencing factors follows later in this chapter (→ “7. Product Preselection”, page 501). 3.2 SEALING SOLUTIONS IN DETAIL SINGLE SEAL VS. PRIMARY AND SECONDARY SEAL OF A SEALING SYSTEM Sealing systems can be adapted and op- timized to specific boundary conditions and requirements by varying the sealing materials and selecting a suitable sealing geometry. The division of tasks within the sealing system and the extended use of sealing elements allow even the most demanding applications to be reliably sealed. Thus, a standard sealing system usually manag- es with a single main seal, while a high-performance sealing system often works with a double assembly, i.e. a pri- mary and secondary seal. STANDARD SEALING SYSTEMS IN HYDRAULICS A typical standard sealing system for rod and piston from the diverse Freudenberg range is shown in → Fig. 216. In the pressure range up to 25 MPa, at standard stroke speeds of 0.5 m/s and operating temperatures up to +80 °C, the sealing material polyurethane is used here as standard. The standard sealing system is essential- ly based on a main seal which performs the complete sealing function. Due to the very good sealing effect, the T20 or LF300 U-rings, for example, can be used for this task. By using a double wiper, e.g. a PRW1, which in addition to the wiper lip is equipped with an additional sealing edge and an integrated pressure relief function, the functional reliability can be improved if required. Load/guiding force Guide play Assembly 3D animation hydraulics Operating conditions Medium Counter surface Seal material Environment Installation space Assembly Fig. 215 Elements of a sealing system and their influencing factors 460

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3. Seals and Sealing Systems Typical application: y Pressure: < 25 MPa y Speed: < 0.5 m/s y Temperature: ‒30 °C to +80 °C y Medium: Hydraulic oils HL, HLP Double wiper U-ring PRW1 T20 or LF300 Guide ring SB or FRI Cover Seal Guide ring KB or FRA Simko 300 Cover Seal Fig. 216 A typical rod/piston sealing system with dual function of the wiper for standard applications Map-marker-edit Choice of seal and guide according to requirements of the application If the loads are moderate, low-cost poly- amide guide rings, e.g. the FRI and FRA designs, are preferred, especially in mo- bile hydraulics. For higher system forces, guide rings of the SB, SBK and KB, KBK types made of laminated fabric are used. With increasing operating pressure, the thermal and mechanical load on the seal also rises. This influence is amplified by a high coefficient of friction of the seal ma- terial. Thus, at higher operating pressure or generally more demanding operating conditions, the appropriate type of seal and the selection of the seal material is of particular importance. THE SEALING SYSTEM FOR DEMANDING APPLICATIONS When pressure, temperature and speed increase in an application, the elements of a sealing system must be adapted to these higher requirements. In a high- performance sealing system with several sealing elements, a two-component compact seal with a sliding ring made of friction- optimized PTFE compound of the Omegat design or a polyurethane seal, such as the Syprim SM design, is used as the primary seal (→ Fig. 217). Reliably maintaining high operating pressure is the core discipline here. However, the remaining oil film on the extending rod is comparatively pronounced in seals of this type. It ensures effective lubrication of the secondary seal. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 461 X E D N I

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Seals for Fluid Power Applications – Hydraulics The somewhat thicker oil film is inherent in seals made of PTFE, while a seal made of polyurethane must be specifically designed to leave a very thin oil film on the rod. For this reason, a polyurethane sealing element is predominantly used as a secondary seal- ing element, which further reduces the oil film in order to avoid dripping leakage in front of the wiper edge (→ Fig. 218). The secondary seal is subjected to the lower interspace pressure (< 5 MPa). The main requirement is therefore to effec- tively reduce the residual oil film released via the primary seal while maintaining favorable friction values in the low-pres- sure range. Here, the LF300 or T20 poly- urethane U-rings are ideally used. Compared with the standard sealing system, the individual elements of the high-performance sealing system are used according to their functional strengths. The aim is to reliably master even demanding operating conditions. The pressurized operating medium is usually present on both sides of the pis- ton-side seal. This leads to optimum wet- ting of the seal and thus to a low coeffi- cient of friction. A slight transfer of hydraulic medium into the other pressure chamber is not perceived as leakage. Pis- ton-side sealing systems consisting of several seals are therefore reserved for special applications. Due to its importance for the function of the sealing system, a separate chapter is dedicated to the topic of “Materials” in this manual (→ chapter “Materials and process engineering”, page 29). Typical application: y Pressure: < 40 MPa y Speed: < 1 m/s y Temperature: ‒30 °C to +100 °C y Medium: Hydraulic oils HL, HLP Double wiper DMRW2 U-ring T20 Guide ring Guivex SBK Omegat Cover Seal OMS-MR PR Guide Ring Guivex KBK Omegat OMK-MR Cover Seal Fig. 217 A typical rod/piston sealing system for higher requirements 462

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3. Seals and Sealing Systems Wiper Secondary seal Primary seal Housing Interspace Environment Pressure side/ operating chamber Piston rod Fig. 218 Elements and effective areas of a rod sealing system Guide In sealing consulting, one question is in- creasingly being asked: Why are so many individual elements and so much space required for sealing? Here is the answer: An “all-in-one” element, i.e. a combination of primary and secondary seal as well as wiper, may appear to make sense as a re- placement for a multi-part, space-inten- sive sealing system in individual applica- tions. However, its design is relatively complex. In addition, there is a risk that the individual functional areas of the seal will interfere with each other. As a rule, a multifunctional element of this type does not achieve the optimum in terms of sealing function, functional reliability, service life and design effort and costs. 3.3 THE PRESSURE RELIEF FUNCTION FOR SPECIAL OPERATING CONDITIONS PRESSURE DEFORMATION VOLUME AND INTERSPACE PRESSURE Due to the different drag oil transport of the primary and secondary seal, the space between the primary and secondary seal can be completely filled with hydraulic medium after only a few cycles during operation within a sealing system. The further introduction of medium leads to an increase in pressure in the interspace. If a U-ring is used as a secondary seal, its reversible deformation behavior under pressure acts as a volume compensator and thus helps to reduce the general pressure level (→ Fig. 219). Depending on the operating parameters, an interspace pressure of ideally up to 5 MPa is achieved in this way. With the return stroke, this pressure is reduced again with a time lag to the main chamber pressure. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 463 X E D N I

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Seals for Fluid Power Applications – Hydraulics Pressure buildup in the interspace With each stroke, a small amount of oil is transported into the space between the primary and secondary seal. Long strokes, higher stroke speeds and vibrations inten- sify this effect. Operation with a rapidly extending and slowly retracting rod is also unfavorable. If such operating parameters are present, a significantly higher pressure level is established in the interspace – initially temporarily. The higher pressure is only incompletely reduced during the return stroke and can be accumulated over a number of cycles. The pressure level can rise permanently to above the operating pressure. The increased pressure in the interspace results in an increase in frictional power. The temperature level rises and promotes deformation of the PTFE or TPU profile ring of the primary seal under load, which increases the risk of extrusion, i.e. migra- tion of the material into the extrusion gap on the non-pressure side. This also applies to the secondary seal. As a result of the higher friction, increased wear and, due to the frictional heat, accel- erated aging of the seal material must also be expected. If the pressure in the interspace is perma- nently increased as a result of the faults described above, the service life can be significantly shortened and/or the seal- ing system destroyed. Pressure relief As an extension of the functionality of the Omegat series, i.e. to prevent possible overpressure in the interspace as described above, the Omegat OMS-MR PR has a pres- sure relief bore (PR) integrated in the pro- file ring. The Syprim series has correspond- ing pressure relief channels. As soon as the interspace pressure p Z is greater than the main chamber pressure pH, the pressure relief bore or pressure relief channel is re- leased and reliably relieves the interspace down to the main chamber pressure (→ Fig. 220). Permanent confinement of ex- cess pressure in the interspace is not pos- sible here. Benefits of the pressure relief function Pressure relief maintains the pressure in the interspace at a level favorable for continuous operation, regardless of the operating conditions. As a result of the low thermal and mechanical stress on the sealing elements, stable long-term be- havior is achieved, which extends the ser- vice life of the sealing system. Due to the pressure relief functionality, the sealing system is tolerant of external influences acting during operation. Operational reliability is increased by the use of a pressure-relieved primary seal, such as the Omegat OMS-MR PR or a Syprim. Fig. 219 Deformation volume of a T20 U-ring under pres- surization 464

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3. Seals and Sealing Systems pZ < pH pZ > pH Pressure relief bore Interspace Main chamber Interspace Main chamber Fig. 220 Operating principle of the pressure relief function using the Omegat OMS-MR PR rod seal as an example 3.4 WIPERS – THE PROTEC- TIVE ELEMENT IN THE SEALING SYSTEM Depending on the requirements, wipers are designed as single or double wipers with an additional sealing edge and in different materials. sealing edge increases the operational reliability of the sealing system. Further information on the properties and applications of the various Freudenberg wipers can be found in the Product over- view on page 444 and in the product data sheets available there. The outward-facing wiper edge keeps ambient dirt safely outside the hydraulic system. A suitable design of the wiper edge ensures that the necessary lubricat- ing film can be fully drawn in during the return stroke. If required, an additional I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 465 X E D N I

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Seals for Fluid Power Applications – Hydraulics 3.5 GUIDE ELEMENTS IN THE HYDRAULIC CYLINDER The use of guide elements enables low- friction and low-wear relative movement between the components of the hydrau- lic cylinder (→ Fig. 221). The transverse loads occurring during operation are ab- sorbed in a defined manner with the aim of avoiding metallic contacts between the piston rod or the piston body and the housing parts. Performance of guide elements – record- ing and evaluating the influences The guide system is determined by the type of guide element, the material and the guide width as well as the guide ar- rangement. A number of influences must be checked and evaluated in order to di- mension the guide system for reliable functioning (→ Fig. 222). Depending on the application, individual influences may be of secondary relevance. Since there are interdependencies be- tween the individual influences, an isolat- ed consideration of individual aspects is usually not possible. Guides Rod seals Wiper Guides Piston seal Static seals Fig. 221 Elements of a sealing system 466 GEOMETRICAL INFLUENCING FACTORS ON THE HYDRAULIC CYLINDER – IDEAL VS. REAL In the idealized view of a cylinder, the center lines of the piston rod and the cylinder barrel are congruent. However, as a result of the guide play and the elas- tic deformation under load, an angular deflection α occurs between the piston rod or the piston body and the respective counter surface (→ Fig. 223). Depending on the angular deflection α and the deflection γ, the usable guide width is reduced compared to the geo- metrically summed width of the guide elements, especially in a double arrange- ment (→ Fig. 224). The calculation of the shear forces as well as the collision consideration on the basis of the idealized, axis-parallel view of the contacts lead to a supposedly higher pos- sible load absorption. Overloading of the guide elements as well as metallic contact can be the result. SELECTION OF THE GUIDE MATERIAL Depending on the objectives in the indi- vidual fields of application, guide elements made of fabric composites (laminated fabric), PTFE compounds and filled plastics or metallic guide elements are used for hydraulic cylinders (→ Tab. 23). Metal as guide material As a result of the angular deflection that occurs, rectangular metal guides experi- ence pronounced stress peaks in the edge area (→ Fig. 225). In the pressure zone, there is a lack of lu- brication. At low sliding speeds, stick-slip phenomena are to be expected here with

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3. Seals and Sealing Systems External force application and support spacing Deflection of the piston rod Angular deviation Extrusion gap Guide play Operating temperature Elastic deformation of the guide I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Fig. 224 Influences on the performance of the guide system (figure shows the profile of a Merkel® Guivex SBK guide element made of HG650 material) S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P a simultaneous high load on the counter surface (running-in). If the lateral load is applied abruptly in the limit zone, edge fracture in the guide area is also proba- ble. Laminated fabric as guide material The excessive stress in the area of the load-bearing edge is reduced by the use of rectangular guide elements made of fabric composites (laminated fabric). The elastic deflection of the laminated fabric guide increases the load-bearing length of the guide element and thus the maximum lateral load to be absorbed compared with the metallic guide. C I L U A R D Y H S R O T A L U M U C C A Fig. 222 Angular deflection between cylinder tube and piston rod S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 223 Reduction of the usable guide length due to angular deflection 467 X E D N I

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Seals for Fluid Power Applications – Hydraulics The result is a slightly outwardly curved (convex) shape of the cross-section of the guide on one side, which points to the bottom of the groove in both the rod and the piston variants (→ Fig. 226). The zone with the highest pressure is thus located in the center of the guide ring, even tak- ing angular deflection into account. The pressure decreases here on both sides (→ Fig. 225, right) and thus also facilitates the intake of lubricant. At the same time, the elastic deflection of the laminated fabric guide makes optimum use of the available width of the guide element. The collision check between the housing and the counter surface is more important due to the elastic deflection (→ Fig. 227) of the guide element. Compared to metal- lic guides, the use of guide elements made of laminated fabric is more cost-effective. Plastic/PTFE as guide material Guide elements are also made of plastics (PTFE compounds, PA with fibers, POM and others) and are used primarily in mobile hy- draulics. The value for the permissible sur- face pressure is significantly lower for plas- tic guide elements than for laminated fabric types, although it is also clearly tempera- ture-dependent. The advantage of such guide elements becomes clear when com- paring the costs for larger quantities. LAMINATED FABRIC TYPE WITH SPECIAL GEOMETRY – GUIVEX GUIDE ELEMENTS The development of the patented Guivex geometry for laminated fabric guide ele- ments started with the aim of reducing the excess stress in the edge area. MATERIAL LAMINATED FABRIC PTFE PLASTIC METAL + high transverse load + favorable price + medium load capacity + low guide play + feeding lubricant medium + mountability ∆ low transverse load + easy installation + low temperature dependence ∆ high temperature dependence ∆ high temperature dependence ∆ unfavorable load distribution ∆ metallic contact ∆ metallic contact ∆ metallic contact possible possible possible ∆ higher design effort ∆ expensive Tab. 23 Guide elements in comparison 468

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3. Seals and Sealing Systems Material: metal Geometry: rectangle Material: Geometry: rectangle laminated fabric Material: Geometry: GUIVEX laminated fabric High stress peaks in the edge area Stress peaks in the edge area No stress peaks in the edge area Fig. 225 Comparison of guide elements and their load distribution PROFILE THICKNESS OF THE GUIDE ELEMENT 1.5 mm vs. 2.5 mm vs. 4 mm Due to the load occurring during operation, the guide element deforms elastically (deflection → Fig. 227). This results in a radial movement. The greater the profile or tape thickness, the greater the elastic deformation for the same lateral load. The permissible deflection of the guide element is limited by the metal contact to be avoided at the narrowest extrusion gap. The strengths of the respective guide ele- ments are less pronounced in the other types: Guide thickness 1.5 mm + good mountability with small diameters Guide thickness 2.5 mm + well proven in practice for the combina- tion of narrow sealing gap with sufficient elastic deformation capacity Guide thickness 4 mm + high elastic deformation capacity + long contact length, i.e. high load-bear- ing capacity, even with larger angular deflections The mountability of the guide element is essentially determined by the nominal dia meter and the guide thickness. Not every combination of tape thickness and diameter is available. The respective product data sheet contains more detailed information. ELASTIC DEFORMATION OF METALLIC COMPONENTS Even in large, robustly designed industrial presses, very high operating forces can lead to bending moments and thus to elastic deformation of metal components. If these movements are transmitted transversely to a standard guide element of a hydraulic cylinder, the latter is not able to absorb the enormous forces in- volved. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Map-marker-edit Importance of elastic deformation S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 469 X E D N I

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Seals for Fluid Power Applications – Hydraulics Standard design (rectangle) Guivex design (radius/convex) edge pressure unrolling edge pressure no parallel contact sloping contact Fig. 226 The patented Guivex geometry compared with a standard rectangular guide element Guide elements with limited elasticity would be immediately destroyed by over- load. A thicker guide profile can be helpful in such cases. Thick guide profiles have a high deflection capacity, can usually completely avoid the deformation of the component and at the same time fulfill the actual guiding task within the scope of their remaining elasticity. Both the flexibility of the guide element and the deformation itself are limited by the maximum possible gap design in con- junction with the sealing elements used. A tolerated deflection of the component must not lead to a metallic contact of the sliding partners during the relative movement. Fig. 227 Elastic deformation of the guide element under load DIMENSIONING GUIDE ELEMENTS USING DIFFERENT APPROACHES FOR DIFFERENT OBJECTIVES – CATALOG VS. CALCULATION There are different approaches for dimen- sioning the guiding system and calculating the required guide width. On the one hand, the objective with regard to reliability and service life is decisive. On the other hand, the calculation options depend de- cisively on the scope and quality of the 470

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3. Seals and Sealing Systems information available for the respective application. Dimensioning level 1: The customer wants a replacement for an existing (competitor) product or a guide element for a given installation space: y operating conditions and the trans- verse load are not named or are not known y previously used element functions to the customer’s satisfaction, problems are not named or are not known y selection of a comparable guide ele- ment y selection of a guide element suitable for the installation space without cal- culation Dimensioning level 2: The customer specifies the required lateral load: y (basic) calculation of the required guide width depending on the available in- formation (→ Fig. 228). y definition of additional boundary con- ditions (e.g. gap dimension), if required A realistic estimate of the lateral load should take particular account of the limits of the mechanical load-bearing capacity of the metallic components. In the case of long, slim cylinders, for example, the permissible lateral load is limited by the bending strength of the piston rod, among other factors. The classical approach, in which about 10% of the hydraulic force is assumed as the transverse load, would in reality lead to buckling of the piston rod in many cases. If the magnitude of the applied normal force is defined, the minimum required guide width (H) can be determined in the simplest case via the projected area. F F H F = P x A; A = d x H; H = F / (d x P) H = Guide width [mm] F = Transverse load [N] A = Projected area [mm2] P = Permissible surface pressure [N/mm2] d = Nominal diameter of rod resp. piston [mm] Fig. 228 Calculation of the required guide width Some manufacturers of guide elements use a theoretical value for the specific surface pressure in their dimensioning or calculation and later correct it with the aid of an additional safety factor. In con- trast, Freudenberg Sealing Technologies uses empirically determined values for specific surface pressure without a cor- rection factor in its guide dimensioning. Consequently, if guide elements are to be compared with each other on the basis of the permissible specific surface pressure, any safety factors must be taken into account, otherwise a direct comparison Map-marker-edit Dimensioning or calculation of the guide Map-Marker-Exclamation When comparing permissible surface pressures pay at- tention to possible correction factors! I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 471 X E D N I

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Seals for Fluid Power Applications – Hydraulics will give a false impression of the perfor- mance of these guide elements. This is a quick and simple basic dimen- sioning without taking into account ge- ometric boundary conditions or operating conditions. The calculation is based on the mean value of the contact stress. The com- pressive strength as a material parameter is not explicitly taken into account. Dimensioning level 3: The customer specifies the application and the boundary conditions, including the transverse load and expects a com- prehensive consultation or calculation: y representation of the interrelationships between • temperature (→ Fig. 229) • deflection • gap • angular deflection and • permissible transverse load y calculation of the required guide width taking into account the known influ- ences (→ Fig. 228) Specific material parameters are re- quired for these calculations. The calcu- lation also requires in-depth knowledge of the relationships between the influ- encing variables. If an application needs to be considered in this depth, the appli- cation engineers at Freudenberg Sealing Technologies will be happy to help. 3.6 ADJUSTMENT: WAYS TO ADJUST THE GUIDE SYSTEM If the required lateral load is not achieved or if one of the set boundary conditions cannot be fulfilled, then an adjustment of the sealing system or, if applicable, a check and adjustment of the boundary conditions is necessary. Individual measures lead to changed val- ues at several points of the calculation. Sometimes changes appear beneficial, but are counterproductive in the overall context and in relation to the specific ob- jective. Especially with a large angular deflection, it is not recommended to determine the required guide width based on the parallel load. The FST application engineers will be happy to provide advice (→ chapter “Services,” page 7). If several guide elements are arranged one behind the other, individual guides are no longer engaged, depending on the angular deflection that occurs. The principle that ‘more helps more’ does not apply here (→ Fig. 231). Map-marker-edit Guide width for large angular deflections Map-marker-edit Specific material properties for calculation 472

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3. Seals and Sealing Systems I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A MEASURE IMPACT Detailing the conditions of use Specification of boundary conditions Detailing of the force application Specification of the necessary transverse load R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H Select alternative guide material Increase of the permissible transverse load Select a few wide instead of several narrow guide elements Increase of the contact length Increase of the permissible transverse load Increase the number of guide elements Increase of the permissible transverse load Increase space between guide elements Select tighter tolerances Select guide element with thickness 2.5 mm Reduction of angular deflection Increase of the permissible transverse load Reduction of angular deflection Increase of the permissible transverse load Reduction of angular deflection Increase of the permissible transverse load Increase of deflection/radial mobility Select guide element with thickness 4 mm Increase of contact length/permissible transverse load Increase tolerance width Increase of radial mobility Tab. 24 Measures for adapting a guide system and their effects R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 473 X E D N I

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Seals for Fluid Power Applications – Hydraulics FST: HGW HG650-p Competitor 2 Competitor 1 FST: HGW HG517 FST: PA 4112 Competitor 10 Competitor 9 FST: HGW HG600-p Competitor 3 Competitor 8 Competitor 4 Competitor 7 Competitor 5 FST: HGW HG650 Competitor 6 Reference 100%: maximum radial load, HGW HG650-p at +30 °C +30 °C +60 °C +80 °C +100 °C Fig. 229 Influence of temperature on the permissible lateral load for Freudenberg guides compared with the competition ] % [ d a o l l a r e a L t 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0 0.1 0.2 0.3 0.4 0.5 Angular deflection α [°] Deformation 0.15 mm Deformation 0.1 mm Deformation 0.05 mm Guide element 40 x 2.5 mm Guide element 9.7 x 2.5 mm 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 ] % [ d a o l l a r e a L t Fig. 230 Influence of angular deflection on the permissible lateral load for different guide widths 0 0.1 0.2 0.3 0.4 0.5 Angular deflection α [°] Deformation 0.15 mm Deformation 0.1 mm Deformation 0.05 mm 474

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3. Seals and Sealing Systems 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 Standard guide width 40 mm Standard guide width 9.7 mm 0.1 0.2 0.3 0.4 0.5 Angular deflection α [°] ] % [ d a o l l a r e a L t Deformation 0.15 mm Deformation 0.1 mm Deformation 0.05 mm Fig. 231 Maximum contact length as a function of deflection and angular deflection ] % [ d a o l l a r e t a L 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 0.05 0.1 0.15 0.25 0.25 Deformation [mm] Guide element 40 x 2.5 mm Guide element 40 x 4 mm Fig. 232 Influence of elastic deformation (deflection) on the permissible lateral load I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 475 X E D N I

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Seals for Fluid Power Applications – Hydraulics 4. FACTORS INFLUENCING THE SEALING SYSTEM THE EXTRUSION GAP The extrusion gap is defined as the gap on the side of the seal facing away from the pressure that is delimited by the counter surface and the housing. Due to the dif- ferent boundary conditions, the primary and secondary seal of a sealing system are considered separately with regard to the extrusion gap. Limit value consideration In a limit value analysis with regard to the extrusion gap, both the maximum extru- sion gap (xmax) and the minimum extrusion gap (xmin) are considered when the piston rod or piston body is positioned on one side (→ Fig. 233 and Fig. 234). Ødmin xmax xmin xf max ØD2max ØD2min Smin ØDFmax Fig. 233 Limit values of extrusion gap of rod sealing system Smin xf max xmax ØdFmin Ød2min Ød2max ØDmax xmax = (D2max – dmin) / 2 + xf max / 2 xmin = (D2min – [DFmax – (2*Smin)]) / 2 xf max = [DFmax – (2*Smin)] – dmin D2max = dmin + 2 xmax – xf max dmin = Minimum rod diameter [mm] DFmax = Maximum guide groove [mm] D2min = Minimum bore diameter behind seal [mm] seal [mm] [mm] D2max = Maximum bore diameter behind Smin = Minimum guide element thickness xmax = Maximum extrusion gap [mm] xmin = Minimum extrusion gap [mm] xf max = Maximum guide play [mm] xmax = (Dmax – d2min) / 2 + xf max / 2 xmin = ([dFmin + (2*Smin)] – d2max) / 2 xf max = Dmax – [dFmin + (2*Smin)] d2min = Dmax + xf max – 2 xmax Dmax = Maximum bore diameter [mm] dFmin = Minimum guide groove [mm] d2min = Minimum piston diameter behind seal [mm] d2max = Maximum piston diameter behind seal [mm] Smin = Minimum guide element thickness [mm] xmin xmax = Maximum extrusion gap [mm] xmin = Minimum extrusion gap [mm] xf max = Maximum guide play [mm] Fig. 234 Limit values of extrusion gap of piston sealing system 476

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4. Factors Influencing the Sealing System The maximum extrusion gap (xmax) should be as small as possible (→ gap extrusion), while the minimum extrusion gap (xmin) should be as large as possible (→ metallic contact). Since there is a direct geometric dependency between the minimum metallic gap (xmin) and the maximum per- missible extrusion gap (xmax), the gap dimen sions cannot be set independently of each other. Gap extrusion Sealing materials behave like a viscous liquid under the influence of operating pressure. As pressure is applied, the seal- ing element is increasingly pressed against the metallic housing and towards the extrusion gap. The extrusion of the sealing material into the extrusion gap is referred to as gap extrusion. With the ex- trusion of the sealing material into the ex- trusion gap, the sealing element is dam- aged in the area of the metallic housing edge. The repeated damage ultimately leads to the failure of the sealing ele- ment. When determining the maximum gap di- mension (xmax), both the temperature, material- and geometry-dependent di- mensional stability of the sealing ele- ment and the operating and boundary conditions must be included in the con- siderations. In addition to the obvious correlation be- tween the dimensional stability of a seal- ing element and the operating pressure or operating temperature, the limit val- ues for the sealing gap are determined, among other things, by the load spectrum. The pressurization with simultaneous rel- ative stroke movement in the direction of the extrusion gap is more demanding in terms of frictional power and shear forces in the contact zone than static or quasi- static sealing. A short pressure pulse is not critical with regard to gap ex- trusion, while a long pressure holding time places increased demands on the long-term dimensional stability of the sealing element (material flow). Particularly in the case of higher operating pressures or lightweight designs, the rel- evant increase in the extrusion gap due to tube expansion (cylinder tubes) or tube compression (hollow rods) must be taken into account. In the case of limit-value de- signs with high lateral loads, the deflec- tion of the guide elements may also have to be taken into account. General data for the maximum permissible gap dimension (xmax) are shown in corre- sponding tables in the article description depending on the seal type, the selected seal profile and the operating pressure. Metallic contact When determining the minimum gap dimension (xmin), collision control is of particular importance. Within a sealing system, the narrowest extrusion gap is normally found behind the primary seal of a sealing system or behind the main seal of a single sealing system without secondary seal. Collision checking is therefore primarily carried out for these areas. In the case of large distances between the sealing elements due to the design as well as large angular deflections, the collision check should be extended ac- cordingly, e.g. metallic contact may occur in the area of the wiper. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 477 X E D N I

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Seals for Fluid Power Applications – Hydraulics Gap dimensioning with high lateral loads and long, slim cylinders may have to be secured with regard to the deflection of the piston rod and the deflection of the guide elements. Cylinders with a short distance between the rod and piston guide elements are checked with regard to the angular deflection that occurs. Metallic contacts between the counter surface and the housing parts result in comparatively high follow-up costs in the event of servicing. Within the permissible limits and taking into account the oper- ating and boundary conditions, the di- mensions and tolerances are therefore selected in such a way that the largest possible value is set for the extrusion gap xmin and thus the greatest possible safety against metallic contacts. The minimum required value for xmin is essentially deter- mined by the deflection of the guide element under load (→ “Design of guide elements”, page 470). 478

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5. SEALING MATERIALS 5. Sealing Materials The function of a sealing element is sig- nificantly influenced by the sealing ma- terial. In addition to chemical stability, dimensional stability, abrasion behavior and elastic behavior are key influencing factors. In the simplest case, deficiencies are compensated for by using additional elements, such as back-up rings or preload- ing elements. y the operating conditions and their weighting influence the selection of materials y the properties of the selected materi- al determine the possible geometry y the properties of the selected seals and guides determine the arrange- ment in a sealing system and their function, respectively A function-oriented design of the seal is always also carried out with a view to the specific properties of the sealing material used. Not every geometry can be sensibly produced from every material. For more information, see also → chapter “Materials and process engineering”, page 29. For example, in the Omegat compact seal, an O-ring or elastomer profile ring presses on the PTFE sealing body to gen- erate the desired force of the PTFE seal- ing edge on the counter surface. The manufacture of multi-component seals, on the other hand, is somewhat more complex. Here, two materials with differ- ent properties are firmly bonded together. The following system should be observed for effective sealing selection (→ Fig. 235): OPERATING CONDITIONS COUNTER SURFACE SEALING MATERIAL SEALING GEOMETRY SEALING ARRANGEMENT FUNCTION SEALING EFFECT SERVICE LIFE INSTALLATION SEALING EFFECT SERVICE LIFE Fig. 235 Influencing factors and dependencies in the selection of a seal I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 479 X E D N I

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Seals for Fluid Power Applications – Hydraulics 5.1 COMMON SEALING MATERIALS IN HYDRAULICS y Polytetrafluoroethylene (PTFE) com- pound in conjunction with elastomer preloading elements or steel springs for seals and wipers y Polyethylene (UHMW-PE) in conjunction with elastomer preloading elements or steel springs for seals and wipers y Polyurethane (AU) for seals and wipers y Elastomers (NBR, FKM, HNBR) for seals and wipers y Fabric composites with plastic matrix (laminated fabric) for guide elements y Polyamide (PA) for guide elements and back-up rings y Fabric composites with elastomer for seals and wipers y Polyoxymethylene (POM) for back-up rings and guide elements The following overview (→ Tab. 25) com- prises a limited selection of Freudenberg materials. For special media or applica- tions, Freudenberg Sealing Technologies has access to a wide range of additional materials on request (→ chapter “Materials and process engineering – 3. General mate- rial selection and descriptions”, page 48). Pure (virgin) PTFE has low structural and abrasion resistance. Even at low loads, the material deforms and begins to flow (cold flow). By adding fillers (compounding) such as bronze, glass fibers and carbon fibers, both dimensional stability and abrasion resistance can be relevantly improved. PTFE and PE seals are manufactured by machining up to a diameter of approx. 2,400 mm. Production by injection mold- ing is not possible. Examples of typical Freudenberg designs are shown in → Fig. 236 (see also → chapter “Service – LC Freudenberg Xpress® Customized Solutions”, page 20). 480

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5. Sealing Materials 5.2 PTFE COMPOUNDS AND POLYETHYLENE SEALING MATERIALS DESCRIPTION FILLING MATERIAL PTFE B602/B604 Bronze PTFE GM201/GM202 Glass fiber + MoS2 PTFE C104 Carbon fiber PTFE B100 (Quantum) PE E083/E084 Brass – COLOR Brown Light gray Anthracite Dark green White Tab. 25 Overview of standard PTFE compounds and polyethylene sealing materials Merkel® Rotomatic series M15 Merkel® Omegat series OMS-D R HB Merkel® double wiper series PT1 Merkel® double wiper series PT2 Merkel® Omegat series OMS-M R PR Merkel® Omegat series OMS-S SR Merkel® double wiper series PT3 Merkel® Omegat series OMK-MR Merkel® V-Packing Set series ES61 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 236 Profiles of typical Freudenberg seals made of PTFE (→ Product overview from page 418) 481 X E D N I

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Seals for Fluid Power Applications – Hydraulics CHARACTERISTIC SEALING PROPERTIES OF PTFE COMPOUNDS + Δ y Very good extrusion resistance y Very good media resistance • Depending on the compounding • Water-based hydraulic media y Very low coefficient of friction y Wide temperature application range y Interaction with the counter surface depending on compound, medium and operating conditions y Sealing effect in the low-pressure range y Long-term behaviour under load (material flow) y Preload element required (two-part seal) y Can only be produced by machining y Sensitive to mechanical damage CHARACTERISTIC SEALING PROPERTIES OF POLYETHYLENE MATERIALS + Δ y Very good wear resistance to ceram- y Operating temperature up to max. ic counter surfaces y High resistance to extrusion y Good dry running properties y Low coefficient of friction y Universal media resistance y Robust • Uncomplicated handling • Insensitive to dirt +80 °C y Cost of materials y Sealing effect in the low-pressure range y Preload element required (two-part seal) y Can only be produced by machining PTFE sealing elements are preferably used as a primary seal within sealing sys- tems or as a piston seal for pressurization on both sides. Adhering contamination on the piston rod can be kept safely outside the hydraulic system with suitable design of the wiper edge with wipers made of PTFE com- pound and PE. Elastomers such as NBR are less suitable here. 482

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5. Sealing Materials SELECTION TABLE PROPERTIES/CRITERIA PTFE B602 PTFE B604 PTFE GM201 PTFE GM202 PTFE C104 PTFE B100 PE E083/84 High wear resistance High resistance to extrusion Low influence on the counter surface Good suitability on chrome- plated counter surfaces Good suitability on ceramic- coated counter surfaces Good suitability on carbide coated counter surfaces Good suitability for short stroke applications/applications with deficient lubrication Good suitability in aqueous hydraulic media + ++ ++ ++  +   ++ +++ ++ ++  + +  Temperature application range > +80 °C +++ +++ +++ very well met ++ well met + met  not met + + ++ +++  + ++ ++ ++ ++  + +++ +++ ++ + ++ ++ ++ +++ +++ +++ + ++ ++ +++ ++ +++ ++ +  ++ ++ ++ +++ ++ +++ +++ +++ ++ + +++ +++ +++  Tab. 26 Relative evaluation of PTFE compounds for general applications in sealing technology I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B The selection table (→ Tab. 26) refers to general applications in the medium load range. In specific applications, the rela- tive evaluation of individual properties may shift. Map-marker-edit General selection table S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 483 X E D N I

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Seals for Fluid Power Applications – Hydraulics 5.3 POLYURETHANE SEALING MATERIALS DESCRIPTION 92 AU 21100 93 AU V167 94 AU 20889 94 AU 21730 94 AU 30000 94 AU 925 94 AU V169 95 AU V142 95 AU V149 98 AU 30500 98 AU 928 98 AU V211 COLOR OUTSTANDING FEATURE Light beige Low temperature suitable Red Blue Blue Blue Blue Blue Dark blue Dark blue Blue Blue Hydrolysis resistant Best chemical resistance Food grade Wide temperature application range and hydrolysis resistant Standard Low temperature suitable Standard Standard Wide temperature application range and chemical resistance (e.g. hydrolysis) High extrusion strength Light yellow Extrusion resistant Tab. 27 Overview of standard polyurethane sealing materials Polyurethane sealing elements can be manufactured by injection molding or machining up to a nominal diameter of 2,400 mm. Individual polyurethane grades are characterized by special properties. For more information, please refer to the relevant product data sheet. Other ma- terials are available on request. Seals made of polyurethane are used both as secondary seals and as primary seals within sealing systems. They are also commonly used as a single seal in PU material 94 AU 30000 PU material 98 AU 35000 484 conjunction with a double wiper. Due to its high wear resistance, polyurethane is also an excellent material for wipers. The resistance of polyurethane in hydraulic oils has also helped to establish this material as a standard in a large number of hydraulic applications.

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5. Sealing Materials Cover Seal series PU83 U-ring series T20 Piston seal series Simko 300 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Wiper series PU5 U-ring series LF300 S L A E S C I T A T S Piston seal series T18 Double wiper series PRW1 Piston seal series OMK-PU Fig. 237 Profiles of typical Freudenberg brand seals made of polyurethane (→ Product overview from page 418) CHARACTERISTIC SEALING PROPERTIES OF POLYURETHANE + Δ G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B y Good sealing effect y High resistance to extrusion y Good friction behavior y High resistance to wear y One-piece seals y Robust • Uncomplicated handling • Easy installation • Insensitive to dirt y Temperature in contact with water up to max. +40 °C/+60 °C y Media resistance S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 485 X E D N I

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Seals for Fluid Power Applications – Hydraulics 5.4 ELASTOMERS In hydraulic applications, NBR (acrylonitrile- butadiene rubber) or FKM (fluorocarbon rubber) are also used as sealing materials. Depending on the boundary conditions, HNBR (hydrogenated acrylonitrile-buta- diene rubber) and EPD M (ethylene-pro- pylene-diene rubber) are also used. Elastomer seals with fabric reinforce- ment, e.g. V-Packing Sets, are robust and sufficiently dimensionally stable when pressurized. Due in particular to their unfavorable frictional behavior, such sealing elements often do not meet the increasing requirements in terms of stroke speed and service life. Elastomers are used as seals, wipers and in the form of O-rings as static seals or preload elements. Elastomere seals are used e.g. when polyurethane cannot be selected in terms of media resistance or operating temperature. Preload element of Omegat OMS-S SR Double wiper series P8 O-ring Compact seal series L43 Merkel® V-Packing Set ES U-ring series NA250 Fig. 238 Profiles of typical Freudenberg brand seals made of elastomer material (→ Product overview from page 418) 486

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5. Sealing Materials CHARACTERISTIC SEALING PROPERTIES OF ELASTOMER MATERIALS + Δ y Very good sealing and wiping effect y Very good elastic behavior • Responsiveness • Compression set • Restoring force y Good media resistance • Material specific (NBR, FKM ...) • Water-based hydraulic media y Wide temperature application range material specific (NBR, FKM ...) y One-piece seals y Resistance to extrusion Can only be used at low pressure up to 10 MPa without additional back- up ring y Coefficient of friction y Resistance to wear y Adhesion during prolonged standstill I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 487 X E D N I

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Seals for Fluid Power Applications – Hydraulics 5.5 LAMINATED FABRICS DESCRIPTION HGW HG517 HGW HG600 HGW HG650 COLOR Gray-black Gray Red DELIVERY FORM Bushings d ≤ 300 mm Metre goods d > 300 mm Bushings d ≤ 300 mm Metre goods d > 300 mm Tab. 28 Overview of laminated fabric materials for Freudenberg brand guide elements influence of the operating temperature on the permissible surface pressure is only slight. The performance of Freudenberg laminated fabrics compared with competitive products is shown in → “3.5 Guide elements in the hydraulic cylinder,” page 466. In order to avoid metallic contact, the geometric boundary conditions as well as the material properties must be taken into account when dimensioning the guide system. For further details, see → “3.5 Guide elements in the hydraulic cylinder,” page 466. Fabric composites (laminated fabrics) are often used for guide elements. Laminated fabric consists of a fine fabric bonded with synthetic resin. The proper- ties of the components determine the relevant parameters such as abrasion resistance, permissible surface load (ab- sorption of lateral load) and temperature dependence. Polyester and other plastics, but also nat- ural materials such as cotton, are used for fine fabrics. In addition to polyester, vinyl ester and phenolic resins, a whole range of plastics with different properties are available for the resin matrix. While the abrasion resistance of the com- pounds established on the market is at a comparably high level, there are relevant differences both in the permissible load per area unit and the dependencies on the operating temperature. Thermo- plastic base materials, such as polyester, naturally show a clearly temperature- dependent material behavior. At higher temperatures, guide elements made of these materials can only absorb low lateral loads. For other compounds, the 488

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5. Sealing Materials DELIVERY FORM Bushings d ≤ 200 mm I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H Bushings d ≤ 200 mm 5.6 POLYAMIDE (FILLED) DESCRIPTION PA 4112 QUANTIX 52-4 COLOR Black Black Tab. 29 Overview of filled polyamide materials for Freudenberg brand guide elements Filled polyamide is used for guide elements and unfilled polyamide is frequently used for back-up rings. The use of fillers specif- ically improves the mechanical properties of the base material. Polyamide guide elements can be manu- factured by injection molding. For larger quantities, guide elements made of filled polyamide are an inexpensive alternative to guide elements made of laminated fabric. The use limitations must be taken into account. R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 489 X E D N I

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Seals for Fluid Power Applications – Hydraulics 6. INFLUENCING FACTORS 6.1 FRICTION IN THE TRIBOLOGICAL SYSTEM Tribology is the science of friction, wear and lubrication of bodies moving against each other. High friction influences the function and long-term behavior of a sealing element in the fluid cylinder. The resulting heat usually leads to excessive wear. The friction of seals cannot be given as a simple value. It depends on a large number of influencing variables including complex physical interactions. Possible influencing factors: y friction partners (material properties of seal and counter surface) y surface structure of counter surface y surface pressure in the contact zone y relative velocity between the friction partners y lubricant (type, aging condition, visco- sity) y contamination (abrasion, external in- fluences) Precise knowledge of the application and all influencing factors is a basic pre- requisite for low friction and, above all, for the appropriate selection and successful use of a sealing system. Map-marker-edit Knowledge of application and influencing factors Stribeck curve 1 Static friction 2 Mixed friction 3 Fluid friction τ = η du –– dy - Viscosity - Lubricant stiffness - Time - Temperature e c r o f l a n o i t c i r F Stick-slip Transitionalpoint t (s) - Viscosity - Pressure - Temperature Static friction Mixed friction Liquid friction Speed Fig. 239 Stribeck curve using the example of an elastomer material in contact with a metallic counter surface 490

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6. Influencing Factors this area of fluid friction (→ area 3 in Fig. 239), the sliding partners are support- ed by a fluid film. Resistance to this relative movement is essentially provid- ed by the viscosity of the fluid film (see also → chapter “Materials and process engineering – 3. General material selec- tion and descriptions”, page 48). STICK-SLIP IN THE AREA OF MIXED FRICTION An undesirable characteristic of a seal, e.g. in a positioning cylinder, is the so-called stick-slip behavior. It describes the con- tinuous alternation between sliding and sticking of the friction partners. Stick-slip is primarily influenced by the material properties and the system stiffness. For example, a long-stroke cylinder with long and soft pressure hoses at low op- erating pressure and a fluid with high compressibility (e.g. compressed air or oil with a high proportion of dissolved air) has low system stiffness. Stick-slip can cause audible vibrations of the assembly during cyclic recovery and can be observed in both cases, dry or lu- bricated contact. If a sealing system exhibits stick-slip be- havior, the choice of a different seal type is of little help. Design measures to increase system stiffness are the primary recom- mendation. Freudenberg Sealing Technologies there- fore recommends detailed discussions with the seal manufacturer. BASIC MECHANISM OF FRICTION Moving machine elements undergo dif- ferent contact states depending on their motion relative to each other. This contact behavior produces different types of fric- tion and is usually described by the Stribeck curve (→ Fig. 239). If there is no relative movement, the peaks of the contact partners surfaces get in touch first. The sum of these contact points can vary over time. Both operating media and elastomeric sealing materials have strongly time-de- pendent material properties. Softer, flow- able or creepable materials, for example, yield to the local load over time, which in- creases the contact zone. Higher friction is the result. At the first attempt to move the friction partners relative to each other, the resist- ance due to static friction is initially very high. This effect is mainly caused by ad- hesion processes and interlocking of the surfaces (→ area 1 in Fig. 239). If the drive energy increases, an initial rel- ative movement takes place. Areas with contact lose this until they encounter re- sistance again. This is the area of mixed friction (→ area 2 in Fig. 239). This behav- ior is strongly influenced by the surface roughness and the material properties of the sliding partners. At higher drive energy and relative speed, the friction partners lose contact with each other due to the hydrodynamic effect. In Map-marker-edit Remedy for stick- slip behavior I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 491 X E D N I

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Seals for Fluid Power Applications – Hydraulics FRICTION BEHAVIOR OF ELASTOMER MATERIALS A special property of elastomers is their entropy elasticity. The stiffness and elon- gation of elastomers depend on temper- ature and frequency. Thus, friction does not follow Coulomb’s law. It is not exclu- sively dependent on the normal force, as is the case with metals, for example (→ Fig. 240). In a seal operating in normal service with low wear behavior, the deformation and adhesion components are the main in- fluences on the friction behavior. The deformation component depends on the speed at which the load in the contact zone changes and the operating temperature. The adhesion portion of the friction is strongly influenced by the surface prop- erties of the sliding partners. The breakaway force of elastomer seals is almost three times higher than the force required to overcome their sliding friction. At high operating pressures and low stroke speeds, pronounced stick-slip behavior can be observed. FRICTION BEHAVIOR OF THERMOPLASTICS Compared to elastomer seals, seals made of thermoplastics, such as PTFE or UHMWPE (ultra-high molecular weight polyethyl- ene), require a low breakaway force and exhibit almost stick-slip-free behavior. The sliding friction is also significantly lower with thermoplastics. Another ad- vantage of PTFE is its better temperature resistance, which allows greater sliding speeds, especially at higher operating pressures. The friction of elastomers is described as the sum of several friction components: y deformation (also hysteresis) component from the deformation of the elastomer y adhesion component from the interac- tion in the contact area with the counter surface y cohesion component based on the en- ergy required for crack generation and crack growth y fluid friction component due to the flow of the medium between the friction partners Elastomer Deformation friction (hysteresis friction) Energy dissipation due to damping of the elastomer Fluid friction, viscous friction Fluid Adhesive friction Interaction of surfaces Solid body Velocity FR = FR Def + FR Adh + FR Koh + FR Fi Fig. 240 Friction of elastomers 492

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6. Influencing Factors 6.2 COUNTER SURFACE – PART OF THE TRIBO- LOGICAL SYSTEM The quality – topography and material – of the counter surface has a significant influence on the functionality, leakage behavior and wear of a seal in the tribo- logical system. The tribological system in sealing technology consists of a base body (seal), a counter body (counter sur- face), an intermediate material (operating medium) and an ambient fluid (air, spray water, seawater, dust, dirt, etc.). In an optimally adjusted sealing system, a thin film of oil is released to the outside under the sealing elements when the piston rod of a hydraulic cylinder is ex- tended. During the return stroke, this film is completely transported back into the hydraulic system to prevent leakage. This oil film, also known as drag oil, can be very thin, but due to the surface struc- tures, it will never completely break off even at the highest pressure of the sealing edge on the counter surface. In a sealing system with several elements, a certain oil film is even desired to reduce friction and wear. In order not to disrupt ideal functionali- ty between the sealing edge and the counter surface in the tribological sys- tem or to avoid possible leakage, scor- ing, scratches, shrinkage cavities or con- centric or spiral machining grooves as well as damage to the counter surface should always be avoided. SURFACE FINISHING In addition to the sealing elements and guides of a sealing system, the compara- tively hard counter surface is also stressed by media, friction and pressure (lateral load and operating pressure). To protect against corrosion, wear and deformation, piston rods of hydraulic cyl- inders must be surface treated. For many years, galvanic processes (hard chrome plating, application of chromium-nickel layers) and thermo-chemical processes (nitrocarburizing with and without oxi- dizing aftertreatment) have been used industrially for this purpose. Wear-resistant and dimensionally stable surface coatings of the material are pro- duced by hardening and/or hard chromi- um plating of the running surfaces. The alloy and thickness of the coatings de- pend on the use of the piston rod. Long thin rods with a lot of bending have more flexible coatings than, for example, pis- ton rods in large-dimension cylinders for presses. In addition to the coating prop- erties that are important for the particu- lar application, such as hardness, porosi- ty or adhesion, there are other important characteristics for assessing the coating that can be measured or determined with little effort. These include, for example, roughness measurement, which is de- scribed later in this section. However, chrome-plated or chrome-nickel coated piston rods offer only moderate corrosion protection for the base material due to microcracking of the applied coat- ing. In addition, there is a risk of scoring on the surface due to foreign bodies entering the sealing and guide elements during operation, which leads to a wear-related Map-marker-edit Avoid scoring, scratches and voids I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 493 X E D N I

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Seals for Fluid Power Applications – Hydraulics change in the surface quality with in- creasing operating time. In addition, the ban on the use of Chrome VI, which has been in force since September 2017, is contributing to a sharp decline in chromed surfaces. If not finished, nitrided counter surfaces have deep pores. Even at low loads, abra- sive particles break out of the porous bonding layer. With appropriate finishing, nitrided counter surfaces are nevertheless well suited for contact with sealing ele- ments. In order to meet market requirements for, among other things, higher wear resist- ance and corrosion resistance, thermal spraying became established as a surface finishing process. Compared with chro- mium coatings with a thickness of 20 µm, thermally sprayed coatings are at least 100 µm thick. Different alloys are used depending on the requirements. The structure of the sprayed layer is sig- nificantly influenced by the spraying pro- cess itself, the set process parameters, the spray additive and the finishing. For self-flowing alloys, the post-treatment is decisive. Compared to a conventional chromium layer, the HP-HVOF (high velocity flame spraying) and plasma sprayed layers have a process-related residual porosity and correspondingly different surface struc- tures. Coatings applied by alternative methods such as laser cladding or fusion bonded coatings (self-flowing alloys) are virtually void-free, but offer lower surface hard- ness. In high velocity flame spraying, the top lay- er is usually a chromium carbide/tungsten carbide coating in a metal matrix which serves as a binder for the carbide. This is also referred to as a hard metal coating. The coatings have very good adhesion and show excellent corrosion resistance. Due to the high density of such coatings (closed porosity < 1%), roughness values of R a 0.05 μm can be achieved. The average thickness of the coating is 150 μm, and its hardness is between 950 and 1,650 HV. Atmospheric plasma spraying uses oxide ceramics, e.g. Al2O3. In very harsh environ- ments, a nickel/chromium-based interme- diate coating is applied to ensure corrosive resistance. Due to the high porosity < 3%, roughness values of R a 0.15 μm can be achieved. The average thickness of the coating is 200 μm, and its hardness is be- tween 850 and 1,100 HV. However, plasma coatings have a perma- nently sharp-edged crystal structure and are not smoothed in contact with the sealing elements either during the run- ning-in phase or in later continuous op- eration, which can lead to high wear on the sealing elements. For this reason, sealing systems for ceramic counter sur- faces consist of special materials and an adapted arrangement of the seals. While ceramic counter surfaces have been relevant to the market for many years and are used despite their disadvantage of a limited choice of sealing materials/ geometries, thermally sprayed carbide layers are becoming increasingly impor- tant. The HP-HVOF process (High Pres- sure High Velocity Flame Spraying) is leading the way. HP-HVOF stands for High Pressure – High Velocity Oxygen Fuel. 494

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6. Influencing Factors y unchanged roughness values mean that the tribological properties of the coating remain the same throughout the entire service life of the seal y when replacing a seal, an HP-HVOF coated counter surface can be consid- ered as new Knowledge of the interaction between the sealing material and the sprayed coating of the counter surface is becom- ing increasingly important and requires cooperation between the seal manufac- turer and the coater. It is ideal if the coat- er provides suitably machined piston rods for test runs to determine the surface characteristics and seal compatibility. The results of the tests carried out so far at FST together with a renowned partner in surface finishing allow a significant initial conclusion to be drawn: coatings with the preferred HP-HVOF process are universally suitable for all sealing mate- rials. In combination with polyurethane, HP-HVOF-coated surfaces show their true capabilities in the tribological system. Explanations are given at the end of this section. Map-marker-edit Suitable sealing material for HP-HVOF- procedures In this process, liquid or doughy coating particles impact the cleaned and rough- ened component at high velocity. The particles are deformed by the impact and spread over the roughened surface. The hot particles transfer their heat to the colder base material, shrink and adhere to the surface irregularities. This type of mechanical anchoring results in strong adhesion of the coating. Such thermally sprayed coatings have a certain residual po- rosity due to the manufacturing process. Compared to sprayed ceramic coatings (plasma spraying), HP-HVOF spraying produces very homogeneous and dense coatings. The sprayed layer has a lamellar structure. The torch moves repeatedly over the surface and sprays the surface layer by layer. A typical layer thickness is 10 to 15 μm. Compared to sprayed ceramic layers, hard metal layers (tungsten carbide, chromium carbide) exhibit the following properties: y very high surface hardness and dense layer structure y extreme wear resistance and durability y due to the high density (porosity < 1%), a very smooth surface can be achieved by final machining. The roughness is set between R a 0.05 and 0.2 μm, de- pending on the optimum roughness for the selected seals y no restrictions on seal selection and materials Compared to a chromium layer, other properties are relevant: y in contrast to the running-in behavior of a chromium coating, the roughness values of HP-HVOF-coated counter surfaces remain virtually unchanged even in long-term tests I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 495 X E D N I

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Seals for Fluid Power Applications – Hydraulics measured surface profile. The roughness profile (R-profile) is created by the filter- ing required for readability according to DIN EN ISO 16610-21 (→ Fig. 241). The selection of the cut-off wavelength λC according to DIN EN ISO 4288 is deci- sive for the filtering result. It is selected de- pending on the surface to be measured, either according to the groove spacing (for periodic profiles) or according to the roughness values to be expected for ape- riodic profiles. At the same time, the total measuring distance and the associated scanning distance are bindingly defined in accordance with the standard (→ Fig. 242). EVALUATION OF THE MEASUREMENT RESULTS According to DIN EN ISO 4288, the surface measurement should be carried out where the highest values are to be expected (visual determination). However, a single profile section does not characterize the entire surface with sufficient statistical certainty. For this reason, a meas- urement strategy that does justice to this fact has already been standardized for years. Aperiodic profiles e.g. grinding, eroding Fig. 241 Typical roughness profile of a surface measurement with the contact stylus method SURFACE ASSESSMENT In order to assess the suitability of coun- ter surfaces for contact with sealing and guiding elements, their surfaces are ex- amined with tactile or optical measuring instruments. Even though the optical in- struments work without contact and have a much better resolution, the contact stylus method is often used in practice. Corresponding devices detect the profile of a surface in two dimensions. A probe with a diamond tip moves perpendicular to the direction of the groove over the surface of the shaft and the perpendicu- lar stroke of the probe tip is converted into an electrical signal. The unfiltered primary profile (P-profile) is the actual Periodic profiles e.g. turning, milling Measuring conditions lr ln lt λc λs rtip Ra Single measuring section Measuring section Sensing distance Cut-off wavelength Short wavelength profile filter Probe tip radius Arithmetic mean roughness RSm [mm] > 0.013 … 0.04 > 0.04 … 0.13 > 0.13 … 0.40 > 0.40 … 1.30 > 1.30 … 4.00 λc = lr [mm] 0.08 0.25 0.80 2.50 8.00 ln [mm] 0.40 1.25 4.00 12.50 40.00 lt [mm] 0.48 1.50 4.80 15.00 48.00 rtip [mm] 2.00 2.00 2 or 5 5.00 10.00 λs [mm] 2.50 2.50 2.50 8.00 25.00 R a [µm] > (0.006) … 0.02 > 0.02 … 0.10 > 0.10 … 2.00 > 2.00 … 10.00 > 10.00 … 80.00 Rz [µm] > (0.025) … 0.10 > 0.10 … 0.50 > 0.50 … 10.00 > 10.00 … 50.00 > 50.00 … 200.00 Fig. 242 Determining the presettings for the contact stylus method 496

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6. Influencing Factors This strategy is generally known as the “16% rule.” A surface is assumed to be “good” if no more than 16% of the meas- ured values of a parameter exceed the specified maximum value (see also DIN EN ISO 4288:1997). The rule applies if no maximum values are specified for the pa- rameters to be measured. The 16% rule requires the following procedure when measuring with the profile-sectioning contact stylus method: y if the measured value exceeds 70% of the tolerance during the first measure- ment, two further measurements must be carried out at a different location. These must then be within the toler- ance or y with six measurements distributed over the surface, one measured value may be out of tolerance. ROUGHNESS PARAMETERS The most important roughness para- meters according to DIN EN ISO 4287 (→ Fig. 243): Ra: Rz: arithmetic mean roughness R a is the arithmetic mean rough- ness from the contributions of all profile values averaged roughness average of the five R z values from the individual measured sections lr Rz1max: maximum roughness depth largest R z value from the five in- dividual measurement sections lr Rmr: material share proportion of total line sections running in the material in rela- tion to the total line (in %) In accordance with these standard sur- face characteristics, FST recommends the following limit values for hardened and ground counter surfaces (→ Tab. 30). In the meantime, practice has shown that the typical parameters Ra, Rz and Rz1max are not sufficient to adequately describe the specific requirements of the hard-soft contacts in the tribological system. A further complicating factor is that these parameters vary in the range from ‒20% to +30%. For this reason, the so-called “RK param- eters” are used for the metrological de- scription of counter surfaces (→ Fig. 244), which are derived from the Abbott-Fire- stone curve (DIN EN ISO 13565-1). Rpk: Rk: Rvk: Mr1, Mr2: Material share Reduced peak height Core groove depth Reduced groove depth lt Rz1 Rz2 Rz3 Rz1max Rz4 Rz5 lr ln = 5x lr Pre-run section Trail Fig. 243 Determination of the surface value Rz I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 497 X E D N I

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Seals for Fluid Power Applications – Hydraulics FST RECOMMENDATIONS FOR STANDARD SURFACE CHARACTERISTICS HARDENED AND GROUND SURFACES RZ1max Ra MATERIAL SHARE Rmr Sliding surface ≤ 2.5 μm 0.05 … 0.3 μm Groove Groove sides ≤ 6.3 μm ≤ 15 μm ≤ 1.6 μm ≤ 3 μm Tab. 30 Standard surface characteristics recommended by FST Rmr > 50% to max. 90% with cutting depth c = Rz/2 and reference line Cref = 0% (optimum Rmr = 80%) Note: The Abbott-Firestone curve derived from the surface measurement must have an S-shaped course and may only have one inflection point. This is impor- tant to avoid misinterpretations. See also → Fig. 246. These extended characteristic values are essential for an exact assessment of the counter surface with regard to abrasive- ness, long-term behavior and lubricant deposits (→ Fig. 245). Rpk Rk Rvk Balancing line Mr1 Mr2 Total measured distance Lt 0 20 40 60 80 100 Material content [%] Fig. 244 Extended surface characteristics based on the Abbott-Firestone curve Wear Long-term behavior Lubricant deposit Fig. 245 Interpretation of a surface topography for suitability as a counter surface of a seal 498

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6. Influencing Factors HP-HVOF * PLASMA ** HARD CHROME THERMO CHEM. PROCESS*** 0.05 ... 0.15 µm 0.15 ... 0.40 µm 0.10 ... 0.25 µm 0.05 ... 0.30 µm < 0.10 µm < 0.10 µm < 0.30 µm < 0.50 µm 0.10 ... 0.60 µm 0.20 ... 1.5 µm 0.20 ... 0.50 µm 0.20 ... 0.65 µm – – – – – – – – – – – – ≤ 2.50 µm 0.25 ... 0.7 µm ≤ 0.50 µm 0.20 ... 2.0 µm Ra Rpk Rvk Rz1max Rk Rpkx Rvkx I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 499 X E D N I FCP recommendations Roughness [µm] Rpkx Rpk Rk Mr1 Abbott-Firestone curve Rvk Rvkx Mr2 * ** Carbides: WC/Ni, Cr2C3/NiCr Ø porosity: < 0.5 % Typical layer thickness: 125 µm Ceramic: Al2O3, Cr2O3 Ø porosity: < 3 % Typical layer thickness: 200 µm *** Nitrocarburizing, induction hardened 0 10 20 30 40 50 60 70 80 90 100 Mr [%] Fig. 246 Recommendations for the quality of counter surfaces in tribological systems – Last updated Q4/2021 Map-marker-edit Characteristic values for surface assessment The material peaks determined by this characterization are responsible for the abrasive properties and the wear potential. The depressions allow oil deposits and are relevant for the medium transport, possible leakage and for the hydrody- namic lubricating film. The so-called pro- file core, in turn, is significant for the long- term behavior. Freudenberg Sealing Technologies has developed a pioneering FCP concept (FCP = Freudenberg Counter Surface Parame- ters) and defined limit values that provide information on the suitability of a surface as a partner in a tribological system. → Fig. 246 shows the current status at the time of publication of suitable surface pa- rameters for the new generation of high velocity flame sprayed (HP-HVOF) or laser cladding surfaces, for ceramic coatings, for hard chrome plated surfaces and thermo- chemical processes. In the course of the current test series of FST, it has also been shown that for a description and evaluation of most sur- faces, the previous standard character- istic value R a and the two RK character- istic values Rpk and Rvk are sufficient. OUTLOOK Recent studies show a clear trend towards high velocity flame sprayed surfaces. Outstanding service life and best corro- sion protection with lowest porosity are the arguments compared to all other finishing processes. To fully exploit the advantages in the tribological system, the finishing of HP-HVOF surfaces is decisive, which requires the corresponding know- how of the coater. If such a surface com- plies with the limit values defined in → Fig. 39, which were developed by FST in cooperation with a renowned coater, amazing results can be achieved in com- bination with sealing materials:

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Seals for Fluid Power Applications – Hydraulics While PTFE variants, as expected, also show high functionality on HP-HVOF sur- faces, polyurethane in particular achieves excellent results. On comparatively smooth surfaces, PU seals demonstrate maximum functionality and virtually wear-free behavior in the endurance test. → Fig. 247 and Fig. 248 show a new seal, while → Fig. 249 and Fig. 250 show the result after an endurance test of 200 km (pressure: 25 MPa, speed: 0.25 m/s, tem- perature: +80 °C). The small extrusion flag in → Fig. 249 is evidence of the load during the endurance test. The sealing edge itself (→ Fig. 250) shows no appre- ciable signs of wear. This is a promising approach for future seal designs. Fig. 248 A T20 U-ring in new condition Fig. 247 The T20 sealing edge before the before the endurance test endurance test Fig. 249 The T20 U-ring after the endur- Fig. 250 The T20 sealing edge after the ance test endurance test 500

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7. PRODUCT PRESELECTION 7. Product Preselection 7.1 PRODUCT FINDER FOR SEALING SYSTEMS The following product finder is based on a systems approach. Ten standard sealing systems with ideal- ly matched individual components are suited to the tasks and requirements of a wide range of typical hydraulic applica- tions. PROCEDURE Application symbols and a superordinate characterization allow selection of a seal- ing system suitable for the given applica- tion, as a first step. In the second step, the typical application parameters and the most important properties of the sealing system can be used to verify the selection. Maximum values for the application parameters show the possible leeway should the planned or existing application condi- tions deviate. Data sheets – grouped per sealing system – and further literature available via QR code round off the selection. The described procedure for product preselection is target-oriented with re- gard to y standardization of sealing solutions y element interchangeability y economic efficiency/large series If the operating parameters, media or de- sign of the planned application deviate from the standards shown here, individ- ual adjustments to individual elements in the sealing system can ideally be made in consultation with the seal manufac- turer. The complete product overview starting on page 418 shows a wide range of other seals and guide elements to find suitable solutions for even the most challenging applications. The product overview also contains all designs for the spare parts market. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 501 X E D N I

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Seals for Fluid Power Applications – Hydraulics SEALING SYSTEMS – MOBILE HYDRAULICS EXAMPLE OF USE STANDARD SEALING SOLUTIONS DATA SHEETS 1. Low to medium load Product data sheets for sealing system * * PRW1 PU FRI PA T20 PU Simko 300 PU FRA PA 2. High load with medium duration of use Product data sheets for sealing system 3. High load with long duration of use Product data sheets for sealing system * * PRW1 PU T20 PU SB(K) HG OMS-MR (PR) PTFE OMK-MR KB(K) PTFE HG 4. High load with long duration of use Product data sheets for sealing system 5. Very high load with long duration of use Product data sheets for sealing system * * DMRW2 PU T20 PU SB(K) HG Syprim SM PU HDP 330 KB(K) PA HG * Check use of dirt/diesel rings if required 502 PRW1PUSB(K)HGSimko 300PUKB(K)HGHDR 2CPU**T20PUPRW1PUSB(K)HGSimko 300PUSyprim SMPUKB(K)HG**

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APPLICATION PARAMETERS TYPICAL (MAX.) VALUES PROPERTIES FURTHER SELECTION AIDS I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I 7. Product Preselection I & N O T C U D O R T N S E C I V R E S Z-Card material handling R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H Z-Card agriculture machinery 26 (40) MPa +80 (+100) °C 0.3 (0.5) m/s 32 (40) MPa +80 (+100) °C 0.3 (0.5) m/s for short housings without primary seal good drift behavior of the piston seal easy to install for high dirt loading: wiper DMRW2 for short housings without primary seal good drift behavior of the piston seal easy to install for high dirt loading: wiper DMRW2 32 (40) MPa best functionality with primary and secondary seal Z-Card construction machinery +80 (+100) °C 0.15 (1.5) m/s 32 (40) MPa +80 (+100) °C 0.3 (0.5) m/s 40 (60) MPa +100 (+110) °C 0.3 (0.5) m/s for low and high speed favorable friction behavior low stick-slip tendency high chemical resistance for high dirt loading: wiper DMRW2 best functionality with primary and secondary seal good drift behavior of the piston seal easy to install for high dirt loading: wiper DMRW2 best functionality with primary and secondary seal high performance materials suitable for ﬁnished drawn cylinder tubes easy to install Z-Card construction machinery Z-Card construction machinery S C I T A M U E N P R E W O P D U L F I – S N O T A C I I L P P A S L A E S C I T A T S G N I L A E S L A I C E P S C I L U A R D Y H S T C U D O R P S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P X E D N I 503

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Seals for Fluid Power Applications – Hydraulics SEALING SYSTEMS – HEAVY INDUSTRIAL APPLICATION EXAMPLE OF USE STANDARD SEALING SOLUTIONS DATA SHEETS 1. High speeds at medium load Cover Seal PU Cover Seal PU Product data sheets for sealing system PT1 PTFE T20 PU SBK HG OMS-MR PR PTFE KBK HG OMK-S PTFE 2. Typical plunger sealing solution Product data sheets for sealing system 3. Proven solution for harsh operating conditions Product data sheets for sealing system Cover Seal PU PU6 PU SF PTFE ES61 PTFE/NBR SBK HG KBK HG LF27 PTFE/NBR 4. Very high loads at high control frequency Product data sheets for sealing system 5. Very high load with long duration of use Product data sheets for sealing system Metallische Führung P6 NBR ES/ESV NBR/FKM/Gewebe EK/EKV NBR/FKM/Gewebe 504 T20PUP9NBRSBKHGCover SealPUOMS-S PRPTFEOMS-SPTFEPT2PTFESBKHGKBKHGO-Ring/BackringNBR/POMOMK-SPTFE

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7. Product Preselection APPLICATION PARAMETERS TYPICAL (MAX.) VALUES PROPERTIES FURTHER SELECTION AIDS I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I 26 (40) MPa +60 (+80) °C 1 (1.5) m/s 30 (45) MPa +80 (+100) °C 0.5 (1) m/s 30 (45) MPa +80 (+100) °C 0.3 (0.8) m/s high functionality with primary and secondary seal for high speeds with simultaneous long strokes and slim cylinders high number of cycles: > 5 million high functionality with primary and secondary seal suitable for large diameters, long strokes and high pressures different speeds/strokes with/ without load extending linearly downwards universal use in many applica- tions short design without primary seal, extremely robust high lateral forces possible with long strokes up to 10,000 mm large sealing gaps to avoid metallic contact +60 (+100) °C 0.3 (1.5) m/s 15 Hz 30 (40) MPa +80/+130 2) °C 0.3 (0.5) m/s compact seal arrangement minimal friction/wear PTFE glass gentle with best self-lubricating properties PT2 double wiper for extreme dirt accumulation and additional sealing function large extrusion gap possible durable sealing system even with heavily stressed rod/ surfaces good emergency running properties available in open version for easy, low-cost installation/service 8/28 1) (40) MPa Steel brochure Injection molding machine brochure Y R A T O R R O F S L A E S S N O T A C I I L P P A Industrial presses brochure R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Industrial presses brochure S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Steel brochure S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 1) Different pressure level at rod and piston sealing system 2) Typical when using FKM 505 X E D N I

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Seals for Fluid Power Applications – Hydraulics Within a material group, such as polyure- thanes, different application limits are possible. Extreme external factors or operating conditions, such as strong vibra- tions, contamination, aggressive media, high lateral forces, large differences in speed when the piston rod is retracted and extended, etc., can limit the performance data of seals and components. The interac- tion with the other elements of a sealing system is also of great importance. In this context, FST offers an intensive consulting (→ see also chapter “Services”, page 7). The evaluation of the other features within a group focuses on the strengths or characteristics of individual products in direct comparison with each other on the basis of typical practical applications. Extreme operating conditions, as men- tioned above, can distort the picture. Absolute comparisons with seals or elements from other manufacturers are therefore only possible to a limited extent. The primary focus shoud be on the indi- vidual conditions. The complete product overview starting on page 418 shows a wide range of oth- er seals and guide elements to find suit- able solutions for even the most chal- lenging applications. The product overview also contains all seal designs for the spare parts market. 7.2 PRODUCT FINDER FOR INDIVIDUAL COMPONENTS The following product finder is one of several tools for successful seal selection. The focus is on optimizing or adapting the functionality of an existing sealing system to the individual requirements of the application. For new housing designs, Freudenberg Sealing Technologies recommends the “holistic approach” to a sealing system described in → “7. Product preselection,” page 501. The selection of individual components is to be handled as follows: y within a product group, such as wipers or rod seals, a preselection is made on the basis of typical representatives of subgroups (e.g. specific material, appli- cation parameters) y a more in-depth analysis can be carried out via product or material data sheets. These can be accessed via the FST web- site or the respective QR code in the product overview (→ page 418) y designs that have found widespread use in a variety of applications and are also found in the FST standard sealing sys- tems are characterized accordingly Important: The performance data shown, such as pres- sure, temperature or speed, are primarily to be seen as limit ranges for the use of a ma- terial/design combination. The later, actu- al performance values are also dependent on the choice of material and the maxi- mum simultaneously occurring values of the mentioned performance parameters. 506

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5 0 7 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING 7 . P r o d u c t P r e s e l e c t i o n INTRODUCTION & SERVICES

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Seals for Fluid Power Applications – Hydraulics SINGLE COMPONENTS – ROD SEALS DIN/ISO Design 5597 ROD SEALS T20 NI300 LF300 HDR-2C Material PU PU PU PU [C°] 100 +120 100 +120 100 +120 200 200 200 Temperature Max. [m/s] Stroke speed 50 0 ‒50 ‒100 6 5 4 3 2 1 0 50 0 ‒35 ‒35 ‒50 ‒100 6 5 4 3 2 1 0 0.5 m/s 0.5 m/s 50 0 ‒50 ‒100 ‒50 6 5 4 3 2 1 0 0.5 m/s 200 100 50 0 ‒50 ‒100 +110 ‒50 6 5 4 3 2 1 0 0.5 m/s Max. [MPa] 45 45 45 45 Pressure Nominal dimens. [mm] 8 … 320 10 … 220 16 … 120 32 … 180 Suitability as a single seal Suitability as primary seal Suitability as secondary seal Pressure relief function Friction behavior Pressurization on both sides Special features Preferred design B – B – D – B B – – – D – B – B – C – B B – B – D – B very well suited B C well suited D – satisfactory not suitable –* Variant for double-sided pressure available 508

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7. Product Preselection 5597 ROD SEALS T23 NI150 NI250 KI310 KI320 SM I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H 50 0 ‒50 ‒100 6 5 4 3 2 1 0 ‒35 R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P 0.5 m/s S L A E S C I T A T S PU/POM 200 100 +120 PU/POM NBR NBR/POM PU PU/POM 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +110 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +110 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +110 ‒30 0.5 m/s 50 10 25 40 50 50 40 … 305 6 … 125 20 … 90 10 … 145 40 … 140 40 … 200 B – – – D – B – – – D – B – – – D – B – – – D – B – – – D – – B – B C – B G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 509 X E D N I

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Seals for Fluid Power Applications – Hydraulics SINGLE COMPONENTS - ROD SEALS DIN/ISO Design ROD SEALS OMS-MR (PR) OMS-MR DW OMS-S (PR) OMSU-MR (PR) Material PTFE PTFE PTFE PU [C°] Temperature Max. [m/s] Stroke speed 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 2 Max. [MPa] 40 40 40 40 Pressure Nominal dimens. [mm] 3 … 1.290 8 … 840 20 … 1.630 20 … 950 Special features Preferred design Suitability as a single seal Suitability as primary seal Suitability as secondary seal B B C Pressure relief function – (B) Friction behavior Pressurization on both sides B – B B – – – B B B B C B B C – (B) – (B) B –* B C –* very well suited B C well suited D – satisfactory not suitable –* Variant for double-sided pressure available 510

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7. Product Preselection ROD SEALS ES, ESV VPS40 NBR/FKM PU 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +140 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒20 0.5 m/s 40 40 12 … 1.220 80 … 2.200 B – D – D – B B – D – C – I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 511 X E D N I

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Seals for Fluid Power Applications – Hydraulics SINGLE COMPONENTS – PISTON SEALS DIN/ISO Design 7425 part 1 PISTON SEALS SIMKO 300 HDP330 OMK-PU OMK-MR OMK-E OMK-S Material PU PA PU PTFE PTFE PTFE [C°] Temperature Max. [m/s] Stroke speed 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 0.5 m/s +100 ‒30 0.8 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s +100 ‒30 0.5 m/s Max. [MPa] 40 60 25 40 40 40 Pressure Nominal dimens. [mm] Special features Pressurization on both sides Friction behavior Back-to-back layout Heavy duty applications Preferred design 20 … 200 27 … 200 20 … 200 8 … 1.330 8 … 950 50 … 1.750 B B – C B B D – B B B C – – B B – C B – B – C B B – B B very well suited B C well suited D – satisfactory not suitable –* Variant for double-sided pressure available 512

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7. Product Preselection 7425 part 1 5597 6547 5597 PISTON SEALS OMK-ES L27 T18 NA300 L43 NA150 NA250 EK, EKV PTFE PTFE PU PU NBR/TPE/PA NBR NBR NBR, FKM 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 °C ‒ 30 1.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 200 +110 100 +120 50 0 ‒30 ‒35 ‒50 ‒100 6 5 4 3 2 1 0 0.5 m/s 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 0.5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +140 ‒30 0.5 m/s 40 50 50 40 40 10 25 40 110 … 950 50 … 320 40 … 320 15 … 200 40 … 200 12 … 200 32 … 180 12 … 1.220 B B B B B C – B B – C B B B – C – C B B D – C – D – – – D – – – D B B B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 513 X E D N I

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Seals for Fluid Power Applications – Hydraulics SINGLE COMPONENTS – WIPERS DIN/ISO Design Material [C°] Temperature Max. [m/s] Stroke speed Nominal dimens. [mm] Special features Protective effect against coarse dirt Additional sealing lip/edge Pressure relief function at the additional sealing lip/edge Self-retaining with metal cage in axially open housing Installation in axially closed housings Preferred design 6195 Type A 6195 Type B 6195 Type A WIPERS PRW1 PU5 DMRW2 AU AS/AU ASR AU PS PU 200 100 +120 50 0 ‒50 ‒100 ‒50 6 5 4 3 2 1 0 1 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 PU PU 200 +110 100 +120 50 0 PU PU +110 200 100 50 0 +110 200 100 50 0 ‒30 ‒35 ‒30 ‒30 ‒50 ‒100 ‒50 ‒100 ‒50 ‒100 6 5 4 3 2 1 0 0.6 6 5 4 3 2 1 0 2 6 5 4 3 2 1 0 2 2 20 … 160 16 … 200 35 … 90 10 … 200 35 … 110 C B B – B B C – – – B B B B B B – B B – – B – B B – – B – B very well suited B C well suited D – satisfactory not suitable –* Variant for double-sided pressure available 514

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7. Product Preselection 6195 Type D 6195 Type A WIPERS PT1 PU1 PT2/PT2 PR PT4 AS ASOB P8 P9 PTFE PU PTFE PTFE NBR NBR NBR NBR 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +110 ‒30 1.5 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +200 °C ‒ 30 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 2 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 2 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +110 ‒30 1 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 1 10 … 1.125 10 … 1.125 100 … 1.600 20 … 400 6 … 240 8 … 140 10 … 1.000 200 … 2.450 C B – – B B C B – – B B B B B – B B D B – – B B D – – B – D – – – B D B – – B D B – – B B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 515 X E D N I

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Seals for Fluid Power Applications – Hydraulics SINGLE COMPONENTS – GUIDES DIN/ISO Design 10766 GUIDES SF/KF FRI/FRA SB/KB SBK/KBK Material PTFE PA (reinforced) Laminated fabric Laminated fabric [C°] Temperature Max. [m/s] Stroke speed Nominal dimens. [mm] Special features Behavior with asymmetrical load Friction behavior Load capacity Preferred design 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 °C ‒ 40 5 m/s 200 100 50 0 ‒50 ‒100 6 5 4 3 2 1 0 +100 ‒30 1 200 200 100 +120 100 +120 °C ‒ 40 5 50 0 ‒50 ‒100 6 5 4 3 2 1 0 °C ‒ 40 5 50 0 ‒50 ‒100 6 5 4 3 2 1 0 Roll goods 20 … 180 20 … 1.650 25 … 1.650 D B D B C C C B C C B B B C B B very well suited B C well suited D – satisfactory not suitable –* Variant for double-sided pressure available 516

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8. INSTALLATION OF HYDRAULIC SEALS 8. Installation of Hydraulic seals Careful, correct installation of a seal in the housing is decisive for its subsequent functionality and service life. Practical ex- perience shows that this connection is of- ten underestimated, and the resulting leaks or failures are initially attributed to a quality defect in the seal. However, in- depth analysis reveals that errors or lack of attention during installation are some of the most common reasons for prema- ture seal failure. The most important types of installation are presented below. All of them are preceded by optimal installa- tion preparation. This is the basis for the subsequent installation success. Video instructions for each type of instal- lation can be accessed online via QR codes (following pages) if required. Freudenberg Sealing Technologies offers comprehensive service and assistance with all questions relating to the installa- tion of seals. In addition, clarifying impor- tant installation aspects at an early stage during the design of a component can pre- vent subsequent complex installation of seals, including complex tools (see also → chapter “Services,” page 7). 8.1 OPTIMAL INSTALLATION PREPARATION Regardless of the type of installation select- ed, all seals are sensitive to foreign bodies and especially to sharp edges or burrs in the area of the housing and the counter surface. This also applies to tools that may be used for installation. THE FOLLOWING RECOMMENDATIONS APPLY y Deburr sharp edges of the housing and in the area of the counter sur- face, provide them with lead-in chamfers, bevels or radii and polish any transitions. This must be checked carefully before installation! y Edges of tools and installation aids should also be burr-free and rounded y If seals are pushed over keyways, threads and the like during installa- tion or come into contact with them during subsequent installation of the rod, these areas must be covered with suitable sleeves during instal- lation (→ Fig. 251) y Carefully clean all components be- fore installation y Depending on the seal and the type of installation, heating the seal (+80 °C to +100 °C; ideally in a heating oven or in the operating medium) can facilitate installation. For infor- mation on whether and how heat- ing can be considered, please refer to the respective installation in- structions for the seal type y Seals stored at minus temperatures should generally be warmed to above 0 °C in a suitable place before unpacking and installation y Sparing wetting of the seal or hous- ing, preferably with operating me- dium, can also facilitate installation. Details can be found in the respec- tive installation instructions y Seals sometimes work in a directional manner. Therefore, the correct orien- tation of the sealing element in the housing must be ensured I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 517 X E D N I

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Seals for Fluid Power Applications – Hydraulics Fig. 251 Suitable covering of grooves or threads during seal installation 8.2 INSTALLATION OF THE SEAL IN AN AXIALLY OPEN HOUSING The design of the housing determines the type of installation. Split or open housings allow very simple installation of seals (→ Fig. 252, bottom). The seal is pushed into an axially open groove. This is possible with both a rod and a piston seal. If the groove sits somewhat deeper in the housing, a sliding sleeve or mandrel can be used to help. A taper sleeve together with a slider facilitates the assembly of U-rings, espe- cially in the case of an unfavorable diameter-profile ratio and during series installation (→ Fig. 253). The cover or piston part is then installed and the housing is closed. 518

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8. Installation of Hydraulic seals Fig. 252 Undivided and divided (open) housing using the example of a rod sealing system Seals with metal cage or fabric reinforce- ment can only be mounted in split (open) housings. This can also be the case for very small sealing diameters with a large profile (→ Tab. 31). Seals with a certain degree of flexibility are suitable for snap-in installation in an undivided installation space (→ Fig. 252, above). These include U-rings or compact seals made of elastomer or PU materials as well as seals made of PTFE in combination with a preload element. Fig. 253 Installing a rod U-ring in an open housing using a cone sleeve and a slider (→ “Installation tool”, page 522) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 519 X E D N I

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Seals for Fluid Power Applications – Hydraulics SEALING TYPE Profile [mm] P = (D – d)/2 Minimum nominal Ø [mm] U-RINGS AND ONE-PIECE COMPACT SEALS MULTI-PART COMPACT SEAL E. G. OMEGAT 4 5 6 7.5 10 12.5 15 2.45 3.75 5.5 7.75 10.5 20 25 30 40 60 75 90 30 30 35 40 60 Tab. 31 Diameter limits for snap-on installation of rod seals depending on the seal profile The aim is to snap a piston seal into a groove by temporarily expanding it or by temporarily compressing or deforming the ring of a rod seal. Various methods are used for this, which are described below. 8.3 SELECTION OF THE INSTALLATION METHOD FOR SNAP-IN/-ON MOUNTING OF HYDRAULIC SEALS MANUAL INSTALLATION This simplest type of sealing assembly requires some skill and is only successful for gaskets without a metal cage or fabric reinforcement. For manual assembly, a rod seal is inserted on one side into a Finger Fig. 254 Inserting and pressing a U-ring into the groove of the housing by hand groove that is not too deep in the housing and then pressed completely into the groove with the fingers (→ Fig. 254). The same applies to the piston seal. The ring is hooked into the groove on one side and stretched over the piston so that it can snap completely into the groove. Alternatively, the three-finger method can be used for rod seals. In this case, the sealing ring is inserted into the housing in a kidney-shaped deformation and in- serted directly into the groove (→ Fig. 255). This type of installation is suitable for a large number of seal types if the housing/diameter is large enough. Smaller diameters with unfavorable profile ratios limit this simple method of hand installation of seals. PLIERS INSTALLATION As an extension of the three-finger method, the use of mounting pliers is recommended for larger, stiffer seal profiles or for smaller diameters. The pliers with their three bolts replace the fingers, so to speak, and facilitates preforming of the sealing ring to the kidney shape (→ Fig. 256). Seals without fabric reinforcement or without a metal cage are suitable for pliers instal- lation. Play-circle  Installation video manual installation Play-circle  Installation video pliers installation 520

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8. Installation of Hydraulic seals Fig. 255 Installing a rod seal using the Fig. 256 Installing a rod seal with the three- finger method mounting pliers Fig. 257 Installing a piston seal with the aid of mounting strap Fig. 258 Calibrating a PTFE sealing ele- ment after installation on the piston using a calibration sleeve Play-circle  Installation video mounting strap PTFE is not spontaneously elastic, but takes hours to return to its original shape. A conical calibration sleeve is used to calibrate the seal (→ Fig. 258). Due to the sometimes small bending radii and associated forces, this type of assem- bly is not recommended for PTFE seals. MOUNTING STRAP Mounting straps support the manual installation of piston seals and make it easier to slip the sealing ring over the piston (→ Fig. 257). The necessary stretching of a PTFE com- pact seal when it is installed on a piston must then be reversed in order to be able to continue with the assembly of the piston in a timely manner. This is because I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 521 X E D N I

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Seals for Fluid Power Applications – Hydraulics Play-circle  Installation video assembly tool rod seal INSTALLATION TOOL Installation tools are suitable for install- ing very small sealing diameters, particu- larly in conjunction with large profiles, for deep grooves in the housing, or for large series in general. These tools, which are generally made of plastic, are individually designed and tailored to the respective housing and seal type (→ chapter “Ser- vices – Installation and Deinstallation aids”, page 14). A typical set of installation tools consists of a conical mounting sleeve, a slider and, when installing a PTFE seal, also a cali- bration mandrel or calibration sleeve (→ Fig. 260). Play-circle  Installation video assembly tool piston seal When installing a piston seal, the ring is pushed over the mounting sleeve and stretched so that it can snap into the groove at the end of the sleeve (→ Fig. 259). Fig. 260 Assembly of a PTFE piston seal us- ing a conical mounting sleeve and a slider (expanding sleeve) In the case of a PTFE seal, as shown above for the mounting strap, a subsequent calibration with the aid of a calibration sleeve is required. Fig. 259 Typical installation tool (calibration mandrel, slider and conical mounting sleeve) for the installation of a PTFE rod seal. The picture also shows an exem- plary housing with a two-component Omegat seal 522

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8. Installation of Hydraulic seals In addition to the standard methods, other special installation methods are used. V-Packing Sets, for example, are some- times cut to the required dimensions directly before installation or can be installed open if required. Play-circle  V-Packing Sets Play-circle  Lip Packing Sets 8.4 DEINSTALLATION OF HYDRAULIC SEALS There is one basic rule for the deinstallation of hydraulic seals: Whenever work is carried out during the deinstallation of a seal, the protection or integrity of the housing has top priority. For this reason, a scriber, a suitable lever or a piercing tool are always applied directly to the seal. Reuse of a seal after deinstalla- tion is therefore almost impossible (ex- ceptions are, for example, open housings). If the housing is damaged, this leads to costly reworking or the functionality of a replacement seal used later can be con- siderably limited. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 523 X E D N I

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Seals for Fluid Power Applications – Hydraulics 9. SEAL FAILURE – PREVENTION AND DAMAGE ANALYSIS 9.1 INTRODUCTION Seals have the task of proving themselves in a tribological system against the spar- ring partners of the counter surface and the operating medium. Operating param- eters such as pressure, temperature, speed, but also, for example, vibrations, duty cycle or dirt in the environment have a significant influence on the functionality of a seal. Ideally, all influencing variables are known and defined, and the sealing system, in- cluding lubricant and counter surface, is optimally coordinated. If the seal is also installed with care, these are the best prerequisites for the longevity and trou- ble-free operation of a sealing solution. The reality is often different. Damage to and failure of seals are primarily caused by errors during installation, unforeseen influences during operation and, in par- ticular, by the interaction of influencing variables. Although a quality defect in the seal cannot be ruled out in the event of damage, it tends to be the exception. This section provides an overview of possi- ble causes of damage to seals. In addition to typical damage patterns, the short de- scriptions already contain tips for suitable remedial measures. See also → chapter “Services – Damage Analysis”, page 16. Comprehensive, more detailed informa- tion can be found in the VDMA Damage Atlas. This section and the VDMA Dam- age Atlas provide initial guidance. In the event of seal failure, however, neither of these can replace open discussion between the equipment operator, the equipment designer and the suppliers of media and seals. 9.2 TOOLS/METHODS OF DAMAGE ANALYSIS VD I Directive 3822 has proven its worth for carrying out a damage analysis. It systematically explains the path from the damage pattern to the damage mecha- nism, the cause of the damage and meas- ures for damage prevention. This is done in eight steps: Damage description General assessment Damage hypothesis Instrumental analysis Interpretation of results Cause of damage Correction of the cause of damage Damage report Fig. 261 The eight steps of damage analysis 1. Damage description The first step is to describe what hap- pened, which parts failed, when and how often. Is it a single failure or are parts from a delivery lot affected? In addition, the question is clarified whether the damage can be related to a good part. Finally, the operating conditions are de- scribed. 2. General assessment In this step, all information on the circum- stances of the damage is evaluated. The view expands to possible other failures in the vicinity or to other machine parts that have failed, as well as their description. 524

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9. Seal Failure – Prevention and Damage Analysis 7. Correction of the cause of damage The most important goal is to eliminate the cause of the damage. There are several ways to do this, depending on the type of cause. A modified installation technique may be sufficient to achieve this goal. Faulty media (e.g. water and/or air or dirt particles in the lubricant) can often be corrected quickly. More complex are, for example, cooling measures to protect against thermal overload, ad hoc changes to poor surfaces of the sliding partner, or correction of the design of the housings, for example to prevent extrusion of the sealing element. 8. Damage report The final damage report records the results of the first seven steps. It includes all in- formation on the damage, the results of the analyses and the conclusive correla- tion to the cause of the damage. The re- sult is the confirmation of the damage hypothesis including a clear description. 3. Damage hypothesis Based on the descriptions and initial as- sessments of the failed parts, a damage hypothesis is created. The damage pat- tern is the result of a mechanism induced by the cause of damage. 4. Instrumental analysis What exactly is seen? Here, a macro-micro- scopic, analytical analysis takes place (phys- ical, chemical) as well as an interpretation of what is seen (→ chapter “Services – Damage Analysis”, page 16). 5. Interpretation of results First conclusions can be drawn from the observations and results of the analysis. In addition, an attempt is made to find a clear description of the mechanism(s) that led to the damage. 6. Cause of damage The cause of damage is determined on the basis of a correlation between the ex- amination results, the damage pattern and the application. The damage pattern enables the analysis of which mechanism led to the damage. The primary goal is to find out which cause is responsible for this damage mechanism. The following, typical causes are possible: y thermal overload y climatically induced overload y chemical overload y mechanical overload y tribological overload y material defect y process error y design error Cause-effect diagrams, such as Ishikawa or fishbone diagrams, support this process step. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 525 X E D N I

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Seals for Fluid Power Applications – Hydraulics A caliper gauge and a microscope should be available for analyzing damage and ex- amining a seal. If chemical incompatibil- ity is suspected, it is helpful to have ac- cess to a laboratory. There, for example, it is possible to carry out storage tests to determine undesirable interactions be- tween the seal material and the medium in question. If the absorption mechanism predomi- nates, the seal material swells. If the ex- traction is higher, the sealing material shrinks. In both cases, a change in volume can lead to a change in the physical or mechanical properties of the material. A typical manifestation of this is a change in hardness and, as a result, a change in tensile strength or tear strength. PHYSICAL EFFECTS These change the mechanical properties of the seal material and are a direct con- sequence of its structural change. A distinction is made between two main mechanisms of physical action: CHEMICAL EFFECTS A chemical reaction occurs between the seal material and the operating medium or other environmental influences. This results in further crosslinking or chain scission or chain degradation at the mo- lecular level (→ Fig. 262). 1. Absorption of the operating medium by the seal material 2. Extraction of the soluble components (especially the plasticizers) from the seal material Here, too, the result is a structural change and thus a change in the mechanical properties of the sealing material (→ chapter “Materials and process engineer- ing – 9. Damage analysis”, page 163). Operating medium Light UV rays Oxygen Ozone Chain degradation (stress loss) Additional cross-linking (embrittlement) Polymer molecule (Rubber molcule) Crosslinking points Fig. 262 Chemical reaction of the seal material with the operating medium and envi- ronmental influences 526

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9. Seal Failure – Prevention and Damage Analysis 9.3 TYPICAL DAMAGE TO SEALS AND RELATED CAUSES AIR IN THE HYDRAULIC MEDIUM Air in the hydraulic medium is one of the most common causes of damage. Insuffi- cient venting of the system prior to com- missioning or an unsuitably positioned vent hole are the main reasons for this. Unfa- vorable operating conditions, such as local pressure drop in the hydraulic medium due to increased flow velocity, also intensify this effect by drawing in secondary air. The hy- draulic medium itself can also contribute to this. Aging successively reduces the air separation capacity of the medium. Bubbles form on the surface and the ma- terial structure is destroyed. Flow erosion (1) During the transition from the pressure side to the non-pressure side, the gas bubbles relax and entrain oil at high flow velocity. Diesel effect Flow erosion (2) If the pressure in the hydraulic system rises at high speed, air bubbles in the oil will be strongly heated. Spontaneous ignition of the gas-air mixture is possible. High proportion of dissolved air in the oil, which forms erosive bubbles along the seal due to pressure reduction. Explosive decompression Under pressure, gas penetrates the sealing material. If the pressure is rapidly reduced, the gas that has penetrated expands. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 527 X E D N I

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Seals for Fluid Power Applications – Hydraulics GAP EXTRUSION Due to a variety of influencing factors, gap extrusion is one of the most common causes of damage to a hydraulic seal: PU U-ring y design of the gap dimensions y tube expansion y drag pressure in the area of metallic guides y guides in general y hydraulic medium (lubrication proper- ties, frictional energy, shear forces in the area of the contact zone, aging condition) y seal material (mechanical properties, resistance) y operating parameters (pressure, tem- perature, cycle time, dwell time, heat dissipation, radiant heat) The following figures show the damage to different seal types: PTFE profile ring The material extruded under pressure into the extrusion gap is sheared off. Due to high operating temperatures, the damage occurs earlier with the same operating parameters. The material extruded under pressure into the extrusion gap is sheared off. Due to high operating temperatures, the dam- age occurs earlier for the same operating parameters. V-Packing Set The rubber/fabric pressure ring penetrates the extrusion gap under pressure. The fabric round wrap tears opens in the process, and pieces of rubber/fabric are completely separated. Sealing system Hydrodynamic pressure build-up Extrusion Extrusion In the absence of pressure relief, the hydrodynamic pressure build-up in the in- terspace caused by drag oil can destroy the secondary and even the primary seal by extrusion. 528

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9. Seal Failure – Prevention and Damage Analysis TWISTING A typical cause of damage to O-rings is twisting, which can be promoted by im- proper installation. Due to rolling during installation, the O-ring is already twisted in the housing groove. The following design and operating parameters increase the twisting of an O-ring: y eccentric position y out-of-roundness y high surface roughness y alternating pressurization With increasing twisting and thus in- creasing tension on the surface of the O-ring, the material cracks in the typical, spiral manner. FOREIGN BODIES IN THE HYDRAULIC MEDIUM This is a cause of damage that can be caused by inadequate cleaning of the metal parts during assembly. Other possible causes of foreign body contamination: y defective base material y defective coatings y metallic contact of the counter surfaces due to poor, defective guide elements Typical damage pattern (scoring, break- outs) caused by foreign bodies using the example of a PTFE profile ring. CRACKING A typical cause of damage is improper storage of the seal due to high operating temperatures over a long period of time or chemical attack of the seal material. O-ring Improper storage, chemical attack. Sealing edge of a shaft seal Excessive frictional heat, e.g. due to ex- cessive circumferential speed. Chemical attack with subsequent hardening of the sealing edge. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 529 X E D N I

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Seals for Fluid Power Applications – Hydraulics PU U-ring PU U-ring Temperature too high for a long period of time. DISSOLUTION/DECOMPOSITION (HYDROLYSIS) A typical damage pattern of a non-hydro- lysis-resistant sealing material in contact with water. High temperatures accelerate the decomposition process. PU U-ring Severe damage to the sealing ring due to hydrolysis in conjunction with high tem- perature. HEAVY WEAR OF THE SEALING EDGE The possible causes of increased wear are manifold: y unsuitable or too rough counter surface y deficient lubrication y high pressure Shaft seal Chemical attack by water or by an exces- sively high water content in the operating medium. Typical pattern of excessive wear: sealing edge becomes a wide tread and shows a strong groove formation. 530

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9. Seal Failure – Prevention and Damage Analysis Here, radial grooves distributed around the circumference of the PTFE sealing element clear the way for the hydraulic medium in good time in the event of a rapid increase in pressure. In general, the appropriate measure to remedy the fault depends not only on the type but also on the condition of the seal and/or the design of the housing. There should always be a comprehensive analy- sis of the situation at hand. Map-marker-edit Troubleshooting measures U-ring with back-up ring Heavy erosion due to an excessively rough counter surface U-ring Complete removal of the sealing edge due to an excessively rough counter surface. BLOW-BY EFFECT This type of damage does not affect the seal itself, but refers to a failure of the sealing function. It can be observed in PTFE compact seals. The system pressure normally activates an O-ring, which transmits the pressure to a PTFE profile ring and thus produces the desired sealing effect. Very rapid pressure increases and/ or expansion of the cylinder wall can dis- rupt this functional principle of the seal. In this case, the O-ring is not activated in time, so that the hydraulic medium passes by underneath the sealing edge. The mode of action of the blow-by effect is illustrated by the example of a PTFE pis- ton seal → Fig. 263. The fourth figure shows a common remedial measure by us- ing a seal type suitable for this application. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 531 X E D N I

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Seals for Fluid Power Applications – Hydraulics Cause Malfunction P P Profile ring Profile ring O-ring 1. Rapid increase in pres- sure and/or expansion of the cylinder wall 2. Medium penetrates the sealing gap and displaces profile ring Effect Remedy P P Radial groove 3. Medium blows through – blow-by effect 4. Pressure can reach/activate the O-ring in time via radial grooves Fig. 263 Mode of action of the blow-by effect using the example of a PTFE piston seal 532

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10. Special Seals 10. SPECIAL SEALS FORSEAL FOI/FOA MADE OF PTFE APPLICATION Hot water valves, pneumatic cylinders (FOI), hydraulic cylinders (FOA) PRODUCT DESCRIPTION U-ring-type seal made of PTFE with me- chanical tension spring. MATERIAL PRODUCT ADVANTAGES y Axially moving rod/piston seal (FOI/ FOA), can be used in axially open O-ring installation spaces (ARP568, MIL-P-5514) y Extreme media and temperature resistance y Good dry running properties y Low static and dynamic friction val- ues MATERIAL DESCRIPTION SPRING Carbon-filled PTFE PTFE F56110 Stainless steel as standard (material no. 1.4310) APPLICATION MATERIAL TEMPERATURE PRESSURE GLIDE SPEED SCOPE RANGE [°C] [bar] [m/s] PTFE F56110 + 1.4310 ‒200 … +260 30 PTFE F56110 + spring Hastelloy C276 (on request) ‒200 … +260 30 Rotary and pivoting motions possible. No rotation. Hydraulic fluids; oil; water; steam; air; solvents; pharmaceutical goods; foodstuffs or all media that do not attack PTFE and stainless steel Aggressive acids and alkalis 15 15 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O I T A C I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 533 X E D N I

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Seals for Fluid Power Applications – Hydraulics SURFACE QUALITY ROUGHNESS Ra [µm] Sliding surface FOI Sliding surface FOA Groove ≤ 0.4 ≤ 0.4 ≤ 1.6 Rmax [µm] 0.5 … 2 0.05 … 2 ≤ 10 Load-bearing capacity Mr > 50% up to max. 90% with depth of cut c = Rz/2 and reference line C ref = 0% DESIGN NOTES Dimensions available from Ø 10 mm (pis- ton)/Ø 5 mm (rod) up to approx. 2,000 mm. In general, installation is only possible in split, axially accessible grooves. Installa- tion in half-open grooves possible in ex- ceptional cases. INSTALLATION Careful installation of the seal is a pre- requisite for the proper functioning of the seal. 534

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S E A L S F O R P N E U M A T I C S I F L U D P O W E R A P P L I C A T I O N S – 5 3 5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS I S E A L S F O R F L U D P O W E R A P P L I C A T I O N S – P N E U M A T I C S INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Seals for Fluid Power Applications – Pneumatics TABLE OF CONTENTS 1. PRODUCT OVERVIEW 1.1 Rod seals 1.2 Piston seals 1.3 Damping seals 1.4 Precision profiles 2. PNEUMATIC COMPONENTS 2.1 Requirements 2.2 Features 2.3 Areas of application 2.4 2.5 Use of pneumatic seals Application examples 3. PRODUCT FINDER 4. SEALING MECHANISM AND INFLUENCING FACTORS 4.1 4.2 4.3 Tribological analysis of the sealing system Conservation of lubricant films by sealing lip geometry Prevailing friction conditions Installation spaces and guides Surface finish Media for pneumatic cylinders and valves Compressed air Lubricants for pneumatic cylinders and valves 5. INSTALLATION OF PNEUMATIC SEALS 5.1 5.2 Insertion chamfers on rods and pipes Installation of pneumatic seals 538 538 542 550 552 554 554 554 555 556 556 562 566 567 567 570 571 572 574 574 576 578 578 580 536

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5 3 7 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING T a b l e o f C o n t e n t s INTRODUCTION & SERVICES

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Seals for Fluid Power Applications – Pneumatics 1. PRODUCT OVERVIEW 1.1 ROD SEALS DESIGN DESCRIPTION MAIN APPLICATIONS NIPSL This seal is designed for axially open installation spaces and is supported by means of a round wire snap ring Pneumatic cylinders AU NIPSL This seal does not require an addi- tional element (snap ring) for axial fixing in the installation space and is easy to install. The material is characterized by a wide range of applications and high wear resist- ance. Very robust design for long running times – even with coarser tolerances Pneumatic cylinders (also large diameters) NIPSL 200 Compact seal with low space requirement Pneumatic cylinders (small diameters) NIPSL 210 NIPSL 300 NIPSL 310 Very compact seal with minimal space requirement. In combination with the right type of grease also suited for high temperature appli- cations Compact sealing element with a low space requirement. The material is characterized by good low-temperature properties and high wear resistance Very compact sealing element with a very low space requirement. The material is characterized by good low-temperature properties and high wear resistance Compact cylinder; short stroke cylinder Pneumatic cylinders (small diameters) Compact cylinder; short stroke cylinder PRODUCT GROUP Multifunctional seals 538

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 72 NBR 708 ‒20 … +100 On request 75 FKM 595 ‒5 … +150 Yes No Further information on our product portfolio 94 AU 21200 ‒30 … +90 Yes Yes 80 NBR 4005 ‒20 … +100 Yes On request 75 FKM 181327 ‒5 … +150 Yes On request 85 AU 20991 ‒30 … +80 Yes On request 85 AU 20991 ‒30 … +80 Yes On request I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 539 X E D N I

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Seals for Fluid Power Applications – Pneumatics PRODUCT GROUP Multifunctional seals Compact seals DESIGN DESCRIPTION MAIN APPLICATIONS NIPSL 320 Very compact seal with a minimal space requirement. The material is characterized by good low-temper- ature properties and high wear resistance Compact cylinders (in- cluding larger diameters) AIRZET PR Double acting seal that enables short cylinder covers. The rounded sealing profile and flexible center section result in good sealing per- formance with low friction and the maintenance of an effective lubricating film. The materials c over a wide temperature and media range, yet offer good wear resistance Cylinders and valves 540

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 94 AU 925 ‒30 … +90 Yes Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P 80 NBR 186349 ‒20 … +100 75 FKM 230553 ‒5 … +150 Yes On request S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 541 X E D N I

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Seals for Fluid Power Applications – Pneumatics 1.2 PISTON SEALS DESIGN DESCRIPTION MAIN APPLICATIONS PRODUCT GROUP U-cup seals NAPN Proven, robust design – wide range of sizes available Pneumatic cylinders NAP210 Very compact U-cup with a minimal space requirement Pneumatic cylinders and valves NAP300 NAP310 Airzet PK Tried and tested, robust design with a wide range of available sizes. The material is characterized by good low-temperature properties and high wear resistance Very compact U-Cup with a minimal space requirement. The material is characterized by good low-temper- ature properties and high wear resistance Double acting seal with grooves on the side faces for pressure activation. The compact design allows very short pistons. The rounded seal profile and the flexible center section ensure good sealing with low friction and allow an effective lubricating film to be maintained over a long period. The materials used cover a wide temperature and media range, with good wear resist- ance at the same time Pneumatic cylinders Pneumatic cylinders Pneumatic cylinders; short-stroke cylinders; valves Compact seals 542

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 80 NBR 186349 ‒20 … +100 On request 75 FKM 595 ‒5 … +150 80 NBR 99079 ‒25 … +100 75 FKM 99104 ‒5 … +150 Yes Yes Yes On request 80 AU 20994 ‒35 … +80 Yes Yes 80 AU 20994 ‒35 … +80 Yes On request 80 NBR 186349 ‒20 … +100 75 FKM 230553 ‒5 … +150 Yes On request I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 543 X E D N I

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Seals for Fluid Power Applications – Pneumatics DESIGN DESCRIPTION MAIN APPLICATIONS KDN Double acting seal with symmetri- cal design. Refer to product line PNEUKO G as well Compact cylinders; short stroke cylinders; valves TR200 NADUOP Double acting seal, radially floating in the installation space, with grooves on the side faces for reliable pressure activation. Low, almost time-independent, constant friction. Smooth running even at very low speeds. Optimal usable stroke due to very narrow installa- tion space. Thanks to the completely symmetrical design, there is no need to pay attention to position orientation during assembly. FKM seals for high tem- perature applications and critical media Double-acting one-piece piston with a steel body, vulcanized sealing lips with a special pneumatic sealing edge and impact buffers for mechan- ical end-position cushioning. Radial ventilation channels allow rapid pressurization in the end positions. Ready-to-install, alternately pres- surizable complete piston with an integrated guide. In combination with the right grease, FKM can also be used for high-temperature appli- cations Pneumatic cylinders; short stroke cylinders; valves; special applica- tions (on request: seals made of FKM for high temperature applications and critical media) Compact cylinders and short-stroke cylinders without position sensing PRODUCT GROUP Compact seals Low-friction seals Complete pistons 544

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 72 NBR 708 ‒20 … +100 Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H 72 NBR 708 ‒20 … +100 On request 75 FKM 230553 ‒5 … +150 72 NBR 708 ‒20 … +100 On request 75 FKM 595 ‒5 … +150 R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P Yes On request S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A Yes No S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 545 X E D N I

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Seals for Fluid Power Applications – Pneumatics DESIGN DESCRIPTION MAIN APPLICATIONS TDUOP TDUOP Air PNEUKO G PNEUKO M210 PNEUKO M310 Double-acting, one-piece complete piston consisting of a steel body and vulcanized sealing lips with special pneumatic sealing edges. Guiding function for moderate lateral forces included. Simple mount ing, no separate static seal required. The TDUOP Air is equipped with radial ventilation chan nels on the side faces for faster pres surization in the end position. For high- temperature applications FKM in combination with a suitable grease is recommended Double-acting, very compact piston consisting of an aluminium body**, KDN piston seal, APR static seal and integrated guide made of polyamide. (** Note: sizes Ø 12 to Ø 25 mm piston entirely made of POM). Ready-to-install, space saving design with static seal included Double-acting, compact piston assem bly consisting of lightweight alu minum bodies, FRA guide ring, integrated magnet for position sensing and sealing elements with a special pneumatic sealing edge on the dynamic sealing lip as well as integrated stop buffers for me- chanical end-position cushioning Ready-to-install with static seal included. The FKM version PNEUKO M210 can also be used for high- temperature applications in combi- nation with a suitable grease Pneumatic cylinders without position detec- tion Pneumatic cylinders without position detec- tion; special cylinders Short-stroke, compact and ISO pneumatic cylinders with position detection PRODUCT GROUP Complete pistons Piston assemblies 546

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 72 NBR 708 ‒20 … +80 On request 75 FKM 595 ‒5 … +150 72 NBR 708 ‒20 … +80 On request 75 FKM 595 ‒5 … +150 Yes Yes Yes Yes No No No No 72 NBR 708 ‒20 … +100 Yes No 75 FKM 181327 ‒5 … +150 Yes No 85 AU 21030 ‒30 … +80 Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 547 X E D N I

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Seals for Fluid Power Applications – Pneumatics PRODUCT GROUP Piston assemblies DESIGN DESCRIPTION MAIN APPLICATIONS TDUOP M Double-acting, complete piston consist ing of aluminum base bodies with a vulcanized sealing contour, FRA guide ring and a magnet for position detection. Special pneumat- ic sealing edges ensure good sealing and maintenance of the lubricant film over a long period. Easy attach- ment to the piston rod, no addition- al static seal needed Pneumatic cylinders with position detection 548

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 72 NBR 708 ‒20 … +80 Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 549 X E D N I

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Seals for Fluid Power Applications – Pneumatics 1.3 DAMPING SEALS DESIGN DESCRIPTION MAIN APPLICATIONS D&S 300 DIP AU DIP Patented cushioning element for the cylinder end caps that fulfills several functions: static sealing be- tween the end cap and the barrel, pneumatic cushioning, material damping at the end of the piston stroke, and integrated check valve function. Significantly reduced number of components greatly simplifies machining of the cylinder end caps. Minimized noise emissions and dynamic stresses for cylinder components and adjacent devices DIP seals feature bypass channels on the outer circumference and on the piston side. Thanks to the inte- grated check valve func tion and automatic centering, relia ble pneu- matic cushioning and rapid start from the end position are achieved. For high-temperature applications an FKM variant is available and should be used in combination with a suitable grease AU DIP seals feature bypass chan- nels on the outer circumference and on the piston side. Thanks to the integrated check valve func tion and automatic centering, relia ble pneumatic cushioning and rapid start from the end position are achieved. The materials used are characterized by good low-temper- ature properties and high wear resistance Pneumatic cylinders; short stroke cylinders Pneumatic cylinders Pneumatic cylinders PRODUCT GROUP Damping seals 550

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 85 AU 21030 ‒30 … +80 Yes No 90 NBR 109 ‒30 … +100 On request 75 FKM 595 ‒5 … +150 85 AU 20991 for Ø ≤ 12 ‒30 … +90 94 AU 925 for Ø > 12 ‒30 … +90 Yes No Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 551 X E D N I

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Seals for Fluid Power Applications – Pneumatics 1.4 PRECISION PROFILES PRODUCT GROUP Precision profiles DESIGN DESCRIPTION MAIN APPLICATIONS Dust guard profiles Pressure sealing strips Sealing profile made of high-grade polyurethane with/without inte- grated micro ropes for strain relief. Application-specific design accord- ing to the installation situation. PU profiles are wear-resistant, noise-reducing, versatile and resist- ant to a wide range of media Sealing profiles made of high- quality polyurethane with integrated micro ropes for strain relief. Application- specific design according to the installation situation. PU strips seal the longitudinal slot of rodless cylinders and serve as a counter surface for the piston seals. This combination achieves a long service life and smooth running behavior Rodless pneumatic cylin- ders; electric linear drives and linear measur- ing systems on machine tools Rodless pneumatic cylinders Dirt scraper profiles Scraper profile with/without fixing elements or micro ropes. Application- specific design accord- ing to the installation situation Telescopic covers on machine tools 552

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A Various polyurethanes in a hardness range from 80 Shore A to 98 Shore A ‒30 … +100 (depending on the material used) R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H No No R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P Various polyurethanes in a hardness range from 80 Shore A to 98 Shore A ‒30 … +100 (depending on the material used) No No Various polyurethanes in a hardness range from 80 Shore A to 98 Shore A ‒30 … +100 (depending on the material used) No No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 553 X E D N I

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Seals for Fluid Power Applications – Pneumatics 2. PNEUMATIC COMPONENTS Product catalog Freudenberg Sealing Technologies (here- inafter also abbreviated FST) offers a comprehensive range of piston and rod seals, wipers, guides, damping elements, sealing strips and dust guard profiles for use in pneumatics. The customer can choose from an exten- sive range of standard products in various materials according to the requirements of the application. In addition, FST offers individual solutions for customers. This may include specific product designs, tailored material selection and customized processes. 2.1 REQUIREMENTS y low frictional forces and a wide range of velocities y media: compressed gases and air y typical environment: automated manu- facturing systems y innovative solutions required 2.2 FEATURES y broad selection of sizes in the diameter range from 1 mm to 500 mm y specific material selection according to the application y solution for temperatures ranging from ‒40 °C to +200°C y cost-effective manufacturing processes oriented towards economic and techni- cal requirements Fig. 264 Sealing systems in pneumatic linear actuators, e.g. for opening and closing train doors 554

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2. Pneumatic Components 2.3 AREAS OF APPLICATION Pneumatic seals are used in actuators as well as in valves to control the flow of compressed air. In addition, FST offers solutions for the sealing of rodless cylin- ders with polyurethane sealing strips and other customer-specific solutions. Areas of application include: y general mechanical engineering y automation engineering y food processing and packaging industry y material handling y individual customer solutions for special applications, e.g. for hand guided power tools Play-circle  Sealing solutions for hammer drills and demolition hammers I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 265 Sealing solutions in pneumatic actuators and valves, e.g. in blowmolding systems 555 X E D N I

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Seals for Fluid Power Applications – Pneumatics 2.4 USE OF PNEUMATIC 2.5 APPLICATION SEALS EXAMPLES Orginally the study of pneumatics de- scribes the behavior of gases. Nowadays, the term “pneumatics” (derived from the Greek “pneuma”) primarily refers to the transport and control of energy by means of compressed air. Pneumatic drives and controls, which are increasingly used for mechanization and automation of production processes, consist primarily of valves and cylinders. In order to function safely, pneumatic devices require the sealing of pressurized air volumes. The pneumatic seals used for this purpose can be classified into cylinder and valve seals (→ Fig. 267). Usually valve seals are specificly designed to match the requirements of individual manufacturers. The core of a pneumatic drive is the actu- ator. For typical cylinder designs refer to → Fig. 266, → Fig. 268 and → Fig. 269. In pneumatic cylinder 1 (→ Fig. 266), AU NIPSL is installed in the rod end cap. It combines the function of wiper and rod seal. Complete Piston Pneuko M is attached to the end of the rod. It includes the func- tions of sealing, damping, bearing lateral forces and position sensing. AU DIP is installed in both cylinder caps to dissipate the kinetic energy at the end of the stroke. Alternative options are: ma- terial damping (buffer disks) or external shock absorbers. Combination seal AU NIPSL Complete piston seal Pneuko M310 Damper seal AU DIP Fig. 266 Pneumatic cylinder I 556 Damper seal AU DIP

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2. Pneumatic Components I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A PNEUMATIC SEALS CYLINDER SEALS VALVE SEALS LINEAR SEALING PROFILES ROD SEALS PISTON SEALS SEAT SEALS SLIDE SEALS SEAL TAPES INDIVIDUAL SEAL SINGLE ACTING SEAL COVER TAPES COMBINATION SEAL+ WIPER DOUBLE ACTING SEAL COMBINATION SEAL + WIPER + GUIDE COMPLETE PISTON DAMPING SEAL DAMPING SEAL STATIC SEALS STATIC SEALS Fig. 267 Classification of pneumatic seals R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 557 X E D N I

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Seals for Fluid Power Applications – Pneumatics Map-marker-edit Typical standard cylinder design Map-marker-edit Piston rod loose cylinder A standard cylinder design is shown in → Fig. 268. The rod is guided in a bushing made of metal or plastic and is equipped with a combined wiper-rod seal (combi- nation element AU NIPSL). The piston is sealed with two pneumatic U-cups (U-cup NAP300). A separate guide is ar- ranged between the U-cups. This is either a guide band made of PTFE or guide rings made of hard fabric, thermo- setting plastic or thermoplastic. An alternative is to use pistons made of plastic, which do not have a separate guide element. To detect the piston position of such cylinders, the piston is equipped with a magnet that activates a switch mounted on the outside of the cylinder barrel. O-rings provide the static seal between the cylinder barrel and the cylinder base cover and between the piston and the piston rod. The D&S 300, which in addition to static sealing also damps the piston pneumatically and mechanically, is a spe- cial case. In rodless cylinders (→ Fig. 269), no rod seal is needed. Damping at the end posi- tions is achieved in the same way as for the cylinder in → Fig. 266. The cylinder barrel is longitudinally slotted, a piston and a carriage are connected by a link that moves axially in this slot. Special solutions are required to seal this slot and the piston: y a polyurethane cover tape protects against external influences and closes the slot from the outside. y the polyurethane sealing tape seals the slot on the pressure chamber side, and y the piston seals must seal against the pipe, sealing tape and their transitions. Piston seals NAP300 Damping element D&S 300 Damping element D&S 300 Piston guide (e.g. FRA) Combination seal AU NIPSL Fig. 268 Pneumatic cylinder II 558

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2. Pneumatic Components Damping pin, round “Y” sealing profile Damper seal, round Cover tape Drive carriage Throttle screw, adjustable I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P Cylinder barrel, oval bore S L A E S C I T A T S Cylinder cover Buffer disk, oval Piston cap, with guide surface O-ring as static seal, oval Piston seal, oval Sealing tape with steel cable reinforcement Fig. 269 Rodless cylinder (Source: Emerson Automation Solutions - AVENTICS GmbH) The dynamic sealing of swivel blade cylinders is a challenge because of the complex geometry and requires specifically designed seals. From the wide variety of valve seals avail- able, a few examples have been chosen and are shown in → Fig. 270 to Fig. 272. The diagrams of the valves are greatly simplified to clearly show the mode of operation and the task of the valve seals. Both, sealing tape and cover tape, are guided through the carriage-piston unit during the stroke. In addition to the piston cylinders described above, there are also diaphragm cylinders for very small linear movements. Here the function of the piston is carried out by a diaphragm made of elastomer or plastic material. Swivel cylinders are used to generate a limited rotary movement. They can be designed either as double-acting cylin- ders, where a pinion is driven by a toothed section of the piston rod or as a swivel blade cylinder. G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 559 X E D N I

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Seals for Fluid Power Applications – Pneumatics A R P Fig. 270 Quick-exhaust valve The quick-exhaust valve shown in → Fig. 270 is used to increase the piston speed in cylinders. The main features are the cup-like design of the seal and the elastic sealing material. When pressure is applied at port P, the seal closes exhaust port R and releases the path to A via the flexible lips. If there is no pressure at port P, the exhaust air from the cylinder enters at port A and can take the short path via R to the atmosphere. The 5/2-way valve in → Fig. 271 is used to control a cylinder. The left-hand illustration shows the position of the spool as long as the actuator piston is not pressurized: the spool is held axially in the upper po- sition by a spring. The operating pressure is always applied to port 1P on the right- hand side of the valve. In the position shown, the pressure is passed through to port 2B. Ports 4A and 5EA are connected to each other to vent the cylinder. Port 3EB is blocked. PE 5EA 1P 3EB 4A 2B PE 5EA 1P 3EB 4A 2B Fig. 271 Pneumatic 5/2-way valve 560

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2. Pneumatic Components 2B 4A PE1 3EB 1P 5EA PE2 Fig. 272 Pneumatic 5/2-way valve The illustration on the right shows the valve position with the actuator piston pressurized: the pilot valve at the upper end of the valve body allows compressed air to act on the piston, pushing the spool into the lower end position against the spring force. This connects or blocks oth- er openings. alternately by the pressure applied at ports PE1 and PE2 and maintains the position until the next impulse is applied. The seal in the center of the spool is used to release the flow either from 1P to 2B or from 1P to 4A. Ports 4A and 5EA or 2B and 3EB are connected together to vent the cylinder. In such a valve, pilot valve seals as well as actuator piston seals and control spool seals (6 pieces) are needed. Each of these seals requires an application-specific de- sign. An important factor for the operation of the 5/2-way valve in → Fig. 272 are the sealing/switching elements at the left and right end of the valve tappet. The design in conjunction with high perfor- mance polyurethane material ensures a long service life. The valve is actuated I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 561 X E D N I

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Seals for Fluid Power Applications – Pneumatics 3. PRODUCT FINDER Design Material [C°] Temperature Max. [m/s] Circumferential speed ROD SEALS NIPSL NIPSL 210 NIPSL 310 AU NIPSL NBR FKM FKM AU AU 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒20 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 ‒30 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +90 ‒30 1 m/s Max. [MPa] 1 1 1 1.2 Pressure Nominal dimens. [mm] 10 … 50 4 … 32 Special features Pressure > 12 bar C** C** Poka yoke assembly (no positional orientation of the seal necessary) Mounting in axially closed installation space Synchronization (low speed) Larger installation space tolerances Bidirectional pressurization Short axial installation space Low radial installation space High dirt accumulation outside Dirt accumulation Lubricated mating surfaces Medium Dry run D D C B D D C B C* D D D C B D D C B C* D D D B B D D B B B C* D 4 … 32 C** 12 … 50 C** D B B D D B B B C* D D D C B D D C B C* D C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable – not applicable 562

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3. Product finder ROD SEALS AIRZET PR PISTON SEALS NAP210 NAPN NAP300 NAP310 NBR FKM NBR FKM NBR FKM AU AU 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒20 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 °C ‒25 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒20 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 200 100 50 0 +80 ‒35 ‒35 ‒50 ‒100 50 40 30 20 10 5 0 1 m/s 1 m/s 1.2 6 … 50 1.2 1.2 1.2 1.2 8 … 100 6 … 320 25 … 160 8 … 200 C** B B B B B B D C* C* D D B B B B B B D C* C* D C* D B B C D B B – C* D D D B B C D B B – C* D C* D B C B D C C – C* D D D B C B D C C – C* D C* C* D B C B D C C – C* D D B B C D B B – C* D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 563 X E D N I

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Seals for Fluid Power Applications – Pneumatics Design Material [C°] Temperature Max. [m/s] Circumferential speed PISTON SEALS AIRZET PK TR200 NBR FKM NBR FKM 1) 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒20 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒20 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s Max. [MPa] 1.2 1.2 Pressure Nominal dimens. [mm] 12 … 160 12 … 125 25 … 125 Special features Pressure > 12 bar Poka yoke assembly (no positional orientation of the seal necessary) Mounting in axially closed installation space Synchronization (low speed) Larger installation space tolerances Bidirectional pressurization Short axial installation space Low radial installation space High dirt accumulation outside Dirt accumulation Lubricated mating surfaces Medium Dry run C* B B B B B B D – C* D D B B B B B B D – C* D C* B B B C B B D – C* D D B B B C B B D – C* D C* possible use, verification via individual endurance test C** possible use, verification necessary B well suited C conditionally suitable D not suitable – not applicable 564

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3. Product finder PISTON SEALS DAMPER SEALS NADUOP PNEUKO M310/M210 D&S 300 AU DIP NBR FKM AU FKM AU AU 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +100 ‒20 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 ‒30 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +150 °C ‒ 5 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +80 ‒30 1 m/s 200 100 50 0 ‒50 ‒100 50 40 30 20 10 5 0 +90 ‒30 1 m/s 1.2 1.2 2.5 2.5 8 … 100 On request 32 … 100 C* B – C B B B B – C* D 1) on request D B – C B B B B – C* D C* B – C B B C B – C* D 16 … 100 C** 8 … 50 C** D B B B B B – – C* D D B B B B C – – C* D D B – C B B C B – C* D I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 565 X E D N I

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Seals for Fluid Power Applications – Pneumatics 4. SEALING MECHANISM AND INFLUENCING FACTORS Whether it’s drive tasks, open-loop or closed-loop control: air plays a major role in engineering! Pressure in actuators and vacuum in handling devices can move, lift or retract workpieces and tools. Valves are being used to control the start and stop of acutators by directing the flow of pressurized air. No wonder that pneumat- ics still dominates in handling and auto- mation technology. There are three major requirements for pneumatic seals: y best possible tightness y low friction y long service life In case of elastomer seals without differan- tial pressure the sealing effect is ensured by sufficient contact pressure resulting from interference. Seal fitted in the installation space Seal compressed without differential pressure Contact pressure distribution as a result of interference pv Seal under pressure Contact pressure distribution as a result of interference and pressure to be sealed pd p pd p= + pv Fig. 273 Automatic sealing effect for elastic seals 566

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4. Sealing Mechanism and Influencing Factors The sealing pressure increases the basic compression. This means that the compres- sion between the seal and the mating sur- face is always greater than the operating pressure. This principle of operation, known as “automatic sealing effect”, is shown in → Fig. 273 using an O-ring as an example. To reduce friction and wear, it is neces- sary to use a lubricant that is able to with- stand very different conditions: ambient temperature, sliding speed, normal forces, etc. – a complex tribological system that places high demands on manufacturers of pneumatic drives. 4.1 TRIBOLOGICAL ANALYSIS OF THE SEALING SYSTEM The function and service life of a sealing system depend on many different oper- ating parameters (pressure, temperature, speed, etc.) as well as on the installation situation, seal geometry, materials, sur- face finish and lubricant used (→ Fig. 275). Friction describes the amount of energy lost as a result of a physical energy trans- fer. In the case of linear motion, it thus represents the resistance to motion in the form of a frictional force. This results from the interaction be- tween the sliding partners and from the resistance of the materials to deforma- tion during a movement or an intended movement. y Adhesive part of friction The surface activity and polarity of the respective sliding partners attract each other and thus generate a resistance that corresponds to the adhesive part of the friction (→ Fig. 275). y Deformation part of friction Macro- and micro-geometric interlocks cause plastic and/or elastic deforma- tion of the sliding partners. For manu- facturing reasons, the surfaces of two sliding partners will always have irreg- ularities that will affect each other dur- ing their relative movement. As a result of the deformation, energy losses occur that are caused by the hysteresis be- havior (damping) of the materials. y Liquid friction Due to the viscosity of the lubricants, there is a velocity-dependent increase in friction. CONSERVATION OF LUBRICANT FILMS BY SEALING LIP GEOMETRY The friction of elastomer seals depends mainly on the adhesion (sticking) of the contact points to each other, on the deformation of the sealing material at the contact points (hysteresis friction) and on the fluid friction (lubricant). In the case of elastic seals, the thickness of the lubricant film between the seal and the sliding surface depends mainly on: y the sliding speed y the dynamic viscosity of the lubricant y the pressure curve in the lubricant layer The pressure distribution can be influ- enced by the geometric design of the sealing lip. In general pneumatic seals and counter surfaces are lubricated for life at assembly. In order to maintain the lubricant layer for the service life of the device, pneumatic seals are equipped with a characteristic lip design. Map-marker-edit Influences on the function and service life of the sealing system Map-marker-edit Lifetime lubri- cation during assembly I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 567 X E D N I

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Seals for Fluid Power Applications – Pneumatics that both the seals and the mating sur- faces can be adequately lubricated. This ensures uni form wetting of all surfaces involved. Typical features are a flexible sealing lip and a defined radius of the sealing edge (→ Fig. 274). The resulting symmetrical distribution of contact pressure has a fa- vorable effect on the maintenance of the lubricant film and thus also on friction and wear. In contrast, hydraulic seals have the task of wiping off the medium effectively. Pneu- matic seals therefore differ significantly from hydraulic seals in terms of sealing lip geometry. Maximum cleanliness is required when applying lubricant during installation. The system must not be contaminated by machining residues, foreign particles or used lubricant. This is the only way Pneumatic seal Hydraulic seal Minimal wiping effect, lubricant film on mating surface over entire service life Strong wiping effect, high dynamic tightness. Oil (= pressure medium) must be retained in the pressure chamber. Flat contact pressure gradient, rounded sealing edge Steep contact pressure gradient, “sharp” sealing edge Fig. 274 Different lip geometry and pressure distribution with pneumatics and hydraulics 568

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4. Sealing Mechanism and Influencing Factors Tip for greasing mating surfaces Application of lubricants with fitted round brushes or automatic greasing by using lubrication pistons is a proven practice. Another option is automated spraying of the mating surface. It is important to ensure uniform distri- bution of the lubricant film and com- plete wetting of the sliding partners. Map-marker-edit Even distribution of the lubricating film and com- plete wetting are important Static sealing side Surface layers in contact Sliding speed Stroke frequency Cover Dynamic sealing side Friction temperature Housing material “Roughness” micro-geometry Medium to be sealed Dirt/water in the medium Installation space tolerance System pressure Seal geometry Seal material Ambient temperature Dirt from outside Counter surface Gap width Guide clearance Pressing and pressing behaviour Direction of motion Down time Lubricant Sliding surface Seal material I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Fig. 275 Basic influences on the tribosystem Adhesion friction Deformation friction Internal friction S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 569 X E D N I

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Seals for Fluid Power Applications – Pneumatics ] µ [ n o i t c i r f f o t n e c i f f e o C i H M F H = Static friction M = Semi-fluid friction F = Fluid friction Release point Lubricant Sliding surface Seal material Velocity [v] Static friction (H) Semi-fluid friction (M) Fluid friction (F) Normal Normal Normal Friction Velocity Friction Velocity Friction Velocity Fig. 276 Stribeck curve describes the dependency of the friction on the velocity y semi-fluid friction in this case, a relative movement takes place, which is impeded primarily by the fraction of micro-interlocking and adhesive friction as well as internal friction. The resulting friction force is generally lower than in case of static friction, because the intensity of the micro-interlocking is significantly less and the slide effect of the lubricant begins. With increasing velocity the fraction of micro-interlocking is re- duced, which lowers the friction. PREVAILING FRICTION CONDITIONS Different types of friction are generated by factors such as the sliding velocity of the friction partners relative to each other. The Stribeck curve shows the friction as a function of velocity. The friction states shown in → Fig. 276 are generated depend- ing on the sliding velocity: y static friction when a movement is imminent, the friction partners stick to each other due to micro-interlocking resulting from adhesive friction. The internal friction also acts as a resistance force against displacement of the micro-interlocking. There is no relative movement between the sliding partners. 570

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4. Sealing Mechanism and Influencing Factors Map-Marker-Exclamation No guiding tasks of the seal Individual seals are not designated to perform guiding tasks, except in the case of multi-functional elements. When using individual sealing elements, the guides should be designed in the fit tolerance H9/f9 unless separate guide elements (guide band made of PTFE or guide rings made of plastic) are used (→ Fig. 277). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P Map-marker-edit Installation space design S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P F7 Ø D1 ≤ Ø20 Ø D1 > Ø20 E7 Ø dN h8 C I L U A R D Y H S R O T A L U M U C C A y fluid friction when the sliding velocity gets sufficient- ly high, the viscosity of the lubricant gen- erates a pressure between the sliding partners, which completely separates the contact surfaces (like hydro-planing). The friction is primarily influenced by the operating parameters (pressure, temperature, velocity) and by internal friction components of the lubricant 4.2 INSTALLATION SPACES AND GUIDES The installation space for pneumatic seals should be designed in such a way that the seal can be easily installed and an optimal sealing effect is achieved during operation. H9 Ø D1 Ø dn f9 S W O L L E B & S T O O B H11 Ø DN Ø dK = DN – 0.6 Ø d1 d10 (metal) Ø d1 b10 (plastic) S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 277 Tolerances for guides 571 X E D N I

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Seals for Fluid Power Applications – Pneumatics SURFACE FINISH Friction and wear are significant factors for malfunctions in pneumatic cylinders. Freudenberg Sealing Technologies has developed a pioneering concept for the reliable assessment of sliding surfaces that takes into account the specific requirements of hard-soft contacts (→ Fig. 278). In the past, the parameters for metal- to- metal contacts have generally been used as the basis for evaluating mating surfaces for seals. However, since in fluid systems a piston and rod seal always represents a hard-soft contact, the result is only of limited value for evaluating the mating surface in terms of abrasion, long-term behavior and lubricant deposits. The result: higher friction and faster wear of the sealing elements in the tribological system. More reliability and longer service life With the new parameter recommenda- tions, surface profiles are recorded accord- ing to the proven profile method. Relevant parameters for a hard-soft contact are derived from the Abbott-Firestone curve (→ Fig. 282). The parameters defined there (→ Fig. 283) – core roughness depth Rk, peak height Rpk, Rpkx and groove depth Rvk, Rvkx – allow a fascinatingly precise de- scription of surfaces as mating surfaces for seals. This means that important properties of the surface topography can now be precisely determined in sealing technology: y the tips, which are responsible for the abrasive properties and wear potential y the profile core, which is responsible for the long-term behavior y the grooves influencing the medium transport (as leakage or hydrodynamic lubricating film) SURFACE RECOMMENDATIONS FOR MATING SURFACES Surface parameters R a dyn. R a stat. groove base Rz1max dyn. Rz1max stat. groove base Contact ratio Rmr dyn. Contact ratio Rmr stat. Rp/Rz Rz dyn./stat. groove base Rpk Rpkx Rk Rvk Rvkx Recommendations 0.05 ... 0.4 µm ≤ 1.6 µm ≤ 4 µm ≤ 10 µm 50 ... 75 % at 1 µm 50 ... 75 % at 1 µm < 0.5 0.6 ... 2.5 µm ≤ 0.5 µm ≤ 0.5 µm 0.25 ... 0.70 µm 0.20 ... 0.65 µm 0.20 ... 2.0 µm Fig. 278 Surface recommendations for mating surfaces 572

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4. Sealing Mechanism and Influencing Factors lt I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A Zt1 Zt2 Zt3 Rz1max Zt4 Zt5 R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H le lm = 5x le Pre-run section Run-on section Fig. 279 Determination of the surface value Rz R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P Profile tip area Metal Area of the profile valley Air Ra x S L A E S C I T A T S lm Fig. 280 Determination of the surface value Ra G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Rz = (1/5) (Zt1 + Zt2 + Zt3 + Zt4 + Zt5) → Fig. 279: Rz and Rz1max prove to be inconclusive parameters for the evalua- tion of mating surfaces for seals. Here, for example, Rz1max is dominated by a groove in the subsection 3 that is not critical in terms of tightness and wear. The strong abrasiveness in subsection 1 is not de- tected by this parameter. Rz as averaged roughness depth does not reveal this strong abrasiveness at Zt1 either. R a = (1/lm) lm ∫ | y(x) | dx 0 → Fig. 280: The arithmetic mean rough- ness R a has proven itself for the evalua- tion of surfaces for hard-hard contacts, but it is not meaningful for surfaces in hard-soft contact in sealing technology, because it is used to average peaks (metal) and grooves (air). → Fig. 281: The description of limit values for the wear components and the lubricant deposits in the surface profile as well as the definition of limit values for optimal long-term behavior is the key to an opti- mized tribological system consisting of the seal, the medium and the mating surface. Wear Long-term behavior Lubricant deposit Fig. 281 Interpretation of a surface topography for suitability as a mating surface of a seal S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 573 X E D N I

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Seals for Fluid Power Applications – Pneumatics Rpk Rk Rvk Balancing line Mr1 Mr2 Total measured distance Lt 0 20 40 60 80 100 Material content [%] Fig. 282 Extended surface characteristics based on the Abbott-Firestone curve Roughness [µm] Abbott-Firestone Curve Rpkx Rpk Rk Mr1 Rk 0.25 … 0.70 µm Rpkx 0.00 … 0.50 µm Rpk 0.00 … 0.50 µm Rvk 0.20 … 0.65 µm Rvkx 0.20 … 2.00 µm Rvk Rvkx Mr2 0 10 20 30 40 50 60 70 80 90 100 Mr [%] Fig. 283 Current state of the art of limit values 4.3 MEDIA FOR PNEUMATIC CYLINDERS AND VALVES COMPRESSED AIR Depending on the intended use, various compressed air quality classes are recom- mended in ISO 8573-1:2010. The criteria y solid particles y water y oil → Fig. 282: The material content curve (right) is derived from the surface profile (left). Here, the percentage of strong abrasivities as well as the percentage of grooves as possible lubricant deposits be- come visible. → Fig. 283: The FST parameters from the Rk group with Rpk, Rpkx, Rk, Rvk and Rvkx en- able an exact differentiation of abrasive- ness, long-term behavior and lubricant de- posits. are listed in ISO 8573-1:2010 tables in which the quality classes (Overview → page 575) are specified. In general, a distinction is made between treated and untreated compressed air. Untreated air is compressed with oil- lubricated compressors and only coarsely filtered. It still contains fine dirt particles, water and oil. To prevent premature wear of valves, cylinders and seals, particles larger than 40 µm should be removed by using ap- propriate filters. 574

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4. Sealing Mechanism and Influencing Factors PURITY CLASSIFICATION ISO 8573-1:2010, Class 1.2.1 ISO 8573-1:2010 refers to the standard document and its version. The three digits indicate the purity classification defined for solid particles, water and the total oil content. The purity class 1.2.1 indicates the following air quality for operation under the reference con- ditions of the standard: Particle Class 1 The number of particles per cubic meter of compressed air may not exceed 20,000 in the 0.1 to 0.5 micron range, 400 par- ticles in the 0.5 to 1 micron range, and 10 particles in the 1 to 5 micron range. Water Class 2 A pressure dew-point (DTP) of –40 °C or better is required. Water in liquid form is not permitted. Oil Class 1 A maximum of 0.01 mg of oil is permis- sible per cubic meter of compressed air. This value is the total content of liquid oil, oil aerosols and oil mist. Treated air is prefiltered after compression, dehydrated by refrigeration dryers (pres- sure dew-point +2 °C) and then purified in very fine filters. This air quality is frequent- ly referred to as “dried and oil free com- pressed air.” For particularly critical applications, the air can be dried again in an absorption dryer (pressure dew-point –60 °C up to –40 °C) after the fine filtering. Under ex- treme operating conditions “dried and oiled compressed air” is recommended for the pneumatic components. In these cases, a compressed air oiler is installed immediately upstream of the consumer. With the frequently encountered dried and oil free compressed air, the service life of the pneumatic seals depends greatly on the one-time initial lubrication. The lubricants must adhere well to the metal and elastomer surfaces. They must be compatible with the sealing material, offer high resistance to aging, good cor- rosion protection, a viscosity suitable for smooth running and be suited for use in the required temperature range. If oiled compressed air is used, the com- patibility between the lubricant and the oil is important for maintaining a stable lubricating film. Detailed information can be found in the device manufacturer’s manual. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 575 X E D N I

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Seals for Fluid Power Applications – Pneumatics LUBRICANTS FOR PNEUMATIC CYLINDERS AND VALVES LUBRICANT BASE OIL/THICKENING SUBSTANCE OPERATIONAL TEMPERATURE RANGE a) [°C] CA. DENSITY AT +20 °C DIN 51 757 [g/cm3] CA. BASE OIL VISCOSITY DIN 51 562 T1 [mm2/S] AT CA. +40 °C +100 °C Klübersynth AR 34-401 Synth. hydrocarbon oil/ special calcium soap –40 … +120 0.90 400 40 POLYLUB GLY 151 synth. hydrocarbon oil/ –50 … +130 0.85 150 18.5 Li special soap Mineral oil/ BARRIERTA L 55/1 PFPE/PTFE –40 … +260 1.95 415 Klüber synth UH1 14-151 Synth. hydrocarbon oil/ Al complex soap –40 … +120 0.92 150 Klüberbeta VR 87-883 Silicone oil/PTFE –40 … +160 – – 40 22 – PETAMO GHY 133N synth. hydrocarbon oil/ –30 … +160 0.88 150 18 Mineral oil/ polyurea UNISILKON L 641 N Silicone oil/PTFE –40 … +160 1.11 – – a) Operating temperatures are recommended values oriented to the lubricant composition, the specified use and the application technology. Lubricants change consistency depending on the type of mechanical-dynamic loading with the temperature, pressure and time, apparent viscosity and viscosity. The change in the characteristics of the product can influence the function of components. 576

577

4. Sealing Mechanism and Influencing Factors WALK PENETRATION DIN ISO 21 37 [0.1 mm] CONSISTENCY NLGI CLASS DIN 51 818 OTHER NOTES 310 … 340 310 … 340 310 … 340 310 … 340 220 … 250 265 … 295 – 1 1 1 1 3 2 – Adhering lubricating grease for high piston velocity ranges; reduced stick-slip tendency at very low piston velocity; low breakaway force even after extended downtime Light-running grease; also preferred for applications at low temperatures Adhering lubricating grease for high-temperature applications; very good resistance to most chemicals; good compatibility with most elastomers and plastics Approved by USDA H1, and designed for applications in the food industry; good water resistance and good corrosion protection USDA H1 approved, thus intended for food applications, wide service temperature range, hot and cold water resistant and also EPDM compatible Adhering lubricating grease for a wide temperature range; reduced adhesion and movement friction; good wear resistance; good corrosion protection effect Approved by USDA H1; adhering lubricating grease; particularly for applications with high switching frequencies and high air flow as well as at low temperatures For further information on recommended lubricants, please contact Klüber Lubrication München SE & Co. KG, www.klueber.com I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 577 X E D N I

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Seals for Fluid Power Applications – Pneumatics 5. INSTALLATION OF PNEUMATIC SEALS Before installation of sealing components, the complete system must be cleaned of machining residue, chips, dirt and other particles. Seals must not be pulled over sharp edges, threads, feather key grooves or similar during fitting. These areas must be covered before installation (→ Fig. 285). Sharp edges must be de-burred or cham- fered or smoothed off. Never use sharp- edged tools. The seal, piston rod and cylinder barrel must be oiled or greased before installa- tion. 5.1 INSERTION CHAMFERS ON RODS AND PIPES Cylinder bores and piston rods must be chamfered to prevent damage to the sealing components during installation. The length of the chamfer depends on the nominal diameter (→ Fig. 284). The dimensions are shown in → Tab. 32. The edge at the transition from chamfer to the sliding surface must be rounded and polished. LENGTH Z (CHAMFER) [mm] NOMINAL DIAMETER [mm] 2 3 4 5 6 7 8 < 20 0 … 49 50 … 99 100 … 159 160 … 249 250 … 400 > 400 Tab. 32 Values for lead-in Map-Marker-Exclamation Preventing damage during installation rounded, polished burr-free Z 20° burr-free 20° Z rounded, polished Fig. 284 Chamfering rods and tubes 578

579

F i g . 2 8 5 C o v e r i n g o f t h e t h r e a d s d u r i n g i n s t a l l a t i o n o f t h e s e a l 5 7 9 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS 5 . I n s t a l l a t i o n o f P n e u m a t i c S e a l s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

580

Seals for Fluid Power Applications – Pneumatics 5.2 INSTALLATION OF PNEUMATIC SEALS When installing individual sealing com- ponents, two types of fitting are possible (→ Fig. 286): y snap-in fitting in an undivided housing (installation recommendation I) y fitting in a divided housing (installation recommendation II) All edges around the seal housing must be carefully de-burred and rounded. The individual sealing components can generally be installed by hand without equipment (snap-in fitting → Fig. 287). Installation recommendation I (axially closed) Installation recommendation II (axially open) Fig. 286 Types of installation of rod seals 580

581

5. Installation of Pneumatic Seals Fig. 287 Snap-in fitting of a piston seal Fig. 288 Installation tool for rod seals Fig. 289 Installation tool for piston seals Left half: Start of installation Right half: Seal snapped in Installation can be simplified by using the appropriate installation tools (→ Fig. 288 and Fig. 289), which can be obtained from Freudenberg Xpress®. When using the two-component installation tool, the seal is pushed through the conical installation sleeve with the expanding mandrel and snaps into the groove (→ Fig. 290). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 290 Installation of rod seals 581 X E D N I

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Seals for Fluid Power Applications – Pneumatics If necessary, cover the first groove with the cover mounting sleeve Fig. 291 Installation aid for rod seals Another option is to use an installation aid (→ Fig. 291). The seal is initially posi- tioned by hand in the groove and then tightened with a mandrel (plastic or brass) until it snaps into the groove. If combination elements contain metal or plastic reinforcements, the groove must be designed to be axially accessible (→ Fig. 292). Installation is possible with- out special aids and can be automated for production lines. Mandrel Plug Fig. 292 Installation of multifunctional Fig. 293 Installation of pneumatic com- elements plete pistons 582

583

5. Installation of Pneumatic Seals Pneumatic complete pistons (TDUOP, Pneuko G, Pneuko M) are positioned on an offset piston rod and fastened with hexagon nuts (→ Fig. 293). Additional securing of the screw connection by using a self-locking nut or threadlocker is recom- mended. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O I T A C I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 583 X E D N I

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Seals for Fluid Power Applications – Pneumatics 584

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S T A T I C S E A L S 5 8 5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS S T A T I C S E A L S INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

586

Static Seals TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. GENERAL PRINCIPLES 3. INTRODUCTION 3.1 3.2 Static sealing Dynamic sealing 4. PRODUCT INFORMATION 5. FEATURE CLASSES 5.1 5.2 Dimensions and tolerances Limits of Imperfections 6. FUNCTION 7. INFLUENCING VARIABLES 8. DESIGN INFORMATION 8.1 General Surfaces Groove filling rate Stretching rate/Holding rate Compression rate 8.2 Guideline values for the design 9. MODIFICATIONS Surface treatment 9.1 9.2 Printing 9.3 Technical cleanliness 586 588 598 600 600 600 601 602 602 602 604 607 608 608 608 609 610 612 613 620 620 620 620

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10. INSTALLATION 10.1 Automatic installation 10.2 Expansion and compression 11. TECHNICAL SUPPORT 12. TESTS 13. CONFORMITIES 14. SPECIAL SEALS 14.1 Back-up ring SRA 14.2 Back-up ring SRI 14.3 Back-up ring SPR 14.4 Usit rings I, A, I SF 14.5 Hygienic Usit 14.6 Clamp seals for the process industry 14.7 Dairy coupling seals for the process industry 14.8 Customized flange seals for the process industry 14.9 Sealing Sheets/Edge Bonded Gaskets Table of Contents 622 622 622 623 626 627 628 628 629 630 631 635 637 639 640 642 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 587 X E D N I

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Static Seals 1. PRODUCT OVERVIEW 588 PRODUCT GROUPDESIGN DESCRIPTIONMAIN APPLICATIONSO-ringsO-ringClassic O-ring according to ISO 3601, axial and radial circular cross-sectionFor radial and axial sealing, suited for most statically sealed systemsMicro O-ringO-ring with axially and radi-ally circular cross-section; dimensionally below the scope of general dimensions of ISO 3601For radial and axial sealing in the smallest installation spacesX-ringCircular inner diameter, cross section in X-shapeFor radial and axial sealing mainly in highly dynamic systemsD-ringCircular inner diameter, cross section in D-shapeFor radial sealing of static systems or at low dynamic loads. Particularly well suit-ed for high pressures. Less susceptible to twistingR-ringCircular inner diameter, cross section in rectangular shapeFor radial sealing of static systems. Particularly well suited for high pressures and for sealing gasesOR-SFSpecial O-ring shapes. Axial and radial cross-sections by agreement within production- technical limitsDevelopment according to customer speciﬁcations speciﬁcally for the requested application

589

1. Product Overview Further information on our product portfolio I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 589 X E D N I MATERIALMAX. TEMPERATURE RANGE [°C] *STANDARD CATALOG RANGEFREUDENBERG XPRESS®VariousMaterial dependentYesYes70 FKM 576‒40 … +200NoNo75 FFKM 484‒10 … +230VariousMaterial dependentNoYesVariousMaterial dependentNoYesVariousMaterial dependentNoYesVariousMaterial dependentNoYes

590

DESIGN DESCRIPTION MAIN APPLICATIONS Bonded coatings Form closed dry film To improve handling and/or assembly; reduces wear; withstands high stretching Powder lubricant Layer not firmly adherent MoS 2, talc or graphite for improved handling Oil lubricant Layer not firmly adherent Fluorinated oil to improve assembly Surface treatment Applicable on any base material Chemical surface treatment for improved handling Static Seals PRODUCT GROUP Coating 590

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® — — — — Depending on the base material No Yes Depending on the base material No Yes Depending on the base material No Yes Depending on the base material No Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 591 X E D N I

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Static Seals PRODUCT GROUP Back-up rings DESIGN DESCRIPTION MAIN APPLICATIONS Back-up ring SRA Split back-up ring with a rectangular cross-section for externally-sealing O-rings Valves; cylinders Back-up ring SRI Split back-up ring with a rectangular cross-section for internally-sealing O-rings Valves; cylinders Back-up ring SPR Helic split bearing compo- nent with a rectangular cross-section Valves; cylinders Usit rings Usit I, A, I SF Metal flat seal with internal or external edge bonded, trapezoidal, rubber- elastic sealings (sealing washer). Design for internal or exter- nal sealing Bolted joints in general mechanical engineering Hygienic Usit Stainless steel washer with an external edge bonded, rubber-elastic sealing ge- ometries Hygienic sealing of screw connections in the food and pharmaceutical sectors 592

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® PTFE F52800; PTFE 177509 ‒70 … +260 (PTFE element) Yes Yes PTFE F52800; PTFE 177509 ‒70 … +260 (PTFE element) Yes Yes PTFE F52800; PTFE 177509 ‒70 … +260 (PTFE element) Yes Yes 70 NBR 177646 ‒30 … +100 75 FKM 177645 ‒30 … +200 70 EPDM 291 ‒40 … +150 70 EPDM 253815 ‒40 … +150 70 EPDM 217676 ‒40 … +150 75 Fluoroprene XP 45 ‒20 … +200 Yes No Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 593 X E D N I

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DESIGN DESCRIPTION MAIN APPLICATIONS Clamp seals Rotationally symmetrical sealing rings for static sealing of flanged joints according to DIN 32676 Flanges in the process industry Seals for dairy couplings Rotationally symmetrical sealing rings for static sealing of flanged couplings according to DIN 11851 Dairy couplings in the process industry Hygienic flange seals Static seal for customer- specific pipe connections and housings Pipe connections and hous- ings in the process industry Sealing sheets Sealing sheets/edge bonded gaskets connect several, often different sealing geometries. In principle, sealing sheets consist of a carrier part (e.g. a stamped metal sheet) with edge bonded sealing lips Hydraulic systems; engines and transmissions; auxiliary units Static Seals PRODUCT GROUP Flange seals Elastomer composite and precision molded parts 594

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A 70 EPDM 291 ‒40 … +150 70 EPDM 253815 ‒40 … +150 75 Fluoroprene XP 41 ‒15 … +200 70 VMQ 117055 ‒50 … +200 R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H Yes Yes R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P EPDM; ‒40 … +200 75 Fluoroprene XP 41; depending on the No Yes VMQ; HNBR material 70 EPDM 291 ‒40 … +150 75 Fluoroprene XP 41 ‒15 … +200 No Yes NBR; EPDM; FKM; HNBR ‒40 … +180 depending on the material No No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 595 X E D N I

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DESIGN DESCRIPTION MAIN APPLICATIONS Merkel® Cover seal PU82 One-piece, dual-action compact seal for static sealing – inner sealing Mobile cranes; construction machinery; industrial vehicles; forestry equipment; injection molding machines Merkel® Cover seal PU83 One-piece, dual-action com- pact seal for static sealing – external sealing Mobile cranes; construction machinery; industrial vehi- cles; forestry equipment; injection molding machines Merkel® Stircomatic SRC One-piece compact seal for static sealing – axial sealing Hydraulic hammers; hydraulic control devices Merkel® Pinmatic One-piece, dual-action compact seal for combined static and swivel sealing – internal sealing Knee levers; bearing and pivot bolts; injection mold- ing machines Static Seals PRODUCT GROUP Cover/knee lever seals 596

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® 95 AU V142 ‒30 … +110 Yes Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H 93 AU V167 ‒20 … +110 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 95 AU V142 ‒30 … +110 93 AU V167 ‒20 … +110 Yes Yes Yes Yes 95 AU V142 ‒30 … +110 No Yes R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 597 X E D N I

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Static Seals 2. GENERAL PRINCIPLES O-rings are among the simplest machine elements when it comes to producing a seal. However, anyone who has been in the situation of having to select an O-ring for their application will quickly realize that there is more to consider than first appears. The consequences of an incorrect design can directly lead to an assembly not being able to fulfill its function. Not in- frequently, this leads directly to danger to life and limb. It is no coincidence that the O-ring is often referred to as the C-part with an A-function. O-rings from Freudenberg Sealing Tech- nologies (hereinafter also abbreviated FST) are among the most popular sealing com- ponents in the world. Not least because FST offers consistency in terms of mate- rial attributes and compound formulas throughout the entire product lifecycle. Combined with years of expertise in all areas of mechanical engineering, this results in the benefits that make up the total FST package: y state-of-the-art materials expertise and variety y certified and approved material qualities y special coatings that reduce friction for installation-friendly processes y design variety, adapted to the customer’s specific application y low space requirement due to small installation spaces y easy installation and handling y optimal cost-benefit ratio FST Website O-rings Product catalog 598

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2. General Principles FST offers the ideal solution for virtually all applications, precisely matched in terms of material and design. O-rings are used in a wide variety of assemblies. Their functions range from splash protection and housing seals to safety-related com- ponents in automotive braking systems. The areas of application for Freudenberg O-rings cover a wide spectrum: y automotive industry y watch industry y energy technology y industrial engines y general mechanical and plant engi- neering y chemical industry y medical technology y agricultural and construction machinery y power tools and household appliances y commercial marine and offshore tech- nology y aviation y and more I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 599 X E D N I

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Due to its round cord cross-section, an O-ring in dynamic applications tends to twist, i.e. twist around the cord’s center of gravity. Under certain circumstances, this can lead to leakage, which often only occurs after a longer period of time. This can be remedied by using a more suitable design and/or an adapted cord cross-sec- tion (see also → Specially shaped O-rings, page 588). O-rings from Freudenberg Sealing Tech- nologies cover a comprehensive range of applications, but there are limits to what they can do. For very fast rotating or high- ly dynamic translatory applications, other sealing products from the Freudenberg product range may be better suited. If necessary, Freudenberg Sealing Technol- ogies sales staff will be happy to help you and present these sealing alternatives. Static Seals 3. INTRODUCTION An O-ring is a torus that is usually made of elastomer that separates two spaces and prevents a medium (gaseous or liquid) from passing from one space to the other. Depending on the application, a distinction is made between axial and radial seals. O-rings can be used to seal both static and moving machine parts. 3.1 STATIC SEALING When installed properly and designed correctly, static applications with pres- sures up to 1,000 bar can be sealed. The dimensions of the installation spaces depend on the cord thickness used and the respective applications. For pulsating pressures, a hardness of the O-ring mate- rial of ≥ 80 Shore A should be sought. 3.2 DYNAMIC SEALING The force resulting from the deformation leads to contact stress, which has a considerable influence on the wear be- havior of dynamic seals. Therefore, the sealing of dynamic systems, i.e. applica- tions in which the components to be sealed move relative to each other, is always a compromise between tightness and wear. The greater the deformation of the cord cross-section, the greater the resulting force and wear. If necessary, coatings can be used to counteract wear and ensure the longevity of the O-rings. Good lubrication, e.g. by the medium to be sealed or by oil nebulizers, reduces friction losses and wear. The compatibil- ity between the lubricant and the sealing material needs to be verified. 600

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4. PRODUCT INFORMATION 4. Product Information I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I According to ISO 3601, an O-ring is an endless ring that is round both in its cord cross-section and its top view. Deviating shapes are referred to as specially shaped O-rings (OR-SF), whereby the dimensional tolerances according to ISO 3601-1 and the grade characteristics according to ISO 3601-3 can be adopted for these special shapes. The ISO 3601-1 standard provides for only two dimensional sizes for an O-ring – the inner diameter (Ød1) and the axial cord thickness (Ød2). In practice, the introduc- tion of a third dimension has proven to be useful: the radial cord thickness (Ød3). With the introduction of this parameter, additional degrees of freedom are provid- ed for the design of the cord for special shapes, since, in contrast to the standard O-ring, the parameters Ød2 and Ød3 can be dimensioned differently. Depending on the cross-section, there are specific advantages that greatly expand the range of applications for Freudenberg sealing rings. Application-specific adap- tations of the cross-sectional shape are possible at any time in consultation with the experts at Freudenberg Sealing Tech- nologies. This means that a suitable seal can be developed for any sealing system. Examples include the reduction of the assembly force, permeation-optimized designs or rings with an anti-loss device for overhead installation. Miniaturization is advancing rapidly in all areas. Seals are also subject to this develop- ment. With the aid of special manufactur- ing technology, Freudenberg Sealing Tech- nologies is able to produce micro O-rings to the highest quality standards. R O F S L A E S Y R A T O R S N O T A C I I L P P A Ø d2 Ø d3 Ø d1 Fig. 294 O-ring in cross section with dimensions These ring dimensions are below the scope of general dimensions of ISO 3601, however Freudenberg Sealing Technologies follows this when defining the quality cri- teria. The lower limits for the ring dimen- sions are 0.75 mm for Ød1 and 0.4 mm for Ød2. In these cases, the dimensional tol- erances are highly dependent on the ma- terial and manufacturing process and must be agreed on a case-by-case basis. This means FST can provide the right seal- ing ring for every application. On request, sampling can be carried out in accordance with VD A or AIAG standards (IATF 16949) to confirm the consistently high quality of the components. Play-circle  Permeation and expl. decom- pression R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 295 Micro O-ring 601 X E D N I

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Static Seals 5. FEATURE CLASSES Freudenberg O-rings are usually manufac- tured in accordance with ISO 3601. The standard describes standards according to which a suitable O-ring can be devel- oped for each application in a material with appropriate properties and groove geometry. To support this, FST offers the O-Ring calculator. This helps users to quickly find an appropriate O-ring from the Freuden- berg portfolio. ISO recommendations, dimensions and information on the area of application are automatically taken into account. If no suitable ring is available as a standard product, a sales representative can be contacted directly from within the calcu- lator. If an O-ring is already available, the calculator can also be used to design the installation space. In the case of complex issues, a customer- specific solution can be developed in co- operation with the experts at FST. This includes deviations from the ISO standard dimensions and tolerances as well as de- viations from the classic circular O-ring cross-section. 5.1 DIMENSIONS AND TOLERANCES Part 1 of ISO 3601 deals with standardized ring dimensions and the related tolerances. The spectrum currently ranges from 0.74 mm to 658.88 mm for the inner diam- eter Ød1 and from 1.02 mm to 6.99 mm for the cord thickness Ød2. In addition, tolerance classes are defined in Part 1 depending on the dimensions: y tolerance class A: safety components, e.g. for brake sys- tems y tolerance class B: usually general industry applications The same tolerance classes can also be applied to O-rings that deviate from the ISO standard dimensions. 5.2 LIMITS OF IMPERFECTIONS ISO 3601-3 describes permissible form and surface deviations of O-rings. The deviations are defined as in → Tab. 33 and are divided into two classes: y grade N (normal quality) Quality limit AQL 1.0 or by agreement. These O-rings meet very high quality requirements and are suited for all common applications. It doesn’t matter whether the sealing is static or dynam- ic. Stock O-rings from Freudenberg Sealing Technologies are produced to normal quality y grade S (special quality) Quality limit AQL 0.65 or by agreement. These O-rings are only suited for ap- plications where the highest demands are placed on design and sealing capa- bility. Their production requires a con- siderably higher manufacturing and quality assurance effort than for normal quality O-rings. Special quality O-rings are not kept in stock and are only sup- plied on request depending on the dimensions and material needed. O-rings of normal and special quality differ in terms of the permissible feature sizes, irrespective of dimensional tolerances. O-Ring calculator 602

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5. Feature Classes A visual inspection of the various grade characteristics with characteristic sizes is carried out during production or quality control. Special arrangements are possible for special applications. TYPE OF DEVIATION SCHEMATIC DIAGRAM CRITERION ACC. TO ISO 3601-3 Offset and shape deviations Bead, flash, offset combined Notch e e e x y g u n Offset e flash height x flash width y Depth u Width g Deburring area Minimum dimension n Flow lines Recesses, indentations k t Depth k Length v Depth t Width w w v w Tab. 33 Shape and surface deviations according to ISO 3601-3 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 603 X E D N I

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Static Seals 6. FUNCTION The sealing effect of the O-ring is based on a deformation of its cross-section in the installed state, whereby the deforma- tion recommended by the ISO 3601-2 standard is based on the cord thickness used; the thinner the cord thickness, the greater the recommended deformation. For better comparability, the deformation is usually relative to the initial cross-section, which results in the percentage compres- sion of the ring. The reaction force generated by the com- pression of the ring results in the contact pressure required for sealing. It must be greater than the force generated by the media pressure applied. Depending on the configuration, the media pressure can be used as a supporting force by positioning the ring at the sealing gap and addition- ally compressing it, i.e. so-called pressure activation (→ Fig. 303, page 610). To correctly design an O-ring for a given groove, always take into account the possible extreme cases resulting from the manufacturing tolerances, i.e. the combination of the theoretically thickest possible OR cord with the smallest possible installation space and vice versa. When using O-rings as sealing elements, a distinction is made between installation with radial or axial deformation. While radial seals are used in both static and dynamic applications, axial seals are usu- ally used statically. Installation in a rectangular groove with radial deformation Classic applications for radial use include the sealing of shafts, where the groove can be made in the housing component (compressed installation) or in the shaft (expanded installation). Various aspects play a role in deciding which position is the right one, e.g. the cost of manufacturing the groove (→ Fig. 296). Installation in a rectangular groove with axial deformation Axial seals are mainly used as flange or cover seals (→ Fig. 297). For flange and cover seals, the cross-sec- tion of the O-ring is axially deformed. When determining the ring dimensions or the installation space, the pressure di- rection must be taken into account. Fig. 296 O-ring in a radial installation – left: Groove in a housing; right: Groove in a shaft 604

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6. Function In the case of external pressure, the inner diameter of the ring should correspond to the inner diameter of the groove or be slightly smaller. Similarly, ISO 3601 provides for slightly compressed mounting in the case of pressure from the inside. This type of de- sign is permissible. However, the central positioning of the ring offers the advan- tage of preventing the ring from jumping out of the groove due to compression. It may then be necessary to adjust the cord thickness, since the ring expands in the groove under the effect of pressure. Centered positioning also offers advan- tages if the components are to be assem- bled by automated systems. The damage caused by insufficiently positioned rings can be prevented. For cover seals in hydraulic cylinders, a design with radial sealing is preferable (→ Fig. 297 and Fig. 298) so that no gap enlargement occurs on the non-pressure side when the hydraulic tubes expand elastically under pressure load. Triangular groove Triangular grooves are sometimes used for bolted flanges and covers (→ Fig. 299). Freudenberg Sealing Technologies rec- ommends that triangular grooves not be used. The comparatively complex design results in minor deviations in large toler- ance fields. Designing such systems to be robust is therefore much more difficult than with a classic rectangular groove. If a rectangular groove cannot be used, the use of more appropriate sealing solutions, e.g. Usit rings, should be considered (→ “14.4 Usit rings I, A, I SF”, page 631). Trapezoidal groove Trapezoidal grooves are mainly used to ensure that the O-ring does not jump out of the groove during mounting (→ Fig. 300). This makes overhead installation much easier, for example, or prevents the O-ring from being squeezed during mounting in installation spaces that can- not be seen. Alternatively, dimple rings (→ Fig. 306, page 611) can be used, which can also be used to prevent loss in a classic rectangular groove. Fig. 297 O-ring in an axial installation Fig. 298 Radial arrangement for lid seals under high pressure I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 605 X E D N I

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Static Seals Fig. 299 O-ring in a triangular groove Fig. 300 O-ring in a trapezoidal groove The groove according to hygienic design rules is an absolute special case. Here, the theoretical principles of the DIN ISO 3601-2 standard are deliberately disre- garded in order to meet the special re- quirements of the food and beverage in- dustry, pharmaceuticals or medical technology, see also the EHEDG guidelines or corresponding standards (e.g. DIN 11864). The complex structure of the groove requires detailed consideration of the theoretically possible extreme situations, e.g. to avoid groove overfilling and the associated loss of function. Removal of an O-ring from a trapezoidal groove is generally not possible without using the right tools. Special grooves In addition to the grooves described above, other shapes are used in rare cases. These are usually due to higher-order reasons, e.g. the manufacturing process of the housing parts and/or application cases. The most common shapes are: y half trapezoidal groove y two-piece rectangular groove 606

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7. INFLUENCING VARIABLES 7. Influencing Variables Dynamic systems are always subject to the compromise between wear and seal- ing effect. However, with FST’s expertise, a suitable ring can be defined for every application. To ensure that all the necessary informa- tion is available, ask your contact person for the EIS sheets (Engineering Information Sheets). All relevant parameters are ad- dressed here. The boundary conditions that must be known, at minimum, in order to correct- ly design an O-ring are the medium to be sealed, the groove geometry and surface, and the temperature and pressure pro- files. For dynamic applications, relative speeds and/or frequencies are also required. The first decisions are derived from this and form the basis for the later make-up of the sealing system. O-rings from Freudenberg Sealing Tech- nologies can be used in both static and dynamic applications. In individual cases, special shapes are used, which can be developed in close cooperation with the experts at FST. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 607 X E D N I

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Static Seals 8. DESIGN INFORMATION 8.1 GENERAL SURFACES Locating grooves for O-rings are generally rectangular. Dimensional guide values can be found at the end of this section and in ISO 3601-2 (→ “8.2 Guideline values for design,” page 613). If necessary for pro- duction reasons, the flanks can be in- clined by up to 5°. In the case of pulsating pressures, the roughness depth must be refined. The recommendations regarding surface quality are listed in → Tab. 35. Map-Marker-Exclamation Lead in chamfer for safe, damage-free installation max. 5° r1 b r2 b [mm] r1 [µm] ≤ 3 > 3 0.1 0.2 r2 [µm] 0.25 0.50 Tab. 34 Recommendations for the edge radii of the groove The radii r1 and r2 are designed depending on the groove width b (→ Tab. 34). In- stead of the rounding r2 at the base of the groove, a chamfer of the same size at an angle of 45° can be selected. The machine parts that come into contact with the O-ring must be carefully deburred. All foreign bodies must be removed before mounting. Steel is most often used for rods and tubes. Cleanly smoothed and non-porous cast iron is also suitable. Aluminum, bronze or brass can show increased wear under dynamic stress due to comparatively low hardness. However, they are used for cer- tain applications. To ensure that the O-ring can be pressed into the groove without being damaged, the rod or housing is chamfered. The angle of the lead in chamfer should be in the range of 15° to 20°. In addition, a sufficient length of the lead in chamfer Z must be se- lected so that the O-ring is only deformed SURFACE APPLICATION MEDIA PRINTING Ra [μm] Rz [μm] Groove base and flanks Static axial Constant Static radial Constant Pulsating Dynamic Sealing surface Static Constant Pulsating Dynamic 3.2 1.6 1.6 0.8 1.6 0.8 0.4 Tab. 35 Recommendations for the surface roughness of the sealing partners 12.5 6.3 6.3 3.2 6.3 3.2 1.6 608

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8. Design Information 15° 15° Fig. 301 Recommendations for the lead in chamfer I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P over the chamfer, even with poor tolerance combinations. The transitions must be carefully rounded. If the installation space has no or no suitable lead in chamfer or the O-ring comes into contact with the front edge, the O-rings can be damaged during mounting and thus become leakproof. If necessary, the use of an assembly aid should be checked. GROOVE FILLING RATE The volume of the installation groove must always be greater than the volume of the O-ring. The ratio between the volume of the largest ring and the smallest possible installation groove should not exceed 0.9 (groove filling level). This requirement This requirement is based on the significantly higher volume increase of elastomer under the influence of temperature compared to steel and/or aluminium. Furthermore, an increase in volume due to chemical in- fluence is also possible (swelling). For installation reasons, an expanded design with pressure from the inside is perfectly permissible, but must be checked/considered for its effect on the compression. The media pressure increases the contact stress acting between the O-ring surface and the groove or sealing surface. At high media pressures, the gap width between the sealing partners must be adjusted accordingly. High pressures can cause the O-ring to be pressed into the gap and ex- trude. The permissible gap width depends on the media pressure, the pressure profile, the Shore hardness of the elastomer and whether the seal is static or dynamic. If the gap cannot be made small enough for certain reasons, it is possible to prevent any gap extrusion that can occur by using a back-up ring (→ “14. Back-up rings,” page 628). Map-Marker-Exclamation Groove filling level ≤ 90% S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 302 Groove filling left: OK; right: groove overfilled 609 X E D N I

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Static Seals Fig. 303 Left: installed ring; center: pressure-activated ring; right: gap extrusion Back-up ring necessary O O R 7 2 S h ore A R 9 0 S h o r e A 0.30 0.25 0.20 0.15 0.10 0.05 ] m m [ h t i d w p a G Back-up ring necessary O O R 7 2 S h ore A R 9 0 S h o r e A 0.30 0.25 0.20 0.15 0.10 0.05 ] m m [ h t i d w p a G 63 100 160 210 250 13 30 63 100 Media pressure [bar] Media pressure [bar] Fig. 304 Gap extrusion at different elastomer hardnesses; left: static seal; right: dynamic seal STRETCHING RATE/HOLDING RATE Rings that are inserted into the groove of a piston should be installed with rela- tively high stretch. This has proven to be successful in practice, as it reduces the possibility of damage to the O-ring dur- ing mounting. The maximum stretch in the installed condition should not be greater than 15% (smallest ring inside diameter/largest groove base diameter). Due to the incompressibility of the elasto- mer, the expansion leads to the tapering of the cord thickness, which must be tak- en into account in the design. The O-ring must be sufficiently dimen- sionally stable for use as a rod seal, other- wise it will fall out of the groove under its own weight during vertical installation. The maximum compression (max. outer diameter and min. groove base diameter) should be approx. 3%. Care should be taken to ensure that the ring does not protrude too far from the groove when the rod is mounted so that it is not damaged during installation. Map-Marker-Exclamation Maximum stretch not > 15%, maximum compression approx. 3% 610

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8. Design Information d2/d1 0.01 0.05 0.10 0.50 1.00 1.50 ] % [ n o i t c u d e r n o i t c e s - s s o r C 12 10 8 6 4 2 0 0 5 10 15 20 Stretch [%] Fig. 305 Reduction in the cross-section of an O-ring as a function of stretching and ratio d2/d1 In determining the compression, it is rec- ommended that the outer diameter tol- erance of the ring not be calculated using the tolerances of the ring inner diameter plus twice the tolerances of the radial cord thickness. Rather, the outer diameter tolerance of the ring should be deter- mined by the adequate tolerance of the corresponding inner diameter (the outer diameter has the tolerance of the compa- rable inner diameter). If axial seals are to be secured against loss, FST advises against positioning the ring by compression. Technically this is possible, but due to the stresses, there is a possi- bility that the ring will jump out of the groove. This can cause the ring to be crushed during installation or even to fall completely out of the installation space. If it is to be ensured that the ring remains in the groove, during overhead assembly or transport of the ring for example, nob rings are often used. Fig. 306 Nob ring The nobs distributed around the circum- ference compress the ring radially and thus hold the ring in the groove. The experts at Freudenberg Sealing Technologies will be happy to assist you in designing such a ring. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 611 X E D N I

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Static Seals Map-Marker-Exclamation Tolerance of installation space and O-ring 612 COMPRESSION RATE The compression of the ring is elementary for the sealing function. In principle, very slight compression is sufficient for the O-ring to fulfill its sealing function. How- ever, it must also be borne in mind that the different thermal expansions of elas- tomer and steel have an influence on the actual compression. Compression de- creases with falling temperatures, while it increases with rising temperature. Freudenberg Sealing Technologies rec- ommends the compression ratios speci- fied in ISO 3601-2 for static and dynamic applications. Due to the dimensional tolerances to which the O-ring and the installation space are subject, there is a certain compression range. For smaller ring dimensions, nominally equal tolerances have a greater effect. For this reason, the recommended compression for small O-rings provides for a wider compression range. In some applications, it makes sense to use a special O-ring form (OR-SF) instead of an O-ring due to the load, which deviates in cross-section from the classic O-ring forms. FEM simulations can be performed in case of more complex challenges. Here, for example, compression, deformation and contact stresses can be calculated to ensure that the sealing ring optimally meets the requirements. The data shown in the following tables can be used as guide values for the design of the groove. Even if these are used, Freudenberg Sealing Technologies rec- ommends that a tolerance analysis of the installation space and O-ring be carried out to ensure that neither leakage nor damage to the O-ring can occur. Fig. 307 Compressed ring in an FEM simulation

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8.2 GUIDELINE VALUES FOR THE DESIGN 8. Design Information AXIAL-STATIC Ø d7 H9 Ø d8 h9 b h r Fig. 308 Static axial sealing design CORD THICKNESS D2 [mm] GROOVE DEPTH h (0/0.1) [mm] GROOVE WIDTH b (0/0.2) [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.0 1.1 1.2 1.4 1.7 1.8 1.9 2.2 2.7 3.1 3.5 3.9 4.2 4.5 4.6 4.8 5.3 5.8 6.2 6.8 6.9 7.4 7.8 8.3 9.3 10.2 10.8 11.6 2.4 2.5 2.7 2.9 3.4 3.5 3.6 4.1 4.6 5.1 5.4 6.3 6.6 6.6 6.9 7.3 7.8 8.2 8.8 9.2 9.8 10.6 11.1 11.6 12.6 13.6 15.0 16.2 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Tab. 36 Guideline values for dimensioning – axial-static 613 X E D N I

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Static Seals RADIAL-STATIC PISTON SEAL Z 15° t Ø d3 h6 Ø d4 H8 r b Ø d9 f7 Fig. 309 Static radial sealing piston seal CORD THICKNESS d2 [mm] SEAL SURFACE DISTANCE t [mm] GROOVE WIDTH b + 0.25 [mm] LEAD IN CHAMFER Z [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.10 1.15 1.30 1.50 1.80 1.90 2.00 2.30 2.70 3.10 3.50 3.90 4.20 4.40 4.50 4.80 5.20 5.60 6.00 6.40 6.70 7.20 7.60 8.00 8.70 9.60 10.40 11.20 2.0 2.2 2.3 2.5 3.0 3.1 3.2 3.7 4.2 4.7 5.2 5.9 6.2 6.3 6.6 6.9 7.4 7.9 8.5 9.2 9.7 10.4 11.0 11.6 13.0 14.0 15.3 16.4 1.5 1.6 1.7 1.7 2.0 2.0 2.1 2.3 2.7 2.8 3.1 3.4 3.4 3.4 3.6 3.6 3.9 4.1 4.4 4.6 4.9 5.3 5.5 5.8 6.9 7.0 7.6 8.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 Tab. 37 Guideline values for dimensioning – radial-static piston seal 614

615

8. Design Information RADIAL-STATIC ROD SEAL b r 15° Z Ø d10 H8 Ø d5 f7 t Ø d6 H9 Fig. 310 Static radial sealing rod seal CORD THICKNESS d2 [mm] SEAL SURFACE DISTANCE t [mm] GROOVE WIDTH b + 0.25 [mm] LEAD IN CHAMFER Z [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.18 1.27 1.42 1.61 1.94 2.04 2.15 2.48 2.91 3.31 3.72 4.12 4.42 4.57 4.73 4.88 5.38 5.92 6.34 6.75 7.06 7.54 7.91 8.30 9.02 9.67 10.24 10.74 2.10 2.20 2.40 2.60 3.10 3.20 3.30 3.80 4.40 4.90 5.50 6.10 6.40 6.60 6.90 7.30 7.80 8.20 8.80 9.30 9.90 10.50 11.20 11.80 12.90 14.20 15.50 16.80 1.70 1.74 1.84 2.00 2.32 2.34 2.36 2.60 3.00 3.34 3.80 4.20 4.34 4.44 4.60 5.16 5.24 5.10 5.50 5.86 6.40 6.90 7.40 8.10 9.20 10.64 12.30 14.26 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Tab. 38 Guideline values for dimensioning – radial-static rod seal 615 X E D N I

616

Static Seals RADIAL-DYNAMIC HYDRAULIC PISTON SEAL Z 15° t Ø d3 h6 Ø d4 H8 r b Ø d9 f7 Fig. 311 Dynamic radial sealing hydraulic piston seal CORD THICKNESS d2 [mm] SEAL SURFACE DISTANCE t [mm] GROOVE WIDTH b + 0.25 [mm] LEAD IN CHAMFER Z [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.10 1.15 1.30 1.50 1.80 1.90 2.00 2.30 2.70 3.10 3.50 3.90 4.20 4.40 4.50 4.80 5.20 5.60 6.00 6.40 6.70 7.20 7.60 8.00 8.70 9.60 10.40 11.20 2.0 2.2 2.3 2.5 3.0 3.1 3.2 3.7 4.2 4.7 5.2 5.9 6.2 6.3 6.6 6.9 7.4 7.9 8.5 9.2 9.7 10.4 11.0 11.6 13.0 14.0 15.3 16.4 1.5 1.6 1.7 1.7 2.0 2.0 2.1 2.3 2.7 2.8 3.1 3.4 3.4 3.4 3.6 3.6 3.9 4.1 4.4 4.6 4.9 5.3 5.5 5.8 6.9 7.0 7.6 8.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 Tab. 39 Guideline value for dimensioning – radial-dynamic hydraulic piston seal 616

617

8. Design Information RADIAL-DYNAMIC HYDRAULIC ROD SEAL b r 15° Z Ø d10 H8 Ø d5 f7 t Ø d6 H9 Fig. 312 Dynamic radial sealing hydraulic rod seal CORD THICKNESS d2 [mm] SEAL SURFACE DISTANCE t [mm] GROOVE WIDTH b + 0.25 [mm] LEAD IN CHAMFER Z [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.18 1.27 1.42 1.61 1.94 2.04 2.15 2.48 2.91 3.31 3.72 4.12 4.42 4.57 4.73 4.88 5.38 5.92 6.34 6.75 7.06 7.54 7.91 8.30 9.02 9.67 10.24 10.74 2.10 2.20 2.40 2.60 3.10 3.20 3.30 3.80 4.40 4.90 5.50 6.10 6.40 6.60 6.90 7.30 7.80 8.20 8.80 9.30 9.90 10.50 11.20 11.80 12.90 14.20 15.50 16.80 1.70 1.74 1.84 2.00 2.32 2.34 2.36 2.60 3.00 3.34 3.80 4.20 4.34 4.44 4.60 5.16 5.24 5.10 5.50 5.86 6.40 6.90 7.40 8.10 9.20 10.64 12.30 14.26 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Tab. 40 Guideline value for dimensioning – radial-dynamic hydraulic rod seal 617 X E D N I

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Static Seals RADIAL-DYNAMIC PNEUMATIC PISTON SEAL Z 15° t Ø d3 h6 Ø d4 H8 r b Ø d9 f7 Fig. 313 Dynamic radial sealing pneumatic piston seal CORD THICKNESS d2 [mm] SEAL SURFACE DISTANCE t [mm] GROOVE WIDTH b + 0.25 [mm] LEAD IN CHAMFER Z [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.15 1.20 1.35 1.55 1.90 2.00 2.10 2.40 2.80 3.30 3.70 4.10 4.40 4.50 4.70 4.90 5.40 5.80 6.10 6.60 7.00 7.40 7.80 8.30 9.10 9.90 10.80 11.60 1.9 2.1 2.2 2.4 2.7 2.8 2.9 3.4 3.8 4.2 4.8 5.4 5.7 6.0 6.1 6.5 7.0 7.5 8.2 8.7 9.0 9.9 10.5 10.9 12.1 13.2 14.3 15.4 1.3 1.5 1.5 1.6 1.7 1.7 1.8 1.9 2.0 2.1 2.3 2.7 2.8 2.9 3.0 3.2 3.3 3.4 4.0 4.1 4.2 4.6 4.8 4.9 5.3 5.9 6.1 6.6 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 Tab. 41 Guideline value for dimensioning – radial-dynamic pneumatic rod seal 618

619

8. Design Information RADIAL-DYNAMIC PNEUMATIC ROD SEAL b r 15° Z Ø d10 H8 Ø d5 f7 t Ø d6 H9 Fig. 314 Dynamic radial sealing pneumatic rod seal CORD THICKNESS d2 [mm] SEAL SURFACE DISTANCE t [mm] GROOVE WIDTH b + 0.25 [mm] LEAD IN CHAMFER Z [mm] GROOVE RADIUS r [mm] 1.50 1.60 1.78 2.00 2.40 2.50 2.62 3.00 3.53 4.00 4.50 5.00 5.33 5.50 5.70 6.00 6.50 6.99 7.50 8.00 8.40 9.00 9.50 10.00 11.00 12.00 13.00 14.00 1.24 1.30 1.46 1.65 2.00 2.09 2.25 2.59 3.10 3.53 3.95 4.40 4.69 4.84 5.02 5.28 5.70 6.22 6.66 7.10 7.40 7.91 8.33 8.68 9.48 10.18 10.85 11.41 2.00 2.15 2.30 2.50 3.00 3.05 3.10 3.60 4.10 4.60 5.20 5.70 6.10 6.30 6.50 6.80 7.40 7.90 8.40 8.90 9.50 10.10 10.70 11.40 12.50 13.80 15.00 16.30 1.45 1.50 1.60 1.70 1.95 2.00 2.00 2.00 2.20 2.40 2.80 3.10 3.20 3.30 3.40 3.60 4.00 3.90 4.20 4.40 5.00 5.40 5.70 6.60 7.40 8.70 10.00 11.70 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.3 ±0.1 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 0.6 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.0 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.4 ±0.2 1.6 ±0.2 1.6 ±0.2 1.6 ±0.2 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Tab. 42 Guideline value for dimensioning – radial-dynamic pneumatic rod seal 619 X E D N I

620

Static Seals 9. MODIFICATIONS The Freudenberg portfolio includes dif- ferent coating systems. These can be: y surface treatment y powder lubricants y bonded coatings y oil lubricants y color coating In consultation with its experts, FST is able to select the right surface treatment for each application. 9.2 PRINTING Freudenberg Sealing Technologies can apply visual distinguishing features to O-rings using a special printing process on the ring surface (→ Fig. 315). The print samples are characterized by a high degree of customizability. In addition to standard patterns, customer-specific print patterns and lettering can also be realized after prior consultation (see also → chapter “Services – Product Marking”, page 15). 9.3 TECHNICAL CLEANLINESS For applications with high cleanliness requirements, O-rings can be ordered as Clean & Pack articles. Here, the sealing elements undergo an additional process step. In the clean room, the O-rings are washed again and packaged directly. They are then analyzed for foreign particles in accordance with ISO 16232/VDA19. Fig. 315 Examples of printed rings As an option, O-rings from Freudenberg Sealing Technologies can be modified to meet special customer-specific require- ments in the following areas: y feeding and separation y installation aids y wear resistance y friction reduction y differentiation and verification y cleanliness 9.1 SURFACE TREATMENT Coatings are mainly used when special requirements are placed on the sepa- ration of rings or assembly forces (→ chapter “Services – Coating”, page 11). It goes without saying that Freudenberg coatings are predominantly VOC-free and comply with the currently applicable legal requirements with regard to REACH and RoHS. The coating portfolio is char- acterized by a high degree of diversity. This enables the use of O-rings in a wide range of different applications. This includes nearly all areas that can be re- levant in mechanical and plant engineering. Play-circle  Coating Overview treatment possibilities 620

621

9. Modifications In the following → Tab. 43, you will find further details on the limit values that can be assigned by the Clean & Pack pro- cess. The properties of the ring are not negatively influenced by this process in any way. TECHNICAL CLEANLINESS ACCORDING TO CLEAN & PACK Maximum particle size Maximum particle size (metallic particles) Maximum fiber length 600 μm 300 μm 2,000 μm Particle size distribution CCC = A (C14/D13/E12/F9/G7/H5/I3/J-K00) Maximum gravimetric content of particles 3 mg/1,000 cm2 Tab. 43 Assured cleanliness level according to Clean & Pack l s e c i t r a p f o r e b m u N 10,000 1,000 100 10 1 0.1 Standard processes Clean & Pack Standard Prozesse 100–150 150–200 200–400 400–600 600–1,000 > 1,000 Size classes of particles [µm] I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 316 Reduction of particles through the Clean & Pack process 621 X E D N I

622

10.2 EXPANSION AND COMPRESSION O-rings from Freudenberg Sealing Tech- nologies can be subjected to a permanent expansion of 5 to 15% without any prob- lems. Many practical applications have shown that a higher expansion rate has a positive effect on the installation process. This reduces the risk of twisting and shearing, especially in the case of long in- stallation distances. The compression of the O-ring in axial installation should not exceed 3%, other- wise there is a risk of ring distortion and shearing during assembly. In case of doubt, central positioning should be chosen. The values listed for expansion and com- pression are ideal values that cannot always be maintained in practice. Par- ticularly in the case of larger expansions, the installation space of the O-ring must be corrected accordingly in order to ensure sufficient compression and stretching. Static Seals 10. INSTALLATION Before installing O-rings, the entire system should be cleaned to remove dirt and ma- chining residues. O-rings should not be pulled over sharp edges, offset shafts, threads, grooves or similar. It is advisable to cover sharp edges during installation to prevent damage. The O-ring must not be twisted in the locating groove. Brief stretching during in- stallation is permissible. However, it should be noted that the O-ring requires some time to return to its original shape due to its material properties. When installing it as a piston or shaft seal with an outside diameter of less than 10 mm, special care must be taken because of the large percent- age expansion. The use of a mounting man- drel or a mounting sleeve is recommended (see also → chapter “Services – Installation and Deinstallation aids”, page 14). 10.1 AUTOMATIC INSTALLATION For automatic part handling of O-rings, it is very important to keep the form and position deviations of the seals within de- fined limits before feeding them into the machine. The limit values here depend on the actual installation process and the ring dimensions. Generally accepted recom- mendations based on the experience values of manufacturers of machines for automated installation are generally complied with by Freudenberg O-rings. With its coating systems, FST can also provide additional support for ensuring a smooth automatic installation process. For example, installation forces can be reduced or the individualization of the O-rings facilitated (→ “9.1 Surface treat- ment,” page 620). Map-marker-edit Damage due to sharp edges 622

623

11. TECHNICAL SUPPORT 11. Technical Support cause of the damage (→ chapter “Services – Damage Analysis”, page 16). Among other methods, these include: y REM/EDX y light microscopes y AF M and WLI y CT and nanoCT y spectroscopic methods Damage to the O-ring that occurs during use and can lead to leakage can in most cases be traced back to the specific cause on the basis of the damage pattern. The most common damage patterns can be seen in the following table. This again shows how important the right choice of the material and the correct design of the groove and O-ring are for the reliability of the sealing system. Freudenberg Sealing Technologies sees itself as a strong development partner throughout the entire lifecycle of an O-ring. The experts in the O-ring division are al- ways available to help you develop the right O-ring design for your installation space. With years of expertise in all areas of mechanical engineering, coupled with a wide range of materials, FST can develop the right solution for all situations. The Freudenberg Group has an accredit- ed laboratory where all relevant tests can be carried out. Here, necessary tests can be carried out at short notice as part of O-ring design development if not all rel- evant characteristic values are available (→ chapter “Services – Test Benches”, page 17). For example, the following tests are possible: y compatibility tests of the O-ring ma- terial with the medium to be sealed y determination of thermal parameters y determination of mechanical param- eters (static and dynamic) y tribological investigations y investigation of the permeation behavior y chemical analytics Furthermore, various CAE tools are avail- able. For example, the behavior of the O-ring during installation and in the in- stalled state can be simulated under me- dia pressure in order to identify potential risks of damage to the ring in good time and to take countermeasures. In addition, the resulting contact stresses can be de- termined, which are ultimately responsible for the sealing effect. In addition, all methods are available to analyze damage cases from pre-series tests or from the field and to determine the I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 623 X E D N I

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Static Seals DAMAGE PATTERN POSSIBLE CAUSES Abrasion Permanent deformation Insufficient lubrication by the system fluid, mixed friction or poor venting Surfaces too smooth or too rough Contaminated system fluid Incorrect choice of material Temperature too high Swelling due to medium Incorrect dimensioning Groove filling level Incorrect choice of material Explosive decompression Rapid pressure change in gas application Incorrect choice of material Mechanical damage Swelling Gap extrusion 624 Incorrectly selected O-ring geometry Elastomer too soft Defective lead in chamfer Mechanical damage Unknown components in the feed medium (additives) Incorrect choice of material Impermissible gap widths/eccentric mounting position System pressure too high Component deformation Incorrect choice of material Crowded or sharp-edged groove

625

11. Technical Support I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A DAMAGE PATTERN POSSIBLE CAUSES Thermal overload Twisting Overpressing Local temperatures too high Stagnation of the medium at the sealing point Insufficient heat dissipation Low expansion Long insertion paths Unsuitable ring design Slow linear velocity Groove width too large Ring compressed too much Incorrect design Thermal expansion/swelling not considered Chemical attack Incompatibility with the medium used R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 625 X E D N I

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Static Seals 12. TESTS The usual tests carried out as part of the quality control of elastomer components are naturally also applied to Freudenberg O-rings (→ chapter “Services – Test Benches”, page 17). The following in particular should be mentioned here: y compression set (DVR) y hardness [IRHD] y dimensions y visual surface inspection In addition, other tests are possible if you contact us. More also in the → chapter “Services – Laboratory Tests”, page 18 and → chapter “Materials and process en- gineering – 8. Testing methods”, page 143. Freudenberg Sealing Technologies has the technical capability to subject certain in- spection characteristics to an automated 100% check. These include dimensional inspections of the inner diameter (Ød1) and the radial cord thickness (Ød3). These are carried out without contact using calibrated camera systems. At the same time, the surface of the rings is inspected on both sides for irregulari- ties. Any deviations from the standard or specification are thus automatically detected and rejected. 626

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13. CONFORMITIES 13. Conformities For a large number of applications, it is assumed that certain specifications are met. These can be based on custom- er-specific or statutory regulations. Freudenberg O-rings and the materials and coatings used to manufacture them are checked for conformity regularly or, in some cases, even specially developed to meet them. y automotive OEMs and their suppliers • Refrigerants: permeation and explosive • Hydrogen periphery of fuel cells: free of cell toxins • E-Mobility battery cell seals and EMI shielding according to specific market requirements • Wide range of current OEM and an- imal material approvals y aerospace OEMs • Operating temperature (e.g. low- temperature applications) • Resistance to aggressive media (e.g. Skydrol) decompression (e.g. DIN SPEC 74102) y approvals for oil and gas applications • Various approvals for safety-relevant components in hydraulic and pneu- matic braking systems • Optimized materials with regard to friction and wear • Material compatibility in accord- ance with applicable international and customer-specific standards • High- and low-temperature behavior • Resistance to aggressive media, e.g. in systems carrying coolant, fuel, ex- haust gas or oil (e.g. OAT, NOAT) • Material specifications regarding fire protection, e.g. UL 94 V-0 (e.g. Norsok M710) y food (conformities for e.g. F D A, USP Class VI, 3-A® Sanitary Standard Class II, Reg. (EC) 1935/2004 and 2023/2006 (GMP), NSF Arrete51) y ADI-free y RoHS y in addition, Freudenberg Sealing Tech- nologies naturally complies with the specifications described in the general section I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 627 X E D N I

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Static Seals 14. SPECIAL SEALS 14.1 BACK-UP RING SRA PRODUCT BENEFITS y Expanded application range for O-rings y High material and product quality y Wide selection of standard dimen- sions INSTALLATION AND ASSEMBLY The surface finish requirements corre- spond to the values listed. Gap width: when using PTFE back-up rings, operating pressures of < 40 MPa (400 bar) or gap widths up to 0.3 mm can be bridged. PRODUCT DESCRIPTION Slit bearing component with a rectangular cross-section for ISC O-rings sealing on the outside. USES Back-up rings are not sealing elements, but only have a protective and supporting function for radially sealing O-rings. Under pressure, the back-up ring deforms and thus prevents gap extrusion of the rela- tively soft O-ring in dynamic use. MATERIAL MATERIAL Unfilled PTFE CODE PTFE F52800 or PTFE 177509 OPERATING CONDITIONS MATERIAL TEMPERATURE RANGE [°C] AREAS OF APPLICATION PTFE F52800 or PTFE 177509 ‒70 … +260 * (valid only for PTFE element) All fluids used in hydraulics * depending on the O-ring material used 628

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14. Special Seals 14.2 BACK-UP RING SRI PRODUCT BENEFITS y Expanded application range for O-rings y High material and product quality y Wide selection of standard dimen- sions INSTALLATION AND ASSEMBLY The surface finish requirements corre- spond to the values stipulated. Gap width: When using PTFE back-up rings, operating pressures of < 40 MPa (400 bar) or gap widths up to 0.3 mm can be bridged. PRODUCT DESCRIPTION Slit bearing component with a rectangu- lar cross-section for ISC O-rings sealing on the inside. USES Back-up rings are not sealing elements, but only have a protective and support- ing function for radially sealing O-rings. Under pressure, the support ring deforms and thus prevents gap extrusion of the relatively soft O-ring in dynamic use. MATERIAL MATERIAL Unfilled PTFE CODE PTFE F52800 resp. 177509 OPERATING CONDITIONS I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B MATERIAL TEMPERATURE RANGE [°C] AREAS OF APPLICATION PTFE F52800 or PTFE 177509 ‒70 … +260 * (valid only for PTFE element) All fluids used in hydraulics * according to the O-ring material used S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 629 X E D N I

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Static Seals 14.3 BACK-UP RING SPR PRODUCT BENEFITS Advantage compared to conventional back-up rings: y Even in cases where considerable temperature fluctuations occur, i.e. if there is post-shrinkage of the back-up ring, at least one turn of the spiral will be left to support the ISC O-ring over the gap at any point around the circumference y Also suitable for non-standard di- ameters, as the ring can be short- ened and thus adapted to fit. Gap width: When using spiral back- rings made of PTFE, operating pressures of ≤ 40 MPa (400 bar) or gap widths up to 0.3 mm can be bridged. Special sizes or special materials are avail- able on request. PRODUCT DESCRIPTION Helical split bearing component with a rectangular cross-section. USES Back-up rings are not sealing elements, but only have a protective and support- ing function for radially sealing O-rings. Under pressure, the support ring deforms and thus prevents gap extrusion of the relatively soft O-ring in dynamic use. INSTALLATION AND ASSEMBLY The surface requirements correspond to the specified values. MATERIAL APPLICATION MATERIAL Unfilled PTFE CODE PTFE F52800 or PTFE 177509 MATERIAL TEMPERATURE RANGE [°C] AREAS OF APPLICATION PTFE F52800 or PTFE 177509 ‒70 … +260 * (valid only for PTFE element) All fluids used in hydraulics * depending on the O-ring material used 630

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14. Special Seals 14.4 USIT RINGS I, A, I SF PRODUCT BENEFITS y Easy installation y Frictional connection y Secure, self-reinforcing seal y Suited for use with high pressures DESIGNS y internally sealing design I (for internal pressure) y internally sealing design with centering I SF (for internal pressure with a cen- tering aid) y externally sealing design A (for external pressure) Fig. 317 Usit ring I PRODUCT DESCRIPTION Metallic flat seal with inner or outer edge bonded trapezoidal, rubber-elastic seal- ing bead (sealing washer). The non-stainless-steel variants are pro- vided with a CR VI free electrogalvanic coat- ing for corrosion protection (comparable to Galvanic Coating Iso 2081 Fe/Zn5/C (Cr VI free)). USES Static sealing of y screw fittings y flange connections in mechanical and plant engineering. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 318 Usit ring A Fig. 319 Usit ring I SF 631 X E D N I

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Static Seals MATERIAL COMPONENTS Metal ring Sealing bead Surface protection metal ring AREAS OF APPLICATION DESCRIPTION Steel SPCC (similar to DC01 290) High-strength steel SPCC-1B (similar to DC01 C590) Stainless steel SUS 304 (similar to X5CrNi 18-10) 70 NBR 177646 75 FKM 177645 Other materials available on request as special production SPCC: electrogalvanic coating (comparable to Galvanic Coating Iso 2081 Fe/Zn5/C (Cr VI free)) SPCC-1B: electrogalvanic coating (comparable to Galvanic Coating Iso 2081 Fe/Zn5/C (Cr VI free)) SUS304: none MATERIAL TEMPERATURE RANGE [°C] AREAS OF APPLICATION NBR FKM ‒30 … +100 Max. +200 Max. +150 Mineral oils (according to DIN 51524); pressure fluids HFA, HFB, HFC (according to VDMA 24320) Hot air Mineral oils (according to DIN 51524); Pressure fluids (according to VDMA 24320) OPERATING PRESSURE Attention! The pressures specified here only apply if the Usit ring is pressurized from the elastomer side. If the pressure comes from the metal side (not recommended), the max. operating pressure is 1.2 MPa. Maximum operating pressure: y < 100 MPa (installation in countersink) y < 40 MPa (installation without coun- tersink for Ø < 40 mm; only for USF) y < 25 MPa (installation without coun- tersink at Ø > 40 mm) 632

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14. Special Seals In the case of Usit rings with external sealing, the outer diameter (ØDM) should be selected so that it lies flat under the bolt head (taking into account the toler- ances and eccentricity). It should be noted that the outer diameter of the Usit ring (ØDM) increases by approx. 0.6 during in- stallation. R max 0.2 b1 b1 S Ø DM Ø D1 Ø dM Fig. 321 Usit ring A Tightening torque CARRIER MATERIAL MAX. TORQUE TIGHTENING SPCC SPCC-1B/SUS304 Corresponding to a 5.6 screw Corresponding to an 8.8 screw Higher tightening torques can cause deformation of the carrier ring and thus damage the seal Surfaces of the installation Plan area Rmax ≤ 15 µm Ra ≤ 3 µm Reusability The Usit ring can be damaged during dis- assembly. Freudenberg Sealing Technol- ogies therefore recommends replacing the Usit ring after disassembly. DESIGN NOTES tS Ø DM Ø dM Ø dS Ø dB S Fig. 320 Installation situation Usit-Ring I Counterbore For internally sealing Usit rings, Freuden- berg Sealing Technologies generally rec- ommends a counterbore for centering the Usit rings (exception: Usit rings with centering diaphragm). In addition, the counterbore also improves the pressure stability of the seals due to its support- ing effect (see → “Operating pressure,” page 632). No counterbore is required for externally sealing Usit rings, as the seal centers itself via the screw. Depth of counterbore (ts): 0.5 up to 1 Diameter of counterbore (Øds): (ØDM + 0.5) H13 Diameter In the case of internally sealing Usit rings, the inside diameter must be selected so that the sealing bead (taking into account the tolerances and eccentricity) does not extend into the through bore ØdB (note edge break ØdB!). It should be noted that the inside diameter of the Usit ring (ØdM) is reduced by approx. 0.6 during installa- tion. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 633 X E D N I

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Installation The bolted connections should be tight- ened without load (Usit rings are only loaded by the bolt force when tightened and not by the weight or spring stresses from the parts to be bolted). Otherwise, the increased friction can cause the Usit ring to rotate and damage the sealing lip (movement under high forces). This can occur when bolting a heavy plate overhead, for example. Static Seals 634

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14. Special Seals Website NOVOnox hygienic 14.5 HYGIENIC USIT PRODUCT BENEFITS y EHEDG-certified sealing system (Type EL – Class I AUX) y Gap-free sealing of screws flush with the product y Can replace expensive welded con- structions and special screws y Easy assembly y Frictional connection Matching screws and cap nuts in hygienic design are offered in cooperation with Heinrich Kipp Werke under the product name NOVOnox hygienic. Note The EHED G certificate refers to the use of screws from Heinrich Kipp Werke. Surfaces The mating surfaces and screws should have a roughness of Ra 0.8 µm (general requirement from the EHED G guidelines for cleanability of metal surfaces). Reusability The Usit ring can be damaged during dis- assembly. Freudenberg Sealing Technol- ogies therefore recommends replacing the Usit ring after disassembly. Stainless steel washer with an external vulcanized, rubber-elastic sealing bead. The sealing bead has a special, patented geometry that enables secure, gap-free and dead space-free contact with bolt heads according to DIN EN 1665 (toler- ance equalization). Available dimensions: M4 (special screw), M5, M6, M8, M10, M12, M16. AREAS OF APPLICATION Hygienic sealing of screw connections in the food and pharmaceutical industry. The seal prevents a medium from penetrating into the non-cleanable gaps under the screw head and the through hole of the screw bore. This prevents the formation of germs in these areas. It can be used in areas where the media are in contact with the screw connection (e.g. inside pumps, storage tanks and other equipment), in the vicinity of the equipment (e.g. inside isolators (sterile equipment)) or on the outside of appara- tuses and production halls. INSTALLATION AND ASSEMBLY Suitable screws The seal is designed for use with stainless steel screws according to DIN EN 1665. When selecting the screws, make sure that they are designed according to hygienic aspects (radii, no engravings, surfaces). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 635 X E D N I

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Static Seals MATERIAL Elastomer Metal ring COLOR TEMPERATURE RANGE [°C] AREAS OF APPLICATION 70 EPDM 291 1.4404 Black ‒40 … +150 Aqueous products 70 EPDM 253815 1.4404 White ‒40 … +150 Aqueous products 70 EPDM 217676 1.4404 Blue ‒40 … +150 Aqueous products 75 Fluoroprene XP 45 1.4404 Blue ‒20 … +200 Media containing fat or oil, special applica- tions (e.g. flavors) INSTALLATION The bolted connections should be tight- ened without load (Usit rings are only loaded by the bolt force when tightened and not by the weight or spring stresses from the parts to be bolted). Otherwise, the increased friction can cause the Usit ring to rotate and damage the sealing lip (movement under high forces). This can occur when screwing a heavy plate overhead, for example. Care must be taken to ensure that tightening is free of tilting. The following applies to screws from Heinrich Kipp Werke (NOVOnox hygienic) based on DIN EN 1665: PROPERTIES M4 M5 M6 M8 M10 M12 M16 Coefficient of friction [µges] 0.23 0.23 0.23 0.23 0.23 0.23 0.23 Bore diameter [mm] 4.05 5.05 6.05 8.05 10.05 12.05 16.05 Stress diameter [mm2] 8.78 14.2 20.1 36.6 58 84.3 157 Preload force FV [N] 1,405 2,272 3,216 3,856 9,280 13,488 25,120 Tightening torque MA [Nm] 2.03 3.87 6.55 15.63 30.63 53.51 131.43 If a different bolt is selected, the preload force must be ensured. 636

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14. Special Seals PRODUCT BENEFITS y High chemical resistance • Reliable use in CIP/SIP media • Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 y Standard dimensions available from stock, without tooling costs offers customized components that are designed by its experts specifically for the customer’s application. 14.6 CLAMP SEALS FOR THE PROCESS INDUSTRY Clamp seals are rotationally symmetrical sealing rings for static sealing of flange connections according to DIN 32676. Due to the symmetrical geometry, clamp connections can be installed and sepa- rated very easily.Thanks to standardiza- tion in accordance with DIN 32676, the seals are standardized and therefore particularly economical and available from stock. Dimensions of conventional clamp seals according to DIN 32676 y series A: (metric) nominal dimensions from DN6 – D N 200 y series B: D N/OD 10.2 – D N/OD 219.1 y series C: (inch) from 1/4" to 6" To meet the special requirements of the food and pharmaceutical industries, Freudenberg Sealing Technologies has developed a portfolio consisting of four materials. This covers all the requirements of the process industry and at the same time saves tooling costs. Note If special shapes are required (defined pressing, function integration, other ma- terials), Freudenberg Sealing Technologies I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 637 X E D N I

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Static Seals MATERIAL COLOR TEMPERATURE RANGE [°C] APPLICATION APPROVALS 70 EPDM 291 Black ‒40 … +150 media; acids; alkalis; Aqueous (polar) water vapor FDA 21 CFR 177.2600, Reg. (EC) 1935/2004, 3-A® Sanitary Stand- ards Class II, USP Ch. 87, USP Ch. 88 – Class VI – 121 °C, NSF 51, ADI free 70 EPDM 253815 White ‒40 … +150 media; acids; alkalis; Aqueous (polar) water vapor FDA 21 CFR 177.2600, Reg. (EC) 1935/2004, 3-A® Sanitary Stand- ards Class II, USP Ch. 87, USP Ch. 88 – Class VI – 121 °C, ADI free 75 Fluoroprene XP 41 Blue ‒15 … +200 70 VMQ 117055 Transparent ‒50 … +200 Polar and non-polar media (e.g. fatty foods); aromas FDA 21 CFR 177.2600, Reg. (EC) 1935/2004, 3-A® Sanitary Stand- ards Class I, USP Ch. 87, USP Ch. 88 – Class VI – 121 °C, NSF 51, ADI free Customized applications. Not recommended for aqueous media and high temperatures FDA 21 CFR 177.2600, Reg. (EC) 1935/2004, 3-A® Sanitary Stand- ards Class I, USP Ch. 87, USP Ch. 88 – Class VI – 121 °C, ADI free 638

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14. Special Seals 14.7 DAIRY COUPLING SEALS FOR THE PROCESS INDUSTRY PRODUCT BENEFITS y High chemical resistance • Reliable use in CIP/SIP media • Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 CIP/SIP Guide Dairy coupling seals are rotationally sym- metrical sealing rings for static sealing of flange couplings according to DIN 11851. Note Dairy coupling seals are available on re- quest according to the above standard. If special shapes are required (deviating geometry, function integration, other materials), the field service will be happy to offer customized components that are specially adapted to the customer’s ap- plication by FST experts. Dairy coupling seals can be used to easily connect and seal pipe connections for liquid media. They are very common in the food industry. Their main advantage is extremely quick and easy installation thanks to their easy separation from the flange so that they can also be frequently disassembled without difficulty. Variants y standard form, version with a lip and a high version y nominal dimensions from D N 15 to D N 100 Standard With lip High version I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 639 X E D N I

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Static Seals 14.8 CUSTOMIZED FLANGE SEALS FOR THE PROCESS INDUSTRY Hygienic flange seals are static seals used to seal customer-specific pipe connections and housings. Based on the customer’s applications and groove geometries, the seals are designed according to the EHED G Hygienic Design Guidelines. Methods such as FEM calculations are used to achieve a flush seal without dead spaces. PRODUCT BENEFITS y Hygienic sealing with high durabil- ity, according to EHED G guidelines • High chemical resistance • Reliable use in CIP/SIP media y Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 y Fine-tuning of the seal to the tem- peratures and pressures occurring during use y Exclusive, customer-specific seal that only you can purchase For this reason, specific clarification of all relevant framework parameters is neces- sary. Please ask your contact for the EIS-sheets (Engineering Information Sheets). Fig. 322 Customized flange seal Note These are usually customer-specific com- ponents that are adapted to the customer application by the experts using the FST design guidelines. 640

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14. Special Seals AREA OF APPLICATION TEMPERATURE RANGE [°C] PRESSURE [bar] AREAS OF USE –20 … +200 Max. 150 Common CIP/SIP media; beverages; food; chemical products MATERIAL COLOR TEMPERATURE RANGE [°C] APPLICATIONS APPROVALS 70 EPDM 291 Black ‒40 … +150 75 Fluoroprene XP 41 Blue ‒15 … +200 Other materials on request. Aqueous (polar) media; acids; alkalis; water vapor Polar and non-polar media (e.g. fatty foods); aromas FDA 21 CFR 177.2600, Reg. (EC) 1935/2004, 3-A® Sanitary Stand- ards Class II, USP Ch. 87, USP Ch. 88 – Class VI – 121 °C, NSF 51, ADI free FDA 21 CFR 177.2600, Reg. (EC) 1935/2004, 3-A® Sanitary Stand- ards Class I, USP Ch. 87, USP Ch. 88 – Class VI – 121 °C, NSF 51, ADI free I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 641 X E D N I

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Static Seals 642 PRODUCT BENEFITS y Cost reduction of the overall system: • Easier and safer assembly • No grooves required for mounting seals • Simplification of the system through component reduction (including low logistics costs) • Automation of assembly possible y Higher system reliability: • Clearly defined grouting of the seal • High-pressure sealing possible • Simple assembly check possible (seal present/not present) • Rigid sealing element (single, auto- mated assembly possible) For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). 14.9 SEALING SHEETS/ EDGE BONDED GASKETS Sealing sheets/edge bonded gaskets con- nect several, often different sealing geom- etries with each other. In principle, sealing sheets consist of a carrier part (e.g. stamped metal sheet) with edge bonded sealing lips. Several sealing elements (e.g. O-rings) are combined in a single component. The design with the carrier part guarantees defined compression of the sealing beads, almost independent of the tightening torque of the connecting screws. APPLICATION Hydraulic systems, engines and transmis- sions, auxiliary units. INSTALLATION AND ASSEMBLY Installation is between two flat surfaces (specify flatness) with defined roughness (recommended max. Rz 16). Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all relevant framework parameters is required.

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14. Special Seals MATERIAL Elastomer part Carrier part NBR; EPDM; FKM; HNBR Aluminum; steel; brass; plastic TEMPERATURE RANGE [°C] PRESSURE [bar] AREA OF APPLICATION ‒40 … +180 Max. 250 … 400; in special cases up to 800 Hydraulic media; mineral oils; fuels Other materials (e.g. VMQ) on request. The materials of the carrier part and the elastomer must always be selected to suit the application conditions. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 643 X E D N I

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I S P E C A L S E A L I N G P R O D U C T S 6 4 5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING INTRODUCTION & SERVICES

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648 660 661 661 662 663 664 666 668 670 672 674 676 683 694 700 703 703 703 703 704 705 706 707 Special Sealing Products TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. Function and Expansion Potentials Unique Materials Expertise Areas of Application ELASTOMER COMPOSITE PARTS/ PRECISION MOLDED PARTS/ PTFE SEALING SOLUTIONS 2.1 2.2 2.3 2.4 Carrier Parts 2.5 2.6 2.7 2.8 2.9 2.10 Micro and miniature parts/Simriz® molded and composite parts 2.11 2.12 Profiles, Cords and Hoses 2.13 Magnetic Anchors and Valve Bodies Hygienic Pressure Seal (HPS) Butterfly valve seal for the Process Industry Radial and axial seals for seat valves in the Process Industry Stem seals for seat valves in the Process Industry Plug & Seal Connectors Sheets, circular blanks and sheeting 3. CUSTOMIZED INTEGRATED PRECISION SOLUTIONS WITH PLASTIC 3.1 Areas of Application/ Uses Cover & Seal Fluid Connect Circuit Protect Information needed to respond to requests Application example – Fluid connect – pipes Application example – Fluid connect – Assembly injection molding (moving subcomponents) Application example – Circuit protect – carrier including the seal and an additional function 3.2 3.3 3.4 646

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6 4 7 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING T a b l e o f C o n t e n t s INTRODUCTION & SERVICES

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Special Sealing Products 1. PRODUCT OVERVIEW 648 PRODUCT GROUPDESIGN DESCRIPTIONMAIN APPLICATIONSElastomer composite and precision molded partsHygienic Pressure Seal (HPS)A HPS consists of an elastomeric compression ring and a PTFE ring made of a filled high- performance PTFE with approval for foodstuffsHygienic Pressure Seals (HPS) are mainly used in seat valves in the Process IndustryButterfly valve sealRotationally symmetrical seals that seal dynamically to the valve disk of a butterfly valve on the inside diameter and have static sealing geometries on the face sides that seal the valve flanges against each other. Furthermore, sealing geometries for the opera-tional shafts are providedButterfly valves in pro-cess plants and systems; process plants in the Beverage Industry, the Dairy Industry and the Chemical and Pharma-ceutical IndustryRadial seals for seat valvesRotationally symmetrical seals with a dynamic sealing geometry for sealing the valve seat. Axially, the seals are equipped with fur-ther sealing geometries in order to statically seal the installation in the valve disk and thus prevent back migrationSeat valves in the Process IndustryStem seals for seat valvesRotationally symmetrical, L-shaped seals. One limb is equipped with a sealing geometry to seal dynami-cally towards the valve stem. The other leg is used to anchor the seal in the valve bodySeat valves in the Process Industry

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1. Product Overview Further information on our product portfolio I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 649 X E D N I MATERIALMAX. TEMPERATURE RANGE [°C] *STANDARD CATALOG RANGEFREUDENBERG XPRESS®85 EPDM 302; 75 Fluoroprene XP 41; Quantum PTFE F18245‒20 … +150NoYesEPDM; 75 Fluoroprene XP 41; VMQ; HNBR‒20 … +150 depending on the materialNoNoEPDM; 75 Fluoroprene XP 41; HNBR‒20 … +150 depending on the materialNoYesEPDM; 75 Fluoroprene XP 41; HNBR‒20 … +150 depending on the materialNoYes

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Special Sealing Products PRODUCT GROUP Elastomer composite and precision molded parts DESIGN DESCRIPTION MAIN APPLICATIONS Plug & Seal connectors Plug & Seal connectors are rubberized pipe sections with sealing beads and shock absorbers on the outer surface Micro or miniature parts Small and extremely small elas- tomer composite parts and molded parts developed individ- ually for customers (< 20 mm). Can be manufactured in a wide variety of materials and designs. Thin wall thicknesses in the range of a few tenths of a millim- eter can be realized, as well as tight tolerances in the range of a few hundredths of a millimeter Connections between housings or aggregates such as water/oil circuits of combustion engines; thermal management of hybrid or e-vehicles in battery, motor and in- verter or fluid systems, mechanical engineering Fluid control systems in medical, analytic technol- ogy and biotechnology; solenoid valves; process technology; hydraulics and pneumatics Sheets and sheeting Sheets can be manufactured as pure elastomer sheets as well as with a fabric layer (one side, center) or a PTFE layer (one side) In most cases, they are further processed into flat seals or diaphragms Profiles, cords, hose rings Profiles, cords or hose rings pro- duced in an extrusion process Special profiles, cords or hoses are used to seal large sealing points that cannot be sealed with molded seals or O-rings, or when these are cost-prohibitive 650

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H No No EPDM FKM AEM NBR HNBR ‒40 … +140 ‒10 … +220 ‒25 … +150 ‒30 … +90 ‒30 … +140 ‒35 … +200 R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B EPDM; FKM; FFKM depending on the ma- No No terial NBR; SBR; CR; ACM; VMQ; FVMQ; EPDM; HNBR; FKM; FFKM Depending on the material Yes No NBR; EPDM; VMQ; FKM; other materials on request Depending on the material Yes Yes (depend- ing on the profile) S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 651 X E D N I

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Special Sealing Products DESIGN DESCRIPTION MAIN APPLICATIONS Lifting anchor Within a guide mechanism, flexible lifting anchors combine the sealing and damping function in a single component Pneumatic valves in the automotive sector, for household appliances or in general industry, through to hydrogen applications Tilt anchor Axially fixed anchors made of different carrier materials allow fast switching times and sustainable process optimization Mounted magnetic anchor Magnetic anchors with mounted valve bodies or sealing/damper elements Meander springs Magnetic anchors in meander spring form with sealing and damping functions allow minimum strokes at high frequencies in the smallest possible space Pneumatic valves, e.g. in rice sorting plants All types of applications, especially in the use of highly dynamic applications, very high-mass anchors and systems with the highest accuracies Valves in liquids or gases for various applications, such as engine injection or tools PRODUCT GROUP Magnetic anchors 652

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® Various Depending on the material No No Various Depending on the material No No Various Depending on the material No No Various Depending on the material No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 653 X E D N I

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Special Sealing Products PRODUCT GROUP 2K components DESIGN DESCRIPTION MAIN APPLICATIONS Cover & Seal Fluid Connect Complex housing or carrier parts with integrated static or dynamic seal to protect sensitive components (mechatronics, electrical, sensors) Thermoplastic components and pipes for guiding, conducting and controlling fluids in valves or for con- necting aggregates, partly with integrated static and dynamic seals Mechatronics, electrical and sensor technology requiring protection in the automotive sector and general industry Thermal management; oil/cooling circuits; valves Circuit Protect Components made of thermoplastic materials or insulating seals for low- to high-voltage applications and battery applications Electrical wiring; pin/connector feedthroughs; sensor protection; battery parts 654

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® PA; PBT; PPA; PPS; bonded with NBR, FKM, AEM, EPDM, thermoplastic elasto- mers, liquid silicone, etc. PA; PBT; PPA; PPS; bonded with NBR, FKM, AEM, EPDM, thermoplastic elasto- mers, liquid silicone, etc. PA; PBT; PPA; PPS; bonded with NBR, FKM, AEM, EPDM, thermoplastic elasto- mers, liquid silicone, etc. Depending on the material No No Depending on the material No No Depending on the material No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 655 X E D N I

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Special Sealing Products DESIGN DESCRIPTION MAIN APPLICATIONS Back-up ring SRA Split back-up ring with a rectangular cross-section for externally-sealing O-rings Valves; cylinders Back-up ring SRI Split back-up ring with a rectangular cross-section for internally-sealing O-rings Valves; cylinders Back-up ring SPR Helic split bearing component with a rectangular cross-section Valves; cylinders Usit I, A, I SF Metal flat gasket with internal or external edge bonded, trapezoi- dal, rubber-elastic sealings (seal- ing washer). Design as internally or externally sealing Bolted joints in general mechanical engineering Hygienic Usit Stainless steel washer with external edge bonded, rubber- elastic sealing geometrie Hygienic sealing of screw connections in the food and pharma- ceutical sectors Clamp seals Clamp seals are rotationally symmetrical sealing rings for static sealing of flanged joints according to DIN 32676 Flanges in the Process Industry PRODUCT GROUP Static seals For further information, please see → chapter “Static seals”, page 628 656

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® PTFE F52800; PTFE 177509 ‒70 … +260 (PTFE element) PTFE F52800; PTFE 177509 ‒70 … +260 (PTFE element) PTFE F52800; PTFE 177509 ‒70 … +260 (PTFE element) Yes Yes Yes Yes Yes Yes 70 NBR 177646 ‒30 … +100 75 FKM 177645 ‒30 … +200 70 EPDM 291 ‒40 … +150 70 EPDM 253815 ‒40 … +150 70 EPDM 217676 ‒40 … +150 75 Fluoroprene XP 41 ‒20 … +200 70 EPDM 291 ‒40 … +150 70 EPDM 253815 ‒40 … +150 75 Fluoroprene XP 41 ‒15 … +200 70 VMQ 117055 ‒20 … +200 Yes No Yes No Yes Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 657 X E D N I

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Special Sealing Products DESIGN DESCRIPTION MAIN APPLICATIONS Dairy coupling seals Seals for dairy couplings are rotationally symmetrical sealing rings for the static sealing of flanged joints according to DIN ISO 11851 Dairy couplings in the Process Industry Hygienic flange seals Hygienic flange seals are static seals for sealing customer-specific pipe connections and housings Pipe connections and housings in the Process Industry FOI FOA Axially moving PTFE rod seal with a metallic tension spring, interchangeable for O-ring installation spaces, internally sealing design as a rod seal Axially moving rod seal made of PTFE with a metallic tension spring, interchangeable for O-ring installation spaces, externally sealing version as a piston seal Hot water valves; pneumatic cylinders Hot water valves; pneumatic cylinders Micro Simmerring® Micro Simmerring® for rotary applications with shaft diame- ters 1–3 mm Sealing cap GA Sealing cap with a press fit – standard version (rubber outside) Use in demanding, cus- tomer-specific mini ature applications such as micro pumps, micro drives and micro actuators Earthmoving equipment; industrial/forklift trucks; agricultural equipment; truck-mounted cranes Sealing cap GSA Sealing cap with press fit – special version with rubber/ steel outside Drillings and assembly guides in housings; general mechanical engineering PRODUCT GROUP Static seals For further information, please see → chapter “Static seals”, page 639 Translational sealing elements For further information, please see → chapter “Seals for fluid power applications,” page 533 Rotary seals For further information → chapter “Seals for rotary applications,” page 410 658

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG FREUDENBERG RANGE [°C] * RANGE XPRESS® EPDM; 75 Fluoroprene XP 41; VMQ; HNBR ‒40 … +200 depending on the ma- No Yes terial 70 EPDM 291 ‒40 … +150 75 Fluoroprene XP 41 ‒15 … +200 No Yes PTFE F56110; 1.4310 stainless steel spring ‒200 … +260 Yes Yes PTFE F56110; 1.4310 stainless steel spring ‒200 … +260 Yes Yes EPDM; NBR; FKM; ‒35 … +200 FFKM; 75 Fluoroprene depending on the ma- No No XP 41 terial 75 NBR 99004 ‒40 … +100 Yes No 75 NBR 99004 ‒40 … +100 Yes No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 659 X E D N I

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Special Sealing Products 2. ELASTOMER COMPOSITE PARTS/ PRECISION MOLDED PARTS/ PTFE SEALING SOLUTIONS Process technology Materials expertise Application- Know-how Market segments Innovative concepts for customer-specific solutions via know-how transfer Fig. 323 Tailored offerings to meet segment-specific requirements FST Website Special Sealing Products Elastomer composite and precision-molded parts as well as PTFE seals from Freuden- berg Sealing Technologies (hereinafter also abbreviated FST) provide customers with tailor-made and functionally opti- mized sealing solutions, even for complex applications. State-of-the-art materials technology and innovative product and tool design processes ensure precise implementation of the desired component. Product catalog In addition to a wide range of standard products, Freudenberg Sealing Technologies also offers special seals. Special seals are often customer-specific solutions with special dimensions or appli- cation requirements. Since they are usu- ally designed and manufactured individ- ually, they require a sealing solution expert with excellent material, product and application know-how. Freudenberg Sealing Technologies is the expert in this field and offers the highest level of tech- nical expertise in consulting, engineering and manufacturing. Freudenberg Sealing Technologies com- bines material, process and application expertise and applies this knowledge segment-specifically to produce a tailor- made solution for its customers. 660

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions I & N O T C U D O R T N S E C I V R E S I 2.1 FUNCTION AND 2.2 UNIQUE MATERIALS EXPANSION POTENTIALS EXPERTISE Freudenberg Sealing Technologies prod- ucts can perform other functions in ad- dition to the actual “sealing function.” The following is an overview of possible potential for equipping the seal with ad- ditional functions. Special sealing products can be produced from a wide variety of materials and are generally adapted to specific customer requirements. More than 1,800 different materials are available for this purpose. Freudenberg Sealing Technologies’ portfo- lio includes materials with approvals for the food, pharmaceutical, drinking water, gas and electrical industries, among others. Further information on FST materials can be found in the → chapter “Materials and process engineering”, page 29. Optimization potentials Installation Installation Safety Facilitation Automation Help Serviceability Surface finish Friction Rotation Linear movement Assembly Forces Wear Dry running Connections Noises/ vibrations Function integration Electronics Decoupling Assembly Contamination Pressure Permeation Aggregates Standards/Laws Destruction Influence on third parties High frequencies Damping Partial reduction Installation space Installation Rejects Cost reduction Module D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Surroundings Media Temperature Contamination Forces Migration Lifetime Media Aging Wear Destruction Temperature S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 324 Optimization potentials in the design of customer-specific products 661 X E D N I

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Special Sealing Products 2.3 AREAS OF APPLICATION Innovative elastomer composite and pre- cision molded parts as well as PTFE seals from FST are used in nearly all areas of the automotive industry and general industry wherever standard industry solutions cannot be optimally applied. The follow- ing areas of application are only a small selection of the many possible uses. FUEL SUPPLY PNEUMATIC SYSTEMS y Automotive industry y General industry y Composite parts y Precision molded parts L O R T N O C D U L F I SEATING COMFORT SYSTEMS AIR SUSPENSION SYSTEMS y Automotive industry y General industry y Passenger cars y Trucks and buses EMISSION REDUCTION FTIV y EGR – exhaust gas recirculation y SCR – selective catalytic reduction y Tank shut-off valves for plug-in hybrids T R O F M O C S N O I S S I M E Tab. 44 Overview of magnetic anchor applications/products 662

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A FOOD & BEVERAGE FLUID HANDLING ENERGY y Filling systems y Separators y Dispensers y Valves y Pumps y Controllers y Blade/tower bearing y Offshore foundations y Electrical switchgears y Solar y Clamp seals y Seals for double and single-seat valves y Rod seals y Radial seals y DSF y Hygienic Line y Micro formed parts y PTF E seals y Micro Simmerrings y Elastomer composite parts y Sealing caps y Offset seals y Plug & Seals y PTF E Forseal y Oil passage seal N O I T A C I L P P A S T C U D O R P Tab. 45 Overview of applications/products for general and process industry 2.4 CARRIER PARTS Carrier parts made of metallic materials or plastics are used in special sealing prod- ucts when rubber elasticity and rigidity are required within a component. Elastomers can be bonded mechanically or chemically to metals or plastics. More detailed and in-depth information about carrier parts can be found in the → chapter “Materials and process engi- neering – 6. Carrier parts”, page 123. R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 663 X E D N I

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Special Sealing Products 2.5 HYGIENIC PRESSURE SEAL (HPS) PRODUCT BENEFITS y Outstanding operational performance • Sealing without dead space • Small contact area to the process medium • Good dry running properties • Excellent sealing behavior • Excellent pressure stability • Low friction y Long service life due to reduced wear y Reduced operational forces y High chemical resistance • Reliable use in CIP/SIP media • Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 y As a rule, prototypes can be pro- duced in small quantities without tooling costs (turned parts) APPLICATION Seat valves in process plants and systems, process plants in the beverage industry, dairy industry and the chemical and phar- maceutical industry, micro-dosing pumps. MATERIAL The materials used are primarily FDA-, BFR- and USP Class VI-tested or ATEX-cer- tified elastomer compounds based on VMQ, EPDM, Fluoroprene XP and HNBR. The sealing material must always be se- lected to suit the application conditions. Hygienic Pressure Seals (HPS) are mainly used in seat valves in the process industry, where they perform a similar function to stem seals. However, rotary applications are also conceivable. HPS is a solution from Freudenberg Seal- ing Technologies for hygienic sealing at higher pressures. An HPS consists of an elastomeric com- pression or energizer ring and a PTFE ring made of a filled high-performance food- grade PTFE. The elastomer ring seals statically against the installation groove and the PTFE. The PTFE ring takes over the dynamic sealing function towards the rod and also acts as a back-up ring. In the rear area, a compensation space is created in the installation groove to com- pensate for thermal expansion. The special design allows sealing of high pressures (up to 150 bar) over a wide tem- perature range. 664

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions AREA OF APPLICATION TEMPERATURE RANGE [°C] PRESSURE [bar] AREA OF APPLICATION –20 … +150 Max. 150 Common CIP/SIP media; beverages; food; chemical products Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all relevant framework parameters is required. For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 665 X E D N I

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Special Sealing Products 2.6 BUTTERFLY VALVE SEAL FOR THE PROCESS INDUSTRY Butterfly valve seals are used as seals in fly valves in process engineering plants. The elastomer molded ring is radially compressed in the valve during the closing process and thus seals high- and low-vis- cosity media. Low friction and a low compression set of the valve seal as well as high temper- ature and media resistance, explicitly also in cleaning media (CIP/SIP – Cleaning In Place/Sterilization In Place), are decisive for perfect functioning. APPLICATION Disk valves in process plants and systems. Process plants in the beverage industry, the dairy industry, and the chemical and pharmaceutical industries. MATERIAL The materials used are primarily FDA-, BFR- and USP Class VI-tested or ATEX- certified elastomer compounds based on VMQ, EPDM, Fluoroprene and HNBR. In addition, special high-performance elas- tomers made of Simriz® can be offered for customized applications. The butterfly valve seal material must al- ways be selected based on the operating conditions. PRODUCT BENEFITS y Outstanding operational performance • High functional reliability • Optimized service life • Low frictional torques during ac- tuation • Very good sealing behavior y A wide range of applications • Functionality within a wide tem- perature range • Wide range of materials tailored to the most diverse applications • Ensures a maximum number of switching cycles • Application in many media with corresponding approvals y High chemical resistance • Reliable use in CIP/SIP media • Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all relevant framework parameters is required. For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). CIP/SIP Guide 666

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions AREA OF APPLICATION TEMPERATURE RANGE [°C] PRESSURE [bar] AREA OF APPLICATION ‒20 … +150 Max. 25 Common CIP/SIP media; beverages; food; chemical products EPDM VMQ HNBR FKM I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P MATERIAL SELECTION MEDIA DVR Sliding properties Aqueous media Steam CIP/SIP +++ +++ +++ +++ +++ Dairy products D … + Hydrocarbons, aliph. Hydrocarbons, arom. Essential oils/citrus juices Hot wort +++ excellent ++ + recommended usable – – D ++ D conditionally usable − unsuitable +++ + +++ D ++ + + – D – + + + + + +++ ++ ++ + ++ + + + + + +++ +++ +++ + – S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 667 X E D N I

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Special Sealing Products 2.7 RADIAL AND AXIAL SEALS FOR SEAT VALVES IN THE PROCESS INDUSTRY Radial seals are used in seat valves in the process industry. They perform the dy- namic sealing function in the sealing seat of the valve and thus separate the various media in the process when the valve is closed. In the patented design from Freudenberg Sealing Technologies, the dynamic seal- ing function in the valve seat and the static sealing function towards the valve disc are decoupled by a reusable carrier ring. This allows both sealing functions to be optimized independently of each other. PRODUCT BENEFITS y Outstanding operational performance • High functional reliability • Optimized service life • Excellent sealing behavior • Low switching forces at elevated temperatures y A wide range of applications • Functionality within a wide tem- perature range • Wide range of materials tailored to the most diverse applications • Ensures a maximum number of switching cycles • Can be put to use in many media with the corresponding approvals y High chemical resistance • Reliable use in CIP/SIP media • Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 Furthermore, it is possible to create securely sealed displacement spaces to compensate for thermal expansion. This creates a sealing system whose contact force is nearly independent of tempera- ture and material swelling and compen- sates for manufacturing tolerances quite well. The design is produced using FEM calcu- lations. Solutions with split valve discs or with unsplit valve discs are possible. Fig. 325 Radial seal in FST design 668

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions AREA OF APPLICATION TEMPERATURE RANGE [°C] PRESSURE [bar] AREA OF APPLICATION –20 … +150 Max. 25 Common CIP/SIP media; beverages; food; chemical products APPLICATION Seat valves in process plants and systems. Process plants in the beverage industry, the dairy industry, and the chemical and pharmaceutical industries. Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all rel- evant framework parameters is necessary. For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). MATERIAL The materials used are primarily FDA-, BFR- and USP Class VI-approved or ATEX- certified elastomer compounds based on VMQ, EPDM, Fluoroprene XP and HNBR. In addition, special high-performance elastomers made of Simriz® can also be offered for customer-specific applications. The radial seal material must always be selected to suit the conditions of use. Standard design Factor 1 0 °C Factor 2 50 °C Design by Freudenberg Sealing Technologies Factor 1 0 °C Factor 1.1 100 °C Nearly constant contact voltage over double temperature range Fig. 326 FEM calculation using the example of a radial seal I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 669 X E D N I

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Special Sealing Products 2.8 STEM SEALS FOR SEAT VALVES IN THE PROCESS INDUSTRY Stem seals are used in seat valves in the process industry. They perform a dynamic sealing function there, whereby the outlet of the valve’s drive shafts from the valve is sealed. The seal prevents both leakage of the pro- cess medium into the environment of the valve and the ingress of contamination from outside the valve into the process medium. In most cases, these seals have an L-shaped profile. APPLICATION Seat valves in process plants and systems. Process plants in the beverage industry, the dairy industry, and the chemical and pharmaceutical industries. 670 PRODUCT BENEFITS y Outstanding operational performance • High functional reliability • Optimized service life • Excellent sealing behavior y Wide range of applications • Functionality within a wide tem- perature range • Wide range of materials tailored to the most diverse applications • Ensures a maximum number of switching cycles • Use in many media with the cor- responding approvals y High chemical resistance • Reliable use in CIP/SIP media • Resistance to flavors y Material selection for a wide range of approvals, e.g. F D A, Reg. (EC) 1935/2004 MATERIAL The materials used are primarily FDA-, BFR- and USP Class VI-approved or ATEX- certified elastomer compounds based on VMQ, EPDM, Fluoroprene XP and HNBR. In addition, special high-performance elastomers made of Simriz® can also be offered for customer-specific applications. The shaft seal material must always be selected to suit the operating conditions.

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions AREA OF APPLICATION TEMPERATURE RANGE [°C] PRESSURE [bar] AREA OF APPLICATION –20 … +150 Max. 25 Common CIP/SIP media; beverages; food; chemical products Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all rel- evant framework parameters is necessary. For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 671 X E D N I

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Special Sealing Products 2.9 PLUG & SEAL CONNECTORS Plug & Seal connectors are rubberized pipe sections with sealing beads and stop dampers on the outer surface. They are used to create a tight connection between two housings or units – for the reliable transport of media such as oils, water or air. Plug & Seal connectors are always de- signed for the individual customer appli- cation, tailored to the respective require- ments for assembly, installation space, media, temperature and pressure load. APPLICATION y water and oil circulation or air flow PRODUCT BENEFITS y Reliable sealing even at high pres- sures y Easy, safe and cost-effective as- sembly y Acoustic and mechanical decoupling y Reduced maintenance due to im- proved durability y Center offset compensation y Compensation for misalignment allows larger tolerances of mating partners y Low logistics costs due to the inte- gration of several functions in one component, resulting in lower overall costs y Design development according to customer specific requirements INSTALLATION AND ASSEMBLY Specifications for the condition of the installation space: systems of combustion engines y surface roughness R: y thermal management systems of hy- brid and electric vehicles in batteries, e-motors and inverters. y engine auxiliaries, such as compressors, turbochargers or intake manifolds y fluid systems in special systems and mechanical engineering MATERIAL Pipe section: According to customer-spe- cific requirements, e.g. in steel, aluminum or plastic. Seal: According to customer-specific re- quirements, e.g. in EPDM, FKM, AEM, ACM, NBR, HNBR. static pressures Rmax < 16 µm, pulsating pressures Rmax < 6 µm y tolerance ISO H8 y recommended lead-in chamfer: • chamfering of at least 20°, • chamfer length (a) approx. 2 mm, • edges burr-free and rounded y depth of the installation space (t1): ≥ 7 mm y max. axial offset after consultation 672

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions AREA OF APPLICATION Plug & Seal connectors withstand pressures up to max. 10 bar. Higher pressures on request. ELASTOMER MEDIA TEMPERATURE RANGE AREA OF APPLICATION [°C] EPDM Not oil resistant ‒40 … +140 Oil resistant ‒10 … +220 Oil resistant ‒25 … +150 Cooling water; brake fluid; aqueous media Charge air with oil compo- nents; cooling water; fuels such as diesel, biodiesel, gasoline Charge air with oil compo- nents; engine oil I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P FKM AEM ACM NBR Oil resistant ‒25 … +150 Engine oil Oil resistant ‒30 … +90 Gear oil HNBR Oil resistant ‒30 … +140 Gear oil; engine oil; diesel fuel C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 673 X E D N I

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Special Sealing Products 2.10 MICRO AND MINIATURE PARTS/SIMRIZ® MOLDED AND COMPOSITE PARTS Small and very small elastomer composite parts and molded parts developed to cus- tomer specifications (< 20 mm). Can be manufactured in a wide variety of mate- rials and designs. Thin wall thicknesses in the range of a few tenths of a millimeter can be realized, as well as tight tolerances in the range of a few hundredths of a mil- limeter. Simriz® (FFKM) can be used for very high media resistance requirements. For example, the components can fulfill a static sealing function (sealing of a cover against a housing), separate media or, by means of mechanical adjustment (axial adjustment/tilting), assume a switching function in the form of opening/closing of inlet and outlet bores. It is feasible to combine these functions into a single component. APPLICATIONS Fluid control systems in medical, analyt- ical and biotechnology, solenoid valves, process technology, hydraulics and pneu- matics, for example. PRODUCT BENEFITS y Customized miniature parts/sealing components in a wide variety of materials and designs y High product quality and precision due to special manufacturing y Versatile application possibilities y Very high media and temperature resistance when using Simriz® ma- terials y High assembly and failure safety y The functions of static sealing, sep- aration of media and switching can be combined MATERIAL Innovative and precise tool concepts, maximum precision in terms of tool man- ufacture, tool surfaces and process control, minimum shot weights and the possibility of applying finishes to the finished part to prevent adhesion of the elastomer. Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all rel- evant framework parameters is necessary. For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). 674

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions MATERIAL Elastomer part Carrier part TEMPERATURE AREA OF APPLICATION RANGE [°C] Steel; stainless steel; brass Plastics, such as PA6.6, PEEK, with glass or carbon fiber reinforcement Plastics in different colors to avoid confusion Max. +260 (Simriz®) Mineral oils; hydraulic fluids; CIP/SIP media; chemicals for rinsing and cleaning in labo- ratory analysis equipment; hot water EPDM; FKM; Simriz® Other materials on request I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 675 X E D N I

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Special Sealing Products 2.11 SHEETS, CIRCULAR BLANKS AND SHEETING PRODUCT ADVANTAGES By selecting the elastomer, fabric and foil made of PTFE, the characteristic properties of the sheets can be indi- vidually adjusted to the desired appli- cation. No additional material costs are incurred in the manufacture of sheets and sheeting. By producing the sheeting in a width of 500 mm, the tightest tolerances can be produced. y sheets with a fabric insert: • both sides delivered with untreated surface as pressed in the molding tool • thinnest sheet thickness: 2 x 0.5 mm + fabric thickness y sheets with a PTF E overlay: • one side delivered with untreated surface as pressed in the molding tool, opposite side foil made of PTFE • thinnest sheet thickness: 0.5 mm + overlay made of PTFE The surface quality of the rubber surfaces can be influenced by grinding or using other suitable processes. Sheets in other variants available on request. APPLICATION Parts made from sheets are used in virtu- ally all branches of industry, e.g. machine and aircraft construction. MATERIAL All common elastomer materials from FST are processed. The choice depends on the respective application. Sheets and circular blanks can be manu- factured as pure elastomer sheets or with a fabric layer (on one side, in the center) or a PTFE layer (on one side). In most cases, they are further processed into flat gaskets or membranes. y circular blanks (elastomer only): • both sides delivered with untreated surface as pressed in the molding tool • smallest circular blank thickness: 0.5 mm y circular blanks with fabric reinforce- ment or PTF E foil: • both sides delivered with untreated surface as pressed in the molding tool • smallest circular blank thickness: 0.8 mm y sheets (elastomer only): • both sides delivered with untreated surface as pressed in the molding tool • smallest sheet thickness: 0.5 mm Thinner sheets are possible on request, depending on the material. y sheets with a fabric overlay: • one side delivered with untreated surface as pressed in the molding tool, opposite side fabric • thinnest sheet thickness: 0.5 mm + fabric thickness 676

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions AREA OF APPLICATION MEDIA Depending on the material selection TEMPERATURE Depending on the material, between –50 °C and +200 °C I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H SHEETS WITH A FABRIC OVERLAY SHEETS WITH A FABRIC INSERT SHEETS WITH A PTFE OVERLAY DESIGN INFORMATION Tolerances of sheet products SHEETS 150 x 152 mm Are used for one-sided increased pressure load Are used when there are increased pressure loads on both sides Are used when the highest chemical resistance is needed, when the surface should be smooth and repellent to foreign substances, when low coefficients of friction are necessary R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P PRESSED SHEETS MATERIAL FFKM MATERIAL THICKNESS [mm] TOLERANCES [mm] 0.75 ± 0.1 No grinding of the sheets possible No fabrics or foils for pressed sheets Current production of a sheet with the thickness 0.75 mm. Different thicknesses on request SHEETS 200 x 200 mm PRESSED SHEETS MATERIAL FFKM MATERIAL THICKNESS [mm] TOLERANCES [mm] 1 and 1.5 ± 0.1 No grinding of the sheets possible No fabrics or foils for pressed sheets Current production of a sheet with the thickness 0.75 mm C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 677 X E D N I

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Special Sealing Products SHEETS 350 x 350 mm MATERIAL MATERIAL THICKNESS [mm] TOLERANCES TOLERANCES* [mm] PRESSED SHEETS GROUND ON ONE SIDE NBR CR ACM VMQ FVMQ EPDM HNBR FKM 0.5 … 4 0.5 … 1.0: ± 0.1 mm > 1.0 mm: ± 10 % 0.5 … 4.0: ± 0.10 * Tighter tolerances up to ± 0.05 possible on request SHEETS 500 X 500 mm FROM SHEETING (MINIMUM QUANTITY: 100 SHEETS) ROLLERHEAD ROLLERHEAD WITH ROLLERHEAD FABRIC WITH FOIL (0.25 OR 1.3) Tolerances smooth pressed Tolerances ground on one side* Material thickness [mm] Tolerances [mm] Material thickness Tolerances [mm] 0.75 … 2.0 ± 0.25 – – – – – – – – [mm] 1 … 2 – – – – ± 0.25 – – – – 0.75 … 2.0 ± 0.25 1 … 2 ± 0.25 – – – – – – 1 … 2 ± 0.25 MATERIAL NBR CR ACM VMQ FVMQ EPDM HNBR FKM Material thickness [mm] 0.5 … 2.0 0.5 … 2.0 0.5 … 2.0 – – 0.5 … 2.0 0.5 … 2.0 0.5 … 2.0 0.5 … 1.0 mm: ± 0.1 mm > 1.0 mm: ± 10 % 0.5 … 2.0 mm: ± 0.1 mm * Tighter tolerances up to ± 0.05 possible on request 678

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions SHEETING 500 mm WIDTH ROLLERHEAD ROLLERHEAD WITH FABRIC ROLLERHEAD WITH FOIL (0.25 OR 1.3) MATERIAL Material thickness [mm] Tolerances smooth pressed Tolerances ground on one side Material thickness [mm] Tolerances [mm] Material thickness Tolerances [mm] NBR CR ACM VMQ FVMQ EPDM HNBR FKM 0.5 … 4 0.5 … 3 0.5 … 2 – – 0.5 … 4 0.5 … 3 0.5 … 3 CIRCULAR BLANKS D 200 0.5 … 1.5 mm: ± 0.15 mm > 1.5 mm: ± 10 % 0.5 … 2.0 mm: ± 0.1 mm 0.75 … 2.5 ± 0.25 – – – – – – – – [mm] 1 … 3 – – – – ± 0.25 – – – – 0.75 … 2.5 ± 0.25 1 … 3 ± 0.25 – – – – – – 1 … 3 ± 0.25 CIRCULAR BLANKS THICKNESS (FROM 0.5 mm TO 6.0 mm) – INCREMENTS OF 0.1 Pure elastomer Circular blanks with fabric reinforcement or 0.5 … 6.0 mm PTFE foil 0.8 … 6.0 mm THICKNESS TOLERANCES OF THE PRESSED SHEETS (FOR MATERIAL UP TO A HARDNESS OF 75 SHORE A) MATERIAL WITHOUT FABRIC WITH FABRIC OR PTFE FOIL I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B NBR SBR CR VMQ FVMQ EPDM HNBR FKM ± 0.075 ± 0.10 ± 0.10 ± 0.15 S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 679 X E D N I Smooth-pressed sheets Tolerance adjustment necessary for material with hardness > 75 Shore A Larger sheet thickness incl. thickness tolerances on request

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Special Sealing Products SHEET DIMENSIONS, TYPE 300 X 300 mm SHEET THICKNESS (FROM 0.5 mm TO 6.0 mm) – INCREMENTS OF 0.1 mm Pure elastomer sheets Sheets with fabric reinforcement or PTFE foil 0.5 … 6.0 mm 0.8 … 6.0 mm THICKNESS TOLERANCES OF THE PRESSED SHEETS (FOR MATERIAL UP TO A HARDNESS OF 75 SHORE A) MATERIAL WITHOUT FABRIC WITH FABRIC OR PTFE FOIL NBR SBR CR VMQ FVMQ EPDM HNBR FKM ± 0.10 ± 0.15 ± 0.15 ± 0.20 Smooth-pressed sheets Tolerance adjustment necessary for material with hardness > 75 Shore A Thicker sheet thickness incl. thickness tolerances on request 680

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions SHEET DIMENSIONS, TYPE 500 X 500 mm SHEET THICKNESS (FROM 0.5 mm TO 6.0 mm) – INCREMENTS OF 0.1 mm Pure elastomer sheets Sheets with fabric reinforcement or PTFE foil 0.5 … 6.0 mm 0.8 … 6.0 mm I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H THICKNESS TOLERANCES OF THE PRESSED SHEETS (FOR MATERIAL UP TO A HARDNESS OF 75 SHORE A) MATERIAL WITHOUT FABRIC WITH FABRIC OR PTFE FOIL NBR SBR CR VMQ FVMQ EPDM HNBR FKM ± 0.15 ± 0.20 ± 0.20 ± 0.25 Smooth-pressed sheets Tolerance adjustment necessary for material with hardness > 75 Shore A Thicker sheet thickness incl. thickness tolerances on request PRECISION SHEETS (CUSTOMIZED TOOLS REQUIRED) SHEET SIZE 100 x 100 mm 120 x 120 mm 135 x 135 mm TOLERANCE ± 0.02 ± 0.04 ± 0.05 R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 681 X E D N I

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Special Sealing Products DELIVERY PROGRAM Production and dimensions of sheets Sheets are available in the following sizes: PRODUCTION OF SHEETING Continuous production is possible for y order quantities > 30 m y width up to 500 mm y thickness up to 3 mm PRODUCTION OF GROUND SHEETS AND SHEETING Tolerances of ± 0.05 mm can be achieved by grinding on one or both sides. For Shore hardnesses below 50 Shore A, however, grinding is only possible in individual cases. The surface quality of ground or sand- blasted sheets depends greatly on the shore hardness and base material. Sheets and sheeting are not available from stock. y Ø 200 (circular blank) y 100 x 100 (precision sheet) y 120 x 120 (precision sheet) y 135 x 135 (precision sheet) y 159 x 152 mm y 200 x 200 mm (Simriz®) y 300 x 300 mm y 350 x 350 mm y 500 x 500 mm (pressed) y 500 x 500 mm (from sheeting) Pure elastomer sheets Sheets with a fabric overlay Sheets with a fabric insert Sheets with foil made of PTFE THICKNESS * [mm] 0.5 … 6 0.8** … 6 1.2** … 6 0.8** … 6 * Minimum thickness, depending on the fabric or PTFE film thickness ** The maximum thickness varies depending on the material and sheet size 682

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions 2.12 PROFILES, CORDS AND HOSES PRODUCT BENEFITS PRODUCT OVERVIEW y profiles/profile rings • U-rings • mating rings for U-rings • hat seals • X-profiles • other special profiles y cords/cord rings y hoses/hose rings PRODUCT DESCRIPTION Special profiles, cords or hoses are used whenever large sealing contact areas cannot be effectively sealed by form seals or O-rings, for example, in tunnelling machines, ship engines and hatchways. Different profile nozzles and numerous materials are available for this purpose. Another core competency of Freudenberg Sealing Technologies is the development and production of customer-specific designs, where the tool costs are very low compared to molded parts. MATERIAL Besides the common materials, many special materials are also available. These are characterized by outstanding quality and durability. The “Ventoguard” series of compounds was developed for the wind power sector, for example. This offers excellent long-term relaxation behavior and is resistant to all common lubricants. y Sealing large seal contact areas that cannot be sealed by an O-ring or a shape-related component y Customer-specific product develop- ment y Low tool costs compared to shape- related components y Ring diameter flexibly adaptable y Vertically-integrated tool construc- tion to ensure short supply times y Extensive material portfolio y Vertically-integrated material devel- opment (e.g. for the development of application- specific materials) y Small quantities possible USES Components manufactured from profiles perform sealing tasks in numerous indus- trial sectors: y heavy-duty mechanical engineering, e.g. tunneling technology, cement/ rock mills y plant engineering, e.g. turbines, shut-off valves, process cylinders y prime movers, e.g. ship engines y separators, e.g. filtering technology, large separators y wind turbines, e.g. blade bearing seals or flange seals for offshore turbines I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 683 X E D N I

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Special Sealing Products DESIGN NOTES Tolerances All profiles, cords and hoses are manufac- tured according to DIN ISO 3302-1 E2. In exceptional cases, production according to E1 is also possible. Limits for dimensions of cross sections of extruded components not supported: NOMINAL DIMENSION [mm] TOLERANCE CLASS [mm] E1* 0.15 0.20 0.25 0.35 0.40 0.50 0.70 0.80 1.00 1.30 E2 0.25 0.35 0.40 0.50 0.70 0.80 1.00 1.30 1.60 2.00 from 0 1.5 2.5 4.0 6.3 10.0 16.0 25.0 40.0 63.0 to 1.5 2.5 4.0 6.3 10.0 16.0 25.0 40.0 63.0 100.0 * Sometimes possible in individual cases 684

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions U-RINGS X-PROFILES U-rings are used as piston or rod seals and can be manufactured in NBR or FKM with different dimensions for cross-sections and diameters. The inner diameter of the U-ring should be at least 15 times the profile cross-section dimension (T). MATING RINGS FOR U-RINGS Mating rings are used for fastening and prevent axial movement of the U-rings, which can damage the sealing edges at the sealing lips. The mating rings are always supplied by the meter. Assembly note During installation, the two ends are placed flush to one another. The mating rings can be seated on the U-rings with a slight axial tension. X-profiles are used for sealing rods, cylinders and housings. The lower compression force required as a result of the four-lip sealing profile makes them favorable to round profiles. In addition, X-profiles can easily be used in a rectangular groove thanks to their contour. The decisive advantage of the X-Profile is that the risk of tilting and twisting is minimized due to the larger bearing surface. OTHER SPECIAL PROFILES Profiles can be manufactured and sup- plied as follows: y by the meter with/without integral bend y profile sections produced to customer requirements y profile rings bonded to butt or batch vulcanized HAT SEALS Hat seals are used for sealing axially mov- ing rods. The hat seals are batch vulcan- ized in extruded form. All hat seals are equipped with tension springs. Note As a rule, these are customer-specific components that are adapted to your application by the experts using the FST design guidelines. For this reason, specific clarification of all rel- evant framework parameters is necessary. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 685 X E D N I

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Special Sealing Products For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). PROFILE NOZZLES Below is a selection of the 3,500 profile nozzles in stock. On request, individual tools are developed and manufactured for special designs. 30 14 12.5 12.5 3 1 21.8 18.3 15.5 10 25 15.5 35.8 11.5 16.2 16.2 12.5 12.5 32 12.9 19.5 11 17 10.5 0 5 5 1 6 12 9.5 9.5 10 17 8 10 8.5 4.5 18.5 12 14 16 13 686

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2 2 . 5 14 1 8 2 0 1 4 8 1 4 1 7 1 4 . 2 1 2 6 3 0 9 5 4 1 0 1 2 1 0 10 1 6 7 . 23 9 1 6 . 6 6 1 5 1 0 9 1 0 9.5 6 9 31 9 3 9 1 . . 9 5 6 8 7 1 8 . 3 1 0 1 5 . 5 2 5 17 2 0 1 0 8 . 5 5 0 2 0 3 8 4 3 5 2 3 7 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS 2 . E l a s t o m e r C o m p o s i t e P a r t s / P r e c i s i o n M o l d e d P a r t s / P T F E S e a l i l n g S o u t i o n s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Special Sealing Products 16.5 62 2 4 11 10 11 8.3 6.4 6.4 10 10.2 10 0 1 7 3 10 47 10 10 5 6 40 14 6 30 30 16 10.4 0 2 13 9 5.5 11 8 25 32.35 10 12 0 1 3.8 6 1 21.9 16 6 15 3 1 . 5 1 1 18 688

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1 8 1 6 67 15 . 4 5 7.5 6 . 5 17 5 . 8 7 5 2 2 3 . 8 6 8 9 23 9 1 . 6.7 1 8 6 8 2 6 . 6 1 0 13.3 67 1 1 5 . 3 1 0 1 0 3 . 1 5 1 2 1 1 1 5 1 . 67 1 8 . 7 7 1 7 68 1 5 1 3 . 2 4 0 ° 1 8 1 7 2 . 60 7 0 84 1 5 1 3 4 8 7 8 . 4 3 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS 2 . E l a s t o m e r C o m p o s i t e P a r t s / P r e c i s i o n M o l d e d P a r t s / P T F E S e a l i l n g S o u t i o n s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Special Sealing Products 6 . 4 4 86 13 44.6 . 5 1 1 4 8 16 16.6 9 1 45° 13 2 . 0 2 . 6 4 4 8 49 5 4.8 20 7 4 38 12.5 6.8 17.75 4 0 1 16 11 5 . 3 1 5 . 5 4 12 690 16.5 12 8 6 1 4 1 20 22 27 7 7.5 5 . 2 1 8.9

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2 5 10.13 5 5 . 5 3 68.6 5 5 . 4 2 4 3 9 2 5 13.2 2 3 1 0 31 6 9 1 4.7 1 0 7 5 3 9 ° 3 3 1 5 3 2 2 2 8 5 8 1 0 0 7 . 2 . 2 5 1 9 2 1 19.5 16 5 8 5 . 5 1 1 7.4 10.5 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING 9.7 6 . 6 9 1 5 5 . 5 14 3.8 2 . E l a s t o m e r C o m p o s i t e P a r t s / P r e c i s i o n M o l d e d P a r t s / P T F E S e a l i l n g S o u t i o n s INTRODUCTION & SERVICES

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Special Sealing Products CORDS AND CORD RINGS With a round cross-sectional shape, the round cord and its derivatives are the simplest sealing profiles and are often used as an alternative to large O-rings. However, as indicated in → “2.13 Profiles, cords and hoses – Design notes”, page 684, the manufacturing tolerances are greater, which must be taken into account when designing the groove dimensions. In addition, the O-ring standards are not applicable to the round cords and cord rings. Delivery program y by the meter: from 1 to 40 mm cord diameter y cord sections by the meter: pieces of cord cut to exact length y cord rings made by the meter: closed rings cut to the appropriate diameter and glued or vulcanized at the joint HOSES AND HOSE RINGS With a circular hollow area on the inside, hoses and their derivatives are also simple sealing profiles and are often used when lower compression forces are required and rather low demands are placed on a sealing. This type of hose is heated in an exposed position. The delivery program is compa- rable with the cords, although ovalization can occur during the heating process in unfavorable combinations of inside and outside diameters. Which combination of inner to outer diameter or wall thickness is still possible must be checked in each individual case. Delivery program y by the meter: depending on the wall thickness up to 40 mm outer diameter y hose sections by the meter: pieces of hose cut to exact length y hose rings made by the meter: closed rings cut to the appropriate diameter and glued or batch vulcanized HOSES HEATED ON MANDREL Precision hoses are manufactured from all common elastomer materials in a special process in successive process steps: First, the hoses are extruded, then drawn onto a mandrel with some pre-tension and “mandrel vulcanized.” Finally, the outer diameter is ground over. In this way, the inner and outer diameters can be pro- duced in finely tuned tolerance positions close to the molding tolerances. Due to the manufacturing process, the surface on the inner diameter is smooth pressed and the surface on the outer diameter has a very fine grinding structure. Under certain conditions, the process is also suited for producing particularly thin-walled hoses. 692

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions Delivery program Precision hoses “heated on mandrel” are always supplied in the following designs in coordination/on request. y hose pieces: up to 2,000 mm length without integral bend RINGS PIERCED BY THE HOSE In the production of rings pierced by the hose, short pieces of hose (discs) are usu- ally cut from the hose without cutting on a cutting device. Depending on the toler- ance requirements for the sealing ring, the hose can be manufactured either as a freely extruded hose or as a “hose heat- ed on mandrel and ground over on the outside.” Rings pierced by the hose have absolutely sharp edges on the inner and outer diam- eters, which is not possible in this way in the manufacture of molded sealing rings. The end faces of the rings show fine grooving due to the piercing process. Delivery program Hose rings are supplied from a wall thick- ness of 1 mm and up to an inside diameter of 200 mm, e.g. as sealing rings, drive belts, pressure rings or cleaning roll covers. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 693 X E D N I

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Special Sealing Products 2.13 MAGNETIC ANCHORS AND VALVE BODIES PRODUCT BENEFITS y Purchasing and logistics are simpli- fied – the spring can already be inte- grated into the design (e.g. meander spring design) y The magnet anchor with elastomer can be supplied as a unit instead of the individual components anchor, elastomer part and spring y The costs of the metal part are re- duced, as cross holes and undercuts can be omitted y The assembly of the anchor can be omitted y Smaller solenoid valves are possible because the elastomer can be in- jected into the smallest recesses and bonded to the carrier material y Optimized switching precision by achieving high accuracies in toler- ances and flatness, even without re- working steps A solenoid valve is an electromechanical control device used to regulate the flow of liquid or gaseous media. When current is applied to the solenoid valve coil, it gen- erates a magnetic field that moves the anchor inside the coil and thus regulates the flow of media. Solenoid valves can be used in a wide variety of applications, including air and flu- id pressure controls, heating and cooling systems, industrial or automotive appli- cations. Magnet anchors are high-precision seal- ing elements that can also be specially adapted to customer applications and critical requirements. Fig. 327 Meander springs Fig. 328 Tilt anchor 694

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions y superior design complex designs and miniaturization al- low the implementation of challenging solutions for customers y approvals various material approvals for elasto- mer materials, such as FD A conformity, KTW or USP Class VI for critical appli- cations are available y coatings PTFE, DLC or other coatings and treat- ments (e.g. plasma etching) to reduce friction on metal contact surfaces of the magnetic anchor are available. Coatings of the elastomer with PTFE or other types of materials are also possi- ble to optimize valve performance APPLICATION Typical automotive applications include: y engine: • injection systems • flush valves (e.g. ACF valve)/tank shut-off valves • AdBlue® systems (injection, pump, etc.) y E-Mobility/Hybrid: • battery vent valves • air Isolation valves (AIV) y spring/brake: • air supply of the pneumatic brake • air suspensions y comfort system: valves for massage seats, air condition- ing, convertible top (open/close), etc. TYPES Lifting anchor Within a guide mechanism, flexible lifting anchors combine the sealing and damp- ing function in a single component. In addition, the weight can be reduced by selecting individual carrier materials. Typical applications are pneumatic valves in the automotive sector, household ap- pliances and general industry. Tilt anchor Axially fixed anchors made of different carrier materials allow fast switching times and sustainable process optimiza- tion. Typical applications are pneumatic valves in the field of rice sorting plants, etc. Meander springs Magnetic anchors in the form of meander springs with sealing and damping functions allow minimal strokes at high frequencies in the smallest possible space. Typical applications are valves in various liquids or gases in all fields of application, such as engine injection, tools (nail guns), etc. DESIGN FEATURES y function integration sealing and damping functions can be combined in one component y materials customized sealing and damping ma- terials available, including for aggres- sive media and temperatures y surface treatments the adhesive effect can be reduced by means of RFN surface treatment I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 695 X E D N I

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Special Sealing Products y tools: gas injection, e.g. for nail guns APPLICATION-SPECIFIC ASSESSMENT Function estimation/application simulation y finite element method (FEM) of valve behavior • optimized load on the seal by im- proving the design in the run-up to the functional tests • simulation of the rebound for bet- ter design of the necessary forces (spring, magnet) • possible cost reduction through re- duction of test intervals (individual evaluation necessary) Typical industrial applications include: y energy: • solar panels • wind power plants/wind turbines y building services/household: water fittings with automatic confir- mation y pneumatic system: • switching valves/units • valve blocks y food and beverages: • bottling stations • rice sorting plants • coffee machines y heating/cooling systems: • oil burner injections • shut-off valves y medical applications/ miniaturized valves: • blood pressure monitors • anesthetic vaporizers • calibration devices • fans Fig. 329 FEM simulation 696

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions ELASTOMER MATERIALS ELASTOMER TYPICAL MEDIA TYPICAL TEMPERATURE RANGE NBR HNBR FKM/FPM EPDM FVMQ VMQ Oil; fuel; air Oil; fuel; air; AdBlue® Fuel; gas (CNG; LPG ...); exhaust gases; oil; air; H2 Air; water; AdBlue® Exhaust gases; H2 Air; water; H2 [°C] ‒60 … +80 ‒60 … +140 ‒40 … +220 ‒50 … +140 ‒70 … +220 ‒70 … +220 CARRIER PARTS MATERIALS MATERIAL TYPICAL MATERIALS ALTERNATIVE NAMES/ COMMENTS Stainless steel 1.4105; 1.4104; 1.4016; 1.4113 AISI 430 (F, FR); AISI 434 Steel Plastic Brass Aluminum Special 1.0338 AISI 1008 PA66; PPS; PBT Min. 30 % GF or GK CuZn38Pb2 AlMgSi Upon request I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 697 X E D N I

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Special Sealing Products MOUNTED ANCHOR VS. CHEMICAL BOND COMPARE ADVANTAGES DISADVANTAGES Surfaces y free from binder y surface finishing before assembly y no surface interruptions due to gat- ing (gating can be provided opposite sealing surface – taken into account during installation) Expensive metal (anchor) parts y undercuts necessary for assembly y cross holes necessary for venting during assembly Tolerances y parallelism of the sealing surface is Assembly of the final magnetic anchor y automation of assembly for small defined by the flatness and the spring below the elastomer part y total length of the part is independ- ent of the elastomer production pro- cess y swelling and thermal influences/ex- pansion have no influence on the application batches or medium quantities is often not economical y handling and orientation of the small elastomer parts often very difficult y many different parts to be handled y with increasing size reduction of the anchor, the assembly costs increase y risk of contamination increases y the burr can be sheared off the part during assembly and gets into the system Materials various elastomer materials can be com- bined with each other, as two individual parts are manufactured and assembled Surfaces y rubber ridge on the part y the burr can loosen over the service life and clog the valve High purchasing and logistics costs y many small parts y more than one supplier Tolerances depending on the design, sometimes only very rough tolerances can be main- tained Tolerances Functionality depending on the design, the elastomer part can fall off – caused by adhesive ef- fects or backflushing Mounted solution 698 Adhesive effectBackwash

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2. Elastomer Composite Parts/ Precision Molded Parts/ PTFE Sealing Solutions COMPARE Chemical bond ADVANTAGES DISADVANTAGES Cost of the metal (anchor) part is reduced cross holes and undercuts can be omit- ted Surfaces y binder overflow or rubber ridge on the carrier part surface possible y rework, such as overgrinding, critical y surface interrupted by gating No mounting of the final magnetic anchor Tolerances y parallelism and flatness dependent on the mold y swelling and thermal influences/ expansion have more influence on the application Materials different elastomer materials not always possible due to the manufacturing process Purchasing and logistics are simplified y instead of a metal part, an elastomer part and spring, a complete assembly can be supplied y additional springs within the anchor no longer necessary Smaller magnet valves possible the elastomer can be injected directly into the smallest openings and be bonded to the metal Elastomer composite parts enable optimized switching precision y vulcanization ensures a secure and clearly defined bond y highest standards with regard to tol- erances and flatness can be ensured even without reworking steps Tolerances y higher accuracies possible y better flatness of the sealing surface can be achieved by optimizing the tool design using the finite element method y various design variations possible, based on customer requirements I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 699 X E D N I

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Special Sealing Products 3. CUSTOMIZED INTEGRATED PRECISION SOLUTIONS WITH PLASTIC Freudenberg Sealing Technologies offers its customers customized and functionally optimized “Integrated Precision Seals.” These are multi-material composite parts for customer-specific applications with complex requirements. A carrier material, in this product group usually made of a thermoplastic, is bonded to an elastic material (elastomer or ther- moplastic elastomer) in order to implement additional functions, e.g. sealing, guiding, shielding (e.g. from electromagnetic radia- tion), conducting (e.g. of heat). PRODUCT BENEFITS y Easier assembly: Connecting structur- al parts (e.g. housings, covers, support elements) with bonded softmaterial components simplifies the assembly of subassemblies (e.g. the assembly of flexurally flexible seals!) y Weight reduction: Replacement of metal housings by plastic housings with integrated seals reduces the overall weight of assemblies y Design freedom: Plastic technology offers outstanding design freedom and makes complex structures possi- ble – both for carrier parts and for soft components y Firm connection: Decades of experi- ence in the bonding of elastic materi- als to the carrier plastics ensures high reliability, even in stressed loads – superior dynamic reliability y Functional reliability: A range of special sealing materials from Freudenberg Sealing Technologies is available in combination with thermoplastics – leading the way in sealing technology y Risk reduction: Firm connection of the carrier part and the functional mate- rial (e.g. seal) prevents faulty assem- bly; positional reliability is ensured by design. High level of automation en- sures high permanent process relia- bility and quality y Fewer parts: The bonding of materials reduces the number of items on the material list and in the supply chain y Process freedom: In particular, assem- bly injection molding (plastic parts movable relative to one another, from a single tool) or PIT technology (pipes) enable new process approaches 700

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3. Customized Integrated Precision Solutions with Plastic This technology combines modern plastics technology with another core competen- cy of FST: elastomer and sealing technol- ogy. A huge variety of customer-specific applications and products is available due to the materials and manufacturing tech- nologies used. The product group can be roughly described by the term “2K+” technology. The “+” stands for the additional integra- tion of further elements, e.g. sleeves, con- nectors or other components. Freudenberg Sealing Technologies uses simultaneous manufacturing processes which – combined with high automation and process reliability – ensure excellent product quality. This covers a product range from small to medium-sized geom- etries, e.g. in the weight range of 0.05 to 1,500 grams/part. MATERIALS Carrier component – Overview of the main plastic materials used (generic terms), others are possible. PA Polyamides are semi-crystalline, thermo- plastic polymers characterized by high strength, stiffness and toughness. They also have good chemical resistance and processability. Polyamides react to the moisture content of the environment with reversible water absorption or release. Resistance to lubricants and fuels at tem- peratures up to max. +120 °C (short-term up to +150 °C). Polyamides are often used as substitutes for metals. Products made of this material are used as engine com- ponents (e.g. intake systems, fuel lines, engine covers, oil pans) and for com- pressed air systems for chassis and brakes, for example (read more → chapter “Materials and process engineering – PA”, page 82). PPA Polyphtalamides are semi-crystalline and semi-aromatic thermoplastic polymers. Due to their partially aromatic structure, they exhibit high glass transition temper- atures and a high melting point, making them suitable for continuous use up to over +150 °C. Polyphthalamides exhibit higher chemical resistance, even to aggres- sive chemicals, than standard polyamides. They are media resistant to biodiesel fuel, brake fluid, synthetic engine oil, transmis- sion fluid, transformer oil, glycols, sulfu- ric acid, road salt, zinc chloride, calcium chloride. Parts made of the material are particularly well suited for use in the cool- ing circuit in the automotive industry (read more → chapter “Materials and pro- cess engineering – PPA”, page 86). PPE Polyphenylene ether is a high-temperature thermoplastic. It is mainly used as a blend with polystyrene, impact-resistant sty- rene-butadiene copolymer or polyamide. PPE blends are used for molded parts in the electronics, household and automo- tive sectors, where high heat resistance, dimensional stability and dimensional stability are required. The surface can be printed, hot stamped, painted or metallized. Welding is possible by means of hot sheet, friction or ultrasonic welding. PBT Polybutylene terephthalate belongs to the polyesters and has similar properties to semi-crystalline polyethylene tereph- thalate (PET). However, it is better suited for injection molding due to its favorable I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 701 X E D N I

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Special Sealing Products PPS Polyphenylene sulfide, a semi-crystalline plastic whose aromatic monomer units are bonded together via sulfur atoms, is char- acterized by high heat resistance, good chemical resistance and rigidity. This mate- rial is used in assembly injection molding, among other applications. Assembly in- jection molding is a multi-component technology used by Freudenberg Sealing Technologies. In this process, no adhesion is achieved between the components, but instead composite parts are pro- duced that are movable relative to one another. The combination of these plastics with soft components such as NBR, XNBR, FKM, AEM, EPDM, VMQ or LSR and the group of TPEs (thermoplastic elastomers) is the core competency of Freudenberg Sealing Technologies in the field of inte- grated precision sealing solutions. In this area, FST is able to bring the full breadth of our experience to bear. There are too many combinations to present here. In particular, the processing and bonding of the materials to each other is the core competency of the responsible division and of FST (read more → chapter “Materials and process engineering – PPS”, page 85). cooling and process behavior and is val- ued for its high strength and stiffness, its very high dimensional stability (signifi- cantly better than that of POM or PA) and its good friction and wear properties. Polybutylene terephthalate is used for housings in electrical engineering, as well as in vehicle construction. Due to its very low water absorption and good hot water resistance, this material is frequently used in the sanitary industry (fittings) (read more → chapter “Materials and process engineering – PBT”, page 84). POM Polyoxymethylenes (also known as poly- acetals) are high-molecular-weight ther- moplastics. The material is characterized by high strength, hardness and stiffness in a wide temperature range and retains its high toughness. It has high abrasion resistance, a low coefficient of friction, high heat resistance, good sliding properties, good electrical and dielectric properties, and low water absorption. The properties of POM allow it to be used for precision parts, in particular (read more → chapter “Materials and process engineering – POM”, page 80). PP Polypropylene is a thermoplastic, semi- crystalline and non-polar plastic produced by chain polymerization of propene. Poly- propylene is resistant to grease and almost all organic solvents at room temperature, except for strong oxidizing agents. The relatively low material costs and its chem- ical resistance mean that this material is often used in the field of e-mobility (read more → chapter “Materials and process engineering – PP”, page 78). 702

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3. Customized Integrated Precision Solutions with Plastic CIRCUIT PROTECT Insulation elements for low and extra- low voltage and battery modules y three-dimensional plastic carrier parts y elastic seals subject to dynamic and/or static loads y integrated functional parts (e.g. sockets, sensors, busbars) y electromagnetic radiation protection (EMI shielding) y thermal insulation or heat dissipation y battery applications (heat shield) Freudenberg Sealing Technologies is known for its consistently high-quality parts, ensured by process automation. The functional reliability of the connection between the carrier and soft component is one of its core competencies. The required investment in tooling makes it ideal for use in applications from medium to large series. Special tooling technologies can also be used to implement cost-effective solutions for smaller series. Applications for the product groups listed can be found in general industry (mechan- ical engineering, mobile machinery, energy technology, fluid technologies and build- ing engineering ...), in automotive tech- nology and in the field of new mobility. 3.1 AREAS OF APPLICATION/ USES The applications of the technical solutions are diverse and can be summarized in three product groups: COVER & SEAL Complex thermoplastic housing/carrier parts for sensitive assemblies y elastic seals subject to dynamic and/or static loads y integrated functional parts (e.g. sockets, sensors) y electromagnetic radiation protection (EMI shielding) y thermal insulation or heat dissipation y assembly of components FLUID CONNECT Thermoplastic composite parts for guiding, conducting and controlling fluids y integrated elastic seals subject to dy- namic and/or static loads y highly resilient chemical bond y material combination hard/soft com- ponent y flexible materials (pipes) – Quantix y integrated functional parts (e.g. sockets, sensors) y assembly injection molding (parts that move relative to each other, e.g. flaps) I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 703 X E D N I

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Special Sealing Products INFORMATION NEEDED TO RESPOND TO REQUESTS Due to the complexity of the components, the desired technical performance and the requirements for the parts, close technical coordination is recommended right from the start of the project phases. The aim is to Note As a rule, these are customer-specific components that are adapted to your application by our experts using the FST design guidelines. For this reason, specific clarification of all rel- evant framework parameters is necessary. y coordinate the product design in line with production requirements y ensure the features relevant to the For this purpose, please ask your contact person for the EIS-Sheets (Engineering Information Sheets). function of the machine y make the correct choice of materials and their pairing for the application in question y take the latest innovative ideas on product design into account 704

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3. Customized Integrated Precision Solutions with Plastic 3.2 APPLICATION EXAMPLE – FLUID CONNECT – PIPES PRODUCT DESCRIPTION The precision pipes manufactured by Freudenberg Sealing Technologies are multi-material composite parts for cus- tomer-specific applications. They are used as cooling water pipes or as feeders for oil dipsticks, for example. Applications can also be found in the food industry. A thermoplastic is injected in the three- dimensional, sometimes highly complex geometries required by the customer and converted into a tube in the mold using innovative manufacturing processes. During the manufacturing process, addi- tional elements can be incorporated into the tube design, e.g. sleeves (to support assembly) or tube end seals can be inte- grated into the components. To further optimize assembly processes at the cus- tomer’s site, Freudenberg Sealing Tech- nologies uses a specially developed plas- tic material that enables the pipes to be flexibly formed in a reversible manner for assembly purposes. PRODUCT BENEFITS y Easier assembly: Plastic pipes with attached seals facilitate the assem- bly of subassemblies – especially when using flexible pipes y Reduced weight: Replacement of metal pipes with plastic pipes with an integrated gasket y Design freedom: Plastics technology offers a high degree of design free- dom, making complex structures possible y Firm connection: Decades of experi- ence in the connection of elastic ma- terials to the carrier plastics provide a high level of reliability for the seals, even under demanding dynamic loads when connecting the pipes to the assemblies y Functional reliability: A range of special sealing materials from Freudenberg Sealing Technologies is available in combination with thermoplastics I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Fig. 330 Fluid Connect – Pipes S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 705 X E D N I

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Special Sealing Products 3.3 APPLICATION EXAMPLE – FLUID CONNECT – ASSEMBLY INJECTION MOLDING (MOVING SUBCOMPONENTS) PRODUCT DESCRIPTION In the case of customer-specific solutions with subcomponents that move relative to one another, the specific properties of various specially developed plastics are used in the manufacturing process. This makes it possible to produce the moving subcomponents (sometimes with addi- tional molded-on seals) in a single mold. These composite parts are used, among other purposes, to control media flow and offer the customer a large degree of freedom in solving complex functionality requirements. PRODUCT BENEFITS y Reduced weight: By replacing metals with plastics with integrated seals y Design freedom: Plastic technology allows the implementation of com- plex structures y Firm connection of elastic materials to the carrier plastics provides high reliability for the seals, even in stressed dynamic loads y Easier assembly due to the use of already movably connected compo- nents with an attached seal Fig. 331 Fluid Connect – assembly injection molding (moving subcomponents) 706

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3. Customized Integrated Precision Solutions with Plastic 3.4 APPLICATION EXAMPLE – CIRCUIT PROTECT – CARRIER INCLUDING THE SEAL AND AN ADDITIONAL FUNCTION PRODUCT DESCRIPTION The use of plastic as a carrier material is possible for housings as well as for other components. The seals needed – with a mechanical or chemical connection – are connected to the customer-specific design with the car- rier part in a complex geometry. In addi- tion, other components (e.g. sleeves, pins, sensors) can be integrated into the part. The manufacturing processes used ensure consistently high quality – even with mil- lions of reproductions. PRODUCT BENEFITS y Reduced weight: By replacing metals with synthetic materials with inte- grated seals y Design freedom: Plastic technology allows a high degree of freedom of design and enables complex struc- tures y Firm connection of elastic materials to the carrier plastics makes the seals highly reliable, even in stressed dynamic loads y Easier assembly due to the use of components with an attached seal y Integration of additional functions, e.g. integration of contact pins for testing correctly mounted compo- nents Fig. 332 Circuit Protect - carrier including the seal and an additional function I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 707 X E D N I

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H Y D R A U L I C A C C U M U L A T O R S 7 0 9 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS H y d r a u l i c A c c u m u l a t o r s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Hydraulic Accumulators TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. GENERAL 3. DEFINITIONS 4. TECHNICAL BASICS Calculation and design Isothermal changes of state Polytropic changes of state Isothermal charging with subsequent polytropic change of state Isochoric changes of state 4.1 4.2 4.3 4.4 4.5 Corrective factors 4.6 4.7 Pulsation Damping 4.8 Pressure surge damping 5. DESIGNS 5.1 5.2 5.3 5.4 5.5 Piston accumulator Bladder accumulator Diaphragm accumulator Other types of accumulators Accumulator accessories 712 714 715 716 716 716 717 717 718 719 719 720 722 722 724 726 728 728 FURTHER CRITERIA FOR THE SELECTION OF A HYDRAULIC ACCUMULATOR 729 6.1 729 6.2 729 729 6.3 Gas losses 6.4 Properties by Design 731 Permissible operating overpressure Selection of the gas filling pressure p0 APPLICATION TEMPERATURE AND ELASTOMER VARIANTS 7.1 7.2 7.3 Seals for Piston accumulators Elastomers for Bladder accumu lators Elastomers for Diaphragm accumulators 732 732 732 732 6. 7. 710

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8. CONNECTIONS FOR HYDRAULIC ACCUMULATORS 8.1 Fluid connections 8.2 Gas connections 9. OPERATING INSTRUCTIONS 10. LEGAL REQUIREMENTS AND REGULATIONS 10.1 Pressure vessels in general 10.2 Pressure vessels in the EU 10.3 Transport recommendations 10.4 Safety regulations 11. MAINTENANCE 11.1 Repair 11.2 Failure diagnosis 12. DISPOSAL Table of Contents 733 733 733 733 734 734 734 734 735 736 736 736 737 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 711 X E D N I

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Hydraulic Accumulators 1. PRODUCT OVERVIEW 712 PRODUCT GROUPDESIGN DESCRIPTIONMAIN APPLICATIONSHydraulic accumulatorsPiston accumulatorsWith different configurations and sizes up to 350 bar, Freudenberg Sealing Technol-ogies offers both catalogue series and customer-specific solutionsIndustrial and mobile hy-draulic systems; hydraulics on land and construction machinery; factory auto-mation and robotics; power generation applications; automotive applicationsBladder accumulatorsBladder accumulators are also suited for use at lower tem-peratures. With nominal vol-umes of up to 50 liters and maximum operating pres-sures of 350 bar, they offer a wide range of applicationsWind turbines; presses; aggregates; break-out protectionsDiaphragm accumulatorsDiaphragm accumulators vary and come in a wide variety of materials, seals and fittings. They allow great functional safety as well as strength and are used in sizes from 0.07 up to 3.5 liters and maximum op-erating pressure of 350 barIndustrial and mobile hydraulic systems; hydraulics on agricultural and construction machinery; factory automation and robotics; power generation applications; automotive applications

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1. Product Overview Further information on our product portfolio I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 713 X E D N I MATERIALMAX. TEMPERATURE RANGE [°C] *STANDARD CATALOG RANGEVariousVariousYesNBR; ECO; FKM; …VariousYesNBR; ECO; CIIR; …VariousYes

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Hydraulic Accumulators 2. GENERAL FST Website Hydraulic accumulators Hydraulic accumulators from Freudenberg Sealing Technologies (also referred to as FST in the following) are used to store pressure energy. A hydraulic accumulator contains a compressible medium (e.g. nitrogen) and an incompressible working medium (e.g. hydraulic oil). The com- pressibility of the gas is used to store energy. It acts in a similar way to a spring. This gas is usually kept separate from the incompressible fluid. The type of separation distinguishes the various types of hydraulic accumulators from each other. Product catalog The different designs can be categorized into three main groups: y piston accumulators y bladder accumulators y diaphragm accumulators 714 In the case of special requirements (e.g. chemical aggressiveness of incompressi- ble media), metal bellows can also be used as a separator between a gas and a liquid. Hydraulic accumulators are now an inte- gral part of modern hydraulic systems. They increase the energy efficiency of hy- draulic systems, and also serve to enhance the comfort of machines and systems. Their diverse applications include energy storage as well as the damping of pul sations. They are used for volume compensation in closed systems or weight compensation, to ensure emer- gency functions, chassis suspension or – increasingly – energy recovery (conver- sion of kinetic energy back into hydraulic energy).

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3. DEFINITIONS a) Operating (over)pressures Each in a hydraulic accumulator with liquid filling and in a hydraulic system prevailing pressure. p1 = minimum working pressure pm = medium operating pressure p2 = maximum working pressure p3 = p4 = max. permissible pressure in the hydraulic system (pressure setting, pressure limitation, p3 ≤ 0.9 x p4) permissible operating overpres- sure (PS). Max. pressure for which the hydraulic accumulator is designed and that is specified in the technical documentation and the marking (name plate, lettering) b) Gas filling pressure p0 Pressure in the gas chamber of the hydrau- lic accumulator when it does not contain a liquid charge. The gas filling pressure is generally introduced and specified at room temperature (T = +20 °C). c) Gas filling For hydraulic accumulators, nitrogen (class 4.0) is always and exclusively per- missible as the filling gas. The use of com- pressed air or oxygen is not permitted (risk of explosion). d) Permissible pressure ratio p2/p0 A value specified by the manufacturer relating to the diaphragm or bladder flex- ing movement and therefore, component service life. These values must not be exceeded (pressure values are given as absolute values), e.g. 8:1 in the case of diaphragm accumulators. The special pressure ratios that apply to the various types of accumulators can be found in the product data sheet. 3. Definitions e) Permissible pressure fluctuation range Δpzul Max. permissible pressure difference p2 – p1 for 2 million load cycles = technical fatigue strength of the pressure-bearing shell (fatigue strength on request). f) Permissible operating temperature (TS) Permissible minimum/maximum temper- ature (TS) for which the hydraulic accu- mulator is designed. It includes all com- ponents of the hydraulic accumulator, including sealing materials, e.g. bladder or membrane material. g) Operating medium Hydraulic accumulators can only be oper- ated with media for which they have been designed and approved. Particular atten- tion must be paid to the chemical resist- ance or corrosive properties of the various operating media on the components of hydraulic accumulators. h) Installation position Type-specific specifications must be ob- served. An additional installation space of 200 mm should be kept free above the gas valve for testing and filling devices. i) Mounting The hydraulic accumulator must be mounted in such a way that a secure hold is ensured in the event of operational vibrations or possible breakage of the connection cable and that no stresses act on the hydraulic accumulator. If applicable, type-specific special considerations must be observed. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 715 X E D N I

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Hydraulic Accumulators 4. TECHNICAL BASICS 4.1 CALCULATION AND DESIGN Nearly all formulas for the calculation of hydraulic accumulators are based on the change of state or gas equations for ideal gases. Although it is known that nitrogen, the most commonly used filling gas, ex- hibits real gas behavior at high pressures and/or low temperatures which can de- viate noticeably from the behavior of an ideal gas, the following formulas have proven to be useful in practice for initial approximate calculations for pressure ranges up to around 200 bar. In addition, other important influences, such as the viscosity of the liquid, length and width of pipelines or connections, valve closing times, moving masses, etc., are sometimes not known at all or at least not exactly known in terms of their effect on the entire circuit, and therefore more or less accurate assumptions must also be made. For the further analysis of a problem and its optimal solution, in addition to com- plex simulation calculations, tests are therefore still recommended today, which should be carried out at the operator’s site under practical conditions, as these are more realistic than conditions simulated in the laboratory. In general, it can be assumed that the calculation of static cases produces more accurate results than the calculation of dynamic processes. d f0 k l = clear width of a pipeline = natural frequency of a storage tank = pump factor = pipeline length n p p0 p0T p1 pm p2 pSt = polytropic exponent = pressure (as an absolute value) = gas filling pressure at room temperature = gas filling pressure at temper- ature T = minimum working pressure = medium operating pressure (with pulsation) = maximum working pressure = isothermally achieved station- ary pressure (p2/p0T)zul = permissible pressure ratio Δp Δpzul = pressure difference, variation = permissible pressure differ- Q T T1 T2 V0 V1 V2 VH VSt ΔV Z δ ε κ ρ ence p4 – p1 = flow current = absolute temperature in K = temperature at p1 ; V1 = temperature at p2 ; V2 = gas volume without liquid fill- ing = gas volume at p1 = gas volume at p2 = swept volume of a single piston of a piston pump = gas volume at pSt = volume of liquid stored be- tween two pressures = calculated table value = Residual pulsation (p2 – pm)/pm = pm/p0 = 1.4 (adiabatic exponent) = density of a fluid 4.2 ISOTHERMAL CHANGES OF STATE Isothermal changes of state reflect the state after very slow changes with full temperature compensation or after suf- ficiently long compensation time after another change. 716

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4. Technical basics I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A l V ∆ e m u o v d e r o t S ∆V l V ∆ e m u o v d e r o t S Isothermal Isothermal Polytropic Polytropic R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H ∆V R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P p0 p1 p2 p0 p1 Pressure p Fig. 333 Isothermal change of state Fig. 334 Polytropic change of state p2 Pressure p S L A E S C I T A T S The curves with the pressures on the abscissa and the stored volume on the or- dinate appear as straight lines in a double logarithmic system, but as curved right lines in a system with linear division. p · V = const. [1] p0 · V0 = p1 · V1 = p2 · V2 1 [2] ∆V = p0 · V0 · ( − ) – p2 1 – p1 4.3 POLYTROPIC CHANGES OF STATE In polytropic changes of state, heat ex- change with the environment is at least partially suppressed. Therefore, when the pressure in the gas increases, the temperature increases. Conversely, when there is a decrease in pressure, the temperature drops. If almost no temperature equalization takes place during rapid processes, one approaches adiabaticity, where the poly- tropic exponent n is replaced by the adi- abatic exponent κ = 1.4 (for nitrogen N 2 as a diatomic gas). For real gases, n can also become larger than 1.4. p · Vn = const. [3] p · Vn = p1 · Vn1 = p2 · Vn2 np0–p2 [4] ∆V = V0 · [( ) ‒ ( ) ] p0–p1 1 – n 1 – G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B 4.4 ISOTHERMAL CHARG- ING WITH SUBSEQUENT POLYTROPIC CHANGE OF STATE Frequent practical applications represent a mixture of isothermal and polytropic changes of state. After a slow isothermal S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 717 X E D N I

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Hydraulic Accumulators Polytropic Polytropic Polytropic ∆V ∆V ∆V Isothermal Isothermal Isothermal p0 p1 pSt p2 p0 p = pSt p0p2 p1 p2 = pSt Pressure p Fig. 335 Isothermal charging with subsequent polytropic change of state charge or starting from a stationary pres- sure, a polytropic change of state can occur, for example, in the case of a pressure surge or a sudden withdrawal of the stored pressure medium. In the calculation, the gas volume VSt is first determined isothermally at the station- ary pressure pSt and these two variables are then considered as initial variables in terms of V0 and p0 for the subsequent polytropic change of state (→ Fig. 335). Recommended: p0 = 0.6 x p1 bis 0.8 x p1 [5] p0–pSt VSt = V0 · npSt–p2 [6] ∆V = V0 · · [( ) − ( ) ] p0–pSt pSt–p1 1 – n 1 – 718 Special case: Polytropic charging on p2 starting from p1 = pSt np1–p2 [7] ∆V = V0 · · [1 − ( ) ] p0–p1 1 – Special case: Polytropic discharge on p1 starting from p2 = pSt ΔV becomes negative (withdrawal!). np2–p1 [8] ∆V = V0 · · [1 ‒ ( ) ] p0–p2 1 – 4.5 CORRECTIVE FACTORS At high pressures above 200 bar, gas equations based on ideal gases increasing- ly lose accuracy and it is recommended to use real gas equations or to apply correc- tion factors K according to equations 9 and 10. With K 1.2 > 1, the real selected storage volume must be larger than the calculated volume. The ΔV real to be used in for- mulas must be larger than the practical- ly required volume. Correction factors increase with increasing pressures and decrease with increasing pressure ratios p2 / p1 . [9] V0real = K1 · V0ideal [10] ΔVideal = K2 · ΔVreal

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4. Technical basics Map-marker-edit Calculate residual pulsation 4.6 ISOCHORIC CHANGES Some examples: OF STATE In an isochoric change of state, the gas volume remains constant and the pres- sure changes as a function of absolute temperature. For liquid-depleted hydraulic accumulators, this results in an increase or decrease in the gas filling pressure. For a closed system, the system pressure changes accordingly. Rule of thumb: a temperature change of 30 K or 30 °C results in a change in gas fill- ing pressure of about 10%, since 30 K is about 10% of RT = 293 K. [11] p – T = const. [12] p0T― T p0― = 293 p0T = p0 · T ― 293 293 K = room temperature RT 4.7 PULSATION DAMPING Pressure pulsations in hydraulic systems generally originate from pumps that de- liver unevenly, and piston pumps with only a few pistons in particular are known to generate pulsations. The non-uniformity of the transport results from the number and arrangement of the pistons and the resulting overlapping of the transport curves of the individual pistons. A key figure for this mode of action is the so- called pump factor k. k = 0.55 Single-acting single-piston pump k = 0.21 Double-acting single-piston pump or single-acting double- piston pump with 180° offset k = 0.423 Double-acting two-piston pump with 180° offset k = 0.009 Single-acting three-piston pump Hydraulic accumulators can be used to reduce pulsation to a residual pulsation d. Two calculation methods can be used to calculate this residual pulsation. Accord- ing to equation 15, p1 and p2 would have to be specified starting from the measur- able pressure pm. According to equation 16, the choice of the residual pulsation d and the pressure ratio pm/p0 would be sufficient. Since all other values are constants, equa- tion 16 can be transformed into equation 17 with a calculated value Z, which can be taken for some cases. Residual pulsation: p2‒pm―pm [13] δ = = pm‒p1―pm Pressure ratio: [14] ε = pm–p0 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 719 X E D N I

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Hydraulic Accumulators [15] [16] k · VH 1 – n V0 =― np0―p2 ( ) ( )p0―p1 − 1 – 1 k · VH · –npm―p0 ( ) V0 =― 1 ―1 1 –n ―1 − –n (1−δ) (1−δ) [17] V0 = VH · Z Please note that equations 16 and 17 can only be approximations, since they do not contain any frequency influence. As shown in the figure “Damping curve of a hydrau- lic accumulator with a single connection” (→ Fig. 336), the frequency plays an im- portant role in the damping behavior. In fact, hydraulic accumulators, unless they are special designs, develop their optimal damping behavior only in a narrow fre- quency band in the range of their natural frequency f0. dB i g n p m a D fD Frequency Fig. 336 Damping curve of a hydraulic accumulator with a single connection 720 Since not only the characteristics of a hydraulic accumulator itself, but also the cross-section and length of the connection line play a role in determining f0, it is rec- ommended that the manufacturer be consulted in cases of doubt. Natural frequency is increased by: y smaller nominal volume y higher gas filling pressure y larger connection cross section y smaller connection length Natural frequency is reduced by: y larger nominal volume y lower gas filling pressure y smaller connection cross section y larger connection length 4.8 PRESSURE SURGE DAMPING The most common cause of pressure surges in hydraulic systems is fast switch- ing valves. The calculation is based on the simplifying assumption that the entire energy of the flowing fluid within the hydraulic accumulator is converted into gas work by a pressure increase. Starting from the pressure p1 before the pressure surge, the pressure increase should not exceed a specified value p2 . Valve closing times are not taken into account in the calculation, nor are connec- tion resistances. The calculated value for the nominal volume of the hydraulic accumulator in question should therefore be taken as an initial guide value. It is recommended that tests be carried out.

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4. Technical basics I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I SINGLE PISTON PUMP – TWO-PISTON PUMP – THREE-PISTON PUMP – SINGLE SINGLE SINGLE R O F S L A E S Y R A T O R S N O T A C I I L P P A δ in % ε = 1.25 ε = 1.5 ε = 1.25 ε = 1.5 ε = 1.25 ε = 1.5 1.0 2.0 3.0 4.0 5.0 6.0 8.0 10.0 46 23 15 12 9 8 6 5 52 26 18 13 11 9 7 6 18 9 6 4 4 3 3 2 20 10 7 5 4 4 3 2 1.0 0.4 0.3 0.2 0.2 0.2 0.1 0.1 1.0 0.5 0.3 0.3 0.2 0.2 0.1 0.1 The recommended installation location is as close as possible to the origin of the pressure surge. The pressure surge should enter the hydraulic accumulator in as straight a line as possible without many deflections. [18] p0 = 0.8 · p1 With these values and dimensions ρ = 890 kg/m l in m Q in l/min p1 and p2 in bar n = 1.4 d in mm V0 in l the following tailored equation results: [19] V0 = 2 · ρ · 1 · Q2 · (n−1) n−1 · d2 · 0.8 · p1 · [( ) − 1] ―np2–p1 [20] V0 = 7.87 · 10-4 · l · Q2 0.2857 d2 · p1 · [( ) − 1] p2–p1 R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 721 X E D N I

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Hydraulic Accumulators 5. DESIGNS In modern hydraulic systems, hydraulic accumulators can be found in many appli- cations and for many functions. Hydraulic accumulators are distinguished from each other based on many aspects, for example: y the mode of operation (spring accu- mulator or gas-filled) y the type of assembly (screwed or welded) y the type of use (automotive or indus- trial application) y etc. In practice, the different designs are usu- ally categorized into three main groups: y piston accumulator y bladder accumulator y diaphragm accumulator 5.1 PISTON ACCUMULATOR In piston accumulators, a piston separates the liquid chamber from the gas chamber. The piston is free to move. If liquid is now forced into the hydraulic accumulator as 722 the hydraulic pressure rises, the piston moves and compresses the gas in the gas chamber. When the hydraulic pressure drops, the gas expands again, pushing the piston back to its original position and forcing the liquid out of the hydraulic ac- cumulator and into the hydraulic system. Depending on their size, piston accumu- lators are used in mobile equipment such as excavators, wheel loaders and other construction machinery, for example. They can also be found in stationary hydraulic systems, such as wind turbines or large presses, as well as in shipbuilding or in oil and gas industry plants Particularly in storage systems with very large effective gas volumes, part of the required volume can be added down- stream of the piston accumulator in the form of pure nitrogen accumulators. Piston accumulators offer the possibility of taking into account special require- ments for the connections on the gas or oil side. Here, threaded connections can be realized as well as flange connections or connections for temperature and pres- sure sensors. In addition, the piston posi- tion can be monitored and displayed using a wide variety of methods. Both mechanical and non-contact systems are used to optimally monitor operating conditions. DESIGN AND FUNCTIONALITY The pressure body of the piston accumu- lator usually consists of the tube as well as the caps installed on the gas and oil sides. For the sealing systems of the piston accumulators, Freudenberg Sealing Tech- nologies was able to apply its decades of experience as a leading seal manufacturer

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5. Designs ∆V p0 V0 p1 V1 p2 V2 Gas ﬁlling valve Gas side cap (Part of the pressure body) Cylindrical tube (Part of the pressure body) Piston with a sealing system Liquid side cap (Part of the pressure body) Fig. 337 Design of a piston accumulator Fig. 338 How a piston accumulator functions A B C and uses optimized sealing systems tailored to the respective application. The operating medium, the piston speed, as well as the materials of the pressure bodies themselves and the properties of the inner surfaces are matched to each other. Functionality (→ Fig. 338): A: The gas chamber is prefilled with nitro- gen, i.e. the piston is in contact with the liquid-side cap, there is no liquid in the piston accumulator. B: Piston position at minimum working pressure. A small amount of liquid be- tween the piston and the liquid-side cap prevents the piston from touching the cap within the working cycle. p0 must therefore be smaller than p1. C: Piston position at maximum working pressure. The volume change ΔV between minimum and maximum working pressure corresponds to the stored usable liquid volume. Limits of the gas filling pressure Compared to bladder and diaphragm accumulators, for example, much more extreme pressure ratios p2 : p0 can be realized with piston accumulators (theo- retically, p0 = 0 bar can be realized). For the level of gas preload, p0 = p1 – 5 bar usually applies (deviations due to temper- ature are possible). INSTALLATION POSITION A piston accumulator can operate in any position, but the vertical arrangement – gas side up or liquid side down – is prefer- able to avoid settling of dirt particles from the liquid onto the running surface of the piston or the piston seals. Vertical installation is required when using certain piston position indicators. An in- stallation space of 200 mm should be kept free above the gas valve for the test and filling device. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 723 X E D N I

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Hydraulic Accumulators MOUNTING The piston accumulator must be mount- ed in such a way that a secure hold is ensured in the event of operational vibra- tions or possible breakage of the connec- tion line and that no stresses act on the hydraulic accumulator. A wide variety of fastening concepts can be used, for ex- ample. 5.2 BLADDER ACCUMULATOR Map-marker-edit Reaction to the smallest changes in pressure In bladder accumulators, the liquid cham- ber is separated from the gas chamber by a bladder filled with gas (nitrogen). If liquid is now forced into the hydraulic accumu- lator as the hydraulic pressure rises, the bladder is compressed and the gas is compressed accordingly. When the hy- draulic pressure drops, the gas relaxes again, expanding the bladder and forcing the liquid back through the liquid valve into the hydraulic system. 724 Bladder accumulators are usually found in stationary hydraulic applications, such as wind turbines or powerful hydraulic power units, as well as in shipbuilding or in plants in the oil and gas industry. In spe- cial cases, however, they are also used in mobile equipment such as construction machinery or municipal vehicles. Since an accumulator bladder has no static friction during the operating cycle, bladder accumulators, unlike piston accu- mulators, react to even the smallest changes in pressure (< 0.1 bar). DESIGN AND FUNCTIONALITY A bladder accumulator essentially consists of a pressure body, usually made of a seamless tube, a fluid valve and a bladder with a gas valve. The liquid valve has only a protective function. It prevents the bladder from getting to the outside and being damaged. Furthermore, the liquid valve represents the connection of the accumulator to the hydraulic system. Different materials (including correspond- ing coatings) are available on request for both the pressure vessel as well as the liq- uid valve; these allow for adaptation to the operating temperatures or possibly corrosive properties of the operating me- dium. The bladder itself is made of a spe- cial elastomer material and can be adapt- ed to the operating conditions (temperature range, media compatibility) by selecting the appropriate elastomer. Functionality (→ Fig. 340): A: The bladder is prefilled with nitrogen, i.e. it is completely in contact with the inside of the accumulator shell, there is no liquid in the accumulator – liquid valve “closed”.

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5. Designs ∆V p0 V0 p1 V1 p2 V2 Gas ﬁlling valve Accumulator shell Bladder Fluid port incl. AER Fig. 339 Design of a bladder accumulator Fig. 340 How a bladder accumulator functions A B C V0 = V1 = V2 = ΔV = p0 = gas volume without liquid charge gas volume at p1 gas volume at p2 useful volume delivered or taken up between p1/p2 gas filling pressure at room temperature p1 = minimum working pressure p2 = maximum working pressure Limits of the gas filling pressure p0 ≤ 0.9 · p1; whereby the following per- missible pressure ratio must be observed: p2 : p0 ≤ 4 : 1 B: Bladder at minimum working pressure. A small amount of liquid between the bladder and the fluid port prevents con- tact between the bladder and the valve disc. Thus, p0 must be less than p1. C: Bladder at maximum working pressure. The volume change ΔV between mini- mum and maximum working pressure corresponds to the stored usable liquid volume. The bladder is filled with nitrogen via the gas filling valve. The bladder lies complete- ly against the inside of the accumulator shell (A). If liquid is now forced into the hydraulic accumulator as the hydraulic pressure rises, the bladder and accordingly the gas are compressed. Thus, the gas volume decreases with a simultaneous increase in pressure and thus stores the pressure energy (C). As soon as the pressure on the liquid side drops, this process is reversed and liquid is flushed back into the hydraulic system (B). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 725 X E D N I

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Hydraulic Accumulators INSTALLATION POSITION Bladder accumulators can operate verti- cally, horizontally and also in an inclined position, whereby the vertical arrange- ment – gas side at the top or liquid con- nection at the bottom – is always prefer- able in order to avoid significant restrictions in useful volume or flow rates. If the installation deviates from the vertical position, the manufacturer must be consulted beforehand. An installation space of 200 mm should be kept free for the test and filling device above the gas valve. MOUNTING Bladder accumulators must be mounted in such a way that in the event of operational vibrations or possible breakage of the con- necting line, a secure hold is ensured and no stresses act on the bladder accumulator. 5.3 DIAPHRAGM ACCUMULATOR In diaphragm accumulators, the liquid space is separated from the gas space by a diaphragm. Both the gas (nitrogen) and the operating liquid are in contact with the inner wall of the vessel. If liquid is now forced into the hydraulic accumulator as the hydraulic pressure rises, the diaphragm is deformed into the gas space, thus compressing the gas ac- cordingly. If the hydraulic pressure drops, the gas relaxes again, the diaphragm moves back towards the fluid chamber and thus forc- es the fluid through the fluid connection into the hydraulic system. Diaphragm accumulators are widely used in mobile hydraulic applications such as excavators, wheel loaders and other con- struction machinery, as well as in a wide range of agricultural applications (tractors, plows, sprayers, etc.). They can also be found on machine tools as well as in ship- building or in equipment for the oil and gas industry. Since a diaphragm requires no static fric- tion and only very low deformation ener- gy during the operating cycle, diaphragm accumulators respond to even the small- est changes in pressure (< 0.1 bar). DESIGN AND FUNCTIONALITY A diaphragm accumulator essentially consists of a pressure body, usually made up of two housing parts joined by EB welding, connections on the gas and liq- uid sides, and a diaphragm which is fixed in the housing by means of a clamping ring. The diaphragm itself is protected from damage at the oil-side housing opening by means of a diaphragm button. It prevents the diaphragm from leaking out under gas-side pressure without hydraulic counterpressure. Map-Marker-Exclamation Installation space for testing and filling device Map-marker-edit Reaction to the smallest changes in pressure 726

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5. Designs ∆V p0 V0 p1 V1 p2 V2 Gas ﬁlling valve Top cover EB seam Clamping ring Sub cover Diaphragm with protection button Liquid connection Fig. 341 Design of a diaphragm accumulator Fig. 342 How a diaphragm accumulator functions A B C The diaphragm is made of an elastomer material and can be adapted to the oper- ating conditions (temperature range, media compatibility) by selecting the appropriate elastomer. Functionality (→ Fig. 342): A: The gas chamber is prefilled with nitro- gen, i.e. the diaphragm is completely in contact with the inside of the accumulator body, there is no liquid in the accumulator: the diaphragm button closes the body opening. B: Diaphragm at minimum working pres- sure. A small amount of liquid between the diaphragm and the housing opening prevents contact between the diaphragm and the housing opening. Thus, p0 must be less than p1. C: Diaphragm at maximum working pres- sure. The volume change ΔV between minimum and maximum working pres- sure corresponds to the stored usable liquid volume. The gas chamber of the diaphragm accu- mulator is filled with nitrogen via the gas filling valve. The diaphragm lies com- pletely against the inside of the housing (A). If liquid is now forced into the hydrau- lic accumulator as the hydraulic pressure increases, the diaphragm is deformed into the gas chamber and the gas is com- pressed accordingly. The gas volume thus decreases while the pressure increases, thus storing the pressure energy (C). As soon as the pressure on the liquid side drops, this process is reversed and liquid is flushed back into the hydraulic system (B). V0 = V1 = V2 = ΔV = p0 = gas volume without liquid filling gas volume at p1 gas volume at p2 useful volume released or absorbed between p1/p2 gas filling pressure at room temperature p1 = minimum working pressure p2 = maximum working pressure I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 727 X E D N I

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Hydraulic Accumulators Limits of the gas filling pressure p0 ≤ 0.9 · p1; whereby the permissible pressure ratio of the individual accumu- lator sizes must be observed. INSTALLATION POSITION A diaphragm accumulator can operate in any position, although the vertical ar- rangement – gas side up or liquid connec- tion down – is preferable. An installation space of 200 mm should be kept free above the gas valve for the testing and filling device. MOUNTING The diaphragm accumulator must be mounted in such a way that in the event of operational vibrations or possible breakage of the connecting line, a secure hold is ensured and no stresses act on the diaphragm accumulator. 5.4 OTHER TYPES OF ACCUMULATORS In addition to the aforementioned types of accumulators, there are accumulators specially developed for an application that should be mentioned here for the sake of completeness. However, since these are customer-specific solutions (customer protection), they are not discussed in more detail. Among other things, there are accumula- tors in whose development weight plays a special role. Here, the various accumulators are available in lightweight design, in which aluminum or composite materials are used to manufacture the housings, for example. Another type of hydraulic accumulator is a special piston accumulator for automo- tive applications. Here, customer-specific connections are required that are tailored to the respective application. No list can be provided here. If necessary, please contact your FST representative. 5.5 ACCUMULATOR ACCESSORIES The equipment required for the safe op- eration of hydraulic accumulators is grouped under the heading of accumula- tor accessories. They range from filling and testing devic- es to safety and shut-off blocks and a va- riety of fastenings. It should be noted that only the functions are prescribed for the operation of accumulator systems, but the design is completely free. The selection of accumulator accessories from Freuden- berg Sealing Technologies is therefore only one way of planning and building in com- pliance with the regulations. 728

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6. Further criteria for the selection of a hydraulic accumulator 6. FURTHER CRITERIA FOR THE SELECTION OF A HYDRAULIC ACCUMULATOR 6.1 PERMISSIBLE OPERATING OVERPRESSURE The hydraulic accumulator must be select- ed so that the permissible operating over- pressure p4 is always above the expected upper operating pressure p2 and also above any pressure peaks that may occur. Pressure peaks or pressure increases occur, for example, due to switching of direction- al control valves and the resulting braking of oil masses, braking of fast-moving masses, pressure intensification in differ- ential circuits, etc. It should be noted in this connection that pressure peaks can occur for such short periods that they often cannot be meas- ured at all with the aid of damped meas- uring instruments (e.g. pressure gauges). Safety valves also do not always respond to such short-term pressure peaks. 6.2 SELECTION OF THE GAS FILLING PRESSURE p0 The level of gas filling pressure depends on the expected operating pressures and the type of application. The following values can serve as a guide: y with pulsation damping p0 = 0.6 to 0.8 x pm (pm = mean operating pressure) y for pressure surge damping or volume storage p0 = 0.6 to 0.9 x p1 (p1 = lower working pressure) It must be ensured that the gas filling pressure does not exceed the value of 0.9 x p1 even at operating temperature. The gas filling pressure introduced and specified at room temperature increases with rising temperature in accordance with the gas laws. As a rule of thumb, a pressure increase of 10% at a tempera- ture rise of 30 °C can be assumed. A gas filling pressure that is selected too low leads to higher filling levels in the hydraulic accumulator and thus to an unnecessarily high flexing stress on the diaphragm or bladder, which can lead to a reduction in the diaphragm service life. 6.3 GAS LOSSES Excessively low gas filling pressures can also be caused by gas losses due to per- meation processes. Since elastic partition materials are not leakproof in the abso- lute sense, filling gas molecules pass through the partition, are dissolved in the operating liquid and transported by it to the reservoir, where they can separate from the liquid again. Gas losses increase proportionally with operating pressure and exponentially with temperature. All other things being equal, gas losses in smaller hydraulic accumulators result in a more rapid drop in gas filling pressure than in larger hydraulic accumulators. Estimates of possible gas losses or drops in gas filling pressure can be made by the manufacturer if the operating pressure and operating temperature are known precisely. This, in turn, can be used to es- timate maintenance periods. A gas filling pressure that is too low from the start is further reduced by gas losses. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 729 X E D N I

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Hydraulic Accumulators e r u s s e r P p4 pOT 0 During filling: significant slowdown of the pressure rise When emptying: sudden drop in pressure to zero Fig. 343 Checking the gas filling pressure on the liquid side Stored volume A hydraulic accumulator is then unable to store the same volume of liquid under otherwise identical operating conditions. Membranes or bladders are overstressed as separators, shortening their service lives. The damping capacity of the hydraulic ac- cumulator is reduced and pressure peaks that occur can exceed the permissible operating overpressure. For this reason, the level of the gas filling pressure must be checked and, if necessary, supplemented at intervals appropriate to the particular application. The check can be carried out very easily with the aid of a DF filling device via the gas connection or by pressurizing from the liquid side. If only the level of the gas filling pressure is to be determined on the liquid side, this can also be done, provided there is a possibility of slowly filling or emptying the hydraulic accumulator. When filling slowly, one will notice a signif- icant slowing down of the filling process when the gas filling pressure is reached. When emptying, after a slowing of the pressure drop, there is a sudden drop in pressure to zero, which can be clearly ob- served on a pressure gauge. If necessary, this procedure can be carried out within a system without removing the storage tank. If the effective storage tank temperature deviates from the room temperature RT during the test, the result must be con- verted to RT = 20 °C. The use of filling devices in the installed state naturally requires, in addition to complete draining on the liquid side, good accessibility to the gas connections and sufficient headroom above them. Map-marker-edit Use filling devices 730

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6. Further criteria for the selection of a hydraulic accumulator 6.4 PROPERTIES BY DESIGN PISTON ACCUMULATOR Adaptation to installation space Possible (different diameters possible) BLADDER ACCUMULATOR Fixed volumes (size increments) DIAPHRAGM ACCUMULATOR Fixed volumes (size increments) Installation position Any (vertical depending on monitoring device) Vertical (horizontally restricted) Any (size-dependent restrictions possible) Permissible pressure ratio Any Max. 1:4 Max. 1:8 (size-dependent restrictions possible) Gas loss (permeation) Very low Medium Low to medium Monitoring of the filling degree or level Possible Not possible Not possible Dirt sensitivity Failure mode High Slow High frequency cycles Less suited Low Fast Good Low Medium Good I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 731 X E D N I

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Hydraulic Accumulators 7. APPLICATION TEMPERATURE AND ELASTOMER VARIANTS In the case of the abovementioned accu- mulator types, different elastomers are available to optimize compatibility for different media. Adaptation to different hydraulic fluids is often accompanied by adaptation to temperature windows. For example, an accumulator with elastomer parts made of NBR can be used in a different temper- ature window than an accumulator with elastomer parts made of ECO. 7.1 SEALS FOR PISTON ACCUMULATORS In the sealing systems for piston accumu- lators, Freudenberg Sealing Technologies can apply its decades of experience as a leading seal manufacturer and uses op- timized sealing systems tailored to the specific application. The operating medi- um, the piston speed, and also the mate- rials of the pressure bodies themselves and the properties of the inner surfaces are all matched to each other. Since the piston accumulator can be re- paired and thus all parts can be replaced individually, it should be noted that not all possible combinations are covered by the accumulator approval. 7.2 ELASTOMERS FOR BLADDER ACCUMU LATORS Bladder accumulators can be equipped with elastomer parts made of a wide va- riety of materials. In this way, the bladder accumulators can be adapted to a wide variety of applications. Here, too, the op- erating temperature range of the bladders must be taken into account. If necessary, the material of the housing and also the liquid connection as well as the gas connection must also be adapted to the operating conditions. Since the bladder accumulator can be re- paired and thus all parts can be replaced individually, it should be noted that not all possible combinations are covered by the accumulator approval. 7.3 ELASTOMERS FOR DIAPHRAGM ACCUMULATORS Diaphragm accumulators can be equipped with diaphragms made of a wide variety of materials. In this way, diaphragm accu- mulators can be adapted to a wide variety of applications. Here, too, the operating temperature range of the diaphragms must be taken into account. If necessary, the material of the housing and also of the liquid connection and the gas connection must also be adapted to the operating conditions. Some designs of diaphragm accumulators are repairable. In these designs, all parts can be replaced individually. It should be noted that not all possible combinations are covered by the approval of the accu- mulator. For the above-mentioned types of storage tanks, it should be noted: The tempera- ture window for which an accumulator is approved is the smallest common tem- perature window of all components (housing, cover and/or connections if ap- plicable, and all elastomer parts). Map-Marker-Exclamation Temperature window for accumulators 732

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8. Connections for hydraulic accumulators 8. CONNECTIONS FOR HYDRAULIC ACCUMULATORS Hydraulic accumulators require at least one, but in most cases two connections – a gas connection and a liquid connection. 8.1 FLUID CONNECTIONS All accumulators have at least one liquid connection. It is used to install the accu- mulator into the hydraulic system. Piston accumulators (less frequently diaphragm and bladder accumulators) may have more than one fluid connection. 8.2 GAS CONNECTIONS In the case of gas connections, a distinc- tion is made between connections for fur- ther piping (mostly in the case of piston and possibly bladder accumulators) and “real” gas connections with a valve func- tion. These connec-tions are used to fill the accumulators with gas (nitrogen) and can be of different designs. Again, it should be noted that not all possi- ble combinations are practical or possible. 9. OPERATING INSTRUCTIONS The operating instructions (enclosed with the delivery of goods – special agreements possible) provide further information on the use of hydraulic accu- mulators and thus regulate safe operation of the accumulators. These operating instructions must be followed. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 733 X E D N I

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Hydraulic Accumulators 10. LEGAL REQUIREMENTS AND REGULATIONS According to the directive, hydraulic ac- cumulators with a nominal volume great- er than 1 liter must undergo a conformity assessment procedure and be CE marked. Accumulators with a nominal volume of up to 1 liter and a maximum permissible pressure (PS) of up to 1,000 bar must not be CE marked. The testing of equipment and installation as well as safety during operation and re- peat tests are regulated by national law. The safety-related equipment parts are described in AD 2000, ISO 4126 and EN 14359. The repeat inspection intervals for an operation in Germany are specified in the Ordinance on Industrial Safety and Health (BetrSichV). 10.3 TRANSPORT RECOMMENDATIONS Hydraulic accumulators without gas pre-charging are generally not dangerous goods when empty. For accumulators with gas pre-charging, corresponding in- ternationally applicable dangerous goods regulations apply for each mode of trans- port, which must always be observed by every consignor: y for road and rail, special regulation 594 applies. Accordingly, the accumulators are not to be declared as dangerous goods y for all other modes of transport, such as air transport, inland waterway transport or maritime transport, hy- draulic accumulators prefilled with gas are to be classified as dangerous goods. The current regulations must be observed. Freudenberg Sealing Technologies recommends classifying such accumulators under UN 3164 2.2 Hydraulic accumulators are pressure vessels or pressure equipment whose manufacture and operation are subject to legal regulations. In any case, the provisions and regulations applicable at the place of use must be observed. 10.1 PRESSURE VESSELS IN GENERAL For pressure vessels or pressure equipment installed outside the Member States of the EU, the relevant national rules and regu- lations of the country of installation must be observed. Depending on the regulations, different material requirements may also have to be observed. 10.2 PRESSURE VESSELS IN THE EU The Pressure Equipment Directive, cur- rently 2014/68/EU, applies in the Europe- an Union. This directive defines the design, manufacture, conformity assessment and placing on the market of pressure equipment and assemblies with a maxi- mum permissible pressure of more than 0.5 bar. 734

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10. Legal requirements and regulations 10.4 SAFETY REGULATIONS Hydraulic accumulators are pressure ves- sels or pressure equipment. Their manu- facture and operation are subject to legal regulations. In any case, the provisions and regulations applicable at the place of use must be complied with. In addition, further regulations may apply to the operation of hydraulic accumula- tors in the various countries, compliance with which constitutes national law and must be observed. The basic safety regulations can be found in the operating instructions. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 735 X E D N I

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11.1. REPAIR Hydraulic accumulators can be repaired in some cases. Please be sure to observe the correspond- ing repair instructions for the various series. 11.2. FAILURE DIAGNOSIS Freudenberg hydraulic accumulators are designed for trouble-free operation. Should a failure nevertheless occur, pos- sibilities for failure diagnosis/damage analysis are available on the basis of years of experience. Please contact your FST representative if necessary. Hydraulic Accumulators 11. MAINTENANCE Hydraulic accumulators from Freuden- berg Sealing Technologies are largely maintenance-free after commissioning. To avoid operational malfunctions and to ensure a long service life, the following maintenance work must be carried out at regular intervals: y check gas filling pressure and refill if necessary y visual inspection for external corrosion y check line connection and fittings for leaks y check safety device for condition and function Before opening the gas connection, it must be ensured that the system or hy- draulic accumulator is depressurized. Fur- ther work on the hydraulic accumulators may only be carried out by authorized persons. For the above measures on the diaphragm accumulator, Freudenberg Sealing Tech- nologies recommends the following in- spection intervals: y initial test after (re)commissioning: after one week y second test after the initial test with- out complaint: after 2–3 months y regular test after the second test without detectable gas loss: annually Irrespective of the requirements of this document, periodic inspections must be carried out in accordance with national- ly applicable regulations. Map-Marker-Exclamation Follow repair instructions Map-Marker-Exclamation Inspection intervals to be observed 736

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12. DISPOSAL 12. Disposal As closed hollow bodies, hydraulic accu- mulators may not be placed unopened in scrap destined for melting in accordance with BGV D23. It is therefore necessary to depressurize and open hydraulic accu- mulators by carefully unscrewing the gas filling screws or gas filling valves. Filling devices are also ideally suited for this pur- pose. If necessary, subsequent disman- tling of the accumulator can enable the materials to be separated by type. In the case of special designs with a perma- nently closed gas filling opening (one-way accumulator), this can only be accom- plished by careful drilling (Ø ≥ 6 mm) of the gas chamber in a suitable holding device. Since the escaping gas can carry small metal splinters or particles, protec- tive goggles must be worn during this process. Extreme care must be taken when drilling out hydraulic accumulators, as the escaping gas can cause impulse noise. It is recommended that hearing protection be worn. Furthermore, when drilling out the hy- draulic accumulator, it must be noted that it contains nitrogen and thus displaces oxygen. For this reason, sufficient venti- lation must be ensured. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 737 X E D N I

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Hydraulic Accumulators 738

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B O O T S & B E L L O W S 7 3 9 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING INTRODUCTION & SERVICES

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Bellows TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. BELLOWS IN GENERAL 2.1 Functions 2.2 Application range 3. PRODUCT DIVERSITY 3.1 Standard bellows 3.2 Customized single- and multiple-convolution bellows 4. BASIC PRINCIPLES 4.1 Features and design information 4.2 Examples of applications 5. INSTALLATION 6. DAMAGE ANALYSIS FOR BELLOWS Tests and Standards 6.1 6.2 Damage analysis Medium Temperature Mechanical Stress 742 746 746 746 747 747 748 750 750 752 753 755 755 755 755 756 756 740

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7 4 1 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS MATERIALS AND PROCESS ENGINEERING T a b l e o f C o n t e n t s INTRODUCTION & SERVICES

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Bellows 1. PRODUCT OVERVIEW DESIGN DESCRIPTION MAIN APPLICATIONS Single- convolution bellows for general industry Multiple- convolution bellows for general industry Cable bushings Modular TPE bellows Protective components for shaft joints that are primarily subjec- ted to angular movement. The axial movement is limited. Single-convolution bellows are used when a short stroke and narrow angle are to be sealed They protect axially moving rods and parts of machines against soiling, water spray, dust or the effects of the weather. Depending on their design, they can accommodate movements perpendicular to the axis or a combination of movements (e.g. gear levers) These multiple-convolution bellows seal cable bushings, e.g. in the cab wall of agricultural and construction machinery, against dust, moisture and noise. The mounting tabs allow the cable bushings to be installed very quickly and easily. This eliminates the need for cumber- some and unsafe bonding with liquid sealants Multiple convolution bellows made of TPE, which, depending on the requirements, are offered in the manufacturing length (85 to 200 mm) and connections (in gradations from Ø50 to Ø125 mm) according to the modular principle. The modular tooling concept means the bellows are designed to fit the application exactly. TPE offers the advantage of an increased service life and ozone resistance compared to CR and NBR Ball joint; connection of two tube ends Mechanical engineering; agricultural machinery; construction machinery; shafts and ball joints; tube ends; axle bearings; shift levers Boat building; household appliances; land and construction machinery Cardan joints; piston rods; joy sticks; connection of tube ends to compensate for backlash; overrun brakes of trailers PRODUCT GROUP Bellows 742

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG RANGE [°C] * RANGE CR; NBR; other materials on request ‒40 … +100 Yes Further information on our product portfolio I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P CR; NBR; other materials on request ‒40 … +100 Yes S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P PVC ‒35 … +70 Yes C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B TPE ‒40 … +120 Yes S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 743 X E D N I

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DESIGN DESCRIPTION MAIN APPLICATIONS Steering bellows Multiple-convolution bellows with an adapted geometry for protecting steering linkages General vehicle construc- tion; agricultural and construction machinery Sealing boots Sealing boots in the form of single- or multiple-convolution bellows with or without rein-forcing elements in the area of the connections Ball joints on steering and chassis Rolling bellows for the longitu- dinal shaft A variant of the sealing bellows in S-shape, which „rolls“ around the joint during installation. The bellows is characterized by its high-speed resistance and high resistance to internal pressure, as well as its ease of installation. This variant can be offered with mounting elements on one or both connections Longitudinal shafts; side shafts Propshaft boots Propshaft boots protect joints from corrosion and provide re- liable, long-life sealing against dirt ingress and grease loss Drive shafts in general vehicle construction; construction machinery and commercial vehicles Bellows PRODUCT GROUP Bellows 744

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG RANGE [°C] * RANGE TPE; CR ‒40 … +100 CR ‒40 … +100 No No CR; HNBR ‒40 … +150 No TPE; CR ‒40 … +100 No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 745 X E D N I

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Bellows 2. BELLOWS IN GENERAL Bellows from Freudenberg Sealing Tech- nologies (hereinafter also abbreviated FST) are reliable protective elements that protect components from dirt, splash water, dust, weathering and other exter- nal influences. y elastic connection of two components y protection against injury of persons due to moving machine parts y implementation of optical and aesthetic demands made of the construction 2.1 FUNCTIONS y sealing of components against conta- mination, splash water, dust and we- athering, etc. y protection against loss of lubricants y effective protection of components 2.2 APPLICATION RANGE Freudenberg bellows have become indispensable in general industry as a protective element in a wide variety of applications. y agricultural and construction machinery against wear and corrosion industry y cost savings through extension of the y component function (extension of re- quired maintenance cycles, reduced component replacement, etc.) y sealing for applications involving large relative movements (spherical, axial and radial) as well as axial misalign- ment y mechanical engineering y conveyor technology y medical technology y hydraulic and pneumatic cylinders y trapezoidal and ball screws y electrical engineering (e.g. cable bus- hings in household appliances, ship- building, etc.) FST Website Bellows Product catalog 746

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3. PRODUCT DIVERSITY 3. Product Diversity I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P 3.1 STANDARD BELLOWS The Freudenberg standard range “V6” series offers a large variety of different bellows geometries. With over 200 dimensions, customers can choose from one of the largest sto- cked standard delivery ranges for single- and multiple-convolution bellows. Tailo- red to the most diverse market segments, solutions are offered for both original equipment manufacturers and the after- market. FST’s bellows for general industry are manu factured using custom molds using the vulcanization process. This method offers clear advantages over other manu- facturing processes, such as the dipping process for PVC bellows. It is thus possible to exert a targeted in- fluence on the overall shape, especially in the external area. THE ADVANTAGES AT A GLANCE: y Defined wall thicknesses or profiles in the various functional areas of the bellows y Geometries that always have re- producible dimensions y Mapping of functional geometries, such as retaining collars for clamping elements y Design freedom of the connection geometry y Material selection, material variety The complete standard portfolio is inclu- ded in the product catalog. Here you can quickly and easily filter by the desired dimensions, such as the small (D1) and lar- ge (D2) connection, manufacturing length (L), block dimension (Lmin), inner diameter (Di), outer diameter (Da) and the material. Furthermore, you have access to the corresponding drawings, material data sheets and CAD models. S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Map-marker-edit Clear advan- tages in the vulcanization process S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 747 X E D N I

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Bellows Map-marker-edit Satisfy special requirements and special requests 748 THE ADVANTAGES AT A GLANCE: y Manufacturing according to customer specifications based on customer drawings or as a development service y Wide selection of high-performance materials y The bellows is designed individually according to the customer’s require- ments in terms of shape, stress and media resistance of the material y Comprehensive sampling process and possibility of validation y Customer protection of the design – securing your MR O spare parts busi- ness y Possibility of cost savings by waiving customer protection – assumption of proportional tool costs if suitable for the standard catalog y Customized and durable quality tools – no follow-up costs for wear, repair or replacement y Advice and expertise over the com- plete product life cycle In addition to the proven standard mate- rials CR and NBR, bellows are also availa- ble in other high-performance and effec- tive special materials, e.g. for applications in electrical engineering, medicine and food technology. These include, for ex- ample, HNBR, FKM, ETU-free CR, EPD M and VMQ – all of which are optionally FDA-compliant (→ chapter “Materials and process engineering”, page 29). When selecting a bellows, please also pay attention to the connection geometry. The bellows must match your application not only in terms of dimensions but also in terms of connection geometry. The di- mensions listed in the catalog are subject to the general tolerance for rubber parts DIN ISO 3302-1 M3. All bellows are marked with a tool number to ensure easy identi- fication in the event of a spare parts order. The modular TPE bellows are another part of the catalog portfolio. These are multiple-convolution bellows made of thermoplastic elastomer, which are mo- dular in design. The bellows can be varied in manufacturing length (85 to 200 mm), connection diameter (in gradations of Ø50, Ø63, Ø80, Ø100 and Ø125 mm) and connection areas by regions of different mold inserts, and can thus be adapted precisely to the customer’s application. TPE is characterized by its long service life and increased ozone resistance. 3.2 CUSTOMIZED SINGLE- AND MULTIPLE-CON- VOLUTION BELLOWS Customized products according to custo- mer specifications round off the range. Ba- sed on a customer drawing or as a develop- ment service, the bellows is designed to fit the specific application and produced using state-of-the-art tooling technology. This means that special requirements in terms of shape (e.g. oval or prismatic bellows cross-sections) or special requi- rements for the material in terms of conformity, color or media resistance can already be taken into account in the design.

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3. Product Diversity I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A AREAS OF APPLICATION OF THE MATERIALS (GUIDELINE VALUES) Material Hardness Temperature Dynamic loading Mineral oil and grease resistance CR NBR 42/50 Shore A Approx. 45 Shore A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H –40 … +100 °C –30 … +100 °C Very good Sufficient Sufficient Good R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Tab. 46 Areas of application for standard materials Standard values for the areas of applicati- on of the special materials are available on request. S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 749 X E D N I

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Bellows 4. BASIC PRINCIPLES Connecting part 4.1 FEATURES AND DESIGN INFORMATION x a m L i n m L Bellows Fig. 344 Bellows structure Connecting part Bellows are protective elements consis- ting of a movable bellows part and two connecting parts for fastening. The mo- vable bellows part has a cylindrical, coni- cal or curved contour. The connection components can be in the shape of ring beads, flat flanges, cylindrical couplings or similar. Bellows are generally designed for special applications, which is why the bellows and connection compo- nents come in a wide variety of geometric shapes. Bellows can move axially within the limit values of Lmin (compressed length or block dimension) and Lmax (extended length). If these limits are exceeded, excessive deformation will occur, which can severely impair the functionality of the bellows and, in extreme cases, even cause damage. Bellows cannot absorb significant over- pressures or underpressures, otherwise nonfunctional deformation would occur. Measures to allow internal pressures des- pite this are limited: thicker sections at the transition radii of the individual folds add some strength, but they also reduce the moveability of the bellows. Bracing the bellows section by means of metal rings with a circular cross-section inserted in the fold valleys is not always as successful as desired because of the risk of cutting or tearing. Fig. 345 Connection designs 750

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4. Basic Principles To prevent pressure buildup inside the bellows during axial movements, a ton- gue-shaped cut or a small hole can be made at a suitable point in a bellows fold. Ventilation is also possible via a correspon- ding channel on a connection component. However, such a ventilation opening na- turally limits the tightness of the bellows. Loading of the bellows by torsion should be avoided, as this can cause undefined deformations (“twisting”) of the bellows with excessive local elongations of the material. Such overstretching can dama- ge the rubber structure and significantly shorten the service life of the bellows. Map-marker-edit Optional vent hole I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 751 X E D N I

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Bellows 4.2 EXAMPLES OF APPLICATIONS The movements requiring compensation can be axial displacements and/or deflec- tions around a pivot. Fig. 346 Bellows protects ball-and-socket joint from dirt (spherical movement) Fig. 347 Elastic connection of two pipe ends, bellows compensates for length expansion and radial displacement Fig. 348 Bellows protects the push rod from dirt (axial movement) Fig. 349 Bellows protects the drive shaft joint from contamination and grease loss (axial and circumferential tilting motion) 752

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5. INSTALLATION 5. Installation When selecting the bellows, it should be borne in mind that the folds stand up when the bellows is pushed together into the block position. As a result, the outside diameter of the pleat increases and the in- side diameter may decrease slightly. The bellows wall must not come into con- tact with sharp edges. The bellows must not be jammed during operation, and friction movement of bellows parts on machine parts must be avoided at all costs in order not to risk wear damage. Bellows cannot absorb significant over- pressure or underpressure, otherwise de- formation damaging the bellows would occur. To prevent pressure build-up inside the bellows during axial movements, ade- quate ventilation and exhaust must be provided. Loading of the bellows by torsion should be avoided. In the case of very long, horizontally positioned bellows, it is recommended that the bellows be appropriately suspended to prevent bending and grin- ding on the machine part to be protected. It is also possible to insert support discs inside the bellows folds at suitable inter- vals (→ Fig. 350). Map-Marker-Exclamation Avoid frictional movement and sharp edges Map-Marker-Exclamation Observe the topic of the inner diameter! Map-marker-edit Select suitable suspension of the bellows When installing single- and multiple- convolution bellows, make sure that no pointed or sharp-edged installation tools are used (→ section “Services – Installa- tion and Deinstallation aids”, page 14). Damage can easily occur, but is often difficult to detect during installation. The bellows must not be pinched or over- stretched to prevent structural damage to the elastomer. Bellows should be firmly clamped to the machine parts to be protected, with the type of fastening depending on the shape of the connecting part. If possible, these connecting parts should come to rest in a corresponding receiving groove in order to fix them in their desired position. In the case of hose-like or bead-shaped connection components, the inside dia- meter of the bellows connection should be approx. 3–10% smaller than the dia- meter of the machine-side receiving part so that the bellows connection compo- nents fit tightly. The surface of the connection components does not need to meet particularly high re- quirements, as the surface of the flexible rubber material also adapts to rough sur- faces when appropriately braced. Surface quality of Rz 25 or better is recommended. Due to the natural reduction in the clamping force of stretched rubber, additional mechanical fastening by me- ans of a tensioning strap, hose clip or si- milar is necessary. The clamping element should not be allowed to cut into the bel- lows. Clamping elements with a wide be- aring surface and rounded edges are best suited. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 753 X E D N I

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Fig. 350 Long bellows, horizontal installation with support discs Bellows 754

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6. DAMAGE ANALYSIS FOR BELLOWS 6. Damage analysis for bellows 6.1 TESTS AND STANDARDS Freudenberg bellows for general industry are subject to the general tolerance for molded rubber parts DIN ISO 3302-1 M3. Tests on materials and finished parts for the catalog portfolio are always carried out in accordance with standardized pro- cedures. This includes standard testing of the hardness and density of a production batch as well as regular internal requali- fication related to the dimensions accor- ding to drawings. FST standard materials for the catalog range also undergo an ex- tensive testing program prior to their re- lease and are subject to regular checks during their processing. Fig. 351 Example of mechanical stress on a bellows Mechanical stress and the effects of media, UV radiation, temperature and oxygen lead to a change in the network of the elastomer. This is also referred to as the aging of an elastomer material. The causes for this can be divided into the following areas: If required, additional tests are available on request (→ chapter “Materials and pro- cess engineering – 8. Testing methods“, page 143) are possible. For further infor- mation, see also the → chapter “Services – Test Benches”, page 17. MEDIUM y oxidation by atmospheric oxygen (aging in the narrower sense) y accelerated oxidation caused by heavy metal compounds (e.g. Cu, Mn, Co ...) y hot water or steam aging, aging by hydrolysis y oriented cracking due to static ozone exposure (ozone cracking) y non-oriented cracking under the action of high-energy light and oxygen, occur- rence of “crazing” or “elephant skin” y chemical attack by media (oils, fuels, hydraulic fluids, solvents, chemicals, etc.) y reduction in surface gloss due to ex- posure to warm, humid atmospheres containing ozone – “frosting” (especi- ally in the case of vulcanized materials with light-colored fillers) In addition, evidence of the tests can be provided in the form of test certificates, dimensional reports and material certifi- cates. Please contact your Freudenberg Sealing Technologies customer service re- presentative for availability and prices. 6.2 DAMAGE ANALYSIS External influences are the most frequent causes of damage to bellows. The elastomer from which the bellows are made is subject to constant stresses. More information on this can also be found in the → chapter “Materials and process engineering – 9. Damage analysis“, page 163). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 755 X E D N I

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Bellows Fig. 352 / Fig. 353 Examples of damage due to external injury the → chapter “Material and process en- gineering – 11. Proper storage“, page 178. Other causes of damage to bellows can be improper installation or incorrect selection of the bellows for the desired application (→ Fig. 354). Sharp-edged mounting tools, contact of the joint to be protected with the bellows wall or jam- ming of the bellows folds can often da- mage the bellows unnoticed. Make sure that the inside of the bellows is not in contact with a running spindle, for ex- ample. TEMPERATURE y heat aging without oxygen influence (post-crosslinking, cyclization, tempe- rature reversion) y exceeding the glass transition tempe- rature Tg, glass-like solidification of the elastomer at low temperatures MECHANICAL STRESS y oriented cracking due to dynamic loading (e.g. buckling movement, com- pression, torsion, etc.) To delay the aging process in bellows, different but special anti-oxidants are used (→ section “Material and process engineering – Anti-Ageing Agents“, page 109). These include the addition of sta- bilizers and anti-aging agents such as anti- oxidants and ozone protection waxes during the manufacturing process. Map-Marker-Exclamation Targeted emigration of protective agents The targeted emigration of the protective agents can result in whitish deposits on the outside of the bellows. This is by no means a defect, but a quality feature that ensures longer durability of the bellows. For recommendations on the correct storage of the bellows, please refer to Fig. 354 Example of incorrect bellows selection, fold collapse due to excessive tensile load 756

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6. Damage analysis for bellows Also, a bellows cannot withstand too long a stroke and the overstretching that occurs as a result. For information on cor- rect installation, refer to the → section “5. Installation”, page 753. If you notice damage to a bellows and would like help to clarify the cause, please contact the customer service representa- tive responsible for you. We will also be happy to provide you with support in the form of application advice if undesirable behavior occurs with the bellows used from the catalog portfolio, as well as advice on selecting the right bellows for your application. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 757 X E D N I

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Bellows 758

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I D A P H R A G M S 7 5 9 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS I D A P H R A G M S INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Diaphragms TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. DIAPHRAGMS IN GENERAL 2.1 Requirements 2.2 Features 2.3 Areas of application 3. PRODUCT INFORMATION Long-stroke rolling diaphragms BFA 3.1 3.2 Rubberized fabric 4. BASIC PRINCIPLES Mode of operation and main dimensions Basic types of diaphragms Diaphragm designs 4.1 4.2 4.3 4.4 Parameters 5. DESIGN/DIMENSIONING 5.1 5.2 5.3 5.4 5.5 Operating data and boundary conditions Component stress Permissible load stress Design of the clamping and contacting housing parts Dimensional tolerances for diaphragms 6. MODIFICATION AND COATING 6.1 6.2 Surface treatments Cryogenic deflashing 7. INSTALLATION 7.1 7.2 7.3 Installation preparation Special features in the clamping area Special case: Fabric-reinforced diaphragms 760 762 770 770 770 771 772 772 777 779 779 780 782 783 786 786 787 788 790 791 793 793 794 795 795 795 796

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8. DAMAGE ANALYSIS FOR DIAPHRAGMS Procedure for technical support Procedure in case of complaints 8.1 8.2 8.3 Typical failure patterns for diaphragms 9. MATERIALS FOR DIAPHRAGMS Typical elastomers for diaphragms 9.1 Elastomers 9.2 9.3 Diaphragm fabrics Foils made of PTFE 9.4 9.5 Insert parts 10. TESTING AND VALIDATION OF DIAPHRAGMS 11. SYMBOLS USED Table of Contents 797 797 797 798 800 800 801 805 806 806 808 809 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 761 X E D N I

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Diaphragms 1. PRODUCT OVERVIEW 762 PRODUCT GROUPDESIGNDESCRIPTIONMAIN APPLICATIONSDiaphragmsLong-stroke rolling diaphragms BFALong-stroke rolling dia-phragms are thin-walled, special sensitive diaphragms made from highly elastic materials with fabric rein-forcementLong-stroke rolling diaphragms are used in hydraulically and pneumat-ically-activated control and regulation equipment, pressure switches and pres-sure transducers as well as measuring and display equipment. In the design without fabric, they are used with lower pressuresRubberized fabricRubberized fabrics are special, high-quality fabrics coated on both sides with the appropri-ate elastomer qualities. Special production processes make it possible for even thin layers of elastomer to be applied to the pre-treated fabrics with good adhesion and free of poresMeasuring, regulating or control diaphragms; pump diaphragms; separating diaphragms; flat diaphragmsRolling diaphragms for control and regulat-ing valvesRolling diaphragms in special shapes, such as various flange shapes, bead constructions with or without holes on the cover side or special radius dimensions, with or without fabric reinforcementPneumatic applications; fluid and building technologyMagnetic valves and pressure reducersDiaphragms as separating elements with simultaneous valve position functionsMetallurgical industry; steel/water construction; tunnel boring machines

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1. Product Overview Further information on our product portfolio I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 763 X E D N I MATERIALMAX. TEMPERATURE RANGE [°C] *STANDARD CATALOG RANGE50 NBR 253 with fabric reinforcement‒40 … +80 YesVarious, see FST product catalogVarious, see FST product catalogYesElastomers: VMQ; FKM; EPDM; NBR; HNBR; FVMQFabrics: PA; PES; meta-aramidVarious, see FST product catalogNoMaterials with relevant approvals such as FDA, Drinking Water Guideline UBA, 3-A® Sanitary, WRAS, NSF61, ACS, BFR XXI Cat. 3, USP Class VIVarious, see FST product catalogNo

764

Diaphragms PRODUCT GROUP Diaphragms 764 DESIGN DESCRIPTION MAIN APPLICATIONS Diaphragms for gas regulators Diaphragms for gas meters Diaphragms for speakers Diaphragms for control and regulat- ing valves Diaphragms for shut-off valves High-quality molded dia- phragms with and without fabric reinforcement and/or vulcanized-in valve discs for gas pressure regulators in the high-pressure or low-pressure range High-quality diaphragms made of rubberized fabric for precise measurement behav- ior in the gas meter. With and without a separately formed bead. DFT™ – Dispersed Fiber Technology: fiber-reinforced elastomer materials for complex shaped diaphragms, improved service life and no cross-diffusion. Available in NBR or ECO materials with DIN EN 549 certification Optimally matched materials with outstanding spring and damping properties, specially adapted to meet customer requirements Molded diaphragms with a diameter of up to 1,000 mm. Depending on the pressure and medium, materials with or without fabric reinforce- ment are needed. Sensitive and thin-walled diaphragms for particularly sensitive re-sponse are available Molded diaphragms for shut- off valves in various designs, some with fabric insert and vulcanized-in metal parts, PTFE or Simriz® coating Control, automation and gas control technology Gas meters (industry and household) High-end speakers; tweeters Control and regulating of valves in plant and pipeline construction; breathing masks; respirators Food, pharmaceutical and sanitary technology with relevant approvals

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG RANGE [°C] * RANGE HNBR, NBR, ECO and FKM (each with and without fabric reinforcement) with EN 549 approval; EPDM; VMQ Various, see FST product catalog NBR or ECO with fabric reinforcement Various, see (e.g. polyester, poly amide, FST product catalog meta-aramid) NBR and SBR with special damping properties Various, see FST product catalog CR; EPDM; HNBR; NBR; PVMQ; FVMQ Various, see FST product catalog EPDM; VMQ Various, see FST product catalog No No No No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 765 X E D N I

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Diaphragms PRODUCT GROUP Diaphragms 766 DESIGN DESCRIPTION MAIN APPLICATIONS Diaphragms for pressure switches Sensitive diaphragms for water level control. Pressure control function with thin- walled, fabric-less diaphragms as transmission elements to electrical switching contacts Household appliances; coffee makers, heaters as well as pneumatics Diaphragms for pumps and compressors In modern pumps, both pure elastomer diaphragms and composite diaphragms with a metal support part, fabric and/or PTFE film overlay are used Metering and feed pumps, double diaphragm pumps, AdBlue® pumps, vacuum pumps Diaphragms made of rubberized fabrics Diaphragms made from rub- berized fabrics. Deep-drawn diaphragms are cost-effective alternatives to pressed molded membranes. Rubberized fabric materials with polyester and polyamide carrier fabrics Storage diaphragms Diaphragms made of materi- als with extremely low gas permeation and good low-temperature flexibility for use in industrial hydraulics. As problem solvers for pressure surges in piping systems Fittings; industrial controllers; pumps Power units for general industry; pressure accumu- lators in hydraulic circuits Pressure accumulator bladders In compression or injection molding, and in some cases multipiece fabricated, complete bladders. Made of diffusion-tight compounds Agricultural and construc- tion machinery; materials handling and hydraulic circuits in general industry and aerospace

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG RANGE [°C] * RANGE EPDM; NBR; VMQ Various, see FST product catalog CR; EPDM; FKM; HNBR; NBR Various, see FST product catalog CR; ECO; EPDM; NBR Various, see FST product catalog AU; ECO lead-free; EPDM; HNBR; CIIR; NBR Various, see FST product catalog ECO; CIIR; NBR; HNBR Various, see FST product catalog No No No No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 767 X E D N I

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DESIGN DESCRIPTION MAIN APPLICATIONS Silicone and fluoro- silicone diaphragms Pressure Compensa- tion Valve DIAvent Rolling diaphragms and control diaphragms made of oil-resistant solid silicones with outstanding tempera- ture stability. Also, for blow- by applications Functional components con- sisting of a combination of several nonwoven layers with excellent bidirectional air permeability and simultane- ous water tightness (IP67). With an elastomer umbrella valve for reversible emergen- cy degassing Pneumatic applications; sanitary engineering; oil mist separators; condensate separators Ventilation and emergency degassing of batteries in electric vehicles DIAvent HighFlow Same features like the DIAvent but 4 times higher emergency degassing rate Ventilation and emergency degassing of batteries in electric vehicles DIAvent light Same features like the DIAvent but no emergency degassing function (just breathing) Ventilation of batteries, in- verter, dry running e-motors Diaphragms PRODUCT GROUP Diaphragms 768

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1. Product Overview MATERIAL MAX. TEMPERATURE STANDARD CATALOG RANGE [°C] * RANGE VMQ; FVMQ; optionally with fabric reinforcement Various, see FST product catalog No PBT housing for fire protection class UL94 V0 ‒40 … +120 No PBT housing for fire protection class UL94 V0 ‒40 … +120 PA housing for fire protection class UL94 V0 ‒40 … +120 No No I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 769 X E D N I

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Diaphragms 2. DIAPHRAGMS IN GENERAL In certain applications, components must be flexibly connected to each other and at the same time ensure that a tightly sealed partition is provided for. These demands can generally best be met with diaphragms. Freudenberg Sealing Tech- nologies (hereinafter also abbreviated FST) offers more than 400 different elas- tomer compounds for diaphragm applica- tions. These can be used on a project basis to meet customer-specific requirements. 2.1 REQUIREMENTS y operational safety for widely varied media deployments y solutions for control, accumulator and pump functions y fabric insert and/or layer, depending on the pressure load y allowance for unilaterally or bilaterally applied pressure y optimal design of stroke to bore ratio 2.2 FEATURES y customized solutions based on the 4 basic types: flat diaphragms, dished diaphragms, convoluted diaphragms and rolling diaphragms y ultimate precision, thanks to the most advanced FEM calculations used in designing them y optional PTF E/TF M foil layers against aggressive media FST Website diaphragms Product catalog 770

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2. Diaphragms in general y special metal or plastic inserts for load transmission and bracing y qualitative high-grade material con- structions, contingent upon the oper- ating conditions (e.g. NBR, HNBR, ECO lead-free, AU, FKM, FFKM, etc.) 2.3 AREAS OF APPLICATION The application spectrum of diaphragms extends from conventional control and sealing elements for valve technology through to sophisticated tasks for aero- space. y valves and fittings y actuators y pumps and compressors y accumulator diaphragms in hydraulics y aerospace industry y plumbing technology y respirator masks y foodstuffs industry y etc. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 771 X E D N I

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Diaphragms 3. PRODUCT INFORMATION In nearly all sectors of industry, designers need to flexibly connect together com- ponents, to separate spaces between components and at the same time to create a leak-proof separation in certain applications. These tasks can almost always be ad- dressed by using a diaphragm made of highly elastic materials. Very different requirements in relation to mechanical, thermal and chemical loads result in custom designs in the majority of cases. Our specialists with know-how from many years of experience are available to prepare these custom designs. Besides customized diaphragm shapes, we also offer standard products that are presented in the following section. 3.1 LONG-STROKE ROLLING DIAPHRAGMS BFA PRODUCT DESCRIPTION Long-stroke rolling diaphragms are thin- walled, special sensitive diaphragms made of highly elastic materials with fabric reinforcement. These comprise: PRODUCT BENEFITS y long-stroke rolling diaphragms y rubberized fabrics (fabric rubberized on both sides) y sheet goods Rubberized fabrics and sheet goods are predominantly used for the economic manufacture of flat diaphragms or seals by punching. The diaphragm’s slender thickness along with its elevated height, relative to the diameter, provide the following advantages: y Low, almost constant resistance to movement over the entire stroke y Considerably greater stroke lengths compared to conventional dia- phragms with the same diameter y Effective area remains the same over the entire stroke y No additional resistance to move- ment on starting or on change in direction of movement; no notch point in the operating range y Lower requirements for pistons and cylinders compared to lip seals 772

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3. Product information Map-Marker-Exclamation A mounting sleeve needs to be used. Do not use a screwdriver FITTING & INSTALLATION In the case of long-stroke rolling diaphragms with a fabric layer, the fabric layer must be on the non-pressurized side. The diaphragm is inverted before fitting. If the rolling convolution that has formed arches upwards while performing this step, a mounting sleeve will need to be used. D o not use a screwdriver! Another possible fitting method: fit the inverted rolling diaphragm to the piston, place bead in the groove and push the piston into the cylinder. The rolling convolution will then be formed. The piston needs to be secured against twisting after fitting to avoid the formation of a skewed convolution. A plain washer is sufficient as the spring support. Stroke limiting is always to be provided for. The rolling area for the diaphragm must be finely machined and polished. The transition radii on the clamping flange, piston base and cover plate must be smooth and free from scoring. Map-Marker-Exclamation Ventilation bore APPLICATION Long-stroke rolling diaphragms are used in hydraulically and pneumatically-activated control and regulation equipment, pres- sure switches and pressure transducers as well as measuring and display equipment. In the design without fabric, they are used at lower pressures. MATERIAL Standard material: 50 NBR 253 based on acrylonitrile-butadiene rubber (NBR) with or without polyester fabric. Rolling dia- phragms made of silicone rubber, fluoro rubber and EPD M with fabric are only produced to a height of Hmax = 0.6 Dg (Dg = cylinder diameter). Special tools are required for fluoro rubber. When select- ing the appropriate material, the exact operating conditions should be taken into account. OPERATING CONDITIONS The standard BFA range made from nitrile rubber with fabric reinforcement for use in compressed air and mineral oils permits operating pressures up to 10 bar and test pressures up to 15 bar. Special qualities are available on request for applications involving town gas and natural gas, gas- oline and brake fluids as well as for high thermal loads. In operation, even with piston return, there must be a low pressure difference of approx. 0.15 for all designs, otherwise folds or kinks will form in the rolling convolution. This counter pressure can be achieved using a regulator valve. A ventilation bore must be provided to prevent a pressure build-up on the non-pressurized side. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 773 X E D N I

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Diaphragms INSTALLATION TYPES Mounting sleeve Installation by pushing in Installation with a sleeve Formation of a double convolution Rk Rw H Sa Lc Dg Dk Df W Dk Dg Hb as supplied Sb Lk Ventilation bore Stroke limitation Ventilation bore R= D 2 D AØ installed condition Fabric side +0.2 Wg Hg -0.1 RC Hl Rl DNØ Wl -0.1 DgØ Fastening plate (if the center hole is provided in the BFA) RI, RC and Rk polished without scoring Tensioning detail bead 774

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3. Product information INSTALLATION DIMENSIONS CYLINDER Ø Dg UP TO 60 mm UP TO 100 mm UP TO 150 mm > 150 mm I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H INSTALLATION DIMENSIONS Piston Ø Groove Ø Piston radius Cover radius Groove depth Groove width Rim width Rim height Rim radius Dk DN Rk RC Hg Wg WI HI RI DIAPHRAGM DIMENSIONS Flange Ø Wall thickness Flange bead Radius Df W Hb Rw Dg −5 Dg +15 Dg −10 Dg +21 3.5 2.0 3.0 4.0 3.5 2.3 1.75 4.5 2.0 4.0 5.5 5.0 3.1 2.5 Dg −10 Dg –10 Dg +27.5 Dg +27.5 5.8 2.0 5.0 7.2 6.5 3.5 7.0 2.0 5.0 7.2 6.5 3.5 3.25 3.25 R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P Dg +14 Dg +20 Dg +26 Dg +26 0.45 3.6 1.75 0.55 5.0 2.50 0.8 6.3 3.25 1.0 6.3 3.25 C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B MINIMUM LENGTH OF FINELY MACHINED AREAS On the piston On the cylinder Lk Lc 0.5 (H + Sa) 0.5 (H + Sa) 0.5 (H + Sa) 0.5 (H + Sa) 0.5 (H + Sb) 0.5 (H + Sb) 0.5 (H + Sb) 0.5 (H + Sb) S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 775 X E D N I

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Diaphragms INSTALLATION DIMENSIONS CYLINDER Ø Dg UP TO 60 mm UP TO 100 mm UP TO 150 mm > 150 mm DIAPHRAGM STROKE in one direction max. in the opposite direction max. FASTENING PLATE Sa Sb A D H −8 H −8 H −14 H −14 H −20 H −20 H −20 H −20 Dk +2.9 Dk +4.1 Dk +5.6 Dk +6 1.5 3.0 4.0 5.0 776

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3. Product information Main areas of use: y measuring, regulating or control dia- phragms y pump diaphragms y separating diaphragms y flat diaphragms MATERIAL Acrylonitrile-butadiene rubber (NBR), chloro-butadiene rubber (CR), ethylene- propylene-terpolymer rubber (EPDM), epichlorohydrin rubber (ECO) and fluoro elastomer (FKM) are preferably used as elastomers. Polyester (PES), polyamide (PA) and spun rayon (ZW) are used for reinforcement. The coating contains one of the elastomers listed, depending on the application. OPERATING CONDITIONS The media resistance is dependent on the coating material and fabric. This can be found in the table of stock articles (→ page 778). The maximum tensile force defines the pressure resistance of the rubberized fabric. FITTING & INSTALLATION Adequate compression (10% of sheet thickness) as well as a score-free surface on the metal or plastic parts are prereq- uisites for clean sealing in the clamping area. 3.2 RUBBERIZED FABRIC PRODUCT DESCRIPTION Rubberized fabrics are special, high-quality fabrics coated on both sides with elasto- mers with appropriate properties. Special production processes make it possible for even thin layers of elastomer to be applied to the pre-treated fabrics with good ad- hesion and free of pores. PRODUCT BENEFITS Flat diaphragms can be punched from these rubberized fabrics without diffi- culty. Manufacturing of molded dia- phragms takes place by embossing them at high temperatures, here certain restrictions in relation to the diaphragm height that can be attained must be taken into account depending on the fabric quality and material thickness. APPLICATION Diaphragms made from rubberized fabric have the task of forming a leak-proof yet flexible separation. Rubberized fabrics are designed to suit the mechanical, thermal and chemical loads for the respective ap- plication. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 777 X E D N I

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Diaphragms RUBBERIZED FABRIC DESIGNS CODE ELAS- TOMER FABRIC a) NOMINAL WIDTH [m] MAX. TENSILE FORCE [N/mm] THICK- NESS [mm] TOLE- RANCE COLOR OPERATING TEMPERA- TURE MIN/MAX [°C] b) MT 479 NBR MT 481 NBR MT 496 NBR PA PES PA 1.40 1.40 1.40 11 50 50 0.17 ±0.03 Blue –25 … +90 0.90 ±0.07 Blue –25 … +90 1.10 ±0.15 Red –30 … +90 MT 513 NBR PES 1.40 20 1.00 ±0.10 Black –45 … +90 MT 489 NBR PA 1.50 40 0.68 ±0.07 Red/ Green c) –20 … +90 MT 490 NBR PA 1.50 24 0.40 ±0.05 Green –20 … +90 MT 510 CR PA 1.50 50 1.10 ±0.15 Black –30 … +90 MT 511 EPDM PA 1.50 24 0.55 ±0.06 Black –45 … +120 MT 504 ECO PA 1.50 30 1.00 ±0.10 Black –35 … +130 MEDIA Fuels; heating and fuel gases; mineral oils; greases; inorganic acids and bases; flame resistant hydraulic fluids (HFA, B, C); oil-bearing com- pressed air; water up to +80 °C Diesel fuels; mineral oils; oil-bearing compressed air; heating oils; water up to +80 °C Oil-bearing air; water (ozone and UV resistant) Hot water; steam; glycol-based brake fluid Fuels; oils; greases; air a) PA = Polyamide; PES = Polyester b) Guide values in the delivered state – Validation by customer for the respective use case is absolutely necessary c) Red = Fuel side; Green = Oil side 778

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4. BASIC PRINCIPLES 4. Basic Principles Diaphragms made of elastic rubber ma- terials are tasked with establishing a sealed and, at the same time, flexible par- tition between two component chambers and to enable volumetric changes of the separate chambers. By virtue of their basic function, they can also be characterized as flexible sealing components. BENEFITS OF DIAPHRAGMS Diaphragms offer several advantages compared to contact seals: y Leak-free y There is no requirement for lubri- cation, therefore they are mainte- nance-free y No frictional losses y Minimal hysteresis with the appro- priate constructive design y No breakaway force (“stick-slip effect”) y Minimal wear due to clear roll-away movement y Substantially reduced demands for tolerances and surface quality of the adjacent components make cost savings in component manu- facturing possible In light of these conditions, there are two main applications or functions for dia- phragms: y piston seal: in a switching, control or indicator de- vice, hydraulic or pneumatic pressure acting on the effective surface of the diaphragm is converted into a linear shaft force for actuation. In a pump, an intro duced rod force is conversely con- verted into delivery pressure y separating function: this function simply involves separating chambers – which have virtually the same pressure level – from each other by means of a slightly movable and flexible partition. Applications in the area of accumulators are a good ex- ample of this The fundamental interrelationships can be best explained using the example of the pump or control diaphragms depicted in → Fig. 355. 4.1 MODE OF OPERATION AND MAIN DIMENSIONS The operating area of the diaphragm is restricted outwardly by the housing di- ameter and inwardly by the piston diam- eter. The diaphragm is statically fitted into the housing and – if necessary – on the piston, to seal. A rolling gap is located between the housing and the piston, over which the flexed area of the diaphragm is more or less tightly “stretched.” If there is a pressure differential between the upper and lower side, then the flexed area is depressed into the rolling gap by the pressure load, initially taking on an arched form. As with a thin-walled pipe under internal pressure, pressurizing forc- es and forces running tangential to the arc in the diaphragm wall are kept in balance. The radius of the curve in the flexed zone is dependent on the length of the freely available surface line between the clamp- ing point on the housing and the piston, as well as the clearance between the I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 779 X E D N I

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Diaphragms Map-marker-edit Cost savings with sheets and rolled goods 780 clamping point and the position of the piston at the clamping plane. Considera- tion should be given to an adequate flexed zone surface length when design- ing this. Flat diaphragms Flat diaphragms (→ Fig. 356) can only be utilized with relatively short strokes, but can of course have pressure applied bi- laterally. When travelling through the stroke, the flexed area “rolls” up in the rolling gap. Areas of the diaphragm wall then move from the piston to the housing and vice versa, thereby undergoing an enlargement or, respectively, reduction in diameter. Dg U R b HO HU Hg R DK DWU P F DWO Fig. 355 Main dimensions/mode of oper- ation 4.2 BASIC TYPES OF DIAPHRAGMS The multitude of designs can be traced back to just a few basic types: y flat diaphragms y dished diaphragms y long-stroke rolling diaphragms (= special form of the dished diaphragm) y convoluted diaphragms The main distinguishing feature in each case is the attainable stroke Hmax for a given housing diameter Dg, as well as the type of permissible pressurization (one-sided, two-sided) and the measure of dependence of the effective diameter Dw from the stroke. As a rule, the effective diameter changes greatly with the stroke. The low stroke heights often still permit so-called “swaged installation” to reduce the component stress under pressure load (→ Fig. 357). The piston is axially displaced in the hous- ing before the diaphragm is clamped in place. The compression should be selected to be high enough that the necessary elongation compensates for the free diaphragm surface at the end position of the piston. This avoids an elongation of the diaphragm surface. If sheets or rolled goods are used as semi finished products, then the manu- facturing of an expensive, item-specific vulcanization tool can be dispensed with. S DA DA Dg Dm DK P1 b 2 b b 2 U b U h Hmax P2 Fig. 356 Flat diaphragms

781

4. Basic Principles D D + 2 I ' A= A’ DA’ LO LO h 'I X Detail X Long-stroke rolling diaphragms The long-stroke rolling diaphragm (→ Fig. 359) is considered a special case of the dished diaphragms, which is everted dur- ing installation. In the design with fabric re- inforcement, the potential stroke is limited by the deep-drawing capacity of the fabric. Rolling diaphragms must be supported on the outside by the housing and on the inside by the piston. This provides for a quasi- stroke- independent, constant effective diameter. Rolling diaphragms always require a pressure differential to the rolling convolution, as do convoluted diaphragms, as otherwise they would be everted by the pressure. Fig. 357 Swaged installation of flat dia- phragms Dished diaphragms Dished diaphragms (→ Fig. 355) can, like flat diaphragms, have pressure applied bi- laterally, yet allow substantially longer strokes. With this design type also, the ef- fective diameter is extremely dependent on the stroke. b 2 b s h D A h S b 2 b DA DA Dg Dm DK P1 Hmax I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B b 2 b A D D D D g m k b 2 b P2 P 1 H max P 2 Fig. 358 Dished diaphragms Fig. 359 Long-stroke rolling diaphragms Convoluted diaphragms This design type (→ Fig. 360) involves a rolling convolution with an arched cross- sectional area, even in an unloaded state. S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 781 X E D N I

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Diaphragms 782 As long as limitations in the stroke height are taken into consideration, a virtually stroke-independent effective diameter can be attained. It should be kept in mind that the very lim- ited plasticity of the fabric restricts its pos- sibilities for usage from a manufacturing compatibility point of view. Convoluted diaphragms always require a pressure differential toward the rolling convolution in order to preclude a folding over of the rolling convolution. S h b 2 U b P1 Dm DA DA Dg Dm DK b 2 b Hmax 1 2 U Hmax P2 Fig. 360 Convoluted diaphragms 4.3 DIAPHRAGM DESIGNS The different fabric types that can be used are addressed in more detail in → “9.3. Di- aphragm fabrics,” page 805. Diaphragms with support made of PTFE With aggressive ambient media and con- veying media, as can be found with pump applications, the chemical resistance of the elastomer can be inadequate. In this case, it is possible to protect the basic material of the diaphragm by applying a foil made of PTFE to protect the surface facing the medium, thus increasing the service life. 4.4 PARAMETERS The behavior of a diaphragm can be ap- proximately characterized by means of the parameters stroke, effective diameter or, respectively, effective area, mean diameter and modulus of elasticity. Diaphragms with fabric reinforcement All forms of diaphragms can be produced as purely elastomer diaphragms or also with fabric reinforcement. Stroke The absolute stroke travel Hg comprises the portions of Ho above and Hu below the clamping plane: With these, the reinforcing fabric is em- bedded in the middle of the diaphragm cross-section (insert) or “placed upon” a surface (support). The support must thereby always be on the non-pressurized side (e.g. outside of the rolling convolu- tion), as otherwise the elastomer layer would be separated from the fabric sheet by the pressure and the diaphragm would be destroyed. [1] Hg = Ho + Hu When dimensioning, the larger of the two values is to be considered to be a critical case. With a view towards optimal func- tion and service life, the stroke should only be deduced from the change in shape of the diaphragm and not from an elongation of the diaphragm surface.

783

4. Basic Principles Effective diameter, effective area Under pressure load, the diaphragm brac- es itself on the piston and thus provides a contribution towards the linear shaft force. The diameter which has an effect on the linear shaft force – the effective diameter Dw, is dependent upon the stroke position and lies between the piston dia- meter Dk and the housing diameter Dg. Rolling gap The gap “spanned” by the diaphragm between the housing and the piston is designated as the rolling gap b: [4] b = (Dg – Dk)/2 In the first approach, it can be established that: It is generally applicable that: [5] b ≈ 0.15 Dg Housing diameter When specifying parameters, the pre- ferred approach is to use the housing diameter as it is derived directly from the available installation space or, respective- ly, allows for direct estimation of the nec- essary installation space. With the ar- rangement for the rolling gap according to → equation 5, the following applies: [6] Dg = Dm /0.85 ≈ Dw/0.85 [2] Dk ≤ Dw ≤ Dg The effective diameter can be determined quite well as the lowest or highest point of the circular arc of the flexed area (= dia- meter of the center of the circular arc). Only the effective area lying inside this diameter contributes to generating the linear shaft force. Mean diameter The mean diameter refers to the mean value of the piston and housing diameter. In the home position, it coincides well with the effective dia meter: [3] Dm = (Dg + Dk)/2 = Dw(H=0) ≈ Dw(H) DIAPHRAGM DESIGNS MAX. STROKE Hmax APPLIED PRESSURE Flat diaphragms Dished diaphragms Convoluted diaphragms Long-stroke rolling diaphragms ≤ 0.1 Dg ≤ 0.3 Dg ≤ 0.3 Dg ≤ 1.7 Dg bilaterally bilaterally unilaterally P1 > P2 unilaterally P1 > P2 Tab. 47 Characteristic values for diaphragms CHANGE OF EFFECTIVE DIAMETER Dw BY MEANS OF STROKE H very large large small none I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 783 X E D N I

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Diaphragms Elasticity modulus The modulus of elasticity (e-modulus) for elastomers is, in contrast to that of steel, not constant but rather dependent on the hardness of the elastomer, the temperature, the elongation and deformation speed. y the e-modulus increases with increas- ing deformation speed (dynamic hard- ening). When dimensioning, it is best to use the quasistatic case for the sake of simplicity. Regarding the compo- nent stress, this is also considered the “critical case” y with an increase of the secant between the original state and a 20% elongation of the tension elongation diagram, an approximate value for the modulus of elasticity in the dimensioning area is obtained 2 m m N n / i E y t i c i t s a e l f o l s u u d o M 8 7 6 5 4 3 2 1 0 T = +20°C T = +90°C that this characteristic value be discussed with the compound manufacturer. Characteristic curves If the linear shaft force F is applied through- out the stroke, then a characteristic curve is derived. As the linear shaft force depends on the set pressure and effective area or, respectively, effective dia meter, the char- acteristic curve is then essentially deter- mined by the dependency of the effective diameter of the stroke. The choice of the basic diaphragm types plays a decisive role here. The principal correlation is depicted in → Fig. 362. As the change of the char- acteristic curve increases at the end of the stroke end position, the characteristic curve progression allows for optimization by the choice of the operating area. By overextending the diaphragm (Hg < Hmax), the peripheral areas can be “truncated,” providing for a more favorable overall characteristic curve with reduced influ- ence on the stroke. Linear shaft force F Loading pressure p 40 50 60 70 80 Hardness in Shore A Fig. 361 Elasticity modulus The dependency of the E20% modulus of elasticity upon the elastomer hardness and temperature is exemplarily depicted in → Fig. 361. As the modulus depends on the compound, it is recommended Operating area W Stroke Hg Fig. 362 Linear shaft force 784

785

4. Basic Principles → Fig. 363 schematically shows the pro- gression of the inherent resistance as a function of the diaphragm stroke. The increase in resistance is particularly large near the end positions of the dia- phragm. As with the characteristic curve, the influence on the stroke can be re- duced by super elevating the diaphragm (Hg < Hmax). Inherent resistance Inherent resistance is the term used to describe the resistance that a diaphragm imposes, excluding all outside influences, on the movement from one end position to the other. As a rule, this resistance is determined by measuring the pressure necessary to overcome the resistance. It is caused by tensile stress in the surface of the diaphragm during stretching in the course of the uncoiling movement and through bending stress during outward travel of the diaphragm from the manu- factured position. Diaphragm stroke H Hg Hmax Lifting pressure P Fig. 363 Inherent resistance I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 785 X E D N I

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Diaphragms 5. DESIGN/DIMENSIONING 5.1 OPERATING DATA AND BOUNDARY CONDITIONS The dimensioning of a diaphragm is essentially determined by the following operating data: y the type of device (e.g. a cylinder oper- ating under rough operating conditions or a measuring device that places high demands regarding inherent resist- ance and hysteresis) y max. stroke with a subdivision in regard to the clamping plane y pressure (operating pressure and/or test pressure) y effective diameter (as a function of the stroke, if applicable) y ambient media y operating temperature range y actuation frequency y service life When dimensioning the diaphragm, it is recommended that the procedure de- scribed below be followed. Step 1: Select the design type according to → Tab. 47 Before selecting, the housing diameter Dg and diaphragm stroke, Hmax should be de- rived from the operating data. The ratios in the equations [7] through [10] are help- ful in this regard: For a pump diaphragm, the volumetric displacement can be estimated with: [7] V = π/4 Dw 2 Hg The piston force can be derived with: [8] Fk = π/4 Dw 2 p Optimal usage of the diaphragm stroke can be achieved with: [9] Hg = Hmax During the first step, the correlation be- tween the housing and the effective diam- eter can be established (→ equation [6]): [10] Dw = 0.85 Dg As the stated relationships only provide approximate values, it is recommended that a safety factor of approx. 10% be assigned to the regulating power and the volumetric displacement. Step 2: Dimensioning of the diaphragm In dimensioning, the design of the dia- phragm and adjacent components – such as the housing and piston – are deter- mined. When designing the diaphragm, the manufacturing compatibility aspects must also be considered in addition to the strictly functional aspect. An examination and optimization of all dimensions by the diaphragm manufacturer is definitely recommended. The aspects listed below should be given particular attention: The values for Hmax apply in any case for a symmetrical distribution of the absolute stroke travel above and below the clamp- ing plane, and this is: [11] Hu max = Ho max = Hmax/2 With asymmetric stroke distribution, the absolute stroke travel Hg is thus always smaller than the maximum possible stroke Hmax. In order to minimize the bending stress and inherent resistance, the dia- phragm thickness s is generally made to be as thin as possible. 786

787

5. Design/Dimensioning Here, however, the specified limits of the material and manufacturing method must always be observed. In general, it is recom- mended that fabric-free diaphragms only be used for pressures of less than approx. 2 bar. With higher pressures, thin-walled, fabric- rein forced diaphragms should be used instead. As a result of the uncoiling movement, bending stress arises in the clamping area as well as in the flexed area. In order to limit this loading to non-critical levels, clamping ribs and rolling fold areas should be chosen for completely uncoiling diaphragms, depend- ing on the diaphragm thickness (→ Fig. 364). [12] Clamping rib ρ ≥ 2 s [13] Rolling fold span b ≥ 6 s Attention should also be paid to the in- structions on → “5.4 Configuring the clamping and contacting housing parts,” page 790. U S R b Fig. 364 Bending stress 5.2 COMPONENT STRESS After selecting the design and dimen- sioning of the diaphragms, the acting stress during operation needs to be looked into. Step 3: Examination of the diaphragm stress Typical operating conditions for diaphragms are unilateral pressure and an axial shifting between the piston and the housing. This essentially results in two different load stresses in the diaphragm wall: y elongation stress and tensile stress in the circumferential direction as a result of a change of the diameter during the uncoiling movement (→ elongation stress/tension in circumferential direc- tion) y tensile stress in the radial or axial direc- tion as a result of the pressure differen- tial p (elongation stress/tension as a re- sult of the pressure differential) A multiaxis state of stresses thus results. In practice, however, no reference stress load is calculated for the two components; instead, they should be considered indi- vidually. Elongation stress/tension in the circum- ferential direction The distension in the circumferential direction as a result of the change of the diameter during the uncoiling movement (→ Fig. 365) is highly dependent on the shapes of the diaphragms, the installation space and the stroke. The max. circumferential elongation appli- cable to a rolling diaphragm is: [14] εu max = Dg/Dk − 1 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 787 X E D N I

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Diaphragms 788 The maximum circumferential elongation for flat diaphragms, convoluted and dished diaphragms must be determined using the appropriate methods. Dg DK Fig. 365 Elongation as a result of uncoiling movement Elongation stress/tension as a result of pressure differential Because diaphragms have less inherent stiffness due to their geometry, an arced diaphragm cross section is formed under pressure (→ Fig. 366). If the diaphragm is viewed while disregarding the curvature, upon first approximation as a straight pipe under internal pressure, then the tensile force in the diaphragm wall is derived from the “boiler formula” for thin-walled pipes: [15] σp = p R/s By applying Hooke’s Law for the uniaxial state of stresses: [16] σ = E ε ... the elongation is derived for: [17] εp = p R/(s E) Recommended values for the modulus of elasticity E are stated in → Fig. 361. The force Fp per circumference length l is required as a parameter for fabric rein- forced diaphragms. From the equation [15], the result is as follows: [18] Fp/l = σ' = p R P R S Fig. 366 Load stresses from a pressure differential 5.3 PERMISSIBLE LOAD STRESS When assessing the load stress deter- mined according to → section “5.2 Com- ponent stress,” a distinction must be made between diaphragms with and without fabric reinforcement. For fabric-free diaphragms under pressure load, the specification of a maximum elongation has proven to be effective in practical situations. This is due to the structure of the elastomers, which are composed of fiber molecules that are interlaced with one another.

789

5. Design/Dimensioning With fabric reinforced diaphragms, the low percentage of contact area of the elastomers is disregarded and it is assumed that the tensile stress is carried solely by the fabric. The circumferential elongation as a result of the uncoiling movement should be examined and the minimum strength of the fabric determined: The tensile strength σ’B of fabric is deter- mined in tensile trials as the maximum tensile force in regard to the sample width and this information can be obtained from the manufacturer. By making use of a safety factor, consideration is given to the fact that the fiber direction around the periphery deviates in part from the direction (radial) of the stress. In addition, with fabric, the dependency of the tensile strength on the operating temperature needs to be considered as well. Design examples: rolling diaphragms with a fabric layer In a control valve, a rolling diaphragm is to be used according to the following boundary conditions: y Housing Ø y Piston Ø y Pressure differential p = 10 bar ≈1 N/mm2 Dg = 100 mm Dk = 90 mm y from the geometry, it can be deduced that: b = (Dg − Dk)/2 = 5 mm R = b/2 = 2.5 mm y with equation [14]: εu max = 0.11 = 11 % ≤ 15 % → i.O. y with equation [18]: Fp/l = 2.5 N/mm y from Tab. 48: σ'B ≤ Fp/l/0.2 = 12.5 N/mm The maximum circumferential elonga- tion lies within the permissible range, the minimum tearing resistance for the fabric is 12.5 N/mm. Convoluted diaphragms without fabric For a fabric-free convoluted diaphragm with a wall thickness of 2 mm, the rolling convolution radius at a pressure differen- tial of 1 bar (≈ 0.1 N/mm2) can be graph- ically determined as 15 mm. PARAMETER PERMISS. LOAD STRESS WITHOUT FABRIC WITH FABRIC Circumferential elongation (mean value) Elongation due to internal pressure Force per width εU εp Fp/l → a) → b) → b) ≤ 30 % ≤ 20 % – Tab. 48 Diaphragm parameters a) Elongation stress/tension in the circumferential direction b) Elongation stress/tension as a result of differential pressure ≤ 15 % – ≤ 0.2 σ'B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 789 X E D N I

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Diaphragms 790 If undercutting occurs, buckled folds and premature wear and tear can be expected (→ Fig. 367). In the clamping in the housing or, as the case may be, on the piston, the diaphragm is to be clamped and bolstered against the pressurizing forces. This is often com- bined with the sealing of the parting plane. These tasks can be carried out using various clamping geometries. The follow- ing are often used: y design in the form of a flat seal: to improve the sealing effect, both flanges can be provided with offset- positioned flat beads or grooves. y circular, thick-bead (O-ring): both flanges have grooves for inserting the beads y semicircular sealing bead (half O-ring): the groove is only applied in one flange, the other flange is made to be flat. For design examples, please see → “Dished diaphragms” (long-stroke rolling dia- phragms), page 781 y the bead and groove geometry must be designed so that a compression of 20% to 30% is attained It should also be considered that elastomers are nearly incompressible. The clamping groove should be made to be large enough to accommodate the compressed volume, even allowing for possible thermal expan- sion – or swelling as a reaction to media exposure – with sufficient safety. What is sought is the minimum Shore hardness of the elastomeric material. → Equation [17] with → Tab. 48: Emin = p R/(s εp zul) = 3.75 N/mm2 From → Fig. 361: Hardness ≥ 61 Shore A at operating temperature RT Hardness ≥ 69 Shore A at operating temperature +90 °C 5.4 DESIGN OF THE CLAMPING AND CONTACTING HOUSING PARTS As a matter of principle, no sharp edges are allowed in the contact area of the diaphragm, as these inevitably lead to high bending stress or mechanical damage during uncoil- ing movements and thus to failure. The transitions from the clamping plane or, respectively, piston surface to the cylinder wall are to be rounded in order to avoid tension peaks (→ “4.2 Basic types of diaphragms,” page 780 and → “5.1 Operating data and boundary condi- tions,” page 786). The following is appli- cable to the surface quality of all housing parts that come into contact with the diaphragm, and where there is a possibil- ity of relative movement: Rz ≤ 10 µm Where a rolling convolution has been formed (e.g. with a rolling diaphragm or a highly elevated dished diaphragm), the housing and piston are to be designed so that a reliable bracing is provided for.

791

5. Design/Dimensioning WALL AND BEAD THICKNESS S [mm] TOLERANCE [mm] ≤ 0.5 < 0.5 … 3.0 < 3.0 … 6.0 < 6.0 … 10.0 ±0.05 ±0.10 ±0.15 ±0.20 Tab. 49 Thickness tolerances for molded diaphragms Closer manufacturing tolerances can be adhered to with stamped diaphragms made of rubberized fabric. Thus, DIN ISO 2768 m applies to the diameter tolerances of stamped flat diaphragms (→ Tab. 50). DIAMETER D [mm] TOLERANCE RANGE AS PER DIN 2768 M [mm] < 3 … 6 < 6 … 30 < 30 … 120 < 120 … 400 < 400 … 1,000 ±0.1 ±0.2 ±0.3 ±0.5 ±0.8 Tab. 50 Diameter tolerances for diaphragms made of rubberized fabric It should be noted that, with greater wall thicknesses, a concave cut surface can possibly occur through deformation of the material during the cutting process. Undercutting rolling convolution on a support with a dish Correct rolling convolution on a support with a piston Fig. 367 Bracing of the rolling convolu- tion by means of a piston 5.5 DIMENSIONAL TOLERANCES FOR DIAPHRAGMS In general, DIN ISO 3302 Part 1 “Rubber – Tolerances for Products – Dimensional Tolerances” applies to the diameter tol- erance of molded diaphragms and form- pressed diaphragms made of rubberized fabric, whereby the tolerance class M2 applies for diaphragms without fabric and the tolerance class M3 for diaphragms with fabric (→ Tab. 51). The tolerances listed in the following, already restricted with regard to DIN ISO 3302-1, apply to the wall and bead thickness- es of form-pressed diaphragms (→ Tab. 49). I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 791 X E D N I

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Diaphragms DIAMETER [mm] less than 6.3 < 6.3 … 10 < 10 … 16 < 16 … 25 < 25 … 40 < 40 … 63 < 63 … 100 < 100 … 160 < 160 TOLERANCE for fabric-free diaphragms with fabric and/or a metal part [mm] ±0.15 ±0.20 ±0.20 ±0.25 ±0.35 ±0.40 ±0.50 ±0.70 ±0.5% [mm] ±0.25 ±0.30 ±0.40 ±0.50 ±0.60 ±0.80 ±1.00 ±1.30 ±0.8% Tab. 51 Diameter tolerances for molded diaphragms Tolerances that are closer than those pre- viously stated can be agreed upon, if nec- essary, depending on the form and materi- al of the desired diaphragms and after performing the respective production trials. Such agreements, which typically involve increased production effort, should re- main limited to unavoidable special cas- es, however (also refer to the notes in DIN ISO 3302 in this regard). 792

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6. MODIFICATION AND COATING 6. Modification and Coating This section describes the process steps that can be optionally carried out to im- prove certain properties after the actual vulcanization process performed on the diaphragms. Typical examples are pre- sented below. 6.1 SURFACE TREATMENTS Depending on the application, friction reduction on the surface of diaphragms can offer advantages – e.g. to facilitate assembly or to reduce abrasion due to dynamic relative movement. The “classic” means of achieving this friction reduction is to use lubricants. Care must be taken to ensure that the lubricants used are compatible with the elastomer material of the diaphragm. Information on the media resistance of various elastomers can be found in → “9. Materials for diaphragms,” page 800. Other aspects to consider are the en- durance properties, required approvals and how to apply the lubricant in a repro- ducible manner. The RFN treatment developed by Freuden- berg Sealing Technologies provides an alternative to lubricants. This is of particu- lar interest for seals in sensitive areas such as food & beverages or medical technology. RFN treatment RFN stands for “Reduced Friction by Nanotechnology” (→ Chapter “Service – coating,” page 11). This innovative pro- cess makes it possible to modify the properties of elastomer surfaces in a tar- geted manner. The elasticity and dimen- sional stability of the seal are hereby retained. Typical disadvantages of lubri- cants such as restrictions for automatic assembly are eliminated. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 793 X E D N I

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Diaphragms The RFN treatment is media-resistant, re- duces stick-slip effects and thus ensures a long-lasting improvement of the sliding properties. As the base material is not changed, existing approvals of the base material, such as USP Class VI, FD A or EC 1935/2004, remain unaffected by RFN. the flash can normally be kept very small (0.1 mm high x 0.3 mm wide). If even this flash is too large, the flash can be reduced to a minimum by using cryogenic deflash- ing, thus optimizing the appearance of the parts. An example of this is shown in → Fig. 368. 6.2 CRYOGENIC DEFLASHING In the case of pure elastomer diaphragms, it is possible to remove fine flash in a downstream process. Cryogenic deflash- ing – also called ice deburring – is used for this purpose. Flash occurs, for example, in compression molding due to the parting line in the mold. In the case of pure elastomer diaphragms, before after Fig. 368 Example of cryogenic deflashing of diaphragms 794

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7. INSTALLATION 7. Installation I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I Pumps, valves, accumulators, etc. are often designed in such a way that not only initial installation of the diaphragm can be carried out in the factory, but replacement at the later place of use is also possible. In both cases, it is important that proper instructions for installation be drawn up for workers, fitters, end users, etc. In this way, the risk of installation errors affect- ing the service life of the diaphragm can be minimized. Some errors can be avoid- ed from the outset through targeted component design. Practical tips as well as typical errors during installation are described in this section. 7.1 INSTALLATION PREPARATION During installation diaphragms, make sure that the entire sealing surface is free from damage and sharp edges. Any dirt or coarse particles must be removed. If the bead does not form correctly (espe- cially in the case of rolling diaphragms), simple tubular mounting sleeves can be used, as shown in → “Fitting and installa- tion,” page 773. D o not use sharp-edged tools such as screwdrivers or similar. If necessary, the proper lubricants can be used to facilitate installation. Ideally, these should be applied immediately before or during installation. The media resistance of the diaphragm material needs to be taken into account here. 7.2 SPECIAL FEATURES IN THE CLAMPING AREA The compression height in the clamping area is key to the sealing effect of the diaphragm. An axial compression of 20 to 30% is ideal, as described in → section “5.4 Design of the clamping and housing parts in contact,” page 790. If the com- pression height is too low, there is a risk of leakage. But too much compression is also damaging. Since elastomers are almost incompressible, the volume of the com- pression gives way and can thus enter the moving area of the diaphragm (→ Fig. 369). The excess material impedes the roll-off movement of the diaphragm and can also cause friction with the diaphragm wall on the piston side if the roll gap is narrow. This can trigger premature failure. Fig. 369 Example of too much compression A mechanical stop in the housing is a con- structive means of ensuring the correct compression height regardless of the tightening torque. Due to the manufac- turing-related thickness tolerances (→ section “5.5 Dimensional tolerances of diaphragms,” page 791), a circular or semicircular sealing bead is recommended here instead of a flat seal. R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Map-marker-edit Lubricants as an installation aid S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 795 X E D N I

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7.3 SPECIAL CASE: FABRIC-REINFORCED DIAPHRAGMS When installing diaphragms with fabric cover, make sure that the fabric side is facing away from the pressure. Only then can the fabric provide its supporting ef- fect. If the side of the fabric is difficult to recognize due to significant rubber em- bedding, the fabric side can usually be de- termined tactilely (colloquially known as the “fingernail or pencil test”). Here, the surfaces on both sides of the membrane are examined. The structure of the fabric in the rubber can be felt on the fabric side Diaphragms with fabric inserts can be pressurized from both sides. However, here too, care must be taken to ensure correct positioning of the diaphragm dur- ing installation. General information on the use of fabrics in diaphragms can be found in → section “5. Design/Dimensioning,” page 786. Diaphragms 796

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8. Damage Analysis for Diaphragms 8. DAMAGE ANALYSIS FOR DIAPHRAGMS 8.2 PROCEDURE IN CASE OF COMPLAINTS As for 8.1, however the tests are carried out by an accredited laboratory. In this way, one can avoid having damage masked/reinforced by external influences, e.g. frequent bending of a component, cross-contamination. In addition, the manufacturing process including mate- rial production (rubber) is considered. The defined processes of the current complaint management system, which is based on the respective valid quality management system – currently in ac- cordance with IATF 16949 Certification (status 2021) – always serves as the basis for this. General damage analysis in accordance with VDI 3822 Since diaphragms are mainly customer- specific items, the damage analysis is car- ried out according to the application. First and foremost, the mechanical loads in the installed condition and the media at- tack are examined. In the course of dam- age analysis, a distinction is made as to whether it is an assessment within the scope of technical support (in-house) or processing of a complaint (accredited testing institute). 8.1 PROCEDURE FOR TECHNICAL SUPPORT A visual inspection of the component is carried out, including photographic docu- mentation of e.g. crack patterns, chipping, etc. compared to a new part. As far as possible, the dimensions and material properties of the components are meas- ured and differences documented. Visible damage is then assessed with re- gard to mechanical effects and/or aging phenomena. The basis for this is, among other things, VD I Guideline 3822 with the associated supplementary sheets. If further analyses are required, these can be ar- ranged in internal or external laboratories (possibly at a charge). Furthermore, it is possible to carry out simulations with a digital twin or even to perform a damage adjustment on one of the FST test benches. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 797 X E D N I

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Diaphragms 8.3 TYPICAL FAILURE PATTERNS FOR DIAPHRAGMS Swelling due to media attack Convoluted diaphragm with a fabric insert Material: EPD M with Nomex fabric Cause: Swelling of EPD M due to mineral oils/lubri- cants Rolling diaphragm with fabric support Material: NBR with polyester fabric Cause: Insufficient pressure gradient to form the roll fold or incorrect installation with formation of folds Diaphragm designation: Test probe Ø85 with compressed installation Material: EPD M with a center layer made of fabric Cause: Compressive loading as a result of the differential pressure leads to tensile stress in the radial or axial direction. The cracks are therefore oriented in the circumfer- ential direction Convoluted diaphragm swollen Fabric has been abraded/destroyed Abraded rolling diaphragm Abraded rolling diaphragm (detail) Fabric fails due to excessive pressure load P R S Crack tangential in circumferential direction Stress due to differential pressure 798

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8. Damage Analysis for Diaphragms Excessive circumferential elongation Radial crack (material: EPDM) Diaphragm with a radial crack (material: VMQ) Dg DK Elongation due to rolling motion Locally peeled rubber Abraded diaphragm Abraded diaphragm (Detail) Flat diaphragm Ø85 with a fabric insert in compressed installation Material: EPD M (left)/VMQ (right) with a middle layer made of fabric Cause: Diameter change due to up and down movement of the piston leads to tensile elongation and tensile stress in the cir- cumferential direction. The cracks are therefore radially oriented Rolling diaphragm with fabric support: Actuator on a turbo charger Material: 60 VMQ 178934 Cause: The diaphragm is mount- ed incorrectly/slanted. The rubber is rubbed off by local friction on the housing I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 799 X E D N I

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Diaphragms 9. MATERIALS FOR DIAPHRAGMS 9.1 ELASTOMERS Depending on the application, various ma- terials can be put to use. Thus, the materi- al configuration of the elastomer to be used is contingent upon the physical, thermal and chemical load stresses, for example. Additional fabric reinforcement is also foreseen for higher loads. Depending on the type of pressure applied – unilateral or bilateral – and the shape of the dia- phragm to be produced, it is designed to have a fabric insert or a support. When selecting the appropriate elasto- mer properties, the following character- istics stand in the foreground: FST Resistance Tools y for secure sealing of the clamping areas, the material should have a low-pressure release value in long-term tests y the material should be sufficiently firm for the respective load stress, elastic, flexible, resilient, chemically resistant, gas proof and abrasion resistant y material fatigue must not occur under dynamic loading y with regard to the manufacturing quality, good viscoelasticity, favorable vulcanization aspects and high adhe- siveness to potential metal or fabric inserts are demanded of the material. y low gas permeation values and good media resistance in combination with good flexibility when cold are neces- sary as material characteristics for ac- cumulator diaphragms For general material information see → chapter “Materials and process engineer- ing – 3. General material selection and descriptions”, page 48. Glass transition area Glass temperature ‒38 °C 1.E+04 1.E+03 |E*| ] a P M [ | * E | 1.E+02 1.E+01 1.E+00 tan delta 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 a t l e d n a t ‒100 ‒80 ‒60 ‒40 ‒20 0 +20 +40 +60 +80 +100 Fig. 370 DMA of a rubber compound (DMA measurement [75 Shore A EPDM material]) Temperature [°C] 800

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9. Materials for Diaphragms FFKM – Perfluoro rubber (Simriz®) Material with rubber-elastic properties that is very similar to PTFE in terms of media resistance and thermal stability. This cost-intensive material is used wherever stringent safety standards apply and very good chemical resistance is required, e.g. in valves and diaphragm pumps. The temperature range is approx. –15 °C to +230 °C Map-Marker-Exclamation Hardening of the materials due to crystallization I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Cold behaviour S L A E S C I T A T S N d 2 m m l G s u u d o m r a e h S 104 5 103 5 102 5 101 5 1 4 3 2 1 G D ‒120 ‒80 ‒40 0 0 +40 +80 +120 +160 °C D t n e m e r c e d i g n p m a d . g o L G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 371 Cold behavior 801 X E D N I IMPORTANT: Under lower temperature operating con- ditions, crystallization processes lead to a hardening of the materials. This caus- es a raising of the modulus (see the char- acteristic curve G, →Fig. 371). The materi- al thereby transforms from an elastic state to a stiff, inelastic state. The crystal- lization transition point is stated as the Tü value here. The effect of hardening can also occur in membranes depending on the frequency that the component is op- erated at. A high frequency corresponds to a low temperature. This behavior must be taken into account when selecting materials and designing components. 9.2 TYPICAL ELASTOMERS FOR DIAPHRAGMS CIIR – Chlorobutyl rubber Used particularly for gas-tight accumulator diaphragms. The preferred hydraulic me- dium is brake fluid (DOT 4). ECO – Epichlorhydrine rubber Is used in pressure accumulator dia- phragms to meet special demands with regard to gas tightness, resistance to oil and flexibility when cold. The tempera- ture range is approx. –40 °C to +140 °C. EPDM – Ethylene-propylene-diene rubber Is a common diaphragm material used with cold and warm water, hot water and steam up to 130/140 °C. KTW (potable water) certifications, WRC and FD A ap- proval. Special qualities are available for use in the foodstuffs industry.

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Diaphragms Types with a higher acrylonitrile content are used if sealing against natural gas, propane and all oils based on mineral oil are desired. For better resistance against swelling and gas proofness, poorer cold temperature characteristics must be ac- cepted as a trade-off. VMQ – Silicone rubber Used for high thermal stress from –60 °C to +200 °C. Certain compound settings are physiologically indifferent and can be sterilized with hot air, therefore VMQ is suited for use in the food industry and medical technology. FKM – Fluoro elastomer rubber FKM is the preferred material for the di- aphragms used in vacuum technology as well as with gases and fluids with a high aromatic level (“super fuels”). The temper- ature range is approx. –25 °C to +200 °C. FVMQ – Fluoro silicone rubber Is used to meet special requirements with regard to fuel resistance under cold temperatures, very often in combination with fabric reinforcement. The tempera- ture range is approx. –65 °C to +200 °C. HNBR – Hydrogenated acrylonitrile- butadiene rubber Has a higher resistance to heat and phys- ical strength with less abrasion than NBR. The higher dynamic load capacity of HNBR is used when applied in pump diaphragms. The temperature range is approx. –30 °C to +140 °C. NBR – Acrylonitrile-butadiene rubber This is the standard material for all dia- phragms pressurized with compressed air and mineral oils. Thermal applications [°C] Mineral oil resistance (volume change [%]) –100 –50 0 +50 +100 +150 +200 +250 +300 [°C] 0 5 10 15 20 25 30 [%] –50 –40 –25 –40 –30 –40 –60 –65 120 140 140 150 200 250 100 110 140 150 120 130 200 200 240 230 EPDM ECO FKM CIIR HNBR NBR VMQ FVMQ 3 0,5 2 2 0,5 8 8 15 20 excellent good not suitable Fig. 372 Material properties 802

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9. Materials for Diaphragms Typical elastomers for diaphragms Media to be sealed including information on the permanent temperature in °C s n i f e l o a h p l a y l o p ) G A P ( s l o c y l g e n e l y k l a y l o p . g e . * s t n a c i r b u l . c i t e h t n y S i o t g n d r o c c a s d u i l f e r u s s e r p e l b a d a r g e d o B i I * 9 6 5 4 2 N D d n a 8 6 5 4 2 A M D V D G F F F F F B B B D Ä G G G G G F F F l e s e i d / l i o l e u F D G D D D D D B B C * * ) C ° ( e g n a r e r u t a - r e p m e t r e w o L −35 −40 −40 −40 L A I R E T A M 0 0 0 2 D M T S A 60 CIIR 172153 60 ECO 217466 70 EPDM 216434 70 EPDM 217937 – – – – 70 EPDM 281 M 4 CA 714 –40 70 EPDM 335 60 EPDM 334 60 FKM 255256 65 FKM 217070 – – – – −40 −40 −40 −30 70 FKM 576 M 2 HK 710 −20 * a i d e m d e s a b - l i o l a r e n M i D B D D D D D B B B 75 FKM 153740 M 2 HK 810 −25 +150 +150 +80 +150 60 FVMQ 565 M 2 FE 606 −60 +150 F F +150 60 HNBR 9953 – −30 +120 +100 +80 70 HNBR 150531 M 2 DH 710 −20 +120 +100 +80 B B Other media* 4 T O D / 3 T O D d u i l f e k a r B ) B M A F / A M A F ( s l e u F D G D D D D D B B C C D C C B D F F F F F F F G G B G G l n o i t u o s t n e g r e t e D G G r e t a W G G S E T O N permeation- reduced permeation- reduced r i A +100 +130 +150 +130 +150 USP Cl. 6 +120 +120 +150 Food +150 +130 +150 +120 +100 +150 Drinking water +120 +100 +150 Drinking water cold flexible, without metal oxides H H H H C C H +200 H +200 H +200 H +200 C C +175 +130 +120 +120 +130 ) C ° 5 8 + ( ® e u B d A l G G F F B F F H H G G F C B I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 803 X E D N I

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Diaphragms Typical elastomers for diaphragms Media to be sealed including information on the permanent temperature in °C Other media* s n i f e l o a h p l a y l o p ) G A P ( s l o c y l g e n e l y k l a y l * s t n a c i r b u l . c i t e h t n y S o p . g e . * * ) C ° ( e g n a r e r u t a - r e p m e t r e w o L * a i d e m d e s a b - l i o l a r e n M i L A I R E T A M 0 0 0 2 D M T S A i o t g n d r o c c a s d u i l f e r u s s e r p e l b a d a r g e d o B i I * 9 6 5 4 2 N D d n a 8 6 5 4 2 A M D V ) B M A F / A M A F ( s l e u F l e s e i d / l i o l e u F 4 T O D / 3 T O D d u i l f e k a r B l n o i t u o s t n e g r e t e D r e t a W S E T O N r i A +100 +90 +100 C C G C C G +90 +80 +100 +100 +90 +100 +100 +90 +100 B H B B B H B B +180 +230 +200 +180 cold flexible permeation- reduced highest chemical resistance Food ) C ° 5 8 + ( ® e u B d A l G G G G G G B H B B 50 NBR 153750 – −20 +100 +80 +80 +60 50 NBR 216214 M 5 BG 510 −40 +80 50 NBR 216289 – −60 C F F G G C C 50 NBR 842 M 2 BG 514 −30 +100 +80 +80 +80 60 NBR 181 M 5 BG 607 –20 +100 +80 +80 +80 60 NBR 215928 58 PVMQ 534 70 Simriz® 491 60 VMQ 117117 – – – – 60 VMQ 571 M 5 GE 605 −50 −20 B +80 +80 +80 −100 G G B G G G B G G G B G G −10 −50 B G G D D D D D D D B D D G G G G G G D B D D * Application limits specified by the medium ** only for static use; an additional test is required for dynamic use F = no data available, probably suited, check before use. Consultation required G = no data available, probably not suited. Consultation required H = special mix design required. Consultation required B = low or no attack C = weak to moderate attack D = strong attack to complete destruction 804

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9. Materials for Diaphragms 9.3 DIAPHRAGM FABRICS In order to prevent the tearing of a pure rubber diaphragm in certain pressure ranges, strengthening elements are used for reinforcement (→ “Diaphragms with fabric reinforcement,” page 782). Three main types are used: woven, knitted and warp-knitted fabrics. Woven Knitted Warp-knitted The weaving structure leads to different properties of the final product. A distinction is still made between fabric layers and fabric inserts. The choice of the type of weaving and application depends on the application and the form of the di- aphragms. Our product developers would be pleased to support you in designing the proper product concept for your dia- phragms. In principle, there are three different material groups available for diaphragm applications: y polyester y polyamide y aromatic polyamide Polyester fabric Polyester fabrics are already characterized by good strength values with thin fabric thicknesses. They can therefore be woven relatively broadly. This benefits the deep drawing quality. The material disinte- grates completely as a result of saponifi- cation in hot water above +100 °C. Polyamide fabric Polyamide fabrics provide for a better binding of rubber and fabric than poly- ester fabrics. This is important, particu- larly for diaphragms with high stress loads and special service life require- ments. A progressive decline in strength must be anticipated with increasing operating temperatures. A certain disad- vantage is presented by the relatively thick fabric thicknesses as well as the deep drawing quality, so that manufac- turing-compatibility aspects can limit the applicability. Aramid fabric Aramid fabric (made of aromatic polyamide) loses strength only slowly even in hot water with increasing temperature and is there- fore, in combination with EPD M rubber, the proper material for fabric membranes in the hot water sector. 9.4 FOILS MADE OF PTFE A pure rubber diaphragm – with the ex- ception of a diaphragm made of Simriz® – has the disadvantage (as explained in → “Diaphragms with supports made of PTFE,” page 782) that it does not remain resistant to aggressive substances over a longer period of time. A protective foil, usually made of PTFE, is used as an aid. A wide variety of PTFE grades are used to give the composite diaphragm a specific characteristic to meet the requirements. Some special features are worth men- tioning: y electrically conductive foil y particularly flex-fatigue resistant foil I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 805 X E D N I

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Diaphragms Upon request, we can use other foils in applications as well, providing that they endure the load stresses of the vulcani- zation process. Adhesive agents are used in order that these parts adhere properly to the product. FST Chemietechnik currently has a suita- ble solution for almost all conventional rubber-metal/plastic connections. 9.5 INSERT PARTS Insert parts are considered to be those of any type of material that is vulcanized into the diaphragm. The spectrum ranges from simple metals through to modern synthetics. These “inserts” perform various functions. For instance, they convey linear shaft force to the diaphragm or stiffen it at the desired location. CODE MAXIMUM TENSILE FORCE AT +20 °C [N/mm] FABRIC THICKNESS DEEP DRAWING [mm] QUALITY POLYESTER WOVEN 85 86 87 88 POLYAMIDE WOVEN 29 31 32 57 143 806 ≥ 25.0 ≥ 20.0 ≥ 11.0 ≥ 7.0 ≥ 29.0 ≥ 110.0 ≥ 60.0 ≥ 33.0 ≥ 56.0 0.27 0.27 0.17 0.12 0.7 0.6 0.38 0.32 0.4 good good good medium limited limited medium good limited

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9. Materials for Diaphragms I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A CODE MAXIMUM TENSILE FORCE AT +20 °C [N/mm] FABRIC THICKNESS DEEP DRAWING [mm] QUALITY ARAMID WOVEN (NOMEX) 34 36 61 72 ≥ 27.0 ≥ 40.0 ≥ 14.0 ≥ 9.0 POLYESTER KNITTED/WARP-KNITTED 2 4 ARAMID KNITTED/WARP-KNITTED 1 11 ≥ 12.0 1) ≥ 3.2 1) ≥ 2.8 ≥ 4.9 0.4 0.6 0.3 0.3 0.5 0.4 0.4 0.6 limited limited medium good good good good good 1) Values apply in the direction of the rod; not measurable in the machine direction due to the formation of snags Tab. 52 Woven and knitted materials for diaphragms R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 807 X E D N I

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Diaphragms 10. TESTING AND VALIDATION OF DIAPHRAGMS POSSIBLE TESTS AND TASKS Here, the following tests and tasks, among others, can be carried out (pos- sibly subject to a charge): y Validation and verification of dia- phragms according to customer specifications y Lifetime tests in the corresponding customer units y Heat and cold tests in climatic cham- bers from –50 °C to over +200 °C y Measurement of inherent resistance and hysteresis in customer units y Construction of specific test bench- es depending on the task y Tests with various media such as steam, oils, water and compressed air y And many more Freudenberg Technology Innovation SE & Co. KG is a partner in developing new, and optimizing existing, materials and process- es. The ISO 9001-certified unit offers relat- ed development services, draws on many years of materials expertise in the fields of elastomers, polyurethanes, thermo- plastic elastomers and thermoplastics, and thus supports the innovation perfor- mance of Freudenberg’s various Business Groups. Furthermore, FST works closely with exter- nal testing institutes, e.g. for applications in the drinking water sector. Thus, all con- ceivable tests – as far as they are feasible, reasonable and necessary for the respec- tive development – can be carried out. In addition, extensive testing facilities are available at the Lead Center for Dia- phragms for the validation and verification of customer-specific components. We would be happy to work with you to develop appropriate solutions and testing options. 808

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11. SYMBOLS USED 11. Symbols used TERM CODE SYMBOL Rolling fold span Housing diameter Piston diameter Mean diameter Effective diameter Modulus of elasticity Elongation Distension due to pressure differ- ential Circumferential elongation due to uncoiling movement Linear shaft force, regulating power Force in the diaphragm wall as a result of pressure load Mold release depth, upthrow Absolute stroke travel Stroke portion above the clamping Stroke portion below the clamping Max. stroke Max. stroke portion above the clamping Max. stroke proportion below the clamping Pressure differential Radius of the curve of the rolling convolution Transitional radius in the clamping area b Dg Dk Dm Dw E ε εp εu F Fp h Hg Ho Hu Hmax Ho max Hu max p R ρ UNIT mm mm mm mm mm N/mm2 – – – N N mm mm mm mm mm mm mm N/mm2 mm mm I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 809 X E D N I

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Diaphragms TERM CODE SYMBOL Wall thickness in the flexed zone Elastomer hardness Tension Tensile stress from the pressure differential Force in the diaphragm wall per circumference length Tensile strength of the fabric Temperature Volumetric displacement Effective area Accumulator module Dissipation factor Tab. 53 Overview table of the symbols s SH σ σp σ' σ'B T V Aw E' tan δ UNIT mm S hore A N/mm2 N/mm2 N/mm N/mm °C mm3 mm2 N/mm2 – 810

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S T U F F I N G B O X P A C K N G S I 8 1 1 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS S t u ffi n g B o x P a c k i n g s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Stuﬃng Box Packings TABLE OF CONTENTS 1. PRODUCT OVERVIEW 2. HOW STUFFING BOX PACKINGS ARE USED 2.1 General 2.2 Features 3. PRODUCTS AND APPLICATIONS 3.1 Application Range 3.2 Pre-selection from the Standard Range 3.3 Standardization Proposals 4. SEALING MECHANISM AND CONSTRUCTION 4.1 Sealing Mechanism 4.2 Construction 5. EXAMPLES OF USE 6. DIFFERENT TYPES OF BRAIDING MATERIALS FOR STUFFING BOX PACKINGS 7.1 General 7.2 7.3 Organic natural fibers Organic synthetic fibers PTFE Yarns PTFE Graphite Yarns Aramid fibers Acrylic fibers Polyacryllonitrile (PAN) Yarns Inorganic synthetic fibers Carbon Yarns Graphite Yarns Glass fibers Silicate Yarns Impregnation and Lubrication products 7.4 7.5 7. 812 814 828 828 828 830 830 831 833 837 837 838 839 841 842 842 842 842 842 842 843 843 843 843 843 844 844 844 845

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Table of Contents 8. STANDARDS FOR THE REDUCTION OF FUGITIVE EMISSIONS ISO 15848 TA-Luft Clean Air Act API 622 API 624 9. MEDIA TO BE SEALED 9.1 Media Table 9.2 Media Register of Stuffing Box Packings 10. HANDLING AND INSTALLATION OF STUFFING BOX PACKINGS 10.1 General 10.2 Pre-Compression of Packing 10.3 Installation of Molded rings 10.4 Tolerances and surfaces 10.5 Gap widths 10.6 Storage 11. EQUIPMENT FOR DISASSEMBLY AND CUTTING OF PACKINGS 11.1 Merkel® Packing Extractor 7500 11.2 Merkel® Ring Segments 7511 11.3 Merkel® Packing Cutting Gauge 7505 12. TROUBLESHOOTING 12.1 General 12.2 Installation 12.3 Extrusion 1 12.4 Extrusion 2 12.5 Shaft balancing 12.6 Axial Deformation of the Packing 12.7 Shaft runout 846 846 846 846 846 846 848 848 850 855 855 855 856 856 856 856 857 857 857 857 859 859 859 859 860 861 861 861 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 813 X E D N I

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Stuﬃng Box Packings 1. PRODUCT OVERVIEW DESIGN DESCRIPTION PRODUCT GROUP Packages standard Merkel® Ramilon 4586 Merkel® Ramilon 4586 is braided from ramie yarn, an extremely wear- and water-resistant natural fiber yarn. The packing contains a high degree of PTFE due to a multi-impregnation process. This guarantees a high cross-sectional density and low frictional values Merkel® Arostat 6204 Merkel® Arolan II 6215 Merkel® Arochem S 6216 Merkel® Unistat 6303 Merkel® Arostat 6204 is manufactured from a wear- resistant and flexible aramid yarn. The packing has a multi-stage PTFE impregnation. This results in a very tight and elastic structure which makes Merkel® Arostat ideal for static covers and housing seals Merkel® Arolan II 6215 consists of highly wear-resistant aramid yarn as well as a special PTFE impregnation and a universally stable running-in lubricant. The high wear resistance paired with a broad thermal and chemical operating range makes Merkel® Arolan II a universal packing for many branches of industry Merkel® Arochem S 6216 combines the advantages of two highly developed yarn materials for the sealing of high-speed shafts. The special running properties of thermally-resistant PTFE-graphite compound yarns guarantee shaft protection and allow for brief dry run- ning without damage. The wear-resistant aramid yarn edges prevent extrusion and protect against abrasive media. Merkel® Arochem S contains a universally stable silicone-free running-in lubricant. This ensures sufficient lubrication during the critical running-in phase Merkel® Unistat 6303 is braided from a graphite-filled PTFE yarn. The high graphite content ensures good heat dissipation and the PTFE material ensures excellent friction behavior. The dense and pressure-resistant structure makes the packing especially well-suited for plunger pump applications. Due to its chemical resist- ance, Merkel® Unistat 6303 is universally suited for applications in the chemical industry 814

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE Merkel® Ramilon is also used in plunger pumps for high pressure water applica- tions. The packing materials are approved for use in the food processing industry. Rotary pumps, refiners, mills, plunger pumps, stern tube applications Valves; housings Rotary pumps; valves Rotary pumps; plunger pumps Ramie with PTFE impregna- tion Meta-aramid yarn and multiple PTFE impregnation Para-aramid yarn and special PTFE impregna- tion PTFE graphite compound yarn and aramid yarns on the edges ‒40 … +120 Yes Further information on our product portfolio ‒50 … +250 Yes ‒50 … +280 Yes ‒50 … +280 Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B The packing material is approved for use in the food processing industry Graphite-filled PTFE yarn ‒200 … +280 Yes S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 815 X E D N I

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Stuﬃng Box Packings DESIGN DESCRIPTION Merkel® Unichem 6313 Merkel® Unival 6323 Merkel® Alchem 6375 Merkel® Unichem 6313 is braided from pure PTFE yarns and impregnated with a running-in lubricant. The packing has a very dense structure and is yet soft and flexible. Sealing can be achieved with a minimum amount of gland pressure. Merkel® Unichem features very good friction behavior Merkel® Unival 6323 consists of graphite-filled, oiled PTFE yarn. Due to a special braid structure, the advan- tages that this material offers (low thermal expansion and excellent heat conduction) are optimally exploited. Merkel® Unival is a very flexible packing and seals relia- bly with a minimum of gland pressure, even against thin liquid media that have a tendency to creep. It can also withstand dry friction up to a certain limit Merkel® Alchem 6375 is made from pure PTFE yarns and is additionally impregnated with PTFE. This guarantees excellent chemical resistance. The high cross-sectional density and the tight braid structure ensure very good sealing behavior. The packing has good form stability and low shrinkage behavior Merkel® Grafiflex 6501 Merkel® Grafiflex 6501 is characterized by the highest chemical and temperature resistance as well as the best sealing effect and permanent elasticity. Even after temperature cycles, there is no cold flow, shrinkage or aging of the material PRODUCT GROUP Standard packings 816

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE The packing is approved for use in the food industry. Merkel® Unichem is also available as a flat strip for static sealing. Rotary pumps in the process industry (e.g. chemical, food) Pure PTFE yarn impregnated with running-in lubricant ‒100 … +250 Yes Rotary pumps; valves Graphite-filled PTFE yarn ‒100 … +280 Yes The packing is approved for use in the food industry. Plunger pumps; valves Pure PTFE yarn with PTFE impregnation ‒200 … +280 Yes The packing is approved for use in the food industry (version 6501 additionally suitable for drinking water/ KTW compliant). Fittings in hot water, feed water, steam, heat transfer oils, hydrocarbons and many other media. For gaseous oxygen (43 MPa up to +60 °C; 16 MPa up to +200 °C), BAM tested. Cover gaskets Molded graph- ite rings with density from 1.4 to 1.85 g/cm3 ‒200 … +450; ‒200 … +700 (Steam range) Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 817 X E D N I

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Stuﬃng Box Packings DESIGN DESCRIPTION Merkel® Carbosteam 6550 Merkel® G-Spezial 6560 Merkel® G-Spezial S 6565 Merkel® Uniflex 6588 Merkel® Carbosteam 6550 is braided from flexible carbon yarns with a special graphite impregnation. Due to its excellent temperature stability, the packing is especially used in high-temperature steam applications. Due to its high pressure and extrusion resistance, Merkel® Carbosteam is ideal as an end ring in conjunction with Merkel® Grafiflex Merkel® G Spezial 6560 is made of temperature resist- ant, flexible braided graphite yarns each of which is reinforced with a very thin Inconel wire. This highly pressure-resistant braided packing has the same excellent sealing effect as pure graphite rings wound from strip material. For gaps greater than 0.2 mm, the use of Merkel® Carbosteam 6550 is recommended as extrusion protection. Also available as G-Spezial S 6569 with a corrosion inhibitor Merkel® G -Spezial S 6565 is braided from pure, ex- panded graphite yarns. The packing combines all the advantages of the expanded graphite such as high temperature stability and high cross-sectional density. The rings made from Merkel® G-Spezial S can simply be cut from the roll for application cases where quick repair is required. Can be used in combination with end rings from Merkel® Carbosteam 6550 for high-pressure valve applications Merkel® Uniflex 6588 is manufactured from a special flexible yarn with a high carbon content and a PTFE- graphite impregnation as well as a running-in lubricant. The packing is very flexible and extrusion-resistant. The impregnation maintains an excellent bond to the braid over the complete life of the packing. The good temperature and volume stability of the packing provides superior sealing behavior even with minimal gland pressures. Thus, Merkel® Uniflex can sometimes also be used for dry running PRODUCT GROUP Standard packings 818

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE Valves in hot water; steam; acids and alkalis Carbon yarn with a special graphite im- pregnation ‒30 … +400; ‒30 … +550 (Steam range) Merkel® G-Spezial is espe- cially suited for quick repair services. Valves in hot water; steam; gases; oils; acids and alkalis Pure graphite yarn with inconel wire reinforcement ‒200 … +450; ‒200 … +650 (Steam range) Valves; rotary pumps Pure graphite yarn ‒200 … +450; ‒200 … +650 (Steam range) Yes Yes Yes Rotary pumps in cold and hot water; steam; aqueous solutions; diluted acids and alkalis Special yarn with high carbon content and PTFE graph- ite impregna- tion ‒50 … +280 Yes I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 819 X E D N I

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Stuﬃng Box Packings DESIGN DESCRIPTION Merkel® Kombilon 6742 Merkel® Univerdit 7000 Merkel® Kombilon 6742 consists of an elastic combi- nation braid made from carbon and PTFE yarns. The packing is impregnated with a special PTFE compound and running-in lubricant. The specific composition of Merkel® Kombilon ensures very low frictional forces and high elasticity. The packing maintains its elasticity even after prolonged operation and under high contact pressure. The specially processed carbon yarn is very flexible and protects the shaft particularly well Merkel® Univerdit 7000 is a compact, extruded packing made of PTFE graphite compound. It offers maximum gas tightness and is able to absorb abrasive particles. Univerdit remains self-lubricating even during extend- ed periods of operation and protects the shaft and spindle. Merkel® Univerdit must always be installed with end rings Merkel® Valtec 6350 Merkel® Valtec 6350 has a carbon fiber core and is concentrically overbraided with a dense PTFE fiber fabric. In addition, it contains a special impregnation to improve the cross-sectional density of the packing Merkel® Valtec 6559 Merkel® Valtec 6559 is a specially developed packing consisting of high-purity expanded graphite material (C-content > 98%). It is overknitted by Inconel wire fabric with a special high-temperature impregnation and a corrosion inhibitor Merkel® Valtec 7200 Merkel® Valtec 7200 is a packing ring made of impreg- nated nonwoven materials that guarantees excellent sealing performance. The ring consists of nonwoven meta-aramid fibers with a very dense PTFE impregnation PRODUCT GROUP Standard packings Packings for fugitive emissions 820

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A The packing is approved for use in the food industry. Rotary pumps; mixers and agitators Carbon and PTFE yarns and im- pregnated with a special PTFE compound and running-in lubri- cant R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H ‒100 … +280 Yes R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Rotary pumps; valves PTFE graphite compound ‒30 … +250 Yes Control valves for require- ments according to TA-Luft and ISO 15848 Carbon fibers and PTFE ‒100 … +280 Yes High-temperature packing for requirements according to TA-Luft, ISO 15848, API 622, API 589 (Fire Safe), Chevron and Texaco Test High purity ex- panded graphite material and Inconel ‒200 … +450; ‒200 … +650 (Steam range) Yes Control valve fittings for requirements according to TA-Luft, ISO 15848 – all chemicals (solvents; hydro- carbons; alkalis; acids). Exceptions: highly concen- trated acids and alkalis; fluorine and some fluorine compounds Meta-aramid nonwoven fibers with PTFE impregnation ‒200 … +280 Yes S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 821 X E D N I

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Stuﬃng Box Packings DESIGN DESCRIPTION Merkel® Valtec 7250 Merkel® Valtec 7250 is a packing set made of impreg- nated nonwoven materials that guarantees excellent sealing behavior. Two end rings made of nonwoven carbon fibers are impregnated with PTFE/graphite. The center rings are made of nonwoven aramid fibers with very dense PTFE impregnation Merkel® Valtec 7290 Merkel® Valtec 7290 consists of braided expanded graphite end rings with carbon yarn corners, highly compressed graphite discs as permeation barriers, impregnated expanded graphite adapter rings and, in addition, a specially impregnated and friction- optimized expanded graphite sealing ring Merkel® Valtec 7300 Merkel® Valtec 7300 is a specially developed packing ring set made of laminated nonwoven carbon fibers and expanded graphite material with special high-temperature impregnation. The ring components are closed or endless Merkel® Ramiflex 4510 Merkel® Ramiflex 4510 is braided from very stable, flexible and wear-resistant yarn and impregnated with a bright red special grease. Ramie is many times more wear-resistant than cotton and rot-resistant Merkel® Arolan 6210 Merkel® Arolan 6210 consists of wear-resistant aramid yarn with PTFE impregnation and running-in lubricant. The packing has already proven itself in a wide variety of applications. Especially where hardening, crystallizing or abrasive media can have a damaging effect on the packing, Arolan offers long-lasting resistance PRODUCT GROUP Packings for fugitive emissions Special packings 822

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A Control valves for require- ments according to TA-Luft, ISO 15848 – all chemicals (solvents; hydrocarbons; alkalis; acids). Exceptions: highly concentrated acids and alkalis; fluorine and some fluorine compounds Nonwoven car- bon fibers with PTFE graphite impregnation. Center rings made of nonwo- ven aramid fibers with PTFE im- pregnation R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H ‒200 … +280 Yes R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P High temperature packing kit for requirements accord- ing to TA-Luft, ISO 15848, API 622, API 589 (Fire Safe. Suited for most chemicals (solvents; hydrocarbons; acids; alkalis); steam; alcohols; water; oils; etc. Universal use in all valve applications, mainly at higher temperatures, e.g. in general industry. Requirements according to TA-Luft, ISO 15848, API 589 (Fire Safe) Graphite and carbon yarn cor- ners; graphite discs ‒200 … +400; ‒200 … +550 (Steam range) Laminated non- woven carbon fibers and expanded graph- ite material ‒200 … +400; ‒200 … +550 (Steam range) Yes Yes Rotary and plunger pumps Ramie yarn ‒10 … +120 No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B Rotary and plunger pumps; refiners; paddle dryers and agitators Aramid yarn with PTFE impregnation ‒50 … +280 No S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 823 X E D N I

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Stuﬃng Box Packings DESIGN DESCRIPTION Merkel® Arochem II 6211 Merkel® Arochem II 6211 is made of PTFE-graphite compound yarn with edges reinforced by aramid yarn. The braiding makes the packing particularly stable and therefore suited for sealing plungers and slow-turning shafts. The stable aramid yarn braided into the packing edges protects against gap extrusion and is therefore used especially for difficult sealing cases, such as large gap bridges and abrasive media Merkel® Arochem 6212 Merkel® Arochem 6212 consists of PTFE yarn with edges reinforced by aramid yarn. The good sliding properties of PTFE, the high tensile strength and the extremely low tendency to gap extrusion of the stable aramid yarns are the basis for its successful use in plunger pumps Merkel® Aroflex 6226 Merkel® Aroflex 6226 consists of aramid staple fiber yarn with grease/graphite impregnation. Easy running properties and stability at high temperatures ensure high performance and a long service life Merkel® Flexalon 6250 Merkel® Flexalon 6250 is made of a white synthetic yarn with PTFE impregnation and running-in lubricant. The packing thus offers good resistance to abrasive media in contrast to PTFE products Merkel® Unival II 6326 Merkel® Unival II 6326 consists of PTFE yarn with graphite impregnation and running-in lubricant. As a very flexible packing, Unival II 6326 responds to even the lowest gland pressures and also seals reliably against low-viscosity and creeping media. The packing even tolerates dry friction within limits Merkel® Unival 6329 Merkel® Unival 6329 consists of 100% GFO® yarn. The very flexible packing responds to even the slightest gland pressures and seals reliably even against low- viscosity and creeping media. Unival 6329 even toler- ates dry friction within limits PRODUCT GROUP Special packings 824

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A Plunger pumps Plunger pumps; mixers; kneaders; soot blowers Rotary pumps PTFE-graphite compound yarn with edges re inforced by aramid yarn PTFE-yarn with edges reinforced by aramid yarn Aramid yarn with grease/ graphite impreg- nation R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H ‒50 … +280 No R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P ‒50 … +280 No ‒10 … +150 No S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P The packing is approved for use in the food sector. Rotary pumps; mixers; kneaders and refiners Meta-aramid yarn with PTFE impregnation ‒50 … +250 No Rotary pumps; mixers; kneaders; stirrers and dryers PTFE yarn with graphite impregnation ‒100 … +280 No Valves and rotary pumps PTFE yarn with graphite impregnation ‒100 … +280 No C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! 825 X E D N I

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Stuﬃng Box Packings DESIGN DESCRIPTION Merkel® Thermapack 6401 Merkel® Thermapack 6401 consists of 100% silica yarn. Impregnation with a specially developed emulsion rounds off the optimal performance of Thermapack 6401 under extreme thermal operating conditions Merkel® GC Spezial 6567 Merkel® Grafolan HT 6570 Merkel® G-Spezial AR 6562 Merkel® Carboflex 6587 Merkel® Carbosteam S 6555 Merkel® GC Spezial 6567 consists of expanded flexible graphite yarns and is reinforced by carbon yarns in the corners. The packing has excellent thermal and chemi- cal resistance as well as high elasticity. Due to the de- sign, the packing is very gentle on the shaft even at high temperatures Merkel® Grafolan HT 6570 made of graphite yarn with special high-temperature impregnation is a valve packing for the highest temperature loads in chemical applications and power generation. The special high-temperature impregnation provides the necessary cross-sectional density, improves the friction behavior and stabilizes the braid structure Merkel® G Special AR 6562 consists of expanded graph- ite yarn with reinforced corners of synthetic yarn and running-in lubricant. Good heat dissipation and temper- ature stability make the packing particularly suitable for high shaft speeds. The edge reinforcement protects the packing against abrasive media Merkel® Carboflex 6587 consists of carbon yarn with PTFE graphite impregnation and running-in lubricant. Carbo flex behaves very stable in terms of volume and is characterized by nearly universal chemical resistance. The low coefficient of expansion, a low coefficient of friction and the ability to more easily overcome the critical running-in phase prevent sudden uncontrolled heat generation at high sliding speeds Merkel® Carbosteam S 6555 consists of a flexible expanded graphite core with a specially designed wear-resistant cover made from pure carbon fibre. In ad- dition to good elasticity and high cross-sectional density, this packing exhibits permanent volume stability. The enclosing braid is dense and heat-resistant. The addi- tional graphite impregnation facilitates installation and optimizes the sliding behavior on the spindle PRODUCT GROUP Special packings 826

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1. Product Overview MAIN APPLICATIONS MATERIAL MAX. TEMPERA- TURE RANGE [°C] * STANDARD CATALOG RANGE Static applications Silica yarn ‒50 … +1.100 No Rotary pumps; valves Carbon yarn with expanded graphite yarn ‒30 … +400; ‒30 … +550 (Steam range) Valves Graphite yarn ‒30 … +400; ‒30 … +550 (Steam range) No Yes Rotary pumps Rotary pumps Expanded graphite yarn with reinforced corners made of synthetic yarn Carbon yarn with PTFE graphite im- pregnation ‒100 … +280 No ‒30 … +300 No Valves in power generation Expanded graphite core with carbon yarn braiding ‒30 … +400; ‒30 … +550 (Steam range) No * Temperature specification applies to measurement at the seal. The temperature of the operating medium can differ! I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 827 X E D N I

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Stuﬃng Box Packings 2. HOW STUFFING BOX PACKINGS ARE USED 2.1 GENERAL Stuffing box packings from Freudenberg Sealing Technologies (hereinafter also abbreviated FST) are sold on the market under the name Merkel® stuffing box packings. Merkel® stuffing box packings are manufactured to the highest quality standards, offer universal properties and have proven their value for over 100 years. The combination of tried-and-trusted material qualities in conjunction with new material developments enables FST to be able to seal a broad range of appli- cation cases reliably with only a few dif- ferent packing types. The limited stocking requirements for various packing types allows the customer to optimize costs effectively. 2.2 FEATURES Stuffed packings should have the following characteristics: y resistance to a wide range of chemicals y good thermal stability y resistance to strong mechanical stresses y abrasion resistance y high flexibility y long service life y low leakage rate Leakage control is essential for the success- ful operation of mechanical equipment used for conveying liquid and gaseous media. FST Website Stuffing box packings Product catalog 828

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2. How Stuffing Box Packingsare used Various methods are used to control leak- age from shafts, rods or spindles and other functional parts of machines containing liquids or gases. Stuffing box packings are made of rela- tively soft and flexible materials. They consist of a certain number of rings, which are inserted into the stuffing box between the casing and the rotating or reciprocating element of the pump or the fittings. Depending on the type and application, Merkel® stuffing box packings offer: y low thermal expansion with excellent heat dissipation properties y long service life y low friction y high wear-resistance against abrasive media y rot-resistance y hydrolysis-resistance y shaft-protecting natural fibers for longer service life y high pressure resistance y easy installation I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 829 X E D N I

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Stuﬃng Box Packings 3. PRODUCTS AND APPLICATIONS 3.1 APPLICATION RANGE Merkel® stuffing box packings are ideal for standard applications. They are also used in the petrochemical, pharmaceutical and chemical industries, paper industry, steel industry, as well as shipyards and water treatment plants – wherever strict legal environmental requirements have to be met for a variety of processes. Merkel® stuffing box packings seal all types of liquids over a wide range of tem- peratures and pressures, including water, steam, acids, caustics, solvents, gases, oil, hydrocarbons and other chemicals. For more information, please refer to the media table (→ “9.1 Media Table”, page 848). Applications with special conditions y Feed water pump seals for steam boilers y Cooling water pumps y Piston pumps y Spindle seals in valves y Cover gaskets y Sootblower seals up to +550 °C oper- ating temperature y Mixers y Kneaders y Autoclaves y Paddle dryers 830

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3. Products and Applications 3.2 PRE-SELECTION FROM THE STANDARD RANGE PRESSURE [MPa] SPEED [m/s] TEMPERATURE [°C] pH VALUE PRODUCTS Rotary pumps Plunger- pumps Valves Rotary pumps Plunger- pumps Merkel® Ramilon 4586 40 100* Merkel® Arostat 6204 Merkel® Arolan II 6215 2.5 Merkel® Arochem S 6216 2.5 Merkel® Unistat 6303 Merkel® Unichem 6313 Merkel® Unival 6323 Merkel® Alchem 6375 Merkel® Grafiflex 6501 Merkel® Grafiflex Cover gasket Merkel® Carbosteam 6550 Merkel® G-Special 6560 Merkel® G-Special S 6565 Merkel® Uniflex 6588 Merkel® Kombilon 6742 1.5 2.5 2.5 2.5 2.5 20 10 100 25 25 25 25* 80* 50* 100 100 30 45 25 Merkel® Univerdit 7000 2.5* 16* 13 26 25 8 20 25 25 20 6 2 2 2 2 2 –40 … +120 5 … 11 –50 … +250 1 … 13 –50 … +280 1 … 13 –50 … +280 1 … 13 –200 … +280 0 … 14 –100 … +250 0 … 14 –100 … +280 0 … 14 –200 … +280 0 … 14 –200 … +450 1) –200 … +700 2) –200 … +2.500 3) –200 … +450 1) –200 … +700 2) –200 … +2.500 3) –30 … +400 1) –30 … +550 2) –200 … +450 1) –200 … +650 2) –200 … +450 1) –200 … +650 2) 0 … 14 0 … 14 0 … 14 1 … 14 0 … 14 –50 … +280 0 … 14 –100 … +280 1 … 13 –30 … +250 0 … 14 1) most media 2) steam 3) inert gas * chambered installation I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 831 X E D N I

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Stuﬃng Box Packings PRODUCTS Merkel® Valtec 6350 Merkel® Valtec 7200 Merkel® Valtec 7250 Merkel® Valtec 7290 Merkel® Valtec 6559 Merkel® Valtec 7300 PRESSURE [MPa] Valves SPEED [m/s] Valves TEMPERATURE [°C] pH VALUE 30 25 25 30 45 25 2 2 2 2 2 2 –100 … +280 –200 … +280 –200 … +280 –200 … +400 1) –200 … +550 2) –200 … +450 1) –200 … +650 2) –200 … +400 1) –200 … +550 2) 0 … 14 0 … 14 0 … 14 0 … 14 0 … 14 0 … 14 1) most media 2) steam 832

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3. Products and Applications 3.3 STANDARDIZATION PROPOSALS These recommendations are intended to form the basis for the efficient use of stuffing box packings. For further information, please contact your local Freudenberg Sealing Technologies sales representative. PUMPS, AGITATORS ETC. VALVES INDUSTRY MEDIUM Breweries Chemical industry in general Mash Wort Water Beer Brine Alkalis Ammonia Steam Alkalis Acids, inorganic Acids, organic Crystalline media Hardening media Halogens n o l i m a R B B B B B B B m e h c o r A / n a l o r A n o l i b m o K / l a v i n U t i d r e v i n U x e l f i n U t a t s o r A t a t s i n U m e h c l A / m a e t s o b r a C l a i z e p S - G x e l f i f a r G B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B Solvents: aliphatic, aromatic and chlorinated B B B Alcohols B B B B B B suitable packing type I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 833 X E D N I

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Stuﬃng Box Packings INDUSTRY MEDIUM Chemical industry in general Esters Ketones Oils, greases Water (incl. waste) Steam Paint industry Greasing oils Solvents Dispersion paints Synthetic resin paints Power plants Boiler feed water Condensed water Cooling water River water Steam Paper industry Fibrous water Pulps Drum water Condensed water Screening water Waste water Alkalis Steam B suitable packing type 834 PUMPS, AGITATORS ETC. VALVES n o l i b m o K / l a v i n U t i d r e v i n U B B x e l f i n U B B B B B B B B B B B B B B m e h c o r A / n a l o r A B B B B B B B B n o l i m a R B B B B B B B B B B B B B B B B B / m a e t s o b r a C l a i z e p S - G x e l f i f a r G B B t a t s o r A t a t s i n U B B B B m e h c l A B B B B B B B B B B B B B B B B B B B B B B B

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3. Products and Applications PUMPS, AGITATORS ETC. VALVES I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A n o l i b m o K / l a v i n U t i d r e v i n U n o l i m a R m e h c o r A / n a l o r A B B B B INDUSTRY Refineries MEDIUM Crude oil Aliphatic hydro-carbons Aromatic hydro-carbons Chlorinated hydro-carbons Bitumen Heat transfer oils Steam Organic acids Inorganic acids Chlorine Alkalis Pulp Industry Boiler liquids: p H 1-3 Boiler liquids: p H 13-14 Chlorine dioxide Sulphatic water Hypochlorite Hydrochloric acid Fiber suspension Steam Cement industry Cement mud Water B B B suitable packing type x e l f i n U B B B B t a t s o r A B B B B B B B B B B B B B B B B B B B B B B B B B B B B B m e h c l A B B B B B B B B B t a t s i n U B B B B B B B / m a e t s o b r a C l a i z e p S - G x e l f i f a r G B B R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I B B X O B G N I F F U T S I S G N K C A P 835 X E D N I

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Stuﬃng Box Packings PUMPS, AGITATORS ETC. VALVES m e h c o r A / n a l o r A n o l i b m o K / l a v i n U n o l i m a R B B B B B t i d r e v i n U B B B B B x e l f i n U t a t s o r A B B B B B / m a e t s o b r a C l a i z e p S - G x e l f i f a r G t a t s i n U m e h c l A B B INDUSTRY MEDIUM Sugar industry Water (also with sand) Raw juice Milk of lime Skimmed froth Sugar juice, molasses Steam B suitable packing type 836

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4. Sealing Mechanism and Construction 4. SEALING MECHANISM AND CONSTRUCTION 4.1 SEALING MECHANISM A stuffing box consists of the stuffing box packing and a stuffing box gland with which the stuffing box packing is axially compressed by means of bolts or springs. In the case of elastic sealing material, axial compression also results in radial compression of the stuffing box packing on the shaft. In this way, the sealing gap can be adjusted to a minimum suitable for the operating conditions. A defined leakage may be required for pumps. In this case, the liquid and/or external lubri- cants (supplied via the lantern ring) form a lubricating film between the stuffing box packing and the shaft. Leakage I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P Medium Leakage S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P Medium Radial forces Radial forces Fig. 373 Packing before and after compression Pressure C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 837 X E D N I

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Stuﬃng Box Packings 4.2 CONSTRUCTION For a correct stuffing box design, see → Fig. 374 below. The recommended surface finish for shafts, plungers or spindles is Rz < 1.6 µm. For an improved sealing effect and longer service life, the surface finish can be reduced to Rz < 0.6 µm. For rotary pumps, the max. shaft runout should be < than 0.001 times the shaft diameter. To obtain minimal leakage for valves, the shaft runout should be less than 0.01 times the packing width. The max. gap ➄ between the shaft/spindle and the gland/housing must not exceed 2% of the packing width. If the gaps are larger or the selected packing tends to extrude, in- stall the appropriate anti-extrusion rings. 1 2 3 1 2 3 4 5 6 7 8 9 Adjustment travel for stuff- ing box 20–30% of the height of the packing set Min. insertion depth for stuffing box 0.5 x packing width Height of packing set Packing box diameter Gap max. 0.02 x packing width Shank/shaft diameter Chamfer 2 x 30° Packing width Stuffing box packing Fig. 374 Stuffing box packing technical data 838 7 8 9 4 6 5 5

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5. EXAMPLES OF USE 5. Examples of Use Basic packing arrangements are shown in these examples of use. BASIC DESIGN OF A STUFFING BOX General application for valves, centrifugal and plunger pumps. STUFFING BOX WITH VARIOUS TYPES OF PACKINGS y for chambering plastic packings, braided packings are used as anti-extrusion rings y highly pre-compressed rings for bridging large gap widths y high-density end rings as replacements for metal guides STUFFING BOX WITH A LANTERN RING y for lubrication y for sealing with overpressure y for sealing with negative pressure (leakage suction) y for cooling STUFFING BOX WITH TWO LANTERN RINGS y first ring for high-pressure lubrication, second ring for suction y sealing with different media STUFFING BOX WITH OUTER COOLING SLEEVE for shaft seals with media with operating temperatures above their boiling point I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 839 X E D N I

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Stuﬃng Box Packings STUFFING BOX WITH THE SPRING ON THE INSIDE mainly for high pressure plunger pumps (Spring force only designed for pre-sealing) SELF-SEALING SEALING COVER WITH HIGH DENSITY GRAFIFLEX RINGS y Cover Sealing y Application e.g. Bredtschneider-Udhe seals STUFFING BOX WITH THE SPRINGS ON THE OUTSIDE also called “live-loading” where a spring mechanism is fitted on the packing gland bolts to maintain load on the packing rings. The spring force must be larger than the media pressure times the ring surface area. Application: e.g. in TA-Luft-compliant valves, especially control valves. 840

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6. DIFFERENT TYPES OF BRAIDING 6. Different Types of Braiding Depending on the application and man- ufacturing process, there are different types of packing. These consist of square and diagonally braided yarns that can also be impregnated. CONCENTRIC BRAID/BRAID OVER BRAID y fine, dense surface structure y low mechanical wear resistance y rectangular or round shapes available 2-TRACK SQUARE BRAID/DOUBLE DIAGONAL BRAID rough surface, good elasticity RINGS OR RING SEGMENTS MADE OF COMPRESSED GRAPHITE FOIL OR EXPANDED GRAPHITE MATERIAL y high section density y excellent resistance to pressure, tem- perature and chemicals 3-TRACK SQUARE BRAID/CROSS BRAID y good cross section stability y dense but flexible braiding structure y nominal packing size between 5 and 12 mm 4-TRACK SQUARE BRAID/CROSS BRAID y smooth surface y very wear resistant – high cross cut stability y high density braid structure y nominal packing size between 10 and 80 mm I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 375 Mechanical braiding 841 X E D N I

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Stuﬃng Box Packings 7. MATERIALS FOR STUFFING BOX PACKINGS PTFE YARNS 7.1 GENERAL Depending on the type of stuffing box packing, the yarn used is made of differ- ent materials, such as cellulose, ramie, cotton, polyamide, aramid, PTFE with graphite, pure graphite foils, carbon, mixed yarn, and others. 7.2 ORGANIC NATURAL FIBERS y Ramie y Flax y Jute y Hemp y Cotton Advantages: y gentle on the shaft y good springback y economically attractive Disadvantages: y low temperature resistance y partial shrinkage in water (not a disad- vantage with ramie) y limited chemical resistance 7.3 ORGANIC SYNTHETIC FIBERS y PTF E Yarns (PolyTetraFluoroEthylene) y PTF E graphite yarns y Aramid fibers y Acrylic fibers y Polyacryllonitrile (PAN) Yarns Advantages: y excellent chemical resistance y smooth running due to low friction y good sealing effect y good temperature resistance Disadvantages: y poor thermal conductivity y tendency to cold flow and extrusion y packings have poor elasticity (cannot be used if shaft runs with too much de- flection) y partially limited sliding speed PTFE GRAPHITE YARNS Advantages: y excellent chemical resistance y smooth running due to low friction y very good thermal conductivity y good temperature resistance y higher sliding speeds possible y no wear on the shaft Disadvantages: y tendency to cold flow and extrusion y possible contamination of the medium with graphite particles 842

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7. Materials for Stuffing Box Packings ARAMID FIBERS POLYACRYLLONITRILE (PAN) YARNS Advantages: y excellent elasticity (suitable for sealing against shaft deflection) y excellent chemical resistance y good temperature resistance Disadvantages: y can cause shaft wear y hydrolysis tendency with steam up to +180 °C ACRYLIC FIBERS Advantages: y inexpensive y good temperature resistance y very flexible Disadvantages: limited chemical resistance 7.4 INORGANIC SYNTHETIC FIBERS y Carbon yarns y Graphite yarns y Glass fibers y Silicate yarns CARBON YARNS Advantages: y economically attractive y good abrasion resistance y flexible Disadvantages: y low tensile strength y shrinks at higher temperatures Advantages: y applicable at high temperatures y good chemical resistance (cannot be used with oxidizing media) y smooth running due to low friction Disadvantages: y poor sealing effect y poor pressure resistance I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 843 X E D N I

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Stuﬃng Box Packings GRAPHITE YARNS SILICATE YARNS Advantages: y can be used at very high temperatures y very good chemical resistance Disadvantages: y poor sealing effect y poor pressure resistance GLASS FIBERS Advantages: y very high temperature resistance (+1,100 °C) y low thermal conductivity y non-flammable Disadvantages: y poor sealing effect y poor pressure resistance Advantages: y very high temperature resistance (+550 °C) y staple fiber yarns with good flexibility Disadvantages: y poor sealing effect y poor pressure resistance 844

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7. Materials for Stuffing Box Packings 7.5 IMPREGNATION AND LUBRICATION PRODUCTS WHY IS IMPREGNATION NECESSARY? Each Merkel® stuffing box packing is de- veloped and manufactured according to a unique recipe based on structural yarns in combination with impregnations and lubricants. The specific impregnation process and the selection of lubricants contribute significantly to reducing wear to a minimum and increasing the service life of the packing. Impregnations are needed to y increase the density of the packing y reduce friction when starting up the pump y obtain a lubricant deposit in the packing y increase the chemical resistance METHODS FOR IMPREGNATING PACKINGS y impregnation of the yarn before braiding y impregnation during braiding y impregnation of the packing after braiding Impregnations and lubricants Impregnations PTFE Graphite Talcum Barium Sulphate Vaseline Greases Lubricants Wax Paraffin Silicone oil Mineral oil I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P Fig. 376 Impregnation 845 X E D N I

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Stuﬃng Box Packings 8. STANDARDS FOR THE REDUCTION OF FUGITIVE EMISSIONS Standards and directives are set by govern- ments, companies and institutions to clas- sify the properties, limitations and perfor- mance of stuffing box packings used in a range of applications that immediately and directly affect people and the environment. Merkel® stuffing box packings are ideally suited to counteract emissions of fugitive substances. Valves, especially control valves, account for approximately 60% of leakage losses in process plants with haz- ardous emissions. Conventional sealing products can be replaced with specially developed and tested “low-emission” sealing kits from Merkel®. There are various regulations for reducing fugitive emissions. These include, for ex- ample: ISO 15848 y ISO 15848-1 specifies inspection/testing procedures for leakage measurements of valves y ISO 15848-2 specifies production accept- ance testing of valves → Tab. 54 shows the graduation and the max. permissible leakage quantities. TA-LUFT According to “TA-Luft V 0,” leakage rates in Germany must be within the limits shown in → Tab. 55. The TA-Luft refers to the test according to ISO 15848-1. In other countries, the ISO standards and API standards mentioned are required and in- ternationally recognized. CLEAN AIR ACT The Clean Air Act defines maximum leak- age values for flanged joints, valves, pumps and agitators in the USA. The leakage tests are to be carried out according to EPA method 21 (sniffing method) with methane. API 622 API 622 is an international performance test for materials considering several fac- tors, such as temperature, pressure, and thermal and mechanical switching cycles. API 624 This is type testing of globe valves equipped with graphite packing against fugitive emissions. It requires that the tested valve packing has been previously tested according to API 622 and is suited for use at operating temperatures from –29 °C to +538 °C. CLASS TEST GAS HELIUM MEASURED LEAKAGE RATE [mg/(s x m)] NOTES A B C ≤ 10‒5 ≤ 10‒4 ≤ 10‒2 Typically with bellows seals or equivalent sealing systems for control valves reachable Typically with packings based on PTFE or made of elastomer materials reachable Typically with stem seals on the basis of expanded graphite reachable Tab. 54 ISO 15848-1: Graduation and the max. permissible leakage quantities 846

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T a b . 5 5 > 4 0 > 4 0 ≤ 4 0 ≤ 4 0 [ b a r ] P R E S S U R E L e a k a g e c l a s s e s i n T A - L u f t T E M P E R A T U R E R A N G E L E C K A G E C L A S S > 2 0 0 ≤ 2 0 0 > 2 0 0 ≤ 2 0 0 [ ° C ] C l a s s L C ≤ 1 0 ‒ 2 m g / ( s x m ) C l a s s L B ≤ 1 0 ‒ 4 m g / ( s x m ) 8 4 7 INDEX STUFFING BOX PACKINGS DIAPHRAGMS BOOTS & BELLOWS HYDRAULIC ACCUMULATORS SPECIAL SEALING PRODUCTS STATIC SEALS FLUID POWER APPLICATIONS – PNEUMATICS FLUID POWER APPLICATIONS – HYDRAULICS SEALS FOR ROTARY APPLICATIONS 8 . S t a n d a r d s f o r t h e R e d u c t i o n o f F u g i t i v e E m i s s i o n s INTRODUCTION & SERVICES MATERIALS AND PROCESS ENGINEERING

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Stuﬃng Box Packings 9. MEDIA TO BE SEALED 9.1 MEDIA TABLE MAIN MEDIA GROUP 1 ALKALIS 1.1 Diluted alkalis 6 8 5 4 n o l i m a R 4 0 2 6 t a t s o r A 5 1 2 6 I I n a l o r A 3 1 3 6 m e h c i n U 3 0 3 6 t a t s i n U 3 2 3 6 l a v i n U 5 7 3 6 m e h c l A 1 0 5 6 x e l f i f a r G 0 5 5 6 m a e t s o b r a C 5 6 5 6 S l a i z e p S - G 0 6 5 6 l a i z e p S - G 2 4 7 6 n o l i b m o K 0 0 0 7 t i d r e v i n U 8 8 5 6 x e l f i n U 0 5 3 6 c e t l a V 9 5 5 6 c e t l a V 0 0 2 7 c e t l a V 0 5 2 7 c e t l a V 0 9 2 7 c e t l a V 0 0 3 7 c e t l a V 6 1 2 6 S m e h c o r A C B B B B B B B B B B B B B B B B B B B B 1.2 Concentrated alkalis – B – – B B B B B B B B B B B B B – – B B 2 STEAM 2.1 ≤ 180 °C 2.2 ≤ 280 °C 2.3 ≤ 550 °C 3 VAPORS AND GASES 3.1 Inert gases, air 3.2 Volatile hydro-carbons; solvent vapors 3.3 Acidic gases 3.4 Oxygen 3.5 Hydrogen 4 SOLVENTS 4.1 Aliphatic and aromatic hydro-carbons, aldehyde, alcohols, esters, ketones, chlorinated hydro-carbons 5 OILS AND GREASES 5.1 Mineral oils and greases, plant and animal oils and greases 5.2 Synthetic oils, heat transfer oils 848 – C – B B – B B B B B B B B B B B – – B B – – – – – B B – – B B B B B B – – – – – – – B B B B – – – – – B – – B B – B – – B B C B B B B B B B B B B B B B B B B B B B B – B B B B B B B B B B B B B B B B B B B B – – – – – B – – – B – – B B B B – B B B – – B – B C B B B – B B B B B B B B B – – – – B – – – B – – – – B B B B B B B – – – – B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B B – B B B B – B B B – B B – B – B B B – B –

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9. Media to be Sealed 3 1 3 6 m e h c i n U 3 0 3 6 t a t s i n U 3 2 3 6 l a v i n U 5 7 3 6 m e h c l A 1 0 5 6 x e l f i f a r G 0 5 5 6 m a e t s o b r a C 5 6 5 6 S l a i z e p S - G 0 6 5 6 l a i z e p S - G 2 4 7 6 n o l i b m o K 0 0 0 7 t i d r e v i n U 8 8 5 6 x e l f i n U 0 5 3 6 c e t l a V 9 5 5 6 c e t l a V 0 0 2 7 c e t l a V 0 5 2 7 c e t l a V 0 9 2 7 c e t l a V 0 0 3 7 c e t l a V 6 8 5 4 n o l i m a R 4 0 2 6 t a t s o r A 5 1 2 6 I I n a l o r A 6 1 2 6 S m e h c o r A I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P – B B B B B B B B B B B B B B B B B B B B – C C C B B B B B B B B C B B B B C C B B – – – – B B B B C C C C – B – C C – – C C S L A E S C I T A T S MAIN MEDIA GROUP 6 ACIDS 6.1 Strongly diluted organic and inorganic acids 6.2 Concentrated acids, inorganic acids of medium concentration 6.3 Concentrated inorganic acids 7 NEUTRAL AQUEOUS SOLUTIONS 7.1 Salt solutions 8 OTHER ORGANIC BONDS B B B B B B B B B B B B B B B B B B B B B 8.1 Nitrile, amine, lactam – – B B B B B B B – B B B B – B B B B – – 9 WATER 9.1 Drinking water, sea water, waste water, hot water up to +100 °C 9.2 Hot water over +100 °C, boiler feed water B B B B B B B B B B B B B B B B B B B B B C C B B B B B B B B B B B B B B B B B B B B suited C conditionally suited – not suited G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 849 X E D N I

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Stuﬃng Box Packings 9.2 MEDIA REGISTER OF STUFFING BOX PACKINGS For explanations of the ordinal numbers, see → “9.1 Media Table” on page 848. A Accumulator acid Acetic acid Acetic acid, glacial Acetic anhydride Acetone Acetylene Acrylnitrile Adipic acid Alum, aqueous Aluminum acetate Aluminum chloride Aluminum sulphate Ammonia, aqueous Ammonia, gaseous Ammonia, liquid Ammonium chloride Aniline Asphalt ASTM oils 1, 2, 3 B Barium salts, aqueous Benzaldehyde Benzene Benzine Benzoic acid, aqueous Benzyl alcohol Benzyl chloride Bitumen Blast furnace gas Boiler feed water Bonderite®/P3® alkali Borax, aqueous Brake fluid (ATE blue) Bromine Butadiene Butane Butanediol Butyl acetate Butyl alcohol Butylene glycol Butyraldehyde Butyric acid 3.3 3.2; 4 3.2; 4 4 4 4 4 4 6.1; 6.2 7 7; 6.1 7 6.1; 6.2 8 8 3.1 4 3.1 4 C Calcium acetate Calcium bisulfites Calcium chloride, aqueous Calcium hypochloride Camphor Caprolactam Carbon dioxide, gaseous Carbon disulfide Carbon monoxide Carbon tetrachloride Caustic potash (= potassium hydroxide) 1.1; 1.2 Caustic soda/sodium hydroxide 1.1; 1.2 4 Chlorbenzene 4 Chlorinated paraffin Chlorine water RT 6.2; 6.3 3.3 Chlorine, wet 6.2; 6.3 Chloroacetic acid 4 Chloroform 6.1; 6.2 Chlorosulfonic acid Chromic acid 6.2; 6.3 6.1; 6.2 Citric acid 5.1 Coconut oil 5.1 Cod liver oil Coking-oven gas 3.1 6.2 6.1; 6.2 6.2 6.2 4 3.2 8 6.1; 6.2 6.1 7 6.3 6.1 1.1; 1.2 1.2 1.2 7 8 4; 5.1 5.1 7 4 4 4 6.1; 6.2 4 4 4; 5.1 3.2 9.1; 9.2 1.1; 1.2 7 5.2 850

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9. Media to be Sealed Copper acetate, aqueous Copper chloride, aqueous Copper sulfite, aqueous Cresylic acid Cyclohexane Cyclohexanol Cyclohexanone D Dibenzyl ether Dibutyl ether Dibutyl phthalate Diesel oil Diethanolamine Diethyl ether Diethyl sebacate Diethylene glycol Dimethylformamide Dioctyl phthalate Diphenyl oxide Diphyl Dowtherm A E Ethane Ethanolamine Ethyl acetate Ethyl alcohol Ethyl benzol Ethyl chloride Ethylenchloride Ethylene Ethylene dichloride Ethylene glycol Ethylene oxide 7 7 7 4 4 4 4 4 4 4 5.1 8 4 4 4 4 4 4 5.2 5.2 3.2 8 4 4 4 4 4 3.2 4 4 3.2 F Fat Fatty acids Fatty alcohol Fecal matter Fixing bath Fluorescent gas Fluorine, dry Fluorobenzene Formaldehyde Formic acid Freon types Frigen types G Gas oil Gelatine Glauber’s salt, aqueous Glue, aqueous Glycerine Glycol H Heat transfer oil Heating oil Heptane Hexane Hydraulic fluids/ Mineral oil based Hydraulic fluids/ Phosphate ester based Hydrazine Hydrobromic acid Hydrochloric acid 5.1 6.1; 6.2 4 9.1 1.1 3.2 3.3 4 4; 1.1 6.1; 6.2 4 4 5.1 7 7 7 4 4 5.2 5.1 4 4 5.1 5.2 1.1; 1.2 6.1; 6.2 6.2; 6.3 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 851 X E D N I

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Stuﬃng Box Packings For explanations of the ordinal numbers, see → “9.1 Media Table” on page 848. Maleic acid anhydride Methacrylic acid methyl ester Methane Methanol Methyl ethyl ketone (MEK) Methyl glycol acetate Methyl isobutyl ketone Methylen chloride Milk of lime Mineral oil Mineral oil Monochloroacetic acid Monochlorobenzene 6.2 4 3.2 4 4 4 4 4 1.1; 1.2 5.1; 4 5.1 6.2; 6.3 4 Hydrocyanic acid Hydrofluoric acid, concentrated Hydrogen chloride gas Hydrogen peroxide 6.1; 6.2 6.2 3.3 7 I Iodine tincture Iodine-potassium iodide, aqueous Iron III Chloride, aqueous Iron nitrate Iron sulfate, aqueous Isobutyl alcohol Isobutyl ketone Isooctane Isopropanol Isopropyl acetate Isopropyl ether J Jet fuel (carburator) L Lactic acid Lauryl alcohol Lead acetate, aqueous Lead salts, aqueous Lithium chloride M Magnesium chloride Magnesium hydroxide Magnesium sulphate Maleic acid 852 4 7 7 6.1 7 4 4 4 4 4 4 4 6.1 4 7 7 7 N Naphta Naphtalen Natural gas Nickel sulfate Nitric acid Nitrobenzene O Oleum Oxalic acid Oxygen, gaseous P Palmitic acid Paper pulp Paraffin Paraffin oil Peanut oil 7 1.1; 1.2 7 6.1; 6.2 4 4 3.2 7 6.2; 6.3 4 6.3 6.1; 6.2 3.4 6.1 7 5.1 5.1 5.1

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9. Media to be Sealed Pentane Perchloric acid Perchloroethylene Petroleum Petroleum ether Phenol, aqueous Phosphoric acid Phthalic acid Phthalic anhydride Pine needle oil Potassium acetate, aqueous Potassium bromide, aqueous Potassium carbonate, aqueous Potassium chlorate, aqueous Potassium chloride, aqueous Potassium cyanide, aqueous Potassium hydroxide Potassium nitrate, aqueous Potassium silicate, aqueous Pressure fluids according to DIN 51524 Group H, HL, H-LP Propane Propanol Propyl acetate Propylene glycol 4 6.2; 6.3 4 5:1, 4 4 6.1; 6.2 6.1; 6.2 6.1; 6.2 6.1; 6.2 5.1 7 7 7; 1.1 7 7 7 1.1; 1.2 7 7 5.1; 5.2 3.2; 4 4 4 4 R Roasted gases, dry 3.2; 3.3 S Salicylic acid Sea water Seawater Silicofluoric acid Silicone oil Silver nitrate, aqueous Soap solution Socium cyanide Sodium carbonate Sodium chloride 6.1; 6.2 9.1 9.1 6.2; 6.3 5.2 7 7 7 1.1 7 Sodium hypochlorite Sodium nitrite Sodium phosphate Sodium silicate Sodium sulfide Sodium sulfite Sodium sulphate Sodium thiosulfate Steam up to 180 °C Steam up to 280 °C Steam up to 550 °C Stearic acid Sulphite alkali Sulphur dioxide Sulphuric acid Sulphurous acid T Tallow Tannic acid Tannin Tar Tartaric acid Tetrahydrofuran Toluene Tributyl phosphate Trichloroacetic acid Trichloroethylene Triethanolamine Turpentine U Urea, aqueous V Vinyl acetate Vinyl chloride, aqueous 6.1; 6.2 7 7 7 7 7; 6.1 7 7 2.1 2.2 2.3 6.1 6.1; 6.2 3.3 6.2; 6.3 6.2; 6.3 5.1 6.1; 6.2 6.1 5.1 6.1; 6.2 4 4 4 6.2; 6.3 4 8 4 7 4 8 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 853 X E D N I

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Stuﬃng Box Packings For explanations of the ordinal numbers, see → “9.1 Media Table” on page 848. W Waste water Water glass Water steam Water, boiler feed water Water, cold Water, over +100 °C Water, sea water Water, up to +100 °C Wood pulp X Xylene Z Zinc chloride Zinc sulphate 9.1 7 2.1–2.3 9.1; 9.2 9.1 9.2 9.1 9.1 7; 6.1 4 6.1; 6.2 6.1 854

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10. Handling and Installation of Stuffing Box Packings 10. HANDLING AND INSTALLATION OF STUFFING BOX PACKINGS I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I 10.1 GENERAL Pre-pressed packing rings are used for packing stuffing box packs. Rings are best cut from the length as de- livered with the aid of a Merkel® packing cutter, cut to exactly the correct length and shaped into a ring around the shaft or spindle during installation. The stuffing box can also be wound around a shaft or tube with the same diameter and be cut to size. A bevel cut is essential for good sealing properties. Adhesive tape, with- out bonding agent can be applied to both sides of the cut ends prior to cutting to prevent fraying. The finished rings are then inserted one after the other in the stuffing box with the cuts offset to one another and tight- ened using the gland nuts. The stuffing box should be tightened firmly initially so that it can mold to the interior of the gland. The gland nuts are then loosened again and re-tightened with moderate force. 10.2 PRE-COMPRESSION OF PACKING The correct pre-compression and operat- ing compression is dependent on the type of packing and its application. The appropriate nut forces can only be meas- ured with a torque wrench or similar in- strument. Operating compression of 1.05 – 2x times the pressure of the medium is used for pump packings. A minimum stress of 0.5 to 1.5 N/mm2 is required here. R O F S L A E S Y R A T O R S N O T A C I I L P P A 45° Cut packing at 45° First open axially - then slightly radially Insert cuts first Fig. 377 Cutting packing rings VALVE PACKINGS Valve packings are used with an operating compression of 2 to 5 x medium pressure and a minimum stress of 5 N/mm2. In addition to these general instructions, separate instructions are available for certain packings and special applications. RUNNING-IN THE NEW PACKING Packings are particularly susceptible to high temperature damage during the running-in phase. It is therefore very im- portant to take special notice of the shaft temperature during the initial startup. If the packing runs too hot, the pump must be stopped. After a short cooling down period a regular drip should appear and the pump can be started up again. It may be necessary to repeat this proce- dure several times until a regular leakage rate appears from the shaft. Map-Marker-Exclamation Minimum clamping force for pump packings R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 855 X E D N I

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10.5 GAP WIDTHS The permissible gap widths between the shaft (plunger) and the gland bore must be 2/100 of the packing width. If the gap widths are larger or the packing has a ten- dency to extrude, suitable anti-extrusion end rings must be provided. A copy of our current installation instruc- tions is included with each delivery. 10.6 STORAGE Stuffing box packings should be stored in cartons, flat on shelves, in dry rooms with normal temperature and humidity, pro- tected from dirt, mechanical damage, extreme temperatures, sunlight or other radiation. Shelf life depends not only on the above storage conditions, but also on the material itself. A unique batch number is placed on each carton of a stuffing box in addition for traceability. Stuﬃng Box Packings 10.3 INSTALLATION OF MOLDED RINGS Molded packing rings must be handled carefully during installation so that the sealing properties of these rings are not lost through unnecessary deformation of the cross-section. If the rings have to be opened to fit onto the shaft, the ring ends should first of all be slightly pulled apart, but in an axial direction so that a small gap appears which will fit over the shaft. The opening in a radial direction should be avoided as this deforms the section. Install with the cut sections forward. 10.4 TOLERANCES AND SURFACES The following surface finishes are re- commended to keep friction and wear of the shaft and piston as low as possible. The finer or smoother the surface finish, the lower the friction and the longer the packing life. y Rotary pump shafts, Plungers and spindles Ra ≤ 0.25 µm Ra ≤ 2.50 µm y Housing bores These values are only valid for general applications. For high demands on tight- ness and service life, the Ra value for shafts or plungers and spindles must be reduced to Ra values ≤ 0.1 µm. On rotary pumps, the shaft runout must be less than 1/1000 of the shaft diameter. To achieve lower leakage in valves, the shaft runout must not be more than 1/100 of the packing width. Map-Marker-Exclamation Permissible gap widths between the shaft and gland bore 856

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11. Equipment for Disassembly and Cutting of Packings 11. EQUIPMENT FOR DISASSEMBLY AND CUTTING OF PACKINGS 11.2 MERKEL® RING SEGMENTS 7511 Screw-on metal ring segments are avail- able for the packing extractors to install the packings. This allows the packing rings to be inserted easily, evenly and gently, simplifying installation. Thrust piece ring segment with tubular extension and internal thread, for pack- ing extractors sizes 0 to 3. 11.1 MERKEL® PACKING EXTRACTOR 7500 Packing extractors have been specially developed for fast and gentle removal of old packings. The forged, helical tip is fric- tion-locked to the extractor shaft. With its high pitch, it easily bores firmly into all types of braided and woven packings. The flexible and strong shaft makes it easy to reach even hard-to-reach packing spaces (→ chapter “Services – Installation and Deinstallation aids”, page 14). Packing extractors are supplied in sets in a practical container. Each set consists of one pair of steel extractors, in the follow- ing dimensions: y Size 3: 22 cm for stuffing box packings from 6 mm Fig. 379 Pressure piece ring segment y Size 2: 33 cm for stuffing box packings from 10 mm y Size 1: 44 cm for stuffing box packings from 13 mm BENEFITS FOR THE CUSTOMER y the flexible extractor shaft also adapts to hard-to-reach stuffing boxes y Size 0: 50 cm for stuffing box packings y the helical tips are interchangeable from 16 mm y as packing extractor set with sizes 1, 2 and 3 11.3 MERKEL® PACKING CUTTING GAUGE 7505 The universal packing cutting gauge was developed for practical cutting of packings from the roll. This packing cutter enables to cut precise lengths with correctly scarved ends to produce rings with exact dimensions. Fig. 378 Packing extractor Fig. 380 Packing cutting gauge 7505 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 857 X E D N I

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Stuﬃng Box Packings BENEFITS FOR THE CUSTOMER y made of rigid plastic with lateral fas- tening means y dimension scale in mm and inches y for radial diagonal cut 45° in shaft/ spindle area y maximum cutting length 470 mm y clamping fixture for holding the pack- ing at the slot which guides the knife y graduations indicating cross section of the packing on the securable aluminium slide, and graduations indicating shaft diameters on the body. y finger protection y practical quality cutter as an accessory (can be supplied as the spare cutter 7513) 858

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12. TROUBLESHOOTING 12. Troubleshooting 12.1 GENERAL It is not always clear why a stuffing box packing is not working properly. However, by carefully checking the rings used, the causes can often be found. 12.2 INSTALLATION One of the most common reasons for stuffing box packing failure is that packing rings are too short. When rings are cut too short, compression of the packing set causes subsequent rings to move into the clearances. The rings will then have axial “bumps,” which can be clearly seen in the following illustrations. When calculating the correct length of a packing ring, the shrinkage behavior of different yarn materials must be taken into account. The use of a packing cutter and technical support from FST’s engi- neering department helps to avoid this problem. 12.3 EXTRUSION 1 If the gap between the shaft and the housing is too large, extrusion of the packing rings towards the medium may occur. A gap between the shaft and the stuffing box gland can lead to a similar effect. Excessive pressure of the gland on the stuffing box packing or misalignment of the shaft can also cause extrusion of the packing. There are several solutions to this prob- lem: Braided anti-extrusion packing rings protect soft packings from extrusion. Alternatively, a metallic washer can be used at the stuffing box bottom to reduce the gap size. Alternatively, the stuffing box design can be modified to minimize gaps. In the case of shaft misalignment, replacing the bearings by new ones will improve performance. Map-marker-edit Metal washer at the bottom of the stuffing box to reduce the size of the gap Fig. 381 Rings cut too short If a disassembled packing set exhibits these typical characteristics, care should be taken to cut each ring long enough to avoid gaps between packing ends. I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 859 X E D N I

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Stuﬃng Box Packings Fig. 382 Extrusion 1 Fig. 383 Extrusion 2 12.4 EXTRUSION 2 The packing shows extrusion between the shaft and the stuffing box gland. Ex- cessive gland pressure or too large a seal- ing gap between the shaft and the stuff- ing box gland are the cause. Installation of the correct end rings should solve the problem. 860

861

12. Troubleshooting 12.5 SHAFT BALANCING If all packing rings of a set have unequal radial thickness on one side of their cross-section, the shaft is concentrically misaligned in one direction. An indication of the misalignment could be a more dif- ficult installation of the packing rings due to unequal spacing in the stuffing box. The asymmetrical load causes additional wear of the packing rings, which leads to a burnt inner ring surface as well as leakage. In extreme cases, the shaft can be dam- aged by friction between the stuffing box or housing. This leads to a shorter service life of the packing set and significantly higher maintenance costs. To avoid this, the shaft bearing should be improved or replaced. parts of the ring, leakage will be difficult to control. This installation error can be seen from the uneven surface of the packing ring. In addition, the stuffing box cannot be in- stalled upright. To avoid this error, ring installation pro- cedures should be performed carefully. To do so, bring the two cut ends togeth- er and then insert them into the stuffing box. Then press the remaining part of the ring down to the end with the same force. Install other rings in the same manner. Fig. 384 Shaft balancing 12.6 AXIAL DEFORMATION OF THE PACKING If the cut ends of a packing ring overlap during installation, material can overflow at the cutting joint. This can result in compression not being evenly distributed across the rings. Overlapping areas create high friction, which leads to overheating and wear be- tween the packing and the shaft surface. Due to insufficient load on the other Fig. 385 Axial deformation of the packing 12.7 SHAFT RUNOUT Shaft deflection in rotary pumps or agi- tators can have various causes, such as imbalance, vibration, pipe stress or cavi- tation. For the packing seal, this means higher leakage that cannot be reduced by tightening the stuffing box. After removal of the packing, the rings typically have a smaller radial thickness in one area than before installation. PTFE- based packings in particular suffer here, as they quickly undergo plastic deformation. Packings made of aramid or carbon yarn I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 861 X E D N I

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Stuﬃng Box Packings are more flexible and can tolerate shaft deflection to a certain extent. However, to improve sealing performance, it is im- portant to improve the underlying condi- tion by replacing the shaft bearing. Fig. 386 Shaft runout 862

863

INDEX Index A Abrasion Abrasive particles Accelerators Acrylic fibers Acrylonitrile Activators Additives Adhesive part Advantages Agglomerates Aggregate state Amorphous Analysis Anti-ageing agents Approval Aramid fabric Aramid fibers Aromatics Assembly injection molding ATEX Axial deformation 49, 165, 171, 301, 387, 624 384 104, 111 842–843 180, 182, 412, 777, 802 104, 112 296 331, 567 842–844 216 216 37, 216 16, 381, 389, 401, 524–525, 623, 797 104 143 805 842–843 216 702, 706 313, 664, 666, 669–670 861 B Binding seam Block copolymers Blow-by effect Bore Brownian molecular motion Bubble formation 167–168 42, 47 531 384, 636 216 168, 387 C Calculation Carbon Yarns Carrier Carrier parts Chamfer characterization Circular blanks Circumferential elongation Circumferential speed Clamping Classification Clean Air Act Cleanliness Coagencia Coating Coaxiality Cold runner technology Components 152, 309, 470–471, 716 843 123, 259, 643, 663, 675, 701 123, 259, 663 331, 399, 838 401, 403, 409, 499, 501 679 789, 809 347, 349, 351, 353, 355–356, 562, 564 753, 787 36–37, 42, 178, 214–215, 302, 384, 458, 557 846 171 112 11, 590, 620, 631–632, 793 325, 328 135 20, 22, 134, 178, 360, 367, 554, 654, 683 Component stress Composite parts Composition Compounds Compressed air Compression Compression Molding Compression rate Compression set Construction Contact zone Contaminants Corrective factors Corrosion Corrosion protection Counterbore Counter surface Cracking Cross-linking Cross-linking agents Cross-linking characteristics Cross-linking density Cross-linking kinetics Cross-linking system Cycle test rigs 787–788 662 103 20 574 49, 133, 151, 487, 612, 855 133 612 49, 151, 487 384, 808, 837–838 286 298 718 337, 384, 398, 400 384, 400 633 460, 493 175, 386, 529 111, 114–120, 132, 144–145 111, 117 115 114 144–145 111 408 D Damage Damage description Damage hypothesis Damage pattern Damage report Deformation Deinstallation Deinstallation aids Delamination Density Dependencies Design examples Design information Development Diaphragm fabrics Diesel effect Dimensional tolerances Dimensioning Dimensions Dirt 16, 159–160, 163, 172, 174, 328, 381, 385, 389, 391, 394–397, 399–401, 524–526, 622–623, 753, 755, 797 163, 524 163, 524–525 172, 174 163, 524–525 287, 363, 365, 395, 464, 492, 567, 861 14, 379, 522–523, 622, 753, 857 379, 522, 622, 753, 857 165, 169–170 144, 302 460 789 413 17, 143, 297, 588 782, 805 527 795 470–472, 786, 796 130, 151, 286, 325, 534, 602, 637 338, 347, 349, 351, 353, 355–356, 384, 391–394, 400, 552, 562, 564, 731 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 863 X E D N I

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Index 864 Dispersing Dust lip E Eccentricity Effective area Effective diameter Effects Elasticity Elasticity modulus Elastomer 217 259, 272, 338 171, 384 772, 810 783, 809 157 58, 217, 784 784 42–43, 72, 104, 130, 157, 178 Material Static Seals 624, 636, 643, 648 Special Sealing Products 650, 660, 663, 673, 675, 699 42–43, 72 663, 699 787–789 6, 846 358 622, 661 133, 136, 467, 484, 859–860 467 136 Elastomer alloys Elastomer composite parts Elongation stress Emissions Error handling Expansion Extrusion Extrusion gap Extrusion process F Fabric Failure diagnosis Fatigue Fillers Flexible of service Flow behavior Flow erosion Fluid Connect Fluid connections Food & Beverage Foreign bodies Form Frequency behavior Friction Friction behavior Functionality Functional tests Function estimation 480, 488, 796, 798 736 144 104–105, 107 273 144, 146 527 654, 703, 705–706 733 21 529 590 144 490, 492, 509–510, 513, 516, 567, 572, 661, 793 492, 509–510, 513, 516 666, 668, 670, 698, 723–724, 727 407 696 G Gap extrusion Gap widths Gas connections Gas filling pressure 170–171, 477, 528, 610, 624 856 733 715 Gas losses Gearboxes Gear oils Geometry Glass fibers Glass transition temperature Gluing in Graphite yarns Greases Greasing Groove filling rate Grooving Guideline values 729 230 302, 304, 306 165, 469 843–844 217 367 843 297–298, 302, 304, 306, 347, 349, 351, 353, 355–356, 845 359, 392–394, 834 609 387 608, 613–615 H Hammer installation Hardness Hard turning Heat resistance Heavy industry High-speed test rigs Hooke‘s law Hot cracks Housing Housing bore Housing diameter Hydraulic power units Hydrolysis 366 103, 144, 147–148, 302, 326, 411, 749, 790 324 156, 173 250, 252, 254, 299 408 218 165, 168 338, 390, 399, 463, 783, 789, 809, 856 399 783, 809 299 174, 484, 530 845 228, 236 325, 467, 567 309, 479 785 134 578 806 177, 736 I Impregnations Industrial gearboxes Influences Influencing factors Inherent resistance Injection Molding Insertion chamfers Insert parts Inspection Installation Service Rotary Seals Fluid Power – Hydraulics Fluid Power – Pneumatics Static Seals 14 316, 328, 344, 361–363, 365, 368–377, 379–380, 391–392, 395–396, 413 460, 514, 517–522, 534 571, 578, 580–582 604, 622, 633–634, 642

865

Index Mixing process Mixture production Mobile hydraulics Modeling Mode of operation Modification Molded rings Molding sand Mounting Mounting strap 143 105–106, 126 422, 424, 426, 432, 446 407 779 13, 333, 337, 793 856 384 521, 562, 564, 715, 728 521 N Naphthenes Natural frequency Non-polar substances 218 720 38 O Offset Operating data Operating pressure Overpressure Ozone 165, 170, 603, 663 786, 790 633 383–384 49, 144, 158, 175, 204, 384 P Packaging Packing Cutting Gauge Packing Extractor Paraffins Particle Class Particles Permanent deformation Permeability Permeation Peroxides Physical effects Piston 178, 359 857 857 110 575 127, 388 171, 179, 624 218 160, 174, 601, 661 120 526 430, 452, 456, Fluid Power – Hydraulics 459, 462–463, 466, 485 Fluid Power – Pneumatics 542, 546, 548, 556, 558–559, 562, 564 Diaphragms 775, 789 430, 542, 558 104, 107, 219 219 520 324 538, 542, 544, 546, 548, 550 805 42 42 Piston seals Plasticizers Plasticizing Pliers installation Plunge grinding Pneumatic cylinders Polyester fabric Polyetheramides Polyether esters I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 865 X E D N I 661 Special Sealing Products 753, 757 Bellows Diaphragms 774–776, 795 Stuffing Box Packings 855–857, 859–860 328 775–776 715, 728, 731 460, 571, 661, 726 362, 519, 522, 581 293, 397 463, 465 716 717–718 218 Installation chamfer Installation dimensions Installation position Installation space Installation tool Interactions Interspace Isothermal changes Isothermal charging Isotropy L Laboratory Tests Laminated fabrics Lead Leakage Load Long-term failure Lube & Seal Lubricant 18, 626 488 20, 200, 384, 404, 406, 608, 614–619, 808, 852 144, 381, 385, 828, 847 180, 460, 516, 534, 788 384 12, 297, 359 327, 382, 384 M Macro-lead Manual installation Manufacturing errors Material abbreviations Material models Material selection Material testing Mating rings Mechanical engineering Mechanical stress Media 405–406 520 167 180 159 48, 637, 639–640, 664, 666, 668, 670, 747 18, 143 685 742 170, 755 Fluid Power – Hydraulics Fluid Power – Pneumatics Static Seals Stuffing Box Packings 485 574 636, 661 848 698-699 384 477 405–406 404 295, 347, 349, 351, 353, 355–356, 632, 675, 848 490 Metal Metal abrasion Metallic contact Micro-lead Microscopy Mineral oils Mixed friction

866

Index 866 Polymer classes Polymer materials Polyolefins Polytropic change Preselection 39 36, 39 42, 78 717 Rotary Seals Fluid Power – Hydraulics Fluid Power – Pneumatics Stuffing Box Packings 338 501 562 831 261, 313, 316, 338, 347, Pressure 349, 351, 353, 355–356, 383, 408 464 Pressure buildup 463 Pressure deformation 789, 809 Pressure differential Pressure relief 448, 464–465, 509–510, 514 509–510, 514 Pressure relief function 720 Pressure surge damping 408 Pressure test rigs 734 Pressure vessels Pretreatment 124 456, 459, 463 Primary seal 15, 620 Printing 126, 797 Procedure Processes 109 246, 248, 250, 299 Process industry Processing aids 104, 109 Processing process 143 15, 620 Product Marking 465, 481, 485–486 Product overview Profile thickness 469 110, 338, 359 Protection 10–20, 24, 694, 699 Purchasing R Radial force Recipe development Retaining claw Reusability RGT rule Rod seals Rolling gap Roughness Roughness parameters Rubber Running-in Runout deviation 219, 287 143 332 413, 633, 635 157, 219 418, 466, 538, 663 783 331, 384, 398, 411, 413, 497 497 20, 22, 34, 36, 42, 50, 103–105, 107–110, 127, 129, 163, 213–215, 218, 220–221, 405, 791 855 328 S 404 Seal counter surface 259, 272, 386, 388, 529 Sealing edge 482 Sealing effect 287 Sealing function 287 Sealing lip geometry 285, 318 Sealing mechanism 384 Sealing medium 460, 555 Sealing solutions 648, 664, 669–670 Seat valves 456, 459, 463 Secondary seal 158 Service life 7–26 Services 861 Shaft balancing 324, 385 Shaft machining 861–862 Shaft runout 109, 130 Shaping 384 Short-term failure 381 Short term leakage 844 Silicate Yarns 409 Simulation 359–360 Single packaging 420, 460 Single seal 139 Sintering 391–392, 394, 396, Sources of error 398, 400 228, 263, 319 Special design 606 Special grooves 54, 105 Speciality Rubbers 304, 306, 340 Special materials Special profiles 650, 683 Speed 144, 180, 310, 325, 327, 338, 384, 408, 461–462 Spring Standardization Proposals Standard material Standards 755, 846 Standard sealing systems Static seals Stem seals Stick-slip effect Stiffness Storage Storage tests Storage time Stress relaxation Stretch Suggestions for the assessment 460 36–37, 454, 456, 466, 656, 658 648, 670 220 115, 332 294, 358, 360, 367, 369, 391–392, 394, 396–397, 635, 714, 722, 729–730, 732, 756, 856 154, 293 360 159 611 179 259, 400, 840 833 299, 773 22, 148, 151, 308, 638, 641, 661,

867

Index W Water Wear resistance Wetting Y Yarns 212, 254, 274, 303, 305, 307, 384, 482, 487, 575, 762, 803, 833–836, 854 159 367 842–844 Sulfur Surface Surface assessment Surface finish Surface finishing Surface hardness Surface quality Surface recommendations Surface structure Surface treatment Sustainability Swelling Symmetrical seals 118–119 36, 110, 144, 175, 323, 363, 384, 406, 493, 496, 499, 534, 572, 590, 620, 622, 632, 661, 753, 793 496 572, 661 493 323 534, 753 572 384 590, 620, 622 5 165, 624, 798 440 T Tempering Tensile tests Tension Test Benches Testing of the finished part Test rig Test specimen production Thermal expansion Thread method Tightening torque Tightness Tolerance Tool competence Tools Training Transfer Molding Trapezoidal groove Triangular groove Twisting Types of styrenes 121 150 259, 810 17, 382, 623, 626, 755 143 407 143 144, 331, 625 382, 405 633, 636 313, 347, 349, 351, 353, 355–356 323, 331, 411, 612, 679–681 132 14, 20, 23–24, 524, 800 19, 385, 394–396 133 605 605 171, 529, 625 42 V Valves Variety of materials VDI Vibrations Viscoelasticity Vulcanizates Vulcanization Vulcanization retarders 566, 592, 652, 656, 663, 814, 818, 824, 826, 831–832, 846 103 170, 174, 797 337, 384 221 61 104, 112, 119 112 I & N O T C U D O R T N S E C I V R E S I D N A S L A I R E T A M S S E C O R P I G N R E E N G N E I R O F S L A E S Y R A T O R S N O T A C I I L P P A R E W O P D U L F I – S N O T A C I I L P P A S C I L U A R D Y H R E W O P D U L F I – S N O T A C I I L P P A S C I T A M U E N P S L A E S C I T A T S G N I L A E S L A I C E P S S T C U D O R P C I L U A R D Y H S R O T A L U M U C C A S W O L L E B & S T O O B S M G A R H P A D I X O B G N I F F U T S I S G N K C A P 867 X E D N I

868

Editorial Information Freudenberg FST GmbH Höhnerweg 2–4 69469 Weinheim, Germany Telephone: +49(0)6201 960-66 66 E-Mail: info@fst.com www.fst.com

Technical Manual 2025

Table of Contents

Services

Table of Contents

Materials and Process Engineering

Table of Contents

Seals for Rotary Applications

Table of Contents

Seals for Fluid Power Applications – Hydraulics

Table of Contents

Seals for Fluid Power Applications – Pneumatics

Table of Contents

Static Seals

Table of Contents

Special Sealing Products

Table of Contents

Hydraulic Accumulators

Table of Contents

Boots & Bellows

Table of Contents

Diaphragms

Table of Contents

Stuffing Box Packings

Table of Contents

Index