Sealing technology manual for the process industry - Low pressure profiles

LOW PRESSURE PROFILES Large areas are difficult to seal with commonly made products because tools are too expensive or unfeasible to realize. With the help of low pressure profiles, it is possible to seal these difficult points. Profiles and cords Typical examples are oven door seals. For the standard pro- gram, there is a variety of different tools for different ma- terials available. By switching from mold-based to low pres- sure parts, tool costs can be saved when developing cus- tomized individual applications. Freudenberg has developed a special vulcanization process in which the cord and the joint are made of the same mate- rial. Thus, a uniform quality of the seal is achieved. In conventional low pressure gaskets of other manufacturers, the joint is often connected by means of an adhesive, result- ing in a significant difference in quality. In contrast to the seals made by Freudenberg, the joint here is not reliably re- sistant to thermal influences and process media or to clean- ing agents and steam sterilization. Freudenberg offers low pressure profiles and rings in the following elastomers: • 70 EPDM 391: resistant to water, steam, acid and alkali solution • 70 EPDM 471: resistant to disinfectants and CIP/SIP media • 75 Fluoroprene® XP 41: resistant to steam, fat and CIP/SIP media • 80 NBR 217383: good low temperature flexibility and abrasion resistance Inflatable seals Wherever the containers and doors of systems must be pro- tected against germs and dirt, the gap bridgings are sealed with inflatable profiles. In laboratories and research insti- tutes, the standard silicone material often creates problems due to insufficient stability. Also, the profiles of conven- tional inflatable seals often stick to the door frame and make it difficult to open the door, which in turn damages the seal. To produce a seal that is fully closed around the entire door frame, the two ends of the profile are butt joint-vulcanized. The molecules cross-link at the joint to the same material as the profile. Consequently, the profile at the joint seals as re- liably as at all other points. The FDA-compliant material 70 EPDM 471 is ideal for use under aggressive sterilization and cleaning conditions. Thanks to its high abrasion resistance, long service lives can be achieved. During the cleaning pro- cess, the gasket is inflated, resulting in high contact stress preventing leakage. After cleaning, the seal is relaxed again and the door opens without damaging the seal. Freuden- berg offers inflatable seals on request even with a specific valve matched to the seal that controls the supply of com- pressed air. Instead of a threaded coupling, this valve works by means of a click mechanism, making it easier to install. THE ADVANTAGES AT A GLANCE • Seals reliably against external influences • Easy opening and closing of doors, for example • Long service life • Very good chemical and thermal resistance • Seal and valve are perfectly matched • Individual dimensions by means of butt joint-vulcanization Seal under pressure Evacuated state Product portfolio 86

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