Sealing technology manual for the process industry - Hygienic Usit rings

HYGIENIC USIT RINGS Freudenberg‘s Hygienic Usit® is a product developed specifi- cally for the requirements of the process industry which sets standards in purity. Since it was in the past not possible to implement hygienic screw fittings, machine manufacturers and operators re- sorted to welding solutions. However, welded connections cannot be separated again easily. Still other system manu- facturers often employ conventional, non EHEDG-compliant fittings in or on the product space. This carries the risk that product residues accumulate under the screw head and be- come a source of contamination. The tightening of the screw already holds numerous sources of error, e.g. damage to the surface of conventional screws by the mounting tool. Freudenberg‘s Hygienic Usit® offers the possibility to realize hygienic screw connections. Thanks to the cooperation with the company NovoNox, the washers can be purchased with hygienic screws and cap nuts. The connection is available in the dimensions M4, M5, M6, M8, M10, M12 and M16. Addi- tionally we offer bolts and cap nuts in M3 designed for the M4 washer. Also in combination with a standard hexagon screw with flange according to DIN EN 1665, the Hygienic Usit® prevents the formation of bacteria. In open processes, where corrosion is an issue due to the wet environment, the Hygienic Usit® minimizes the risk of corrosion because of the prevention of bacteria. But the surface properties of the standard screws are not compliant to Hygienic Design standards. For this reason they are not recommended for applications with direct product contact. The screws and cap nuts with collar from NovoNox conform to 3-A® Sanitary Standards, are polished to a high shine and achieve a roughness depth of up to max. Ra = 0.04 µm, thanks to special manufacturing processes. The unique sur- face finish is free of flash and dimples which would preclude a hygienic design. Furthermore, NovoNox has patented spe- cial sockets with protective plastic inserts that do not dam- age the screws when tightening. Applications • In closed process steps for areas in contact with the product • In open processes, to ensure the complete exterior cleaning and steam sterilization of the plant Compounds The elastomer bead of the standard Hygienic Usit® is made from three EPDM variants. They are all suited for direct con- tact with food and pharmaceuticals and are resistant against CIP/SIP media. The black EPDM 291 ist the standard compound for the process industry. The white EPDM 253815 is especially interesting for the pharmaceutical in- dustry, while the blue EPDM 217676 is used as a variant in color. For applications with aggressive media or high tem- peratures, we offer the Hygienic Usit® made from our fluor- inated Fluoroprene® XP 41 material (on request). This blue universal material also minimizes flavor transfer. THE ADVANTAGES AT A GLANCE • EHEDG- and 3-A® Sanitary Standards-certified • Optimally matched screw-cap nut-Usit composite • Prevention of contamination due to dead space-free design • Cleaning with CIP, SIP, WIP, COP, OPC and WOP process possible NovoNox cap nut Material: 1.4404 in A4-70 quality Highly polished with up to max. Ra < 0.04 µm Freudenberg washer Material: Elastomer made of 70 EPDM 291, 70 EPDM 253815, 70 EPDM 217676 or Fluoroprene® XP 41 (on request) Shim of 1.4404 NovoNox hexagon head screw with collar Material: 1.4404 in A4-70 quality Highly polished with up to max. Ra <0.04 µm APPENDIX PRODUCT PORTFOLIO MATERIALS RESISTANCE & PURITY ENGINEERING PLASTICS ELASTOMERIC MATERIALS TECHNICAL FUNDAMENTALS INTRODUCTION 75

Pages Overview