Ring or O-ring seal, for low and medium pressures at metal/plastics pipes or pipe flanges, has outer layers of unsintered and expanded polytetrafluoroethlyene and an inner layer between them of sintered polytetrafluoroethlyene

摘要

The seal for metal or plastics pipes or pipe flanges, as a ring or O-ring seal with a ring (6) around a center opening (5), has two outer layers (10a,10b) of unsintered and expanded PTFE and at least one inner layer (12) between them of sintered and skimmed PTFE. The inner layer has a grid structure with openings or weakened zones. The inner layer can also be of fluorinated ethylene propylene (FEP).