FIRE SAFE CLOSURE RING SEAL SYSTEM FOR FLUG VALVES

摘要

a seal system comprises a non-flat cross-section, fire resistant compressibl e ring (44) and an annular pocket (42) formed between two engagting surfaces (36, 38) of a pressure vessel such as a plug valve (10). The pocket is forme d by providing a chamfer (40) in one such surface (38) which is then enclosed by the other such surface (36). The ring is compressed within the pocket to substantially fill the pocket upon mating of the two surfaces.