| 摘要 |
<p>A valve seal (8, 9) particularly suitable for cryogenic service comprises a hollow generally cylindrical member fabricated from a material which under cryogenic service conditions is flexible but substantially incompressible. Spaced annular grooves (17, 19) are formed on the inner wall of the member and a further groove (18) is formed on the outer wall between grooves (17, 19). The opposite grooves (17, 19 and 18) overlap slightly to form a "concertina" like wall cross section. A tapered seating surface (13, 14) is provided to engage the outer surface of a valve ball (7). In service, annular grooves (17, 19 and 18) provide a degree of resilience in a material otherwise incompressible under service conditions. </p> |
