| 摘要 |
<p>1498442 Valves POSI-SEAL INTERNATIONAL Inc 2 July 1975 [2 July 1974 20 May 1975] 27868/75 Heading F2V The seal between a valve closure member 12 and a fixed body 1 is provided by a thin, upstream facing, annular, interference fit lip 28. As shown closure 12 is a butterfly disc and lip 28 is provided on a ring 7 retaining an elastomeric or metal sealing ring 9 within a groove in body 1. An elastomeric backing ring 10 may also be provided. Sealing is assisted by upstream pressure acting within the groove. Ring 7 may be of carbon steel having a lower coefficient of expansion than the stainless steel valve disc 12, so that sealing improves with increasing temperature. In a modification lip 28 may be provided on disc 12, in which case the lip may be of ceramic material.</p> |
