| 摘要 |
A vacuum system pipe coupling 20, particularly for use in an exhaust system of a vacuum system carrying a corrosive gas such as fluorine from semiconductor processing equipment, includes a first coupling member 24 and a second coupling member 28, and a seal system 32 positioned to seal between first and second coupling members 24, 28, comprising an inner seal 36 and an outer seal 38, and preferably a spacer between the seal elements or integral with a seal element. A securing system (34, Figure 3) releasably secures coupling members 24, 28. Coupling member 24 has a flow passage 40 conducting a pressurised gas, preferably a substantially inert gas such as nitrogen, to a space 42 between seal elements 36, 38, shielding outer seal element 38 from fluid in coupling 20 if inner seal element 36 fails. Outer seal 38 may comprise a fluoroelastomer and inner seal 36 may comprise a substrate of a fluoroelastomer and a sleeve of a perfluoroelastomer. |
