| 摘要 |
1,221,620. Valves. AUTOCLAVE ENGS. Inc. 13 Oct., 1969 [11 July, 1969], No. 50197/69. Heading F2V. A valve comprises a closure member 9 having a face 10 to co-operate with a seat 7, mounted on an inner stem 8, an outer stem 13 slidably mounted on the stem 9 and having a face 15 adjacent a back face 11 of the member 9, an annular plastic seal abutting the faces 11 and 15 which are biased into contact by a spring 17, a packing 22, 23, 24 sealing the stem 13 and the valve housing, the outer stem being screwthreaded at 21 to a mounting sleeve 26 so that when it is rotated by a handle 30 it carries the inner stem 8 and closure member 9 to the seat 7 until they abut, and further movement deforms the plastic seal into contact with the wall of the valve body. In the Figure, the plastic seal is formed by an inner rubber ring 19, and an outer P.T.F.E. ring 20. In the closed position the seal is assisted by fluid pressure acting on the upper face of the ring 20. The face 10 of the closure member 9 can be conical, paraboloidal, or spherical.
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