GB1055158A - Improvements in or relating to fluid control valves - Google Patents

Abstract

1,055,158. Valves. M. H. GROVE. Nov. 4, 1963 [Nov. 13, 1962; Jan. 23, 1963], No. 43475/63. Heading F2V. A high-pressure seal e.g. for pressures above 200 p.s.i. is provided between a valve body and a closure by an annular seal member of relatively hard resilient material nylon which surrounds a fluid passage and which has an annular insert of softer resilient material, e.g. synthetic rubber of 60 to 80 Durometer hardness, bonded within a recess therein and which engages the closure. Synthetic rubber insert 32 is moulded within machined nylon seal member 21 which is assembled as a shrink fit from boiling water upon carrier ring 22. The seal is urged into contact with a gate valve closure 11 (Fig. 1, not shown), having a port 16, by a series of springs 23 circumferentially spaced around a mounting ring 17, interfitting a bore 18 machined in the valve body, within which a flange 29 of seal member 21 is a snap fit to limit the displacement thereof by engagement with a shoulder 31. A sediment guard 24 comprises a split ring inserted in an annular recess 26 of the ring 17. The insert 32 is disposed within and projects from a seal member groove with tapered side walls which, as the seal member is urged towards the closure with increasing force, deflect inwards to increase sealing compression thereupon. A secondary seal is effected by the carrier ring 22 in the event of failure e.g. by fire, of seal member 21. The soft insert 32 exerts a wiping action upon the closure 11. The seal is effected at a diameter smaller than that of the bore 20 exposed to upstream pressure, which enhances the sealing effect. In a wedge gate valve (Fig. 12, not shown), a soft rubber insert 66 is retained within an annular seal member 63 screwed into the valve body.