| 摘要 |
1275542 Valves HILLS-McCANNA CO 2 Jan 1970 [6 Aug 1969] 196/70 Heading F2V In a butterfly valve the seat 64 co-operating with a spherical surface 60 on a rotary disc 50 is formed of a flexible sheath 68 having a bulbous portion 70 enclosing a filler 80 and two marginal edges 74, 76 which are clamped between concentric lands 112 and grooves 114 on the body part 112 and a ring 114. The portion 70 is positioned within a groove 66 to form spaces on each side into one of which pressure fluid enters, in operation of the valve, to force the portion 70 into sealing contact with the opposite side wall of the groove and the surface 60. The disc is rotated by a handle on shaft 52 and may be locked in position by pivoted lever 126 on the handle entering one of a number of notches 130 in the body. The sheath may be an elastomer, e.g. polyvinylidene fluoride, polyimide, monochlorotrifluoroethylene, P.T.F.E. or polythene and filled with a ring or rubber, urethane, plasticized polyfluoroelastomers or an annular helical spring. Alternatively the sheath may be of metal and filled with an annular helical spring which may be surrounded by asbestos, or a resilient or fluent composition. A one piece sealing ring and flange may be formed from ethylenepropylene polymer, methane, a fluorinated elastomer, or chlorinated sulfonated polyethylene. In a modification of valve the closure member is a rotary sphere. |
