GB705140A - Plunger controlled check valve - Google Patents

Abstract

705,140. Check valves. ELECTROL, Inc. June 11, 1952 [June 12, 1951], No. 14760/52. Class 135 A check valve which may also be operated manually or mechanically from outside the valve casing 11 comprises a valve member 30 spring- loaded towards a valve seat 31 and having a valve stem 53 passing through the valve seat and slidably engaging a piston 45 itself slidable in the valve casing, the piston having substantially the same effective area as the valve member and being urged by fluid pressure against the valve stem to unseat the valve member with a force substantially the same as that exerted by fluid pressure on the valve member in a direction to close it so that the piston is easily movable to unseat the valve member by means of a plunger 35 operable from outside the valve casing 11. The casing 11 has inlet and outlet bores 15, 16 connected respectively by angledrilled passages 17, 18 to a bore 19 formed with a seat 21 for a flanged sleeve 20 in which the piston 45 slides. The sleeve 20 has one or more ports 29. The flanges 23, 24 of the sleeve 20 are grooved to receive rubbery rings 25, 26 in sealing engagement with the bore 19. The valve stem 53 has a ported extension 52 slidable in the piston 45 which also has a grooved flange 50 with a sealing ring 51. Outlet pressure has access to the space 44 to the right of the piston through passages 55, 56, an annular chamber 28 and notches 43 between the end of the sleeve 20 and a partition ring 42 held in the casing 11 by a screwed sleeve 39. A stem 46 on the piston 45 passes through a packing 47 and carries a cup 48 pressed by a spring 49 against the plunger 35 which is retained in the casing by a flange 38 engaging a shoulder 41 in the sleeve 39.