GB1302984A - - Google Patents

Abstract

1302984 Rotary pumps TRW Inc 19 April 1971 [8 June 1970] 22428/71 Heading F1F A rotary sliding-vane pump 10 includes a flow control device comprising a pressure plate 23 and an axially movable valve plate 30 one of the plates having a circumferentially continuous shoulder 52 defining between the plates 23, 30 an inner outlet zone 53 into which the pump delivers via outlets 47, 48, and an outer inlet zone communicating with the pump inlets 44, 46, the outlet zone 53 connecting, via a variably restricted orifice 62 in the valve plate 30, with a delivery zone 39 behind the plate 30, the pressure drop across the orifice 62, Fig.7, producing on the valve plate 30 a force, which, when it exceeds the force due to a spring 84, moves the plate 30 to by-pass fluid from the outlet zone 53 via the shoulder 52 to the inlet zone 54. The vanes 34 are substantially cylindrical with axially extending seals, and are biased by springs 36 against a casing ring 22 which defines a pair of abutments, Fig. 2 (not shown). Fluid flowing through the orifice 62 reaches the delivery zone via an annular space 63 and a passage way 86. The area of orifice 62 is controlled by a plunger 66 having a tapered shoulder 68 and movable axially by the pressure of fluid in zone 53 acting against a spring 74 located in a space 88 connected by a passage 89, Fig.1, with the inlet zone 54, movement of the plunger 66 ausing a rod 79 to unseat a ball 83 to connect the delivery zone 39 via passageway 86, opening 91, ball 83, space 88 and passage 89 to the inlet zone 54.