GB1338486A - Rotary positive-displacement pumps - Google Patents

Abstract

1338486 Rotary positive-displacement pumps TRW Inc 11 May 1971 [5 Nov 1970] 14301/71 Heading F1F In an hydraulic double-acting sliding-vane type pump having a rotor 20 with vanes (not sHown) co-operating with a cam ring 22, pairs of outlet ports 67 in fixed plates 60, 160 communicate with an outlet bore 41 by way of an orifice 50 in an axially-movable spring-loaded valve-plate 40. The plate 60 comprises sections 61, 62 secured to each other, an annular land 76 separating a chamber B from an annular by-pass passage 79, a port 71 communicating with a space between a fixed shell 23 and the cam ring, and a passage 73 in register with a port 72 through which fluid enters said space from a reservoir (not shown) surrounding the shell. Pairs of inlet ports 68, 69 in said plates communicate with said space. When the pressure in the chamber B lifts the valve plate, the flow of fluid from the passage 79 to the port 71 creates suction at the port 72 to supplement the flow to the ports 68, 69. The valve plate is furnished with a pressure-relief valve 52, 53, 54, 56, 57 in register with an opening 58 in the shell. Pressures above and below the vanes are balanced by passages 67a, 69a in the plates 60, 160. An annular relief 78 to ensure sealing contact between the land 76 and the valve plate may be surrounded by an outer shield on said plate to minimize leakage therethrough when said plate lifts, Fig. 5 (not shown).