GB812812A - Improvements in or relating to multi-stage pumps - Google Patents

Abstract

812,812. Radial cylinder pumps. WOODCOCK, F. H. June 20, 1955 [July 2, 1954], No. 19386/54. Class 102(1). [Also in Group XXVI] A fluid pump has two stages, the first stage comprising a pump of the sliding vane type and the second stage comprising pistons mounted on the inner ends of the vanes reciprocating in radial cylindrical bores in the rotor. In the embodiment illustrated sliding vanes 30 co-operate with a track ring 29 which is the inner race of a needle roller bearing 28 and rotates with vanes 30 which are urged outwards by spring rings 65. Fluid enters suction spaces 35 from an inlet passage 34 and is discharged from pressure spaces 37, through an outlet port 38 and through a passage 39 into two inlet passages 42 in a stationary pintle member 40 which is a running fit in a bore 41 in the rotor shaft 19. The fluid then passes through an arcuate inlet port 46 to cylinders 33 when it is acted upon by pistons 32 and discharged through an arcuate port 47 into a passage 48 in the pintle communicating with a discharge connection 49. The capacity of the sliding vane first stage pump is greater than that of the second stage and accordingly a relief valve 50 is placed in a passage 51 leading from the outlet port 38 of the first stage pump to a low pressure discharge connection 52. A ring 26 containing the bearing 28 is pivoted in a bore 15 in the pump casing about a pin 61 to vary the eccentricity of the track 29 with respect to the rotor 12, the eccentricity being controlled by a discharge pressure actuated piston 56 and an adjustably spring loaded piston 59 so as to decrease the pump capacity on increasing discharge pressure.