GB1147262A - Variable displacement high speed rotary sliding vane pump - Google Patents

Abstract

1,147,262. Rotary pumps. BATTELLE DEVELOPMENT CORP. Jan.24, 1967 [May 12, 1966], No.3523/67. Heading F1F. To vary pump displacement in a rotary sliding vane pump of twin abutment type, operating particularly at high-pressures, e.g., 2000-8000 psc and high speeds, e.g., 20000-22000 rpm, a cam-track 90, Fig.2, against which the tips of vanes 61 slide comprises a pair of fixed camtrack members 95, 97 and a pair of radially movable cam-track members 107, 109 interconnected by overlapping sliding bridges 101. Each fixed member includes a curved cam-track 91, Fig. 3b, having short straight tangential, end portions 119 and each movable member a curved cam-track 105 again having short straight tangential end portions 119. Tangs 113 on the fixed and movable members co-operate with slots 115 in the bridges 101 so that when the movable members are moved by pistons 169, slidable in chambers 165 having ports 181, 183 to admit and discharge pressure liquid to and from opposite sides of the piston, the bridges move with the movable members. The inlet ports to the pumping chambers are provided by spaces in the bridges. The radii of the curved cam-tracks 91, 105 are preferably the same and in the "no pumping" position centred at 123 on the rotor axis. To balance pressure forces on the rotor 59 the movable members 107, 109 are maintained equi-distant at all times from the axis 123 by an equalizer plate (193, Fig. 1 not shown) positioned between a pressureloaded end plate (71) and the casing cover (43). The plate (193) which is free to rotate, is provided with a pair of diametral slots (197, Fig.6 not shown) slidably mounting sliders (199) provided with pins (201), each of which engages one of the movable members. Pressure in the discharge ports 39 is transmitted to act on the rear face of the pressure-loaded end plate (71) which is urged towards the rotor and against a casing shoulder to give effective sealing and sufficient clearance for rotor operation. To reduce the forces necessary to move the pistons 169 and the movable members 107, 109, a balance piston 137 is secured to each movable member. The spaces behind the balance pistons are connected through ducts 159, 157 to the pump discharge ports 39 so that pump discharge pressure acts on both faces of the pistons. The vane tips are lubricated by a thin film of oil trapped between the tips and the cam-track 90. To hydrostatically and hydrodynamically balance the vanes 61 each vane is provided with a pivoted tip 203, Fig.7, formed with a step 209 and slides in a corresponding stepped slot with the area beneath the step 209 located on the leading side of the vane greater than the area under the vane 217.