GB914105A - Liquid supply system - Google Patents

Abstract

914,105. Centrifugal pumps. DOWTY FUEL SYSTEMS Ltd. June 6, 1961 [June 15, 1960], No. 21057/60. Class 110 (1). In a liquid supply system including a centrifugal pump supplying pressure liquid to an hydraulic load from a low-pressure source, the pump includes a throttle valve balanced with regard to the low pressure for controlling liquid flow into the pump, the throttling portion of the valve being located within or closely adjacent the centre of the pump impeller and the liquid assuming an annular form within the pump, the radial depth of the liquid annulus controlling the output pressure and the central core within the annulus being substantially at the vapour pressure of the liquid. In the centrifugal pump shown, in which the arrangement is such that a central core or cavity substantially at the vapour pressure of the liquid is formed in the liquid at the inlet to the impeller 3 as described in Specification 842,354, the liquid flow is controlled by a throttle valve comprising a cylindrical sleeve 13 which is axially slidable to adjust the effective size of ports 11 in a fixed sleeve 9. The sleeve 13 is actuated by hydraulic pressure applied through ducts 21, 22 to either side of a piston portion 18, a spring 19 urging the sleeve in a direction to uncover the ports 11. Preferably, the sleeve 13 is rotatably driven through gearing 15, 16 so as to reduce its frictional resistance to axial movement. Each port 11 produces a radial stream of liquid within the impeller to reduce the extent of liquid atomization.