GB709813A - Inlet control means for air or other gas compression or vacuum pumps - Google Patents

Abstract

709,813. Fluid-pressure servomotor-control systems. HYDROVANE COMPRESSOR CO., Ltd. May 8, 1952 [May 28, 1951], No. 12433/51. Class 135 Means for controlling the admission of air or other gas to an air or other gas compression or vacuum pump, comprising the combination of a spring-loaded gas-inflow controlling member operable by a variable liquid pressure, and a spring-loaded valve operable by the said pressure for controlling the action of the said member. As shown, the air inlet passage m, Fig. 1, to the pump is supplied from passage k and controlled by the inflow controlling member formed as a piston valve c, inside which is a check valve e seating against the air supply passage k. The pressure of the sealing oil of the pump is applied through port n and acts on a piston i which, at a predetermined oil pressure moves against spring j to open passage p whereby the oil acts on the piston valve c to move it to close the passage m against a spring d. When the pump delivery pressure falls, the oil pressure also falls, and the piston i returns to its initial position, thus permitting oil in passage p to flow through a passage o into the pump. In another arrangement, a valve e', Fig. 3, controls communication between passage k and inlet m and has a stem r slidable in an inflow controlling member formed as a piston s loaded by a spring t. Thus, an increase in pump delivery pressure moves piston i to open passage p whereby oil moves piston s to engage shoulder x on stem r and move valve e' towards closed position. In yet another arrangement, the inlet control valve is a lift valve actuated by a single-acting piston.