GB512641A - Improvements in or relating to hydraulic operating mechanism for valves and other parts having a to and fro movement - Google Patents

Abstract

512,641. Hydraulic apparatus; valves. SHERLOCK, J. E., and BRITISH THERMOSTAT CO., Ltd. March 10, 1938, No. 7520. [Classes 69 (ii) and 135] Hydraulic operating mechanism for valves or other parts having a to and fro movement of the kind comprising a piston or the like and a pump arranged to build up hydraulic pressure upon the piston or the like for moving the controlled part in one direction, a return spring or weight moving the controlled part in the opposite direction when the hydraulic pressure is released, is characterised in that the torque reaction of the pump controls a release valve so that the release valve is closed when the pump is working and is open when the pump is idle. A valve A is operated in one direction by a bellows 1 against the action of concentric return springs 9. A gear pump 14 having an inlet 16 is immersed in a reservoir 4, and driven by an electric motor 26. The pump body is pivotally mounted by a pivot pin 18 coaxial with the driving shaft 19, said pin being hollow and serving to convey liquid from the pump outlet to the interior of the bellows. An arm 20 secured to the pin 18 is, when the pump is inoperative, held by a spring against a stop, so that a part 21 carried by the arm is free of a hole 23 which thus places the interior of the bellows in communication with the reservoir. When the motor 26 is started, the pump body rotates until the arm 20 abuts against another stop in which position the part 21 closes the hole 23 to permit the establishment of pressure in the bellows. The motor 26 may be controlled by a thermostatic or other automatic switching device or by a remote hand operated switch. A screw 11 and bell-crank 12 serve for hand-operation of the valve A.