GB630968A - Improvements in or relating to automatic flow regulating valves - Google Patents

Abstract

630,968. Fluid-actuated valves ; hydraulic transmission of power. SHIELDS, R. (Vickers Inc.). Aug. 13. 1946, No. 23919. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 29, 1946.] [Classes 69 (ii) and 135] In order to facilitate the mass production of several types of flow-regiilating valves, in which a pressure compensating valve controlled by the pressure drop across an adjustable throttle maintains constant the flow through the throttle, a basic design of valve body is adapted to be used without modifications or with the addition of various bores and passages in the manufacture of the several types of valve. The basic designs of valve body, 42, Fig. 1, is provided with two external ports 56, 60 respectively, connected to the exhaust of a hydraulic motor 26 and an oil reservoir 12, and the liquid flow between these ports is regulated by a piston valve 92 integral with an actuating piston 84 the faces of which are subjected through passages 82, 52 to the pressures on each side of a manually adjustable throttle valve 63, and thus the piston valve 92 functions to prevent the rate of flow of the exhaust liquid and therefore the speed of the motor exceeding the value determined by the setting of the throttle valve. The basic design may be modified by the addition of a bore 168, Fig. 5, accommodating a non-return valve 174 and a passage 135<SP>1</SP>, thus providing an alternative fluid path between the port 56, communicating with one end of the motor, and the port 60 which may be connected by a valve 20 either to the reservoir 12 or to a pump 10. When the port 60 is connected to the reservoir the flow of exhaust fluid from the motor is regulated by the valve 92, but when the port 60 is connected to the pump, pressure fluid passes through the non-return valve and gives a quick-return movement to the motor. In a modification the basic valve body is provided with an inlet passage 128, Fig. 4, connected to the pump 10 and communicating through the adjustable throttle with the port 601, a passage 135 communicating with a chamber 95 enclosed by the piston 84<SP>1</SP>, and a bore 132, one end of which communicates with the port 56<SP>1</SP> and the other with the passage 135. The ports 561, 601 are respectively connected to the reservoir 12 and one end of the motor 26 and a pilot relief valve 142 is mounted in the bore 132. In operation when the flow from the pump across the throttle to the motor becomes excessive, the pressures on each side of the throttle acting on opposite faces of the piston 841 move the piston and actuate a piston valve 901 which byepasses the excess fluid through the port 56<SP>1</SP> to the reservoir. The pilot valve 142 is adapted to be opened by excessive fluid pressure in the system to suddenly exhaust the chamber 95, thus causing the unbalanced pressure on the piston 84<SP>1</SP> to move the piston and to open the valve 901. Specification 399,609 is referred to.