GB730965A - Improvements in or relating to control valve devices - Google Patents

Abstract

730,965. Valves under control of auxiliary pilot valves. BRITISH MESSIER, Ltd. April 2, 1953 [April 3, 1952], No. 8595/52. Class 135. A control valve in a fluid-pressure circuit is moved in both directions by two fluid-pressure actuators, there being a throttled supply and a throttled exhaust passage to and from each of the actuators, and the valve is caused to move by varying the relative degree of such throttling under electromagnetic control. Pressure liquid from a supply 15 is applied to one end 14 of a jack in order to load it, and the liquid also flows past restrictions 34, 35 into chambers 32, 33 where it can act on the equal end faces of a piston valve 20. The central land of the valve controls a port 24 leading to the other end 17 of the jack so that, when the valve 20 moves, it either places the end 17 in communication with the pressure supply through a port 23 or exhausts the end 17 to a line 29 through a port 25. The pressure liquid in the chambers 32, 33 can flow out past restrictions 38, 39 to opposed nozzles 40, 41, and the discharge areas of the nozzles are differentially controlled by a ball 50 carried by the armature of a polarized electromagnet 45. If, for example, the electromagnet is energized to cause the ball 50 to obturate nozzle 41, a back pressure will build up in chamber 33 and valve 20 will move to the left to place the end 17 of the jack in communication with the exhaust, and, owing to the differential areas of the faces of the jack piston, the latter will move to the right. In moving to the left, valve 20 will close off restricted passage 38 and pressure will also build up in chamber 32. If an electric feed-back is taken to polarized electromagnet 45, the speed of the jack will be a function of the current flowing in the electromagnet.