GB789241A - Improvements in and relating to an electromagnetic valve - Google Patents

Abstract

789,241. Valves controlled by auxiliary valves. DUBOIS, R. C. July 18, 1955 [July 19, 1954; July 5, 1955], No. 20769/55. Class 135. In a valve comprising a piston 8, Fig. 1, carrying a main closure member 7 and controlled by a pilot valve 15 which is actuated by an electromagnet 26, the piston and closure member are slidable on a tubular element 14 which forms part of a passage for fluid under the control of the pilot valve. The inlet 3 communicates through a restricted passage 12 with a chamber 9 which also houses a spring 19 acting on the piston 8 in the valve-closing direction, whilst the chamber 9 also communicates through ports 17 and the pilot valve controlled port 20 with the tubular member 14 which has openings 16 leading to the outlet 4. When the electromagnet is energized the pilot valve 15 is opened to allow fluid in the chamber 9 to escape to the outlet, thereby lowering the pressure above the piston 8 to cause the inlet pressure to open the main valve. In a modification, the pilot valve is arranged at the end of the tubular member 14 that communicates with the outlet 4. In another modification, the piston and main valve member are of hollow formation and the openings from the tubular element to the outlet are screened so that the flow past the main valve seating induces a lower pressure in the chamber above the piston. Instead of the pilot valve opening on energization of the electromagnet it may be arranged to close. Also, the tubular element, instead of being fixed, may be operable by the electromagnet whilst the member 15 is fixed. In a further modification, an additional valve member 62, Fig. 5, is attached by a tube 68 to the valve member 7 and is arranged to connect the outlet 4 with an exhaust when the valve member 7 is closed. The outlet from the pilot valve 15 through the tubular element 14 and ports 71 passes through a chamber 66 below the second valve member 62 and thence through an adjustably restricted orifice 72 to the outlet 4. By adjusting the orifice 72 the rate of operation of the main valve assembly may be controlled.