GB859562A - Improvements in or relating to valve apparatus for controlling fluids - Google Patents

Abstract

859,562. Valves. SISKOL MACHINES Ltd. May 6, 1957 [May 4, 1956], No. 13878/56. Class 135. A valve apparatus for controlling the flow of one fluid is controlled by the flow of another fluid through the medium of a pressure-sensitive actuating means for a gate type controlvalve operable in the duct for the controlled fluid and independent of variations in the pressure of the controlled fluid. The apparatus comprises a circular hollow body 10 having therein a fluid pressure chamber 13 divided by a flexible diaphragm 14 to provide a high-pressure compartment 15 and a low-pressure compartment 16, the diaphragm being urged towards the high-pressure compartment by a spring 17 and carrying at its axis a tubular valve member 18 in sliding engagement with the walls of the pressure chamber. A duct 24 having an inlet 25 and an outlet 26 is provided through which the controlled fluid flows. The duct is interrupted transversely by a guide bore 19 so that the tubular valve member 18 can be moved across the duct in closing engagement therewith. A further duct 29 having an inlet 30 and an outlet 31 is provided for the controlling fluid. A centrally orificed disc 32 is located at the inlet of the duct 29, the pressure on either side of the disc being sensed by the diaphragm 14 via passages 33 and 34. Instead of the orifice a Venturi may be provided. In operation, as fluid is allowed to flow through the duct 29 the highpressure compartment 15 senses the pressure upstream of the orifice 32 and the low-pressure compartment senses the downstream pressure to cause a pressure difference across the diaphragm to move it against the spring 17 and so slide the tubular valve member 18 to open the controlled fluid duct 24. Due to the fact that the valve member 18 is tubular and open at both ends it is not subject to any variations in pressure in the controlled fluid duct 24. The lower end of the valve member 18 opens into a sump 27. In another embodiment the tubular valve member 18, when in the open position, admits passage therethrough of the controlled fluid and thereby functions as part of the duct for the controlled fluid. In both embodiments the diaphragm 14 may be replaced by a piston.