GB939661A - Improvements in fluid flow control valves - Google Patents

Abstract

939,661. Valves. BLACK AUTOMATIC CONTROLS Ltd. June 23, 1960 [March 25, 1959], No. 10296/59. Class 135. Pressure fluid supplied to an inlet 26 flows through the bore of a control sleeve 3, ports 24 and an annular groove 25, both in the wall of the sleeve 3, a recess 12a in a piston 12, ports 23 leading from the recess 12a, a chamber 19, and a fixed orifice 6 in a pipe 7, to an outlet chamber 20. So long as there is a flow of fluid through the orifice 6 there is a pressure difference in chambers 19, 20, and hence across the piston 12, which urges the latter against a loading spring 10, thereby altering the degree of throttling of the groove 25 by a bush extension 18 of the piston, and thus varying the pressure difference across the latter until a new equilibrium position of the piston obtains. Any change in demand for fluid from the outlet chamber 20 will result in further movement of the piston to maintain a constant flow at the outlet. The sleeve 3 may be manually adjusted. In various modifications, the piston may be replaced by a diaphragm or bellows; the valve outlet may be connected directly to the pipe 7 instead of the chamber 20. The sleeve 3 may be dispensed with and the ports 24 and groove 25 formed in the wall of the valve casing 11, the groove co-operating with a land of the piston; in this case the spring sits upon an adjustable abutment.