GB849386A - Improvements relating to flow control valves - Google Patents

Abstract

849,386. Fluid-pressure servomotor control systems; valves. ELLIOTT BROS. (LONDON) Ltd. (Fisher Governor Co.). Aug. 22, 1958, No. 27060/58. Class 135. A diaphragm valve comprises a dome-shaped seat 20, Fig. 1, having a set of ports 30 communicating with the inlet 14 and a set of ports 32 communicating with the outlet 18 and an elastic diaphragm 38 secured to the valve casing at its edge 44 and stretched so as to fully engage the dome under conditions of no flow. A loading pressure is applied at 52 and may be controlled by inlet pressure at 54. A single pipe line may be provided with two domes and diaphragms, the passages 18 being curved and merging into a single outlet. Eight applications of the valve have been described. In the pressure regulating valve shown in Fig. 9, outlet pressure via 124 acts on the adjustably loaded diaphragm of a pilot valve 126 to allow diaphragm valve loading pressure in 122 to be augmented from the inlet via 120 or vented to the outlet via 124. The valve 126 may be replaced by interconnected self-lapping valves operated by two diaphragms or the valve 126 may be actuated manually or by a solenoid. The twin diaphragm self-lapping valve replacing 126 may be used in a pressure release valve in which case one diaphragm is exposed to inlet pressure and the other diaphragm exposed to outlet pressure or to atmosphere. In two relief valve applications valve 126 is omitted and pipes 120, 122 and 124 contain variable constrictions and are connected to a common damping chamber, or the pipe 120 may contain a diaphragm-operated pressure regulator leading to pipe 122 and then through a variable restriction either to atmosphere or the outlet. Fig. 12 shows the invention used as a cistern dump valve. Normally the diaphragm valve is kept closed by a loading pressure of a column of liquid 168 supplemented by pressure above the liquid in the system 150 acting through the adjustably loaded self-lapping valve 158. For a given height of liquid in tank 150 the pressure above the column 168 is relieved to atmosphere at 160 by the pressure at the foot of the tank acting on a diaphragm via pipe 154. The diaphragm valve is then forced open by inlet pressure equal to the pressure due to the liquid and the pressure above the liquid. The diaphragm valve closes when the pressure in 154 equals the pressure above the liquid together with the spring loading of the self-lapping valve. The diaphragm valve may be used as a cistern supply valve in which case the pressures in the pipes 154, 156 actuate the self-lapping valve 158 to either supply or exhaust diaphragm valve inlet pressure to or from the line loading diaphragm valve.