GB786479A - Pressure regulating mechanism and flow distribution means for enclosures such as aircraft cabins - Google Patents

Abstract

786,479. Fluid-pressure servomotor control systems; valves. GARRETT CORPORATION. Feb. 22, 1954 [March 16, 1953], No. 5104/54. Class 135. An air-flow control valve suitable for application to pressurized aircraft cabins comprises a pressure-responsive control element subject on one side to a control pressure and on at least a portion of the other side to a modifying pressure which is varied in response to flow through the valve. One embodiment is similar to the valve described in Specification 728,480 with the addition of a tube 95, Fig. 2, having an open end adjacent the valve member 34 and communicating through passages 108, 111, 115 with a chamber 57 to furnish the modifying pressure acting on the pressure responsive member 54, 71 in opposition to the control pressure which is effective in a chamber 85. The pressure sensed by the open end of the tube 95 depends upon the flow through the valve. The tube 95 is adjustably positioned by a nut 105, and instead of facing downstream as shown, it may face upstream. Alternatively, the tube 95 may be fixed to the valve member with its open end facing the valve seat 37. In another embodiment, the flow sensing tube opens adjacent one of the closure members of a double-beat valve of the kind described in Specification 652,423. The valves may be used in a system in which a cabin 11, Fig. 1, is pressurized by a supercharger 12 and discharges through chambers A, B to atmosphere. Valves 16, 26 control the connection of the cabin 11 with the chambers A, B respectively to maintain the rates of flow through those chambers in fixed proportion. .A pressure control unit 19, e.g. as described in Specification 718,674, is common to both valves 16, 26. The pressure in chamber B is controlled by an outflow valve 21 under the control of a regulator 23. In another embodiment a valve member 179, 182, 202, Fig. 6, is subject on its upper side to control pressure in a chamber 215 and on its lower side to pressure in a chamber 195 which is connected by a pipe 198 to a point 196 in a throat of the valve so as to sense a pressure related to flow. The chamber 215, which has a bleed 217 to atmosphere, is connected through a port 216 to pressure-responsive control devices comprising a low-differential control 240, an isobaric control 241, a climb and dive control 242, which controls the rate of change of pressure, and a high differential control 243. These devices actuate valves which control flow of air through an opening 237 from the cabin to the chamber 215. Instead of the main valve being combined with the control devices as shown it may be connected to the control chamber of another outflow valve or to a separate regulator unit.