GB1143007A - Pressure control valve - Google Patents

Abstract

1,143,007. Fluid-pressure servomotor systems. WESTLAND AIRCRAFT Ltd. June 21, 1967 [June 23, 1966], No.28238/66. Heading G3P. A valve for controlling flow through an opening includes a valve seat 3, a pressure chamber 18 comprising a movable valve member 10 having a flange 12 extending towards the valve seat, a flexible sealing element 16 connecting the valve member to a wall member 6 supported centrally within the valve member, and resilient means 17 urging the valve member in an axial direction relatively to the valve seat, the valve member being slidably supported in a ducted member 5. The valve member has a hollow stem 13 communicating with ducts 7, 8 in which the pressure may be regulated by a relay such as that shown at 19 and by altitude and differential pressure limiters 20, 21. In the preferred embodiment, the valve controls the pressure in an aircraft cabin and the relay is subjected to cabin pressure (Pc) and to a low-pressure (Pt) obtained from the throat of a Venturi which may form the outlet from the seat 3. Air flowing into the cabin through the Venturi causes the valve to move into operating position against the spring 17, subsequent operation being controlled by the differential pressure on the relay 19. The spring 17 may be arranged to close the valve if a pressure higher than that in the cabin is connected to the relay 19. A pair of elements or a single preformed element may replace the element 16 to provide a flexible annular chamber communicating with the cabin through a series of holes in the skirt of the valve. The pressure in chamber 18 may be obtained from a pump or from the cabin supply duct.