Improvements in or relating to valves

摘要

870,882. Valves. GLOSTER AIRCRAFT CO. Ltd. April 23, 1958 [April 23, 1957], No. 12898/57. Class 135. In a vent valve for an aircraft fuel system a first chamber 5a is defined by the top plate 2 and a combined diaphragm and disc valve unit 3, 12 pressed against a seating by a loading spring 16, the diaphragm 3 also forming the upper wall of an annular vent chamber 5b surrounding the seating and communicating with a vent outlet 6, the disc valve 12 having a central aperture through which passes a needle valve 10 attached to a float 4 and controlling the opening 13 of a vent passage 14 communicating through a non-return valve 15 with the vent outlet 6. The disc valve unit consists of an upper perforated plate 12 against which an unapertured disc 17 is pressed by a spring 18. If float 4 falls valve 10 opens passage 13, 14 allowing the pressure above the diaphragm to fall to atmospheric or other design pressure, under which conditions a predetermined force applied to valve 12 against spring 16 enables the diaphragm to lift for outward venting. When the float rises and valve 10 closes inlet 13 pressure is equalized above and below the diaphragm and the latter is reseated. The effective area of the upper diaphragm surface being greater than the lower increase of pressure increases the sealing force. Inward venting can occur whether or not opening 13 is closed by valve 10, if the pressure in outlet 6 reaches a predetermined value greater than that on the lower surface of the diaphragm, non-return valve 15 preventing inward flow through passage 14. Float 4 is weighted so that valve 10 closes opening 13 during inverted flight.