Patent GB-825373-A (GB)
Title: Improvements in or relating to valve devices for controlling the flow of liquids
IPC: B64F1/28
Filed: 1956-04-16
Abstract: 825,373. Filling and emptying tanks. FLIGHT REFUELLING Ltd., and MARRIETTE, G. F. March 25,1957 [April 16, 1956], No. 11529/56. Class 21. [Also in Group XXIX] A liquid storage tank, e.g. an  aircraft fuel tank, is filled and the contents subsequently withdrawn for use through a common pipe line by a valve device which comprises a valve body formed with a through flow passage, two valve members for controlling said passage, and either of which when opened, allows flow of liquid through the said passage, one of said members being urged towards its open position by liquid flowing in one direction through the valve body and the other being urged towards its open position by liquid flowing in the other direction through the valve body, a control housing, a piston slidable in the control housing and adapted to apply a closing thrust to one valve member when urged in one direction and to apply a closing thrust to the other valve member when urged in the other direction, and means operable by liquid level responsive means in the tank to control a pressure differential across the piston. As shown, the valve device is connected at one end both to a fuel supply coupling 16 and to an aircraft engine 17, and at the other end to the aircraft fuel tank 19 which has high and low level floats 21 and 22 respectively. The control housing 23 in valve body 10 forms therewith an annular portion 11 of the through flow passage and this housing engages over a spring loaded tubular valve member 25 having a closure head which obturates a seat opening 24, the member 25 itself providing a seating 28 for a second tubular valve member 31 carrying a closure member 29 and having a coaxial orifice 39 therethrough. The second valve member 31 slidably engages in the first valve member 25 and extends into the control housing wherein it slidably engages the piston 35. A control chamber 38 on one side of the piston communicates with the annular flow passage 11 through a hole 40 in the control housing, whilst a control chamber 37 on the opposite side of the piston is in communication through orifice 49 with that side of the through flow passage next to the tank. Chamber 37 also communicates with the other end of the flow passage, next to the supply coupling. firstly through a solenoid-operated valve 44 which is spring-closed when the solenoid is de-energised by the breaking of electrical contacts 49, 50 on rising of the high level float, and secondly through a pipe 51 via a non-return valve 56 and a control valve 54 which is closed on falling of the low level float. When fuel is supplied through the device to the tank, it passes from the annular flow passage through ports 34 in the outer valve member and unseats the inner valve member 31, a manual electric switch 48a in the solenoid circuit being closed and solenoidoperated control valve 44 being open and the pressures on opposite sides of the piston being balanced through hole 40. On the fuel reaching the high level, closure of control valve 44 causes pressure in chamber 37 to fall through orifice 39 and piston 35 moves to close the inner valve member. When fuel is being withdrawn from the tank to supply the engine manual switch 48a is opened ; both the valve members 25 and 31 move to the left and on the fuel reaching the low level control valve 53 closes and the consequent build up of pressure in chamber 37 through orifice 39 moves the piston to the right to close the flow passage.