A new or improved fluid proportioner applicable, for example, to aircraft fuel systems

摘要

702,746. Rotary pumps. SELF-PRIMING PUMP & ENGINEERING CO., Ltd., and McKEAN, J. A. Oct. 4, 1951 [Oct. 5, 1950], No. 24385/50. Class 110 (2). [Also in Group XXIX] A fluid proportioner comprises two or more sliding vane flow controlling devices which consist of a hollow stator 16, Fig. 2, having an internal curved surface, a rotor 30 within the stator and positioned relatively to the curved surface to leave a space having inlet and outlet ports 23, 24, respectively, the sliding vanes in the rotor being arranged to move fluid from the inlet to the outlet on rotation of the rotor, wherein the rotors are rotated in unison, the controlling devices are allocated respectively to the several fluids to be proportioned and have a ratio or ratios of throughput corresponding to, or adjustable to correspond to, the fluid proportions desired. As shown the proportioner comprises three devices controlling flow from three fuel tanks in an aircraft wing. The rotors 30 are mounted on a shaft 6 driven by an electric motor through a free wheel and driving a gear pump 71, Fig. 3. The inlet 13 of each device is connected to a respective tank and the outlets 14 are interconnected and lead to the engine pump: Each tank has a pump which supplies fuel to its respective inlet and should any pump fail, the rotor of that device will act as a pump. The stator 16 of each device is adjusted axially by nut 37 to cause flow in the desired proportions, the free wheel permitting the liquid to drive the rotors faster than the motor. A float 50 in each inlet controls a valve 55 having connections 75 to the outlet of pump 71, 76 to a bore 73 connected to all the inlets 13 via non-return valves and hence supplied by whichever inlet has the highest pressure, 77 to a chamber 45 above an annular bellows 40, and 79 to a chamber 67, Fig. 7. The bellows 40 which is open to atmosphere or tank pressure via bore 41 is connected to the stator 16 and contains a spring 44 urging the stator to cut off flow. Float 50, when raised, positions valve 55 to supply inlet pressure to the chamber 45 to collapse the bellows, but if the liquid level drops, e.g. due to emptying the tank, the float falls and' causes valve 55 to connect chamber 45 to exhaust whereby the bellows expand and raise the stator to prevent air being drawn through to the engine since the rotor will continue rotating by action of the other rotors. Each rotor has a by-pass 60 controlled by a valve 61 held closed by the pressure in the chamber 67 acting on a bellows 66. Should the rotors jam, pump 71 will stop and the pressure in chambers 67 will fall permitting valves 61 to open and pass fuel to the outlet. Each chamber 67 is connected to the pump outlet when the float is raised. When any float falls the bore 73 is connected to the appropriate chamber 67 and pressure is thus maintained to hold the valve 61 closed.