GB902523A - Improvements in fuel flow proportioners - Google Patents

Abstract

902,523. Mixing flowing liquids proportionately. HOBSON Ltd., H. M. May 9, 1960 [May 28, 1959], No. 18240/59. Class 86. [Also in Groups XXVI and XXIX] A fuel-flow proportioner for delivering fuel to a common outlet 12, Fig. 3, from two tank systems in an aircraft comprises a positive displacement metering pump 13, 14, Fig. 2, connected to each tank system, a fluid-pressure operated motor 17, 18 to drive all the units at the same speed, a device 20 responsive to the pressure in the common fuel outlet for controlling the flow of fluid to the motor in such fashion as to maintain that pressure at a predetermined value, and a device 27 for maintaining equal supply pressures to the pumps. In the preferred embodiment, two pumps are arranged at opposite sides of the motor 17, 18 which has a control valve 20 for a compressed-air supply actuated by a diaphragm 21 subjected through conduits 22, 23 to the pressure in the outlet 12. To maintain equal pressures in the inlets to the pumps, valves 27, 28 in the respective inlets are connected to a common diaphragm 29 actuated by the pressure difference between the valve outlets. If the valve 27 sticks in the nearly closed position the diaphragm lifts a valve 127 against a spring 37 to open an orifice 27B while if it sticks in the nearly open position a valve 128 is lifted to open an orifice 28B. A simpler arrangement without the valves 127, 128 is described. The clearance between the rotors are sufficient to prevent air from being pumped to the engine if fuel is lost from one of the tank systems.