GB859479A - Aircraft fuel system - Google Patents

Abstract

859,479. Gas turbine plant. ROLLS-ROYCE Ltd. July 1, 1959 [April 25, 1958], No. 13294/58. Class 110 (3). An aircraft fuel system for controlling the supply of fuel to the combustion equipment of the engine comprising a variable capacity fuel pump and detector means for detecting icing-up of the fuel has means for locking the pump in a condition to prevent variation of the pump capacity, other than in response to variations in engine speed, when icing-up is detected. Fuel from a tank 15 is passed through a filter 16, booster pump 17, heater 18 and filter 19 to a variable output pump 20, the output of which is controlled as described in Specification 804,143. The pump discharges through a throttle valve 23 and shut-off cock 24 to the fuel manifold 14. The heater 18 is supplied with hot compressed air tapped from the compressor 11 through an electromagnetically-operated valve 25. The output of the pump 20 is controlled by the pressure in the chamber 29 communicated to the piston 28 through an orifice 30 and restriction 31. The orifice 30 can be closed at will by a half-ball valve 32 operated by a solenoid 34 energized by a switch 36. A pressure capsule 39 responsive to the pressure drop across the filter 19 lights the lamp 42 when a certain degree of icing-up of the filter occurs. The pilot then operates the switch 36 to close the valve 32 so as to fix the pump capacity and at the same time to supply heating air to the heat-exchanger 18. The switch 36 may be automatically opened after a predetermined time by a time delay device 37. The arrangement of the speed governor controlled half-ball valve 43 allows the governor to continue to operate when the valve 32 is closed.