GB828829A - Fuel feed and power control system for gas turbine engines - Google Patents

Abstract

828,829. Gas turbine plant. BENDIX AVIATION CORPORATION. Oct. 3, 1956 [Nov. 1, 1955], No. 30172/56. Class 110 (3). [Also in Group XXIX] A gas turbine fuel supply control system comprises a second fuel conduit 17, 120, 124 removing fuel from downstream of a metering means 34 in a main fuel conduit 38, to a lowpressure source, the second conduit containing a restriction, e.g. valve 100, variable in response to engine speed at 108 and having the pressure drop across it controlled by a device responsive to metered fuel flow in the main conduit, e.g. valve 128, actuated by diaphragm 140 responsive to the flow at Venturi 118. To accelerate the engine a pilot-controlled lever 102 increases the loading of spring 104 and partly closes bypass valve 100 actuated by flyweight 108, whereby less fuel is by-passed to conduit 127 and more fuel passes at 17 to the burners. The increased speed acting through the centrifugal flyweight 58 and the crank 72 closes the hinged leak-off valve 82 whereby the pressure below the diaphragm 90 tends to close the pump by-pass valve 54 whereby the pressure between the pump 24 and metering valve 34 is increased to increase the flow of fuel and the speed of the engine. The increased engine speed produces an increased pressure in the bellows chamber 150 connected through restrictions 154, 158 to the pressure at the discharge and inlet of the compressor, respectively, whereby the hinged leak-off valve 180 reduces the pressure in chamber 186 beneath the piston 190 whereby the metering valve opens to further increase the fuel flow to the engine. For a given speed the pressure drop across the metering valve 34 is maintained constant by applying the pressure drop across a piston 78 controlling leak-off valve 82 and by-pass valve 54. The flow of fuel from the metering valve passes through a Venturi device 118 the pressure drop across which is applied to diaphragm 140 to actuate a valve 128 in the by-pass which also moves in response to the pressure drop across the by-pass valve 100 acting across the diaphragm 130 whereby the pressure drop across the by-pass valve equals the pressure across the Venturi. Specification 783,617 is referred to.