GB799934A - Apparatus for controlling the fuel supply to gas turbine engines - Google Patents

Abstract

799,934. Gas turbine plant. HOBSON, Ltd. H. M., and McCOURTY, W. D. April 30, 1956 [April 29, 1955], No. 12529/55. Class 110 (3). [Also in Group XXIX] Apparatus controlling fuel supply to a gas turbine engine during acceleration to a controlled speed comprises an engine driven fuel pump supplying the engine through two series orifices 2, 3, a valve 5 controlling orifice 2 to prevent excessive overfuelling during an initial critical engine speed range, a speed-governor controlled metering valve 8 controlling orifice 3 to regulate the fuel when the engine speed exceeds the critical range and to maintain the controlled speed, a splitter valve 15, 16 downstream of orifice 3 dividing the fuel between a line 19 leading to the engine and spill line 18, 13, and a device 28 subject to ram pressure for actuating valve 14 to increase engine fuel flow and decrease spill in response to increase in ram pressure. Valve 5 is actuated by piston 6 loaded on one side by spring 7 and spill pressure and exposed on the other side to centrifugal pump pressure. Valve 8 is actuated by fuel flowing through piston orifice 10 and controlled by a valve 12 actuated by a speed governor. Valve 14 is actuated by fuel flowing through piston orifice 24 and controlled by valve 26 actuated by a bellows 28 responsive to ram pressure. To ensure the percentage split of the flow is always a function of ram pressure irrespective of the controlled speed, the pressures downstream of the valves 15, 16 are made equal by a spill line valve 30 actuated by a diaphragm 31 responsive on either side to the respective pressures. In a modification valve 26 is hinged and actuated by a capsule, piston 23 is exposed to full pump pressure, valve 30 is a balanced double beat valve and its actuating diaphragm may have one side exposed to fuel pressure downstream of valve 15 or to combustion chamber pressure. Specification 712,646 is referred to.