Patent GB-676417-A (GB)
Title: Improvements in apparatus for regulating jet propulsion engines and propeller turbine engines
IPC: F02K3/00
Filed: 1948-07-27
Abstract: 676,417. Gas turbine plant. OESTRICH, H. July 27, 1948 [Aug. 4, 1947], No. 20060/48. Class 110(iii) [Also in Group XXIX] A fuel system for a gas turbine engine comprises a variable area metering device, separate elements responsive to variations of air temperature and pressure at the compressor inlet and means for transmitting the movements of these elements to the variable area metering device so that the area of the fuel passage varies in proportion to the product of the air pressure with a function of the air temperature, which function increases as the air temperature decreases. Hand controlled means for varying the flow through the metering device are also provided. Fuel is fed by a pump 5 through a conduit 6<SP>1</SP> to a valve 7 which connects the conduit 6<SP>1</SP> either to the conduit 6<SP>2</SP> having at its inlet a metering orifice 8 or to the conduit 18 which byepasses the orifice, The fuel flows through the conduit 18 under idling conditions and the amount is controlled by a valve 19. A spring-loaded valve 14 maintains the pressure drop across the valve 7 and metering orifice 8 constant so that for any given position of the valve 7, the fuel flow to the metering device 17 is constant. The metering device 17 consists of a spring-loaded piston 21 which divides the flow through the conduit 6<SP>2</SP> into two parts one of which flows through the conduit 65 to the burners 22 and the other of which flows through the conduits 16<SP>1</SP> and compensating valve 23 to the fuel return line 16. The function of the compensating valve 23 is to maintain the pressure on the opposite sides of the piston 21 equal so that the flows through the conduits 65 and 16<SP>1</SP> are dependent solely on the position of the piston 21. The fuel passing through the conduit 65 to the burners 22 is divided, part passes through an unobstructed conduit 6<SP>4</SP> and part passes through a spring-loaded valve 50 and conduit 6<SP>3</SP>. The conduit 6<SP>4</SP> allows a minimum pressure in the conduit 65. The metering device 17 is actuated by a servo-motor 56 controlled by a slide valve 26 which is, in turn, actuated by a rod 38<SP>2</SP> connected to capsules 53, 54 mounted in a chamber 52. The chamber 52 is connected through a conduit 29 to an intake 24 mounted in the intake of the compressor 1. A second rod 38<SP>1</SP> also connected to the capsules 53, 54 is spring-loaded and is provided at one end with a bearing point for a lever 36. The lever 36 also pivots on a pin 35 which is slidable in a slot 36<SP>1</SP>. The pin 35 is carried by a capsule 34 which expands or contracts due to variations of temperature of air from the intake of the compressor passing through the chamber 66. A spring-loaded valve 43 controlled by a centrifugal governor 42 is inserted in the conduit 31 connecting the slide valve 26 with the servo-motor 56. The arrangement is such that when the engine overspeeds, servo-fluid passes into the cylinder 27 and decreases the amount of fuel fed to the burners 22. When the invention is applied to a gas turbine engine having a variable area jet propulsion nozzle or driving a variable pitch propeller, the valve 43 is omitted and the governor 42 connected to the control of the jet nozzle or variable pitch propeller. Specifications 603,884, 604,466, 605,991, 612.840, 620,052, 625,824. [Group XL(c)]. 625,829 and 652,854, [both in Group XXVII], are referred to.