Improvements in fuel systems particularly for gas turbine engines

摘要

907,324. Supplying liquid fuel to burners. DOWTY FUEL SYSTEMS Ltd. April 7, 1960 [Jan. 7, 1959], No. 652/59. Class 75 (1). [Also in Groups XXVI and XXIX] In a liquid fuel supply system for the spill burner of a gas turbine engine a throttle valve is arranged for hydraulically balanced linear movement and the valve or a member associated therewith is rotated to reduce frictional resistance to movement. In Fig. 2 (not shown) a valve member 8 is slidably mounted in a sleeve 37 mounted for rotation in a bore 38 and rotated constantly by a gear 35 on a layshaft 34 driven by the engine. A further valve member 9 is slidably mounted in a rotary sleeve 39 driven by a gear 36 on the layshaft. Fig. 1 shows the valves 8, 9 but without the rotary sleeves. The valves control the spill flow of fuel from a burner 3 to the inlet of a pump 1. The valve 8 slides in a bore 7 and is controlled by a flyweight governor 12 loaded by a spring 13 loaded by a rack and pinion 14 actuated by a throttle lever 16. A land 21 on the valve 8 co-operates with a port 19 to control the flow of spill fuel from a pipe 4 to a passage 28. The valve 8 carries a damper piston 17 having passages for the flow of fuel from one side to the other. The other valve 9 comprises a tube slidable in the bore 7 and provided with a pair of tapered ports 25, 26 adapted to overlap with ports 23, 24. The tube is moved by a lever 29 controlled by an evacuated bellows 31 and an opposed bellows 32 in connection with compressor output pressure or a function of compressor output and air intake pressures. For steady running the land 21 throttles the flow of spill fuel to the port 19 and thence by passage 28 to the tapered port 26. The spill fuel flows through the tube valve 9 to a pipe 6 extending to the inlet of the pump. When the lever 16 is moved to increase the speed, the land 21 cuts off the flow of spill fuel to the port 19 but spill fuel continues to flow along a by-pass pipe 27 to the other tapered port 25. The valves 8, 9 are connected by a spring 11 which transmits to the valve 8 a force dependent on the pressure sensed by the bellows 31, 32. In another arrangement the fuel is controlled by a pair of throttle valves ineluding rotary drive to reduce friction, the valves being connected either in parallel or in series for independent adjustment by different signals. Specification 813,939 is referred to.