Patent GB-751361-A (GB)
Title: Improvements in or relating to liquid fuel control systems particularly for gas turbine apparatus
IPC: F02K1/16
Filed: 1954-01-06
Abstract: 751,361. Gas turbine plant. SHEPHERD, G. R. (Westinghouse Electric International Co.). Jan. 6, 1954, No. 385/54. Class 110(3) [Also in Group XXIX] A gas turbine fuel-supply system comprising a source of fuel under pressure connected to the inlet of a flow distributer having a number of outlets connected to a number of fuel nozzles and a control valve in the supply conduit to one of the nozzles to vary the fuel pressure therein has a pressure responsive valve responsive to the pressure in this supply conduit after the control valve to control the supply of fuel from the source to the flow distributing device. Fuel from a tank is supplied by a pump to a flow distributing device 25 which supplies fuel through a number of conduits 66 having balancing valves 26 to the fuel nozzles 27 and through a conduit 68 and control valve 75 to a master nozzle 27a. The nozzles are of the variable orifice type and comprise a piston valve 29 which is subject to the pressure of a spring 30 and of the fuel admitted to the bore 28. The flow distributing device 25 comprises a casing 33 in which is rotatably mounted a sleeve 40 having ports 41, 41a which cooperate with ports 37, 37a in a bushing 36. The sleeve 40 is controlled by a diaphragm 43 through a shaft 42 and linkage 46. Movement of the diaphragm in one direction is limited by an adjustable rod 48 and in the other direction by adjustable cam 47. The balancing valves 26 each comprise a slide valve 71 which controls the flow through a conduit 73 and is actuated by a diaphragm 64 responsive to the difference in pressure in the conduits 66, 68. A control valve 75 is arranged in the conduit 68 supplying the fuel nozzle 27a. The valve 75 comprises a casing 77 in the valve chamber 78 of which is mounted the valve element 83. The valve element consists of a tapered portion. with enlarged pistons 84, 85 formed thereon. The pistons 84, 85 are subject to the fuel pressure in the chambers 86, 88 which are controlled by a pair of needle valves 92, 93 attached to a lever 94 pivoted to the casing. The valves 92, 93 are controlled by solenoids 97, 98 which are energized by an electronic regulator. This regulator may also control a motor for varying the area of the propulsion nozzle when the gas turbine is used as a jet propulsion engine. The regulator may be responsive to engine speed and the temperature at the inlet to the turbine and may comprise means by which it may be set manually. A feed back potentiometer 101 is connected to valve element 83. Variations in the controlling variables will cause the valve 92 to open and the valve 93 to close or vice versa. This in turn will vary the leak off from the chambers 86, 88 and vary the pressure in the chambers and thus cause the valve element 83 to move and vary the flow area of the port 80 and the supply of fuel to the nozzle 27a. The resulting variation in back pressure in the conduit 68 will act on the diaphragms 64 and operate the slide valves 71 and also on the diaphragm 44 which will cause the flow area through the ports 37, 41 to be varied. The variations in the pressure in the fuel supplied to the nozzle 27a will act on the bypass valve 76 and thus vary the amount of fuel returned to the suction of the fuel pump by the conduit 96. The arrangement is such that with an increase of fuel supplied to the fuel nozzles the amount of fuel by-passed is decreased. A modification in which the valve 83 is controlled by a variable speed governor is described.