Patent GB-856215-A (GB)
Title: Gas turbine engine control
IPC: F02C9/18
Filed: 1958-06-25
Abstract: 856,215. Gas-turbine plant. BENDIX CORPORATION, [formerly BENDIX AVIATION CORPORATION]. June 25, 1958 [July 12, 1957], No. 20432/58. Class 110 (3). [Also in Group XXIX] A control for a gas-turbine engine in which air is supplied to the combustion chamber through two paths one of which is equipped with a heat exchanger and the other a control valve, the turbine exhaust gases being dis-, charged into the atmosphere through two exhaust passages in parallel, one of which includes the heat exchanger and the other:a control valve, has means responsive to engine speed or an engine operating condition related to speed to control the control valves. A gasturbine engine, Fig. 2, comprises a compressor 12 supplying air to a combustion chamber 14 feeding a turbine 16 driving the compressor 12 and a useful power turbine 18. Air from the compressor 12 is supplied to the collector 26 from which it may flow through a path 30 and heat exchanger 34 to the combustion chamber 14 or through a path 32 controlled by a valve 36 direct to the combustion chamber. The exhaust from the turbine 18 may pass to the atmosphere either directly by a passage 38 controlled by a valve 42 or by a passage 40 which leads through the heat exchanger 34. The valves 36, 42 are operated together by a lever 44. Fuel is supplied to the nozzle 54 through a control 50, which is.regulated by a throttle lever 126. The control 50, Fig. 3, comprises a pump 82 which supplies fuel to a conduit 84 as a function of engine speed. Conduit 84 is connected to the.outlet conduit 52 by a spool valve 88. When the engine is cranked the spring 90 urges the valve 88 to the right and allows fuel to flow to the outlet conduit 52. Fuel under pressure is also supplied to chamber 98 but is allowed to escape through passage 108 to the pump inlet. As the speed of the engine builds up to the speed selected by the throttle lever 126, the force of the governor weights 112 overcomes the force of the spring 118 and causes the rod 116 to close off the passage.108. The pressure in chamber 98 then rises and piston 92 then moves to cause valve 88 to reduce the supply of fuel to the engine. Excessive temperature at the combustion chamber outlet will cause the valve V to be closed which also results in the valve 88 reducing the fuel supply. The valve 36 is connected by a rod 68 and bell-crank 70 to a push-rod 72 mounted on a piston 130 which reciprocates in a cylinder.132. Springs 148, 150 urge piston 130 to the right so as to move crank 70 and rod 68 to close valves 36, 42. The springs 148, 150 are opposed by the fluid pressure in chamber 136. A drilled rod 152 projects into chamber 136 and is. movable against the action of springs 156, 158 by centrifugal weights 154 rotated as a function of engine speed. During cranking and intermediate speeds, the high-pressure fluid delivered to chamber 136 is allowed to escape through the drilled rod 152 so the springs 148, 150 close the valves 36, 42. When the engine reaches a predetermined speed, the centrifugal weights 154 move the rod 152 into engagement with the piston 130 thereby cutting off the escape of the fuel from the chamber 136. The pressure in the chamber 136 rises and acting through the piston 130 causes the valves 36, 42 to be opened until there is sufficient clearance between the piston 130 and rod 152 for fluid to escape from the chamber 136. The by-pass valve area will therefore vary with engine speed. When the throttle lever 126 is placed in the idling position, the bifurcated lever 122 is moved to the left, causing rod 116 to seal the passage 108 which results in valve 88 cutting off the fuel flow. At the same time the lever 122 moves rod 162 to push-ball valve 164 off its seat allowing high pressure fuel to chamber 136. Piston 130 then moves to the left and opens the valves 36 and 42. In a modification, Fig. 4 (not shown), the leak-off from the chamber 136 is controlled by a halfball valve carried by a lever loaded in the opening direction by a spring and in the closing direction by one or the other of two diaphragms. One diaphragm is loaded by the pressure drop across the by-pass valve on the air side and the other by the pressure drop across the by-pass valve on the gas side.