Patent GB-790645-A (GB)
Title: Improvements in or relating to a fuel control system for gas turbines
IPC: F02C6/20
Filed: 1955-05-04
Abstract: 790,645. Gas turbine plant. CHRYSLER CORPORATION. May 4, 1955 [May 10, 1954], No. 12924/55. Class 110 (3). [Also in Group XXIX] The supply of liquid fuel to the atomizer or burner of a gas turbine plant for an automobile, such as that described in Specification 768,845, is regulated by a control system comprising a combined air/fuel pump 206, Fig. 6, having air and fuel inlet pipes 408, 370 respectively, an air outlet pipe 402 connected to the burner and a fuel outlet pipe 368 connected to a manually-actuable throttle valve 250 connected to a spring-loaded piston valve 252 regulatable according to the speed of the turbine and communicating through a pipe 364 and a second spring- loaded piston valve 254, also regulable according to the speed of the turbine with a pipe 394 connected to the burner. The valve 252 controls the flow of fuel during the acceleration of the turbine up to its idling speed, while the valve 254 which is also connected directly to the throttle valve 250 through a pipe 362, controls the fuel flow during acceleration from the idling speed to the maximum speed of the turbine. The spring-loaded piston 274 of the throttle valve is actuated through an arm 292 mounted on a manually-operated shaft 294 and disposed in a space 290 formed by a flexible diaphragm 410 in a chamber having an opening 412 to atmosphere, said chamber, diaphragm and opening constituting a dashpot for damping oscillations in the pipe 360 and the spaces 342, 348. The pistons of the valves 252, 254 are actuated by flexible diaphragms 340, 346 attached to members 344, 350 secured to the pistons and exposed on their outer faces to fluid pressure generated by a rotor 152 normally driven through gearing from the turbine. The spring chambers of the valves are interconnected by the pipe 360 connected to a fuel tank 372 and in open communication with the interconnected spaces to the left of the diaphragms 340, 346, 410 and also through a solenoid-actuated diaphragm valve 256 with the fuel supply pipe 394 of the burner. With the turbine at rest and the ignition current off, the elements of the control system are in the positions shown in Fig. 6, the valve 256 being open and the spring chambers of the valves and the spaces to the left of the diaphragms flooded with fuel. To start the turbine, the operator turns on the ignition key thus energizing a motor which starts the turbine, the rotor 152 and a shaft 180, Fig. 4, carrying a cam 204 which, through a spring- loaded rocker arm 208, 218, effects oscillation of the air and fuel pumping diaphragms 230, 242 respectively of the air/fuel pump 206. The turning of the key also effects energization of the solenoid 382 and closure of the valve 256. Atomizing air is forced by the pump 206 through the pipe 402 to the burner, while fuel is pumped through the pipe 368 to the valve 250 thence passing through the ports 270 and the pipe 368 to the valve 252 whence it flows through the metering ports 308 and the ports 310 and pipe 364 to the valve 254. From the latter the fuel passes via ports 332 and the pipe 394 to the burner. As the turbine speed rises the pressure of the fluid on the diaphragm 340 increases thus forcing the piston 302 to the left and permitting an increased flow of fuel through the valve 252 'to the burner until the idling speed is approached whereupon the piston 302 moves still further to the left until it begins to cut down the flow through the ports 310. When the operator wishes to increase the speed of the turbine above the idling speed he turns the shaft 294 so that the arm 292 moves the piston 274 of the throttle valve to the left, thus allowing fuel to flow through the pipe 362 direct to the valve 254 and thence through the metering ports 330 to the ports 332. As the speed increases, the piston 326 of the valve 254 moves to the left until at a predetermined maximum speed it begins to cut down the flow through the ports 332.