Patent GB-757404-A (GB)
Title: Improvements in and relating to jet propulsion engines
IPC: F02K1/16
Filed: 1953-11-09
Abstract: 757,404. Jet propulsion plant. SOC. D'EXPLOITATION DES MATERIELS HISPANO SUIZA. Nov. 9, 1953 [Nov. 14, 1952], No. 30962/53. Class 110(3) [Also in Groups XXIX and XXXV] A jet propulsion engine in which fuel is supplied to a reheat chamber by a pump driven by an air or other gaseous fluid turbine has the air flow through the pump driving turbine controlled by a valve responsive to the pressure in the diffusing chamber at the entry of the engine and the fuel flow controlled by a valve responsive to the temperature on the upstream side of the reheat chamber. Fuel is supplied by a pump 4, Fig. 1 driven by a compressed air turbine, to the reheat burners 3. The air throttle valve 5 is controlled by a cap-- sule 6 responsive to the pressure in the diffusing chamber at the entry of the engine so as to open the valve when this pressure increases and vice versa. A needle valve 7 in the discharge of the fuel pump is actuated by a motor 12 controlled by an electrical comparing device 10 operated by a temperature detector 8 and a presetting device 11. When the .temperature at the in-- let of the jet pipe 1 is higher than that set on the device 11, the needle valve 7 reduces the fuel supply to the burners 3 and vice versa. A reduction of the fuel supply lowers the back pressure on the engine turbine and so reduces the temperature at the detector 8. If it is desired to reduce the fuel supply to the reheat burners considerably, a second valve 14, Fig. 2, operated by a manual control lever 15 is provided. Since a considerable reduction of the fuel supply will cause the motor 12 to try and increase the fuel supply and thus be uselessly energized, a switch 16 operated by the lever 15, when it is in its fully open position is provided to open the circuit of the motor 12 when the valve 14 is moved towards the closed position. A separate manually operated switch may be provided for this purpose. This switch may be operated when the control of the motor 12 is defective. In another arrangement the lever 15 is connected to the setting lever 13 of the presetting device 11 so as to reduce the preset temperature as the fuel. supply is reduced. In another modification, having a variable area propulsion nozzle, the area of the nozzle is controlled by the lever 15. In this case, no variation in the preset temperature is necessary. When the manually operated switch 16 is operated on account of defective control by the motor 12, the throttle 7 should be returned gradually to the open position. Fig. 5 shows an arrangement for doing this. The throttle valve 7 carries a piston 19 which is loaded on one side by a spring 20 and on the other by the pressure in a chamber 21. Fuel or oil under pressure is fed to the chamber 21 from a pipe 23" through a slide valve 22 and an orifice 29. The slide valve 22 is held in its right hand position as shown by the solenoid 30 arranged in series with the motor 12. The motor 12 is connected to a piston 28, with the slide valve in the position shown, the needle valve 7 is urged by the oil pressure towards its closed position until the ports 26 are opened so that each position of the piston 28 will correspond to a position of the needle valve 7. If the motor 12 is de-energized, the solenoid 30 will be deenergized and the spring 32 will urge the slide valve 22 to the left. The chamber 21 will then be cut off from the pipe 23 and connected to the drain pipe 24. Oil will drain gradually from the chamber 21 through the orifice 29 and the needle valve 7 will be moved towards its fully open position by the spring 20.