GB694422A - Improvements relating to fuel systems of gas-turbine engines - Google Patents

Abstract

694,422. Automatic temperature control. ROLLS-ROYCE, Ltd. Feb. 13, 1950 [Feb. 21, 1949], No. 4740/49. Class 38 (iv). [Also in Groups XI, XII, XXVI and XXIX] Fig. 6 shows a fuel supply system for auxiliary combustion equipment for augmenting thrust by burning fuel in the jet pipe 14 of a gasturbine engine, associated with meansfor increasing the effective area of the jet nozzle when fuel is so burnt. A thermocouple 36 controls the retraction of the segments 15a, and the supply of fuel to main injectors 40 is made dependent upon the sensing of a fall in temperature in the jet pipe 14 caused by the opening of the nozzle 15. A resistance thermometer 61, located in the jet pipe 14 upstream of the main injectors 40, is connected to form one arm of a bridge circuit 62. The latter is balanced and thus has no output when the temperature of the exhaust gases sensed by the resistance thermometer 61 has a selected value. On a change in temperature of the resistance thermometer 61, the bridge 62 becomes unbalanced and the resulting output passes to a pair of relays 64, 64, 65 so arranged that on a fall of temperature in the jet pipe 14 the relay 64 is energized, and on a rise the relay 65 is energized. The relay 64 completes a circuit 66a to drive a reversible electric motor 60 in a direction to open a throttle 135 in the pipe 26 supplying fuel to the main injectors. When the relay 65 is energized a circuit 66b is completed to rotate the motor 60 in a direction for closing the throttle 135. A preselected temperature may thus be maintained in the jet pipe upstream of the main injectors 40. Specification 641,910 is referred to.