GB588083A - Fuel system - Google Patents

Abstract

588,083. Gas turbines. POWER JETS, Ltd., WALKER, D. N., FEILDEN, G. B. R., and MEESON, E. L. Oct. 30, 1941, No. 13976. [Class 110 (iii)] [Also in Groups XXVII and XXIX] In a gas turbine assembly for the jet propulsion of aircraft, the pressure of the fuel delivered to a throttle valve 4, Fig. 1, by a gear pump 1 is regulated in accordance with the ambient pressure by a relief valve 10. The throttle valve is byepassed by a second valve which closes when the throttle is opened. An over-speed-governor-controlled valve 5, which does not entirely shut, and a stop valve 6 are in series with the throttle valve. Fuel passes to the burners 9 through a dump valve as described in Specification 622,904. A low-pressure fuel pump 12 is driven by a starting motor 12c and its delivery is closed by a non-return valve 12D when the delivery pressure of the pump 1 rises sufficiently. In place of a second fuel pump 12, an accumulator may be provided which is charged by the fuel pump 1 before the stop valve 6 is opened. In the relief valve 10 the fuel enters at 3B, Fig. 2, raises and passes a valve 103 and leaves at 106. The valve 103 is loaded by a spring pack 104 abutting against a piston 105 behind which pressure oil is admitted through a control valve 109. This valve is operated by an exhausted box 112 in a chamber 113 to which the ambient pressure is admitted. A follow-up device is provided by a rod 117 and a lever 116 which moves the box 112 and valve 109 bodily. The stop valve 6 is a lift valve 307, Fig. 3, integral with a guiding piston and operated by an eccentric pin 305 on the spindle 304. The governor-controlled valve 5 is a piston valve operated by a speed governor. The piston rides in a sleeve having a series of ports and in the extreme high-speed position of the piston the last of the ports remains open. The gland of the valve stem is, preferably, a series of flexible diaphragms. The throttle valve 4 comprises a cone valve 503, Fig. 5, on a screwed stem 504 and a seating on a sleeve 502 which is adjustable axially by means of a screwed stem fixing. The valve 503 is byepassed by a channel 505A and ports 510c in a sleeve loaded by a spring 511. Before starting, the spring 511 keeps the ports 510c open and the flanged end 510B of the sleeve seated against a sealing ring. When the pump 12 is in running, the ported sleeve operates as a pressureregulating valve and when the pump 1 is delivering fuel at high pressure and the throttle is open, the ported sleeve is moved to close the ports 510c and to bring its flange up to a sealing ring 514. The spring-loading of the sleeve is raised by means of an abutment ring 513 screwed into the body and turnable by means of a squared spindle 512A.