GB631518A - Fuel supply and control systems - Google Patents

Abstract

631,518. Fluid-pressure servomotor-control systems. POWER JETS (RESEARCH & DEVELOPMENT), Ltd., FEILDEN, G. B. R., HOLL, R., and SIMONS, A. June 8, 1944, No. 11029. [Class 135] [Also in Group XXVI] In a spill-controlled fuel supply to a swirl burner of a gas turbine power plant, the spill is controlled manually and also in accordance with, at least, one variable factor. As shown, fuel is supplied by an engine-driven pump 1, Fig. 1, past a filter 3A, a manually-actuated stop-cock 6, and a " dump " valve 7, as described in Specification 622,904, to a ring 8 which supplies swirl chambers 9 leading to the burners. The fuel leaves the chambers 9 axially either to the burners or to a return ring 8A from which it flows past a non-return valve 13, through the throttled leaks 5, 10, to the line 11 leading back to the supply tank. Fuel enters the valve 10 at 203A, Fig. 2, and flows through the throttling valve 203 to the outlet 206. Valve 203 is controlled by atmospheric pressure which acts on evacuated capsules 212 connected to a servo-valve 209A. As the latter moves, it either connects the pressure fluid supply which is tapped off from the inlet at 221 with a chamber 205A containing a servo-piston 205 or it vents the chamber to exhaust. Movement of the servo-piston varies the loading of springs 204 on the valve 203. When the inlet pressure at 203A rises, fluid flows through a conduit 227 to the back of a piston 224 which moves a valve 220 to regulate the supply of pressure fluid to valve 209A. A follow-up movement is provided by a tappet rod 217 interposed between the servo-piston and a lever 216, the other end of the lever straddling a rod 215 to which the capsules 212 are connected. The pivotal point of the lever 216 is situated on a block 237 which can be adjusted up-and-down by means of a lever 232 to give a manual control. Actuation of the latter rotates a shaft 233 which has an eccentric connection 234 with the block 237. A relief valve 241 is provided in case the valve 220 should fail when no fuel is being used. The valve 5 comprises an engine-driven centrifugal governor controlling the leak past a piston throttle valve with staggered ports. " Dump " valve 7 drains fuel from the rings 8, 8A when the pump pressure is removed. Stop-cock 6 comprises a lift-valve actuated by an eccentric pin carried by the shaft to which the handle is affixed. A pressure relief valve 3C to maintain a regulated fuel supply pressure is also provided. In starting the system, the engine starter motor 12C drives an auxiliary pump 12 to supply pressure fuel past a non-return valve 12D. When an adequate fuel supply is being provided, motor 12C and pump 12 are stopped and the engine will be self-driving on the pump 1. The pump 12 can be replaced by an accumulator with a non-return valve. In an alternative arrangement for starting, a pump 19, Fig. 1B, is driven simultaneously and in parallel with pump 1 and feeds fuel past a non-return valve 20. When the fuel pressure exceeds a predetermined value, a change-over valve 16 opens and pump 19 circulates fuel idly through lines 16D, 16B. Specifications 595,834, [Group XXVI], and 600,654 are referred to. According to the Provisional Specification, the manual control may be applied by moving the cylindrical seat of the servo piston-valve and a similar manual control may be applied also to the centrifugal speed-governor.