Patent GB-718104-A (GB)
Title: Liquid fuel control means for jet-propulsion engines or gas turbines
Inventor: HARRIS THOMAS ALFRED
IPC: F02C9/16
Filed: 1951-07-31
Abstract: 718,104. Gas turbine plant. LUCAS (INDUSTRIES), Ltd., J. July 18, 1952 [July 31, 1951], No. 18077/51. Class 110(3) [Also in Group XXIX] Apparatus for controlling the supply of liquid fuel from a rotary pump to the burners of a jet propulsion or gas turbine engine comprises a liquid-actuated means for actuating a throttle between the pump and the burners and means for controlling the liquid acting on the throttle actuating means whereby only a reduced quantity of fuel can be supplied until a predetermined speed has been attained and thereafter the throttle is fully open. In Fig. 1, a centrifugal pump b supplies the burner c through a pipe a controlled by a throttle d. The throttle d is actuated by a spring- loaded piston g exposed on one side to the pump delivery pressure through a branch passage j. Closing movement of the throttle is limited by a stop k extending from a spring-loaded piston m. The stop is retracted when a predetermined fuel pressure is reached by fuel in a passage p acting on the piston m. Meanwhile the increasing fuel pressure acting through a passage x on a diaphragm s has opened a spring-loaded valve t controlling a pipe q leading to the spring-loaded side of the piston g so that the throttle is now kept open by the spring i. The governor 2 controls the flow in the pipe, g and comprises a shutter 4 movable transversely across a gap in the pipe q by a spring-loaded diaphragm 5 subject through a pipe 7 to the pressure in the fuel delivery pipe a or to any other source of liquid pressure related to the speed of the engine. The governor 2 and the lower side of the diaphragm are connected to the pump inlet by pipes 8, w. In Fig. 2, the stop k is dispensed with and the closing movement of the throttle is limited.by the liquid entrapped in a chamber 10 by the entry of the throttle d therein. The end 11 of the chamber is closed by a spring- loaded valve 12 supported by a diaphragm 13 connected on one side to the pipe q between the governor 2 and the control valve t and on the other side to the pump inlet. In this case the conical end of the throttle is replaced by a shaped part 9. In a further modification having a stop k as in Fig. 1, the two sides of the piston g are connected by a passage having a restricted orifice. In this case, the control valve t is normally kept open by a spring and is closed by fuel pressure acting on the diaphragm s. The shutter 4 is replaced by a leak-off valve controlling a passage branching off the pipe q and actuated through a lever by a diaphragm responsive to the fuel delivery pressure of the pump and therefore to engine speed. In a still further modification, the stop k is omitted and the throttle d is by-passed by a valve opened by a spring and closed by the fuel delivery pressure acting on a piston. In this case the piston g is more lightly loaded by its spring so that the throttle d closes immediately on starting and the by-pass valve closes subsequently on the attainment of a predetermined fuel pressure, the throttle having re-opened meanwhile under control of the control valve and the governor.