GB614202A - Improvements in mechanism for controlling the supply of fuel to internal combustion turbines - Google Patents

Abstract

614,202. Fluid-pressure servomotor systems. S.U. CARBURETTER CO., Ltd., KENT, R. L., and DAVIES, K. R. July 6, 1946, No. 20223. [Class 135] [Also in Group XXVI] A gas turbine liquid fuel control system comprises a metering orifice regulated by means responsive to variations of turbine speed and controlled by cam mechanism providing desired relationship between fuel flow and turbine speed during acceleration and deceleration and a manually - controlled cam for selecting the turbine speed. Fuel from a turbine-driven, speedcontrol pump enters through a pipe 5 and flows past a disc flow-meter 7 connected to a tube 8 having a slot 28, the edges of which rotate a plate 13 to control a metering orifice 10 in the wall 4 leading to a conduit 11 and discharge conduit 12 leading to an injection pump feeding the burners. Variations in fuel flow rotate the spring-loaded disc 7 and move it axially so that the plate 13 carried by a rod 16 attached to a barometric capsule 20 is rotated by the member 8 to vary the orifice 10. The movement of the member 8 is controlled by cam-followers 34, 35 co-operating with a manually-operated cam 32 and a stationary cam 31. For accelerating from the idling position shown in Fig. 3, the cam 32 is rotated by lever 33 to set the desired speed and the cam-follower 34 moves along the face 45 of cam 31 under the action of the increasing fuel flow on disc 7 until a balanced position is reached, Fig. 4, 'when the follower 35 engages the cam 32. Similarly, the fuel supply during deceleration is controlled by the movement under the action of the cam 32 of the follower 34 along the face of cam 31. A diaphragm 50 controlled by the fuel pressure on opposite sides of the orifice 10 actuates a servomotor valve 53 which controls the injection pump output to maintain a constant pressure drop across the orifice 10, which pressure drop may also be controlled by temperature-responsive means. The plate 13 is pressed against the wall 4 by a spring 15 and is held against the lower edge of slot 28 by a torsional spring 29 acting on the rod 16. For a turbine with assemblies of rotors turning at different speeds, two or more speed-control pumps driven by the respective rotors may be arranged to feed the flow-meter 7 and provide a fuel now in accordance with any desired combination of these speeds.