GB757504A - Means for controlling the supply of liquid fuel to engine or other combustion chambers - Google Patents

Abstract

757,504. Gas turbine plant; jet propulsion plant. LUCAS (INDUSTRIES), Ltd., J. July' 21, 1954 [July 25, 1953], No. 20869/53. Class 110(3) [Also in Group XXIX] In apparatus for controlling the supply of liquid fuel to the combustion chamber of a jet-propulsion engine or a gas turbine the blower air pressure acts on a pair of elastic bellows-like capsules f, i one of which (f) is responsive to variations of blower air pressure in the 'upper part of the pressure range and the other of which (i) is responsive to the pressure variations in the lower part of the range. The capsules which are evacuated are arranged coaxially in compartments b, c and connected by a stem j passing through a seal k. The outer end of the capsule i is anchored in the compartment c and the outer end of the capsule f is connected by a lever h to the control of a liquid-operated servo mechanism. The capsule f is pre-stressed by a yoke g which embraces it and so responds only to pressures above a predetermined value. Blower delivery pressure is admitted to the compartment b through a port e. The compartments b, c are connected through a further compartment d containing a third evacuated capsule m which is responsive to the higher blowerair pressures and at a predetermined pressure closes a normally-open valve n to cut off the compartment c from the compartment b. The lever h then responds to movement of the capsule f only, the compartment c then being vented to atmospheric through a restricted orifice o and the expansion of the capsule i then being limited by the wall between the compartments b, c. In a modification the capsules i, f are arranged with their axes parallel and are connected by a lever p, Fig. 3, with a sealed pivot q between the compartments b, c. This arrangement is shown in Fig. 3 applied to the control of a throttle, member x controlling an orifice y in the fuel supply line between a pump z and the burners. The lever h carries a leak-off valve s controlling a 'servo-piston v formed on or secured to the throttle x. The throttle opening is thus controlled according to blower delivery pressure. The pressure drop across the throttle x is applied to opposite 'sides of a spring-loaded diaphragm 6 which operates through a lever 8 a servo-vent valve 9 controlling a spring- loaded servo-piston 12 adapted to control the output of the pump z.