GB677138A - Liquid fuel regulating means for use with prime movers - Google Patents

Abstract

677,138. Gas turbine plant. LUCAS, Ltd., J. Aug. 16, 1950 [Aug. 22, 1949], No. 21714/49. Class 110(iii) [Also in Group XXIX] A liquid fuel supply system for jet-propulsion engines, gas turbines and like prime movers comprises a restricted orifice g (or a venturi) in the fuel supply line from the pump f to the burners, a chamber divided into two compartments c, d by a diaphragm b (or a piston), a passage h between the upstream side of the orifice g and the compartment c having a restricted orifice i, an unrestricted passage k between a point in the line j at lower pressure and the compartment d, a valve n carried by the diaphragm b and cooperating with a seating m, a passage o leading from the seating through a further restricted orifice p to a discharge outlet, and fuel regulating means responsive to the pressure between the seating m and the orifice p. As shown the fuel supply is regulated by a variable delivery swash-plate pump f as described in Specification 577,016, (Group XXIX), the servomotor piston 5 being controlled by a leak-off valve 14 connected to a diaphragm 16 by a stirrup 15. The diaphragm 16 is loaded by a tension spring 18 adjusted by a lever 21 through rack and pinion mechanism 20 and is subject to the pressure difference on opposite sides of the orifice p. The passage k opens on the downstream side of the orifice g. In Fig. 2, the orifice g is replaced by a venturi g<SP>1</SP> and the passage k opens at the throat of the venturi. In addition the orifice p is variable by a throttle member 23 carried by a diaphragm 24 (or piston) subject to the pressures on opposite sides of the throttle member. The valve 14 controlling the pump servomotor 5 is actuated by two diaphragms 28, 29 connected by a stirrup 15. The upper diaphragm 28 is acted on by an evacuated elastic capsule 30 and also by the pressure difference on opposite sides of the throttle 23 whilst the lower diaphragm 29 is subject to the pressure downstream of the throttle and also to a further variable pressure depending upon a variable condition of the prime mover such as the pressure at a point in the fuel system or the blower air pressure. According to the Provisional Specification this variable pressure may be the atmospheric pressure.