GB719469A - Improvements in or relating to fuel systems for internal combustion engines - Google Patents

Abstract

719,469. Gas turbine plant; centrifugal pumps; centrifugal governors. ROLLS-ROYCE, Ltd. Sept. 11, 1952 [Sept. 11, 1951], No. 21432/51. Classes 57, 110(1) and 110(3) A fuel system for a gas turbine plant comprises a centrifugal fuel pump having flow-restricting means connected with its delivery and flow-metering means in its inlet, the flow-metering means being controlled by a speed governor sensitive to a rotational speed to be governed, the arrangement being such that in operation of the pump the radial depth of fuel in the pump impeller is less than the impeller radius. The fuel tank 14, Fig. 1. is pressurized by connecting it through a pipe 44 to an intermediate stage of the compressor 10 of the gas turbine plant or through a pipe 45 to the delivery of the compressor. Fuel passes to the eye of the fuel pump impeller 20, Fig. 5, by way of a duct 15 and a valve 39. A centrifugal governor 29 driven, together with the impeller 20, from the rotor 10 a of the compressor 10, tends to close the valve 39 against the combined effect of a spring 42 and the pressure exerted on a flexible diaphragm 50. The diaphragm 50 is subjected on one side to the pressure within a chamber 51. This pressure is a fixed proportion of the compressor delivery pressure and may be obtained by connecting the chamber 51 by way of a duct 52 to the pipe 44 or 45. The cavity 21 is vented to atmosphere through pipes 54, 43. In a modification, Figs. 2 and 4, the diaphragm 50 is omitted, and the stem 37 of the valve 39 is made hollow to provide a passage connecting the cavity 21 to the vent pipe 43. The centrifugal governor 29 comprises bob weights 30 secured to the ends of a spring steel strip 34 overlying the end of the stem 37 and to the ends of spring steel strips 31 carried by lugs 32 projecting from a boss 33 secured to the impeller 20. The bob weights 30 have inwardly extending arms 35 ending in knife edges 36 which bear upon the centre of the strip 34 to load the valve 39. The centrifugal governor 29 may be replaced by a hydraulic governor comprising a fixed capacity pump driven at the speed to be governed and delivering liquid through an orifice which may be adjustable, the pressure drop across the orifice being applied to a piston which moves the valve 39 against a resilient load which may be adjustable. Specification 709,002 is referred to.