GB899295A - Improvements in spill fuel systems for gas turbine engines - Google Patents

Abstract

899,295. Gas turbine plant. DOWTY FUEL SYSTEMS Ltd. May 13, 1959, No. 16469/59. Class 110 (3). [Also in Group XXIX] A main fuel pump 1 discharges into a pipe 8 leading to an engine driven circulating pump 2 which is part of a circuit comprising a supply pipe 4, spill nozzles 3, and spill pipe 6 that opens into the pipe 8 upstream of the pump; the pipe 8 may be connected to the supply pipe 4 instead of the spill pipe 6. The output of the pump 1 is controlled by a by-pass valve 11 actuated by a piston 18, the position of which is determined by a leak-off closure 45 on a hinged beam 27. The beam 27, which is urged counter-clockwise by a spring 29, is adjustable from a manual speed control lever 33, and is acted upon by a pair of opposed bellows 34, 35, the former being evacuated and the latter subjected to the output pressure of the compressor of the gas-turbine engine with which the fuel system is associated; the bellows are of equal area. Connected to the beam on the opposite side of its pivot 28 are a pair of opposed pressure pads 38, 39, each formed of a piston acting against a rubber diaphragm; each pad may alternatively comprise a bellows or diaphragm. Pad 38 which is larger than pad 39, is connected to the outlet of the circulating pump 2 whilst pad 39 is also connected to the latter but at a point radially between its inlet 7 and outlet 5; the influence of the pads on the beam 27 is speed responsive, the governing characteristic being stable since pressure in pipe 8 is added to that of the pump 2. When the engine is used at ground level only the bellows 34, 35 may be omitted.