GB738966A - Improvements in combined fuel injectors and igniter plugs particularly for gas turbine engines - Google Patents

Abstract

738,966. Sparking plugs. GENERAL MOTORS CORPORATION. Dec. 28, 1953 [Dec. 29, 1952], No. 35967/53. Class 7(4). [Also in Group XI] A combined fuel injector and igniter device particularly for the combustion system of a gas turbine engine comprises a substantially cylindrical duct adapted to project into the combustion system, a supply pipe to feed fuel to an annular chamber lying around the circumference of the duct, and containing a filter element, a hollow central electrode forming a fuel conduit and comprising an annular chamber containing a second filter element, and passages to conduct fuel from the first filter to and through the second filter to be discharged through the electrode conduit. In the device illustrated the electrode is supported by a member 92, Fig. 1, which is disposed in an insulating sleeve 36 having an outer shoulder resting on a spring washer 32 supported by an inner shoulder of an outer shell 2. A tubular insulator rests on the flared upper end 94 of the member 92 and receives an electric supply cable (not shown) retained by a cap (not shown) threaded on to a surrounding tubular shield 170. Liquid fuel is supplied through an elbow connector 58 maintained by a spring clip 68 so that a resilient outlets nipple 56 thereof is pressed through the wall of the shell 2, and the fuel passes into an annular chamber 210 containing a stainless steel mesh filter 44, and thence through annular spaces 214, 216, four holes 218 in the head 94, and a further fine mesh filter 150 wound around a core 144. The fuel discharges through a bore 226 in the core 144 into a valve chamber 228 to force a valve member 136, Fig. 2, from its seat against the action of a spring 134. The fuel then flows along the flat sides of the member 136 and past the bottom 234 and bores 236, 238, and 240 in a core 132 to pass into chambers 244, 246 from which it discharges through nozzles 128, 130. The discharged fuel impinges on inclined faces of target pins 110, 112 to produce a finely atomized spray which is mixed with air in a venturi 22 and ignited by sparks passing radially extending electrode prongs 196 and the lower end 26 of the venturi. The prongs 196 extend from a stub 118 held by a pin 202 in a holder 108 press fitted into the lower end of the member 92. The venturi end 26 is formed of a metal which stores sufficient heat to retain the flame thereat. When assembled in a gas turbine engine the lower part of the shell 2 extends into a well 12 disposed between the outer casing wall 10 and the flame tube wall 14, and part of the air flowing between the walls 10, 14 passes through apertures 204 in the wall of the well 12, and a part flows through circumferential ports 206 in the shell 2 and the remainder flows through the venturi 22 via ports 208.