Patent GB-878340-A (GB)
Title: Improvements in or relating to a fuel system for a gas turbine jet propulsion engine
Inventor: MILES ELLIS JOHN
IPC: F02K1/16
Filed: 1958-10-02
Abstract: 878,340. Dispensing measured quantities of liquids. BRISTOL SIDDELEY ENGINES Ltd. Sept. 30, 1959 [Oct. 2, 1958], No. 31446/58. Class 106(5) [Also in Group XXVI] A fuel system for a gas turbine jet propulsion engine in which fuel is supplied in separate paths to an afterburner and to a "hot streak" or starting injector arranged to ignite the afterburner includes an accumulator device having a chamber in which a charge of fuel to be supplied to the starting injector is stored under pressure and valve means, operable on the commencement of fuel flow in the separate burner path to place the chamber into communication With the injector to permit discharge of the fuel to the starting injector from the chamber after a predetermined time interval the hot streak fuel and the afterburner fuel being supplied from a common source, the afterburner fuel being controlled by a shut-off cock and the hot streak fuel being taken through a branch pipe positioned upstream of the shut-off cock. Fuel from a supply line 1 passes through two solenoid operated shut-off cocks 2, 3 in series to a flow control unit 4 which discharges, through a pressure maintaining valve 6, to the after burner 7. The flow control unit 4 is operated in response to an engine operating condition, such as the compressor delivery pressure at 8. A branch 9 is taken from the supply line 1 upstream of the cocks 2, 3 and leads to an accumulator 10. The accumulator comprises a chamber 12 housing a piston 13 biased to the right by a spring 14. The spaces on each side of the piston communicate with annular spaces around an axially movable plunger 15 in a chamber 16 urged to the left by a spring 17. When the plunger 15 is in the charge position shown, Fig. 2, the space on the left hand side of the piston is connected to a spill return pipe 21 to the pump through duct 19, annular passage 18, port 23, chamber 16 and duct 20. The space on the right hand side of the piston 13 is connected through duct 25, annular passage 24, annular space 26 and annular passage 27 with the connection 11 from the fuel supply line 9. When the shut-off cocks 2, 3 are opened, fuel flows through the control unit 4 to the burners 7 and also acts on the timing piston 40 and the' axially movable plunger 15 through a metering jet 37. A predetermined time after the putting into operation of the burners 7, the plunger 15 moves to the right and cuts off the connection between the inlet 11 and the chamber at the right hand side of the piston and at the same time connects the chamber to the pipe 33 leading to the starting injectors 34 located at each end of the turbine 35. The space at the left hand side of the piston 13 is connected to the supply line 30 via duct 19. The fuel pressure plus the force of the spring 14 forces the ignition fuel through the injectors 34. When fuel enters the space at the left hand side of the piston 13, a signal is transmitted through an outlet 47 to a pressure responsive control switch 45 which opens a variable and a nozzle 46. So long as fuel is supplied to the unit 4, the plunger 15 remains in its discharge position and no further fuel can enter the accumulator 10.