GB1054680A - - Google Patents

Abstract

1,054,680. Gas turbine engines; turbine turning gear. BENDIX CORPORATION. Oct. 8, 1963 [Oct. 11, 1962], No. 39695/63. Headings F1G and F1K. A starting system for a turbine engine comprises a hot gas generator having a compressor driven by a first turbine and supplying compressed air to a combustion chamber, a second turbine for starting the turbine engine and connected to the latter through speed reducing means and an overrunning clutch, the two turbines being supplied with hot gases from the combustion chamber, and hydraulic means and control means arranged to rotate the compressor and to provide selfsustaining combustion. The compressor 13, Fig. 1, of the starting system supplies air to a combustion chamber 17, the combustion gases passing successively through a turbine 27 driving the compressor and integral therewith and through a turbine 31. The shaft 29 of the compressor is hollow, and the shaft 33 of the turbine 31 passes through it and is connected through reduction gearing 47 and an overrunning clutch 49 to a jetpropulsion engine (not shown) which is to be started. A hydraulic accumulator 119 is pressurized during a previous starting operation or manually by a pump 117 or by means of gas introduced through a valved inlet 122. When a manually-operated valve 127 is opened, fluid from the accumulator 119 passes through line 113 to drive a hydraulic pump-motor 41 as a motor for turning the compressor 13 through an overload disc clutch 39 and reduction gearing 37, the fluid returning through a line 101 and a valve 81 to a reservoir 107. A fuel pump 83 driven from the compressor shaft 29 delivers fuel through a line 67 and a check valve 63 to a nozzle 21, ignition being provided by a spark plug 23 energized through an ignition coil 135 by a generator 129 driven from the shaft 29. If the combustion chamber temperature, as sensed at 76, becomes excessive, a valve 62 shuts off the fuel supply. When the combustion chamber pressure reaches a predetermined value, a piston 73 opens a switch 79 to interrupt the ignition circuit and extinguish a signal light 134, whereupon the pilot closes the valve 127; and a piston 77 turns the valve 81 to the position shown in Fig.2 to enable the pumpmotor 41, now acting as a pump, to re-charge the accumulator 119 from the reservoir 107. The fuel pressure is now sufficient to open a valve 64 to allow additional fuel to be sprayed through a nozzle 19, and maximum power is then developed. The turbine 31 reaches a speed sufficient to start the jet-propulsion engine, and a centrifugal device 53 moves a valve 60 to the open position shown in Fig. 2 (whereupon hydraulic pressure holds the valve in this position), allowing pressure fluid to close a valve 61 to shut off the fuel supply and terminate the starting cycle (a further centrifugal device 55 would also open the valve 60 in the event of the shaft 29 overspeeding). The starting cycle can also be terminated at any time by closing a safety switch 95 to open the valve 60 by means of a solenoid 97. In a modification, the closing of valve 127 is done automatically by means of the piston 77.