GB837309A - Improvements in or relating to gas-turbine engines - Google Patents

Abstract

837,309. Gas-turbine plant. ROLLSROYCE Ltd. Oct. 28, 1957 [Nov. 8, 1956], No. 34217/66. Class 110 (3). [Also in Groups XXIV and XXIX] A gas-turbine engine comprising a turbine and a coaxial driven member interconnected by a driving shaft has a tube or the equivalent located within and connected at spaced locations to the shaft, one location being in the region of the load and another location being in the region of the turbine rotor, the tube or equivalent being fed with a fluid under pressure so as to provide a pressurized chamber which is connected to pressure responsive means controlling the fuel supply, the arrangement being such that when the driving shaft fractures, the tube or equivalent also fractures resulting in reduction of pressure on the pressure-responsive means and so reducing the engine fuel supply. An axial flow compressor 10a, 10b supplies combustion air to combustion equipment 11 feeding a turbine 13b driving the compressor through a hollow driving shaft 14. Fuel is supplied to the injector nozzles 12 by a swashplate pump 15 the delivery of which is controlled by a unit 16. The angle of the swashplate is controlled by a piston 21 the position of which determined by the amount of leak-off from the chamber 23. The control unit 16 comprises a flexible diaphragm 29 carrying a lever 30 loaded by an evacuated capsule 35 responsive to changes in atmospheric pressure, and a piston 33 acted upon by the pump delivery pressure and a spring 31. The lever 30 carries a valve element 28 which opens or closes the end of the vent pipe 27 so that an increase of atmospheric pressure or a decrease of pump delivery pressure will cause an increase in the fuel delivery from the pump and vice versa. A lubricating oil pump 37 delivers oil through a pipe 38 and muff 39 to a tube 40 supplying oil to the engine bearings. The tube 40 is connected to the rotor system by splines 41, 42. A constriction 45 in the tube 40 forms a chamber 46 having a restricted oil inlet. The wall of the chamber 46 is provided with a shear neck in the form of a helical groove 47. The chamber 46 is connected by ducting 48 to a chamber 53 having one wall formed by a flexible diaphragm 51. The diaphragm 51 carries a leak-off valve 59 which is urged to the open position by a spring 56 and to the closed position by the pressure in the chamber 53. In the event of failure of the driving shaft 14, the tube 40 will be quickly fractured in the region of the shear neck 47. The pressure in the chambers 46 and 53 falls and the spring 56 opens the valve 59 which causes the delivery of the pump 15 to be reduced rapidly. A deaerator 49 separates air from the lubricating oil. A flanged plug 65 which is rotatable relative to the tube 40 and the turbine casing forms a connection between the ducting 48 and tube 40. The invention can be applied to a gas-turbine plant driving a propeller or to a compound gas-turbine engine.