Patent GB-774503-A (GB)
Title: Gas turbine starting system
Inventor: PERRY SYDNEY WILLIAM HENRY
IPC: F02C7/277
Filed: 1954-07-01
Abstract: 774,503. Gas-turbine plant. POWER JETS (RESEARCH & DEVELOPMENT), Ltd. June 30, 1955 [July 1, 1954], No. 19358/54. Class 110 (3). A gas-turbine plant which is started by supplying a gas stream to a row of radial flow turbine rotor blades mounted on the side face of a rotor of the plant has a row of radial flow turbine nozzle vanes mounted radially within the rotor blades on a face of the plant extending radially adjacent the face of the rotor and means for supplying the gas stream to the nozzle vanes so that it flows radially outwardly. The invention is described with reference to a gasturbine plant comprising an axial flow compressor C supplying combustion air to an annular combustion system S feeding an axial flow turbine T having a rotor 4 driving the compressor rotor 3 through a shaft 5. The turbine T also comprises a further rotor 6 which drives ducted fan blades 7 by the means described in Specification 774,502. The compressor rotor 3 is preferably as described in Specification 771,124 and is supported at its inlet end by a roller bearing supported from the stator casing by struts extending across the compressor inlet. The compressor stator is preferably as described in Specification 718,138. The outlet end of the compressor rotor is provided with a frusto-conical member 12 having an integral extension 12a which is supported by a bearing 22. The bearing 22 is supported in a frusto-conical member 20 attached to an inner ring member 18 supported from the compressor stator 17 by struts 19. The member 20 is also attached to a tube 21 forming a backbone of the plant. The driving shaft 5, which is connected to the extension 12a by a flexible coupling 13, carries at its rearward end a sleeve 24 to which is bolted the turbine rotor 4. The turbine rotor 6 is attached to an auxiliary drive shaft 25 supported from the backbone 21 by bearings 26, 27 and from the shaft 5 by a bearing 28. The adjacent faces of the turbine rotors 4, 6 are provided with co-operating rows 35, 36 of radial flow turbine blades, the row 35 being designed as nozzle blades and the row 36 as rotor blades. For starting the plant, these blades are supplied with compressed air supplied to a connection 37. This air passes into the space between the members 12, 20 and thence through holes 12b into the interior of the driving shaft 5. From the shaft 5 the air passes through holes 5a, 24b to the turbine blades 35, 36. Since the rotor is made up of a number of thin discs 3b which are liable to deflect under end loads, a thin dome-shaped member 40 is provided to take the load due to the compressed air. When the plant is running the connection 37 is closed. The turbine blades then suck air through the seals 39 and discharge it over the turbine rotor discs for cooling purposes. This air may be led under or in the rotor blades 4a, 6a before it is discharged into the gas stream. Combustion gases from a cartridge may be used for starting. The invention may be applied to a simple gasturbine engine in which case the blades 35 may be mounted on a stationary wall upstream or downstream of the rotor. The application to a compound turbine is also described. The radial flow turbine blades may be located on a compressor rotor.