Patent GB-755925-A (GB)
Title: Improvements in gas turbine plants
IPC: F02C7/36
Filed: 1952-03-11
Abstract: 755,925. Centrifugal and axial flow compressors; gas turbine plant. TURBEX CORPORATION. March 11, 1952 [April 18, 1951], No. 6314/52. Classes 110(1) and 110(3) A gas turbine plant in which a turbine drives the compressor and a power output shaft through a differential gear, the compressed air from the compressor being supplied to a combustion chamber feeding the turbine has automatic fuel control means for varying the fuel flow to the combustion chamber so as to maintain the compressor speed constant independent of the turbine and output shaft speeds. The compressor shaft 30, Fig. 1, carries a large internal gear 33 which meshes with planet gears 39 mounted on a rotary member 37 connected to the turbine shaft extension 34. The planet gears 39 also mesh with a small sun gear 42 carried by a high speed output shaft 41. The shaft 41 drives the output shaft 31 through gearing 44, 46 and 48. The rotary member 37 has pockets 37<SP>1</SP>, Fig. 2, which house cylindrical rollers 40. The rollers 40, when the speed of the turbine shaft 34 starts to exceed the speed of the compressor shaft 30, lock the two shafts together. The compressor drives through gearing a fuel pump and governor 103 arranged to control the fuel flow to the combustion chamber 54 so that the compressor speed is maintained substantially constant at the value set by the lever 104. The compressor shaft is also connected through gearing to a starter motor 100. A brake drum 115 is mounted on the output shaft 31. When the engine is to be started, the shaft 31 is braked by means of the brake shoes 116. The control lever 104 is then set for the idling speed and the starter motor 100 energized to drive the compressor. Under these conditions, the compressor rotates faster than the turbine and the clutch 37, 40, 33 remains disengaged. When idling speed is reached the valve 109 is opened and combustion started, the turbine then drives the compressor at idling speed. The brake is then released and if the torque on the shaft 31 is insufficient for the load, the control lever 104 is moved to increase the compressor speed. If the turbine speed starts to exceed the compressor speed the clutch 37, 40, 33 will engage and lock the turbine, compressor and output shafts together. Under these conditions governor 103 will control the speed of all three shafts. If the torque on the shaft 31 is increased to such an extent that the turbine speed is reduced below that of the compressor the clutch 37, 40, 33 will disengage. If a driving torque is applied to the shaft 31 the clutch will engage and the engine will act as a brake and the - governor 103 will reduce the fuel supply to the combustion chamber to maintain the compressor at its set speed. In a modification, comprising a centrifugal compressor, the turbine and compressor shafts are arranged at right angles to one another and the output shaft is 'arranged in line with the compressor shaft. In this arrangement, a heat exchanger heated by the turbine exhaust gases is arranged to heat the air entering the combustion chamber. In another modification, the differential gear is arranged between the compressor and turbine and the output shafts are located inside the turbine and compressor shafts. In a further modification, the output shaft is at right angles to the aligned compressor and turbine shafts- and the differential gear is arranged between the turbine and compressor. The clutch may be arranged between the output shaft and the compressor or turbine shaft. Specifications 595,357 and 756,015 are referred to.