Patent GB-692072-A (GB)
Title: Method of regulating gas turbine plants
Filed: 1951-06-01
Abstract: 692,072. Gas turbine plant. MASCHINENFABRIK OERLIKON. June 1, 1951 [June 1, 1950], No. 13030/51. Class 110(iii) A gas turbine plant comprising a turbine driving a compressor only and a useful power turbine on a separate shaft, with at least one combustion chamber in front of each turbine which is controlled by regulating continuously the fuel supply of at least one combustion chamber and a valve by-passing the useful power turbine, has the bypass valve controlled by the power regulator of the useful power turbine and by a force dependent upon the speed of the compressor turbine set. The plant shown comprises a low pressure compressor 1, an intercooler 2, a high pressure compressor 3, an exhaust gas heat exchanger 4, a high pressure combustion chamber 5, a high pressure turbine 6 driving the compressor 3, and a generator 9, a re-heat combustion chamber 7 and a low pressure turbine 8 driving the compressor 1. A governor 12 driven by the turbine 6 controls the pressure in an oil system which controls a regulator 13 for a by-pass valve 14 and fuel supply regulator 19. The regulator 13 is also responsive to the oil pressure at the discharge of the pump 18 driven by the turbine 8. The arrangement is such that an increase in speed of the power turbine 6 closes the valve 14 whilst a decrease in speed of the compressor turbine 8 opens it. An increase in speed of the power turbine 6 also reduces the fuel supply to the combustion chamber 7. The fuel supply.to the combustion chamber 5 is controlled by a thermostat 21 operating a valve 23. An acceleration regulator 15 controls a blow-off valve 16 and a throttle valve 17. In a modification, the fuel supply to the combustion chamber 7 is additionally controlled by a thermostat in the gas supply conduit to the compressor turbine. A retardation device is placed between the thermostat and the fuel control valve so that it only acts when the new compressor speed has been reached. In this embodiment, the by-pass regulator is actuated by the pressure at the discharge of the high pressure compressor and the separate oil pump dispensed with. In another modification, the governor controls the fuel supply to the high .pressure combustion chamber which is additionally controlled by a thermostat acting through a retardation device. The fuel supply to the low pressure combustion chamber is controlled by a thermostat in the supply conduit to the compressor turbine. This thermostat is connected to the first mentioned thermostat so as to maintain a constant temperature difference with respect to it. These controls may be reversed so that the governor and first thermostat control the fuel supply to the low pressure combustion chamber and the second thermostat the fuel supply to the high pressure combustion chamber. In another arrangement both of the fuel supplies may be controlled by the governor and a thermostat. The low pressure turbine may be the useful power turbine and only one compressor may be used. The by-pass may branch off between the compressor and combustion chamber instead of after the combustion chamber as shown. The blow-off valve 16 and throttle valve 17 may be incorporated elsewhere in the plant. The pressure for actuating the regulator 13 may be taken from between the compressors or from a stage of a compressor. The fuel supply may be controlled by regulating the air pressure above the fuel in the fuel tank. Specification 602,554 is referred to.