Improvements in or relating to regulating means for thermal gas turbine motive unitsused for driving electric direct current generators

摘要

605,785. Fluid-pressure servomotor-control systems. SOC. RATEAU. May 18, 1945, No. 12586. Convention date, July 10, 1941. [Class 135] [Also in Groups XXVI and XXXV] A gas turbine plant of the kind in which an auxiliary turbine or turbines drives a compressor or compressors supplying the combustion chamber or chambers, and including a power turbine or turbines mounted on an independent shaft or shafts driving one or more direct current generators, is controlled so that whatever the load on the generator the speed of the power turbine is brought back to that corresponding to the optimum efficiency for the load by adjusting either the excitation of the generator or, in the case when the excitation of the generator is automatically adjusted, the motive torque of the power turbine. In a gas turbine plant, Fig. 1, comprising a turbine Ta driving a compressor C supplying air to a combustion chamber Ch, the gases from which pass to the turbine Ta and the power turbine Tm driving a generator G1 on a separate shaft, the speed of the turbine Tm is controlled by varying the excitation of the generator G1. A speed responsive member R1 which may be a pump, controls the pressure above a spring- loaded piston p1 which is connected through a lever m4, cam m1, levers t, t1 and t2 to a servomotor S which operates a lever arm r3 of a rheostat R3 controlling the excitation of the generator G1. 'A governor R2 which is responsive to any factor which is a function of the load on the machine, in the case shown, the pressure at the inlet to the turbines also controls the movement of the lever arm r3 through the levers t, t1, t2 and servomotor S. The position of the pivot a on the lever t and the shape of the cam m1 are so chosen relative to one another that the power turbine operates at its point of maximum efficiency for the load. In a modification, the control mechanism can operate on the fuel supply to the combustion chamber Ch as well as the excitation of the generator G1. In a still further modification, the excitation of the generator is automatically controlled by a constant voltage regulator, the governors R1 and R2 are used to control the fuel supply to the combustion chamber Ch only. The governor R2 may be responsive to any factor which is a function of the load, e.g. the pressure or temperature ahead of either of the turbines, the quantity of air discharged by the compressor, the quantity of fuel supplied or the differential pressure between points situated before or after the turbines Tm, Ta. Specification 513,816, [Group XXVI], is referred to.