GB655342A - Improvements in and relating to an internal combustion turbine - Google Patents

Abstract

655,342. Gas turbine plant. CURTISSWRIGHT CORPORATION. Aug. 15, 1947, No. 22701. Convention date, Aug. 31, 1946. [Class 110(iii)] [Also in Groups XIX, XXIX and XXXIII] A control system for a gas turbine having speed and power regulators and the load on, and the fuel supply to, which may be varied is provided with means to vary the fuel supply and/or the load in response to the speed regulator and the load and the fuel supply in-response to the power regulator. An accelerometer may be provided to maintain the turbine speed constant. Fig. 2 shows a system in which the pitch of the propeller-blades 58 and the fuel supply valve 32 are controlled by changes in the turbine speed and temperature and by the acceleration of the turbine, the changes in temperature being assumed to be synonymous with changes in power. The desired speed is set by a handle 116 which controls the spring loading of a speed governor having flyweights 104 carried by a gearwheel 106 driven by a wheel 108 mounted on a shaft 110 driven from the turbine shaft, while the temperature is set by a handle 122 which adjusts a rod 126 connected to one end of a link 128, the other end of which is connected to a rod 134 actuated by a turbine temperature measuring device 136 which includes a thermo-couple located in the turbine. The governor and temperature control rods 120, 140 are pivoted to a link 154 connected by links 158, 166 to links 162, 170 which regulate the positions of the control valve rods 90, 102 of the servo motors 74, 98 for adjusting the pitchchanging mechanism 84 and the fuel supply valve 32 respectively. The links 162, 170 are also adjusted by a rod 150 actuated by the servomotor 144 of an accelerometer 142 (see Group XIX). In a modification, the temperature control is replaced by a fuel/air ratio control, which affects both the fuel flow and the pitch-changing mechanism, and the speed control affects the latter only. Thus, the power or fuel/air ratio is set by a handle 122, Fig. 3, which controls a fuel regulating valve 180, the pressure drop across which is applied to a diaphragm 186 mounted on a rod 140a which carries a second diaphragm 198 subject to the pressure drop in an air flow measuring device mounted on the turbine,. and which through suitable linkage regulates the control valve' rods 90, 102 of the servomotors controlling the pitch-changing. mechanism 84 and the fuel flow valve 32 respectively. The speed governor regulates the rod 90 through linkage 212, 216, and the accelerometer 142 regulates both rods 90, 102 through the servomotor rod 150 and linkage 220, 234. In another arrangement, the pitch-changing mechanism is controlled by changes in the fuel/ air ratio, while the fuel supply is regulated both by speed changes and alterations in the fuel/air ratio. In a further arrangement, in which the fuel supply is controlled by changes in the fuel/air ratio and by acceleration, and in which the blade angle is controlled by variations in the fuel/air ratio and speed and by acceleration, the pitch-changing mechanism includes an electric motor, the current supply to which is controlled by a switch actuated by the rod 90. In another arrangement, the pitch-changing mechanism is controlled by changes in speed and by acceleration, while the fuel supply is controlled by the fuel/air ratio. Fig. 7 shows an arrangement in which the pitch-changing mechanism is controlled by the difference between the torque set by the pilots' control lever 122 and that developed by the turbine, while the fuel supply valve 32 is controlled by changes in speed. In this arrangement, the lever 122 loads one side of a diaphragm 278 through a spring 274, while the other side is subject to the fluid pressure in a torque meter on the turbine.