Patent GB-668516-A (GB)
Title: Improvements relating to the regulation of gas turbine plants
Filed: 1950-06-07
Abstract: 668,516. Combustion turbines; axial flow compressors. SULZER FRERES SOC. ANON. June 7, 1950. [June 8, 1949] No. 14190/50. Classes 110(i) and 110(iii). [Also in Group XXIX] A method of regulating working fluid pressures in a gas turbine plant having two mechanically independent compressors 33; 1, 4 in series, comprises regulating the delivery pressure of one compressor in dependence upon the delivery pressure of one or other of the compressors, and regulating the delivery pressure of the other compressor in dependence upon the ratio between the delivery pressures of the two compressors. The regulating means include pressure-sensitive elements 47, 48, 49, subject to delivery pressures, which affect the positions of pistons 50, 51, 52 controlling the flow of oil to servo-motor pistons 54, 57, 58 which act through link systems to control byepass valves 41, 36. The latter regulate the outputs of turbines 15, 28 in accordance with the setting of a hand-control lever 46. Fig. 1 shows one plant in which a turbine 15 drives L.P. and H.P. compressors 1, 4, having an inter-cooler 3, a turbine 24 drives a charging compressor 33 and a turbine 28 gives power externally. Delivery into outlet 5 is divided, one part passing through a heat-exchanger 6 being then divided into two streams 9, 12 the former being further heated in an exchanger 10 and then driving the turbine 15. This stream is exhaustedthrough 16 into the exchanger 6 tube system, and reenters the L.P. compressor by way of pipe 18, cooler 19 and inlet 2. The compressed air in 12 supplies. a combustion chamber 13 of a heater 11. The air in pipe 7, after being heated in an exchanger 8, also passes to the chamber 13, through a pipe 20. A mixture of combustion gases and hot air flows through the tubes 10 to supply the turbine 24 and passes to a combustion reheater 26 for use as working-fluid in the turbine 28. The exhaust gases act as heating fluid in the exchanger 8. The compressor 33 replaces, from the atmosphere, air lost from the system. A servo-motor 37 is actuated, to open or close the valve 36, through an impulse pipe 38 leading from a regulating device II, Fig. 2, in a box 39. Turbine 15 is similarly controlled by a byepass valve 41 and an impulse pipe 43 leading from a regulating device I in the box 39. The regulating devices are influenced by the delivery pressure in pipe 5, acting through a pipe 44, on the device 47, and also by the pressure of the chaxging compressor 33 acting through a pipe 45 on the device 48. Pipe 44 also acts on the pressure-sensitive device 49. The required valve for plant output is selected manually by a lever 46 acting on cams 65, 66 to adjust springs 69, 70 and thus regulate the flow of servo-fluid to and from lines 75, 76. Opening the valve 36 causes a drop in pressure of the working fluid, which has passed through the turbine 24, increases the pressure drop across the turbine which gives off more power and drives the compressor 33 faster to increase the pressure level of the whole plant. Similarly, opening the valve 41, under impulse through the pipe 43, increases the output of the turbine 15 and the pressure of the air delivered through pipe 5. The positions of pistons 54, 57, 58 raises or lowers the ends of links 81, 60, the latter being pivoted at 59 which pivot is adjusted through a bell-crank lever 108 under influence of a servo-motor 101. Cylinders 80, 92 are adjusted under influence of servo-pistons 78, 90 and their pistons 79, 91 by rods connected to links 81, 93. Fluid in the cylinders 80, 92, when moved, passes round the pistons through throttle valves 84, 97. Cams 65, 66, when moved to the right, depress one rod 67 and allow elevation of the other 68. Servo-motors 77, 89, control the loadings of springs 85, 98 and thus the positions of valves 86, 99 and pressures in pipes 43, 38. In Fig. 3 air from the atmosphere passes through L.P. and H.P. turbines 111, 114, with intercooler 113, is heated in the space surrounding tubes 116 of an exchanger 117, flows through a pipe 118, combustion chamber 119 to supply turbines 123 and 126. The turbine exhausts are led through a pipe 127 into a turbine 128, driving the L.P. compressor 111, the turbine exhausting through the tubes 116 of the heat-exchanger 117. The quantity of fluid passing through the turbine 126 is regulated by a valve 130 under impulse in a pipe 136 controlled by a servo-motor 137. Similarly the quantity of fluid flowing through a byepass 132, into turbine 128, is controlled by an impulse through a pipe 135. The latter control is influenced by the pressures in pipes 122, 139, acting on pressure-sensitive devices 49, 48 respectively. A hand-control lever 46 adjusts the positions of springs 69, 70 and thus the positions of servo-valves 71, 72. The pressure in the pipe 122 also acts on the pressuresensitive device 47. The regulating devices can have other suitable mechanical, hydraulic, pneumatic or electrical actuating elements.