GB631068A - Improvements in thermal power plants - Google Patents

Abstract

631,068. Fluid-pressure servomotor-control systems. AKT.-GES. FUR TECHNISCHE STUDIEN. Oct. 9, 1947, No. 27153. Convention date, Nov. 1, 1946. [Class 135] [Also in Group XXVI] A gas-turbine plant in which a gaseous working medium describes a closed circuit including at least one turbine and at least one compressor and receives heat in a surface heat exchanger from a gaseous intermediate heat convector fluid which circulates in an auxiliary circuit containing a nuclear reaction pile, which plant is controlled by varying the density in the main circuit in proportion to the load, has means for maintaining the pressure of the heat convector fluid in the heat exchanger equal to the pressure of the working medium in the exchanger so that the mechanical stresses on the heat exchanger are minimised. In the gas-turbine plant shown the gaseous working medium flows through a closed circuit including a compressor 1, a heat exchanger 2, a surface heat exchanger 3 in which heat is supplied to the working medium from an external source, a turbine 4 which drives the compressor 1 and a generator 5 and a cooler 7<SP>1</SP>. The heat supplied to the surface heat exchanger 3 is obtained from a nuclear reaction pile 50 through which and the heat exchanger 3 a heat convector fluid is circulated by a blower 52. The power generated by the generator 5 is dependent upon the pressure level in the circuit which is controlled by the governor 8. A decrease in load on the generator 5 causes the governor weights to fly out and turn the lever 9 counterclockwise thus lowering the valve 11. This allows servo-fluid to pass into the space above the piston 13 which then moves downwards and through the collar 17 opens the valve 19. At the same time the lever 24 is moved in a counterclockwise direction which causes the collar 26 to open the valve 27 and the lever 49 to switch on the driving motor 45 of the charging compressor 44. Working medium is then extracted from the circuit at the point 38 and flows through pipe 37, valve 27, and pipe 41 into the suction 43 of the compressor 44 from which it is discharged through the pipe 46, valve 19 and pipe 34 into the storage vessel 35. The pressure at the point 66 then falls and the pressure beneath the piston 57 raises the valve 59 so that pressure fluid is supplied to the space 61 above the piston 60. The rod 70 then moves downwards and the stop 71 opens the valve 73. The rod 70 also moves the lever 88 in a clockwise direction which causes the stop 92 to open the valve 93 and the lever 99<SP>1</SP> to switch on the motor 81 of the subsidiary compressor 80. Heat convector fluid then flows out of the auxiliary circuit at the point 69 through the pipe 100, and valve 93, into the suction pipe 82 of the subsidiary compressor 80 which delivers it through the pipe 85, valve 73 and pipe 78<SP>1</SP> into the storage vessel 79. The reverse action takes place if the load on the generator is increased. By suitably dimensioning the cross-sectional area of the valves, it is possible to ensure that the amounts of working fluid and heat convector fluid supplied or withdrawn is such that the pressures on both sides of the tubes of the heat exchanger 3 are maintained substantially equal. The thickness of the tubes of the heat exchanger may be such that, when a sudden variation of the pressure in the main circuit occurs and the pressure in the auxiliary circuit does not follow at once, the tubes are stressed higher than the creep unit but below the yield point.