GB533882A - Improvements in and relating to elastic fluid power plants - Google Patents

Abstract

533,882. Controlling steam generation. BRITISH THOMSON - HOUSTON CO., Ltd. Dec. 8, 1939, No. 31827. Convention date, Dec. 8, 1938. [Class 51 (i)] [Also in Group XXVI] Boiler feed, fuel and air pumps 18, 21, 22 are driven by an auxiliary turbine 12 in front of the main turbine 13. The inlet valves 23 of the turbine 12 are controlled only by a pressureresponsive device 30 so as to maintain the pressure before the valves constant. The inlet valve 34 of the main turbine 13 is controlled by a device 37 manually or automatically adjusted in accordance with the speed or load of the turbine 13 and by a device 38 responsive to over-speed of the turbine 12. A byepass valve 41 is opened when the valve 34 shuts. If the load on turbine 13 increases, the valve 34 is opened wider. This causes an immediate reduction in the back pressure of turbine 12 and a consequent increase in the speed of that turbine and the pumps. The subsequent rise in the pressure at 31 brings about a further opening of the valves 23. The byepass valve 41 may be separately operated by a rise in the pressure in the pipe 40 in front of it. The devices 37, 38 may act upon separate valves in series. Regulation is also effected by the water-level device 60 in the steam generator 10, in conjuction with a throttle 65 in the air supply and flow responsive devices 67, 68 in the fuel and air lines which control a fuel valve 87. If the waterlevel falls, the supply of both air and fuel is immediately decreased and, due to a fall in the steam pressure of the generator, the valves 23 will be closed slightly. Since the load on the turbine 13 is unchanged, its speed will fall and the valve 34 be opened further. The turbine 12 will then speed up owing to the reduced backpressure and the boiler feed will be correspondingly increased. A pressure relief byeppass 90 is provided for the fuel pump.