Patent GB-499756-A (GB)
Title: Improvements in or relating to steam power installations employing tubular steam generators with small liquid content
IPC: F01K17/04
Filed: 1937-07-27
Abstract: 499,756. Steam power plant. SULZER FRERES SOC. ANON. July 27, 1937, No. 20742. Convention date, Aug. 20, 1936. [Classes 110 (iii) and 122 (iii)] A steam power plant which includes in combination at least one tubular steam generator of small liquid content, a steam accumulator and a steam engine having at least one high pressure stage, at least one medium pressure stage and at least one low pressure stage with steam leads to auxiliary consumption points interposed between the high and medium pressure stages and the medium and low pressure stages and in which the accumulator charging pipe is connected to the delivery pipes to the high and medium pressure stages through pressure control valves whilst the accumulator discharging pipe is connected to the low pressure stage through a pressure control valve. The supply of steam to the steam admission pipes of the three stages is controlled in accordance with the speed of the engine and the pressure of steam. The arrangement provides that the supply of steam to the high and medium pressure stages is closed on increases in steam pressure and the supply to the low pressure stage is correspondingly opened up. There is also further provided an arrangement whereby when the engine power falls below a predetermined value, the admission valve of the low pressure stage is completely closed and the control of the admission of the high pressure stage is taken over by a speed governor. A steam generator 1 is coupled by pipes 2 and 3 to high pressure stage 4 of a three-stage turbine unit. The exhaust from the low ptessure stage 6 passes to a condenser 8, and the condensate then goes to a feed-water tank 11. The exhaust from the high pressure stage 4 passes by pipes 13, 14 to an intermediate steam heater 15 and thence to the intermediate turbine 5. There is also a connecting pipe 16 to steam accumulator 17 and a further connection 18 to am auxiliary unit 19. The exhaust from the turbine 5 passes by pipes 20, 21 to the low pressure turbine 6 and it is also connected by pipe 22 to the accumulator 17 and through a pipe 23 with a further auxiliary unit 24. The flow of steam from the pipe 2 is controlled by valves 25, 26 which tend to be open on increases of the pressure and closed on reductions. The valve 25 opens at a lower pressure than the valve 26. In addition, the valve 25 is regulated by a speed governor so that it tends to open for reductions in speed and close for increases. In the pipe 14 is a valve 29 regulated by pressure in a pipe 30 in connection with the exhaust pipe 13. It is further regulated by a speed governor and operates precisely as does the valve 25. In the accumulator charging pipe 16 is a valve 32 regulated by pressure in the pipe 13 which tends to open on increases in pressure and close on reductions. In the pipe 21 the valve 34 is regulated by pressure in the live steam pipe 2 and operates so that on increase in pressure the valve is closed and on reduction the valve is opened. This valve also is regulated by a speed governor which tends to open the valve on reductions in speed and close on increases. Further, the valve 38 of the accumulator is regulated by pressure in the pipe 22 so that on reductions in pressure the valve opens and on increase tends to close. The arrangement is such that under normal conditions the valve 25 is controlled only by the steam pressure in the pipe 2, the valve 29 is regulated only by the steam pressure in the pipe 13 and the valve 34 limited only by the speed governor. Under abnormal conditions when speed or steam pressure vary beyond a predetermined limit, one or more of these valves is affected by the value or values which have thus varied abnormally. The valve controls are so arranged that when there is excess of steam in the pipe 13 such excess is stored in the accumulator.