GB721099A - Steam generating plants which employ electric motors - Google Patents

Abstract

721,099. Electric fluid heaters. SULZER FRERES SOC. ANON. May 11, 1953 [May 14, 1952]. No. 13120/53. Class 39 (3). In steam generating plants employing electric motors for driving auxiliaries such as pumps and blowers and regulated by control resistances 1-4, these resistances serve as heaters for a fluid employed in the plant, for generating or superheating steam, for pre-heating feed water, furnace air or liquid fuel. The control resistances comprise immersion heaters or electrode boilers. In the figure, the broken line shows the path of the water and the thick continuous line that of the steam. Feed water is supplied by a pump 10 from a vessel 9 to a boiler 5 supplying steam to a turbine 6 driving a power absorber 7 such as an electric generator. Steam from the turbine is condensed in a condenser 8, whence water flows to the feed vessel 9. Immersion heater 1 in a small boiler generates steam supplied to the boiler 5 through a water separator 11. Heater 2 is supplied with water tapped off from a secondary feed water pipe and provides low pressure steam injected into the secondary steam pipe pipe leading from the condenser 8. Heater 3 vaporizes. and superheats condensate in the closed circuit of the secondary steam superheater 12. Heater 4 pre-heats combustion air for the boiler 5. In using water as the control resistance in an electrode boiler, the distance between the electrodes may be adjusted and the current may flow through water jets divided against one electrode from nozzles in a counter-electrode. An asynchronous motor may drive an induced draught blower producing a subatmospheric pressure in the combustion chamber, the speed of the motor being adjusted automatically in dependence on the adjustment of a flue gas valve on the pressure side of the blower. A slip ring motor may be used for the high pressure feed pump. Control resistances of two or more motors may be incorporated in the same heater.