GB208841A - Improvements relating to steam turbines - Google Patents

Abstract

208,841. Baumann, K., and Metropolitan-Vickers Electrical Co., Ltd. Oct. 13, 1922. Feed-water, heating.-To avoid dangerously high temperatures at the lowpressure end of a turbine when running under a light load, steam is withdrawn from the inlet end, or from a high or intermediate-pressure stage, and used for heat feed-water. A by-pass 5, Fig. 1, controlled by a valve 6, connects the steam inlet pipe 7 of the turbine 1 through the steam space of a surface-type heat-exchanger 8 with a circumferential belt 9, leading to a low-pressure stage. Another by-pass 10, controlled by a valve 11, connects two points beyond the extraction pump 4 in the condensate or feed-water pipe 12, controlled by a valve 11<a>, through the water space of the heat-exchanger 8, and a drain 17 connects the lower part of the steam space of the heat-exchanger 8 and the steam space of the condenser 3 In a modification, a heat-exchanger of the direct contact or jet type is used. Instead of being tapped from the inlet pipe, the steam may be withdrawn from a belt surrounding a high or intermediate pressure stage. Fig. 4 shows the invention applied to a turbine fitted with a progressive feed-water heating system, the feed-water under normal operation being passed through heaters 19, 18 and therein heated by steam tapped from belts 23, 22. By opening a valve 27 in a pipe 26, under light load conditions, steam from the intermediate-stage belt is passed through and cooled in the heaters 18, 19 and led by the pipe 21 to the low-pressure stage.