MAIN STEAM PIPE WARMING STRUCTURE OF STEAM TURBINE

摘要

PURPOSE:To warm economically a main steam pipe whenever a stopped steam turbine is started by providing an automatic drain valve opened by a start preparing signal of the turbine and closed by a predetermined requirement after the start in the main steam pipe. CONSTITUTION:Drain pipes 9, 19 provided with motor-driven drain valves 8 respectively are provided in branched main steam pipes 7b, 7c. The motor drain valve 8 is opened by a start preparing signal of a starter of turbines 1, 10 and closed by a signal of reaching a predetermined value of the rotational frequency of a turbine wheel shaft after the start. Here, steam from a steem supply source 6 flows through the main steam pipe 7 by opening the motor drain valve 8 to be discharged through the drain pipes 9, 19 while warming then the main steam pipe 7. Thus, whenever the turbine 1, 10 are started, the main steam pipe 7 can be warmed and an amount of steam exhausted from the motor drain valve 8 becomes necessary minimum so that the economy of a plant is improved.