| 摘要 |
PURPOSE:To prevent back flow of steam by cutting steam supply to a part of low pressure turbines at the time of low load and separating said part of low pressure turbines from the flow of steam of running system, in a power generating steam turbine provided with plural low pressure turbines. CONSTITUTION:Boiler feed water 2 is guided to enter a boiler 1 to become high temperature and high pressure steam, and to enter a high pressure turbine 3. The exhaust in the high pressure turbine 3 is returned to the boiler 1 and heated by a reheater 4, to be raised in temperature and guided to enter a medium pressure turbine 5. The exhaust of the medium pressure turbine 5 enters respective wheel chambers of two independent low pressure turbines 7a, 7b through a steam pipe 6, and the exhaust from each wheel chamber is condensed in a condenser 9 and returned into the boiler feed water system from a discharge water pipe 10. Then, at the time of partial load running, flow path of the steam pipe 6 to the final stage low pressure turbine 7b is stopped by a cut-off valve 15 to change over to single running of the low pressure turbine 7a on the upper flow side, and back flow to the final stage low pressure turbine 7b is prevented.
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