| 摘要 |
PURPOSE:To permit the stable idle operation by a little quantity of cooling steam by allowing said cooling steam to circulation-flow in a low-pressure turbine vane wheel, controlling the internal pressure of a low-pressure wheel chamber, outlet temperature of a high-pressure wheel chamber or flow rate to each constant value. CONSTITUTION:Switching from the normal operation to idle operation of a low-pressure turbine vane wheel is carried-out by setting a low-pressure steam reducing valve 9 and a stop valve 13 into closed state and other valves into opened state by the instruction supplied from an instruction board 18. When cooling steam is sent reversely into the low-pressure wheel chamber of a low- pressure turbine 2 form either a cooling steam 22 (a) system or an intermediate- pressure steam 20 (b) system, said steam flows into the high-pressure wheel chamber side. Though temperature rise of steam occurs at this time, the quantity of cooling steam can be reduced, since the temperature gradient is made equal to that in the ordinary operation. Further, the internal pressure of the low- pressure wheel chamber, the outlet temperature of the high-pressure wheel chamber, or the flow rate can be controlled to each constant value by a pressure control valve 11 or 11' and a temperature or flow-rate control valve 15. |
