| 摘要 |
PURPOSE:To reduce unstable phenomena in heat pipes and consequently prevent the thermal stress and deformation accompanying said phenomena by a method wherein a flow rate of scavenging steam, which is the heating steam of the heat exchanger to supply reheated high pressure turbine exhaust steam to a low pressure turbin, is optimum-controlled. CONSTITUTION:The flow rate of scavenging steam is controlled by a scavenging steam exhaust valve 11 in proportion to the opening of a drainage exhaust valve 10 by means of a controlling unit 50 (not shown in fig.). In the controlling unit 50, the flow rate of drainage GD 23 is calculated by an arithmetic unit 22 in proportion to the opening of the drainage exhaust valve 10. Next, the flow rate signal of the flow rate GD 23 is transmitted together with the flow rate signal of the flow rate of heating steam GS 25 to an adder 24 in order to calculate the flow rate of scavenging steam GV 26. Further, a scavenging steam ratio GV/GD is calculated by a divider 27. The set value set at a scavenging steam ratio setter 28 and the scavenging steam ratio GV/GD are compared with each other at an adder 29 and a valve opening signal AV 31 is calculated by an arithmetic unit 31 based upon a deviation signal alpha of said set value and ratio GV/GD and given as an operating signal to the scavenging steam exhaust valve 11 in order to control the flow rate of scavenging steam. |
