DRAIN INFLOW PREVENTIVE DEVICE FOR MIXED-PRESSURE/ BLEEDING TURBINE

PURPOSE:To prevent drain inflow from a mixed-pressure/bleeding system regardless of the operating state of the turbine in the caption so as to attempt reduction of the expense of installations and so forth, by installing a drain inflow preventive device between a bled-steam attemperator and the turbine. CONSTITUTION:High pressure steam generated from a boiler 1 is led to a mixed- pressure/bleeding turbine 5 via a main steam pipe 2, a main steam stop valve 3, and a main steam regulating valve 4. When process steam becomes insufficient, the mixed-pressure/bleeding turbine 5 shifts to a bleeding operation state, the steam being fed to the process via a mixed-pressure/bleeding steam stop valve 9 and a drain separator 8 after attemperated by a bled-steam attemperator 10. While, when the process steam becomes excessive during operation, the operation state changes over to mixed-steam operation. In the above constitution, the drain separator 8 is installed between the bled steam attemperator 10 and the mixed-pressure steam valve 9 in order to prevent drain inflow from the mixed-pressure/bleeding system. Due to the above construction, drain inflow is prevented in both gas mixing operation and the operation shifting from bleeding to mixing of gas.