JPS557953A - Starting method of drain pump in feed water preheater - Google Patents

Abstract

PURPOSE: To stabilize starting and economize labor in starting operation by preventing the pump-trip and the disorder in a water level control unit caused by the sudden changing in the level of a feed water preheater from the excess discharge amount of a drain pump at the starting time of the drain pump in the feed water preheater.

CONSTITUTION: In the stage befor a drain pump 22 is started in a feed water preheater 21, a pump exit electromotive valve 25 is perfectly closed. A main water level control valve 26 is controlled by the high water level control signal of a water level control unit 34, while an emergency water level control valve 31 by the ordinary water level control signal of a water level control unit 36. Here, when a remote-operation switch 37 is on, the drain pump 22 and the exit electromotive valve 25 are started, and when the valve 25 is minutely opened, the contact of a thermal detector is operated to keep the valve 25 at that opening. Then, the set point in a water level setting unit 33 from a high to an ordinary level and that in a water level setting unit 35 from an ordinary to a high level are respectively changed, and an ordinary water level controlling is maintained by the main water level control valve 26.

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