LEVEL CONTROLLER FOR DRAIN TANK OF FEEDWATER HEATER

摘要

PURPOSE: To suppress fluctuation of the water level of a high-pressure drain tank, by adding a signal, where a deviation signal between the drain flow command signal of each other water level adjusting valve and its real drain flow command signal is added to the drain flow command signal outputted to each water level adjusting valve, as a control signal to the water level adjusting valve. CONSTITUTION: In case that abnormality occurs in either of normal water level adjusting valves 12a and 12b, for example, in the normal water level adjusting valve 12a and it operates in close direction, a normal water level adjusting valve drain flow signal e1 deceases, the deviation signal f1 of the drain flow of the ordinary water level adjusting valve increases. Accordingly, the drain flow command signal of the normal water level adjusting valve 12b increases by that amount, and that water level adjusting valve 12 is actuated in open direction. That is, the normal water level adjusting valve 12b on normality side works to compensate the operation of the normal water level adjusting valve 12a on abnormality side. Conversely, in case that the normal water level adjusting valve 12a on abnormality side operates in open side, the normal water level adjusting valve 12b on abnormality side operates for compensation in close direction.