WATER LEVEL CONTROLLER

PURPOSE:To prevent fluctuation of the total flow rate of supplied water at the time of switch over of pumps by distributing a total flow rate control signal issued on the basis of a water level detection signal to respective water level adjusting valves according to the operation conditions of the respective pumps. CONSTITUTION:Operation is such that the rate of transmission of total flow rate control signals to outlet adjusting valves 7-9 of pumps 4-6 on the basis of switching instructions to water level adjusting valves 10-12 issued on the basis of operation conditions of the pumps 4-6 upon the pumps 4-6 being started and stopped, is gradually changed. Since the water level adjusting valves 10-12 are under a controlled state at all times even in the course of the water level adjusting valves 10-12 being switched, the load on a steam producer 16 is changed and hence a supplied water flow rate is kept at a target value even with the amount of drain being varied. As a result fluctuation of the total supplied water flow rate at the time of the pumps 4-6 of a water supply device being switched in starting, stopping and in rotation is prevented.