| 摘要 |
PROBLEM TO BE SOLVED: To stably operate a boiler even in loaded areas before and after an original switching point in a flow-through operation and a recirculation operation. SOLUTION: The boiler operation switching device is equipped with: a normal function generator 13 for outputting a water supply flow rate program [03] signal; a flow-through operation function generator 12 for outputting a numeric value invariant signal corresponding to a minimum water supply flow rate [02] to be fed from a water supply pump and a recirculation system to a furnace; a recirculation operation function generator 11 for outputting a minimum water supply flow rate [01] signal of a numeric value higher than the water supply flow rate program [03]; a switching means 16 for selecting by a manual operation one signal out of the signal from the flow-through operation function generator 12, and the signal from the recirculation operation function generator 11; and a high side selection circuit 15 for comparing the signal passed through the switching device 16 with the water supply flow rate program [03] signal of the normal function generator 13, and setting the signal with a larger numeric value as a water supply flow rate command [05] signal. A water supply pump and a circulation pump can be operated based on the water supply flow rate command [05] signal. COPYRIGHT: (C)2009,JPO&INPIT
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