| 摘要 |
PROBLEM TO BE SOLVED: To provide a water cooling device which eliminates water hammer at the time when the operation of a pump is stopped, and improves protectiveness and reliability of machinery (a computer, for instance) in a cold water circulating circuit. SOLUTION: A water cooling device comprises two pumps 1a, 1b arranged in parallel for circulating cold water between a water cooler 4 and heat loads 3a, 3b, and flowmeters 9a, 9b for each of the pumps, respectively. Speed control is effected to the individual pumps 1a, 1b through inverter circuits 8a, 8b, respectively, for supplying alternating current to make the frequency variable. Usually, one pump 1a is operated and the other pump 1b is stood by. When operation is switched to the stand-by pump 1b from the operating pump 1a on account of the occurrence of abnormality, the speed of the operating pump 1a is gradually reduced while the speed of the stand-by pump 1b is gradually increased. Further, a control unit 7 is provided for controlling each of the pumps so that the total of the flow rates indicated by the flowmeters 9a, 9b is kept at a given value.
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