| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional system, wherein when a filter becomes clogged, the temperature in a ventilation duct increases, and thus a difference between the outside temperature and inside temperature is detected to determine, based on a fixed threshold, whether the filter has been clogged, in which case the increase in temperature difference is small and a temperature detecting circuit fluctuates, which make it difficult to detect the difference and is likely to cause malfunctions, and the consideration, for effective detection in the system of cooling two or more heat generating bodies, is not taken. SOLUTION: A control device, using two or more fans, adopts the system in which the filter also serves as the ventilation duct. In this system, a temperature detection circuit is disposed on the side of a low-pressure control fan in the duct, because the current of air in the duct is drawn by a higher-pressure control fan, when the filter is clogged. Since with this configuration the difference between the outside air temperature and the inside air temperature is increased, to immediate detection of the clogging of the dustproof filter becomes possible. COPYRIGHT: (C)2007,JPO&INPIT
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