| 摘要 |
PURPOSE:To detect the concentration of a gas or the like automatically and rapidly to clean the same by comparing the detected concentration of the gas with a preset concentration thereof and controlling the operation of a blower. CONSTITUTION:Depending upon a result of comparison between the detected concentration of a gas or a smoke from a gas sensor 7a or a smoke sensor 7b and a preset concentration thereof in a blower consisting of a blast fan 5 and a drive motor 5 is carried out by ON-OFF control circuits 31 and 32. When the detected concentration is higher than the preset concentration, the concentration detection-comparison circuit 30 supplies power to a relay coil X1 and emits a command of continuous blasting operation of a large air flow quantity directly to a speed control circuit 32 without passing through the ON- OFF control circuit 31, and further a dust collecting unit 4 is turned ON. When the former is lower than the latter, the ON-OFF control circuit 31 is operated and a command of intermittent blasting of a small air flow quantity is emitted to the speed control circuit 32 and the dust collecting unit 4 is turned OFF.
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