| 摘要 |
PURPOSE:To reduce the slapping noise upon the operation of the air intake and prevent the cleaning liquid from dropping from the air intake at the time of the localized ventilation immediately after the completion of the cleaning process by providing a time lag between the timing of rotational motion of a baffle plate and the timing of start or stop of the ventilation fan. CONSTITUTION:Upon turning on the ventilation switch, the ventilation fan 10 is operated, and one second later, a solenoid 14 is energized to rotate the baffle plate 7 to open the air intake 2. As the ventilation fan 10 is first operated, a suction force is acting on the baffle plate to counter its rotational motion. The pulling force is larger when the plunger 17 of the solenoid 14 is projecting,a nd by reducing such, the rotational speed of the baffle plate 7 is reduced so as to reduce the slapping noise between the baffle plate and the lower part 18 of air intake. When a localized ventilation is desired during or immediately after the cleaning process, as the ventilation fan 10 is first operated and the baffle plate 7 rotates while the air is being drawn from the air intake 2, the cleaning liquid that tends to trickle down on the inner wall of the smoke ventilation device 1 is blown or remains stationary due to the air flow, the cleaning liquid does not drop from the air intake out of the device.
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