VENTILATION FAN AND ITS DRIVE METHOD

摘要

PROBLEM TO BE SOLVED: To purify the outside air without cleaning or exchanging a filter for a long time by temporarily exposing a part or a whole part of a dust- collecting filter including a lower part of the dust-collecting filter of inertial separation type to a gas inlet side of a suction passage. SOLUTION: A round pipe sleeve 3' is provided in a hole 2 of a wall 1 on which a ventilation fan 8 is provided, and the pipe sleeve 3' is provided with a propeller fan 4 and a dust-collecting filter 9 of inertia separation type. A lower end of the dust-collecting filter 9 is exposed to the outside of a gas inlet 10 of the pipe sleeve 3' to keep the lower end of the dust-collecting filter 9 in an open condition 9. The air supply 13 is generated by turning the propeller fan 4 in the reverse direction, a part of the dust is discharged as the air 14 containing the dust, and a part of the air supply 13 is discharged as the filter- cleaned air 15 outside the gas inlet 10 through the dust-collecting filter 9. The outside air can be purified without cleaning or exchanging the dust-collecting filter 9 for a long time.