| 摘要 |
PROBLEM TO BE SOLVED: To take in clean air for a long duration without cleaning or changing an air filter at the time of ventilating air for a building. SOLUTION: In a ventilation fan 8 provided with a propeller fan 4 and an air filter 11 and installed in a suction route having an air intake and an air outlet, the air filter is an inertial separation type dust collecting filter and a dust eliminating route 10 having three apertures: an aperture formed in the lower part of the dust collecting filter, an aperture in the air intake side, and an aperture in the air outlet side is installed. The dust eliminating route 10 is provided with a first check valve 13 to inhibit dust from being discharged to the aperture in the air outlet side and a second check valve 14 to inhibit air from flow in to the aperture in the air intake side. |
