| 摘要 |
PROBLEM TO BE SOLVED: To permit the intake of clean air for a long period of time without cleaning or replacing an air filter upon the ventilation of a building and the like. SOLUTION: In a ventilating fan, equipped with at least a propeller fan 4 and an air filter 11 in a suction air passage equipped with an air inlet port and air outlet port, the air filter 11 is an inertia separation type dust collecting filter and equipped with a dust removing passage 10, provided with an opening, equipped below the dust collecting filter 11, and two openings at the side of the air inlet port, while a non-return valve 13, precluding the inflow of air from the opening at the side of the air inlet port, is provided in the dust removing passage. |
