| 摘要 |
PURPOSE:To extend the life of a filler of a ventilator without restraining the wind pressure resistance during operation of the ventilator by a method wherein a filter element of the filter has a larger oily dirt retaining capacity at the low,cr part than at the upper part. CONSTITUTION:When a ventilator 1 is operated with a filter 4 in use, oily dirt caused by soot, etc., begins to attach on the whole surface of the filter 4 at first, but after a long term operation, the amount of oily dirt caught by a filter element 6 exceeds the limit of the dirt retaining capacity of the filter 4 and oily dirt begins to fall down. This phenomenon is more remarkable at time filter lower part 6a, however, the filter lower part 6a has a double-layered filter element 6 to increase the oily dirt retaining capacity, so that oily dirt falling down from the upper part can be retained by the lower part 6a. Therefore, oily dirt does not fall down from the filter 4 unless the amount of oily dirt exceeds the oily dirt retaining capacity of the lower part 6a, resulting in an extension of the life of the filter 4. In addition, if the lower part 6a is provided with a multiple-layered construction, the retaining capacity of oil falling down from the upper part can be increased. |
