Abstract: A filtration device which comprises a frame having a plurality of nozzles that are opposed but shifted aside relative to one another. The boxlike frame is composed of a first frame having a U-shaped cross-section and a second frame having an inversely U-shaped cross-section, both the first and second frames being provided with joining projections. A plurality of intake tubes in conical shapes are arranged on the inside of the first frame in a manner like a checkered pattern and the cross-section of each intake tube is enlarged in the suction direction and reduced in the exhaust direction. A plurality of outlet tubes projected downward and having fins at their lower ends are attached to the inside of the second frame. These outlet tube group is also arranged like a checkered pattern and shifted aside relative to the other nozzle group on the first frame.