Knockdown type filtering device

Claim 1

A knockdown filtering device for use in a water tank comprising a plurality of filtering units, a connecting pipe on which said filtering units are detachably supported in adjacent parallel relation, said connecting pipe having openings for receiving waste water in said tank, water inlet means coupled to said connecting pipe at one end thereof for introducing the waste water to said filtering units for flow therethrough in succession, a common drain passage communicating with said filtering units for receiving purified water therefrom, and air lift means coupled to said drain passage for circulation of the purified water back into the tank, each of said filtering units comprising a filtering chamber filled with filtering material and an outlet connecting said filtering chamber with said drain passage, said filtering chambers having openings for communication of one chamber with an adjacent chamber for flow of water from the inlet means through said chambers, each of said chambers being provided with a groove, said connecting pipe being detachably fitted in the grooves of adjacent chambers to extend therealong for assembly of the chambers on said pipe, said common drain passage being formed by individual drain passages provided in said chambers below said groove, which drain passages are assembled in communicating relation when the chambers are mounted on said connecting pipe in communicating relation with one another.