Patent ID: 7267767

Claim:
A filtration apparatus comprising a filtration tank for filtering a liquid which is introduced into filtration tank, and discharging the filtered liquid to an exterior of the filtration tank comprises: filtration media contained in the filtration tank; a filtration media cleansing mechanism that comprises a hollow cleansing tank for cleansing the filtration media, and a contaminant expulsion means for expelling contaminants separated from the filtration media to the exterior to the filtration tank; wherein: the cleansing tank is a cylindrical body that hangs within the filtration tank from an upper portion thereof, the cleansing tank is provided with a lower opening at a position lower that an upper surface of the filtration media housed in the filtration tank, and a plurality of upper openings at a position higher than the upper surface of the filtration media, and the cleansing tank is provided with a screw conveyor for conveying the filtration media and the liquid, which enter the cleansing tank from the filtration tank via the lower opening, upward from the lower opening to the upper openings while scrubbing the filtration media within the cleansing tank; a mounting opening, to which the upper portion of the cleansing tank is removably attachable, provided at the upper portion of the filtration tank; and a cleansing portion, comprising the cleansing tank, the screw conveyor, and a drive mechanism for the screw conveyor, removably attachable to the filtration tank via the mounting opening, from the exterior of the filtration tank.