PURPOSE: To provide a filtering device capable of sufficiently washing a filter medium and improving washing efficiency, by fixing bundle of fibers to the inner wall of a filtering tower as a filtering layer by laying the bundle to cross the flow direction of water for filtration, and further, providing a supporting layer of the bundle at the downstream side of the bundle.
CONSTITUTION: In a filtering tower 1 of a filtering device, both ends of a fiber bundle consisting of long fibers longer in length than a diameter of the tower 1 are fixed by a fixing frame 4, as a filtering layer 2, to the inner wall of the tower 1 in a state that the bundle is layed to cross the flow direction of water at the time of filtration, and a pebble layer for supporting the fiber bundle is provided as a supporting layer 3 at the downstream of the layer 2 of said bundle. As a fiber mentioned above, stretchable fiber such as polyester, polyamide, and acrylic fiber is preferably selected. Thus the filtering device is constituted, where crude water is supplied to the tower 1 through a pipe 5, and treated water is taken out from a pipe 7, at the time of filtration, and air and backwash water are supplied from pipes 8 and 9 respectively, and the air and wash water are discharged from a pipe 6, at the time of washing.
IWAI MASA
NAKAJIMA ICHIROU
