Abstract: A filtration device includes: a filtration tank having a raw water inlet pipe and a backwash water discharge pipe connected to an upper portion thereof, and a treated water discharge pipe, a backwash water inlet pipe, and a backwash air inlet pipe connected to a lower portion thereof; a strainer provided in the filtration tank and having a plurality of water passage holes formed on a side surface thereof and a lower side in communication with the treated water discharge pipe; a filtration unit including a fiber filter medium forming a filtration pore layer on the outer circumferential surface of the strainer, an upper support portion coupled to an upper side of the fiber filter medium, and a lower support portion coupled to a lower side of the fiber filter medium; and a filtration control unit having a cylinder disposed inside the strainer and a piston elevating from the cylinder and controlling the porosity of the fiber filter medium by compressing or relaxing the fiber filter medium with respect to the stra

Abstract: A lift type pore-controllable fiber filter includes a filter tank, a strainer coaxially formed as a porous tub in the filter tank, extending to an outside of the filter tank at a bottom thereof to communicate with a treated water drain pipe, and having a piston guide recessed in an axial direction at an upper portion thereof, a lifting driver including a cylinder and a piston, an upper filter material fixing plate having fixing means, fixed to the piston above the strainer, and working in collaboration with reciprocation of the piston, a lower filter material fixing plate having fixing means and fixed below the strainer, and at least one fiber filter material fixed to the fixing means of the upper and lower filter material fixing plates at upper and lower ends thereof respectively, and forming filtering pore layers on an outer circumference of the strainer.