FILTER APPARATUS

PURPOSE:To easily perform the treatment of a slurry and to reduce the stopping frequency of filtering operation, by providing a solid-liquid separation means to a recirculation liquid system. CONSTITUTION:A recirculation liquid is recirculated and supplied to a filter 1 through a recirculation system by a pump 4 to be flowed in parallel to the surface of the filter element 2 provided in a vessel and a part of the recirculation liquid is filtered through the filter element 2 while the remainder thereof is recirculated as it is to continue filtering. During the succession of filtering or at the point of time when the suspended substance in the recirculation liquid is highoy concn., the solid-liquid separation of the recirculation liquid is performed by a solid-liquid separation means such as a sedimenting separation tank 10 to discharge a slurry of which the suspended substance is highly conc. During this time, filtering operation can be continued as it is. Filtering operation is stopped when the filtering element 2 generated clogging and other stopping causes are generated.