Used for filtering and removing impurities from liquids. Working principle: After the untreated suspension is sent to the filter cartridge, solid phase particles larger than the outer diameter of the small hole on the filter cartridge are retained by the filter cartridge and sent to the bottom of the filter by a rotating brush. The filtered liquid is sent out from the liquid discharge pipe, and the filtered impurities can be discharged with the liquid flow through the impurity overflow valve at the bottom.