The liquid enters the filter through the inlet manifold and is evenly distributed to each filter cartridge for filtration, with the fluid flowing from bottom to bottom. Through the filter element, the filter element retains solid particles, and the filtered water flows out from the top of the filter cartridge after passing through the filter element, and then flows out after collecting through the outlet header. Filters enter downstream equipment. With the continuous accumulation of particles on the surface of the filter element, the differential pressure of the filter gradually rises. When filter differential pressure When the set value is reached, the import and export valves are controlled automatically at the same time. After the system program receives the differential pressure induction, the import and export valves are the same. When closed, the cleaning port on the side of the filter cartridge is opened, and the filter backwashing is controlled. After backwashing, the differential pressure of the system recovers the initial pressure difference.