Cluster filter is a kind of precision clarification filter with closed filtration, which adopts the design of back blowing and slag removal and integrates the tubular filter element on the liquid collecting pipe. It is also commonly referred to as tube bundle filter or candle filter. A tubular filter element is integrated inside. Shape the filter cake to a certain thickness, and after the pressure difference reaches the preset value after filtration, discharge the filtered clarified liquid through the outlet, then introduce gas to blow back the filter cake from the filter element, and then clean the filter element for the next filtration cycle.