The series of steel gravity valveless filter tanks are widely used in surface water purification, iron and manganese removal from groundwater, side - stream filtration of circulating water, removal of suspended impurities from production wastewater, subsequent filtration after biochemical treatment and secondary sedimentation tank treatment of organic sewage, and filtration of indoor swimming pool water.

It adopts a small - group drainage system, with forward and gravity - type filtration. Backwashing is carried out under the action of siphon head using the water volume in its own clean water area. Therefore, there is no need to install a backwashing pump or a backwashing water tower like high - speed filters, medium - speed filters, mechanical filters, and ordinary rapid filters. Inside the filter tank, a relatively large number of flushing clean water pipes are used and arranged at the centroid axis of their respective area figures. Therefore, the backwashing water is evenly distributed. The filtered water is collected by multi - leg water collection troughs in the clean water area. Therefore, after the filter tank is in place, it has strong adaptability to the levelness of the weir crest of the water collection trough, thus enabling uniform water collection.