The tank with filtration system by gravity, uses paper for filtration: the particles suspended in the coolant are caught in the paper filter as they pass through. The filter must be fitted on a tank, which collects the filtered coolant (which is then returned to circulation in the machine tool by means of the pump). It’s also provided a container for the impurities. Recommended especially for cases in which a high level of filtration is required (up to about 10 microns average).