The product is mainly used to remove water and mechanical impurities from diesel, fuel oil, lubricating oil and other mineral oil in Marine diesel engine and land-used diesel generating sets of power station so as to reduce wear of the piston and cylinder liner for diesel engine and to avoid high-pressure pump bite of nozzle blockage hair and fault, which will prolong service life. Also used to separate two unsolvable liquid with different specific gravity or remove small amount of solid particle form liquid.