METHOD AND APPARATUS FOR FILTRATION OF LIQUIDS Russian patent published in 1996 - IPC

FIELD: cleaning of liquids. SUBSTANCE: method involves delivery of polluted liquid under upper layer of charge while filtering from top down and subsequent washing of the upper part of the layer with washing liquid is stopped when said liquid appears at the filter casing outlet. The filter comprises a layer of granular filtering charge disposed on lower drain device, middle distributing device and upper distributing device located in the charge layer at a distance of 0.3-0.8 m from the middle distributing device. The upper distributing device has the form of pipes with holes whose size is larger than that of the layer particles by at least 3 times. EFFECT: higher efficiency. 2 cl, 1 dwg