SAND FILTER Russian patent published in 2012 - IPC B01D24/14 B01D24/46 

FIELD: process engineering.

SUBSTANCE: invention relates to sand filter for water treatment. Said filter comprises cylindrical container housing the plate to divide it into top and bottom zones. Top zone contains filtration medium comprising single layer of sand with height H defined by formula H=a·e^b-v, where a varies from 500 to 800, b varies from 0.020 to 0.045 and filtration rate v makes 40-70 m/h. Back flushing of sand filter consists in draining filtered water contained in container top section to the level of filtration medium top surface. Air back flow is forced therein to break the crown and create air bubbles in filtration medium. Said back air-water flow is forced therein to remove dirt released in water change in sand volume and force water backflow to precipitate filtration medium. Now final flushing is performed in parallel flow to prepare said medium for filtration and eliminate dirt not removed in back flushing.

EFFECT: higher efficiency of filtration, longer life.

12 cl, 5 dwg