FILTER Russian patent published in 2001 - IPC

FIELD: liquid purifying equipment. SUBSTANCE: filter has cylindrical filtering grid, back washing pipe concentrically mounted within filtering grid for rotation and provided with inlet opening for liquid to be filtered at one end of tube and outlet opening for discharge of filtered liquid and supply of washing water at other end of tube. Injection openings in tube wall are arranged at predetermined interval in vertical plane and adapted for supplying washing water. Lock valve mounted in the vicinity of inlet opening is adapted for providing passage of filtered liquid into tube for back washing and preventing back washing water from flowing from tube inner cavity via inlet opening. Device imparting rotational motion to tube relative to its axis for providing back washing may be blade or set of offset injection openings for passage of back washing water. EFFECT: increased time of useful operation of filter and improved quality of filtered liquid. 6 cl, 14 dwg