IMPROVEMENTS TO FILTERS WITH GRANULAR MATERIAL BED, IN PARTICULAR FOR WATER TREATMENT

摘要

The invention concerns a device for intake of water into a granular material bed filter such as filters used for water treatment for eliminating suspended materials comprising means for injecting water and air through the filter bed and a channel for evacuating filtered water and a trough for evacuating wash-water. The invention is characterised in that it comprises two superposed overflow levels: a lower level (6) for intake of filtered water and a higher level (7) for intake of dirty wash-water, means being provided for shifting from one overflow level to the second overflow level, the channel (8) evacuating treated water and the trough (9) evacuating dirty water after washing being superposed.