| 摘要 |
PURPOSE:To clarify water by filtering in inexpensive installation and operation costs, by filtering off large impurities by a large particle size layer and medium impurities by a medium particle size layer while filtering off only small impurities by a small particle size layer. CONSTITUTION:When raw water containing impurities passes a large particle size layer 8, a medium particle size layer 7 and small particle size layer 6 in series, large impurities are filtered off by the large particle size layer 8 and medium impurities by the medium particle size 7 while small impurities by the small particle size layer 6 and clarified filtrate is discharged from a filtrate discharge pipe 3. In the regeneration process of the filter body, the feed-in of raw water is stopped while the valve 19 of an air pipe 20 and the valve 10 of a sludge-containing water discharge pipe 12 are opened and water in a filter machine 1 is flowed down to be moved to a sludge-containing water discharge tank 13. At this time or at a time when the water level is lowered below a passage preventing body 4, a stirring blade is rotated to suspend and disperse powdery filter bodies 6, 7, 8 each comprising a low specific gravity substance and, thereafter, stirring is stopped and water containing only impurities is passed through a coarse mesh metal net 5 to be moved to the sludge-containing water discharge tank 13.
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