| 摘要 |
PURPOSE:To enable a filter medium to recover its filtration capacity continuously by the effect of the head of introduced feed water alone by providing a header for separating contaminating material from the filter medium on the main body of a filtration device including a filtration tank therein. CONSTITUTION:Pressurized water is fed to a filtration layer 2 by opening a valve 16d, then the pressurized water is fed to an ejector 15 by opening a valve 16c and 14a. Thus, the pressure of the inside of a header 9 is reduced to a negative pressure through a negative pressure pipe 14 and a siphon is formed between a rising pipe 8 and a falling pipe 13. Then, the valves 14a, 16c and 16d are closed and the feed water is sent from a feed water introducing pipe 5 to a feed water diversion chamber 3 through a feed water introducing chamber 4, which passes through flowing-out holes 3b, 3c and filtered by a filtration layer 2a, and purified water is overflowed from a overflow hole 2c. The contaminated filter medium (a) is sucked in accompany with the introduced feed water from a bottom opening part 8a into the header 9 where it is settled due to decrease of the flow rate, and is reduced to the filtration layer 12a through a recovering pipe 12. The contaminated water is discharged through the falling pipe 13 to a contaminated water tank 17.
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