| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a filtration tank capable of highly maintaining a cleaning performance of a filter medium without performing the maintenance of a diffuser pipe for a long period of time. <P>SOLUTION: The inside of the filtration tank 1 is composed of a raw water supply pipe 2, an upper filter medium runoff prevention plate 3, a filtration layer 4 comprising the filter medium, the diffuser pipe 5, a filter medium support plate 6 and a treated water discharge pipe 7 etc. Therein, a circulation path 11 is formed so as to branch off from the treated water discharge pipe 7. The circulation path 11 on which a motor-operated valve 8, a pump 9 and a check valve 10 are arranged is connected to the diffuser pipe 5. An air supply pipe on which a blower 12 as an air supply source and a check valve 13 are arranged is connected to the diffuser pipe 5. In the filtration tank thus constituted, one part of the treated water is passed through the circulation path 11 and water is supplied to the diffuser pipe 5 during the filtration of the raw water. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
