| 摘要 |
PROBLEM TO BE SOLVED: To greatly enhance water quality of treated water and also to greatly reduce a discharge quantity of generated washing water for a filter medium by intermittently stopping transfer of the filter medium with respect to a continuous filtering device. SOLUTION: The filter medium A at the lower end part of a filter bed 3 is pulled out through a filter medium transfer pipe 7 and is transferred to a washing device 8 with air fed into the filter medium transfer pipe 7 from an air feed pipe 10. The feed of the air is controlled with an electromagnet valve 11. Here, a pressure sensor 17 for detecting differential pressure at a time when raw water passes through the filter bed 3, is provided in the vicinity of a feed pipe 5 of the raw water. A detection signal of the differential pressure from the pressure sensor 17 is transferred to a control device 18, and a working signal is outputted to the electromagnet valve 11 for controlling feed of the air, and a stop of the feed and a start of the feed are controlled. Like this, by intermittently stopping the transfer of the filter medium, a preferred cake layer is adequately formed on a filter bed inlet side, and filtering accuracy can be enhanced and leakage of the treated water to SS, etc., can be prevented, while the raw water is continuously filtered.
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