| 摘要 |
PROBLEM TO BE SOLVED: To prevent filter medium from flowing out of the filter casing even at the time of performing the filtration of water and the backwashing of a filter layer by placing two supporting materials opposite to each other between a water supply port and a water discharge port of a filter casing and interposing a filter medium between these supporting materials, in a filter. SOLUTION: In this filter, a filter casing 6 is provided between a water supply port 7 and a water discharge port 8 with an upper supporting material 9a, a lower supporting material 9b and a filter layer consisting of a granular filter medium 10 interposed between the upper and lower supporting materials 9a and 9b. For example, at the time of purifying and reusing domestic bathtub water, when the bathtub water is introduced into the water supply port 7, large particles in the bathtub water are captured on the upper supporting material 9a and small solid particles, etc., are captured and filtered by the granular filter medium 10. When the granular filter medium 10 and the upper supporting material 9a are clogged with solid particles, etc., and accordingly, at the time of performing backwashing for regenerating the filter layer, backwashing water is passed through the granular filter medium 10 from the water discharge port 8 to wash the granular filter medium 10 and then, discharged from the water supply port 7. At this time, solid particles stuck to the granular filter medium 10, together with the used backwashing water, are discharged from the water supply port 7, however, the granular filter medium 10 is prevented from flowing out of the filter casing 6 by the presence of the upper supporting material 9a within the filter casing 6.
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