| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter membrane body economically preventing adjacent mountains of pleats from tightly adhering without using any additional member, enhancing rigidity and strength in a direction along the fold of the pleats, and further enhancing back-washing efficiency. SOLUTION: In the filter membrane body 1 to be pleated, overlapping parts 10a, 10b extending in a direction orthogonally to the creases 2a, 2b of the pleats are provided. The overlapping parts 10a, 10b are made by folding at first ceases 11, 11' of the filter membrane body 1 and at second folds 12, 12' respectively. The filter membrane body 1 is made to have three plies of inner parts 1a, 1a', outer parts 1b, 1b' and intermediate parts 1c, 1c' between the first and the second folds 11, 11', 12, 12'. In the cylindrical filter membrane body, the overlapping parts 10a, 10b are installed in the vicinity of the middle between the center in a vertical direction and the upper and the lower ends so that outer pockets 13, 13' are respectively opened to the upper end and the lower end. COPYRIGHT: (C)2007,JPO&INPIT
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