PLEAT FILTER, BALLAST WATER TREATMENT APPARATUS USING THE SAME AND BALLAST WATER TREATMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a pleat filter capable of preventing fracture caused by use, and contributing to stable use for a long period, and to provide a ballast water treatment apparatus using the same.SOLUTION: A pleat filter is obtained by shaping a filter base material having folds with repeated crest parts and trough parts into a cylindrical shape in which the ridge line direction of folds agrees with the axial direction. In the pleat filter, assuming that the thickness of the filter base material is t(mm), and that the interval between folds on the inner peripheral side of the cylindrical shape is D(mm), the following formula (1) is satisfied: 3t≤D≤4t...(1).