| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter element in which a pleat is formed in a sheet-shaped filter medium, and a projection part is provided on each wall surface facing mutually between a ridge line and a trough line of the pleat, which is a filter element having a small dimensional error because the sheet-shaped filter medium does not slide when providing the projection part by an embossing roll or the like.SOLUTION: A filter element is described as follows. A pleat is formed in a sheet-shaped filter medium containing thermoplastic fibers, and a first projection part and a second projection part are provided on each wall surface facing mutually between a ridge line and a trough line of the pleat. The second projection part is formed between the first projection part and the ridge line of the pleat, separately from the first projection part on every wall surface, and the height of the second projection part is lower than the height of the first projection part. |
