| 摘要 |
PURPOSE: To attach an air filter element simply to a paper frame while saving labor in paper frame forming work in a production process of a paper air filter. CONSTITUTION: In the air filter which is made by bonding the whole fringe part of an air filter element 6 which is folded zigzag to the whole inner surface of a paper frame 2 formed into a picture frame shape, the paper frame 2 is constituted from square paper tubes 10a, 10b, and both ends of the tubes 10a, 10b are connected by connection means respectively to form the frame 2 into a picture frame shape. |
