| 摘要 |
Process and apparatus are provided for forming corrugated filter sheet by folding a long strip of sheet material into corrugations extending longitudinally of the strip, press-bending the sheet along the longitudinal fold lines of the intended corrugations; and gradually drawing in the sheet from the sides towards the center, while pushing the sheet out from each side along the fold lines, so as to form the intended corrugations, reducing the width of the sheet according to the height and width of the corrugations. |
