Process for manufacturing a filter and apparatus for carrying out the process

摘要

A filter comprising a composite sheet (6) bent in the form of a zigzag and composed of a laminate of at least two monolayer sheets (60), in which the bent portions are fusion-welded, is provided in order to improve filtering properties while carrying out the composing and bending processes in one process. A device for manufacturing the filter is also provided. The device comprises, for example: a pair of star-shaped gear type ribbed rollers (2) engaged with each other for heating the composite sheet (6) to temperatures suitable to fusion-weld the same at the front end of the gear while bending the composite sheet like a zigzag having a bent width corresponding to the depth or height of the gear; star-shaped gear type bending roller (3) for further bending the heated composite sheet like a zigzag; and a pair of heating plates (4) positioned opposed to each other at a distance corresponding to the bent width of the zigzag. In this device, the composite sheet (6) is selectively and linearly heated and fusion-welded at the bent portions in contact with the front end (20) of the gear (2) while being bent, and it is further bent by the bending roller (3) and then passed through between the heating plates (4) where the composite sheet is heated and fusion-welded at the bent portions from the outer side thereof.