Pleated filter insert and method of manufacture

Abstract

A method for manufacturing a filter insert, configured as a folding pack and made of thermoplastically bondable nonwoven material, such that a planar filter medium is first folded and then immobilized in a permanent form at a preset fold spacing by delivery of energy and subsequent cooling, such that after the process step of creating a defined fold spacing, the two outer edges of the folded pack are positively clamped into comb-like profiles, substantially corresponding to the fold geometry and dimensions of the folded pack and engaging in toothed fashion into the top and bottom of the folds, the spacing between which is chosen to be the same as or slightly less than the thickness of the nonwoven fiber fabric, wherein the folded filter material projects beyond the comb-like profiles at each outer edge a distance less than 1 times the fold spacing, wherein a sealing band, corresponding in width substantially to the height of the folds, is laid on the outer edges on the long sides, and in each case compressed by means of pressure elements acting laterally thereon and at the same time thermally bonded, with energy delivered via the pressure elements, to the outer edges of the filter material. The bond points are pressed together and immobilized until they cool. The profiles are then removed, and the folded pack is cut to length.