Method for manufacturing an edge element for filter insert

摘要

The end folds of a zigzag filter pack (4) are reinforced by an extruded plastic strip (2) with an elastic modulus greater than 1000 N/mm2. Integrally attached is an elastic seal (3) made of a plastic with a Shore hardness of less than 100. The assembly is made as an extrusion and wound up continuously on a package of 1 to 1.5 m diameter. Cut lengths are attached to a fold (5, 6) of the filter pack. An Independent claim is also included for the process of making both the reinforcing strip and the seal together as a single extrusion, preferably as a double strip with mirror image assemblies back to back and a weak joint line for subsequent splitting. The assemblies are stored as a circular package and only cut to length just before fitting to the filter pack, preferably by ultrasonic welding. The reinforcing strip can be turned over the side on a film hinge (8) and joined to the side (10) of the last fold of the filter pack to act as protection (9) and locating device (12). More than one sealing lip (3) can be used.