Laser welding method and filter element produced by it
AssigneeCarl Freudenberg KG
InventorsEckart Driesen, Ulrich Schloer
Life of this patent
Estimating the term…
Abstract
A method is provided for connecting a filter medium to a connection element, wherein the filter medium and the connection element are brought into contact with each other and connected to each other by exposure to laser radiation. The connection element may be welded to the end faces of filter folds in strips having a width of 1 mm. The connection element may include a laser light-absorbing layer and a laser light-transparent layer. The filter medium and connection elements may comprise nonwoven fabrics.
Claims19
Method for connecting a filter medium to a separately formed V-shaped flap or strip-shaped connection element, the filter medium and the connection element being brought into contact with one another and being connected to one another as a result of the action of laser radiation from a laser radiation source, the filter medium comprising a folded sheet-like layer of thermoplastic nonwoven including folded pleats and fold end faces, the separately formed connection element comprising a thermoplastic nonwoven, wherein at least one separately formed connection element is connected to the fold end faces of the sheet-like layer, the separately formed connection element being pressed against the filter medium and providing a contact point, wherein either one or the other of the separately formed connection element or the filter medium absorb said laser radiation and melt and flow into the thermoplastic nonwoven of the other material and said contact point has a fused region depth of 1 mm or less and does not include a compressed region or permanent deformation as between said contact point and said filter medium.
Filter element, comprising at least one filter medium and at least one separately formed V-shaped flap or strip-shaped connection element, the filter medium and the separately formed connection element being pressed against one another at contact points which comprise a region of fused thermoplastic generated by laser radiation, said contact point having a fused depth of 1 mm or less and not including a compressed region or permanent deformation, the filter medium being designed from a folded flat sheet as a concertina including folded pleats and fold end faces, and the filter medium and separately formed connection element comprising thermoplastic nonwovens, wherein the fold end faces are connected to the separately formed connection element, wherein one or the other of the separately formed connection element and the filter medium absorb said laser radiation and melt and flow into the thermoplastic nonwoven of the other material the connection element being of multi-layer design, at least one layer being transparent to laser light and a further layer absorbing laser light, the filter medium including a layer absorbing laser light.
Dependencies are inferred from the claim text.