Abstract: A method for manufacturing a filter medium comprising at least two filter plies according to which at least a first filter ply has a plurality of thermoplastically deformable fibres, by means of which the at least two filter plies are joined to each other in some areas. The method comprises forming, by means of at least two rolls of a pressing tool, at least one additional joining region configured in a web-like manner in the at least two filter plies in which the at least two filter plies are joined to each other.

Abstract: A fuel filter may include a housing having a first annular filter element and a second annular filter element. The filter elements may be arranged coaxially and offset to each other in the axial direction and may be connected in series and therefore configured to allow flow to pass through each in succession. The annular filter elements may be selectively replaceable. Adapter elements may be connected to each other and to at least one of the annular filter elements by a respective plug-in connection. One of the adapter elements may have a continuation configured to close a no-load opening in the housing when the filter element is inserted.

Abstract: The invention relates to a filter medium in the form of a wound filter with a number of adjacent tubular flow channels (5, 6) with a radial flow, which are formed from a double-layered filter web material of which one layer has a smooth embodiment and the other is corrugated. The aim of the invention is to provide the above with a simple and hence economically-produced seal, by means of which the above may repeatedly be exchangeably inserted in a filter device with a seal with little complexity. Alternatively and optionally additionally the end regions for sealing of the filter web material which forms the wound filter should permit a simplified and reliable sealing. The above is achieved by means of a material wherein felt is provided on the external circumference of the wound filter as sealing material for a radial seal within a housing.