Various example embodiments relate to a filtration system. The filtration system comprises a housing having a first housing end and a second housing end. The housing defines a central compartment therein. The housing comprises a first alignment portion disposed on the first housing end. The filtration system further comprises a filter element positioned within the central compartment of the housing. The filter element has a first filter end and a second filter end. The filter element comprises filter media and a second alignment portion disposed on the first filter end. The second alignment portion is complementary to the first alignment portion. The installation of the filter element within the housing causes the first alignment surface and the second alignment surface to align to provide for engagement of a radial seal between the filter element and the housing.

A flat air filter element for an air filter has a filter medium of cellulose material and a sealing element extending circumferentially about the filter medium. Sealing element and filter medium have at least one recess at an outer contour of the flat air filter element. The sealing element has a circumferentially extending holding groove to be engaged by a housing part of a filter housing. The filter housing has a housing pot, a housing cover to cover the housing pot, and a closure element for closing the filter housing. The flat air filter element is secured in the closed state of the filter housing by circumferentially clamping the sealing element between housing pot and housing cover. The circumferentially extending holding groove of the sealing element is engaged by housing pot or housing cover. The closure element of the filter housing is arranged in the region of the recess.

An air filter element includes (a) an open filter interior having a first closed end and a second open end opposite the first closed end; the second open end having an air flow aperture therethrough; (b) filter media provided in a pleated configuration and arranged around the open filter interior between the first closed end and the second open end; (c) a seal arrangement positioned at the open end of the filter element and includes an inner perimeter radial facing surface and an opposite, outer perimeter radial facing surface, wherein the inner perimeter radial facing surface includes a seal surface, and wherein one of the inner perimeter radial facing surface and the outer perimeter radial facing surface is a circular surface and the other of the inner perimeter radial facing surface and the outer perimeter radial facing surface is a non-circular surface.

The present disclosure relates to filter assemblies. The features described and characterized are typically applied in gas (for example, air) cleaner assemblies. A typical use is in air cleaner assemblies for vehicles or other equipment. The techniques described relate, at least in part, to provision of assemblies with preferred configurations for convenient servicing and operation, while ensuring a proper cartridge is appropriately positioned, oriented and secured for use. Many of the techniques relate to arrangements in which features at opposite ends of a housing and/or cartridge are eccentrically positioned as described.

A method for manufacturing a filter (1) for gas masks includes providing a flat paper and folding the paper into a pleated preform. The filter element (2) is separated from the pleated preform (6) and is inserted into a housing (3). The inserted filter element (2) is connected to the housing (3) at least at some points. This filter elements (2) may have a polygonal outer contour, upon separating the element from the pleated filter preform (6). A foam and/or an adhesive is applied to an outer edge of the filter element (2), arranged on the circumference of the filter element, for an at least partial sealing of an edge (5). This establishes a connection to the housing (3) in at least some sections.

Various example embodiments relate to filter elements. One such filter element includes filter media having a plurality of flow channels. Each of the plurality of flow channels comprises an inlet having an inlet height and an outlet having an outlet height. The inlet height is larger than the outlet height. The filter media defines an inlet face having an inlet face area and an outlet face having an outlet face area. The inlet face is structured to receive air to be filtered. The outlet face is structured to output filtered air. The inlet face area is larger than the outlet face area.

Panel filter elements having a pleat block and a seal member are described. The panel filter elements are arranged such that the seal members and pleat blocks can have curved and/or angled elements. The seal member of a filter element may be curved, angled, twisted, and/or has a varying cross-section. The inlet and outlet faces of the pleat block of the filter element may be curved and/or twisted instead of planar. In some arrangements, both the seal member of the filter element and the faces of the pleat blocks can be curved and/or twisted. The described filter elements may be may be flexible, such that the shape of the filter element and/or seal can conform to the shape of a filter housing, or rigid, such that the shape of the filter element remains substantially the same before and after installation into a filter housing.

A flat filter element for filtering a fluid may include a filter body made up of a folded filter material. The filter element may also include a circumferential edge and a side edge running in a circumferential direction along the circumferential edge. The side edge may have at least one strip portion, running along the side edge, with a side strip that may be separate from the filter body and arranged on the filter body. The side edge may also have at least one adhesive portion running along the side edge for sealing the filter body. The at least one adhesive portion may be formed by gluing of least two folds, adjacent along the side edge, in a region of the side edge.

The invention pertains to an air filter element comprising: a filter medium pack comprising a filter medium, said filter medium pack having an optionally substantially planar first side and an optionally substantially planar second side, said first side and second side optionally being parallel; and a guiding rim comprising a sealing surface having at least a radially oriented component, arranged on at least one of said first side and said second side, wherein a circumference of the or each guiding rim comprises at least one convex portion and at least one concave portion; and wherein a contour of said filter medium pack corresponds to said convex portion of said guiding rim and at least part of said concave portion. The invention also pertains to a method for producing an air filter element.

A filter element for filtration and dehumidification of a gas has at least one filter medium body with an outflow side delimiting a clean-side flow chamber. A dehumidification unit is arranged downstream of the at least one filter medium body in a flow direction of the gas in the clean-side flow chamber. A carrier body accommodates the at least one filter medium body and the dehumidification unit. The dehumidification unit is connected flow-tightly to an outflow opening of the clean-side flow chamber. The dehumidification unit is arranged in the clean-side flow chamber at a spacing relative to the at least one filter medium body.