A round filter element has a filter medium body with a wall to be flowed through by a fluid to be purified in a radial direction relative to a longitudinal axis of the filter medium body. A circumferentially extending seal carrier is arranged at or adjacent to an end face of the filter medium body. A sealing element is supported at the seal carrier adjacent to a radial outer side of the filter medium body. A positioning element extends into the filter medium body and engages with form fit a correlated housing-associated counter positioning element of a filter housing when the round filter element is installed in the filter housing. The seal carrier separates flow-tightly a raw side of the round filter element from a clean side of the round filter element when the round filter element is installed in the filter housing.

A filter device has a filter housing and a round filter element received in the interior of the filter housing. The round filter element has a filter medium body with a wall flowed through radially relative to a longitudinal axis of the filter medium body by a fluid to be purified. The round filter element has a first end disk and a second end disk arranged at opposed end faces of the filter medium body. The filter medium body has an inwardly positioned flow space inside the filter medium body that is the raw side of the round filter element. A support grid is arranged externally at the wall of the filter medium body. The filter housing has a housing cover with a flow guiding rib arranged at an inner side of the housing cover facing the interior. The flow guiding rib projects into the inwardly positioned flow space.

A round filter element is provided with an elongate filter medium body with a wall structure flowed through by a fluid to be purified in a flow direction radially relative to a longitudinal axis of the filter medium body. A seal support for a sealing element is arranged adjacent to a radially outwardly positioned outer wall of the wall structure of the filter medium body and adjacent to an end face of the filter medium body. The seal support has across a major portion of its circumference a constant radial spacing relative to the outer wall of the wall structure of the filter medium body. The seal support has at least one radially inwardly oriented indentation located at a longitudinal side of the filter medium body and provided with a reduced radial spacing relative to the outer wall of the wall structure of the filter medium body.

An air filter element has a filter medium body that has a wall to be flowed through by a fluid to be purified in a radial direction relative to a longitudinal axis of the filter medium body. The filter medium body has a first end face and an oppositely positioned second end face. The filter medium body has an elongate cross section shape with two oppositely positioned narrow sides and two oppositely positioned long sides connecting the two narrow sides. A cross section surface of the filter medium body tapers from the first end face toward the second end face. The two long sides each have an inwardly oriented radial constriction in a region of the narrow second end face, wherein, in a region of the first end face, the two long sides are formed without or at least approximately without the inwardly oriented radial constriction, respectively.

An air filter, including: an openable filter housing having an inlet for air to be cleaned, an outlet for cleaned air, a filter element exchangeably arranged with the filter housing. The filter element includes a filter medium radially surrounding and defining an interior space within the filter element and a support element secured to the filter element. The support element faces away from the filter medium and has a lateral support surface having a cylindrical section and/or a section with a cross section that changes in the direction of the element axis, whose main axis runs axially or parallel to the element axis and with which the support element is supported at least transversely to the element axis against a corresponding support section arranged on a side of the filter housing.

A filter holder (2) for a filter element (3) has an oval-shaped cross section, a receiving section (19) for a filter element (3), a fluid inlet (24), and a fluid outlet (25). The fluid inlet (24) is arranged such that an inflow direction (E) of the fluid (L) to be filtered is oriented in the direction of a lateral surface (29) of the filter element (3) such that the fluid (L) to be filtered flows tangentially around the filter element (3) in order to separate particles (33) contained in the fluid (L) onto a wall (30) of the receiving section (19) with the aid of centrifugal force.

Filter cartridges including tubular filter media having ovate cross-sections and filter systems using the ovate tubular filter cartridges are described herein. The inner perimeters of the ovate cross-sections of one or more of the filter cartridges may be asymmetric, i.e., the inner perimeters of the cross-sections of the tubular filter media in the filter cartridges may have no lines about which they are symmetric. The inner perimeters of the ovate cross-sections of the tubular filter media in one or more of the filter cartridges may have only one line of symmetry

A support structure for an interior volume of a construction of pleated media is operably oriented in the interior volume and structurally supports the media. The support structure can pass directly through an innermost 60% of the interior volume. It can have a void volume not more than 80%. It can be inner liner-free and extend in a non-curved path. It can include a first sheet and second sheet of porous material. At least a first brace construction secures the first sheet and second sheet together and in spaced apart, opposing relation. The support structure can include a pleated construction having pleats extending in a direction non-parallel and angled to the direction of pleats of the pleated filter media. The support structure can be molded spacers.

A round filter element has a filter medium body with a wall to be flowed through by a fluid to be purified radially relative to a longitudinal axis of the filter medium body. The filter medium body has a longitudinally extending cross-sectional shape in a direction transverse to the longitudinal axis. The filter medium body has a first end face and a second end that are axially oppositely positioned relative to each other in a direction along the longitudinal axis of the filter medium body. A first end disk and a second end disk are arranged at the first and second end faces, respectively, and have the same cross-sectional shape. The filter medium body has a twist by being twisted about the longitudinal axis such that the axially oppositely positioned first and second end faces of the filter medium body are angularly displaced relative to each other.

A filtration system includes an air cleaner housing and a filter element. The air cleaner housing includes a base and a removable cover. At least one of the base or the cover defines a cavity and a protrusion extending into the cavity. The filter element is disposed within the cavity. The filter element includes a plurality of media blocks each including a pleated filter media. The plurality of media blocks are arranged in arch shapes of approximately equal inner radii. The plurality of media blocks are coupled to each other along opposing edges that extend along a pleat direction of the pleated filter media. The media blocks together define at least one void that extends along the protrusion. The protrusion occupies a portion of the void.