Abstract: A filter element for filtering fluid has a filter bellows arranged around a longitudinal axis and enclosing an interior. The filter bellows has a first end and an opposed second end. The filter bellows has a first end plate open toward the interior at the first end and a second end plate at the second end. A circumferential seal contour is arranged at the first end plate and rises (extends) in the longitudinal direction from the first end plate. The circumferential seal contour has a locally limited recess in radial direction and protrudes in a region of the locally limited recess inwardly past an inner circumference of the filter bellows. A filter device has a filter housing with fluid inlet, fluid outlet, and a receiving space accommodating the filter element such that a raw side at the fluid inlet is separated from a clean side at the fluid outlet.

Abstract: A ring filter element assembly includes a first ring filter element with a first filter medium body and a second ring filter element with a second filter medium body, the second ring filter element is arranged inside the first ring filter element. An outer wall surface of the second filter medium body and an inner wall surface of the first filter medium body adjoin each other in an interface region and a positioning device arranged therein angularly positions the first and second ring filter elements relative to each other. The positioning device has an engagement element extending radially outwardly to engage a first counter engagement element of the first ring filter element and/or radially inwardly to engage a second counter engagement element of the second ring filter element. The assembly may be positioned in a filter housing of a filter device provided with housing positioning devices.

Abstract: A filter element has a filter bellows with a first end and an oppositely positioned second end. A first end plate open toward the interior is arranged at the first end and a second end plate at the second end. A circumferential seal contour at the first end plate rises in longitudinal direction away from the first end plate. The filter bellows has at least one notch at an outer and/or inner circumference. The circumferential seal contour has at least one locally limited protrusion or recess in radial direction arranged such that a circumferential position of the protrusion or recess corresponds to a circumferential position of the notch of the filter bellows. A filter device includes the filter element arranged in a receiving space of a filter housing so that the filter element separates a raw side at a fluid inlet from a clean side at a fluid outlet.

Abstract: A filter element for fluid has a folded filter medium body arranged around a longitudinal axis with first folds in a first angular segment and second folds in a second angular segment. The first folds have first outer fold edges lying on an outer cylindrical wall surface and radially opposed first inner fold edges lying on an inner cylindrical wall surface. The second folds have second outer fold edges lying on the outer cylindrical wall surface and radially opposed second inner fold edges lying on an inner conical wall surface. Alternatively, the second inner fold edges lie on the inner cylindrical wall surface and the second outer fold edges lie on an outer conical wall surface outside of the inner cylindrical wall surface. A housing of a matching filter system has a coupling element with a cutout engaging the second angular segment of the filter element.

Abstract: A filter element for filtering a fluid has a filter bellows arranged about the longitudinal axis of the filter element and enclosing an interior of the filter element. A first end disk open toward the interior is arranged at a first end of the filter element. A second closed end disk is arranged at a second end of the filter element. The second end is oppositely positioned to the first end in a direction of the longitudinal axis. The filter bellows has folds with radially outer fold edges positioned on an outer circumferential surface of the filter bellows. The filter bellows is provided with a notch at least at one of the first and second ends. The notch has an axial length in the direction of the longitudinal axis. The axial length is shorter than a length extension of the filter bellows in the direction of the longitudinal axis.

Abstract: A round filter element for filtering a fluid includes a filter medium body with a particle filter medium. The filter medium body surrounds a longitudinal axis and encloses an interior. An end body delimits the filter medium body at an end face of the filter medium body. The end body is an open end plate with a through opening in fluid communication with the interior. A sorption element is arranged in the through opening and connected directly or indirectly to the filter medium body or the end plate. The sorption element is flowed through by the fluid serially relative to the filter medium body in the direction of the longitudinal axis. The sorption element is sealed relative to the through opening. A filter system is provided with the filter element arranged in a filter housing between a fluid inlet and a fluid outlet.

Abstract: A filter element has first and second filter medium bodies, wherein one of the first and second filter medium bodies is arranged inside of the other one of the first and second filter medium bodies, and wherein the filter medium bodies are flowed through sequentially. An end plate is arranged at an end face of the filter element. At least the second filter medium body has a folded filter medium with end face edges at the end face. A side band seals the end face edges of the folded filter medium of the second filter medium body at the end face. The side band is embedded at least partially in the end plate. The filter element may be a cathode air filter of a fuel cell with an anode, a cathode, and electrolyte between the anode and the cathode, and the filter element configured to guide air to the cathode.

Abstract: A ring filter element for air filtration has a filter medium body enclosing an interior. An open end disc and a closed end disc delimit seal-tightly the filter medium body axially. The filter medium body has a folded bellows and an inner wall surface provided with a fold expansion. The open end disc has a cutout aligned with the fold expansion. A filter device has a filter housing with fluid inlet and fluid outlet. A ring filter element arrangement arranged in the filter housing separates fluid inlet from fluid outlet. The ring filter element arrangement has a ring filter element. A positioning device has an engagement element which extends radially outwardly and engages a counter engagement element of the ring filter element which is at least partially formed by the fold expansion at the inner wall surface of the filter medium body of the ring filter element.

Abstract: A secondary element for a filter system has first and second ends oppositely positioned to each other in longitudinal direction. The first end is closed by a closed end disk. The closed end disk has a first connection device for interacting with a complementary second connection device of a central tube of the filter system and for fixing the secondary element on the central tube. The first connection device has lock elements with radially inwardly oriented lock hooks distributed circumferentially on the closed end disk. A filter medium surrounds the lock elements. The lock elements include two directly neighboring lock elements having a distance relative to each other along the circumference of the closed end disk that is larger than a circumferential measurement of a radially outwardly oriented deflection element arranged at a collar of the central tube. A filter system with such a secondary element is provided.

Abstract: A filter element for fluid has a filter medium body with a flow-through medium arranged transversely to a fluid flow direction. A region of the flow-through medium between an inlet surface and an outlet surface of the filter medium body is filled with adsorption medium in intermediate spaces of the flow-through medium. A fluid-permeable cover medium covers the region at a peripheral rim of the inlet surface and/or the outlet surface. A filter system has a filter housing having an inlet and an outlet for fluid. The filter element is exchangeably arranged in the filter housing between a raw-side and a clean-side. A method for producing the filter element includes filling adsorption medium into intermediate spaces of the flow-through medium between an inlet surface and an outlet surface. The region is covered with a fluid-permeable cover medium at a peripheral rim of the inlet surface and/or the outlet surface.

Abstract: A filter element for filtering a fluid has two or more axially extending filter medium bodies arranged to be sequentially flowed through radially and including a first and a second filter medium body. The first filter medium body has an outer diameter smaller than an inner diameter of the second filter medium body, is arranged radially inside the second filter medium body, and has a section projecting axially away from the second filter medium body. A casing is arranged at an outer wall surface of the projecting section and extends at least partially circumferentially around the outer wall surface. The casing fluid-impermeably closes at least temporarily the outer wall surface. The first filter medium body is a particle filter and the second filter medium body is an adsorption filter, or vice versa. A filter system is provided with such a filter element for filtering a fluid.

Abstract: A filter element for filtering a fluid has a support pipe and a filter bellows arranged about a longitudinal axis on the support pipe. The filter bellows has folds with radially outer fold edges. The filter bellows has a first axial end and a second oppositely positioned axial end. The filter bellows has a notch at least at one of the first and second axial ends. An axial length of the notch in longitudinal direction is shorter than a longitudinal extension of the filter bellows. The support pipe has a support structure at the axial end with the notch and has at least two wings. The support structure is oriented radially away from the support pipe and is integrated into the end disk at both sides of the notch. A filter system with such a filter element arranged in a housing is provided.

Abstract: A gas filter system has an outer filter element with a first end plate, a second end plate, and a first filter medium arranged between the first and the second end plates. An inner filter element with a third end plate, a fourth end plate, and a second filter medium arranged between the third and the fourth end plates is provided. The first end plate and the third end plate each have an opening. The first end plate surrounds the third end plate. The first end plate has a first seal protrusion protruding in an axial direction of the gas filter system. The third end plate has a second seal protrusion protruding in the axial direction of the gas filter system. For sealing the third end plate and the first end plate relative to each other, the first seal protrusion and the second seal protrusion engage each other.

Abstract: A filter element for filtering a fluid has a support pipe and a filter bellows arranged about a longitudinal axis on the support pipe. The filter bellows has folds with radially outer fold edges. The filter bellows has a first axial end and a second oppositely positioned axial end. The filter bellows has a notch at least at one of the first and second axial ends. An axial length of the notch in longitudinal direction is shorter than a longitudinal extension of the filter bellows. The support pipe has a support structure at the axial end with the notch and has at least two wings. The support structure is oriented radially away from the support pipe and is integrated into the end disk at both sides of the notch. A filter system with such a filter element arranged in a housing is provided.

Abstract: A gas filter system including a housing, a first filter element having a first filter medium and a second filter element having a second filter medium, the first and second filter elements being arranged inside the housing and the first filter medium and the second filter medium surrounding a common longitudinal axis, wherein a flexible sealing lip protrudes in the axial direction from the first filter medium, wherein the housing has a first sealing surface for sealing abutment against the sealing lip, wherein a rigid sealing rib protrudes from the second filter element, the sealing rib having a second sealing surface for sealing abutment against the sealing lip, wherein the sealing lip is compressed between the first sealing surface and the second sealing surface, and wherein the second sealing surface faces radially outwardly.

Abstract: A gas filter system comprising an outer filter element having a first filter medium arranged between a first end cap and a second end cap, and an inner filter element having a second filter medium arranged between a third end cap and a fourth end cap, the first filter medium being arrangeable to surround the inner filter medium, wherein the first, second, third and fourth end caps are open.

Abstract: A gas filter system including an outer filter element having a first filter medium arranged between a first end cap and a second end cap, and an inner filter element having a second filter medium arranged between a third end cap and a fourth end cap, wherein the first filter medium is arrangeable to surround the second filter medium, wherein the first, third and fourth end caps are open, wherein the outer filter element is closed at the second end cap, wherein the outer filter element has an axial protrusion at the second end cap that protrudes into the inner filter element and exhibits a radially outward facing sealing surface, and wherein the fourth end cap of the inner filter element has a second sealing section for sealing abutment against the sealing surface of the protrusion.

Abstract: A gas filter system including a housing with a sealing projection and a housing groove; an outer filter element having a first filter medium with a first end cap and a second end cap; and an inner filter element having a second filter medium with a third end cap and a fourth end cap, wherein the first end cap has a first axial end cap projection and the third end cap has a second axial end cap projection, the end cap projections being arranged in the housing groove; the first and second end cap projections forming a common groove into which the sealing projection protrudes for sealing abutment against the first end cap and the third end cap at the common groove. The use of an outer filter element and/or an inner filter element in the gas filter system.

Abstract: A gas filter system including an outer filter element having a first filter medium arranged between a first end cap and a second end cap, and an inner filter element having a second filter medium arranged between a third end cap and a fourth end cap, wherein the first, second and third end caps are open, the inner filter element is closed at the fourth end cap, the first filter medium is arrangeable to surround the second filter medium, such that the first end cap of the outer filter element surrounds the third end cap of the inner filter element, the first and third end caps are sealed against each other, and such that the second end cap of the outer filter element surrounds the fourth end cap of the inner filter element, and the second and fourth end caps are sealed against each other.

Abstract: A gas filter system including an outer filter element having a first filter medium arranged between a first end cap and a second end cap, and an inner filter element having a second filter medium arranged between a third end cap and a fourth end cap, wherein the first, third and fourth end caps are open, wherein the outer filter element is closed at the second end cap, wherein the first filter medium is arrangeable to surround the second filter medium, such that the outer filter element is sealed against the inner filter element between the second end cap and the fourth end cap.