Filter device, especially air filter for an internal combustion engine

1. An air filter element for exchangeable installation in a filter housing in which the filter element is flown through by a fluid to be filtered, the filter element comprising:

a fluid flow intake side;

a fluid outflow side;

wherein said outflow side is spaced apart axially from said inflow side;

at least two radially nested filter bellows;

wherein at least one filter bellows of said at least two filter bellows is to be flown through in a radial direction;

wherein an annular flow space is formed radially between said nested filter bellows, said annular flow space in fluid flow communication with an end face of the filter element;

wherein each filter bellows is embodied as a star-shaped filter with filter folds arranged in a star shape;

a sealing ring arranged on at least one end face of said filter element, said sealing ring operable for engaging an interior of said filter housing to separate an unfiltered side from a filtered side of said filter element;

wherein a cover disk closes over an interior of a radially inwardly one of said nested filter bellows, said cover disk extending radially across said interior preventing fluid in the interior from flowing axially by said cover disk;

wherein front edges of filter media folds of a first one of said at least two filter bellows at one end face are completely covered by a cover ring;

wherein front edges of filter media folds of said at least two filter bellows are completely covered at an opposite end face with a second cover ring preventing axial flow from passing through filter media fold front edges at said opposite end face;

wherein a portion of said filter folds of one of said at least two filter bellows is immediately contacting against and adhesively connected and tacked to immediately neighboring filter folds of a different one of said at least two filter bellows at an axial end face of said filter bellows.

2. An air filter element for exchangeable installation in a filter housing in which the filter element is flown through by a fluid to be filtered, the filter element comprising:

a fluid flow intake side;

a fluid outflow side;

wherein said outflow side is spaced apart axially from said inflow side;

at least two radially nested filter bellows;

wherein at least one filter bellows of said at least two filter bellows is to be flown through in a radial direction;

wherein an annular flow space is formed radially between said nested filter bellows, said annular flow space in fluid flow communication with an end face of the filter element;

wherein each filter bellows is embodied as a star-shaped filter with filter folds arranged in a star shape;

a sealing ring arranged on at least one end face of said filter element, said sealing ring operable for engaging an interior of said filter housing to separate an unfiltered side from a filtered side of said filter element;

wherein a cover disk closes over an interior of a radially inwardly one of said nested filter bellows, said cover disk extending radially across said interior preventing fluid in the interior from flowing axially by said cover disk;

wherein front edges of filter media folds of a first one of said at least two filter bellows at one end face are completely covered by a cover ring;

wherein front edges of filter media folds of said at least two filter bellows are completely covered at an opposite end face with a second cover ring preventing axial flow from passing through filter media fold front edges at said opposite end face;

wherein front edges of the filter folds of at least one of said filter bellows are tacked closed at at least one of said intake side or said outflow side of said filter element, ensuring fluid flow of said filter bellows must flow radially through said tacked filter bellows in radial direction and not through said tacked front edges.

3. The filter element according to claim 2 , wherein

a free flow passage is formed between two tacked filter folds each at the end face of a filter bellows.

4. The filter element according to claim 2 , wherein

said tacked filter folds are glued together.

5. Filter element according to claim 2 , wherein

the filter bellows are embodied as individual bellows.

6. The filter element according to claim 2 , wherein

a radially inwardly positioned one of said at least two filter bellows is conically embodied,

wherein a radially outwardly positioned one of said at least two filter bellows is cylindrically embodied,

wherein said flow space between said nested filter bellows has a cross-section that increases towards said outflow side of said filter element,

wherein said flow space between said filter bellows is framed by a support frame, said support frame cross-section increasing towards said outflow side of flow space between said nested filter bellows such that said support frame on opposing sides supports respective ones of said radially nested filter bellows in position relative to one another and frames the flow space.

7. The filter element according to claim 2 , wherein

said flow space between said nested filter bellows has a cross-section that increases towards said outflow side of said filter element.

8. The filter element according to claim 2 , wherein

said flow space between the filter bellows is framed by a support frame such that said support frame on opposing sides supports respective ones of said radially nested filter bellows in position relative to one another and frames said flow space.

9. The filter element according to one of the claim 7 , wherein

said flow space forms a clean chamber and is closed off axially relative to said intake side

wherein said filter bellows that radially delimit said flow space are each are flown through radially in said direction of the flow space.

10. The filter element according to claim 9 , wherein

at least one of said filter bellows at one end face of said filter element is open for axial flow into said filter media folds.

11. The filter element according to claim 2 , wherein

said annular flow space formed between said radially spaced nested filter bellows is open for flow at either said intake side or said outflow side of the filter element and is closed off to flow at the opposing flow side of the filter element,

wherein said annular flow space is open only to one of said flow sides of the filter element.

12. The filter element according to claim 11 , wherein

said second cover ring is arranged at said closed off flow side connecting adjacent axial end faces of said nested filter bellows.