Filter System Comprising a Filter Element and Secondary Element for Closing a Central Tube

Abstract

A filter system for filtering fluid has a filter housing with inlet socket and outlet socket for fluid. A central tube with radially open region over a portion of its axial length is arranged in the filter housing in flow communication with the outlet socket in an operating state. Within the central tube, a secondary element is arranged slidably between first and second operating positions. A filter element, separating a raw fluid side from a clean fluid side, has a filter bellows with a first end plate at a first end face and a second end plate at a second end face. The end plates have central openings for receiving the central tube in the filter element interior. In the first operating position, the secondary element opens a fluid path through the radially open region of the central tube and closes the fluid path in the second operating position.

Claims

1. A filter system for filtering a fluid, the filter system comprising: a filter housing comprising a housing top part and a housing bottom part, wherein the housing top part and the housing bottom part extend along a housing axis of the filter housing; an inlet socket, arranged at the filter housing, configured to supply a fluid to be filtered; an outlet socket, arranged at the housing bottom part, configured to discharge the fluid after filtration; a central tube arranged concentrically to the housing axis in the filter housing and connected in flow communication with the outlet socket in at least one operating state, wherein the central tube, over at least a portion of an axial length of the central tube, comprises a radially open region; a secondary element arranged within the central tube so as to be slidable along the housing axis between at least a first operating position and a second operating position, wherein the secondary element is tubular; a filter element configured to be arranged in the filter housing and to separate fluid-tightly a raw fluid side from a clean fluid side, wherein the filter element comprises a filter bellows arranged about a longitudinal axis of the filter element, wherein the filter bellows comprises a first end plate at a first end face of the filter bellows and further comprises a second end plate at a second end face of the filter bellows, wherein the first and second end plates each comprise a central opening configured to receive the central tube in an interior of the filter element; wherein the secondary element in the first operating position opens a fluid path through the radially open region of the central tube and in the second operating position closes the fluid path through the radially open region of the central tube.

2. The filters system according to claim 1, wherein the outlet socket is arranged concentrically relative to the housing axis.

3. The filter system according to claim 1, wherein the secondary element comprises an axial length that is at least as long as said portion of the axial length of the central tube.

4. The filter system according to claim 1, wherein the secondary element comprises a radial outer side comprising sealing elements configured to seal against the central tube, wherein the sealing elements are selected from sealing surfaces; seals; or sealing surfaces and seals.

5. The filter system according to claim 4, wherein the sealing elements are arranged at opposite ends of the secondary element.

6. The filter system according to claim 1, wherein the filter element comprises a first seal configured to seal the raw fluid side relative to the filter housing and further comprises a second seal configured to seal against the central tube.

7. The filter system according to claim 6, wherein at least one of the first and second seals is connected to one of the first and second end plates.

8. The filter system according to claim 6, wherein the first seal is arranged at the first end plate and is embodied as an axial seal.

9. The filter system according to claim 6, wherein the second seal is arranged at the second end plate and is embodied as a radial seal.

10. The filter system according to claim 6, wherein the first seal is arranged at the first end plate and is embodied as an axial seal and wherein the second seal is arranged at the second end plate and is embodied as a radial seal.

11. The filter system according to claim 6, wherein the secondary element is closed at an end facing away from the outlet socket.

12. The filter system according to claim 1, wherein the secondary element comprises a wall, wherein the wall is comprised at least in sections thereof of a filter medium.

13. The filter system according to claim 1, wherein the filter element is a round filter.

14. The filter system according to claim 13, wherein the round filter comprises a hollow cylindrical shape.

15. The filter system according to claim 1, wherein, when closing the filter housing, the central tube is configured to be closed by the housing top part at an end face plane of the central tube facing away from the outlet socket.

16. The filter system according to claim 15, wherein the housing top part, when the filter housing is closed, dips into the end face plane of the central tube.

17. A method for exchanging a filter element in a filter system according to claim 1, comprising: removing the housing top part from the housing bottom part of the filter housing; displacing the secondary element along the housing axis and closing the fluid path through the radially open region of the central tube with the secondary element; removing the filter element from the central tube along the housing axis.

18. A secondary element for a filter system according to claim 1, the secondary element comprising a wall comprising at least in sections thereof a filter medium, wherein the secondary element is tubular and is configured to be arranged within a central tube so as to be slidable along a housing axis of a filter housing of the filter system between at least a first operating position and a second operating position.

19. A filter element for a filter system according to claim 1, the filter element comprising a filter bellows arranged about a longitudinal axis of the filter element, wherein the filter bellows comprises a first end plate at a first end face of the filter bellows and further comprises a second end plate at a second end face of the filter bellows, wherein the first and second end plates have openings configured to receive a central tube of a filter housing in an interior of the filter element.

20. The filter element according to claim 19, wherein the first end plate comprises a first seal and wherein the second end plate comprises a second seal, wherein the first seal is configured to seal a raw fluid side relative to a filter housing of the filter system, and wherein the second seal is configured to seal against the central tube of the filter housing.

21. The filter element according to claim 19, wherein the first seal at the first end plate is an axial seal and/or a radial seal, and wherein the second seal at the second end plate as a radial seal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further advantages result from the following drawing description. In the drawings, embodiments of the invention are illustrated. The drawings, description, and the claims contain numerous features in combination. A person of skill in the art will consider the features expediently also individually and combine them to other expedient combinations.

[0035] FIG. 1 shows a perspective longitudinal section of a filter system according to an embodiment of the invention with a secondary element in a first operating position and open filter housing.

[0036] FIG. 2 shows a perspective longitudinal section of the filter system in FIG. 1 with the secondary element in a second operating position.

[0037] FIG. 3 shows a perspective longitudinal section of the filter system in FIG. 1 with the secondary element in a second operating position during removal of the filter element.

[0038] FIG. 4 shows a perspective longitudinal section of the filter system in FIG. 1 with the secondary element in the first operating position and closed filter housing.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0039] In the Figures, same or same-type components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting.

[0040] FIG. 1 represents a perspective longitudinal section of a filter system 100 according to an embodiment of the invention with a secondary element 40 in a first operating position P1 and an open filter housing 110.

[0041] The filter system 100 comprises a filter housing 110 of a housing top part 114, which has been omitted in FIG. 1, and a housing bottom part 112, which extends along a housing axis M, as well as an inlet socket (not illustrated) arranged at the filter housing 110 for supply of a fluid to be filtered, and an outlet socket 108, which is arranged at the housing bottom part 112 concentrically to the housing axis M, for discharge of the filtered fluid. A central tube 30, which is concentrically arranged to the housing axis M and which is connected in flow communication to the outlet socket 108 in at least one operating state and which comprises a radially open region 32 at least over a portion 36 of its axial length, is connected to the housing bottom part 112. The radially open region is facing the outlet socket 108 and, as illustrated, is preferably embodied in direct continuation of the outlet socket in particular non-detachably or monolithically with the housing bottom part 112 and is stiffened or formed by axial stays 34 of the central tube 30. A secondary element 40, which is of a tubular configuration, is arranged so as to be slidable along the housing axis M within the central tube 30 between at least two operating positions P1, P2. The radially closed region of the central tube 30 is embodied preferably of a closed tubular configuration, adjoins the radially open region, and is facing away from the outlet socket 108. As illustrated, the end of the central tube 30 or of the radially closed region which is facing away from the outlet socket 108 is preferably embodied open in order to be able to service the secondary element 40.

[0042] Furthermore, a filter element 10 that fluid-tightly separates a raw fluid side 50 from a clean fluid side 52 is arranged in the filter housing 110 wherein the filter element 10 comprises a filter bellows 12, which is arranged about the longitudinal axis L of the filter element, with a first end plate 14 at a first end face 26 and a second end plate 16 at a second end face 28. The filter element 10 is embodied as a hollow cylindrical round filter. The end plates 14, 16 of the filter element 10 comprise central openings 15, 17 for receiving the central tube 30 in the interior 22 of the filter element 10. The filter bellows 12 is flowed through by air from the exterior to the interior in radial direction, which is illustrated by the fluid path 56. The filtered air is discharged through the outlet socket 108 from the filter housing 110.

[0043] The filter element 10 comprises seals 18, 20, one of which is provided for sealing the raw fluid side 50 relative to the filter housing 110 and one of which is provided for sealing against the central tube 30. The seals 18, 20 are connected to the end plates 14, 16 and can be produced, for example, together with the end plates 14, 16 by a plastics foaming process. The seal 18 at the first end plate 14 is embodied for sealing relative to the filter housing 110 as a radial seal, as is preferred. The seal 20 at the second end plate 16 is embodied for sealing against the central tube 30 as a radial seal.

[0044] The secondary element 40 in the first operating position P1, which is illustrated in FIG. 1, opens the fluid path 56 through the open region 32 of the central tube 30 and closes in the second operating position P2 the fluid path 56 through the open region 32. The secondary element 40 comprises for this purpose an axial length that is at least as long as the portion 36 of the axial length of the radial open region 32 of the central tube 30. Moreover, the secondary element 40 comprises at its radial outer side sealing elements in the form of sealing surfaces and/or seals 46, 48 for sealing against the central tube 30 or the housing bottom part 112. The sealing surfaces and/or seals 46, 48 are arranged at opposite ends 60, 62 of the secondary element 40. The secondary element 40 is closed at an end 62 which is facing away from the outlet socket 108 by a cover so that the central tube 30, in which the secondary element 40 is seal-tightly slidably arranged with the seals 46, 48, is sealed by the secondary element 40 relative to the raw fluid side 50. The wall 42 of the secondary element 40 comprises at least in sections thereof a filter medium so that air can pass through the secondary element 40, when it is pushed in front of the open region 32 of the central tube 30, in radial direction from the exterior through the secondary element 40 and the air is filtered thereby.

[0045] FIG. 2 shows a perspective longitudinal section of the filter system 100 in FIG. 1 with the secondary element 40 in a second operating position P2. In this operating position P2, the secondary element 40 is pushed in front of the open region 32 of the central tube 30, i.e., into a position downstream, in particular immediately downstream, of the open region 32 of the central tube 30 and covers it completely. The secondary element 40 seals with its seals 46, 48 against the inner side of the central tube 30 and with its cover 44 relative to the raw fluid side 50 so that flowing air can pass to the clean fluid side 52 only through the wall 42 of the secondary element 40, which is embodied as a filter medium, and is thereby also filtered.

[0046] In FIG. 3, a perspective longitudinal section of the filter system 100 in FIG. 1 is illustrated with the secondary element 40 in the second operating position P2 during removal of the filter element 10.

[0047] For exchange of the filter element 10, first the housing top part 114 is removed from the housing bottom part 112 of the filter housing 110. Then, the secondary element 40 is moved along the housing axis M such that the secondary element 40 closes the fluid path 56 through the open region 32 of the central tube 30 of the filter housing 110, as is illustrated in FIG. 3 in the operating position P2. Thus, the clean fluid side 52 is effectively separated by the secondary element 40 from the raw fluid side 50 so that only air that has been filter by the secondary element 40 can reach the clean fluid side 52. Accordingly, the filter element 10 can be removed from the central tube 30 along the housing axis M in upward direction.

[0048] When inserting a new filter element 10, the reverse sequence is observed. First, the filter element 10 is pushed onto the central tube 30 until it contacts the bottom in the housing bottom part 112 and is seal-tightly arranged against the housing bottom part 112 and the central tube 30. Subsequently, the secondary element 40 can be pushed into the first operating position P1 in upward direction and the open region 32 can thus be opened as a bypass for the fluid path 56. Finally, the housing top part 114 is attached and the filter system 100 is again in the operation-ready state.

[0049] FIG. 4 shows a perspective longitudinal section of the filter system 100 in FIG. 1 with the secondary element 40 in the first operating position P1 and closed filter housing 110 in which the housing top part 114 is attached to the housing bottom part 112. In this context, the housing top part 114 dips, with the filter housing 110 closed, into the end face plane 24 of the central tube 30 with a central depression 116 and can serve as a stop for the secondary element 40. The central tube 30 is closed at the end face plane 24 facing away from the outlet socket 108 by the secondary element 40. Since the housing top part 114 dips into the end face plane 24 of the central tube 30 with a central depression 116, the central tube 30 can be additionally secured at this end by means of the placed-on depression 116 of the housing top part 114 and stiffened with regard to vibrations or shocks. In this context, the depression 116 of the housing top part 114 engages centrally through the end plate 16 of the filter element 10, which is enabled by the opening 17 of the end plate 16.