Gas Filter System
The gas filter system addresses the issue of ineffective seals in existing systems by using concentrically arranged end caps with polyurethane seals and a central tube-protrusion system, ensuring secure and continuous gas flow through the filter elements.
Patent Information
- Application Number
- JP2025516969
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-09-20
- Filing Date
- 2023-06-20
- Publication Date
- 2025-09-19
AI Technical Summary
Existing gas filter systems for large combustion engines and fuel cells lack an effective seal between two filter elements, leading to potential leaks and inefficiencies in gas filtration.
A gas filter system design where the first and third end caps of the outer filter element are sealed radially and axially to the housing, and the second and fourth end caps of the inner filter element are similarly sealed, with soft polyurethane seals and hard plastic end caps to ensure a secure fit, and a central tube and protrusion system for guidance and support.
The system provides a robust seal between filter elements, ensuring continuous gas flow and preventing leaks, even under vibration, thereby enhancing filtration efficiency and reliability.
Smart Images
Figure 2025531324000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a gas filter system comprising an outer filter element having a first filter medium disposed between a first end cap and a second end cap, and an inner filter element having a second filter medium disposed 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 by the fourth end cap, and the first filter medium is positionable to surround the second filter medium. [Background technology]
[0002] Such a filter system is known from DE 10 2018 215 603 A1.
[0003] In some applications, a gas stream must be filtered through two filter elements. Typically, the gas flows through the first filter element, followed by the pre-filtered gas flowing through the second filter element. The filter elements can be located within a common housing. This type of filter system is used, for example, to filter combustion air for large combustion engines such as trucks and construction vehicles. Another application is filtering air for fuel cells.
[0004] German Patent Application Publication No. 102018215603 discloses a gas filter system having a first filter element surrounding a second filter element. At first axial ends, the open end caps of the two filter elements are associated with a clean air outlet. At second axial ends, the first (outer) filter element has an open end cap, and the second (inner) filter element has a closed end cap. The closed end cap of the inner filter element is arranged to close the opening of the end cap of the outer filter element at the second axial end.
[0005] SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas filter system with an improved seal between two filter elements suitable for joint use.
[0006] This is achieved by the use of a gas filter system according to claim 1 and a filter element according to claim 15. Advantageous embodiments are set out in the dependent claims and the description. Summary of the Invention
[0007] According to the present invention, a gas filter system is provided, comprising an outer filter element having a first filter medium disposed between first and second end caps, and an inner filter element having a second filter medium disposed between third and fourth end caps.
[0008] The first, second, and third end caps are open. The first, second, and third end caps typically have a central opening.
[0009] The inner filter element is closed by a fourth end cap, which may be a monolithic closure end cap, or a closure means may be permanently attached to the inner filter element to seal the fourth end cap.
[0010] The first filter medium can be arranged to surround the second filter medium. The filter medium may be hollow cylindrical or conical, preferably having a generally circular or elliptical cross section. The filter mediums each surround a longitudinal axis. In particular, the filter mediums are arranged concentrically about a common longitudinal axis. Directions such as radial and axial refer to the longitudinal axis of the filter system. As a rule, the first and third end caps are associated with the first axial end, and the second and fourth end caps are associated with the second axial end. The end caps axially cover the filter medium and typically have the same geometric shape as the filter medium in cross section, e.g., a circular or ring shape.
[0011] During use of the gas filter system, the gas flow typically first passes through the first filter medium of the outer filter element and then through the second filter medium of the inner filter element.
[0012] According to the present invention, when the outer filter element is placed around the inner filter element for use in a gas filter system, the first end cap of the outer filter element surrounds the third end cap of the second filter element, and the second end cap of the outer filter element surrounds the fourth end cap of the inner filter element. In other words, the first and third end caps are disposed at the same axial height along the longitudinal axis. Similarly, the second and fourth end caps are disposed at the same axial height along the longitudinal axis. In this mounted state, the first and third end caps are preferably sealed to each other in the radial direction, and the second and fourth end caps are preferably sealed to each other in the radial direction. The sealing of the first and third end caps to each other seals the intermediate space between the first and second filter media at the first end. The sealing of the second and fourth end caps to each other seals the intermediate space between the first and second filter media at the second end. Therefore, the gas to be filtered flows continuously through the two filter elements. The fact that the end caps are positioned at the same axial height does not necessarily mean that the filter bellows are of the same height. For example, if the inner filter element is shorter, the third end cap may include an axial extension or collar for abutting against the first end cap of the outer filter element.
[0013] The first end cap of the outer filter element may have a first seal for sealingly abutting, preferably radially, against the housing. Alternatively or additionally, the first seal may provide axial sealing abutment against the housing. The first seal may be integral with the first end cap.
[0014] Generally, the seals described in the context of the present invention are softer than the mating parts they seal. In particular, each seal is made of polyurethane, preferably foamed polyurethane. The respective mating parts may be made of hard plastic.
[0015] The first end cap of the outer filter element may have a second seal for sealingly abutting, preferably radially, against the third end cap of the inner filter element. The second seal may be integral with the first end cap. Preferably, the first end cap with the first and / or second seal is a monolithic foam component. When the first end cap has a (soft) second seal, the third end cap is generally made of a hard material, such as a hard plastic, that can be bonded to the second filter medium.
[0016] Alternatively, the third end cap of the inner filter element may have a second seal for sealingly abutting, preferably radially, against the first end cap of the outer filter element. The second seal may be integral with the third end cap. In this case, the second end cap is preferably a monolithic foam component. Furthermore, the first end cap is generally constructed of a rigid material, such as a hard plastic, that can be bonded to the first filter element.
[0017] The second end cap of the outer filter element may have a third seal for sealingly abutting, preferably radially, against the fourth end cap of the inner filter element. Preferably, the third end cap having the third seal is a monolithic foam component. When the second end cap has a (soft) third seal, the fourth end cap is generally constructed of a hard material, such as a hard plastic, that can be bonded to the second filter medium.
[0018] Alternatively, the fourth end cap of the inner filter element may have a third seal for sealingly abutting, preferably radially, against the second end cap of the outer filter element. The third seal may be integral with the fourth end cap. In this case, the fourth end cap is preferably a monolithic foam component. Furthermore, the second end cap is generally constructed of a hard material, such as a hard plastic, that can be bonded to the first filter medium.
[0019] The end caps having at least one seal may be made of polyurethane, particularly foamed polyurethane. The end caps to which the seal abuts may be made of hard plastic. The plastic end caps may be glued to the respective filter media.
[0020] The second end cap may have at least one support leg for axially supporting the outer filter element relative to the housing, and the support leg may be integrally formed with the second end cap.
[0021] Preferably, the gas filter system further includes a housing in which the inner and outer filter elements can be disposed. In the installed state, the filter elements are disposed within the housing. Typically, the housing includes a first housing portion associated with the first end and a second housing portion associated with the second end. The inlet may be formed in either the first or second housing portion. The outlet is preferably formed in the first housing portion. The outlet may be in fluid communication with the clean side of the inner filter element.
[0022] The inner filter element has an axial protrusion at the fourth end cap that protrudes into the inner hollow space of the inner filter element. Preferably, the protrusion is integrally formed with the fourth end cap. Alternatively, the protrusion may constitute a closure means for the fourth end cap.
[0023] The housing may have a central tube that extends into the inner filter element at the third end cap when the filter system is installed, the central tube providing a guide for the inner filter element and supporting the second filter medium.
[0024] The central tube can be held in an axial collar of the housing, which is advantageous in manufacturing the filter housing, and a snap fit may be provided between the collar and the central tube.
[0025] Preferably, the protrusion and the central tube overlap each other in the axial direction, which allows mutual guidance and support between the central tube and the inner filter element, which also facilitates installation of the filter system. In particular, the protrusion may be engaged with the central tube. In other words, the central tube may surround the protrusion radially outward.
[0026] Preferably, the housing has a dome projecting into the protrusion at the fourth end cap, which can provide guidance during installation and, in particular, additional support for the inner filter element during use of the filter system.
[0027] Furthermore, the dome and the central tube may be arranged to overlap each other in the axial direction. This design effectively prevents undesired movement of the filter element during operation. In the event of large vibrations, the central tube can contact the dome via a protrusion disposed between the central tube and the dome.
[0028] When the first and / or second filter elements have a rotationally symmetrical shape, it may be advantageous to add features that allow them to be installed in a predetermined position. The protrusion, the central tube, and preferably the dome may have corresponding protrusions or recesses in the radial direction. This allows the inner filter element, and preferably the cover, to be mounted in a predetermined rotational position. Similarly, the second and fourth end caps may have protrusions or recesses to define the relative positions of the inner and outer filter elements in the circumferential direction. Additionally or alternatively, the second end cap and the inner wall of the housing may have corresponding protrusions or recesses.
[0029] The first or second filter medium, especially the second filter medium of the inner filter element, may have gas adsorption properties and preferably comprises activated carbon. Typical harmful gases include SO2, NO X , NH3.
[0030] The first or second filter medium, particularly the first filter medium of the outer filter element, may be composed of cellulose.
[0031] The first and / or second filter media may be pleated.
[0032] The present invention also relates to the use of the outer filter element and / or the inner filter element in a gas filter system according to the invention, as described above, which can be used for cathode air filtration in fuel cells of electric vehicles.
[0033] Other advantages and features of the present invention will be apparent from the following description of embodiments of the invention, with reference to the drawings showing important details, and from the claims. The individual features as described above or below may be implemented individually or in any useful combination in variants of the invention. [Brief explanation of the drawings]
[0034] [Figure 1] 1 is a schematic cross-sectional view of a gas filter system including an outer filter element, an inner filter element, and a housing according to the present invention. [Figure 2] 2 is a schematic cross-sectional view of an outer filter element of the gas filter system of FIG. 1. [Figure 3] 2 is a schematic cross-sectional view of an inner filter element of the gas filter system of FIG. 1. [Figure 4] FIG. 2 is an enlarged view of a first end of the filter system of FIG. 1. [Figure 5] FIG. 2 is an enlarged view of a second end of the filter system of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION
[0035] 1 illustrates a gas filter system 10. The filter system 10 includes a housing 12. The housing has a first housing portion 14 and a second housing portion 16 that are attachable to one another. An inlet 18 allows gas to enter the housing 12. Here, the inlet is formed in the first housing portion 14. A filtered gas outlet 19 is also formed in the first housing portion 14. The housing portions 14, 16 may be made of metal and / or rigid plastic.
[0036] The filter system 10 further includes an outer filter element 20 (see also FIG. 2). The outer filter element 20 has a first filter medium 22. The first filter medium 22 is housed between a first end cap 24 and a second end cap 26. The first filter medium 22 circumferentially surrounds a longitudinal axis 28. The first filter medium 22 may be constructed from pleated cellulose paper.
[0037] The filter system 10 further includes an inner filter element 30 (see also FIG. 3). The inner filter element 30 has a second filter medium 32. The second filter medium 32 is housed between a third end cap 34 and a fourth end cap 36. The second filter medium 32 also circumferentially surrounds the longitudinal axis 28. The second filter medium 32 may be pleated and may include activated carbon for gas adsorption properties.
[0038] The inner filter element 30 is disposed inside the outer filter element 20. Both filter elements 20, 30 are disposed within the housing 12, where the first and second filter media 22, 32 are concentric with each other and with respect to the longitudinal axis 28.
[0039] At the first end of the filter system 10, a first end cap 24 is positioned to surround a third end cap 34 (see also FIG. 4). The first end cap 24 and the third end cap 34 each have a central opening (see FIGS. 2 and 3, respectively). The outlet 19 is in fluid communication with the clean side 40 within the inner filter element 30 (see FIG. 1).
[0040] The first end cap 24 of the outer filter element 20 is sealed axially and / or radially to the housing 12. A first seal portion 42 protrudes axially from the first end cap 24. The first seal portion 42 abuts the first housing portion 14 in the axial and radial directions. The first housing portion 14 has a circumferential rib 44 against which the first seal portion 42 of the first end cap 24 abuts in the radial direction.
[0041] The first end cap 24 and the third end cap 34 are sealed to one another. In the illustrated embodiment, a radial seal is established. The first end cap 24 has a second seal 46. The second seal 46 sealingly abuts the third end cap 34 in the radial direction.
[0042] In the illustrated embodiment, the first end cap 24, including the first seal 42 and the second seal 46, is integrally formed from foamed polyurethane. In other words, the first end cap 24, including the seals 42, 46, is a monolithic component. The third end cap 34 is constructed from a hard plastic and is bonded to the second filter media 32.
[0043] The central tube 48 of the housing 12 is held in an axial collar 50 (see FIGS. 1 and 4). The collar 50 protrudes axially into the housing 12 at the outlet 19. The central tube 48 extends through an opening in the third end cap 34 toward the fourth end cap 36. The central tube 48 may be constructed of a hard plastic.
[0044] At the second end of the filter system 10, the second end cap 26 is positioned to surround the fourth end cap 36 (see also FIG. 5). The second end cap 26 has a central opening (see also FIG. 2). The fourth end cap 36 is closed (see also FIG. 3). In the illustrated embodiment, the fourth end cap 36 is a monolithic, closed end cap. The fourth end cap 36 may be constructed from a rigid plastic and is preferably bonded to the second filter media 32.
[0045] The second end cap 26 and the fourth end cap 36 are sealed to one another. In the illustrated embodiment, a radial seal is established. The second end cap 26 has a third seal 52. The third seal 52 sealingly abuts the fourth end cap 36 in the radial direction. The second end cap 26 and the third seal 52 can be integrally formed from foamed polyurethane. In other words, the second end cap 26 and the seal 52 are a monolithic part.
[0046] In its central region (the radial region within the second filter medium 32), the fourth end cap 36 forms a protrusion 54 (see FIGS. 1, 3, and 5) that extends axially into the inner filter element 30 toward the third end cap 34.
[0047] The central tube 48 of the housing 12 and the protrusions 54 of the inner filter element 30 overlap one another along the longitudinal axis 28. The protrusions 54 may be tapered so that they extend into the central tube 48.
[0048] The housing 12 may have a dome 56. Here, the dome 56 is formed on the second housing portion 16, which may be, for example, a removable cover. The dome 56 extends toward the inside of the inner filter element 30. In particular, the dome 56 extends into the protrusion 54 of the inner filter element 30. More specifically, the protrusion 54 protrudes into the central tube 48, such that the dome 56, the protrusion 54, and the central tube 48 overlap one another along the longitudinal axis 28. [Explanation of symbols]
[0049] Gas filter systems 10 Housing 12 First housing part 14 Second housing part 16 Inlet 18 Outlet 19 Outer filter element 20 First filter element 22 First End Cap 24 Second End Cap 26 Longitudinal axis 28 Inner filter element 30 Second filter element 32 Third End Cap 34 4th end cap 36 Clean side 40 First seal portion 42 Rib 44 Second seal part 46 central tube 48 Color 50 Third seal part 52 Projection 54 Dome 56
Claims
1. A gas filter system (10) comprising: an outer filter element (20) having a first filter medium (22) disposed between a first end cap (24) and a second end cap (26); an inner filter element (30) having a second filter medium (32) disposed between a third end cap (34) and a fourth end cap (36); the first, second, and third end caps (24, 26, 34) are open; The inner filter element (30) is closed by the fourth end cap (36); the first filter medium (22) is positionable to surround the second filter medium (32) such that the first end cap (24) of the outer filter element (20) surrounds the third end cap (34) of the inner filter element (30), the first and third end caps (24, 34) are sealed to one another, the second end cap (26) of the outer filter element (20) surrounds the fourth end cap (34) of the inner filter element (30), and the second and fourth end caps (26, 36) are sealed to one another; The gas filter system (10) includes an inner filter element (30) having an axial protrusion (54) on the fourth end cap (36), the protrusion (54) protruding into an inner hollow space of the inner filter element (30).
2. The gas filter system (10) of claim 1, wherein the fourth end cap (34) is a monolithic closed end cap.
3. 3. The gas filter system (10) of claim 1 or 2, wherein the first end cap (24) of the outer filter element (20) has a first seal portion (42) for sealingly abutting, preferably radially, against the housing (12).
4. 4. The gas filter system of claim 1, wherein the first end cap of the outer filter element has a second seal for sealingly abutting, preferably radially, against the third end cap of the inner filter element.
5. The gas filter system (10) of claims 3 and 4, wherein the first end cap (24) is a monolithic foam component.
6. 6. The gas filter system of claim 1, wherein the second end cap of the outer filter element has a third seal for sealingly abutting, preferably radially, against the fourth end cap of the inner filter element.
7. The gas filter system (10) of any one of claims 1 to 6, further comprising a housing (12) in which the outer and inner filter elements (20, 30) are positionable.
8. 8. The gas filter system (10) of claim 7, wherein the housing (12) has a center tube (48) that extends into the inner filter element (30) at the third end cap (34).
9. The gas filter system (10) of claim 8, wherein the protrusion (54) and the central tube (48) axially overlap one another.
10. The gas filter system (10) of any one of claims 7 to 9, wherein the housing (12) has a dome (56) that protrudes into the protrusion (54) at the fourth end cap (36).
11. 11. The gas filter system (10) of claim 8 or 9 and claim 10, wherein the dome (56) and the central tube (48) overlap each other in the axial direction.
12. The gas filter system (10) according to any one of claims 1 to 11, wherein the first or second filter medium (22, 32), in particular the second filter medium (32) of the inner filter element (30), has gas adsorption properties and preferably comprises activated carbon.
13. 13. The gas filter system (10) according to any one of claims 1 to 12, wherein the first or second filter medium (22, 32), in particular the first filter medium (22) of the outer filter element (20), is made of cellulose.
14. Use of an outer filter element (20) and / or an inner filter element (30) in a gas filter system (10) according to any one of claims 1 to 13.