Support tube for a filter element, filter element, filter system and method for producing a filter element

Abstract

Support tube (14) for a filter element (10), comprising a flow-through body (16) which is designed as a self-supporting structure (25), and wherein the body (16) has three-dimensionally interconnected, connected channels (18), characterized in that the body (16) is solid and the channels (18) are designed so that a fluid can flow through them from a flat outer side (28) of the body (16) to at least one end face (22).

Description

Technical area

[0001] The invention relates to a support tube for a filter element for installation in a filter system for filtering a fluid, in particular as a liquid fluid filter or air filter of an internal combustion engine, a filter element with such a support tube and a filter system with such a filter element as well as a method for producing such a filter element. State of the art

[0002] Given the ever-increasing space requirements of vehicle manufacturers in the wake of downsizing internal combustion engines, as well as the need for extremely compact range-extending internal combustion engines, it can be assumed that there will be demands for liquid filters or air filters to be designed in a wide variety of shapes. Liquid filters, in particular, are usually designed with a rotationally symmetrical filter element, with the center tube or support tube being cylindrical or at least concavely symmetrical.

[0003] GB 1 545 057 A discloses a method for producing a support for a fluid filter element, which contains a plurality of particles that are in contact with one another in a vessel shaped like the fluid filter element. The components of a polymer are mixed with a blowing agent to form a foam. Before the foam solidifies, it is injected into the vessel to penetrate the spaces between the particles. The resulting molded body is removed from the vessel after solidification. The particles are dissolved in a solvent that does not dissolve the polymer, thereby obtaining a support for the filter element with a structure that has interstices.

[0004] DE 10 2005 014 360 A1 describes a filter element comprising a star-shaped pleated filter medium, with a fluid-permeable support extending into the space between two adjacent filter pleats on the inner and / or outer circumference. The support contains filter-active substances, thus acting as a filter aid and thus increasing the service life of the filter element.

[0005] From WO 85 / 04 595 A1, a filter consisting of a fluid-permeable, dimensionally stable, porous, foam-shaped molded body is known, wherein the large pores present on the surface of the filter are filled with a filling material so that air-permeable areas of different pore sizes are created. Disclosure of the invention

[0006] An object of the invention is therefore to provide a support tube for a filter element for filtering a fluid, which allows different geometric shapes of a filter element to be represented with little tool effort.

[0007] A further object of the invention is to provide a filter element which allows the use of such a support tube for different geometric shapes of a filter element.

[0008] A further object of the invention is to provide a filter system for accommodating such a filter element.

[0009] A further object of the invention is to provide a method for producing such a filter element.

[0010] The above-mentioned object is achieved according to one aspect of the invention by a support tube for a filter element having the features of claim 1.

[0011] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

[0012] A support tube for a filter element for filtering a fluid is proposed, comprising a body configured as a self-supporting structure. The body has three-dimensionally interconnected, interconnected channels.

[0013] The support tube according to the invention solves the problem of fitting a filter element constructed therewith into a very limited and irregularly shaped installation space, for example around a relatively small range extender internal combustion engine, without unfavorable empty spaces.

[0014] The support tube of a filter element is usually a plastic cage in which a plastic framework provided with openings surrounds a hollow space. The production of this cage requires complex tooling, particularly if shapes deviating from the cylindrical form are to be created. The support tube according to the invention can, for example, be foamed from a suitable material. In this way, a body with an open-pore framework can be formed, which ensures very good pressure stability. The flow resistance can be adjusted by designing the pore sizes and the choice of material, as can the pressure stability, even though the support tube is solid. The body of the support tube itself is permeable to flow and forms the self-supporting structure. The support tube can, for example, be designed in a structure similar to a long bone known from nature, in which a cross-linked framework forms a self-supporting structure.Such a long bone has three-dimensionally interconnected, interconnected channels through which fluid can flow. Furthermore, a cavity is formed inside the long bone through which fluid that has passed through the interconnected framework can flow out.

[0015] The advantages of a support tube designed in this way include low tooling costs and the flexibility to create any desired shape. Furthermore, such a support tube exhibits high pressure stability despite its non-cylindrical shape, as material bridges in the form of webs absorb the pressure of the flowing fluid. The body of the support tube itself is permeable to fluid.

[0016] Such a support tube is advantageously designed as a solid, non-tubular or non-hollow-cylindrical support element. This also allows for the flexible realization of special cross-sectional shapes.

[0017] In a favorable embodiment, such a support tube can be designed in the form of a sponge or as a so-called compressed foam in which webs remain. For example, the material Basotect from BASF can be used, with which the required porosity of a support tube can be produced. The body, as the actual support tube for a filter element, can thus be designed as a self-supporting structure. Due to the porosity, three-dimensionally interconnected, interconnected channels can be formed in the body, through which the fluid to be filtered can advantageously flow.

[0018] According to the invention, the body is designed to be solid. With such a solid design, a three-dimensional body can be easily adapted to a wide variety of installation spaces while still maintaining the necessary stability to stiffen the filter medium and withstand the pressure of the flowing fluid.

[0019] According to an advantageous embodiment, the body can be formed at least partially from a foam. An open-pore foam advantageously fulfills the requirements to provide both the mechanical strength required to form a self-supporting structure as the body of the support tube and, thanks to its open pores, to have three-dimensionally interconnected, connected channels. For this purpose, the foam is injected into a negative mold as a tool for the desired shape of the support tube and, after curing, is demolded appropriately by disassembling a multi-part tool and removing the molded part of the body. Alternatively, it is also conceivable to use a disposable, coherent negative mold as the tool, which can, for example, be dissolved after the foam has cured.

[0020] According to an advantageous embodiment, the body can be formed, at least in part, from a sintered material. Sintered materials can also have the required structure of three-dimensionally interconnected, interconnected channels while simultaneously providing sufficient strength as a self-supporting structure for the body of the support tube. Since the sintered material can, for example, be poured into a mold as a loose material and subsequently sintered by pressure and / or heat, a wide variety of body shapes are possible.

[0021] According to an advantageous embodiment, the body can be formed, at least in part, from a wire mesh. The wire mesh can be adapted to a wide variety of installation spaces and, with appropriate cross-linking, provides the necessary stability for the formation of the self-supporting structure. The spaces between the wires represent advantageous, three-dimensionally interconnected, interconnected channels through which the fluid to be filtered can flow.

[0022] According to an advantageous embodiment, the self-supporting structure, which is made of a sintered material, can be formed from plastic and / or metal and / or ceramic. Suitable sintered materials can be inexpensively produced from these material classes and are conventionally used for a wide variety of applications. For this reason, bodies for support tubes can also be inexpensively manufactured from these materials. Constructed in this way, bodies for support tubes exhibit suitable features such as a self-supporting structure and three-dimensionally interconnected, interconnected channels.

[0023] According to an advantageous embodiment, the body can be formed, at least in part, from an extruded plastic. Plastic extrusion processes can also be used to create suitable open-pore structures that exhibit self-supporting properties with the necessary stability. The open-pore structure also provides three-dimensionally interconnected, interconnected channels that serve as flow paths for the fluid to be filtered.

[0024] According to an advantageous embodiment, the body can be formed, at least in part, from a fibrous structure. It is also conceivable to combine fibers to form a cross-linked structure in order to achieve the required stability. The cavities created by the fibrous structure in the resulting body can also be used to form channels into which the fluid can flow effectively.

[0025] According to an advantageous embodiment, the body can have a skeletal structure with cavities and webs. Such a structure can also be designed as a self-supporting structure, as is often seen in nature. Suitable cavities are formed between the webs, through which the fluid can flow effectively.

[0026] According to an advantageous embodiment, the body can have an amorphous structure. Such an amorphous structure, which does not have a regular lattice structure, can be manufactured in a variety of ways, for example, as a sintered material, and meets the requirements for both the necessary inherent stability and the necessary porosity to allow the filtered fluid to flow away.

[0027] According to an advantageous embodiment, the channels can be designed so that a fluid can flow through them from a flat outer surface of the body to at least one end face. Such a design of the support tube is advantageous if a filter medium is applied to the outer surface of the body, through which the fluid flows. The fluid is filtered and can flow through the interior of the support tube and be guided to an outlet of the filter element and the filter system at one end face.

[0028] According to a further aspect, the invention relates to a filter element with a flow-through filter medium for filtering a fluid with a support tube according to the invention, which comprises a body which is designed as a self-supporting structure with three-dimensionally interconnected, connected channels, wherein the filter medium is arranged flatly on the support tube and the self-supporting structure of the body of the support tube forms part of a fluid path between a raw side and a clean side of the filter medium.

[0029] Since the support tube can be adapted to a wide variety of irregular installation spaces, the filter element constructed with it, with a filter medium applied directly to the support tube, can also be adapted to such installation spaces. The filter element according to the invention can thus be fitted into a very limited and irregularly shaped installation space of an internal combustion engine, for example around a relatively small range extender internal combustion engine, without creating unfavorable empty spaces. The support tube can, for example, be foamed from a suitable material. In this way, an open-pore framework can be formed that ensures very good pressure stability. The flow resistance can be adjusted by designing the pore sizes and the choice of material, as can the pressure stability. This allows a very efficient filter element to be designed and adapted to the installation space.

[0030] According to the invention, at least one end face of the support tube is provided as an outlet for the filtered fluid. If a filter medium through which the fluid flows is applied to the outside of the body, such a design is particularly advantageous. The fluid is filtered and can flow through the interior of the support tube and be conveniently guided to an outlet of the filter element and the filter system at one end face.

[0031] According to a further aspect, the invention relates to a filter system for filtering a fluid, comprising at least one filter element and a filter housing with a first housing part and a second housing part, which enclose the inserted filter element. The filter housing further has at least one inlet for supplying the fluid to be filtered and at least one outlet in a housing wall. Flow can flow through the filter element from a raw side to a clean side. The body of the support tube forms part of a fluid path between the raw side and the clean side.

[0032] Based on the ever-increasing space requirements of vehicle manufacturers in the course of downsizing internal combustion engines, but also due to the need for extremely compact range-extending internal combustion engines, such a filter system can be advantageously adapted to the different installation spaces, both as a liquid filter and as an air filter, thus avoiding the need for unfavorable empty spaces around an internal combustion engine. Liquid filters, in particular, which are usually designed with a rotationally symmetrical filter element, can thus be suitably designed for irregular installation spaces.

[0033] In the embodiment according to the invention, one end face of the support tube is connected to the outlet of the filter housing on the flow side. Such a design is particularly advantageous if a filter medium, through which the fluid flows, is applied to the outside of the body. The fluid is filtered and can flow through the interior of the support tube and be conveniently guided to an outlet of the filter element and the filter system at one end face.

[0034] According to a further aspect, the invention relates to a method for producing a filter element, wherein a support tube is produced by at least one of the following methods: foaming a negative mold with an open-pore foam, extruding a plastic, filling a negative mold with a compressed foam, punching out of a volume, or sintering metal and / or plastic and / or a ceramic material. In this case, a filter medium is applied flatly to the support tube so that at least one outlet for a filtered fluid to flow out of the support tube is formed. The various production methods serve to create a body which is designed as a self-supporting structure and which has three-dimensionally interconnected, connected channels.Using the body as a support tube, filter elements and filter systems with irregular shapes can be designed, which can be fitted into various complex installation spaces around internal combustion engines. The fluid can flow through a filter medium applied to the outside of such a support tube and be filtered. It can then flow through the three-dimensionally interconnected channels on the clean side of the filter element and be guided to an outlet.

[0035] According to an advantageous embodiment, cavities in the body can be formed by dissolving material in a subsequent process step. In this way, for example, particles can be embedded in a foam-like mass, which is then cured. The particles represent a negative form of the desired three-dimensionally interconnected, connected channels. If the particles are then dissolved using a suitable process in a subsequent step, the structure of the foam around the particles remains and forms the self-supporting structure of the body. The channels are now also free and can be flowed through by the fluid. Instead of foam, it is of course also conceivable to use one of the other manufacturing processes mentioned above, such as extrusion of plastic, sintering of plastic, metal or ceramic.

[0036] According to an advantageous embodiment, the filter medium can be applied in a self-contained manner to the surface of the support tube. This advantageously creates a filter element through which a fluid can flow from an outer side. After passing through the filter medium, the fluid can flow out through the three-dimensionally interconnected, interconnected channels on an inner side of the support tube. Short description of the drawings

[0037] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0038] Examples include: Fig. 1 a cross-section through a filter element according to an embodiment of the invention with an irregularly shaped support tube; Fig. 2 an isometric view of the filter element according to the embodiment in Fig. 1; Fig. 3 a cross section through a filter element according to a further embodiment of the invention with a cylindrical support tube; Fig. 4 a cross section through a filter element according to a further embodiment of the invention with a flat support tube; Fig. 5 a cross-section through a support tube according to a further embodiment of the invention, which is bent at an angle; Fig. 6 an isometric representation of a support tube not according to the invention, designed as a hollow cylinder; Fig. 7 a section through spongy tissue of a long bone as an example of a coarse open-cell structure; and Fig. 8 a longitudinal section through a filter system according to an embodiment of the invention. Embodiments of the invention

[0039] In the figures, identical or similar components are designated by the same reference numerals. The figures are merely examples and are not to be construed as limiting.

[0040] Fig. 1 shows a cross section through a filter element 10 according to an embodiment of the invention with an irregularly shaped support tube 14. The filter element 10 has a flow-through filter medium 12 for filtering a fluid, which is applied, for example, glued, to an outer side 28 of a support tube 14. The filter medium 12 is arranged flat on the support tube 14. The support tube 14 comprises a solid body 16, which is designed as a self-supporting structure 25 with three-dimensionally interconnected, connected channels 18. The solid body 16 of the support tube 14 thus forms part of a fluid path 30 between a raw side 52 and a clean side 50 of the filter medium 12. The body 16 in the Fig. The embodiment shown in Figure 1 is solid, but can also have hollow areas. For example, the body 16 can form a wall surrounding a cavity, which enables a favorable weight reduction. The channels 18 are designed so that a fluid can flow through them from the flat outer side 28 of the body 16 via the interior 24 of the support tube 14 to at least one end face 22. At least one end face 22 of the support tube 14 is provided as an outlet 32 for the filtered fluid.

[0041] The body 16 can be made of different materials. It is conceivable that the body 16 is formed, at least in part, from a foam. Alternatively, the body 16 can also be formed, at least in part, from a sintered material, with the self-supporting structure 25 being formed from plastic and / or metal and / or ceramic. It is also possible for the body 16 to be formed, at least in part, from a wire mesh. The body 16 can also be formed from an extruded plastic or from a fibrous structure. The body 16 can also have an amorphous structure, i.e., not a regular lattice structure.

[0042] Various methods for producing the filter element 10 and in particular the support tube 14, which comprises one or more of the aforementioned materials, are conceivable. In principle, one of the following methods can be used: foaming a negative mold with an open-pore foam, extruding a plastic, filling a negative mold with a compressed foam, punching from a volume, or sintering metal and / or plastic and / or a ceramic material. Cavities 15 of the body 16 can be formed by dissolving material in a subsequent process step. The filter medium 12 is expediently applied to the surface 20 in a self-contained manner.

[0043] Fig. 2 shows an isometric view of the filter element 10 according to the embodiment in Fig. 1. The filter element 10 is designed in a longitudinal shape with a banana-shaped cross-section. The fluid to be filtered passes through the filter medium 12, which is applied flatly to the outside of the support tube 14, along the fluid path 30 from the raw side 52 and can flow inside the support tube 14 through the channels 18 formed inside the support tube 14 in the self-supporting structure 25 of the support tube 14 to an end face 22, which is designed as an outlet 32 on a clean side 50 of the filter element 10. The filter element 10 has an upper end face 23, which can be closed, for example, with an end plate.

[0044] In Fig. Figure 3 shows a cross-sectional view of a filter element 10 with a cylindrical support tube 14 according to a further embodiment of the invention. In this embodiment, the support tube 14 is also designed as a solid body 16, whose self-supporting structure 25 has three-dimensionally interconnected, interconnected channels 18 as part of a fluid path 30. Thus, conventionally cylindrical filter elements 10 can also be manufactured with the support tube 14 according to the invention.

[0045] In Fig. According to a further alternative embodiment of the invention, a filter element 10 with a flat support tube 14 is shown in cross-section in Figure 4. Even designs that fit into a relatively flat installation space of an internal combustion engine can be realized with such a support tube 14 and, despite the flat design, exhibit sufficient compressive stiffness for a filter element 10.

[0046] Fig. Figure 5 shows a cross-section through a support tube 14 according to another embodiment of the invention, which is bent at an angle. Such support tubes 14 can also be manufactured with a solid body 16 with a self-supporting structure 25. Three-dimensionally interconnected, interconnected channels 18 are formed in the interior 24 of the support tube 14 and can thus form part of a fluid path 30 for the fluid to be filtered.

[0047] Fig. 6 shows an isometric representation of a support tube 14 designed as a hollow cylinder according to an embodiment not according to the invention. The body 16 of the support tube 14 is designed as a hollow body, the wall of which is formed by the self-supporting structure 25. The filtered fluid can thus pass through the three-dimensionally interconnected, interconnected channels 18 in the interior 24 of the support tube 14 into the cavity 26 and then flow to one end face 22 or both end faces 22, 23 (for example, in a horizontal arrangement) of the support tube 14. In this way, the fluid can flow away easily because the cavity 26 offers lower flow resistance.

[0048] In Fig. Figure 7 shows a section through the spongy tissue of a long bone as an example of a coarse open-cell structure. The spongy tissue has a skeletal structure with cavities 15 and webs 17. A material with such an internal structure is particularly suitable for a support tube 14 according to the invention.

[0049] Such a structure advantageously provides three-dimensionally interconnected, interconnected channels 18 for the fluid to flow through. At the same time, the structure has sufficient rigidity to provide a self-supporting function for the body 16 of the support tube 14 and also to ensure sufficient compressive stiffness for the flowing fluid.

[0050] Fig. 8 shows a longitudinal section through a filter system 100 according to an embodiment of the invention. The filter system 100 for filtering a fluid comprises a replaceable filter element 10 and a filter housing 108 with a first housing part 109 and a second housing part 110, which enclose the inserted filter element 10. The filter housing 108 further has an inlet 102 for supplying the fluid to be filtered and an outlet 104 in a housing wall for the outflow of the filtered fluid. The filter element 10 can be flowed through from a raw side 52 to a clean side 50, with the body 16 of the support tube 14 forming part of a fluid path between the raw side 52 and a clean side 50. At least one end face 22 of the support tube 14 is connected to the outlet 104 of the filter housing 108 on the flow side.The filter element 10 sits with its lower end face 22, designed as the outlet 32 of the filter element, on a nozzle 106 of the outlet 104, which is arranged in the first housing part 109. An end plate 13 is arranged on the upper end face 23 of the support tube 14 as a closure, which is mounted in a recess in the second housing part 110. When the filter housing 108 is closed by placing the second housing part 110 onto the first housing part 109, for example by screwing or clamping, the filter element 10 is firmly clamped in the filter housing 108. The fluid to be filtered can enter the interior of the filter housing 108 through the inlet 102 of the filter housing 108 onto a raw side 52 and pass through the filter medium 12 of the filter element 10 along the fluid path 30.The filtered fluid can then flow downwards in the three-dimensionally interconnected, interconnected channels 18 of the body 16 of the support tube 14 towards the end face 22 and the outlet 32 and thus leave the filter housing 108 through the outlet 104.

[0051] The filter system 100 is in Fig. 8 with a longitudinally drawn filter element 10. This is also what a cylindrical filter element 10 would look like in section. Alternatively, however, it is also conceivable to use a filter element 10 with a non-regularly shaped support tube and thus also an irregularly shaped filter element 10 according to the invention.

[0052] Based on the ever-increasing installation space requirements of vehicle manufacturers in the course of downsizing internal combustion engines, but also due to the need for extremely compact range-extender internal combustion engines, such a filter system 100 can be advantageously adapted to the different installation spaces, both as a liquid filter and as an air filter, thus avoiding the need for unfavorable empty spaces around an internal combustion engine. Liquid filters, in particular, which are usually designed with a rotationally symmetrical filter element design, can thus be suitably designed for irregular installation spaces.

Claims

[1] Support tube (14) for a filter element (10), comprising a flow-through body (16) which is designed as a self-supporting structure (25), and wherein the body (16) has three-dimensionally interconnected, connected channels (18), characterized by that the body (16) is solid and the channels (18) are designed so that a fluid can flow through them from a flat outer side (28) of the body (16) to at least one end face (22). [2] Support tube according to claim 1, wherein the body (16) is formed at least in regions from a foam. [3] Support tube according to one of the preceding claims, wherein the body (16) is formed at least in regions from a sintered material. [4] Support tube according to one of the preceding claims, wherein the body (16) is formed at least in regions from a wire mesh. [5] Support tube according to one of the preceding claims, wherein the body (16) is formed at least in regions from an extruded plastic. [6] Support tube according to one of the preceding claims, wherein the body (16) is formed at least in regions from a fibrous structure. [7] Support tube according to claim 2 or 3, wherein the self-supporting structure (25) is formed from plastic and / or metal and / or ceramic. [8] Support tube according to one of the preceding claims, wherein the body (16) has a skeletal structure with cavities (15) and webs (17). [9] Support tube according to one of the preceding claims, wherein the body (16) has an amorphous structure. [10] Filter element (10) with a flow-through filter medium (12) for filtering a fluid with a support tube (14) according to one of the preceding claims, wherein the filter medium (12) is arranged flat on the support tube (14) and the self-supporting structure (25) of the body (16) of the support tube (14) forms part of a fluid path (30) between a raw side (52) and a clean side (50) of the filter medium (12), and wherein at least one end face (22) of the support tube (14) is provided as an outlet (32) of the filtered fluid. [11] Filter system (100) for filtering a fluid, comprising - at least one filter element (10) according to claim 10, - a filter housing (108) with a first housing part (109) and a second housing part (110), which enclose the inserted filter element (10), with at least one inlet (102) for supplying the fluid to be filtered and at least one outlet (104) in a housing wall, wherein the filter element (10) can be flowed through from a raw side (52) to a clean side (50) and the body (16) of the support tube (14) forms part of a fluid path between the raw side (52) and the clean side (50), and wherein an end face (22) of the support tube (14) is connected to the outlet (104) of the filter housing (108) on the flow side. [12] A method of manufacturing a filter element (10) according to claim 10, wherein a support tube (14) is manufactured by at least one of the methods - Foaming a negative mold with an open-pore foam, - Extruding a plastic, - Filling a negative mold with a compressed foam, - Punching out of a volume, - sintering of metal and / or plastic and / or of a ceramic material, and wherein a filter medium is applied flatly to the support tube (14) so that at least one outlet (32) is formed for the outflow of a filtered fluid from the support tube (14). [13] Method according to claim 12, wherein cavities (15) of the body (16) are formed by dissolving out material in a subsequent process step. [14] Method according to claim 12 or 13, wherein the filter medium (12) is applied in a self-contained manner to the surface (20) of the support tube (14).

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