Filter element and method for manufacturing a filter element

Abstract

The invention relates to a filter element (1) for filtering a fluid, in particular for filtering combustion air in a motor vehicle and / or for filtering a running medium of a motor vehicle, comprising a pleat pack (2) formed from a filter medium (9) folded in a zigzag, the filter medium having folding sections (22) defined by folding edges (16). At least two directly adjacent folding sections (22A, 22B) are connected to one another by means of an adhesive material (24) by way of an adhesive bond (23) along an adhesive line (21), wherein the adhesive line (21) extends at least partially obliquely relative to or offset along a folding edge (16A) between the two directly adjacent folding sections (22A, 22B).

Description

Technical Field

[0001] The present invention relates to a filter element for filtering fluids, particularly for filtering combustion air in motor vehicles and / or for filtering the operating medium of motor vehicles, and a method for manufacturing such a filter element. Background Technology

[0002] DE 10 2014 015905 A discloses a flat filter element having a filter bellows made of filter media zigzag-folded along folded edges. The folded edges extend between opposing end edges of the filter bellows. Support strips extending just beside the end edges are applied to the folded edges of the bellows, connecting adjacent folds and stabilizing the filter bellows, thereby creating a seal between the untreated air chamber and the clean air chamber. For example, in interior space air filters, the filter element can further include one or more stabilizing elements, particularly side and / or top strips (also referred to as end strips), which at least partially stabilize the filter media to maintain its shape, particularly during filter operation. These stabilizing elements can also be formed, in particular, as a single piece of material, into a closed or open frame surrounding the filter media. The disadvantage of flat filter elements according to DE 102014 015905 A is that the area in the region of the end edge cannot be used or needs to be sealed separately by side strips or similar components.

[0003] GB 2 352 195 A describes a HEPA circular filter made of glass fiber paper. Two concentric adhesive sections are provided by means of an adhesive strip to stabilize the cylindrical bellows, wherein the inner adhesive strip is thinner than the outer adhesive strip.

[0004] EP 0 645 170 B1 describes a method for manufacturing a plate-shaped filter element made from a zigzag-folded filter medium, wherein bent edges are embossed in a first working step. Two adhesive strips are then applied to the surface of the filter medium using an adhesive applicator equipped with an adhesive nozzle. Folding is then performed. The adhesive nozzle moves transversely to the transport direction of the filter material, thereby creating two parallel-extending adhesive strips, while the filter material moves along the transport direction. A cutting device divides the folded filter material transversely to the machine's operating direction into individual filter elements. Furthermore, another cutting device cuts between the parallel-extending adhesive strips. The two adhesive strips respectively form the fluid-sealed sides of the two resulting filter elements.

[0005] DE 10 2020 047 894 A1 discloses a filter element comprising a folded filter medium having pleats and pleated walls, wherein the filter medium is composed of a matrix having a side edge reinforced by a plastic reinforcement. This side edge is connected to the reinforcement, which receives the pleats and pleated walls of the filter medium. According to DE 10 2020 047 894 A1, such plastic reinforcement is fabricated as an insert, with the pleats clamped between the inserts or the insert material lockingly connected to the pleated walls. The insertion and bonding steps necessary during the manufacture of the filter element, performed from both sides of the filter medium in its folded state, for the inserts may be considered disadvantageous. Summary of the Invention

[0006] In light of this background, the objective of this invention is to provide an improved filter element, particularly a filter element that can be manufactured at low cost.

[0007] Therefore, a filter element for filtering fluids using a pleated assembly is proposed. The pleated assembly is formed of a filter medium folded in a zigzag and / or wave-like manner, the filter medium having folded sections defined by folded edges. Here, at least two directly adjacent folded sections are connected to each other along an adhesive line by means of an adhesive material. The adhesive line extends at least partially obliquely relative to the folded edge between two directly adjacent folded sections. Alternatively or supplementarily, the adhesive line extends at least partially offset along the direction of the folded edge between two directly adjacent folded sections.

[0008] The filter element is specifically designed as an ambient air filter or as a vehicle-mounted or stationary fine dust filter for filtering combustion air in motor vehicles and / or for filtering the operating medium of the motor vehicle. In one embodiment, the filter element is an air filter; in other embodiments, the filter element is configured as an interior space air filter. One embodiment is also possible as a liquid filter. A bellows is also mentioned for a pleated assembly of filter media zigzag-folded. The filter media is also referred to as filter material.

[0009] The adhesive portion is used to stabilize the pleats inside the pleated assembly, which are composed of folded edges and folded sections. Here, in the embodiment used to stabilize the pleated assembly, the adhesive portion is arranged spaced apart from at least one side of the pleated assembly or the lateral closure of the filter element. Preferably, the spacing between the adhesive portion and the corresponding side or other adhesive portion of the pleated assembly along the direction of the folded edges is chosen so that, during operation as specified, the folded edges and / or folded sections are not damaged or deformed due to the flow of the fluid to be filtered, thus preventing adverse effects on filtration quality.

[0010] The stabilizing effect manifests as an increase in the surface moment of inertia. According to the embodiment, this increases the surface moment of inertia of the filter bellows, thereby increasing its resistance to bending caused by hydrodynamic forces. Inside the bellows, the adhesive portions in the surrounding folded sections further increase the surface moment of inertia of the folded sections themselves, thereby improving their resistance to hydrodynamic bending of the folds. The combined effect of these two parts of the adhesive portion particularly improves the failure condition of excessive deformation of the element, especially when operating with a wet or damp filter element, in which case the mechanical properties of the filter material may be significantly reduced.

[0011] The adhesive portion is located inside the pleats and is preferably as far apart as the side of the filter element formed by the folded contour or the edge of the folded contour.

[0012] In embodiments with multiple internal adhesive traces, it is advantageous to divide the filter bellows into equally wide sub-segments for mechanical reinforcement. The connection between adjacent folded segments is preferably made directly between them using only the adhesive material. In this respect, the adhesive material is not used to fix additional components to the filter media, but rather represents a single-piece material connection in its hardened state.

[0013] In this embodiment, the corresponding adhesive portion made of adhesive material serves as a support, seal, and / or mechanical reinforcement of the filter medium without the presence of any other separate stabilizing components or objects within the pleats.

[0014] In one embodiment, the adhesive portion is spaced apart between two fluid-tightly sealed sides of the filter element. The sides can be sealed, for example, by side strips disposed on a folded profile of the side. Fluid-tight sealing via sealing materials, such as PUR foam, adhesives, etc., is also conceivable. The adhesive portion is attached to the seals on the sides to support the filter element separately from its outer edge, mechanically reinforce it, and / or to create targeted flow channels within the filter element.

[0015] The pleats, formed by folded edges and folded sections, are constructed transversely to the machine's direction of travel during manufacturing, with the filter medium being conveyed as a planar raw material along this direction. The adhesive portion extends partially obliquely relative to the machine's direction of travel, for example, within the range of multiple pleats with different orientations. In one embodiment, the adhesive portion extends arcuately relative to the machine's direction of travel and is equally spaced on both sides relative to the filter element or the pleat assembly. This achieves uniform support of the pleat assembly relative to the inflow and outflow surfaces of the filter element. Due to the obliquely and / or offset adhesive lines, it is possible for the adhesive portion to define segments of equal size relative to both the inflow and outflow surfaces.

[0016] An adhesive line can refer to a line or area on or above the filter medium, on which the adhesive material is coated and which acts as an adhesive relative to two folded sections. The adhesive line can extend within a range of multiple folded sections and folded edges. Thus, adjacent folded sections of the filter element are connected to each other. During manufacturing, it is preferable to apply the adhesive to the adhesive line while the filter medium is in its folded state.

[0017] The inclined or curved orientation of the adhesive line relative to the folded edges creates a stabilizing element that matches the corresponding external geometry of the filter element. This stabilizing element can flexibly adapt to the load distribution caused by pressure drop during flow. In this respect, additional stabilizing elements within the pleat assembly can be omitted, or such stabilizing devices can be more easily implemented in terms of material selection, strength, or geometry. Stabilizing the pleats within the pleat assembly via the adhesive portion allows for easy manufacturing because the adhesive can be applied along the pre-defined adhesive line before assembling the pleats. In conventional methods, additional steps for constructing additional stabilizing devices, such as those fixed to the folded edges on the inflow or outflow side, must be performed after manufacturing the pleat assembly.

[0018] In this embodiment, the adhesive material is applied to the folded sections only on either the inflow or outflow side. By applying the adhesive material to only one side, adhesive material is saved, reducing the weight increase of the filter element due to the adhesive material. The one-sided bonding of the folded sections to each other provides sufficient reinforcement along the flow direction. Furthermore, the pleats can be bent around the folded edges during one-sided coating and, if necessary, further processed into a continuous bellows.

[0019] In other embodiments, the adhesive material is arranged on both sides of the filter medium, thereby achieving particularly strong stability of the folded sections that are interconnected by means of the adhesive material.

[0020] In one embodiment, the adhesive material is continuously applied along the adhesive line between the fold edges of at least one of two folded sections defining directly adjacent folded sections. This continuous application of the adhesive material results in a particularly uniform dispersion of forces acting on the fold edges from the outside. Forces, for example in the form of gravity or bending forces, are thus distributed along the adhesive line throughout the entire bonded area.

[0021] The continuous application of the adhesive material allows for the adhesion of a fluid seal between folded sections and a certain degree of flow guidance for the fluid to be filtered inside the bellows due to the adhesive lines that are inclined relative to the machine running direction and the direction of the folded edges.

[0022] In this embodiment, the adhesive lines of directly adjacent and opposing folded sections are overlapped. This overlapped overlap allows for the use of less adhesive material. Precise bonding direction is achieved, especially when the adhesive material is previously applied to the two opposing folded sections to be joined. The adhesive lines are then arranged symmetrically with respect to each pair of folds due to their tilted or offset orientation relative to the folding edges or the machine's direction of travel.

[0023] In one embodiment, the adhesive portion is formed by two adhesive material coating portions joined together. The two adhesive material coating portions are then attached to directly adjacent and opposite folded sections and connected to each other.

[0024] In one embodiment, the adhesive lines of directly adjacent and opposing folded sections are positioned such that they are tilted relative to each other, such that the two adhesive material coatings joined together are bonded at or above the two opposing folded sections throughout the entire orientation. In this variation, continuous adhesive coating is achieved over all folded edges of the bonded folded sections, which simplifies manufacturing. The permissible offset or angle of the opposing adhesive lines of the directly adjacent and bonded folded sections is determined by the amount of adhesive coating. In the folded state, the two adhesive coatings remain in contact, so that they form a continuous bond throughout the entire orientation.

[0025] In one embodiment, the adhesive material is applied to the outwardly pointing folded edges and between adjacent folded sections.

[0026] The adhesive material is applied to the outward-pointing folded edges, enabling easy manufacturing. In the flat, folded state of the filter media, the adhesive can be applied, for example, in filaments or strips, along the entire machine's direction of travel and intersecting the fold lines. There is no need to interrupt the adhesive application on the folded edges. Furthermore, reliable reinforcement is achieved through the hardened adhesive material.

[0027] In one embodiment, the filter element includes at least two adhesive portions along their respective adhesive lines. Here, the adhesive lines are spaced apart from each other and extend at least partially obliquely relative to the folding edge between two directly adjacent folding sections or along the folding edge (16A) between two directly adjacent folding sections (22A, 22B).

[0028] Thus, the two bonded folded sections can be stabilized in shape at multiple locations through independent bonding. The extension of the filter element along the folded edges, or the width of the filter element, can be increased because the resulting spaced-apart bonded portions constitute stabilizing elements inside the bellows.

[0029] In one embodiment, the spacing between the two adhesive portions varies along the folded edges between different, especially adjacent, folded edges.

[0030] By varying the spacing between the two adhesive portions from one folded edge to the next, shape stability can be adjusted according to the local load on the corresponding folded edges. This spacing is adjusted, for example, along the machine's running direction, so that equal-length sections exist between the two adhesive portions facing the respective outer sides of the pleats and between the adhesive portions themselves. This achieves uniform load distribution on the pleats and a uniform enhancement of the filter element width through the adhesive portions.

[0031] In one embodiment, the corresponding adhesive portion extends within the range of multiple folded sections and folded edges interconnected by adhesive material, for constructing adhesive walls in the folded assembly.

[0032] As an alternative, a filter element is also proposed for filtering fluids, particularly for filtering combustion air in motor vehicles and / or for filtering the operating medium of motor vehicles. This filter element includes a group of pleats having an inflow side and an outflow side, and the pleats are formed by zigzag-folded filter media. The pleats have a height between the inflow and outflow sides, and at least one adhesive wall formed of an adhesive material extends within the pleats. The adhesive wall is formed by adhesive portions of directly adjacent folded sections.

[0033] "Adhesive wall" can refer to the total area of ​​the filter media (e.g., along the adhesive lines) coated with adhesive, consisting of a continuous region of adhesive and a series of successive folded sections along the machine's direction of travel. In this sense, a robust, stable, wall-like structure provided within the pleats and filter element—not closed off at the edges, but internally—can be termed "adhesive wall." The adhesive wall induces shape stability within the area of ​​the filter element defined by its orientation and enables targeted flow guidance within the bellows.

[0034] Here, the adhesive wall should be distinguished from known adhesive-wetted lines laid on the tips of the pleats, particularly for stabilizing circular filter elements. Such a line defines the spacing between the pleat tips relative to each other along the direction of the line. The line does not wedge into the pleats and does not stabilize them. Fluid flow is unaffected by the line.

[0035] The adhesive wall fills between 50% and 100% of the area between two folds perpendicular to the direction of operation, particularly at least 90%.

[0036] The adhesive wall makes it particularly possible to omit additional stabilizing grids placed within or on the filter element, or to construct such additional stabilizing elements more simply. The adhesive wall can advantageously extend entirely between the folded edges of the inflow side or inflow surface of the filter element and the outflow side or outflow surface, or, in an alternative embodiment, entirely between the folded edges of the outflow side or outflow surface of the filter element and the inflow side or inflow surface.

[0037] As a supplementary or alternative solution, the adhesive wall can function as a flow guiding element within the pleated assembly. By freely shaping the adhesive wall along the longitudinal side of the pleated assembly and along the flow direction transverse to the surface of the filter element, the fluid flowing through the filter element can be specifically influenced along the flow direction. Furthermore, narrowing the cross-section along the flow direction is possible to influence the flow velocity in specific regions of the filter element. This free shaping of the adhesive wall allows the flow of the filter element to be optimally matched to the housing shape and / or improves the lifespan of the filter element.

[0038] In one particular embodiment, the adhesive walls intersect and thus form individual flow-through regions within the pleated assembly. The segments formed by the regions surrounded by the adhesive walls are able to be selectively directed to the flow through corresponding housings having inlets and outlets.

[0039] Here, the adhesive wall can be tilted along the flow direction and / or the machine running direction in order to ensure the best possible flow distribution and / or flow velocity.

[0040] In one particular embodiment, the inclination of the adhesive wall relative to the surface normal N of the outflow or inflow side varies, for example, from 45° to -45° along the length of the pleats.

[0041] The interior of the filter element is formed, for example, by an inflow surface and an outflow surface, and by a lateral fluid seal of a group of pleats or by a defined portion formed by a filter medium, wherein the inflow surface and the outflow surface are formed by a large number of folded edges visible from the outside. "Interior" can also be understood as the area of ​​the filter element that cannot be easily manipulated from the outside.

[0042] In one embodiment, the filter element has a width along the folded edge, a length extending laterally to the width, and a height corresponding to the fold height. Here, the filter element can be squarely constructed with a rectangular planar shape, but may also enclose an irregular space due to structural space requirements. A trapezoidal planar shape, for example, on the inflow and / or outflow sides, is conceivable, or a fold height varying within a length range and thus a filter element height varying within a length range is also conceivable.

[0043] In one embodiment, the adhesive wall extends between the inflow side and the outflow side and is able to connect the inflow side and the outflow side to each other, particularly completely, between the folded edges of the inflow side or inflow surface and the outflow side or outflow surface of the filter element.

[0044] As an alternative, the adhesive wall extends between the outflow side and the inflow side and is able to connect the outflow side and the inflow side, particularly completely, between the folded edge of the inflow side or inflow surface of the filter element and the outflow side or outflow surface.

[0045] In one embodiment, the adhesive wall includes inflow-side edges and / or outflow-side edges, wherein the inflow-side edges restrict the inflow surface of the filter element, and / or the outflow-side edges restrict the outflow surface of the filter element. The respective edges can form a closed profile or, together with other lateral restraint elements, such as side strips or seals, define a cross-section along the flow direction.

[0046] The inflow and outflow surfaces of the filter element can have different dimensions and / or geometries. Adjustments to these shapes can advantageously influence the flow.

[0047] The corresponding adhesive wall is specifically configured as a flow guiding element within the pleats. Here, the adhesive wall is constructed spaced apart from the edges of the pleats and attached to the seals on the sides of the edges of the pleats. Furthermore, the adhesive wall can have other properties, such as stabilizing effects or additional sealing functions.

[0048] In one embodiment, the adhesive wall at least partially separates the pure fluid region from the unpurified fluid region. This separation enables specialized structural forms, such as filter elements with internal fixing devices, like rods or perforations.

[0049] In this embodiment, the adhesive wall has at least a portion of an angle between 5° and approximately 90°, preferably between 10° and 45°, and particularly preferably between 10° and 30°, along the plane normal relative to the inflow or outflow side. Such an angle allows for localized acceleration or deceleration of the fluid along the flow path within the filter element. With the inlet and outlet ports of the filter housing facing opposite orientations, this flow displacement can lead to a reduction in pressure loss of the filter element and / or a homogenization of the flow pattern on the inflow and / or outflow surfaces.

[0050] The adhesive wall divides the pleats, particularly along their width, into pleat sections. This division of the pleats by the adhesive wall improves the shape stability of the corresponding pleat sections. The adhesive wall, due to its inclined or offset orientation relative to the machine's running direction or the direction of the pleat edges, can be matched to the variable width of the filter element. Therefore, the division of the pleat sections along their width can be matched to the predetermined local pressure drop during operation through the filter receiving section and its inflow or outflow characteristics. Overall, filtration performance is thus improved.

[0051] In this embodiment, the adhesive wall extends obliquely and / or curvedly along the height direction. The oblique and / or curved orientation of the adhesive wall along the height direction achieves flexible, matching shape stability. Furthermore, it enables the guidance of the fluid to be filtered within the pleated assembly. This improves filtration characteristics and achieves effective internal flow guidance.

[0052] In this embodiment, the adhesive walls extend obliquely and / or curvedly along their length. This allows for improved shape stability and conformable flow.

[0053] In one embodiment, the height of the adhesive wall is at least partially smaller than the height of the filter element.

[0054] In other embodiments, the adhesive wall is interrupted in at least one region along the machine's direction of travel.

[0055] In this respect, the height of the adhesive wall can be partially reduced relative to the height of the filter element. This allows for the saving of adhesive material in areas of the filter element where the load is relatively small. Consequently, the filtration area for filtering the fluid is increased because less filter material is enclosed by the adhesive.

[0056] Furthermore, by periodically interrupting the adhesive coating in the areas of the folded edges on the inflow and / or outflow sides, an adhesive wall with reduced height can be formed.

[0057] In one embodiment, the adhesive wall is interrupted along the length of the filter element. In other embodiments, the adhesive wall is spaced apart from the end side of the filter element.

[0058] As an end side, for example, it can refer to the closure formed by an end pleat or an end pleat section of the pleated assembly. Alternatively, a top band may form the end side. The direction of the interruption in the adhesive wall allows the pleated assembly to remain stable in its shape, especially in areas subjected to loads due to external requirements.

[0059] In this embodiment, the adhesive walls in the pleated assembly have a closed shape. Here, the adhesive walls can extend along irregular, closed curves. This not only improves the flow characteristics of the filter element but also enhances its shape stability. The closed adhesive wall structure is thus self-supporting and particularly stable.

[0060] The shape stability of the pleated group and a special flow guide are achieved through the adhesive wall. In this way, the external inclined cut geometry of the filter element can be effectively achieved without adjusting the geometry and installing additional sealing components in additional steps.

[0061] In this embodiment, multiple adhesive walls are provided. These multiple adhesive walls can intersect.

[0062] The intersection or contact of multiple adhesive walls further enhances the shape stability of the pleats. Complex load distributions acting on the filter element from the outside can therefore be intercepted by the geometry of the adhesive walls. In this respect, the adhesive walls can form a complex internal support grid within the bellows.

[0063] In one embodiment, the width of the filter element is uniformly divided along its length by the spacing between the adhesive walls and the spacing between the adhesive walls and the sides of the filter element.

[0064] By uniformly dividing the width of the filter element along its length, the load-bearing capacity and stability of the particularly wide filter element are improved, because the lever length for the maximum occurrence of bending force that constitutes the bending moment around the pleated area fixed by reinforcement measures is minimized when the element is uniformly divided.

[0065] The adhesive walls, whose geometry is flexible, can improve not only the stability of the filter element but also its filtration characteristics. Furthermore, the adhesive walls form both a stabilizing element and a flow-guiding element that can be manufactured inexpensively.

[0066] In one embodiment, the pleats are bent into a continuous bellows in a cylindrical shape. Specifically, the end pleated sections of the pleats are fluid-tightly connected to each other.

[0067] By means of a corresponding continuous corrugated tube, a circular filter geometry can be achieved, for example. Optionally, an end disc can be mounted on a folded profile, the end disc forming a corresponding cover surface of a cylindrical circular filter element.

[0068] Due to the adhesive portion, a stable adhesive wall can be constructed, corresponding to the complex shaped surfaces inside the bellows. Due to the supportive adhesive wall, for example, internal or external support tubes that abut against internal or external folded edges can be abandoned, or such support elements can be designed to be at least weaker or smaller.

[0069] In embodiments, the adhesive material includes solvent-containing wet adhesives, contact adhesives, dispersion adhesives, melt adhesives, hot melt adhesives, plastisols, addition adhesives, condensation adhesives, polymeric adhesives, or pressure-sensitive adhesives.

[0070] It is conceivable to use adhesive materials containing polyamides. In an embodiment, the adhesive material is a hot melt adhesive composed of thermoplastic materials, particularly polyamide-melt resin.

[0071] The filter medium can be folded or corrugated. Pleats include, for example, known zigzag or W-shaped pleats. The filter medium can be embossed and then folded at the embossed edges while constructing folded edges. Sheet-like material filters can be used as raw materials, which are then shaped accordingly. The filter medium is preferably made of wet-laid, impregnated filter paper with a high cellulose content.

[0072] The filter medium is, for example, filter cloth, filter gel, or filter nonwoven fabric. The filter medium can be manufactured, in particular, by spunbonding or meltblown methods. The filter medium can contain cellulose, natural fibers such as cotton, or synthetic fibers such as polyester, polyphenylene sulfide, or polytetrafluoroethylene.

[0073] The filter medium can be single-layered or multi-layered. Furthermore, it can contain an adsorbent, such as activated carbon.

[0074] A corresponding filter element is used to filter fluids, i.e., gaseous and / or liquid media, such as air. Gaseous media or air here also include gas-or air-solid mixtures and / or gas-or air-liquid mixtures. The filter media can be configured to remove particles from an airflow.

[0075] In this embodiment, in addition to the adhesive portion or adhesive wall serving as a stabilizing element within the filter element, the filter element includes one or more additional stabilizing elements. These stabilizing elements are capable of at least partially stabilizing the filter media in order to maintain its shape, particularly during filtration operation. These additional stabilizing elements can, in particular, form a closed or open frame, or can be constructed as a single piece of material, the frame surrounding the filter media.

[0076] The additional stabilizing element can be locked onto, in particular bonded to, the filter media material at its edge. To do this, the stabilizing element can be heated and the filter media pressed into the heated material. Alternatively, the additional stabilizing element can be sprayed onto the filter media. Furthermore, an adhesive can be used as an additional material. The additional stabilizing element itself can be made of the same material as the filter media. Alternatively, the additional stabilizing element can be constructed as a plastic injection-molded component. The additional stabilizing element can be rigid or flexible.

[0077] Furthermore, the filter element can have a seal that seals the untreated side of the filter element relative to the clean side of the filter element. The seal can be constructed using one or more additional stabilizing elements of the filter element. Alternatively, the seal can be configured as an additional component. Therefore, the seal can be, for example, placed on the filter media, one or more additional stabilizing elements, the filter element, or the filter receiving portion.

[0078] The filter element can be replaced and fixed in the filter receiving part.

[0079] In addition, a filter assembly is proposed having a filter element as described previously or below and a filter receiving portion, for example, in the form of a housing.

[0080] The filter elements or filter assemblies described herein can be used in passenger cars, trucks, construction machinery, ships, rail vehicles, and aircraft, and are generally applicable in air conditioning technology, particularly in heating and air conditioning equipment, in household appliances, in fuel cells, or in building technology. These vehicles or vehicles can be operated electrically and / or by means of fuel (especially gasoline or diesel). Regarding building technology, stationary equipment for air handling is particularly considered.

[0081] Furthermore, a method for manufacturing filter elements is proposed. In this manufacturing method, the following steps are performed: providing a flat filter medium; applying an adhesive material along a pre-defined adhesive line; folding the filter medium along a pre-defined fold line, adjacent folded sections being defined by the pre-defined fold line. This, in particular, constructs folded edges between the folded sections. In another step, the adhesive material is hardened to form an adhesive portion between adjacent folded sections. The adhesive material is applied to the corresponding adhesive line in this method such that the adhesive line extends at least partially obliquely to or offset along the fold line between the corresponding adjacent folded sections, wherein a spacing relative to the edge of the filter medium is observed.

[0082] The manufacturing method is particularly used for manufacturing filter elements as described previously or below.

[0083] Preferably, the application of the adhesive material is performed before the step of constructing the folded edges. In other words, the folding or wrinkling of the flat filter media is performed after the adhesive material is applied.

[0084] A fold line can refer to a line that is constructed into a folded edge through a folding process. In other words, the fold line and the folded edge coincide in the folded state of the filter medium. The fold line, in this sense, defines the position and direction of the folds by virtue of the folded edge.

[0085] For example, the following lines or curves on the filter medium are considered adhesive lines, along which the filter medium is covered with adhesive material. Depending on the consistency of the adhesive coating, the adhesive coating can be referred to as adhesive filaments, adhesive strips, etc.

[0086] By applying the adhesive material at an angle to or partially offset relative to the fold line, the following orientation of the adhesive material can be achieved through a manufacturing method, which, taking into account the shape of the filter element, provides support for the filter element. Preferably, it is possible to omit additional support elements added to or placed on the filter element. In any case, the corresponding adhesive portion causes stability of the folds.

[0087] The thickness of the adhesive portion or the geometry of the adhesive line of the filter element can be matched to the load acting on the filter element from the outside. The load is generated in particular by the pressure drop between the clean side and the untreated side of the filter element during operation. For example, the thickness of the adhesive coating portion can vary along the direction of the adhesive line to create an internal support grid structure with different stability.

[0088] In embodiments of the method, the adhesive material is applied in a flowable state. Here, for example, with thermal adhesives, the viscosity can be adjusted by temperature and / or composition to achieve the desired adhesive coating.

[0089] In embodiments of the method, the adhesive material is applied by means of a coating nozzle movable along the fold line, particularly by continuous extrusion. Therefore, the thickness of the adhesive coating along the fold line can be controlled.

[0090] The adhesive coating nozzle, which can move laterally to the direction of machine operation, enables the adhesive line to have a flexible orientation relative to the folded line that also extends laterally to the direction of machine operation.

[0091] As an alternative, nozzles that can tilt or otherwise move laterally to the direction of machine operation can be used to achieve flexible routing.

[0092] In an embodiment of the method, the application of the adhesive material is interrupted at least partially along the adhesive line. This interruption of the adhesive line allows the adhesive portion to be confined to areas of the filter element that are particularly subjected to load.

[0093] In an embodiment of the method, the flat filter media is conveyed along the machine's running direction, which extends transversely to the fold line. Therefore, it is sufficient to move the coating nozzle back and forth in a direction transverse to the direction of the filter media and, if necessary, interrupt the adhesive spraying to create complex geometries. This simplifies the production line structure.

[0094] In embodiments of the method, the adhesive material is simultaneously applied along different adhesive lines. For example, multiple coating nozzles can be used side-by-side or sequentially along the machine's direction of travel. This allows multiple adhesive walls to be created simultaneously and side-by-side.

[0095] In an embodiment of the method, one or more of the following method steps are performed: imprinting the filter medium along the fold line; fixing the folded filter medium during the curing of the adhesive material; placing side strips onto the folded profile of the side; and / or cutting the folded filter medium with adhesive portions to form a pleated assembly.

[0096] The methods and steps mentioned above can be implemented in the order described. However, different sequences are also possible. For example, the placement of the side straps can also be performed after cutting the pleats.

[0097] Furthermore, it is suggested that the filter elements explained above or below be used in a method for filtering fluids. In this filtration method, the fluid to be filtered within the pleated assembly is guided by flow-guiding elements, which are preferably formed from adhesive walls as described previously.

[0098] Other possible implementations of the invention also include combinations of features or method steps not explicitly described above or below with respect to the embodiments. Those skilled in the art will also consider individual aspects as improvements or supplements to the corresponding basic forms of the invention. The aspects, advantages, and effects explained with respect to the filter element also apply to the corresponding aspects of the manufacturing method, and vice versa. Attached Figure Description

[0099] Other design options of the present invention are the subject of the dependent claims and the embodiments described below. The invention will now be explained in detail with reference to the accompanying drawings and embodiments.

[0100] Here:

[0101] Figure 1 A perspective view of a first embodiment of the filter element is shown;

[0102] Figure 2 It shows what is suitable for following Figure 1 A three-dimensional view of the pleated assembly of the filter element;

[0103] Figure 3 A perspective view of a filter assembly having a filter housing and filter elements is shown in one embodiment;

[0104] Figure 4 It shows that it has according to Figure 3 A schematic diagram of a motor vehicle with a filter assembly;

[0105] Figure 5 A three-dimensional view showing the adhesive walls is provided in accordance with... Figure 1 The cut-off portion of the pleated assembly used in the filter element;

[0106] Figure 6 It shows along in Figure 5 A three-dimensional view of the cross-section AA of the adhesive wall;

[0107] Figure 7 A cut portion of an undraped filter medium with different adhesive lines is shown;

[0108] Figure 8 It shows according to Figure 7 Detailed view of the filter media;

[0109] Figure 9 The method steps of one embodiment of a method for manufacturing a filter element are shown;

[0110] Figure 10 It shows the method for implementing according to Figure 9 A schematic diagram of the apparatus used in the manufacturing method;

[0111] Figure 11A A perspective view of a second embodiment of a filter element having an adhesive wall extending through the filter element and a trapezoidal planar shape is shown;

[0112] Figure 11B It shows according to Figure 11A A top view of the filter element;

[0113] Figure 11C It shows the method for following Figure 11A A top view of the filter element's folded filter media;

[0114] Figures 12A-12C A perspective view and a top view of a third embodiment of a filter element with an irregular planar shape are shown, along with the associated folded filter medium.

[0115] Figures 13A-13C A perspective view and a top view of a fourth embodiment of a filter element with intersecting or contacting adhesive walls are shown, along with the associated folded filter media.

[0116] Figures 14A-14C A perspective view and a top view of a fifth embodiment of a filter element having intersecting, arc-shaped adhesive walls, and the associated folded filter media are shown.

[0117] Figures 15A-15C A perspective view and a top view of a sixth embodiment of a filter element having a highly inclined adhesive wall are shown, along with the associated folded filter media.

[0118] Figures 16A-16C A perspective view and a top view of a seventh embodiment of a filter element are shown, along with the associated folded filter medium, the filter element having an adhesive wall wound along the length of the filter element.

[0119] Figures 17A-17C An eighth embodiment of a filter element is shown in perspective and top view, along with the associated folded filter medium, the filter element having a laterally closed adhesive wall along its obliquely cut side.

[0120] Figures 18A-18CA perspective view and a top view of a ninth embodiment of a filter element and the associated folded filter medium are shown, the filter element having an adhesive wall along the side of a beveled side of the filter element, the adhesive wall having a tapering cross-section along its length.

[0121] Figures 19A-19C A perspective view and a top view of a tenth embodiment of a filter element as a circular filter element are shown, along with the associated folded filter medium, the filter element having a spirally extended adhesive wall.

[0122] Figures 20A-20C A perspective view and a top view of an eleventh embodiment of a filter element as a circular filter element are shown, along with the associated folded filter medium, the filter element having intersecting, spirally extending adhesive walls.

[0123] Figures 21A-21C A perspective view and a top view of a twelfth embodiment of a filter element as a circular filter element are shown, along with the associated folded filter medium, the filter element having intersecting, spirally extending adhesive walls.

[0124] In the accompanying drawings, unless otherwise specified, the same or functionally equivalent elements are given the same reference numerals. Detailed Implementation

[0125] Figure 1 A first embodiment of the filter element 1 is shown. The filter element 1 comprises a flat filter medium 9 folded into a pleated assembly 2, the filter medium 9 being surrounded by side and top bands 11, 12, 13, and 14. The pleated assembly 2... Figure 2 It is shown without frame 7. Figure 1 The side straps 11, 12 shown are connected to the folded end edges or external folded contours 19, 20, and the top straps 13, 14 are connected to the end folds 17, 18, particularly by melting, welding, or bonding. The side straps 11, 12 and the top straps 13, 14 can form the frame 7 as a single piece or as multiple components. The side straps 11, 12 and the top straps 13, 14 can be made, for example, from particularly flexible fibrous materials or as particularly rigid plastic injection-molded components and form the surrounding frame 7. Alternatively or supplementarily, such a frame 7 can also be produced by spraying it onto the filter medium 9.

[0126] The adhesive wall 3 extends obliquely through the pleats 2 between the top bands 13 and 14, separated from the side bands. The adhesive wall 3 separates the pleats 2 and reinforces them in a folded manner. The adhesive wall 3 is formed by adjacent folded sections connected to each other and relative to... Figure 2 The machine's running direction M, as outlined in the diagram, extends at an angle. The adhesive joints between the folded sections are also angled relative to the folded edges 16. The adhesive joints on the surface of the filter medium 9, formed by means of adhesive material along the adhesive lines, serve to stabilize the pleats and can be understood as internal support elements.

[0127] Figure 2 This illustrates a filter medium 9 folded as a pleated assembly 2, which can be used in accordance with... Figure 1 In the filter element, the adhesive portion used to form the directly adjacent folded sections of the adhesive wall for stable bonding is not in... Figure 2 As shown in the diagram, the filter medium 9 is zigzag-folded into pleat group 2 and has a plurality of parallel pleats 15 extending transversely to the machine running direction M. When pleats 15 are formed, the flat filter medium 9 is compressed along the machine running direction M, thereby establishing the pleats 15. The folded filter medium 9 is also referred to as a pleat. The pleats 15 can be formed by folding along sharp folding edges 16 (also referred to as pleat tips) or by a wave-like implementation of the filter medium 9. A corresponding pleat 15 is defined by two directly adjacent pleat segments 22 connected to each other by corresponding folding edges 16. Adjacent folding segments 22A and 22B are here adjacent to each other by a common folding edge 16C. The orientation of the pleats 15 alternates along the machine running direction M to form a zigzag pattern. The pleat spacing between adjacent folding edges with the same orientation is denoted by a1 and a2.

[0128] The zigzag fold outlines 19 and 20 are visible from the side, limiting the fold group 2 on the sides. The end sides are formed by end fold sections 17 and 18. The fold group 2 here encloses a cuboid space with a rectangular base surface, the base surface having a length l along the machine running direction M or transverse to the fold extension and a width b along the fold edge 16. The fold group 2 also has a height h, which is derived from the fold height and fold angle. Along Figure 2 The fluid to be filtered, especially combustion air, flows upward through the pleated assembly 2. Here, the folded filter media 9 separates the untreated fluid zone RO and the pure fluid zone RE.

[0129] Figure 3 The filter assembly 6 is schematically shown, wherein according to Figure 1The filter element is received within the filter housing 10. Air L to be filtered flows from the untreated side RO of the filter element 1 to the clean side RE of the filter element. To ensure sufficient lateral sealing between the untreated side RO and the clean side RE, a seal 9A can be provided between the filter element 1 and the filter housing 10. This seal 9A is, for example, constructed as a foamed PUR seal.

[0130] Figure 4 A motor vehicle 4 is shown with a corresponding filter assembly 6 for filtering combustion air. Here, a suction device draws in outside air 5 and delivers it to the filter assembly 6. The filtered clean air 8 is then delivered to the vehicle's internal combustion engine.

[0131] Especially when filter element 1 is used in a filter assembly 6 for filtering combustion air in a motor vehicle, filter element 1 is subjected to a high pressure difference between the untreated air side RO and the clean air side RE. Particularly in the middle of the inflow surface, the pressure drop between the untreated side and the clean side RO and RE can cause forces to deform the pleats and thus impair filtration performance, which are then exerted on filter element 1. To internally reinforce the pleat assembly 1 and support the pleats under load during operation, as in... Figure 1 As depicted as adhesive wall 3, adhesive portions are provided between adjacent folded sections along the machine's running direction. Furthermore, the adhesive wall 3 functions as a spacer for opposing folded sections. Additionally, other external support elements, such as stabilizing grids or rigid comb structures embedded in the folds, can be provided on the filter element 1.

[0132] exist Figure 1 In this embodiment, adhesive materials are now used to create adhesive portions between adjacent folded sections and folded edges. This is in... Figure 5-8 A detailed explanation follows. The adhesive material is a hot melt adhesive, which is applied in liquid or paste form along the adhesive lines before folding the filter media 9.

[0133] exist Figure 5 The text shows the following: Figure 1 The cut-off portion of the pleated assembly 2 in the first embodiment of the filter element. An adhesive wall 3, formed by the hardened adhesive material 24 and the area of ​​the filter medium 9 wetted by the adhesive material 24, extends through the interior of the pleated assembly 2. The wetted area follows the adhesive line 21 on the filter medium 9. An exemplary flow direction F is outlined, thus along... Figure 5 The orientation generates the lower inflow side 2A and the upper outflow side 2B of the pleats 2.

[0134] Figure 6A cross-sectional view AA along the adhesive wall 3 is shown for the pleated group 2. The adhesive wall 3 extends completely between adjacent folded sections 22 separated from each other by folded edges 16 and connects them as adhesive portions 23. The adhesive wall 3 follows the shape of the pleats and maintains the pleats in its cross-section. Figure 6 The height of the adhesive wall 3 shown corresponds to the fold height, wherein a portion of the adhesive wall 3 additionally covers the upper folded edge 16'. The adhesive wall 3 extends within the range of a plurality of adjacent folds, each consisting of two folded sections 22 and a folded edge 16.

[0135] The adhesive portion 23 is achieved by applying at least one adhesive coating portion close to each other along the adhesive line onto adjacent folded sections. Through a folding process along the lower fold line, which forms the folded edge 16A, the opposing sides of at least one adhesive coating portion are joined together and a fixed connection is created along interface 23A. Figure 6 Draw the middle part on the right side.

[0136] To explain the orientation of the adhesive portion 23 in the pleats, Figure 7 and 8 An adhesive line and a fold line are shown, wherein the adhesive coating portion 26 and then the adhesive portion 23 are completed along the adhesive line, and the fold line is then defined as a folded edge 16 on the surface of the filter medium 9.

[0137] Therefore, in Figure 7 The image shows an unfolded filter medium 9. Fold lines extend across the filter medium 9 between the folded sections, with only a selected portion of each folded section marked by reference numeral 22. These fold lines are shown as dashed lines 16A and dotted lines 16B and 16C. Two adjacent folded sections 22A and 22B are separated from each other by folding edges 16A. Furthermore, the adjacent folded sections 22A and 22B are defined by two folding edges 16B and 16C adjacent to each other.

[0138] also, Figure 7 Three exemplary adhesive lines 21A, 21B, and 21C are shown. Along the adhesive lines, corresponding adjacent folded sections are connected to each other by adhesive material applied thereto, thereby forming adhesive walls.

[0139] The adhesive line 21A extends obliquely relative to the folded edge and obliquely relative to the machine running direction M within a limited number of folded sections 22. In the folded state, this creates an adhesive wall that extends obliquely relative to the machine running direction and extends over the entire height of the folded group, but not over its entire length.

[0140] The adhesive line 21B is waveform-shaped in all of them. Figure 7 The adhesive line 21B extends within the range of the folded section 22 shown. For each corresponding adjacent folded section 22A, 22B, the adhesive line 21B extends in a mirror-symmetric manner with respect to the folded line 16A that separates them. As a result, the adhesive traces applied to the adhesive line 21B overlap and form an adhesive wall that extends across the length of multiple adjacent folded sections.

[0141] The adhesive line 21C extends in a zigzag pattern and is mirror-symmetrically formed in the corresponding adjacent folded sections 22A, 22B with respect to the fold line 16A that separates the folded sections. This achieves a precise and reliable adhesive joint. Furthermore, the adhesive line 21C is interrupted at two points 25 in the region of the fold line.

[0142] The adhesive lines 21A, 21B, and 21C extend partially at an angle relative to the corresponding folded edge 16A, wherein the folded edge 16A is located between corresponding adjacent folded sections 22A and 22B. Figure 8 The corresponding adhesive coating applied to the corresponding adhesive line is illustrated. Folded sections 22A-22D, defined by fold lines 16A-16D, are shown enlarged. Here, the adhesive material coating is shaded along the corresponding adhesive line to the right of fold line 16B. To the left of fold line 16B, the corresponding adhesive line without adhesive coating is shown. Adhesive line 21C corresponds to... Figure 7 The adhesive lines shown extend in a zigzag pattern along the direction of machine operation. Adhesive materials 26C and 26D are applied to the folded sections 22C and 22D, which overlap and bond together for bonding.

[0143] As an alternative or supplementary solution, the adhesive line extends offset along the fold edge 16A portion located between adjacent fold sections 22A and 22B. The segments of the adhesive line 21D applied to different fold sections are offset from each other along the direction of the fold line, this offset being denoted by 'a'. The resulting adhesive portion is then displaced from fold edge 16B to fold edge 16D by an offset of 'a'. This results in a composite adhesive wall that extends obliquely relative to the longitudinal direction of the fold assembly.

[0144] Another embodiment shows the adhesive line 21E, which extends obliquely over multiple fold lines relative to the machine running direction, thereby forming a curved adhesive wall along length l in the folded filter pack, wherein the adhesive strips on adjacent folded sections of the adhesive wall do not overlap or only partially overlap.

[0145] The following uses Figure 9 and Figure 10 To describe a method for manufacturing, for example, in Figure 1 The method of the filter element shown. Figure 9 The possible sequence of method steps is shown and Figure 10 An apparatus for carrying out the manufacturing method is schematically shown.

[0146] In the first step S1, the flat filter medium 9 is provided. For this purpose, the filter medium is conveyed to a conveying device, for example, as a roll material. For this purpose, it is possible to first pass it through roller 30 as in... Figure 10 The continuous filter media shown is flattened and / or pre-pressed and conveyed along the machine running direction M.

[0147] In step S2, the adhesive material 24 is applied to the filter medium 9 along a pre-defined adhesive line. The adhesive line extends obliquely relative to the machine running direction M and relative to the folds to be formed, for example, as in… Figure 7 and 8 As depicted in the description. In the described embodiment, the adhesive is configured as a hot melt adhesive and applied as an adhesive filament to the conveyed filter media via a dispensing nozzle 31 that is movable transversely to the machine's running direction M. The dispensing nozzle, for example, allows for rapid on / off switching of the adhesive application. It is conceivable to use multiple adhesive nozzles in parallel, where molten hot melt adhesive is simultaneously applied along different adhesive lines. The application can be automated through program control. The appropriate amount of coating is dispensed so that the adhesive filament exiting the dispensing nozzle has the corresponding desired thickness. When using multiple nozzles, these nozzles can be laterally recessed, thereby enabling overlapping adhesive marks.

[0148] In another step S3, the filter medium 9, which is loaded with traces of adhesive material, is folded by the folding device 32. The fold lines 16 can be pre-imprinted here. By folding, the coated and uncured adhesive traces converge on opposite folded sections to form an adhesive portion. This creates the shape and structure of the pleats.

[0149] Next, in step S4, the adhesive material present in the folded filter media 9 is hardened. This can be done, for example, by cooling the hot melt adhesive with a blower 33.

[0150] The pleated assembly, stabilized by the adhesive walls, is cut into the shape necessary for the respective application using the shearing device 34. Furthermore, for further stabilization, side straps, top straps, and / or sealing frames can be attached to the pleated assembly.

[0151] Other embodiments of filter elements for air filters are explained below, wherein the filter elements have different geometries and orientations of the adhesive walls serving as internal support elements. Here, repeated elements are explained only when mentioned for the first time, and the corresponding reference numerals are used thereafter.

[0152] Figure 11A A perspective view of a second embodiment of the filter element 1 is shown. Figure 11B The text shows that in Figure 11A The filter element 1 is shown in top view. The filter element 1 has a surrounding polyurethane foam seal for fixation and for sealing between the untreated material side and the purified material side. Within the area of ​​the folded contours (19, 20) outside the pleats, the seal between the untreated air area and the purified air area is achieved by a fluid-sealed adhesive wall (not shown). Figure 11A and Figure 11B The filter element 1 shown has two adhesive walls 3 extending along the length l of the filter element 1. The adhesive walls 3 evenly divide the pleated group 2 into three pleated sections 27 along the width b within the extension range of the length l. Here, the adhesive walls 3 extend from a front end pleat 17 of the pleated group 2 to a rear end pleat 18 opposite it. The two adhesive walls 3 extend obliquely relative to the successive folded edges 16. This... Figure 11C As shown in the image. Figure 11C The unfolded filter medium 9 is shown. The fold lines 29 predetermine the orientation of the fold edges 16, in which... Figure 11A Only one selection portion is explicitly shown. The two adhesive lines 21A and 21B are inclined relative to the fold line 29. Furthermore, in Figure 11C Cutting line 28 is drawn in the middle. Cut along this line the glued pleats 2 to obtain a trapezoidal planar shape.

[0153] exist Figure 12A A perspective view of a third embodiment of the filter element 1 is shown. Figure 12B In the top view, the area XII marked with a dashed line is... Figure 12CThe image is shown as an enlarged section of the unfolded filter medium in a detailed view. In this embodiment of the filter element 1, the adhesive wall 3 extends in a curved and / or inclined manner along the length l of the filter element 1. Therefore, the adhesive wall 3 can match the predetermined curved outer contour of the pleated group 2. To stabilize the pleated group 2, it is divided into suitable, equally wide pleated group sections 27. Preferably, the adhesive wall extends exactly in the middle between the two sides of the pleated group 2.

[0154] Figure 13 illustrates a fourth embodiment of filter element 1. Figure 13B As can be seen in the top view, the adhesive walls 3 intersect and form a grid throughout its entire height within the pleats, and are fluid-tightly constructed. Figure 13C It shows in Figure 13B Detailed view of the section XIII marked in the figure. The segment formed by the region 27 surrounded by the adhesive wall 3 can be targeted to meet the flow through the corresponding housings having inlets and outlets.

[0155] Figure 14 shows a fifth embodiment of the filter element 1, in which two adhesive walls extend sinusoidally along the length of the filter element 1. Figure 14C It shows in Figure 14B Detailed view of the section XIV marked in the figure. The two adhesive walls 3 are separated from the lateral edges of the filter element 1 and, in particular, stabilize the pleated group in the middle along the longitudinal axis.

[0156] Figure 15 shows a sixth embodiment of the filter element 1. In this embodiment, two adhesive walls 3 extend parallel to each other. The adhesive walls 3 extend side-by-side along the length l of the pleated group 2. Here, the adhesive walls 3 are inclined relative to the height h of the pleated group 2. Here, the adhesive walls 3 connect the inflow side 2A and the outflow side 2B of the filter element 1. This inclination provides a flow (direction) guide between the inflow and outflow sides as air flows through. This allows for a specific flow profile to be achieved in the inflow or outflow surface. The two adhesive walls 3 form an angle α of approximately 45° with the plane normal N of the outflow side 2B (and the inflow side 2A). The internal regions I, II, and III defined by the adhesive walls 3 have different flow characteristics. The cross-sectional area during flow is constant for region II, while the cross-sectional area of ​​region I increases. The cross-sectional area of ​​region III decreases during flow. This causes the flow velocity to decrease along the height from the inflow side 2A to the outflow side 2B in region I and to increase in region III. The adhesive wall 3, acting as an internal flow guiding element, allows for a flow distribution within the filter element 1 that matches the corresponding installation condition.

[0157] In an alternative embodiment (not shown), the adhesive wall 3 is capable of having an angle α with opposite inclinations, for example, 45° and 315° (“-45°”), with respect to the plane normal N of the outflow side 2B (and the inflow side 2A).

[0158] The angle α of the adhesive wall 3 can be varied along the length l of the pleat group 2. The adhesive wall 3 can be inclined, that is, not parallel to each other and inclined relative to the outer edge of the pleat group 2.

[0159] Figure 16 shows a seventh embodiment of the filter element 1. The adhesive wall 3, extending along the longitudinal direction, is twisted, thereby changing its inclination relative to the height direction. Thus, the adhesive wall 3 achieves internal reinforcement of the pleated group and simultaneously facilitates flow.

[0160] The eighth embodiment of the filter element 1 shown in Figure 17 includes two inclined adhesive walls 3. The adhesive walls 3 are arranged obliquely relative to the height h of the pleats and are inclined in the opposite direction. The adhesive walls 3 form fluid-tight sidewalls of the filter element 1. The adhesive walls provide a fluid-tight seal to the filter element 1 on the sides. Furthermore, a cutting line 28 is indicated, which extends parallel to the adhesive line 21 and is slightly offset laterally outward.

[0161] The ninth embodiment of the filter element 1 shown in FIG. 18 largely corresponds to the seventh embodiment. Furthermore, the width of the filter element 1 varies along its length. In the orientation of FIG. 18, the fluid flows from bottom to top, thus the inflow side 2A is below and the outflow side 2B is above. The inflow surface A1 and the outflow surface A2 are defined by the adhesive wall 3 or its edges 3A, 3B. It can be seen that the inflow surface A1 is smaller than the outflow surface A2. Due to the increased cross-sectional area during flow, the flow velocity of the fluid to be filtered decreases.

[0162] This implementation achieves improved utilization of the structural space in such a way that the largest possible filtration area can be obtained within a given structural space.

[0163] In other embodiments, a cylindrical filter element 1 is implemented. Here, the pleated assembly 2 is bent into a continuous bellows in the shape of a cylinder. For this purpose, the end pleated sections 17 and 18 are hermetically connected to each other to construct a circular filter element. The corresponding adhesive wall 3 then extends radially between the inner and outer folded edges.

[0164] exist Figures 19A-19CThe tenth embodiment is shown, wherein the adhesive wall 3 extends spirally along the height H of the cylindrical filter element 1. The continuous adhesive wall 3 provides a stabilizing effect relative to the forces acting radially and axially on the filter element 1.

[0165] exist Figures 20A-20C The eleventh embodiment is shown, in which two adhesive walls 3 extend spirally along the height of the cylindrical filter element 1. The adhesive walls 3 extend in opposite circumferential directions and intersect. This is used in... Figure 20C The adhesive line 21 shown in the figure illustrates the adhesive wall in... Figure 20B The direction of the extracted portion XX marked in the text.

[0166] exist Figures 21A-21C The twelfth embodiment is shown, in which four adhesive walls 3 extend spirally along the height of the cylindrical filter element 1. Two adhesive walls 3 with opposite circumferential directions begin from common folded edges 16A and 16B. The adhesive walls 3 extend within the height range of the cylindrical filter element 1. The orientation of the adhesive walls 3 is as follows: Figure 21C The adhesive line 21 shown is illustrated here. The orientation of the adhesive wall 3 is thus restricted to... Figure 21B The portion marked in the figure is drawn on XXI.

[0167] The proposed adhesive joints in the pleated sections within the corresponding filter element allow for the stabilization of individual pleats and the entire pleat assembly or bellows in a manner that matches the appropriate installation and flow conditions. Simultaneously, the internal flow distribution can be altered through the flexible use of the adhesive walls. Overall, improved filtration performance can be achieved in the appropriate application.

Claims

1. A filter element for filtering a fluid, the filter element having a pleated assembly consisting of a filter medium folded in a zigzag and / or wave pattern, the filter medium having folded sections defined by folded edges, wherein at least two directly adjacent folded sections are connected to each other by adhesive portions along adhesive lines by means of adhesive material, wherein the adhesive lines extend at least partially obliquely relative to the folded edges between the two directly adjacent folded sections or offset along the folded edges between the two directly adjacent folded sections, wherein the filter element includes at least two adhesive portions along the respective adhesive lines, wherein the adhesive lines are spaced apart from each other and extend at least partially obliquely relative to the folded edges between the two directly adjacent folded sections or offset along the folded edges between the two directly adjacent folded sections, and wherein the spacing between adjacent adhesive lines varies along the folded edges between different folded edges.

2. The filter element according to claim 1, wherein the adhesive material is disposed on the folded section only on the inflow side or on the outflow side.

3. The filter element according to claim 1 or 2, wherein the adhesive material is continuously applied along the adhesive line between two fold edges defining at least one of the directly adjacent folded sections.

4. The filter element according to claim 1 or 2, wherein the adhesive lines of directly adjacent and opposite folded sections are aligned and opposite each other.

5. The filter element according to claim 1 or 2, wherein the adhesive portion is formed by two adhesive material coating portions joined together, wherein the two adhesive material coating portions are attached to directly adjacent and opposite folded sections.

6. The filter element according to claim 5, wherein the adhesive lines of directly adjacent and opposing folded sections are so obliquely opposed to each other that the two adhesive material coatings that are joined together are joined together at or over the two opposing folded sections over the entire length of the stretch.

7. The filter element according to claim 1 or 2, wherein the adhesive material is disposed on the outwardly pointing folded edges and between adjacent folded sections.

8. The filter element according to claim 1, wherein the filter element is used to filter combustion air in a motor vehicle and / or to filter the operating medium of the motor vehicle.

9. The filter element of claim 8, wherein the spacing between adjacent adhesive lines varies between adjacent folded edges along the folded edges.

10. The filter element according to claim 1 or 2, wherein the adhesive portion extends within a plurality of folded sections and folded edges interconnected by adhesive material, so as to form an adhesive wall in the fold assembly.

11. A filter element for filtering a fluid, the filter element having a pleated assembly having an inflow side and an outflow side, wherein the pleated assembly is formed by a zigzag-folded filter medium and has a height between the inflow side and the outflow side, wherein at least one adhesive wall formed of an adhesive material extends inside the pleated assembly, the adhesive wall being formed by adhesive portions of directly adjacent folded sections, and wherein the adhesive wall extends obliquely and / or flexibly along the direction of the height.

12. The filter element of claim 11, wherein the filter element has a width along the folded edge, a length extending transversely to the width, and a height, and the adhesive wall divides the pleat group into pleat group segments along the width.

13. The filter element according to claim 11 or 12, wherein the filter element is used to filter combustion air in a motor vehicle and / or to filter the operating medium of the motor vehicle.

14. The filter element according to claim 11 or 12, wherein the adhesive wall extends obliquely and / or flexibly along the direction of the length.

15. The filter element according to claim 11 or 12, wherein the height of the adhesive wall is at least partially less than the height of the filter element.

16. The filter element according to claim 11 or 12, wherein the adhesive wall extends between the folded edges of the inflow and outflow sides of the filter element or between the folded edges of the outflow and inflow sides of the filter element.

17. The filter element of claim 16, wherein the adhesive wall includes an inflow-side edge and an outflow-side edge, wherein the inflow-side edge defines an inflow surface of the filter element along the width, and the outflow-side edge defines an outflow surface of the filter element along the width.

18. The filter element of claim 16, wherein the inflow surface and the outflow surface of the filter element have different sizes and / or geometries.

19. The filter element according to claim 11 or 12, wherein the adhesive wall is configured as a flow guiding element within the pleated assembly.

20. The filter element of claim 11 or 12, wherein the adhesive wall separates the pure fluid region from the untreated fluid region.

21. The filter element according to claim 11 or 12, wherein the adhesive wall at least partially forms an angle between 5° and approximately 90° along the plane normal of the height and the inflow side or outflow side.

22. The filter element according to claim 11 or 12, wherein the adhesive wall is interrupted along the length of the filter element and / or spaced apart from the end side of the filter element.

23. The filter element according to claim 11 or 12, wherein the adhesive wall in the pleats has a closed shape.

24. The filter element according to claim 11 or 12, wherein the adhesive wall fluid-tightly seals the pleats on the sides.

25. The filter element according to claim 11 or 12, wherein a plurality of adhesive walls are provided.

26. The filter element of claim 25, wherein the width of the filter element is uniformly divided along the length by the spacing between the adhesive walls and the spacing between the adhesive walls and the sidewalls of the filter element.

27. The filter element according to claim 11 or 12, wherein the pleats are bent into a continuous bellows in a cylindrical shape.

28. The filter element according to claim 11 or 12, wherein the adhesive material comprises a solvent-containing wet adhesive, contact adhesive, dispersion adhesive, melt adhesive, plastisol, addition adhesive, condensation adhesive, polymeric adhesive, or pressure-sensitive adhesive.

29. The filter element of claim 16, wherein the adhesive wall connects the inflow side and the outflow side to each other.

30. The filter element of claim 21, wherein the adhesive wall at least partially forms an angle between 10° and 45° along the plane normal of the height and the inflow side or outflow side.

31. The filter element of claim 21, wherein the adhesive wall at least partially forms an angle between 10° and 30° along the height and the plane normal of the inflow side or outflow side.

32. The filter element of claim 25, wherein a plurality of intersecting or contacting adhesive walls are provided.

33. A method for manufacturing a filter element according to any one of the preceding claims, comprising the following steps: a. Provides flat filter media; b. Apply a sticky adhesive material along the pre-defined adhesive lines; c. Fold the filter medium along a pre-defined fold line to form folded edges between the folded sections, wherein adjacent folded sections are defined by the fold line; and d. Harden the adhesive material to form an adhesive portion between adjacent folded sections; The adhesive material is applied to the adhesive line such that the adhesive line extends at least partially at an angle relative to the fold line between the respective adjacent fold sections or extends offset along the fold line between the respective adjacent fold sections.

34. The method of claim 33, wherein the adhesive material is coated in a flowable state.

35. The method of claim 33 or 34, wherein the adhesive material is applied by means of a coating nozzle capable of moving along the fold line.

36. The method of claim 33 or 34, wherein the coating of the adhesive material is interrupted at least partially along the adhesive line.

37. The method of claim 33 or 34, wherein the adhesive material is applied simultaneously along different adhesive lines.

38. The method of claim 35, wherein the adhesive material is applied by means of a coating nozzle capable of moving along the fold line via continuous extrusion.

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