Patent Application
20180361300
The invention concerns a filter bellows of a filter medium folded in a zigzag shape, as well as a filter element and a filter system, in particular for use as a flat air filter of an internal combustion engine, in particular of a motor vehicle.
End folds are the two outer folds at oppositely positioned end faces of the filter bellows of a filter element. End fold rims are the two free rims of the filter medium of which the filter bellows is formed and which extend along the end folds and delimit them at the end faces of the filter bellows. End edges of the filter bellows are the two other free rims of the filter bellows which extend between the end fold rims and are extending in accordance with the folding of the filter bellows. The fold edges are the edges along which the filter medium is folded. In case of an approximately parallelepipedal filter bellows folded in a zigzag shape and known on the market, the end fold rims and the fold edges are in general straight and extend parallel to each other. The end edges extend, viewed from the side looking onto the filter bellows, in a zigzag shape and perpendicular to the end fold rims and the fold edges. Prior to folding the filter medium, the end edges of the filter bellows, which later on will exhibit an imaginary parallelepipedal envelope, extend straight and parallel to each other. The imaginary envelope is defined by the end edges, the fold edges and end fold rims neighboring each other at a clean fluid side of the filter bellows, and the fold edges and end fold rims neighboring each other at a raw fluid side.
In case of filter bellows of flat filter elements, the filter media are not closed, i.e., the end folds, like the end edges, are not connected to each other. In contrast to this, in filter bellows of round filter elements the filter media are closed, i.e., their end folds are connected to each other. Filter bellows of flat filter elements in this context can be planar but can also comprises bends in different directions.
The prior art encompasses rectangular or trapezoidal filter bellows for flat filter elements or filter bellows with cut-off corners which are manufactured from an endlessly extending web of a filter medium. By laser cutting, for example, a plurality of geometries are conceivable which however entail partially a significant paper loss and thus waste of filter medium.
EP 1144083 B1 discloses a filter element in which a support passes through a passage in the filter element. In particular in case of a housing which is suitable for receiving flat filter elements, this constitutes a support between the oppositely positioned center points of the housing shells. These points are those with the greatest vibration amplitude in case of a component vibration. In this way, a reinforcement effect can be obtained by providing only one support. The passage is sealed off completely relative to the support by providing an additional seal so that a filter function without air leak can be ensured. The passage which is provided in this filter element is rectangular. It is oriented such that two of the oppositely positioned rectangle edges which are referred to as transverse edges extend parallel to the fold edges. The edges are formed by the fold edges themselves. Such a passage is introduced by waterjet cutting or by laser beam cutting into the already folded filter medium.
An object of the invention is to provide an areal filter bellows which enables stable installation in the housing of a filter system.
According to an aspect of the invention, the aforementioned object is solved by a filter bellows, in particular for an air filter system, of a filter medium folded in a zigzag shape, wherein a passage between a raw fluid-side surface and a clean fluid-side surface is formed with a raw fluid-side opening with raw fluid-side cross section and a clean fluid-side opening with a clean fluid-side cross section, wherein, in a projection of the openings onto each other, one of the cross sections, at least with sections thereof, is arranged outside of the other one of the cross sections.
Beneficial embodiments and advantages of the invention result from the additional claims, the description, and the drawing.
A filter bellows, in particular for an air filter system, of a filter medium folded in a zigzag shape is proposed, wherein fold edges extend respectively between oppositely positioned end edge faces formed of end edges, and wherein an end fold with a fold edge and an oppositely positioned free end fold rim is arranged at oppositely positioned end faces, respectively, and fold edges are positioned at a raw fluid-side surface in the installed state of use and at an oppositely positioned clean fluid-side surface in the installed state of use. In this context, a passage between the raw fluid-side surface and the clean fluid-side surface is formed with a raw fluid-side opening with a raw fluid-side cross section and a clean fluid-side opening with a clean fluid-side cross section, wherein, in a projection of the openings onto each other, one of the cross sections, at least with sections thereof, is arranged outside of the other one of the cross sections.
The filter bellows is in particular embodied as an areal filter bellows, also referred to as flat filter bellows. In case of a flat filter bellows, the fold edges are embodied straight and are producible, for example, by knife pleating or rotary pleating methods. Moreover, a flat filter bellows is not annularly closed, in contrast to a round filter bellows whose fold edges form annularly closed inflow and outflow surfaces, respectively, that can be flowed through radially.
According to the invention, the filter bellows, which can be embodied in particular as an areal filter bellows of a flat air filter, is provided with a passage that provides a continuous channel between the raw fluid-side surface and the clean fluid-side surface. This passage can be guided perpendicular to one of the surfaces through the filter bellows, but the passage can also be embodied to extend through the filter bellows at a slant relative to one of the two surfaces or to both surfaces. In this context, the raw fluid-side opening of the passage and the clean fluid-side opening can be of identical design. In the simplest case, both are of a circular shape so that a cylinder-shaped passage through the filter bellows is produced. The cross sections of the raw fluid-side opening and of the clean fluid-side opening however can also be embodied to have an oval, elliptical or angular shape or a mixed form thereof. Also, the raw fluid-side cross section and the clean fluid-side cross section can be differently configured, for example, one cross section can be round and the other cross section oval or angular. The passage can thus realize a transition from the raw fluid-side cross section to the clean fluid-side cross section. Also, one of the two cross sections can be larger than the other cross section so that a funnel-shaped passage is produced.
An advantage of a configuration of the raw fluid-side cross section and of the clean fluid-side cross section in different shapes resides in that, by means of a so-called poka-yoke effect, an improper installation of the filter bellows in the filter system is avoided. Also, a simpler installation in an adapted filter housing of the filter system can be achieved in this way.
According to an advantageous embodiment, the passage passes through the filter bellows from the raw fluid side to the clean fluid side. This means that the passage interrupts at least one raw fluid-side fold edge in the region of its raw fluid-side opening and interrupts at least one clean fluid-side fold edge in the region of its clean fluid-side opening. Preferably, in the region of the passage and its openings, at both sides a plurality of adjacently positioned folds and thus also adjacently positioned fold edges are interrupted at both sides.
According to an advantageous embodiment, the raw fluid-side opening in respect to its contour can be embodied to be different from the contour of the clean fluid-side opening. For example, one of the two openings can be embodied round or oval and the other one of the two openings can be embodied angular. In this way, a poka-yoke effect is advantageously achieved which enables an unambiguous installation of the filter bellows in a filter system. Also, the counter elements in the housing of the filter system can be correspondingly designed in a beneficial way for mounting.
According to an advantageous embodiment, the passage, at least in a section thereof, can have a conical extension between the raw fluid-side opening and the clean fluid-side opening. Such a conical extension which may be realized in that one of the two openings is larger than the other one, benefits the installation of the filter bellows, for example, by a facilitated insertion of a mounting element through the filter bellows in order to fasten the latter in a filter housing. In this way, an improved force introduction during installation in the filter housing is possible because a support of the mounting element can be designed stiffer. Mounting tolerances therefore play a less important role. Also, such an insertion aid which is beneficial for mounting the filter bellows can be realized in an advantageous way.
According to an advantageous embodiment, the passage can comprise, at least in a section thereof, a stepped extension of its wall. For example, for manufacturing technological reasons, it can be beneficial when the passage is embodied in a stepped shape. For example, in this way the filter bellows can be bored from the raw fluid-side surface to a certain depth of the filter bellows with a different cross section than from the surface at the clean fluid side. In this way, two partial passages with different cross sections then meet each other so that, as a whole, a stepped extension of the passage is provided. It can be beneficial in this context, for example, for reasons of manufacturing tolerances, that one of the cross sections in this context is greater than the other cross section
According to an advantageous embodiment, at least one of the end edge faces and/or one of the end faces can be subjected to a directional change. In such a configuration of the filter bellows, which deviates from a simple parallelepipedal shape, installation space specifications can be utilized beneficially because such a filter bellows can be virtually fitted to complex installation spaces. For example, in this way a parallelepipedal part of a filter bellows can be combined with a triangular or semi-circular part of a filter bellows.
According to an advantageous embodiment, the passage can be formed by laser cutting of the filter medium. By laser cutting, complex shape specifications can be fulfilled in a beneficial and inexpensive way. Also, by laser cutting the filter medium is affected only minimally because laser cutting represents a very gentle cutting method with which almost no mechanical pressure is applied onto the filter medium. Also, in this way advantageously slanted passages in pre-manufactured folded filter bellows can be introduced in a beneficial way because the geometry can be adjusted very flexibly by means of laser cutting.
According to an advantageous embodiment, the filter medium can comprise cellulose and/or can be made of cellulose. As filter media, beneficially nonwovens are employed. For this purpose, cellulose is useable in a very flexible way and is also of great advantage with regard to environmental concerns due to its easy degradability.
According to a further aspect, the invention concerns a filter element for filtering a fluid, with a filter bellows of a filter medium folded in a zigzag shape, wherein fold edges extend respectively between oppositely positioned end edge faces formed of end edges, and wherein an end fold with a fold edge and an oppositely positioned free end fold rim is arranged at oppositely positioned end faces, respectively, and fold edges are positioned at a raw fluid-side surface in the installed state of use and an oppositely positioned clean fluid-side surface in the installed state of use. In this context, a passage between the raw fluid-side surface and the clean fluid-side surface is formed with a raw fluid-side opening with a raw fluid-side cross section and a clean fluid-side opening with a clean fluid-side cross section, wherein, in a projection of the openings onto each other, at least one of the cross sections, at least with sections thereof, is arranged outside of the other one of the cross sections.
The filter element is in particular embodied as a flat filter element. In a flat filter element in accordance with the present invention, the fold edges of the filter bellows are embodied straight and are producible, for example, by knife pleating or rotary pleating methods. Moreover, a flat filter element is not annularly closed, in contrast to a round filter element in which fold edges of a round filter bellows form annularly closed inflow and outflow surfaces, respectively, that can be radially flowed through.
The afore described filter bellows can thus be used advantageously in a filter element that is exchangeably useable in a filter system. The filter bellows that is embodied in particular as an areal filter bellows of a flat air filter is provided with a passage that provides a continuous channel between the raw fluid-side surface and the clean fluid-side surface. This passage can extend perpendicular to one of the surfaces through the filter bellows but the passage can also be embodied to extend through the filter bellows at a slant relative to one of the two surfaces or to both surfaces. In this context, the raw fluid-side opening of the passage and the clean fluid-side opening can be of the same configuration. In the simplest case, the two are embodied circular so that a cylindrically shaped passage through the filter bellows is produced. The cross sections of the raw fluid-side opening and of the clean fluid-side opening can however also be embodied to have an oval, elliptical or angular shape or a mixed form thereof. Also, the raw fluid-side cross section and the clean fluid-side cross section can be differently configured, for example, one cross section round and the other cross section oval or angular. The passage can thus realize a transition from the raw fluid-side cross section to the clean fluid-side cross section. Also, one of the two cross sections can be larger than the other cross section so that a funnel-shaped passage is produced.
An advantage of an embodiment of the raw fluid-side cross section and the clean fluid-side cross section in different shapes resides in that an improper installation of the filter bellows in a filter system can be avoided due to a poka-yoke effect. Also, in this way a simpler installation in an adapted filter housing of the filter system can be achieved.
According to an advantageous embodiment, the filter bellows can comprise a circumferential seal at end edges and end fold rims of the raw fluid-side surface and/or of the clean fluid-side surface as well as at the raw fluid-side opening of the passage and/or of the clean fluid-side opening of the passage. In this way, an effective sealing action of the filter element when installed in a filter housing, and thus the separation between a raw fluid side and a clean fluid side of the filter system, is possible. The efficiency of a filter system depends substantially on a reliable separation of raw fluid side from the clean fluid side. Primarily, the sealing action in use in a motor vehicle must function under very different environmental conditions entailing great temperature fluctuations, moisture, vibrations and the like. Leakage of the filter system between the raw fluid side and the clean fluid side can thus be avoided quite reliably.
As a circumferential seal, a seal which is congruently foamed onto the filter bellows, for example, of a PUR foam, can therefore be provided particularly advantageously. In this way, it is possible to produce a connection as strong as possible between the filter bellows and the seal which is also substantially permanently seal-tight and in this way ensures the efficiency of the filter system at least for the service life of the filter element. As a material for the foamed-on seal, for example, polyurethane foams are conceivable which enable a very flexible shaping and, on the other hand, a strong and permanent connection. Also, the processing steps can be designed such that conventional filter media can be foamed about with them in a compatible way and no degradations at the interfaces between plastic material and filter medium can occur. In this way, also extensive design variations of the shape of the filter element can be achieved.
Advantageously, the circumferentially extending seal can be arranged at end edges and end fold rims of the filter bellows as well as at the raw fluid-side opening of the passage and/or at the clean fluid-side opening of the passage. In this way, it is possible to insert the filter element into the housing bottom part of a filter housing so that the raw fluid side of the filter element terminates with a housing edge and the housing top part can be placed on top. In this way, the raw fluid side of the filter element can be sealed beneficially from the clean fluid side of the filter element. Also, when exchanging the filter element, a contamination of the clean fluid side of the filter system can thus be avoided. According to an advantageous embodiment, at least one of the end edge faces and/or one of the end faces can be subjected to a directional change. In such an embodiment of the filter element, which deviates from a simple parallelepipedal shape, installation space specifications can be utilized beneficially because such a filter element can be essentially fitted into complex installation spaces. For example, in this context a parallelepipedal part of a filter bellows can be combined with a triangular or semi-circular part of a filter bellows to a filter element which is beneficial regarding the installation space.
According to a further aspect, the invention concerns the use of the filter system as a flat air filter, in particular as a flat air filter of an internal combustion engine, in particular of a motor vehicle. Conceivable is also the use for other flowing media, for example, oil, fuel, urea, and the like.
According to a further aspect, the invention concerns a filter system with a filter element wherein the filter element is exchangeably arranged in a filter housing that comprises at least a housing bottom part and a housing top part which are connected fluid-tightly and detachably to each other and wherein the filter element fluid-tightly separates a raw fluid side from a clean fluid side of the filter system. By use of a filter element with a filter bellows according to the invention with a passage that provides a raw fluid-side opening and a clean fluid-side opening, wherein the passage can extend at a slant relative to the raw fluid-side surface and/or to the clean fluid-side surfaces of the filter bellows, a reliable installation of the filter element in the filter housing can be ensured. An advantage of a configuration of the raw fluid-side cross section and the clean fluid-side cross section of the passage in particular in different shapes resides in that an improper installation of the filter bellows in a filter system can be avoided by means of a poka-yoke effect. Also, in this way a simpler installation in an adapted filter housing of the filter system can be achieved.
According to an advantageous embodiment, a reinforcement center support supported at the housing bottom part and/or housing top part can be arranged in the passage when the filter element is installed. This reinforcement center support, which can be realized, for example, as a tie bar in the filter housing, permits a reliable installation by means of an additional support of the filter bellows and thus of the filter element in its surface at the filter housing. In this way, also possible vibrations, which may occur, for example, in operation in a motor vehicle, can be kept away from the filter element. Vibrations of the filter bellows can thus be suppressed effectively, which favors a long service life of the filter element.
According to an advantageous embodiment, the passage can be embodied as a clean air outlet. By means of such a flow opening in the filter bellows of a filter system, the filtered fluid, for example, air, can be returned in a targeted fashion. Fluid inlets and outlets of the filter system can thus be designed in a flexible way. In particular by a slanted passage relative to one or both surfaces of the filter bellows, it is possible to beneficially design a flow guidance of the fluid to be filtered into a calm flow region of the filter system.
Further advantages result from the following drawing description. In the drawings, embodiments of the invention are illustrated. The drawings, the description, and the claims contain numerous features in combination. A person of skill in the art will also expediently consider the features individually and combine them to meaningful additional combinations.
In the Figures, same or same-type components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting.
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The passage 50 can be formed, for example, by laser cutting the filter medium 14. The filter medium 14 comprises, for example, cellulose and/or is made of cellulose. The end edge face 20a is subjected to a directional change, i.e., deviates from a purely parallelepipedal shape so that the filter bellows 12 can be fitted into an installation space designed accordingly. The folds 34 of the filter medium 14 are illustrated only in one part of the filter bellows 12; the remainder of the filter bellows 12 that also comprises the filter medium 14 folded in a zigzag shape is illustrated only purely schematically.
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The construction of the reinforcement center support 80, comprised of hollow socket 82 and threaded socket 84, can be seen in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2015 016 237.3 | Dec 2015 | DE | national |
This application is a continuation application of international application No. PCT/EP2016/078846 having an international filing date of 25 Nov. 2016 and designating the United States, the international application claiming a priority date of 16 Dec. 2015 based on prior filed German patent application No. 10 2015 016 237.3, the entire contents of the aforesaid international application and the aforesaid German patent application being incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2016/078846 | Nov 2016 | US |
| Child | 16007328 | US |
