WO2019016228A1

WO2019016228A1 - Filter medium, folding pack, filter element, method for producing a filter medium and a folding pack and method for filtering a fluid

Info

Publication number: WO2019016228A1
Application number: PCT/EP2018/069430
Authority: WO
Inventors: Florentin Van Uffelen
Original assignee: Mann+Hummel Gmbh
Priority date: 2017-07-19
Filing date: 2018-07-17
Publication date: 2019-01-24
Also published as: DE102018117255A1

Abstract

The invention relates to a flat filter medium (1, 11, 21, 31) for filtering a liquid operating resource (F) of a motor vehicle, wherein the filter medium (1, 11, 21, 31) is foldable along specified fold lines (2, 2a, 2b) to form a folding pack (5, 15, 25); and the filter medium (1, 11, 21, 31) has, on at least one part of the fold lines (2, 2a, 2b), predefined sections (3, 13, 23) extending crosswise to the fold lines (2, 2a, 2b) having lower thickness (D).

Description

description

Filter media, pleat pack, filter element, method of making a filter medium and a pleat pack, and method of filtering a fluid

TECHNICAL FIELD The present invention relates to a filter medium, a pleat pack and a filter element for filtering a fluid, in particular an operating fluid for a motor vehicle, such. For example, oil. Furthermore, the invention relates to a method for producing a filter medium, a method for producing a fold pack and a method for filtering a fluid with a filter element. State of the art

Filters or filter elements typically include a filter medium for filtering a fluid. In addition to gases, a fluid can also be, for example, oil, fuel or another fluid. To form a filter element, the filter medium may be formed into a zigzag folded pleat pack having a plurality of pleats. The multiplicity of folds increase a filter area, thereby improving the filtering capability of the filter element. When increasing the number of folds, it can happen that adjacent folds, in particular in the region of fold edges, are close together. In this case, the entire outflowing fluid must flow through a constriction which is formed in the region of the folded edges between juxtaposed folds. It can happen that the outflowing fluid accumulates in the filter element.

The document EP 0 382 331 B1 discloses a filter insert made of a zigzag-folded filter material, wherein projections are formed in the filter material. These projections serve the distance assurance and stiffening of adjacent folds. The projections are formed by embossing the filter material, in which the entire filter material is deformed upstream and downstream. By this deformation, the filter material is stretched in the region of the projections, so that the side walls of the projections are formed thinner than the remaining filter material. For the necessary stabilization of the thin side walls and for the adhesion of projections of adjacent folds, an adhesive coating is applied to the projections and to their walls. Due to the adhesive coating are the Protrusions and their walls fluid-impermeable and reduce the effective filter area.

Disclosure of the invention

Against this background, the present invention has the object to provide an improved filter medium for filtering a fluid, which allows the fluid to flow through areas in which folds of the filter medium are close to each other. Other objects of the present invention are to provide an improved pleat pack, an improved filter element, an improved method of making a filter medium and a pleat pack, and an improved method of filtering a fluid with a filter element.

Accordingly, a flat filter medium for filtering a fluid, in particular a liquid such. B. a liquid operating means of a motor vehicle proposed. The filter medium is foldable along predetermined fold lines to form a fold pack. The filter medium has at least a portion of the fold lines transverse to the fold lines extending predetermined portions of lesser thickness.

According to one embodiment, a fold pack for a filter element for filtering a fluid is proposed. The fold pack is formed from the filter medium described above and below, which is folded in a zigzag along the fold lines, so that fold edges are formed at the fold lines. The term "filter medium" is understood to mean, in particular, a piece of filter material which can be folded into a fold pack and used in a filter element, in particular in an oil filter element The filter element itself can be used in passenger cars, trucks, construction machines, watercraft, rail vehicles, aircraft, etc. The motor vehicles or vehicles can be operated electrically and / or by means of fuel (in particular gasoline, diesel or natural gas).

In one embodiment, the filter medium is suitable for filtering liquids, in particular a urea solution, oil, gasoline, diesel or water. For example, oil is filtered with the filter medium for an internal combustion engine of a truck.

The filter medium is, for example, a filter paper, a filter fabric, a filter fabric or a filter fabric. For example, the filter medium is nonwoven material. Under a "Nonwoven material" is understood herein to mean a material comprising nonwoven fabric. A nonwoven fabric is an assembly of limited length fibers, filaments or cut yarns of any type and origin that have been somehow joined together to form a nonwoven (a fibrous layer, a batt) and interconnected in some manner. Alternatively, the filter material may also comprise paper or other suitable material for filtration. The filter medium is in particular single-layered.

In particular, the fold line is a virtual line along which it is intended to fold or buckle the filter medium to form the fold pack. The fold lines may run parallel to each other, wherein a distance between adjacent fold lines may be constant. In particular, the filter medium for forming the fold pack can be folded in a zigzag along the fold lines. The filter medium may be rectangular and have fold lines that are perpendicular to a longitudinal side of the filter medium. The fold lines are embossed in embodiments in the filter medium.

The predetermined sections are in particular location information for specific areas of the filter medium. In the predetermined portions, the thickness of the filter medium may be reduced or reduced compared to the thickness of the filter medium outside the predetermined portions. The predetermined sections may extend transversely, in particular perpendicularly, to the fold lines. Here, the predetermined portions may intersect the fold lines. There may also be a gap between the fold lines and the predetermined sections. The predetermined sections may be provided on all or even only part of the fold lines.

The predetermined sections can be flowed through in particular by the liquid operating medium to be filtered. In particular, a proportion of a flow area of the filter medium is thereby increased, and a filter capacity of the filter medium can be improved. Specifically, the predetermined portions are not covered with an adhesive layer or the like.

In embodiments, grooves, notches, recesses, grooves, grooves or the like are provided in the predetermined portions for reducing the thickness of the filter medium in the filter medium. In particular, the grooves have a groove bottom surface that is substantially parallel to a surface of the filter medium and opposite to the surface for reducing the thickness of the filter medium is set back. Further, the grooves may have groove side surfaces connecting the surface of the filter medium and the groove bottom surface of the groove. The groove side surfaces may extend perpendicular to the surface of the filter media and / or the groove bottom surface. A flat filter medium is understood in particular to mean a filter medium which extends in a plane. In particular, such a sheet-like filter medium has no projections and / or warping, which protrude from the plane. The flat filter medium is, for example, not a curved, corrugated or otherwise deformed prior to folding filter medium. Both sides of the sheet filter medium may extend parallel to one another in a respective plane.

The sheet-like filter medium may be flat on one side and on the other side the grooves, notches, recesses, grooves, grooves or the like, which cause the reduced thickness of the filter medium in the predetermined sections. In particular, the thickness of the filter medium in the predetermined portions is reduced only from one side of the filter medium. In other words, in reducing the thickness in the predetermined areas, only one of the sides of the filter medium can be deformed. The other side remains especially undeformed and flat.

The thickness of the filter medium may be half as large as the thickness of the filter medium outside the predetermined portions in the predetermined portions. To filter the fluid, the filter medium can be folded to the fold pack. In particular, the fold pack comprises fold edges which are created by folding the filter medium along the fold lines. The fold pack, sometimes called a bellows, can have a multiplicity of adjacent folds which are only slightly spaced apart from one another. In particular, a number of folds in a volume unit is maximized.

To fold the filter medium in a zigzag manner to form the fold pack serves, in particular, to increase a flow-through surface of the filter medium through which fluid flows when filtering. This can increase the filter capacity. Due to the close wrinkles, the fluid can often flow through the filter medium only poorly. The fluid also can not flow well past adjacent surfaces of adjacent pleats, thereby greatly reducing the filter capability of the filter media. In particular, the entire outflowing fluid must be passed through a bottleneck formed in the folding edges between adjacent folds of the fold pack. The constriction is especially the downstream side where the distance between adjacent folds is smallest. If the wrinkles are close together, it can happen that the escaping fluid builds up in the fold pack. Furthermore, a high pressure loss in the fluid can arise on the downstream side, in particular in the region of the constriction. In fact, the flow rate in the throat area increases, causing the increased pressure drop. The throat area may account for over 65%, and in particular over 80%, of the total pressure loss of the fluid as it passes through the pleat pack. The high pressure loss is undesirable because it leads to a reduced flow rate of the fluid and thus to a deteriorated filter capacity.

With the above-described filter medium, these problems can be solved because the thickness of the filter medium is reduced in the predetermined portions and thereby a distance between adjacent surfaces of adjacent folds in the predetermined portions can be increased. As a result, in particular the disadvantageous effect of the present constriction between adjacent folds can be reduced. The area through which the outflowing fluid can flow out of the fold pack can be increased. The fluid flowing out of the outflowing fluid surface is increased in the region of the folded edges, in particular by a cross section of the corresponding groove. Thereby, a pressure loss of the fluid flowing through can be reduced. The fluid can better flow out of the fold pack due to the increased area. In particular, in the case of a filter element formed into a round filter element, the fluid can flow out of the fold pack at an inner diameter of a star-shaped folded fold pack during a flow radially from outside to outside. In particular, channels for guiding the outflowing fluid are formed in the predetermined sections between the closely spaced or contiguous folds. Reducing the thickness of the filter medium in the predetermined sections serves to allow the fluid to flow through the fold pack even with very close wrinkles and to be filtered. Thus, the reduced thickness of the filter medium in the predetermined portions also serves to reduce a pressure loss and a speed drop or a change in velocity of the fluid as it flows through the filter medium, so that Filtering capacity of the Filtermediunns, the fold pack and / or the filter element can be increased. The filtering capability can be increased without having to disadvantageously reduce the number of wrinkles in the volume unit.

In addition, the flow-through surface of the filter medium, in particular in the region of the fold edges, is increased by the reduced thickness of the filter medium in the predetermined sections, because additional side walls are provided in the filter medium. In particular, the flow-through surface of the filter medium is increased relative to a surface which has no reduced thickness in predetermined sections. The flow-through surface of the filter medium is increased, for example, by a surface which corresponds to the previously described groove side surfaces. Due to the enlarged filter surface, the filter capacity of the filter medium can be increased.

Furthermore, all areas of the filter medium can be equally flown. As a result, all points of the filter medium can be uniformly polluted. In particular, the filter medium in the fold edges does not pollute faster than in other areas of the filter medium. The entire life of the filter element can thus be increased.

According to another embodiment, the filter medium has an inflow side and an outflow side, and the outflow side is set back in the predetermined sections in the direction of the inflow side.

When the filter medium is used as intended, the fluid in particular flows firstly through the inflow side and then the outflow side of the filter medium along a throughflow direction. The upstream side can be flown with a raw fluid to be filtered. From the downstream side, a filtered fluid can escape. The flow direction can run perpendicular to the fold lines or folding edges. The thickness of the filter medium corresponds to a distance between the inflow side and the outflow side.

The predetermined portions may be formed only on the downstream side. The thickness of the filter medium can be reduced in the predetermined portions only by a change in the geometry of the filter medium on the downstream side. For example, the above-described grooves, recesses, etc. formed in the predetermined portions in the filter medium may all be provided on the downstream side. Here, the inflow side can remain unchanged, especially be special without gutters, expansions, etc. The inflow side and / or outflow side is, for example, only except the predetermined sections, in particular flat and extends in a plane.

According to a further embodiment, the predetermined sections are strip-shaped. In a plan view of the filter medium, in particular on the inflow or outflow side, the predetermined portions may be strip-shaped and may have an elongated shape. For example, the predetermined portions extend as rectangles, ovals or diamonds across the fold lines along the filter medium. The various predetermined portions may have different sizes and shapes.

A length of the predetermined portions is, for example, half as large as a distance between adjacent fold lines.

According to a further embodiment, channels with a rectangular or semicircular cross-section are formed in the predetermined sections in the filter medium. The widths and heights of the channels are constant especially over their entire lengths. By means of the channels with a rectangular or semicircular cross section, a particularly large enlargement of the constriction through which the outflowing fluid flows can be achieved, whereby the outflowing fluid can be prevented from accumulating in the fold pack. Furthermore, the flow-through surface of the filter medium is increased by the channels.

According to a further embodiment, a plurality of the predetermined portions are provided on a same fold line, in which the thickness of the filter medium is reduced. The number of predetermined sections may depend on the size of the filter medium. According to a further embodiment, the predetermined sections extend over a plurality of directly adjacent fold lines of the filter medium. For example, the predetermined portions extend throughout an entire length of the filter medium, which length may be perpendicular to the fold lines.

According to a further embodiment, predetermined sections are provided only on every second folding line.

The filter medium may alternately have a fold line along a longitudinal axis of the filter medium, which runs in particular perpendicular to the fold lines, at which No predetermined portion is initially provided, and have a folding line on which at least one predetermined section is provided.

In zigzag-shaped folding of the filter medium into a fold pack, alternating inner and outer fold edges on the inflow side and alternating inner and outer fold edges on the outflow side can be formed, based on the flow direction.

According to a further embodiment, the predetermined portions are provided only in the region of the outer folding edges on the downstream side of the filter medium.

For example, if the predetermined portions exist only on every other fold line, the filter medium may be folded into the fold pack such that the channels formed in the predetermined portions are formed only at the outer fold edges on the downstream side. The fluid flowing through can exit the folded filter medium through the channels, even if the folds of the fold pack lie close together and a constriction is formed between adjacent folds. As a result, the pressure loss and / or the drop in velocity of the fluid which flows through the filter medium can be reduced when exiting the fold pack in the region of the constriction. The filter capacity of the filter medium can thus be increased.

According to another embodiment, a width of the predetermined portions in the region of the outer folding edges on the downstream side of the filter medium is greatest. The width of the predetermined portions may vary over the length of the predetermined portions. The width of the predetermined portion, in which the thickness of the filter medium is reduced, may be greatest at the fold edge itself or immediately adjacent to the fold edge. In the area of the fold edges, the channels formed between juxtaposed folds can be the largest, as a result of which the fluid can easily escape from the fold pack through the bottlenecks.

According to a further embodiment, the thickness of the filter medium in the region of the outer fold edges on the downstream side of the filter medium is the smallest. In the area of the outer folding edges on the downstream side, in particular on the folded edge itself, the thickness of the filter medium can be reduced the most. As a result, the greatest increase in the area of the bottleneck that can be flowed through by fluid can result in the area of the outer folding edges on the outflow side. According to a further embodiment, channels are formed in the fold pack in the region of the outer fold edges on the outflow side of the filter medium, in which the outflow side of the filter medium is set back towards the inflow side of the filter medium and which cause the surface of the outflow side to be larger by one channel side surface than the surface of the upstream side is.

The channels may be formed by opposing predetermined areas of juxtaposed folds. A channel is formed in particular by two opposing grooves. The channels are bounded by the groove side surfaces and by the groove bottom surfaces of the opposing channels. The channel side surface may include the groove bottom surfaces of the opposing grooves. The channels can be used for better flow through the filter medium with the fluid, especially in close-lying or superposed folds.

According to a further embodiment, the filter element is adapted to filter a liquid operating medium of a motor vehicle flowing along the direction of flow through the filter medium, wherein a pressure drop and / or a change in speed of the liquid operating medium when flowing through the filter medium in the region of the folded edges is reduced by the surface the outflow side of the fold pack is increased by the reduced thickness of the filter medium in the predetermined sections compared to a surface of the upstream side of the fold pack.

The upstream side of the fold pack, which in embodiments has no predetermined portions, in particular has a smaller flow-through surface than the downstream side with the predetermined sections. A distance between juxtaposed wrinkles can be increased based on the predetermined portions, whereby the fluid can flow better from the filter element. The described filter element can thus have an improved filter function.

In accordance with a further embodiment, the filter medium comprises a flat filter material and a grate element attached downstream of the filter material. The grid element has a deformation in the direction of the upstream side of the filter medium in the predetermined sections.

The filter material can be a filter paper, a filter fabric, a filter fabric or a filter fabric and have the properties already described above. The grid element or grid comprises, in particular, mutually parallel webs which are arranged such that intermediate spaces or continuous openings are formed between the webs. A height of the grid element may be twice the height of a web. For this purpose, the grid element may have two mutually superposed planes, wherein in the first plane first webs run parallel to one another and in the second plane second webs run parallel to one another. The webs can also be connected to each other at cross points. The webs can form a network structure. Four webs, which are arranged around an opening and connected to each other, can form a mesh. The grid is formed in particular of a plurality of meshes. An opening may limit an area of the filter material that is greater than 0.1, 0.2, 0.5, or 1 mm ² . The surfaces have, for example, a quadrangular geometry. The surfaces may be diamond-shaped, parallelogram-shaped or square-shaped. Alternatively, the surfaces may also be oval or round. The distance between two adjacent webs is called mesh size. The use of a grating element in a filter has the advantage that a compression of adjacent wrinkles is prevented. The lattice element prevents a flat "juxtaposition" or adhering of fold sections, since a spacing of the fold sections by the webs is ensured. "A drainage lattice can be used as the lattice element.

In particular, the grid element can guide the outflowing fluid along the webs. For this purpose, the grid element itself can form a plurality of channels between adjacent folds which are defined by adjoining webs. The deformation in the grid element serves to increase the distance between adjacent folds by forming further channels. The fluid is better able to flow out of the fold pack.

The grid element may also serve to support the filter material. The grid element may be attached to the filter material, in particular glued or welded. The grid element may be adhered to the filter material with a fusion adhesive bonding material. The grid element may be made of plastic.

The grating element may be deformed during manufacture in regions of the predetermined sections, for example with a thermal roller system. The grid element deformed in the predetermined sections can then be connected to the filter mat. pressed and fixed, whereby the Filtermate al is deformed in the areas of the predetermined sections. Alternatively, it is possible to first attach the grid element to the filter material, and then to deform the grid element together with the filter material in the predetermined sections. The deformation in the grid element may for example have a width of more than one mesh size, in particular between three and six mesh sizes, and a height of less than three mesh sizes, in particular of less than two mesh sizes have. The amount of deformation in the mesh member may be the size of a predetermined portion. In embodiments, the grid member has no deformation and is attached to the filter medium with the thickness reduced in the predetermined portions. In particular, the channels formed in the predetermined sections extend between the filter medium and the grid element. The grid element may in this case serve for spacing between adjacent folds, while the channels, in addition to the advantages already described, serve for a reduced coverage of the filter medium by the webs.

According to a further embodiment, the grid element has a plurality of mutually parallel webs with openings therebetween, wherein the webs are aligned parallel to the fold lines or inclined with respect to the fold lines by a predetermined angle.

According to a further embodiment, the predetermined portions are formed in or on the filter medium of reduced thickness by embossing, in particular with an embossing roller, ultrasonic treatment, compression of the filter medium and / or material removal. The imprint can be a thermal impression, which takes place on the basis of a heated embossing roller. For example, deformation may be impressed into an originally flat plastic grid element by heating it with the thermal roller system, deforming in areas of the predetermined sections, and cooling to solidify. A filter medium which does not comprise a grid element or a filter medium which is already fastened to the grid element can also be treated with such a thermal roller system in order to impress grooves in the predetermined sections of the filter medium. In the embossing, the filter medium is in particular compressed in the predetermined sections. It is also possible to compress the filter medium in the predetermined portions so as to reduce the thickness of the filter medium in the predetermined portions. For this purpose, for example, a roller can be used which presses on one side into the filter medium in the predetermined sections grooves. In a material removal also a predetermined amount of the sheet-like filter medium can be removed in the areas of the predetermined sections. This reduces the thickness of the filter medium in the predetermined portions.

According to a further embodiment, the thickness of the filter medium in the predetermined regions is reduced along a direction which is perpendicular to a plane in which the flat filter medium extends.

The plane in which the filter medium extends may be parallel to the inflow and / or outflow side of the filter medium. The filter medium may extend parallel to the plane in which the filter medium extends in the predetermined areas where it has a reduced thickness. In particular, not only the walls of deformation in the predetermined portion have a reduced thickness. Rather, the entire filter material in the predetermined section may have a reduced thickness.

According to a further embodiment, a method for producing a flat filter medium for filtering a liquid operating means of a motor vehicle, in particular for producing the filter medium described above and below, is proposed. The method comprises:

Providing a sheet-like filter medium foldable along fold lines to form a fold pack; and

Reducing the thickness of the filter medium in predetermined predetermined sections extending transversely to the fold lines on at least a part of the fold lines, wherein reducing the thickness of the filter medium comprises an embossing, in particular with an embossing roll, an ultrasonic treatment, a compression of the filter medium and / or a material removal ,

According to a further embodiment, a method for producing the fold pack described above and further comprises: folding the filter medium along the predetermined fold lines into a zigzag fold pack such that channels are formed in the region of the outer fold edges on the downstream side of the filter medium which the downstream side the Filtermediunns is set back towards the upstream side of the filter medium and which cause the surface of the downstream side to the channel side surface is greater than the surface of the upstream side.

The channels described above have in particular a rectangular, diamond-shaped or round cross-section.

According to a further embodiment, a method for filtering a liquid operating means of a motor vehicle with the filter element described above and below is proposed. The method of filtering includes:

Flowing the filter medium with the liquid resource to be filtered such that the filtered resource exits the fold pack through the channels.

Further possible implementations of the invention also include not explicitly mentioned combinations of features or embodiments described above or below with regard to the exemplary embodiments. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the filter medium, the fold pack, the filter element, and the method.

Further advantageous embodiments and aspects of the invention are the subject of the dependent claims and the embodiments described below. Furthermore, the invention will be explained in more detail by means of preferred embodiments with reference to the attached figures. Brief description of the drawings

It shows:

1 is a plan view of a filter medium according to a first embodiment;

Fig. 2 is a perspective view of a fold pack according to a first

embodiment; 3 is a perspective view of a detail of the fold pack according to the first embodiment;

FIG. 4a is a side view of the fold pack according to the first embodiment; FIG.

4b is a side view of a fold pack according to a second embodiment;

4c is a side view of a fold pack according to a third embodiment; 5 is a plan view of a filter medium according to a second embodiment; 6 is a plan view of a filter medium according to a third embodiment;

7a is a plan view of a filter medium according to a fourth embodiment;

FIG. 7b shows a section A - A from FIG. 7a; FIG.

FIG. 7c shows a section B-B from FIG. 7a; FIG. and FIG. 8 is a perspective view of a filter element according to a first embodiment

Embodiment.

In the figures, the same reference numerals designate the same or functionally identical elements, unless indicated otherwise.

EMBODIMENTS OF THE INVENTION FIG. 1 shows a plan view of a filter medium 1 according to a first embodiment for a filter medium. The filter medium 1 is a single-layered flat filter medium made of filter fleece. With the filter medium 1, for example, oil can be filtered, so that the filter medium 1 is suitable for use in an oil filter for an internal combustion engine of a truck. Shown are fold lines 2 of the filter medium 1, which run parallel to each other and to a side 24 of the filter medium 1 along an axis Y. A distance A between each two adjacent fold lines 2 is constant and is z. B. 2.5 cm along an axis. The filter medium 1 can be folded in a zigzag pattern along the folding lines 2 to form a fold pack. The fold lines 2 are virtual lines along the filter medium 1. This means that, in particular, they are not impressed in the filter medium 1.

The fold lines 2 are divided into first and second fold lines 2a, 2b. These alternate along a longitudinal axis L of the filter medium 1, which runs perpendicular to the fold lines 2, from. The first fold lines 2a are shown in long dashed lines, while the second fold lines 2b are shown in short dashed lines. Three predetermined sections 3 each extend transversely to the first fold lines 2a. The first fold lines 2a intersect the respective predetermined sections 3 in the center. In Fig. 1, only a single predetermined portion 3 is provided with a reference numeral.

The predetermined portions 3 are all formed identically. In the plan view, they are strip-shaped or rectangular and intersect the fold lines 2a. The predetermined sections 3 have a length I along the longitudinal axis L which is parallel to the axis X. runs, and a width b, which runs parallel to the fold lines 2 along the axis Y.

In the predetermined portion 3, a thickness of the filter medium 1 along an axis Z is reduced by 1 mm. Outside the predetermined portions 3, a thickness of the filter medium is 2.5 mm. Thus, the predetermined portions 3 form grooves 4 in the filter medium 1. The grooves 4 are provided in the filter medium 1 only on one side or surface 7 of the filter medium 1, which is described in FIG. 2 as a downstream side of the filter medium 1.

The filter medium 1 shown in FIG. 1 is produced by first providing the flat filter material or filter medium 1. Subsequently, the thickness of the filter medium 1 in the predetermined portions 3 is reduced. That is, the grooves 4 are impressed in the filter medium 1. For this purpose, the filter medium 1 is passed through a heated roller system and deformed in the predetermined sections 3 such that the thickness of the filter medium 1 is reduced there. Distances between adjacent embossed grooves 4 are constant here. The grooves 4 and the predetermined sections 3 are cut centrally through the virtual first fold lines 2a running perpendicular to the grooves 4. Parallel to the first fold lines 2a and between the grooves 4, the virtual second fold lines 2b extend.

The filter medium 1 shown in FIG. 1 is foldable zigzag along the fold lines 2a, 2b into a fold pack. Such a fold pack 5 is shown in perspective in FIG. In FIG. 2, only two folds 26 of the fold pack 5 are shown. The folds 26 are close to each other here. You can also lie directly next to each other. The fold pack 5 shown in FIG. 2 is shown schematically. Thus, the areas in which the filter medium 1 is folded are shown as surfaces for ease of illustration, although they are actually edges.

The fold pack 5 serves to filter raw fluid F, which may be oil, for example. For this purpose, the oil flows through the filter medium 1 along a flow direction R. The flow direction R extends in the region of the fold pack perpendicular to the folded edges 12a, 12b. The upstream side is denoted by 6, the outflow side by 7. The filtered oil flows along the flow direction R as pure fluid RF at the downstream side 7 of the filter medium 1 from. The folds 26 are arranged star-shaped in the fold pack 5 about a longitudinal axis parallel to the axis Y, wherein the flow through the folds from outside to inside, ie in the radial direction to the longitudinal axis, he follows. The folds may be formed as a star-shaped filter pack closed around 360 ° around the longitudinal axis.

The filter medium 1 is folded to form the fold pack 5 along the fold lines 2, so that the first fold lines 2a on the downstream side 7 fold edges 12a and the second fold lines 2b on the downstream side 7 form second fold edges 12b. The first and second fold edges 12a, 12b on the downstream side 7 extend parallel to each other along the axis Y. The first fold edges 12a are arranged along the flow direction R after the second fold edges 12b. The illustrated fold edges 12a and 12b are both located on the outflow side 7 of the filter element 1 and, referred to the flow direction R, referred to as outer and inner fold edges 12a, 12b.

When used as intended, the grooves 4 are downstream. In the folded filter medium 1, the grooves 4 are located at the outer folded edges 12a of the downstream side 7. For forming the grooves 4, the downstream side 7 is set back in the predetermined sections 3 in the direction of the inflow side 6. That is, a thickness D of the filter medium 1 in the predetermined portions 3 is reduced. As will be described in more detail below, a surface of the outflow side 7 or outflow side surface 17 is enlarged relative to a surface of the inflow side 6 or Anströmseitenober- surface 16 through the groove side surfaces.

Two opposing grooves 4 form between adjacent folds 26 channels 34. The channels 34 extend along the flow direction R and have a rectangular cross-section. The channels 34 serve to increase a distance between adjacent pleats 26 in the predetermined areas. In particular, a constriction 36, which is present downstream between adjacent folds 26, is increased. As a result, the oil can flow out of the fold pack 5 even in the very tight folds 26 along the arrow S2, without the oil accumulating in the folds 26. The individual grooves 4 prevent covering the outflow side 7 by the adjacent fold surfaces. The geometry of the grooves 4 will be described in more detail with reference to FIG. 3, which shows a perspective view of a detail of the fold pack 5 according to the first embodiment. An outer folded edge 12a of the downstream side 7 of the fold pack 5 is shown. The grooves 4 have the already described width b. In the grooves 4 is the downstream side 7 set back by a distance h in the direction of the inflow side 6 back. The thickness of the filter medium 1 is thus reduced in the predetermined portions 3 from the thickness D outside the predetermined portions 3 by the distance h, so that the thickness of the filter medium 1 in the predetermined portions 3 D - h.

The grooves 4 comprise a groove bottom surface 19 which corresponds to the outflow side 7 set back in the predetermined sections 3 in the direction of the inflow side 6. The groove bottom surface 19 extends parallel to the downstream side 7 of the fold pack 5 and parallel to the inflow side 6. The grooves 4 also include groove side surfaces 14 which extend perpendicular to the downstream side 7 and connect the groove bottom surface 19 with the downstream side 7. The downstream side surface 17 of the illustrated fold pack 5 is larger around the groove side surfaces 14 than the upstream side surface 16.

The grooves 4 and the channels 34 formed with the grooves 4 allow flow through the fold pack 5, even with closely spaced folds 26. The filtering capability of the fold pack 5 is thereby increased. Furthermore, a pressure loss of the oil flowing through the filter medium 1, in particular in the region of the folded edges 12a, is reduced. Overall, therefore, the filter capacity of the fold pack 5 is improved by means of the grooves 4. For producing the fold pack 5 shown in FIGS. 2 and 3, according to a method for producing a fold pack 5, the filter medium 1 is folded along the predetermined fold lines 2 to the zigzag fold pack 5 such that in the region of the outer fold edges 12a on the downstream side 7 of the filter medium 1 grooves 4 are formed, in which the outflow side 7 of the filter medium 1 is set back towards the upstream side 6 of the filter medium 1 and which cause the surface 17 of the downstream side 7 to the groove side surface 14 is greater than the surface 16 of the Inflow side 6 is.

4a shows a plan view of two adjacent outer fold edges 12a of the fold pack 5. The fold edges 12a and the folds 26 are in close proximity to each other, so that the filter medium surface, which is traversed by the oil, is particularly large. A distance between adjacent folds 26 varies along a radial direction of the fold pack 5. As shown by the arrows S1, the oil can flow only poorly due to the small distance between the adjacent folds 26. The channels 34 formed by opposing grooves 4 form spaces between the abutting outflow sides 7 of the adjacent folds 26, through which the oil can flow better. There is a flow S2 of the oil through the channels 34. As a result, a filtering capacity of the fold pack 5 is increased. A cross-section 8 of the channels 34 is shown striped in FIG. 4a. This cross section 8 is rectangular, wherein a length of the rectangular cross section 8 corresponds to the width b of the grooves 4 and a width of the rectangular cross section 8 corresponds to twice the distance h. The area through which the outflowing oil can flow out of the fold pack 5 downstream between adjacent folds 26 is increased by the cross section 8 of the channels 34. Through the channels 34, the downstream side surface 17 is increased.

FIG. 4b shows a plan view of two juxtaposed outer fold edges 12a of a fold pack 15 according to a second embodiment. The fold pack 15 differs in the cross-sectional shape of the channels 34 from the fold pack 5 according to the first embodiment. The groove side surfaces 14 are at an angle to the groove bottom surface 19. A cross section 18 of the channels 34 thus has the form of two adjacent isosceles trapezoids with a short side having the already defined length b and a long side having a length b + 2b 'has.

Also in the fold pack 15 according to the second embodiment, oil can be guided along the arrows S2 through the channels 34 and thus flow out of the fold pack 15 with closely spaced folds 26. The constriction 36 or the area through which the outflowing oil can flow out of the fold pack 15 downstream between adjacent folds 26 is increased by the cross section 18 of the channels 34. Thereby, an outflow of the outflowing oil from the fold pack 15 is simplified. Furthermore, the downstream side surface 17 is enlarged by means of the grooves 4. Overall, the filtering capacity of the fold pack 15 is improved by means of the channels 34.

FIG. 4c shows a plan view of two juxtaposed outer fold edges 12a of a fold pack 25 according to a third embodiment. The fold pack 25 differs in the cross-sectional shape of the channels 34 from the fold pack 5 according to the first embodiment of FIG. 4a. The cross section 28 of the channels 34 is circular. The channels 34 serve to allow oil to flow out of the fold pack 15 (S2), although the downstream sides 7 of adjacent folds 26 in the region of the outer fold edges 12a are very close to each other. The bottleneck 36 or the Area through which the outflowing oil can flow out of the fold pack 25 downstream between adjacent folds 26 is increased by the cross section 28 of the channels 34. Thereby, an outflow of the outflowing oil from the fold pack 25 is improved. The downstream side surface 17 is also enlarged by means of the grooves 4. Overall, the filtering capacity of the fold pack 25 is improved by means of the channels 34.

5 shows a plan view of a filter medium 1 1 according to a second embodiment. The filter medium 1 1 according to the second embodiment differs from the filter medium 1 according to the first embodiment in that the predetermined portions 13 in which the thickness of the filter medium 1 1 is reduced over the entire length of the filter medium 1 1 along the longitudinal axis L. extend. The predetermined portions 13 are parallel to each other and form channels 4. The production of the filter medium 1 1 takes place as the production of the filter medium 1 according to the first embodiment with the method for producing a filter medium.

The filter medium 1 1 according to the second embodiment is easy to manufacture because it does not have to pay attention to the position of the predetermined portions 3 along the longitudinal axis L. The position of the fold lines 2 is irrelevant in the filter medium 1 1 according to the second embodiment. A same filter medium 1 1 can be folded differently for use in different filter elements. The filter medium 1 1 according to the second embodiment is thus versatile.

The filter medium 11, like the filter medium 1 of the first embodiment, can be folded into a fold pack, not shown, by the method of making a fold pack with the roll system. When the folded pack is folded, the previously described channels are formed by opposing grooves 4, which allow the oil to flow through adjacent pleats.

FIG. 6 shows a plan view of a filter medium 21 according to a third embodiment. The filter medium 21 according to the third embodiment is different from the filter medium 1 according to the first embodiment in that the predetermined portions 23 in which the thickness of the filter medium 21 is reduced are not rectangular but are substantially diamond-shaped. The width b of the predetermined portions 23 is greatest at the first fold lines 2a. The width of the predetermined Sections 23 terminate with increasing distance from the first fold lines 2a. The production of the filter medium 21 is carried out as the production of the filter medium 1 according to the first embodiment by means of the method for producing a filter medium. The filter medium 21, like the filter medium 1 of the first embodiment, can be folded into a fold pack (not shown) by the method of manufacturing a fold pack with the roll system. Here, the previously described channels are formed by opposing grooves 4, which are funnel-shaped here. The channels allow the oil to flow through adjacent folds, increasing the filtration capacity of the filter medium.

FIG. 7 a shows a top view of a filter medium 31 according to a fourth embodiment. The filter medium 31 according to the fourth embodiment differs from the filter medium 1 according to the first embodiment in that the filter medium comprises a filter material 27 and a mesh member 9 superimposed. The filter material 27 is a filter fleece.

The grid element 9 is a plastic drainage grid and comprises first webs 29, which run parallel to one another and parallel to the folding lines 2a, 2b. The first webs 29 extend in a first plane of the drainage grid 9. Furthermore, the drainage grid 9 comprises second webs 30, which are inclined with respect to the first webs 29 and extend in a second plane of the drainage grid 9, which the first level lies. The second webs 30 are parallel to each other. Between the webs 29, 30 openings 35 are formed in the grid 9.

In Fig. 7a, a part of the filter medium 31 is shown, comprising the predetermined section 3 shown in dashed lines. In the predetermined section 3, the thickness of the filter medium 31 is reduced.

FIG. 7b shows a section along the line A - A from FIG. 7a. The line A - A intersects the filter medium 31 in the region of the predetermined portion 3 by a plurality of webs 29, 30. In the predetermined region 3, in which the thickness D of the filter medium 31 is reduced by the distance h, is the drainage grid 9 deformed by deformation 20.

The deformation 20 is obtained by passing the drainage grid 9 already connected to the filter material 27 through a roller system in which the Drainage grid 9 is heated and deformed. The roller system consists of two opposing rollers, between which the filter material 27 is guided to the drainage grid 9. On the side of the drainage grate 9, a heated roller is used, and on the side of the filter material 27, a cold roller is used. The heated roller leads to a softening of the plastic, which forms the drainage grid 9, which can be further deformed by means of the roller. The filter material 27 is fused with the deformation of the drainage grating 9 something. As a result, deformations 20 in the drainage grid 9 and in the filter material, which result in the outflow surface 7 being set back in the direction of the upstream side 6, arise in regions of the predetermined sections 3.

Fig. 7c shows a section along the line B - B of Fig. 7a. The line B - B intersects the filter medium 31 in the region of the predetermined section 3 along a first web 29.

FIG. 8 shows a perspective view of a filter element 22 according to a first embodiment, which filters oil of an internal combustion engine. The filter element 22 comprises folded pleat pack 5, which was described with reference to FIGS. 2 and 3. The fold pack 5 extends in a star shape between two end disks 32.

The folds 26 of the fold pack are close together. In the region of the fold edges 12a lying along a radial direction, the outflow sides 7 of juxtaposed folds 26 closely adjoin one another, so that the bottoms 36 (not shown) are formed between adjacent folds 26. The fold pack 5 comprises at the outflow side 7 in the region of the folded edges 12 a, not shown channels through which the oil can flow through the filter element 22. The filtering capability of the filter element 22 is thereby improved. When filtering oil with the filter element 22 to be filtered oil F flows through the filter medium 1 radially from outside to inside along the flow direction R. The filtered oil RF exits at the channel side surfaces of the channels 4, not shown, from the filter medium 1 and then flows through Starting pipe 33 from the filter element 22. The speed and pressure of the oil are hardly changed as it flows through the filter.

Although the present invention has been described with reference to embodiments, it is variously modifiable. The number of predetermined sections 3 and grooves 4 is variable. The shape of the predetermined sections 3, grooves 4 and channels 34 is not limited to the forms described; for example, the channels 34 may be funnel-shaped so as to be widest at the fold edges 12, 12a, 12b. Furthermore, the distance h may also vary within a same predetermined section. For producing the filter medium 1, 11, 21, 31, another method, for example a pressing method, can also be used. The grooves 4 need not be present on the downstream side 7, but may also be present on the inflow side 6. The shape of the cross section 8, 18, 28 of the channels 34 can also be modified; for example, the cross section may be triangular. The plurality of predetermined sections 3 and grooves 4 of a same filter medium need not all be identical. Instead of the star-shaped filter element 22 and a cuboid pleated filter element is conceivable.

Claims

claims

1. A flat filter medium (1, 11, 21, 31) for filtering a liquid operating medium (F) of a motor vehicle, wherein the filter medium (1, 11, 21, 31) for forming a fold pack (5, 15, 25) along predetermined fold lines (2, 2a, 2b) is foldable; and the filter medium (1, 11, 21, 31) has predetermined thickness (3, 13, 23) portions (3, 13, 23) extending at least part of the fold lines (2, 2a, 2b) transverse to the fold lines (2, 2a, 2b) ( D).

2. Filter medium according to claim 1, wherein the filter medium (1, 11, 21, 31) has an inflow side (6) and an outflow side (7), and the outflow side (7) in the predetermined sections (3, 13, 23) in Direction to the upstream side (6) is set back.

3. Filter medium according to claim 1 or 2, wherein the predetermined portions (3, 13, 23) are strip-shaped; and / or wherein in the predetermined portions (3, 13, 23) in the filter medium (1, 11, 21, 31) channels (4) having a rectangular or semicircular cross section (8, 18, 28) are formed.

4. Filter medium according to one of claims 1 to 3, wherein on a same fold line (2, 2a, 2b) a plurality of the predetermined portions (3, 13, 23) are provided, in which the thickness (D) of the filter medium (1, 11 , 21, 31).

5. Filter medium according to one of claims 1 to 4, wherein only on each second fold line (2, 2a, 2b) predetermined portions (3, 13, 23) are provided.

6. Filter medium according to one of claims 1 to 5, with a flat filter material (27) and a downstream of the filter material (27) mounted grid element (9), wherein the grid element (9) in the predetermined sections (3, 13, 23) a deformation (20) in the direction of the inflow side (6) of the filter medium (1, 11, 21, 31) has.

7. Filter mediunn according to claim 6, wherein the grid element (9) has a plurality of mutually parallel webs (29, 30) with intermediate openings, wherein the webs (29, 30) parallel to the fold lines (2, 2a, 2b) or with respect to the fold lines (2, 2a, 2b) are inclined by a predetermined angle.

8. Filter medium according to one of claims 1 to 7, wherein the predetermined sections (3, 13, 23) by embossing, in particular with an embossing roller, ultrasonic treatment, compression of the filter medium (1, 1 1, 21, 31) and / or Material removal are formed.

9. Filter medium according to one of claims 1 to 8, wherein the predetermined portions (3, 13, 23) fluidly permeable, in particular for the liquid operating medium (F) can be flowed through.

10. The filter medium according to any one of claims 1 to 9, wherein the thickness of the filter medium in the predetermined areas is reduced along a direction perpendicular to a plane in which the sheet-like filter medium extends.

1 1. A fold pack (5, 15, 25) for a filter element (22) for filtering a liquid operating means (F) of a motor vehicle with a filter medium (1, 1 1, 21, 31) according to one of claims 1 to 10, which extends along the folding lines ( 2, 2a, 2b) is folded in a zigzag shape, so that folding edges (12a, 12b) are formed on the fold lines (2, 2a, 2b).

12. fold pack according to claim 1 1, wherein on the outflow side (7) of the filter medium, based on a flow direction, alternately inner and outer fold edges (12 b, 12 a) are formed, wherein the predetermined portions (3, 13, 23) only in the area the outer folding edges (12a) on the downstream side (7) of the filter medium (1, 1 1, 21, 31) are provided, a width (b) of the predetermined sections (3, 13, 23) in the region of the outer Faltkanten (12 a) on the outflow side (7) of the filter medium (1, 11, 21, 31) is greatest, and / or the thickness (D) of the filter medium (1, 11, 21, 31) in the region of the outer fold edges ( 12a) on the outflow side (7) of the filter medium (1, 11, 21, 31) is the smallest.

13. fold pack according to claim 11 or 12, wherein in the region of the outer fold edges (12 a) on the outflow side (7) of the filter medium (1, 11, 21, 31) channels (4) are formed, in which the outflow side (7) of the Filter medium (1, 11, 21, 31) in the direction of the inflow side (6) of the filter medium (1, 11, 21, 31) set back and which cause a surface (17) of the downstream side (7) to a channel side surface larger than a surface (16) of the upstream side (6).

14. Filter element (22) for filtering a liquid operating means (F) of a motor vehicle with a fold pack (5, 15, 25) according to one of claims 11 to 13, wherein the

Filter element (22) is adapted to filter a along a flow direction (R) through the filter medium (1, 11, 21, 31) flowing liquid operating fluid (F) of a motor vehicle, wherein a pressure drop and / or a change in velocity of the liquid operating means (F ) is reduced by flowing through the filter medium (1, 11, 21, 31) in the region of the folded edges (12, 12a, 12b) in that the surface (17) of the outflow side (7) of the fold pack (5, 15, 25) the thickness (D) of the filter medium (1, 11, 21, 31) reduced in the predetermined sections (3, 13, 23) compared to a surface (16) of the upstream side (6) of the fold pack (5, 15, 25) without the thickness reduced in the predetermined portions (3, 13, 23).

15. A method for producing a flat filter medium (1, 11, 21, 31) for filtering a liquid operating means (F) of a motor vehicle, in particular for producing the filter medium (1, 11, 21, 31) according to one of claims 1 to 10, full:

Providing a flat filter medium (1, 11, 21, 31) foldable along fold lines (2, 2a, 2b) into a fold pack (5, 15, 25); and

Reducing the thickness (D) of the filter medium (1, 11, 21, 31) in predetermined sections (3, 13, 23) extending transversely to the folding lines (2, 2a, 2b) at at least one of Part of the fold lines (2, 2a, 2b), wherein reducing the thickness (D) of the filter medium (1, 11, 21, 31) an impression, in particular with an embossing roller, ultrasonic treatment, compression of the filter medium (1, 11, 21 , 31) and / or material removal.

16. A method for producing a fold pack (5, 15, 25) according to any one of claims 11 to 13, which comprises the method according to claim 15, and:

Folding the filter medium (1, 11, 21, 31) along the predetermined fold lines (2, 2a, 2b) into a zigzag-shaped fold pack (5, 15, 25) such that in the region of the outer fold edges (12a) on the downstream side (12) 7) of the filter medium (1, 11, 21, 31) channels (4) are formed, in which the outflow side (7) of the filter medium (1, 11, 21, 31) in the direction of the inflow side (6) of the filter medium (1, 11, 21, 31) is set back and which cause the surface of the downstream side (7) to the channel side surface is greater than the surface (16) of the upstream side (6).

17. A method of filtering a fluid resource (F) of a motor vehicle having a filter element (22) according to claim 14, comprising:

Flowing through the filter medium (1, 11, 21, 31) with the liquid operating medium (F) to be filtered such that the filtered operating medium (RF) exits the fold pack (5, 15, 25) through the channels (4).