DE102013002213A1 - Manufacturing multi-dimensionally structured or knitted material web that is used in e.g. filter unit, comprises pressing brush-like elements against material web, and partially supporting material web by linear support elements - Google Patents

Abstract

The method comprises: pressing brush-like elements or soft pressure elements against a knitted or crocheted material web (1) and arranging 3-ply stitch rows and 2-ply yarns assemblies between the pressure elements and the material web before the pressing process; partially supporting the material web by linear support elements (5) arranged on a roller i.e. elastic pressure roller (3), and pushing an active medium against the material web to form a multi-dimensional structure; and forming uniform mesh cross-section in the material web for guiding a fluid medium. The method comprises: pressing brush-like elements or soft pressure elements against a knitted or crocheted material web (1) and arranging 3-ply stitch rows and 2-ply yarns assemblies between the pressure elements and the material web before the pressing process, where the 2-ply yarns assemblies have a height smaller than that of the 3-ply stitch rows having constant thickness, the brush-like elements or the soft pressure elements are moved towards each other, and the distance between the 3-ply stitch rows is reduced; partially supporting the material web by linear support elements (5) arranged on a roller i.e. elastic pressure roller (3), and pushing an active medium against the material web to form a multi-dimensional structure as bulge or three-dimensional wavy structure using an additional elastic sheet, where the elastic sheet is guided between the support elements and the material web, and the material web is stiffened; and forming uniform mesh cross-section in the material web for guiding a fluid medium. The brush-like elements are formed as pins that are sequentially arranged behind another on narrow strips, where ends of the strips are grooved. The strips are guided using rotatable rails. The soft-pressure elements are tiered with each other as resilient nub elements. An independent claim is included for a method for manufacturing a multi-dimensional structured woven web.

Description

The invention relates to a method for producing a structured material web from knitted, knitted or woven threads, in particular fine wires made of noble metal or stainless steel, which is equipped with multidimensional stiffening structures, for the flow of fluid media and use thereof, in particular as catalyst networks or as filtering means.

State of the art

In chemical reaction engineering, for example, in the ammonia oxidation for the production of nitric acid or hydrocyanic acid with the aid of catalyst networks of the noble metal alloys platinum / rhodium or platinum / rhodiuni / palladium with increased surface area, woven or knitted or knitted fabrics of fine metal wires used. In the mechanical separation technique of filtration for the separation of particles from gaseous or liquid media filter media from threads, such as fine metal wires, in particular made of stainless steel, are used. In the flow through this network or mesh-like structure of fluid media, the arrangement of the threads to each other and the stability of particular importance.

Previously, catalyst nets were often used from woven precious metal wires. However, since only a 2-ply net structure is formed in weaving by cross-superimposed metal wires, with the metal wires touching in a wave, when gas flows through compared to the available surface (for the catalytic reaction), a relatively large resistance produced, which can endanger the dimensional stability or strength of the catalyst network. In the case of a knitted fabric, for example, a loop structure results in an at least 3-layered mesh structure which forms a relatively larger free surface compared to the fabric with the same weight per unit area. Knitted fabrics and knits, due to their multi-ply mesh structure, allow improved flow through the catalytic reaction due to their larger specific surface area. In the WO 92102301 For example, a knit fabric and a method for producing noble metal-containing catalyst networks formed by means of an open-knit tricot knit warp knitting machine are described. However, this knit behaves like a relatively loose net with poor dimensional stability and easier displaceability of the wires to each other. This disadvantage is due to that in the DE 4300791 A1 described Gewirk and a process for its production by means of closed-formed mesh overcome. In this case, an at least 3-layered mesh structure with a high specific surface area, based on the volume occupied by the knitted fabric, is produced. In this case, the knitted fabric is given a good mechanical stability, if - at least one of the knit forming stitch bonds - the backing of the precious metal-containing wires over at least 3 needle pitches. As a result, the knitted fabric has at least 14 stitches per inch, whereby at least one of the knit stitches forming the knitted fabric is covered by the wires containing noble metal over at least three stitch spacings ( DE 4300791 A1 ). An example of a meshed net mesh corresponds to the "warp knitting" described in Prospectus of Heraeus, "Ammonia Oxidation Catalysts from Heraeus", DF Lupton et al., Page 09 , A knitted fabric, however, still needs to be improved, since the mesh cross sections for the flow through the fine catalyst net (also referred to below as free mesh or net cross section or flow cross section) can still be significantly uneven. In the area of the interlinked thread loops of the wires in the courses, the clear distance of the wires from each other is relatively small, and in the area between the courses, the clear distance between the wires is comparatively large.

Also known are undulatory catalyst networks of noble metal alloys, including palladium, which, as a system of recovery networks, largely recover the platinum lost in the ammonia combustion and possibly rhodium. With the help of a wave-shaped arrangement of the catalyst networks can be achieved that the reaction performance is improved due to greater specific surface area in their flow around or the flow pressure loss based on the reaction power comparatively lower. However, these wavy (with gentle curves of a sine or cosine curve) arranged catalyst networks are still in need of improvement for two reasons: First, it is a disadvantage that in a wavy arrangement of the catalyst networks, the larger specific surface area occurs only in the areas where the corrugated surface is inclined with respect to the inflow direction of the fluid medium, in other words in the region of the corrugation flanks. The sinusoidal or cosinusoidal crests and valleys, where the fluid medium flows quasi-perpendicularly through the catalyst networks, contribute only insignificantly to the enlargement of a larger specific surface area. Secondly, it is disadvantageous that a corrugated arrangement of the catalyst nets, similar to a corrugated sheet metal or parallel beads, stiffening only in a single direction; perpendicular to this, the wave-shaped catalyst network remains very flexible and therefore shifts slightly.

The free cross section of the fine mesh can be narrowed with increasing chemical service life, since the oxidized, porous noble metal layers of the wires occupy a larger volume than the pure noble metal. Since the volume flow rate of the fluid flowing through would decrease disproportionately at the catalyst net with a reduced mesh cross section and at the same pressure difference, one would have to increase the pressure difference at the catalyst network accordingly in order to be able to maintain an approximately constant volume throughput. This could adversely affect the strength of the fine catalyst networks and the stability of their multilayer, wavy configuration. It would therefore be desirable if catalyst networks could have a high dimensional stability in several directions.

In filter systems, nets made of fine metal wires or textile fibers are used as filter media to separate particles from gaseous or liquid media. Here, too, fine meshes with small and preferably equal, free mesh cross-sections, sufficient strength of the wires or fibers and a good stiffness of the meshes, in particular an all-round flexural rigidity, are desirable. In this case, a high degree of separation of the particles from the liquid or gaseous medium is to be achieved. With increasing deposition of the separated particles on the filter means increasing pressure or acceleration forces are required in order to press the liquid or gaseous medium through the mesh of the filter medium and filter cake if necessary.

In the WO 98/40910 and in the US 2005/02 52 182 A1 are ribbed or corrugated filter means described, which indeed have a stiffening, but in which the stiffening is effective only in the direction of their profiling. Perpendicular to the profiling, the ribbed or corrugated filter medium remains flexible.

In the DE 10 2006 062 189 B4 For example, a method of making a structured web for fluid media flow, a structured web, and a use thereof is described. Here, a material web is equipped with three-dimensional facet-shaped structures, which - similar to pyramid tips - each have evenly spatially inclined surfaces and a highest-lying star point. The three-dimensional facet-shaped structures themselves are from the DE 10 2004 1555 B4 known. In the area of this designated star point, the structure is provided with a hole (claim 1 of DE 10 2006 062 189 B4 ), wherein the pyramid tips in the star points can be formed further increased (claim 4 of DE 10 2006 062 189 B4 ). In this way it can be achieved that a three-dimensional facet-shaped structured material web forms a continuous flow gradient for a fluid medium towards the flood holes of the structures. In the DE 10 2006 062 189 B4 Furthermore, a three-dimensional wavy structured material web is described, wherein the dome is provided with an excellent hole (claim 19 of DE 10 2006 062 189 B4 ). The use of a three-dimensionally facet-shaped or three-dimensionally wave-shaped structured material web is known for the drum of a laundry treatment machine or for a distributor element, in particular for the production of glass fiber, or for a distribution or metering device, in particular for fluid media (claims 16, 17, 18, 33, 34, 35 of the DE 10 2006 062 189 B4 ). Out 7 and 8th of the DE 10 2006 062 189 B4 Further, a bulge-structured filter medium is known, which may consist of mesh or woven fabric of materials such as textiles or inorganic fiber fabric. However, these are still in need of improvement in order to produce a much smaller and at the same time approximately uniform free mesh or mesh cross section for the media flowing through it with sufficient strength and high multi-dimensional flexural stiffness of the mesh fabric than before.

task

The invention is based on the object, a method for producing a multi-dimensionally structured material web of knitted, knitted or woven threads, such as wires, in particular of precious metal and stainless steel, or fibers, which are flowed through by a gaseous or liquid medium, in particular for catalyst Nets made of precious metal or for filter media, in particular made of stainless steel wires or fibers, further develop in such a way that the free network cross section for the medium flowing through is reduced and formed substantially uniformly, a high multi-dimensional rigidity, in particular bending stiffness, the material web is achieved and the material the threads of the material web is particularly spared. These improvements should be carried out with the least possible design effort.

This object is achieved by a method according to the invention for producing a knitted or knitted, three-dimensionally structured, such as bulge-shaped or three-dimensionally wavy structured material web according to independent claim 1, by a method for producing a woven, three-dimensionally structured, such as beul - or arch-shaped or three-dimensional wave-structured, web according to the independent claim 5 and by a use the structured material webs as a catalyst network, in particular of platinum-rhodium or platinum-rhodium-palladium, or as a filter medium in claim 11, achieved. Advantageous embodiments of the invention are subject of the dependent claims 2 to 4 and 6 to 10.

This complex task is solved by the method according to the invention in that a conventional, mesh or mesh-shaped material web as a knitted fabric or fabric of threads, such as wires or fibers, is transformed in such a way that the distance of the threads to each other, in other words, the net cross-section is formed reduced by a substantially bending deformation of the threads, and then this arrangement of threads is structured three-dimensionally by a particularly gentle material forming and so the net-shaped web is multi-dimensionally stiffened, and at all locations of the web a steady Inclination is formed in the projection direction of an incoming fluid medium, whereby the flow cross-section is reduced in the projection direction and the flow around the threads of the material web can be intensified.

According to the process of the invention, catalyst networks may be prepared from fine precious metal wires, particularly platinum / rhodium or platinum / rhodium / palladium noble metal alloys, such as for ammonia oxidation or hydrogen cyanide production for improved chemical reaction performance.

By the method according to the invention, in a similar manner, a filter medium, in particular of stainless steel wires or textile fibers, can bring about an improved mechanical separation of particles from gaseous or liquid fluids.

In the following, the individual aspects are explained in more detail by the method according to the invention:
A smaller and rather uniform spacing of threads, such as wires or fibers, from each other can be achieved in a net or mesh-shaped material web by forming an approximately parallelogram-shaped net arrangement in a primary production step from a conventional approximately rectangular net arrangement, the edge lengths of the Threads of a single mesh grid are virtually unchanged. This is done by a particularly material gentle bending forming the threads, wherein by reshaping the rectangular arrangement in a parallelogram arrangement, a reduced distance of the threads to each other and thus a smaller flow cross-section is formed. This is due to geometrical reasons, since with the same edge lengths of a single net grid, a parallelogram always occupies a smaller area than a rectangle. This will be discussed in more detail later, since woven and knitted or knitted net or webs behave quite differently. It is essential that after the above-mentioned bending deformation of the fibers due to their elastic material behavior, the approximately parallele-shaped threads of the nets can spring back in part (tends back to the rectangular arrangement of the fibers). In order to prevent this, according to the invention, in a coupled or integrated, secondary production step, the parallelogram network arrangement of the fibers is fixed with the aid of a material-saving, multi-dimensional structuring method and at the same time provided with a high bending stiffness on all sides. In the case of very flexible threads in the largely plastic material behavior, where no or only an insignificant springback occurs, one could do without a fixation of approximately parallelogram formed arrangement of the threads.

In the processes described here of a reshaping of the threads in order to reduce the distances between the threads to each other and stiffening the same knitted fabrics or knitted fabrics behave quite differently than tissue. The reason for this is the different geometric arrangement of the threads in a net or mesh-shaped material web. Before the solution is described in detail according to the task, the terms tissue, knitted fabric and knitted fabric are briefly described and delimited from one another: Tissues are composed of separate threads, such as wires or fibers, which are arranged crosswise and undulating to each other Touch points have twice the thread thickness and so give a 2-ply sheet. Knitted fabrics are made of thread systems by a spatial stitch formation on a knitting machine industrially produced fabrics. Here are formed by interlocking thread loops spatial meshes, and thus creates a minimum of 3-layer mesh structure. When knitting or crocheting one stitch is made next to the other with the thread running horizontally along a course of stitches.

According to one aspect of the invention will now be explained in more detail, as in a knitted or knitted fabric, the distance of the threads, such as wires or fibers is formed reduced to each other and thereby a smaller and substantially uniform mesh or mesh cross-section can be generated. By the words "substantially uniform mesh or mesh cross-section" is to be expressed that due to the spatial mesh arrangement described above, wherein the thread loops can be arranged complex, only conditionally of a uniform network cross-section, such as in a woven material web, can be spoken.

The material web is fixed in a primary production step in the region of the at least 3-ply courses by pressing or pressing elements, and then these elements together with the fixed material web to move towards each other, whereby the clear distance between the at least 3-ply courses of the web is formed reduced. In particular, the following two variants can be used for this purpose:
In the first variant partially or pointwise attacking elements, analogous to a brush, but with a narrow row of fine pins, used, which are arranged as follows: Fine, stiff pins are each arranged in a row in separate, parallel sliding strips. These pins with their pointed end are preferably pressed in the region of the at least 3-layer mesh arrangement between the threads in order to fix the material web. Here are the threads, such as wires or fibers, multi-layered one above the other and behave more stable than in the region of the 2-layer thread arrangement in between. The thickness, ie the height in the vertical direction, the at least 3-layer mesh arrangement is not or only slightly changed. Then, the strips provided with the pins are moved together with the fixed material web parallel to each other and moved toward each other. The successive Zubewegen takes place quasi by itself, which can be explained as follows: The forces transferred from the pins on the web substantially the threads in the region of the 2-layer thread arrangement (between the at least 3-layer rows of stitches) are bent obliquely and into a brought about parallelogram network arrangement. Since the formed parallelogram of a single mesh grid occupies a smaller area with unchanged edge length of the threads than the original rectangle, the net or mesh cross-section is formed reduced. In the region of the at least three-layered threads, a geometric rearrangement into an approximately parallelogram-shaped shape is not necessary since, owing to the at least three-layer, spatial, mesh-like thread arrangement, the free cross section for a fluid medium flowing through is low anyway.

After this substantially bending deformation of the threads, a springback of the threads and thus an undesirable regression towards the rectangular, d. H. larger, mesh size - go. Therefore, in a subsequent or integrated production step (secondary production step), the approximately parallelogram-shaped arrangements of the threads are fixed by a multi-dimensional structuring and at the same time stiffened multidimensionally. In this case, the three-dimensional structuring takes place particularly gently, and the fibers are not or only slightly compressed. This material-saving, multi-dimensional structuring will be described in more detail later.

In a further variant according to the invention, soft partial printing elements are used, which from above, d. H. perpendicular to the material web, press substantially against the - at least 3-ply rows of stitches in comparison to the 2-ply rows of threads - and then perpendicularly thereto, d. H. parallel to the material web to be moved against each other. The minimum of 3-ply courses are not or only slightly compressed. As a result, the two-ply rows of threads of the material web, which are located between the at least three-ply rows of stitches, are pushed together in part, ie. H. almost squashed. In this way, the distance of the threads are reduced to each other and the network cross-section formed reduced in particular in the region of the 2-ply rows of threads. In a very simple embodiment, for example, in a material web with small geometric dimensions, the fingertips of a left and right hand can be used as soft printing elements. Here, the fingertips of one hand and the fingertips of the other hand are pressed from above against the web, which lies on a smooth table, and then moved against each other.

According to a further aspect of the invention, it will now be explained how, in the case of a woven fabric, the spacing of the threads, such as wires or fibers, from one another is reduced and a small net cross section of the woven material web can thereby be produced. This is easier to do with a fabric than with a knit fabric because there are no stitches on a fabric whose threads could contract. A weave behaves more like a planar, flat structure, with its woven, ie flat and wavy, threads touching each other at their points of intersection and moving like hinges. Of course, there are also minor bending deformations, as the threads are not straight but somewhat wavy, but can be neglected in good approximation. With such a fabric, it is now possible to reduce the net cross-section comparatively simply by forming a parallelogram-shaped thread arrangement from a rectangular one. According to one aspect of the method according to the invention, this can be done by a shear deformation of the woven material web, for example by means of laterally engaging rails. This happens in particular on a pre-curved, for example cylindrically pre-curved, material web. This is possible avoid that in the shear deformation, similar to the torsion of a thin-walled cylinder - due to under 45 ° to the direction of the web thereby adjusting pressure forces - form themselves undesirable wrinkles or waves in the web. Due to the pre-curvature of the material web leads to a stabilization and makes the latter less sensitive to the undesirable wrinkles or waves.

Instead of the laterally engaging rails, it is also possible to use simple tension elements which engage diagonally on the rectangular, woven material web. In order to avoid the above-mentioned undesirable wrinkling or wave formation, the woven material web can also be cylindrically pre-curved. This is done, for example, by resting the material web on a smooth roller, preferably on the same elastomeric pressure roller, which is used anyway for the production step of the multi-dimensional structuring of the material web (secondary production step).

In the following, the multi-dimensional stiffening is explained in more detail by a material-friendly structuring of the knitted, knitted or woven material web, which was equipped in the primary production step with a small network cross-section. Insights from known multi-dimensional structuring methods are used and the latter developed further.

The known beul- or vault structured and three-dimensional wavy structured material webs are thin-walled boards or coils, in particular of homogeneous materials, such as metal and plastic. Or it is paper, cardboard and fiber-reinforced plastics, which are not homogeneous but have no cavities. Therefore, the specific volume of the material is virtually unchanged during their transformation, as in the known bulge or vault structured and three-dimensional wave-like structuring.

In contrast, the forming mesh-like webs, as much more difficult, since the looping can cause entangling in the cavities and therefore in a deformation of the web, as in the three-dimensional structuring, the mesh-like volume is easily changed. The known methods for bulge-structured and vault-structured and three-dimensional wave-shaped structuring, which are briefly described in the following section, do not yet give any concrete indications for the three-dimensional structuring of meshed material webs virtually without changing the specific volume. The geometrical dimensions of the net or mesh structure on the one hand and the stiffening three-dimensional macro-structure of the bulge-shaped or vault-shaped and three-dimensionally wavy structuring on the other hand are very different. The size of the stiffening, three-dimensional macro-structure is in the cm range, while the size of the mesh or mesh structure is in the mm range.

The well-known three-dimensional arch structures of thin-walled materials are particularly gentle material with the help of an orderly bulge, wherein a thin-walled material web is supported in a curved shape on its inside by linear elements and pressurized from the outside with pressure. On the basis of a controlled self-organization with a low expenditure of energy regularly arranged, square or hexagonal bulge or vault structures ( EP 0693 008 . EP 0900 131 ) or crest-shaped bulge or vault structures ( EP 0888 208 ) or three-dimensional wave-shaped structures ( DE 10 2005 041 516 B4 ) one. The material webs structured in this way can then be converted from their curved shape into the planar shape ( DE 19856236 A1 ). While the folds in the bulge or vault structure have narrow radii, the folds of the three-dimensional wavy structures are provided with significantly larger radii, therefore called beads. This can be explained as follows: The bulge or vault structures arise in overcoming an instability point of the curved material web by a strike-through effect, whereby narrow folds, similar to the spontaneous buckling of thin walls, set by the kinetic breakdown energy. In the case of three-dimensional wave-shaped structuring, the overcoming of an instability point and a breakdown effect likewise occur, but in a modified and attenuated manner. With the help of an additional elastic material layer, which is guided between the material web to be structured and the support elements, gently rounded folds, called beads, are formed. The enclosed by these beads surface portions of the material web form calottes, which represent at least approximately the portion of a spherical surface. In contrast, in the buckling or arching of wrinkles, trapped hollows are formed, which generally do not have a spherical shape. Because of the gentle curves of the beads, the material of the material web is stressed only very little during structuring ( DE 10 2005 041 516 B4 ).

Theoretical and comparative investigations have shown that the three-dimensional structuring processes of bulge structuring and three-dimensional wavy structuring take place in a modified manner according to the Invention also for materials with small cavities, such as knitted, knitted or woven webs, even from fine threads, apply. This was not to be expected since, in particular, the mesh-shaped material webs represent spatial thread formations which can easily contract in conventional three-dimensional forming. The development according to the invention has to do with the fact that in the buckling or vault structuring process in the region of the folds or beads substantially membrane pressure forces and bending forces and not membrane tensile forces and bending forces (as in conventional embossing) are effective. In mesh and net-shaped material webs, especially in fine threads, such as wires and fibers, according to the method according to the invention in Völbstrukturieren or three-dimensional wavy structuring the active medium, such as the elastic pressure roller, with a Shore hardness of 10 to 50, preferably 25 to 35 be equipped. This particularly material-saving, three-dimensional structuring ensures that the approximately parallelogram-shaped thread arrangements of the knitted or knitted material web formed in the primary production step are stabilized and can thus substantially retain their stiffening macrostructure and their microstructure (mesh arrangement) , This also applies to the above-mentioned woven webs of fine threads. In this case, the three-dimensional structuring ensures that the approximately parallelogram-shaped mesh or stitch arrangement of the threads is retained and does not or only insignificantly spring back into the original rectangular mesh or stitch arrangement.

According to one aspect of the method according to the invention, in the case of a pronounced elastic material behavior of a woven material web (linear portion of the stress-strain diagram), an integrated manufacturing process may consist of the process of reducing the net-shaped cross section (primary manufacturing step) and the secondary three-dimensional structuring, such as vaulting and the three-dimensional wave-shaped structuring, are used. This will be exemplified later in the 1 further elaborated.

The three-dimensional structures, such as the vault-structured or three-dimensional wave-shaped structures of a knitted, knitted or woven material web can result in a larger proportion of continuously inclined projection surfaces for an oncoming fluid medium than the known two-dimensionally waved due to the dome-shaped, ie three-dimensional shape of the troughs or calottes Material web ( Prospectus of Heraeus, "Ammonia Oxidation Catalysts from Heraeus", DF Lupton et. al. ). Because in the direction of the wave crest and wave trough there is no inclined projection surface for an oncoming fluid medium.

In a further development of the method according to the invention, it is provided that the folds or beads are formed in accordance with a basic shape or the combination of a plurality of geometric basic shapes from the following group of geometric basic shapes: triangle, quadrangle, in particular square, rectangle, rhombus or parallelogram, pentagon, Hexagon (hexagon) and octagon.

A preferred embodiment of the invention provides that the structuring is a self-organizing structuring. The troughs or calottes and the folds or beads are particularly gentle on the material.

The configuration of the multidimensional structures can also be carried out according to the method according to the invention preferably with the aid of geometrically adapted support elements, for example on a roller or roller in continuous operation with the aid of geometrically adapted molds such as punch and die or die and active medium, in particular elastomer or fluidic Medium, done.

Description of preferred embodiments:

The invention will be explained in more detail below by means of embodiments with reference to figures of a drawing. First, embodiments for woven material webs and then embodiments for knitted material webs will be described. Hereby show:

1 3 is a schematic perspective view of an integrated device for producing a three-dimensionally structured, woven material web with a reduced, parallelogram-shaped net cross section by means of tensile forces acting diagonally to the material web and by means of hexagonal vault structuring;

2 schematically, analogous to 1 , in a perspective plan view, the shape development of a cylindrically curved, woven material web from its original rectangular network arrangement, image left, in a parallelogram network arrangement, image right,

3 schematically in plan view a device for reducing the network cross section of a flat, woven material web with its original rectangular network arrangement, image left, and their parallelogram network arrangements, image center and image right, by means of laterally acting shear forces,

4 1 schematically shows a device for reducing the net cross section of a knitted material web in its original net arrangement, which is fixed in the region of its at least 3-ply courses by strips with regularly attached pins and wherein the strips are held parallel by two rotatable rails,

5 schematically a device analogous to 4 , with two cross rails to stabilize the strips,

6 schematically a device according to 4 and 5 after a simultaneous rotation of the two rotatable rails,

7 schematically the device, analogous to 6 after another simultaneous rotation of the two rotatable rails,

8th 2 shows schematically the section of a device for reducing the net cross section of a knitted material web by its compression with the aid of soft pressure elements,

9 schematically, analogous to 8th , A plan view of a knitted web in its original network arrangement, image on the left, in a compressed network arrangement of its edge region, image center, and then in the subsequent compressed network arrangement of its central region, image on the right.

In the 1 is schematically an integrated device for producing a woven, hexagonal vault structured material web 1 shown with reduced formed net cross section. Here, first, a material web 1 with the output length L ₀ and the output width B ₀ at its corner 4 between the support roller 5 and the pressure roller 3 trapped and by a at the diagonal corner 6 engaging tensile force F brought into a parallelogram shape. As a result of the corner 6 attacking traction F becomes at the corner 4 the reaction force F is effective, and so from the original rectangular mesh grid is a parallelogram-shaped mesh grid (primary manufacturing step). Since the threads, such as wires, are not or only slightly stretched in a woven net grid, remains in the running direction of the material web 1 the length Lo is equal, but the width B _{1 of} the material web is formed smaller due to the inclination of the crossed threads. To prevent that in the case of a flat web of material 1 unwanted waves or wrinkles are caused, the material web 1 not deformed in a plane but in a curved shape parallelogram. This is achieved by the fact that by the tensile force F at the same time the material web 1 partly around the elastic pressure roller 3 and supporting roles 2 is bent. Then the material web 1 by pressing the pressure roller 3 which is provided with a comparatively soft elastomeric layer of Shore hardness 10 to 50, preferably 25 to 35, against the support element roller 5 pressed. Due to the comparatively soft elastomer layer of the pressure roller 3 There are the following advantages: First, there is only a comparatively small force for pressing the pressure roller 3 against the material web 1 required to achieve a highly stiffening structure depth without undesirably strongly compressing the net-like material web. Second, the soft elastomeric pressure roller 3 when pressed against the web 1 , the latter being around the support element roller 5 applies, pressed comparatively far, resulting in a large degree of overlap of the soft elastomer and in the running direction of the web 1 camber structure formed. As a result, the membrane pressure forces during the vault structuring process (in contrast to the dominant tensile forces in classical three-dimensional structuring by embossing) are advantageously enhanced. Note: This effect wins later on a knitted or knitted web 1 even more important, since threads, such as fine wires, not only tear easily under tensile load, but in the case of a knitted or knitted web, the threads, due to their spatial loops, would undesirably contract and so the initially described and desired, improved flow could be affected with a larger specific surface area. This advantageous effect of the dominant membrane compressive forces is further enhanced in three-dimensional wave-shaped structuring when a soft elastomeric intermediate layer additionally exists between the material web 1 and the support roller 5 is led (in 1 not explicitly shown). Analytical calculations of the mechanics of Prof. Böhm, TU Berlin, coincide with experimental investigations of Dr. Ing. Mirtsch GmbH the special importance of the increased membrane pressure forces (meaning the longitudinal forces along the membrane of the material web 1 ). The same applies to the vault structuring and three-dimensional wave-like structuring of mesh-like, knitted or knitted, webs of material, which is an analogous device as in 1 for the three-dimensional patterning (secondary production step). However, the primary manufacturing step (reduced net cross-section) is for a knitted or knitted web 1 because of their mesh much more sophisticated and complicated and will later in the 4 . 5 . 6 . 7 . 8th and 9 described in detail.

2 shows, in addition to the primary manufacturing step in 1 schematically a perspective view of a cylindrically curved, woven material web in their geometric Conversion from the original rectangular into a parallelogram network arrangement by the diagonal tensile load F. The cylindrical curvature of the material web 1 arises, for example, automatically by bending the web 1 around the elastic pressure roller 3 in 1 , The picture left in 2 shows a woven material web 1 with rectangular net cross-section, wherein the developed length L ₀ and the width B ₀ and the corner angle 90 ° due to the cylindrical bending of the web 1 not be changed. In the image on the right, the two diagonal forces F> 0 create a distortion of the material web 1 in a parallell-shaped mesh grid, wherein the unwound length L ₀ remains the same, but the width B ₁ <B _{0 is} formed reduced. The cat lengths of the threads of a single net grid remain the same. The vertical distance of the threads to each other is reduced in a parallelogram, and thus the area of the parallelogram mesh grid is formed reduced.

3 shows, alternatively to 2 , schematically the plan view of a flat, woven material web 1 in the transformation from the rectangular into a parallelogram network arrangement of the threads. For a woven material web 1 This transformation can be done by using rails 7 at the lateral edges of the web 1 attack and shear forces F on the web 1 transferred, the shear forces F not only at the edges but up to the middle of the web 1 are effective. But that is only with a woven material web 1 (not with a knitted or knitted web 1 ) possible, since here in and across the direction of the web 1 separate threads are arranged crosswise and form an approximately planar network arrangement. In the shear-shaped deformation of the woven material web as a result of in 3 shown forces F occur simultaneously diagonal tensile forces and in turn transverse to diagonal compressive forces (in 3 not explicitly shown). These diagonally effective compressive forces can cause unwanted wrinkles or waves in the material web 1 cause. Therefore, the flat material web 1 held at its shear-shaped deformation by pressing an upper, flat plate and a lower, flat plate in its planar shape. In 3 For the sake of simplicity, the explicit representation of the upper flat plate and the lower, flat plate was dispensed with.

4 schematically shows a device for forming a reduced network cross-section (primary production step) of a knitted web 1 in the starting position. Care is taken to ensure that the threads are in particular in the range of at least 3-ply courses 8th not or only slightly contract. The at least 3-ply courses 8th the material web 1 be through pins 9 on moving bars 10 are attached, fixed. In the illustrated knitted web 1 By way of example, catalytic converter nets made of noble metal-containing wires (analogous to "warp knitting") with loops in the region of the at least 3-ply courses are formed by means of a warp knitting machine with open tricot binding 8th and zigzag, 2-ply mesh rows 11 of wires. Exemplary possess the strips 10 a width of 1.5 mm, corresponding to the width of a least 3-ply row of stitches 8th , By way of example, in the initial position, the clear distance between the strips 10 the value 1.5 mm, corresponding to the width of a 2-ply net rows 11 , In very fine mesh, according to the in the DE 4300791 A1 18 to 32 stitches per inch, in the initial position is the distance between the minimum 3-ply courses 8th only about 1 mm to each other. For the latter case, one can choose either the width of the strips 10 in an adapted manner narrower, for example, 0.5 mm and the clearance between the strips also 0.5 mm choose. Because the production and stability of such narrow and at the same time long strips 10 with the pins 9 are difficult to realize, for example, you can use the width of 1.5 mm of the strips 10 and the clear distance 1.5 mm between the strips 10 keep, then only every third, at least 3-layer course 8th with the help of fine pins 9 is fixed (in 4 not explicitly shown). The 2-ply net rows 11 consist of two parallelogrammfömigen network cross-sections 12 (marked in black) together, their geometric orientation being different due to the zigzag wires arranged. The strips 10 be at their ends by grooved, rotatable rails 13 guided. From above, the knitted material web 1 supported by a padded, thin plate. On the appearance of the padded, thin plate was in 4 simplified omitted.

5 shows, as an extension to 4 , Schematically a device in a plan view, right picture, and in a cross section AA, left picture, with narrow strips 10 (which could easily bend) with additional pins 14 (arranged on the bottom of the strips 10 ) stabilized and movable in two cross rails 15 be guided. The rotatable rails 13 and the crossbars 15 are on the bottom plate 16 fixed. For better clarity was on the explicit representation of the web 1 waived.

6 shows, analogous to 4 and 5 schematically the apparatus for forming a reduced network cross-section (primary production step) for a knitted web 1 in the advanced position of rotating rails 13 after about 20 ° rotation, reducing the distance between the bars 10 formed reduced to each other. As a result of about Zig-zag course of the wires in the region of the 2-ply network rows 11 form from the originally two parallelogram net lattices (marked in black in 4 with different orientations of the parallelogram) a geometrically extended and thus narrower, parallelogram-shaped mesh grid 17 and an approximately rectangular mesh grid 18 , which already have a reduced network cross-section compared to the starting position in 4 exhibit.

7 shows, analogous to 4 ., 5 and 6 schematically the device in its final position after the rotatable rails 13 rotated by an angle of about 40 ° and thus the distance of the strips 10 each other was formed significantly closer to each other. As a result, the widths of the 2-ply network rows 11 (between the minimum 3-ply courses 8th ), due to both in the same direction aligned and narrower, parallelogram-shaped network cross-sections 19 and 20 (marked black) formed small. After removing an upper padded, thin plate (in 7 not explicitly shown) and after gently removing the deformed material web 1 from the pins 9 you get the flat web 1 with significantly reduced network cross-section. The vaulting or three-dimensional wavy structuring of a knitted or knitted web 1 with a reduced network cross-section then takes place in the secondary manufacturing step, analogous to that in the 1 described. Therefore, the presentation of the secondary manufacturing step in 7 simplified omitted.

8th schematically shows a plan view and in cross section of the section of an alternative device for the reduction of the network cross-section (primary production step) of a knitted material web 1 , where soft printing elements 21 . 22 partially against the web 1 press, then gradually parallel to the material web 1 be moved against each other and thereby by adhesion a compression in the web 1 cause. In 8th The explicit representation of a single thread, such as wire, of the material web is sufficient 1 , according to the in the 4 Bold wire shown in black as the other wires of the knitted web 1 behave analogously. In contrast to the 4 to 7 the reduced network cross-section is not by means of parallel-shaped reshaping of the net grid but by a stepwise upsetting of the web 1 reached. First press the offset opposite pressure elements 21 . 22 , For example, in the shape of fingertips, with the surface force F _D against the material web, wherein they are against the at least 3-ply courses 8th Press, as the 2-ply net rows 11 lie lower. The soft pressure elements 21 . 22 At the same time, several of the at least 3-ply courses can be used 8th overlap. In 8th are simplistic only two printing elements 21 . 22 , each only a single at least 3-layer course 8th touching, shown (section AA, picture left, in the starting position, section BB, picture right, in the compressed position). The lower picture on the left shows the zigzag arrangement of the wire in the area of the 2-ply net rows 11 (between the minimum 3-ply courses 8th ). The result of the soft pressure elements 21 . 22 on the material web 1 transmitted forces F _D generate in the web 1 Pressure membrane forces F _N (marked as arrows in the picture below). As a result, the material web 1 compressed. Because of the spatial loops of the wires in the range of at least 3-ply courses 8th The mesh loops can be made slightly larger in cross-section, and the wires in the area of the 2-ply mesh rows 11 are formed curved. In this way, the spacing of the courses becomes 8th formed smaller to each other and thus the network cross-section in the range of 2-ply network rows 11 made smaller. A zigzag arrangement of soft printing elements 21 . 22 is advantageous, since thereby when upsetting the material web 1 disturbing instabilities with the risk of buckling of the material web 1 can be avoided. This can be explained approximately as an incremental reshaping, with stepwise small forming paths with superimposed membrane compressive forces and shear forces. That will be in the following 9 described in more detail.

9 schematically shows a plan view of a device for a stepwise sequence in reducing the network cross-section of a knitted web 1 from the edge towards the center. The picture on the left shows the mesh grid of the original material web 1 , The circles with the arrows 23 . 24 (Center image) identify the areas where individual soft print elements 21 . 22 offset against the material web 1 Press, thereby causing membrane pressure and shear forces and gradually the web 1 compress. Exemplary are the areas 23 . 24 chosen so that in their circles two rows of stitches 8th through the soft pressure elements 21 . 22 (please refer 8th ). But it can also be several courses 8th be detected (in 9 not explicitly shown). By the compression of the areas 23 and 24 at the edge of the material web 1 its original width B _{0 is} reduced to the width B ₁ (center picture). Alternatively, a device, wherein a fixed series of zigzag arranged soft printing elements 21 against an oppositely arranged fixed series of zigzag-shaped soft printing elements 22 presses, apply. Although this device is more complex than the fingertips of two hands, but allows a simultaneous compression of the web 1 the courses 8th (in 8th and 9 not explicitly shown). The picture on the right in 9 shows one then advanced, upsetting forming of the courses 8th in the middle region of the material web 1 , whereby the width B _{1 of} the material web 1 is further reduced to the width B ₂ . This is then continued until the opposite edge of the web 1 (in 9 not explicitly shown).

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 92102301 [0003]
• DE 4300791 A1 [0003, 0003, 0045]
• WO 98/40910 [0007]
• US 2005/0252182 A1 [0007]
• DE 102006062189 B4 [0008, 0008, 0008, 0008, 0008, 0008, 0008]
• DE 1020041555 B4 [0008]
• EP 0693008 [0025]
• EP 0900131 [0025]
• EP 0888208 [0025]
• DE 102005041516 B4 [0025, 0025]
• DE 19856236 A1 [0025]

Cited non-patent literature

• Prospect of Heraeus, "Ammonia Oxidation Catalysts from Heraeus", DF Lupton et al., Page 09 [0003]
• Prospectus of Heraeus, "Ammonia Oxidation Catalysts from Heraeus", DF Lupton et. al. [0028]

Claims (11)

Method for producing a multi-dimensionally structured, knitted or knitted material web with the steps: In a primary manufacturing step, juxtaposed brush-like elements or soft printing elements press against a knitted or knitted web of material consisting of at least 3-ply courses and 2-ply thread arrangements therebetween, the latter having a lower height than the at least 3-ply courses whereby the web is fixed while substantially maintaining the thickness of the at least 3-ply courses, and then the brush-like elements or the soft printing elements are moved towards each other, thereby reducing the distance between the at least 3-ply courses of the web and so on Distance of the threads is formed smaller to each other. - The web is on one side partially supported by line-shaped support elements, which are preferably arranged on a roller, and on its opposite side presses a knitting medium, such as a resilient pressure roller, against the web, whereby a multi-dimensional structuring is formed with juxtaposed structures , as bulge-shaped or vault-shaped structures, provided with depressions and folds, or three-dimensional wave-shaped structures by means of additional elastic layer, which is guided between the support elements and the material web, provided with calottes and beads, whereby the material web is multi-dimensionally stiffened and the material of the material web especially spared. - At all locations of the material web, a small and substantially uniform free mesh cross-section is formed for a fluid medium flowing through the material web. A method according to claim 1, characterized in that the brush-like elements are formed as pins, which are arranged in rows on narrow strips, lined up. A method according to claim 2, characterized in that the ends of the strips are performed grooved and the strips are guided by engaging, fluted rotatable rails adapted. A method according to claim 1, characterized in that the soft pressure elements are formed as juxtaposed, elastic knob elements, such as manually moving fingertips or mechanical knobs. Method for producing a multidimensionally structured, woven material web with the steps: - In a primary manufacturing step, a woven material web, as with rectangularly arranged threads, deformed by acting on the edges of the material web mechanical elements in a parallelogram arrangement of the threads, whereby the distance of the threads to each other and the net free cross section is formed reduced. - The web is then partially supported on one side by linear elements, which are preferably arranged on a roller, and on its opposite side pushes a knitting medium, such as a resilient pressure roller, against the web, whereby a multi-dimensional structuring formed with juxtaposed structures is provided as bulge-shaped or vault-shaped structures, with troughs and folds, or three-dimensional wave-shaped structures by means of additional elastic layer, which is guided between the support elements and the material web, provided with domes and beads, wherein the material web is stiffened multi-dimensionally and the material of Material web is particularly spared. - At all locations of the material web a small and substantially uniform free network cross-section for a material flowing through the material is formed. A method according to claim 5, characterized in that the mechanical elements are formed in the shape of laterally engaging on a flat material web pushers or in the form of diagonally engaging on a curved material web tension members. A method according to claim 1 and claim 5, characterized in that the active medium, such as the elastic pressure roller, with a Shore hardness of 10 to 50, preferably a Shore hardness 25 to 35, is equipped. Method according to at least one of claims 1 to 7, characterized in that the multi-dimensional structures are formed by utilizing a controlled self-organization. Method according to at least one of claims 1 to 7, characterized in that the support elements are arranged on a core or in a tool which / which has a contour of a desired structure of the folds or bulges and troughs or calotte adapted contour or by geometrically adapted Forming tools or an active medium is adjusted. Method according to at least one of claims 1 to 9, characterized in that the thread arrangements of the material web of metal, precious metal, plastic or textile fibers are formed. Use of the material web prepared by the process according to claims 1 to 10 for catalyst networks, in particular of noble metal, such as platinum-rhodium or platinum-rhodium-palladium, for chemical reaction engineering apparatus or for filter media.

Images