EP1554208A1

EP1554208A1 - Former for a strip-producing or strip-processing machine

Info

Publication number: EP1554208A1
Application number: EP03776804A
Authority: EP
Inventors: Johannes Boppel; Peter Wilhelm Kurt Leidig
Original assignee: Koenig and Bauer AG
Current assignee: Koenig and Bauer AG
Priority date: 2002-10-19
Filing date: 2003-10-20
Publication date: 2005-07-20
Anticipated expiration: 2023-10-20
Also published as: EP1554122A1; US20060096476A1; EP1554208B1; WO2004037538B1; EP1997759B1; ATE435180T1; EP1655257B1; WO2004037698B1; ATE337255T1; JP2006502937A; AU2003286098A1; WO2004037539A2; EP1655257A1; ES2306904T3; DE50309490D1; EP1556218B1; CN1705608A; WO2004037539B1; WO2004037696A3; WO2004037538A1

Abstract

A folding element for a printing press, or sheet handler, has the folding guide (03) with a microporous surface to generate an air cushion and thereby prevent mechanical contact between the guide and the sheets. The pore size is less than 500 microns and the pores are evenly distributed over the surface of the guide. Air is blown through the porous surface from inside the hollow guide.

Description

description

Folding former of a web-producing or processing machine

The invention relates to folding former of a web-producing or processing machine according to the preamble of claim 1 or 2.

A folding former is known from DE 4435 528 A1, which has air outlet openings on its side cooperating with the web. By arranging openings in a base plate and in a cover plate that can be moved against the base plate, the effective air outlet openings can be varied from a maximum size (full coverage) to zero (no coverage).

US 5423468 A shows a lead element which has an inner body with bores and an outer body made of porous, air-permeable material. The holes in the inner body are only provided in the expected wrapping area.

From DE 198 54 053 A1, a sheet-guiding device is known, blown air flowing through bores, slots, porous material or nozzles in a guide surface of a guide element and thus guiding the sheet without contact.

The invention has for its object to provide formers of a web-producing or processing machine.

The object is achieved by the features of claim 1 or 2.

The advantages that can be achieved with the invention are, in particular, that a very low-friction folding former is created. By means of a micro opening Air cushion created creates a high degree of homogeneity over the expansion of the air cushion with low losses at the same time.

By means of air outlet openings with diameters in the millimeter range, forces (impulse of the beam) can be applied selectively to the material, by means of which these are kept away from the component in question, while a wide support and primarily the effect of a trained air cushion are borne by the distribution of micro-openings with a high hole density comes. The cross-section of holes previously used was, for example, 1 to 3 mm, whereas for the micro-openings the cross-section was at least a power of ten smaller. This creates significantly different effects. For example, the distance between the surface supporting the openings and the material web, e.g. B. reduce web or a strand, significantly reduce the volume flow of fluid, and thereby possibly significantly reduce leakage currents escaping outside the effective range with the web.

In contrast to components with openings or bores of opening cross sections in the range of millimeters and a hole spacing of several millimeters, a much more homogeneous surface structure is advantageously created when micro-openings are formed on the surface. Micro-openings are understood here to mean openings on the surface of the component which have a diameter of less than or equal to 500 μm, advantageously less than or equal to 300 μm, in particular less than or equal to 150 μm. A “hole density” for the area provided with the micro-openings is at least one micro-opening per 5 mm ² (= 0.20 / mm ² ), advantageously at least one micro-opening per 3.6 mm ² (= 0.28 / mm ² ).

The micro-openings can advantageously be designed as open pores on the surface of a porous, in particular micro-porous, air-permeable material or as openings of continuous micro-bores of small cross-section, which extend through the wall of a supply chamber to the outside. In order to achieve a uniform distribution of air escaping on the surface of the material in the case of the use of microporous material, without at the same time requiring high layer thicknesses of the material with high flow resistance, it is expedient for the folding former to have a firm, air-permeable support in the area in question , on which the microporous material is applied as a layer. Such a carrier can be pressurized with compressed air, which flows out of the carrier through the microporous layer and thus forms an air cushion on the surface of the component.

This carrier can in turn be porous with a better air permeability than that of the microporous material; however, it can also be formed from a flat material or molded material which encloses a cavity and is provided with air passage openings. Combinations of these alternatives are also possible.

In order to achieve a uniform air distribution, it is also desirable that the thickness of the layer corresponds at least to the distance between adjacent openings of the carrier.

If micro-bores are used, an embodiment is advantageous in which the region of the former that faces the web and has the micro-openings is designed as one or more inserts in a carrier. In further training, the insert can be detachably and, if necessary, exchangeably connected to the carrier. This makes it possible to clean and / or replace inserts of different types of microperforations to adapt to different materials, web tensions, number of layers of the strand and / or partial web widths.

Exemplary embodiments of the invention are shown in the drawings and are described in more detail below. Show it:

Figure 1 is a schematic section through a first embodiment of the former with porous material.

FIG. 2 shows a section perpendicular to FIG. 1 through a leg area of the former;

3 shows a schematic section through a second embodiment with porous material;

4 shows a schematic section through a third embodiment with porous material;

FIG. 5 shows a schematic plan view of a carrier body of a folding former according to FIG. 3 or 4;

6 shows a schematic section through a first embodiment of the former with micro-bores;

7 shows a section perpendicular to FIG. 6 through a leg region of the former;

8 shows a schematic section through a second embodiment with microbores;

9 shows a schematic section through a third embodiment with microbores;

10 shows a schematic plan view of a former with a separated nose. 11 shows a schematic front view of a folding device having micro-openings.

Fig. 1 shows a schematic section through one of a web 06, z. B. material web 06 or printing material web 06, in particular paper web 06, folded former 01. The former 01 has two leg regions 03 running at an acute angle to one another and a nose region 04, and a pair of pull rollers 02 at the apex of the angle spanned by the outer sides of the leg regions 03. The web 06 is fed to the former 01 from above parallel to the plane of the drawing, and during the passage through the former 01 the side edges of the material web 06 are folded out of the plane of the drawing, so that a simply longitudinally folded web 06 results, which in orientation across the plane of the drawing roller pair 02 happens. The same applies equally if, instead of a web 06, a partial web or a strand of superimposed webs or partial webs are guided over the former 01.

The folding former 01 has, at least in a region of its leg region 03 or its leg regions 03, openings 10 designed as micro-openings 10 on an outer side which cooperates with the web 06. At least in this area, it has a hollow interior 07 or cavity 07 which can be acted upon with compressed air by a feed, not shown.

Through the micro-openings 10 flows in operation from the cavity 07, for. B. the chamber 07, in particular pressure chamber 07, fluid under excess pressure against the environment, for. B. a liquid, a gas or a mixture, especially air. A corresponding supply of compressed air into the cavity 07 is not shown in the figures.

In a first embodiment, the micro-openings 10 are open pores on the surface of a porous, in particular microporous, air-permeable material 09, for. B. from an open-pore sintered material 09, in particular made of sintered metal. The pores of the air-permeable porous material 09 have an average diameter (average size) of less than 150 μm, for. B. 5 to 60 microns, in particular 10 to 30 microns. The material 09 is formed with an irregular, amorphous structure.

The cavity 07 can, at least on the area interacting with the web 06, be formed essentially solely from a body which closes off the cavity 07 on this side from a porous solid material (i.e. without further load-bearing layers of appropriate thickness). This essentially self-supporting body is then designed with a wall thickness of greater than or equal to 2 mm, in particular greater than or equal to 3 mm. For example, two tubular bodies made of the porous material 09 can form the leg regions 03 of the former 01, and possibly a suitably shaped hollow body made of the material 09, which form the nose region 04, or nose 04 for short. The complete folding former 01, including a former plate with a microporous layer 09, can also be designed.

In order to achieve a uniform distribution of air emerging on the surface of the microporous material 09, without simultaneously requiring high layer thicknesses of the material 09 with a correspondingly increased flow resistance, it is provided in a first embodiment (FIG. 1) that the former 01 in Leg region 03 has a solid, at least regionally air-permeable carrier 08, in particular carrier body 08, on which microporous material 09 is applied as layer 09. Such a carrier body 08 can be pressurized with compressed air, which flows out of the carrier body 08 through the microporous layer 09 and thus on the surface of the leg or nose area 03; 04 forms an air cushion. In a preferred embodiment, the porous material 09 is thus not designed as a load-bearing solid body (with or without a frame construction), but rather as a coating 09 on a carrier body 08, in particular made of metallic carrier material, which has passages 15 or through openings. Under "non-load-bearing" Layer 09 iN.m. In contrast to, for example, "load-bearing" layers known from the prior art, the support body 08 is understood to be a structure, the layer 09 being supported over its entire layer length and entire layer width in each case on a multiplicity of support points of the support body 08. The support body 08 has, for example, on its width and length interacting with the layer 09, a plurality of non-contiguous passages 15, for example bores 15. This embodiment is clearly different from an embodiment in which there is an over the entire effective area extending porous material is designed to be self-supporting over this distance, is supported only in one end region on a frame or support, and must therefore have a corresponding thickness.

The leg regions 03 of the former 01 designed as web guide plates 03 in FIG. 1 are each supported by a carrier 08, e.g. B. a housing made of sheet metal, the side facing the material web 06 is broken many times and carries the microporous layer 09. An air flow that flows through the microporous layer 09 from the interior 07 forms an air cushion on its surface, which prevents direct contact between the web guide plates 03 and the web 06 to be guided by them. The web 06 therefore passes the former 01 smoothly and evenly without the risk of getting stuck or being damaged.

In particular, an embodiment is advantageous in which the folding former 01 is designed with the feedthroughs 15 and the layer 09 in the region of its converging cheeks, at least in the kink region, ie in the region of the “edge” deflecting the web 06. These feedthroughs 15 and the layer 09 can also be arranged in the area of the cheeks as well as in the edge area of the surface, ie, encompass the fold edge. Advantageously, this fold edge is not sharp-edged, but has a curve with a radius R. In FIG. 2, a section of an advantageous one Execution represented by one side of the former 01 in the leg area 03. The "edge" which is effective for the folding is represented by a tube 08 (or spar 08) formed carrier 08 is formed, which has openings of the bores 15 at least in a wrapping or contact area of the web 06 and is coated with the microporous layer 09. In principle, two such converging pipes 08 with corresponding struts are sufficient as the former 01 to form the former 01. In the exemplary embodiment, the former 01 has a cover 11, for. B. a funnel plate 11, short plate 11, which, as shown, is flush with the effective surface of the spar 08. However, it could also be arranged to form a free space between sheet metal 11 and tensioned sheet 06 offset "downward" away from sheet 06. This sheet 06 can also be made entirely or partially with openings 10; 15 and possibly layer 09 and from Be blown with compressed air from a cavity "below" (only indicated by dashed lines).

The folding former 01 can also be made split in an embodiment not shown. That is, the two spars 08 each form a symmetrical half of the upper folding former area with a “half” funnel plate 11. A common nose region 04 is assigned to the two former halves. The same applies to the other configurations for the spars 08 and the nose region 04 said.

3 shows an embodiment in which the areas blown with compressed air and provided with the layer 09 and bores 15 unite in the nose area 04 to form a common cavity 07. Bores 15 and the layer 09 are also arranged there at least in the area of the surfaces interacting with the web 06.

In a further development for the representation in FIG. B. with a uniform coating - the cavity 07 'in the nose area 04 from the cavity 07 of the leg areas 03 to be executed separately and have their own supply of compressed air. The nose area 04 and the leg area 03 can then, for example, be subjected to different pressures (for example higher in the nose area 04). The choice of material, dimensioning and pressurization are selected such that 1 to 20 standard cubic meters per m ² , in particular 2 to 15 standard cubic meters per m ² , emerge from the air outlet surface of the sintered material 09 per hour. The air outlet of 3 to 7 standard cubic meters per m ² is particularly advantageous.

The sintered surface from the cavity 07 is advantageously subjected to an excess pressure of at least 1 bar, in particular more than 4 bar. It is particularly advantageous to apply an overpressure of 5 to 7 bar to the sintered surface.

4 shows an embodiment of the former 01, with microporous materials 09; for the layer 09 in different areas of the former 01; 09 'different property and / or layer thickness is used. The layer 09 'in the nose area 04 is formed such that, for. B. the emerging air flow per unit area is greater than in the cheek or leg area 03 of the former 01. Thus, the nose area 04 has, for example, a layer 09 'of a material whose average pore size is larger, the proportion of open outer area per unit area is larger and / or the layer thickness is smaller than in the material of the layer 09 in the leg region 03. The air-permeable material 09 of the leg regions 03 has, for example, pores with an average size of 10-30 μm and the nose region 04, for example, 25 to 60 μm. As shown, the areas of the different layers 09; 09 'must be supplied with compressed air via a common chamber 07 (cavity 07). However, separate chambers 07 can also be provided for this purpose, which can then optionally be pressurized with compressed air of different pressure. As a result (variation of pore size and / or pressure), the air outlet in the leg area 03 is, for example, 2 to 15 standard cubic meters per m ² and that in the nose area is 7 to 20 standard cubic meters per m ² , with the condition that the latter is larger than the former.

Fig. 5 shows schematically a plan view of the former 01 with converging Spars 08 and that in the nose area 04. However, the illustration shows the former 01 without the layer 09 (or the layers 09; 09 'of different material) so that the indicated openings of the passages 15 are visible.

In the exemplary embodiments shown, the carrier material 08 essentially absorbs the weight, shear, torsion, bending and / or shear forces of the component, which is why a corresponding wall thickness (for example greater than 3 mm, in particular greater than 5 mm) of the Carrier body 08 and / or a correspondingly stiffened construction is selected. The porous material 09 outside the bushing 15 has z. B. a layer thickness that is less than 1 mm. A layer thickness between 0.05 mm and 0.3 mm is particularly advantageous.

A proportion of the open area in the area of the effective outer surface of the porous material 09, here denoted by degree of opening, is between 3% and 30%, preferably between 10% and 25%. In order to achieve a uniform air distribution, it is also desirable that the thickness of the layer corresponds at least to the distance between adjacent openings in the bores 15 of the carrier body 08.

The wall thickness of the carrier body 08 at least in the layer 09; 09 'supporting area is z. B. greater than 3 mm, in particular greater than 5 mm.

The carrier body 08, however, can also be made of porous material 09, but with better air permeability - e.g. B. a larger pore size - than that of the microporous material of the layer 09. In this case, the openings of the carrier 08 are formed by open pores in the area of the surface, and the passages 15 are formed by the channels which are randomly formed on the inside due to the porosity. The carrier body 08 can, however, also be formed from any flat material or shaped material which surrounds the cavity 07 and is provided with passages 15. Combinations of these alternatives also come into play Consideration.

The inside cross section of a feed line, not shown, for supplying the compressed air to the former 01 is less than 100 mm ² , preferably it is between 10 and 60 mm ² .

In a second embodiment (Fig. 6 to 9), the micro-openings 03 are designed as openings through holes 12, in particular micro-holes 12, which are characterized by a z. B. formed as a pressure chamber 07 cavity 07 delimiting wall 13, z. B. chamber wall 13, extend outwards. The chamber wall 13 can advantageously be formed in the leg area 03 as a tube 13 or spar 13. The holes 12 have z. B. a diameter (at least in the region of the openings 10) of less than or equal to 500 μm, advantageously less than or equal to 300 μm, in particular between 60 and 150 μm. The degree of opening is z. B. at 3 to 25%, especially at 5 to 15%. A hole density is at least 1/5 mm ² , in particular at least 1 / mm ² up to 4 / mm ² . The wall 13 thus has a microperforation, at least in one leg area 03. The microperforation advantageously extends, as in the first exemplary embodiment, the feedthroughs 15 and layer 09, at least in the leg region 03 and a nose region 04.

A u.a. the wall resistance influencing the flow resistance of the chamber wall 13 containing the bores 12 is, for. B. at 0.2 to 3.0 mm, advantageously at 0.2 to 1.5 mm, in particular from 0.3 to 0.8 mm. A reinforcing structure (not shown), for example a support, in particular a metal support, extending in the longitudinal direction of the bars 13, on which the chamber wall 13 is supported at least in sections or at points, can be arranged in the cavity 07.

6 to 9 show the modified versions of FIGS. 1 to 4, in which instead of the carrier 08 and the layer 09; 09 'the wall 13 with the micro-openings 12 occurs. 6, the leg regions 03 have the microbores 12 in the chamber wall 13 facing the web 06 in at least their fold edge regions.

7 shows the design of the chamber wall 13 as a tube 13 which has microperforation (microbores 12) at least in the fold edge region.

In FIG. 8, corresponding to FIG. 3, the formation of the cavity 07 and the arrangement of micro-openings 10 into the nose area 04 are shown.

For the execution of the micro-openings 03 as openings of holes 12 is such. B. an overpressure in the chamber 04 of a maximum of 2 bar, in particular from 0.1 to 1 bar is advantageous.

FIG. 9 shows, corresponding to FIG. 5, the formation of zones of different types of microperforation. For example, the diameter of the microbores 12 'in the nose area 04 (e.g. 90 to 150 μm) may be larger than that in the leg area 03 (e.g. 60 to 110 μm) and / or the hole density in the nose area 04 (greater than 0. 3 / mm ² ) larger than that in the leg area 03 (e.g. larger than 0.2 / mm ² ). Instead of or in addition, it is also possible to use different cavities 07; 07 'for the nose and thigh area 03; 04, the cavity 07 'assigned to the nose area 04 then being subjected to a higher overpressure (e.g. less than 3 bar but greater than the overpressure in the leg area 03) than that in the leg area 03 (e.g. less than 2 bar) , in particular less than 1 bar).

The bores 12 can be cylindrical, funnel-shaped or with another special shape (for example in the form of a Laval nozzle).

The microperforation, ie the production of the bores 12, is preferably carried out by Drilling using accelerated particles (e.g. liquid such as water jets, ions or elementary particles) or using electromagnetic radiation with a high energy density (e.g. light using a laser beam). Production using an electron beam is particularly advantageous.

The side of the web 06 facing the wall 12 having the holes 12, for. B. a wall made of stainless steel, has in an advantageous embodiment a dirt and / or paint-repellent finish. It has a coating, not shown, which does not cover the openings 10 or bores 12 - for. B. nickel or advantageously chromium - which z. B. is additionally processed - e.g. B. structured with micro ribs or a lotus flower effect or preferably mirror polished).

The wall 13 having the bores 12 is designed in one variant as one insert or several inserts in a carrier. The insert can be fixed or changeable to the carrier. The latter is advantageous with regard to cleaning or exchanging inserts of different types of microperforations to adapt to different colors, printing forms etc.

10 shows a schematic diagram of a further embodiment of the folding former 01, the leg regions 03 being formed by the bars 08 and the nose region 04 by a separate carrier 08 'or carrier body 08' forming a cavity 07 '. In FIG. 10, the layer 09 is in the leg and nose area 03; 04 not shown. Since this embodiment can be applied in the same way to the exemplary embodiment with the microbores 12, the components have been designated twice accordingly. The leg regions 03 then have the walls 13 and the nose region 04 the chamber wall 13 '.

In an embodiment that is not shown, the upper part, which carries the leg regions 03, can also be designed as a double-walled hollow body, which bores 15 and Layer 09, or the micro-holes 12 - in the leg area 03 and possibly in the triangular area in between - has.

In a further development (Fig. ^* 11) 02 is not formed, the pair of drawing rollers the fold-forming as rotatable rollers, but as folding device 02 having two opposing surfaces, which on its side facing the web 06 (or strand) sides having micro-openings 10. These surfaces having the micro-openings 10 can be arranged on a common carrier body 16 including a common cavity 07, on a common carrier body 16 having two separate cavities 07, or on two separate carrier bodies 16 each having a cavity 07. The micro-openings 10 are designed in one of the two above-mentioned designs - as open pores of a porous material 09 or as openings in micro-bores 12 - and can be acted upon with fluid from the cavity 07. In one case, a layer 09 in connection with bores 15 is then applied to the inside of the carrier body 16, in the other case this side has microbores 12. The web 06 or the strand is passed through the mutually facing surfaces and receives its longitudinal or back fold. For this purpose, for example, the distance between the surfaces tapers in the direction of the running web 02.

The folding device 02 can advantageously be carried out in addition to one of the aforementioned folding former 01 having micro-openings 10, or else independently of the execution of the folding former 01 in the embodiment described.

LIST OF REFERENCE NUMBERS

01 former

02 pair of pull rollers, folding device

03 leg area, web guide plate

04 nose area, nose

05 -

06 Web, material web, printing material web, paper web

07 interior, cavity, chamber, pressure chamber

08 carrier, carrier material, carrier body, tube, spar

09 microporous material, sintered material, layer, microporous, coating

10 opening, micro opening

11 cover, sheet metal

12 hole, micro hole

13 wall, chamber wall, tube, spar

14 pressure gap

15 opening, passage, drilling

16 carrier body

07 'cavity

08 'carrier, carrier body

09 'microporous material

12 'bore, micro bore

13 'chamber wall

Claims

Expectations

1. Folding former (01) of a web-producing or processing machine, with two leg regions (03) which converge at an angle and which, in an area interacting with a web (06) to be folded, have a plurality of openings (03) in their surface for the exit of a pressurized fluid, characterized in that the openings (10) are designed as micro-openings (10) with an invariable diameter of less than 500 μm.

2. Folding former (01) of a web-producing or processing machine, characterized in that the folding former (01) has porous material (09) through which fluid can flow, at least in an area of its surface which interacts with a web (06) to be folded.

3. Folding former (01) according to claim 2, characterized in that the microporous material (09) has on its surface a plurality of micro-openings (10) formed by open pores for the exit of a pressurized fluid.

4. Folding former (01) according to claim 3, characterized in that at least two leg regions (03) converging at an angle have micro-openings (10) in an area of their surface which interacts with a web (06) to be folded

5. folding former (01) according to claim 1 or 4, characterized in that the folding former (01) in addition to the micro-openings (10) in the leg regions (03) in a surface of a nose region (04) has micro-openings (10).

6. folding former (01) according to claim 1 or / and 5, characterized in that the micro-openings (03) as open pores of a porous through which the fluid flows Materials (09) are executed.

7. folding former (01) according to claim 2 or 6, characterized in that the pores of the fluid-permeable porous material (09) has an average diameter of

5 to 50 μm, in particular 10 to 30 μm.

8. folding former (01) according to claim 2 or 6, characterized in that the porous material (09) is designed as an open-pore sintered material (09), in particular as a sintered metal.

9. folding former (01) according to claim 2 or 6, characterized in that the microporous material (09) as a layer (09) on a load-bearing, at least partially fluid-permeable and a cavity (07; 07 ') enclosing support body (08; 08' ) is trained.

10. The former (01) according to claim 9, characterized in that the carrier (08) on its side facing the layer (09) has at least one supporting surface connected to the layer (09) and a plurality of openings for the supply of the fluid into the Layer (09) has.

11. The former (01) according to claim 10, characterized in that the layer (09) in the area of the wing has a thickness of less than 1 mm, in particular from 0.05 mm to 0.3 mm.

12. The former (01) as claimed in claim 9, characterized in that the support body (08) has a plurality of, in particular non-contiguous, passages (15) on its width and length which cooperate with the layer (09).

13. The former (01) according to claim 9, characterized in that a wall thickness of the support body (08) or at least the wall (09) carrying the wall is greater than 3 mm, in particular greater than 5 mm.

14. The former (01) according to claim 9, characterized in that the carrier body (08) is formed at least in part from a porous material (09) with a better air permeability than the microporous material (09).

15. The former (01) according to claim 9, characterized in that the carrier body (08) is formed at least in part from a flat material which surrounds a cavity (07) and is provided with openings.

16. The former (01) according to claim 9, characterized in that the carrier body (08) in the leg region (03) is designed as a tube (08) provided with bushings (15).

17. Folding former (01) according to claim 2 or 6, characterized in that the microporous material (09) has a layer thickness which corresponds at least to the distance between adjacent passages (15) of the carrier (08).

18. Folding former (01) according to claim 1 and / or 5, characterized in that the openings (10) as outwardly directed micro-openings (10) of micro bores (12) in one of the folding former (01) to the outside (06) down wall (13; 13 ') are executed.

19. The former (01) according to claim 18, characterized in that a diameter of the openings (03) is less than or equal to 300 μm, in particular between 60 and 150 μm.

20. Folding former (01) according to claim 18, characterized in that a wall thickness of the wall (13) is 0.2 to 3.0 mm.

21. The former (01) according to claim 18, characterized in that a hole density, ie a number of openings (10) per unit area, is at least 0.2 / mm ² for the area provided with the microbores (10).

22. Folding former (01) according to claim 1 or 3, characterized in that 1 - 20 standard cubic meters of air per hour emerge on a square meter of the surface having the micro-openings (10).

23. Folding former (01) according to claim 1 or 3, characterized in that 2-15, in particular 3-7, standard cubic meters of air per hour emerge on a square meter of the surface having the micro-openings (10).

24. The former (01) according to claim 2 or 6, characterized in that the porous material (06) is acted upon from the inside with at least 1 bar overpressure.

25. The former (01) according to claim 2 or 6, characterized in that the porous material (06) is pressurized from the inside with more than 4 bar, in particular with 5 to 7 bar, of the fluid.

26. The former (01) according to claim 1 or 2, characterized in that a feed line for supplying the fluid to the former (01) has an internal cross section of less than 100 mm ² , in particular between 10 and 60 mm ² .

27. The former (01) according to claim 1 or 2, characterized in that the pressurized fluid is designed as compressed air.

28. The former (01) according to claim 1 or 3, characterized in that a part of the former (01) carrying the micro-openings (10) is designed as a releasable insert on a carrier.

29. The former (01) according to claim 5, characterized in that the fluid permeability per unit area in the nose area (04) is different from that in the leg area (03).

30. folding former (01) according to claim 5, characterized in that the fluid permeability per unit area in the nose region (04) is higher than in the leg region (03).

31. The former as claimed in claim 5, characterized in that a common cavity (07) is formed for supplying the microbores (10) in the leg region (03) and in the nose region (04) with the fluid.

32. folding former according to claim 5, characterized in that for the supply of the micro-bores (10) in the leg region (03) and in the nose region (04) fluid-separated cavities (07) are formed.

33. folding former according to claim 5 and one of claims 2 or 6, characterized in that the same microporous material (09) is provided in the leg region (03) and in the nose region (04).

34. folding former according to claim 5 and one of claims 2 or 6, characterized in that in the leg region (03) and in the nose region (04) mutually different microporous material (09) is provided.

35. folding former according to claim 32 or 34, characterized in that the different microporous material (09), the layer thickness and / or a different pressure for the leg area (03) and the nose area (04) is designed such that an air outlet flow per unit area in the nose area (04) is greater than that in the leg area (03) ,

36. folding former according to claim 5 and 18, characterized in that in the leg region (03) and in the nose region (04) the same microperforation with microbores (12) is provided.

37. folding former according to claim 5 and 18, characterized in that in the leg area (03) and in the nose area (04) from each other different microperforation with micro holes (12) is provided.

38. folding former according to claim 32 or 37, characterized in that the different microperforation, its hole density, its hole diameter and / or a different pressure for the leg region (03) and the nose region (04) is designed such that an air outlet flow per unit area in Nose area (04) is larger than that in the thigh area (03).

39. folding former according to claim 35 or 38, characterized in that the air outlet in the leg area (03) at 2 to 15 standard cubic meters per m ² and that in the nose area (04) is 7 to 20 standard cubic meters per m ² , the latter being always larger than the former.