METHOD FOR PRODUCING A BASE STRUCTURE FOR A PAPERMACHINE CLOTHING

Abstract

A method for producing a base structure of a clothing for use in a machine producing and/or processing a fiber web. The clothing base structure is a laminate formed of at least two layers and the layers are formed substantially from polymer material. The method includes the following steps: locally melting the polymer material of the two layers by the action of radiation from a radiation source and pressing the polymer material of the two layers onto each other. The polymer material of the two layers is thereby guided into a press nip formed by two press rolls, forming an inlet gap, and the radiation is directed into the inlet gap.

Claims

1-15. (canceled)

16. A method for producing a base structure of a clothing for use in a machine for producing and/or processing a fibrous web, the clothing base structure having a laminate formed from at least two layers, which are formed substantially from polymer material, the method comprising: locally melting the polymer material of the at least two layers by irradiation from a radiation source to form molten polymer material; guiding the at least two layers into a press nip formed between two pressing rolls, the press nip having a run-in gap, and pressing the molten polymer material of the two layers together in the press nip between the pressing rolls; and directing the radiation of the radiation source into the run-in gap.

17. The method according to claim 16, which comprises producing one of the at least two layers as a first band-shaped film strip, a width of which is smaller than a width of the base structure of the clothing to be produced, and helically winding the strip around two mutually spaced-apart winding rolls.

18. The method according to claim 17, which comprises producing another of the at least two layers as a second band-shaped film strip, a width of which is smaller than the width of the clothing base structure to be produced, and helically winding the strip around two mutually spaced-apart winding rolls, and, at the same time, laminating the second band-shaped film strip onto a first layer formed by the first band-shaped film strip.

19. The method according to claim 18, wherein side edges of the first band-shaped film strip run parallel but offset with respect to the side edges of the second band-shaped film strip.

20. The method according to claim 18, wherein side edges of the first band-shaped film strip do not run parallel with respect to side edges of the second band-shaped film strip.

21. The method according to claim 18, wherein two mutually adjacent side edges of the helically wound first band-shaped strip and/or second band-shaped film strip have no direct force-fitting, form-fitting, or cohesive connection to one another.

22. The method according to claim 18, wherein the two winding rolls for winding the first band-shaped film strip are identical to the two winding rolls for winding the second band-shaped film strip.

23. The method according to claim 22, wherein one of the two winding rolls is identical to one of the two pressing rolls.

24. The method according to claim 16, wherein, for connecting the two layers, no auxiliary substances are introduced between the layers.

25. The method according to claim 24, wherein no adhesive and/or any material that is absorbent for the radiation is introduced between the layers.

26. The method according to claim 24, which comprises connecting the layers without introducing soot therebetween.

27. The method according to claim 16, wherein the polymer material of the first layer differs from the polymer material of the second layer.

28. The method according to claim 27, wherein the polymer material of the first layer is formed substantially from polyamide, and the polymer material of the second layer is formed substantially from polyethylene terephthalate.

29. The method according to claim 28, which comprises arranging the first layer radially inside relative to the second layer in the finished clothing base structure.

30. The method according to claim 28, wherein the first layer has a different visual characteristic from the second layer.

31. The method according to claim 28, wherein the first layer has a different color than the second layer.

32. The method according to claim 16, which further comprises forming the laminate formed of at least two layers with a multiplicity of passage openings.

33. A clothing for a machine that produces and/or processes a fibrous web, the clothing comprising: a base structure which has been produced by the method according to claim 16.

34. The clothing according to claim 33, wherein said clothing base structure has a laminate of at least two layers, each of said at least two layers being formed of a helically wound band-shaped film strip, and said two layers being areally fused to one another, with no auxiliary substances present between said at least two layers.

35. The clothing according to claim 34, wherein said band-shaped film strips have side edges, and two side edges of a respective band-shaped film strip have no direct force-fitting, form-fitting or cohesive connection to one another.

Description

[0024] The invention will be discussed in more detail below on the basis of schematic drawings, which are not true to scale. In the drawings:

[0025] FIG. 3 is a schematic illustration of a device for producing a clothing base structure,

[0026] FIG. 4 is a first embodiment of a clothing base structure,

[0027] FIG. 5 is a second embodiment of a clothing base structure.

[0028] FIG. 3 shows a device for carrying out the method according to the invention for producing a base structure 8 of a clothing for use in a machine which produces and/or processes a fibrous web. The clothing may for example be the forming screen of a paper-making machine. The device comprises, as main elements, three rolls, specifically a first winding roll 14, a second winding roll 15 and a first pressing roll 16, and a radiation source 18, for example a laser. In the case of this arrangement, the first winding roll 14 simultaneously functions as a second pressing roll. The respective direction of rotation of the three rolls 14, 15, 16 during intended use is indicated by a curved arrow, and the respective axis of rotation thereof is indicated by a cross, in FIG. 3.

[0029] In a first process step, the first pressing roll 16 is however not yet required. In this method step, a first band-like film strip 20 is wound helically around the two winding rolls 14 and 15 until the desired width of the clothing base structure 8, which may substantially correspond to the width of the final clothing, has been attained. For variation of the desired length of the clothing base structure 8, the spacing between the two winding rolls 14, 15 can be varied. In this way, a first, radially inner layer for a laminate of the clothing base structure 8 to be produced is formed. This first layer has substantially the same appearance as the arrangement described with regard to FIG. 2, wherein the laminate 12 is however to be imagined as having been replaced by the first band-like film strip 20.

[0030] At this juncture, it is pointed out once again that the figures are purely schematic illustrations. In reality, the spacing between the winding rolls 14, 15 may be considerably greater, and the width of the laminate 12 or of the band-like film strip 20 may be considerably smaller, such that the two winding rolls 14, 15 are enwound with a significantly greater number of windings than that illustrated in the figures. It is also possible for the angle with which winding is performed, that is to say the angle between side edge 22 (see FIGS. 4 and 5) and the axis of rotation of one of the two winding rolls 14, 15 to be different, in particular smaller.

[0031] The first band-like film strip 20 is preferably an extruded polyamide film with a substantially monolithic structure. Here, it is itself thus not a laminate comprising multiple layers, as in WO 2015/185278 A1, wherein this would also be possible.

[0032] In a second process step, a second layer is laminated onto the first layer radially at the outside. The second layer is in this case composed of a second band-like film strip 24, which is likewise wound helically by means of the two winding rolls 14, 15. During the winding of the second band-like film strip 24, the polymer material of the first layer and the polymer material of the second band-like film strip 24 which forms the second layer are locally melted at their respectively facing surfaces and are immediately subsequently pressed against one another in order to fuse together and thus form a laminate. Said surfaces come into contact with one another in a press nip 28 formed by the two pressing rolls 14, 16, where said surfaces are pressed against one another with a predetermined force. The polymer material is melted at said surfaces by radiation, in particular laser radiation, from the radiation source 18. Said radiation source is positioned such that the radiation is, according to the invention, directed into a run-in gap 17, that is to say into the gap which is formed by the first layer and the second band-like film strip 24 which forms the second layer, which gap opens out in the press nip 28. In the present exemplary embodiment, the radiation, illustrated by arrows in FIG. 3, from the radiation source 18 is, with regard to its main radiation direction, oriented substantially orthogonally with respect to an imaginary plane which comprises the axes of rotation of the two press rolls 14, 16. The radiation thus passes exactly locally to the location where it is required.

[0033] The second band-like film strip 24 may in this case be wound around the two winding rolls 14, 15 such that its side edges 26 run parallel but with a spacing with respect to the side edges 22 of the first band-like film strip 20 of the first layer, as illustrated in FIG. 4. Alternatively, the second band-like film strip 24 may however also be wound around the two winding rolls 14, 15 such that its side edges 26 do not run parallel to the side edges 22 of the first band-like film strip 20 of the first layer but rather cross these, as illustrated in FIG. 5. In FIGS. 4 and 5, the first band-like film strip 20 is illustrated, by way of its side edges 22, only using dashed lines, because it is concealed by the second band-like film strip 24 which forms the second layer.

[0034] The two side edges 22 of the first band-like film strip 20 preferably lie together in a butt-jointed manner without being directly connected to one another in form-fitting, force-fitting or cohesive fashion. Likewise, it is preferable for the two side edges 26 of the second band-like film strip 24 to lie together in a butt-jointed manner without being directly connected to one another in form-fitting, force-fitting or cohesive fashion. The two band-like film strips thus remain in their wound form by virtue of the two layers being laminated areally on one another.

[0035] The second band-like film strip 24 is preferably an extruded polyethylene terephthalate film with a substantially monolithic structure. Thus, the second layer of the laminate is composed of a different polymer material than the first layer. In this way, it is possible for different material characteristics to be advantageously combined in the laminate. Furthermore, the two layers may be differently pigmented in order to function as a wear indicator. The two layers preferably have a layer thickness of 500 m or less. The total thickness of the base structure amounts to preferably 1200 m or less. The two film strips may be stretched, preferably in their main extent direction, in order to increase the strength. Furthermore, the laminate may also comprise more than two layers, wherein a third layer may be applied to the second layer in substantially the same way as the second layer was applied to the first layer. The same applies to all further layers.

[0036] After the completion of the laminate, this may also be provided with a multiplicity of passage bores which provide the base structure with the capability of draining a fibrous web transported on the finished clothing. The passage bores may for example be introduced by punching or by boring. For the latter, the use of a laser is particularly favorable.

LIST OF REFERENCE DESIGNATIONS

[0037] 1a, 1b, 1c Polymer films [0038] 8 (Clothing) base structure [0039] 9 Radiation source [0040] 10, 11 Pressing rolls [0041] 12 Laminate [0042] 14, 15 Winding rolls [0043] 16 Pressing roll [0044] 17 Run-in gap [0045] 18 Radiation source [0046] 20 First band-like film strip [0047] 22 Side edge of the first band-like film strip [0048] 24 Second band-like film strip [0049] 26 Side edge of the second band-like film strip [0050] 28 Press nip