Clothing and method for producing a clothing

Abstract

A clothing, in particular a drying wire, for a machine for producing a fibrous web, such as a paper or cardboard web, is a planar textile structure from yarns which intersect in a machine direction and in a cross-machine direction. The planar structure has two edges oriented in the machine direction and two edges oriented in the cross-machine direction. The clothing is joinable along the edges oriented in the cross-machine direction in the machine so as to form an endless belt. The clothing is only calendered by introducing energy in peripheral regions which extend along the edges oriented in the machine direction and/or along the edges oriented in the machine cross direction, on account of which in the peripheral regions the MD yarns are welded to the CMD yarns, and the thickness and/or permeability of the clothing are/is reduced.

Claims

1. A clothing for a machine for producing a fibrous web, the clothing comprising: a planar textile structure formed of yarns which intersect substantially perpendicularly and which are substantially oriented in a machine direction and in a cross-machine direction; said planar textile structure having two edges oriented in the machine direction and two edges oriented in the cross-machine direction; seam elements configured to join said planar textile structure in the machine to form an endless belt, said seam elements being disposed at said edges that are oriented in the cross-machine direction and formed by, or connected to, said yarns that are oriented in the machine direction; said planar textile structure having the characteristics of having been calendered by introducing energy only in peripheral regions which extend along said edges that are oriented in the machine direction and along said edges that are oriented in the machine cross direction, or by introducing energy only in the peripheral regions which extend along said edges that are oriented in the machine cross direction, wherein the yarns oriented in the machine direction are welded in the peripheral regions to the yarns oriented in the cross-machine direction and/or are form-fittingly interconnected at intersection points thereof, wherein those regions of said planar structure that have been calendered have a permeability that is reduced relative to those regions that have not been calendered and wherein the peripheral regions that extend along said edges that are oriented in the cross-machine direction have a permeability that is matched to the permeability of those regions that have not been calendered and the matched permeability is due to having been post-perforated while the peripheral regions that extend along said edges that are oriented in the machine direction have the reduced permeability due to having been calendered but not having been post-perforated.

2. The clothing according to claim 1, wherein, in the calendered peripheral regions, the yarns oriented in the machine direction are fused with the yarns oriented in the cross-machine direction and integral therewith.

3. The clothing according to claim 1, wherein, in the calendered peripheral regions, the yarns oriented in the machine direction are welded to the yarns oriented in the cross-machine direction, while maintaining a cross-sectional shape thereof.

4. The clothing according to claim 1, wherein a thickness of the calendered peripheral regions, relative to an original thickness in a non calendered state, is reduced by the calendering by a proportion of between 5% and 50%.

5. The clothing according to claim 1, wherein a permeability in the peripheral regions that have been calendered but not post-perforated, relative to a permeability of the planar structure outside the calendered peripheral regions, is reduced by the calendering by 5 to 100%.

6. The clothing according to claim 1, wherein a width of the calendered peripheral regions is between 5 mm and 50 mm.

7. The clothing according to claim 1, wherein an extraction force required for extracting yarns oriented in the cross-machine direction in relation to the planar textile structure having non-calendered peripheral regions is increased by at least 10%.

8. The clothing according to claim 1, wherein the calendering is effected unilaterally or bilaterally on a side configured to face a fibrous web and/or on a side configured to face the machine.

9. The clothing according to claim 1, wherein said seam elements are seam loops on at least one of said edges oriented in the cross-machine direction, said seam loops being formed by reverse interweaving of at least some of the yarns oriented in the machine direction with the planar structure, and at least some reverse-interwoven portions of at least some of the yarns oriented in the machine direction are welded to yarns oriented in the cross-machine direction and/or to yarns oriented in the machine direction in the calendered peripheral regions of the at least one edge oriented in the cross-machine direction.

10. The clothing according to claim 1, wherein said seam elements are helices or structures which are independent of said planar textile structure and which are releasably or non releasably disposed on at least one peripheral region of one of said edges oriented in the cross-machine direction.

11. The clothing according to claim 10, wherein said seam elements having the planar textile structure are non-releasably disposed on said at least one peripheral region by at least one process selected from the group consisting of adhesive bonding, stitching, welding, and interlocking.

12. The clothing according to claim 10, wherein, on account of the welding of the yarns by way of calendering of the peripheral regions oriented in the cross-machine direction, the yarns oriented in the cross-machine direction are load-bearing.

13. The clothing according to claim 10, wherein, on the at least one peripheral region of the edge oriented in the cross-machine direction, a thickness of the planar structure in relation to outside the peripheral region is reduced, on account of which, when viewed in the thickness direction of the planar structure, the upper side and/or lower side of the planar structure in the calendered peripheral region is recessed in relation to outside the calendered peripheral region, and the seam elements are disposed on the recessed side of the upper side and/or lower side.

14. The clothing according to claim 9, wherein the edges of the clothing are inter-connectable by mutual interleaving of said seam elements on the edges oriented in the cross-machine direction and by inserting at least one pintle in a duct formed by the interleaved seam elements.

15. The clothing according to claim 1, wherein said yarns forming said planar textile structure are configured as monofilaments or multi filaments.

16. A method for producing clothing according to claim 1, wherein the method comprises the following method steps: i) providing a clothing with yarns oriented in the machine direction and yarns oriented in the cross-machine direction; ii) cutting the clothing along a predefined cutting line in the machine direction and/or in the cross-machine direction; iii) fusing ends of the yarns oriented in the machine direction and/or fusing ends of the yarns oriented in the cross-machine direction with the yarns oriented in the machine direction, so as to configure a smooth cutting edge.

17. The method according to claim 16, which comprises carrying out the method by way of a device for introducing energy selected from the group consisting of a rotating disk-shaped ultrasonic horn and of a hot wedge.

18. The method according to claim 16, which further comprises: iv) surface calendering the peripheral regions which are configured bilaterally so as to adjoin the cutting edges; and thereby carrying out method step iv) simultaneously with method steps ii) and iii).

19. The method according to claim 18, wherein method step vi) is carried out by way of an additional device for introducing energy, which is guided in a parallel manner.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The FIGURE shows a highly schematic illustration of a clothing configured according to the invention, in a perspective illustration.

(2) A clothing 1 which may be used in particular as a drying wire in a machine for producing a fibrous web, such as a paper web or cardboard web, is illustrated in a schematic illustration in the FIGURE.

DESCRIPTION OF THE INVENTION

(3) Woven drying wires as in the illustrated exemplary embodiment are often employed in the mentioned application. A further embodiment may be produced from wound helices which are mutually interleaved and interconnected by pintles. This embodiment is not the subject matter of the present invention.

(4) In order to maintain clarity, only part of the drying wire face in the FIGURE is illustrated as a woven fabric from mutually intersecting yarns 2, 3. The yarns 2, 3 may be configured in a known manner as monofilaments or multifilaments in any cross-sectional shape from PET, PPS, PCTA, polyamides, Kevlar or similar materials which are suitable and known for the mentioned application.

(5) The clothing 1 is configured in the form of a planar textile structure which two edges 4 which are oriented in a machine direction (hereunder referred to as MD) and two edges 5 which are oriented in a cross-machine direction (hereunder referred to as CMD).

(6) In the machine, the clothing 1 is closable to form a closed loop by using seam elements 6. The seam elements 6 here may be configured so as to be integral with the clothing 1 or be provided as separate components which are embodied so as to be releasable or non-releasable on the clothing 1.

(7) In the first case, some or all of the yarns 2 oriented in the MD are folded back and reverse interwoven, such that seam loops are configured at the end on one or both edges 5 in the CMD. Said seam loops a joinable so as to form an endless belt by mutual interleaving and subsequent insertion of a pintle 8 into the duct formed by the seam loops.

(8) Alternatively, the seam elements 6 may also be configured in the form of separate components, for example in the form of helices which at one or both edges 5 may be connected in a suitable manner to the planar textile structure. The connection here may be designed to be releasable or non-releasable. Adhesive bonding, welding, stitching or similar may be used.

(9) It is likewise possible for a hybrid form of the seam element 6 to be attached to the two edges 5, that is to say seam loops to one edge 5 and a separate component to the other edge 5.

(10) According to the invention, the clothing 1 in the peripheral regions 7 which extend along the edges 4, 5 is treated by suitable measures, in particular by calendering, such that permeability and/or thickness of the clothing 1 is reduced in relation to the non-treated state.

(11) The width of the peripheral regions 7 here may be 5 to 50 mm. The reduction in thickness is preferably 5 to 50%, particularly preferably 10 to 30% of the original thickness of the clothing 1.

(12) A reduction in permeability of the clothing 1 by way of calendering is 5 to 100%, preferably between 30 and 100%. As can be appreciated, the reduction in permeability in the calendered peripheral regions 7 which are configured on edges 4 oriented in the machine direction is greater than in the calendered peripheral regions 7 which are configured along the edges 5 oriented in the cross-machine direction. The reason therefor is that there is no fibrous web running in the regions 7 oriented in the machine direction, and, correspondingly, the reduction in permeability here is not furthermore appreciable in terms of the quality of the final product. This in contrast to the calendered peripheral regions 7 oriented in the cross-machine direction, which are used for forming the seam. It is reasonable here to strive for permeability which substantially corresponds to that displayed by the remaining clothing 1, that is to say outside the calendered peripheral regions. In order for permeability to be set to a specific value, perforation to the desired extent may also be performed post-calendering and consequential compacting of the peripheral regions 7. This is particularly reasonable in the cross-machine direction if and when compacting has been very intense and permeability has been excessively restricted.

(13) The peripheral regions 7 here may for example be calendered by introducing energy in the form of electromagnetic radiation, thermal radiation, or similar. The introduction of energy may be performed by way of an ultrasonic device, in particular by way of an ultrasonic horn, a laser device, a hot wedge device, or similar devices.

(14) The yarns 2, 3 are interconnected on account of the introduction of energy, since said yarns 2, 3 are heated and softening of the material arises on account thereof, resulting in an improved form-fit of the yarns 2, 3, on the one hand. On the other hand, materially-integral bonding, that is to say fusing, of the yarns 2, 3 may also be performed to some extent. Here, yarns 2 oriented in the MD are welded to yarns 3 oriented in the CMD, and yarns 2, 3 oriented in the respective direction are welded to one another as well. Connecting the yarns here is performed under the proviso that the introduction of energy is kept sufficiently low so as not to lead to brittleness in the material. Furthermore, the selected cross-sectional shape of the yarns 2, 3 should be maintained post-calendering.

(15) Calendering here may be performed unilaterally on that side of the clothing 1 that faces the fibrous web or the machine, as well as bilaterally on each of the edges 4, 5.

(16) The mentioned measures are advantageous in many respects. On the one hand, an edge finish which prevents the yarns 2, 3 from being released from the planar textile structure and prevents the latter from being able to unravel may be achieved by way of the introduction of energy. In particular, it is possible for the extraction force which would be required for yarns 3 oriented in the cross-machine direction to be extracted from the woven fabric to be increased by at least 10% in relation to a clothing 1 having non-calendered peripheral regions 7. On account thereof, damage to the clothing 1 as well as to the machine may be prevented, and the service life of the clothing 1 may additionally be increased.

(17) On the other hand, calendering of the edges 4 oriented in the machine direction permits structuring of the peripheral regions 7, on account of which it is possible for influence to be exerted on the aerodynamics of the clothing 1.

(18) On account of calendering the edges 5 oriented in the CMD, it is moreover possible for the seam elements 6 to be configured in a more effective manner and to be fixed in a simpler and more reliable manner.

(19) In the case of seam loops which have been created by reverse interweaving of yarns 2 in the planar textile structure, the length of the reverse interwoven yarns 2 may be reduced to a comparatively short distance, permitting faster production of the clothing 1. Moreover, stability of the seam loops is improved, since a connection between the yarns 2, 3 is established by calendering, reducing the risk of the reverse interwoven yarns 2 being extracted.

(20) Calendering is also advantageous for fixing a separate seam element 6 to the extent that the calendered peripheral regions 7 are more stable and a separate seam element 6 may thus be fixed in a more reliable manner than to a non-calendered edge 5 of a clothing 1. Fraying of the yarns 3 oriented in the CMD in this instance is almost impossible, since there is a form-fitting and materially-integral connection between the yarns 2 and 3. On account of the interconnection between the yarns 2 and 3 it is possible for the yarns 3 oriented in the cross-machine direction to be designed in a load-bearing manner, without requiring seam loops to be configured. This load-bearing ability is enabled on account of welding by way of calendering. The tensile force acting on the clothing 1 in the state thereof when installed in the machine may thus be diverted to the yarns 3 oriented in the cross-machine direction. Consequently, separate seam elements 6 may be reliably fastened without the yarns 3 oriented in the cross-machine direction being ripped out under load.

(21) Furthermore, the reduction in thickness of the clothing 1 in the region of the edges 5 is advantageous when the seam elements 6 are present as separate components and are fixed to the clothing 1. Components of this type require space in the thickness direction of the clothing 1. When the peripheral region 7 on account of calendering is thus no longer as thick as the remaining part of the clothing 1, that is to say as the non-calendered region, a seam element 6, for example a clip, may be fastened to the edge 5 without the clothing 1 becoming thicker on account thereof.

(22) A further alternative embodiment lies in that a tape-shaped component is disposed as a seam element 6 either on the one or on the other side of the clothing 1. On account thereof, it may be prevented that undesirable noise emissions arise by way of the seam element 6 impacting on the drying cylinder of the paper machine or cardboard machine, for example. The marking tendency in the fibrous web as well as the abrasion tendency is likewise reduced on account thereof.

(23) Production of the clothing 1 may be performed in a simple and time-saving manner at low complexity, since calendering may be performed simultaneously with the preparation of the clothing 1. The clothing 1 here is present as a flat-woven fabric which has to be tailored in terms of length and width to the position where it will be employed. The steps required to this end may be carried out by means of an ultrasonic horn, for example, in particular by means of a rotating disk-shaped ultrasonic horn, or by a hot wedge. The clothing 1 here is cut to the required dimensions (optionally including some allowance to compensate for shrinkage), and the edges 4, 5 are simultaneously trimmed, so that fraying or unraveling is no longer possible. The ends of the yarns 2, 3, or the yarns 3, 2 which in each case run transversely to the former, are welded to one another here. Calendering as has been described above may optionally be performed in a further operational step or particularly preferably be performed in the same operational step as cutting and trimming in that a second apparatus for introducing energy is guided in a parallel manner with the ultrasonic horn or the hot wedge, calendering the peripheral regions 7. The second apparatus may likewise be an ultrasonic horn, a hot wedge, a laser, or another suitable source for introducing energy.

(24) The clothing 1 which has been prepared in this manner, on the edges 5 oriented in the CMD, may now be provided with seam elements 6 which, as described further above, may be configured as clips which are attachable to the edges 5 and may be welded to the edges 5, for example.

(25) If and when the seam loops are to be created by reverse interweaving, it is reasonable for the seam loops to be formed first and for calendering for stabilizing the seam loops to be carried out subsequently.

(26) The invention is not limited to the exemplary embodiment illustrated. In particular, a wide choice of weaving patterns and various materials for the yarns 2, 3 are conceivable and possible.