METHOD, BASIC STRUCTURE, AND PAPER MACHINE CLOTHING

Abstract

A method for thermally fixing a seam loop of a basic structure for a paper machine clothing, such as a seam felt of a paper machine. A flat fabric is provided with longitudinal threads and transverse threads. The flat fabric may have passed through a first thermal fixing process. The flat fabric is folded at at least one folding point to form a two-ply structure and to form a seam loop at the folding point. An electrically conductive pintle wire is inserted into the seam loop and the electrically conductive wire is heated by applying a voltage for thermally fixing the seam loop and for improving a structure of the seam loop.

Claims

1. A method for heat setting a seam loop for a basic structure of a clothing, the method comprising the following steps: a) providing a flat fabric formed with longitudinal threads and transverse threads, the flat fabric having passed through a first heat setting process; b) folding the flat fabric at at least one folding point to form a two-ply structure and to form a seam loop at the at least one folding point; c) inserting a pintle wire into the seam loop, the pintle wire being an electrically conductive pintle wire; and d) heating the electrically conductive pintle wire by applying an electrical voltage and thereby heat-setting and improving a structure of the seam loop.

2. The method according to claim 1, wherein steps b) to d) comprise: folding the flat fabric at two folding points to form a two-ply structure and forming two seam loops at the two folding points, and connecting two end edges of the flat fabric to one another; guiding the two seam loops one inside another and connecting the seam loops by inserting a pintle wire while forming a two-ply fabric loop, and simultaneously heat setting the two seam loops.

3. The method according to claim 1, which comprises forming the at least one folding point by removing a majority of mutually adjacent transverse threads in an area of the folding point.

4. The method according to claim 3, which comprises carrying out the step of removing the mutually adjacent transverse threads between step a) and step b).

5. The method according to claim 1, wherein the electrically conductive pintle wire is a monowire.

6. The method according to claim 5, wherein the monowire has a circular cross section.

7. The method according to claim 1, wherein the electrically conductive pintle wire is a twine or a woven structure made up of multiple yarns.

8. The method according to claim 7, wherein said twine or said woven structure is exclusively formed from electrically conductive yarns.

9. The method according to claim 7, wherein said twine or said woven structure consists of a combination of electrically conductive yarns and non-electrically conductive yarns.

10. The method according to claim 1, wherein the electrically conductive pintle wire is a metallic pintle wire.

11. The method according to claim 1, wherein the electrically conductive pintle wire is a polymer wire, which is made conductive by introducing particles or by coating.

12. The method according to claim 1, which comprises determining a temperature of at least one of the electrically conductive pintle wire or the seam loops with at least one sensor.

13. The method according to claim 12, which comprises using temperature values determined by the at least one sensor for regulating an electrical voltage across the pintle wire.

14. The method according to claim 1, which comprises producing a seam felt of a paper machine.

15. A basic structure for a clothing, wherein the basic structure has been produced by the method according to claim 1.

16. The basic structure according to claim 15, wherein the clothing is a seam felt of a paper machine.

17. A clothing, comprising a basic structure produced by the method according to claim 1.

18. The clothing according to claim 17, configured as a seam felt for a paper machine.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0107] FIGS. 1A to 1D are plan views explaining steps of the method according to one aspect of the invention;

[0108] FIGS. 2A to 2D are similar views explaining steps of a method according to a further aspect of the invention;

[0109] FIGS. 3 and 4 are sectional side views showing seam loops with pintle wires for carrying out method steps according to various aspects of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0110] Referring now to the figures of the drawing in detail and first, in particular, to FIGS. 1A to 1D thereof, there are illustrated steps of a method according to one aspect of the invention. First, a flat fabric 3 is provided here, which is woven from longitudinal threads 4 and transverse threads 5. Such flat fabrics 3 can be produced very rapidly, in contrast to circular weaving. The flat fabric 3 was subjected to a thermal fixing process (heat setting) after the weaving. The tensions in the fabric threads 4, 5 are thus removed, but these fabric threads 4, 5 are also deformed.

[0111] For methods according to diverse aspects of the present invention, fabrics in plain weave can be used as the flat fabric 3. It is also conceivable that one or more parameters of the weaving pattern change at a point of the flat fabric 3. Such a change is reasonably provided at the future folding point.

[0112] In FIG. 1B, several transverse threads 5 have been removed in the surrounding of the folding point or fold. Typically, 3 to 7 transverse threads 5 are removed. Due to the removal of the transverse threads 5, a so-called window 6 forms in the flat fabric 3, in which the flat fabric 3 only has longitudinal threads 4. After the preparation of such a window 6, the flat fabric 3 can be folded, and can be formed into a two-ply structure by laying it on itself. This is shown in FIG. 1c. A seam loop 2 thus forms at the folding point. Due to the removal of the transverse threads 5 and formation of a window 6, the seam loop 2 is essentially formed by longitudinal threads 4. This facilitates the insertion of an insertion wire 1.

[0113] However, the longitudinal threads 4 are still deformed by the heat setting process. Round seam loops aligned in a plane are the basis for good seam tensions, however. These deformations are to be removed again by a further thermal treatmentpossibly in combination with a certain tension in the longitudinal direction.

[0114] In a method according to one aspect of the invention, an electrically conductive pintle wire 1 is inserted into the seam loop 2 for this purpose, as shown in FIG. 1D. An electrical voltage source 11 can then be connected to this electrically conductive pintle wire 2. A current thus flows through the electrically conductive pintle wire 1. The wire 1 acts as a resistance and heats up. The longitudinal threads 4 of the seam loop 2 are heated by the heated pintle wire 1. Deformations in the longitudinal threads 4 can thus be resolved. To optimize the method, it is possible to use a temperature sensor (not explicitly shown in the figure), which monitors the temperature of the seam loop 2. The strength of the electrical voltage 11 can be set on the basis of the determined temperature values. This can take place manually or also in the form of an automated control loop. In this method, the energy is deliberately only introduced in the area of the seam loops 2. On the one hand, energy can thus be saved in comparison to the conventional process. On the other hand, it is especially also possible using the method described in FIGS. 1A to 1D to heat set the seam loops of the loop elements described in U.S. Pat. No. 11,952,717 B2 and its counterpart EP 4010528 A1, which are only present as a short loop element having a seam loop 2, and cannot be connected to form a closed endless band.

[0115] While the method described in FIGS. 1A to 1D is suitable for heat setting a single seam loop, FIGS. 2A to 2D show an alternative embodiment of the method, in which two seam loops 2similarly to the conventional processcan be heat set simultaneously. In FIG. 2A, as in FIG. 1A, a flat fabric 3 is again provided, comprising longitudinal threads 4 and transverse threads 5, wherein the flat fabric 3 in particular has run through a first heat setting process. The flat fabric 3 in particular has twice the length of the later basic structure here. As shown in FIG. 2B, windows 6 are now formed at two points by removing transverse threads 5. These windows 6 have a spacing in the longitudinal direction of the flat fabric 3 which corresponds to the length of the later basic structure. By folding the flat fabric 3 at two folding points in the area of the two windows 6, a two-ply structure results with formation of two seam loops 2 at the respective folding points. The previous end edges of the flat fabric 3 are typically connected to one another, in particular welded.

[0116] As shown in FIG. 2C, the two seam loops 3 can be led one inside the other and connected by means of a pintle wire. A closed, two-ply endless band is thus obtained.

[0117] As shown in FIG. 2D, in methods according to aspects of the invention, the pintle wire can be embodied as an electrically conductive pintle wire 1. It is again provided here that the electrically conductive pintle wire 1 is heated up by applying an electrical voltage source 11 for the heat setting of the two seam loops 2. As can be seen in FIG. 2D, both seam loops 2 are connected here to the electrically conductive pintle wire 1, and are simultaneously heat set by the heating of the electrically conductive pintle wire 1. A temperature sensor can also again be provided here, and the voltage 11 can be regulated on the basis of the measured temperatures.

[0118] The heat setting of the seam loops 2 in the form of a closed endless band can be advantageous, since, for example, desired pre-tension can thus be applied very easily to the seam loops. The formation of the seam loops 2 can thus be influenced within certain limits.

[0119] Various possibilities are available for the design of the electrically conductive pintle wire 1. In principle, it is possible to embody it as a simple metallic monowire 1, in particular having circular cross section. However, this has the disadvantage that in electrical conductors, the resistance decreases with an increasing diameter of the wire, due to which the wire heats up less. This is often disadvantageous, in particular in seam loops 2 having larger loop diameter.

[0120] FIG. 3 shows as a possible alternative an electrically conductive pintle wire 1 which is embodied as a twine 7. The twine 7 consists by way of example of four yarns 8 in FIG. 3, wherein all four yarns 8 are embodied as electrically conductive yarns 8. The yarns shown here are plastic filaments, which are coated with a conductive layer, in particular a metallic layer. This has the advantage that the twine 7 as such is electrically conductive, but the resistance of the twine 7 only decreases insignificantly even at larger diameters, since the individual conductive yarns 8 have an electrically nonconductive plastic core.

[0121] A further possible embodiment of the electrically conductive pintle wire 1 is shown in FIG. 4. In this case, the electrically conductive pintle wire 1 is again embodied as a twine 7 made of four individual yarns. However, the twine 7 consists here of a combination of conductive yarns 8 and non-electrically conductive yarns 9. In the example of FIG. 4, there are two conductive yarns 7 and two nonconductive yarns 9. In general, however, other ratios and also other numbers of yarns 8, 9 are also possible in the twine 7. In this way, it is possible to prevent the resistance of the electrically conductive pintle wire 1 from dropping excessively strongly with increasing diameter. The metallically coated plastic filaments shown in FIG. 3 can again be used here as the electrically conductive yarns 8. Alternatively or additionally, however, other conductive yarns 8 such as, for example, metallic monowires can also be used.

[0122] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: [0123] 1 electrically conductive pintle wire [0124] 2 seam loop [0125] 3 flat fabric [0126] 4 longitudinal thread [0127] 5 transverse thread [0128] 6 window [0129] 7 twine [0130] 8 electrically conductive yarn [0131] 9 non-electrically conductive yarn [0132] 11 voltage source