Method, basic structure and paper machine clothing

Abstract

The invention relates to a method for thermally fixing a seam loop of a basic structure for a paper machine clothing, in particular for a seam felt of a paper machine, the method comprising the steps: a. providing a flat fabric comprising longitudinal threads and transverse threads, the flat fabric in particular having passed through a first thermal fixing process; b. folding the flat fabric to form a two-ply structure at at least one fold location so as to form a seam loop at the fold location; c. inserting a pintle wire into the seam loop, characterized in that d. the pintle wire is formed as an electrically conductive pintle wire, and the electrically conductive pintle wire is heated by applying a voltage for thermally fixing the seam loop.

Description

[0001] Process, basic structure and covering

[0002] The invention relates to a method for producing a base structure for a paper machine clothing, in particular for a seamed felt. Furthermore, the invention relates to the produced base structure and a clothing comprising such a base structure.

[0003] Woven structures are often used in paper machine clothing. For example, press felts typically comprise a woven base structure (ground weave) to which one or more layers of nonwoven fibers are attached.

[0004] For a long time, it was necessary to produce a circularly woven, endless fabric loop, which required a complex and lengthy weaving process. To avoid endless weaving, Sudre presented a process in EP0425523 in which the two ends of a flat fabric are folded over themselves, creating a two-layer fabric piece. The two front edges of the fabric piece are usually joined together in a suitable manner. Seam loops are created at the folds, which can be inserted into each other and connected with a pintle wire. This creates a fabric loop with a pintle wire seam, which can serve as the basic structure for a seam felt.

[0005] As an improvement to this process, EP2788546 B1 proposed removing some transverse threads from the fabric at the fold points. This creates larger seam loops, which significantly facilitate the formation of the pintle seam.

[0006] A further development of this is known from patent DE 10 2019 121 485. The basic structure is constructed from several modules, with each of the two seam loop modules created by folding a flat fabric once. These seam loop modules are then typically joined with additional flat fabric pieces to form the two-layer fabric. This enables more economical production, as the fabrics and seam elements can be manufactured independently of the dimensions of the subsequent covering.

[0007] In the production of the structures described above, the flat fabrics are usually thermally pre-set on a setting device downstream of the loom. This relieves tensions in the fabric threads created during weaving and also deforms the threads. A fabric thread removed from the fabric after pre-setting is then no longer straight, but has a wavy shape.

[0008] If seam felts are to be made from these fabrics, the fabric is first joined to form a continuous tape and weft threads or cross threads are usually removed at two points on the fabric tape. The seam loops for the pintle seam are formed at these points. The seam area is often secured with a stitched seam. However, the seam loops formed in this way from the threads / monofilaments running in the machine direction still exhibit the waves or crimps caused by the fixing of the fabric structure, which only partially permit the formation of a functioning pintle seam. In practice, the pintle seam of the fabric is closed with a pintle wire provided for this purpose and the entire fabric is heat-set again in a second fixing process.This allows the deformations caused by the fabric crimping to be removed, resulting in cleanly formed suture loops that are adapted to the cross-section of the pintle wire. This allows for comparatively easy opening and closing of the pintle wire suture.

[0009] This re-fixing process is carried out on a stretching system with rollers under tension and requires the lengthy heating of at least one oil-heated roller to temperatures of up to 140-170°C. The process takes approximately 30-60 minutes for a single fabric, plus approximately 30 minutes of setup time. This process involves high energy consumption and places a high load on the heat-fixing equipment.

[0010] In addition, during this process, certain areas of the seam loops are subject to different thermal conditions depending on whether they are located on the near or far side of the heated roller. This leads to inhomogeneities in the material properties of the seam loops.

[0011] The object of the invention is to further improve the manufacturing process known from the prior art.

[0012] It is a particular object of the invention to reduce the energy required for production.

[0013] It is a further object of the invention to increase the productivity of an existing machine park in the production of the described structures.

[0014] Finally, it is an object of the invention to improve the quality of the seam loops.

[0015] These objects are achieved according to the invention by a method according to independent claim 1, as well as by the resulting basic structure and a covering using such a basic structure.

[0016] Further advantageous embodiments of the present invention can be found in the subclaims.

[0017] With regard to the method, the object is achieved by a method for the thermal fixing of a seam loop of a basic structure for a clothing, in particular for a seam felt of a paper machine, comprising the steps a. providing a flat woven fabric comprising longitudinal threads and transverse threads, wherein the flat woven fabric has in particular undergone a first thermal fixing process, b. folding the flat woven fabric into a two-layer structure at at least one folding point to form a seam loop at the respective folding point, c. inserting a pintle wire into the seam loop According to the invention it is further provided that d. the pintle wire is designed as an electrically conductive pintle wire, and the electrically conductive pintle wire is heated by applying an electrical voltage for the thermal fixing of the seam loop.

[0018] The inventors have recognized that the thermal setting of the fabric in the second setting step is not essential for the functionality of the basic structure. The second setting step merely serves to improve the structure of the seam or the seam loops. Thus, the heating of the basic structure can also be limited to the area of ​​the seam loops. This makes it possible to fundamentally change the heating process. Instead of applying the energy to the seam loops from the outside via heated rollers, as was previously the case, in the method according to the present invention the energy is introduced into the seam loop from the inside. This is done by means of an electrically conductive pintle wire that is inserted into the seam loop. By applying a voltage, a current flows through this pintle wire, which heats the pintle wire and thus also the threads of the surrounding seam loop(s).

[0019] The heat generated in this way spreads largely evenly throughout the seam loops, as the pintle wire runs centrally within the seam loops. Since the current flow through the conductor is constant at all points, the same electrical heat loss is generated at every point along the entire pintle wire, assuming a constant resistance along the wire length. This essentially enables a very localized, homogeneous heat distribution within the seam loops, as well as uniform and simultaneous heating of all seam loops of the pintle wire seam.

[0020] In this way, the deformations caused by the fabric crimping can be removed and cleanly formed suture loops are obtained that are adapted to the cross-section of the pintle wire.

[0021] In contrast to the prior art, the lengthy heating of at least one oil-heated roller to temperatures of up to 140-170°C is eliminated. The process time for a fabric is reduced from 30-60 minutes plus approximately 30 minutes of setup time to just a few minutes. Thus, the time for the thermal treatment in processes according to the present invention is usually between 90 seconds and 10 minutes, in particular between 2 minutes and 5 minutes. Furthermore, the process proposed within the scope of the invention requires only a fraction of the energy, since heating the heated rollers is dispensed with.

[0022] The described process is particularly advantageous when using fabrics with two different fabric types, where the transition between the fabric types occurs in the area of ​​the pintle seam. Such structures are described, for example, in US 2009 / 0090425. With the heat-setting processes used previously, the fabrics would have to be joined together to form an endless belt and then heat-set with a closed pintle seam. With two different fabric types within one belt, this leads to the problem that the heat-setting process cannot be optimized for both fabric types simultaneously.

[0023] Methods according to aspects of the present invention can be carried out both for individual seam modules, as described in DE 10 2019 121 485, and for an entire two-layer fabric loop, as known, for example, from EP2788546 B1. In the second case, it is advantageous if steps b. and c. are carried out as follows: b. Folding the flat fabric into a two-layer structure at two fold points, forming two seam loops at the respective fold points, and connecting the two front edges of the flat fabric to each other. c. Interleaving the two seam loops and connecting them by inserting a pintle wire to form a two-layer fabric loop,

[0024] Both seam loops can be thermally fixed simultaneously. Advantageously, the closed pintle wire seam can be slightly tensioned in the longitudinal direction (=machine direction) during the thermal treatment. This improves the contact between the seam loops and the conductive pintle wire.

[0025] Keeping the fabric wide in the seam area during thermal setting is also sometimes advantageous and can be achieved by clamping the fabric edges.

[0026] Alternatively, it is also possible in principle to treat the respective fabric ends equipped with seam loops separately by inserting the conductive pintle wire into the seam loops present at the fabric end and carrying out the thermal treatment of the seam loops while the seam is not closed.

[0027] In general, it is advantageous if the method further comprises step a2. Removing a plurality of adjacent transverse threads in the region of the folds

[0028] In particular, step a2 can be performed between steps a and b.

[0029] By removing the cross threads, the position of the fold is clearly defined and made visible, which simplifies the subsequent folding.

[0030] The resulting window also creates larger seam loops, which, among other things, makes it easier to insert the pin wire.

[0031] By adjusting the electrical voltage, the current and thus the heat loss and consequently the temperature of the plug wire can be adjusted very easily and precisely.

[0032] However, for most conductive pintle wire materials, the electrical resistance will increase with increasing temperature. When using such pintle wires, the temperature of the pintle wire or the seam loops can be controlled by temperature-monitored voltage regulation, thus enabling a temperature program to be implemented during the thermal treatment.

[0033] Thus, it may be advantageous that at least one sensor is provided to determine the temperature of the electrically conductive pintle wire and / or the seam loops, wherein the determined temperature values ​​are used in particular to regulate the electrical voltage.

[0034] Contactless infrared sensors, for example, are suitable for this purpose.

[0035] A method according to one aspect of the present invention also makes it possible to have a defined temperature heating and cooling ramp before and after the thermal treatment at the target temperature. This is not possible or only possible to a limited extent with the methods known from the prior art. Although the heating rollers can be operated with predetermined temperature profiles in the prior art - limited by the inertia of the roller temperature. However, the base fabric must be moved over the hot roller and thus cools down with each revolution and heats up again upon renewed contact with the heating roller. If the thermal treatment is carried out in one belt revolution, the heating and cooling ramp is also fixed and the fabric cools down after leaving the hot roller, influenced by the ambient temperature.

[0036] In particular, the cooling rate has a strong influence on the morphology of the material after thermal treatment and a targeted control of the cooling ramp enables the material parameters in the seam loops to be optimized.

[0037] In methods according to aspects of the invention, cooling can be achieved very precisely by reducing the voltage—if necessary, monitored by a temperature measurement. Alternatively, plug-in wires with largely temperature-independent resistance can be used, such as constantan wires, or twisted or stranded wires containing constantan wires. In this case, temperature monitoring may be dispensed with.

[0038] For the purposes of this application, the term "wire" or "pin wire" should be understood very broadly. As is common in the field of paper machine clothing, the term is used not only for metallic wires but also for "plastic wires," i.e., stronger plastic filaments.

[0039] In methods according to various aspects of the invention, the electrically conductive plug wires can be realized in different ways.

[0040] For example, it is possible that i. the electrically conductive pin wire is designed as a metallic pin wire. ii. the electrically conductive pin wire is designed as a metallic pin wire that has a polymer coating. iii. the electrically conductive pin wire is designed as a polymer wire that is coated with conductive material, in particular metal. iv. the electrically conductive pin wire is designed as a polymer wire that comprises conductive particles. v. the electrically conductive pin wire is designed as a polymer wire that comprises or consists of electrically conductive polymers.

[0041] Suitable metals for a pintle wire or a coating are, for example, copper, silver, gold or alloys, in particular alloys such as Konstanten®, Manganin® or Isotan®, where the electrical resistance changes only slightly with temperature.

[0042] Suitable polymers for a polymer wire include polyamides or PET. Ideally, such polymers have a melting point significantly above the temperature used for thermally treating the seam loops. The material chosen for the pintle wire is independent of its structure.

[0043] For example, it is possible that

[0044] I. the electrically conductive pin wire is a monowire which in particular has a circular cross-section

[0045] II. the electrically conductive pintle wire is designed as a thread made of several yarns, whereby the thread can in particular be formed exclusively from electrically conductive yarns or can consist of a combination of electrically conductive yarns and non-electrically conductive yarns.

[0046] III. The electrically conductive pintle wire is designed as a braided structure, in particular as a stranded wire or cord, wherein the braided structure can in particular be formed exclusively from electrically conductive yarns or can consist of a combination of electrically conductive yarns and non-electrically conductive yarns.

[0047] IV. The electrically conductive pintle wire is designed as a twine or braided structure, whereby the individual strands are not electrically conductive, but the twine or braided structure as a whole is coated with a conductive material, in particular a metal.

[0048] The electrically conductive pintle wire can be made up of conductive individual threads or pre-twisted yarns. However, the twisted or stranded wire can also contain non-conductive individual threads.

[0049] Likewise, conductive filaments can be made entirely of electrically conductive material or contain a portion of a polymer. For example, the filaments can be constructed of a polymer with conductive material added inside or in the form of a coating, or they can consist of a metal filament coated with a polymer.

[0050] By making part of the pinout wire cross-section non-conductive, the effective cross-section of the conductive material in the pinout wire and thus the electrical resistance of the pinout wire can be adjusted. This prevents excessive resistance and the associated high current flow with larger pinout wire diameters.

[0051] Whether the electrically conductive pintle wire is made entirely of conductive material or not can also be selected depending on the desired diameter of the seam loop, and thus on the required diameter of the pintle wire. Typical pintle wire diameters are between 0.2 and 2.5 mm, preferably 0.5 and 2.0 mm.

[0052] Many aspects play a role in selecting an optimal electrically conductive pintle wire, and ideally at least some of these, and ideally all, should be met. i. The diameter of the pintle wire should be close to the diameter of the seam loop. Typically, these diameters of the seam loops – and thus also of the pintle wires – are between 1.1 mm and 1.8 mm, especially 1.55 mm. ii. The resistance of the pintle wire should be between 0.5 O / m and 200 O / m at room temperature, and particularly between 1 O / m and 50 O / m. iii. The pintle wire should be able to withstand bending stresses without undergoing plastic deformation. This is important to avoid kinks in the seam. iv. Integrity of the pintle wire. The pintle wire should act as a unit, even if it is composed of a large number of individual yarns. A well-known problem is the formation of wire nests.In this case, individual strands of the pintle wire twist or tangle and form nests or knots. This makes it more difficult to pull in and remove the pintle wire. v. The tensile strength of the pintle wire should be greater than 50N, in particular greater than 100N. This is advantageous because, after the heat treatment of the seam loop, the pintle wire can then be easily pulled out again without the risk of the pintle wire tearing and parts remaining in the seam loop, which would then have to be removed at great expense. vi. The material should remain stable over a wide temperature range, for example between room temperature (20°C) and 190°C. In this context, “stable” means that properties such as deformation, dimensional stability, conductivity or state of aggregation do not change or change only slightly.

[0053] These properties cannot be achieved with simple monowires.

[0054] • A simple metallic wire made of NiCr with, for example, a diameter of 1.55 mm fulfills i. and ii., but not iii. (kinks!)

[0055] • A polymer monofilament, on the other hand, cannot easily provide the electrical conductivity properties

[0056] Therefore, a more complex structure of the pin wire is usually useful.

[0057] An improvement to a metallic monowire could, for example, consist of using a metallic twisted or rope-like pintle wire made of a multitude of thinner metal threads. This increases the flexibility of the resulting pintle wire. For ease of reading, the term "twisted wire" will always be used in this application, unless otherwise stated, to also refer to structures with multi-stage twisting, such as rope-like structures.

[0058] Possible rope-like pin wires made of metal filaments are

[0059] 34x7 + FC (fiber core)

[0060] 34x7 + IWS (“Independent wire strand core”)

[0061] 36x7 + FC

[0062] 36x7 +IWS

[0063] The individual metal wires of these ropes can have diameters between 0.05 mm and 0.1 mm. Alternatively, the pintle wire can have a polymer core around which metallic threads or strands are arranged.

[0064] Alternatively, the pintle wire can have a metallic core (a wire, a braid, a thread, especially a rope), with this core surrounded by a sheath made of polymer material. Ideally, the polymer material is a good thermal conductor. The polymer sheath protects the metallic core, prevents kinks, and facilitates the insertion and removal of the pintle wire.

[0065] Graphene, certain carbon filaments, or sputtered / plated yarns are possible, depending on the required resistance. Sputtered or plated polymer yarns have a metallic coating, and the typical size of such yarns is often very small (e.g., 0.1 mm), as the coating process is inefficient for larger-diameter yarns with good electrical properties. Therefore, a combination of sputtered / plated yarns is required to achieve the required pintle diameters. The integrity of the pintle requires that the combination of small coated yarns act as a single unit. Therefore, a pintle with coated polymer yarns can consist of a braid, a rope, a mesh of braids, a cable, etc.

[0066] An improvement to the conductive braid can be a solid polymer core, which can also be coated or left uncoated. The solid polymer core can serve as a tensile load carrier, but can also increase the stiffness of the outer braids or braids and reduce the overall cost of the patch cord.

[0067] Polymers for use in pintle wires can be polyamides, PET, PEEK and other materials within the specified temperature specifications.

[0068] The use of polymer yarn systems as pintle wire has a surprising advantage for the heat-setting process. During the heat cycle, and depending on the temperature, the polymer yarn shrinks in length and increases slightly in diameter. Increasing the diameter can contribute to round, uniform seam loop formation. Ideally, the diameter increases during the heat cycle and returns to its original diameter after cooling.

[0069] The process of thermally fixing loops using a conductive pintle wire can advantageously be controlled. The control can be either temperature-controlled via thermocouples or current-controlled. Thermocouples are used as a feedback loop for the control to regulate the current in the circuit. The time-controlled heat setting can also be automated.

[0070] Thermocouples can be omitted if the resistivity of the pins is known. The resistance of most conductive materials is quite stable within the specified temperature range (room temperature - 190°C).

[0071] The following example is intended to illustrate the invention in more detail. However, the invention is not limited to this example.

[0072] • Base fabric: Flat fabric in plain weave with longitudinal and transverse threads made of PA6

[0073] • Diameter of MD threads 0.4 mm

[0074] • Diameter of the electrically conductive plug wire: 1.4mm

[0075] • The pin wire is made of Konstanten ® yarn.

[0076] • The voltage was increased until the temperature of the plug wire reached 150°C.

[0077] • Duration of thermal treatment: 2 minutes to 10 minutes, e.g. 5 minutes.

[0078] • The voltage is then slowly reduced to zero (e.g. over 60 seconds)

[0079] So far, the thermal setting processes for fabrics have been described in which the seam loops are created by folding a flat weave. In the traditional production of seamed fabrics, the seam loops are created directly on the loom. For this purpose, weaving pintles are drawn in the MD direction on both sides of the loom. The CD threads are then woven around these weaving wires. After removing the weaving wires, the seam loops are created, which can be interlaced in a similar way to the process described above. Such seam loops can also be thermally set using an electrically conductive pintle wire.

[0080] In particular, it is also possible for the weaving pintle to be designed as an electrically conductive pintle wire according to one of the aspects described above.

[0081] The processes described above can be used for a wide variety of applications. For example, they can be used to produce base fabrics for paper machine clothing, e.g., seamed felts, as well as for other fabric belts with pin-wire seams, such as conveyor belts, functional belts, etc.

[0082] The invention is explained in more detail below with reference to the figures. The invention is not limited to the variants shown in the figures. The figures show in detail:

[0083] Figures 1 a to 1 d illustrate steps of a method according to one aspect of the invention

[0084] Figures 2a to 2d 1d illustrate steps of a method according to a further aspect of the invention

[0085] Figures 3 and 4 show suture loops with pintle wires for carrying out method steps according to various aspects of the invention.

[0086] Figures 1a to 1d illustrate steps of a method according to one aspect of the invention. First, a flat fabric 3 is provided, woven from longitudinal threads 4 and transverse threads 5. In contrast to circular fabrics, such flat fabrics 3 can be produced very quickly. After weaving, the flat fabric 3 is subjected to a thermal setting process ("heat setting"). This removes the tensions in the fabric threads 4, 5, but also deforms these fabric threads 4, 5.

[0087] For methods according to various aspects of the present invention, plain weave fabrics can be used as the flat fabric 3. It is also conceivable for one or more parameters of the weave pattern to change at a certain point on the flat fabric 3. Such a change is expediently provided at the future folding point.

[0088] In Figure 1 b, some transverse threads 5 have been removed in the area surrounding this fold. Typically, 3 to 7 transverse threads 5 are removed. By removing the transverse threads 5, a so-called window 6 is formed in the flat fabric 3, in which the flat fabric 3 only has longitudinal threads 4. After such a window 6 has been prepared, the flat fabric 3 can be folded and formed into a two-layer structure by laying it on itself. This is shown in Figure 1 c. This creates a seam loop 2 at the fold. By removing the transverse threads 5 and forming a window 6, the seam loop 2 is essentially formed by longitudinal threads 4. This facilitates the insertion of a pintle wire 1.

[0089] However, the longitudinal threads 4 are still deformed by the thermal setting process. Round, level seam loops are the basis for good seam coverings. These deformations should be removed by further thermal treatment – ​​possibly in combination with a certain amount of tension in the longitudinal direction.

[0090] In a method according to one aspect of the invention, as shown in Figure 1d, an electrically conductive pintle wire 1 is inserted into the seam loop 2. 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. This acts as a resistor and heats up. The heated pintle wire 1 heats the longitudinal threads 4 of the seam loop 2. This allows the deformations in the longitudinal wires 4 to be released. 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 adjusted based on the determined temperature values. This can be done manually or in the form of an automated control loop.In this process, the energy is applied specifically only in the area of ​​the seam loops 2. This allows energy savings compared to the conventional process. On the other hand, the process described in Figures 1a to 1d also makes it possible to thermally fix the seam loops of the loop elements described in EP4010528, which are only present as a short loop element with a seam loop 2 and cannot be joined to form a closed endless belt.

[0091] While the method described in Figures 1a to 1d is suitable for thermally setting a single seam loop, Figures 2a to 2d show an alternative embodiment of the method in which two seam loops 2 can be thermally set simultaneously, similar to the conventional process. In Figure 2a, as in Figure 1a, a flat woven fabric 3 is again provided, comprising longitudinal threads 4 and transverse threads 5, wherein the flat woven fabric 3 has in particular undergone a first thermal setting process. The flat woven fabric 3 has in particular twice the length of the later basic structure. As shown in Figure 2b, windows 6 are now formed at two locations by removing transverse threads 5. These windows 6 have a distance in the longitudinal direction of the flat woven fabric 3 that corresponds to the length of the later basic structure.By folding the flat fabric 3 at two fold points in the area of ​​the two windows 6, a two-layer structure is created, forming two seam loops 2 at the respective fold points. The existing front edges of the flat fabric 3 are usually joined, in particular welded. As shown in Figure 2c, the two seam loops 3 can be guided into one another and connected using a pintle wire. This creates a closed, two-layer endless belt.

[0092] As shown in Figure 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 that the electrically conductive pintle wire 1 is heated by applying an electrical voltage source 11 to thermally fix the two night loops 2. As can be seen in Figure 2d, both seam loops 2 are connected to the electrically conductive pintle wire 1 and are simultaneously thermally fixed by heating the electrically conductive pintle wire 1. A temperature sensor can also be provided here, and the voltage 11 can be regulated based on the measured temperatures.

[0093] Thermally fixing the seam loops 2 in the form of a closed, endless band can be advantageous, as it allows, for example, a desired pre-tension to be applied to the seam loops very easily. This allows the shape of the seam loops 2 to be influenced within certain limits.

[0094] There are various options available for designing the electrically conductive pintle wire 1. In principle, it is possible to design it as a simple metallic monowire 1, in particular with a circular cross-section. However, this has the disadvantage that with electrical conductors, the resistance decreases with increasing wire diameter, as a result of which the wire heats up less. This is often disadvantageous, particularly with seam loops 2 with a larger loop diameter. Figure 3 shows, as a possible alternative, an electrically conductive pintle wire 1 designed as a twisted yarn 7. In Figure 3, the twisted yarn 7 consists, by way of example, of four yarns 8, all four yarns 8 being designed as electrically conductive yarns 8. The yarns shown here are plastic filaments coated with a conductive layer, in particular a metallic layer.This has the advantage that the thread 7 as such is electrically conductive, but the resistance of the thread 7 is only slightly reduced even with larger diameters, since the individual conductive threads 8 have an electrically non-conductive plastic core.

[0095] Another possible embodiment of the electrically conductive pin wire 1 is shown in Figure 4. Here, the electrically conductive pin wire 1 is again designed as a twisted yarn 7 made of four individual yarns. However, the twisted yarn 7 here consists of a combination of conductive yarns 8 and non-electrically conductive yarns 9. In the example in Figure 4, these are two conductive yarns 7 and two non-conductive yarns 9. In general, however, other ratios and also other numbers of yarns 8, 9 in the twisted yarn 7 are also possible. This can also prevent the

[0096] The resistance of the electrically conductive pintle wire 1 drops too sharply with increasing diameter. The metallically coated plastic filaments shown in Figure 3 can again be used as electrically conductive pintles. Alternatively or additionally, other conductive pintles, such as metallic monowires, can also be used.

[0097] List of reference symbols

[0098] 1 electrically conductive plug wire

[0099] 2 seam loop 3 flat weave

[0100] 4 longitudinal threads

[0101] 5 cross threads

[0102] 6 windows

[0103] 7 thread 8 electrically conductive yarn

[0104] 9 non-electrically conductive yarn

[0105] 11 Voltage source

Claims

Patent claims 1 . Method for the thermal fixing of a seam loop (2) for a basic structure for a clothing, in particular for a seam felt of a paper machine, comprising the steps of a. providing a flat woven fabric (3) comprising longitudinal threads (4) and transverse threads (5), wherein the flat woven fabric (3) has in particular undergone a first thermal fixing process, b. folding the flat woven fabric (3) into a two-layer structure at at least one folding point to form a seam loop (2) at the respective folding point, c. inserting a pintle wire (1) into the seam loop (2), characterized in that d. the pintle wire (1) is designed as an electrically conductive pintle wire (1), and the electrically conductive pintle wire (1) is heated by applying an electrical voltage (11) to thermally fix the seam loop (2).

2. Method according to claim 1, characterized in that steps b. and c. are carried out as follows: d. Folding the flat fabric (1) into a two-layer structure at two folding points, forming two seam loops (2) at the respective folding points, and joining the two end edges of the flat fabric (3) to one another. e. Bringing the two seam loops (2) into one another and joining them by inserting a pintle wire (1) to form a two-layer fabric loop, wherein both seam loops (2) are thermally fixed simultaneously. Method according to one of the preceding claims, characterized in that the method further comprises step a2. Removing a plurality of adjacent transverse threads (5) in the region of the folds, wherein step a2 is carried out in particular between steps a. and b. Method according to one of the preceding claims, characterized in that the electrically conductive pintle wire (1) is a monowire which in particular has a circular cross-section. Method according to one of claims 1 to 3, characterized in that the electrically conductive pintle wire (1) is designed as a twisted yarn (7) or as a braided structure made up of a plurality of yarns (8, 9). Method according to claim 5, characterized in that the twisted yarn (7) or the braided structure is formed exclusively from electrically conductive yarns (8), or that the twisted yarn (7) orthe braided structure consists of a combination of electrically conductive yarns (8) and non-electrically conductive yarns (9). Method according to one of the preceding claims, characterized in that the electrically conductive pintle wire (1) is designed as a metallic pintle wire (1). Method according to one of claims 1 to 6, characterized in that the electrically conductive pintle wire (1) comprises or consists of a polymer wire which is made conductive by introducing particles or by coating. Method according to one of the preceding claims, characterized in that at least one sensor for determining the temperature of the electrically conductive pintle wire and / or the. Seam loops (2) are provided, wherein determined temperature values ​​are used in particular for regulating the electrical voltage (11). Basic structure for a clothing, in particular for a seam felt of a paper machine, which is produced by a method according to one of the preceding Claims. A fabric, in particular seam felt for a paper machine, comprising at least one basic structure according to claim 10.

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