EP2898144B1 - Paper machine wire - Google Patents

Description

The present invention relates to a multi-ply papermaking fabric, e.g. a sheet forming screen of a paper machine, in particular a forming screen as used in the process of papermaking in the sheet forming zone of a wet end of a paper machine for dewatering / filtration of a pulp suspension or a paper pulp. Such screens are mainly used for high-quality graphic papers and packaging papers with low paper weight / surface area and high demands on the printability. These papers can be produced with so-called gap formers or gap formers at speeds of more than 2000 m / min. High demands are placed on the mechanical stability, the drainage performance, the fiber support, the freedom from marking and the running time of the sieve.

An essential process within papermaking is the formation of the sheet (= sheet formation) which takes place by dewatering a pulp suspension or a paper pulp by means of filtration in the sheet forming zone of the wet end of a paper machine using a so-called sheet forming screen.

Fibrous suspension is understood to mean a mixture of wood or cellulose fibers, fillers and chemical auxiliaries suspended in water.

In order to be able to produce a sheet of paper that is as uniform as possible, it is necessary to increase or adjust the water content of the pulp suspension to approximately 99% immediately before sheet formation. This ensures that the fibers can be distributed evenly in the water, which has an advantageous effect on the quality of the sheet to be formed.

Within the foliation zone, i. during the sheet forming process, the water content is reduced to about 80% by the above-mentioned filtration process. The paper fibers and the fillers and auxiliaries remain evenly distributed in the form of a non-woven fabric on the papermachine fabric.

While in the past drainage was mainly by a paper machine screen applied to a fourdrinier machine, today twin-wire machines are predominantly used, e.g. in the form of a so-called gap former (in English "Gap-Former"). These twin-wire machines are characterized in that the pulp suspension is injected into a gap formed between two paper machine wires, so that the dewatering can take place simultaneously through both wires, whereby the filtration process and thus also the production speed of the paper machine can be significantly accelerated. Today paper machines are available for paper grades with low basis weights that can produce at speeds of more than 2000 m / min.

The extreme demands placed on the paper to be produced and the conditions prevailing in the paper machine require specially designed sheet forming screens which at the same time have high fiber support, high openness and high mechanical stability. In addition, for the area of graphic papers, a slight tendency to marrow of the tissue is additionally required.

In recent years, multilayer paper machine screens have been proven for such applications, the two have different trained sides, which are adapted to the particular purpose. Such screens have a paper side formed by the top of an upper fabric. The paper page is commonly referred to as Sieboberseite and is responsible for the formation of the paper sheet. In addition, these sieves have a running side, which is formed by the underside of a lower fabric. The running side, which can also be referred to as the underside of the screen, comes into contact with the elements of the paper machine. The respective screen side has a machine direction (usually longitudinal direction) and a transverse direction, wherein the machine direction (in English MD for "machine direction") is understood to mean the direction of travel of the paper web and thus also the running direction of the paper machine screen, and wherein the transverse direction (in English CMD for "cross machine direction"), sometimes also referred to as cross-machine direction, which is in the plane of the papermachine fabric rotated by 90 °, ie, the direction transverse to the direction of the paper and the screen direction.

Due to the very special structure of modern paper machine screens can usually exchange neither paper and running side, nor longitudinal / machine and transverse direction, otherwise the functioning of the screen is not or not sufficiently guaranteed. For example, on the running side, the machine direction threads (= longitudinal threads), which realize the circulation of the screen, are protected against wear by clearly protruding or protruding transverse threads. On the paper side, for example, by providing a balanced ratio of longitudinal and transverse threads, a good storage option for the paper fibers can be ensured. Regarding the fiber support but also with respect to the tendency of the sieve to mark the upper tissue and Thus, for the paper side, the simplest and at the same time oldest basic weave of textile technology, the so-called plain weave, has proven itself. In this binding, whose weave repeat (= smallest repeat unit of weave) consists of exactly two warp threads (usually the warp threads form the longitudinal threads / machine direction threads of the wire) and two weft threads (usually the weft threads of the wire become the warp threads formed), the threads are connected in a particularly intimate and uniform manner to a tissue. As suitable the plain weave is for the formation of a paper sheet and thus for the paper side, so little is it usually suitable for the running side. If a paper machine screen is provided with a canvas paper side, it may therefore be advisable to provide a second fabric layer below the plain weave which forms the running side of the screen, which gives the screen sufficient stability and wear potential.

A particular challenge in this context is the connection of the two layers (i.e., the top side forming the paper side with the bottom side forming the running side), i.a. This is because the plain weave, which is favorable for the paper side, has extremely unfavorable requirements for such a layered connection.

In the prior art, different approaches are described for the connection of two fabric layers of mesh, one approach of which provides for the use of additional (not belonging to the structure or the binding pattern / matching), separate binding threads, which extend in the longitudinal and / or transverse direction , According to this approach, two finished, fully formed fabric layers are connected to each other via separate / additional binding threads, which binder threads do not contribute to the construction of the respective fabric layer binding become. The two fabric layers consist of longitudinal threads and transverse threads, which extend exclusively in the respective fabric layer and thereby completely generate the respective fabric layer pattern or the respective fabric layer weave. This procedure is described eg in CA 1 115 177 A1 where separate binding wefts are used which bind with warp threads of the upper fabric and warp threads of the lower fabric, and DE 39 28 484 A1 , in which separate warp threads are used as connecting threads. Further examples are in DE 42 29 828 A1 . WO 93/00472 and EP 0 136 284 A2 to find. The separate binding threads are usually made thinner than the respective fabric layer forming threads (see, eg CA 1 115 177 A1 ), since the binding threads must be added to the fabric structure in addition to the fabric-forming threads, with little space for such separate binding threads, especially in a plain weave. Otherwise, the originally homogeneous structure of the binding would be disturbed by the binding threads, so that in particular in the provided on the paper side plain weave defects would be created that cause marks in the paper. In practice, however, it has been shown that the thin binding threads, especially in paper machines that process a high proportion of abrasive fillers or whose construction loads the screens strongly on bending in the machine direction, wear and break quite quickly, so that subsequently the two fabric layers first move and later separate. Of course, it is no longer possible to produce high-quality paper with such a changed fabric / sieve.

An alternative to this is the use of structural threads (belonging to / contributing to the structure or weave pattern of at least one fabric layer) for joining the layers. The threads used for the layer connection ("binding threads") serve on the one hand to connect the layers, for which they switch back and forth between the layers, and on the other hand form the upper fabric and / or the lower fabric (esp. The respective recurrent characteristic binding or overlapping pattern) , Various structural threads may be used as connecting threads, eg, transverse threads (or alternatively longitudinal threads) which structurally form the topsheet, with the different structural threads having different screening properties.

Furthermore, it is known to use two transverse threads arranged adjacently in the longitudinal direction, which interact as a so-called functional transverse thread pair. The two transverse threads of a functional pair form alternately on the paper side together a virtually uninterrupted transverse thread, which fits into the binding pattern of the paper side and may be part of a paper-side plain weave, for example. Those portions of the thread of the functional pair that are not currently required for the formation of the paper-side virtually uninterrupted transverse thread run inside the fabric and can be used to attach the lower fabric to the upper fabric. At the same time, the thread section tying the lower fabric can, for example, at the same time complete the lower fabric or its binding. For example, one or both transverse threads of a functional pair can alternately run in the upper and lower tissues. For example, an upper transverse thread can be arranged between two functional transverse thread pairs, which exclusively completes the plain weave (ie which runs only in the upper fabric), but has no binding function. Exemplary embodiments of this approach can be found for example in EP 0 097 966 A2 . EP 794 283 A1 . WO 99/06630 A1 . WO 99/06632 A1 and WO 02/14601 A1 , Alternatively, the connection of the layers can be effected by so-called functional longitudinal thread pairs. For example, be on EP 0 069 101 and EP 093 096 referenced, which show a layer connection via functional longitudinal thread pairs.

• EP 1 021 616 B1 von Kevin J. Ward zeigt ein Gewebe, bei dem die Papierseite in Querrichtung ausschließlich von funktionalen Querfadenpaaren gebildet ist, d.h., es sind keine reinen oberen Querfäden vorhanden (siehe Figur 1a des genannten Patents). Die Papierseite eines derartigen Siebs hat eine vergleichsweise starke Markierneigung, da eine Stützung der oberen Längsfäden bzw. eine Stabilisierung des Obergewebes durch reine obere Querfäden entfällt. Die mit einer Leinwandbindung realisierte Papierseite wird aufgrund der fehlenden oberen Querfäden und der großen Anzahl an Wechselstellen ungleichmäßig. Zudem ist die eingesetzte Menge an Querfäden groß.

Concerning. The tissue connected via functional transverse thread pairs can also be referred to the following patent literature:

• EP 1 021 616 B1 by Kevin J. Ward shows a fabric in which the paper side is formed in the transverse direction exclusively by functional transverse thread pairs, ie there are no pure upper transverse threads (see FIG. 1a of the cited patent). The paper side of such a sieve has a relatively strong Markierneigung, since a support of the upper longitudinal threads or a stabilization of the upper fabric deleted by pure upper transverse threads. The paper side realized with a plain weave becomes uneven due to the missing upper cross threads and the large number of change points. In addition, the amount of transverse threads used is large.

In the patent EP 1 311 723 B1 Heinz Odenthal shows a fabric in which the paper side is formed in the transverse direction exclusively by functional transverse thread pairs, wherein only one pair of the two transverse threads is formed as a binding thread which dips into the lower fabric layer (see FIG. 3 of the cited patent). In addition to an increased Markierneigung this tissue thus has a relatively small number of attachment sites (with a high number of introduced transverse threads).

EP 1 754 820 A1 by Johann Boeck shows a fabric in which on the paper side alternately two pure upper transverse threads and a functional transverse thread pair in the longitudinal direction one behind the other are arranged (see FIG. 1 the cited publication). Due to the comparatively small number of functional transverse thread pairs, the number of binding sites is relatively small.

Tissues in which an upper transverse thread and a functional transverse thread pair are alternately arranged longitudinally one after the other on the paper side are described, for example, in FIG EP 1 000 197 B1 to Kevin J. Ward . EP 1 158 089 B1 to Kevin J. Ward . EP 1 158 090 B1 to Kevin J. Ward . WO 2010/041123 A2 by Clara Rosetti . EP 0 794 283 B1 of Dale B. Johnson and others . US 5,826,627 to Ronald H. Seabrook . WO 2004/111333 A2 to Stewart L. Hay and WO 2005/014926 A1 to Stewart L. Hay , These tissues also have a relatively strong Markierneigung or an uneven paper side, since every other upper longitudinal thread is supported exclusively by functional transverse thread pairs, which form change points. In other words, all pure upper shots or upper transverse threads lie on the same warp threads or upper longitudinal threads (esp. On every other warp thread).

Further examples show constructions with a longitudinal thread or warp ratio of upper fabric to lower fabric not equal to 1 (a ratio of 1: 1 being particularly easy to implement). Such solutions are published in the patents EP 1 849 912 B1 Kevin J. Ward, in which a chain ratio of upper to lower fabric of 3 to 2 is described and in which also in the longitudinal direction on the paper side alternately a functional transverse thread pair and an upper transverse threads are arranged one behind the other, and US 7,487,805 B2 by Christine Baratte, Stewart Hay and Kevon J. Ward, in which a weft-bonded fabric with a warp ratio upper to lower warp smaller than 1 is described and in addition to the longitudinal direction on the paper side alternately functional transverse thread pair and two upper transverse threads are arranged one behind the other.

In the two patents EP 1 002 892 B1 from Ralf Kaldenhoff and EP 2 205 791 B1 Petra Hack-Ueberall and Arved Westerkamp propose the simultaneous use of pairs of warp yarns and weft yarn pairs as a solution for a stable ply joint.

A papermaker's fabric according to the preamble of claim 1 is known from WO 2004/111333 A2 known.

The present invention now describes a papermaker's fabric which is to be counted among that group of fabrics whose plies are connected by functional transverse thread pairs. Within this group, the sieve according to the invention can be counted among those subgroups in which the two transverse threads of a respective functional pair complete the upper binding alternately (thus providing a structural, virtually uninterrupted transverse thread for the upper fabric layer) and only the lower binding or layer tie to the top layer, so do not contribute to the formation of the lower bond pattern. Furthermore, the sieve according to the invention can be included in that subgroup in which both transverse threads of a respective transverse thread pair are designed as binding transverse threads, so that a high number of connections can be achieved.

The object of the present invention is to provide a sheet forming screen of a multi-layered fabric, which meets the requirements described above at least partially, esp. Completely (ie, for example, a high fiber support, a low Markierneigung, functional mechanical stability and has a stable layer connection or together) and which is also easy to implement.

To achieve this object, the invention provides a papermaking fabric according to claim 1. Further embodiments of the sieve according to the invention are described in the dependent claims.

The papermaker's fabric of the present invention, particularly a forming fabric, is formed as a cross-linked, multi-ply (e.g., two-ply) fabric having an upper fabric layer having a first weave and a lower fabric layer having a second weave. The multi-ply fabric has an overall repeat (e.g., consists of the repeating overall repeat) containing the following threads (e.g., consisting of the following threads). Upper longitudinal threads, which extend exclusively in the upper fabric layer, lower longitudinal threads, which extend exclusively in the lower fabric layer, upper transverse threads, which extend exclusively in the upper fabric layer and are interwoven with the upper longitudinal threads with partial formation of the first binding, lower transverse threads, which run exclusively in the lower fabric layer and are interwoven with the lower longitudinal threads with complete formation of the second binding, and binding transverse threads which extend both in the upper fabric layer and in the lower fabric layer and thereby connect the lower fabric layer to the upper fabric layer.

The ratio of the upper longitudinal threads to the lower longitudinal threads is 1: 1, the lower longitudinal threads have a diameter greater than or equal to the diameter of the upper longitudinal threads, and the lower transverse threads have a diameter which is greater than the diameter of the upper transverse threads.

The binding transverse threads form within the Gesamtrapports functional Querfadenpaare from two directly juxtaposed binding transverse threads, the two binding transverse threads of a respective functional transverse thread pair with common formation of an imaginary (uninterrupted) upper transverse thread (which fits into the binding pattern of the top and esp. assumes the characteristic of the binding typical course of an upper transverse thread (with respect to the upper longitudinal threads)) in alternation complete the first binding and thereby overflow one or more upper longitudinal threads, and wherein the two binding transverse threads of each / each functional transverse thread pair alternately the lower Tie the fabric layer with the second binding completely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair during its course i n the lower fabric layer within the Gesamtrapports at least one lower longitudinal thread underflows.

In the overall repeat, the functional transverse thread pairs in the upper fabric layer are arranged longitudinally in groups of two or more (eg exactly two) immediately adjacent functional transverse thread pairs (especially without an upper transverse thread therebetween), two consecutive groups passing through each one or two or more upper transverse threads are separated from each other.

A characteristic feature of the sieve according to the invention is the grouping (eg pairwise arrangement) of the functional transverse thread pairs on the sieve top side, the individual groups being formed by one or more pure upper transverse threads are separated from each other. In other words, two or more functional transverse thread pairs and one or more upper transverse threads are arranged alternately / alternately in the inventive wire on the paper side / upper side in the longitudinal direction. For example, in the inventive screen on the paper side / top in the longitudinal direction alternately (alternately) two functional transverse thread pairs and two upper transverse threads can be arranged one behind the other. Alternatively, in the inventive screen on the paper side / top in the longitudinal direction alternately / alternately, for example, (exactly) two functional transverse thread pairs and an upper transverse thread can be arranged one behind the other.

In other words, in contrast to the above-described transverse thread-bonded screens on the upper side instead of the alternating arrangement, "a functional transverse thread pair, an upper transverse thread" which arrangement leads to isolated / isolated functional transverse thread pairs, an arrangement is used in which the functional transverse thread pairs are grouped at least in pairs Thus, at least two immediately successive functional transverse thread pairs are present in the longitudinal direction (without an upper transverse thread in between).

With the sieve according to the invention, a stable layer connection can be achieved, with a suitable amount of transverse threads and an easy-to-implement longitudinal thread ratio as well as a low tendency Mark the paper side (due to a uniform formation of the same).

On the bottom of the sieve, the functional transverse thread pairs can also be grouped (eg arranged in pairs), with the individual groups being separated by one or more (eg exactly two) pure lower transverse threads are separated from each other. Alternatively or additionally, in the overall repeat all binding transverse threads of a respective group of functional transverse thread pairs in the lower fabric layer between the same two associated, in the longitudinal direction successive lower transverse threads connect the lower fabric layer to the upper fabric layer. Alternatively or additionally, in the lower fabric layer, the intermediate spaces formed between the lower transverse threads may be alternately occupied and unoccupied in the longitudinal direction, as shown, with connections by the binding transverse threads of a respective group of functional transverse thread pairs.

For example, the two binding transverse threads of a respective pair of transverse thread alternately connect the lower fabric layer to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair during its course in the lower fabric layer within the Gesamtrapports undergoes exactly one lower longitudinal thread.

For example, Within each group of functional transverse thread pairs, each binding transverse thread in the lower fabric layer may undercut (at least) another lower longitudinal thread.

For example, the first binding may be a plain weave (eg, an 8, 10, or 12-shaft plain weave) formed longitudinally from the upper longitudinal threads and transversely from the upper transverse threads and the imaginary upper transverse threads formed by the functional transverse thread pairs. A plain weave is as described above for the paper side particularly advantageous or has been proven for the paper side.

For example, For example, the total repeat and / or the repeat of the upper fabric layer may include 8, 10 or 12 upper longitudinal yarns.

For example, For example, the second weave may be a 5-shank weave or a 10-shank weave wherein the course of the respective lower transverse thread repeats transversely at 5 and 10 lower longitudinal strands, respectively. over a lower longitudinal thread and under four consecutive lower longitudinal threads or e.g. over two consecutive lower longitudinal threads and below eight consecutive lower longitudinal threads.

For example, In the overall repeat, each lower longitudinal thread can be bound in total by two binding transverse threads or four binding transverse threads. The respective longitudinal thread is thus securely involved.

For example, the overall repeat can include: 10 upper longitudinal threads, 10 lower longitudinal threads, 10 upper transverse threads, 10 lower transverse threads and 20 binding transverse threads, which form 10 functional transverse thread pairs.

Alternatively, the overall repeat may e.g. contain: 10 upper longitudinal threads, 10 lower longitudinal threads, 10 upper transverse threads, 20 lower transverse threads and 40 binding transverse threads, which form 20 functional transverse thread pairs.

For example, in the overall repeat, especially in the entire multi-ply fabric, all the longitudinal threads running in the upper fabric layer may be upper longitudinal threads extending exclusively in the upper fabric layer, and / or in the overall repeat, especially in the entire multi-ply fabric, all in the lower fabric layer extending longitudinal threads lower longitudinal threads be, which only in the lower Fabric layer run, and / or the upper fabric layer and the lower fabric layer in the Gesamtrapport, esp. In the entire multi-layer fabric, exclusively by the arranged to functional transverse thread pairs, binding transverse threads to be interconnected. For example, separate binding threads (not belonging to the structure or the binding pattern / fitting) can be completely dispensed with, as well as binding longitudinal threads.

For example, For example, the upper transverse threads may be made of polyester and the binding transverse threads of polyamide.

For example, For example, the binding transverse threads may have a diameter that is less than the diameter of the lower transverse threads. As a result, the paper side can be formed finer, and the binding transverse threads do not disturb the lower binding and can also be protected on the running side of the thicker lower transverse threads from wear. In particular, the binding transverse threads may have the same diameter as the upper transverse threads and / or the same diameter as the upper longitudinal threads, so that they fit well into the upper overlapping pattern. That is, e.g. For example, upper transverse threads, binding transverse threads and upper longitudinal threads can all have the same diameter.

For example, the total repeat in the upper fabric layer, e.g. also in the lower tissue layer, a total of five groups or ten groups of functional pairs.

For example, the longitudinal threads are formed as warp threads and the transverse threads as weft threads.

For example, in the overall repeat, the ratio of upper transverse threads, including functional transverse thread pairs, may increase lower transverse threads are greater than 1, in particular 2: 1, for example 20:10, or 3: 2, for example 30:20. With a longitudinal thread ratio of 1: 1 and a smaller thread diameter for the upper transverse threads, the inventive screen on the paper side can thus have a high fineness to ensure proper fiber support. The running side may have an increased openness to the paper side for good drainage behavior and a reduced tendency for the fabric to become clogged with fibers and contaminants. The running side in particular has a high mechanical stability against elongation. The internal wear and ultimately a ply separation can be avoided or greatly reduced in the multilayer sheet forming screen whose fabric layers are interconnected by upper transverse threads.

For example, In the overall repeat, the ratio of upper transverse threads to functional transverse thread pairs can be 1: 1 or 1: 2, which ratios ensure a suitable number of connection points, in the latter case the number of connection points being increased.

Therefore, according to the invention, a fine fabric having a very homogeneous design can be used for sheet formation and tied to a stable and coarser lower fabric. The upper fabric is preferably realized with a plain weave and thus ideally suited for the production of graphic paper. In particular, the lower tissue is coarser in the longitudinal direction and can offer the following advantages, for example: any solids that have penetrated into the tissue through the upper tissue are not retained in the lower tissue; the drainage performance of the screen is determined solely by the paper side; the lower tissue is so open that its influence is subordinate to the total flow. The rough one Lower fabric is used in particular to optimize the total screen in terms of mechanical stability and wear resistance and fabric thickness.

For example, In the overall repeat, each functional transverse thread pair can form exactly two intersection points at which the two binding transverse threads belonging to the pair intersect (in particular below an upper longitudinal thread) and change into the respective other fabric layer. Alternatively or additionally, the intersections of all the functional transverse thread pairs within the overall repeat can be evenly distributed on the upper longitudinal threads so that the same number of intersections are positioned under each upper longitudinal thread or along each upper longitudinal thread, e.g. exactly two or exactly four. As a result, a uniform paper page can be provided.

Further variations of the inventive sieve will become apparent from the following description of exemplary embodiments.

• Als Längsfäden werden Fäden des Siebes/Gewebes bezeichnet, die in Längsrichtung bzw. Längserstreckung des Siebs verlaufen und im Betrieb in Laufrichtung der Papiermaschine angeordnet sind. Beim flach gewebten Sieb sind die Längsfäden durch die Kettfäden des Webstuhls gebildet. Rundgewebe hingegen realisieren die Längsfäden mit den Schüssen.

Here are some terms used in this application:

• As longitudinal yarns threads of the screen / fabric are referred to, which extend in the longitudinal direction or longitudinal extent of the screen and are arranged in operation in the running direction of the paper machine. In the flat woven screen, the longitudinal threads are formed by the warp threads of the loom. Round fabrics, on the other hand, realize the longitudinal threads with the wefts.

As transverse threads, threads of the screen / fabric are referred to, which extend in the transverse direction of the screen and are arranged transversely to the running direction of the paper machine during operation. When flat woven sieve, the transverse threads are formed by the shots. Round fabrics, on the other hand, realize the transverse threads with the chains of the loom.

As a fabric layer is usually a single-layer fabric understood, comprising or consisting of interwoven transverse threads and longitudinal thread (or chains and shots).

The upper fabric or the upper fabric layer is a usually very finely formed fabric layer, from the i.d.R. the paper side (= outwardly facing, upper side of the upper fabric) of the screen on which the paper fiber layer is formed is formed. The upper fabric is on the "logical top" of the screen.

The lower fabric or the lower fabric layer is an i.d.R. particularly robust trained fabric layer, from the i.d.R. the running side (= outwardly facing, lower side of the lower fabric) of the wire is formed, which comes into direct contact with the wear generating drive and dewatering elements of the paper machine.

Upper longitudinal threads are such threads that are exclusively in the upper fabric and are interwoven there with running in the upper fabric transverse threads. Upper longitudinal threads do not leave the upper fabric, i. they do not change into the lower tissue.

Upper transverse threads are such threads that are exclusively in the upper fabric and are interwoven there with the upper longitudinal threads. Upper transverse threads run exclusively in the upper tissue and do not change into the lower tissue.

According to the invention, upper transverse threads and upper longitudinal threads together partially form the first, upper binding which Bonding by the binding transverse threads or functional pairs (see below) is completed. That is to say figuratively, gaps are created in the upper fabric by eliminating a predetermined number of upper transverse threads, which are closed again by the functional pairs. Advantageously, the first, upper binding is a plain weave.

Lower longitudinal threads are those threads that are located exclusively in the lower fabric and are interwoven there with running in the lower fabric transverse threads. Lower longitudinal threads do not leave the lower tissue, i. they do not change into the upper tissue.

Lower transverse threads are those threads that are exclusively in the lower fabric and are interwoven there with the lower longitudinal threads. Lower transverse threads do not leave the lower tissue, i. they do not change into the upper tissue.

According to the invention, lower transverse threads and lower longitudinal threads together completely form the second, lower binding.

Binding transverse threads are such transverse threads which run both in the upper fabric layer and in the lower fabric layer and thereby bind the lower fabric layer to the upper fabric layer.

A functional cross-thread pair is formed from two directly adjacent binding transverse threads (see also the comments made at the beginning on functional transverse thread pairs). According to the invention, the two transverse threads of a functional transverse thread pair together form an imaginary (uninterrupted) upper transverse thread at the top, which inserts itself into the binding pattern of the upper side, ie they complete the first binding and overflow in alternation in each case one or more upper longitudinal threads. Those portions of the thread of the functional pair that are not currently required for forming the paper-side virtually uninterrupted transverse thread may be used to attach the lower fabric to the upper fabric. According to the invention, both transverse threads of a respective functional transverse thread pair alternately bind the lower fabric layer to the upper fabric layer with the second binding completely formed by the lower longitudinal threads and the lower transverse threads by the respective transverse thread of a respective functional transverse thread pair during its course in the lower fabric layer within of the total repeat undergoes at least one (eg exactly one) lower longitudinal thread. That is, according to the invention, both transverse threads of a respective functional pair are formed as binding transverse threads.

The overall repeat of the fabric is a recurrent weave pattern / yarn overlay pattern of the entire fabric (including top and bottom fabrics), especially the smallest repeating unit of the entire fabric, with the progression of all yarns (upper and lower longitudinal yarns, upper and lower transverse yarns, binder Transverse threads) to one another, in particular the course of the respective thread in all / two layers. With knowledge of the total repeat, therefore, the complete fabric or sieve can be produced. That is, the sieve or the fabric may consist of a plurality of immediately arranged juxtaposed total repeats.

The weave repeat of the upper weave, or so-called upper weave repeat, is a recurrent pattern in the upper fabric of interwoven upper longitudinal threads, upper transverse threads, and binding transverse threads, especially the smallest repeating unit in the upper fabric. In plan view of the upper fabric or the paper side of the screen can be seen a variety of such upper binding repeats in the longitudinal and transverse direction of the screen. The upper weave repeat thus represents, in particular, the recurring overlapping pattern of the upper weave formed in the plan view of the upper fabric by the upper longitudinal threads, the upper transverse threads and the binding transverse threads (in particular also taking into account the change points of the functional pairs). In other words, the upper binding repeat relates to the course of the upper transverse threads and binding transverse threads with respect to the upper longitudinal threads and the resulting overlapping pattern; the course of the binding transverse threads with respect to the lower longitudinal threads has no meaning for the determination of the upper binding repeat. If one takes into account only the upper virtual / imaginary transverse thread formed by it (without taking account of the change point (s)) for the respective functional transverse thread pair, the so-called virtual / imaginary upper binding repeat is obtained, which can be realized in the form of a plain weave, for example.

The weave pattern of the lower fabric or the so-called lower weave repeat is a recurring pattern in the lower fabric of interwoven lower longitudinal and lower transverse threads, in particular the smallest repeating unit in the lower fabric. In plan view of the lower fabric or the running side of the screen, a plurality of such lower binding repeats in the longitudinal and transverse direction of the screen can be seen. The lower weave repeat therefore represents in particular the recurrent overlapping pattern of the lower weave formed in the plan view of the lower fabric by the lower longitudinal threads and the lower transverse threads (in particular without consideration of the binding sites by the functional pairs since these do not contribute to the binding). In other words, the lower bound repeat relates to the course of the lower transverse threads with respect to the lower longitudinal threads and the resulting overlapping pattern; the course of the binding transverse threads in the lower tissue has no significance for the lower binding repeat.

In the following the invention will be explained in more detail with reference to various embodiments with reference to the drawing.

BRIEF DESCRIPTION OF THE FIGURES

• FIG. 1 shows a section of a known sieve, esp. From its upper fabric layer, wherein the repeating on the paper side characteristic arrangement / subunit of two successive upper transverse threads and a functional cross-thread pair is shown, ie on the paper side are alternately two upper transverse threads and a functional transverse thread pair arranged longitudinally behind one another. Furthermore, it is indicated that it is a 10-shank bond, ie the transverse thread course (esp. The course of the binding transverse threads) is repeated after 10 upper longitudinal threads. The functional transverse thread pair forms an imaginary upper transverse thread, which forms a plain weave together with the two upper transverse threads and the upper longitudinal threads. The change points of the longitudinal sub-unit (not shown) may be transversely displaced. The characteristic subunit contains only a functional cross-thread pair.
• FIG. 2 shows a section of another known sieve, esp. From its upper fabric layer, wherein the repeating on the paper side in the longitudinal direction characteristic arrangement / subunit of an upper Cross thread and a functional cross-thread pair is shown, ie on the paper side, an upper transverse thread and a functional transverse thread pair are arranged alternately in the longitudinal direction one behind the other. Furthermore, it is indicated that it is a 10-shank bond, ie the transverse thread course (esp. The course of the binding transverse threads) is repeated after 10 upper longitudinal threads. The functional transverse thread pair forms an imaginary upper transverse thread, which forms a plain weave together with the upper transverse thread and the upper longitudinal thread. The change points of the longitudinal sub-unit (not shown) may be transversely displaced. The characteristic subunit contains only a functional cross-thread pair.
• FIG. 3 shows a section of a sieve according to the invention, esp. From its upper fabric layer, wherein on the paper side / top longitudinally repeating characteristic arrangement / subunit of two (immediately) successive upper transverse threads and two (immediately) successive functional transverse thread pairs is shown (the both upper transverse threads and the two functional transverse thread pairs are arranged in pairs), ie on the paper side, a pair of upper transverse threads and a pair of functional transverse thread pairs are arranged alternately in the longitudinal direction one behind the other. Furthermore, it is indicated that it is a 10-shank bond, ie the transverse thread course (esp. The course of the binding transverse threads) is repeated after 10 upper longitudinal threads.
• FIG. 4 shows a section of a sieve according to the invention, esp. From its upper fabric layer, wherein the repeating on the paper side / top longitudinally characteristic arrangement / subunit of two successive upper transverse threads and two successive functional transverse thread pairs are shown, ie, on the paper side, a pair of upper transverse threads and a pair of functional transverse thread pairs are arranged alternately in the longitudinal direction one behind the other. Furthermore, it is indicated that it is an 8-shank bond, ie the transverse thread course (esp. The course of the binding transverse threads) is repeated after 8 upper longitudinal threads.
• FIG. 5 shows a section of a sieve according to the invention, esp. From the upper fabric layer, wherein on the paper side / top longitudinally repeating characteristic arrangement / subunit of two successive upper transverse threads and two successive functional transverse thread pairs is shown, ie on the paper side are alternately a A pair of upper transverse threads and a pair of functional transverse thread pairs arranged one behind the other in the longitudinal direction. Furthermore, it is indicated that it is a 12-shank bond, ie the transverse thread course (esp. The course of the binding transverse threads) is repeated after 12 upper longitudinal threads.
• FIG. 6 shows a section of a sieve according to the invention, esp. From the upper fabric layer, wherein on the paper side / top repeating in the longitudinal direction characteristic arrangement / subunit of an upper transverse thread and two successive functional transverse thread pairs is shown, ie on the paper side are alternately an upper Cross thread and a pair of functional transverse thread pairs arranged longitudinally one behind the other. Furthermore, it is indicated that it is a 10-shank bond, ie the transverse thread course (esp. The course of the binding transverse threads) is repeated after 10 upper longitudinal threads.
  In the Figures 3-6 The functional transverse thread pairs each form an imaginary upper transverse thread which together with the upper transverse threads or the upper transverse thread and the upper longitudinal threads form a plain weave. The change points of the longitudinal sub-unit (not shown) may be transversely displaced. The respective characteristic subunit contains - unlike in the prior art according to the Figures 1 and 2 - Two longitudinally adjacent functional transverse thread pairs.
• The FIGS. 7a and 7b show the overall repeat of a paper machine screen, in particular sheet forming screen, serving multi-layer fabric according to a first embodiment of the invention, in particular the courses of all transverse threads of the overall repeat with respect to the lower and upper longitudinal threads.
• FIG. 8 shows a plan view of the upper fabric layer of the overall repeat. This corresponds at the same time to a plan view of the weave repeat of the upper fabric layer.
• FIG. 9 shows a plan view of the lower fabric layer of the overall repeat. This corresponds at the same time to a plan view of the weave repeat of the lower fabric layer.
• The FIGS. 10a to 10d show the total repeat of a paper machine screen, in particular sheet forming screen, serving multi-layer fabric according to a second embodiment of the invention, in particular the courses of all transverse threads of the overall repeat with respect to the lower and upper longitudinal threads.
• FIG. 11 shows a plan view of the upper fabric layer of the overall repeat. This corresponds at the same time to a plan view of the repeat of the upper fabric layer.
• FIG. 12 shows a plan view of the lower fabric layer of the overall repeat. This corresponds at the same time to a plan view of eight immediately adjacent binding repeats of the lower fabric layer.

DETAILED DESCRIPTION

In the following the invention will be explained in more detail with reference to two exemplary embodiments with reference to the drawing.

First, however, with reference to the FIGS. 1 to 6 a characteristic feature of the sieve / tissue according to the invention will be explained in more detail.

FIG. 1 shows a section of the upper fabric layer of a known screen, which illustrates the seen on the paper side in the longitudinal direction always repeating characteristic subunit of two successive upper transverse threads and a functional cross-thread pair (here for a 10-shaft plain weave, ie the transverse thread course is repeated according to FIG Longitudinal threads and the transverse threads form a plain weave with the longitudinal threads). That is, according to this known sieve, a pair of upper transverse threads and a functional transverse thread pair are alternately arranged on the paper side in the longitudinal direction.

FIG. 2 shows a section of the upper .Wegtebelage another known screen, which seen in the longitudinal direction on the paper side repetitive characteristic Subunit of an upper transverse thread and a functional cross-thread pair clarified (again for a 10-shaft plain weave). That is, according to this known sieve, an upper transverse thread and a functional transverse thread pair are alternately arranged on the paper side in the longitudinal direction.

The FIGS. 3 to 5 each show a section of a sieve according to the invention, esp. From its upper fabric layer, which illustrates the respective repeating on the paper side / top longitudinal characteristic subunit of two successive upper transverse threads and two successive functional transverse thread pairs. That is, according to these fabrics / wires according to the invention, a pair of upper transverse threads and a pair of functional transverse thread pairs are arranged one behind the other alternately on the paper side in the longitudinal direction. FIG. 3 shows this in the case of a 10-shank plain weave, FIG. 4 in the case of an 8-shank plain weave, and FIG. 5 in the case of a 12-shank plain weave.

FIG. 6 shows a section of a sieve according to the invention, esp. From its upper fabric layer, wherein on the paper side / top longitudinally repeating characteristic subunit of an upper transverse thread and two successive functional transverse thread pairs is shown (for example, a 10-shaft plain weave). That is, on the paper side, an upper transverse thread and a pair of functional transverse thread pairs are alternately arranged longitudinally in succession.

Unlike in the prior art after the Figures 1 and 2 where on the paper side functional transverse thread pairs are arranged longitudinally and by upper transverse threads are separated (or where the characteristic subunit contains only a functional cross-thread pair), the functional transverse thread pairs according to the invention on the paper side in groups separated by upper transverse threads, eg in pairs, arranged (or contains the characteristic subunit immediately adjacent functional transverse thread pairs).

The FIGS. 7a . 7b . 8th and 9 show the overall repeat of a multi-ply fabric serving as a papermaking fabric, in particular a forming fabric, according to a first embodiment of the invention, wherein the FIGS. 7a and 7b the courses of all transverse threads (upper, lower and binding transverse threads) of the Gesamtrapport respect. The lower and upper longitudinal threads show, FIG. 8 a plan view of the upper fabric layer (or top) of the Gesamtrapports shows, and wherein FIG. 9 a plan view of the lower fabric layer of the Gesamtrapports shows. The threads running from left to right in the figures are transverse threads (eg weft threads), and the threads running from bottom to top in the figures are longitudinal or machine direction threads (eg warp threads).

As seen in the figures, the multi-ply fabric has an upper fabric layer having a first weave (see FIG. 8 ; For example, the upper fabric layer forms the so-called. Paper side of the screen) and a lower, a second weave having fabric layer (see FIG. 9 ; For example, the lower fabric layer forms the so-called. Running side of the screen). These two fabric layers are connected or held together by (binding) transverse threads (see FIGS. 7a . 7b and 9 ), so that the fabric may be referred to as a cross-linked or cross-thread bonded fabric. For example, the upper fabric layer and the lower fabric layer in the Gesamtrapport, esp. In the entire multi-layer fabric, exclusively by the binding transverse threads arranged to form functional transverse thread pairs are connected to one another, ie they should be free of separate binding threads and / or binding longitudinal threads, for example.

The multi-ply fabric is formed of (eg, consists of, or formed exclusively of) a total repeat (repeating in the fabric) containing the following types of yarns: upper longitudinal yarns 1, 3, 5, 7, 9, etc., which are exclusively in the upper fabric layer run, lower longitudinal threads 2, 4, 6, 8, 10, etc., which run exclusively in the lower fabric layer, upper transverse threads 101, 102, 109, 110, 117, 118, 125, 126, etc., which exclusively in run the upper fabric layer and are interwoven with the upper longitudinal threads with partial formation of the first binding, lower transverse threads 103, 108, 111, 116, 119, 124, 127, etc., which extend exclusively in the lower fabric layer and with the lower longitudinal threads below are weaved complete training of the second binding, and binding transverse threads 104-107, 112-115, 120-123, etc. which respectively in the upper fabric layer as well as in the lower fabric layer run (ie, these threads change between hen the two fabric layers back and forth) and thereby tie the lower fabric layer to the upper fabric layer.

The ratio of the upper longitudinal threads 1, 3, 5, 7, 9, etc. to the lower longitudinal threads 2, 4, 6, 8, 10, etc. is 1: 1. As can be seen in the figures, the ratio of the upper longitudinal threads to the lower longitudinal threads in the overall repeat can be, for example, 10:10 (alternatively, for example, 12:12 or 8: 8). That is, the course of the binding threads of a respective transverse thread pair (with respect to the lower and upper longitudinal threads) may repeat in the transverse direction after 8, 10 or 12 upper longitudinal threads.

The lower longitudinal threads 2, 4, 6, 8, 10, etc. have a diameter which is greater than or equal to the diameter of the upper longitudinal threads 1, 3, 5, 7, 9, etc. As can be seen in the figures, upper and lower longitudinal threads may e.g. have the same diameter. The overall repeat and esp. The entire fabric can be formed in the longitudinal direction exclusively with upper and lower longitudinal threads. In other words, in the overall repeat, especially in the entire multi-ply fabric, all the longitudinal threads running in the upper fabric layer can be upper longitudinal threads which run exclusively in the upper fabric layer. Furthermore, in the overall repeat, especially in the entire multi-ply fabric, all the longitudinal threads running in the lower fabric layer may be lower longitudinal threads which run exclusively in the lower fabric layer.

As in the FIGS. 8 and 9 seen, the lower transverse threads 103, 108, 111, 116, 119, 124, 127, etc. have a diameter which is greater than the diameter of the upper transverse threads 101, 102, 109, 110, 117, 118, 125, 126th etc .. That is, the lower transverse threads are thicker than the upper transverse threads. The underside of the screen which comes into contact with the paper machine can be made robust by means of the thicker lower transverse threads, whereas the upper side of the screen which comes into contact with the fiber suspension can be formed finely by means of the thinner upper transverse threads. For example, the binding transverse threads 104-107, 112-115, 120-123 are also thinner than the lower transverse threads and, for example, have the same diameter as the upper transverse threads, so that the imaginary upper transverse thread formed by the respective functional pair is fine into the binding pattern of the upper binding. Since the lower longitudinal threads and the lower transverse threads do not change to the upper layer, the fine paper side is not disturbed by the robust lower threads. The comparatively thin, binding Cross threads, which change to the lower layer, disturb the lower binding only slightly. Furthermore, the comparatively thick lower transverse threads protrude further downward than the binding transverse threads during their stay in the lower layer, whereby the binding transverse threads are shielded from the lower transverse threads and protected from wear.

The ratio of the upper transverse threads to the lower transverse threads may be e.g. 1: 1, e.g. 10:10. Taking into account the functional transverse thread pairs or the imaginary upper transverse threads formed by them, the ratio (upper transverse threads + imaginary upper transverse threads) / lower transverse threads is e.g. 2: 1, especially 20:10. In other words, the paper side / top of the screen may be formed finer than the comparatively coarse running side / bottom of the screen. The functional transverse thread pairs are assigned to the upper fabric layer, since they contribute there to the formation of the first bond, whereas they serve in the lower fabric layer only for connection. The ratio of upper transverse threads to functional pairs may be e.g. 1: 1, e.g. 10:10. The upper transverse threads may e.g. of polyester and the binding transverse threads e.g. be made of polyamide.

As esp. In FIG. 8 The binding transverse threads within the overall repeat form so-called functional transverse thread pairs 104 + 105, 106 + 107, 112 + 113, etc., each consisting of two binding transverse threads arranged directly next to each other. The two binding transverse threads of a respective functional transverse thread pair complete the first binding alternately while forming an imaginary uninterrupted upper transverse thread, thereby overflowing in each case one or more upper longitudinal threads. As a result (due to the change) so-called alternating or intersection points, which occur in an associated longitudinal thread, arise in FIG. 8 marked with an "x" are and at which one thread of a pair at the top and the other thread of the pair on the bottom changes. As in FIG. 8 For example, each functional cross-thread pair can have / form exactly two change points per total repeat. The change points of all functional pairs can be distributed uniformly within the overall repeat, for example, on the upper longitudinal thread, eg accounts for two change points on each upper longitudinal thread. For example, the two change points of a respective pair with a slope of "3 longitudinal upper threads to the left" through the Gesamtrapport rise. The functional pair (not shown) of the next overall repeat (longitudinally above the repeat shown) following the functional pair 138 + 139 then has a course (including change points) identical to that of the functional pair 104 + 105. The two binding transverse threads of a respective functional pair of transverse threads alternately bind the lower fabric layer with the second binding completely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair during its course in the lower fabric layer Within the overall repeat at least one lower longitudinal thread underneath (eg exactly one lower longitudinal thread, as in FIG. 9 shown). In the overall repeat, the functional transverse thread pairs in the upper fabric layer in the longitudinal direction are arranged in groups AE of in each case two or more functional transverse thread pairs arranged directly behind one another (eg arranged in pairs, as in FIG FIG. 8 shown), wherein two successive groups AD are each separated by one or two or more upper transverse threads (eg by exactly two upper transverse threads, as in FIG. 8 shown).

Ie, as in FIG. 8 As shown in the overall repeat, the functional transverse thread pairs in the upper fabric layer can be arranged longitudinally eg in groups AE of exactly two functional transverse thread pairs arranged directly behind one another ("pairwise arrangement"), whereby two consecutive groups are separated from each other by precisely two upper transverse threads are. In other words, in the overall repeat on the upper side, a pair of upper transverse threads and a pair of functional transverse thread pairs are alternately arranged longitudinally in succession. For example, the total repeat can contain a total of five AE groups on the top.

As in FIG. 9 shown, the functional transverse thread pairs 104 + 105, 106 + 107, etc. in the overall repeat, for example, in the lower fabric layer seen in the longitudinal direction in groups A'-E 'of two or more immediately behind the other arranged functional transverse thread pairs arranged (eg, arranged in pairs , as in FIG. 9 shown), wherein between two successive groups of functional transverse thread pairs one or two or more lower transverse threads are arranged (eg exactly two lower transverse threads, as in FIG. 9 shown).

Ie, as in FIG. 9 In the overall repeat, the functional transverse thread pairs in the lower fabric layer can be arranged in the longitudinal direction, in particular, in groups of exactly two functional transverse thread pairs arranged immediately one behind the other ("pairwise arrangement"), two successive groups being separated from each other by exactly two lower transverse threads are. For example, the total repeat may contain a total of five groups A'-E 'on the bottom.

In other words, in the overall repeat all binding transverse threads of a respective group of functional transverse thread pairs in the lower fabric layer between the same two associated, in the longitudinal direction successive lower transverse threads connect the lower fabric layer to the upper fabric layer. For example, the transverse threads 104-107 bind between the two lower transverse threads 103 and 108, and the transverse threads 112-115 bind between the two lower transverse threads 111 and 116.

As in FIG. 9 As shown in the lower fabric layer, the interspaces formed between the lower transverse threads in the longitudinal direction can alternately be occupied and unoccupied with bonds by the binding transverse threads of a respective group of functional transverse thread pairs.

As in FIG. 9 Within each respective group of functional transverse thread pairs, each binding transverse thread in the lower fabric layer may undercut / tie another lower longitudinal thread.

As in FIG. 8 The first binding may advantageously be a plain weave formed longitudinally of the upper longitudinal threads and transversely of the upper transverse threads and the imaginary upper transverse threads formed by the functional transverse thread pairs. A plain weave is of particular advantage for the paper side and the sheet formation. However, other bindings for the paper side are also conceivable.

As in FIG. 9 can be seen, the second binding may be a 10-shaft bond, in which the course of the respective lower transverse thread 103, 108, 111, 116, etc. in the transverse direction to 10 lower longitudinal threads 2, 4, 6, 8, 10th , 12, etc. repeated. The course of the respective transverse thread is eg "over two successive lower longitudinal threads and then under eight consecutive lower longitudinal threads" (viewed from above, counting "over the edge", ie after the lower longitudinal thread 20 follows the lower longitudinal thread 2). As in FIG. 9 can see this cross thread course with a slope of "3 longitudinal threads to the left" from bottom to top through the Gesamtrapport or the repeat of the underside extend. The lower transverse thread (not shown) of the (above) adjacent rapport following the lower transverse thread 140 then again has a course identical to that of the lower transverse thread 103.

As in FIG. 9 As can be seen, in the overall repeat (and the repeat of the underside), each lower longitudinal thread of exactly two binding transverse threads can be undercut or incorporated. For example, the lower longitudinal thread 2 is bound by the transverse threads 114 and 136. As in FIG. 9 can be seen, the attachment points of a respective functional pair with a slope of "3 longitudinal threads to the left" by the overall repeat (and the repeat of the bottom) rise.

The fabric of the first embodiment belongs to the group of cross-linked fabrics described at the outset, in particular to the group of fabrics joined by functional transverse thread pairs which provide a virtually uninterrupted structural upper transverse thread at the top, and has a cross-thread bound Tissue in whose overall repeat no upper transverse threads are present on the upper side (but only functional transverse thread pairs), the advantage of a reduced Querfadenanzahl. Furthermore, the sieve or fabric of the first embodiment has no upper transverse threads with respect to a transverse thread-bonded fabric, in its overall repeat at the upper side There is the advantage of a reduced Markierneigung, since the upper transverse threads bring a tissue balance with it (eg, the fabric or the upper longitudinal threads are pressed by the upper transverse threads stronger upward than the functional transverse thread pairs forming change points). Furthermore, the sieve or fabric of the first embodiment also has the advantage of reduced tendency to march in relation to a transverse thread-bonded fabric in whose overall repeat at the top in the longitudinal direction alternately an upper transverse thread and a functional transverse thread pair, since every second upper longitudinal thread in the latter exclusively from functional pairs is supported. This can be broken / avoided by the paired arrangement of the functional pairs with two upper transverse threads disposed therebetween, in which case each upper longitudinal thread is supported (at least in sections) by upper transverse threads. Due to the ratio of upper transverse threads to functional pairs of 1: 1 on the upper side, a reliable connection of the lower side or a stable layer connection can also be ensured, ie sufficient binding points can be provided for the layer connection. In particular, on the paper side over the prior art after FIG. 1 An increase in the number of binding points to the layer connection per fiber support index (FSI Beran) can be achieved.

The FIGS. 10a-10d, 11 and 12 2 show the overall repeat of a multi-ply fabric serving as a papermaking fabric, in particular a forming fabric, according to a second embodiment of the invention, wherein FIG FIGS. 10a to 10d show the course of the respective transverse thread with respect to lower and upper longitudinal threads in the Gesamtrapport, where FIG. 11 shows a plan view of the upper fabric layer or top of the Gesamtrapports, and wherein FIG. 12 a plan view of the lower fabric layer of the Gesamtrapports shows. The in the figures from left to right-handed threads are transverse threads (eg weft threads), and in the figures from bottom to top extending threads are longitudinal or machine direction threads (eg warp threads).

As seen in the figures, analogous to the first embodiment, the multi-ply fabric has an upper fabric layer having a first weave (see FIG FIG. 11 ) and a lower, second-bonded fabric layer (see FIG. 12 ). These two fabric layers are connected or held together by binding transverse threads (see Figures 10a-10d ) so that the fabric can be referred to as a transverse thread-bonded fabric. For example, the upper fabric layer and the lower fabric layer in the overall repeat, in particular in the entire multi-layer fabric, can be connected to one another exclusively by the binding transverse threads arranged to form functional transverse thread pairs, ie, for example, be free of separate binding threads.

The multi-ply fabric is formed of (eg, exclusively formed from) a repeat (repeating in the fabric) containing the following types of yarns: upper longitudinal yarns 1, 3, 5, 7, 9, etc., which run exclusively in the upper fabric ply , lower longitudinal threads 2, 4, 6, 8, 10, etc., which run exclusively in the lower fabric layer, upper transverse threads 404, 411, 418, 425, etc., which extend exclusively in the upper fabric layer and with the upper longitudinal threads under partial Woven bottom training transverse threads 403, 405, 410, 412, 417, 419, etc., which run exclusively in the lower fabric layer and are interwoven with the lower longitudinal threads with complete formation of the second bond, and binding transverse threads 406- 409, 413-416, 420-423, 427-430 etc., which run both in the upper fabric layer as well as in the lower fabric layer (ie, these threads change between the two fabric layers back and forth) and thereby tie the lower fabric layer to the upper fabric layer.

The ratio of the upper longitudinal threads to the lower longitudinal threads is analogous to the first embodiment 1: 1. As can be seen in the figures, the ratio of the upper longitudinal threads to the lower longitudinal threads can in particular be e.g. Be 10:10.

The lower longitudinal threads have a diameter which is greater than or equal to the diameter of the upper longitudinal threads. As can be seen in the figures, upper and lower longitudinal threads may e.g. have the same diameter. The overall repeat, and in particular the entire tissue, may e.g. free of binding longitudinal threads, i. be formed in the longitudinal direction exclusively with upper and lower longitudinal threads. In other words, in the overall repeat, especially in the entire multi-ply fabric, all the longitudinal threads running in the upper fabric layer can be upper longitudinal threads which run exclusively in the upper fabric layer. Furthermore, in the overall repeat, especially in the entire multi-ply fabric, all the longitudinal threads running in the lower fabric layer may be lower longitudinal threads which run exclusively in the lower fabric layer.

As can be seen in the figures, analogous to the first embodiment, the lower transverse threads have a diameter which is greater than the diameter of the upper transverse threads. That is, the lower transverse threads are made thicker than the upper transverse threads. The binding transverse threads are e.g. also thinner than the lower transverse threads, and also have e.g. the same diameter as the upper transverse threads.

The ratio of the upper transverse threads to the lower transverse threads can be eg 1: 2, eg 10:20. Considering the functional transverse thread pairs or the imaginary upper transverse threads formed by these, the ratio (upper transverse threads + imaginary upper transverse threads) / lower transverse threads is 3: 2, in particular 30:20. The functional transverse thread pairs are assigned to the upper fabric layer, since they contribute there to the formation of the first bond, whereas they serve in the lower fabric layer only for connection. The top can thus be made finer than the relatively coarse bottom.

The ratio of upper transverse threads to functional pairs can be eg 1: 2, eg 10:20. This can be compared with the first embodiment as well as with respect to the prior art according to Figures 1 and 2 increase the number of connections. The upper transverse threads may be made of polyester, for example, and the binding transverse threads of polyamide, for example.

As esp. In FIG. 11 seen, analogous to the first embodiment, form the binding transverse threads within the Gesamtrapport so-called. Functional transverse thread pairs of two directly juxtaposed binding transverse threads. The two binding transverse threads of a respective functional transverse thread pair complete the first binding alternately while forming an imaginary, uninterrupted upper transverse thread and in each case overflow one or more upper longitudinal threads. As a result, below an associated longitudinal thread so-called. Change or intersection points, the FIG. 11 are partially marked with an "x" and where the one yarn of a pair on the top and the other thread of the pair changes to the bottom. As in FIG. 11 For example, each functional cross-thread pair can have / form exactly two change points per total repeat. The change points of all functional pairs can be within the overall repeat be evenly distributed on the upper longitudinal thread, for example, four change points can be omitted on each upper longitudinal thread. The functional pair (not shown) following the functional pair 469 + 470 of the next overall repeat (longitudinally above the repeat shown) has a course (including change points) identical to that of the functional pair 401 + 402. The two binding transverse threads of a respective functional pair of transverse threads alternately bind the lower fabric layer with the second binding completely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair during its course in the lower fabric layer Within the overall repeat at least one lower longitudinal thread underneath (eg exactly one lower longitudinal thread, as in FIG. 12 shown). In the overall repeat, the functional transverse thread pairs in the upper fabric layer in the longitudinal direction are arranged in groups AJ of two or more functional transverse thread pairs arranged directly behind one another (eg arranged in pairs, as in FIG FIG. 11 with respect to the pair J being counted across the edge), with two successive groups AJ being separated from each other by one or two or more top transverse threads (eg, by exactly one top transverse thread, as in FIG FIG. 11 shown).

Ie, as in FIG. 11 In the overall repeat, for example, the functional transverse thread pairs in the upper fabric layer can be arranged in groups AJ of exactly two functional transverse thread pairs arranged directly behind one another ("pairwise arrangement"), with two successive groups being separated from each other by exactly one upper transverse thread are. In other words, in the overall repeat on the upper side are alternating an upper transverse thread and a pair of functional transverse thread pairs are arranged one behind the other in the longitudinal direction. For example, the total repeat may contain a total of ten AJ groups on the top.

As in FIG. 12 shown, the functional transverse thread pairs in the overall repeat, for example, in the lower layer of fabric seen in the longitudinal direction in groups A'-J 'of two or more directly behind each other arranged functional transverse thread pairs arranged (eg arranged in pairs, as in FIG. 12 shown), wherein between two successive groups of functional transverse thread pairs one or two or more lower transverse threads are arranged (eg exactly two lower transverse threads, as in FIG. 12 shown).

For example, In the overall repeat, all binding transverse threads of a respective group of functional transverse thread pairs in the lower fabric layer between the same two associated, in the longitudinal direction successive lower transverse threads, the lower fabric layer to the upper fabric layer. For example, the transverse threads 406-409 bind between the two lower transverse threads 405 and 410, and the transverse threads 413-416 tie between the two lower transverse threads 412 and 417.

As in FIG. 12 As shown in the lower fabric layer, the interspaces formed between the lower transverse threads in the longitudinal direction can alternately be occupied and unoccupied with bonds by the binding transverse threads of a respective group of functional transverse thread pairs.

As in FIG. 12 Within each respective group of functional cross-thread pairs, each binding one may be shown as binding Cross thread in the lower fabric layer underneath another lower longitudinal thread.

As in FIG. 11 The first binding may advantageously be a plain weave formed longitudinally of the upper longitudinal threads and transversely of the upper transverse threads and the imaginary upper transverse threads formed by the functional transverse thread pairs. However, other bindings for the paper side are also conceivable.

As in FIG. 12 can be seen, the second binding may be a 5-shank bond, in which the course of the respective lower transverse thread 403, 405, 410, 412, etc. in the transverse direction after 5 lower longitudinal threads 2, 4, 6, 8, 10th , 12, etc. repeated. The course of the respective transverse thread is eg "over a lower longitudinal thread and then under four successive lower longitudinal threads" (viewed from above, counting "over the edge", ie after the lower longitudinal thread 20 is followed by the lower longitudinal thread 2). As in FIG. 12 can see this transverse thread course with a slope of "2 longitudinal threads to the right" from bottom to top through the Gesamtrapport or the repeat of the underside extend. The lower transverse thread 419 has the same course as the lower transverse thread 419 (and the lower transverse threads 438 and 454). In the transverse direction, the course of the transverse thread 403 is repeated from the sixth lower longitudinal thread from the left (= longitudinal thread 12). FIG. 12 thus shows a total of 8 lower binding repeats.

As in FIG. 12 In the overall repeat, each lower longitudinal thread can be undermined or bound by exactly four binding transverse threads. For example, the lower longitudinal thread 2 is bound by the transverse threads 408, 413, 444 and 449.

The fabric of the second embodiment, like the fabric of the first embodiment, belongs to the group of cross-linked fabrics described above, in particular to the group of fabrics joined by functional transverse thread pairs which provide a virtually continuous structural upper transverse thread at the top , and has the advantage of a reduced number of transverse threads compared to a cross-linked fabric, in whose Gesamtrapport at the top no upper transverse threads are present (but only functional transverse thread pairs). Further, the sieve or fabric of the second embodiment has the advantage of a reduced tendency to march over a cross-thread-bonded fabric, in whose Gesamtrapport at the top no upper transverse threads are present, since the upper transverse threads bring a tissue balance with it. Furthermore, the sieve or fabric of the second embodiment also has the advantage of reduced tendency to march over a transverse thread-bonded fabric in whose overall repeat on the upper side in the longitudinal direction an upper transverse thread and a functional transverse thread pair are alternately arranged, since in the latter every second upper longitudinal thread is exclusively composed of functional pairs is supported. This can be broken / avoided by the paired arrangement of the functional pairs with an upper transverse thread therebetween, in which case each upper longitudinal thread is supported (at least in part) by upper transverse threads. In addition, due to the ratio of upper transverse threads to functional pairs of 1: 2 on the upper side, a reliable connection of the lower side or a stable layer connection can be ensured, ie sufficient binding points can be provided for the layer connection. In particular, on the paper side over the prior art after Figures 1 and 2 an increase in the number of binding points to Layer connection per fiber support index (FSI after Beran) can be achieved.

In the following, in tabular form, calculations are reported on the number of binding points per layer support per fiber support index (FSI according to Beran) on the paper side, wherein "Unit" for unit, "Prior Art" for prior art and "According Invention" for according to the invention. parameter Unit Prior Art According Invention Paper side arising ... Fig. 1 Fig. 3 Number of warps in the upper fabric 1 cm 33.0 Chain diameter in the upper fabric mm 0.13 Fiber support relevant weft threads 1 cm 36.0 physically existing weft threads in the upper fabric 1 cm 48.0 54.0 Fiber support index (FSI) 1 177.8 binding points 1 / cpm ² 79.2 118.8 parameter Unit Prior Art According Invention Paper page according to ... Fig. 2 Fig. 6 Number of warps in the upper fabric 1 cm 33.0 Chain diameter in the upper fabric mm 0.13 Fiber support relevant weft threads 1 cm 36.0 physically existing weft threads in the upper fabric 1 cm 54.0 60.0 Fiber support index (FSI) 1 177.8 binding points 1 / cm ² 118.8 158.4

Claims (15)

1. Paper machine screen, in particular sheet forming screen,
   formed as a transverse thread-bound multi-layer fabric having an upper fabric layer comprising a first weave and a lower fabric layer comprising a second weave,
   wherein the multi-layer fabric has a total repeat which includes:

   upper longitudinal threads (1, 3, 5, 7, etc.), which extend exclusively in the upper fabric layer,

   lower longitudinal threads (2, 4, 6, 8, etc.), which extend exclusively in the lower fabric layer,

   the ratio of upper longitudinal threads to lower longitudinal threads being 1:1,

   the lower longitudinal threads having a diameter which is greater than or equal to the diameter of the upper longitudinal threads,

   upper transverse threads (101, 102, 109, 110, 117, 118, etc.; 404, 411, 418, 425, etc.) which extend exclusively in the upper fabric layer and which are interwoven with the upper longitudinal threads, thereby partially forming the first weave,

   lower transverse threads (103, 108, 111, 116, 119, 124, etc.; 403, 405, 410, 412, 417, 419, etc.) which extend exclusively in the lower fabric layer and are interwoven with the lower longitudinal threads, thereby completely forming the second weave,

   wherein the lower transverse threads have a diameter which is greater than the diameter of the upper transverse threads, and

   binding transverse threads (104-107, 112-115, 120-123, etc.; 406-409, 413-416, 420-423, etc.) which respectively extend both in the upper fabric layer and in the lower fabric layer and hereby bind the lower fabric layer to the upper fabric layer,

   wherein, within the total repeat, the binding transverse threads form functional transverse thread pairs (104+105, 106+107, 112+113, 114+115, etc.; 406+407, 408+409, 413+414, 415+416, etc.) of respectively two binding transverse threads arranged directly next to each other,

   wherein the two binding transverse threads of a respective functional transverse thread pair alternately complete the first weave and, in doing so, respectively extend over one or more upper longitudinal threads, thereby forming an imaginary upper transverse thread, and

   wherein the two binding transverse threads of a respective functional transverse thread pair alternately bind the lower fabric layer with the second weave completely formed by the lower longitudinal threads and the lower transverse threads to the upper fabric layer by the respective binding transverse thread of a respective functional transverse thread pair extending under at least one lower longitudinal thread during its course in the lower fabric layer within the total repeat,

   characterized in that,

   in the total repeat, the functional transverse thread pairs in the upper fabric layer, seen in a longitudinal direction, are arranged in groups (A-E, A-J) of respectively two or more functional transverse thread pairs arranged immediately next to each other, wherein two successive groups are respectively separated from each other by one or two or more upper transverse threads.
2. Paper machine screen according to claim 1, wherein,
   in the total repeat, the functional transverse thread pairs in the upper fabric layer, seen in a longitudinal direction, are arranged in groups (A-E, A-J) of exactly two functional transverse thread pairs arranged immediately next to each other and/or
   in the total repeat in the upper fabric layer, two successive groups are respectively separated from each other by exactly one or respectively by exactly two upper transverse threads.
3. Paper machine screen according to claims 1 or 2, wherein, in the total repeat, the functional transverse thread pairs in the lower fabric layer, seen in a longitudinal direction, are also arranged in groups (A'-E', A'-J') of two or more functional transverse thread pairs arranged immediately next to each other, wherein one or two or more lower transverse threads are respectively arranged between two successive groups of functional transverse thread pairs.
4. Paper machine screen according to claim 3, wherein,
   in the total repeat, the functional transverse thread pairs in the lower fabric layer, seen in a longitudinal direction, are arranged in groups (A'-E', A'-J') of exactly two functional transverse thread pairs arranged immediately next to each other and/or
   in the total repeat in the lower fabric layer, two successive groups are respectively separated from each other by exactly two lower transverse threads.
5. Paper machine screen according to any one of the preceding claims, wherein, in the total repeat, all binding transverse threads (104-107) of a respective group (E) of functional transverse thread pairs in the lower fabric layer between the same two corresponding lower successive transverse threads (103, 108) in longitudinal direction bind the lower fabric layer to the upper fabric layer and/or wherein in the lower fabric layer, the interspaces formed between the lower transverse threads, seen in a longitudinal direction, are alternatingly occupied or not occupied with bindings by the binding transverse threads of a respective group of functional transverse thread pairs.
6. Paper machine screen according to any one of the preceding
   claims, wherein the two binding transverse threads of a respective transverse thread pair alternately bind the lower fabric layer to the upper fabric layer by the respective binding transverse thread of the respective functional transverse thread pair extending under exactly one lower longitudinal thread during its course in the lower fabric layer within the total repeat, and/or wherein, within the respective group of functional transverse thread pairs, each binding transverse thread in the lower fabric layer extends under another lower longitudinal thread.
7. Paper machine screen according to any one of the preceding claims, wherein the first weave is a plain weave formed in longitudinal direction by the upper longitudinal threads and in transverse direction by the upper transverse threads and by the imaginary upper transverse threads that are formed by the functional transverse thread pairs and/or wherein the total repeat and/or the repeat of the upper fabric layer comprises 8, 10 or 12 upper longitudinal threads and/or wherein the second weave is a 5-shaft weave or a 10-shaft weave in which the course of the respective lower transverse thread is repeated in a transverse direction after 5 and 10 lower longitudinal threads, respectively, wherein the course of the respective transverse thread, e.g. is over a lower longitudinal thread and under four successive lower longitudinal threads or, e.g. is over two successive lower longitudinal threads and under eight successive lower longitudinal threads.
8. Paper machine screen according to any one of the preceding claims, wherein in the total repeat, each lower longitudinal thread is in total bound by two binding transverse threads or four binding transverse threads.
9. Paper machine screen according to any one of the preceding claims, wherein the total repeat comprises:

   10 upper longitudinal threads,

   10 lower longitudinal threads,

   10 upper transverse threads,

   10 lower transverse threads and

   20 binding transverse threads forming 10 functional transverse thread pairs,

   or wherein the total repeat comprises:

   10 upper longitudinal threads,

   10 lower longitudinal threads,

   10 upper transverse threads

   20 lower transverse threads and

   40 binding transverse threads forming 20 functional transverse thread pairs.
10. Paper machine screen according to any one of the preceding claims, wherein
    in the total repeat, in particular in the entire multilayer fabric, all longitudinal threads extending in the upper fabric layer are upper longitudinal threads which extend exclusively in the upper fabric layer, and/or
    in the total repeat, in particular in the entire multilayer fabric, all longitudinal threads extending in the lower fabric layer are lower longitudinal threads which extend exclusively in the lower fabric layer, and/or
    in the total repeat, in particular in the entire multilayer fabric, the upper fabric layer and the lower fabric layer are connected to each other exclusively by the binding transverse threads arranged to form functional transverse thread pairs.
11. Paper machine screen according to any one of the preceding claims, wherein the upper transverse threads are made of polyester and the binding transverse threads are made of polyamide.
12. Paper machine screen according to any one of the preceding claims, wherein the binding transverse threads are smaller in diameter than the lower transverse threads, and wherein the binding transverse threads in particular are of the same diameter as the upper transverse threads and/or the same diameter as the upper longitudinal threads.
13. Paper machine screen according to any one of the preceding claims, wherein the total repeat in the upper fabric layer, e.g. also in the lower fabric layer, comprises five groups (A-E) or ten groups (A-J) of functional pairs.
14. Paper machine screen according to any one of the preceding claims, wherein in the total repeat, the ratio of upper transverse threads, including functional transverse thread pairs, to lower transverse threads is greater than 1, in particular 2:1, e.g. 20:10, or 3:2, e.g. 30:20.
15. Paper machine screen according to any one of the preceding claims, wherein in the total repeat, each functional transverse thread pair forms exactly two intersections and/or wherein the intersections of all functional transverse thread pairs are distributed evenly to the upper longitudinal threads within the total repeat, so that the same number of intersections is positioned under each upper longitudinal thread, for example exactly two or exactly four.

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