EP2470716B1 - Forming fabric - Google Patents

Description

The invention relates to a multi-ply web forming screen as used in the papermaking process in the sheet forming zone of a wet end of a paper machine for dewatering a pulp suspension.

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

By pulp suspension is meant 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 distribute evenly in the water, which has an advantageous effect on the quality of the sheet to be formed.

Within the sheet forming zone, ie 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 screens, so that the dewatering can take place simultaneously through both screens, whereby the filtration process and thus also the production speed of the paper machine are considerably 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 fabric is required, ie a high uniformity of the sheet forming screen.

In recent years, multi-layer paper machine screens have been proven for such applications, which have two differently shaped sides, which are adapted to the particular application. 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, from the bottom of a Lower tissue is formed. 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 and a transverse direction, wherein the machine direction (in English MD for "machine direction") the direction of the paper web and thus the direction of the paper machine screen is understood, and wherein the transverse direction (in English CMD for "cross machine direction "), sometimes also called 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 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. With regard to the fiber support but also with regard to the marking tendency of the wire, the simplest and at the same time oldest basic weave of textile technology, the so-called plain weave, has proven itself for the upper fabric and thus for the paper side. In this binding, whose repeat (= smallest repetitive unit of binding) of exactly two warp threads (usually the warp threads are the longitudinal threads / machine direction threads of the screen formed) and two weft threads (usually the weft threads, the transverse threads of the sieve is formed), the threads are connected in a particularly intimate and uniform manner to a fabric. 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 for the connection of two fabric layers are described, of which one approach provides for the use of additional, separate binding threads, which extend in the longitudinal or transverse direction. According to this approach, two finished, fully formed fabric layers are connected to each other via separate, non-woven binding threads, which binding threads do not contribute to the construction of the respective fabric layer binding / are needed. 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 with warp threads of Bind upper and lower tissue warp threads, 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 in addition to the fabric-forming threads in the fabric structure, with little space for such separate binding threads is provided especially in the 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, can not produce high quality paper with such a modified fabric / sieve.

An alternative is the use of at least two transverse threads, which interact as a so-called functional transverse thread pair. One or both of the transverse threads of a functional pair run alternately in the upper and lower tissues. The two transverse threads of a functional pair can form a virtually uninterrupted transverse thread of a paper-side plain weave, ie an upper composite transverse thread. Those thread sections of the functional pair that are not needed for the formation of the paper-side virtually uninterrupted cross-thread, run inside the tissue and can be used to attach the lower tissue to the upper tissue. 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, 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 , An advantage of this solution is that the binding threads and the transverse threads forming the upper fabric can have the same diameter, whereby the uniformity of the paper side can be increased. Furthermore, the use of materials is kept within limits. On the other hand, however, the bond strength is reduced. In addition, with this approach, internal wear and associated ply separation could not be sufficiently avoided. By deflecting the screen on rollers and dewatering elements in the paper machine, the screen is bent in the longitudinal direction. One of the two fabric layers is always compressed, whereas the other is stretched. It comes to friction on the insides of the two individual layers and thus to internal wear. In addition, the cross-oriented binding threads are slightly moved in the tissue, which also creates friction between them and the threads integrated in one layer and thus wear.

Another alternative is the connection of the layers by so-called. Functional longitudinal thread pairs. If the two layers of fabric are penetrated by threads that lie in the main bending direction, it comes to compensation the differences in length within very short distances. The possibility of inner relative movement is reduced to a level that is no longer relevant in practice. In this context, the in DE 100 30 650 C1 and US 2007/0157988 described solutions in practice that with the connection described there a running side to a paper-side plain weave by means of functional longitudinal thread pairs no more ply separation occurs. Due to the long floatation of the cross-directional yarns, the number and distribution of the so-called warp knitting points and the division of paper-to-machine direction yarns, these fabrics reach their limits in terms of marking in paper, water content in the fabric and fiber support and can hardly be used for light weight, graphic Papers are used.

EP 0 069 101 , which discloses a sheet forming according to the preamble of claim 1, and EP 093 096 also show a ply connection via functional longitudinal thread pairs.

EP 1 767 692 A2 discloses a multi-ply fabric in which a paper-side plain weave is tied to a run-side 4-shaft weave. In the upper fabric are alternately provided only in the upper fabric extending upper longitudinal thread and a functional pair of longitudinal threads. The respective upper longitudinal thread runs above two pairs of lower longitudinal threads which run exclusively in the lower fabric. The respective functional pair of longitudinal threads on the one hand forms an upper composite longitudinal thread in the upper fabric and, on the other hand, binds the lower fabric to the left and right of a lower longitudinal thread, which is arranged below the upper composite longitudinal thread and runs exclusively in the lower fabric. The lower fabric is made entirely of lower transverse threads and formed lower longitudinal threads and is connected by the meantime in the lower fabric thread section of the functional longitudinal thread pairs only to the upper fabric (the tying thread section acts as a separate, non-woven binding thread). The fabric has a longitudinal thread repeat of eighteen longitudinal threads, three of which are formed as upper longitudinal threads and nine as lower longitudinal threads, with the remaining six longitudinal threads forming three functional pairs. Depending on the definition (see below) results in a longitudinal thread ratio of 2: 3 (6: 9) or 1: 2 (6:12) (looking at the paired juxtaposed lower longitudinal threads as each exactly one lower longitudinal thread so there is a ratio of 1: 1 (6: 6) or 2: 3 (6: 9)).

Similar solutions are in WO 2004/085740 A2 and WO 2004/085741 A1 described, wherein WO 2004/085740 A2 shows a fabric with a longitudinal thread repeat of 20 threads distributed over four upper longitudinal threads, four functional pairs and eight lower longitudinal threads. This in WO 2004/085741 A1 The fabric shown has a longitudinal thread repeat of 16 threads distributed among four upper longitudinal threads, four functional pairs, and four lower longitudinal threads to give a 2: 1 (8: 4) or 1: 1 (8: 8) longitudinal thread ratio. In both fabrics, the lower fabric is connected by thread sections of the functional pairs only to the upper fabric, ie, the lower fabric is completely and finally formed by lower longitudinal threads and lower transverse threads.

In EP 1 826 316 A2 a fabric is described whose longitudinal thread repeat consists of four upper longitudinal threads, twelve lower longitudinal threads and four functional pairs (ie a longitudinal thread repeat of 24 threads). The upper chains and the functional pairs form a paper-side canvas that is tied to a complete / complete bottom using functional pairs. At least three different warp systems are required for producing the fabric. The upper longitudinal threads and the functional pairs are arranged alternately, resulting in a superimposition of the paper-side bond pattern with the two different Oberkettsystemen.

EP 1 527 229 B1 and EP 1 220 964 B1 each reveal a three-warp warp knitting thread whose warp threads each run in the upper fabric and the lower fabric.

The object of the present invention is to provide a sheet forming screen of a multi-layered fabric, which is easy to manufacture and meets the requirements described above, i. e.g. has a high fiber support, high mechanical stability, low tendency to march and a stable layer connection.

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

According to the invention, the forming wire is formed of a multi-ply fabric having a longitudinal thread repeat of sixteen longitudinal threads, of which four longitudinal threads are formed as upper longitudinal threads and eight longitudinal threads as lower longitudinal threads. The remaining four longitudinal threads form two functional longitudinal thread pairs of two longitudinal threads arranged side by side.

According to a first embodiment of the invention, each of the four longitudinal threads which form the two functional longitudinal thread pairs extends both in the upper fabric layer and in the lower fabric layer, whereby the upper fabric layer is securely connected to the lower fabric layer.

According to the first embodiment of the invention, the upper longitudinal threads form together with running in the upper fabric layer transverse threads partially the binding of the upper fabric layer (this is eg the paper-side binding), the eight lower longitudinal threads together with extending in the lower fabric layer transverse threads partially the bond the lower fabric layer (this is eg the running side binding), and the two functional longitudinal thread pairs formed by the remaining four longitudinal threads complete both the binding of the upper fabric layer and the binding of the lower fabric layer. The longitudinal threads of the two functional pairs form two upper composite longitudinal threads and two lower composite longitudinal threads, which fit into the respective weave pattern.

According to a second embodiment of the invention, at least one of the four longitudinal threads, which form the two functional longitudinal thread pairs, extends both in the upper fabric layer and in the lower fabric layer, whereby the upper fabric layer is connected to the lower fabric layer. Those longitudinal threads of the two longitudinal thread pairs, which do not run in both fabric layers, run alternately in the upper layer and between the two layers, ie alternately in the upper layer and in the fabric interior. Preferably proceed Also in the second embodiment of the invention, all four longitudinal threads which form the two functional longitudinal thread pairs, both in the upper fabric layer and in the lower fabric layer, so that a reliable connection of the fabric layers is ensured.

According to the second embodiment of the invention, the upper longitudinal threads, together with transverse threads running in the upper fabric layer, partially form the binding of the upper fabric layer (this is, for example, the paper-side binding), and the eight lower longitudinal threads already complete, together with transverse threads extending in the lower fabric layer the binding of the lower fabric layer (this is eg the running side binding). The two longitudinal threads of each longitudinal thread pair complete the binding of the upper fabric layer alternately. The longitudinal threads of the two functional pairs thus form two upper Verbündlängsfäden, which complete the binding of the upper fabric layer. Furthermore, the at least one longitudinal thread, which extends both in the lower and in the upper fabric layer, binds the lower fabric layer, which is completely formed by the lower longitudinal threads, to the upper fabric layer as a separate binder thread. If both longitudinal threads of a functional pair run both in the upper and in the lower fabric layer, the two longitudinal threads of a longitudinal thread pair alternately complete the first binding and, in turn, bind the lower fabric layer completely formed by the lower longitudinal threads to the upper fabric layer. That is, in the latter case, those thread portions of a functional pair that are not being used to form the upper composite longitudinal thread bind at least one sub-fabric transverse thread as a separate binder thread, thereby forming the lower fabric layer to connect with the upper fabric layer. This has the advantage of an increased number of binding points and thus a stronger layer connection. In addition, the two threads of a functional pair in the latter case, the same thread length, resulting in a uniform interweaving.

According to the invention, the connection of the upper layer with the lower layer thus takes place (at least in part) via functional longitudinal thread pairs, which brings about the advantages described above with respect to a layer connection by means of separate connecting threads or by means of functional transverse thread pairs. However, the invention is intended to Such screens may also be included in which, in addition to the functional longitudinal thread pairs, e.g. separate connecting threads are provided.

Because the fabric has a longitudinal thread repeat of 16 longitudinal threads, as well as due to the claimed distribution of sixteen longitudinal threads on four upper longitudinal threads, eight lower longitudinal threads and two functional pairs, the sheet forming according to the invention can be produced with a weaving machine, which with a shaft package of sixteen shafts and is equipped with two warp beams (if the longitudinal threads are formed by warp threads). In this case, the sixteen longitudinal threads can be divided into two warp beam units of eight threads each, wherein the first unit comprises the eight lower longitudinal threads of the respective rapport, and wherein the second unit comprises the remaining eight longitudinal threads of the respective repeat. A weaving machine equipped with sixteen shafts and two warp beams is required for the production of a variety of other fabrics / sieves, so that the sieve according to the invention can easily be produced with an existing weaving machine. Ie, for the production of the Sieves according to the invention, it is not necessary to turn off a separate loom or retrofit an existing loom (eg by adding or removing shafts). Rather, the inventive sieve can be made in the production breaks of another 16-shaft sieve without prior conversion of the machine.

From the claimed distribution / assignment of the sixteen longitudinal threads results in a ratio of upper longitudinal threads to lower longitudinal threads of 4: 8 or 1: 2. For the first embodiment of the screen according to the invention, two of the four longitudinal threads of the two functional pairs of the lower and the upper fabric layer can be attributed, since these four longitudinal threads contribute to fabric formation in both layers and form two composite longitudinal threads, so that a total of a longitudinal thread ratio of 6:10 or 3: 5 results. If in the second embodiment of the screen according to the invention only the two upper composite longitudinal threads are taken into account in the calculation of the longitudinal thread ratio, the result is a longitudinal thread ratio of 6: 8 or 3: 4. If the four longitudinal threads are evenly distributed on the upper fabric and the lower fabric (although the at least one longitudinal thread in the lower fabric layer functions merely as a separate binder thread), a ratio of 6:10 or 3: 5 is obtained, as for the first embodiment. The described longitudinal thread ratio of 3: 5 or 3: 4 and the concomitant reduced amount of longitudinal thread in the upper fabric layer, of which usually the paper side is formed, favors the formation of paper-side transverse mesh whose extension in the transverse direction is greater than in Sieve longitudinal direction. Such transverse meshes allow a high fiber support, as the paper fibers through the work of Paper machine and the Strömüngsverhältnisse in the headbox thereof are mainly aligned in the machine direction. That is, with a constant total number of threads, the screen surface has comparable fiber permeability and comparable design higher fiber support capacity. A more cross-oriented paper side of the screen thus provides better fiber support. The comparatively large number of lower longitudinal yarns compensates for a paper-side strength reduction and machine-direction stretch increase associated with the formation of the transverse stitches, ie the reduction in strength and increase in the wire strain in the critical machine direction caused by a reduction in paper-side longitudinal yarns can be increased Number of running side longitudinal threads are compensated.

According to one embodiment of the invention, exactly two upper longitudinal threads and / or exactly four lower longitudinal threads are always arranged in the fabric between two functional longitudinal thread pairs, whereby a particularly uniform paper side or running side can be represented.

According to a further embodiment of the invention, the upper longitudinal threads and the longitudinal threads of the functional pairs have substantially the same diameter. If the longitudinal threads are formed by warp threads, the upper longitudinal threads and the longitudinal threads of the functional pairs can therefore be wound onto a common warp beam. The diameter of the lower longitudinal threads may, for example, be equal to the diameter of the upper longitudinal threads and the longitudinal threads of the functional pairs (in particular in the first embodiment of the invention). Alternatively, the diameter of the lower Longitudinal threads are greater than the diameter of the upper longitudinal threads and the longitudinal threads of the functional pairs (in particular in the second embodiment of the invention).

According to a further embodiment of the invention, all transverse threads running in the upper fabric are designed as upper transverse threads, which are arranged exclusively in the upper fabric, and / or all transverse threads running in the lower fabric are designed as lower transverse threads, which are arranged exclusively in the lower fabric.

The transverse threads running in the lower fabric layer may e.g. have a larger diameter than the transverse threads running in the upper fabric layer.

The ratio of transverse threads running in the upper fabric to transverse threads running in the lower fabric may be e.g. greater than 1, e.g. at least or exactly 2: 1 or e.g. at least or exactly 3: 2. The greater number of transverse threads running in the upper fabric favors the formation of the paper-side transverse stitches described above. However, the invention is not limited to a certain number of transverse threads running in the lower and upper fabrics.

The first binding (= binding of the upper fabric layer) may eg be a plain weave, and the second weave (= binding of the lower fabric layer) may, for example, be a 5-shaft binding (in particular in the first embodiment / alternative of the invention; Longitudinal threads of the two functional pairs of two lower composite longitudinal threads, which are considered for the designation / assessment of the second binding as two lower longitudinal threads) or a 4-shaft binding (especially in the second embodiment / alternative of Invention) (4-shaft binding or 5-shaft binding means that the binding can be produced with 4 or 5 shafts, in other words, the repeat of such a binding has 4 or 5 warp threads or longitudinal threads). However, the invention is not limited to a particular binding of the upper tissue or a specific binding of the lower tissue. For example, upper fabric and lower fabric may also have the same binding, eg a plain weave.

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

Here are some terms used in this application:

As longitudinal yarns threads of the screen / fabric are referred to, which are arranged 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 shots.

As transverse threads threads of the screen / fabric are referred to, which are arranged transversely to the direction of the paper machine. In the flat woven screen, the transverse threads are formed by the shots. Round fabrics, on the other hand, realize the transverse threads with the chains of the loom.

The fabric layer is understood to mean a single-layer fabric consisting of transverse threads and longitudinal thread (or chains and wefts).

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 never leave the upper fabric, i. they do not change into the lower tissue.

Upper transverse threads are those threads which are exclusively in the upper fabric and are interwoven there with the upper longitudinal threads (as well as the longitudinal threads of the functional pairs). Upper transverse threads never leave the upper fabric, i. they do not change into the lower tissue.

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 never leave the lower tissue, ie they do not change into the upper tissue.

Lower transverse threads are those threads which are located exclusively in the lower fabric and there are interwoven with the lower longitudinal threads (in the first embodiment of the invention also with the longitudinal threads of the functional pairs). Lower transverse threads never leave the lower tissue, i. they do not change into the upper tissue.

A functional pair of longitudinal threads consists of two directly adjacent longitudinal threads whose position in the mesh / fabric is not limited to a fabric layer, ie the longitudinal threads of a functional pair do not run exclusively in a fabric layer. As a rule, both longitudinal threads of a functional longitudinal thread pair extend both in the lower fabric and in the upper fabric, ie the longitudinal threads of a longitudinal thread pair change between the upper and lower fabric layers (in the first embodiment of the invention and in an alternative of the second embodiment of the invention). However, one or both longitudinal threads of a functional pair can also change between one of the two layers and the tissue interior (according to a second alternative of the second embodiment). According to the first embodiment of the invention, the two threads of a functional pair together fulfill both the task of an upper longitudinal thread (eg a top chain) and a lower longitudinal thread (eg a lower chain) and additionally connect the different layers of fabric through their course. An upper longitudinal thread thus formed and a lower longitudinal thread formed in this way may also be referred to as "upper or lower composite longitudinal threads". According to the second embodiment of the invention, the two threads of a functional pair together fulfill the function of an upper fabric-owned longitudinal thread ("upper composite longitudinal thread") and possibly that of a lower non-woven binding thread.

A longitudinal thread repeat is the smallest repeating unit of longitudinal threads in the fabric. If the longitudinal threads are formed by warp threads, then the number of threads of the longitudinal thread repeat corresponds to the number of shafts needed to manufacture the fabric.

• Fig. 1 einen schematisch dargestellten, vollständigen Rapport eines Gewebes gemäß der vorliegenden Erfindung in perspektivischer Ansicht, wobei die obere Gewebelage mit (A) und die untere Gewebelage mit (B) bezeichnet ist,
• Fig. 2 in vereinfachter Darstellung die Aufteilung der sechzehn Längsfäden auf die beiden Gewebelagen, wobei die Querfäden weggelassen sind,
• Fig. 3 eine Stirnansicht des Gewebes aus Fig. 1 (zu sehen sind die Querschnittfläche der Längsfäden sowie der Querfadenverlauf),
• Fig. 4 eine perspektivische Ansicht des Gewebes aus Fig. 1, in der das Verhältnis der Längsfäden (bzw. der Kettfäden) von 6 zu 10 sowie der prinzipielle Verlauf der papierseitigen und laufseitigen Querfäden der Bindung aus Fig. 1 erkennbar ist,
• Fig. 5 eine schematische Draufsicht auf die Papierseite des Gewebes aus Fig. 1, wobei die darunter befindliche Laufseite weggelassen ist,
• Fig. 5a das Bindungsbild des Obergewebes, wobei die Einbindungsstellen, an denen ein oberer Querfaden von einem oberen Längsfaden oder einem oberen Verbundlängsfaden eingebunden wird, mit einem "x" markiert sind,
• Fig. 6 eine schematische Draufsicht auf die untere Gewebelage des Gewebes aus Fig. 1 (ohne darüber befindliche Papierseite),
• Fig. 6a das Bindungsbild des Untergewebes, wobei die Einbindungsstellen, an denen ein unterer Querfaden von einem unteren Längsfaden oder einem unteren Verbundlängsfaden eingebunden wird, mit einem "x" markiert sind,
• Fig. 7 eine schematische Draufsicht auf das gesamte Gewebe aus Fig. 1, d.h. eine Ansicht von oben auf sowohl die Papierseite (Obergewebe) als auch die darunter befindliche Laufseite (Untergewebe), einschließlich der Wechselstellen der funktionalen Paare,
• Fig. 8 eine schematische Ansicht betreffend die Einreihung der sechzehn Kettfäden eines Rapports in die sechzehn Schäfte einer Webmaschine zur Realisierung des Gewebes aus den Figuren 1 bis 7,
• Fig. 9 eine schematische Draufsicht auf die obere Gewebelage eines mehrlagigen Gewebes gemäß einer zweiten Ausführungsform der Erfindung, wobei die untere Gewebelage weggelassen ist,
• Fig. 9a das Bindungsbild des Obergewebes, wobei die Einbindungsstellen, an denen ein oberer Querfaden von einem oberen Längsfaden oder einem oberen Verbundlängsfaden eingebunden wird, mit einem "x" markiert sind,
• Fig. 10 eine schematische Draufsicht auf die untere Gewebelage des mehrlagigen Gewebes gemäß der zweiten Ausführungsform der Erfindung,
• Fig. 10a das Bindungsbild des Untergewebes, wobei die Einbindungsstellen, an denen ein unterer Querfaden von einem unteren Längsfaden eingebunden wird, mit einem "x" markiert sind, und wobei die Anbindungsstellen, an denen das Untergewebe mittels eines Längsfadens eines funktionalen Längsfadenpaares an das Obergewebe angebunden wird, mit einem "-" markiert sind, und
• Fig. 11 eine schematische Stirnansicht des Gewebes gemäß der zweiten Ausführungsform der Erfindung.

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

• Fig. 1 a schematically illustrated, complete repeat of a fabric according to the present invention in a perspective view, wherein the upper fabric layer with (A) and the lower fabric layer with (B) is designated,
• Fig. 2 in a simplified representation, the distribution of the sixteen longitudinal threads on the two fabric layers, wherein the transverse threads are omitted,
• Fig. 3 an end view of the tissue Fig. 1 (You can see the cross-sectional area of the longitudinal threads and the transverse thread course),
• Fig. 4 a perspective view of the tissue Fig. 1 , in which the ratio of the longitudinal threads (or of the warp threads) of 6 to 10 and the basic course of the paper side and running side transverse threads of the binding Fig. 1 it is recognizable
• Fig. 5 a schematic plan view of the paper side of the fabric Fig. 1 with the underlying running side omitted,
• Fig. 5a the weave pattern of the upper fabric, wherein the binding points at which an upper transverse thread is bound by an upper longitudinal thread or an upper composite longitudinal thread are marked with an "x",
• Fig. 6 a schematic plan view of the lower fabric layer of the fabric Fig. 1 (without the paper side above),
• Fig. 6a the weave pattern of the lower fabric, wherein the bonding points at which a lower transverse thread is bound by a lower longitudinal thread or a lower composite longitudinal thread are marked with an "x",
• Fig. 7 a schematic plan view of the entire tissue Fig. 1 ie a view from above of both the paper side (upper fabric) and the lower side (lower fabric), including the change points of the functional pairs,
• Fig. 8 a schematic view relating to the classification of the sixteen warp threads of a rapport in the sixteen shafts of a loom for the realization of the fabric of the FIGS. 1 to 7 .
• Fig. 9 a schematic plan view of the upper fabric layer of a multi-layer fabric according to a second embodiment of the invention, wherein the lower fabric layer is omitted,
• Fig. 9a the weave pattern of the upper fabric, wherein the binding sites, where an upper transverse thread of a upper longitudinal thread or upper composite longitudinal thread is marked with an "x",
• Fig. 10 a schematic plan view of the lower fabric layer of the multilayer fabric according to the second embodiment of the invention,
• Fig. 10a the binding pattern of the lower fabric, wherein the binding points at which a lower transverse thread is bound by a lower longitudinal thread are marked with an "x", and wherein the attachment points at which the lower fabric is connected to the upper fabric by means of a longitudinal thread of a functional longitudinal thread pair, marked with a "-", and
• Fig. 11 a schematic end view of the fabric according to the second embodiment of the invention.

The FIGS. 1 to 7 show a fabric according to a first embodiment of the invention. The fabric is a multi-ply fabric and can be used, for example, as a sieve, for example as a forming fabric as needed in the papermaking process. The upper fabric layer is identified by the reference numeral (A), whereas the lower fabric layer is indicated by the reference symbol (B). For example, the upper layer may form the paper side of a screen, and the lower layer may form the running side of the screen, for example.

In the FIGS. 1 to 7 exactly one repeat of the tissue is shown, ie the smallest repeating unit of the entire tissue. Like from the FIGS. 1 to 7 it can be seen, the repeat of the fabric according to this embodiment has exactly sixteen longitudinal threads (= Machine direction threads) (see eg FIGS. 2 to 4 ) and exactly thirty transverse threads (= cross machine direction threads) (cf., eg FIGS. 5 to 7 ) on. The longitudinal threads can be formed, for example, by warp threads, and the transverse threads can be formed, for example, by weft threads. The fabric shown can thus be produced with a number of sixteen shafts (corresponding to the longitudinal thread repeat of 16 threads) (cf. FIG. 8 ).

The sixteen longitudinal threads are divided as follows on the lower fabric layer and the upper fabric layer. The four longitudinal threads 11, 12, 13 and 14 extend exclusively in the upper fabric layer (see, eg Fig. 5 ) and are therefore referred to below as upper longitudinal threads. The eight longitudinal threads 31, 32, 33, 34, 35, 36, 37 and 38, however, run exclusively in the lower fabric layer (see, eg Fig. 6 ) and are therefore referred to below as lower longitudinal threads.

The remaining four longitudinal threads 21, 22, 23 and 24 of the fabric tap are designed as two so-called functional pairs. The two immediately adjacent longitudinal threads 21 and 22 form a first functional pair, and the two immediately adjacent longitudinal threads 23 and 24 form a second functional pair. The four longitudinal threads 21, 22, 23 and 24, which form the two functional pairs, run both in the lower fabric layer and in the upper fabric layer, respectively. these four longitudinal threads 21, 22, 23 and 24 alternate between the upper and lower fabric layers.

Such as out FIG. 5 it can be seen, there is always exactly one of the two longitudinal threads of a functional Couple on the paper side. That is, when a first of the two longitudinal threads of a pair is on the paper side, the other of the two longitudinal threads of the functional pair is inside the fabric or on the running side. As soon as the one longitudinal thread of the pair leaves the paper side, ie, changes into the interior of the fabric or on the running side, the other longitudinal thread passes in its place and runs on the paper side. In the embodiment shown, each longitudinal thread of a functional pair extends over a distance of nine upper transverse threads on the paper side before it leaves. Thus, the longitudinal thread 22 alternately passes over and under the nine transverse threads 104-112, and the longitudinal thread 21 runs alternately above and below the transverse threads 114-120 (of the repeat shown) and 101, 102 (of the adjacent repeat). The two functional pairs 21, 22 and 23, 24 thus form two "upper composite longitudinal threads". The upper fabric layer thus has four repeat longitudinal threads and two upper composite longitudinal threads per repeat (see Fig. 5 ). According to this embodiment, exactly two upper longitudinal threads 12, 13 are arranged between the two functional pairs 21, 22 and 23, 24 or between the two composite longitudinal threads. As further out FIG. 5 can be seen, takes place the change between the longitudinal threads of a pair of longitudinal yarn below an upper transverse thread (and above the lower transverse threads, as in FIG. 6 can be seen, ie between lower and upper layer or inside the fabric). The resulting so-called. Change points are in the Figures 5 and 6 denoted by A1, A2, B1 and B2. According to the embodiment shown, the change points of one functional pair are offset relative to the change points of the other functional pair by three upper transverse threads.

FIG. 5a shows the weave pattern of the upper fabric, it being well seen how the two longitudinal threads 21, 22 together form an upper composite longitudinal thread that fits into the binding pattern of the paper side, ie the upper composite longitudinal thread 21, 22 replaces an upper longitudinal thread, otherwise for training the paper-side plain weave would be needed. The same applies to the longitudinal threads 23, 24th

Such as out FIG. 6 it can be seen, according to this embodiment is also always exactly one of the two longitudinal threads of a functional pair on the running side. That is, when a first of the two longitudinal threads of a pair is on the running side, the other of the two longitudinal threads is on the paper side. As soon as the one longitudinal thread of the pair leaves the running side, the other longitudinal thread comes in its place and runs on the running side. In the embodiment shown, each longitudinal thread of a functional pair extends over a distance of five lower transverse threads on the running side before it leaves. The two functional pairs 21, 22 and 23, 24 thus simultaneously form two "upper composite longitudinal threads" and two "lower composite longitudinal threads". The lower fabric layer thus has per repeat eight lower longitudinal threads and two lower composite longitudinal threads (see Fig. 6 ). According to this embodiment, exactly four lower longitudinal threads 33, 34, 35, 36 are arranged between the two functional pairs 21, 22 and 23, 24 or between the two composite longitudinal threads.

Of the thirty transverse threads, twenty transverse threads 101 to 120 of the upper fabric layer or the paper side and ten transverse threads 201 to 210 of the lower fabric layer or the running side are assigned. The twenty transverse threads 101 to 120 of the upper layer have a smaller diameter than the ten transverse threads 201 to 210 of the lower layer. The twenty transverse threads 101 to 120 run exclusively in the upper fabric layer, and the ten transverse threads 201 to 210 run exclusively in the lower fabric layer. That is, none of the transverse threads 101 to 120 changes to the running side, and none of the transverse threads 201 to 210 changes to the paper side. In the following, the transverse threads 101 to 120 are therefore referred to as upper transverse threads and the transverse threads 201 to 210 as lower transverse threads. It should be noted, however, that the invention is not restricted either to the number of upper and lower transverse threads shown or to the ratio of upper transverse threads to lower transverse threads shown (in this case 2: 1). Also, the diameter of the upper transverse threads, for example, be equal to or greater than the diameter of the lower transverse threads.

As in FIG. 5 4, the four upper longitudinal threads 11-14 and the two upper composite longitudinal threads formed by the two functional pairs 21, 22 and 23, 24 form a plain weave together with the twenty upper transverse threads 101-120 on the paper side and in the upper fabric layer, respectively , Thus, the upper longitudinal thread 11 runs alternately over and under one of the upper transverse threads 101-120 (sequence / sequence = 1 times over, 1 * times under). The same applies to the upper composite longitudinal thread 21, 22, wherein the course is offset above and below the upper transverse threads relative to the course of the upper longitudinal thread 11 to an upper transverse thread. That is, while the upper longitudinal thread 11 passes over the upper transverse thread 101 and under the upper transverse thread 102, the upper composite longitudinal thread 21, 22 extends below the upper transverse thread 101 and above the upper transverse thread 102. The upper longitudinal thread 12 and the upper composite longitudinal thread 23, 24 have the same course as the upper longitudinal thread 11, and the course of the upper longitudinal threads 13 and 14 with respect to the upper transverse threads 101-120 corresponds to that of the upper composite longitudinal thread 21, 22. In other words, each of the upper longitudinal threads and upper composite longitudinal threads binds every other upper transverse thread into the fabric. It is noted, however, that the invention is not limited to paper-side plain weave, although it has been found to be suitable. At the point indicated by the reference A1, the thread 21 dips into the interior of the fabric and changes to the lower layer. For this, the thread 22 changes at the point marked A1 on the paper side and "replaces" the thread 21 there. At the point indicated by the reference A2, the thread 22 then dives back into the interior of the fabric and changes to the lower layer. For this, the thread 21 changes back to the paper side at the point marked A2 and "replaces" the thread 22 there.

How out FIG. 6 As can be seen, the eight lower longitudinal threads 31-38 and the two lower composite longitudinal threads formed by the two functional pairs 21, 22 and 23, 24 together with the ten lower transverse threads 201-210 on the running side and in the lower fabric form a 5-shaft Binding off. However, the embodiment shown / training the running side is only one of several possible embodiments, ie, it can also be other side links provided, although the binding shown has been found suitable. Within the in FIG. 1 shown Geweberapports binds each of the lower longitudinal threads 31-38 and lower composite longitudinal threads 21, 22 and 23, 24 exactly two lower transverse threads and floats over the remaining eight lower transverse threads (see. Fig. 6a ). The Sequence / sequence is "over four lower transverse threads, below a lower transverse thread". Thus, for example, the lower longitudinal thread 31 binds the lower transverse threads 201 and 206 and floats over the lower transverse threads 202-205 and 207-210. The slope of in FIG. 6 shown 5-strong binding is two or two lower transverse threads. That is, the next longitudinal thread 32 (ie, the lower longitudinal thread 31 adjacent lower longitudinal thread) binds the lower transverse threads 203 and 208, and the subsequent lower composite longitudinal thread 21, 22 binds the lower transverse threads 205 and 210, etc. through the lower longitudinal threads 31, 32, 33, 34 and the lower composite longitudinal thread 21, 22 formed 5-shaft bond is repeated by the lower longitudinal threads 35, 36, 37, 38 and the lower composite longitudinal thread 23, 24. In other words, in FIG. 6 two longitudinal thread reports the run-side 5-shaft binding shown (as well as two Querfadenrapporte, so that a total of four repeats of the run-side binding are shown).

According to the in the Figures 1-7 As shown, therefore, both the binding of the upper fabric layer and the binding of the lower fabric layer by the two functional pairs 21, 22 and 23, 24 are completed. That is to say, the longitudinal threads 21, 22, 23, 24 (eg warp threads) are interwoven both with the upper transverse threads (eg upper shots) and with the lower transverse threads (eg lower shots) with completion of the respective fabric or the respective weave. In other words, the two functional pairs 21, 22 and 23, 24 contribute to the formation of the respective binding, in the illustrated embodiment to the paper-side plain weave and the running side 5-shaft weave. Further, the paper side and the running side are connected to each other by the two functional pairs 21, 22 and 23, 24. The longitudinal threads of the two functional pairs 21, 22 and 23, 24 serve as textile threads in the lower fabric and in the upper fabric and at the same time act as binding threads. Thus, the filaments of the functional pairs according to this embodiment are used both in the lower fabric and on the running side and in the upper fabric and on the paper side, respectively, as an essential component of the respective fabric. Their integration into the respective tissue not only serves to connect the lower tissue to the upper tissue but also to form functional binding points within the respective tissue.

The above-described completion of the paper side and running side binding by the two functional pairs is particularly from a synopsis of Figures 5 and 6 clear. So binds the thread 22 in FIG. 5 the upper transverse threads 104, 106, 108, 110 and 112 and thus completing the paper-side plain weave, while the thread 21 in FIG. 6 incorporates the lower transverse thread 205 and thereby completes the 5-shaft binding on the running side (without this integration, the transverse thread 205 would fall downwards out of the tissue since it is not bound by any of the lower longitudinal threads). When the thread 22 goes down to FIG. 6 To tie in the lower transverse thread 210, thereby completing the run-side binding, the thread 21 changes upward to engage the upper transverse threads 114, 116, 118 and 120, thereby completing the paper-side plain weave. Thus, the two longitudinal threads 21 and 22 alternately complete the paper-side weave (in this embodiment, a plain weave) and the run-side weave (a 5-shank weave in this embodiment).

FIG. 7 shows the two in FIG. 5 and FIG. 6 separated layers in an "assembly" drawing. Both layers can be seen in the view from above. The top layer represents the paper side of a forming screen.

As in FIG. 7 is shown in the plan view of the tissue is substantially always an upper longitudinal thread between two lower longitudinal threads. Thus, the upper longitudinal thread 11 lies in the plan view substantially between the two lower longitudinal threads 31, 32, the upper longitudinal thread 12 is substantially between the lower longitudinal threads 33, 34, the upper longitudinal thread 13 is substantially between the lower longitudinal threads 35, 36, and the upper longitudinal thread 14 lies substantially between the lower longitudinal threads 37, 38. This results in a ratio of upper to lower longitudinal threads of 4: 8 or 1: 2. If the four longitudinal threads 21, 22, 23, 24 of the functional pairs are distributed uniformly over the lower fabric layer and the upper fabric layer (since they contribute to fabric formation in both layers and form two composite longitudinal threads in each layer), the result is a longitudinal thread ratio of 6 : 10 or 3: 5 (cf. FIG. 2 ).

Like also out FIG. 7 is apparent, the formation of so-called cross-stitches (whose machine direction / longitudinal direction is smaller than in the transverse direction) on the paper side by the comparatively small number of upper longitudinal threads and upper composite longitudinal threads (resulting from the longitudinal thread ratio of 6:10 and 3: 5) ) favors. Such cross-stitches allow convenient support / support of the fibers contained in the pulp suspension. Due to the comparatively large number of lower longitudinal threads and lower composite longitudinal threads with the formation of the Cross-straightening paper-side strength reduction and increase the screen strain in the machine direction are compensated.

Like also out FIG. 7 can be seen, an upper transverse thread is arranged in plan view over each lower transverse thread. Furthermore, an upper transverse thread is always arranged between two lower transverse threads. This results in a ratio of upper to lower transverse threads of 20:10 or 2: 1. However, as explained above, this ratio can be varied. An increased number of upper transverse threads, however, favors the formation of the transverse meshes.

According to the in the FIGS. 1 to 7 In the embodiment shown, the diameter of the upper longitudinal threads 11-14 is equal to the diameter of the threads 21-24 of the functional pairs. As a result, on the one hand a uniform paper page can be obtained. The uniformity of the paper side is only slightly affected by the four change points A1, A2, B1 and B2 of the two functional pairs. With the shown ratio of four upper longitudinal threads to two functional pairs or two upper composite longitudinal threads, and especially with the shown distribution of upper longitudinal threads and functional pairs (two upper longitudinal threads between the functional pairs), the paper-side weave hardly ever becomes " disturbed, compared to paper-side bindings of the prior art, where exclusively upper composite longitudinal threads or alternately upper longitudinal threads and upper composite longitudinal threads are provided. On the other hand, the upper longitudinal threads 11-14 and the threads 21-24 of the functional pairs can be easily applied to the same warp beam (warp beam X2 in FIG FIG. 8 ).

The diameter of the lower longitudinal threads 31-38 can according to the in FIGS. 1 to 7 As shown embodiment, for example, be equal to the diameter of the upper longitudinal threads 11-14 and the threads 21-24 of the functional pairs, whereby a smooth running side can be obtained, which is interrupted only by the four change points A1, A2, B1 and B2.

In FIG. 2 To illustrate and greatly simplify again the functional division of the longitudinal threads on the paper side (A) and the running side (B) is shown. In this case, initially the impression can arise that the described fabric can already be produced from eight shafts or with a longitudinal thread repeat of 3: 5. As in FIG. 5 can be seen, the course of the upper longitudinal thread 11 but not equal to that of the upper longitudinal thread thirteenth

The FIGS. 1 . 3 and 4 show three-dimensional views of the fabric described or Blattbildungssiebes.

FIG. 8 shows a schematic representation of a loom for the production of the tissue after the FIGS. 1 to 7 , Shown are two warp beams X1 and X2. The first warp beam X1 carries the lower longitudinal yarns, and the second warp beam X2 carries the upper longitudinal yarns and the longitudinal yarns of the functional pairs. Of course, in FIG. 8 only a small portion of the two warp beams shown (corresponding to a Längsfadenapport), ie seen in the longitudinal direction of the warp beam X1 follows the thread 38 another thread 31, then another thread 32, etc. The thread 31 of the warp beam X1 is in the shaft S1 hung or passed through it. The just mentioned, not shown further thread 31 is also hooked into the shaft S1 (as well as all other threads 31 of the fabric). If the shaft S1 is raised, all threads 31 are raised with it, so that a weft thread can be guided under all the threads 31. In the same way, all the upper longitudinal threads 32 are hooked into the second shaft S2, all the upper longitudinal threads 33 are hooked into the eleventh shaft S11, etc. For the production of in the FIGS. 1 to 7 shown tissue (which in FIG. 8 is shown schematically and designated by the reference numeral X4), which has a longitudinal thread repeat of sixteen longitudinal threads is therefore - if the longitudinal threads are formed of warp threads - a shaft package X3 needed, which consists of sixteen shafts S1, S2, S3, ..., S16 consists.

That is, the 16 longitudinal threads are divided into two units of 8 threads each, with each unit having its own warp beam X1 and X2, respectively, and the threads being individually ranked according to their function in the shafts X3 of the loom. This results in a logical assignment of the warp threads according to their function, which was explained above.

With the described arrangement of a 16-shaft shaft package X3 in conjunction with two warp beams X1 and X2, a multiplicity of different fabrics can be produced, in particular those fabrics in which the connection of upper fabric and lower fabric takes place via functional longitudinal thread pairs. Examples of such fabrics are, for example, those in DE 100 30 650 C1 and that in WO 2007/087852 described sieve or tissue. Consequently, with the same weaving machine numerous fabrics / sieves can be produced without the weaving machine has to be rebuilt in the meantime.

The FIGS. 9 to 11 show a multi-ply fabric according to a second embodiment of the invention, which can be used, for example, as a sieve, for example as a forming screen as it is needed in the process of papermaking. In FIG. 9 In this case, the upper fabric layer in the plan view (ie the paper side of the screen) is shown, whereas FIG. 10 the lower fabric layer in plan view shows. FIG. 11 shows an end view of the multi-layer fabric.

In the Figures 9 and 10 is exactly a repeat of the tissue shown. As in the Figures 9 and 10 As shown, the repeat of the fabric according to this embodiment consists of exactly sixteen longitudinal threads (= machine direction threads) and exactly twenty transverse threads (= cross machine direction threads). The longitudinal threads can be formed, for example, by warp threads, and the transverse threads can be formed, for example, by weft threads. The fabric according to the second embodiment can thus be made as the fabric according to the first embodiment with a number of sixteen shafts, ie, for example, with the in FIG. 8 shown arrangement.

The sixteen longitudinal threads are divided as follows on the lower fabric layer and the upper fabric layer. The four longitudinal threads 11, 12, 13 and 14 are formed as upper longitudinal threads and extend exclusively in the upper fabric layer (see Fig. 9 ), whereas the eight longitudinal threads 31, 32, 33, 34, 35, 36, 37 and 38 are formed as lower longitudinal threads extending exclusively in the lower fabric layer (see Fig. 10 ). Of the remaining four longitudinal threads 21, 22, 23 and 24 of Geweberapports two functional pairs are formed, wherein the two immediately adjacent longitudinal threads 21 and 22 a first functional pair and the two immediately side by side arranged longitudinal threads 23 and 24 form a second functional pair. Each of the four longitudinal threads 21, 22, 23 and 24 extends both in the lower fabric layer and in the upper fabric layer, ie each of these four longitudinal threads 21, 22, 23 and 24 changes within a rapport between the upper and lower fabric layers.

As in the Figures 9 and 9a is shown, there is always exactly one of the two longitudinal threads of a functional pair on the paper side or in the upper fabric layer. That is, when one of the two longitudinal threads of a pair is on the paper side or in the upper fabric layer, the other of the two longitudinal threads of the functional pair is inside the fabric (ie between the upper and lower layers) or in the lower fabric layer. As soon as one longitudinal thread of the functional pair leaves the paper side, the other longitudinal thread comes in its place and runs on the paper side. In the embodiment shown, each longitudinal thread of a functional pair extends over a distance of five upper transverse threads on the paper side, thereby incorporating three transverse threads. The two functional pairs 21, 22 and 23, 24 thus form two "upper composite longitudinal threads", so that the upper fabric layer per longitudinal thread repeat of the fabric has four upper longitudinal threads and two upper composite longitudinal threads. According to this embodiment, exactly two upper longitudinal threads 12, 13 are arranged between the two functional pairs 21, 22 and 23, 24 or between the two composite longitudinal threads. The longitudinal thread change of the first longitudinal thread pair 21, 22 takes place below the upper transverse threads 101 and 107, that of the second longitudinal thread pair 23, 24 below the upper transverse threads 104 and 110. The resulting change points are in FIG. 9 denoted by the reference symbols A1, A2, B1 and B2. The Changing points of one functional pair are offset from the change points of the other functional pair by three upper transverse threads.

Like from the Figures 10 and 10a it can be seen, the one longitudinal thread portion of a functional longitudinal thread pair, which is currently not in the upper fabric layer binds the lower fabric layer to the upper fabric layer by at least one (in the example shown exactly below) undercut (in the plan view of the lower fabric layer) and thereby binds. The longitudinal thread of the functional longitudinal thread pair tying the lower fabric acts as a separate, "fabric-foreign" bonding thread, ie the thread tying the lower fabric does not contribute to the formation of the running side binding or to the formation of the lower fabric. That is, according to this embodiment, the two functional pairs 21, 22 and 23, 24 do not form "lower composite longitudinal threads". This can be done in the Figures 10 and 10a For example, be recognized by the fact that the lower longitudinal threads each run with the involvement of four transverse threads alternately above and below the transverse threads of the lower fabric, whereas the two longitudinal threads of a functional pair - if you would consider them as a lower composite thread - jointly bind only two lower transverse threads and a Course of "under a transverse thread, over three transverse threads" have. In addition, according to the running 5-shaft binding shown each transverse thread per running side rapport ( FIG. 10 shows four repeats of the running-side binding, see below) incorporated exactly twice, wherein the connected by the functional pair 21, 22 lower transverse threads 203, 207 are already involved by the lower longitudinal threads 32, 33 twice. The lower fabric layer thus has per longitudinal thread repeat of Tissue exactly eight lower longitudinal threads. According to this embodiment, exactly four lower longitudinal threads 33, 34, 35, 36 are arranged between the two functional pairs 21, 22 and 23, 24.

Of the twenty transverse threads, twelve transverse threads 101 to 112 are assigned to the upper fabric layer and eight transverse threads 201 to 208 to the lower fabric layer. The twelve transverse threads 101 to 112 of the upper layer have a smaller diameter than the eight transverse threads 201 to 208 of the lower layer. The twelve transverse threads 101 to 112 are formed as upper transverse threads and extend exclusively in the upper fabric layer, and the eight transverse threads 201 to 208 are formed as lower transverse threads, which extend exclusively in the lower fabric layer. That is, none of the transverse threads 101 to 112 change to the running side and the lower fabric layer, respectively, and none of the transverse threads 201 to 208 change to the paper side and the upper fabric layer, respectively. It is noted, however, that the invention is not limited to the number of upper and lower transverse threads shown nor to the ratio of upper transverse threads to lower transverse threads shown (here 12: 8 or 3: 2). Also, the diameter of the upper transverse threads may be e.g. equal to or greater than the diameter of the lower transverse threads.

As in FIG. 9 4, the four upper longitudinal threads 11-14 and the two upper composite longitudinal threads formed by the two functional pairs 21, 22 and 23, 24 together with the twelve upper transverse threads 101-112 form a paper-side plain weave. Thus, the upper longitudinal thread 11 runs alternately above and below an upper transverse thread 101-112 (sequence / sequence = once over, once under). The course of the upper composite longitudinal thread 21, 22 is opposite the course of the upper longitudinal thread 11 offset by exactly one upper transverse thread. The upper longitudinal thread 12 and the upper composite longitudinal thread 23, 24 have the same course as the upper longitudinal thread 11, and the course of the upper longitudinal threads 13 and 14 corresponds to the course of the upper composite longitudinal thread 21, 22. Thus, binds each of the upper longitudinal thread and upper composite longitudinal thread each second upper transverse thread into the tissue. Although this bond has been found to be suitable for the topsheet or the paper side, the invention is not limited to a paper-side plain weave.

How out FIG. 10 As can be seen, form the eight lower longitudinal threads 31-38 together with the eight lower transverse threads 201-208 a running side 4-shaft binding. However, the embodiment / design of the lower fabric shown is only one of several possible embodiments, ie, other side bonds may be provided, although the binding shown has been found to be suitable. Each of the eight lower longitudinal threads 31-38 runs alternately above and below a lower transverse thread and thereby binds exactly four lower transverse threads. Thus, for example, the lower longitudinal thread 31 binds the lower transverse threads 202, 204, 206 and 208, and the lower longitudinal thread 32 binds the lower transverse threads 201, 203, 205 and 207, ie the course of the longitudinal thread 32 disposed adjacent to the longitudinal thread 31 offset by a transverse thread. The course of the longitudinal thread 33 arranged adjacent to the longitudinal thread 32 corresponds to the course of the longitudinal thread 32, and the course of the longitudinal thread 34 arranged adjacent to the longitudinal thread 33 corresponds to the course of the longitudinal thread 31. The thread formed by the lower longitudinal threads 31, 32, 33 and 34 4-shaft binding is by the lower longitudinal threads 35, 36, 37 and 38th repeated. In addition, the running side 4-shaft binding is repeated after four lower transverse threads. In other words, in the Figures 10 and 10a Four reports of the 4-shaft running side binding shown. Each running cross weave repeat binds each lower cross thread twice.

According to the in the Figures 9-11 As shown, only the binding of the upper fabric layer is completed by the longitudinal threads of the two functional pairs 21, 22 and 23, 24. The binding of the lower fabric layer is formed solely by the eight lower longitudinal threads (together with the transverse threads running in the lower fabric). In the lower fabric, the longitudinal threads of the two functional pairs 21, 22 and 23, 24 are used as separate binding threads, which connect an already fully formed fabric to the upper fabric.

Put the in FIG. 9 shown upper fabric layer on the in FIG. 10 shown lower fabric layer (corresponding to FIG. 7 the first embodiment), so in the plan view of the fabric is always an upper longitudinal thread between two lower longitudinal threads arranged. Thus, the upper longitudinal thread 11 is in the plan view substantially between the two lower longitudinal threads 31, 32 (see. FIG. 11 ), the upper longitudinal thread 12 lies substantially between the lower longitudinal threads 33, 34, the upper longitudinal thread 13 is substantially between the lower longitudinal threads 35, 36, and the upper longitudinal thread 14 is substantially between the lower longitudinal threads 37, 38. This results a ratio of upper to lower longitudinal threads of 4: 8 or 1: 2. If the two upper composite longitudinal threads formed by the four longitudinal threads 21, 22, 23, 24 are also assigned to the upper fabric layer, the result is a longitudinal thread ratio of 6: 8 or 3: 4 (if none of the four Longitudinal threads 21, 22, 23, 24, which according to this embodiment have no fabric function in the lower fabric layer but merely function as separate fabric threads associated with the lower fabric layer). If the four longitudinal threads 21, 22, 23, 24 are evenly distributed on the upper fabric and the lower fabric, a ratio of 6:10 or 3: 5 is obtained as for the first embodiment. The described longitudinal thread ratio of 6: 8 (or 6:10) and the associated reduced number of longitudinal threads on the paper side favors the formation of transverse stitches (see FIG. 9 ), which allow a suitable fiber support. The comparatively large number of lower longitudinal yarns compensates for the reduction in strength and the increase in machine direction strains associated with the formation of the transverse meshes.

As with the fabric according to the first embodiment, in the fabric according to the second embodiment, the diameter of the upper longitudinal threads 11-14 may be equal to the diameter of the threads 21-24 of the functional pair. As a result, a uniform paper page can be obtained, which is slightly disturbed only by the four change points A1, A2, B1 and B2. Furthermore, the upper longitudinal threads 11-14 and the threads 21-24 of the functional pairs can be easily arranged on a common warp beam (eg warp beam X2 in FIG FIG. 8 ).

The diameter of the lower longitudinal threads 31-38 may be the same as the diameter of the upper longitudinal threads 11-14 and the threads 21-24 of the functional pairs, as in the fabric according to the first embodiment. However, it is also possible to use for the lower longitudinal threads of threads with a larger diameter, since the lower longitudinal threads on a separate Warp beam can be applied (eg warp beam X1 in FIG. 8 ) and the run-side binding is formed exclusively by the lower longitudinal threads. If the lower longitudinal threads have a larger diameter than the longitudinal threads of the functional pairs, the lower longitudinal threads protrude further from the running side than the longitudinal threads of the functional pairs running in sections in the lower fabric, so that the longitudinal threads of the functional pairs acting as separate binding threads project through the lower longitudinal threads Abrasion and wear are protected.

The fabric according to the second embodiment can be like the fabric according to the first embodiment with the in FIG. 8 produce loom or warp thread arrangement shown.

Claims (10)

1. Sheet forming screen,
   formed as a multilayer fabric having an upper fabric layer (A) comprising a first weave, and a lower fabric layer (B) comprising a second weave,
   characterized in that the multilayer fabric has a longitudinal thread repeat of sixteen longitudinal threads,
   four longitudinal threads (11, 12, 13, 14) of which are formed as upper longitudinal threads extending exclusively in the upper fabric layer and being interwoven with transverse threads (101 1 to 120, 101 to 112) extending in the upper fabric layer, thereby partially forming the first weave,
   eight longitudinal threads (31, 32, 33, 34, 35, 36, 37, 38) of which are formed as lower longitudinal threads extending exclusively in the lower fabric layer and there being interwoven with transverse threads (201 to 210, 201 to 208) extending in the lower fabric layer,
   and the remaining four longitudinal threads (21, 22, 23, 24) of which form two functional longitudinal thread pairs (21, 22; 23, 24) of two respective longitudinal threads arranged next to each other, wherein the two longitudinal threads of the respective longitudinal thread pair alternately complete the first weave, and wherein one or more or all of the four longitudinal threads forming the two functional longitudinal thread pairs extend both in the upper fabric layer and in the lower fabric layer and thereby bind the lower fabric layer to the upper fabric layer.
2. Sheet forming screen according to claim 1, wherein the eight lower longitudinal threads (31, 32, 33, 34, 35, 36, 37, 38) are interwoven with the transverse threads (201 to 210) extending in the lower fabric layer, thereby partially forming the second weave, and wherein the two longitudinal threads of the respective longitudinal thread pair (21, 22; 23, 24) alternately complete both the first weave and the second weave.
3. Sheet forming screen according to claim 1, wherein the eight lower longitudinal threads (31, 32, 33, 34, 35, 36, 37, 38) are interwoven with the transverse threads (201 to 208) extending in the lower fabric layer, thereby completely forming the second weave, and wherein the at least one longitudinal thread extending both in the upper fabric layer and in the lower fabric layer binds the lower fabric layer completely formed by the lower longitudinal threads to the upper fabric layer.
4. Sheet forming screen according to claim 3, wherein all of the four longitudinal threads forming the two functional longitudinal thread pairs extend both in the upper fabric layer and in the lower fabric layer, and wherein the two longitudinal threads of the respective functional pair alternately bind the lower fabric layer completely formed by the lower longitudinal threads to the upper fabric layer.
5. Sheet forming screen according to any of claims 1 to 4, wherein always exactly two upper longitudinal threads (12, 13) and/or exactly four lower longitudinal threads (33, 34, 35, 36) are arranged in the fabric between two functional longitudinal thread pairs (21, 22; 23, 24).
6. Sheet forming screen according to any of claims 1 to 5, wherein the upper longitudinal threads (11 to 14), the lower longitudinal threads (31 to 38) and the longitudinal threads (21 to 24) of the functional pairs have the same diameter.
7. Sheet forming screen according to any of claims 3 to 5, wherein the upper longitudinal threads (11 to 14) and the longitudinal threads (21 to 24) of the functional pairs have the same diameter, and wherein the diameter of the lower longitudinal threads (31 to 38) is greater than the diameter of the upper longitudinal threads (11 to 14) and the longitudinal threads (21 to 24) of the functional pairs.
8. Sheet forming screen according to any of the preceding claims, wherein all transverse threads extending in the upper fabric layer are formed as upper transverse threads (101 to 120, 101 to 112) extending exclusively in the upper fabric layer, and/or wherein all transverse threads extending in the lower fabric layer are formed as lower transverse threads (201 to 210, 201 to 208) extending exclusively in the lower fabric layer.
9. Sheet forming screen according to any of the preceding claims, wherein the ratio of transverse threads extending in the upper fabric layer to transverse threads extending in the lower fabric layer is greater than 1, for example at least or exactly 2:1 or for example at least or exactly 3:2.
10. Sheet forming screen according to any of the preceding claims, wherein the first weave is a plain weave, and/or wherein the second weave is a 5-shaft weave or a 4-shaft weave.

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