WO2011147650A1

WO2011147650A1 - Fabric belt, in particular forming fabric

Info

Publication number: WO2011147650A1
Application number: PCT/EP2011/056417
Authority: WO
Inventors: Johann BÖCK
Original assignee: Voith Patent Gmbh
Priority date: 2010-05-28
Filing date: 2011-04-21
Publication date: 2011-12-01
Also published as: EP2576896A1; DE102010029447A1

Abstract

The invention relates to a fabric belt, in particular a forming fabric for a machine for producing a fibrous web, in particular a paper, cardboard or packaging paper web, comprising a running-side first fabric layer (10) and a paper-side second fabric layer (12) which is connected to the latter, wherein at least the first fabric layer (10) comprises first weft threads (B1 to B16) and first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) tied up exclusively in said first fabric layer (10), wherein the first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and the first weft threads (B1 to B16) form a running-side weave repeat (BL), wherein threads of at least one thread type of first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and first weft threads (B1 to B16) in a running-side weave repeat (BL) form two floats (F1, F2) of differing length which extend on that side of the first fabric layer (10) which faces the second fabric layer (12), wherein N is the number of threads of the other thread type of first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and first weft threads (B1 to B16), over which the longer (F1) of the floats (F1, F2) extends, and n is the number of threads of the other type of first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and first weft threads (B1 to B16), over which the shorter (F2) of the floats (F1, F2) extends. The fabric belt, in particular forming fabric, according to the invention is characterized in that it holds that: N ≥ 8 and n = N - 2.

Description

Fabric tape, in particular forming fabric

The present invention relates to a fabric tape, in particular a forming fabric for a machine for producing a fibrous web, in particular a paper, cardboard or packaging paper web, comprising a running side first fabric layer and a paper-side second fabric layer connected thereto, wherein at least the first fabric layer exclusively in this integrated first warp threads and first weft threads, wherein the first warp threads and the first weft threads form a running repeat weave, wherein threads of at least one type of yarn of first warp threads and first weft threads in a running-side weave repeat two on the second fabric layer facing side of the first fabric layer extending floats different Length, where N is the number of filaments of the other type of yarn of first warp yarns and first weft yarns over which the longer of the floats extends, and n is the number of yarns of the other type of yarns first warp yarns and first weft yarns over which the shorter of the floats extends.

Such a fabric band to be used as a forming fabric is known from the document US 5,544,678. In this known fabric tape, both the run-side first fabric layer and a paper-side second fabric layer connected thereto by binding weft threads comprise warp or weft threads, which are each bound exclusively in these two fabric layers. The warp threads integrated in the running side first fabric layer float within a weave repeat defined by the warp and weft threads bound only in the first fabric layer of the running side first fabric layer over the weft threads of this first fabric layer in a respective weave repeat in two floating regions of different lengths. This refers to the length a respective Flottierungsbereichs on the number of wefts this run-side fabric layer over which the floating warp threads extend away. These two floats of different lengths are provided in the run-side first fabric layer on the paper-side second fabric layer side facing and should lie substantially in the same plane.

Due to the known in this known structure length of the two floats, the problem is that between the floats with the shorter length and the paper-side second fabric layer disposed above a small gap arises, while the floats with the greater length abut this second fabric layer. The intermediate space occurring in the shorter floats can locally influence the operating characteristic, in particular the dewatering property of such a fabric strip, so that corresponding irregularities in the production of a fibrous web, such as a paper, board or packaging paper web, arise or occur therein can sign off.

It is the object of the present invention to provide a fabric tape, in particular a forming fabric for a machine for producing a fibrous web, in particular a paper, board or packaging paper web, with which a better quality of the fibrous web to be produced, in particular by better drainage properties in the manufacturing process, can be achieved. According to the invention, this object is achieved by a fabric tape, in particular a forming fabric for a machine for producing a fibrous web, in particular a paper, board or packaging paper web, comprising a running side first fabric layer and a paper-side second fabric layer connected thereto, wherein at least the first fabric layer exclusively in this integrated first warp threads and first weft threads, wherein the first warp threads and the first weft threads form a running-side weave repeat, wherein threads of at least one type of yarn of first warp threads and first Weft threads in a running-side weave repeat two at the second fabric layer facing side of the first fabric layer extending floats of different lengths, where N is the number of threads of the other type of yarn of first warp yarns and first weft threads over which extends the longer of the floats, and n is the number of filaments of the other kind of first warp yarns and first weft yarns over which the shorter of the floats extends.

According to a first aspect of the invention, it is further provided that the following applies:

N> 8;

and

n = N -2.

In the case of an embodiment of the fabric tape according to the invention, it is ensured that the difference in length between the floats of different lengths within a respective weave repeat of the running side first fabric layer does not exceed a certain extent. The consequence of this is that the positioning of the two successive floats of different lengths in one and the same plane is better ensured than in the aforementioned prior art and thus the creation of gaps to the overlying second fabric layer where the shorter floats extend , is avoided.

According to a particularly advantageous embodiment, it is further proposed that the following applies:

N <12,

wherein it can preferably be provided that the following applies:

N = 8 or 10 or 12.

According to an alternatively or in combination with one or more of the preceding aspects proposed solution aspects is the beginning mentioned task in a fabric tape with generic structure solved by the following:

n> 0.75 x N. Also in this embodiment, it is ensured that the difference in the lengths of the two floats is not too large. This avoids the creation of intermediate spaces for the paper-side second fabric layer.

Preferably, it can be provided that the following applies:

n> 6.

In the case of the fabric tape according to the invention, the second fabric layer can also comprise exclusively second warp threads and second weft threads which are incorporated in the same. It should be pointed out here that the term "exclusively incorporated into this" in the context of the present invention expresses that the threads addressed in each case extend only in the respectively addressed fabric layer but do not change into another fabric layer but not that in the respective addressed fabric layer exclusively these threads, so for example, second warp threads and second weft threads, but not other threads may be present.

In order to produce a connection between the two fabric layers in a manner that is as simple as possible on the paper side in a simple manner and to minimize the overall structure of the fabric band, it is proposed that the first fabric layer and the second fabric layer be introduced into the first fabric layer in regions and partially into the second fabric layer integrated binding threads are connected to each other.

The threads of one type may be, for example, the first warp threads, in which case the threads of the other type are the first weft threads. It is further proposed that the threads of one kind are essentially in a band longitudinal direction. tion run and the threads of the other type substantially in a strip transverse direction.

The binding threads can be weft threads. It can further be provided that the binding threads are associated with each other in pairs, so that in each pair of then preferably immediately adjacent binding threads where one of the binding threads is integrated into the second fabric layer, the other runs in the first fabric layer or between the two fabric layers , and vice versa. The binding threads may extend, for example, in the band transverse direction.

The present invention will be described below in detail with reference to the accompanying drawings. It shows:

Fig. 1 is an illustration of the warp or weft paths in one

Binding repeat of a first tissue band;

2 shows an illustration of the warp or weft thread courses in one

Binding repeat of a second tissue band;

Fig. 3 viewed from the running side a representation of a running side

Binding repeat in the weave structure shown in Fig. 1; and Fig. 4 viewed from the running side, a representation of a running side

Binding repeat in the weave structure shown in Fig. 2.

Fig. 1 shows a weaving or binding structure for a fabric tape, which can be used for example as a forming fabric in a machine for producing a fibrous web, in particular a paper, cardboard or packaging paper web. In FIG. 1, the threads T1 to T16, B1 to B16 and Bi1 to Bi16 extending in the plane of the drawing are weft threads which are in a forming fabric preferably in the transverse direction of the strip, ie also in the transverse machine direction and thus also transversely to the running direction of the strip. extend. The threads which are orthogonal to the plane of the drawing and represented only by numbers 1 to 20 are warp threads which, in the example mentioned, are then in the Bandlängsrichtung and thus also extend the machine direction.

The fabric tape constructed with the structure shown in FIG. 1 has two fabric layers 10, 12. In this case, the first of the two fabric layers, ie the fabric layer 10, forms a running fabric layer, which in the representation of FIG. 1 on its underside in contact with the drive or deflection rollers, for example a machine for producing a fibrous web, in particular a paper, Cardboard or packaging paper web, occurs. The second of the fabric layers, ie the fabric layer 12, forms a paper-side fabric layer and forms in FIG. 1 at its upper side a surface for receiving the fibrous web to be produced, in particular a paper, board or packaging paper web.

Of the warp threads 1 to 20 shown in Fig. 1, the warp threads 2, 4, 7, 9, 12, 14, 17 and 19 extend exclusively in the first fabric layer 10 and are to be understood in the context of the present invention as the first warp threads. The warp threads 1, 3, 5, 6, 8, 10, 11, 13, 15, 16, 18 and 20 extend exclusively in the second, ie paper-side fabric layer 12 and are to be understood as second warp threads in the sense of the present invention. In the construction according to the invention of a fabric band, the first warp threads and the second warp threads are respectively exclusively associated with the first fabric layer 10 and the second fabric layer 12, that is, they run only in these fabric layers and do not change into the respective other of the fabric layers.

In this example shown in FIG. 1, the ratio of the second warp threads arranged in the second fabric layer 12 to the first warp threads arranged in the first fabric layer 10 is 3: 2. This ratio can also be 2: 1 or 1: 1 in other, but not explicitly illustrated embodiments.

The weft threads extending in the drawing plane of FIG. 1 comprise the weft threads B1 to B16, which are exclusively associated with the first fabric layer 10 and, in the sense of the present invention, are to be regarded as first weft threads. The weft threads T1 to T16 are exclusive to the second fabric layer 12 assigned, extend only in this second fabric layer 12 and are to be interpreted as a second weft threads in the context of the present invention.

There are still binding threads Bi 1 to Bi16. These are arranged in pairs assigned to each other directly adjacent to each other and are partially integrated into the second fabric layer 12 and partially integrated into the first fabric layer 10. In order to continue the plain weave generally existing in the second fabric layer 12 also in the binding threads or pairs of binding threads, these are where they are integrated into the second fabric layer 12, bound with plain weave, so that the two threads of a pair of binder yarn in the second fabric layer 12 itself alternating in the weft direction binding canvas and thus form a fictitious weft thread of the second fabric layer 12. FIG. 1 shows an overall binding repeat B _{G of} a fabric tape constructed according to the invention, ie the weave repeat which repeatedly repeatedly in the warp direction and weft direction repeatedly leads to an entire fabric tape. In this weave repeat B _{G of} the entire fabric tape, a running-side weave repeat B _L formed exclusively by the first warp threads and first weft threads, that is to say the threads which only extend in the first fabric layer 10, is contained. This running-side binding repeat B _L is shown in FIG. 3 viewed from the running side. The columns 2, 4, 7, 9, 12, 14, 17, 19 represent the first warp threads contained or extending in a running-side weave repeat B _{L of} the first fabric layer 10. Lines 1 to 16 represent the sixteen weft threads contained in such a running-side binding repeat B _L. In parentheses are given behind the numbers 1 to 16 respectively those numbers or numbers corresponding to the in this respect in Fig. 1 recognizable first weft threads B1 to B16.

It can be seen in FIGS. 1 and 3 that of the first warp threads 2, 4, 7, 9, 12, 14, 17, 19 within a respective running-side weave repeat B _L each of the first warp threads 2, 4, 7, 9, 12, 14, 17, 19 has two floats Fi and F ₂ . In each of these floats Fi, F _2, the first warp threads float on the side of the first fabric layer 10 facing the second fabric layer 12 over a plurality of first weft threads. In this case, the first floats Fi have a greater length than the second floats F ₂ . The floats Fi, F ₂ are separated by a respective connection point X, at which the first warp threads under a respective first weft thread set, so extend on the running side, while where they float, do not run on the running side. It should also be pointed out that the separation of the two floats Fi and F ₂ in the warp direction can also take place by means of a plurality of connection points and / or possibly a floating on the running side of the first fabric layer 10.

The floats Fi and F _{2 of} the various first warp threads present in a running-side weave repeat B _L are offset with respect to one another, so that a distribution of the connection points X between the first warp threads and the first weft threads is substantially uniform but nevertheless not regular over the surface , The length of the first floats Fi and F ₂ is chosen such that different conditions are met. In particular, the length of the second floats F ₂ , which corresponds substantially to the number n of the second weft threads covered by the second warp threads in the floatation region, is at least 75% of the length of the first floats Fi, which in turn corresponds to the number N in the region of a respective first floats Fi covered first weft threads corresponds. Thus, the second floats F ₂ compared to the first floats Fi a comparatively large extension length. It is thereby ensured that both floats Fi and F _2, in particular in relation to the second fabric layer 12 occupy a same position, ie lie in the same plane. Both floats Fi and F ₂ can thus be in contact with the second fabric layer 12 due to their extension length or the ratio of their extension lengths. The emergence of the drainage Property impairing gaps in only one type of very short floats F ₂ is thus avoided.

Furthermore, in the example shown in FIGS. 1 and 3, it can be seen that the number N, ie the first weft threads covered by a respective first floatation Fi, is 8, whereby according to a further aspect of the invention, this number N = 8 is also a minimum number Minimum length of the first floats Fi should be. The number n or the length of the second floats F ₂ satisfies the specification: n = N - 2. In the present case, this leads to a number n of 6. Also, by this relationship, if the number N is at least 8, a obtained sufficiently small difference in length between the two floats of different lengths, in which again the requirement is satisfied that n is at least 75% of N. In particular, n should not be less than 6. For the number N, the minimum value 8 has proven to be particularly advantageous. Also, a maximum value 12 has been shown to be applicable.

Another example of a fabric belt constructed with the foregoing specifications is illustrated in FIGS. 2 and 4. Again, the threads running in the planes of the drawing are weft threads, while the threads orthogonal to the plane of the drawing and represented only by numbers are warp threads. The warp threads assigned to the first, that is to say the run-side fabric layer 10 comprise the warp threads 2, 4, 6, 8, 10, 12, 14, 16. The second warp threads assigned to the second fabric layer 12 comprise the warp threads 1, 3, 5, 7, 9 , 1 1, 13, 15. Here, therefore, a ratio of the second warp threads of the second fabric layer 12 to the first warp threads of the first fabric layer 10 of 1: 1 is provided. This ratio can also be 3: 2 or 2: 1 in other, but not explicitly illustrated embodiments.

Also in this fabric structure, the first warp threads 2, 4, 6, 8, 10, 12, 14, 16 extend exclusively in the first fabric layer 10. The second warp threads 1, 3, 5, 7, 9, 11, 13, 15 extend exclusively in the second fabric layer 12th The first weft threads extending only in the first fabric layer 10, which together with the first warp threads 2, 4, 6, 8, 10, 12, 14, 16 then define the running-side weave repeat B _L shown in FIG. 4, comprise the weft threads B1 to B16. The second weft threads extending exclusively in the second fabric layer comprise the weft threads T1 to T16. These form together with the second warp threads again a plain weave on the paper side. The binding threads, which realize a mutual connection of the two fabric layers 10, 12 to each other, are again arranged in pairs adjacent to each other extending running. They include the binding threads Bi1 and Bi2, Bi3 and Bi4, Bi5 and Bi6, Bi7 and Bi8, Bi9 and Bi10, Bi1 1 and Bi12, Bi13 and Bi14, Bi15 and Bi16. As in the exemplary embodiment of FIG. 1, four of the first fabric layer 10 and the second fabric layer 12 each have exclusively associated first weft threads or second weft threads between each pair of such binder threads.

4 shows that even with this binding structure, each of the first warp threads 2, 4, 6, 8, 10, 12, 14, 16 two floats Fi, F ₂ different length, ie with different numbers N or n forms of covered first weft threads. The number N of the first floats Fi is also 8 in this example. The number n in the second floats F ₂ is again 6. Thus, the following requirements are satisfied again:

N> 8;

n = N - 2;

n> 6;

n> 0.75 X N.

Even with this fabric structure, in particular the running side first fabric layer 10, it is ensured that essentially all floats Fi and F ₂ within a respective running-side weave repeat B _L on the second fabric layer 12 facing side of the first fabric layer 10 extending in contact with the first tissue layer come. The emergence of local gaps especially where the shorter second floats F ₂ themselves extend is avoided.

It should finally be pointed out that the principles of the present invention emerge particularly advantageously when the in a respective running-side binding repeat, which with respect to the number Z _{K of} the first warp threads and Z _{s of} the first weft threads of the specification: Z _s = 2 x Z _K suffice, occurring floats of different lengths are formed by the warp threads or in the machine direction and thus strip longitudinal direction extending threads. It should nevertheless be pointed out that those threads of first warp threads and first weft threads, which form these floats, could in principle also be the first weft threads. Also, those filaments forming these floats could extend in the cross-machine direction.

It should also be pointed out that the plain weave formed on the paper side with the first warp threads and first weft threads provided there, or also the binding threads or pairs of binder threads, does not necessarily have to be provided. Although this is basically advantageous for generating the lowest possible marking effects. Other bindings are also possible here in principle. Furthermore, it should be noted that in particular the binding threads can take other courses. In particular, these could have a larger number of crossing points within a respective binding repeat B _G. The crossing points between the individual binding threads of the binding thread pairs could be distributed differently and ultimately the binding threads could also be provided by warp threads or respective pairs of warp threads.

Claims

Fabric tape, in particular Formiersieb claims

Fabric tape, in particular forming fabric for a machine for producing a fibrous web, in particular a paper, board or packaging paper web, comprising a running side first fabric layer (10) and a paper-side second fabric layer (12) connected thereto, wherein at least the first fabric layer (10) exclusively in this involved first warp threads (2, 4, 7, 9, 12, 14, 17, 19, 2, 4, 6, 8, 10, 12, 14, 16) and first weft threads (B1 to B16), wherein the first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and the first weft threads (B1 to B16) have a running-side weave repeat (B _L ), wherein threads of at least one kind of yarn of first warp threads (2, 4, 7, 9, 12, 14, 17, 19, 2, 4, 6, 8, 10, 12, 14, 16) and first weft threads (B1 to B16) in a running-side binding repeat (B _L ) two on the second fabric layer (12) facing side of the first fabric layer (10) extending floats (Fi, F ₂ ) of different lengths where N is the number of threads of the other thread type of first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and first weft threads (B1 to B16) over which the longer (Fi) of the floats (Fi, F ₂ ) extends, and n is the number of threads the other kind of first warp yarns (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and first weft yarns (B1 to B16) is over which extends the shorter (F ₂ ) of the floats (Fi, F ₂ ),

characterized,

that applies:

N> 8;

and Fabric tape according to claim 1,

characterized,

that applies:

N <12.

Fabric tape according to claim 1 or 2,

characterized,

that applies:

N = 8 or 10 or 12.

Fabric tape according to one of claims 1 to 3 or the preamble of claim 1,

characterized,

that applies:

n> 0.75 x N.

Fabric tape according to claim 4,

characterized,

that applies:

n> 6.

Fabric tape according to one of claims 1 to 5,

characterized,

in that the second fabric layer (12) exclusively has second warp threads (1, 3, 5, 8, 10, 11, 13, 15, 16, 18, 20, 1, 3, 5, 7, 9, 1 1, 13, 15) and second weft threads (T1 to T16).

Fabric tape according to one of claims 1 to 6,

characterized,

that the first fabric layer (10) and the second fabric layer (12) by partially in the first fabric layer (10) and partially in the second Fabric layer (12) integrated binding threads (Bi 1 to Bi 16) are interconnected.

8. fabric tape according to one of claims 1 to 7,

characterized,

that the threads of one type are the first warp threads (2, 4, 7, 9, 12, 14, 17, 19; 2, 4, 6, 8, 10, 12, 14, 16) and the threads of the other type are the first Weft threads (B1 to B16) are.

9. fabric tape according to one of claims 1 to 8,

characterized,

in that the threads of one type run essentially in one band longitudinal direction and the threads of the other type run essentially in a band transverse direction.

10. A fabric tape according to claim 4 or any one of claims 5 to 9, if dependent on claim 4,

characterized,

that the binding threads (Bi 1 to Bi 16) are weft threads or / and are associated with each other in pairs.

1 1. Fabric tape according to claim 4 or any one of claims 5 to 10, when dependent on claim 4,

characterized,

in that the binding threads (Bi 1 to Bi 16) extend essentially in a band transverse direction.