CN102041707B

CN102041707B - Woven paper maker fabric

Info

Publication number: CN102041707B
Application number: CN201010528228.XA
Authority: CN
Inventors: 雷克斯·巴雷特
Original assignee: Heimbach GmbH and Co KG
Current assignee: Heimbach GmbH and Co KG
Priority date: 2009-10-23
Filing date: 2010-10-21
Publication date: 2014-04-16
Anticipated expiration: 2030-10-21
Also published as: EP2314762B1; BRPI1004135A2; JP2011089247A; KR20110044704A; CN102041707A; JP5192021B2; KR101265663B1; ES2392127T3; PT2314762E; EP2314762A1

Abstract

The present invention relates to a woven paper maker fabric. Concretely, provided is a paper maker fabric (1, 21, 31, 41) having a first fabric layer (2) made of first threads (4, 5, 6) and a second fabric layer (3) made of second threads being connected by first binder threads (6) extending in one direction being divided into first basic threads (5) forming a plain weave with the first threads (4), and into the first binder threads (6) forming a plain weave with the first threads (4) section-wise, the first binder threads (6) bind one second thread (9) at binder points (7, 8) on the outside, wherein first threads (4) extending transversely to the first binder threads (6) are not bound at the binding points (7, 8), the number of which exceeds the number of the second threads being bound there by the number of at least two, wherein only one single binder thread (6) is provided between two adjacent first basic threads (5) respectively.

Description

Woven papermaker's fabric

Technical Field

The invention relates to a woven papermaker's fabric, in particular a forming fabric, having a first woven fabric layer arranged for the paper side and a second woven fabric layer made of first threads interwoven with one another, which form a recurring circulation of the first woven fabric, which is arranged for the machine side, the second woven fabric layer being made of second threads interwoven with one another, which form a recurring circulation of the second woven fabric, the first woven fabric layer and the second woven fabric layer being connected to one another by first binding threads formed by first threads, the first threads extending in one direction being divided into first base threads and first binding threads, the first base threads forming a plain weave with the first threads extending transversely to the first base threads, the first binding threads forming a plain weave with the first threads extending transversely to the first binding threads in the cross-sectional direction, the first binding thread binds only a single second thread running transversely to the first binding thread at a binding point on the outside, thus changing from a first woven fabric layer to a second woven fabric layer and back again, wherein three first threads running transversely to the first binding thread are not bound by the first binding thread at the binding point, respectively.

Background

Woven papermaking fabrics are intended to be used in components of papermaking machines as supports for paper webs. They are endless woven fabrics or endless fabrics made by sewing, which fabrics circulate in the papermaking machine. In the first part of the paper machine, a forming fabric is used on the top layer, the pulp is placed at the beginning of said top layer and the pulp is dewatered by the forming fabric to form a paper web.

Woven papermaker's fabrics are known as forming fabrics, which have two separate woven fabric layers disposed on top of each other: a first woven fabric layer, or a woven fabric layer on the paper side, formed of first longitudinal threads and first transverse threads; and a second woven fabric layer, or woven fabric layer on the machine side, formed from second longitudinal threads and second transverse threads. In the two woven fabric layers, the first and second threads form recurring loops of the first and second woven fabrics. Examples of these types of woven papermaking fabrics particularly suitable for use in the web forming section of a papermaking machine are available from WO 2005/014926a1, WO 2005/017254a1, WO 2006/083604a1, EP 0794283 a1, EP 1693506B 1, EP 1586696B 1, EP 0998607B 1, US 5826627A, EP 1936024 a1 and EP 1506339B 1.

The connection between the two woven fabric layers is achieved by means of a binding cross thread which forms part of the respective first thread loop, i.e. unlike separate binding threads as disclosed in DE 3305713C 1 which form a structural thread or an inner thread. The strapping of the separated strapping line in line with the circulation of the first longitudinal line is interrupted only at the strapping points. Here, the binding transverse wires are bound between two first longitudinal wires, the binding transverse wires are bound to the first longitudinal wires on the outer side (paper side), and the binding transverse wires are not bound to another first longitudinal wire and second longitudinal wire on the outer side between the first longitudinal wires. For this purpose, the binding of the transverse threads is changed from the first woven thread layer to the second woven thread layer, the second longitudinal threads are bound and returned again to the first woven thread layer.

With a papermaker's woven fabric of the aforementioned type, the binding transverse threads are woven in pairs, respectively, i.e. the two binding transverse threads are always arranged between two first base threads, respectively, which are not binding threads and which are regularly bound with the first longitudinal threads in a plain weave.

In the embodiment disclosed in EP 1506339B 1, the first binding thread is also bound with the first longitudinal thread in a plain weave, however interrupted at the binding point. An additional alternative weft thread is provided between a pair of adjacent binding threads to complete the two thread paths formed by the two adjacent binding cross threads.

Known papermaker's woven fabrics form rectangular or square regular drainage openings. However, the woven structure produces a disrupted plain weave structure. This impairs the quality of the sheet and creates marks in the web.

Disclosure of Invention

The aim forming the basis of the present invention is to devise a woven papermaking fabric, which is used in particular in the web-forming section of a papermaking machine, so that the drainage properties are improved and thereby the risk of forming marks in the paper web is reduced.

This object is achieved according to the invention in that only one single first lashing wire is arranged between two adjacent first base lines, respectively. In particular, the first binder thread is arranged directly adjacent to two adjacent first baselines, such that no further thread is present between the two adjacent baselines other than the first binder thread.

The basic idea of the invention is to reduce the number of lashing wires between two adjacent baselines to one single lashing wire. This results in a design with irregularly shaped drainage openings on the paper side, even though they are evenly distributed. The drain opening formed between two adjacent first wires, i.e., between the first base string and the first binding wire, is in the shape of a lens having one flat surface and one concave surface. The elongated orientation of the drain opening provides good fiber support, particularly when the first binder wire and base string extend in a cross-machine, i.e., transverse, direction. This particular drainage surface pattern gives the sheet a drainage structure that is significantly different from that produced with a regular square drainage surface pattern.

In an embodiment of the present invention, there is provided: the first binding thread extends as a first binding transverse thread transversely to the provided running direction of the woven papermaker's fabric and only a single second longitudinal thread is bound at the binding point. This embodiment gives good fiber support, which is particularly important if the papermaking fabric is designed as a forming fabric. However, it may alternatively be provided that: the first binding thread extends as a first binding longitudinal thread in the provided travel direction of the woven papermaker's fabric and only a single second transverse thread is bound at the binding point.

In a further embodiment, at the bundling point, the second wire bundled by the first bundling wire and the first wire parallel to said second wire respectively form a pair of wires lying on top of each other, and the first wire of these pairs is bundled by the first base wire adjacent to the first bundling wire in the same way as the second wire is bundled by the adjacent first bundling wire. Furthermore, it is advantageous if the first bundle of wires is separated from each adjacent first bundle of wires by only one first base string extending parallel to the adjacent first bundle of wires, since then two adjacent base strings are apparently close to each other at the bundling point of the first bundle of wires extending between the two base strings, thereby forming the drain opening having the shape of a lens. However, the number of first baselines between two adjacent first binder wires can be more than one, for example two, three or at most four.

In another embodiment of the invention, at least one pair of first and second threads lying on top of each other respectively extends at a tying point adjacent to the second thread or threads tied by the respective first tying thread, and a particular first tying thread passes between the two threads of the first and second threads when changing the woven fabric layer.

In order to reduce the number of binding points, it can be provided that: the first wires flow under the lower side of the first wires running transversely to the first wires, between two adjacent binding points in the extension of the first wires and symmetrically to the binding points, respectively, the number of these first wires corresponding to the number of first wires running parallel at the binding points which are not bound by the respective first wires.

The basic idea behind the present invention is suitable for a woven papermaker's fabric, with which first threads extending transversely to the first binder threads are present in a number of threads that is at least as large as the number of second threads extending parallel to the first binder threads, i.e. the ratio of the number of threads of these first threads to the number of second threads is 1: 1. However, ratios of 2: 1, 3: 2, 1: 2 or 2: 3 can also be considered without any limitations associated therewith. Furthermore, the ratio of the number of first binders and first baselines extending parallel to the first binders to the number of second lines extending parallel to the first baselines should be equal to 1: 1, 2: 1 or 3: 2.

The invention does not exclude that in addition to the first lashing wire also a second lashing wire formed by a second wire is present. These second lashing wires advantageously extend transversely to the first lashing wires and are lashed at a lashing point with at least one first wire extending transversely to the second lashing wires.

Woven papermaking fabrics of the present type, i.e. fabrics connected to a woven fabric layer by structural or intrinsic tying threads, are particularly suitable for woven fabrics in which the second woven layer is woven in at least four axes or bundles and up to 24 axes, in particular six or eight axes.

All synthetic materials are suitable as raw materials for the threads, which synthetic materials are usually used together with woven papermaking fabrics, and especially forming fabrics. Advantageously, the threads extending in the direction of travel provided by the woven papermaker's fabric are made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or a mixture or copolymer of these materials. The threads running transversely to the provided running direction should be made of PET, Polyamide (PA) or a mixture or copolymer of these raw materials or a blend of these raw materials with Polyurethane (PU).

As regards the cross-sectional shape of the wire, all known cross-sectional shapes are possible, in particular circular, oval, rectangular cross-sections or those with other profiles. Furthermore, a thread can be provided which is twisted or braided from at least two monofilaments or multifilaments. Finally, it is possible to use a coating provided in particular made of urethane, acrylic or using nanoparticles.

Drawings

In the drawings, the invention is shown by way of example embodiments. These figures are shown below:

FIG. 1 is a cross-section through a first woven papermaker's fabric;

FIG. 2 is a top plan view of the paper side of the papermaker's fabric illustrated in FIG. 1;

FIG. 3 is a cross-section through a second woven papermaker's fabric;

FIG. 4 is a cross-section through a third woven papermaker's fabric; and

figure 5 is a cross-section through a fourth woven papermaker's fabric.

Detailed Description

The woven papermaker's fabric 1 shown in figure 1 has: the paper side and hence the first woven fabric layer 2; and the machine side and thus the second woven fabric layer 3. The two

woven fabric layers

2, 3 are placed on top of each other.

The first woven fabric layer 2 consists of a first longitudinal thread extending in the direction of travel of the papermaker's woven fabric 1 (identified for example by 4) and a first transverse thread extending transversely thereto, both threads having a circular cross section. The first transverse wire is composed of a first transverse baseline 5 and a first transverse lashing wire 6. The two

threads

5, 6 alternate with each other in the direction of the first longitudinal thread 4. The first transverse basic string 5 is interwoven with the first longitudinal string 4 in a plain weave, whereas the first bundled transverse string is bundled with the first longitudinal string 4 in a plain weave only in the cross-sectional direction between two adjacent bundling points 7, 8 (i.e. above one first longitudinal string 4, below an adjacent first longitudinal string 4 and above the next first longitudinal string 4).

The second woven fabric layer 3 is formed by second longitudinal threads extending in the direction of travel (identified for example by 9) and by second transverse threads 10, of which only a single second transverse thread 10 is shown here. The second transverse wires 10 flow outside (i.e. on the machine side), respectively, under the five second longitudinal wires 9, and then bind one second longitudinal wire 9 in each node 11. This is referred to as a weft sliver due to the long floating section of the second transverse thread 10. The second longitudinal threads 9 as well as the second transverse threads 10 also have a circular cross section.

The ratio of the number of threads between the first and second longitudinal threads 4, 9 is 1: 1, i.e. only a single first longitudinal thread 4 extends over each single second longitudinal thread 9, forming a pair of first and second longitudinal threads 4, 9 one above the other.

The first transverse lashing wire 6 ties the second longitudinal wire 9 at the lashing points 7, 8 at specific regular intervals in the outer (i.e. machine side)

nodes

12, 13, thereby connecting the two

woven fabric layers

2, 3. At each

binding point

7, 8 the respective first transverse binding wire 6 passes between a pair 14 of first and second longitudinal wires 4, 9 located above each other and is then bound to the next second longitudinal wire 9 on the outside, i.e. the machine side. The first transverse lashing wire 6 then passes again between the pair 15 of first and second longitudinal wires 4, 9 which are located above each other, and is then strapped to the next first longitudinal wire 4 on the outer side, i.e. the paper side, and runs in plain weave. At the next strapping point 8, the first transverse strapping line 6 extends in the same manner. At each

binding point

7, 8, three adjacent first longitudinal wires 4 are not bound by the first transverse binding wires 6, but only by two adjacent first transverse base wires 5. Thanks to this mode, the first longitudinal wire 4, which is located above the second longitudinal wire 9, which is tied up by the first transverse tying wire 6, is tied up by two first transverse base wires 5, said first transverse base wires 5 extending below the lower side of the first longitudinal wire 4 adjacent to the first transverse tying wire 6.

Fig. 2 shows the extension of the first longitudinal line 4 (coloured black), the first transverse base line 5 (coloured dark grey) and the first transverse lashing line 6 (coloured light grey). Can be identified as follows: the first transverse lashing wire 6 extends substantially straight, whereas the first transverse baseline 5 has a wave-like extension. At the

binding points

7, 8, for example at the binding point 7, the first transverse binding wires 6 are changed to the second woven fabric layer 3 (not shown in the figure) such that the first longitudinal wires 4 extending above the first transverse base wires 5 force the adjacent two first transverse base wires 5 to approach each other and thus partially cover the first binding wires 6. The displacement of the first transverse baseline 5 results in a drain opening (identified e.g. by 16, 17) having a lens shape with one flat surface formed by the next first transverse tying wire 6 and a concave surface formed by the adjacent first transverse baseline 5. These

drainage openings

16, 17 are regularly distributed near the paper side of the first woven fabric layer 2, providing good fiber support due to their elongated orientation transverse to the direction of travel.

The woven papermaker's fabric 21 shown in figure 3 differs only a little from the papermaker's fabric 1 according to figure 1 and this is why the same reference numerals are used for the same parts. The only difference is that the binding points 8 of the woven papermaker's fabric 1 are omitted, so that the distance between the two binding points 7 is doubled. Instead of the lashing points 8, the first transverse lashing wire 6 runs under three consecutive first longitudinal wires 4. The improvement of the embodiment shown in fig. 3 will not be interrupted if the aforementioned floating is replaced by a continuation of the plain weave, so that the binding in the plain weave extends between two binding points 7.

The woven papermaker's fabric 31 shown in figure 4 also differs only slightly from the woven papermaker's fabric 1 according to figure 1, so the reference numerals seen in figure 1 are also used this time for the same parts and, as regards these parts, reference is made to the description of the woven papermaker's fabric 1 according to figure 1. The only difference is the ratio of the number of threads between the first and second longitudinal threads 4, 9. Here, the ratio is 1: 2, the arrangement of the first and second longitudinal threads 4, 9 being such that pairs 14, 15 of first and second longitudinal threads 4, 9 lying on top of each other are formed only above every second longitudinal thread 9. Due to this design, the paper side of the first woven fabric layer 2 is more open and the drain opening is more elongated than the

drain openings

16, 17 shown in fig. 2. As in the embodiments shown in fig. 1-3, the tie points 7, 8 may be replaced with respect to the

nodes

12, 13 of the second transverse line 10.

The woven papermaker's fabric shown in figure 5 differs from the woven papermaker's fabric 1 according to figure 1 only with respect to the ratio of the number of first longitudinal threads 4 to second longitudinal threads 9. This is why the same reference numerals are used here for the same parts. The ratio here is 3: 2, i.e. each third second longitudinal thread 9 is omitted and the floating portion of the second transverse thread 10 extends below five second longitudinal threads 9, the distance of said five second longitudinal threads 9 being greater, so that two

binding points

7, 8 are created within the floating segment of the second transverse thread 10, i.e. between two adjacent nodes 11.

Claims

1. A woven papermaker's fabric (1, 21, 31, 41) having a first woven fabric layer (2) and a second woven fabric layer (3), the first woven fabric layer (2) being arranged for the paper side, the first woven fabric layer (2) being made of first threads (4, 5, 6) interwoven with each other, the first threads (4, 5, 6) forming a recurring circulation of the first woven fabric, the second woven fabric layer (3) being arranged for the machine side, the second woven fabric layer (3) being made of second threads interwoven with each other, the second threads forming a recurring circulation of the second woven fabric,

the first woven fabric layer (2) and the second woven fabric layer (3) are connected to each other by a first binder thread (6) formed by the first thread,

said first thread extending in one direction being divided into a first base thread (5) and said first binding thread (6), said first base thread (5) forming a plain weave with another first thread (4) extending transversely to said first base thread (5), said first binding thread (6) forming a plain weave in a cross-sectional direction with said another first thread (4) extending transversely to said first binding thread (6),

the first binding thread (6) binds only a single second thread (9) extending transversely to the first binding thread (6) at binding points (7, 8) on the outside, in such a way that a change is made from the first woven fabric layer (2) to the second woven fabric layer (3) and back again,

wherein at the binding points (7, 8) three of the above-mentioned further first threads (4) extending transversely to the first binding thread (6) are not bound by the first binding thread (6) respectively,

characterized in that only one single first binding wire (6) is arranged between two adjacent first base wires (5), respectively.

2. A woven papermakers' fabric as claimed in claim 1, wherein said first binder thread (6) is arranged directly adjacent two adjacent said first elementary threads (5), one on each side, respectively.

3. A woven papermakers 'fabric according to claim 1 or 2, characterized in that the first binder thread (6) extends as a first binder transverse thread transversely to the direction of travel of the woven papermakers' fabric (1, 21, 31, 41) provided and that only a single longitudinal second thread (9) is bound at the binding point (7, 8),

or,

the first binding thread extends as a first binding longitudinal thread in the travel direction of the woven papermaker's fabric provided and binds only a single transverse second thread at the binding point.

4. A woven papermakers' fabric according to claim 1 or 2, characterized in that at said tying points (7, 8), said second threads (9) tied by said first tying thread (6) and said further first threads (4) parallel to said second threads (9) respectively form a pair of threads superposed on each other, such that said further first threads (4) of a pair of threads are tied by said first base thread (5) adjacent to said first tying thread (6) in the same way as said first tying thread (6) ties said second threads (9).

5. A woven papermakers' fabric as claimed in claim 1 or 2, wherein said first binder thread (6) is separated from the respective adjacent first binder thread (6) by a single first elementary thread (5) extending parallel to said first binder thread (6), or wherein the number of first elementary threads (5) is at most four.

6. A woven papermakers' fabric according to claim 1 or 2, characterized in that at least one pair (14, 15) of another first (4) and second (9) thread on top of each other extends at said tying point (7, 8), respectively, which tying point (7, 8) is adjacent to said second thread (9) tied by the respective first tying thread (6), and,

the first binding thread (6) passes between the further first thread (4) and the second thread (9) while passing between the first woven fabric layer (2) and the second woven fabric layer (3).

7. A woven papermaking fabric according to claim 1 or 2, characterised in that the ratio of the number of said further first threads (4) extending transversely to said first binder threads (6) to the number of said second threads (9) extending parallel to the latter is equal to 1: 1. 2: 1. 3: 2. 1: 2 or 2: 3.

8. a woven papermaking fabric according to claim 1 or 2, characterised in that the ratio of the number of first binder threads (6) and first base threads (5) extending parallel to the first binder threads (6) to the number of second threads extending parallel to the first base threads (5) is equal to 1: 1. 2: 1 or 3: 2.

9. a woven papermaking fabric according to claim 1 or 2, characterised in that in addition to the first strapping line there is provided a second strapping line formed by the second line, which second strapping line extends transversely to the first strapping line and is strapped at the strapping point with at least one first line extending transversely to the second strapping line.

10. A woven papermaking fabric according to claim 1 or 2, characterised in that the second woven layer (3) is woven in at least four and at most 24 axes.

11. A woven papermakers 'fabric as claimed in claim 1 or 2, characterised in that the threads (4, 9) extending in the direction of travel provided for the woven papermakers' fabric are made of PET, PEN or of a mixture or copolymer of these materials, and/or the threads (5, 6, 10) extending transversely to the direction of travel provided are made of PET, PA or a mixture or copolymer of these materials, or a blend of these materials with PU.

12. A woven papermakers' fabric as claimed in claim 1 or 2, characterized in that said threads (4, 5, 6, 9, 11) have a circular, elliptical, oblong cross-section or a cross-section with a different profile.

13. A woven papermakers' fabric as claimed in claim 1 or 2, characterized in that threads (4, 5, 6, 9, 11) are provided, that the threads (4, 5, 6, 9, 11) are twisted or braided from at least two monofilaments or multifilaments, and/or that the threads (4, 5, 6, 9, 11) are provided with a coating.

14. A woven papermaking fabric according to claim 1 or 2, characterised in that the number of first baselines (5) extending in parallel between two adjacent first binder threads (6) is at most four.

15. A woven papermakers' fabric as claimed in claim 10, wherein said second woven layer (3) is woven six-or eight-fold.

16. A woven papermakers fabric as claimed in claim 13, wherein the coating is made of urethane or acrylic or using nanoparticles.