JP2008509293A - Three-layer fabric of warp runners with a pair of intrinsic warp binders - Google Patents

Abstract

  Disclosed is a paper machine fabric that can be used in a paper machine. Paper machine fabric is a paired machine direction (MD) interlaced with a first system of weft yarns (1, 3, 4, 6, 7, 9, 10,...) Across the machine. MD warp yarns interwoven with a first layer of warp yarns (W11, W12) and a second system of CD weft yarns (2, 5, 8,...) And a second layer formed by the second system of W1, W2). The paired MD yarns are interwoven with a second system of CD weft yarns that are intrinsic to the first layer and bond the second layer to the first layer. The second system of MD warp yarns forms a long float or warp runner on the outer surface of the second layer. In this manner, triple layered fabrics having a pair of intrinsic binder and warp runners can be made to improve wear resistance on the wear side.

Description

  The present invention relates to a papermaking technique. In particular, the present invention relates to a forming fabric for a forming portion of a paper machine.

  During the papermaking process, a fiber web made of cellulose is formed by depositing a fiber slurry, ie an aqueous suspension of cellulose fibers, on a forming fabric that moves in a forming section of a paper machine. A large amount of water is discharged from the slurry through the forming cloth, and a fiber web made of cellulose remains on the surface of the forming cloth.

  The newly formed cellulose fiber web proceeds from the forming section to a pressing section that includes a series of press nips. Cellulose fiber webs pass through a press fabric, or a press nip often supported by two such press fabrics. In the press nip, a compressive force is applied to the cellulose fiber web. With this force, water is squeezed out, and the cellulose fibers in the web adhere to form a paper sheet from the cellulose fiber web. This water is received by the press fabric or various fabrics and ideally does not return to the paper sheet.

  The paper sheet eventually proceeds to a drying section having at least a series of rotatable drying drums or cylinders heated internally with steam. The newly formed paper sheet is directed by a dry cloth to a serpentine path arranged continuously around each of the series of drums, where the paper sheet is in close proximity to the surface of the drum Hold. The heated drum reduces the moisture content of the paper sheet to the desired level by evaporation.

  As should be understood, the forming fabric, the press fabric and the drying fabric all take an endless form on the paper machine and function in the manner of a conveyor. It should also be understood that paper manufacture is a continuous process that proceeds at a significant rate. That is, the fiber slurry is continuously deposited on the forming cloth of the forming unit, while the newly manufactured paper sheet is wound on the roll after escape from the drying unit.

  The press fabric is also involved in the final finishing of the surface of the paper sheet. That is, the press fabric is designed to have a smooth surface and a uniform elastic structure so as to complement the smooth, markless surface of the paper during passage through the press nip.

  The press fabric receives a large amount of water extracted from the paper that wets in the press nip. In order to fulfill this function, there must literally have a space commonly referred to as so-called void capacity inside the press fabric for the water to move, and this fabric is resistant to water throughout its service life. It must have sufficient permeability. Finally, the press fabric must be able to prevent water received from the wetting paper from returning to the paper after exiting the press nip and rewetting the paper.

  Woven fabrics take many different forms. For example, an endless form woven or an endless form having a seam after plain weaving.

  The present invention particularly relates to a forming cloth used in a forming portion. The forming fabric plays an important role during the papermaking process. One of the functions is a function of forming a paper product and transporting the manufactured paper product to the press section as described above.

  However, the forming fabric also needs to solve the problems of water removal and sheet formation. That is, the forming fabric is designed to allow the passage of water (that is, to control the discharge rate) while at the same time need to block the passage of fibers and other solids with the passage of water. is there. When discharge occurs extremely early or late, paper quality and machine efficiency are affected. In order to control discharge, the space within the forming fabric that discharges water, commonly referred to as void volume, must be designed appropriately.

  Modern forming fabrics are manufactured in a variety of forms designed to meet the requirements of the paper machine introduced to suit the grade of paper being manufactured. Generally, the forming fabric has a base fabric woven with monofilaments, and may be a single layer or multiple layers. The yarn is typically molded from any of a variety of synthetic polymer resins used for this purpose by those skilled in the paper machine fabric art, such as polyamide and polyester resins.

  The design of the forming fabric requires a compromise between the desired fiber support and fiber stability. A fine mesh fabric may provide the desired paper surface properties, but such a design may lack the desired stability, resulting in a shortened fabric life. Conversely, a coarse mesh fabric provides stability and long life at the cost of paper support. Multilayer fabrics have been developed to minimize this design trade-off relationship and optimize both support and stability. For example, in double and triple layer fabrics, along with drainage, the forming side is designed for support, while the wear side is designed for stability.

  The triple layer design also allows the fabric forming surface to be woven independently of the wear surface. Because of this independence, the triple layer design can provide a high level of fiber support and optimal internal void volume. Thus, the triple layer is significantly improved in terms of emissions over single layer and double layer designs.

  In essence, a triple layer fabric consists of two fabrics, a forming layer and a wear layer, held together by a bond yarn. This bond is critical to the overall integrity of the fabric. One problem with triple layer fabrics is the relative slip between the two layers described above that causes the fabric to break over time. Bond yarns can also break the structure of the forming fabric that will result in paper marking.

  The present invention discloses a triple layered fabric having a pair of intrinsic binder and a warp runner on the wear side. The present invention provides a solution to the problem of abrasion on the machine side of the fabric and provides good fiber support with a relatively low caliper and adequate void volume.

  Accordingly, the present invention relates to a forming fabric used in a forming section of a paper machine, but the present invention can also be applied to a press section and / or a drying section of a paper machine.

  The fabric according to the invention comprises a first layer formed of a first system of machine direction (MD) warp yarns interlaced with a first system of machine direction (CD) weft yarns across the machine; A triple layer forming fabric having a second system of MD warp yarns interwoven with a second system of CD weft yarns. The paired MD warp yarns are interwoven with the second system of CD weft yarns so as to be intrinsic to the first layer and to bond the second layer to the first layer. The second system of MD warp yarns forms a long float, or warp runner, on the outer surface of the second layer. The first layer is present on the fabric forming side and the second layer is present on the fabric wear side. In this manner, triple layered fabrics having a pair of intrinsic binder and warp runners may be manufactured to have improved wear resistance on the wear side.

  Another aspect of the fabric according to the invention is that the MD warp yarns in pairs do not have an intrinsic nature in the second layer. The second layer paired with the warp helps to protect the binding point between each layer. Since each weft yarn on the wear side passes through the lower part of at least two successive wear side warp yarns, the warp yarn on the wear side may be more strongly covered to form a significantly different plane compared to prior art fabrics. .

  As another aspect of the present invention, the fabric according to the present invention comprises that the ratio of the first system of CD weft yarns to the second system of CD weft yarns has various ratios. The long floats described above may have different lengths. The fabric according to the invention may be plain weave or endless. Some of the yarns described above may have different diameters and / or shapes.

  The present invention will be described in detail below with reference to the drawings.

  For a more complete understanding of the present invention, the following description and drawings are set forth.

  A preferred embodiment according to the present invention is a triple layer fabric suitable for use in the forming section of a paper machine. The fabric according to the invention consists of an upper layer or forming layer and a lower layer or wear layer. Each layer is formed of interwoven machine direction (MD) or warp yarns and cross machine (CD) or weft yarns. Accordingly, the fabric according to the invention is formed of a forming side weft and a wear side weft having a forming side warp and a wear side warp.

  The forming layer and the wear layer are joined together with forming warp yarns interwoven with both forming weft yarn and wear side weft yarn. These warp yarns on the forming side are paired and have intrinsicity in at least the forming layer and, if possible, both of the above-mentioned layers. These are therefore referred to as a pair of intrinsic binders. Here, the term “intrinsic” means that the yarn is woven to provide fiber support to the upper layer, as opposed to simply bonding one layer to the other. To do.

  Another feature of the present invention is that the warp of the wear layer of the fabric is woven so as to form a long float on the outer wear side surface of the triple layer fabric according to the present invention. Here, “long float” means that the warp passes through the lower part of at least two wefts on the surface on the wear side. Thus, such long floats may pass under 2, 3, 4 or more yarns on the wear side. These long floats are also called warp runners. This float is the first point of contact between the fabric and the paper machine. Various warp yarns, or combinations of warp yarns, may be used to form the float; for example, the wear side warp, or the forming side warp, or both the wear side warp and the forming side warp forming the warp runner May be used for Further, each of the wear side warp and / or forming side warp, or some of them, may be used to form the warp runner. The length of the float may be in various ranges. These floats run in the MD direction and provide a relatively smooth fabric surface, thus reducing wear on the fabric caused by contact with stationary elements of the paper machine. In other words, the fabric warp runner according to the present invention improves wear resistance. The warp runner also helps reduce the load that occurs when this type of fabric travels on a paper machine.

  FIG. 1 shows a cross-sectional view of a preferred embodiment of a warp runner triple layer fabric having a pair of endogenous warp binders in accordance with the teachings of the present invention. In particular, FIG. 1 shows the warp boundary in the forming and wear layers for the W11 and W12 pairs of intrinsic binder yarns. The pair of warp yarns W11 and W12 are woven into the forming layer so as to be intrinsic and intersect to bond the wear layer. The pair of warp yarns W11 joins the wear layer in the weft yarn 23 and the pair of warp yarns W12 joins the wear layer in the weft yarn 8. The fabric according to the invention has a 2: 1 ratio, as is evident from twice the weft yarns (eg 1, 3, 4) in the forming layer relative to those in the wear layer (eg 2, 5, 8). Has a weft ratio. The wear side warp yarns W1 and the wear side warp yarns W2 weave the wear layer and form a pair of warp yarns with long floats from the weft yarns 2-11 and 17-26. In FIG. 1, the float length is shown as being 4, but a float length greater than 2 may be utilized. Further, the warp-side warp may be a pair of warp and / or a pair of warp.

  Additional advantages of the fabric according to the invention include relatively large weaving efficiency, reduced dimpling on the forming surface (initially due to the use of binder warp rather than weft), relatively low Includes calipers and appropriate void volume. The fabric according to the invention can be cleaned relatively easily, has a relatively long expected life, and is of this type due to a long wear side float that contacts the machine elements in the vertical direction. Has a relatively low driving load on a paper machine on which it runs.

  In another aspect of the invention, the fabric pattern may be formed to have a wear side weft ratio of 1: 1, 2: 1, 3: 1, 3: 2, or other ratios. Good. The fabric according to the invention may introduce yarns of different diameters or shapes. For example, the forming yarn may be a yarn having a smaller diameter than the wear yarn. Various dimension combinations of warp and weft yarns may be used. Moreover, the warp yarn and / or the weft yarn may be laminated or may not be laminated. For example, the forming-side wefts may or may not be laminated with respect to the wear-side wefts. These examples are merely representative of the invention and are not intended to limit the invention.

  The fabric according to the invention preferably has only monofilament yarns. CD and MD yarns may have a circular cross-sectional shape with one or more different diameters. Also, the forming side and wear side CD yarns and MD yarns may have different diameters. The forming CD and MD yarns preferably have a smaller diameter than the wear CD and MD yarns. However, in the present invention, the yarn diameters may be used in various combinations. Further, in addition to a circular cross-sectional shape, the one or more yarns may have other cross-sectional shapes, such as a square cross-sectional shape or a non-circular cross-sectional shape.

  The yarns described above may be monofilament yarns of circular cross-section of various synthetic polymer resins used in the manufacture of such yarns for paper machine fabrics. Two examples of such materials are polyesters and polyamides.

  Modifications to the above will be apparent to those skilled in the art, but such modifications do not depart from the scope of the invention. The appended claims should be construed to encompass such circumstances.

FIG. 3 shows a cross-sectional view of a preferred embodiment of a triple layer fabric of warp bonded and warp runners having a pair of intrinsic binders and a pair of warp runners in accordance with the teachings of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Weft yarn 2 Weft yarn 3 Weft yarn 4 Weft yarn 5 Weft yarn 6 Weft yarn 7 Weft yarn 8 Weft yarn 9 Weft yarn 10 Weft yarn 11 Weft yarn 17 Weft yarn 18 Weft yarn 19 Weft yarn 19 Weft yarn 19 Yarn 23 Weft yarn 24 Weft yarn 25 Weft yarn 26 Weft yarn W1 Warp yarn W2 Warp yarn W11 Pair of warp yarn W12 Pair of warp yarn

Claims (13)

A first layer formed of a first system of paired machine direction (MD) warp yarns interwoven with a first system of machine direction (CD) weft yarns;
A second layer formed of a second system of MD warp yarns interwoven with a second system of CD weft yarns;
A paper machine fabric having:
The paired MD warp yarns are intrinsic to the first layer or the second layer, and the CD weft yarn yarns are connected to the first layer so as to bond the second layer to the first layer. Interwoven with two systems;
The second system of MD warp yarns forms a long float on the outer surface of the second layer.   The paper machine fabric according to claim 1, wherein the paper machine fabric is a triple layered fabric. The first layer is present on the paper machine fabric forming side,
The paper machine fabric according to claim 1, wherein the second layer is present on the wear side of the paper machine fabric.   The paper machine fabric according to claim 1, wherein the long float on the outer surface improves the wear resistance of the paper machine fabric.   2. The paper machine fabric according to claim 1, wherein the ratio of the weft yarn of the first system of the CD weft yarn to the second system of the CD weft yarn is 2: 1. Paper machine cloth.   2. The paper machine fabric according to claim 1, wherein the ratio of the weft yarn of the first system of the CD weft yarn to the second system of the CD weft yarn is 1: 1. Paper machine cloth.   2. The papermaker's fabric of claim 1 wherein each long float yarn passes through at least two lower portions of said second system CD weft yarn.   The paper machine fabric according to claim 1, wherein the paper machine fabric is a plain weave or an endless form.   The papermaker's fabric of claim 1, wherein some of the yarns have different diameters.   The paper machine fabric according to claim 1, wherein at least some of the yarns have a non-circular cross-sectional shape.   The paper machine fabric according to claim 1, wherein some of the MD warp yarns are polyamide yarns or polyester yarns.   The paper machine fabric according to claim 1, wherein some of the CD weft yarns are polyamide yarns or polyester yarns.   2. The paper machine fabric according to claim 1, wherein the pair of MD warp yarns are intrinsic in the first layer and the second layer. 3.

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