MXPA96004375A - Spiral polyamide sewing for pa trainers - Google Patents

Abstract

The present invention relates to a machine-sewn papermaking fabric, endlessly lockable with a needle seam consisting of: a system of yarns (MD) with machine direction and a system of yarns (CD) with address Transverse to the machine, said yarns of said system of MD yarns are interwoven with said yarns of said system of CD yarns to form said paper-forming fabric in a rectangular shape with a length, a width, two longitudinal edges, and two edges to width, said MD yarns extend back and forth continuously along said length of said forming fabric between said two widthwise edges, said MD yarns further form seam loops along each of said two edges in width, said MD yarns are pleated / twisted, therefore, said pleated / twisted yarns form said seaming loops, a first seam spiral attached to said seams of seam in a or of said two edges in the width of said forming fabric by at least one connection yarn, and a second seaming spiral joined to said seaming loops in the other of said two edges across said forming fabric at least by a connecting yarn, wherein said forming fabric is joined in an endless manner by interdigitating said first and second seaming spirals and by directing a male through a passage defined by the interdigitated seam spirals to form a needle seam.

Description

SPIRAL POLYAMIDE SEWING FOR PAPER MANUFACTURER SEWED FABRICS FIELD OF THE INVENTION The present invention relates to the papermaking arts. More specifically, the present invention is a fabric of the paper manufacturer of the machine sewing variety, such as a WHO press fabric for the press section of a paper machine. DESCRIPTION OF PREVIOUS TECHNOLOGY During the papermaking process, a slurry is formed by depositing a fibrous runoff, which is an aqueous dispersion of cellulose fibers, into a moving fabric that is formed in the forming section of a factory. of paper . A large amount of water is drained from the runoff through the fabric formed during this process, leaving the fibrous waxy paste on the surface of the forming fabric. The newly formed gaseous paste passes from the forming section to the press section, which includes a series of joining points. The fibrous gaseous paste passes through the press points adjusted by a press fabric, or as is often the case, between two press fabrics. At the press junctions, the fibrous gill paste is subject to compressive forces, which squeeze the water that exists in it, and which adhere the fibers in the paste watered with each other to convert fibrous gill paste in a sheet. Fabrics or press fabrics accept water, and ideally do not return to watery paste. Finally, the slurry proceeds to the drying section, which includes at least a series of rotary drums, drums or cylinders, which are internally heated by steam. The slurry, or the newly formed paper sheet, itself is directed towards a sinuous passage sequentially around each of the series of drums by a drying cloth, which keeps the watery paste close against the surfaces of the drums. The hot drums reduce the water content of the watery paste to a desirable level through evaporation. It should be appreciated that the forming fabric, the press and the drying fabrics, all take the form of endless loops in the paper machine and function in the manner of conveyors. It should also be noted that the manufacture of paper is a continuous process which is carried out at a considerable speed. That is, the fibrous runoff is continually deposited on the forming fabric in the forming section, while a freshly made sheet of paper is continuously rolled into rolls after it leaves the drying section.

Referring, for the moment, specifically to press fabrics, it should be remembered that, in a moment, the press fabrics were only supplied in endless form. This is because a newly formed sheet of paper is extremely susceptible to being marked at the junction points of the press by any non-computer in the fabrics or press fabrics. A seamless, endless fabric, such as that produced by the known process in an endless fabric, has a uniform structure, both in its longitudinal direction (machine), and in its transverse direction (transversal machine). A seam, such as a seam that can be used to close a press fabric in an endless manner during installation in a paper machine, represents a discontinuity in the uniform structure of the press fabric. Then, the use of a seam greatly increases the similarity that the sheet of paper will be marked at the points of attachment of the press. In short, the sewing region of any OMS press fabric for machine sewing, must behave under any load, that is, under compression at the points of attachment of the press or at the points of attachment, as the rest of the press fabric, and must have the same water permeability, in order to prevent periodic marking of the paper product that is manufactured by the sewing region. OMS is a registered trademark of Albany International Corp.

In spite of the considerable technical obstacles that these requirements presented, it remained highly desirable to develop a machine sewing press (OMS), due to the comparative ease and safety with which it can be installed in the press section. Lately, these obstacles were overcome with the development of press fabrics having seams formed by providing seaming loops at the transverse edges of the two ends of the fabric. The loops by themselves, are formed by the yarns with address of the machine (MD) of the fabrics. A so-called "pin seam" is formed by joining the two ends of the press fabric, by interdigitating the loops of the seam at the two ends of the fabric, and by directing the so-called pin or male through the passage defined by Interdigitated seam loops to close the two ends of the fabric together. It does not need to be mentioned, that it is much easier and much less time-consuming to install a WHO press fabric than to install an endless press fabric on a paper machine. One method for manufacturing a press fabric that can be joined in a paper machine with a "pin seam" is to wind the fabric in a flat form. In this case, the twisted yarns are the yarns (MD) in the direction of the press fabric machine. To form the seam loops, the twisted ends are spun some distance backward within the body of the fabric in a direction parallel to the twisted yarns. Another, more preferable, technique is a modified form of endless spinning, which is normally used to make an endless loop of fabric. In the modified endless yarn, the weft, or fill yarns are spun continuously back and forth along the loom, in each passage a loop is formed at one of the edges of the fabric that is hi-side when going around a loop forming needle. According to the weft yarn, or filling yarn, which in the end becomes an MD yarn in the press fabric, is continuous, the seam loops obtained in this way are stronger than any other that can be manufactured by spinning the twisted ends back to the ends of a fabric spun flat. Originally, single monofilament fibers were used both in the machine direction or in the cross machine direction of the OMS press fabrics. The relative stiffness of the monofilament ensures that it will have the required properties required of the seam loop formation. Experience has shown, however, that single monofilament fibers are difficult to spin and do not have enough elasticity in the machine direction for many kinds of contemporary presses. Frequently, tension failures and seam rupture were observed. Another difficulty arises due to the incompressible, rigid and very open structure of the base fabrics, spun from single monofilaments. For some papermaking applications, this lack of compression is not a problem, and may even be ideal. However, for positions that have a poor auxiliary ability to dewater the fabric, or produce paper grades sensitive to the mark, a more compressible base fabric is needed. A more compressible base fabric can be obtained by spinning yarns with multiple filaments or pleated monofilaments, instead of single monofilament fibers. However, yarns of this type do not have the necessary stiffness for the good formation of loops or to maintain the integrity of the seam area during the loosening of the loops, when the seam is going to be closed. In addition, because the yarns of this type are twisted, the formed loops tend to rotate about their axes lying in the planes of the loops. When this rotation occurs, known as the secondary spiral effect, it causes the yarns to differ from the ideal orientation necessary to form the needle seam. Such separation makes it difficult, if not impossible, to interdigitate the loops at each end of the press fabric during the closure, as well as to direct the male through the passage defined by the interdigitated loops. In the prior art some attempts have been made to overcome these difficulties by making the MD yarns forming loops act as monofilaments. In U.S. Pat. No. 5,005,610 MD yarns in a OMS fabric of the paper manufacturer, has a composite structure that includes braided monofilament fibers. The braided yarn forms seam loops, which resist deformation and because they are balanced with respect to the torsion, form seam loops that are not susceptible to the rotation of "spiral side effect" from the ideal flat geometry of the seam. sewing. In U.S. Pat. No. 5,204,150, the MD yarns in a WHO fabric of the paper manufacturer are pleated / twisted yarns extruded from a resin that partially melts during the heat setting of the fabric, giving the MD yarns a character similar to the monofilament. Although not balanced due to twisting and pleating, the melting caused by the partial melting of the individual ends prevents the rotation of the loop of the ideal geometry of the seam. Finally, in U.S. Pat. No. 5,391,419, the MD yarns of a needle sewing fabric of the paper manufacturer are pleated / twisted and have a coating which provides the yarn with a structure similar to that of the monofilament. The coating can be permanent, semi-permanent or soluble. Although the yarns are not balanced, the coating prevents the rotation of the loop. The present invention is a different approach to providing a OMS fabric from the paper manufacturer having MD yarns pleated / twisted with seam loops similar to those of the monofilament. DESCRIPTION OF THE INVENTION Accordingly, the object of the present invention is to provide a WHO fabric of the paper manufacturer having MD yarns pleated / twisted with monofilament seams of lacing. A pleated / twisted yarn signifies any variety of yarn used in the production of paper machine clothes that have multiple ends or filaments, which are twisted to the desired degree, and, in many cases, are then combined or pleated with other filaments of the same type or of a different kind. During the operation of the pleating, the components of the yarn are combined together by twisting them in the opposite direction from that of the individual components. Pleated / twisted yarns can be considered, according to this, as multi-component yarns. This objective is achieved with the present OMS fabric of the paper manufacturer, which is woven with an endless weaving technique from an MD yarn system and a yarn system (CD) with machine direction, where the MD yarns they are pleated / twisted, like multi-strand yarns or pleated monofilaments. The fabric of the paper manufacturer has a rectangular shape with one length, one width, two longitudinal edges and two edges in width. The pleated / twisted MD yarns extend back and forth continuously over the length of the fabric of the paper manufacturer between the two edges at widths, at each edge widthwise, forming a plurality of seaming loops. Seam loops, formed from the pleated / twisted yarns, are susceptible to the problems discussed above, and tend to differ from the preferred orientation and take shape as soon as the loop forming needle is removed, around which they are formed. during the endless weaving process. In accordance with the present invention, concurrent with the removal of the loop forming needle, the monofilament stitching spirals are interdigitated with and attached to the seaming loops at each edge across the width of the fabric., before the seam loops have the opportunity to differ from the orientation and the preferred shape. The monofilament stitching spirals are in-tones used to close the fabric in an endless form in a paper machine with a needle stitching. The present invention will now be described in more detail, with reference to the figures, which may be identified as follows. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic perspective view of a press fabric (OMS) sewn by machine; Figure 2 is a schematic perspective view of the two ends of the WHO press fabric prior to being joined to another; Figure 3 is a cross-sectional view, taken in the direction of the twist of the paper manufacturer's fabric; Figure 4 is a cross-sectional view, taken in the direction of the weft, of the seam region of the fabric, prior to the removal of the lacing needle from it; and Figure 5 is a cross-sectional view, taken in the machine direction, of the seam region of the fabric following its installation in the paper machine. DETAILED DESCRIPTION OF THE PREFERRED INCORPORATION Returning now specifically to the figures, the Figure 1 is a schematic perspective view of the OMS fabric 10 of the machine sewn paper manufacturer. The fabric 10 takes the form of an endless loop once its two ends 12, 14 have been joined to one another in the seam 16. Figure 2 is a schematic perspective view of the two ends 12, 14 of the WHO 10 fabric prior to its union with another. Widely, along the edges of each of the two ends 12, 14, there is a plurality of seaming loops 18. In order to join the two ends 12, 14 to one another, they join together, and to do so, the seaming loops 18 at each end alternate with each other and are mutually interfered with, or interdigitated. The interdigitated seam loops 18 define a passage through which a pin, a thread similar to the yarn or member, can be directed to secure the ends 12, 14 to one another. This is where the term "needle sewing" is born. In the present invention, the seaming loops 18 are provided in a new and unique manner. Figure 3 shows a cross-section, taken in the direction of the twist, of the papermaking fabric 20, in which the present invention can be practiced. Fabric 20 woven with a double fabric is shown, although it should be understood that such fabric is shown only as an example, and that the invention can be practiced with fabrics 29 that are woven into single-layered fabrics, or that are laminated and include some layers of cloth. The fabric 20 can be a base fabric for a press fabric, and accordingly, it can be embroidered with one or more layers of fibrous strand filling material on one or both sides, or it can be coated in some way. Alternatively, the fabric 20 can be used in one of the other sections of the paper machine, that is, in the forming or drying sections, or as a base for a process band of the paper industry for coating of polymer resin. The fabric 20 is woven in a modified process of endless fabric. In this situation, yarns 22 twisted at the end are converted into yarns (MD) with cross direction to the machine, and the weft yarns 24 at the end become yarns (MD) towards the machine, when reference is made to the directions of the yarns, is in relation to the paper machine in which the cloth 20 is installed. The twist yarns 22, the CD yarns in the OMS fabric, can be any kind of yarn used to weave clothes in paper machines. That is to say, the monofilament yarns, which are strands of independently used monofilaments, or pleated / twisted yarns, can be used as twist yarns 22. On the other hand, the weft yarns 24, which are the MD yarns in the OMS fabric, are pleated / twisted yarns. In the present context, as defined above, these yarns can be multifilament yarns or pleated monofilament yarns, that is, these yarns can be any of the continuous filament yarn forms, except the monofilament yarns. used independently or alone. For example, the weft threads 24 may be pleated monofilament yarns of one of the following types: a) 0.26 mm x 1 x 3, three strands of 0.26 mm diameter yarn individually twisted, and then pleated together when twisting one with the other in the opposite direction; or b) 0.30 mm x 1 x 3, three threads of 0.30 mm in diameter of yarn twisted individually, and then plissed together when twisting with each other in the opposite direction. In addition, the weft threads 24 may be spun yarns (spun yarns of filament fibers) or combinations yarns, wherein the yarns of more than one of the above-mentioned varieties are combined with another by crimping, twisting or both. In addition, the weft yarns 24 may be multiple strand yarns consisting of a plurality of single strands pleated / twisted together, each filament has a diameter within the limit of 0.05 mm to 0.15 mm. For example, a yarn of multiple strands may consist of three bundles, each consisting of eight strands of 0.10 mm in diameter of yarn, twisted one with the other in one direction, the three bundles being twisted together with one another. the opposite direction (0.10 mm x 8 x 3). In any case, the filaments comprising the twist yarns 22 (CD yarns) and the weft yarns 24 are extruded from polymeric resin materials, such as polyamide, polyester, polyether-ketones, polypropylenes, polyaramides, polyolefins and resins. of polyethylene teraphthalate (PET), are incorporated into yarns according to techniques well known in the textile industry and particularly in the paper machine clothing industry. In the fabric of the fabric 20 by the endless modified fabric, the weft yarns 24 are continuously woven back and forth along the loom, in each passage along the same, form a loop at one of the edges of the fabric 20, which is woven when passing around a loop forming ne. For weaving fabrics by the endless modified fabric, some schemes are available, discovered and claimed in U.S. Pat. No. 3,815,645, to Codorniu, whose teachings are incorporated herein by reference, and may be used in the practice of the present invention.

Figure 4 is a cross section taken along the direction of the weft, of the seam region of the fabric 20, taken at the conclusion of the modified endless woven process. The web yarns 24, which at the end are the MD yarns of the fabric 20, are woven around a loop forming needle 26 in a continuous manner to provide the seaming loops 18. It will be appreciated that the lacing needle 26 must be removed to place the fabric 20 in a form in which it can be quickly installed in the paper machine. It will also be appreciated that, because the weft yarns 24 (MD yarns) are pleated / twisted, the seam loops 18 can rotate from the ideal seam geometry, illustrate the spiral side effect, and deform as soon as the loop forming needle 26 is removed, resulting in difficult or impossible stitching on the paper machine. Figure 5 is a cross-section, taken in the machine direction, of the seam region of the fabric 20 taken in the installation of the paper machine. The problem of joining the ends of a fabric having the seam loops 18 formed by pleated / twisted yarns is solved by joining seam coils 28 to the seam loops 18 concurrently with the removal of the lacing needle 26.

Specifically, a lacing needle 26 is pulled out of the passage defined by the interdigitated seaming loops 18, a seaming spiral 28 is attached to each seaming lacing 18 as soon as the lacing needle 26 is pulled out and before that the lacing 18 has the opportunity to deform or rotate from its preferred orientation. Therefore, the seaming coils 28 are interdigitated with the seaming loops 18 one by one as the lacing needle 26 is pulled out. The seaming coils 28 are joined to the seaming loops 18 by connecting the threads 30, which are directed through the seaming loops 18 as soon as the seaming coils 28 are in place. At the conclusion of this process, a OMS fabric having pleated / twisted yarns in the machine direction and monofilament seaming loops provided by the seaming coils 28 has been obtained. Customarily, one or more layers of fibrous strand filling material, not shown in Figure 5, is embroidered to the fabric 20. Preferably, this is done before the lacing needle 26 is removed from the seaming loops 18. and that the seaming coils 28 are installed, although the order of these operations can be changed. However, when the seaming coils 28 are installed before embroidery, the embroidery operation by itself can cause them some damage and will require their replacement. The embroidery prior to the removal of the loop forming needle 26 is preferred for this reason. The seam spirals 28 with mono-filament spirals, preferably of polyamide extruded resin. The diameter of the monofilament can be, for example, 0.40 m or 0.50 mm. During the installation of the fabric 20 in a paper machine, the seaming coils 28, which are monofilament, can be rapidly interdigitated with each other and joined to each other by directing the male 32 through the defined passage. by interdigitated spirals. The filling yarns 34 can be inserted into the seaming spirals 28 to ensure that the stitching region has the same characteristics as the rest of the fabric 20. The connecting threads 30 and the filling yarns 34 can be yarns of the yarns. same classes used in the twisted yarns 22 (CD yarns) of the fabric 20. The male 32 can be of a single strand of monofilament, multiple strands and monofilaments without twisting with one another, or pleating, twisting, braiding or stitching together, one or more strands of any pleated / twisted yarn described above for use as the MD yarns (weft 24) of the fabric 20. The male 32 may be a single strand of monofilamentmultiple strands of monofilaments, multiple strands of monofilaments without twisting with each other, or pleating, twisting, braiding or stitching together, or one or more strands of any of the pleated / twisted yarns described above for use as yarns MD (weft yarns 24) of the fabric 20. Modifications to the foregoing will be obvious to those of ordinary skill in the art, but will not present the invention so modified as to exceed the scope of the attached clauses.

Claims (12)

1. NOVELTY OF THE INVENTION Having described the invention, it is considered as a novelty, and therefore, the content of the following clauses is claimed as property. CLAUSES 1. A fabric from the machine-sewn paper manufacturer, which can be closed in endless form with a needle stitch consisting of: a yarn sm (MD) with address to the machine and a yarn sm (CD) with address transverse to the machine, said yarns of said MD yarn sm are interwoven with said yarns of said CD yarn sm to form said papermaking cloth in a rectangular shape with a length, a width, two longitudinal edges, and two edges in width, said MD yarns extend back and forth continuously along said length of said manufacturer's fabric between said two widthwise edges, said MD yarns further form seam loops along each of said two edges in width, said MD yarns are pleated / twisted, therefore, said pleated / twisted yarns form said seams of seam, a first seam spiral attached to said seams of seam in one of said two edges across the width of said manufacturer's fabric, at least by a connecting yarn; and a second seam spiral attached to said seaming loops in the other of said two edges across said manufacturer's fabric at least by a connection yarn; wherein said manufacturer's fabric is joined in an endless manner by interdigitating said first and second seaming spirals and by directing a male through a passage defined by the interdigitated seam spirals to form a needle seam.
2. 2. A fabric of the paper manufacturer as claimed in clause 1, wherein said first and second coils are monofilament coils.
3. 3. A fabric of the paper manufacturer as claimed in clause 2, wherein said monofilament coils are extruded from a polyamide resin.
4. 4. A fabric of the paper manufacturer as claimed in clause 1, wherein said pleated / twisted yarns are multi-filament yarns.
5. 5. A fabric of the paper manufacturer as claimed in clause 1, wherein said pleated / twisted yarns are monofilament yarns.
6. 6. A fabric of the paper manufacturer as claimed in clause 1, wherein said folded / twisted yarns are yarns of multiple strands that consist of stitching. a plurality of single filaments, each filament having a diameter within the limit of 0.05 mm to 0.15 mm.
7. 7. A fabric of the paper manufacturer as claimed in clause 1, wherein said pleated / twisted yarns are spun yarns.
8. 8. A fabric of the paper manufacturer as claimed in clause 1, wherein said pleated / twisted yarns are combination yarns.
9. 9. A fabric of the paper manufacturer as claimed in clause 1, wherein said pleated / twisted yarns include extruded filaments of a polymeric resin material.
10. 10. A fabric of the paper manufacturer as claimed in clause 1, wherein said polymeric resin material is selected from the group consisting of polyamide, polyester, polyether, polypropylene, polyaramide, polyolefins and polyethylene terephthalate resins ( PET).
11. 11. A fabric of the paper manufacturer as recited in clause 1, which also consists of at least one yarn of filling within the first seam spiral.
12. 12. A fabric of the paper manufacturer as claimed in clause 1, which also comprises at least one yarn of filling within said second spiral of