Spiral winding press felt with orthogonal seam rings and method

Abstract

A seamed press felt includes a base fabric having an MD length and a CD width, and including MD oriented yarns fixed in place by additional fabric material components. The MD-oriented yarns are arranged in the base fabric as two overlapping layers that are joined by return bend regions at CD-oriented fold regions at opposite ends. Additional fabric material components are removed from the MD oriented yarns in the folded regions to form seam regions. The CD yarns are interwoven with the MD-oriented yarns in the folded regions across the CD width of the base fabric and form respective woven regions adjacent to seam loops formed by back-bending regions of the MD-oriented yarns at the CD folded regions. The woven region anchors the MD oriented yarn at the folded region such that the seam loop is uniformly formed across the CD width of the press felt.

Description

[0001] Cross-reference to related patent applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 356,615, filed on June 29, 2022, which is incorporated herein by reference as if fully set forth. Technical Field

[0003] The present invention relates generally to seamed press felts used in papermaking machines or similar machines for producing paper and similar products. More particularly, it relates to the seams of spirally joined felts. The novel construction helps prevent loop stretching and provides loop anchoring. Background Art

[0004] The present invention relates to press felts used in the press section of a paper machine. In the production of paper products, a stock slurry consisting of about 1% papermaking fibers and other solids dispersed in about 99% water is transferred at high speed and high precision from a headbox slice to a fast moving forming fabric in the forming section of the paper machine, or between two forming fabrics. The stock is subjected to agitation and dewatering by various mechanisms of the forming fabric, leaving a loose, tacky, wet web of fibers. The web is then transferred to the press section where a further portion of the water is removed by mechanical mechanisms as the web passes through at least one, and usually a series of, press nips supported by one or more press felts, where the water is substantially squeezed out of the nascent paper and into the press felts. The water is received by the press felts and, ideally, no water is returned to the web. The resulting paper is then passed to a drying section comprising a series of rotatable drying cylinders or cans heated by steam. One or more drying fabrics guide the paper around the periphery of the cylinders and maintain it in contact therewith so that most of the residual moisture is removed by evaporation.

[0005] Press felts play a key role in the production of paper products. Known press felts are manufactured in a wide variety of ways designed to meet the requirements of the papermaking machines on which they are mounted to produce various paper grades. Generally, they are assembled using a woven or nonwoven base fabric structure into which one and usually multiple layers of a fibrous nonwoven batt are needled. The batt provides a smooth surface for carrying the paper product; acts as a reservoir to retain moisture pressed out at the press nip; and provides a measure of the resilience of the press felt as it passes through the nip. The base fabric is typically woven from monofilament, cabled monofilament, multifilament, or similar multicomponent yarns; they may also be arranged in a nonwoven planar array. The component yarns are typically composed of an extruded polymer resin, typically a polyamide.

[0006] The base fabrics may be of single or multi-layer construction, or they may be formed of two or more layers laminated together. They may be endlessly woven, so that the resulting fabric is like a tube without seams; such fabrics must be prepared to the length and width of the machine for which they are intended, and must be slid onto the press section in a manner similar to socks. An example of such a fabric is provided in US 7,118,651. In a variant of the modified endless weaving technique, during production, the weft yarns are used to form seaming loops at the weft fabric edges; when installed on a paper machine, these yarns will be oriented in the intended machine direction (MD) so that the fabric is joined by bringing the loops on each side together and inserting a pin or pivot through the resulting channel formed by the interlocking loops. An example of a modified endlessly woven fabric can be found in US 3,815,645. The base fabric may also be woven flat using one or more layers of warp and weft yarns; seams are usually formed at each end to join the fabric to the machine. An example of a flat woven base fabric can be found in US 7,892, 402. All of the above configurations require that the base fabric be woven to the full width and length of the intended machine.

[0007] To reduce production time and cost, so-called "multiaxial fabrics" have recently been introduced into the manufacture of press felts. Multiaxial press felts are well known and described in US 5,360,656, US 5,268,076, US 5,785,818 and other patents. The base fabric of these press felts consists of a plurality of spirally wound and edge-jointed material strips, which contain at least machine direction (MD) oriented yarns. The material strips are typically flat woven fabrics narrower than the width of the intended base fabric of which the material strips are a component. It has also been suggested to use a nonwoven array of MD yarns as a material strip component. Regardless of whether the component is woven or nonwoven, during assembly, each turn of the material strip is guided around two opposing rollers so that its component MD yarns are inclined at a small angle of about 1° to about 8° relative to the intended MD of the finished fabric; see prior art Figure 1. Each continuous turn of the material strip is joined to the adjacent turns of the material strip along the edges to construct a continuous tubular base fabric of the desired width and length. When the tube is removed from the assembly roll and laid flat, the tube has continuous top and bottom surfaces at each of the two opposite ends joined at a cross-machine direction (CD) oriented fold region; see prior art Figure 2. The finished multiaxial base fabric is typically one of a two, three or four layer construction comprising a spirally wound continuous tube top and bottom surface and optionally at least one additional flat fabric layer atop the interior or one or both exterior surfaces of the flattened tube. The combined base fabrics may then be provided with seams to facilitate their installation on their intended machines.

[0008] Figure 3 shows two opposing edge regions of a spirally wound prior art double layer woven structure with a portion of the CD oriented yarn removed at opposing fold regions. This exposes the MD oriented yarns of the structure so that the yarn loops can be used to form a seam in the fabric, as illustrated in Figure 4. This figure shows a double layer fabric that has been pivotally stitched by nesting the yarn loops formed by the MD yarns at the fold regions and inserting a pivot stitch across the length of the channel provided thereby.

[0009] For seamed press felts, and especially in the case of press felts based on multiaxial fabrics, there are several issues associated with the seams. These issues include: differences in the physical properties of the fabric in the seam area leading to different elasticity and different air permeability, which can lead to paper breaks, as the strength of the sheet is lower at the seam mark; and marking of the finished paper. Therefore, the seam area is usually considered the most critical area of ​​the finished fabric.

[0010] One previously suggested solution is disclosed in US Pat. No. 7,381,308 B2 to Albany International Corp., in which the CD yarns are removed to create the seam gaps and then rewoven into the fabric at each fold along the edges of the ravel area.

[0011] Further problems with these seam constructions include loop stretching and poor seam loop stability, and tilting of the MD seam loops in a multi-axial configuration results in uneven and more difficult seaming.

[0012] It would be desirable to provide a press felt base fabric construction that improves upon the known stability and stretching problems at seams, and in particular to provide a multi-axial press felt construction. Summary of the invention

[0013] It would be desirable to provide a seam in which the loops are anchored within the felt and do not pull out, stick out, or slide out. The seam constructions provided herein address some or all of these issues.

[0014] In one aspect, a seamed press felt is provided, comprising: a base fabric having an MD length and a CD width, and comprising at least MD oriented yarns held in place by an additional fabric material component. The MD oriented yarns are arranged in two overlapping layers in the base fabric, and the two overlapping layers are connected by a return bend area of ​​the MD oriented yarns at a CD oriented fold area at each of two opposite ends of the base fabric. The additional fabric material component is removed from the MD oriented yarns in the CD oriented fold area to form a seam area. Each CD yarn is interwoven across the CD width of the base fabric with the MD oriented yarns in each of the overlapping layers in the CD oriented fold area forming each woven area, and each woven area is located adjacent to the seam loop formed by the return bend area of ​​the MD oriented yarns at the CD fold area. The woven area anchors the MD oriented yarns at the CD oriented fold area so that the seam loop is uniformly formed across the CD width of the press felt. A pivot extends from the two opposite ends through a channel defined by the mutually nested seam loops to form a seam.

[0015] In one embodiment, the woven region includes an increased flex interlacing of CD yarns with MD oriented yarns, preferably a factor of 2. For example, the woven region is preferably woven in a plain weave relative to a nonwoven used in the base fabric or a woven fabric with less interlacing (such as a woven fabric or twill with long floats).

[0016] In another embodiment, the base fabric comprises a spirally wound strip of material having a width less than the CD width of the base fabric.The spirally wound strip of material may be made of joined nonwoven or woven materials.

[0017] In another embodiment, the seam area is oriented at 90 degrees to the machine direction of the press felt.

[0018] A particular benefit of a multiaxial (spiral wound) construction is that the woven regions anchor the MD oriented yarns at the CD oriented fold regions so that the seaming loops extend in the true machine direction of the base fabric.

[0019] In another embodiment, the diameter of the CD yarns in the woven area is selected to maintain a consistent caliper between the body of the press felt and the seam area.

[0020] In another embodiment, at least some of the woven regions comprise bicomponent at least partially fusible CD yarns adjacent to the additional fabric material component bordering the woven regions at the CD oriented fold regions.

[0021] In another embodiment, the woven regions each comprise at least one fill yarn, the fill yarn being located adjacent to the seaming loops formed by the MD oriented yarns at the CD fold regions. More preferably, the at least one fill yarn is a multifilament yarn.

[0022] In another embodiment, the woven regions each contain at least two monofilament yarns interwoven with the MD oriented yarns.

[0023] The seamed pressed felt may comprise a strip of surface material connected to a woven area. More preferably, the strip of surface material may be connected to the woven area by adhesive, heat or pressure means.

[0024] In the preferred application of press felt, the batt is needle stitched to the base fabric and the woven area.

[0025] In another aspect, a method of making a seamed pressed felt is provided, the method comprising: providing a base fabric formed into a tube having an MD length and a CD width, formed from a spirally wound strip of material having a width less than the CD width of the base fabric, and comprising at least MD oriented yarns held in place by an additional fabric material component; removing the additional fabric material component from the MD oriented yarns in the CD regions at two opposing MD ends of the tube to form respective seam regions; interweaving respective CD yarns across the CD width of the base fabric with the MD oriented yarns in the seam regions to form respective woven regions, wherein in the finished seamed pressed felt, the respective woven regions are adapted to be located relative to the seam loops. The invention relates to a method for forming a press felt in a press felt having a seam loop formed by a return region of MD oriented yarns at each of the CD fold regions; interweaving a spacer yarn with the MD oriented yarns in the seam loop forming region between the woven regions at each of the CD fold regions; folding the tube so that the MD oriented yarns in the base fabric are arranged in two overlapping layers connected by the return regions of MD oriented yarns at the seam regions at two opposite MD ends; removing the spacer yarns from the MD oriented yarns at the seam loop forming region so that the seam loops are uniformly formed across the CD width of the press felt; and inserting a pivot through a channel defined by nesting the seam loops from the two opposite ends to form a seam. More preferably, removing the spacer yarns from the MD oriented yarns at the seam loop forming region is completed before flattening the tube.

[0026] In another aspect, the method further comprises: stabilizing the woven region by interweaving bicomponent at least partially fusible CD yarns adjacent to the additional fabric material component bordering the woven region at the CD oriented fold region; and at least partially melting the bicomponent at least partially fusible CD yarns to anchor the woven region to the additional fabric material component bordering the woven region at the CD oriented fold region.

[0027] In another aspect, the method further comprises stabilizing the woven region using an at least partially fusible scrim.

[0028] In another aspect, the method further comprises stabilizing using a heat activated adhesive layer.

[0029] In another aspect, the method further comprises needle stitching a batt layer to the base fabric and the woven region at each of the CD fold regions.

[0030] The features indicated above may be used alone or in combination with other features indicated. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above Summary of the Invention and the following Detailed Description and Claims will be best understood when read in conjunction with the accompanying drawings, which illustrate currently preferred embodiments of the invention. In the drawings:

[0032] 1 is an illustrative diagram showing a known spiral winding process in which a relatively narrow strip of fabric 10 is spirally wound from a feed source 20 between two opposed rollers 22, 24 to produce a base fabric of a desired width and length. In this process, each successive turn of the strip 10 is joined with the turn disposed adjacent thereto to provide the base fabric.

[0033] FIG. 2 is a view of a known continuous tubular base fabric 30 including opposed fold regions 32 and 34; fabric 30 may be made from continuous turns of narrow fabric 10 in the manner illustrated in FIG. 1 , it may also be made from a modified endless weaving process, a flat weaving process that joins opposed ends of a flat woven fabric to provide a continuous tube, or it may be a nonwoven adhesive assembly of yarns oriented lengthwise around the tube.

[0034] FIG. 3 is an enlargement of two folded edge regions 32, 34 of the base fabric 30 shown in FIG. 2 that form the seam region in the prior art fabric shown in FIGS. 1 and 2;

[0035] Figure 4 is a schematic illustration of a seam area of ​​a pivot 18 including a seam area joining folded ends 32, 34 in a prior art base fabric 30 such as shown in Figures 1 to 3. This is shown prior to needle sewing one or more batt layers to the base fabric 30.

[0036] 5 is a top view of a seam area 40 of a prior art multiaxial base fabric 30 before the tube is folded to form a seaming loop.

[0037] 6 is a side view of a dual layer seam gap of a prior art multiaxial substrate.

[0038] 7 is a side view of the seam area of ​​a prior art folded double layer multiaxial base fabric with both ends joined and pivotally inserted into the channels formed by the seaming loops.

[0039] 8 is a view similar to FIG. 7 after the batt has been needle-sewn to both surfaces of the press felt according to the prior art.

[0040] 9 is a view of FIG. 8 depicting cumulative filament stretch and filament slippage within the batt and weft yarns at the seam loops within a press felt according to the prior art.

[0041] 10 is a front view of a seaming loop when using a prior art multiaxial base fabric as viewed from the direction of travel.

[0042] Fig.11 is a top view of the seam area of ​​a multiaxial base fabric of the present invention having CD yarns interwoven within the seam edge.

[0043] Fig.12 is a side view of a double layer seam gap of a multiaxial base fabric of the present invention with CD yarns interwoven within the seam edge.

[0044] Fig.13 is a side view of the seam area of ​​a folded, two-layer, multiaxial base fabric of the present invention with the ends joined and the pivots inserted into the channels formed by the seaming loops and the CD yarns interwoven within the seam edges.

[0045] Fig.14 is a front view of the seam loops as viewed from the direction of travel for a multiaxial base fabric of the present invention having CD yarns interwoven within the seam edges.

[0046] 15 is a top view of a seam area of ​​a prior art nonwoven substrate.

[0047] 16 is a side view of a double layer seam gap of a prior art nonwoven base fabric.

[0048] 17 is a side view of the seam area of ​​a prior art folded double layer nonwoven base fabric with both ends joined and pivotally inserted into the channel formed by the seaming loops.

[0049] 18 is a front view of the seaming loops as viewed from the direction of travel for a prior art double layer nonwoven base fabric.

[0050] 19 is a view of FIG. 17 after the batt has been needle-sewn to both surfaces of the press felt.

[0051] 20 is a view of FIG. 19 depicting cumulative yarn stretching and yarn slippage within the batt layer and weft yarns at the seam loops in the press felt according to the prior art shown in FIG. 19 .

[0052] 21 is a front view of the seaming loops for a prior art nonwoven base fabric as viewed from the direction of travel.

[0053] Fig. 22 is a top view of a seam area of ​​a nonwoven base fabric of the present invention with CD yarns interwoven within the seam edge.

[0054] Fig.23is a side view of the seam gap of a double layer nonwoven base fabric of the present invention with CD yarns interwoven within the seam edge.

[0055] Fig.24 is a side view of the seam area of ​​a folded, double-layer nonwoven base fabric of the present invention with the ends joined and the pivot inserted into the channel formed by the seaming loops and the CD yarns interwoven within the seam edges.

[0056] Fig.25 is a front view of the seaming loops as viewed from the direction of travel of the nonwoven base fabric of the present invention with the CD yarns interwoven within the seam edges.

[0057] Fig.26 After the batt is sewn to the two surfaces of the felt, Fig.24 Similar view.

[0058] Fig. 27 is a front view of the seaming loops when viewed from the direction of travel of the nonwoven base fabric of the present invention with the CD yarns interwoven within the seam edges.

[0059] 28 is a top view of a seam area of ​​a prior art multiaxial base fabric.

[0060] 29 is a side view of a single layer seam gap of a prior art multiaxial base fabric.

[0061] 30 is a side view of the seam area of ​​a prior art folded double layer multiaxial base fabric with both ends joined and pivotally inserted into the channels formed by the seaming loops.

[0062] 31 is a front view of a seaming loop when viewed from the direction of travel when using a prior art multiaxial base fabric.

[0063] Fig.32 is a top view of the seam area of ​​a multiaxial base fabric of the present invention having CD yarns interwoven within the seam edge.

[0064] Fig.33 is a side view of a single layer seam gap of a multiaxial base fabric of the present invention with CD yarns interwoven within the seam edge.

[0065] Fig.34 is a side view of the seam area of ​​a folded, two-layer, multiaxial base fabric of the present invention with the CD yarns interwoven within the seam edges, bound at the ends and pivotally inserted into the channels formed by the seam loops.

[0066] Fig.35 is a front view of the seam loop when viewed from the direction of travel when using a multiaxial base fabric of the present invention with CD yarns interwoven within the seam edge.

[0067] Fig.36is a side view of the seam area of ​​a folded, two-layer, multiaxial base fabric of the present invention with CD yarns interwoven within the seam edges, the ends bound and pivotally inserted into the channels formed by the seam loops, and additional sewing in the seam area.

[0068] Fig.37 is a front view of the seam loops for a multiaxial base fabric of the present invention having CD yarns interwoven within the seam edges and additional stitching in the seam area as viewed in the direction of travel.

[0069] Fig.38 is a side view of a seam area of ​​a prior art folded double layer nonwoven base fabric with both ends joined and pivotally inserted into a channel formed by a seam loop and additional stitching in the seam area.

[0070] Fig.39 is a front view of the seaming loops when viewed in the direction of travel when using the nonwoven base fabric of the present invention with CD yarns interwoven within the seam edges and additional stitching in the seam area.

[0071] Fig.40 is with Fig.13 A view similarly shows a scrim or tape in the region between the additional textile material component and the woven region for bonding the additional textile material component to the woven region.

[0072] Fig.41 is with Fig.33 A similar view showing optional spacer yarns woven between filler yarns.

[0073] Fig.42 is a flow chart illustrating a method for making a seamed press felt according to a preferred aspect of the present disclosure. DETAILED DESCRIPTION

[0074] Certain terms are used in the following description for convenience only and are not limiting. The words "top", "bottom", "upper" and "lower" indicate directions in the accompanying drawings to which reference is made. Reference to a list of items listed as "at least one of a, b or c" (where a, b and c represent the listed items) means any single item or combination of items a, b or c. "A" or "an" refers to one or more of the items indicated. "MD" refers to the machine direction of a paper machine from the headbox to the drying section and is the longitudinal direction of the press felt. "CD" refers to the cross-machine direction, or the direction orthogonal to the machine direction in the plane of the fabric. The term "PS" refers to the paper side surface of the fabric, which is the surface on which paper products are carried through the paper machine. "MS" refers to the machine side of the fabric and is the surface opposite to the PS. Unless otherwise indicated, the term "yams" or "yams" refers to a continuous length of a single or cabled polymer monofilament such as would be used in the production of a base fabric, and the term "fiber" or "fibers" refers to a relatively small diameter polymer material, such as is commonly used in batt or scrim materials, which has a very small dtex (mass in grams per 10,000 meters of fiber). The terms "left", "right", "upper", and "lower" are used with reference to the accompanying drawings and have the meanings normally ascribed thereto. Unless otherwise indicated, the term "about" means + / - 10% of the value indicated. Reference to a "true direction" (such as "true MD direction") means within + / - 1% of the actual direction indicated. Additional definitions of terms used herein are as follows:

[0075] Additional definitions:

[0076] "Pressed Felt Base Fabric" or "Base Fabric": A woven or nonwoven assembly of yarns provided as an endless structure or continuous loop comprising two overlapping layers (when laid flat) joined at two opposing fold regions comprising continuous MD yarns that shuttle between the folds. The assembly may take the form of: a) an endless woven structure, b) a modified endless woven structure, c) a flat woven fabric folded at two locations to provide a two-layer assembly, d) a fabric formed according to a multiaxial assembly process, or e) a multiaxial or non-multiaxial nonwoven structure assembled to provide any of the foregoing assemblies. The present invention is applicable to all of the above, but the invention is particularly useful in both woven and nonwoven multiaxial base fabric constructions. All base fabrics are post-treated to provide seaming loops formed by return bend regions of the MD oriented component yarns to join the fabric and thereby render the fabric endless. These base fabrics, while providing a durable support for the batt fibers, provide the finished press felt with the necessary physical properties (strength, void volume, resiliency) to survive the rigors of the machine environment in which it will be used.

[0077] Referring to Figures 1 to 4, one construction of a press felt base fabric 30 according to the prior art is shown, in this case a multiaxial construction. Figure 1 shows a strip of material, which may be woven or nonwoven and contains MD oriented yarns 12 and CD oriented yarns 16, being unwound from a source 20 and wound around two rollers 22, 24. The longitudinal edges of the strip are joined together to form a fabric tube. Figure 2 shows the fabric tube folded to form a press felt base fabric 30 having two folded areas 32, 34 defining fabric ends 36, 38. As shown in Figure 3, the continuous MD yarns in the MD yarns 12 form loops 14 at each of the folded areas 32, 34 at the fabric ends 36, 38 that can be nested in a known manner to form a pivot channel 19 into which the pivot 18 is inserted, as shown in Figure 4, thereby forming an endless base fabric 30.

[0078] In the case of the multi-axial pressed felt base fabric 30 and other double layer base fabrics, the double layers formed are joined together by flattening the fabric tube during a needling process in which one or more layers of nonwoven fiber batt material are attached to the base fabric 30 to form the pressed felt.

[0079] Referring to Figures 5 to 10, a further embodiment of a multiaxial pressed felt base fabric 30 is shown. Here again, the base fabric 30 is made from a fabric strip 10; however, the fabric strip 10 includes two systems of MD yarns 12a, 12b provided in a superimposed arrangement, as shown in Figure 6. The two systems of MD yarns 12a, 12b are connected together by a system of CD oriented yarns 16, and as shown in Figure 5, based on the multiaxial construction of the spirally wound base fabric 30, the two systems of MD yarns 12a, 12b are arranged at an oblique angle to the true MD. As shown in Figures 5 and 6, a portion of the lower system of CD oriented yarns 16 and MD yarns 12b is removed in the seam area 40. As shown in Figure 5, this results in an uneven end of the CD oriented yarns 16 at the edge of the seam area 40.

[0080] As shown in FIG. 7 , and as described above in a manner similar to FIGS. 2 to 4 , the fabric tube is folded to form a press felt base fabric 30 having two folded regions 32, 34 defining fabric ends. These folded regions have seam loops 14 formed by return bends of continuous MD yarns 12a in the MD yarns 12a of the upper (now outer) system of MD yarns 12a. These seam loops 14 fit over one another in a known manner to form pivot channels 19 into which pivots 18 are inserted, thereby forming an endless base fabric 30.

[0081] As shown in FIG. 8, to form a prior art press felt, one or more layers of nonwoven fibrous batt material are attached to a base fabric 30 via a needling process.

[0082] As shown in Figure 9, as tensile loads are applied to the press fabric in use, elongation of the seam loop can occur, resulting in seam marking on the paper sheet that the press felt is carrying and premature failure of the press felt.

[0083] Figure 10 is an end view of a prior art base fabric showing seaming loops 14 which are also at an inclined angle relative to the true horizontal plane defined by the press felt due to the multi-axial spiral wound construction of base fabric 30. This also makes seaming of known multi-axial presses more difficult when the press felt is installed on a paper machine.

[0084] Now refer to Figures 11 to 14 , shows a first embodiment of a seamed pressed felt 100 made from a base fabric 130 in accordance with the present invention. The base fabric 130 is provided in the form of a tube having an MD length and a CD width formed from a spirally wound strip of material 110 having a width less than the CD width of the base fabric 130, and contains MD oriented yarns, in this case shown as a first and second system of MD yarns 112a, 112b, which are superimposed on one another and held in place by an additional fabric material component 116. In this embodiment, the additional fabric material component 116 is an interlaced system of CD yarns 116.

[0085] In particular, Fig.13 As shown, when the tube is flattened, the MD oriented yarns 112a of the first yarn system are arranged in overlapping layers in the base fabric 130, and the overlapping layers are connected by the return bends of the MD oriented yarns 112a at the CD oriented fold regions 132, 134 at each of the two opposite ends of the base fabric. Fig.11 and Fig.12 As shown, where the base fabric 130 is shown flat in what will become the CD oriented fold regions 132 , 134 , additional fabric material components 116 are removed from the MD oriented yarns 112a of the first MD yarn system in the CD oriented fold regions 132 , 134 to form seam regions 138 . Fig.11 and Fig.12 The seam area 138 at one end of the fabric is shown, and when the two ends of the base fabric 130 are joined together, Fig.13 In addition to removing the additional fabric material component 116 in the seam area 138, Figures 11 to 14 In the case of the seamed press felt 100 embodiment in , the lower (or inner) second system of MD oriented yarns 112b is also removed by cutting in the seam area 138.

[0086] According to the present invention, Fig.11 and Fig.12As shown, each CD yarn 142 is interwoven across the CD width of the base fabric 130 with the MD oriented yarns 112a in the first MD oriented yarn system, which are in each of the overlapping layers in the CD oriented fold regions 132, 134, forming a seam loop 114 (such as Fig.13 The seam loops 114 are formed by the return bends of the MD oriented yarns 112a in the first MD oriented yarn system at the CD fold regions 132, 134, at each woven region 143 adjacent to each other (as shown). These woven regions 143 anchor the MD oriented yarns 112a in the first MD oriented yarn system at the CD oriented fold regions 132, 134, so that the seam loops 114 are uniformly formed across the CD width of the press felt 100. This is Fig.14 and also from Fig.11 Obviously, Fig.11 MD oriented yarns 112a are shown arranged in true MD and also aligned vertically at the seam with the horizontal plane of the seamed press felt 100. This is in contrast to the prior art where, as is apparent from Figures 5 and 10, MD oriented seam loops 14 are inclined relative to true vertical and arranged obliquely relative to the true MD.

[0087] Reference Fig.13 , a pivot channel 119 is defined by fitting the seam ring 114 from two opposite ends, and the pivot 118 extends through the pivot channel 119 to form a seam.

[0088] like Fig.11 and Fig.14 As shown, preferably, woven region 143 includes a crimp interchange of CD yarns 142 with MD oriented yarns 112a of the first yarn system that is greater than the remainder of base fabric 130, and more preferably twice as much (ie, woven in a plain weave).

[0089] Although Figures 11 to 14 The spiral circular strip of material 110 in the illustrated embodiment of the seamed pressed felt 100 is formed of a woven material, but it may also be formed of a joined nonwoven material, as discussed in further detail below.

[0090] Using the construction of the present invention, the seam area 140 is oriented at 90 degrees to the machine direction of the press felt, and the MD yarns 112a of the first MD oriented yarn system are maintained at a true 90 degrees to the seam area 140 and are oriented in the true machine direction, which results in the fabric being easier to seam and less deformation of the seam loops 114 because they are held in the true machine direction by the CD yarns 142 in the woven area 143.

[0091] In a preferred arrangement, the diameter of the CD yarns 142 in the woven area 143 is selected to maintain a consistent caliper between the body of the press felt 100 and the seam area 138. In a preferred arrangement, the diameter of the CD yarns 142 is + / - 20% of the diameter of the CD yarns used to form the additional textile material component 116 of the woven tape 110. For non-woven additional textile material components 116, the dimensions may vary depending on the configuration of the additional textile material component 116.

[0092] Still refer to Figures 11 to 14 Optionally, at least some of the woven regions 143 may include bicomponent at least partially fusible CD yarns 147 adjacent to where the woven regions 143 interface with the additional fabric material component 116 and the CD oriented fold regions 132, 134. This helps to bond the cut ends of the additional fabric material component 116, which in this embodiment is a CD yarn, in this intersection region during heat treatment. Although this Fig.13 It is only illustrated on the surface of the outer support paper of the press felt 100, but it can also be applied at the inner machine support surface.

[0093] Alternatively, if Fig.40 As shown, instead of the bicomponent at least partially fusible CD yarns 147, a scrim or tape 148 (preferably also made of a bicomponent at least partially fusible polymeric material) may also be used in this zone, which during heat treatment will again serve to bind the cut ends of the additional fabric material component 116 (in this embodiment, the cut CD yarn ends) together to the woven area 143.

[0094] Still refer to Figures 11 to 13 In a preferred embodiment, the woven regions 143 may each include at least one filling yarn 144, which is located adjacent to the seam loops 114 formed by the MD oriented yarns 112 at the CD oriented fold regions 132, 134. These filling yarns 144 are preferably multifilament yarns and are suitable for more firmly anchoring the batt fiber material in the region adjacent to the seam loops 114.

[0095] Although the size of the woven regions 143 may vary depending on the particular application, at least the woven regions 143 each include at least two monofilament yarns 142 interwoven with the MD oriented yarns 112a of the first MD oriented yarn system.

[0096] like Fig.13 As schematically shown in FIG. 1 , batt layer 150 is needle stitched to base fabric 130 and woven region 143 to form press felt 100 .

[0097] Referring now to FIGS. 15 to 21 , a further prior art base fabric 30 ′ for a press felt is shown. The base fabric 30 ′ is similar to the base fabric 30 discussed above. However, in this case, the fabric strip 10 ′ used to form the multiaxially wound base fabric 30 ′ is formed as a nonwoven structure comprising MD oriented yarns 12 joined to first and second layers of CD oriented yarns 16 a, 16 b. The structure of the base fabric 30 ′ is otherwise similar in that an additional fabric material component in the form of two CD oriented yarn systems 16 a, 16 b is removed in a seam region 40 so that when the tube of base fabric material is folded to form two overlapping layers, seam loops 14 are formed by the MD yarns 12 in the region of opposing folded areas 32, 34. Again, as shown in FIG. 19 , the fiber batt material 50 is needled on one or both sides to form the press felt. As shown in FIGS. 20 and 21 , the seam is also subjected to elongation (as shown in FIG. 20 ) resulting in marking of the paper web carried on the paper side surface of the press felt. Further due to the spirally wound configuration, seaming loops 14 are inclined relative to a true vertical line defined by a horizontal plane defined by base fabric 30', as shown in FIG. 21, making seaming more difficult.

[0098] Now refer to Figure 22 to Figure 27 , shows a second embodiment of a seamed pressed felt 100' according to the present invention. The second embodiment of the seamed pressed felt 100' is similar to the first embodiment of the seamed pressed felt 100, except that the base fabric 130' is formed from a single system of MD oriented yarns 112 and first and second systems of CD oriented yarns 116a, 116b as additional fabric material components that hold the MD oriented yarns 112 in place. In this case, the first and second systems of CD oriented yarns 116a, 116b are joined to the MD oriented yarns 112 during the formation of the fabric strip 110', which is spirally wound to form the base fabric 130'. Additional materials such as a bonding scrim (not shown) may be used to join the base fabric 130' together.

[0099] like Fig. 22As shown, the first and second systems of CD oriented yarns 116a, 116b are removed to form seam areas 138 at opposing CD oriented fold regions 132, 134 at each end of the base fabric 130'. Individual CD yarns 142 are interwoven across the CD width of the base fabric 130' with the MD oriented yarns 112 in each of the two overlapping layers in the CD oriented fold regions 132, 134 to form individual woven areas 143, each woven area 143 being located adjacent to the seam loops 114 formed by the return bend regions of the MD oriented yarns 112 at the CD oriented fold regions 132, 134. In this embodiment, filler yarns 144 are also disposed adjacent to the seam loops 114 and are interwoven simultaneously with the individual CD yarns 142 prior to folding the spirally wound tube of material to form the base fabric 130' having two opposing ends forming the CD oriented fold regions 132, 134.

[0100] Furthermore, here, if Figure 24 to Figure 26 As shown in detail, these woven areas 143 anchor the MD oriented yarns 112 at the CD oriented fold areas 132, 134 so that the seam loops 114 are uniformly formed across the CD width of the press felt 100' and are oriented perpendicular to the horizontal surface defined by the surface of the press felt 100', which is uniformly spaced and not tilted when viewed at the surface of the base fabric 130' due to the spirally wound configuration of the base fabric 130'. The woven areas 143 formed by the individual CD yarns 142 interlaced across the seam width of the base fabric 130' ensure that the seam loops 114 extending in the true MD direction are so uniformly formed.

[0101] like Fig.26 As shown, the fiber batt 150 may be stitched through the base fabric 130' with batt fibers 152, which are schematically shown in FIG. Fig.26 in and through the base fabric 130'.

[0102] Referring now to FIGS. 28 to 31 , a further embodiment of a prior art base fabric 30" is shown. Here, the base fabric 30" is formed from a plain woven material strip 10" which includes a system of MD oriented yarns 12 woven with a system of CD oriented yarns 16. The construction of the base fabric 30" is similar to that of the base fabric 30 discussed above, and like elements are assigned the same element numbers. As shown in FIG. 31 , due to the spirally wound construction of the base fabric 30", this arrangement still results in the seam loops 14 being tilted, as shown in FIG. 31 .

[0103] Now refer to Figure 32 to Figure 35 , for example Fig.34A third embodiment of a seamed press felt 100" is shown formed using a base fabric 130". The seamed press felt 100" is similar to the seamed press felt 100 discussed above. However, in this case, the base fabric 130" is formed from a spirally wound strip of material 110", which is a plain woven material including MD oriented yarns 112 and CD oriented yarns 116 as additional fabric material components. Similar to the prior art constructions of the seamed press felt 100, 100' discussed above, this embodiment is similarly formed using CD yarns 142 that are interwoven across the entire CD width of the base fabric 130" with the MD oriented yarns 112 in the seam areas 138 where additional fabric material components (in the form of CD oriented yarns 116) have been removed to form various woven areas 143 adjacent to the seam loops 114. These woven areas 143 anchor the MD oriented yarns 112 at the CD oriented fold areas 132, 134 such that the seam loops 114 are uniformly formed across the CD width of the press felt. Fig.32 and Fig.35 As shown, the seaming loops 114 extend in the true MD direction, and compared to the prior art base fabric 30 ″ shown in FIGS. 28 to 31 , the seaming loops 114 are perpendicular to the horizontal surface defined by the base fabric 130 ″ and extend in the true MD.

[0104] In each of the base fabrics 130, 130', 130", the woven area 143 preferably has CD yarns 142 woven with the MD oriented yarns 112, 112a in a plain weave. The plain weave buckling provides improved anchoring of the MD filaments to the CD filaments and improved anchoring of the batt fibers 152 of the fiber batt 150 to the woven seam base, thereby enhancing stability. This arrangement also further stabilizes the seam loops 114 to reduce loop stretch.

[0105] In addition, to facilitate manufacturing, Fig.41 As shown, the woven area 143 for each of the individual CD fold regions 132, 132 can optionally be woven in one continuous weaving process with spacer yarns 149 that are woven with the CD oriented yarns 116 in the area defining the seam area 140. These spacer yarns 149 are then removed before or after the fabric tube is folded to form the base fabric 130". Similarly, this applies to the base fabrics 130, 130' described above.

[0106] Now refer to Fig.36 and Fig.37, two additional views showing a press felt 100 according to the first embodiment of the present invention as described above are shown. In addition to the above construction, optionally applied anchor yarns 146 are shown, which are sewn through the woven area 143 to anchor the seam loops 114 in place in the base fabric 130. These anchor yarns 146 are sewn in place and overlap the ends of the additional fabric material component, which in this embodiment is the CD oriented yarn system 116 in the base fabric 130.

[0107] Now refer to Fig.38 and Fig.39 , shows a similar arrangement for press felt 100', which uses an optional anchor yarn 146 sewn through the woven area 143 and the end of the additional fabric material component (in this embodiment, the CD oriented yarn system 116a, 116b in the base fabric 130'). The function here is similar to fixing the seam loop 114 in place.

[0108] Anchor yarns may be similarly used for base fabric 130".

[0109] Now refer to Fig.40 , showing the press felt 100 Fig.13 Similar additional views. Here, strips of material 148 are used to connect woven region 143 to the end of the base fabric structure of base fabric 130 from which additional fabric material components (here in the form of CD yarn system 116) have not been removed. Strips of material 148 can be formed from an at least partially fusible scrim, similar to the at least partially fusible CD yarn 147 discussed above, which melts at the heat setting temperature of press felt 100, 100', 100". Although strips of material 148 are shown as only partially overlapping woven region 143 (where in use will be the paper support surface of press felt 100), they can completely overlap woven region 143 and can also be applied to the machine side of press felt 100, thereby also partially or completely overlapping woven region 143 here. Strips of material 148 can optionally also be used on base fabrics 130' and 130".

[0110] Now refer to Fig.42 The method of manufacturing the seamed pressed felt 100 , 100 ′, 100 ″ will be explained in further detail with respect to the flow chart 80 .

[0111] As shown in box 82, the method includes providing a base fabric 130, 130', 130", which is formed into a tube and has an MD length and a CD width, formed by a spirally wound material strip 110, 110', 110" having a width less than the CD width of the base fabric 130, 130', 130", and including at least one system of MD oriented yarns 112, 112a, 112b fixed in place by an additional fabric material component (which can be, for example, a system of CD oriented yarns 116, 116a, 116b, or any other suitable nonwoven component, such as, a suitable nonwoven scrim). The spirally wound material strip 110, 110', 110" can be woven or nonwoven.

[0112] As indicated at block 84 , the method further includes removing additional textile material components 116 , 116a , 116b from the MD oriented yarns 112 , 112a , 112b in the CD oriented fold regions 132 , 134 at opposite MD ends of the tube to form respective seam regions 138 .

[0113] As shown in box 86, the method further includes interweaving each CD yarn 142 across the CD width of the base fabric 130, 130', 130" with the MD oriented yarns 112, 112a in the seam area 138 to form each woven area 143, and in the finished seamed pressed felt 100, 100', 100", each woven area 143 is suitable for being located adjacent to the seam loop 114 formed by the return area of ​​the MD oriented yarn 112, 112a at each of the CD fold areas 132, 134.

[0114] As indicated at block 88 , the method optionally includes interweaving the spacer yarns 149 with the MD oriented yarns 112 , 112a in the seam loop forming region 140 between the woven regions 143 at each of the CD fold regions 132 , 134 .

[0115] As shown in box 90, the method may then further include folding the tube so that the MD oriented yarns 112, 112a in the base fabric 130, 130', 130" are arranged as two overlapping layers connected by the bending areas of the MD oriented yarns 112, 112a, and the bending areas form seam loops 114 at the seam areas 140 at two opposite ends defined by the folding areas 132, 134.

[0116] As indicated at block 92, the method further includes removing spacer yarns 149, if present, from the MD oriented yarns 112, 112a at the seaming loop forming region 140 such that the seaming loops 114 are uniformly formed across the CD width of the press felt 100, 100', 100".

[0117] Furthermore, as shown at block 94, to form the press felt 100, 100', 100", the pivot 118 is inserted through a pivot passage 119 defined by the seam loops 114 from two opposing ends defined by the CD fold regions 132, 134 being nested together to form a seam.

[0118] The method may optionally include stabilizing the woven region 143 by interlacing the bicomponent at least partially fusible CD yarns 147 adjacent to the additional fabric material components 116, 116a, 116b that border the woven region 143 at the CD oriented fold regions 132, 134. The method may then further include at least partially melting the bicomponent at least partially fusible CD yarns 147 to anchor the woven region 143 to the additional fabric material components 116, 116a, 116b that border the woven region 143 at the CD oriented fold regions 132, 134.

[0119] Furthermore, the method may also optionally include stabilizing the woven region 143 using a strip of material 148, which may be, for example, an at least partially fusible scrim.

[0120] Additionally and / or alternatively, the method may further include stabilizing woven region 143 using a heat activated adhesive layer, which may be placed similarly to strips of material 148, as described above.

[0121] Additionally, the method preferably includes needling a fiber batt 150 to the base fabric 130, 130', 130" and the woven region 143 at each of the CD fold regions 132, 134 to provide a uniform surface to the press felt 100, 100', 100" (including across the seam regions).

[0122] According to the present invention, the interweaving of CD yarns 142 at the woven area 143 adjacent to the seam is completed in the base fabric 130, 130', 130" before the seam loops 114 are formed. The CD yarns 142 interwoven across the CD width of the base fabric 130, 130', 130" preferably include at least one filling yarn 144 as discussed above to enhance batt attachment. In addition, temporary yarns (spacer yarns 149) are also woven at the same time to temporarily maintain the space that will form the seam loops 114 once these spacer yarns 149 are removed. This can be done in the base fabric 130, 130', 130" before folding the fabric loops to achieve the desired spacing. In addition, anchoring can also be done at this time using, for example, sewing yarns 146.

[0123] By weaving these complete seam forming areas 138 into the base fabric 130, 130', 130", a relatively uniform seam is formed even in the spirally wound base fabric 130, 130', 130", wherein the seaming loops 114 extend in the true MD and are also perpendicular to the horizontal plane defined by the base fabric 130, 130', 130". In addition, using these woven areas 143, a buckled seam area can be provided in the non-flexed woven body of the base fabric 130, 130', 130" or in a nonwoven used as a base fabric. This produces a seam area with higher buckle compared to a low-flexed woven body. This enhances the retention of batt fibers in the seam area compared to prior known seams.

[0124] A further benefit of the seam formation of the present invention is that there is no tilt or skew in the weave in the seam area, resulting in uniform seam loops 114 that are not angled not only relative to the true MD, but also relative to a vertical line compared to the horizontal plane of the base fabric 130, 130', 130". This vertical orientation of the MD yarn loops is achieved by replacing the angled diagonal yarns formed by the spirally wound strips 110, 110', 110" with interlaced true CD direction yarns 142 that force the MD yarns 112, 112a into the true MD direction in these areas.

[0125] This is the result of weaving a non-multiaxial seam into a multiaxial fabric, achieving the cost saving benefits of a multiaxial fabric while providing the strength and convenience of seaming a traditional woven fabric where the entire fabric is woven into a pressed felt of true CD width.

[0126] A further benefit of the present invention is the resistance of the seam loops 114 to tensile stretching based on their true orientation in the MD, whereas prior known multiaxial press felts typically have seam loops oriented about 85° to 95° to the cross direction defined by the seam due to the spiral winding of the MD yarns.

[0127] Thus, having described the present invention in detail, it should be understood and apparent to those skilled in the art that many physical changes (some of which are only exemplified in the specific embodiments of the present invention) can be made without changing the inventive concepts and principles specifically implemented therein. It should also be understood that a large number of embodiments that incorporate only a portion of the preferred embodiment are possible without changing the inventive concepts and principles specifically implemented therein. Therefore, the present embodiment and optional configurations are actually considered to be exemplary and / or illustrative rather than restrictive, and the scope of the present invention is not represented by the foregoing description but by the appended claims, and therefore, all alternative embodiments and changes to the embodiments that fall within the equivalent meaning and scope of the claims are covered within the scope of the present invention.

Claims

1. A seamed press felt comprising: a base fabric having an MD length and a CD width and comprising at least MD oriented yarns held in place by an additional fabric material component, the MD oriented yarns being arranged in the base fabric as two overlapping layers, the two overlapping layers being joined by return bend regions of the MD oriented yarns at CD oriented fold regions at each of two opposite ends of the base fabric, the additional fabric material component being removed from the MD oriented yarns in the CD oriented fold regions to form a seam region, each CD yarn interweaving across the CD width of the base fabric with the MD oriented yarn in each of the overlapping layers in the CD oriented fold regions forming each woven region, the each woven region being located adjacent to a seaming loop formed by the return turn regions of the MD oriented yarns at the CD fold regions, the woven region anchoring the MD oriented yarns at the CD oriented fold regions so that the seaming loops are formed uniformly across the CD width of the press felt, and A pivot extends from the two opposite ends through a passage defined by the interfitting of the seaming rings to form a seam.

2. The seamed pressed felt according to claim 1, wherein: The woven region includes a two-fold buckling interlacing of the CD yarns with the MD oriented yarns.

3. The seamed pressed felt according to claim 1, wherein: The base fabric includes a helically wound strip of material having a width less than the CD width of the base fabric.

4. The seamed pressed felt according to claim 3, wherein: The spirally wound strip of material comprises a joined nonwoven material.

5. The seamed pressed felt according to claim 3, wherein: The helically wound strip of material comprises a woven material.

6. The seamed pressed felt according to claim 3, wherein: The woven region anchors the MD oriented yarns at the CD oriented fold regions such that the seaming loops extend in the true machine direction of the base fabric.

7. The seamed pressed felt according to claim 1, wherein: The seam region is oriented at 90 degrees to the machine direction of the press felt.

8. The seamed press felt according to claim 1, wherein: The diameter of the CD yarns in the woven area is selected to maintain a consistent caliper between the body of the press felt and the seam area.

9. The seamed pressed felt according to claim 1, wherein: At least some of said woven regions contain bicomponent at least partially fusible CD yarns adjacent said additional textile material component bordering said woven regions at said CD oriented fold regions.

10. The seamed pressed felt according to claim 1, wherein: The woven regions each contain at least one fill yarn located adjacent the seaming loops formed by the MD oriented yarns at the CD fold regions.

11. The seamed pressed felt according to claim 10, wherein: The at least one filling yarn is a multifilament yarn.

12. The seamed pressed felt according to claim 1, wherein: The woven regions each contain at least two monofilament yarns interwoven with the MD oriented yarns.

13. The seamed press felt of claim 1 further comprising individual strips of facing material connected to the woven regions.

14. The seamed press felt of claim 1 further comprising a batt layer needle stitched to the base fabric and the woven area.

15. A method of making a seamed press felt, comprising: providing a base fabric formed into a tube having an MD length and a CD width formed from a helically wound strip of material having a width less than the CD width of the base fabric and comprising at least MD oriented yarns held in place by an additional fabric material component; removing said additional fabric material component from said MD oriented yarns in said CD oriented fold regions at two opposing MD ends of said tube to form respective seam regions; interweaving respective CD yarns across the CD width of the base fabric with the MD oriented yarns in the seam regions to form respective woven regions adapted to be located adjacent to seam loops in the finished seamed press felt, the seam loops being formed by return bend regions of the MD oriented yarns at each of the CD fold regions; interweaving spacer yarns with said MD oriented yarns in seam loop forming areas between said woven areas at each of said CD fold areas; folding the tube so that the MD oriented yarns in the base fabric are arranged as two overlapping layers connected by the return bend regions of the MD oriented yarns, the return bend regions forming the seaming loops at the seaming regions at the two opposing MD ends; removing the spacer yarns from the MD oriented yarns at the seaming loop forming region so that the seaming loops are formed uniformly across the CD width of the press felt; as well as The pivot shaft is inserted through the passage defined by nesting the seam loops from the two opposing ends to form a seam.

16. The method according to claim 15, further comprising: stabilizing said woven region by interweaving bicomponent at least partially fusible CD yarns adjacent said additional fabric material component bordering said woven region at said CD oriented fold region; and at least partially melting the bicomponent at least partially fusible CD yarns to anchor the woven region to the additional textile material component bordering the woven region at the CD oriented fold region.

17. The method of claim 15, further comprising stabilizing the woven region using an at least partially fusible scrim.

18. The method of claim 15, further comprising stabilizing using a heat activated adhesive layer.

19. The method of claim 15, further comprising stitching a batt to the base fabric and the woven region at each of the CD fold regions.

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