Press fabrics

Abstract

A press fabric for paper manufacture includes three or more layers of machine direction (MD) yarns. The three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. The paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer. The press fabric includes a first system of cross-machine direction (CD) yarns. The CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers. The press fabric includes a second system of CD yarns. The CD yarns of the second system pass outside the paper-side layer and remain inside the machine-side layer.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 747,654, filed on Jan. 21, 2025, the entirety of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to fabrics for paper manufacture.BACKGROUND

[0003] During papermaking processes, after a forming section in which a pulp slurry is formed into a sheet, the sheet is processed in a press section. The sheet is supported by press fabrics (or “felts”) that pass through a series of press nips, typically with increasing load at each nip. The loading of the nips generate a build-up of hydraulic pressure within the sheet, which leads to an expression of water from the sheet into the felt. This mechanical compaction process is known as wet pressing. The press fabric has a “paper side” on which the sheet is supported and a “machine side,” opposite the paper side, in contact with or otherwise adjacent to the machine elements such as rolls.SUMMARY

[0004] Some aspects of this disclosure relate to press fabrics for paper manufacture. For example, described a press fabric for paper manufacture, the press fabric including: three or more layers of machine direction (MD) yarns, wherein the three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. The paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer. The press fabric includes a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers; and a second system of CD yarns, wherein the CD yarns of the second system pass outside the paper-side layer and remain inside the machine-side layer.

[0005] This and other press fabrics described herein can have one or more of at least the following

[0006] In some implementations, the paper-side layer includes: first yarns that are aligned with corresponding yarns of the machine-side layer and the one or more intermediate layers; and second yarns that are offset from yarns of the machine-side layer and the one or more intermediate layers.

[0007] In some implementations, the CD yarns of the second system form knuckles on the paper side of the second yarns.

[0008] In some implementations, the CD yarns of the first system form knuckles on the paper side of the first yarns.

[0009] In some implementations, the first yarns alternate with the second yarns along the cross-machine direction.

[0010] In some implementations, the CD yarns of the second system form knuckles on the paper side of the first yarns.

[0011] In some implementations, the one or more intermediate layers and the machine-side layer include a same number of yarns per unit length along the cross-machine direction.

[0012] In some implementations, the paper-side layer has a 2:1 ratio of yarns per unit length along the cross machine direction with the one or more intermediate layers and with the machine-side layer.

[0013] In some implementations, the paper-side layer has a 2:1 ratio of yarns per unit length along the cross-machine direction with the machine-side layer.

[0014] In some implementations, the CD yarns of the second system separate the paper-side layer from the one or more intermediate layers.

[0015] In some implementations, the CD yarns of the second system include separation yarns with a binding force toward the paper side.

[0016] In some implementations, the CD yarns of the second system form a single-layer sequence.

[0017] In some implementations, the CD yarns of the second system, while extending continuously adjacent to a layer that is closest to the paper-side layer among the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the layer that is closest to the paper-side layer.

[0018] In some implementations, the CD yarns of the second system, while extending continuously between the paper-side layer and a layer that is closest to the paper-side layer among the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the paper-side layer.

[0019] In some implementations, the CD yarns of the second system remain toward the paper side of the one or more intermediate layers.

[0020] In some implementations, the CD yarns of the second system form knuckles on the paper side of yarns of the paper-side layer.

[0021] In some implementations, the press fabric includes a third system of CD yarns. The CD yarns of the third system extend between the machine-side layer and the one or more intermediate layers and remain inside the machine-side layer.

[0022] In some implementations, the CD yarns of the third system bind, toward the paper side, a layer that is closest to the machine-side layer among the one or more intermediate layers.

[0023] In some implementations, the CD yarns of the third system, while extending continuously between the machine-side layer and a layer that is closest to the machine-side layer among the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the machine-side layer.

[0024] In some implementations, the CD yarns of the third system extend between the paper-side layer and the one or more intermediate layers.

[0025] In some implementations, the CD yarns of the third system pass outside the paper-side layer.

[0026] In some implementations, the CD yarns of the third system remain inside the paper-side layer.

[0027] In some implementations, the CD yarns of the third system form a single-layer sequence.

[0028] In some implementations, the CD yarns of the third system form a double-layer sequence.

[0029] In some implementations, a permeability of the machine-side layer is higher than a permeability of the paper-side layer.

[0030] In some implementations, the one or more intermediate layers include a plurality of intermediate layers, and the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system extend between two intermediate layers of the plurality of intermediate layers, and wherein the CD yarns of the third system remain inside the paper-side layer and the machine-side layer.

[0031] In some implementations, the CD yarns of the third system form a double-layer sequence that separates the two intermediate layers from one another with a binding force toward the paper side.

[0032] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, the CD yarns of the second system include separation yarns with a binding force toward the paper side, and the press fabric of includes a third system of CD yarns, wherein the CD yarns of the third system include separation yarns with a binding force toward the machine side.

[0033] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers. The CD yarns of the second system form knuckles on the paper side of yarns of the paper-side layer, and the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system form knuckles on the machine side of yarns of the machine-side layer.

[0034] In some implementations, the CD yarns of the first system bind the paper-side layer together with the first intermediate layer of the one or more intermediate layers, and the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system bind the machine-side layer together with the first intermediate layer or a second intermediate layer of the one or more intermediate layers.

[0035] In some implementations, the CD yarns of the second system, while extending continuously adjacent to a layer of the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the layer.

[0036] In some implementations, the press fabric includes a third system of CD yarns. The CD yarns of the third system pass outside the machine-side layer and remain inside the paper-side layer.

[0037] In some implementations, the CD yarns of the third system extend between the paper-side layer and the one or more intermediate layers.

[0038] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, and wherein the CD yarns of the third system extend between two intermediate layers of the plurality of intermediate layers.

[0039] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, and the CD yarns of the first system remain toward a paper side of a layer that is closest to the machine-side layer among the plurality of intermediate layers.

[0040] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, the first intermediate layer has a same number of yarns per unit length along the cross-machine direction as the paper-side layer, a second intermediate layer of the plurality of intermediate layers has a same number of yarns per unit length along the cross-machine direction as the machine-side layer, and the second intermediate layer is closer to the machine-side layer than is the first intermediate layer.

[0041] In some implementations, MD yarns of two layers of the machine-side layer and the one or more intermediate layers form seam loops, and the press fabric includes: first CD yarns woven in the paper-side layer and arranged over the seam loops, and second CD yarns woven in the seam loops.

[0042] In some implementations, the first CD yarns and the second CD yarns include texturized yarns.

[0043] In some implementations, the first CD yarns are woven in a flap area that extends over the seam loops.

[0044] In some implementations, the first CD yarns and the second CD yarns are closer to the seam loops than are the first system of CD yarns and the second system of CD yarns.

[0045] In some implementations, the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system are straight yarns that extend between the paper-side layer and the one or more intermediate layers, between two intermediate layers of the one or more intermediate layers, or between the one or more intermediate layers and the paper-side layer.

[0046] In some implementations, the press fabric includes one or more layers of batt attached to at least one of the paper-side layer or the machine-side layer.

[0047] Some aspects of this disclosure describe another press fabric for paper manufacture. The press fabric includes: three or more layers of machine direction (MD) yarns, wherein the three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. The paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer. The press fabric includes a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers; and a second system of CD yarns, wherein the CD yarns of the second system separate the paper-side layer from the one or more intermediate layers.

[0048] This and other press fabrics described herein can have one or more of at least the following characteristics.

[0049] In some implementations, the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system separate the machine-side layer from the one or more intermediate layers.

[0050] In some implementations, the CD yarns of the second system bind toward the paper side.

[0051] Some aspects of this disclosure described another press fabric for paper manufacture. The press fabric includes: a paper-side layer of machine direction (MD) yarns at a paper side of the press fabric; a machine-side layer of MD yarns at a machine side of the press fabric, wherein the paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer; a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer and the machine-side layer together; and a second system of CD yarns, wherein the CD yarns of the second system separate the paper-side layer from the machine-side layer.

[0052] This and other press fabrics described herein can have one or more of at least the following characteristics.

[0053] In some implementations, the CD yarns of the second system remain inside the machine-side layer.

[0054] In some implementations, the press fabric is a two-layer press fabric.

[0055] Some aspects of this disclosure described another press fabric for paper manufacture. The press fabric includes: three or more layers of machine direction (MD) yarns, wherein the three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. MD yarns of two layers of the machine-side layer and the one or more intermediate layers form seam loops. The press fabric includes cross-machine direction (CD) yarns, wherein the CD yarns include first CD yarns woven in the paper-side layer and arranged over the seam loops, and second CD yarns woven in the seam loops.

[0056] This and other press fabrics described herein can have one or more of at least the following characteristics.

[0057] In some implementations, the first CD yarns and the second CD yarns include texturized yarns.

[0058] In some implementations, the press fabric includes a first system of CD yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers. The CD yarns of the first system have a different composition from the first CD yarns and the second CD yarns.

[0059] In some implementations, the first CD yarns and the second CD yarns are closer to the seam loops than are the first system of CD yarns.

[0060] The details of one or more implementations of the subject matter of this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIGS. 1A-1C are side sectional and perspective sectional views of an example of a two-layer press fabric.

[0062] FIGS. 2A-2C are side sectional and perspective sectional views of another example of a two-layer press fabric.

[0063] FIGS. 3A-3C are side sectional and perspective sectional views of another example of a two-layer press fabric.

[0064] FIGS. 4A-4C are side sectional and perspective sectional views of an example of a three-layer press fabric.

[0065] FIGS. 5A-5C are side sectional and perspective sectional views of another example of a three-layer press fabric.

[0066] FIGS. 6A-6C are side sectional and perspective sectional views of another example of a three-layer press fabric.

[0067] FIGS. 7A-7C are side sectional and perspective sectional views of another example of a three-layer press fabric.

[0068] FIGS. 8A-8F are side sectional, top, bottom, perspective, and two side sectional views of an example of a four-layer press fabric.

[0069] FIG. 9 is a side-sectional view of an example of a three-layer press fabric.

[0070] FIGS. 10-13 are side-sectional views of examples of four-layer press fabrics.

[0071] FIGS. 14-18 are side-sectional views of examples of three-layer press fabrics.

[0072] FIGS. 19, 23, and 24 are perspective, side, and top views, respectively, of an example of a press fabric including additional CD yarns.

[0073] FIGS. 20, 25, and 26 are perspective, top, and bottom views, respectively, of an example of a press fabric including additional CD yarns.

[0074] FIGS. 21 and 22 are side-view and top-view photographs, respectively, of an example of a press fabric including additional CD yarns.

[0075] FIG. 27 is a side-sectional view of an example of a two-layer press fabric.

[0076] FIG. 28 is a side-sectional view of an example of a three-layer press fabric.DETAILED DESCRIPTION

[0077] Various aspects of this disclosure describe fabrics and weave patterns for use in papermaking, e.g., as press fabrics. In some implementations, the disclosed fabrics can exhibit high void volume, openness, and binding characteristics that improve water removal from paper sheets and water transfer out of the fabrics themselves.

[0078] During the press section of a papermaking process, the efficacy of water removal from the paper sheet depends in large part on the characteristics of the press fabric. For example, fabrics with higher void volume (the open volume within the fabric that is not occupied by yarns / fibers) may be able to remove more water, as the voids provide space for water storage, thereby improving dewatering / water removal for the paper sheet. Layers of the press fabric with higher permeability / openness can also promote water removal. For example, when layers further from the paper sheet (e.g., a layer opposite the paper sheet) have higher permeability / openness, water can be transferred out of the press fabric through those layers, allowing more water to be absorbed from the paper side of the press fabric. At the same time, fabrics should have sufficient strength and resilience to remain stable under the high pressure exerted by the rolls. Weave characteristics of the fabric can also determine the drainability of the fabric, e.g., how easily water transferred from the paper sheet to the fabric can be removed from the fabric to facilitate further subsequent absorption by the fabric and improve dewatering of the paper sheet.

[0079] Some implementations according to this disclosure provide multi-layer press fabrics with high void volume and / or permeability at the machine side, e.g., higher openness at the machine side than at the paper side. This configuration can facilitate rapid water removal from sheets without compromising the fabrics'ability to support paper sheets. In some implementations, the press fabrics have higher yarn densities at the paper side than at the machine side (e.g., based on yarn counts in machine-direction layers, weave patterns of cross-machine direction separation layers / yarns, and / or binding directions of cross-machine direction separation layers / yarns), to improve water transfer out of the paper sheet and out of the press fabric. In some implementations, improved dewatering can be provided through configurations of “separation yarns” provided as cross-machine direction yarns in the press fabrics.

[0080] FIGS. 1A-1C illustrate an example of a two-layer press fabric 100 according to some implementations of the present disclosure. FIG. 1A is a side sectional view facing along a machine direction (MD), FIG. 1B is a side sectional view facing along a cross-machine direction (CD) axis from the left-most edge of FIG. 1A, and FIG. 1C is a perspective sectional view.

[0081] The press fabric 100 includes a paper-side layer (or top layer) 102-1 on which a paper sheet is placed for pressing, and a machine-side layer (or bottom layer) 102-2 opposite the paper-side layer. All side sectional views of press fabrics herein have this orientation. The paper-side layer 102-1 and the machine-side layer 102-2 are stacked on one another and include a series of threads or yarns extending parallel to one another in a machine direction (MD). Because these yarns extend in the machine direction, the yarns can be referred to as “MD yarns,” and the layers 102-1, 102-2 can be referred to as “MD layers”102. Consistent with standard terminology in the field, “machine direction” and “cross-machine direction” as used herein are with respect to the papermaking rolls with which the fabrics are used, e.g., which may not correspond to a machine direction and cross-machine direction with which the fabrics are weaved.

[0082] It will be understood that a “layer” as described herein, while being defined with respect to a certain set of MD yarns, can include CD yarns, for example, performing a binding and / or separation function on the MD yarns, and / or otherwise extending through or amongst the MD yarns of the layer. The presence of the CD yarns in MD layers is relevant, because the CD yarns partially determine the permeability / openness of the MD layer. For example, an MD layer in which a higher density of CD yarns is present may have a lower permeability than an MD layer in which a lower density of CD yarns is present. That is, the permeability / openness of an MD layer may depend on the CD yarns that are present in the layer, e.g., where more CD yarns may correspond to lower permeability. Some implementations of the weaves discussed herein provide higher permeability / openness in layers of MD yarns (e.g., layers at or near the machine side of the press fabric), at least in part based on the disclosed weave patterns of the CD yarns. As such, references herein to a “layer” of MD yarns do not preclude the presence of other yarns amongst the MD yarns of the layer.

[0083] The paper-side layer 102-1 need not be in direct contact with paper sheets. For example, in some implementations a layer of batt is present between the paper-side layer 102-1 and paper sheets, e.g., needled onto the paper side of the press fabric 100. The press fabrics described herein can constitute a base structure and should not be understood to preclude the presence of other layer(s) / material(s) such as batt. In some implementations, batt is present between the machine-side layer 102-2 and the roll. In some implementations, batt is present between layers of the press fabric 101. Other layers can instead or additionally be present. For example, a coating may be present on the layer of batt and / or between the layer of batt and the paper-side layer 102-1. For example, the press fabric may have a laminate structure including two or more separate weaves attached to one another, optionally with a coating or material (e.g., batt) in-between. One or more of the two or more separate weaves can have a weave structure as described for the press fabrics discussed herein.

[0084] The MD yarns making up the MD layers 102 can include, for example, monofilament, plied monofilament, multifilament, and / or plied multifilament yarn. In some implementations, the MD yarns are polymeric, e.g., polyamide yarns or polyester yarns, or any other suitable yarn. The respective yarns of the layers 102-1, 102-2 can be the same as one another and / or different from one another (e.g., in composition and / or type), and the yarns within each layer 102-1, 102-2 can be the same as one another and / or different from one another.

[0085] The paper-side layer 102-1 has a higher number of yarns per unit length along the cross-machine direction (CD, transverse to the extension direction of the MD layers 102) than the machine-side layer 102-2. For example, as shown in FIGS. 1A-1C, there can be twice as many yarns per unit length in the paper-side layer 102-1 as in the machine-side layer 102-2, for a 2:1 yarn density ratio (or yarn number ratio). In some implementations, as in the press fabric 100, some yarns of the paper-side layer 102-1 are aligned with corresponding yarns of the machine-side layer 102-2, and other yarns of the paper-side layer 102-1 may not be in alignment with a yarn of the machine-side layer 102-2. For example, alternating yarns of the paper-side layer 102-1 can be aligned with (e.g., directly above) corresponding yarns of the machine-side layer 102-2, and the remaining yarns of the paper-side layer 102-1 can be out-of-alignment with the yarns of the machine-side layer 102-2. Other yarn ratios and arrangements are also within the scope of this disclosure. For example, in some implementations, the paper-side layer 102-1 has a 3:1, 4:1, 3:2, or 5:2 yarn density ratio with the machine-side layer 102-2, or any other yarn density ratio greater than 1. These and other ratios are applicable not only to the press fabric 100 but also to other two-layer press fabrics within the scope of this disclosure.

[0086] Based on the difference in yarn counts (or yarn densities), in some implementations, a permeability / openness of the machine-side layer 102-2 is greater than a permeability / openness of the paper-side layer 102-1. For example, where alternating MD yarns are present in the paper-side layer 102-1, the machine-side layer 102-2 has no corresponding yarn; instead, a void is present. The presence of these voids in the machine-side layer 102-2 (or greater permeability or openness of the machine-side layer 102-2) can contribute to overall greater dewatering by the press fabric 100, e.g., because water from the paper side can more easily be transferred towards the machine side to be extracted from the press fabric 100, permitting more water to then be taken in at the paper side. In some implementations, the paper-side layer 102-1, although having a lower permeability than the machine-side layer 102-2, has a high strength corresponding to its increased yarn density. As such, the paper-side layer 102-1 is able to support paper sheets effectively on the paper-side layer 102-1.

[0087] The press fabric 100 also includes CD yarns that bind together the MD yarns and render the yarns a cohesive fabric. In some implementations, two systems of CD yarns are included. A first system of CD yarns includes CD yarns 104. The CD yarns 104 are configured to bind the layers 102-1, 102-2 together. For example, the CD yarns 104 can pass outside the paper-side layer 102-1 (to the paper side of the paper-side layer 102-1) and outside the machine-side layer 102-2 (to the machine side of the machine-side layer 102-2). As such, the CD yarns 104 can exert tension between the paper-side layer 102-1 and the machine-side layer 102-2. In some implementations, the CD yarns 104 cross between yarns (e.g., vertically-aligned yarns) of the paper-side layer 102-1 and the machine-side layer 102-2, respectively. The CD yarns 104 can be woven in a double-layer sequence, meaning that the CD yarns 104 pass outside two adjacent MD layers 102 (the layers 102-1 and 102-2). The CD yarns 104 bind sixth yarn of the paper-side layer 102-1 and every third yarn of the machine-side layer 102-2, forming knuckles 120. Yarns, such as the CD yarns 104, that bind together a paper-side layer and a machine-side layer, can be referred to as “binder yarns” or as constituting / forming a “binder system.”

[0088] A second system of CD yarns includes CD yarns 106. The CD yarns 106 are woven in a single-layer sequence passing outside the paper-side layer 102-1, crossing between the paper-side layer 102-1 and the machine-side layer 102-2, and remaining inside the machine-side layer 102-2 (remaining on a paper side of the machine-side layer 102-2). Because of this weave pattern (e.g., because the CD yarns 106 remain inside the machine-side layer 102-2), the CD yarns 106 permit a high permeability / openness in the machine-side layer 102-2, corresponding to increased dewatering by the press fabric 100.

[0089] The CD yarns 106 are configured to separate the MD layers 102-1, 102-2. For example, the CD yarns 106 can extend adjacent to multiple consecutive yarns of the machine-side layer 102-2, e.g., extend between the MD layers 102-1, 102-2 so as to pass adjacent to multiple consecutive yarns of the machine-side layer 102-2 without passing outside either MD layer 102-1, 102-2 during that extension. This configuration can be referred to as “flotation.” The CD yarns 106 pass outside single yarns of the paper-side layer 102-1, e.g., do not extend outside the paper-side layer 102-1 for multiple consecutive yarns of the paper-side layer 102-1, so as to bind single yarns of the paper-side layer 102-1, forming knuckles 122. Based on this configuration, the CD yarns separate the MD layers 102-1, 102-2 with upward binding (binding toward the paper side), e.g., exerting tension that tends to separate the paper-side layer 102-1 from the machine-side layer 102-2. The paper-side layer 102-1 maintains stability, and the separation of the MD layers 102-1, 102-2 provides stability for the paper-side layer 102-1 and increases the fabric openness, e.g., in the machine-side layer 102-2. As such, the CD yarns 106 maintain the structure of the press fabric 100 while contributing to a high void volume in the press fabric 100 by binding toward the paper side, in association with the lower yarn density toward the machine side as a result of the upward binding direction.

[0090] Yarns that perform a separation function, such as some of the CD yarns included in the press fabrics described herein, can be referred to as “separation yarns” and as constituting a “separation system.” Separation yarns / systems provide support in the press fabric to reduce compaction, thereby increasing the fabric's openness and, correspondingly, dewatering capability. In some cases, to separate two MD layers, a CD yarn can extend laterally between two MD layers, adjacent to multiple consecutive yarns of the MD layers. Separation by the CD yarns causes the MD layers to retain their open, stacked arrangement when pressure is applied, as opposed to collapsing. Further, to provide tension that corresponds to the separation force, a separation yarn can bind a single yarn of an MD layer. For example, referring to labels in FIG. 1C, the separation yarn can cross upward between MD yarn 102-1A and an adjacent second MD yarn 102-1B, pass over (e.g., outside) the second MD yarn 102-1B, and then cross downward between the second MD yarn 102-1B and an adjacent third MD yarn 102-1C. Based on this configuration, the separation yarn can exert an upward binding force (towards the paper side), to (i) separate the MD layers between which the separation yarn extends adjacent to multiple consecutive MD yarns, with (ii) a binding force towards the MD layer around which the separation yarn is woven.

[0091] In some implementations, as shown in FIGS. 1A-1C, the CD yarns 106 bind every sixth yarn of the paper-side layer 102-1 and extend adjacent to two consecutive yarns of the machine-side layer 102-2. However, other weave patterns of the CD yarns 106 are also within the scope of this disclosure, e.g., the CD yarns 106 can pass outside the paper-side layer 102-1 at a different rate and / or extend adjacent to a different number of consecutive yarns of the machine-side layer 102-2.

[0092] In some implementations, as shown in FIGS. 1A-1C, each of the first system of CD yarns 104 and the second system of CD yarns 106 is a three-end sequence. For example, along the machine direction, CD yarns 104 and CD yarns 106 alternate with one another. However, other weave patterns of the CD systems (e.g., number of ends in either or both systems, relative positioning between yarns of the CD systems, and / or the like) are also within the scope of this disclosure.

[0093] The CD yarns 104, 106 can be the same as or different from the MD yarns of the MD layers 102. For example, the CD yarns 104, 106 can include monofilament, plied monofilament, multifilament, and / or plied multifilament yarn. In some implementations, the CD yarns 104, 106 are composed of polyamide or another polymer material. In some implementations, at least some of the CD yarns 104, 106 are composed of a different material from the MD yarns. For example, in some implementations, at least some of the CD yarns 104, 106 are composed of an elastomer such as elastane, polyester, and / or polyurethane, and the MD yarns are composed of a lower-elasticity material such as polyamide. This configuration can cause the press fabric 100 to have a high elasticity, a characteristic that in some cases can provide improved papermaking performance. In some implementations, the weave patterns described herein provide relatively high elasticity, e.g., based on the presence of the separation yarns configured as described herein.

[0094] Accordingly, based on the relative yarn density ratios of the paper-side layer 102-1 and the machine-side layer 102-2, and based on the configuration of the CD yarns 106, the press fabric 100 can provide, in some implementations, improved water extraction and stability. The machine side of the press fabric 100 is relatively “open” so as to facilitate water transfer out of the machine side.

[0095] FIGS. 2A-2C illustrate another example of a press fabric 200. FIG. 2A is a side sectional view facing along the machine direction, FIG. 2B is a diagrammatic representation of the weave of the press fabric 200 facing along the CD axis from the left-most edge of FIG. 2A, and FIG. 2C is a perspective sectional view.

[0096] Like the press fabric 100, the press fabric 200 includes two MD layers 102-1, 102-2 which have characteristics as described for the corresponding layers of FIG. 1. Further, the press fabric 200 includes two systems of CD yarns. First and second systems of CD yarns 204, 206 have characteristics as described for the CD yarns 104, 106 of the press fabric 100, respectively, except as shown or described otherwise herein. For example, the CD yarns 204 of the first system (a double-layer sequence) bind together the paper-side layer 102-1 and the machine-side layer 102-2. The CD yarns 206 of the second system (a single-layer sequence) separate the MD layers 102-1, 102-2 with binding up toward the paper side, pass outside the paper-side layer 102-1, and remain inside the machine-side layer 102-2.

[0097] Whereas the systems of CD yarns 104, 106 of the press fabric 100 include three ends each, the systems of CD yarns 204, 206 of the press fabric 200 include four and two ends, respectively. Along the machine direction, the CD yarns follow a pattern of one CD yarn 206 followed by two CD yarns 204. The CD yarns 204 can bind every eighth yarn of the paper-side layer 102-1 and every fourth yarn of the machine-side layer 102-2, forming knuckles 220. The CD yarns 206 can bind every fourth yarn of the paper-side layer 102-1, forming knuckles 222.

[0098] FIGS. 3A-3C illustrate another example of a press fabric 300. FIG. 3A is a side sectional view facing along the machine direction, FIG. 3B is a diagrammatic representation of the weave of the press fabric 300 facing along the CD axis from the left-most edge of FIG. 3A, and FIG. 3C is a perspective sectional view.

[0099] The press fabric 300 includes two MD layers 102-1, 102-2 which have characteristics as described for the corresponding layers of press fabrics 100 and 200. Further, the press fabric 300 includes two systems of CD yarns. First and second systems of CD yarns 304, 306 have characteristics as described for the CD yarns 104, 106 of the press fabric 100, respectively, except as shown or described otherwise herein. For example, the CD yarns 304 of the first system (a double-layer sequence) bind together the paper-side layer 102-1 and the machine-side layer 102-2. The CD yarns 306 of the second system (a single-layer sequence) separate the MD layers 102-1, 102-2 with binding up toward the paper side, pass outside the paper-side layer 102-1, and remain inside the machine-side layer 102-2.

[0100] Each of the first and second systems of CD yarns 304, 306 is a four-end system. Along the machine direction, the CD yarns alternate between CD yarns 304 and CD yarns 306. The CD yarns 306 of the second system, to separate the MD layers 102-1, 102-2 with binding toward the paper side, extend adjacent to four consecutive yarns of the machine-side layer 102-2 and then pass outside a single yarn of the paper-side layer 102-1. The CD yarns 304 can bind every eighth yarn of the paper-side layer 102-1 and every fourth yarn of the machine-side layer 102-2, forming knuckles 320. The CD yarns 306 can bind every eighth yarn of the paper-side layer 102-1, forming knuckles 322.

[0101] The press fabrics 200 and 300 can provide the advantages discussed for the press fabric 100. For example, because the machine-side layers 102-2 of the press fabrics 200, 300 include fewer yarns than the paper-side layers 102-1, the press fabrics 200, 300 have high permeability toward the machine side while maintaining their strength to support paper sheets on the paper side. In some implementations, the permeability is increased by the separation (with binding toward the paper side) provided by the second systems of CD yarns 206, 306.

[0102] The scope of this disclosure is not limited to two-layer fabrics. In some implementations, the press fabric has three, four, or more layers.

[0103] For example, FIGS. 4A-4C illustrate an example of a press fabric 400 having three layers of MD yarn. FIG. 4A is a side sectional view facing along the machine direction, FIG. 4B is a diagrammatic representation of the weave of the press fabric 400 facing along the CD axis from the left-most edge of FIG. 4A, and FIG. 4C is a perspective sectional view.

[0104] The press fabric 400 includes a paper-side layer 402-1, a machine-side layer 402-3, and an intermediate layer 402-2. In some implementations, a press fabric having four or more layers of MD yarn includes multiple intermediate layers 402-2 stacked on one another between the paper-side layer 402-1 and the machine-side layer 402-3.

[0105] In some implementations, the paper-side layer 402-1 has a higher number of yarns per unit length (a higher yarn density) along the cross-machine direction than the machine-side layer 402-3. For example, the press fabric 400 has a 2:1 yarn density ratio between the paper-side layer 402-1 and the machine-side layer 402-3. Alternating yarns of the paper-side layer 402-1 are aligned with (e.g., disposed above) a corresponding yarn of the machine-side layer 402-3 or are above a position where no yarn of the machine-side layer 402-3 is present (misaligned with the yarns of the machine-side layer 402-3), corresponding to a void. As discussed with respect to the two-layer fabrics of FIGS. 1A to 3C, the lower number of yarns of the machine-side layer 402-3 can provide a higher permeability / openness, corresponding to improved drainage and dewatering by the press fabric 400. Further, as discussed with respect to the two-layer yarns, the density ratio is not limited to 2:1 but rather, in some implementations, can be 3:1, 4:1, 3:2, 5:2, or another density ratio.

[0106] In some implementations, in a fabric having three or more MD layers (e.g., any press fabric, as described herein, having three or more MD layers), at least one of the intermediate layers has fewer yarns per unit length along the cross-machine direction than the paper-side layer. For example, at least one of the intermediate layers (e.g., all intermediate layers) can have a yarn density equal to a yarn density of the machine-side layer. In some implementations, at least one of the intermediate layers has a yarn density less than that of the paper-side layer and more than that of the machine-side layer. For example, yarn density ratios between the paper-side layer, at least one intermediate layer, and the machine-side layer can be 2:1:1, 3:1:1. 3:2:1, 4:1:1, 4:2:1, 3:2:1, etc. As shown in FIGS. 4A and 4C, the intermediate layer 402-2 has a yarn density matching that of the machine-side layer 402-3. Yarns of the intermediate layer 402-2 are aligned with (disposed above) corresponding yarns of the machine-side layer 402-3. Correspondingly, the paper-side layer 402-1 has a 2:1 yarn density ratio with the intermediate layer 402-3. Alternating yarns of the paper-side layer 402-1 are aligned with (e.g., disposed above) a corresponding yarn of the intermediate layer 402-2 or are above a position where no yarn of the intermediate layer 402-2 is present (misaligned with the yarns of the intermediate layer 402-2), corresponding to a void.

[0107] It will be understood that the yarn density relationship between the paper-side layer, the intermediate layer(s), and the machine-side layer is not limited to this example. In some implementations, at least one intermediate layer has a number of yarns per unit length in the cross-machine direction that matches that of the paper-side layer, e.g., has a yarn density ratio of 1:1 with the paper-side layer. Instead, or additionally, at least one intermediate layer can have a number of yarns per unit length in the cross-machine direction that is less than that of the paper-side layer and more than that of the machine-side layer, e.g., has a yarn density ratio of less than 1 with the paper-side layer and more than 1 with the machine-side layer. For example, yarn density ratios between the paper-side layer, at least one intermediate layer, and the machine-side layer can be 2:2:1, 3:2:1, 4:2:1, or 5:3:1, to provide several non-exhaustive examples. When there is more than one intermediate layer, different intermediate layers can have the same or different yarn densities. For example, a first intermediate layer can have a yarn density matching that of the paper-side layer, a second intermediate layer can have a yarn density in-between that of the paper-side layer and that of the machine-side layer, and / or a third intermediate layer can have a yarn density matching that of the machine-side layer. For example, for a fabric with four layers of MD yarns, the yarn density ratio, proceeding from the paper-side layer to the machine-side layer, can be 2:1:1:1, 3:1:1:1, 4:1:1:1, 2:2:1:1, 3:2:1:1, 4:2:1:1, 4:2:2:1, etc.

[0108] In some implementations in which there is more than one intermediate layer, a first intermediate layer that is closer to the paper side has a higher yarn density than a second intermediate layer that is closer to the machine side. This configuration can facilitate effective drainage and dewatering by the press fabric (based on the higher permeability / openness toward the machine side).

[0109] In addition to the MD layers, the press fabric 400 includes two systems of CD yarns. Yarns 404 of a first system of CD yarns bind together the paper-side layer 402-1 and the machine-side layer 402-3 with a four-end triple-layer sequence. The yarns 404 pass outside the paper-side layer 402-1 and pass outside the machine-side layer 402-3. In some implementations, the yarns 404 cross between aligned yarns of the intermediate layer 402-2 and the machine-side layer 402-3. In some implementations, in the sequence shown in FIGS. 4A-4C, the yarns 404 pass outside and bind a single yarn of the paper-side layer 402-1 (forming a knuckle 420-1) before extending back to inside the paper-side layer 402-1. In some implementations, the yarns 404 pass outside and bind a single yarn of the machine-side layer 402-3 (forming a knuckle 420-2) before extending back to inside the paper-side layer 402-3.

[0110] Yarns 406 of a second system of CD yarns form a single-layer sequence. The yarns 406 pass outside the paper-side layer 402-1 and remain inside the machine-side layer 402-3. For example, in the cross-machine direction, the yarns 406 pass outside the paper-side layer 402-1 (e.g., pass outside a single yarn of the paper-side layer 402-1), cross between aligned yarns of the layers 402-1 and 402-2, and extend adjacent to multiple consecutive yarns of the intermediate layer 402-2 (in the example of the press fabric 400, adjacent to four consecutive yarns of the intermediate layer 402-2, without being limited to that number in other implementations), before again passing outside the paper-side layer 402-1. When multiple intermediate layers are present, in some implementations, the yarns 406 extend adjacent to multiple consecutive yarns of an intermediate layer that is closest to the paper-side layer, among the multiple intermediate layers (an uppermost intermediate layer). When multiple intermediate layers are present, in some implementations, the yarns 406 cross between the paper-side layer and the uppermost intermediate layer.

[0111] In some implementations, the yarns 406 remain on the paper side of the intermediate layer 402-2, e.g., do not cross between the intermediate layer 402-2 and the machine-side layer 402-3 and / or do not pass to a machine side of the intermediate layer 402-2. When multiple intermediate layers are present, in some implementations, the yarns 406 remain on the paper side of the multiple intermediate layers. In some implementations, these configurations contribute to a higher permeability / openness toward the machine side of the press fabric 400, e.g., because the press fabric 400 includes voids, on the machine side of the intermediate layer(s), that would otherwise be filled by the yarns 406. However, other weave patterns of the yarns 406 are within the scope of this disclosure.

[0112] Based on the foregoing configuration, the yarns 406 separate the paper-side layer 402-1 from the intermediate layer 402-2 with binding upward toward the paper side. As such, the void volume of the press fabric 400, and / or the permeability / openness toward the machine side of the press fabric 400, is increased, promoting drainage and dewatering by the press fabric 400. When multiple intermediate layers are present, in some implementations, the yarns 406 separate the paper-side layer 402-1 from an uppermost intermediate layer.

[0113] Each of the first and second systems of CD yarns 404, 406 includes four ends. Along the machine direction, CD yarns 404 alternate with CD yarns 406, as shown in FIG. 4B. The yarns of the press fabric 400 can have composition(s) as described for the yarns of the press fabric 100. The CD yarns 404 can bind every eighth yarn of the paper-side layer 402-1 and every fourth yarn of the machine-side layer 402-3. The CD yarns 406 can bind every eight yarn of the paper-side layer 402-1, forming knuckles 422.

[0114] In some implementations, a press fabric includes three systems of CD yarns. For example, a first system can bind together the paper-side and machine-side layers; a second system can separate the paper-side layer from intermediate layer(s); and a third system can separate intermediate layer(s) from the machine-side layer.

[0115] For example, FIGS. 5A-5C illustrate an example of a press fabric 500 including three MD layers 402-1, 402-2, 402-3 and three systems of CD yarns. FIG. 5A is a side sectional view facing along the machine direction, FIG. 5B is a diagrammatic representation of the weave of the press fabric 500 facing along the CD axis from the left-most edge of FIG. 5A, and FIG. 5C is a perspective sectional view.

[0116] The three MD layers 402-1, 402-2, 402-3 can have characteristics as described for the corresponding layers of the press fabric 400. A first system of CD yarns 504, which binds together the paper-side layer 402-1 and the machine-side layer 402-3, has characteristics as described for the first system of CD yarns 404, e.g., forms a triple-layer sequence with four ends and passes outside each of the paper-side layer 402-1 and machine-side layer 402-3.

[0117] A second system of CD yarns 506, forming a single-layer sequence, is configured to separate the paper-side layer 402-1 and the intermediate layer 402-2 with binding toward the paper side. The second system of CD yarns 506 passes outside the paper-side layer 402-1 and remains inside the machine-side layer 402-3. In some implementations, the second system of CD yarns 506 remains on a paper side of the intermediate layer 402-2. The CD yarns 506 extend adjacent to multiple consecutive yarns of the intermediate layer 402-2, e.g., two consecutive yarns as shown in FIGS. 5A-5C. The CD yarns 506 can have characteristics as described for the CD yarns 406 of the press fabric 400, except as shown otherwise or described otherwise herein. As discussed in reference to FIGS. 4A-4C, the separation provided between the paper-side layer 402-1 and the intermediate layer 402-2 with upward binding can increase the void volume of the press fabric 500 and / or the permeability / openness toward the machine side of the press fabric 500.

[0118] A third system of CD yarns 508 is configured to separate the intermediate layer 402-2 and the machine-side layer 402-3 with binding toward the paper side (up into the intermediate layer 402-2). The CD yarns 508 can have composition(s) as described for the CD yarns of the press fabrics 100, 200, 300, and 400. The CD yarns 508 form a single-layer sequence that remains inside the machine-side layer 402-3, which can contribute to an increased void volume of the press fabric 500 and / or the permeability / openness toward the machine side of the press fabric 500. The CD yarns 508 can cross between aligned yarns of the intermediate layer 402-2 and the paper-side layer 402-1, e.g., at positions where the CD yarns 508 pass above single yarns of the intermediate layer 402-2. When multiple intermediate layers are included, in some implementations, the CD yarns 508 cross between aligned yarns of an intermediate layer closest to the machine-side layer 402-3 (a lowest intermediate layer) and an adjacent intermediate layer (a second-lowest intermediate layer), e.g., at positions where the CD yarns 508 pass above single yarns of the lowest intermediate layer.

[0119] The CD yarns 508 can extend adjacent to multiple consecutive yarns of the machine-side layer 402-3 and the intermediate layer 402-2 between the machine-side layer 402-3 and the intermediate layer 402-2, so as to separate the machine-side layer 402-2 from the intermediate layer 402-2. For example, as shown in FIGS. 5A and 5C, the CD yarns 508 can extend adjacent to three consecutive yarns of the machine-side layer 402-3.

[0120] Because the CD yarns 508 separate the intermediate layer 402-2 from the machine-side layer 402-3 by binding upward, toward the paper side (e.g., by forming knuckles on top sides of the yarns of the intermediate layer 402-2), in some implementations the CD yarns 508 contribute to increased void volume in the press fabric 500 and / or increased permeability / openness toward the machine side of the press fabric 500, improving drainage and dewatering by the press fabric 500.

[0121] The first system of CD yarns 504 includes four ends, and the second and third systems of CD yarns 506, 508 each include two ends. Along the machine direction, CD yarns 504, 506, 508 follow a BACABACA pattern, where “A” is the CD yarns 504, “B” is the CD yarns 506, and “C” is the CD yarns 508. This configuration is shown in FIG. 5B. The CD yarns 504 can bind every eighth yarn of the paper-side layer 402-1 and every fourth yarn of the machine-side layer 402-3, forming knuckles 520. The CD yarns 506 can bind every fourth yarn of the paper-side layer 402-1, forming knuckles 522. The CD yarns 508 can bind every fourth yarn of the intermediate layer 402-2, forming knuckles 524. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 504, 506, 508.

[0122] In some implementations, a system of CD yarns that separates the machine-side layer from one or more intermediate layers is configured differently from the third system of CD yarns of the press fabric 500. For example, the yarns of the system can form a double-layer sequence (or other non-single-layer sequence), and / or the yarns can pass outside the paper-side layer.

[0123] In comparison to the press fabric 400, although the press fabric 500 includes an additional system of CD yarns, the systems of CD yarns 506 and 508 are two-end systems, whereas the system of CD yarns 406 is a four-end system. As such, the void volume provided by the press fabric 500 can be equal to or greater than the void volume provided by the press fabric 400.

[0124] FIGS. 6A-6C illustrate another example of a press fabric 600 including three MD layers 402-1, 402-2, 402-3 and three systems of CD yarns. FIG. 6A is a side sectional view facing along the machine direction, FIG. 6B is a diagrammatic representation of the weave of the press fabric 600 facing along the CD axis from the left-most edge of FIG. 6A, and FIG. 6C is a perspective sectional view.

[0125] The three MD layers 402-1, 402-2, 402-3 can have characteristics as described for the corresponding layers of the press fabric 400. A first system of CD yarns 604, which binds together the paper-side layer 402-1 and the machine-side layer 402-3, has characteristics as described for the first system of CD yarns 404, e.g., forms a triple-layer sequence with four ends and passes outside each of the paper-side layer 402-1 and machine-side layer 402-3.

[0126] A second system of CD yarns 606, forming a single-layer sequence, is configured to separate the paper-side layer 402-1 and the intermediate layer 402-2 with binding toward the paper side. The second system of CD yarns 606 passes outside the paper-side layer 402-1 and remains inside the machine-side layer 402-3. In some implementations, the second system of CD yarns 606 remains on a paper side of the intermediate layer 402-2. The CD yarns 606 extend adjacent to multiple consecutive yarns of the intermediate layer 402-2, e.g., four consecutive yarns as shown in FIGS. 6A-6C. The CD yarns 606 can have characteristics as described for the CD yarns 406 and / or 506 of the press fabrics 400, 500, except as shown or described otherwise herein.

[0127] A third system of CD yarns 608 is configured to separate the intermediate layer 402-2 and the machine-side layer 402-3 with binding toward the paper side (up into the paper-side layer 402-1). The CD yarns 608 can have composition(s) as described for the CD yarns of the press fabrics 100, 200, 300, 400, and 500. The CD yarns 608 form a double-layer sequence that passes outside the paper-side layer 402-1 and remains inside the machine-side layer 402-3, which can contribute to an increased void volume of the press fabric 600 and / or increased permeability / openness toward the machine side of the press fabric 600 towards the machine side of the press fabric 600. For example, the press fabric 600 is relatively denser towards its paper side and relatively less dense towards its machine side.

[0128] The CD yarns 608 can cross between aligned yarns of the machine-side layer 402-3 and the intermediate layer 402-2 and between aligned yarns of the intermediate layer 402-2 and the paper-side layer 402-1. The CD yarns 608 can pass outside single yarns of the paper-side layer 402-1, e.g., so as to bind the single yarns to exert a separating binding force toward the paper side. The CD yarns 608 can extend adjacent to multiple consecutive yarns of the machine-side layer 402-3 and the intermediate layer 402-2 between the machine-side layer 402-3 and the intermediate layer 402-2, so as to separate the machine-side layer 402-2 from the intermediate layer 402-2. For example, as shown in FIGS. 6A and 6C, the CD yarns 608 can extend adjacent to two consecutive yarns of the machine-side layer 402-3. Based on this configuration, the intermediate layer 402-2 can be separated from the machine-side layer 402-3 to increase a void volume in the press fabric 600 and maintain high permeability / openness at toward the machine-side layer 402-3, e.g., at the machine-side layer 402-3.

[0129] The first system of CD yarns 604 includes four ends, and the second and third systems of CD yarns 606, 608 each include two ends. Along the machine direction, CD yarns 604, 606, 608 follow a BACABACA pattern, where “A” is the CD yarns 604, “B” is the CD yarns 606, and “C” is the CD yarns 508. This configuration is shown in FIG. 6B. The CD yarns 604 can bind every eighth yarn of the paper-side layer 402-1 and every fourth yarn of the machine-side layer 402-3, forming knuckles 620. The CD yarns 606 and 608 can bind every eighth yarn of the paper-side layer 402-1, forming knuckles 622, 624. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 604, 606, 608.

[0130] Compared to the press fabric 500, the press fabric 600 may exhibit increased stability against compaction between the paper-side layer 402-1 and the intermediate layer 402-2, due to the longer extension of the CD yarns 606 in comparison to the CD yarns 506. However, the press fabric 600 may have less-stable separation of the machine-side layer 402-3 from the intermediate layer 402-2 compared to the press fabric 500, due to the difference in configuration between the CD yarns 508 and 608.

[0131] It will be understood that other configurations of the third system of CD yarns are also within the scope of this disclosure. For example, in some implementations that include multiple intermediate layers, a system of CD yarns that separates the lowest intermediate layer from the machine-side layer is woven around yarns of another intermediate layer, e.g., the second-lowest intermediate layer or higher intermediate layer.

[0132] FIGS. 7A-7C illustrate another example of a press fabric 700 having three MD layers. FIG. 7A is a side sectional view facing along the machine direction, FIG. 7B is a diagrammatic representation of the weave of the press fabric 700 facing along the CD axis from the left-most edge of FIG. 7A, and FIG. 7C is a perspective sectional view.

[0133] The MD layers 402-1, 402-2, 402-3 and the systems of CD yarns 704, 706 have generally the same characteristics as described for the corresponding layers / yarns of the press fabric 400. However, while the second system of CD yarns 406 is a four-end system having CD yarns 406 that bind every eighth yarn of the paper-side layer 402-1, the second system of CD yarns 706 is a two-end system having CD yarns 706 that bind every fourth yarn of the paper-side layer 402-1, forming knuckles 722. The CD yarns 706 extend adjacent to two consecutive yarns of the intermediate layer 402-2 between the intermediate layer 402-2 and the paper-side layer 402-1, to separate the intermediate layer 402-2 and the paper-side layer 402-1 with a binding force toward the paper side. Accordingly, the press fabric 700 can maintain its openness, promoting drainage and dewatering. The press fabric 700 can also provide the other advantages discussed with respect to the press fabric 400.

[0134] As shown in FIG. 7B, along the machine direction, each CD yarn 706 is followed by two CD yarns 704 in a repeating pattern. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 704, 706.

[0135] The scope of this disclosure is not limited to press fabrics having two or three MD layers. In some implementations, a press fabric as described herein includes four or more MD layers. For example, FIGS. 8A-8E illustrate an example of a press fabric 800 having four MD layers. FIG. 8A is a side sectional view facing along the machine direction; FIGS. 8B-8C are top and bottom views, respectively; FIG. 8D is a perspective sectional view; and FIG. 8E is a side sectional view facing along the cross-machine direction. In FIGS. 8A-8E, reference letter “A” indicates a common position of the pattern of the press fabric.

[0136] Of four MD layers 802 in the press fabric 800, layer 802-1 is a paper-side layer, layer 802-4 is a machine-side layer, and layers 802-2, 802-3 are intermediate layers. These layers can have characteristics as described for the corresponding layers of the press fabrics 100, 200, 300, 400, 500, 600, and 700. For example, a yarn density of the paper-side 802-1 can be higher than a yarn density of the machine-side layer 802-4 and higher than yarn densities of at least one of, or all of, the intermediate layers 802-2, 802-3. In some implementations, as shown in FIGS. 8A-8E, the intermediate layers 802-2, 802-3 and the machine-side layer 802-4 have a same yarn density that is less than the yarn density of the paper-side layer 802-1 (in this example, a 2:1 yarn density ratio).

[0137] The press fabric 800 further includes four systems of CD yarns. A first system of CD yarns 804 (of which only one yarn is labeled for clarity of illustration) binds together the paper-side layer 802-1 and the machine-side layer 802-4, e.g., forms a four-layer sequence, with four ends, that binds yarns of both the paper-side layer 802-1 and the machine-side layer 802-4 and passes outside both the paper-side layer 802-1 and the machine-side layer 802-4, forming knuckles 820.

[0138] Three separation systems of CD yarns 806, 808, 810 are included in the press fabric 800. The three systems of CD yarns 806, 808, 810 each form a two end, double-layer sequence and remain inside the machine-side layer 802-4 to contribute to increased permeability / openness at the machine side of the press fabric 800. The CD yarns 806, 808, 810 can have composition(s) as described for the CD yarns of the press fabrics 100, 200, 300, 400, 500, 600, and 700.

[0139] A first system of CD yarns 806 separates the paper-side layer 802-1 and the adjacent upper intermediate layer 802-2, binding yarns of the paper-side layer 802-1 (forming knuckles 822) and remaining toward a paper side of the intermediate layer 802-2. A second system of CD yarns 808 separates the two intermediate layers 802-2, 802-3, binding yarns of the upper intermediate layer 802-2 (forming knuckles 824, shown in FIG. 8D) and remaining toward a paper side of the lower intermediate layer 802-3. A third system of CD yarns 810 separates the lower intermediate layer 802-3 and the machine-side layer 802-4, binding yarns of the lower intermediate layer 802-3 (forming knuckles 826) and remaining toward a paper side of the machine-side layer 802-4 (e.g., remaining inside the machine-side layer 802-4). Based on these weave patterns, each system of CD yarns 806, 808, 810 performs its separation function with an upward binding force, contributing to an increased permeability / openness toward the machine side of the press fabric 800 to promote drainage and dewatering.

[0140] Along the machine direction, CD yarns 804, 806, 808, 810 follow an ABACADABACAD pattern, where “A” is the CD yarns 804, “B” is the CD yarns 806, “C” is the CD yarns 808, and “D” is the CD yarns 810. The CD yarns 804 can bind every twelfth yarn of the paper-side layer 802-1 and every sixth yarn of the machine-side layer 802-4. The CD yarns 806 can bind every fourth yarn of the paper-side layer 802-1, passing adjacent to two consecutive yarns of the upper intermediate layer 802-2 between the paper-side layer 802-1 and the upper intermediate layer 802-2. The CD yarns 808 can bind every sixth yarn of the upper intermediate layer 802-2, passing adjacent to five consecutive yarns of the intermediate layers 802-2, 802-3 between the intermediate layers 802-2, 802-3. The CD yarns 810 can bind every sixth yarn of the lower intermediate layer 802-3, passing adjacent to five consecutive yarns of the lower intermediate layer 802-3 and the machine-side layer 802-4 between the lower intermediate layer 802-3 and the machine-side layer 802-4. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 806, 808, 810.

[0141] FIG. 9 illustrates another example of a press fabric 900. The press fabric 900 includes three MD layers 402-1, 402-2, 402-3. Further, the press fabric 900 includes two systems of binding yarns. A first system of CD yarns 904-1 (a three-end sequence) binds the machine-side layer 402-3 to the intermediate layer 402-2, passing outside the machine-side layer 402-3 and remaining toward the machine side of the paper-side layer 402-1. A second system of CD yarns 904-2 (a two-end sequence) binds the paper-side layer 402-1 to the intermediate layer 402-2, passing outside the paper-side layer 402-1 and remaining toward the paper side of the machine-side layer 402-3. The two systems of CD yarns 904-1, 904-2 jointly bind the press fabric 900 together. The yarns of the press fabric 900 can have characteristics as described for corresponding yarns of the preceding examples.

[0142] The press fabric 900 also includes a separation system of CD yarns 906, which form a two-end, single-layer sequence that passes outside the paper-side layer 402-1 and remains towards a paper side of the intermediate layer 402-2. The CD yarns 906 extend adjacent to multiple consecutive yarns of the intermediate layer 402-2, e.g., three consecutive yarns as shown in FIG. 9.

[0143] The weave pattern of the press fabric 900 provides improved dewatering. For example, the CD yarns 906 separate the MD layers 402-1, 402-2 with an upward binding force that contributes to higher permeability / openness towards the machine side of the press fabric 900. The arrangement of the CD yarns 906 on the paper side of the intermediate layer 402-2 (e.g., not extending in the machine-side layer 402-3) also contributes to higher permeability / openness in the machine-side layer 402-3. The higher yarn density of the paper-side layer 402-1 compared to the machine-side layer 402-3 also promotes water transfer to and out of the machine-side layer 402-3, to allow the press fabric 900 to better absorb and remove water.

[0144] FIG. 10 illustrates another example of a press fabric 1000. The press fabric 1000 includes four MD layers 1002-1, 1002-2, 1002-3, 1002-4. A paper-side layer 1002-1 has a yarn density ratio, with respect to upper and lower intermediate layers 1002-2, 1002-3 and a machine-side layer 1004-4, of 3:1. Further, the press fabric 1000 includes two systems of binding yarns. A first system of CD yarns 1004-1 performs a binding function, adding stability and reinforcing the structural integrity of the paper side of the press fabric 1000. A second system of CD yarns 1004-2 binds the paper-side layer 1002-1 to the upper intermediate layer 1002-2, passing outside the paper-side layer 1002-1 and remaining toward the paper side of the lower intermediate layer 1002-3. The arrangement of the CD yarns 1004-1, 1004-2 primarily at the paper side of the press fabric 1000 (e.g., remaining toward a paper side of the lower intermediate layer 1004-3) can contribute to increased permeability / openness toward the machine side of the press fabric 1000, promoting dewatering. The yarns of the press fabric 1000 can have characteristics as described for corresponding yarns of the preceding examples.

[0145] The press fabric 1000 also includes three separation systems of CD yarns 1006, 1008, 1010. The CD yarns 1006, which form a three-layer, two-end system, bind the machine-side layer 1002-4 (e.g., bind downward) and extend between the paper-side layer 1002-1 and the upper intermediate layer 1002-2 for three consecutive yarns of the upper intermediate layer 1002-2. The CD yarns 1008, which form a double-layer, two-end sequence, bind the machine-side layer 1002-4 (e.g., bind downward) and extend between the intermediate layers 1002-2, 1002-3 for three consecutive yarns of the intermediate layers 1002-2, 1002-3. The CD yarns 1010, which form a three-layer, two-end sequence, bind the paper-side layer 1002-1 (e.g., bind upward), extending between the lower intermediate layer 1002-3 and the machine-side layer 1002-4 for three consecutive yarns of the lower intermediate layer 1002-3. This weave arrangement can provide high permeability at the machine-side layer 1002-4, promoting water transfer through the machine-side layer 1002-4 and out of the press fabric 1000.

[0146] FIG. 11 illustrates another example of a press fabric 1100. The press fabric 1100 includes four MD layers 802-1, 802-2, 802-3, 802-4 as described with respect to FIGS. 8A-8E.

[0147] The press fabric 1100 includes two systems of binding yarns. A first system of CD yarns 1104-1 binds the paper-side layer 802-1 to the lower intermediate layer 802-3. A second system of CD yarns 1104-2 binds the paper-side layer 1002-1 to the upper intermediate layer 802-2. Along the cross-machine direction, the CD yarns 1104-2 alternate between binding on the upper intermediate layer 802-2 (passing to the machine side of the upper intermediate layer 802-2) and passing between aligned yarns of the paper-side layer 802-1 and the upper intermediate layer 802-2). The arrangement of the CD yarns 1104-1, 1104-2 primarily at the paper side of the press fabric 1100 (e.g., with the CD yarns 1104-1 remaining toward a paper side of the lower intermediate layer 802-3 and the CD yarns 1104-2 remaining toward a paper side of the machine-side layer 802-4) can contribute to increased permeability / openness toward the machine side of the press fabric 1100, promoting dewatering. The yarns of the press fabric 1000 can have characteristics as described for corresponding yarns of the preceding examples.

[0148] The press fabric 1100 also includes three separation systems of CD yarns 1106, 1108, 1110. The CD yarns 1106, which form a three-layer, two-end system, bind the machine-side layer 802-4 (e.g., bind downward) and extend between the paper-side layer 802-1 and the upper intermediate layer 802-2 for three consecutive yarns of the upper intermediate layer 802-2. The CD yarns 1108, which form a double-layer, two-end sequence, bind the machine-side layer 802-4 (e.g., bind downward) and extend between the intermediate layers 802-2, 802-3 for three consecutive yarns of the intermediate layers 802-2, 802-3. The CD yarns 1110, which form a three-layer, two-end sequence, bind the paper-side layer 802-1 (e.g., bind upward), extending between the lower intermediate layer 802-3 and the machine-side layer 802-4 for three consecutive yarns of the lower intermediate layer 802-3. This weave arrangement can provide high permeability at the machine-side layer 802-4, promoting water transfer through the machine-side layer 802-4 and out of the press fabric 1100.

[0149] FIG. 12 illustrates another example of a press fabric 1200. The press fabric 1200 includes four MD layers 1202-1, 1202-2, 1202-3, 1202-4. Yarn density ratios of a paper-side layer 1202-1, upper and lower intermediate layers 1202-2, 1202-3, and a machine-side layer 1204-4 are 2:2:1:1. Further, the press fabric 1200 includes two systems of binding yarns. A first system of CD yarns 1204-1 performs a binding function, adding stability and reinforcing the structural integrity of the paper side of the press fabric 1200. A second system of CD yarns 1204-2 binds the paper-side layer 1202-1 to the upper intermediate layer 1202-2, passing outside the paper-side layer 1202-1 and remaining toward the paper side of the lower intermediate layer 1202-3. The arrangement of the CD yarns 1204-1, 1204-2 primarily at the paper side of the press fabric 1200 (e.g., remaining toward a paper side of the lower intermediate layer 1204-3) can contribute to increased permeability / openness toward the machine side of the press fabric 1200, promoting dewatering. The yarns of the press fabric 1200 can have characteristics as described for corresponding yarns of the preceding examples.

[0150] The press fabric 1200 also includes three separation systems of CD yarns 1206, 1208, 1210. The CD yarns 1206, which form a three-layer, two-end system, bind the machine-side layer 1202-4 (e.g., bind downward) and extend between the paper-side layer 1202-1 and the upper intermediate layer 1202-2 for five consecutive yarns of the upper intermediate layer 1202-2. The CD yarns 1208, which form a double-layer, two-end sequence, bind the machine-side layer 1202-4 (e.g., bind downward) and extend between the intermediate layers 1202-2, 1202-3 for three consecutive yarns of the lower intermediate layer 1202-3. The CD yarns 1210, which form a three-layer, two-end sequence, bind the paper-side layer 1202-1 (e.g., bind upward), extending between the lower intermediate layer 1202-3 and the machine-side layer 1202-4 for three consecutive yarns of the lower intermediate layer 1202-3. This weave arrangement can provide high permeability at the machine-side layer 1202-4, promoting water transfer through the machine-side layer 1202-4 and out of the press fabric 1200.

[0151] FIG. 13 illustrates another example of a press fabric 1300. The press fabric 1300 includes four MD layers 1302-1, 1302-2, 1302-3, 1302-4. Yarn density ratios of a paper-side layer 1302-1, upper and lower intermediate layers 1302-2, 1302-3, and a machine-side layer 1302-4 are 3:3:1:1. Further, the press fabric 1300 includes two systems of binding yarns. A first system of CD yarns 1304-1 performs a binding function, adding stability and reinforcing the structural integrity of the paper side of the press fabric 1300. A second system of CD yarns 1304-2 binds the paper-side layer 1302-1 to the upper intermediate layer 1302-2, passing outside the paper-side layer 1302-1 and remaining toward the paper side of the lower intermediate layer 1202-3. The arrangement of the CD yarns 1304-1, 1304-2 primarily at the paper side of the press fabric 1300 (e.g., remaining toward a paper side of the lower intermediate layer 1304-3) can contribute to increased permeability / openness toward the machine side of the press fabric 1300, promoting dewatering. The yarns of the press fabric 1300 can have characteristics as described for corresponding yarns of the preceding examples.

[0152] The press fabric 1300 also includes three separation systems of CD yarns 1306, 1308, 1310. The CD yarns 1306, which form a three-layer, two-end system, bind the machine-side layer 1302-4 (e.g., bind downward) and extend between the paper-side layer 1302-1 and the upper intermediate layer 1302-2 for seven consecutive yarns of the upper intermediate layer 1302-2. The CD yarns 1308, which form a double-layer, two-end sequence, bind the machine-side layer 1302-4 (e.g., bind downward) and extend between the intermediate layers 1302-2, 1302-3 for three consecutive yarns of the lower intermediate layer 1302-3. The CD yarns 1310, which form a three-layer, two-end sequence, bind the paper-side layer 1302-1 (e.g., bind upward), extending between the lower intermediate layer 1302-3 and the machine-side layer 1302-4 for three consecutive yarns of the lower intermediate layer 1302-3. This weave arrangement can provide high permeability at the machine-side layer 1302-4, promoting water transfer through the machine-side layer 1302-4 and out of the press fabric 1300.

[0153] FIG. 14 illustrates another example of a press fabric 1400. The press fabric 1400 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1400 includes a system of binding yarns 1404 that binds the paper-side layer 402-1 to the machine-side layer 402-3, passing outside the paper-side layer 402-1 and the machine-side layer 402-3. The press fabric 1400 also includes a separation system of CD yarns 1406. The CD yarns 1406 form a single-layer, two-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the paper-side layer 402-1. The CD yarns 1406 separate the MD layers 402-1, 402-2 to improve permeability and openness towards the machine side of the press fabric 1400.

[0154] FIG. 15 illustrates another example of a press fabric 1500. The press fabric 1500 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1500 includes a system of binding yarns 1504 that binds the paper-side layer 402-1 to the machine-side layer 402-3, passing outside the paper-side layer 402-1 and the machine-side layer 402-3. The press fabric 1500 also includes a separation system of CD yarns 1506. The CD yarns 1506 form a double-layer, four-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the intermediate layer 402-2 and the machine-side layer 402-3 for three consecutive yarns of each of the intermediate layer 402-1 and the machine-side layer 402-3. By separating the intermediate layer 402-2 and the machine-side layer 402-3 with upward binding, the CD yarns can increase permeability and openness of the press fabric 1500 at the machine side.

[0155] FIG. 16 illustrates another example of a press fabric 1600. The press fabric 1600 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1600 includes a binder system of CD yarns 1604. The CD yarns 1604 bind the paper-side layer 402-1 and the machine-side layer 402-3, passing outside the paper-side layer 402-1 and the machine-side layer 402-3. The CD yarns 1604-2 bind the intermediate layer 402-2 and the machine-side layer 402-3, passing outside the machine-side layer 402-3, remaining inside the paper-side layer 402-1, and extending between the intermediate layer 402-2 and the paper-side layer 402-2. The press fabric 1600 also includes three separation systems of CD yarns 1606, 1608, 1610. The CD yarns 1606 form a single-layer, two-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the paper-side layer 402-1. The CD yarns 1608 form a double-layer, two-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the intermediate layer 402-2 and the machine-side layer 402-3 for four consecutive yarns of each of the intermediate layer 402-2 and the machine-side layer 402-3. The CD yarns 1610 form a double-layer, two-end system and bind the machine-side layer 402-3, extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the intermediate layer 402-2. By separating the paper-side layer 402-1 and the intermediate layer 402-2 (for the CD yarns 1606, 1610) or the intermediate layer 402-2 and the machine-side layer 402-3 (for the CD yarns 1608) with a force toward the paper-side layer 402-1, the CD yarns 1606, 1608 contribute to increased permeability / openness toward the machine side of the press fabric 1600, promoting dewatering.

[0156] FIG. 17 illustrates another example of a press fabric 1700. The press fabric 1700 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. A binder system of CD yarns 1704 binds the paper-side layer 402-1 and the machine-side layer 402-3. A separation system of CD yarns 1706 forms a double-layer, four-end system, extending between the intermediate layer 402-2 and the machine-side layer 402-3 for four consecutive yarns of each of the intermediate layer 402-2 and the machine-side layer 402-3. The CD yarns 1707 form a double-layer, four-end system and bind the paper-side layer 402-1 to bind upward. This weave arrangement can provide high permeability at the machine-side layer 402-3, promoting water transfer through the machine-side layer 402-3 and out of the press fabric 1700.

[0157] FIG. 18 illustrates another example of a press fabric 1800. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1800 includes a binder system of CD yarns 1804 that binds the paper-side layer 402-1 and the machine-side layer 402-3. The press fabric 1800 also includes a separation system of CD yarns 1806, which form a double-layer, four-end system that binds on the paper-side layer 402-1 to bind upward. The CD yarns 1806 perform a dual separation function, extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the paper-side layer 402-1 and two consecutive yarns of the intermediate layer 402-2, and also extending between the intermediate layer 402-2 and the machine-side layer 402-3 for four consecutive yarns of each of the intermediate layer 402-2 and the machine-side layer 402-3. The CD yarns 1806 separate the layers 402-1, 402-2, 402-3 with an upward binding force to improve the openness / permeability of the press fabric 1800 (e.g., at the machine side) and promote water transfer.

[0158] In some implementations, a press fabric includes straight yarns configured as separation yarns. For example, a CD yarn serving a separation function can extend straight between two specific MD layers of the press fabric, e.g., without crossing between MD layers.

[0159] For example, FIG. 27 illustrates an example of a two-layer press fabric 2700 having a straight separation yarn 2708. The press fabric 2700 can be understood as a variation of the press fabric 100. The separation yarn 2708 extends continuously between the paper-side layer 102-1 and the machine-side layer 102-2. It will be understood that the press fabric 2700 can have a system of separation yarns 2708 spaced apart from one another in the machine direction. The press fabric 2700 also includes a system of CD binder yarns 104 that bind the paper-side layer 102-1 and the machine-side layer 102-2, and a system of CD separation yarns 2706 that weave alternately over and under yarns of the paper-side layer 102-1, remaining on the paper side of the machine-side layer 102-2.

[0160] FIG. 28 illustrates an example of a three-layer press fabric 2800 having a straight separation yarn 2808. The press fabric 2800 can be understood as a variation of the press fabric 500. The separation yarn 2808 extends continuously between the intermediate layer 402-2 and the machine-side layer 402-3, performing a separation function that enhances the water extraction capabilities of the press fabric 2800. It will be understood that the press fabric 2800 can have a system of separation yarns 2808 spaced apart from one another in the machine direction. The press fabric 2800 also includes a system of CD binder yarns 504 that bind the paper-side layer 402-1 and the machine-side layer 402-3, and a system of CD separation yarns 506 that form a single-layer sequence as described with respect to the press fabric 500.

[0161] Although the separation yarn 2808 is shown as a straight yarn extending between the intermediate layer 402-2 and the machine-side layer 402-3, straight separation yarns within the scope of this disclosure are not limited to that configuration, and straight separation yarns may additionally or alternatively be included between a paper-side layer and an intermediate layer, and / or between intermediate layers.

[0162] As will be understood from the foregoing description, various combinations of numbers of binder systems and separation systems are within the scope of this disclosure. For example, the press fabrics 100, 200, 300, 400, 700, 1400, 1500, 1700, and 1800 each include one binder system and one separation system; the press fabrics 500 and 600 each include one binder system and two separation systems; the press fabrics 800, 1600 include one binder system and three separation systems; the press fabric 900 includes two binder systems and one separation system; and the press fabrics 1000, 1100, 1200, 1300 include two binder systems and three separation systems. Other combinations of these numbers are also within the scope of this disclosure.

[0163] In some implementations, a press fabric includes MD yarns in the paper-side layer (in this paragraph, referred to as “first yarns”) that are aligned with MD intermediate-layer yarns and MD yarns in the machine-side layer, and MD yarns in the paper-side layer (in this paragraph, referred to as “second yarns”) that are not aligned with, or are offset laterally from, the MD intermediate-layer yarns and MD machine-side yarns. This configuration is illustrated in all of the press fabrics of FIGS. 4A to 18. For example, the first yarns and the second yarns can alternate along the cross-machine direction, though the scope of this disclosure is not limited thereto, as shown, for example, in FIG. 10. In some implementations, it can be advantageous for separation yarns to bind on (e.g., form knuckles with) the second yarns, and for binder yarns to bind on (e.g., form knuckles with) the first yarns. For example, these separation yarns can form knuckles on top sides of (above) the second yarns, thereby separating with a force toward the paper side. This configuration is shown, for example, for press fabrics 400, 500, 600, 700, 800, 900, 1500, 1600, 1700, and 1800. In some implementations, having at least some of the separation yarns bind on the offset second yarns can be particularly advantageous, because, this configuration can provide a more symmetrical paper-side surface of the press fabric, improving smoothness of the paper side. This configuration may also facilitate easier or more efficient weaving of the press fabric, e.g., may provide weaving compatibility with a wider range of weaving machines. However, the scope of this disclosure is not limited to the foregoing configuration. For example, press fabrics 1000, 1100, 1200, 1300, and 1400 include separation yarns that bind on (form knuckles on) the first yarns, a configuration that can also advantageously provide an upward binding force that improves dewatering by the press fabric. Moreover, press fabrics 1000, 1100, 1200, and 1300 further include separation yarns that bind on yarns of the machine-side layer, thereby providing a downward binding force, to illustrate that the scope of this disclosure is not limited to separation yarns having an upward binding force.

[0164] In some implementations, a multi-layer press fabric includes specially-configured yarns in its seam area. For example, a multi-layer press fabric can include a combination of (i) one or more first additional yarns woven into the top layer of multiple layers and (ii) one or more second additional yarns woven into the seam loop. Together, these additional yarns can provide a synergistic effect that results in a reinforced seam area that exhibits improved lifetime. Further, the improved flap integrity provided by these additional yarns can result in less paper marking, due to better press and flow distribution. In some implementations, the yarns are texturized yarns. One or both types of additional yarns can be incorporated into any of the examples of press fabrics described herein.

[0165] FIG. 19 illustrates an example of a seam area of a three-layer press fabric 1900. For example, the press fabric 1900 can be any of the three-layer press fabrics described herein, such as press fabrics 400, 500, 600, 700, 900, 1400, 1500, 1600, 1700, 1800, or 2800. It will be understood, however, that the seam area configuration described with respect to FIG. 19 is also applicable to press fabrics with other numbers of layers, such as four-layer press fabrics, e.g., press fabrics 800, 1000, 1100, 1200, and 1300.

[0166] The press fabric 1900 includes two layers of MD yarns 1904 forming seam loops 1903 that can be joined together by a pintle or other joining element 1902, to form a seam 1901. A top layer of MD yarns 1910 is arranged above the seam 1901. The press fabric 1900 can be on-machine seamable. To provide the press fabric 1900 on the rolls (e.g., press rolls) of a papermaking machine, a flap can be cut through the top layer of MD yarns 1910 and an overlying staple fiber batt layer, to provide access to the seam 1901. However, absent the addition of yarns as described herein, the press fabric may lack CD yarns above the seam 1901, resulting in poor web anchorage on the top layer of MD yarns 1910, e.g., poor anchorage between the batt layer and the woven layers. Moreover, the removal of batt associated with the on-machine seaming process may change the air and water permeability of the seam area compared to the rest of the press fabric 1900. This difference in water permeability, or flow resistance, may cause sheet marking.

[0167] To improve performance of the press fabric 1900, first additional CD yarns 1906 are woven in the top layer (e.g., paper-side layer) of MD yarns 1910, in the seam area over the seam loops 1903. For example, the first additional CD yarns 1906 can be woven in only the top layer. For example, the first additional CD yarns 1906 can be woven with a plain-weave configuration, alternately weaving over and under the top layer of MD yarns 1910. The first additional CD yarns 1906 provides extra yarns for web anchorage, improving the mechanical properties of the press fabric 1900. In some implementations, a first first additional CD yarn 1906 is arranged on one side of the joining element 1902 in the machine direction, and a second first additional CD yarn 1906 is arranged on the other side of the joining element 1902 in the machine direction. The first additional CD yarns 1906 can be woven into a flap area that extends over the seam 1901. For example, the flap area can be an area that becomes a flap when cuts are made to permit on-machine seaming.

[0168] The press fabric 1900 further includes second additional CD yarns 1908 that are woven into the loops 1903 of the seam 1901. The second additional CD yarns 1908 can strengthen web anchorage down to the loops 1903. For example, the second additional CD yarns 1908 can be woven into the top layer of the loops 1903, adjacent to the top layer of MD yarns 1910. For example, the second additional CD yarns 1908 can be woven with a plain-weave configuration, alternately weaving over and under the top layer of the loops 1903. In some implementations, a first second additional CD yarn 1908 is arranged on one side of the joining element 1902 in the machine direction, and a second second additional CD yarn 1908 is arranged on the other side of the joining element 1902 in the machine direction. The second additional CD yarns 1908 can be woven under a flap that extends over the seam 1901.

[0169] In some implementations, the first additional CD yarns 1906 and / or the second additional CD yarns 1908 are textured yarns. For example, the first additional CD yarns 1906 and / or the second additional CD yarns 1908 can be multifilament yarns formed by tens of (e.g., at least 50) micro-yarns.

[0170] The first additional CD yarns 1906 and / or the second additional CD yarns 1908 can be the closest CD yarns to the seam 1901, among CD yarns of the press fabric 1900. For example, other CD yarns may be spaced laterally apart from the seam 1901, whereas the first additional CD yarns 1906 and / or the second additional CD yarns 1908 can vertically overlap the seam 1901 and / or the joining element 1902 or can be very close laterally to the seam 1901 and / or the joining element 1902. The other CD yarns can be, for example, separation yarns and / or binder yarns. For example, the other CD yarns can be yarns of a different type than the texturized yarns, such as non-texturized yarns.

[0171] The first additional CD yarns 1906 and / or the second additional CD yarns 1908, and especially the CD yarns 1906 and 1908 in combination with one another, can provide reinforced seams that exhibit high performance throughout the press fabric lifetime. For example, the first additional CD yarns 1906 and / or the second additional CD yarns 1908 can improve web flap integrity to reduce marking, as a result of better press and flow distribution. Fiber anchorage can be improved on the flap and non-flap sides. Web loss in the cut top layers over the seam 1901 can be reduced, avoiding seam-marks and paper cuts.

[0172] FIG. 20 illustrates another example of a press fabric 2000 including additional CD yarns in the seam area. The press fabric 2000 is similar to the press fabric 1900 of FIG. 19, and the elements of FIG. 20 can have characteristics as described for the corresponding elements of FIG. 19, except where noted otherwise or suggested otherwise by context.

[0173] The press fabric 2000 includes two layers of MD yarns 2004 forming seam loops 2003 that can be joined together by a joining element 2002, to form a seam 2001. A top layer of MD yarns 2010 is arranged above the seam 2001. First additional CD yarns 2006 (in this example, four first additional CD yarns 2006) are woven in the top layer of MD yarns 2010. Second additional CD yarns 2008 that are woven into the loops 2003 of the seam 2001.

[0174] Compared to FIG. 19, FIG. 20 further illustrates other CD yarns 2012, which are omitted from FIG. 19 for clarity of illustration and description. In some implementations, the CD yarns 2012 can include one or more systems of binder yarn and one or more systems of separation yarns, having weave configurations as described with respect to FIGS. 1 to 18. Thus, the advantageous weave configurations described with respect to FIGS. 1 to 18 can be realized in conjunction with improved seam areas as described with respect to FIGS. 19 and 20.

[0175] To provide one example, the intermediate layer 402-2 and the machine-side layer 402-3 of the three-layer press fabric 400 (illustrated in FIGS. 4A-4C) can form seam loops having second additional CD yarns woven therein, and / or the paper-side layer 402-1 can be the “top layer” (discussed with respect to FIGS. 19 and 20) having first additional CD yarns woven therein. As another example, at least two of the layers 802-2, 802-3, 802-4 of the four-layer press fabric 800 (described with respect to FIGS. 8A-8F) can form seam loops having second additional CD yarns woven therein, and / or the paper-side layer 802-1 can be the “top layer” having first additional CD yarns woven therein. In some implementations, the first additional CD yarns can be woven into multiple top layers. For example, the two lower layers 802-3, 802-4 can form seam loops, and the first additional CD yarns can be woven into the paper-side layer 802-1 or both the paper-side layer 802-1 and the upper intermediate layer 802-2. It will be understood that this description can equally be extended to the other three-layer and four-layer press fabrics described herein. Further, the second additional CD yarns, which are woven into seam loops, can be included in two-layer press fabrics, such as press fabrics 100, 200, and 300.

[0176] FIGS. 21 and 22 are cross-sectional and top views, respectively, of a seam area having first additional yarns 2106. The first additional yarns 2106 extend over seam loops 2103 and are woven into the top layer of MD yarns 2110. As shown in FIGS. 21 and 22, the additional yarns can have a different composition, type, and / or diameter from other yarns of the press fabric. For example, FIGS. 21 and 22 illustrate the textured, multifilament composition of some implementations of the first additional yarns 2106, which have a larger diameter than other yarns of the press fabric.

[0177] In the foregoing description, for conciseness, binding and force characteristics illustrated in the drawings, and disclosed for some press fabrics in the description, are sometimes omitted from the description for other press fabrics. However, it will be understood that, when a yarn configuration, and / or a benefit thereof, is described in reference to an illustrated example, the same yarn configuration, and / or the benefit thereof, applies equally to matching illustrated examples. In any of the press fabrics described herein, a CD separation yarn that forms a knuckle on a top side (paper side) of an MD yarn, exerts an upward binding force. When a CD yarn is described as extending adjacent to “consecutive” yarns of an MD layer, it will be understood that the CD yarn extends adjacent to the consecutive yarns of the MD layer while extending continuously adjacent to the MD layer and between the MD layer and an adjacent MD layer, e.g., without crossing between any MD layers.

[0178] The press fabrics described herein can be manufactured using any suitable weaving method. For example, in some implementations, the press fabrics are manufactured in an endless weaving machine. In some implementations, the press fabrics are woven by the endless weaving machine with the paper-side layer on the inside and the machine-side layer on the outside. The woven fabric can then be turned inside-out (such that the paper-side layer faces out) and mounted on rolls for use in pressing. In some implementations, the press fabrics are manufactured using a flat weaving machine. In that case, in some implementations, the woven fabric is joined / sewn to itself after weaving to form a loop suitable for mounting on rolls for use in pressing.

[0179] In some implementations, the press fabrics described herein can be manufactured using a relatively small number of harnesses, e.g., for improved manufacturing flexibility compared to press fabrics that require a higher number of harnesses. For example, in some implementations, press fabrics 100, 200, and 700 can be manufactured using twelve-harness weaving machines, and press fabrics 300, 400, 500, and 600 can be manufactured using sixteen-harness weaving machines. In some implementations, press fabric 800 can be manufactured using a 24-harness weaving machine. This relative ease of manufacturing can be associated with the CD yarn counts included in the press fabrics described herein. For example, the CD yarn systems of the press fabrics 100, 200, and 700 include six CD yarns, and the CD yarn systems of the press fabrics 300, 400, 500, and 600 include eight CD yarns. These relatively low CD yarn counts can be based on the weave patterns of the separation yarns described herein and contrast with some alternative weaves that incorporate higher CD yarn counts, e.g., twelve CD yarns in a three-layer weave.

[0180] The press fabrics described herein can include one or more batt layers. For example, a batt layer can be provided on the paper side and / or the machine side of any of the press fabrics described herein. The batt can be needled through layers of the press fabric to join the layers to one another. For example, needling can join the batt, a top layer of the press fabric, and lower layers of the press fabric that form a seam loop. For example, one or more batt layers can be attached to any layers of the press fabrics described herein, e.g., attached to the paper-side layer and / or the machine-side layer.

[0181] Accordingly, press fabrics for paper manufacture can be configured for improved water removal. Based on yarn densities of MD layers and / or weave patterns of CD yarn systems, void volume, permeability, and openness can be increased, and drainage and dewatering can be improved. Further, in some implementations, these advantages can be achieved without compromising the strength of the fabric and its ability to support paper.

[0182] While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular implementations of particular inventions. Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Examples

Embodiment Construction

[0077]Various aspects of this disclosure describe fabrics and weave patterns for use in papermaking, e.g., as press fabrics. In some implementations, the disclosed fabrics can exhibit high void volume, openness, and binding characteristics that improve water removal from paper sheets and water transfer out of the fabrics themselves.

[0078]During the press section of a papermaking process, the efficacy of water removal from the paper sheet depends in large part on the characteristics of the press fabric. For example, fabrics with higher void volume (the open volume within the fabric that is not occupied by yarns / fibers) may be able to remove more water, as the voids provide space for water storage, thereby improving dewatering / water removal for the paper sheet. Layers of the press fabric with higher permeability / openness can also promote water removal. For example, when layers further from the paper sheet (e.g., a layer opposite the paper sheet) have higher permeability / openness, wate...

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 747,654, filed on Jan. 21, 2025, the entirety of which is incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to fabrics for paper manufacture.BACKGROUND

[0003] During papermaking processes, after a forming section in which a pulp slurry is formed into a sheet, the sheet is processed in a press section. The sheet is supported by press fabrics (or “felts”) that pass through a series of press nips, typically with increasing load at each nip. The loading of the nips generate a build-up of hydraulic pressure within the sheet, which leads to an expression of water from the sheet into the felt. This mechanical compaction process is known as wet pressing. The press fabric has a “paper side” on which the sheet is supported and a “machine side,” opposite the paper side, in contact with or otherwise adjacent to the machine elements such as rolls.SUMMARY

[0004] Some aspects of this disclosure relate to press fabrics for paper manufacture. For example, described a press fabric for paper manufacture, the press fabric including: three or more layers of machine direction (MD) yarns, wherein the three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. The paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer. The press fabric includes a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers; and a second system of CD yarns, wherein the CD yarns of the second system pass outside the paper-side layer and remain inside the machine-side layer.

[0005] This and other press fabrics described herein can have one or more of at least the following

[0006] In some implementations, the paper-side layer includes: first yarns that are aligned with corresponding yarns of the machine-side layer and the one or more intermediate layers; and second yarns that are offset from yarns of the machine-side layer and the one or more intermediate layers.

[0007] In some implementations, the CD yarns of the second system form knuckles on the paper side of the second yarns.

[0008] In some implementations, the CD yarns of the first system form knuckles on the paper side of the first yarns.

[0009] In some implementations, the first yarns alternate with the second yarns along the cross-machine direction.

[0010] In some implementations, the CD yarns of the second system form knuckles on the paper side of the first yarns.

[0011] In some implementations, the one or more intermediate layers and the machine-side layer include a same number of yarns per unit length along the cross-machine direction.

[0012] In some implementations, the paper-side layer has a 2:1 ratio of yarns per unit length along the cross machine direction with the one or more intermediate layers and with the machine-side layer.

[0013] In some implementations, the paper-side layer has a 2:1 ratio of yarns per unit length along the cross-machine direction with the machine-side layer.

[0014] In some implementations, the CD yarns of the second system separate the paper-side layer from the one or more intermediate layers.

[0015] In some implementations, the CD yarns of the second system include separation yarns with a binding force toward the paper side.

[0016] In some implementations, the CD yarns of the second system form a single-layer sequence.

[0017] In some implementations, the CD yarns of the second system, while extending continuously adjacent to a layer that is closest to the paper-side layer among the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the layer that is closest to the paper-side layer.

[0018] In some implementations, the CD yarns of the second system, while extending continuously between the paper-side layer and a layer that is closest to the paper-side layer among the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the paper-side layer.

[0019] In some implementations, the CD yarns of the second system remain toward the paper side of the one or more intermediate layers.

[0020] In some implementations, the CD yarns of the second system form knuckles on the paper side of yarns of the paper-side layer.

[0021] In some implementations, the press fabric includes a third system of CD yarns. The CD yarns of the third system extend between the machine-side layer and the one or more intermediate layers and remain inside the machine-side layer.

[0022] In some implementations, the CD yarns of the third system bind, toward the paper side, a layer that is closest to the machine-side layer among the one or more intermediate layers.

[0023] In some implementations, the CD yarns of the third system, while extending continuously between the machine-side layer and a layer that is closest to the machine-side layer among the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the machine-side layer.

[0024] In some implementations, the CD yarns of the third system extend between the paper-side layer and the one or more intermediate layers.

[0025] In some implementations, the CD yarns of the third system pass outside the paper-side layer.

[0026] In some implementations, the CD yarns of the third system remain inside the paper-side layer.

[0027] In some implementations, the CD yarns of the third system form a single-layer sequence.

[0028] In some implementations, the CD yarns of the third system form a double-layer sequence.

[0029] In some implementations, a permeability of the machine-side layer is higher than a permeability of the paper-side layer.

[0030] In some implementations, the one or more intermediate layers include a plurality of intermediate layers, and the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system extend between two intermediate layers of the plurality of intermediate layers, and wherein the CD yarns of the third system remain inside the paper-side layer and the machine-side layer.

[0031] In some implementations, the CD yarns of the third system form a double-layer sequence that separates the two intermediate layers from one another with a binding force toward the paper side.

[0032] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, the CD yarns of the second system include separation yarns with a binding force toward the paper side, and the press fabric of includes a third system of CD yarns, wherein the CD yarns of the third system include separation yarns with a binding force toward the machine side.

[0033] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers. The CD yarns of the second system form knuckles on the paper side of yarns of the paper-side layer, and the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system form knuckles on the machine side of yarns of the machine-side layer.

[0034] In some implementations, the CD yarns of the first system bind the paper-side layer together with the first intermediate layer of the one or more intermediate layers, and the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system bind the machine-side layer together with the first intermediate layer or a second intermediate layer of the one or more intermediate layers.

[0035] In some implementations, the CD yarns of the second system, while extending continuously adjacent to a layer of the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the layer.

[0036] In some implementations, the press fabric includes a third system of CD yarns. The CD yarns of the third system pass outside the machine-side layer and remain inside the paper-side layer.

[0037] In some implementations, the CD yarns of the third system extend between the paper-side layer and the one or more intermediate layers.

[0038] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, and wherein the CD yarns of the third system extend between two intermediate layers of the plurality of intermediate layers.

[0039] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, and the CD yarns of the first system remain toward a paper side of a layer that is closest to the machine-side layer among the plurality of intermediate layers.

[0040] In some implementations, the one or more intermediate layers includes a plurality of intermediate layers, the first intermediate layer has a same number of yarns per unit length along the cross-machine direction as the paper-side layer, a second intermediate layer of the plurality of intermediate layers has a same number of yarns per unit length along the cross-machine direction as the machine-side layer, and the second intermediate layer is closer to the machine-side layer than is the first intermediate layer.

[0041] In some implementations, MD yarns of two layers of the machine-side layer and the one or more intermediate layers form seam loops, and the press fabric includes: first CD yarns woven in the paper-side layer and arranged over the seam loops, and second CD yarns woven in the seam loops.

[0042] In some implementations, the first CD yarns and the second CD yarns include texturized yarns.

[0043] In some implementations, the first CD yarns are woven in a flap area that extends over the seam loops.

[0044] In some implementations, the first CD yarns and the second CD yarns are closer to the seam loops than are the first system of CD yarns and the second system of CD yarns.

[0045] In some implementations, the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system are straight yarns that extend between the paper-side layer and the one or more intermediate layers, between two intermediate layers of the one or more intermediate layers, or between the one or more intermediate layers and the paper-side layer.

[0046] In some implementations, the press fabric includes one or more layers of batt attached to at least one of the paper-side layer or the machine-side layer.

[0047] Some aspects of this disclosure describe another press fabric for paper manufacture. The press fabric includes: three or more layers of machine direction (MD) yarns, wherein the three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. The paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer. The press fabric includes a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers; and a second system of CD yarns, wherein the CD yarns of the second system separate the paper-side layer from the one or more intermediate layers.

[0048] This and other press fabrics described herein can have one or more of at least the following characteristics.

[0049] In some implementations, the press fabric includes a third system of CD yarns, wherein the CD yarns of the third system separate the machine-side layer from the one or more intermediate layers.

[0050] In some implementations, the CD yarns of the second system bind toward the paper side.

[0051] Some aspects of this disclosure described another press fabric for paper manufacture. The press fabric includes: a paper-side layer of machine direction (MD) yarns at a paper side of the press fabric; a machine-side layer of MD yarns at a machine side of the press fabric, wherein the paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer; a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer and the machine-side layer together; and a second system of CD yarns, wherein the CD yarns of the second system separate the paper-side layer from the machine-side layer.

[0052] This and other press fabrics described herein can have one or more of at least the following characteristics.

[0053] In some implementations, the CD yarns of the second system remain inside the machine-side layer.

[0054] In some implementations, the press fabric is a two-layer press fabric.

[0055] Some aspects of this disclosure described another press fabric for paper manufacture. The press fabric includes: three or more layers of machine direction (MD) yarns, wherein the three or more layers include: a paper-side layer at a paper side of the press fabric, a machine-side layer at a machine side of the press fabric, and one or more intermediate layers between the paper-side layer and the machine-side layer. MD yarns of two layers of the machine-side layer and the one or more intermediate layers form seam loops. The press fabric includes cross-machine direction (CD) yarns, wherein the CD yarns include first CD yarns woven in the paper-side layer and arranged over the seam loops, and second CD yarns woven in the seam loops.

[0056] This and other press fabrics described herein can have one or more of at least the following characteristics.

[0057] In some implementations, the first CD yarns and the second CD yarns include texturized yarns.

[0058] In some implementations, the press fabric includes a first system of CD yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers. The CD yarns of the first system have a different composition from the first CD yarns and the second CD yarns.

[0059] In some implementations, the first CD yarns and the second CD yarns are closer to the seam loops than are the first system of CD yarns.

[0060] The details of one or more implementations of the subject matter of this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0061] FIGS. 1A-1C are side sectional and perspective sectional views of an example of a two-layer press fabric.

[0062] FIGS. 2A-2C are side sectional and perspective sectional views of another example of a two-layer press fabric.

[0063] FIGS. 3A-3C are side sectional and perspective sectional views of another example of a two-layer press fabric.

[0064] FIGS. 4A-4C are side sectional and perspective sectional views of an example of a three-layer press fabric.

[0065] FIGS. 5A-5C are side sectional and perspective sectional views of another example of a three-layer press fabric.

[0066] FIGS. 6A-6C are side sectional and perspective sectional views of another example of a three-layer press fabric.

[0067] FIGS. 7A-7C are side sectional and perspective sectional views of another example of a three-layer press fabric.

[0068] FIGS. 8A-8F are side sectional, top, bottom, perspective, and two side sectional views of an example of a four-layer press fabric.

[0069] FIG. 9 is a side-sectional view of an example of a three-layer press fabric.

[0070] FIGS. 10-13 are side-sectional views of examples of four-layer press fabrics.

[0071] FIGS. 14-18 are side-sectional views of examples of three-layer press fabrics.

[0072] FIGS. 19, 23, and 24 are perspective, side, and top views, respectively, of an example of a press fabric including additional CD yarns.

[0073] FIGS. 20, 25, and 26 are perspective, top, and bottom views, respectively, of an example of a press fabric including additional CD yarns.

[0074] FIGS. 21 and 22 are side-view and top-view photographs, respectively, of an example of a press fabric including additional CD yarns.

[0075] FIG. 27 is a side-sectional view of an example of a two-layer press fabric.

[0076] FIG. 28 is a side-sectional view of an example of a three-layer press fabric.DETAILED DESCRIPTION

[0077] Various aspects of this disclosure describe fabrics and weave patterns for use in papermaking, e.g., as press fabrics. In some implementations, the disclosed fabrics can exhibit high void volume, openness, and binding characteristics that improve water removal from paper sheets and water transfer out of the fabrics themselves.

[0078] During the press section of a papermaking process, the efficacy of water removal from the paper sheet depends in large part on the characteristics of the press fabric. For example, fabrics with higher void volume (the open volume within the fabric that is not occupied by yarns / fibers) may be able to remove more water, as the voids provide space for water storage, thereby improving dewatering / water removal for the paper sheet. Layers of the press fabric with higher permeability / openness can also promote water removal. For example, when layers further from the paper sheet (e.g., a layer opposite the paper sheet) have higher permeability / openness, water can be transferred out of the press fabric through those layers, allowing more water to be absorbed from the paper side of the press fabric. At the same time, fabrics should have sufficient strength and resilience to remain stable under the high pressure exerted by the rolls. Weave characteristics of the fabric can also determine the drainability of the fabric, e.g., how easily water transferred from the paper sheet to the fabric can be removed from the fabric to facilitate further subsequent absorption by the fabric and improve dewatering of the paper sheet.

[0079] Some implementations according to this disclosure provide multi-layer press fabrics with high void volume and / or permeability at the machine side, e.g., higher openness at the machine side than at the paper side. This configuration can facilitate rapid water removal from sheets without compromising the fabrics'ability to support paper sheets. In some implementations, the press fabrics have higher yarn densities at the paper side than at the machine side (e.g., based on yarn counts in machine-direction layers, weave patterns of cross-machine direction separation layers / yarns, and / or binding directions of cross-machine direction separation layers / yarns), to improve water transfer out of the paper sheet and out of the press fabric. In some implementations, improved dewatering can be provided through configurations of “separation yarns” provided as cross-machine direction yarns in the press fabrics.

[0080] FIGS. 1A-1C illustrate an example of a two-layer press fabric 100 according to some implementations of the present disclosure. FIG. 1A is a side sectional view facing along a machine direction (MD), FIG. 1B is a side sectional view facing along a cross-machine direction (CD) axis from the left-most edge of FIG. 1A, and FIG. 1C is a perspective sectional view.

[0081] The press fabric 100 includes a paper-side layer (or top layer) 102-1 on which a paper sheet is placed for pressing, and a machine-side layer (or bottom layer) 102-2 opposite the paper-side layer. All side sectional views of press fabrics herein have this orientation. The paper-side layer 102-1 and the machine-side layer 102-2 are stacked on one another and include a series of threads or yarns extending parallel to one another in a machine direction (MD). Because these yarns extend in the machine direction, the yarns can be referred to as “MD yarns,” and the layers 102-1, 102-2 can be referred to as “MD layers”102. Consistent with standard terminology in the field, “machine direction” and “cross-machine direction” as used herein are with respect to the papermaking rolls with which the fabrics are used, e.g., which may not correspond to a machine direction and cross-machine direction with which the fabrics are weaved.

[0082] It will be understood that a “layer” as described herein, while being defined with respect to a certain set of MD yarns, can include CD yarns, for example, performing a binding and / or separation function on the MD yarns, and / or otherwise extending through or amongst the MD yarns of the layer. The presence of the CD yarns in MD layers is relevant, because the CD yarns partially determine the permeability / openness of the MD layer. For example, an MD layer in which a higher density of CD yarns is present may have a lower permeability than an MD layer in which a lower density of CD yarns is present. That is, the permeability / openness of an MD layer may depend on the CD yarns that are present in the layer, e.g., where more CD yarns may correspond to lower permeability. Some implementations of the weaves discussed herein provide higher permeability / openness in layers of MD yarns (e.g., layers at or near the machine side of the press fabric), at least in part based on the disclosed weave patterns of the CD yarns. As such, references herein to a “layer” of MD yarns do not preclude the presence of other yarns amongst the MD yarns of the layer.

[0083] The paper-side layer 102-1 need not be in direct contact with paper sheets. For example, in some implementations a layer of batt is present between the paper-side layer 102-1 and paper sheets, e.g., needled onto the paper side of the press fabric 100. The press fabrics described herein can constitute a base structure and should not be understood to preclude the presence of other layer(s) / material(s) such as batt. In some implementations, batt is present between the machine-side layer 102-2 and the roll. In some implementations, batt is present between layers of the press fabric 101. Other layers can instead or additionally be present. For example, a coating may be present on the layer of batt and / or between the layer of batt and the paper-side layer 102-1. For example, the press fabric may have a laminate structure including two or more separate weaves attached to one another, optionally with a coating or material (e.g., batt) in-between. One or more of the two or more separate weaves can have a weave structure as described for the press fabrics discussed herein.

[0084] The MD yarns making up the MD layers 102 can include, for example, monofilament, plied monofilament, multifilament, and / or plied multifilament yarn. In some implementations, the MD yarns are polymeric, e.g., polyamide yarns or polyester yarns, or any other suitable yarn. The respective yarns of the layers 102-1, 102-2 can be the same as one another and / or different from one another (e.g., in composition and / or type), and the yarns within each layer 102-1, 102-2 can be the same as one another and / or different from one another.

[0085] The paper-side layer 102-1 has a higher number of yarns per unit length along the cross-machine direction (CD, transverse to the extension direction of the MD layers 102) than the machine-side layer 102-2. For example, as shown in FIGS. 1A-1C, there can be twice as many yarns per unit length in the paper-side layer 102-1 as in the machine-side layer 102-2, for a 2:1 yarn density ratio (or yarn number ratio). In some implementations, as in the press fabric 100, some yarns of the paper-side layer 102-1 are aligned with corresponding yarns of the machine-side layer 102-2, and other yarns of the paper-side layer 102-1 may not be in alignment with a yarn of the machine-side layer 102-2. For example, alternating yarns of the paper-side layer 102-1 can be aligned with (e.g., directly above) corresponding yarns of the machine-side layer 102-2, and the remaining yarns of the paper-side layer 102-1 can be out-of-alignment with the yarns of the machine-side layer 102-2. Other yarn ratios and arrangements are also within the scope of this disclosure. For example, in some implementations, the paper-side layer 102-1 has a 3:1, 4:1, 3:2, or 5:2 yarn density ratio with the machine-side layer 102-2, or any other yarn density ratio greater than 1. These and other ratios are applicable not only to the press fabric 100 but also to other two-layer press fabrics within the scope of this disclosure.

[0086] Based on the difference in yarn counts (or yarn densities), in some implementations, a permeability / openness of the machine-side layer 102-2 is greater than a permeability / openness of the paper-side layer 102-1. For example, where alternating MD yarns are present in the paper-side layer 102-1, the machine-side layer 102-2 has no corresponding yarn; instead, a void is present. The presence of these voids in the machine-side layer 102-2 (or greater permeability or openness of the machine-side layer 102-2) can contribute to overall greater dewatering by the press fabric 100, e.g., because water from the paper side can more easily be transferred towards the machine side to be extracted from the press fabric 100, permitting more water to then be taken in at the paper side. In some implementations, the paper-side layer 102-1, although having a lower permeability than the machine-side layer 102-2, has a high strength corresponding to its increased yarn density. As such, the paper-side layer 102-1 is able to support paper sheets effectively on the paper-side layer 102-1.

[0087] The press fabric 100 also includes CD yarns that bind together the MD yarns and render the yarns a cohesive fabric. In some implementations, two systems of CD yarns are included. A first system of CD yarns includes CD yarns 104. The CD yarns 104 are configured to bind the layers 102-1, 102-2 together. For example, the CD yarns 104 can pass outside the paper-side layer 102-1 (to the paper side of the paper-side layer 102-1) and outside the machine-side layer 102-2 (to the machine side of the machine-side layer 102-2). As such, the CD yarns 104 can exert tension between the paper-side layer 102-1 and the machine-side layer 102-2. In some implementations, the CD yarns 104 cross between yarns (e.g., vertically-aligned yarns) of the paper-side layer 102-1 and the machine-side layer 102-2, respectively. The CD yarns 104 can be woven in a double-layer sequence, meaning that the CD yarns 104 pass outside two adjacent MD layers 102 (the layers 102-1 and 102-2). The CD yarns 104 bind sixth yarn of the paper-side layer 102-1 and every third yarn of the machine-side layer 102-2, forming knuckles 120. Yarns, such as the CD yarns 104, that bind together a paper-side layer and a machine-side layer, can be referred to as “binder yarns” or as constituting / forming a “binder system.”

[0088] A second system of CD yarns includes CD yarns 106. The CD yarns 106 are woven in a single-layer sequence passing outside the paper-side layer 102-1, crossing between the paper-side layer 102-1 and the machine-side layer 102-2, and remaining inside the machine-side layer 102-2 (remaining on a paper side of the machine-side layer 102-2). Because of this weave pattern (e.g., because the CD yarns 106 remain inside the machine-side layer 102-2), the CD yarns 106 permit a high permeability / openness in the machine-side layer 102-2, corresponding to increased dewatering by the press fabric 100.

[0089] The CD yarns 106 are configured to separate the MD layers 102-1, 102-2. For example, the CD yarns 106 can extend adjacent to multiple consecutive yarns of the machine-side layer 102-2, e.g., extend between the MD layers 102-1, 102-2 so as to pass adjacent to multiple consecutive yarns of the machine-side layer 102-2 without passing outside either MD layer 102-1, 102-2 during that extension. This configuration can be referred to as “flotation.” The CD yarns 106 pass outside single yarns of the paper-side layer 102-1, e.g., do not extend outside the paper-side layer 102-1 for multiple consecutive yarns of the paper-side layer 102-1, so as to bind single yarns of the paper-side layer 102-1, forming knuckles 122. Based on this configuration, the CD yarns separate the MD layers 102-1, 102-2 with upward binding (binding toward the paper side), e.g., exerting tension that tends to separate the paper-side layer 102-1 from the machine-side layer 102-2. The paper-side layer 102-1 maintains stability, and the separation of the MD layers 102-1, 102-2 provides stability for the paper-side layer 102-1 and increases the fabric openness, e.g., in the machine-side layer 102-2. As such, the CD yarns 106 maintain the structure of the press fabric 100 while contributing to a high void volume in the press fabric 100 by binding toward the paper side, in association with the lower yarn density toward the machine side as a result of the upward binding direction.

[0090] Yarns that perform a separation function, such as some of the CD yarns included in the press fabrics described herein, can be referred to as “separation yarns” and as constituting a “separation system.” Separation yarns / systems provide support in the press fabric to reduce compaction, thereby increasing the fabric's openness and, correspondingly, dewatering capability. In some cases, to separate two MD layers, a CD yarn can extend laterally between two MD layers, adjacent to multiple consecutive yarns of the MD layers. Separation by the CD yarns causes the MD layers to retain their open, stacked arrangement when pressure is applied, as opposed to collapsing. Further, to provide tension that corresponds to the separation force, a separation yarn can bind a single yarn of an MD layer. For example, referring to labels in FIG. 1C, the separation yarn can cross upward between MD yarn 102-1A and an adjacent second MD yarn 102-1B, pass over (e.g., outside) the second MD yarn 102-1B, and then cross downward between the second MD yarn 102-1B and an adjacent third MD yarn 102-1C. Based on this configuration, the separation yarn can exert an upward binding force (towards the paper side), to (i) separate the MD layers between which the separation yarn extends adjacent to multiple consecutive MD yarns, with (ii) a binding force towards the MD layer around which the separation yarn is woven.

[0091] In some implementations, as shown in FIGS. 1A-1C, the CD yarns 106 bind every sixth yarn of the paper-side layer 102-1 and extend adjacent to two consecutive yarns of the machine-side layer 102-2. However, other weave patterns of the CD yarns 106 are also within the scope of this disclosure, e.g., the CD yarns 106 can pass outside the paper-side layer 102-1 at a different rate and / or extend adjacent to a different number of consecutive yarns of the machine-side layer 102-2.

[0092] In some implementations, as shown in FIGS. 1A-1C, each of the first system of CD yarns 104 and the second system of CD yarns 106 is a three-end sequence. For example, along the machine direction, CD yarns 104 and CD yarns 106 alternate with one another. However, other weave patterns of the CD systems (e.g., number of ends in either or both systems, relative positioning between yarns of the CD systems, and / or the like) are also within the scope of this disclosure.

[0093] The CD yarns 104, 106 can be the same as or different from the MD yarns of the MD layers 102. For example, the CD yarns 104, 106 can include monofilament, plied monofilament, multifilament, and / or plied multifilament yarn. In some implementations, the CD yarns 104, 106 are composed of polyamide or another polymer material. In some implementations, at least some of the CD yarns 104, 106 are composed of a different material from the MD yarns. For example, in some implementations, at least some of the CD yarns 104, 106 are composed of an elastomer such as elastane, polyester, and / or polyurethane, and the MD yarns are composed of a lower-elasticity material such as polyamide. This configuration can cause the press fabric 100 to have a high elasticity, a characteristic that in some cases can provide improved papermaking performance. In some implementations, the weave patterns described herein provide relatively high elasticity, e.g., based on the presence of the separation yarns configured as described herein.

[0094] Accordingly, based on the relative yarn density ratios of the paper-side layer 102-1 and the machine-side layer 102-2, and based on the configuration of the CD yarns 106, the press fabric 100 can provide, in some implementations, improved water extraction and stability. The machine side of the press fabric 100 is relatively “open” so as to facilitate water transfer out of the machine side.

[0095] FIGS. 2A-2C illustrate another example of a press fabric 200. FIG. 2A is a side sectional view facing along the machine direction, FIG. 2B is a diagrammatic representation of the weave of the press fabric 200 facing along the CD axis from the left-most edge of FIG. 2A, and FIG. 2C is a perspective sectional view.

[0096] Like the press fabric 100, the press fabric 200 includes two MD layers 102-1, 102-2 which have characteristics as described for the corresponding layers of FIG. 1. Further, the press fabric 200 includes two systems of CD yarns. First and second systems of CD yarns 204, 206 have characteristics as described for the CD yarns 104, 106 of the press fabric 100, respectively, except as shown or described otherwise herein. For example, the CD yarns 204 of the first system (a double-layer sequence) bind together the paper-side layer 102-1 and the machine-side layer 102-2. The CD yarns 206 of the second system (a single-layer sequence) separate the MD layers 102-1, 102-2 with binding up toward the paper side, pass outside the paper-side layer 102-1, and remain inside the machine-side layer 102-2.

[0097] Whereas the systems of CD yarns 104, 106 of the press fabric 100 include three ends each, the systems of CD yarns 204, 206 of the press fabric 200 include four and two ends, respectively. Along the machine direction, the CD yarns follow a pattern of one CD yarn 206 followed by two CD yarns 204. The CD yarns 204 can bind every eighth yarn of the paper-side layer 102-1 and every fourth yarn of the machine-side layer 102-2, forming knuckles 220. The CD yarns 206 can bind every fourth yarn of the paper-side layer 102-1, forming knuckles 222.

[0098] FIGS. 3A-3C illustrate another example of a press fabric 300. FIG. 3A is a side sectional view facing along the machine direction, FIG. 3B is a diagrammatic representation of the weave of the press fabric 300 facing along the CD axis from the left-most edge of FIG. 3A, and FIG. 3C is a perspective sectional view.

[0099] The press fabric 300 includes two MD layers 102-1, 102-2 which have characteristics as described for the corresponding layers of press fabrics 100 and 200. Further, the press fabric 300 includes two systems of CD yarns. First and second systems of CD yarns 304, 306 have characteristics as described for the CD yarns 104, 106 of the press fabric 100, respectively, except as shown or described otherwise herein. For example, the CD yarns 304 of the first system (a double-layer sequence) bind together the paper-side layer 102-1 and the machine-side layer 102-2. The CD yarns 306 of the second system (a single-layer sequence) separate the MD layers 102-1, 102-2 with binding up toward the paper side, pass outside the paper-side layer 102-1, and remain inside the machine-side layer 102-2.

[0100] Each of the first and second systems of CD yarns 304, 306 is a four-end system. Along the machine direction, the CD yarns alternate between CD yarns 304 and CD yarns 306. The CD yarns 306 of the second system, to separate the MD layers 102-1, 102-2 with binding toward the paper side, extend adjacent to four consecutive yarns of the machine-side layer 102-2 and then pass outside a single yarn of the paper-side layer 102-1. The CD yarns 304 can bind every eighth yarn of the paper-side layer 102-1 and every fourth yarn of the machine-side layer 102-2, forming knuckles 320. The CD yarns 306 can bind every eighth yarn of the paper-side layer 102-1, forming knuckles 322.

[0101] The press fabrics 200 and 300 can provide the advantages discussed for the press fabric 100. For example, because the machine-side layers 102-2 of the press fabrics 200, 300 include fewer yarns than the paper-side layers 102-1, the press fabrics 200, 300 have high permeability toward the machine side while maintaining their strength to support paper sheets on the paper side. In some implementations, the permeability is increased by the separation (with binding toward the paper side) provided by the second systems of CD yarns 206, 306.

[0102] The scope of this disclosure is not limited to two-layer fabrics. In some implementations, the press fabric has three, four, or more layers.

[0103] For example, FIGS. 4A-4C illustrate an example of a press fabric 400 having three layers of MD yarn. FIG. 4A is a side sectional view facing along the machine direction, FIG. 4B is a diagrammatic representation of the weave of the press fabric 400 facing along the CD axis from the left-most edge of FIG. 4A, and FIG. 4C is a perspective sectional view.

[0104] The press fabric 400 includes a paper-side layer 402-1, a machine-side layer 402-3, and an intermediate layer 402-2. In some implementations, a press fabric having four or more layers of MD yarn includes multiple intermediate layers 402-2 stacked on one another between the paper-side layer 402-1 and the machine-side layer 402-3.

[0105] In some implementations, the paper-side layer 402-1 has a higher number of yarns per unit length (a higher yarn density) along the cross-machine direction than the machine-side layer 402-3. For example, the press fabric 400 has a 2:1 yarn density ratio between the paper-side layer 402-1 and the machine-side layer 402-3. Alternating yarns of the paper-side layer 402-1 are aligned with (e.g., disposed above) a corresponding yarn of the machine-side layer 402-3 or are above a position where no yarn of the machine-side layer 402-3 is present (misaligned with the yarns of the machine-side layer 402-3), corresponding to a void. As discussed with respect to the two-layer fabrics of FIGS. 1A to 3C, the lower number of yarns of the machine-side layer 402-3 can provide a higher permeability / openness, corresponding to improved drainage and dewatering by the press fabric 400. Further, as discussed with respect to the two-layer yarns, the density ratio is not limited to 2:1 but rather, in some implementations, can be 3:1, 4:1, 3:2, 5:2, or another density ratio.

[0106] In some implementations, in a fabric having three or more MD layers (e.g., any press fabric, as described herein, having three or more MD layers), at least one of the intermediate layers has fewer yarns per unit length along the cross-machine direction than the paper-side layer. For example, at least one of the intermediate layers (e.g., all intermediate layers) can have a yarn density equal to a yarn density of the machine-side layer. In some implementations, at least one of the intermediate layers has a yarn density less than that of the paper-side layer and more than that of the machine-side layer. For example, yarn density ratios between the paper-side layer, at least one intermediate layer, and the machine-side layer can be 2:1:1, 3:1:1. 3:2:1, 4:1:1, 4:2:1, 3:2:1, etc. As shown in FIGS. 4A and 4C, the intermediate layer 402-2 has a yarn density matching that of the machine-side layer 402-3. Yarns of the intermediate layer 402-2 are aligned with (disposed above) corresponding yarns of the machine-side layer 402-3. Correspondingly, the paper-side layer 402-1 has a 2:1 yarn density ratio with the intermediate layer 402-3. Alternating yarns of the paper-side layer 402-1 are aligned with (e.g., disposed above) a corresponding yarn of the intermediate layer 402-2 or are above a position where no yarn of the intermediate layer 402-2 is present (misaligned with the yarns of the intermediate layer 402-2), corresponding to a void.

[0107] It will be understood that the yarn density relationship between the paper-side layer, the intermediate layer(s), and the machine-side layer is not limited to this example. In some implementations, at least one intermediate layer has a number of yarns per unit length in the cross-machine direction that matches that of the paper-side layer, e.g., has a yarn density ratio of 1:1 with the paper-side layer. Instead, or additionally, at least one intermediate layer can have a number of yarns per unit length in the cross-machine direction that is less than that of the paper-side layer and more than that of the machine-side layer, e.g., has a yarn density ratio of less than 1 with the paper-side layer and more than 1 with the machine-side layer. For example, yarn density ratios between the paper-side layer, at least one intermediate layer, and the machine-side layer can be 2:2:1, 3:2:1, 4:2:1, or 5:3:1, to provide several non-exhaustive examples. When there is more than one intermediate layer, different intermediate layers can have the same or different yarn densities. For example, a first intermediate layer can have a yarn density matching that of the paper-side layer, a second intermediate layer can have a yarn density in-between that of the paper-side layer and that of the machine-side layer, and / or a third intermediate layer can have a yarn density matching that of the machine-side layer. For example, for a fabric with four layers of MD yarns, the yarn density ratio, proceeding from the paper-side layer to the machine-side layer, can be 2:1:1:1, 3:1:1:1, 4:1:1:1, 2:2:1:1, 3:2:1:1, 4:2:1:1, 4:2:2:1, etc.

[0108] In some implementations in which there is more than one intermediate layer, a first intermediate layer that is closer to the paper side has a higher yarn density than a second intermediate layer that is closer to the machine side. This configuration can facilitate effective drainage and dewatering by the press fabric (based on the higher permeability / openness toward the machine side).

[0109] In addition to the MD layers, the press fabric 400 includes two systems of CD yarns. Yarns 404 of a first system of CD yarns bind together the paper-side layer 402-1 and the machine-side layer 402-3 with a four-end triple-layer sequence. The yarns 404 pass outside the paper-side layer 402-1 and pass outside the machine-side layer 402-3. In some implementations, the yarns 404 cross between aligned yarns of the intermediate layer 402-2 and the machine-side layer 402-3. In some implementations, in the sequence shown in FIGS. 4A-4C, the yarns 404 pass outside and bind a single yarn of the paper-side layer 402-1 (forming a knuckle 420-1) before extending back to inside the paper-side layer 402-1. In some implementations, the yarns 404 pass outside and bind a single yarn of the machine-side layer 402-3 (forming a knuckle 420-2) before extending back to inside the paper-side layer 402-3.

[0110] Yarns 406 of a second system of CD yarns form a single-layer sequence. The yarns 406 pass outside the paper-side layer 402-1 and remain inside the machine-side layer 402-3. For example, in the cross-machine direction, the yarns 406 pass outside the paper-side layer 402-1 (e.g., pass outside a single yarn of the paper-side layer 402-1), cross between aligned yarns of the layers 402-1 and 402-2, and extend adjacent to multiple consecutive yarns of the intermediate layer 402-2 (in the example of the press fabric 400, adjacent to four consecutive yarns of the intermediate layer 402-2, without being limited to that number in other implementations), before again passing outside the paper-side layer 402-1. When multiple intermediate layers are present, in some implementations, the yarns 406 extend adjacent to multiple consecutive yarns of an intermediate layer that is closest to the paper-side layer, among the multiple intermediate layers (an uppermost intermediate layer). When multiple intermediate layers are present, in some implementations, the yarns 406 cross between the paper-side layer and the uppermost intermediate layer.

[0111] In some implementations, the yarns 406 remain on the paper side of the intermediate layer 402-2, e.g., do not cross between the intermediate layer 402-2 and the machine-side layer 402-3 and / or do not pass to a machine side of the intermediate layer 402-2. When multiple intermediate layers are present, in some implementations, the yarns 406 remain on the paper side of the multiple intermediate layers. In some implementations, these configurations contribute to a higher permeability / openness toward the machine side of the press fabric 400, e.g., because the press fabric 400 includes voids, on the machine side of the intermediate layer(s), that would otherwise be filled by the yarns 406. However, other weave patterns of the yarns 406 are within the scope of this disclosure.

[0112] Based on the foregoing configuration, the yarns 406 separate the paper-side layer 402-1 from the intermediate layer 402-2 with binding upward toward the paper side. As such, the void volume of the press fabric 400, and / or the permeability / openness toward the machine side of the press fabric 400, is increased, promoting drainage and dewatering by the press fabric 400. When multiple intermediate layers are present, in some implementations, the yarns 406 separate the paper-side layer 402-1 from an uppermost intermediate layer.

[0113] Each of the first and second systems of CD yarns 404, 406 includes four ends. Along the machine direction, CD yarns 404 alternate with CD yarns 406, as shown in FIG. 4B. The yarns of the press fabric 400 can have composition(s) as described for the yarns of the press fabric 100. The CD yarns 404 can bind every eighth yarn of the paper-side layer 402-1 and every fourth yarn of the machine-side layer 402-3. The CD yarns 406 can bind every eight yarn of the paper-side layer 402-1, forming knuckles 422.

[0114] In some implementations, a press fabric includes three systems of CD yarns. For example, a first system can bind together the paper-side and machine-side layers; a second system can separate the paper-side layer from intermediate layer(s); and a third system can separate intermediate layer(s) from the machine-side layer.

[0115] For example, FIGS. 5A-5C illustrate an example of a press fabric 500 including three MD layers 402-1, 402-2, 402-3 and three systems of CD yarns. FIG. 5A is a side sectional view facing along the machine direction, FIG. 5B is a diagrammatic representation of the weave of the press fabric 500 facing along the CD axis from the left-most edge of FIG. 5A, and FIG. 5C is a perspective sectional view.

[0116] The three MD layers 402-1, 402-2, 402-3 can have characteristics as described for the corresponding layers of the press fabric 400. A first system of CD yarns 504, which binds together the paper-side layer 402-1 and the machine-side layer 402-3, has characteristics as described for the first system of CD yarns 404, e.g., forms a triple-layer sequence with four ends and passes outside each of the paper-side layer 402-1 and machine-side layer 402-3.

[0117] A second system of CD yarns 506, forming a single-layer sequence, is configured to separate the paper-side layer 402-1 and the intermediate layer 402-2 with binding toward the paper side. The second system of CD yarns 506 passes outside the paper-side layer 402-1 and remains inside the machine-side layer 402-3. In some implementations, the second system of CD yarns 506 remains on a paper side of the intermediate layer 402-2. The CD yarns 506 extend adjacent to multiple consecutive yarns of the intermediate layer 402-2, e.g., two consecutive yarns as shown in FIGS. 5A-5C. The CD yarns 506 can have characteristics as described for the CD yarns 406 of the press fabric 400, except as shown otherwise or described otherwise herein. As discussed in reference to FIGS. 4A-4C, the separation provided between the paper-side layer 402-1 and the intermediate layer 402-2 with upward binding can increase the void volume of the press fabric 500 and / or the permeability / openness toward the machine side of the press fabric 500.

[0118] A third system of CD yarns 508 is configured to separate the intermediate layer 402-2 and the machine-side layer 402-3 with binding toward the paper side (up into the intermediate layer 402-2). The CD yarns 508 can have composition(s) as described for the CD yarns of the press fabrics 100, 200, 300, and 400. The CD yarns 508 form a single-layer sequence that remains inside the machine-side layer 402-3, which can contribute to an increased void volume of the press fabric 500 and / or the permeability / openness toward the machine side of the press fabric 500. The CD yarns 508 can cross between aligned yarns of the intermediate layer 402-2 and the paper-side layer 402-1, e.g., at positions where the CD yarns 508 pass above single yarns of the intermediate layer 402-2. When multiple intermediate layers are included, in some implementations, the CD yarns 508 cross between aligned yarns of an intermediate layer closest to the machine-side layer 402-3 (a lowest intermediate layer) and an adjacent intermediate layer (a second-lowest intermediate layer), e.g., at positions where the CD yarns 508 pass above single yarns of the lowest intermediate layer.

[0119] The CD yarns 508 can extend adjacent to multiple consecutive yarns of the machine-side layer 402-3 and the intermediate layer 402-2 between the machine-side layer 402-3 and the intermediate layer 402-2, so as to separate the machine-side layer 402-2 from the intermediate layer 402-2. For example, as shown in FIGS. 5A and 5C, the CD yarns 508 can extend adjacent to three consecutive yarns of the machine-side layer 402-3.

[0120] Because the CD yarns 508 separate the intermediate layer 402-2 from the machine-side layer 402-3 by binding upward, toward the paper side (e.g., by forming knuckles on top sides of the yarns of the intermediate layer 402-2), in some implementations the CD yarns 508 contribute to increased void volume in the press fabric 500 and / or increased permeability / openness toward the machine side of the press fabric 500, improving drainage and dewatering by the press fabric 500.

[0121] The first system of CD yarns 504 includes four ends, and the second and third systems of CD yarns 506, 508 each include two ends. Along the machine direction, CD yarns 504, 506, 508 follow a BACABACA pattern, where “A” is the CD yarns 504, “B” is the CD yarns 506, and “C” is the CD yarns 508. This configuration is shown in FIG. 5B. The CD yarns 504 can bind every eighth yarn of the paper-side layer 402-1 and every fourth yarn of the machine-side layer 402-3, forming knuckles 520. The CD yarns 506 can bind every fourth yarn of the paper-side layer 402-1, forming knuckles 522. The CD yarns 508 can bind every fourth yarn of the intermediate layer 402-2, forming knuckles 524. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 504, 506, 508.

[0122] In some implementations, a system of CD yarns that separates the machine-side layer from one or more intermediate layers is configured differently from the third system of CD yarns of the press fabric 500. For example, the yarns of the system can form a double-layer sequence (or other non-single-layer sequence), and / or the yarns can pass outside the paper-side layer.

[0123] In comparison to the press fabric 400, although the press fabric 500 includes an additional system of CD yarns, the systems of CD yarns 506 and 508 are two-end systems, whereas the system of CD yarns 406 is a four-end system. As such, the void volume provided by the press fabric 500 can be equal to or greater than the void volume provided by the press fabric 400.

[0124] FIGS. 6A-6C illustrate another example of a press fabric 600 including three MD layers 402-1, 402-2, 402-3 and three systems of CD yarns. FIG. 6A is a side sectional view facing along the machine direction, FIG. 6B is a diagrammatic representation of the weave of the press fabric 600 facing along the CD axis from the left-most edge of FIG. 6A, and FIG. 6C is a perspective sectional view.

[0125] The three MD layers 402-1, 402-2, 402-3 can have characteristics as described for the corresponding layers of the press fabric 400. A first system of CD yarns 604, which binds together the paper-side layer 402-1 and the machine-side layer 402-3, has characteristics as described for the first system of CD yarns 404, e.g., forms a triple-layer sequence with four ends and passes outside each of the paper-side layer 402-1 and machine-side layer 402-3.

[0126] A second system of CD yarns 606, forming a single-layer sequence, is configured to separate the paper-side layer 402-1 and the intermediate layer 402-2 with binding toward the paper side. The second system of CD yarns 606 passes outside the paper-side layer 402-1 and remains inside the machine-side layer 402-3. In some implementations, the second system of CD yarns 606 remains on a paper side of the intermediate layer 402-2. The CD yarns 606 extend adjacent to multiple consecutive yarns of the intermediate layer 402-2, e.g., four consecutive yarns as shown in FIGS. 6A-6C. The CD yarns 606 can have characteristics as described for the CD yarns 406 and / or 506 of the press fabrics 400, 500, except as shown or described otherwise herein.

[0127] A third system of CD yarns 608 is configured to separate the intermediate layer 402-2 and the machine-side layer 402-3 with binding toward the paper side (up into the paper-side layer 402-1). The CD yarns 608 can have composition(s) as described for the CD yarns of the press fabrics 100, 200, 300, 400, and 500. The CD yarns 608 form a double-layer sequence that passes outside the paper-side layer 402-1 and remains inside the machine-side layer 402-3, which can contribute to an increased void volume of the press fabric 600 and / or increased permeability / openness toward the machine side of the press fabric 600 towards the machine side of the press fabric 600. For example, the press fabric 600 is relatively denser towards its paper side and relatively less dense towards its machine side.

[0128] The CD yarns 608 can cross between aligned yarns of the machine-side layer 402-3 and the intermediate layer 402-2 and between aligned yarns of the intermediate layer 402-2 and the paper-side layer 402-1. The CD yarns 608 can pass outside single yarns of the paper-side layer 402-1, e.g., so as to bind the single yarns to exert a separating binding force toward the paper side. The CD yarns 608 can extend adjacent to multiple consecutive yarns of the machine-side layer 402-3 and the intermediate layer 402-2 between the machine-side layer 402-3 and the intermediate layer 402-2, so as to separate the machine-side layer 402-2 from the intermediate layer 402-2. For example, as shown in FIGS. 6A and 6C, the CD yarns 608 can extend adjacent to two consecutive yarns of the machine-side layer 402-3. Based on this configuration, the intermediate layer 402-2 can be separated from the machine-side layer 402-3 to increase a void volume in the press fabric 600 and maintain high permeability / openness at toward the machine-side layer 402-3, e.g., at the machine-side layer 402-3.

[0129] The first system of CD yarns 604 includes four ends, and the second and third systems of CD yarns 606, 608 each include two ends. Along the machine direction, CD yarns 604, 606, 608 follow a BACABACA pattern, where “A” is the CD yarns 604, “B” is the CD yarns 606, and “C” is the CD yarns 508. This configuration is shown in FIG. 6B. The CD yarns 604 can bind every eighth yarn of the paper-side layer 402-1 and every fourth yarn of the machine-side layer 402-3, forming knuckles 620. The CD yarns 606 and 608 can bind every eighth yarn of the paper-side layer 402-1, forming knuckles 622, 624. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 604, 606, 608.

[0130] Compared to the press fabric 500, the press fabric 600 may exhibit increased stability against compaction between the paper-side layer 402-1 and the intermediate layer 402-2, due to the longer extension of the CD yarns 606 in comparison to the CD yarns 506. However, the press fabric 600 may have less-stable separation of the machine-side layer 402-3 from the intermediate layer 402-2 compared to the press fabric 500, due to the difference in configuration between the CD yarns 508 and 608.

[0131] It will be understood that other configurations of the third system of CD yarns are also within the scope of this disclosure. For example, in some implementations that include multiple intermediate layers, a system of CD yarns that separates the lowest intermediate layer from the machine-side layer is woven around yarns of another intermediate layer, e.g., the second-lowest intermediate layer or higher intermediate layer.

[0132] FIGS. 7A-7C illustrate another example of a press fabric 700 having three MD layers. FIG. 7A is a side sectional view facing along the machine direction, FIG. 7B is a diagrammatic representation of the weave of the press fabric 700 facing along the CD axis from the left-most edge of FIG. 7A, and FIG. 7C is a perspective sectional view.

[0133] The MD layers 402-1, 402-2, 402-3 and the systems of CD yarns 704, 706 have generally the same characteristics as described for the corresponding layers / yarns of the press fabric 400. However, while the second system of CD yarns 406 is a four-end system having CD yarns 406 that bind every eighth yarn of the paper-side layer 402-1, the second system of CD yarns 706 is a two-end system having CD yarns 706 that bind every fourth yarn of the paper-side layer 402-1, forming knuckles 722. The CD yarns 706 extend adjacent to two consecutive yarns of the intermediate layer 402-2 between the intermediate layer 402-2 and the paper-side layer 402-1, to separate the intermediate layer 402-2 and the paper-side layer 402-1 with a binding force toward the paper side. Accordingly, the press fabric 700 can maintain its openness, promoting drainage and dewatering. The press fabric 700 can also provide the other advantages discussed with respect to the press fabric 400.

[0134] As shown in FIG. 7B, along the machine direction, each CD yarn 706 is followed by two CD yarns 704 in a repeating pattern. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 704, 706.

[0135] The scope of this disclosure is not limited to press fabrics having two or three MD layers. In some implementations, a press fabric as described herein includes four or more MD layers. For example, FIGS. 8A-8E illustrate an example of a press fabric 800 having four MD layers. FIG. 8A is a side sectional view facing along the machine direction; FIGS. 8B-8C are top and bottom views, respectively; FIG. 8D is a perspective sectional view; and FIG. 8E is a side sectional view facing along the cross-machine direction. In FIGS. 8A-8E, reference letter “A” indicates a common position of the pattern of the press fabric.

[0136] Of four MD layers 802 in the press fabric 800, layer 802-1 is a paper-side layer, layer 802-4 is a machine-side layer, and layers 802-2, 802-3 are intermediate layers. These layers can have characteristics as described for the corresponding layers of the press fabrics 100, 200, 300, 400, 500, 600, and 700. For example, a yarn density of the paper-side 802-1 can be higher than a yarn density of the machine-side layer 802-4 and higher than yarn densities of at least one of, or all of, the intermediate layers 802-2, 802-3. In some implementations, as shown in FIGS. 8A-8E, the intermediate layers 802-2, 802-3 and the machine-side layer 802-4 have a same yarn density that is less than the yarn density of the paper-side layer 802-1 (in this example, a 2:1 yarn density ratio).

[0137] The press fabric 800 further includes four systems of CD yarns. A first system of CD yarns 804 (of which only one yarn is labeled for clarity of illustration) binds together the paper-side layer 802-1 and the machine-side layer 802-4, e.g., forms a four-layer sequence, with four ends, that binds yarns of both the paper-side layer 802-1 and the machine-side layer 802-4 and passes outside both the paper-side layer 802-1 and the machine-side layer 802-4, forming knuckles 820.

[0138] Three separation systems of CD yarns 806, 808, 810 are included in the press fabric 800. The three systems of CD yarns 806, 808, 810 each form a two end, double-layer sequence and remain inside the machine-side layer 802-4 to contribute to increased permeability / openness at the machine side of the press fabric 800. The CD yarns 806, 808, 810 can have composition(s) as described for the CD yarns of the press fabrics 100, 200, 300, 400, 500, 600, and 700.

[0139] A first system of CD yarns 806 separates the paper-side layer 802-1 and the adjacent upper intermediate layer 802-2, binding yarns of the paper-side layer 802-1 (forming knuckles 822) and remaining toward a paper side of the intermediate layer 802-2. A second system of CD yarns 808 separates the two intermediate layers 802-2, 802-3, binding yarns of the upper intermediate layer 802-2 (forming knuckles 824, shown in FIG. 8D) and remaining toward a paper side of the lower intermediate layer 802-3. A third system of CD yarns 810 separates the lower intermediate layer 802-3 and the machine-side layer 802-4, binding yarns of the lower intermediate layer 802-3 (forming knuckles 826) and remaining toward a paper side of the machine-side layer 802-4 (e.g., remaining inside the machine-side layer 802-4). Based on these weave patterns, each system of CD yarns 806, 808, 810 performs its separation function with an upward binding force, contributing to an increased permeability / openness toward the machine side of the press fabric 800 to promote drainage and dewatering.

[0140] Along the machine direction, CD yarns 804, 806, 808, 810 follow an ABACADABACAD pattern, where “A” is the CD yarns 804, “B” is the CD yarns 806, “C” is the CD yarns 808, and “D” is the CD yarns 810. The CD yarns 804 can bind every twelfth yarn of the paper-side layer 802-1 and every sixth yarn of the machine-side layer 802-4. The CD yarns 806 can bind every fourth yarn of the paper-side layer 802-1, passing adjacent to two consecutive yarns of the upper intermediate layer 802-2 between the paper-side layer 802-1 and the upper intermediate layer 802-2. The CD yarns 808 can bind every sixth yarn of the upper intermediate layer 802-2, passing adjacent to five consecutive yarns of the intermediate layers 802-2, 802-3 between the intermediate layers 802-2, 802-3. The CD yarns 810 can bind every sixth yarn of the lower intermediate layer 802-3, passing adjacent to five consecutive yarns of the lower intermediate layer 802-3 and the machine-side layer 802-4 between the lower intermediate layer 802-3 and the machine-side layer 802-4. Other patterns are also within the scope of this disclosure and can provide the binding and separation effects provided by the CD yarns 806, 808, 810.

[0141] FIG. 9 illustrates another example of a press fabric 900. The press fabric 900 includes three MD layers 402-1, 402-2, 402-3. Further, the press fabric 900 includes two systems of binding yarns. A first system of CD yarns 904-1 (a three-end sequence) binds the machine-side layer 402-3 to the intermediate layer 402-2, passing outside the machine-side layer 402-3 and remaining toward the machine side of the paper-side layer 402-1. A second system of CD yarns 904-2 (a two-end sequence) binds the paper-side layer 402-1 to the intermediate layer 402-2, passing outside the paper-side layer 402-1 and remaining toward the paper side of the machine-side layer 402-3. The two systems of CD yarns 904-1, 904-2 jointly bind the press fabric 900 together. The yarns of the press fabric 900 can have characteristics as described for corresponding yarns of the preceding examples.

[0142] The press fabric 900 also includes a separation system of CD yarns 906, which form a two-end, single-layer sequence that passes outside the paper-side layer 402-1 and remains towards a paper side of the intermediate layer 402-2. The CD yarns 906 extend adjacent to multiple consecutive yarns of the intermediate layer 402-2, e.g., three consecutive yarns as shown in FIG. 9.

[0143] The weave pattern of the press fabric 900 provides improved dewatering. For example, the CD yarns 906 separate the MD layers 402-1, 402-2 with an upward binding force that contributes to higher permeability / openness towards the machine side of the press fabric 900. The arrangement of the CD yarns 906 on the paper side of the intermediate layer 402-2 (e.g., not extending in the machine-side layer 402-3) also contributes to higher permeability / openness in the machine-side layer 402-3. The higher yarn density of the paper-side layer 402-1 compared to the machine-side layer 402-3 also promotes water transfer to and out of the machine-side layer 402-3, to allow the press fabric 900 to better absorb and remove water.

[0144] FIG. 10 illustrates another example of a press fabric 1000. The press fabric 1000 includes four MD layers 1002-1, 1002-2, 1002-3, 1002-4. A paper-side layer 1002-1 has a yarn density ratio, with respect to upper and lower intermediate layers 1002-2, 1002-3 and a machine-side layer 1004-4, of 3:1. Further, the press fabric 1000 includes two systems of binding yarns. A first system of CD yarns 1004-1 performs a binding function, adding stability and reinforcing the structural integrity of the paper side of the press fabric 1000. A second system of CD yarns 1004-2 binds the paper-side layer 1002-1 to the upper intermediate layer 1002-2, passing outside the paper-side layer 1002-1 and remaining toward the paper side of the lower intermediate layer 1002-3. The arrangement of the CD yarns 1004-1, 1004-2 primarily at the paper side of the press fabric 1000 (e.g., remaining toward a paper side of the lower intermediate layer 1004-3) can contribute to increased permeability / openness toward the machine side of the press fabric 1000, promoting dewatering. The yarns of the press fabric 1000 can have characteristics as described for corresponding yarns of the preceding examples.

[0145] The press fabric 1000 also includes three separation systems of CD yarns 1006, 1008, 1010. The CD yarns 1006, which form a three-layer, two-end system, bind the machine-side layer 1002-4 (e.g., bind downward) and extend between the paper-side layer 1002-1 and the upper intermediate layer 1002-2 for three consecutive yarns of the upper intermediate layer 1002-2. The CD yarns 1008, which form a double-layer, two-end sequence, bind the machine-side layer 1002-4 (e.g., bind downward) and extend between the intermediate layers 1002-2, 1002-3 for three consecutive yarns of the intermediate layers 1002-2, 1002-3. The CD yarns 1010, which form a three-layer, two-end sequence, bind the paper-side layer 1002-1 (e.g., bind upward), extending between the lower intermediate layer 1002-3 and the machine-side layer 1002-4 for three consecutive yarns of the lower intermediate layer 1002-3. This weave arrangement can provide high permeability at the machine-side layer 1002-4, promoting water transfer through the machine-side layer 1002-4 and out of the press fabric 1000.

[0146] FIG. 11 illustrates another example of a press fabric 1100. The press fabric 1100 includes four MD layers 802-1, 802-2, 802-3, 802-4 as described with respect to FIGS. 8A-8E.

[0147] The press fabric 1100 includes two systems of binding yarns. A first system of CD yarns 1104-1 binds the paper-side layer 802-1 to the lower intermediate layer 802-3. A second system of CD yarns 1104-2 binds the paper-side layer 1002-1 to the upper intermediate layer 802-2. Along the cross-machine direction, the CD yarns 1104-2 alternate between binding on the upper intermediate layer 802-2 (passing to the machine side of the upper intermediate layer 802-2) and passing between aligned yarns of the paper-side layer 802-1 and the upper intermediate layer 802-2). The arrangement of the CD yarns 1104-1, 1104-2 primarily at the paper side of the press fabric 1100 (e.g., with the CD yarns 1104-1 remaining toward a paper side of the lower intermediate layer 802-3 and the CD yarns 1104-2 remaining toward a paper side of the machine-side layer 802-4) can contribute to increased permeability / openness toward the machine side of the press fabric 1100, promoting dewatering. The yarns of the press fabric 1000 can have characteristics as described for corresponding yarns of the preceding examples.

[0148] The press fabric 1100 also includes three separation systems of CD yarns 1106, 1108, 1110. The CD yarns 1106, which form a three-layer, two-end system, bind the machine-side layer 802-4 (e.g., bind downward) and extend between the paper-side layer 802-1 and the upper intermediate layer 802-2 for three consecutive yarns of the upper intermediate layer 802-2. The CD yarns 1108, which form a double-layer, two-end sequence, bind the machine-side layer 802-4 (e.g., bind downward) and extend between the intermediate layers 802-2, 802-3 for three consecutive yarns of the intermediate layers 802-2, 802-3. The CD yarns 1110, which form a three-layer, two-end sequence, bind the paper-side layer 802-1 (e.g., bind upward), extending between the lower intermediate layer 802-3 and the machine-side layer 802-4 for three consecutive yarns of the lower intermediate layer 802-3. This weave arrangement can provide high permeability at the machine-side layer 802-4, promoting water transfer through the machine-side layer 802-4 and out of the press fabric 1100.

[0149] FIG. 12 illustrates another example of a press fabric 1200. The press fabric 1200 includes four MD layers 1202-1, 1202-2, 1202-3, 1202-4. Yarn density ratios of a paper-side layer 1202-1, upper and lower intermediate layers 1202-2, 1202-3, and a machine-side layer 1204-4 are 2:2:1:1. Further, the press fabric 1200 includes two systems of binding yarns. A first system of CD yarns 1204-1 performs a binding function, adding stability and reinforcing the structural integrity of the paper side of the press fabric 1200. A second system of CD yarns 1204-2 binds the paper-side layer 1202-1 to the upper intermediate layer 1202-2, passing outside the paper-side layer 1202-1 and remaining toward the paper side of the lower intermediate layer 1202-3. The arrangement of the CD yarns 1204-1, 1204-2 primarily at the paper side of the press fabric 1200 (e.g., remaining toward a paper side of the lower intermediate layer 1204-3) can contribute to increased permeability / openness toward the machine side of the press fabric 1200, promoting dewatering. The yarns of the press fabric 1200 can have characteristics as described for corresponding yarns of the preceding examples.

[0150] The press fabric 1200 also includes three separation systems of CD yarns 1206, 1208, 1210. The CD yarns 1206, which form a three-layer, two-end system, bind the machine-side layer 1202-4 (e.g., bind downward) and extend between the paper-side layer 1202-1 and the upper intermediate layer 1202-2 for five consecutive yarns of the upper intermediate layer 1202-2. The CD yarns 1208, which form a double-layer, two-end sequence, bind the machine-side layer 1202-4 (e.g., bind downward) and extend between the intermediate layers 1202-2, 1202-3 for three consecutive yarns of the lower intermediate layer 1202-3. The CD yarns 1210, which form a three-layer, two-end sequence, bind the paper-side layer 1202-1 (e.g., bind upward), extending between the lower intermediate layer 1202-3 and the machine-side layer 1202-4 for three consecutive yarns of the lower intermediate layer 1202-3. This weave arrangement can provide high permeability at the machine-side layer 1202-4, promoting water transfer through the machine-side layer 1202-4 and out of the press fabric 1200.

[0151] FIG. 13 illustrates another example of a press fabric 1300. The press fabric 1300 includes four MD layers 1302-1, 1302-2, 1302-3, 1302-4. Yarn density ratios of a paper-side layer 1302-1, upper and lower intermediate layers 1302-2, 1302-3, and a machine-side layer 1302-4 are 3:3:1:1. Further, the press fabric 1300 includes two systems of binding yarns. A first system of CD yarns 1304-1 performs a binding function, adding stability and reinforcing the structural integrity of the paper side of the press fabric 1300. A second system of CD yarns 1304-2 binds the paper-side layer 1302-1 to the upper intermediate layer 1302-2, passing outside the paper-side layer 1302-1 and remaining toward the paper side of the lower intermediate layer 1202-3. The arrangement of the CD yarns 1304-1, 1304-2 primarily at the paper side of the press fabric 1300 (e.g., remaining toward a paper side of the lower intermediate layer 1304-3) can contribute to increased permeability / openness toward the machine side of the press fabric 1300, promoting dewatering. The yarns of the press fabric 1300 can have characteristics as described for corresponding yarns of the preceding examples.

[0152] The press fabric 1300 also includes three separation systems of CD yarns 1306, 1308, 1310. The CD yarns 1306, which form a three-layer, two-end system, bind the machine-side layer 1302-4 (e.g., bind downward) and extend between the paper-side layer 1302-1 and the upper intermediate layer 1302-2 for seven consecutive yarns of the upper intermediate layer 1302-2. The CD yarns 1308, which form a double-layer, two-end sequence, bind the machine-side layer 1302-4 (e.g., bind downward) and extend between the intermediate layers 1302-2, 1302-3 for three consecutive yarns of the lower intermediate layer 1302-3. The CD yarns 1310, which form a three-layer, two-end sequence, bind the paper-side layer 1302-1 (e.g., bind upward), extending between the lower intermediate layer 1302-3 and the machine-side layer 1302-4 for three consecutive yarns of the lower intermediate layer 1302-3. This weave arrangement can provide high permeability at the machine-side layer 1302-4, promoting water transfer through the machine-side layer 1302-4 and out of the press fabric 1300.

[0153] FIG. 14 illustrates another example of a press fabric 1400. The press fabric 1400 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1400 includes a system of binding yarns 1404 that binds the paper-side layer 402-1 to the machine-side layer 402-3, passing outside the paper-side layer 402-1 and the machine-side layer 402-3. The press fabric 1400 also includes a separation system of CD yarns 1406. The CD yarns 1406 form a single-layer, two-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the paper-side layer 402-1. The CD yarns 1406 separate the MD layers 402-1, 402-2 to improve permeability and openness towards the machine side of the press fabric 1400.

[0154] FIG. 15 illustrates another example of a press fabric 1500. The press fabric 1500 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1500 includes a system of binding yarns 1504 that binds the paper-side layer 402-1 to the machine-side layer 402-3, passing outside the paper-side layer 402-1 and the machine-side layer 402-3. The press fabric 1500 also includes a separation system of CD yarns 1506. The CD yarns 1506 form a double-layer, four-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the intermediate layer 402-2 and the machine-side layer 402-3 for three consecutive yarns of each of the intermediate layer 402-1 and the machine-side layer 402-3. By separating the intermediate layer 402-2 and the machine-side layer 402-3 with upward binding, the CD yarns can increase permeability and openness of the press fabric 1500 at the machine side.

[0155] FIG. 16 illustrates another example of a press fabric 1600. The press fabric 1600 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1600 includes a binder system of CD yarns 1604. The CD yarns 1604 bind the paper-side layer 402-1 and the machine-side layer 402-3, passing outside the paper-side layer 402-1 and the machine-side layer 402-3. The CD yarns 1604-2 bind the intermediate layer 402-2 and the machine-side layer 402-3, passing outside the machine-side layer 402-3, remaining inside the paper-side layer 402-1, and extending between the intermediate layer 402-2 and the paper-side layer 402-2. The press fabric 1600 also includes three separation systems of CD yarns 1606, 1608, 1610. The CD yarns 1606 form a single-layer, two-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the paper-side layer 402-1. The CD yarns 1608 form a double-layer, two-end system and bind the paper-side layer 402-1 (e.g., bind upward), extending between the intermediate layer 402-2 and the machine-side layer 402-3 for four consecutive yarns of each of the intermediate layer 402-2 and the machine-side layer 402-3. The CD yarns 1610 form a double-layer, two-end system and bind the machine-side layer 402-3, extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the intermediate layer 402-2. By separating the paper-side layer 402-1 and the intermediate layer 402-2 (for the CD yarns 1606, 1610) or the intermediate layer 402-2 and the machine-side layer 402-3 (for the CD yarns 1608) with a force toward the paper-side layer 402-1, the CD yarns 1606, 1608 contribute to increased permeability / openness toward the machine side of the press fabric 1600, promoting dewatering.

[0156] FIG. 17 illustrates another example of a press fabric 1700. The press fabric 1700 includes three MD layers 402-1, 402-2, 402-3. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. A binder system of CD yarns 1704 binds the paper-side layer 402-1 and the machine-side layer 402-3. A separation system of CD yarns 1706 forms a double-layer, four-end system, extending between the intermediate layer 402-2 and the machine-side layer 402-3 for four consecutive yarns of each of the intermediate layer 402-2 and the machine-side layer 402-3. The CD yarns 1707 form a double-layer, four-end system and bind the paper-side layer 402-1 to bind upward. This weave arrangement can provide high permeability at the machine-side layer 402-3, promoting water transfer through the machine-side layer 402-3 and out of the press fabric 1700.

[0157] FIG. 18 illustrates another example of a press fabric 1800. Yarn density ratios of a paper-side layer 402-1, an intermediate layer 402-2, and a machine-side layer 402-3 are 2:1:1. The press fabric 1800 includes a binder system of CD yarns 1804 that binds the paper-side layer 402-1 and the machine-side layer 402-3. The press fabric 1800 also includes a separation system of CD yarns 1806, which form a double-layer, four-end system that binds on the paper-side layer 402-1 to bind upward. The CD yarns 1806 perform a dual separation function, extending between the paper-side layer 402-1 and the intermediate layer 402-2 for three consecutive yarns of the paper-side layer 402-1 and two consecutive yarns of the intermediate layer 402-2, and also extending between the intermediate layer 402-2 and the machine-side layer 402-3 for four consecutive yarns of each of the intermediate layer 402-2 and the machine-side layer 402-3. The CD yarns 1806 separate the layers 402-1, 402-2, 402-3 with an upward binding force to improve the openness / permeability of the press fabric 1800 (e.g., at the machine side) and promote water transfer.

[0158] In some implementations, a press fabric includes straight yarns configured as separation yarns. For example, a CD yarn serving a separation function can extend straight between two specific MD layers of the press fabric, e.g., without crossing between MD layers.

[0159] For example, FIG. 27 illustrates an example of a two-layer press fabric 2700 having a straight separation yarn 2708. The press fabric 2700 can be understood as a variation of the press fabric 100. The separation yarn 2708 extends continuously between the paper-side layer 102-1 and the machine-side layer 102-2. It will be understood that the press fabric 2700 can have a system of separation yarns 2708 spaced apart from one another in the machine direction. The press fabric 2700 also includes a system of CD binder yarns 104 that bind the paper-side layer 102-1 and the machine-side layer 102-2, and a system of CD separation yarns 2706 that weave alternately over and under yarns of the paper-side layer 102-1, remaining on the paper side of the machine-side layer 102-2.

[0160] FIG. 28 illustrates an example of a three-layer press fabric 2800 having a straight separation yarn 2808. The press fabric 2800 can be understood as a variation of the press fabric 500. The separation yarn 2808 extends continuously between the intermediate layer 402-2 and the machine-side layer 402-3, performing a separation function that enhances the water extraction capabilities of the press fabric 2800. It will be understood that the press fabric 2800 can have a system of separation yarns 2808 spaced apart from one another in the machine direction. The press fabric 2800 also includes a system of CD binder yarns 504 that bind the paper-side layer 402-1 and the machine-side layer 402-3, and a system of CD separation yarns 506 that form a single-layer sequence as described with respect to the press fabric 500.

[0161] Although the separation yarn 2808 is shown as a straight yarn extending between the intermediate layer 402-2 and the machine-side layer 402-3, straight separation yarns within the scope of this disclosure are not limited to that configuration, and straight separation yarns may additionally or alternatively be included between a paper-side layer and an intermediate layer, and / or between intermediate layers.

[0162] As will be understood from the foregoing description, various combinations of numbers of binder systems and separation systems are within the scope of this disclosure. For example, the press fabrics 100, 200, 300, 400, 700, 1400, 1500, 1700, and 1800 each include one binder system and one separation system; the press fabrics 500 and 600 each include one binder system and two separation systems; the press fabrics 800, 1600 include one binder system and three separation systems; the press fabric 900 includes two binder systems and one separation system; and the press fabrics 1000, 1100, 1200, 1300 include two binder systems and three separation systems. Other combinations of these numbers are also within the scope of this disclosure.

[0163] In some implementations, a press fabric includes MD yarns in the paper-side layer (in this paragraph, referred to as “first yarns”) that are aligned with MD intermediate-layer yarns and MD yarns in the machine-side layer, and MD yarns in the paper-side layer (in this paragraph, referred to as “second yarns”) that are not aligned with, or are offset laterally from, the MD intermediate-layer yarns and MD machine-side yarns. This configuration is illustrated in all of the press fabrics of FIGS. 4A to 18. For example, the first yarns and the second yarns can alternate along the cross-machine direction, though the scope of this disclosure is not limited thereto, as shown, for example, in FIG. 10. In some implementations, it can be advantageous for separation yarns to bind on (e.g., form knuckles with) the second yarns, and for binder yarns to bind on (e.g., form knuckles with) the first yarns. For example, these separation yarns can form knuckles on top sides of (above) the second yarns, thereby separating with a force toward the paper side. This configuration is shown, for example, for press fabrics 400, 500, 600, 700, 800, 900, 1500, 1600, 1700, and 1800. In some implementations, having at least some of the separation yarns bind on the offset second yarns can be particularly advantageous, because, this configuration can provide a more symmetrical paper-side surface of the press fabric, improving smoothness of the paper side. This configuration may also facilitate easier or more efficient weaving of the press fabric, e.g., may provide weaving compatibility with a wider range of weaving machines. However, the scope of this disclosure is not limited to the foregoing configuration. For example, press fabrics 1000, 1100, 1200, 1300, and 1400 include separation yarns that bind on (form knuckles on) the first yarns, a configuration that can also advantageously provide an upward binding force that improves dewatering by the press fabric. Moreover, press fabrics 1000, 1100, 1200, and 1300 further include separation yarns that bind on yarns of the machine-side layer, thereby providing a downward binding force, to illustrate that the scope of this disclosure is not limited to separation yarns having an upward binding force.

[0164] In some implementations, a multi-layer press fabric includes specially-configured yarns in its seam area. For example, a multi-layer press fabric can include a combination of (i) one or more first additional yarns woven into the top layer of multiple layers and (ii) one or more second additional yarns woven into the seam loop. Together, these additional yarns can provide a synergistic effect that results in a reinforced seam area that exhibits improved lifetime. Further, the improved flap integrity provided by these additional yarns can result in less paper marking, due to better press and flow distribution. In some implementations, the yarns are texturized yarns. One or both types of additional yarns can be incorporated into any of the examples of press fabrics described herein.

[0165] FIG. 19 illustrates an example of a seam area of a three-layer press fabric 1900. For example, the press fabric 1900 can be any of the three-layer press fabrics described herein, such as press fabrics 400, 500, 600, 700, 900, 1400, 1500, 1600, 1700, 1800, or 2800. It will be understood, however, that the seam area configuration described with respect to FIG. 19 is also applicable to press fabrics with other numbers of layers, such as four-layer press fabrics, e.g., press fabrics 800, 1000, 1100, 1200, and 1300.

[0166] The press fabric 1900 includes two layers of MD yarns 1904 forming seam loops 1903 that can be joined together by a pintle or other joining element 1902, to form a seam 1901. A top layer of MD yarns 1910 is arranged above the seam 1901. The press fabric 1900 can be on-machine seamable. To provide the press fabric 1900 on the rolls (e.g., press rolls) of a papermaking machine, a flap can be cut through the top layer of MD yarns 1910 and an overlying staple fiber batt layer, to provide access to the seam 1901. However, absent the addition of yarns as described herein, the press fabric may lack CD yarns above the seam 1901, resulting in poor web anchorage on the top layer of MD yarns 1910, e.g., poor anchorage between the batt layer and the woven layers. Moreover, the removal of batt associated with the on-machine seaming process may change the air and water permeability of the seam area compared to the rest of the press fabric 1900. This difference in water permeability, or flow resistance, may cause sheet marking.

[0167] To improve performance of the press fabric 1900, first additional CD yarns 1906 are woven in the top layer (e.g., paper-side layer) of MD yarns 1910, in the seam area over the seam loops 1903. For example, the first additional CD yarns 1906 can be woven in only the top layer. For example, the first additional CD yarns 1906 can be woven with a plain-weave configuration, alternately weaving over and under the top layer of MD yarns 1910. The first additional CD yarns 1906 provides extra yarns for web anchorage, improving the mechanical properties of the press fabric 1900. In some implementations, a first first additional CD yarn 1906 is arranged on one side of the joining element 1902 in the machine direction, and a second first additional CD yarn 1906 is arranged on the other side of the joining element 1902 in the machine direction. The first additional CD yarns 1906 can be woven into a flap area that extends over the seam 1901. For example, the flap area can be an area that becomes a flap when cuts are made to permit on-machine seaming.

[0168] The press fabric 1900 further includes second additional CD yarns 1908 that are woven into the loops 1903 of the seam 1901. The second additional CD yarns 1908 can strengthen web anchorage down to the loops 1903. For example, the second additional CD yarns 1908 can be woven into the top layer of the loops 1903, adjacent to the top layer of MD yarns 1910. For example, the second additional CD yarns 1908 can be woven with a plain-weave configuration, alternately weaving over and under the top layer of the loops 1903. In some implementations, a first second additional CD yarn 1908 is arranged on one side of the joining element 1902 in the machine direction, and a second second additional CD yarn 1908 is arranged on the other side of the joining element 1902 in the machine direction. The second additional CD yarns 1908 can be woven under a flap that extends over the seam 1901.

[0169] In some implementations, the first additional CD yarns 1906 and / or the second additional CD yarns 1908 are textured yarns. For example, the first additional CD yarns 1906 and / or the second additional CD yarns 1908 can be multifilament yarns formed by tens of (e.g., at least 50) micro-yarns.

[0170] The first additional CD yarns 1906 and / or the second additional CD yarns 1908 can be the closest CD yarns to the seam 1901, among CD yarns of the press fabric 1900. For example, other CD yarns may be spaced laterally apart from the seam 1901, whereas the first additional CD yarns 1906 and / or the second additional CD yarns 1908 can vertically overlap the seam 1901 and / or the joining element 1902 or can be very close laterally to the seam 1901 and / or the joining element 1902. The other CD yarns can be, for example, separation yarns and / or binder yarns. For example, the other CD yarns can be yarns of a different type than the texturized yarns, such as non-texturized yarns.

[0171] The first additional CD yarns 1906 and / or the second additional CD yarns 1908, and especially the CD yarns 1906 and 1908 in combination with one another, can provide reinforced seams that exhibit high performance throughout the press fabric lifetime. For example, the first additional CD yarns 1906 and / or the second additional CD yarns 1908 can improve web flap integrity to reduce marking, as a result of better press and flow distribution. Fiber anchorage can be improved on the flap and non-flap sides. Web loss in the cut top layers over the seam 1901 can be reduced, avoiding seam-marks and paper cuts.

[0172] FIG. 20 illustrates another example of a press fabric 2000 including additional CD yarns in the seam area. The press fabric 2000 is similar to the press fabric 1900 of FIG. 19, and the elements of FIG. 20 can have characteristics as described for the corresponding elements of FIG. 19, except where noted otherwise or suggested otherwise by context.

[0173] The press fabric 2000 includes two layers of MD yarns 2004 forming seam loops 2003 that can be joined together by a joining element 2002, to form a seam 2001. A top layer of MD yarns 2010 is arranged above the seam 2001. First additional CD yarns 2006 (in this example, four first additional CD yarns 2006) are woven in the top layer of MD yarns 2010. Second additional CD yarns 2008 that are woven into the loops 2003 of the seam 2001.

[0174] Compared to FIG. 19, FIG. 20 further illustrates other CD yarns 2012, which are omitted from FIG. 19 for clarity of illustration and description. In some implementations, the CD yarns 2012 can include one or more systems of binder yarn and one or more systems of separation yarns, having weave configurations as described with respect to FIGS. 1 to 18. Thus, the advantageous weave configurations described with respect to FIGS. 1 to 18 can be realized in conjunction with improved seam areas as described with respect to FIGS. 19 and 20.

[0175] To provide one example, the intermediate layer 402-2 and the machine-side layer 402-3 of the three-layer press fabric 400 (illustrated in FIGS. 4A-4C) can form seam loops having second additional CD yarns woven therein, and / or the paper-side layer 402-1 can be the “top layer” (discussed with respect to FIGS. 19 and 20) having first additional CD yarns woven therein. As another example, at least two of the layers 802-2, 802-3, 802-4 of the four-layer press fabric 800 (described with respect to FIGS. 8A-8F) can form seam loops having second additional CD yarns woven therein, and / or the paper-side layer 802-1 can be the “top layer” having first additional CD yarns woven therein. In some implementations, the first additional CD yarns can be woven into multiple top layers. For example, the two lower layers 802-3, 802-4 can form seam loops, and the first additional CD yarns can be woven into the paper-side layer 802-1 or both the paper-side layer 802-1 and the upper intermediate layer 802-2. It will be understood that this description can equally be extended to the other three-layer and four-layer press fabrics described herein. Further, the second additional CD yarns, which are woven into seam loops, can be included in two-layer press fabrics, such as press fabrics 100, 200, and 300.

[0176] FIGS. 21 and 22 are cross-sectional and top views, respectively, of a seam area having first additional yarns 2106. The first additional yarns 2106 extend over seam loops 2103 and are woven into the top layer of MD yarns 2110. As shown in FIGS. 21 and 22, the additional yarns can have a different composition, type, and / or diameter from other yarns of the press fabric. For example, FIGS. 21 and 22 illustrate the textured, multifilament composition of some implementations of the first additional yarns 2106, which have a larger diameter than other yarns of the press fabric.

[0177] In the foregoing description, for conciseness, binding and force characteristics illustrated in the drawings, and disclosed for some press fabrics in the description, are sometimes omitted from the description for other press fabrics. However, it will be understood that, when a yarn configuration, and / or a benefit thereof, is described in reference to an illustrated example, the same yarn configuration, and / or the benefit thereof, applies equally to matching illustrated examples. In any of the press fabrics described herein, a CD separation yarn that forms a knuckle on a top side (paper side) of an MD yarn, exerts an upward binding force. When a CD yarn is described as extending adjacent to “consecutive” yarns of an MD layer, it will be understood that the CD yarn extends adjacent to the consecutive yarns of the MD layer while extending continuously adjacent to the MD layer and between the MD layer and an adjacent MD layer, e.g., without crossing between any MD layers.

[0178] The press fabrics described herein can be manufactured using any suitable weaving method. For example, in some implementations, the press fabrics are manufactured in an endless weaving machine. In some implementations, the press fabrics are woven by the endless weaving machine with the paper-side layer on the inside and the machine-side layer on the outside. The woven fabric can then be turned inside-out (such that the paper-side layer faces out) and mounted on rolls for use in pressing. In some implementations, the press fabrics are manufactured using a flat weaving machine. In that case, in some implementations, the woven fabric is joined / sewn to itself after weaving to form a loop suitable for mounting on rolls for use in pressing.

[0179] In some implementations, the press fabrics described herein can be manufactured using a relatively small number of harnesses, e.g., for improved manufacturing flexibility compared to press fabrics that require a higher number of harnesses. For example, in some implementations, press fabrics 100, 200, and 700 can be manufactured using twelve-harness weaving machines, and press fabrics 300, 400, 500, and 600 can be manufactured using sixteen-harness weaving machines. In some implementations, press fabric 800 can be manufactured using a 24-harness weaving machine. This relative ease of manufacturing can be associated with the CD yarn counts included in the press fabrics described herein. For example, the CD yarn systems of the press fabrics 100, 200, and 700 include six CD yarns, and the CD yarn systems of the press fabrics 300, 400, 500, and 600 include eight CD yarns. These relatively low CD yarn counts can be based on the weave patterns of the separation yarns described herein and contrast with some alternative weaves that incorporate higher CD yarn counts, e.g., twelve CD yarns in a three-layer weave.

[0180] The press fabrics described herein can include one or more batt layers. For example, a batt layer can be provided on the paper side and / or the machine side of any of the press fabrics described herein. The batt can be needled through layers of the press fabric to join the layers to one another. For example, needling can join the batt, a top layer of the press fabric, and lower layers of the press fabric that form a seam loop. For example, one or more batt layers can be attached to any layers of the press fabrics described herein, e.g., attached to the paper-side layer and / or the machine-side layer.

[0181] Accordingly, press fabrics for paper manufacture can be configured for improved water removal. Based on yarn densities of MD layers and / or weave patterns of CD yarn systems, void volume, permeability, and openness can be increased, and drainage and dewatering can be improved. Further, in some implementations, these advantages can be achieved without compromising the strength of the fabric and its ability to support paper.

[0182] While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of any invention or of what may be claimed, but rather as descriptions of features that may be specific to particular implementations of particular inventions. Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Examples

Embodiment Construction

[0077]Various aspects of this disclosure describe fabrics and weave patterns for use in papermaking, e.g., as press fabrics. In some implementations, the disclosed fabrics can exhibit high void volume, openness, and binding characteristics that improve water removal from paper sheets and water transfer out of the fabrics themselves.

[0078]During the press section of a papermaking process, the efficacy of water removal from the paper sheet depends in large part on the characteristics of the press fabric. For example, fabrics with higher void volume (the open volume within the fabric that is not occupied by yarns / fibers) may be able to remove more water, as the voids provide space for water storage, thereby improving dewatering / water removal for the paper sheet. Layers of the press fabric with higher permeability / openness can also promote water removal. For example, when layers further from the paper sheet (e.g., a layer opposite the paper sheet) have higher permeability / openness, wate...

Claims

1. A press fabric for paper manufacture, the press fabric comprising:three or more layers of machine direction (MD) yarns, wherein the three or more layers comprise:a paper-side layer at a paper side of the press fabric,a machine-side layer at a machine side of the press fabric, andone or more intermediate layers between the paper-side layer and the machine-side layer,wherein the paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer;a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers; anda second system of CD yarns, wherein the CD yarns of the second system pass outside the paper-side layer and remain inside the machine-side layer.

2. The press fabric of claim 1, wherein the paper-side layer comprises:first yarns that are aligned with corresponding yarns of the machine-side layer and the one or more intermediate layers; andsecond yarns that are offset from yarns of the machine-side layer and the one or more intermediate layers,wherein the first yarns alternate with the second yarns along the cross-machine direction, andwherein the CD yarns of the second system form knuckles on the paper side of the second yarns.

3. The press fabric of claim 1, wherein the one or more intermediate layers and the machine-side layer include a same number of yarns per unit length along the cross-machine direction.

4. The press fabric of claim 3, wherein the paper-side layer has a 2:1 ratio of yarns per unit length along the cross machine direction with the one or more intermediate layers and with the machine-side layer.

5. The press fabric of claim 1, wherein the CD yarns of the second system comprise separation yarns with a binding force toward the paper side.

6. The press fabric of claim 1, wherein the CD yarns of the second system form a single-layer sequence.

7. The press fabric of claim 1, wherein the CD yarns of the second system, while extending continuously adjacent to a layer of the one or more intermediate layers, extend adjacent to multiple consecutive yarns of the layer.

8. The press fabric of claim 7, wherein the layer is a layer that is closest to the paper-side layer among the one or more intermediate layers.

9. The press fabric of claim 1, wherein the CD yarns of the second system form knuckles on the paper side of yarns of the paper-side layer.

10. The press fabric of claim 1, comprising a third system of CD yarns,wherein the CD yarns of the third system extend between the machine-side layer and the one or more intermediate layers and remain inside the machine-side layer.

11. The press fabric of claim 10, wherein the CD yarns of the third system bind, toward the paper side, a layer that is closest to the machine-side layer among the one or more intermediate layers.

12. The press fabric of claim 10, wherein the CD yarns of the third system remain inside the paper-side layer.

13. The press fabric of claim 10, wherein the CD yarns of the third system form a single-layer or double-layer sequence.

14. The press fabric of claim 1, wherein a permeability of the machine-side layer is higher than a permeability of the paper-side layer.

15. The press fabric of claim 1, wherein the one or more intermediate layers comprise a plurality of intermediate layers, andwherein the press fabric comprises a third system of CD yarns, wherein the CD yarns of the third system extend between two intermediate layers of the plurality of intermediate layers, andwherein the CD yarns of the third system remain inside the paper-side layer and the machine-side layer.

16. The press fabric of claim 1, wherein the one or more intermediate layers comprises a plurality of intermediate layers,wherein the CD yarns of the second system comprise separation yarns with a binding force toward the paper side, andwherein the press fabric comprises a third system of CD yarns, wherein the CD yarns of the third system comprise separation yarns with a binding force toward the machine side.

17. The press fabric of claim 1, wherein the CD yarns of the first system bind the paper-side layer together with the first intermediate layer of the one or more intermediate layers, andwherein the press fabric comprises a third system of CD yarns, wherein the CD yarns of the third system bind the machine-side layer together with the first intermediate layer or a second intermediate layer of the one or more intermediate layers.

18. The press fabric of claim 1, comprising a third system of CD yarns,wherein the CD yarns of the third system pass outside the machine-side layer and remain inside the paper-side layer.

19. The press fabric of claim 1, wherein the one or more intermediate layers comprise a plurality of intermediate layers, andwherein the CD yarns of the first system remain toward the paper side of a layer that is closest to the machine-side layer among the plurality of intermediate layers.

20. The press fabric of claim 1, wherein the one or more intermediate layers comprise a plurality of intermediate layers,wherein the first intermediate layer has a same number of yarns per unit length along the cross-machine direction as the paper-side layer,wherein a second intermediate layer of the plurality of intermediate layers has a same number of yarns per unit length along the cross-machine direction as the machine-side layer, andwherein the second intermediate layer is closer to the machine-side layer than is the first intermediate layer.

21. The press fabric of claim 1, wherein MD yarns of two layers of the machine-side layer and the one or more intermediate layers form seam loops, andwherein the press fabric comprises:first CD yarns woven in the paper-side layer and arranged over the seam loops, andsecond CD yarns woven in the seam loops,wherein the first CD yarns and the second CD yarns comprise texturized yarns.

22. The press fabric of claim 21, wherein the first CD yarns and the second CD yarns are closer to the seam loops than are the first system of CD yarns and the second system of CD yarns.

23. The press fabric of claim 1, comprising a third system of CD yarns, wherein the CD yarns of the third system are straight yarns that extend between the paper-side layer and the one or more intermediate layers, between two intermediate layers of the one or more intermediate layers, or between the one or more intermediate layers and the paper-side layer.

24. The press fabric of claim 1, comprising one or more layers of batt attached to at least one of the paper-side layer or the machine-side layer.

25. A press fabric for paper manufacture, the press fabric comprising:three or more layers of machine direction (MD) yarns, wherein the three or more layers comprise:a paper-side layer at a paper side of the press fabric,a machine-side layer at a machine side of the press fabric, andone or more intermediate layers between the paper-side layer and the machine-side layer,wherein the paper-side layer includes more yarns per unit length along a cross-machine direction than the machine-side layer;a first system of cross-machine direction (CD) yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers; anda second system of CD yarns, wherein the CD yarns of the second system separate the paper-side layer from the one or more intermediate layers.

26. The press fabric of claim 25, comprising a third system of CD yarns, wherein the CD yarns of the third system separate the machine-side layer from the one or more intermediate layers.

27. The press fabric of claim 25, wherein the CD yarns of the second system have a binding force toward the paper side.

28. A press fabric for paper manufacture, the press fabric comprising:three or more layers of machine direction (MD) yarns, wherein the three or more layers comprise:a paper-side layer at a paper side of the press fabric,a machine-side layer at a machine side of the press fabric, andone or more intermediate layers between the paper-side layer and the machine-side layer,wherein MD yarns of two layers of the machine-side layer and the one or more intermediate layers form seam loops; andcross-machine direction (CD) yarns, wherein the CD yarns comprise:first CD yarns woven in the paper-side layer and arranged over the seam loops, andsecond CD yarns woven in the seam loops.

29. The press fabric of claim 28, wherein the first CD yarns and the second CD yarns comprise texturized yarns.

30. The press fabric of claim 29, comprising:a first system of CD yarns, wherein the CD yarns of the first system bind the paper-side layer together with the machine-side layer or a first intermediate layer of the one or more intermediate layers,wherein the CD yarns of the first system have a different composition from the first CD yarns and the second CD yarns, andwherein the first CD yarns and the second CD yarns are closer to the seam loops than are the first system of CD yarns.

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