Abstract: A forming section for a twin fabric papermaking machine, wherein after stock impingement, the two fabrics carry and sandwich the stock. A plurality of spaced apart drainage shoes, selectively provided to either or both of the fabrics, provides continuous support in the machine direction for the respective fabric in sliding contact, and each drainage shoe deflects the fabrics by a selected angle of wrap comprising an angular displacement between the leading edge and the trailing edge of the drainage shoe. At least one of the drainage shoes is secured to a drainage box and is provided with a plurality of drainage openings extending from the fabric contacting surface through to the machine side surface of the shoe. The arrangements of the invention provide improved drainage and formation of the paper web.

Abstract: A method of manufacturing a cellulosic sheet having at least one of hydrophobic and oleophobic properties comprises the steps of depositing a stock of cellulosic fibers onto at least one forming fabric at an impingement zone and forming a web therefrom in a formation process; combining a water-based composition comprising an adhesion promoter, an organic nanoparticulate polymer and a fluorocarbon with the web at a preselected combination stage prior to a heating stage at which the web is subjected to a temperature exceeding 60° C.; and heat-curing the composition with the web during a drying process. A water-based composition for imparting at least one of hydrophobic and oleophobic properties to a cellulosic sheet during manufacture comprises an adhesion promoter, an organic nanoparticulate polymer and a fluorocarbon. A cellulosic sheet or layer thereof has at least one of hydrophobic and oleophobic properties. Improved resistance of cellulosic sheets to oil or water is obtained.

Abstract: A papermaker's fabric including at least one system of warp yarns interwoven with at least first and second systems of weft yarns, with the weft yarns of the first system of weft yarns having a vertical dimension that is greater than a vertical dimension of the weft yarns of the second system. The fabric has a papermaking surface and a machine side surface, and in the papermaking surface, the yarns of the first system of weft yarns are interwoven with the warp yarns to provide groups of four weft yarn floats which form four corners of a box shape, the yarns of the second system of weft yarns are interwoven with the warp yarns so as to pass through the bottom of the box shape, and further provide support areas in pockets located adjacent to the box shapes, and at least one yarn from the second system of weft yarns interweaves with the warp yarns to occupy space in a center plane of the fabric so as to restrict or retard drainage and thereby increase a center plane resistance of the fabric.

Abstract: A woven filtration fabric for cellulosic sheet formation. The warp yarns comprise intrinsic binder yarn pairs, and a set of dedicated machine side layer warp yarns. The members of each intrinsic binder yarn pair alternate with each other to define a single combined path in each layer. Whenever a member interweaves with a machine side layer weft yarn, at least one machine side layer warp yarn interweaves with the same weft yarn in the same knuckle. In some embodiments, the members form double knuckles in the machine side layer, firstly together with a first machine side layer warp yarn and then together with a second machine side layer warp yarn. The warp yarn path ratio of machine side layer warp yarns to single combined paths of the intrinsic binder yarn pairs is at least 1.5:1. The fabrics provide increased center plane resistance, resulting in improved drainage and sheet uniformity.

Abstract: Papermaker's forming fabrics including extruded thermoplastic monofilaments formed from a polymer blend consisting of from about 51%-90% pbw (parts by weight) of a poly(ethylene naphthalate) (PEN) polymer having a melt point of from 249° C. to about 278° C., most preferably between about 262° C. and 273° C., and an intrinsic viscosity of from 0.45 to about 0.95, preferably from about 0.65 to about 0.85, along with from about 49%-10% pbw of a poly(ethylene terephthalate) (PET) polymer having an intrinsic viscosity of between about 0.55 to about 1.05, preferably from about 0.85 to 1.0. Monofilaments formed from the novel polymer blend exhibit physical properties differing from those obtained from monofilaments formed of 100% PEN polymer, making them particularly suitable for use in weaving and processing the forming fabrics of the present invention.

Abstract: Dewatering blades for use in papermaking machines are assembled from two or more pre-finished sub-assemblies which are in turn mounted on a base member. Each sub-assembly comprises a holder, configured to receive a plurality of segments, constructed of a wear-resistant material such as ceramic, which will be located so as to be in sliding contact with the underside of a papermaking fabric. The holders are adapted for insertion into and retention in the base member, which is subsequently affixed to the papermaking machine by known means. The construction of the sub-assemblies allows for the manufacture of a full length blade from a plurality of sub-assemblies, which dramatically reduces manufacturing cost while providing for more rapid deliveries and simplified repair of damaged blades.

Abstract: A flat woven industrial filtration fabric comprises three layers of weft yarns. A first set of warp yarns interweaves only with paper side layer weft yarns and intermediate weft yarns, and a second set of warp yarns interweaves only with machine side layer weft yarns and the intermediate yarns, the first warp yarns and the second warp yarns interweaving with the same intermediate weft yarns at common turning points. The first warp yarns comprise groups of intrinsic binder yarns forming a single combined path on the paper side surface, and the second warp yarns are woven as individual yarns or in groups, such as pairs or triplets. The distinct nature of the paper side and machine side layers increases the available combinations of weave patterns to optimize the characteristics for each layer, and the distinct centre planes between the three layers provide improved drainage control.

Abstract: Papermaker's forming fabrics including extruded thermoplastic monofilaments formed from a polymer blend consisting of from about 51%-90% pbw (parts by weight) of a poly(ethylene naphthalate) (PEN) polymer having a melt point of from 249° C. to about 278° C., most preferably between about 262° C. and 273° C., and an intrinsic viscosity of from 0.45 to about 0.95, preferably from about 0.65 to about 0.85, along with from about 49%-10% pbw of a poly(ethylene terephthalate) (PET) polymer having an intrinsic viscosity of between about 0.55 to about 1.05, preferably from about 0.85 to 1.0. Monofilaments formed from the novel polymer blend exhibit physical properties differing from those obtained from monofilaments formed of 100% PEN polymer, making them particularly suitable for use in weaving and processing the forming fabrics of the present invention.

Abstract: A papermaking fabric is treated by applying a nanoparticle type coating to improve their resistance to contamination by foreign matter in the papermaking system. The coating is applied during fabric manufacture and cured during heat setting. Alternatively, the coating applied or renewed by utilizing an existing shower or locating a spray boom or other suitable coating application device in the dryer section to apply the coating to the fabric in a controlled, uniform manner. Prior to application of the coating, the fabric is first thoroughly cleaned such as by showering or spraying, and then dried. Following controlled application of the coating, any excess material is removed by a suitable means, such as by vacuum, and the remaining coating on the fabric is then cured, either by utilizing the ambient heat of the dryer section or by a portable bank of heaters. In this manner, the fabric does not have to be removed from the machine in order to apply or renew the contaminant resistant coating.

Abstract: A fabric for use in the production of nonwoven material webs comprises at least one component system of monofilament polymeric yarns in each of the machine and cross-machine directions. At least some of the yarns of at least one system comprise surface roughened yarns having a substantially flat surface exposed in the web-contacting surface, with a surface roughness between 5 ?m and 100 ?m. The fabric can be woven, optionally including conductive yarns in either or both of the machine or cross-machine directions. The fabric can also be a spiral link construction comprising coils of helically assembled yarns, at least some of which will be surface roughened yarns; surface roughened stuffer yarns can also be provided within the coils. The fabrics have increased resistance to contamination by materials deposited during web formation and improved web release.

Abstract: A papermaking fabric is treated by applying a nanoparticle type coating to improve their resistance to contamination by foreign matter in the papermaking system. The coating is applied during fabric manufacture and cured during heat setting. Alternatively, the coating applied or renewed by utilizing an existing shower or locating a spray boom or other suitable coating application device in the dryer section to apply the coating to the fabric in a controlled, uniform manner. Prior to application of the coating, the fabric is first thoroughly cleaned such as by showering or spraying, and then dried. Following controlled application of the coating, any excess material is removed by a suitable means, such as by vacuum, and the remaining coating on the fabric is then cured, either by utilizing the ambient heat of the dryer section or by a portable bank of heaters. In this manner, the fabric does not have to be removed from the machine in order to apply or renew the contaminant resistant coating.

Abstract: Segments, typically ceramic, for use in dewatering blades for papermaking and similar machines comprise lower surfaces to each of which at least one interlock member is bonded. The segments are installed by inserting the interlock members into a channel in an intermediate sub-assembly or base member. The members are securely attached within the channel by a suitable adhesive, or clip means to engage the interlock members, with the optional addition of an adhesive. The segments and dewatering blades, and a method of manufacture, allows for the segments to be made as flat units, without unnecessary angular surfaces, simplifies their attachment to the base, and reduces the occurrence of stress cracking or other damage to the segments. A single segment can be used in various dewatering blade types and in more than one orientation in dewatering blades, reducing manufacturing costs by unitizing construction.

Abstract: A forming section for a gap blade former type papermaking machine having a headbox which delivers a jet of papermaking stock between a conveying forming fabric and a backing forming fabric is provided. The conveying fabric moves in sliding contact over an impingement shoe on which the jet of papermaking stock is delivered at a point of impingement. A forming shoe located immediately downstream of the impingement shoe over which the backing forming fabric slides. The impingement shoe is mounted for at least one of pivoting and transverse movement so that a position of the point of impingement of the jet of papermaking stock can be adjusted by at least one of rotating the impingement shoe about a first pivot point and transversely shifting the impingement shoe. The forming shoe can also be mounted for movement.

Abstract: A triple layer woven industrial fabric, particularly suitable for through-air drying applications, has a paper side (PS) layer and a machine side (MS) layer of polymeric warp and weft yarns woven to a repeat pattern wherein all the warp yarns are arranged as vertically stacked pairs, all the weft yarns comprise pairs of intrinsic weft binder yarns, and each pair of weft yarns forms an unbroken weft path in both the PS layer and the MS layer whereby when either the first or second member of the pair passes from the PS layer to the MS layer, the other member of the pair passes from the MS layer to the PS layer at an exchange point located between at least one common pair of warp yarns.

Abstract: A double layer forming fabric for a papermaking machine is warp-tied, all the warp yarns comprising binder pairs which forming a single combined path in the paper side surface. The pair members exchange positions at an exchange point between successive path segments and are laterally displaced in relation to each other at and between each exchange point. For each successive pair, an order of insertion of the first and second members in relation to each other into the weave is inverted in relation to the order of insertion for members of the immediately preceding pair, such that each first member is adjacent to the first member of the adjacent pair at the closest exchange point, and each second member is adjacent to the second member of the adjacent pair at the closest exchange point. The fabric has improved drainage uniformity leading to improved paper formation and reduced sheet marking.

Abstract: A headbox including a stock dilution profiling arrangement and associated stock delivery systems are provided, which together deliver to the forming section of a papermaking machine a uniform stock flow with more consistent basis weight and fiber orientation profiles than has previously been possible. These improvements in basis weight uniformity and fiber orientation profile provide benefits in paper sheet formation and related paper properties.

Abstract: A cover for a vacuum dewatering box that is formed from a plurality of blocks, each including a wear surface, is provided. At least some of the blocks are spaced apart to form at least one generally longitudinally oriented slot through the cover, with a shape and size of the at least one slot being determined by at least one of a location of and a shape of the blocks. Preferably, the at least one slot is formed with a zig-zag or herringbone pattern, and can be used on a suction box or Uhle box on a papermaking machine. A vacuum dewatering box having this type of cover is also provided.

Abstract: A twin fabric hybrid forming section for paper making machine is described in which: the pitch of the fabric support elements decreases progressively in the machine direction; the level of vacuum applied to the forming fabrics through the dewatering boxes increases in the machine direction; the two forming fabrics together with the stock sandwiched between them traverse at least four separate and distinct vacuum zones within the forming section as they proceed in the machine direction; the level of vacuum applied to the last of the at least four separate and distinct vacuum zones is higher than the level of vacuum applied to the first of the separate and distinct vacuum zones; the level of vacuum applied to the at least four separate and distinct vacuum zones follows a preselected profile; and the dewatering boxes carrying the fabric support elements are arranged so that the fabric support elements are located in an alternating sequence on the machine sides of both of the forming fabrics.

Abstract: A twin fabric gap former forming section for paper making machine is described in which: the pitch of the fabric support elements d decreases progressively in the machine direction; the level of vacuum applied to the forming fabrics through the dewatering boxes increases in the machine direction; the two forming fabrics together with the stock sandwiched between them traverse at least four separate and distinct vacuum zones within the forming section as they proceed in the machine direction; the level of vacuum applied to the last of the at least four separate and distinct vacuum zones is higher than the level of vacuum applied to the first of the separate and distinct vacuum zones; the level of vacuum applied to the at least four separate and distinct vacuum zones follows a preselected profile; and the dewatering boxes carrying the fabric support elements are arranged so that the fabric support elements are located in an alternating sequence on the machine sides of both of the forming fabrics.

Abstract: A fabric support element for a papermaking machine has improved fluid drainage means, comprising openings which can include flow-through vents. The element can comprise an impingement shoe for a forming section of a papermaking machine. The opening can be defined by a plurality of laminar segments, at least some of which define a paper side surface of the element, and which segments can be spaced apart by additional laminar segments or other spacing means. Laminar segments for use in the element, a method of constructing the element, and a papermaking machine, or a forming section thereof, including the element are also provided.