Abstract: A device for producing a fibrous sheet, including a water squeezing section which squeezes the dispersion medium from a dispersion to generate a web, and a drying section which dries the web to generate a fibrous sheet, the water squeezing section having multiple first fabric sheets arranged longitudinally along the transport direction of a web substrate that is partway through web generation, and water squeezing units which are provided beneath the multiple first fabric sheets and squeeze the dispersion medium from the dispersion, and in the water squeezing section, a continuous sheet is positioned so as to extend over the upper surface of the multiple first fabric sheets, and the dispersion is discharged onto the upper surface of the continuous sheet.

Abstract: A device for producing a fibrous sheet, including a water squeezing section which squeezes the dispersion medium from a dispersion to generate a web, and a drying section which dries the web to generate a fibrous sheet, the water squeezing section having multiple first fabric sheets arranged longitudinally along the transport direction of a web substrate that is partway through web generation, and water squeezing units which are provided beneath the multiple first fabric sheets and squeeze the dispersion medium from the dispersion, and in the water squeezing section, a continuous sheet is positioned so as to extend over the upper surface of the multiple first fabric sheets, and the dispersion is discharged onto the upper surface of the continuous sheet.

Abstract: A device for producing a fibrous sheet, including a water squeezing section which squeezes the dispersion medium from a dispersion to generate a web, and a drying section which dries the web to generate a fibrous sheet, the water squeezing section having multiple first fabric sheets arranged longitudinally along the transport direction of a web substrate that is partway through web generation, and water squeezing units which are provided beneath the multiple first fabric sheets and squeeze the dispersion medium from the dispersion, and in the water squeezing section, a continuous sheet is positioned so as to extend over the upper surface of the multiple first fabric sheets, and the dispersion is discharged onto the upper surface of the continuous sheet.

Abstract: Method and apparatus for moulding an article from pulp material, in which the article is moulded on the surface of a mould tool, the article is pressed and the pressed article is dried, using heated gas or superheated steam that is passed through the pressed article or using microwaves, in which the pressed article is retained on a tool during the drying. The tool may be the mould tool or a different tool.

Abstract: A device for drying and treating a fiber-based moving fiber web (1) in a machine intended for producing tissue paper includes a metal belt (2) which is arranged to support the fiber web (1) and to transfer the fiber web (1) in the machine direction and which metal belt (2) is arranged as a continuous rotating cycle, at least one roll (3) the shell of which is in contact with the metal belt (2) arranged to rotate around, which roll (3) is for supporting and/or controlling the metal belt (2), and at least one counter element (5) arranged to create a contact area outside the metal belt (2) between the metal belt (2) and the counter element (5) for a process zone (6), via which process zone (6) the fiber web (1) is arranged to travel when using the device.

Abstract: A tissue papermaking machine is described, comprising a wet section and a press section comprising a single press with first and second press elements forming a press nip, and with a press felt running through the press nip in contact with the formed fiber web, whereby the second press element is arranged inside the loop of the press and felt, and a smooth belt runs through the press nip in contact with the formed fiber web, whereby the first press element is arranged inside the loop of the belt, and a transfer roll arranged inside the loop of the belt forming a transfer nip with a drying surface, whereby the smooth belt carries the fiber web between the press nip and the transfer nip. A pre-dewatering device is arranged upstream of the press to dewater the fiber web to a dry content of 15-30%. Associated methods are also provided.

Abstract: A clothing for supporting a wet paper web for dewatering is provided, comprising a dewatering fabric extending in a machine direction and formed only from a woven material to have a single, substantially consistent, permeability. A pair of laterally-spaced strip portions extend along the dewatering fabric in the machine direction, with each being substantially and consistently impermeable to air and forming a substantially and consistently smooth non-water-retaining surface. The strip portions define a permeable web-carrying portion of the dewatering fabric therebetween, wherein the paper web carried thereby extends over the entire width thereof. The permeable web-carrying portion allows air to flow therethrough, exclusively of the impermeable strip portions, such that the wet paper web carried only by the permeable web-carrying portion is dewatered. The width of the permeable web-carrying portion thereby defines the width of the wet paper web dried thereon. Associated systems and methods are also provided.

Abstract: A steam shower is provided for supplying steam to a web in a paper machine. The steam shower includes a diffuser assembly mounted to the cross-beam for movement in the direction of the longitudinal axis of the cross beam. The cross-beam defines an interior steam header for connection to a source of steam. The diffuser assembly includes a plurality of separated steam compartments. The diffuser assembly may be part of a steam provision assembly that is also mounted to the cross-beam for movement in the direction of the longitudinal axis of the cross beam. In addition to the diffuser assembly, the steam provision assembly includes a second steam header and steam valve modules.

Abstract: An apparatus for handling a moving material web includes: a treatment unit including a rotating conveyor belt which forms a closed loop and carries the material web; a second treatment unit with a second conveyor belt which also forms a closed loop, both treatment units being connected parallel relative to each other; a first switch-over for the transfer of the web from the first to the second conveyor belt; and a second switch-over unit for the transfer of the web from the second to the first conveyor belt.

Abstract: A papermaking machine for making uncreped through air dried paper having a forming section, a press section, and a drying section is disclosed. The paper web is pressed between two press members while enclosed between a press felt and a transfer belt having non-uniformly distributed microscopic depressions in its surface. The web follows the transfer belt from the press to a transfer point at which the web is transferred via a suction transfer device onto a structuring fabric. The web is then dried with a through air dryer.

Abstract: A shoe device secured to a syphon is disclosed for removing condensate from an internal surface of a rotating cylinder. The shoe device includes a shoe portion which is disposed adjacent to the internal surface of the rotating cylinder. The shoe portion defines a passageway having an upstream and a downstream end. The passageway permits a flow there through of the condensate from the internal surface of the rotating cylinder, through the upstream end of the passageway to the downstream end of the passageway. The shoe portion has a first and a second side, a surface extending between the first and second sides of the shoe portion. The surface is disposed adjacent to the internal surface of the cylinder. The shoe portion also has a leading and a trailing end and a face extending between the leading and trailing ends of the shoe portion. A clamp is secured to a distal end of the syphon and is connected to the shoe portion for clamping the shoe portion to the syphon.

Abstract: A drying wire provided with an independent top fabric and bottom fabric. The bottom fabric is woven from longitudinal and cross direction monofilament yarns. The top fabric is woven from longitudinal yarns and shapeable cross direction yarns. The shapeable yarns make the structure of the top fabric denser and increase the contact surface area and the number of contact points. On the other hand, the bottom fabric is also smooth, wherefore it has good aerodynamic properties.

Abstract: A disclosed heating apparatus for heating a substrate on which a film is coated includes a process chamber having a gas supply opening for supplying a first gas to the process chamber and a gas evacuation opening for evacuating the first gas from the process chamber; a heating plate that is arranged in the process chamber and includes a heating element for heating the substrate; plural protrusions arranged on the heating plate so as to support the substrate; plural suction holes formed in the heating plate so as to attract by suction the substrate toward the heating plate; and a gas inlet adapted to supply a second gas to a gap between the heating plate and the substrate supported by the plural protrusions.

Abstract: The object of the invention is an end part (1) of an air dryer, the air dryer being applicable for drying a pulp web, such as a cellulose web or the like. The end part comprises a fan tower (11), and a roll tower in which a number of turn roll (27, 37) are arranged mainly on top of each other in order to turn the travelling direction of the pulp web in the air dryer, the longitudinal axis of the roll. towers being parallel, and a fan tower arranged at a distance from the roll tower, adjacent to it, comprising a number of fans arranged on top of each other, a single fan being arranged to blow heated air as drying air to a dryer group. The end part further comprises one or more centrifugal fans (14) arranged in the direct vicinity or the roll tower, and a number of end drying means (13) arranged between the roll tower and the dryer group of—the fan of the fan tower, to which end drying means drying air is supplied with said centrifugal fan or fans.

Abstract: Paper machine for manufacturing a fiber web of paper without through air drying (TAD) or pressing, comprising: a wet end, having a wire section with at least one forming wire, a clothing, being air and water permeable, and a dewatering unit for dewatering the fiber web; and a drying section, comprising a drying surface for the fiber web; and also a transfer roll for transferring the fiber web to the drying section, wherein the fiber web is supported by said clothing from the wire section all the way to and over the transfer roll. The clothing has a three dimensional structure for structuring the fiber web.

Abstract: Apparatus and method for treating a material web, which has at least one nip through which the material web is guided and which is formed between a first revolving, heated surface and a second revolving surface, it being possible for the first surface to be heated to at least 120° C. and both surfaces in the nip having the same direction of movement as the material web. Good surface quality of the material web is obtained by providing a box which bounds a space through which the material web is guided, the space being arranged after the first or after the last nip in the direction of movement of the web.

Abstract: The method and equipment are for the evaporation of hot black liquor obtained from a digestion process during the production of cellulose pulp. The black liquor is led to a multistage evaporation line with at least five evaporation stages. The black liquor that is to undergo evaporation in the evaporation line is cooled in at least one heat exchange process in a heat exchanger (HE1) against the partially evaporated black liquor that has undergone evaporation in at least one stage (I). The black liquor that is to undergo evaporation is cooled and the partially evaporated black liquor is heated by at least 5-10° C. The risk for the formation of foam and the separation of methanol are reduced. The greater part of the evaporation takes place at low temperature and at the lowest level of dry matter content in the liquor, which also suppresses encrustation in the stage.

Abstract: The object of the invention is an end part (1) of an air dryer, the air dryer being applicable for drying a pulp web, such as a cellulose web or the like. The end part comprises a fan tower (11), and a roll tower in which a number of turn roll (27, 37) are arranged mainly on top of each other in order to turn the travelling direction of the pulp web in the air dryer, the longitudinal axis of the roll. towers being parallel, and a fan tower arranged at a distance from the roll tower, adjacent to it, comprising a number of fans arranged on top of each other, a single fan being arranged to blow heated air as drying air to a dryer group. The end part further comprises one or more centrifugal fans (14) arranged in the direct vicinity or the roll tower, and a number of end drying means (13) arranged between the roll tower and the dryer group of—the fan of the fan tower, to which end drying means drying air is supplied with said centrifugal fan or fans.

Abstract: There is described a method and apparatus for applying steam from a steam source to a moving web to thereby improve the smoothness and gloss of the web. A housing has at least one cooling chamber upstream and at least one steam chamber downstream. The cooling air in the cooling chamber is used to cool the web before steam is applied to the web from the steam chamber. This allows a sufficient volume of steam to be delivered to the web to thereby raise its moisture content to a desired level to thus achieve optimized calendering of the web.

Abstract: The temperature of the ceramic elements of a supporting or wiping strip that is assigned to a wire or a felt in a paper production facility, is controlled by guiding a cooling carrier medium or a heating carrier medium through the supporting or wiping strip. For that purpose, the supporting or wiping strip is formed with at least one channel, through which the carrier medium for heat or for cold is pumped.

Abstract: A method and an apparatus for heating a roller used in the production and/or finishing of a web of material, particularly a paper web or paperboard web, are provided. According to the method, a roller is heated from the outside by a heated gas. The apparatus is configured to heat a roller used in the production and/or finishing of a web of material according to the method.

Abstract: The invention features methods and systems for calcining wet calcium carbonate lime mud produced in a re-causticizing manufacturing operation, for instance, Kraft pulp mill lime mud (“lime mud”) and converting it to re-burned lime by (a) feeding wet lime mud obtained from a re-causticizing manufacturing process into a flash dryer and then feeding the dried lime mud into a bubbling fluid bed calciner thermally linked by moving media heat transfer (MMHT) utilizing solid particulate media to a circulating fluid bed combustor wherein the MMHT provides heat input for calcination and drying; (b) recycling the media being from said calciner to said combustor wherein said combustor receives mill WWTP sludge, or precipitated lignins, or biomass, or NCGs as fuels to re-heat the solid particulate media; and (c) recovering calcined “soft-burned” lime mud from the fluid bed calciner.

Abstract: The invention relates to a belt for a machine for the production of web material, especially paper or cardboard, including a carrying structure and a pattern of wear-resistant material on at least one side of the carrying structure. The invention further relates to a machine for the production of a fibrous web in which the inventive belt is utilized.

Abstract: An impregnation vessel including: a vessel container including an upper inlet to receive cellulosic material; a lower discharge port to discharge the cellulosic material from a discharge section of the vessel container; a convergence section internal to the vessel through which passes a flow of the cellulosic material in the vessel; a cavity between an internal wall of the vessel and the convergence section, wherein the cavity has a lower opening to the cellulosic material in the vessel and an upper section shielded from the flow of cellulosic material in the vessel, and an input port in the vessel and opening to the cavity, wherein the input port is connectable to a source of hot liquid to be added to the cellulosic material in the vessel.

Abstract: Dryer section for drying a fibrous web supported by at least one drying fabric. The dryer section includes a plurality of heated drying cylinders, a plurality of guide rolls, and a plurality of dampening devices arranged at different locations relative to the fibrous web. Each dampening device applies a quantity of liquid to the fibrous web. In at least in one of the plurality of dampening devices, the quantity of the liquid is adjustable separately in zones transversely with respect to a web running direction. This Abstract is not intended to define the invention disclosed in the specification, nor intended to limit the scope of the invention in any way.

Abstract: The invention includes a method and system for generating electricity using a drive for the electrical generator that is powered by an engine that uses high pressure hot gases produced by combustion of a fuel and an oxygen bearing gas, using at least a portion of the electricity generated to power manufacturing plant equipment and using the waste hot exhaust gases from the heat engine, such as a gas turbine, with or without a heat exchanger, in an oven in which the mat is carried through continuously on a belt, drum or with other conventional means to dry the wet fibrous mats. Optionally the fibrous mats can contain a binder and the hot waste gases can be optionally used to cure a binder.

Abstract: A method and an apparatus for heating a roller used in the production and/or finishing of a web of material, particularly a paper web or paperboard web, are provided. According to the method, a roller is heated from the outside by a heated gas. The apparatus is configured to heat a roller used in the production and/or finishing of a web of material according to the method.

Abstract: A method and assembly is disclosed for moistening a web of paper or paperboard, the assembly comprising a steam blow cavity open toward a moving web (1). The steam blow cavity houses spray nozzles (5, 6, 7) at least for injecting steam into the cavity so as to form a steam atmosphere therein. Additionally, the steam blow cavity houses spray nozzles (5, 6, 7) for spraying a mist of a heated liquid onto the web (1) within the thus formed steam atmosphere.

Abstract: An apparatus for dewatering a fiber web in a paper machine includes a heated drying surface, a permeable fabric carrying the fiber web, and a condensing region adjacent a portion of the permeable fabric on a side opposite the fiber web. The fiber web is interposed between and contacts each of the heated drying surface and the permeable fabric. The condensation region has: a) a temperature which is less than a temperature of the permeable fabric; and/or b) a pressure which is greater than an ambient pressure.

Abstract: The invention relates to a device for continuous drying of a pulp sheet 10, particularly a tissue web, with a drying drum 1 and an air circulating system. It is mainly characterised by the drying drum 1 having a shell 12 with a perforated cylinder 20 that is externally supported by radial bearing rings 21.

Abstract: The invention relates generally to an improvement to a rotary joint and stationary siphon system typically for use in the papermaking process. Disclosed is a siphon support that has a bearing that rotatably engages with a siphon and flow openings that allow for steam flow from the rotary joint to the interior of a heat exchange roll. Further disclosed is a support device with a flow section that receives steam from the rotary joint and transmits it on to the heat exchange roll, wherein the flow section raises the pressure differential across the rotary joint by less than about 2 p.s.i. The support device is also only attached to the rotary joint and siphon thereby reduces the cantilever effect of the stationary siphon. Further disclosed are systems for papermaking that include the siphon support and rotary joint; the siphon support and stationary siphon; and the support, rotary joint and siphon. Further disclosed is a method of assembly wherein the support device is attached to a rotary joint and siphon.

Abstract: A belt for a material web producing machine and a process of producing the belt. The belt includes a plurality of long-chain strength supports arranged to form interstices and a filler at least partially filling the interstices. The process includes forming a sheet from a plurality of long-chain strength supports with the sheet including a plurality of interstices disposed between the long-chain strength supports, and filling at least a portion of the interstices with a filler.

Abstract: A nonwoven papermaker's fabric, usable in the dryer section of a paper machine, has a spiral wound machine direction (MD) base layer of raw stock which is wound around a pair of parallel rolls or cylinders until the desired length and width is achieved. The spiral wound MD layer is overlaid with a cross-machine direction (CD) layer of similar or dissimilar raw stock and mated by any of a number of means. The spiral wound MD layer can also be mated to another MD layer spiraled in the opposite direction and in one embodiment further mated to a CD layer. The fabric is preferably produced so that its neutral line is oriented toward the paper side of the fabric so that the paper sheet will stretch less than when typical dryer fabrics are used to turn the paper sheet and fabric around the dryer cylinders.

Abstract: A paper sterilization system comprises a chamber having one wall with an input slot and another wall with an output slot. A conveyor system is comprised of two co-acting belts, and upper and a lower. The belts are in facing contact. A plurality of rollers is provided. The rollers are adapted to convey the belts in contact with each other and with paper through the chamber from the input slot to the output slot. Also provided is a heating element. The heating element is adapted to increase the temperature to between about 150 and 400 degrees Fahrenheit. A pressure assembly is provided. The pressure assembly is adapted to increase the pressure to between about 1 and 4 atmospheres. Drive members are provided. The drive members are adapted to drive the belt and paper at a speed sufficient to kill viral and fungal organisms on paper moving through the chamber.

Abstract: A method and an apparatus for web threading in a drying section of a paper machine or the like. A leader (24) and a so called run-down strip are formed by cutting in the web coming to the drying cylinder in the drying section. An underpressure box (18) is arranged at the opening gap between the drying cylinder (14) and the drying wire, on that side of the wire which is away from the web, whereby this box can direct against the web an underpressure which is controllable in the machine's cross direction. The underpressure box creates an underpressure region (34?) between the leader and the underpressure box, the region having an underpressure p1 at the detachment point, i.e. in the area where the wire is detached from said drying cylinder (14), which underpressure is sufficient to detach the leader from said drying cylinder.

Abstract: A papermaking belt for use in making paper. The papermaking belt may be used in conjunction with a single-wire draw or twin-wire draw of a papermaking machine. The papermaking belt includes a woven reinforcing element and a patterned framework. The framework defines either or both faces of the papermaking belt. The pattern of the framework is independent of the weave of the reinforcing element.

Abstract: A method of dewatering a fiber web in a paper machine, includes the steps of: dewatering the fiber web in a forming section to a solids content of greater than approximately 10%; displacement pressing the fiber web in an air press assembly to a solids content of greater than approximately 40%; and through air drying the fiber web in at least one air press assembly to a higher solids content.

Abstract: Machine for the manufacture of fiber material web with shoe pressing unit and drying or tissue cylinder arranged to form at least one press nip. Water absorbent carrier band and water-impermeable pressing band being guided through the at least one press nip, and fiber material web is adapted to pass through the at least one press nip with the water absorbent carrier band and the water-impermeable pressing band. The at least one press nip has a length in web travel direction of less than or equal to approximately 60 mm. Pressure profile results over press nip length having maximum pressing pressure greater than or equal to approximately 3.3 MPa. The instant abstract is neither intended to define the invention disclosed in this specification nor intended to limit the scope of the invention in any way.

Abstract: An apparatus for decreasing heat emission and enhancing a vacuum system in a papermaking machine is provided. Such an apparatus includes a drying device having an inlet for receiving heated air for removing moisture from a paper web and an outlet for exhausting the moisture-containing air from the drying device. A vacuum system is configured to produce a suction and receive the moisture-containing air. A web handling device is disposed upstream of the drying device and is configured to interact with the web before the web is directed to the drying device. The web handling device is further configured to receive a portion of the moisture-containing air from the drying device, wherein the portion of the moisture-containing air is directed through the web by the web handling device to facilitate dewatering of the web before the moisture-containing air is received by the vacuum system.

Abstract: An air impingement arrangement and method for compensating for the curling tendency of a paper or board web which is being treated. Air impingement is disposed in connection with a paper or board process or with its finishing process and extends across the width of the web (10) running in the vicinity thereof, forming a contact-free web treatment zone, in which process the web is dried in at least one dryer unit (3, 5, 7) that applies single-wire draw. In accordance with the invention, air impingement directed at the web (10) is produced by the air impingement arrangement (20) in the web treatment zone, said air impingement including, one following after the other, at least one hot blowing with air and at least one cold blowing with air. The invention also relates to a paper or board machine provided with this kind of air impingement arrangement.

Abstract: There is described a method and apparatus for applying steam from a steam source to a moving web to thereby improve the smoothness and gloss of the web. A housing has at least one cooling chamber upstream and at least one steam chamber downstream. The cooling air in the cooling chamber is used to cool the web before steam is applied to the web from the steam chamber. This allows a sufficient volume of steam to be delivered to the web to thereby raise its moisture content to a desired level to thus achieve optimized calendering of the web.

Abstract: Described is a machine for manufacturing a continuous web, in particular a paper or cardboard web, the machine having a number of rolls that may include press rolls, drying cylinders, suction rolls, or the like. At least one transport belt is guided with the web around the rolls and is characterized by the fact that a metallic screen is guided between the web and the respective roll surface. The metallic screen may be formed of metal, formed as a metallized drying screen, or formed from metal and synthetic threads.

Abstract: The invention relates to a method and arrangement for moistening a substantially dry fiber web and subjecting the moistened web to heat and compression.

Abstract: Method to reduce adhesion of a damp fibrous material web, e.g., a paper or material web, to a rotating roll. The method includes producing a steam cushion between the rotating roll and the fibrous material web.

Abstract: The invention concerns a caring doctor blade for a paper/board machine, which blade comprises layers of fiberglass and carbon fiber and a caring layer as a rigid laminated structure, which caring layer comprises carbon fiber and grinding particles in direct vicinity of the carbon fibers. The orientation of the fiberglass layers is parallel to the longitudinal axis of the blade, and at least in some of the layers that contain carbon fiber the orientation of the carbon fibers is substantially diverging from the direction of the longitudinal axis of the blade. The invention also concerns a method for manufacture of a doctor blade for a paper/board machine by means of a pultrusion method.

Abstract: Machine for the manufacture of a fiber material web that includes a shoe pressing unit, a cylinder including one of a drying and tissue cylinder, in which shoe pressing unit and the cylinder are arranged to form at least one press nip, and a water absorbent carrier band. A water-impermeable pressing band is provided, in which the water absorbent carrier band and the water-impermeable pressing band are guided through the at least one press nip, and the fiber material web is adapted to pass through the at least one press nip with the water absorbent carrier band and the water-impermeable pressing band. The at least one press nip has a length in a web travel direction of less than or equal to approximately 60 mm. A pressure profile which results over the press nip length has a maximum pressing pressure which is greater than or equal to approximately 3.3 Mpa.

Abstract: In a method at the end of the drying section of a paper machine, drying cylinders (1, 2) are arranged in two substantially horizontal cylinder rows, wherein the first drying cylinders (1) are placed substantially higher than the second drying cylinders (2). In the method, the web (W) to be dried is conveyed alternately between the cylinder rows of the drying cylinders (1, 2). Further in the method, the transfer of the web (W) between the drying cylinders (1, 2) is supported by a wire run arrangement, and the web is guided after the last drying cylinder (1, 2) of the drying section (A) by a transfer arrangement in between the rolls of a pair of rolls in the calender section (B) of the paper machine.

Abstract: An arrangement for improving the beginning of the drying section joined to a closed web transfer between the press section and the drying section in a paper machine. In order to achieve less fouling of the drying cylinder, that is, less formation of fluff, to achieve easier doctorability and better doctoring tolerance of the drying cylinder surface in the drying section, the surface of at least the first drying cylinder in the drying section has a coating which includes a thin preferably hard layer of ceramic material and/or metal ceramic and/or metal, to which the web will adhere weakly, and/or another softer material, to which the web will adhere weakly, is absorbed into the drying cylinder surface, whereby separation of the web from the surface of the drying cylinder is improved.

Abstract: Described is a machine for manufacturing a continuous web, in particular a paper or cardboard web, the machine having a number of rolls that may include press rolls, drying cylinders, suction rolls, or the like. At least one transport belt is guided with the web around the rolls and is characterized by the fact that a metallic screen is guided between the web and the respective roll surface. The metallic screen may be formed of metal, formed as a metallized drying screen, or formed from metal and synthetic threads.

Abstract: A calender press for use in a paper-making machine includes a top roll positioned adjacent to a nip and rotatable about a longitudinal axis thereof. The top roll has a length and circumferential perimeter. The length extends in the direction of and is longer than the width of the fiber web. The top roll is thermally compensated in a plurality of thermal zones which are adjacent to each other across the length of the top roll, whereby the perimeter of the top roll may be adjusted in a locally adjustable manner toward and away from the nip. A bottom roll is positioned adjacent to the top roll and defines the nip with the top roll. The bottom roll is rotatable about a longitudinal axis thereof and has a length and circumferential perimeter. The length extends in the direction of and is longer than the width of the fiber web. The perimeter is smaller at each longitudinal end of the bottom roll and larger at approximately a midpoint between the longitudinal ends, thereby defining a crowned bottom roll.