Abstract: A dryer group for drying a paper web moving in a running direction through a paper-making machine includes and upper tier and a lower tier. The upper tier and lower tier each include a plurality of rotatable cylinders for carrying the paper web. Each of the cylinders has an inner chamber. The plurality of cylinders for the upper tier and the lower tier each include at least two drying cylinders and at least one cooling cylinder. The at least one cooling cylinder is disposed downstream from the at least two drying cylinders, relative to the running direction of the paper web. The upper tier and lower tier also each include a plurality of carrier rolls, with each carrier roll being disposed adjacent to a pair of corresponding cylinders. An upper felt and lower felt are alternately carried by each of the cylinders and each of the carrier rolls of the upper and lower tiers, respectively.

Abstract: A device for threading a paper web from a dryer section to a finishing device situated after the dryer section in the running direction of the web including a rope threading arrangement. A leader strip is separated from the edge of the paper web in the dryer section and the leader strip is directed between a pair of ropes included in the rope threading arrangement. The leader strip is carried to the finishing device on support of the ropes. To effect the transfer of the leader strip from the drying wire to the rope, at the inlet side of the last drying cylinder in the dryer section, a rope gap is formed out of the ropes and the leader strip, which is supported by the drying wire thereat, is transferred by an air blowing into the rope gap. The leader strip is passed by the ropes over the last drying cylinder to the finishing device.

Abstract: A single tier drying section is disclosed for drying a web. The drying section includes a dryer and a felt guided about the dryer such that the web is disposed between the dryer and the felt for drying a first side of the web. A further dryer is disposed downstream relative to the dryer and a further felt is guided about the further dryer such that the web is disposed between the further dryer and the further felt for drying a second side of the web. A dryer transfer mechanism is used for transferring the web from the dryer to the further dryer.

Abstract: The invention relates to dryer assembly including a taper cutter device, which is disposed adjacent to and after a top felt dryer group of a paper making machine. The taper cutter may be arranged between a last dryer cylinder of the top felt dryer group and a subsequent web guide roll. Further, the taper cutter may be positioned to contact the material web after a transport belt has separated from the material web and before the material web is lifted off a last dryer cylinder surface. At least the final dryer cylinder and the subsequent web guide roll can be driven.

Abstract: A method for improving the rush transfer of a web, such as a tissue web, is disclosed. The method provides for greater angles of convergence and divergence of the carrier fabric and the transfer fabric at the point of transfer by deflecting the carrier fabric toward the transfer fabric using a deflection element, such as a roll, positioned opposite the vacuum transfer head. The greater angles of convergence and divergence minimize the potential for undesirable macrofolds being formed in the web during transfer.

Abstract: A machine for producing a sheet of material, e.g., a paper or cardboard sheet, including a pressing part having at least one pressing device and a dryer part that includes a plurality of dryer cylinders. A first dryer cylinder of the plurality of dryer cylinders may be disposed immediately adjacent to the pressing part to form transfer region therebetween. The sheet of material being directly transferred from a press roll of the pressing part to the first dryer cylinder. The first dryer cylinder being heated independently of the other plurality of dryer cylinders at a temperature to form a vapor layer between the first dryer cylinder and the sheet of material.

Abstract: Device for producing a material web in a dryer part that includes at least one dryer section having a plurality of cylinders including heated cylinders and cooled cylinders. The device may also include a porous dryer screen and a metal belt that may be guided with the material web in a meandering path alternatingly around the heated and cooled cylinders. At least one of the metal belt and the dryer screen being highly prestressed and the device may also include at least one of a heating installation and a cooling installation assigned to act on an area of a circumference of the plurality of cylinders in which the material web may be supported by the dryer screen and the metal belt.

Abstract: A drying cylinder comprises a cylindrical shell with head members at either end and is mounted for rotation about its central longitudinal axis. A gas fired burner assembly is mounted in the interior of the cylinder and comprises a plurality of burner segments which transmit heat to the shell by infrared radiation. The heat output of the burner segments are controllable as an assembly in unison or individually.

Abstract: The dryer section of a machine for manufacturing a paper web includes at least one and more usually a plurality of heatable drying cylinders, each of which is wrapped over a part of its circumferential surface by the web of material to be dried. A support belt is guided by guide rolls to wrap over a part of the circumference of each of the drying cylinders and over the web. A pressing device presses against the support belt to press the web of material against the drying cylinder. That pressing device may comprise a pressure box outside the support belt to which air or steam pressure is applied. The pressure box may include several zones either along the web path or transverse to the web path permitting different pressures to be applied. The pressing device may alternately comprise a plurality of pressing rolls extending transversely to the web axis and parallel to the drying cylinder axis and being biased against the support belt, e.g.

Abstract: A device for guiding a sheet of fibrous material to be dried and a support belt through a drying device. The device including an external suction box having first and second openings located adjacent a deflection roll and adjacent to a lift-off point associated with a first dryer cylinder, respectively. The external suction box also including a first and second aspiration conduit respectively associated with the first and second openings. The deflection roll may be aspirated by an external vacuum souce coupled to the external suction box. The fibrous sheet, through the support belt, may be assisted at the lift-off point by aspiration by a separate external vacuum source coupled to the second aspiration conduit.

Abstract: A method and device for drying a paper web in a dryer section having a number of successive dryer groups with a single-wire draw, and being situated after a press section of the paper machine. Each dryer group includes contact-drying cylinders arranged in a first row and reversing suction cylinders or equivalent suction rolls arranged in a second row, the rows being horizontal, diagonal or vertical rows. The paper web is dried by contact-drying cylinders from the side of its lower face across the entire length of the dryer section. The paper web is passed as a closed draw from one dryer group to the next group, and the paper web is guided, while it runs on the drying wire at the side of the outside curve, by the reversing suction cylinders having a curve radius selected in a range from about 250 mm to about 1000 mm.

Abstract: A drying section for a paper making machine. The drying section includes a plurality of single-tier dryer groups, optionally followed by one or more double-tier groups. To control curl in the final paper product, a moistening device extending over the width of the drying section is provided near the end of the single-tier dryer groups. The moistening device can be divided into various zones to control the profile of the paper. Alternatively, or in addition to the moistening device, a contact-less dryer such as a infrared dryer can be provided after the dryer section, upstream of a calendar section of the paper making machine. The moistening device can be provided to moisten the bottom or, optionally, the top side of the paper web. Where a double-tier dryer group is provided, to control curl the upper drying cylinders and the lower cylinders can be provided with different steam pressures to control curl. Alternatively, each of the cylinders can be individually controlled.

Abstract: The invention is directed to a drying section of a paper machine for drying a fiber web. The drying section includes a plurality of drying groups, with each drying group having a plurality of heatable drying cylinders and a continuous hold-down belt. The hold-down belt has a longitudinal tension which biases the fiber web against the drying cylinders. The plurality of drying groups include at least one high-pressure group comprising a single-row drying group having one row of drying cylinders and one row of corresponding deflection rolls. The high-pressure group has a corresponding hold-down belt with a longitudinal tension which is at least 10 kN/m.

Abstract: When a new roll is changed in an off-machine coating line into the unwinder, problems are encountered in matching the tension of the web received from the expiring roll to that to be paid off from the new roll. Differences in web tension cause web breaks during roll change. To avoid this, the web is supported at the unwinder, and subsequently, at the following dryer cylinder group by a support felt that equalizes differences in web tension. The web received from the first roll is spliced to the tail of a second, full roll by pressing the web received from the first roll against the web of the second roll via the support felt by a splicing roll. Next, the web is fed supported by the felt to a dryer cylinder group including VAC and steam cylinders where the damp web is dried for subsequent coating.

Abstract: A papermaking machine uses a low pressure water jet mounted on a pneumatic actuator for movement at least as fast in the cross machine direction as the paper web moves in the machine direction for a distance of 2 to 12 inches. The jet rapidly cuts a tail with a blunt edge of 2 to 12 inches wide from the web. The actuator is mounted on a screw or belt driven carriage to traverse the web and expand the tail after it has been threaded through the dryer section until the tail encompass the entire web and thus completes the threading process. A controller coordinates an air jet positioned beneath a doctor blade and a vacuum suction roll which engages the last press roll. The air jet and vacuum suction roll are actuated when the blunt end of the tail engages the doctor blade. In this way a tail with little or no streamer is formed and blown onto a dryer fabric supported on a vacuum suction roll which leads the tail into a single tier dryer section.

Abstract: An apparatus for stabilizing a low-strength sheet having a width and a top surface and moving in a first direction at a rate sufficient to entrain air. The apparatus includes an airfoil adapted to extend along the top surface of the sheet. The airfoil, in turn, includes:a bottom surface adapted to extend along a portion of the top surface of the sheet;a first surface extending a first distance from the bottom surface at a first juncture;a second surface extending a second distance from the bottom surface at a second juncture; anda top surface extending from the first surface at a third juncture to the second surface at a fourth juncture. The first distance in general is less than the second distance.

Abstract: A drier section for drying a continuous web, particularly a paper web produced by a paper manufacturing machine. The drier section may include at least one single-row drier group with a plurality of drier cylinders and a plurality of guide rollers. The continuous web may guided, together with a continuous felt, in a meandering manner through the drier section. The drier section may also include a plurality of additional drier cylinders and a separate felt guided by additional guide rollers for guiding the continuous web around the drier cylinders of the single-row drier group and around the additional drier cylinders. The number of the additional drier cylinders may be less than the number of drier cylinders disposed within the single-row drier group.

Abstract: The invention is directed to a dryer section for an apparatus to produce webs of material, such as paper, carton or cardboard which shall consist of a number drying cylinders and carrier rollers, at least one dryer group which shall include at least one conveyer bend to direct the continuous material web along a meandering path around these drying cylinders and carrier rollers, and with at least one pressure cylinder to compress or smoothen the web of material. The pressure cylinder is located within the dryer group 3, 30 or 130, respectively, such that it is located within a region that is contained within the second and the second-to-last dryer cylinder of the dryer group.

Abstract: A paper making machine comprises a press followed by an adjoining drying section having a plurality of dryer groups. Each dryer group comprises only one row of dryer cylinders and one row of suction rolls then therebetween. The press section in each of the dryer groups has a respective variable web speed drive. A speed control device controls the drive such that a positive difference in speed is always present between the first dryer group and the press and also between the second dryer group and the first dryer group. Open draws may be defined between at least some of the dryer groups.

Abstract: A drying section for drying a traveling web of paper, which has successive drying groups each having drying cylinders, a felt or wire belt supporting the traveling web and resting against the drying cylinders, and guide rolls serving for the guiding of the web to be dried and of the felt or wire belt. The guide rolls are so arranged that the traveling web is guided in meandering form in the transfer region between two successive drying cylinders associated with different felt or wire belts. The transfer region is between the felts of two successive drying groups or the transfer region is between two felts in the two rows of a two tier drying group.

Abstract: In a dryer section comprised of several drying groups, and particularly an alternating single tier dryer section, one of the bottom felted drying groups is arranged with respect to the paper machine floor so at least the rotating shafts at the axis of the drying cylinders of the one drying group are below the paper machine floor. The guide rolls of the bottom felted drying group and of an adjacent top felted drying group may be in one horizontal shaft plane above the paper machine floor. An intermediate floor is provided beneath the main machine floor and the bottom of the basement beneath the one drying group. Easier access to the drying cylinders and elements of both top felted and bottom felted drying groups is obtained.

Abstract: In a drying section of a paper making machine, the paper web is conducted through a plurality of single tier dryer sections and then transferred to at least one final double tier dryer section for completing the drying process. The paper web is threaded through the open draw between the single tier dryer sections and the double tier dryer section and through the open draws between the lower cylinders and the upper cylinders in the double tier dryer section by use of air jets which blow at the paper web from opposite sides thereof. The air jets include at least one jet which blows in a direction generally opposite to that of the paper web.

Abstract: An improved two-tier, single-felted dryer section has an upper tier of spaced apart dryer drums and a lower tier of spaced apart dryer drums. The section includes at least one dryer drum group consisting of a first and second adjacent drum in one tier, a third drum in the other tier located between the adjacent first and second drums, and two reversing rolls positioned one on each of the opposite sides of the third drum. A felt-supported paper web follows a serpentine path about the dryer drums and reversing rolls. As a result, the felt-supported web passes through the dryer drum group with the web in direct contact with each of the three dryer drums in the dryer drum group.

Abstract: A method and device for contact drying a paper web, wherein the paper web is dried initially in a number of successive groups with single-wire draw by pressing the paper web via drying wires of each groups against the heated faces of the drying cylinders and by guiding the paper web on support of the same drying wire from one drying cylinder onto the next drying cylinder over the reversing suction cylinders or rolls in each group with single-wire draw. In the groups with single-wire draw, the paper web is dried to a first dry solids content, after which the paper web is dried directly further by a single group with twin-wire draw to a second dry solids content, after which the paper web is dried further to its final dry solids content by a single normal group with single-wire draw. The limits of the first and second dry solids contents are selected so that, in the middle or in the beginning of the range, the tear strength index and the breaking strength index of the web are at their maximum.

Abstract: In a drying section of a paper making machine, the paper web is conducted through a plurality of single tier dryer sections and then transferred to at least one final double tier dryer section for completing the drying process. The paper web is threaded through the open draw between the single tier dryer sections and the double tier dryer section and through the open draws between the lower cylinders and the upper cylinders in the double tier dryer section by use of air jets which blow at the paper web from opposite sides thereof. The air jets include at least one jet which blows in a direction generally opposite to that of the paper web.

Abstract: A paper-making process control system is provided for a paper making machine to simulate a web drying operation performed by the drying sections of the paper machine, in order to enhance the reliability of controlling operation in the web product grade change and to reduce the time necessary for the grade change. In the control system, when a web product change is carried out during the paper-making process by passing a web (WE) along with a canvas belt (14b) around a steam-heated drums (14a) for the drying of the web (WE), the control system describes heat balance among the steam-heated drums(14a), the web (WE), and the canvas belt (14b) by heat balance equations on an assumption that there is no temperature differential in the temperature of the circumferential portion of each steam-heated drum (14a), and adjustably regulates supply of steam to the respective steam-heated drums (14a) on the basis of the heat balance equations to thereby bring a moisture content of the web (WE) to a desired value.

Abstract: A device is arranged in the drying section of a papermaking machine for reducing the effects of the tendency of a paper web (4) to adhere to a drying cylinder (1) as it passes from the drying cylinder to a subsequent guide roll (2). In the drying section, the paper web (4), supported by a drying fabric (5), is conducted alternatingly over a plurality of drying cylinders (1) and guide rolls (2). A blow box (6) is arranged in the transition portion (A) and has a wall (7) extending in parallel with the drying fabric (5) so as to form a narrow air gap (8) between the wall and the drying fabric. The blow box (6) comprises nozzle (12) having a slot-shaped opening for ejecting a well-defined air jet (P1) towards the drying fabric (5) away from the air gap (8). The nozzle (12) is directed such that its center plane intersects the circumferential surface of the drying cylinder (1) along a first straight line positioned upstream of a second line, along which the paper web (4) leaves the drying cylinder (1).

Abstract: An unrestrained drying capability is added to an existing series of rotating drying cylinders in a cost- and space-efficient manner to enhance cross-directional (CD) stretch and tensile energy absorption (TEA) in a paper web such as for sack kraft grade paper. High-intensity air glide drying devices are adapted for use in a variety of configurations to provide different levels of unrestrained drying capacity for a pre-existing series of rotating drying rollers. The air glide drying devices carry the paper web on a cushion of air which is heated preferably to 500.degree.-850.degree. F. The sheet moisture content of the paper web during heating in the unrestrained drying section decreases by at least approximately 5%, with an evaporation rate of approximately 15-30 lbm/hr/ft.sup.2. A preferred temperature range of the paper web upon entry to the air glide drying device is 160.degree.-210.degree. F. A pre-heater such as a convection or infrared heater may optionally be employed.

Abstract: A drying section of a papermaking machine is constituted of a plurality of top-felted single-tier drying section which terminate with one or at most two two-tier sections which are both top-felted. The invention allows broke to fall by gravity, greatly facilitating broke removal and recycling. Moreover, the location of the double-tiers at the end of the drying sections affords opportunity for controlling curl.

Abstract: A three row drying cylinder group for a drying section of a paper machine or the like. The bottom cylinder row felt only passes through the bottom row. The top cylinder row felt passes from the top row, wraps the first middle row cylinder as a deflection element, passes over the next top row cylinder, and then is guided so that the opposite side of the top felt passes the next middle row cylinder and is guided back to the top row to alternate between the two ways of passing the middle row cylinders. Those middle row cylinders which are deflection elements may be heated or not and may deliver suction or vacuum to hold the web to the felt.

Abstract: A drying section of a paper machine includes a plurality of individual drying groups, wherein the drying cylinders of a drying group are served by 2 respective dryer wire or felt that passes over drying cylinders of the drying group and presses a web to be dried against the surface of the drying cylinders. The invention is adapted for either single tier or double tier drying groups. At least one press roll is disposed between and separates two of the drying groups. In one embodiment, the at least one press roll forms a nip with the adjacent drying cylinder, either upstream or downstream, to define a dewatering nip through which the web passes. A dewatering belt passes over the press roll in the nip. The wire for a respective drying group is guided away from the dewatering nip so that only the web and the dewatering belt pass through the press nip. In alternate embodiments, two press rolls may be disposed between the adjacent drying groups, and the two press rolls define a press nip between them.

Abstract: A hood for a wire part and/or a press section in a paper/board machine including walls and a ceiling which form a closed hood around the wire part and/or press section, air-conditioning or another air-control system being arranged in connection with the hood. The hood walls have outer and inner walls which define an air duct therebetween for passing a replacement air flow into the interior of the hood, preferably toward a middle area of the paper machine, through openings in the inner wall, the replacement air keeping the interior of the hood substantially dry and clean. The walls of the hood include a vertical side wall at the driving side, which wall is preferably fixed, and a tending-side vertical side wall and a ceiling formed as a single wall which is preferably L-shaped and displaceable. The displaceable hood wall at the tending side has two parts so that the first hood wall is placed by the wire section and the second hood wall is placed by the press section.

Abstract: A method and device for contact drying a paper web, wherein the paper web is dried initially in a number of successive groups with single-wire draw by pressing the paper web via drying wires of each groups against the heated faces of the drying cylinders and by guiding the paper web on support of the same drying wire from one drying cylinder onto the next drying cylinder over the reversing suction cylinders or rolls in each group with single-wire draw. In the groups with single-wire draw, the paper web is dried to a first dry solids content, after which the paper web is dried directly further by a single group with twin-wire draw to a second dry solids content, after which the paper web is dried further to its final dry solids content by a single normal group with single-wire draw. The limits of the first and second dry solids contents are selected so that, in the middle or in the beginning of the range, the tear strength index and the breaking strength index of the web are at their maximum.

Abstract: A method and device for drying a paper web wherein the paper web is supported on a drying wire without long open draws of the web. The paper web is contact-dried by pressing it with the drying wire onto a face of a contact-drying cylinder whose diameter is greater than about 1.5 m on a sector b whose magnitude is greater than about 180.degree.. The web is evaporation-dried as blowing-on drying and/or as through-drying by means of high-velocity drying-gas jets applied to the web on the drying wire on the face of the following large-diameter cylinder whose diameter is greater than about 2 m on a sector a having a magnitude greater than about 180.degree. while the web is on the side of the outside curve. The web to be dried is passed over a sector c of the suction roll which is subjected to negative pressure while the web is supported on the drying wire at the side of the outside curve. The magnitude of the sector of the suction roll has a magnitude greater than about 160.degree.

Abstract: A dry unit of a dry end of a machine for producing a material web and including at least one drying cylinder and a plurality of dry felts parsing around the dry cylinder one above another, with at least two of the dry felts being lifted off the dry cylinder at different circumferential positions of the two dry felts on the dry cylinder.

Abstract: An arrangement for cutting the leader of the web in a paper or board machine in the dryer section of the machine by a jet of pressurized water. The web is placed against the drying wire when it is being cut, and the jet is directed at the web from the free side of the web. The water jet pressure used is from about 40 bar to about 400 bar, preferably from about 100 bar to about 350 bar, which is produced by an ordinary pressure washer.

Abstract: An on-line coater apparatus is disclosed for coating a web of paper. The apparatus includes a dryer section having a plurality of single-tier dryer groups, each successive group drying an alternate side of the web, the web being restrained against cross-machine directional shrinkage during passage through the plurality of dryer groups. A further single-tier dryer group is disposed downstream relative to the plurality of groups such that the web extends in an open draw between the plurality of groups and the further group. A tail cutter is disposed adjacent to the open draw for cutting a tail from the web for subsequent threading through the further group. A calender is disposed downstream relative to the further group for calendering the dried web. A coater is disposed downstream relative to the calender for coating one side of the web, and a single-tier coating dryer group is disposed downstream relative to the coater for drying the coated one side of the web.

Abstract: A method and apparatus for cutting a paper web (W) in a group of drying cylinders provided with single-wire draw (13) in a paper machine or a finishing machine. The drying wire (13) is separated from the paper web (W) by one or more guide rolls (14a, 14b) thereby creating a open draw (W.sub.0) for the web (W). The cutting of the paper web (W) is carried out at the open draw (W.sub.0) of the web (W). After the open draw (W.sub.0), the drying wire (13) and the web (W) are rejoined on the surface of the following leading or drying cylinder (11). Preferably, two guide rolls (14a, 14b) are utilized whereby the first roll is disposed so that the drying wire (13) supports the web (W) up to the location of the guide roll (14a), which is followed by an open draw (W.sub.0) of the web. The drying wire (13) is returned onto the following leading or drying cylinder (11) with the second guide roll (14b).

Abstract: A paper machine comprising a single tier drying section including at least two dryer groups is disclosed. In one group, the axes of rotation of at least two consecutive drying cylinders lie substantially in a plane, and the axes of rotation of the vacuum rolls are disposed below the plane of dryer cylinders. In the next group, the axes of rotation of at least two consecutive drying cylinders lie substantially in a further plane which is non-coplanar with the plane defined by the dryers of the first dryer group. The vacuum rolls of the second dryer group have their axes of rotation disposed above the further plane. The dryer transfer which transfers the web from one dryer group to the next one includes a joint run of the felts of the respective dryer sections and a vacuum roll at the downstream end of the joint run. The joint run receives the web between the felts when the web passes through the joint run.

Abstract: A drying section for a paper making machine. The drying section includes a plurality of single-tier dryer groups, optionally followed by one or more double-tier groups. To control curl in the final paper product, a moistening device extending over the width of the drying section is provided near the end of the single-tier dryer groups. The moistening device can be divided into various zones to control the profile of the paper. Alternatively, or in addition to the moistening device, a contact-less dryer such as a infrared dryer can be provided after the dryer section, upstream of a calender section of the paper making machine. The moistening device can be provided to moisten the bottom or, optionally, the top side of the paper web. Where a double-tier dryer group is provided, to control curl the upper drying cylinders and the lower cylinders can be provided with different steam pressures to control curl. Alternatively, each of the cylinders can be individually controlled.

Abstract: A single tier drying section is disclosed for drying a web. The drying section includes a dryer and a felt guided about the dryer such that the web is disposed between the dryer and the felt for drying a first side of the web. A further dryer is disposed downstream relative to the dryer and a further felt is guided about the further dryer such that the web is disposed between the further dryer and the further felt for drying a second side of the web. A dryer transfer mechanism is used for transferring the web from the dryer to the further dryer.

Abstract: A limiting orifice through-air-drying apparatus for papermaking or other absorbent embryonic webs. The apparatus has a first zone and a second zone. The first zone is maintained at a differential pressure less than the breakthrough pressure, while the second zone is maintained at a differential pressure greater than the breakthrough pressure. The residence time of the embryonic web to be dried with the apparatus is maintained at preferably less than 35 milliseconds on the first zone. Using the dual zone system described above, the overall energy required to run the apparatus can be reduced.

Abstract: The paper dryer section has a single tier of all top felted dryer rolls seven to nine feet in diameter. Air caps are employed over the dryer rolls to simultaneously dry both sides of the web to prevent curl and to increase drying rates. The air caps employ blown air at a temperature of 200-1,000 degrees Fahrenheit and air speeds of 8,000-40,000 feet per minute. The felt employed is foraminous with a permeability of between 300-1,500 cubic feet per minute per square foot and is designed to withstand peak temperatures of up to 1,000 degrees Fahrenheit and average temperatures of between 500-600 degrees Fahrenheit. A single dryer roll, or more advantageously, two vacuum rolls in a vacuum box are disposed between the dryer rolls to maximize the circumferential wrap of the web and, at the same time, support and transport the web between dryers.

Abstract: In the initial region of the dryer section at least one of the dryer groups (23) is developed as a single-felt dryer group in which a single endless felt (F) and the web (9) travel alternately over cylinders (73) and guide suction rolls (73'). In the final region of the dryer section there is present at least one double-felt dryer group (24) in which a web (9) travels alternately over lower (74) and upper (74') cylinders. The single-felt group (23) has an automatic ropeless tail guide device (76, 79) for the threading of the so-called tail. In the double-felt dryer group (24) an automatic ropeless tail guide device (77, 78) is also present.

Abstract: A drying section for a paper making machine. The drying section includes a plurality of single-tier dryer groups, optionally followed by one or more double-tier groups. To control curl in the final paper product, a moistening device extending over the width of the drying section is provided near the end of the single-tier dryer groups. The moistening device can be divided into various zones to control the profile of the paper. Alternatively, or in addition to the moistening device, a contact-less dryer such as a infrared dryer can be provided after the dryer section, upstream of a calender section of the paper making machine. The moistening device can be provided to moisten the bottom or, optionally, the top side of the paper web. Where a double-tier dryer group is provided, to control curl the upper drying cylinders and the lower cylinders can be provided with different steam pressures to control curl. Alternatively, each of the cylinders can be individually controlled.

Abstract: A dryer section in a paper machine which comprises a number of dryer groups, each having drying cylinders, reversing cylinders arranged between adjacent pairs of drying cylinders and a wire which presses the web against heated cylinder faces of the drying cylinders whereas the web remains at the side of the outside curve on the reversing cylinders. The dryer groups are arranged in two or more stories. Some of the dryer groups in the dryer section are placed in the basement spaces underneath the machine hall level, and some of them are placed on the machine hall level.

Abstract: A method and device for drying a paper web in a dryer section having a number of successive dryer groups with a single-wire draw, and being situated after a press section of the paper machine. Each dryer group includes contact-drying cylinders arranged in a first row and reversing suction cylinders or equivalent suction rolls arranged in a second row, the rows being horizontal, diagonal or vertical rows. The paper web is dried by contact-drying cylinders from the side of its lower face across the entire length of the dryer section. The paper web is passed as a closed draw from one dryer group to the next group, and the paper web is guided, while it runs on the drying wire at the side of the outside curve, by the reversing suction cylinders having a curve radius selected in a range from about 250 mm to about 1000 mm.

Abstract: A limiting orifice through-air-drying apparatus for papermaking or other absorbent embryonic webs. The apparatus has a first zone and a second zone. The first zone is maintained at a differential pressure less than the breakthrough pressure, while the second zone is maintained at a differential pressure greater than the breakthrough pressure. The residence time of the embryonic web to be dried with the apparatus is maintained at preferably less than 35 milliseconds on the first zone. Using the dual zone system described above, the overall energy required to run the apparatus can be reduced.

Abstract: limiting orifice through-air-drying apparatus for papermaking or other absorbent embryonic webs. The apparatus has a first zone and a second zone. The first zone is maintained at a differential pressure less than the breakthrough pressure, while the second zone is maintained at a differential pressure greater than the breakthrough pressure. The residence time of the embryonic web to be dried with the apparatus is maintained at preferably less than 35 milliseconds on the first zone. Using the dual zone system described above, the overall energy required to run the apparatus can be reduced.

Abstract: Apparatus and method for drying a fibrous web. The apparatus comprises a plurality of drying cylinders arranged in groups from a first group to a last group, the web passing sequentially from the first group to the last group, each group having a single felt, the drying cylinders having vacuum transfer rolls arranged therebetween for guiding the fibrous web from one drying cylinder to the next drying cylinder, the vacuum transfer rolls being coupled to a vacuum source by a vacuum duct system, the duct system providing vacuum to the vacuum transfer rolls such that the vacuum level decreases from the first group to the last group. The vacuum level is preferably below about 1500 Pa, and in particular, in the range of about 100 to 1000 Pa.