Abstract: A method for calendering a web such as a paper web in a multi-nip calender or supercalender, in which the web is passed through calendering nips formed by rolls placed in two or more stacks of rolls. The web is passed alternatingly from the corresponding calendering nip in each stack of rolls into the calendering nip in the following stack of rolls. In other words, the web is passed from a first calendering nip in a first stack of rolls to a first calendering nip in a second stacks of rolls, after the first calendering nip in the second stack of rolls to a second calendering nip in the second stack of rolls, from the second calendering nip in the second stack of rolls to a second calendering nip in the first stack of rolls, and after the second calendering nip in the first stack of rolls to further processing.

Abstract: A drying unit in a dryer section of a paper or board machine including a drying wire guided in a loop, a large-diameter impingement-drying and/or through-drying cylinder arranged inside the drying-wire loop and smaller diameter smooth-faced heated contact-drying cylinders arranged on top of the large cylinder and/or in the vicinity thereof and at both sides thereof. The impingement-drying and/or through-drying cylinder is placed in a space below the floor level of the paper machine hall and provided with an openable and closable blow hood so that the removal of broke out of connection with the hood takes place substantially by the force of gravity. The central axes of the contact-drying cylinders placed in the vicinity of the large cylinder are placed in the vicinity of, or above, the floor level of the paper machine hall. A curve sector of the paper web on the outer face of the drying wire over the large cylinder greater than about 180.degree..

Abstract: A slide disc seal for use in a roll of a paper or board making machine or finishing apparatus, which roll comprises a stationary axle (1) and a rotatable shell (2) with an end element (8) at each end and bearing elements (3) at each end of the roll. The slide disc seal comprises a circular sliding surface (10) on the end element (8), a chamber (18) on the other of the components (1) placed axially on the area of the sliding surface (10) and extending radially in relation to the sliding surface (10), and a ring-shaped sliding seal disc (15) having an inner edge, an outer edge and a lip seal (16) on one of the edges, the seal disc (15) being slidingly fitted within the chamber (18) so that the edge having the lip seal (16) is against the sliding surface (10) and the other edge of the seal disc (15) is within the chamber (18).

Abstract: A dry end of a paper machine and a method for drying paper in which a paper web to be dried is passed from a press section of the paper machine into a forward dryer section including only single-wire groups with normal single-wire draw. The web is dried from the side of its bottom face in the dryer groups in the forward dryer section. From the forward dryer section, the web is passed into a finishing section in which the web is coated/surface-sized by a coating/surface-sizing device and then dried in an after-dryer by passing through at least one dryer group that applies a normal single-wire draw. Thereafter, the web is calendered and passed to a reeling station. Curling of the web is controlled by the operation or construction of components and/or by assemblies and combinations formed out of these components provided in connection with the forward dryer section and/or the finishing section.

Abstract: An extended nip press is provided having an advantageous nip press shoe which generates less heat than conventional press shoes. The nip press shoe includes an inrunning land surface which may be planar or convex. At least one lubrication pocket is downstream of the inrunning land surface and defines a cavity for supporting lubricant to create a hydrostatic lubrication region with a flexible jacket. The pocket has a bottom surface which converges towards the flexible jacket in a downstream direction. The press shoe further includes an outrunning land surface downstream of the lubrication pocket for engaging the flexible jacket against the opposite convex press element at a downstream end of the extended nip press. The outrunning land surface has a radius of curvature greater than the radius of curvature of the convex press element, and is planar in one embodiment, to create an attenuated hydrodynamic lubrication region with the flexible jacket.

Abstract: A roll for a paper machine, in particular for a paper drying device, including an axle on whose support the roll revolves, and a surface construction connected to the axle by support members. The openness of the surface construction of the roll is higher than about 10%, preferably higher than about 20%, so that when the roll an effect is produced that sucks air inward into the roll whereby a flow of air through the roll arises. Also, a single-wire draw dryer group for a paper machine having two contact-drying cylinders and one reversing roll wherein a web to be dried is guided on support of a drying wire meandering from one drying cylinder onto the reversing roll and then onto the other drying cylinder so that on the drying cylinders, the web remains between the cylinder face and the drying wire and on the reversing cylinder, the web is situated at the side of the outside curve.

Abstract: The invention relates to a device and method in a paper machine for guiding a web and in particular in guiding a leader of the web. The device operates in a paper machine in the area between a center roll of the press section and a separate press nip in the press section. The separate press nip is formed between a smooth-faced upper roll and a hollow-faced lower roll. Around this lower roll, a lower felt of the separate press is placed and runs from a suction-transfer roll placed at the proximity of the center roll as a straight run into the separate press nip. At the initial end of the straight run of the felt of the separate press nip, in connection with the guide roll, air-transfer devices are arranged, by whose means a reduced pressure is produced at least across the width of the leader in connection with a closing inlet nip between the felt and the leader and/or in connection with an opening outlet nip defined between the guide roll and the straight run of the felt.

Abstract: A method for calendering a paper web, including the steps of passing the paper web through a calendering nip having a profile formed from a pair of calendering rolls, wherein at least one of the pair of calendering rolls includes a soft exterior face at least in the region of the nip, regulating the profile of the calendering nip to compensate for flaws in the paper web passing through the calendering nip including varying the properties of the soft exterior face locally in a direction transverse to the direction of the passing paper web concurrently with the passing step.

Abstract: A method in a dryer section of a paper or board machine for controlling curl of paper, in which steam treatment and/or moistening of the paper web is/are employed. The operations carried out in order to control the curl of the paper web are carried out in a number of stages when the web temperature is, during at least one stage, lower than 85.degree. C., preferably lower than 75.degree. C., and when the dry solids content of the web is in the range of K1-K2, wherein K1 is the ultimate dry solids content of the web -7% and K2 is the ultimate dry solids content +3%. The paper or board machine includes at least a headbox, a former, a press, and a dryer section in steam boxes or moistening devices are employed for control of the curl. There are at least two curl regulation devices to enable regulation of the curl in a number of stages, and/or the curl regulation devices are arranged to operate in an area in which the web temperature is, during at least one stage lower than 85.degree. C., preferably lower than 75.

Abstract: A roll for use in the production of paper having a frame and a roll coating produced by thermal spraying. The coating is sealed by crystals formed out of a sealing-agent solution after the elimination of water therefrom. A coating for a roll for use in the production of paper produced by thermal spraying and having pores. In order to seal the coating, a sealing agent is crystallized in the pores in the coating.

Abstract: A method for coating a paper or board web or the like (7) using a coating mix aerosol generated by means of an ultrasonic atomizer. The output power of a plurality of ultrasonic transducers (15) disposed proximate to a surface of the moving web (7) is passed via a vibrated beam (14) to a coating mix flow (2) flowing proximate to the web (5). Ultrasonic vibrations applied to the coating mix atomize the upper layer of the coating mix flow into an aerosol (11) which is emitted toward the web (7) and adheres thereto.

Abstract: A seal construction for a suction roll in a paper machine including a substantially U-section holder open toward an inner face of the roll mantle and a seal mounted in the holder and extending in the axial direction of the roll. The seal includes a frame part arranged within the holder and a wear part fixed to the frame part and placed against the inner face of the roll mantle. The seal construction also includes a loading hose for shifting the seal in the holder against the inner face of the roll mantle. In the interior of the frame part of the seal, an inner loading member is arranged to lock the frame part of the seal in contact with the holder so as to position the wear part of the seal in the desired position in relation to the inner face of the roll mantle.

Abstract: In a method for manipulating paper roll heads by a multi-axis robot (8), heads are picked-up and transferred by the robot (8) from multiple stacks in accordance with stored data concerning the height and position of each stack as well as the dimension characteristics of the articles in the stack. At initial start-up, or immediately after a shut-down, previously stored information on the position or height of the stacks is considered not known by or otherwise unreliable by the robot (8) controller. That is, when the operation of the robot (8) is halted to accommodate replacement or replenishment of the head stacks, the stored parameter data for all stacks is set unknown. In accordance with its operating program, the system operation is restarted, the robot performs a slow-speed approach toward an uncalibrated stack, measures the stack data, that is, calibrates the stack height and position, and thus can perform the next stack approach through a normal transfer cycle on the basis of the measured data.

Abstract: A method for determining the quality of the formation of a reel or roll of a paper or board web and controlling the reel or roll formation or subsequent processing of the reel or roll based on the determined quality of the formation of the reel or roll. An oscillation signal produced by impulses formed in a web reel or roll during reeling or winding and arising from relative movements of web layers and/or from damaging of the web is measured and optionally stored. The measured signal is stored in electrical form as a function of time, reel/roll diameter, or the length of the web. The stored values are used in the control of the formation of reel or roll or in subsequent unwinding, reeling or winding of the reel or roll.

Abstract: A method for arranging water circulation in a paper mill including a pulp manufacturing plant provided with a water circulation system, such as a TMP plant, and a paper machine provided with a water circulation system. In order to reduce the amount of fresh water supplied to the paper mill, a part of the amount of fresh water supplied to the paper mill is substituted for by water or waters cleaned locally from waters contaminated at the paper mill. The concentrate or concentrates obtained from the stages of water cleaning is/are utilized where applicable by arranging the concentrate(s) to flow upstream in relation to the raw-material flow for reuse at the paper mill. By means of these operations, the amount of contaminants circulating in the paper mill is controlled.

Abstract: A press roll for a paper or board machine, a method for manufacturing a roll for a paper or board machine and a coating composition for a roll which enable the roll to endure difficult corrosion conditions. An adhesion/corrosion-protection layer having a thickness of from about 150 .mu.m to about 300 .mu.m is applied onto the frame part of the roll by a high-velocity flame spraying technique. The adhesion/corrosion-protection layer contains a nickel-chromium alloy. A tight-ceramic layer having a thickness from about 50 .mu.m to about 150 .mu.m is applied onto the adhesion/corrosion-protection layer by a high-velocity flame spraying technique and includes from about 50% to about 100% of Al.sub.2 O.sub.3 and optionally includes up to about 50% of TiO.sub.2 and/or any amount of Al.sub.2 TiO.sub.5. A porous ceramic layer is applied onto the tight ceramic layer. The tight-ceramic layer may include only Al.sub.2 TiO.sub.5 instead of Al.sub.2 O.sub.3, with or without TiO.sub.2.

Abstract: An after-dryer and method for drying a surface-treated paper web in an after-dryer of a paper machine in which the web is first finished in a finishing section, i.e., surface-sized or coated, by a finishing device and then dried. In the after-dryer, the paper web is dried in at least one dryer group that makes use of single-wire draw and at the same time, the paper web is dried by an impingement-drying equipment arranged in connection with at least one cylinder or roll in the single-wire dryer group.

Abstract: A method and an arrangement for treatment of reject material separated at screening of fibre pulp prepared by grinding wood. In the method reject material is fed against the surface of a grindstone (3) of a pressure grinder immediately before a normal grinding zone (6). The arrangement comprises a reject feeding equipment (12) placed immediately before the normal grinding zone (6) through which the reject material is fed to be ground again.

Abstract: A method and apparatus for placing headers onto the ends of paper or paperboard rolls by inserting the headers into the tubular cavity formed by the overlapping rim of the roll wrapper to the roll end. The roll to be packaged is transferred to the header inserter station, a header of desired type for the roll is fetched from a header support shelf and delivered to a header inserter grabber of a header inserter assembly waiting in its delivery position. Next, the header is transferred by movement of the header inserter grabber into the tube formed by the wrapper overlap, and subsequently, the header is transferred against the end of the roll. The header is transferred into the wrapper tube by means of rotating the header inserter grabber about a shaft, which is offset from the transfer path of the roll and is aligned orthogonal to the longitudinal axis of the roll.

Abstract: A method for reducing the consumption of fresh water and energy in a paper mill in which fresh water is passed into the paper mill for various needs, and a cooling tower is utilized for cooling water heated in the papermaking process. All fresh waters or a substantial proportion of the fresh waters of the paper mill are introduced into the process through the water system of the cooling tower. The cooling tower includes at least one inlet for passing the water to be cooled into the cooling tower, nozzles for discharging the water that was passed in and that is to be cooled onto heat transfer faces, filler pieces and/or filler plates, which disperse the water to be cooled so as to increase the contact area between the water and the cooling air, at least one outlet for passing the cooled water out of the cooling tower, and blowers for blowing the cooling air through the cooling tower.