Abstract: A method for controlling the moisture profile of a paper web or board web processed in a heated multi-roll calendar to optimize the qualities of the paper or board, especially gloss. The method is characterized in that the moisture measurement is carried out both on either surface of the web and as a through-measurement, and the measurement results thus obtained are specified by a thermodynamic model which calculates the moisture of the web in three layers, and that the results thus obtained are used for controlling the supply of moisture to the web.

Abstract: A paper web moistening device comprises several moistening nozzles (2) in the cross direction of a paper web for blowing water mist comprising air and water onto the paper web (3) surface. At least one means for removing water 5 mist and/or air from the vicinity of the paper web (3) surface is arranged be-tween the moistening nozzles. This means is arranged closer to the paper web (3) surface than the moistening nozzles (2).

Abstract: The moisture profile and/or moisture gradient of a paper web of at least SC quality paper is controlled in a paper machine comprising a calender (1) which has at least two roll stacks (21, 22; 31, 32), one stack has at least three rolls and another has at least five rolls. The web is moisturized to a desired pre-moisture content M1 by a pre-moisturizer (7) before the calender. At least one intermediate moisturizer (3) is arranged between two roll stacks moisturizes the web to a desired intermediate moisture content M2 before the last roll stack (31, 32), in which the web is dried to a desired final moisture value M3. For continuously controlling and optimizing the moisture profile and/or moisture gradient of the web, the pre-moisturizing W1 of the web is controlled by a pre-moisturizer (7) control parameter which corresponds to the final moisture value M3 of the web.

Abstract: In a paper/board or finishing/converting machine, a calender (1) comprises a number of rolls (2, 3) formed into a roll stack, and a number of lift-out rolls (4), which are arranged in such a way that the web (W) being treated travels from one calender (1) nip (N) to another via a lift-out roll (4). Between the calender (1) roll (2, 3) and the lift-out roll (4), the web (W) being treated is supported by means of at least one closing member (5, 5?, 6) not extending through the nip (N), which closing member is formed by a belt, wire or metal wire (7), which is arranged to travel via two or more guide rolls (4, 8).

Abstract: In the method for treating the surface of the web, liquid is added on the surface of a paper or paperboard web (W), possibly with other constituents. The absorbency of the surface of the paper or paperboard web is increased before liquid is brought on the surface of the web or simultaneously with bringing the liquid on the surface of the web. The method is used for wetting the surface of the web before calendering, or for coating the web in surface sizing or pigmenting. The absorbency of the surface is increased before bringing the liquid for example by means of a corona treatment, a flame treatment, an ozonization or by adding steam.

Abstract: A method and an arrangement for controlling evaporation and moisture in a multinip calender (10) when a continuous fibrous web (W) is calendered in calendering nips (1,_2,—3,—4,—5) placed one after the other before the fibrous web is wound on a reel-up/winder (9). With a view to making the net evaporation from and the final moisture content of the web (W) constant when the running situations in the calender (10) change, the web is passed in the calender from the outlet of at least one nip into an air-float chamber (20) of the turning airborne type.

Abstract: A method for managing the water sorption of a board by layered sizing is provided, such that the sizing of a central layer is effected with a hydrophobic and fast-curing adhesive, and the surface sizing in preparation for calendering is effected with an adhesive which is hydrophilic during its curing period, such that, during a surface wetting process, water sorption occurs substantially only into a topliner.

Abstract: Tension variations in the paper web on a paper machine are caused by successive draws and moisture fluctuations. Good strength properties require optimization of the draws. In addition, the tension variation induced by moisture must be minimized. The analysis of local modulus and the strain components can be used for determining optimal locations for profiling actuators in order to achieve good tension profile. Longitudinal strain components of the web, i.e. reversible elastic strain, permanent plastic strain and frozen-in strain relievable with water are continuously measured and determined and the variation of said longitudinal components is minimized by correcting the moisture content of the paper web in a dryer section of the paper machine and/or by optimizing the draws between dryer groups in the dryer section.

Abstract: A multi-roll calender for controlling the moisture gradient of a fibrous web and for enabling the manufacture of high quality paper grades, such as WFC, LWC-roto and SC-A by on- and off-line calendering. An on- or off-line multi-roll calender formed of separate sets of rolls is used for calendering, and the fibrous web (W) is subjected to intermediate moistening between the sets of rolls (A, B).

Abstract: A paper or board web (W) is calendered in at least one calendering nip (N1-N8), and the web (W) is moisturized before calendering. The web (W) is moisturized by means of liquid moisturization (20; 21) very close before at least one calendering nip (N1, N5). A calender for calendering a paper or board web has at least one liquid moisturizing calendering nip (N1-N8) and at least one device (20; 21) for moisturizing the web (W) is placed very close before at least one calendering nip (N1; N5).

Abstract: A multi-roll calender for controlling the moisture gradient of a fibrous web and for enabling the manufacture of high quality paper grades, such as WFC, LWC-roto and SC-A by on- and off-line calendering. An on-or off-line multi-roll calender formed of separate sets of rolls is used for calendering, and the fibrous web (W) is subjected to intermediate moistening between the sets of rolls (A, B).

Abstract: The invention relates to a method for minimizing tension variation in a paper web induced by drying of the web in a paper machine. Tension variations in the paper web are caused by successive draws and moisture fluctuations. Good strength properties require optimization of the draws. In addition, the tension variation induced by moisture must be minimized. The analysis of local modulus and the strain components can be used for determining optimal locations for profiling actuators in order to achieve good tension profile. In the method according to the invention, longitudinal strain components of the web, i.e. reversible elastic strain, permanent plastic strain and frozen-in strain relievable with water are continuously measured and determined and the variation of said longitudinal components is minimized by correcting the moisture content of the paper web in a dryer section of the paper machine and/or by optimizing the draws between dryer groups in the dryer section.

Abstract: A method for a multi-roll calender and a multi-roll calender for controlling the moisture gradient of a fibrous web and for enabling the manufacture of high quality paper grades, such as WFC, LWC-roto and SC-A by on- and off-line calendering. An on- or off-line multi-roll calender formed of separate sets of rolls is used for calendering, and the fibrous web (W) is subjected to intermediate moistening between the sets of rolls (A, B).

Abstract: A method and an arrangement for controlling evaporation and moisture in a multinip calender (10) when a continuous fibrous web (W) is calendered in calendering nips (1, 2, 3, 4, 5) placed one after the other before the fibrous web is wound on a reel-up/winder (9). It is characteristic of the invention that. with a view to making the net evaporation from and the final moisture content of the web (W) constant when the running situations in the calender (10) change, the web is passed in the calender from the outlet of at least one nip into an air-float chamber (20) of the turning airborne type.

Abstract: In a paper/board or finishing/converting machine, a calender (1) comprises a number of rolls (2, 3) formed into a roll stack, and a number of lift-out rolls (4), which are arranged in such a way that the web (W) being treated travels from one calender (1) nip (N) to another via a lift-out roll (4). Between the calender (1) roll (2, 3) and the lift-out roll (4), the web (W) being treated is supported by means of at least one closing member (5, 5′, 6) not extending through the nip (N), which closing member is formed by a belt, wire or metal wire (7), which is arranged to travel via two or more guide rolls (4, 8).

Abstract: In the method for manufacturing surface-treated printing paper, a paper web is first dried down to a target moisture of the surface treatment, and it is wetted again to the target moisture before the surface treatment. The rewetting to the target moisture is conducted on the web running to the surface treatment before a device effecting the surface treatment of the web, as seen in the travel direction of the web. Before re-wetting, the moisture profile of the web is adjusted in the drying section by wetting the web at a point which is located before the area of the heavy shrinkage (cd shrinkage area) in the travel direction of the web.

Abstract: The invention relates to a method for calendering a paper or board web, in which method the web (W) is calendered in at least one calendering nip (N1-N8), and in which method the web (W) is moisturized before calendering. In the method, the web (W) is moisturized by means of moisturization (20; 21) very close before at least one calendering nip (N1, N5). The invention also relates to a calender for calendering a paper or board web comprising at least one calendering nip (N1-N8) and at least one device for moisturizing the web (W). The device for moisturizing the web (W) is a moisturizing device (20; 21) and that the moisturizing device (20; 21) is placed very close before or in at least one calendering nip (N1, N5).

Abstract: In the method in moistening of a web, water is applied with a wetting device (2) in a predetermined point on the surface of a paper web (W) or the like passing by the point, and the web is thereafter passed to a calender (C). The liquid is applied at such an early stage that before the surface treatment, the fibres exposed to wetting in the paper web (W) or the like have the time to absorb it at least 80% of the amount of liquid they are capable of absorbing. The distance travelled by the web between the drying section and the calender is increased with rolls (1) which guide the web (W) along a winding path.

Abstract: A method and apparatus for manufacturing calendered paper in which the paper is calendered after drying. The paper is dried (D) sown to a moisture lower that the target moisture of calendering. The paper is run via wetting (1) to calendering, wherein at least one of the surface layer of the paper is wetted in the wetting in such that the moistening water is absorbed in the surface layer of the paper while at lest the central part remains substantially dry. From the paper wetted at least on one of its sides, gradient paper is manufactured by means of gradient calendering by restricting the paper-molding effect of the calender to the wetted surface layer in such a way that at least the paper is elastically restored substantially in its original state, whereafter the obtained gradient paper is reeled.

Abstract: A method and apparatus for producing calendered paper by an on-line manufacturing system comprising at least a paper machine and a multi-nip calender. The method comprises following steps: removing water from a formed paper web by pressing, drying the pressed paper web by at least one dryer, calendering the dried web by the multi-nip calender, measuring a cross-machine moisture profile or a variable relative thereto, and altering the moisture of the web so that the moisture profile of the web in the cross-direction is even when the web enters the first nip of the calender.