摘要:
A method and apparatus are set forth for controlling and actuator in a moving web manufacturing process. The method includes: (1) measuring a plurality of actuator profiles and in response generating nominal response models thereof; (2) generating a multivariable profile prediction based on the nominal response models; (3) generating a multivariable control target based at least one of the actuator profile; and (4) adjusting control of the actuator by minimizing error between the multivariable control target and the multivariable profile prediction.
摘要:
A method and apparatus are set forth for controlling an actuator in a moving web manufacturing process, comprising measuring a plurality of actuator profiles and in response generating nominal response models thereof; generating a multivariable profile prediction based on the nominal response models; generating a multivariate control target based at least one of the actuator profiles; and adjusting control of the actuator by minimizing error between the multivariate control target and said multivariate profile prediction.
摘要:
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).
摘要:
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.
摘要:
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).
摘要:
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.
摘要:
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).
摘要:
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.
摘要:
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.
摘要:
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.