In present-day reel-ups and intermediate reel-ups (rereelers) and slitter- winders, the reeling or winding is controlled indirectly by adjusting reeling parameters (linear load, web tension and circumferential/reeling force). The adjustment is typically conducted with a special program.

The main objective of the reeling is to reel a roll from a continuous paper web, so that the roll meets the requirements set by the reeling process and further processing for processability and thereby for the structure of the roll as well as for the paper quality.

The properties of the web affect the quality of the roll. For example, the most common reeling problem caused by a poor web tension profile is the wrinkling of slack sections of the web, typically edges, in the reeling nip/s, because the web is longer by the slack section than by the tense section. The slackness of the edges also produces a poor edge-zone structure in the roll, and results in edge rolls of poor quality, which are difficult to be wound by means of slitter-winders and which pose problems when used for example in printing machines. If the web tension profile is very fluctuating or e. g. one-sided, it can lead to the use of a high web tension to be quite sure, which loads the tense sections of the web more and increases the number of web breaks.

The structure of the roll is affected by manipulated variables of the reeling process, which typically include the linear load of the reeling nip, the circumferential force, and the web tension. The reeling of the paper web and its control by means of different variables are described for example in Finnish patent 89701 and in the corresponding European patent 483093. The control of the paper making process in a paper machine is also discussed more extensively in Finnish patent 94066, and in the corresponding U. S. patent 5649448. Here, a tension profile measurement provides information which is used to adjust the actuators which precede the measurement and affect the other

transverse profiles of the web. Furthermore, publication JP-A-58162458 discloses a slitter-winder, in which the web is wound to form customer rolls. Here, the web tension is measured after unwinding, and it is displayed in a computer terminal, wherein the operator of the machine can set the values used in the unwinding to optimum.

The purpose of the invention is to present a reeling method, in which the properties of a web which is brought to reeling are better taken into account either in the reeling up of a full-width web or when winding a web to narrower customer rolls. To attain this purpose, the method according to the invention is primarily characterized in what will be presented in the characterizing part of the appended claim 1.

The invention comprises a control method for the reeling or winding process (e. g. reeling-up/intermediate reeling (rereeling), slitting/rewinding), in which method a web tension profile measurement is utilized to adjust the reeling or winding parameters and thereby the structure of the reel or roll to be reeled up or wound. The web tension profile is obtained in connection with the reeling up of a full-width web, i. e. web produced by a paper machine or a finishing machine for paper that has undergone a series of processing stages, in other words, it is possible to utilize the web tension profile information measured from the full-width web (the width of which, depending on the machine width, is several meters, typically over 4 meters). The variables to be adjusted in the reeling include for example the linear load of the reeling nip, the linear load profile, the center/circumferential drive and the web tension, or one or some of these. According to one embodiment, it is possible to profile a manipulated variable of the reeling or a factor affecting the web. For example the control of a spreading device, such as a spreader roll, preceding the reeling cylinder, also alleviates the problems of wrinkling in the reeling nip. By an active nip profile adjustment, it is also possible to control the effect of such local tension profile deviations on the structure of the web which are situated closer to the center of the web in the tranverse direction. It is also possible to adjust a suitable variable as a whole, for example the web tension level to reduce web breaks.

In slitter-winders, the need to adjust the structure of the roll due to a poor tension profile often pertains to edge rolls or individual rolls in the middle of the web. Center-drive slitter-winders enable a very accurate adjustment of the structures of individual rolls in each winding station.

In the winding effected by the slitter-winder, it is possible to use e. g. the tension profile information from the reel-up of a full-width web of the preceding process stage to adjust the reeling parameters.

The apparatus in the reeling of a web, in turn, is characterized in what will be presented in the characterizing part of the appended claim 13.

The apparatus comprises at least a measuring device for the web tension profile, and a data processing unit which is arranged to process the information on the web tension profile and to control one or more controllers of the reeling or winding.

In the following, the invention will be described in more detail with reference to the appended drawings, in which Fig. 1 shows the principe of the method according to the invention in a diagram attached to a side-view of a reel-up, Fig. 2 shows the application of the method in a reel-up structure, Fig. 3 shows the application of the method in another reel-up structure, and Fig. 4 shows the structure of the reel-up of Fig. 3 widthwise.

Fig. 1 shows a reel-up which is arranged to form a machine reel R of a continuous full-width web W passed from the preceding paper machine sections. Instead of an actual paper making machine, the apparatus in question may also be a finishing machine for paper. The web travels via a tension profile measuring device 1 and a spreading device 11, which immediately precede the reel-up, to a reeling cylinder 2 of the reel-up, winds around it within a given sector and ends up onto the reel R via a reeling nip N. The reel is formed in a known manner around a reeling shaft, i. e. a reel spool 3, and the reel spool 3 is loaded with an ajustable force towards the reeling cylinder 2 in order to provide the

reeling nip N with the desired linear load. The linear load can also be produced by loading the reeling cylinder, which is supported in a mobile manner, against a substantially stationary rotatable reel R (reel spool 3). The load is accomplished in practice with a force device 4, which is arranged in a power transmitting connection with the ends of the reel spool 3, for example by means of a reeling carriage 5 which is arranged mobile in the frame. The reeling cylinder 2 and the reel spool 3 are equipped with center drives, known as such, whose drive devices are marked with reference numerals 6 and 7 respectively. When the reel R grows, the carriage 5 simultaneously moves further away from the reeling cylinder 2, and when the reel has become full, it is removed and a new empty reel spool is brought to the reel-up by means of arrangements known as such, which will not be described in more detail in this context.

The force device 4 is typically an actuator which is driven by means of a pressurized medium and whose force can be adjusted by altering the pressure of the pressurized medium. Primarily hydraulic, but also pneumatic cylinders are possible.

As the device 1 for measuring the tension profile of the web W, it is possible to use known devices which can conduct on-line measuring of the by-passing web. One such device is presented in Finnish patent 80522 and in the corresponding US patent 5052233.

Furthermore, Fig. 1 shows a data processing unit 10, which is arranged to collect measurement data from different locations via data transmission lines, for example input messages I2 and I3 from the center drives 6 and 7, which messages can be for example the values of torque and rotational speed which are compared with the set value in the adjustment; and an input message 14 from the force device 4, such as a pressure which indicates the linear load in nip N. The unit 10 can be supplied with input messages also from other parts of the process, for example from the process stages before the reeling, these input messages and the corresponding data transmission lines being marked with letters Ix and Iy.

Especially the data processing unit 10 is arranged to receive an input message I1 from the device 1 which continuously measures the tension profile, the input message I1 containing information on the tension profile of the web W that enters the reeling process.

The data processing unit 10 is arranged to process input messages and to control different reeling parameters. For this purpose, the different controllers are provided with data transmission lines. An output message 01 controls the force generated by the force device 4 and thereby the linear load in the reeling nip N; an output message 02 controls the effect directed to the web W by the spreading device 11, e. g. the bowing of the spreader roll; an output message 03 controls the drive of the reeling cylinder 2; and an output message 04 controls the drive of the reel spool 3. Other possible output messages are marked with the letter Ox. Thus, an automatic control of the reeling parameters is achieved according to predetermined principles.

On the basis of the tension profile information, a factor affecting the web W is profile in the transverse direction of the web W in particular, by utilizing the methods available. As for the spreading device 11, this means that the web W is guided (spread) with the spreading device, which can be a spreader roll, a turning shoe functioning by means of air foils, or another corresponding spreading device.

Profiling can be performed in the reeling nip N as well. In the reeling, there are several ways of affecting the load distribution in the reeling nip N in the lateral i. e. transverse direction of the web W on the basis of information received on the tension profile. By altering the load effected through the ends of the reel spool, a certain load distribution is always produced. Here, it is also possible to use a variable crown roll.

Fig. 2 presents a solution, in which the parts similar to the parts in Fig.

1 are marked with the same reference numerals. The reel-up is of such a type in which the linear load in the reeling nip N is affected by a so- called angle reeling in which the reel spool 3 is supported at its ends by arms 8 which are arranged pivotable in the vertical plane and are moved by an actuator 9, which sets the reeling angle a to a desired value. The angle a determines, in a known manner, the linear load in

the nip N due to the weight of the reel spool 3 and the web wound around it, in addition to which the load or relief force can be adjusted by means of force devices 4 which are fixed to the arms 8 and connected to the ends of the reel spool 3 and are capable of increasing or relieving the load. This so-called angle reeling solution is disclosed in Finnish patent 89701. By means of the angular position of the reel spool and the load/relief effected at the ends, it is also possible to profile the linear load.

Fig. 3 shows a reel-up type, a so-called belt support reel-up, in which the reeling nip N is produced by means of a belt and rolls system 12, which is pressed with a force device 13 against the reel R being formed. The belt can also comprise means 14 for adjusting the tension, whereby it is possible to adjust the tension of the belt in contact with the reel R. By means of the web tension profile information it is possible to adjust the load effected by the force device 13 and/or the means 14 for adjusting the tension (output message 01 and 01'). The reel spool 3 is supported by reeling rails 15, along which the empty reel spools 3 are also brought to a change position. Furthermore, Fig. 4 shows the structure of the reel-up widthwise. There are several belt and rolls systems 12 over the width of the web W and the reel R, and they are equipped with force devices 13 and means 14 for adjusting the tension of their own. The load effected by these devices and means can be set individually. Thus, the reeling nip N can be provided with the desired linear load distribution according to the measured tension profile.

The reel to be formed can be supported and loaded also in another manner than the one presented above. It is also possible to use other reel-up types besides those presented above. Corresponding ideas can well be applied in pressure roller reel-ups as well. The invention can also be applied in winders following the slitter, such as carrier drum winders. In connection with the slitter-winders, it is most advantageous to utilize the tension profile information of the web that is measured already in connection with the reeling of an intermediate reel formed of a full-width web, which tension profile information is stored in the central processing unit 10. By means of this stored information it is possible to control the aforementioned parameters in each winder following the slitter.

In this context, the reeling nip N refers to an area that more or less extends in the longitudinal direction of the web W, and in which there is a load, e. g. the point at which the mantle of the reeling cylinder is in contact with the reel, or the point at which the belt of a belt and rolls system is in contact with the roll R.

In winding after the slitter, it is still possible to monitor the web tension profile of each web running onto the respective roll by means of an on- line measuring device 1, and to correct the winding parameters of each roll when necessary.

The rolls that are delivered to a customer can be accompanied with the tension profile information of the corresponding web, stored in a suitable way, for example on a diskette to be read electrically or optically, or in the form of a digital bar code e. g. on a label or elsewhere in connection with the roll. The customer rolls that are wound after the slitter can be accompanied with the tension profile information of the web of the intermediate reel in the corresponding location in the transverse direction of the web, with the web tension profile information obtained in the winding of the customer roll itself, or with both of them in any of the aforementioned formats. The information that accompanies the customer rolls can contain the average value of the tension profile for the entire duration of the reeling/winding or more information, e. g. the variation of the tension profile as a function of time or the meters reeled or wound.

The invention is applicable for the reeling or winding of all web-like materials, especially paper web. In this context, the paper web refers to all continuous web-like materials that are produced of fibrous material, irrespective of their grammage.