FI119806B - A method for utilizing the operating capacity reserve when rolling a fiber web - Google Patents

Description

1, 119806

The present invention relates to a method for utilizing a utilization capacity reserve 5 for winding a fiber web. The process described in the present invention can be particularly advantageously used in connection with web winding machines in which one or more fiber web rolls and / or rolls are formed from one fiber web roll.

In the paper industry web winding applications, many applications involve accelerating the roll to normal running speed or decelerating from it to stops or near stops. After finishing, the fibrous web roll is unwound for either the coating unit, supercalendering, soft calendering for intermediate rewinding, rewinding or longitudinal cutting. In all of these targets, the fiber web reel should be accelerated to the speed required by the finishing device as quickly as possible in order to maintain maximum production capacity. Naturally, the post-treatment results in one or more rolls, which in turn must first be accelerated to full speed and then decelerated to a halt before they can be transferred to either the second post-treatment stage or to the 20 pack.

00 · ΜΦ · 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 at the rear, with the largest roll diameter. This is done either because of the mass of the reel, the mechanical drive, or the torque transfer of the socket seat, or to optimize the size of the electric drive. These techniques have traditionally used a simple limit approach, whereby the web roll diameter below a predetermined fixed limit value can be shifted to higher accelerations and decelerations. Essential to these techniques is the lack of on-line optimization or dynamic computation and / or limiting the dependence on diameter alone.

··· • · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Based on the "worst case" principle, that is, they are designed for maximum inertia, maximum line tension, maximum line speed, and with the winder, the most unfavorable torque difference between the rollers and the 5th maximum acceleration possible. In addition, the size or power ratings of the drives sometimes cause inevitable oversizing. Thus, since the electrical drive is dimensioned by assuming the maximum values of all the winding parameters to be required at any given time, the electrical drive capacity is underused most of the time.

It is also known technology to use acceleration and deceleration values for each paper type mainly dependent on its strength properties. Acceleration and deceleration of freely rotating rollers can also set limits on usable acceleration and deceleration values depending on the paper type.

From the prior art, it is also worth mentioning the method for controlling winding according to WO 2004/044665. Although the method discussed in the publication is relatively advanced, the disadvantage of the described speed limiting vibration damping method is that when used with the method. v 20 some capacity is lost.

• 1 · • · • 1 • · ·

*: 1 ·: (007) Further in US 4519039, US 2740078, DE 1021932 and JP

The solutions described in J,> #: 4138093 relate to utilization of the operating capacity reserve · 1 • 1 .. for fiber web winding, • · ·:: 25 ·· »(008) Thus, any prior art winding control method does not: V: be able to fully utilize the electrical drive capacity -: [[[:]. If the roll acceleration and deceleration values could be optimized according to the characteristics of each paper type, it would be possible to use lower values. 30 running speeds and still achieve lower production capacity. At the same time, process risks would also decrease. These process risks include: 3 119806 line breaks, resulting outages, and machine damage caused by outages, outages caused by line breaks, the length of which has been found to increase as a function of running speed, as well as 3 the amount of paper shred they produce increases as a function of running speed, operator-generated production disruption, and machine-generated production disruption.

It is an object of the present invention to reduce the number of web breaks and the duration of downtime resulting therefrom.

It is another object of the present invention to make maximum use of the capacity of the roller drives.

As a direct solution to at least some of the above problems and to at least some of the above objectives, it is proposed to use both the highest accelerations and decelerations and the lower speeds of rolling compared to the state of the art.

The present method achieves e.g. the following advantages: - the method can be utilized to increase the capacity of both the new delivery and the existing machine fleet,: [[[: 25 - the length of downtime caused by web breaks as a function of deceleration as faster stopping reduces the amount of paper shred: Y; restarts faster chair, in case of production disruption.

• t · ·. · * ·. In the method according to the invention, the acceleration and / or electrical power obtained during the processing of the unwound web roll during processing of the unwound web roll is utilized to dynamize the utilization capacity reserve of the fiber web. or deceleration capacity. The method is characterized in that the acceleration and / or deceleration of the electric drive is dynamically calculated or modeled during the production cycle and / or that the change in the acceleration and / or deceleration of the electric drive is predetermined.

It is a characteristic of the method according to another preferred embodiment of the invention that the inertia of the web roll to be accelerated or decelerated is taken into account in the calculation.

Other features of the process according to the invention will be apparent from the appended claims.

One exemplary use of the invention is a winder 15, in which paper or paperboard is unwound from a machine roll, cut into several sub-webs in its longitudinal direction and rolled into smaller rolls. Generally, in a web-winding application, two control systems are usually, but not necessarily, used. One controls the web winder itself and the other drives the electric drives. It is also possible to implement the web rewind application with a single control system: Y: 20 which controls both the web rewind machine and the electric drives.

··· • · • · • · *: ··; In the following, the method according to the invention for utilizing the capacity reserve for use in winding a fibrous web will be explained in more detail in the light of a preferred example.

In a method according to a preferred embodiment of the invention: Y: it is assumed that the web control system of the web winder is told what kind of web is being processed and what end products, i.e. web rolls, are required. In this case, the control system of the web rewind machine sends the necessary information, such as, ···. 30 for initial web speed, initial web tension, target web speed, target web speed, and winder roll torque difference, target torque difference, · · ·], and web density and web roll dimension information, electric drive control system. In some situations, some additional information may be required, and sometimes not all of the above may be required. With the information it receives, the electric drive control system determines the capabilities that the electric drive is capable of. In other words, the highest available / available values of unwinding acceleration 5 and rewinding acceleration in the case of incipient web rewinding, or respectively the highest available / available values of unwinding deceleration and rewinding deceleration in the case of end web rewinding. More specifically, the control system calculates the maximum acceleration or deceleration that each individual electric drive is capable of exerting on the roll or roll it is using. The electric drive control system can calculate eg. from roll diameter and web density data, for example, web roll inertia, whereby the known acceleration value of the roll unwound web can be used to calculate the maximum acceleration value that can be used to give a full web roll. Similarly, the control system is able to load the inertia of the web roll to be retracted, for example when braking begins, to determine the value of the maximum deceleration of the electric drive to the web roll. The electric drive control system transmits this information to the web winder control system, which compares them with the allowable values for the web being processed. In other words, if the maximum value given by the electric drive control system: Y: 20 for either the acceleration or deceleration of a roll is greater than the value allowed for the web to be processed, the control system: · 1: , based on which the electric drive control system controls the operation of each roller. If, in turn, the maximum values of electric drive are less than the allowable values for the web 25, the control system of the web winding machine accepts the values and informs the electric drive control system of these values as reference values. In this embodiment, the control system is designed to define a single value for each · ·: 2 acceleration or deceleration phase that is used throughout the acceleration or deceleration event. If the web rewinding machine Y1. If only one control system is controlled, the above procedure is performed in its entirety by · · Y by that control system.

119806 (0019) From the above embodiment, it is worth mentioning one particular case in which the web is driven from the machine roll to several successive web rolls. In this case, according to the above embodiment of the invention, the length of each length cutting cycle, i.e. the so-called. therefore, the maximum acceleration and deceleration values for both the machine roll and the web roll are already determined in the drive control system, which means the cut-off of one web roll, as described above. These winder control system compares the values allowed on the web and tells the drive control system to use the lower value in the comparison as a constant for both acceleration and deceleration of drives. The end result of this procedure is that the machine reel is driven with as many different acceleration and deceleration values as the machine reel produces successive web rolls, and that each web roll has its own acceleration and deceleration values that are different from the values of the acceleration and deceleration values are determinant 15 and not the limit values specific to the web material. Thus, by calculating the acceleration and deceleration values specific to each shift, the acceleration and / or deceleration capacities obtained during the driving cycle of each roll can be utilized: V: 20 The invention exemplified above has a number of possible variations. In a method according to another preferred embodiment of the invention, the control system of the web winder continuously or intermittently sends information on, for example, the roll diameters of the reel web and the reel web, which enables the electric drive control system to calculate new values the inertia of the rollers and, therewith, new values for the acceleration or deceleration of said rollers to which each roll: V: electric drive or brake generator is currently capable. When this information is supplied to the control system of the web winder, it in turn performs the comparison already described and gives the reference values to the operation control system. In other words, in this embodiment, both the unwinding e ·. * ·, * Machine rolls and the winding roll (s) are continuously or intermittently monitored. The advantage of this embodiment is that, if only the strength properties of the web yield up to the maximum acceleration or deceleration values, the maximum production capacity is also achieved. Thus, in this embodiment, the acceleration and / or deceleration capacity of the electric drive variable during the driving cycle of each roller is best utilized. Another embodiment of the invention is a method utilizing, for example, the reference values previously obtained in the manufacture of the corresponding product. In this case, these values may first be assigned to the web winding control system, which will forward them to the electric drive control system. Of course, in this 10 embodiment, either a control based on constant acceleration and deceleration, or continuously or periodically varying acceleration and deceleration values obtained by continuous or intermittent monitoring can be used. If the web winding machine is controlled by only one control system, the procedure described above will be performed in its entirety when the respective control system is maintained.

A third possibility provided by the invention is to make a computational model which estimates the change in inertia of the web rolls as a function of as many winding parameters as possible and uses it instead of the actual measurements: Y: 20.

··· • · • · * · *: **! The most preferred embodiments of the present invention are web winding machines in which one or more smaller rolls / rolls are formed from one roll. If the web winding machine is controlled by only one control system, the entire procedure described above is performed by that control system.

(0024) From the foregoing, it should be noted that the term ··· Y electric use is commonly used above. It refers to ac, DC or servo drives used to rotate rolls, reel, cutter blades and web rollers. Electric drives include electric motors, frequency converters and / or supply • · * · '· *' devices including supply groups and transformers. For the purposes of the foregoing, however, it is not appropriate to limit the term "electrical use" precisely. Similarly, in the above examples, a machine roll and a web roll are discussed. However, these must be understood to include not only rolls between the machine roll and web roll, but also rolls 5 between two machine rolls or between two web rolls. Thus, windings can take place from one machine roll to another, from a machine roll through a cutter to a plurality of sub rolls, and from one web roll to another web roll. This is the case, for example, with rewinding or rewinding when the rewinding or rewinding machine is stopped for hole insertion, connection or inspection.

10 «i • · * * · · · · · · · · ··························································································································· · · • 1 1 * · · • • • 1 · • · · · · · 1 1 • • · · · 1

»M

··· • · · · · 1 · * · § • ·· • 1

Claims (10)

A method of utilizing the operating capacity reserve in rolling a fiber web, in which the method of variable acceleration and / or deceleration capacity of the electric drive is utilized in the web rolling machine during the treatment of a web roller which is inclined to be unrolled, characterized in that the acceleration and / or deceleration capacity of the electric drive is calculated or modeled dynamically during the production cycle and / or that the change in the acceleration and / or deceleration capacity of the electric drive is predefined. 10 2. A method according to claim 1, characterized in that the inertia of the accelerated or decelerated web roll during roll-off is taken into account in the calculation. 15 Method according to any of the preceding claims, characterized in that the inertia (s) of the accelerated or decelerated web roll (s) in the up-roll is taken into account in the calculation. Method according to any of the preceding claims, characterized in that the web voltage used, and the torque difference between the rolling choice - the same on the roller cutting machine are taken into account in the calculation. • · ··· • ♦ .Γ * Method according to any of the preceding claims, characterized in that fixed or periodically varying acceleration and deceleration values are used during the acceleration and deceleration, which values have been defined before the beginning of the acceleration or deceleration. • · · • · • m •. Method according to any of the preceding claims, characterized by ... that the change of the inertia of the rollers is estimated and the estimate is used in the calculation instead of actual measurements. ·· • · ♦ • ♦ • · · • ·· • · 12 1 1 9806 Process according to any of the preceding claims, characterized in that paper-type-specific properties are taken into account when considering acceleration and deceleration values for the scroll. 5 Method according to any of the preceding claims, characterized in that the acceleration or deceleration values determined on the basis of paper type-specific driving parameters are compared in the determination of acceleration or deceleration values with the values received from the electric drive control system and the lower of these values are selected for the fire values. 10 Method according to any of the preceding claims, characterized in that the web roller is a machine roller. Method according to any one of the preceding claims, characterized in that the web roll is the web roll of the roll or intermediate roll. • «• * * • · · * ·» M • ♦ Φ · ΦΦΦ • • Φ • ΦΦ • · • · ··· ΦΦ φ Φ φ ΦΦ Φ φ # # Φ Φ • Φ (ti Φ · · Φ Φ · Φ # f Φ Φ Φ φ Φ Φ Φ IM Φ Φ m · Φ · φ φ φ Φ Φ ΦΦ φ «« Φ «« «« «Φ φ φ φ Φ * Φ