Patent Application
20240217767
This application claims priority on FI 20235009, filed Jan. 4, 2023, the disclosure of which is incorporated by reference herein.
Not applicable.
In general, the present invention relates to production of fiber webs, in particular to producing of thick fiber webs such as pulp webs. More especially the present invention relates to slitter-winders configured to unwind, slit and wind a thick fiber web to customer rolls and a method for slitting and winding a fiber web.
As known, fiber webs, also thick fiber webs, are manufactured in machines together forming a fiber web manufacturing line, which may be hundreds of meters long. Fiber webs, especially paper and board are available in a wide variety of types and can be divided according to basis weight in two grades: papers with a single ply and a basis weight of 25-300 g/m2 and boards manufactured in one- or multi-ply technology and having a basis weight of 150-600 g/m2. It should be noted that the borderline between paper and board is flexible since board grades with lightest basis weights are lighter than the heaviest paper grades. Generally speaking, paper is used for printing and board for packaging. Thick fiber webs are generally considered to comprise pulp webs and thick board webs. The density of a pulp web is about 400-800 kg/m3 and the thickness of the pulp web is about 0.5-2.5 mm. Thick board webs typically have a thickness of at least 0.3 mm.
In fiber web production lines, manufacturing operates as a continuous process. The finished fiber web being output from the fiber web production line is wound with a reel-up around a reeling shaft, i.e. a reel spool, into a parent roll (a machine roll). The purpose of the reeling is to transfer the fiber web from its planar manufacturing form into a form in which it can be handled more easily. The reel-up is thus a device that reels a material, which is produced as a continuous fiber web in a fiber web production line, into the form of a roll; the parent roll. In the production process of the fiber web, the reeling is generally a first process part, wherein a continuous process is discontinued to be continued in sequences. The parent roll is formed around the reeling shaft that functions as a core of reeling, i.e. the fiber web on one parent roll around one reeling shaft has a beginning end and an end.
The fiber web of the parent roll generated during manufacture is full-width and long, so it must be slit and cut into partial webs of a suitable width and length for customers and wound around cores into “customer rolls” before dispatch to customers. As known, this slitting and winding of the web takes place in a separate machine fitted to the purpose, i.e., in a slitter-winder, which comprises an unwinding section, a slitting section and a winding section. In the slitter-winder the parent roll is unwound in an unwinding station of the unwinding section off the reeling shaft and the fiber web is slit with slitting blades of the slitting section into a number of narrower partial webs, which are wound in a winder of the winding section around winding spools such as cores into the customer rolls. When the customer rolls are ready, the slitter-winder is stopped and the rolls, or “set”, is removed from the machine. After this, the process continues with the winding of a new set. These stages are repeated periodically. In cases where the unwinding section comprises only one unwinder, the stages are repeated until the fiber web on the parent roll runs out from the reeling shaft, at which point the parent roll is replaced, the end of the fiber web from the emptying parent roll is joined to the beginning end of the fiber web from a new parent roll, emptying and the operation restarts with the unwinding of a new parent roll from the reeling shaft. In unwinders of slitter-winders for thick fiber webs the parent roll change in the unwinder is typically slow due to challenges caused by the thick fiber web. Typically it takes even ten minutes.
The joining of the end of the parent roll to the beginning end of the next parent roll creates a joint to the fiber web to be further processed in the slitter-winder to the customer rolls. In connection with thick fiber webs it has been difficult to find a functional joining method. For example, using adhesive tapes has proven disadvantageous, as the tapes may peel off fibers from the surface of the thick fiber webs. At the present the most promising joining method has turned out to be a form fitting joint. But these joints are thicker than the rest of the fiber web and thus, these joints are not welcome in the customer rolls as they may cause problems in the end processing of the thick fiber web obtained from the customer rolls to end products at customer sites. It is known from the prior art to run the slitting and winding process such that the joint is located in the bottom layers of the customer roll, but this has caused vibration problems in further processing of the customer rolls. It is also known from the prior art to run the slitting and winding process such that the joint is located on the outer layer of the customer roll, but this has proven difficult as the process is fast and there is not time to manually remove the joint.
The slitting and winding process is a cyclic process, wherein the process is in the beginning accelerated to a set running speed and when a set of customer rolls is about to be finished the process is decelerated to be stopped for the set change. The finished set of the customer rolls is removed from the winder of the slitter-winder and new cores for winding the next set of the customer rolls are fed to the winder. Thus, the capacity of a slitter-winder is dependent on the sequence times of the slitter-winder, especially on the stopping time, and on the running speed of the slitter-winder.
Slitter-winders employ winding devices of different types, for example multi-station winders and two-drum winders. In the two-drum winders the partial webs are wound around winding cores supported by two winding drums to partial web rolls via a nip between the winding drums and the partial pulp web rolls being formed. In the two-drum winders also a belt arrangement i.e., a so-called set of belt rolls with a belt loop or belt loops located around two guide rolls can be used as the winding drum. As known in the prior art, winding with a shaft without cores or together with cores can also be employed in the winding of a pulp web into customer rolls on a slitter-winder.
An object of the invention is to create a slitter-winder for thick fiber webs and a method for slitting and winding a thick fiber web, in which the disadvantages and problems of the prior art are eliminated or at least minimized.
An object of the invention is to create a slitter-winder for thick fiber webs and a method for slitting and winding a thick fiber web, in which the problems relating to the long parent roll changes are eliminated or at least minimized.
An object of the invention is to create a slitter-winder for thick fiber webs and a method for slitting and winding a thick fiber web, in which the problems relating to the joints are eliminated or at least minimized.
In this description and in the claims by the term “thick fiber web” is meant a fiber web that has a basis weight of at least 200 g/m2. The present invention relates to production of thick fiber webs and it is especially suitable in connection with the production of pulp webs, as well as thick board webs, such as folding boxboards and liquid packaging boards. The winding drum can also be a belt arrangement i.e., a so-called set of belt rolls with a belt loop or belt loops located around two guide rolls.
According to the invention the slitter-winder for fiber webs comprises an unwinding section, a slitting section and a winding section, and the slitter-winder is configured to unwind, slit and wind a thick fiber web to customer rolls, the thick fiber web having a basic weight of at least 200 g/m2, the unwinding section of the slitter-winder comprises a first unwinder and a second unwinder for unwinding the thick fiber web from a parent roll comprising full-width thick fiber web, and a joining device for joining a beginning end of a thick fiber web coming from a parent roll in the first unwinder to an end of a thick fiber web coming from a parent roll in the second unwinder by forming a joint, and the winding section of the slitter-winder comprises a cutting device for cutting and removing part(s) of the thick fiber web comprising the joint from the winding section.
According to an advantageous feature of the invention in the slitter-winder the slitting section of the slitter-winder comprises slitting blades for slitting the full-width thick fiber web in the longitudinal direction of the thick fiber web to partial thick fiber webs, the winding section of the slitter-winder comprises at least one winding drum for winding the partial thick fiber webs to customer rolls, and the winding section of the slitter-winder has a cutting device for cutting the partial thick fiber webs when a set of the customer rolls is finished and the cutting device is also configured to cut the partial thick fiber webs when a set of the customer rolls is finished.
According to an advantageous feature of the invention the slitting section of the slitter-winder comprises slitting blades for slitting the full-width thick fiber web in the longitudinal direction of the thick fiber web to partial thick fiber webs, the winding section of the slitter-winder comprises at least one winding drum for winding the partial thick fiber webs to customer rolls and the slitting section comprises an additional cutting device configured to cut the partial thick fiber webs when a set of the customer rolls is finished.
According to an advantageous feature of the invention, the slitter-winder comprises a reject handling system configured to receive the cut part(s) comprising the joint removed from the thick fiber webs.
According to an advantageous feature of the invention, the winding section comprises a two drum winder comprising a front winding drum and a back winding drum and that the cutting device is located between the front winding drum and the back winding drum.
According to an advantageous feature of the invention the winding section comprises a two drum winder comprising a front winding drum and a back winding drum and that the cutting device is located below the front winding drum and the back winding drum.
According to an advantageous feature of the invention the winding section comprises a two drum winder comprising a front winding drum and a back winding drum and that the cutting device is located in front of the front winding drum.
According to an advantageous feature of the invention the joining device is configured to form a form-fitting joint.
According to the invention in the method of slitting and winding a fiber web in a slitter-winder comprising an unwinding section, a slitting section and a winding section, a full-width thick fiber web is unwound in the unwinding section, the thick fiber web has basic weight of at least 200 g/m2, in the method the full-width thick fiber web is alternatingly unwound in the unwinding section from a parent roll in a first unwinder and from a parent roll in a second unwinder, in the method a beginning end of a thick fiber web coming from the parent roll in the first unwinder to an end of a thick fiber web coming from the parent roll in the second unwinder by a joining device forming a joint between the beginning end and the end, and in the method part(s) comprising the joint are cut by the cutting device and removed from the winding section automatically.
According to an advantageous feature of the invention in the method the fiber web is slit in the longitudinal direction of the thick fiber web to partial thick fiber webs and the partial thick fiber webs are wound to customer rolls in the winding section, which comprises at least one winding drum and in the method the partial thick fiber webs are cut by the cutting device or by an additional cutting device, when a set of the customer rolls is finished.
According to an advantageous feature of the invention in the method the part(s) of the thick fiber web with the joint is/are guided through the winding section towards a reject handling system.
According to an advantageous feature of the invention the part(s) comprising the joint is/are cut by the cutting device and removed from the thick fiber web of the partial thick fiber webs to the reject handling system through a reject opening or by a reject conveyor.
According to an advantageous feature of the invention, in the method the part(s) of the thick fiber web of the partial thick fiber webs with the joint is/are guided through the winding section over the at least one winding drum.
According to an advantageous feature of the invention the method comprises stages of a) finishing winding of a finished customer roll set and removing the finished customer roll set from the winder, b) changing the unwinding from emptying the parent roll in one unwinder to a new parent roll in the other unwinder and joining the fiber web ends, c) preparing the winder for the next customer roll set winding, and d) beginning steps for the winding of the new customer rolls step.
According to an advantageous feature of the invention in the method stages a) finishing winding of a finished customer roll set and removing the finished customer roll set from the winder and b) changing the unwinding from the emptying parent roll in one unwinder to a new parent roll in the other unwinder and joining the fiber web ends are performed simultaneously.
According to an advantageous feature of the invention in the method before stage a) finishing winding of a finished customer roll set and removing the finished customer roll set from the winder the slitter-winder is decelerated to crawling speed or to a stop.
According to an advantageous feature of the invention in the method after the stage d) beginning steps for the winding of the new customer rolls step the slitter-winder is accelerated to a running speed.
According to an advantageous feature of the invention in the method, the fiber web is jogged, i.e., run at a lower (crawling) speed than the running speed, forward between the cutting for finishing the customer rolls and the cutting of the part(s) of the thick fiber web comprising the joint for removing the part(s) of the thick fiber web comprising the joint.
According to an advantageous aspect of the invention in the slitter-winder for thick fiber webs and in the method of slitting and winding a thick fiber web, in the unwinding section has two unwinders in order to make the supply of the thick fiber web for the slitting and the winding last longer and to decrease the capacity loss of the stopping times. When a parent roll unwound on a first unwinder is almost empty, the end of the fiber web coming from the parent roll on the first unwinder is joined to the beginning end of the fiber web coming from a parent roll on a second unwinder by a joining device based on a form-fitting joint creating technique. The unwinding is changed to the second unwinder and a new parent roll is moved to the first unwinder. When the parent roll unwound on the second unwinder is almost empty, the end of the fiber web coming from the parent roll on the second unwinder is joined to the beginning end of the fiber web coming from the new parent roll on the first unwinder. These stages are repeated until the required customer rolls have been produced.
According to an advantageous aspect of the invention in the method the joining of the fiber web ends in the unwinding section and the set change in the winding section are performed at least partially simultaneously.
According to an advantageous aspect of the invention the joint is removed from the thick fiber web in the winding section of the slitter-winder before the beginning ends of the slitted partial fiber webs are guided to be wound to the customer rolls. Thus, the joints are not present in the finished customer rolls.
According to an advantageous aspect of the invention in the method the joint is guided via the winding section towards a pulper or other reject handling of the fiber web production line and thereafter the thick fiber web is cut such that the part of the thick fiber web with the joint is guided to the pulper or the reject handling and the new end of the thick fiber is guided to winding of the customer rolls.
According to an advantageous aspect of the invention as the cutting device cutting the part of the thick fiber web with the joint is utilized the cutting device of the slitter-winder is used for cutting the partial fiber webs. Advantageously, a blowing device may be utilized for helping guidance of the part of the thick fiber web with the joint.
According to an advantageous aspect of the invention in the method the set change is interrupted after the customer rolls have been removed from the winder before the cores for the next customer roll set winding are placed in the slitter-winder. Advantageously, the cores for the next customer roll set winding are placed in the slitter-winder after the part of the thick fiber web with the joint has been removed.
By the invention and its advantageous features many advantages are achieved: The change time of the parent roll in the unwinding section is reduced to less than two minutes, which improves the capacity of the slitter-winder for thick fiber webs significantly, even 30-40%. This also provides the possibility of using higher running speed at a board machine or at a pulp dryer. Additionally, the customer rolls are provided to the customers without joints, which improves the production of the end products at the customer site. One of the main advantages is also that no manual removal of joints is needed. Further, stability of winding of the customer rolls in the winding section is improved in cases where form-fitting joints are used, as the joints do not function as an impulse for possible vibration.
In the following the invention is explained in detail with reference to the accompanying drawings to which the invention is not to be narrowly limited.
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During the course of the following description, like numbers and signs will be used to identify like elements according to the different views which illustrate the invention and its advantageous examples. In the figures some repetitive reference signs have been omitted for clarity.
In the examples of the figures is schematically shown a slitter-winder for fiber webs, which comprises an unwinding section 10, a slitting section 20 and a winding section 30. The slitter-winder is configured to unwind, slit and wind a thick fiber web having a basic weight of at least 200 g/m2 to customer rolls 33. The unwinding section 10 of the slitter-winder comprises two unwinders: a first unwinder 11 and a second unwinder 12 for unwinding the thick fiber web from a parent roll comprising a full-width thick fiber web W11, W12. The unwinding section 10 further comprises a joining device 16, 17 for joining a beginning end of a thick fiber web W11 coming from a parent roll in the first unwinder to an end of a thick fiber web W12 coming from a parent roll in the second unwinder by forming a joint J. The winding section 30 of the slitter-winder has a cutting device 35 for cutting and removing part(s) of the thick fiber web comprising the joint J from the winding section 20.
The slitting section 20 of the slitter-winder comprises slitting blades 21, 22 for slitting the full-width thick fiber web W11; W12 in the longitudinal direction of the thick fiber web to partial thick fiber webs W20. The winding section 30 of the slitter-winder comprises at least one winding drum 31; 32 for winding the partial thick fiber webs W20 to customer rolls 33 and the cutting device 35 is also configured to cut the partial thick fiber webs when a set of the customer rolls 33 is finished or the slitting section 20 comprises an additional cutting device configured to cut the partial thick fiber webs when a set of the customer rolls 33 is finished. The cutting device 35 is a full width cutting blade or a traversing fixed or rotating blade. The cutting device 35 may also be a scoring device for weakening the thick fiber web at the cutting location and the actual cutting is provided by tension, blowing or as such by one skilled in the art known manner.
The slitter-winder comprises a reject handling system configured to receive the cut part(s) comprising the joint J removed from the thick fiber web or from the partial thick fiber webs W. The joining device 16,17 is advantageously configured to form a form-fitting joint J. In the method of slitting and winding a fiber web in a slitter-winder according to the examples of the figures a full-width thick fiber web W11, W12 is unwound is the unwinding section 10, and the full-width thick fiber web W11, W12 is alternatingly unwound in the unwinding section 10 from a parent roll in a first unwinder 11 and from a parent roll in a second unwinder 12. In the method a beginning end of a thick fiber web W11 coming from the parent roll in the first unwinder to an end of a thick fiber web W12 coming from the parent roll in the second unwinder by a joining device 16, 17 forming a joint J between the beginning end and the end. In the method part(s) of the thick fiber web comprising the joint J are cut by the cutting device 35 and removed from the winding section 30 automatically. In the method the part(s) of the thick fiber web comprising the joint J is/are guided through the winding section 30 towards a reject handling system over the at least one winding drum 31; 32, as the part(s) comprising the joint J is/are cut by the cutting device 35 and removed from the thick fiber web or the partial thick fiber webs W to the reject handling system through the reject opening 45 or by the reject conveyor. Thus, the method comprises the stages of a) finishing winding of a finished customer roll set and removing the finished customer roll set from the winder, b) changing the unwinding from emptying parent roll in one unwinder to a new parent roll in the other unwinder and joining the fiber web ends, c) preparing the winder for the next customer roll set winding, and d) beginning steps for the winding of the new customer rolls. In the method stages a) finishing winding of a finished customer roll set and removing the finished customer roll set from the winder and b) changing the unwinding from the emptying parent roll in one unwinder to a new parent roll in the other unwinder and joining the fiber web ends are performed simultaneously. In the method before stage a) finishing winding of a finished customer roll set and removing the finished customer roll set from the winder the slitter-winder is decelerated to crawling speed or to a stop. In the method after the stage d) beginning steps for the winding of the new customer rolls step the slitter-winder is accelerated to a running speed.
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In the method the fiber web is jogged, i.e. run at a lower (crawling) speed than the running speed, forward between the cutting for finishing the customer rolls and the cutting of the part(s) of the thick fiber web comprising the joint for removing the part(s) of the thick fiber web comprising the joint.
In the description in the foregoing, although some functions have been described with reference to certain features and examples, those functions may be performable by other features and examples whether described or not. Although features have been described with reference to the certain examples, those features may also be present in other examples whether described or not.
Above only some advantageous examples of the inventions have been described to which examples the invention is not to be narrowly limited and many modifications and alterations are possible within the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20235009 | Jan 2023 | FI | national |
