Patent Publication Number: US-2004046080-A1

Title: Method for changing a reel in a reel-up and a tape for use in the method

Description:
[0001] The invention relates to a method disclosed in the preambles of the appended independent claims for changing a reel in a reel-up of a paper or paperboard machine or finishing apparatus of paper or paperboard, especially in a continuous reel-up without reducing the running speed of the web, as well as to a tape used in the method.  
       [0002] In the reel-up of a paper machine, in a so-called pope reel-up or in a centre drive assisted pope reel-up, finished paper is reeled around a reeling core, such as a reel spool after the calender. The reeling itself is conducted in such a manner that the reeling core is loaded against the reeling cylinder via which the web to be reeled travels, winding around the reeling core and forming a complete reel.  
       [0003] This section of the paper machine should also function without interruptions and receive the continuous paper web coming from the preceding sections of the paper machine. Thus, when the old reel has become full, it is necessary to cut the web and start winding the web following the cutting point around a new reeling core. In practice, this takes place in such a manner that when the paper reel has become full, a new empty reeling core, i.e. for example a reel spool is transferred in contact with the paper web on the surface of the reeling cylinder, whereafter the paper web is cut by means of a suitable method and the end of the web following the cutting point is guided on the periphery of an empty reeling core, on which the new reel now starts to accumulate.  
       [0004] The most critical phases of the reeling are, in fact, the cutting of the paper web and the act of bringing the new end of the web around the empty reeling core. To avoid unnecessary broke, the change must take place without problems. In an ideal situation the new end of the web is brought immediately neatly against the peripheral surface of the empty core, such as the reel spool. It is well known that many methods are used for the cutting and change, depending on the basis weight of the web to be reeled.  
       [0005] A generally used change method is pocket change which is suitable for all grades, but which typically causes quite a large amount of bottom broke and may cause harmful impacts in the reel-up. Another method is a so-called gooseneck change in which the above-mentioned problems do not occur, but it is suitable only for thin grades. A third method is a tape change, and the present invention relates to a change method in accordance therewith. In the tape change the cutting of the web and guiding of the same onto a new reel are typically conducted by using a tape which is guided into the nip between the reeling core and the reeling cylinder in the vicinity of the ends of the reeling core and the reeling cylinder, whereafter the tape, as it winds spirally over the width of the reeling core, at the same time cuts the web diagonally and guides the new end following the cutting point of the web around the reeling core.  
       [0006] The devices used in tape change are disclosed for example in patent publication GB 1 135 945, U.S. Pat. No. 4,711,404 and Finnish published application 74679. In the devices disclosed in these publications the end of the tape that is equipped with an adhesive layer is pushed between the reel spool and the reeling cylinder by means of a suitable tool, and the tape adheres on the surface of the reel spool by means of glue.  
       [0007] At present, the speeds of paper machines are generally 20 m/s or higher, and the aim is, of course, to attain even higher speeds. The cutting of a rapidly travelling web is not a problem as such, and forces caused by the speed can even be utilized in the cutting. The critical point is to bring the end of the new web immediately against the peripheral surface of the reel spool, so that it follows the peripheral surface at high peripheral speed, and to prevent the uncontrolled wandering of the end of the web and incorrect positioning of the same on the reel spool. This problem becomes worse when the basis weight is increased.  
       [0008] Furthermore, unlike in reeling conducted by means of slitter winders, on a continuously operating reel-up the end of the web is not glued to the reeling core before reeling begins, as is the case in reeling conducted by means of slitter winders, because when using known methods the glueing would require that the machine is stopped. In slitter winders glueing is utilized, because when a disposable core is used as a winding core, it is possible that in the course of time slippage will occur between the bottom layers of the reel and the core. The above-mentioned slippage may result for example from changes in the humidity of air, whereby the diameter of the core becomes smaller faster than the diameter of the web wound thereon, wherein the bottom of the roll becomes slack. A slipping bottom impairs or even prevents the unwinding process of the roll, wherein the roll has to be rejected.  
       [0009] It is an aim of the method according to the present invention to eliminate or at least reduce the problems caused by the above-mentioned state of the art, and to present a method for changing a reel in a reel-up of a paper machine at full running speed and a tape used in the method, by means of which the new end of the reel is glued immediately. To attain this purpose among other things, the method and the tape according to the invention are primarily characterized in what will be presented in the characterizing parts of the appended independent claims.  
       [0010] Advantageously, in the method according to the invention, the adhesive agent in the tape is brought to a state that activates the adhesive agent at the moment of reel change or thereafter. In this context the term adhesive agent refers to an agent that can be activated to an adherent state and that is located on both surfaces of the tape as a sectional or continuous adhesion surface.  
       [0011] According to a preferred embodiment of the invention, the activation of the adhesion surfaces is conducted by means of a compressive pressure between the reeling core and the reeling cylinder. According to one embodiment at least part of the adhesion surfaces of the tape is activated by means of radiation exerted on the tape, such as heat radiation or UV radiation. Furthermore, according to one embodiment at least part of the adhesion surfaces of the tape are activated by means of moisture exerted on the tape. The activation of the adhesion surfaces can also be conducted by means of another chemical or physical phenomenon. The way in which the adhesion surfaces are activated is determined according to the properties of the adhesive agent that is being used.  
       [0012] When the adhesive agent on the tape is activated only at the moment of reel change, the handling and transfer of the tape to the nip becomes easier, because the adhesive agent is dry and resistant to the handling. The adhesive agent is not activated for example when the tape is coiled up, but only in set, precisely determined conditions.  
       [0013] In a preferred method according to the invention a tape is used, both sides of which are at least partly treated with an adhesive agent, such as glue or adhesive tape, which is activated i.e. becomes adherent only after an activation exerted on the tape. The adhesive agent on both sides of the tape glues the bottom layers of the web reeled on a reeling core against each other, wherein the bottom of the reel becomes tight.  
       [0014] In the tape according to the invention both sides of the tape are at least partly treated with an adhesive agent that is activatable to an adherent state as a result of activation exerted on the tape.  
       [0015] According to a preferred embodiment of the invention, the adhesive agent consists of pressure-sensitive glue or adhesive tape, which is activated when the pressure exerted on the adhesive agent exceeds a threshold pressure of the adhesive agent. In an advantageous embodiment, the threshold pressure of the adhesive agent is over 1 Mpa.  
       [0016] According to second embodiment of the invention, the adhesive agent is sensitive to heat radiation or UV radiation exerted thereon. According to a third embodiment of the invention, the adhesive agent is sensitive to moisture exerted thereon.  
       [0017] According to a preferred embodiment of the invention, the adhesive agent on the surface of the tape has an activation delay that determines the time passed from the activating action to the activation of the adhesive agent. As a result of the activation delay, the tape is not glued on the surface of the reeling cylinder, but the adhering effect only begins inside the reel.  
       [0018] In an embodiment according to the invention, the activation delay is typically at least 0.01 seconds, and advantageously 0.01 to 0.25 seconds. 
     
    
    
     [0019] In the following, the invention will be described in more detail with reference to the appended drawing, in which  
     [0020]FIG. 1 shows a reel-up of a paper or paperboard machine in which the method and tape according to the invention are used,  
     [0021]FIG. 2 shows a part of the longitudinal cross-section of the tape according to the invention, and  
     [0022]FIG. 3 illustrates the activation of the tape and a preferred structure of the reeling core. 
    
    
     [0023]FIG. 1 shows schematically a reel-up of a paper machine, which is based on a so-called pope reel-up. The reel-up continuously forms paper reels from a full-width web W coming from a paper machine or finishing apparatus for paper, of which paper reels one that has become full is marked with the letter R in the drawing. The reel-up shown in the drawing comprises a reeling cylinder  2  rotating in a support  1 . The web W winds via the reeling cylinder around the actual reel R. Above the reeling cylinder there is a reel spool functioning as a reeling core  3  for the new paper reel. The reel-up also comprises a conveying profile  4  for guiding the tape  5  used in the cutting of the web into the space between the reeling cylinder  2  and the above-mentioned reeling core  3 . In the drawing, this space is marked with the reference numeral  6 . The reel-up is advantageously centre drive assisted, in other words in addition to the reeling cylinder, the reeling core  3  is also equipped with a drive (not shown). The change is conducted at the running speed.  
     [0024] The tape  5  is fed along the conveying profile  4  with a feeding mechanism  7 , which typically contains a feeding device that rations the tape from a storage reel to the conveying profile  4 , and a cutter of the tape that cuts the tape  5  into the right length after the web has been cut. The above-mentioned devices belong to prior art, and therefore they are not described in more detail.  
     [0025]FIG. 2 schematically shows the structure of the tape  5  according to the invention. On both surfaces of the core  8  of the tape there are adhesion surfaces  9 , which have been produced by treating the core  8  with a pressure-sensitive glue used as an adhesive agent, which is activated i.e. becomes adherent only after a predetermined threshold pressure is exceeded. The adhesion surfaces  9  may be continuous over the entire length of the tape, or there may be sectional adhesion surfaces  9  on the surface of the tape.  
     [0026] In the method according to the invention, the above-described reel-up is used in the following manner: When preparations are being made for the cutting of the web W, a suitable amount of tape  5  is fed along the conveying profile  4  by means of the feeding mechanism  7  to the space between the reeling cylinder  2  and the reeling core  3  which is open at this stage, i.e. to the nip  6  in the vicinity of the end of the reeling core. To fasten the end of the tape on the surface of the reeling core  3  outside the web, there may be a device at the final end of the conveying profile that spreads an instantly adherent glue on the end of the tape, as disclosed for example in the publication U.S. Pat. No. 4,711,404. Alternatively, a piece of adherent material may be arranged at the end of the tape  5 , said material being capable of engaging mechanically with the end of the reeling core  3 , and for this purpose, the end of the reeling core  3  can comprise a special zone of the adherent material, with which the piece of adherent material arranged at the end of the tape  5  can engage in the manner shown in the publication EP 350133. The cutting of the web begins in such a manner that the reeling core  3  that previously has been accelerated to the peripheral speed (for example by means of a drive located in a primary reeling device  10 ) corresponding to that of the reeling cylinder  2  are lowered down in contact with the web W on top of the reeling cylinder  2 , at which moment the nip  6  is closed. The devices for accelerating and guiding the reeling core are generally known, and therefore they are not described in more detail herein.  
     [0027] When the nip  6  is closed, the end of the tape  5  remains between the reeling core  3  and the reeling cylinder  2 , and the end of the tape  5  adheres to the surface of the reeling core  3 . As a result of the rotating movement of the reeling core, the tape  5  is wound around this reeling core and tightens, wherein it, starting at its free end, disengages from the conveying profile  4  and tightens between the nip  6  and the feeding mechanism  7 , cutting the web W in two by a stroke, winds spirally over the width of the reeling core, and guides the end of the web following the cutting point to the reeling core  3 . During the above-described stages the tape travels through the nip  6 . Subsequent layers of the new reel are positioned on top of the tape around the core  3 .  
     [0028] At the same time when the tape  5  travels through the nip  6 , the pressure sensitive glue contained in the adhesion surfaces and used as the adhesive agent is activated and it glues the bottom layers formed of the web W on the reel to each other, wherein the bottom becomes tight. The production of the activation pressure is enhanced by the fact that the pressure exerted on the tape itself in the nip is higher than the average pressure produced in the linear load of the nip as a result of the increased thickness caused by the tape. The delay in the activation of the glue is such that the tape  5  is not glued on the surface of the reeling cylinder  2 , but the adhering effect only begins inside the reel that is being produced, when the tape is already covered by the paper placed on top of the core.  
     [0029] The purpose is not to restrict the invention solely to the embodiment described above, but it can be modified within the scope of the inventive idea presented by the claims. The adhesion surfaces  9  of the tape according to the invention can also be produced by means of a substance other than glue, such as adhesive tape, or the like. The adhesion surfaces  9  can also be made of a material that can be activated in some other way. The substance used as an adhesion surface can also be activated by means of heat radiation or UV radiation or moisture, or by means of another chemical or physical phenomenon exerted thereon. In this case, the reel-up used in the method comprises the necessary auxiliary parts such as for example moisteners and heat radiators for the activation of the tape. Such a moistener, radiator or another activation device can be arranged for example in the primary reeling device  10  supporting the ends of the reeling core in the change position, and the activation process can be synchronized precisely in accordance with the moment of change. The tape  5  can also comprise other surfaces than the ones mentioned above, and it can also be produced in such a manner that the core  8  is made of a material that can be activated, wherein a surface to be added on top of the core  8  is not necessary.  
     [0030]FIG. 3 shows a side view of a situation in which the tape  5  is wound around the reeling core  3 . The device that exerts an activating process on the tape  5  in a contactless manner is marked with the reference numeral  11 . The device  11  is directed towards the surface of the reeling core  3  in such a manner that is exerts for example a water jet, UV radiation or heat radiation on the tape. It is possible that the process is capable of affecting the tape even if the tape were already covered by the paper coming to the new reel. By means of these ways of activation, the adhesive agent on the tape can also be activated within a fixed delay, but this is not necessary, if the tape can no longer enter in direct contact with the reeling cylinder  2  after the activating process. In the drawing, the reeling core  3  consists of two parts. The inner part  3   a  of the same consists of a reel spool that is utilized in reel-ups and that can be used several times, the end of which is equipped with a connecting element to couple the same to an external drive motor to rotate the reel spool and the reel. The outer part of the reeling core, i.e. the surface layer  3   b , is composed of a sleeve that is fitted around the reel spool, which, being disposable, can be drawn out of the reel spool and replaced by pushing a new sleeve in its place. This sleeve can be made of paperboard, for example. Thus, the invention is especially well suited to cases in which the reeling core  3  contains a disposable surface layer  3   b  according to FIG. 3, but, in principle, it can be applied in all reeling cores around which paper or paperboard web is accumulated to form a reel.  
     [0031] Furthermore, in the description hereinabove, less attention is paid to other accessory devices of the terminal end of a paper or paperboard machine, such as the transfer devices of the full reel and the transfer devices of the new reeling core, because these devices are accessory devices independent of the invention, and solutions generally known in the field can be used as such devices.