WO2009090296A1

WO2009090296A1 - A method and an apparatus for removing a glue protection at a joint in a paper reel

Info

Publication number: WO2009090296A1
Application number: PCT/FI2009/000006
Authority: WO
Inventors: Veli-Pekka Johansson
Original assignee: Veli-Pekka Johansson
Priority date: 2008-01-11
Filing date: 2009-01-09
Publication date: 2009-07-23
Also published as: FI121462B; FI20080022A0

Abstract

The invention relates to a method for removing a glue protection (31) at a splicing point (30) on a paper reel (4a, 4b), in which method the glue protections (30) attached onto a glue or tape at a splicing point (31) on a paper reel (4a, 4b) mounted on a reel exchange device (1) in a printing or paper machine or a corresponding machine for processing a paper web are removed by means of compressed air. In the method according to the invention, the glue protections (30) of the paper reel (4a, 4b) are removed by blowing compressed air to the glue protections (30) by at least one pneumatic nozzle (15) oriented primarily in the forward direction in relation to the direction of rotation of the paper reel (4a, 4b). The invention also relates to an apparatus according to the method of the invention.

Description

A METHOD AND AN APPARATUS FOR REMOVING A GLUE PROTECTION AT A JOINT IN A PAPER REEL

The invention relates to a method according to the preamble of claim 1 and an apparatus according to the preamble of claim 5.

In processes where web-like paper stored on reels is used as raw material, for example in printing and paper machines, a paper reel is changed by connecting the end of a new paper reel to the tail of the reel that is coming to an end, and by cutting the paper web of the reel that is coming to an end immediately after making the joint or splice. The joining is normally performed so that when a reel change is approaching, the rotating of a new reel is started. When the moment of change is approaching, the surface speed of the new reel is adjusted to the surface speed of the old reel as accurately as possible. When the reel that is coming to an end has reached its residual diameter and the end of the new reel is in a suitable position in relation to the old paper web, the new and old paper webs are pressed against each other. Immediately after the adhesion of the paper webs to each other, the paper web unwound from the old paper reel is cut off. For attaching the paper webs to each other, either double-sided tape or glue is most commonly used. The splicing point on the surface of the outermost revolution of the paper web on the new paper reel is usually prepared several minutes before the reel change. For this reason, the glue must remain tacky for at least this time. On the other hand, the glue must be such that a sufficient splice strength is achieved as a result of even a brief compression of the paper webs.

During the reel change, the new reel is rotated either by rotating a shaft in a spindle or by means of drive belts or pulleys in contact with the surface of the reel. If the new reel is rotated by means of drive belts or pulleys, the glueing point is protected so that no glue will adhere to the drive belt or pulley that rotates the reel. The protection is provided by means of a protection that covers the glue substance in part or in whole, or by making the glue less tacky at said point. As a totally covering protection, it is possible to use, for example, a release paper on double-sided tape. With a partly covering protection (for example perforated paper) implemented by making the glue less tacky at the point of contact with the drive belt or pulley, it is often not possible to achieve a splice of uniform quality between the new and old paper webs, or in the worst case, the reel change becomes a total failure. A splice of poor quality will cause creases and irregularities in the paper web, which may cause problems and malfunctions in the later steps of the process. Totally failed splicing of paper webs will, in turn, stop the whole process.

It is an aim of the invention to provide a method for eliminating the above- mentioned problems relating to the methods of prior art for protecting a glue splice in paper reels. In particular, the aim of the invention is to provide a method for preventing the failure of a reel change and for improving the quality of splices as well as for reducing the problems caused by splices of poor quality in process steps after the splicing. Yet another aim of the invention is to present an apparatus according to the method of the invention.

The aim of the invention is achieved by a method characterized in what will be presented in the characterizing part of claim 1 , and an apparatus characterized in what will be presented in the characterizing part of claim 5.

In the method according to the invention, the glue protections of a paper reel are removed by blowing compressed air to the glue protections by at least one pneumatic nozzle oriented primarily in the forward direction in relation to the direction of rotation of the paper reel. Such a method facilitates a successful reel change and enables higher running speeds than before during the reel change. Furthermore, thanks to the removal of glue protection by such a method, it is possible to use a glue splice of uniform quality, extending over the whole width of the web, at splices of the paper web, as well as glues which are stronger and dry faster than before, if necessary. Thanks to such a method, it is also not necessary to use perforated protective films or less tacky glue at the locations of the drive belts or pulleys rotating the paper reel, because the method makes it possible to use proper glue protections to cover the whole area to be glued. Thanks to better glue substances than before, and the glue joint extending homogeneously over the whole width of the web, the splices of paper webs will be of more uniform quality than before. As a result, failures in reel changes are reduced, and splices of the new and old paper reels become smoother and less creased, wherein problems caused by uneven splices are reduced/eliminated in later steps of the manufacturing process. It should also be noted that this kind of a method could also be applied in such reel exchange devices, in which glue protections are currently not in use, because the paper reel is rotated by rotating the shaft in a spindle. If the method of the invention were applied in such reel exchange devices, the reliability of the reel change could be improved in production lines, because thanks to the use of the glue protection, a glue that cures significantly faster and adheres better than before could be used at splices of paper webs.

The apparatus according to the invention comprises at least one pneumatic nozzle oriented primarily in the forward direction in relation to the direction of rotation of the paper reel, for blowing compressed air to the glue protection in the forward direction in relation to the direction of rotation of the paper reel. Such an apparatus is relatively small in size, and it can be implemented easily so that no modifications need to be made in existing reel exchange devices. Furthermore, as the compressed air required by it, in most cases it is possible to use compressed air supplied from the pneumatic system of the factory, wherein no separate air compressors will be needed.

In the following, the invention will be described in more detail with reference to the appended drawings, in which

Figure 1 shows a principle view of a reel exchange device at the initial end of a gravure printing press and an apparatus for removing a glue protection from a paper reel, and

Figure 2 shows a paper reel used in the gravure printing press according to Fig. 1 , as well as glue protections and a position indicator attached to its outer surface.

The reel exchange device 1 of the gravure printing press shown in Fig. 1 comprises a pivoting frame 2 that can be pivoted clockwise, seen in the direction of Fig. 1 , in a reel change situation, and spindles 3a and 3b installed at both ends of its pivot arms, on which spindles the paper reels used as raw material storage for said printing machine are mounted in turns during the operation of the printing machine so that printed products can be manufactured without interruption. Between the reel changes, the paper reel 4b in use is on the upper spindle and the used paper reel (Fig. 1 only shows the new reel and the reel coming to an end) on the lower spindle. When the change is approaching, the user paper reel on the lower spindle is replaced with a new paper reel 4a. Just before the change of paper supply, the pivot arms are turned 180° clockwise, wherein the new paper reel 4a pivots up and the old paper reel, which is still in use at this stage, pivots down (the situation shown in Fig. 1). When the old paper reel 4b comes to an end (when the reel achieves a so-called residual diameter), the supply of paper is changed to take place from the upper, new paper reel 4a. During the splicing and the normal paper supply after that, the upper reel 4a is rotated by a reel rotating device 5 separate from the spindle. In this case, it is belt-driven; in other words, the paper reel 4a is rotated by means of drive belts 6 to be turned against the outer surface of the paper reel 4a. In this case, there are four drive belts 6. The drive belts 6 are installed in pairs in two separate drive belt frames 7 which are tumable farther away from and closer to the upper spindle 3a. Thus, the drive belt frames 7 can be turned so that the drive belts 6 are completely off the outer surface of the paper reel 4a and so that the drive belts 6 are in contact with the surface of the paper reel 4a approximately in the way shown in Fig. 1. Furthermore, during the supply of the paper web, the drive belt frames 7 of the reel rotating device 5 move towards the spindle 3a in synchronization with the change in the diameter. The splicing of the old 4 and the new paper web is performed by a bonding roll 10 installed in a bonding (carriage 9 placed underneath the upper spindle 3a, which glueing roll is used for pressing the paper web 8 unwound at this stage from the lower paper reel against the outer surface of the upper new paper reel 4a. Before this operation, the new paper reel 4a is accelerated by the reel rotating device 5 to the same peripheral speed as the running speed of the paper web 8 unwound from the old paper reel 4b.

For determining the moment of turning the bonding carriage 9 and the position of the splice 31 on the surface of the new paper reel 4a, the reel exchange device 1 comprises a position sensor 19. In the reel exchange device shown in Fig. 1 , the position sensor 19 is an inductive sensor that generates a position signal by the method shown in Fig. 2 on the basis of a piece of aluminium tape 32 attached to a known position on the outer surface of the paper reel 4a. In this case, the aluminium tape 32 is placed on the outer surface of the paper reel 4a so that when it is at the location of the position sensor 19, the splicing point 31 on the paper reel 4a is just going under the drive belts 6 of the reel rotating device 5. For the position sensor 19, a separate mounting arm is installed on the frame as shown in Fig. 1.

Furthermore, the reel exchange device 1 shown in Fig. 1 comprises an apparatus 11 for removing a glue protection according to the invention, intended for removing glue protections attached onto the glue in the splicing area formed in advance on the outer surface of the topmost revolution of paper web in the paper reel. The apparatus is implemented so that it can be used in a way according to the method of the invention.

The embodiment of the apparatus for removing glue protection shown in Fig. 1 comprises mounting frames 12 for blowing nozzles, pivot arms 13 for the mounting frames, pivoting devices 14 for the mounting frames, blowing nozzles 15, control valves 16, distance sensors 17, safety switches 18, compressed air tanks 20, a pressurizer 21 , as well as a control unit 22 and 25, and a control panel (not shown in the figures).

In this case, there are two mounting frames 12 for blowing nozzles, because in this embodiment there are also two pairs of adjacent blowing nozzles 15 to be attached to them, one pair at each pair of drive belts. In this case, the mounting frames 12 for blowing nozzles are formed of a C-profile beam, on which suitable mounting protrusions are fixed for the blowing nozzles 15, the safety switch 18 and the distance sensor 17. The pivot arms 13 for the mounting frames are flat steel bars fixed to the mounting frame 12, one bar (on the side of the pivoting device for the mounting frame) being provided with a rotating arm 23, to which the movable end 24 of the pivoting device 14 for the mounting frame is mounted in a swivelled manner. The pivot arms 13 for the mounting frames are mounted on bearings on the central shaft of the outer drive belt pulley of the reel rotating device 5 so that the pivot arms and the mounting frames 12 for the blowing nozzles connected to them can be turned towards or away from the upper surface of the paper reel 4a with respect to the central shaft of the drive belt pulley.

In this embodiment, the pivoting devices 14 for the mounting frames are electrical spindle motors known as such. Their fixed end 25 is mounted on bearings on a supporting arm 26 connected to the mounting structures of the outer drive pulley of the reel rotating device, and the moving end 24 is mounted on bearings in the above-described manner on the rotating arm 23 belonging to the pivot arm of the second mounting frame. For this reason, moving the movable end 23 of the pivoting device (outwards or inwards) will turn the pivot arm 13 of the mounting frame (active pivot arm), whose other end is provided with the mounting frame 12 for blowing nozzles, to which frame, in turn, the blowing nozzles 15, the safety switch 18 and the ultrasound sensor 17 are connected, as well as the second pivot arm mounted on the other end of the mounting frame 12 (passive pivot arm). As the length of the pivot arms 13 is selected so that the blowing nozzles 15 hit the outer surface of the paper reel, if they are turned sufficiently in the direction of the outer surface of the reel, the pivoting devices 14 can be used to adjust the distance of the blowing nozzles 15, the ultrasound sensor 17 and the safety switch 18 from the outer surface of the paper reel 4a.

In this embodiment, there are a total of four blowing nozzles 15. In this printing machine shown in Fig. 2, the glue protections 30 on the paper reel are only placed at locations facing the drive belts 6; therefore, the blowing nozzles 15 extend in this embodiment only approximately over an area with the width of the drive belts 6. In this case, two blowing nozzles 15 are installed at each pair of drive belts and mounted next to each other on the mounting frames 12 (in other words, the device comprises one drive belt for blowing nozzles). A mounting protrusion 27 for blowing nozzles, being part of the mounting frame 12 for blowing nozzles, is fixed to the mounting frame to be turned and locked in a desired position by means of a fixing screw. Thanks to this, the position of the blowing nozzles 15 in relation to the outer surface of the paper reel 4a can be adjusted to achieve a blowing angle that is as good as possible. The ends of the blowing nozzles 15 have an elongated shape; that is, the blowing nozzles are of a so-called air knife type. The pair of blowing nozzles coming to the location of each pair of drive belts is coupled to a separate compressed air connection with a control valve 16. The blowing nozzles 15 are oriented so that when the mounting frame 12 is turned in the blowing position, the blowing nozzles 15 are approximately in the direction of rotation of the paper reel 4a mounted on the spindle 3, but still slightly inclined to the outer surface of the paper reel. Thus, the air flow to be blown by the blowing nozzles 15 will remove (peel off) the glue protections attached to the outer surface of the paper reel as effectively as possible. In this embodiment, the control valves 16 are magnetic valves fitted in compressed air connections common to the blowing nozzle pairs. The control valves 16 are used to control the operation of the blowing nozzles 15, that is, to start and stop the blowing of compressed air. The control valves 16 being placed in this way, the blowing of compressed air can be controlled in pairs of blowing nozzles |n this embodiment. In connection with normal operation, the aim is to open and close the control valves 16 for both pairs of blowing nozzles as simultaneously as possible. The electronic control signals for the control valves 16 are generated in a control unit that determines the moments for opening and closing the blowing nozzles.

The distance sensors 17, one in each mounting frame, function as devices for measuring the distance between the blowing nozzles 15 and the outer surface of the paper reel 4a. The distance sensors 17 are thus fixed to the respective mounting protrusions so that they are directed approximately transversely to the surface of the paper reel when the mounting frame and the blowing nozzles are in the normal blowing position. The distance sensors 17 are coupled to the control unit 22, wherein the measurement results of the distance sensors can be used in the control unit for controlling the pivoting devices for the mounting frames in such a way that the blowing nozzles 15 can be brought to a precisely predetermined distance from the surface of the paper reel 4a, irrespective of possible variations in the diameter of paper reels.

The safety switches 18, also one in each mounting frame 12, are limit switches coupled to control the pivoting device 14 of the mounting frames. When the switch is coupled, the spindle motor used as the pivoting device 14 stops and an alarm lamp is lit in the control panel. The safety switches 18 are connected to the blowing nozzles 15 so that when the mounting frame 12 is turned towards the paper reel (counterclockwise seen from the direction of Fig. 1 ), the coupling lever of the safety switch 18 touches the surface of the paper reel 4a and turns on the switch about 5 mm before the blowing nozzles 15 would touch the surface of the paper reel 4a. In this way, the safety switches 18 form a safety device that prevents the pivoting devices 14 from turning the blowing nozzles 15 against the surface of the paper reel 4a. The coupling lever 30 for the safety switches 18 is made of a flat metal piece that does not damage the outer surface of the paper reel when touching it. The compressed air tanks 20, one for each pair of blowing nozzles in this embodiment, are intended for securing a sufficient air flow intensity and pressure during blowing, by enabling a temporary production of compressed air that is significantly greater than the amount of air that can be obtained from a compressed air network for the time of blowing. In this case, the volume of the compressed air tanks 20 is about 6 I. An air pressure that is clearly higher than the air pressure in the compressed air network is produced in the compressed air tanks 20 by means of the pressurizer 21. In this embodiment, the pressure is about 20 bar at the beginning of blowing, and it goes down to about 18 bar during a normal blowing period. Pneumatic hoses 28 are led from the pressurizer into the compressed air tanks 20, and pneumatic hoses 29 are led from the compressed air tanks to the pair of blowing nozzles. Because of a significantly greater volume flow, the pneumatic hoses 29 leading to the blowing nozzles are larger in diameter than the pneumatic hose 28 leading to the pressurizer.

The pressurizer 21 is a pneumatic mechanical device known as such for increasing the air pressure to be formed in the pressure vessels higher than the pressure of pressurized air to be taken from a compressed air network. The pressurizer 21 comprises two cylinders and pistons of different sizes. The larger piston of the input side, driven by compressed air of the compressed air network, moves the smaller piston that pumps air into the output side. In this way, on the secondary side of the piston of the primary side, a pressure is produced that is equal to the relation of the piston diameters x the pressure on the primary side. The pressurizer - 21 is coupled to the compressed air network of the factory, wherein the device does not comprise a separate air compressor in this embodiment.

The control unit 22 comprises programmable logics known as such, for controlling the control valves 16 of the blowing nozzles, the pressurizer 21 , as well as the spindle motors operating as the pivoting devices 14 for the mounting frames. For determining the moments of starting and stopping the blowing nozzles 15, a control signal to indicate the reel change of the reel exchange device 1 is coupled to the inlet ports of the control unit. In this way, information on the beginning of a reel change is obtained from the control device of the reel exchange device 1. Furthermore, the inlet ports of the control unit 22 receive the distance signal from the distance sensors 17 and the coupling signal of the safety switch 18, as well as the position signal from the position sensor 19 of the reel exchange device 1 , other necessary control signals of the reel exchange device 1 (for example, the control signals of the bonding roll 9), and a rotational speed signal given by a device for measuring the rotational speed of the paper reel 4a. On the basis of this information, the control unit 22 can determine the most suitable moments for starting and stopping the blowing of compressed air as well as control the operation of the device 11 for removing the glue protection. The control panel 30 (not shown in the figures) is, in this case, integrated in the control panel of the reel change device by providing it with the switches for turning on the device for removing the glue protection and with an alarm lamp indicating the position of the safety switch 18. In addition to the main switch, the control panel comprises several switches for turning on both pairs of blowing nozzles. Thus, when the device is used, it is possible to use only one of the two pairs of blowing nozzles, when the other is turned off, if desired.

The device 11 for removing the glue protection of a paper reel shown in Fig. 1 is used during the operation of changing paper reels as follows: The new paper reel 4a is prepared by attaching glue protections of paper 30 as well as an aluminium tape 32 at the location of splicing 31 the paper reel as shown in Fig. 2. After this, in good time before the old paper reel 4b starts to approach its residual diameter, the new paper reel 4a is installed in place of the previous old paper reel (of which only a remainder reel is left). When the old paper reel 4b that is still in use further approaches its residual diameter, the reel rotating device 5 is turned to the upper position, the drive of the paper reel 4b is changed from the drive belts to the spindle, and the swivelling frame 2 is turned 180° in relation to the reel mandrels so that the new paper reel 4a turns up (underneath the reel rotating device) and the old paper reel 4b comes down (into the position shown in Fig. 1). After the old paper reel 4b has been unwound further and has received its residual diameter, the reel rotating device 5 turns down again, against the new paper reel, and starts to rotate the new paper reel 4a. At this stage, the control unit 22 checks, by means of the distance sensors 17, the distance between the blowing nozzles and the outer surface of the paper reel, and adjusts it to be suitable by running the pivoting devices 14 for the mounting frames. After the outer surface of the new paper reel 4a has achieved the same peripheral speed as the running speed of the paper web 8 unwound from the old paper reel, the bonding roll 10 under the new paper reel 4a is turned against the old paper web 8 so that the paper web is pressed against the outer surface of the new paper reel 4a. The moment of turning of the bonding roll 10 is determined by means of the position sensor 19 and the aluminium tape 32 on the surface of the new paper reel so that, at this moment of turning of the bonding roll 10, the glue protections 30 of the new paper reel 4a are under the drive belts 6. After a delay that is dependent on the rotational speed of the new paper reel 4a and the time of opening of the control valves 16, the control unit 22 switches the control valves 16 to open. Thus, the blowing nozzles 15 start to blow compressed air obliquely towards the paper reel 4a in parallel to the direction of rotation and just before the slicing point 31 on the outer surface of the new paper reel and the glue protections 30 therein turn to the blowing nozzles 15. After the slicing point 31 has turned to the blowing nozzles 15, a strong air flow with a flowing rate significantly faster than the peripheral speed of the reel causes the detachment of the glue protections 30 from the surface of the paper reel. After this, the slicing point 31 turns under the bonding roll 10 where the slicing point 31 is, by the effect of pressure caused by the bonding roll 10, glued onto the upper surface of the paper web unwound from the paper reel. Thus, the tip of the paper web on the new paper reel is detached, and the new paper web starts to run with the old paper web forward in the process of the printing machine. At the same moment when the bonding takes place, a cutting edge 33 in connection with the bonding roll is turned against the old paper web and cuts it off. After the cutting of the old paper web, paper web will be unwound from the new paper reel. The splice 31 of the paper webs will be removed from the paper web in the later steps of the process. In this embodiment, the blowing time of the blowing nozzles is about 50 to 150 ms. During this time, the air pressure in the compressed air tanks 20 drops from 20 bar to about 18 or 19 bar, depending on the blowing time. The pressurizer 21 will restore the pressure in the compressed air tanks back to the initial value before the next reel change. In this way, the device for removing the glue protections will be ready to remove the glue protections from a new paper reel again.

The device according to the invention for removing the glue protections of a paper reel can be implemented in a way that is, in many respects, different from the example embodiment presented above. For example, the number of blowing nozzles can be only one, or there may be several of them next to each other. In the method according to the invention, the paper reel can be equipped with a glue protection over the width of the whole paper reel, or, as in the above-presented example embodiment, separate glue protections can be provided at the drive belts or pulleys only. According to these alternative solutions, it is thus possible to use either blowing nozzles effective over the whole width of the paper web, or blowing nozzles effective over a given area in the width direction only. Also, for example the methods for determining the moment of blowing of the blowing nozzles and the position of the splice may vary. In some applications, it is possible to provide the glue protection with an indicator means, from which an inductive, optical or otherwise contactless positioning sensor detects the splicing point and uses it for determining the suitable moment for blowing. By means of several position detectors, the blowing time can be optimized to be as short as possible. An advantage of the short blowing time is the possibility to use smaller compressed air tanks and a larger momentary quantity of air. In some embodiments of the method, the edge of the glue protections on the side of the blowing nozzles can be made to extend outside the glue area. This will facilitate the detachment of the glue protection. Alternatively, the detachment of the glue protection can be facilitated by making the adhesion of the glue weaker in an area with the width of, for example, 1 to 2 mm, from the rear edge of the splicing point, and by maintaining the adhesion of the glue in the other areas. This can be done, for example, by applying suitable powder onto this area to reduce the tackiness of the glue. Furthermore, the detachment of the glue protections can be improved by dividing the glue protection into two or more parts in the width direction of the paper reel. The method according to the invention is most suitable for the reel exchange devices of such gravure printing and paper machines, in which the paper reel is rotated by means of drive belts or pulleys and in which the use of glue protections is necessary. However, since the use of glue protections makes it possible to use glues that dry clearly faster than before, and thereby faster running speeds during reel changes than before, the use of the method and the device according to the invention would also be very advantageous in such printing and paper machines, in which glue protections are currently not in use. Such printing and paper machines normally include those rotary printing and paper machines, in which the paper reels are rotated by rotating the spindle only.

The invention is not limited to the presented advantageous embodiments, but it may vary within the scope of the inventive idea presented in the claims.

Claims

Claims:

1. A method for removing a glue protection (31) at a splicing point (30) on a paper reel (4a, 4b), in which method the glue protections (30) attached onto a glue or tape at a splicing point (31) on a paper reel (4a, 4b) mounted on a reel exchange device (1) in a printing or paper machine or a corresponding machine for processing a paper web are removed by means of compressed air, characterized in that the glue protections (30) of the paper reel (4a, 4b) are removed by blowing compressed air to the glue protections (30) by means of at least one pneumatic nozzle (15) oriented in the foward direction in relation to the direction of rotation of the paper reel (4a, 4b).

2. The method according to claim 1 , characterized in that the glue protections (30) are blown during the last revolution of the new paper reel (4a) before the splicing of the paper web unwound from the new paper reel (4a) to the paper web (8) unwound from the old paper reel.

3. The method according to claim 1 or 2, characterized in that the suitable moment for starting the blowing is determined by means of a position indicator (32) attached to the paper reel (4a, 4b) and a position sensor (19), and that the suitable blowing time is determined on the basis of the rotational speed of the paper reel (4a, 4b).

4. The method according to any of the claims 1 to 3, characterized in that the detachment of the glue protector (30) attached to the splicing point (31 ) of the paper reel (4a, 4b) is facilitated by making the glue less tacky at the rear edge of the glue protection (30), by extending the glue protection (30) over the rear edge of the glueing area, or by dividing the glue protection (30) into separate parts in the width direction of the paper reel.

5. An apparatus for removing the glue protection (30) at a splicing point (31 ) on a paper reel (4a, 4b), which apparatus comprises pneumatic devices (15, 16, 20, 21 , 28, 29) for removing a glue protection (30) attached onto glue or a tape at a splicing point (31) on a paper reel (4a, 4b) mounted on the reel exchange device (1) of a printing or paper machine or a corresponding machine for processing a paper web, by means of compressed air, characterized in that the apparatus comprises at least one pneumatic nozzle (15) oriented in forward direction in relation to the direction of rotation of the paper reel, for blowing compressed air to the glue protection (30) in forward direction in relation to the direction of rotation of the paper reel (4a, 4b).

6. The apparatus according to claim 5, characterized in that the apparatus comprises means (19, 22, 32) for determining the moment of time and duration of blowing.

7. The apparatus according to claim 5 or 6, characterized in that the apparatus comprises a frame (12) for mounting the blowing nozzles, on which the blowing nozzles (15) are mounted and which is mounted on the reel exchange device (1) to be adjustable in relation to the paper reel (4a, 4b) by means of an actuator (14).

8. The apparatus according to any of the claims 5 to 7, characterized in that the apparatus comprises at least one distance measuring device (17) for measuring the distance between the blowing nozzles (15) and the outer surface of the paper reel (4a, 4b).

9. The apparatus according to any of the claims 5 to 8, characterized in that the apparatus comprises at least one compressed air tank (20) and a pressurizer (21) for securing a sufficiently high air flow rate and quantity.

10. The apparatus according to any of the claims 5 to 9, characterized in that the apparatus comprises a safety switch (18) for preventing collisions between the blowing nozzles (15) and the paper reel (4a, 4b).