Method and Device for Exchange of a Belt

Abstract

The invention relates to a method and a device for the exchange of an old working belt (1) on a machine for production of a web, for example a paper web, for a new working belt (13). According to the invention, the exchange is simplified, whereby the track start of the new belt is connected to the old belt, the old belt is made to circulate and thus draws the new belt around such that the new belt adopts the position of the old belt. A joint is then made between two facing ends of the new belt. Said drawing device is embodied such as to permit the old belt for exchange to be pushed from one side of the machine. The device comprises a frame (12) with two transverse elements (12.2, 12.3), which enclose the old belt between them in the assembled state. One transverse element (12.2) supports a roll (13.1) of the new belt and the other transverse element (12.3) supports a winding device (18) for winding on the old belt.

Description

This invention relates to a machine for producing a web made of paper or paperboard or a film material for example. In this case said invention relates to a working belt within such a machine, in particular a worn felt belt or mesh belt on a paper machine.

An essential component of a paper machine is the press section. Said press section has a multiplicity of presses through which felt belts are passed together with the still wet paper web in order to absorb water from the paper web and discharge the water again in some other position.

The felt belts are exposed to wear to a high degree. Hence they must often be exchanged. For this purpose the felt belt is severed when the machine is at a standstill. Then a new felt belt is mounted by wrapping it around the group of rollers—press rollers, guide rollers and the like—in question. Then the two ends of the felt belt are joined together and connected to each other by means of a seam. Nowadays, presses and formers are constructed in cantilever design for the purpose of exchanging skins, and use is made of seamless meshes and seamless felts. According to the prior art, making a seam is non-problematic and can be carried out easily and quickly. By contrast, mounting a felt belt requires a certain input of time and labor. The procedure for exchanging a felt belt takes several hours, generally between two and three hours. During this time the machine is at a standstill, which means lost production.

It is the object of the invention to disclose a method and a device with which it is possible to exchange an old, worn working belt with a new working belt more quickly, more reliably and with less input of time and labor, above all when exchanging a felt or a mesh on a paper machine. Also, the quality of the seam should be faultless.

Said object is accomplished by the features of the independent claims.

The essential idea of the invention is the following: The new belt is provided in roll form. The beginning of the new belt is fixed to the old belt. The old belt is first clamped in place and then severed. Then the old belt is wound up, and because of its connection to the new belt it takes the new belt with it and guides the new belt through the individual press nips or around the individual rollers until the new belt has fully adopted the former position of the old belt. Finally, the new belt is turned into an endless belt or a closed belt loop by making a seam.

According to an idea which takes the invention further, a belt-pull is fastened to the beginning of the new working belt (felt belt or mesh belt). Said belt-pull generally comprises only one narrow strip which is fixed to the beginning of the working belt, expediently to the middle of the belt, meaning half way along its width. The belt-pull can be made of a completely different material than the working belt. The only requirement is that it can exert a pull. Said belt-pull exists similarly in roll form; it is rolled onto the new working belt.

Unlike the main idea of the invention, the beginning of the belt-pull and not the beginning of the new working belt is fixed to the old working belt. The remaining procedure is the same as with the main idea: The old working belt is fixed, then its beginning is fastened to a winding core. The winding core is set in rotation, whereby the old belt pulls the belt-pull behind it. The advantage of this is that the machine can now be cleaned without the cleaning work and/or servicing work being obstructed by the old belt or the new belt. Then the belt-pull is connected to the new belt (this could also be done sooner). Then the belt-pull is wound onto the winding core and the new belt is mounted.

The advantages of the invention can be summarized as follows, explained with reference to a press section of a paper machine, representative for all cases of application in which a working belt has to be exchanged on a machine for producing a moving web:

• • Exchanging an old felt belt with a new one is easy and takes relatively little time;
  • The construction of the machine is easy to design: The felt belt is mounted as a belt with two ends and a seam is produced after mounting; hence the supports of the press section do not have to be opened, but at the operator end and the driven end they have bearing structures which can be in one piece and thus do not require any removable spacers (not a so-called cantilever design);
  • The new felt belt is treated gently while being mounted, hence it is free of damage after the mounting;

The felt belt does not have to be draped before being mounted in the press section, unlike in the method described in “Wochenblatt für Papierfabrikation” 21/1986;

• • The hall crane is not permanently needed for mounting the felt belt;
  • Positioning the two ends of the new felt belt is performed exactly and without any special labor input;
  • The inventive device for mounting the new felt belt can be prepared already while the paper machine is running;
  • The safety of personnel assigned to exchange the felt can be assured by suitable measures.

The invention will be explained in more detail with reference to the figures. In the drawing:

FIG. 1 shows, in a side view looking from the operator side, a part of the press section of a paper machine with mounting device.

FIG. 2 shows, in an enlarged representation, the mounting device according to FIG. 1 prepared for exchanging the felt.

FIG. 3 shows the item from FIG. 2 in a position turned through 90 degrees.

FIG. 4 shows the item from FIG. 2 with an old and a new felt belt after said belts have been connected to each other.

FIG. 5 shows the item from FIG. 4 after the old felt belt has been severed and at the beginning if it being wound up.

FIG. 6 shows the item from FIG. 5 with a fully wound-up old felt belt and with a new felt belt shortly before making a seam.

FIG. 7 shows in turn a mounting device similar to the one according to FIG. 6 but designed for a felt belt running at an angle.

FIG. 8 shows a mounting device on which a winding core and a new felt belt roll are mounted.

FIG. 9 shows a mounting device on which a winding core and a new felt belt roll are mounted on a horizontal element.

FIG. 10 shows, in a side view, a mounting device which is assigned to a felt loop as part of a press.

FIG. 11 shows in turn, in an enlarged representation, a mounting device in a view similar to FIG. 10.

FIG. 12 shows the item from FIG. 11, whereby the old felt belt has been fully or largely removed from the machine.

The following details can be seen in FIG. 1:

The illustrated press section comprises a top felt and a bottom felt. The case in question concerns the top felt, which is referred to in the following as the “old felt belt” 1. The old felt belt 1 has the form of an endless felt belt loop. The old felt belt 1 enwraps a number of guide rollers 2 to 7. The guide roller 2 is a tensioning guide roller with which the old felt belt 1 can be tensioned. The old felt belt passes, together with the bottom felt (which does not need to be gone into any further at this point), through a press formed from two press rollers 8 and 9. During operation, a paper web (not illustrated here) runs together with the two felt belts through the press nip, which is formed from the press rollers 8 and 9, and is enclosed hereby like a sandwich between the felt belts.

Tubular suction devices 10,11 can also be seen.

The essential item is the mounting device 12, whose details will be considered in the following. Said mounting device can be pushed, with the help of a crane, from the operator end onto the old felt belt 1. It already carries the new felt belt 13, which has been wound up into a roll 13.1.

The construction of the mounting device 12 can be recognized more clearly in FIGS. 2 and 3. To be noted in FIG. 3 are the two symbols for the operator on the left and for the motor on the right corresponding to the operator end and the driven end. The mounting device is constructed accordingly from three main elements, namely a rigid vertical connecting element 12.1, which is situated on the operator end, and two horizontal elements 12.2 and 12.3, which in the built-in state are situated respectively above and below the felt belt 1. The length of the two horizontal elements can be the same size as or somewhat narrower or wider than the width of the felt belt 1. The mounting device 12 is thus open from the driven end such that it can be pushed onto the felt belt 1 (not illustrated here) from the operator end.

The mounting device 12 comprises the following additional elements: In the upper horizontal element it carries a bearing for the new felt belt roll 13.1. At least one brake 14 is also there. The brake 14 is used to check the tension of the new felt belt 13 while it is being unwound. The upper horizontal element 12.2 carries in addition a securing device 15 with at least one eyelet 15.1 for fastening at least one operator safety belt.

The lower horizontal element 12.3 has one clamping device 16 and 17 respectively on the operator side and the driven side. It also carries a wind-up station 18 in the form of a spiked roller.

The new felt belt roll 13.1 can be recognized in FIG. 4. A short length of the new felt belt 13 is wound off said new felt belt roll and fixed to the old felt belt 1. If the old felt belt 1 runs around—from left to right in the illustration—then it will take the new felt belt 13 along with it and guide it in this case around all the mentioned guide rollers 2 to 7 and through the press rollers 8 and 9.

Before this happens, the old felt belt 1 is fixed by means of the clamping devices 16 and 17 and then severed. Then it is fixed by its beginning to the spiked roller 18—see FIG. 5. The spiked roller 18 is equipped with a drive. The drive sets the spiked roller in rotation such that the old felt belt 1 is wound up. Of course the clamping devices 16 and 17 must be released first.

The wound-up state is shown in FIG. 6. The felt belt roll 1.1 formed from the old felt belt can be recognized there. Also visible there are the two ends of the new felt belt 13 which has now been pulled in. The ends of the new felt belt 13 are fixed with the help of the clamping devices 16 and 17. The rest of the new felt belt 13 is wound off a felt belt roll. The ends of the new felt belt 13 are laid parallel and close to each other. A zip fastener (not shown here) is now fixed to the two ends and closed. Then a seam is made, whereupon the clamping devices 16 and 17 can be released. Finally the zip fastener is removed. The mounting device 12 has fulfilled its purpose. It is dismantled with the help of a crane. In the meantime the old felt belt roll 1.1 was placed on the floor of the paper machine where it can be processed further.

A particularly interesting variant of the inventive method is not presented in the figures but can be performed without further ado using the mounting device shown. In this case provision is made for a belt-pull as was previously mentioned above. The belt-pull is fixed to the beginning of the new felt belt 13, namely best of all to the middle of said belt's width extension. It is also possible for the new felt belt 13 to converge to a point at its beginning and for the mentioned belt-pull to be fixed to said point. Instead of the beginning of the new felt belt 13 being fixed to the old felt belt 1, now the beginning of the belt-pull is fixed to the old felt belt 1—again to the middle of the belt. The belt-pull has a length which is at least equal to the length of the old felt belt 1 or somewhat larger than this length. The procedure is essentially the same as for a procedure without the use of a belt-pull. The advantage of the belt-pull is that the old felt belt 1 can be essentially wound up first. Then the machine is free of all skins and can be cleaned.

The inventive method with the use of a belt-pull now proceeds as follows:

First the mounting device 12 is fitted with a roll, namely the new felt belt roll 13.1, onto which the belt-pull is then wound. Thus equipped, the mounting device is moved by means of a crane into the correct position as shown in FIG. 1.

Then the beginning of the belt-pull is fixed to the old felt belt 1 no differently than can be seen in FIG. 4, which shows a direct connection of the old felt belt 1 and the new felt belt 13.

Then the old felt belt 1 is clamped, severed and fixed to the spiked roller 18. The clamp is then released and the old felt belt 1 wound onto the spiked roller 18, whereby the belt tension is controlled with the help of the brake 14.

As the interim result the old felt belt 1 is fully wound up into a felt belt roll and the belt-pull is in the position in which the old felt belt 1 was previously found.

The machine can now be cleaned.

Thereafter the spiked roller 18 is made to rotate again. Consequently, the belt-pull is wound up onto the old felt belt roll 1.1 and the new felt belt 13 is mounted simultaneously. In other words, the new felt belt 13 now occupies the position of the old felt belt 1 in that it enwraps all the guide rollers and press rollers as did the old belt previously.

Now the two clamping devices 16, 17 are activated. The rest of the new felt belt 13 is now wound off so that two ends of the new felt belt lie opposite and parallel to each other. A zip fastener is fitted, a seam is made, the zip fastener is removed and the device dismantled.

The procedure proceeds very quickly. The time it takes lies in the magnitude of 1.5 hours compared to 2 to 3 hours in accordance with the prior art.

In principle it is possible to push the drawing device from either side of the machine onto the old belt to be exchanged. However, pushing it on from the operator end is to be preferred.

The device is expediently designed and arranged such that in the working state it adopts the position as shown in FIG. 1. In this case the old belt extends through the mounting device 12 in horizontal direction. Also, it is located in the uppermost region of the old belt 1 to be exchanged, meaning between the two uppermost guide rollers 6 and 7. However, the mounting device can also be arranged in a different position, e.g. in a lower position or tilted toward the horizontal.

It is also possible to push the mounting device onto a belt 1 running at any angle. The mounting device can then be designed as shown in FIG. 7. The left, horizontal longitudinal support 12.2.1 and the corresponding clamping device 16 can then be arranged lower or higher than the right, horizontal longitudinal support 12.2.2 and the corresponding clamping device 17.

On the embodiment according to FIG. 8, a winding core 18 and the new felt belt roll 13.1 are fitted to an upper horizontal element 12.2, hence above the old felt belt 1 or the new felt belt 13 or the belt-pull.

The drive for the winding core 18 can be positioned anywhere. Ideally it is arranged in the center of the winding core 18 as illustrated. In this case the drive can be a direct drive, for example with a plug-on motor, or a chain drive or cardan shaft drive. Also, the positions of the winding core 18 and the new felt belt roll 13.1 could be swapped such that the winding core 18 is located to the right of the new felt belt roll 13.1.

On the embodiment according to FIG. 9 it is possible to recognize the winding core 18 and the new felt belt roll 13.1. They are fitted however to the lower horizontal element 12.3, hence below the old felt belt 1 or the new felt belt 13 or a belt-pull. The drive of the winding core 18 can be positioned anywhere but again preferably in the center of the winding core 18 as shown in FIG. 9. Here, too, the positions of the winding core 18 and the new felt belt roll 13 can be swapped.

It goes without saying that the winding core 18 on the embodiments according to FIG. 8 and FIG. 9 can also be omitted or do not need to be fitted in advance.

The press of a paper machine presented in FIG. 10 has two press rollers 30, 40 which are enwrapped respectively by a felt belt. In this case it is the lower felt loop formed by the old felt belt 1.

The mounting device 12 can be seen. Said mounting device carries a winding core 18 and the new felt belt roll 13.1. Tubular suction devices 10 and 11 are again assigned to the old felt belt 1. The beginning of the new felt belt 13 is already connected to the old felt belt 1.

The mounting device 12 is arranged particularly cleverly on this embodiment. Namely, in this case there is no need to clamp the old belt 1 before it is severed. The old belt 1 is prevented simply by gravity from moving too far away from the winding core 18 (optional) after said belt is severed. The position of the belt end is thus assured through the arrangement of the mounting device 12.

On the embodiment in FIG. 11 provision is made for a belt-pull 19 which is connected at a connection point 20 to the old felt belt 1. Instead of one belt-pull it is possible for two or more belt-pulls to be provided and, accordingly, for a corresponding number of connection points 20 to be available. The other end of the belt-pull 19 is connected to a drive unit 21. After the old belt 1 is severed below the connection point 20, the end of the old belt 1 which is not connected to the belt-pull or belt-pulls 19 moves away from the severance point 20. The old belt can be wound onto a winding core 18. The dead weight of the old belt 1 causes it to be moved out of the machine. If necessary, a pulling force can be applied in addition at the free end of the belt—in the figure alongside the winding core 18—by hand or with the help of the drive of the winding core 18 for example. The speed with which the old belt 1 is conveyed out of the machine is defined by the drive unit 21 which acts as a brake. Because of its connection to the belt-pull or belt-pulls 19 the old belt 1 is not conveyed any faster out of the machine than the drive unit or drive units allow the belt-pull or belt-pulls to follow behind.

On the embodiment according to FIG. 12, the old belt 1 has been fully or at least largely removed from the machine and wound up onto the winding core 18 for example. The connection point 20 can be disconnected and the belt-pull or belt-pulls connected to the drive unit or drive units 21. It is also possible, however, for the belt-pull or belt-pulls to be wound up likewise onto the winding core 18 if one is being used. The other end of the belt-pull or the belt-pulls is disconnected from the drive unit or drive units 21 and connected to the beginning of the new belt 13, which is on the roll 13.1. See the connection point 22. The new belt 13 is pulled into the machine by activating the drive unit or drive units (either 18 or 21). When the new belt 13 has adopted the former position of the old belt 1, the belt loop is rendered endless by making a seam.

Claims

1. Method for exchanging an old felt belt or mesh belt or other working belt with a new belt provided in roll form (13.1) on a machine for producing a paper web or a paperboard web or some other web made from another flat material; characterized by the following features: 1.1 the beginning of the new belt (13) is fixed to the old belt (1); 1.2 the position of the old belt (1) is secured in front of the fixing point looking in the mounting direction; 1.3 the old belt (1) is coupled directly or indirectly to a drive unit; the secured positioning of the old belt (1) is canceled; 1.5 the drive unit is activated, whereby the old belt (1) takes the new belt (13) with it until the new belt (13) has adopted the former position of the old belt (1); 1.6 the positions of the beginning and/or the end of the new belt (13) are secured prior to connecting; 1.7 an endless belt loop is formed from the new belt (13) by making a seam; 1.8 the fixing of the new belt (13) to the old belt (1) is canceled.

2. Method for exchanging an old felt belt or mesh belt or other working belt with a new belt on a machine for producing a paper web or a paperboard web or a web made from another flat material; characterized by the following features: 2.1 the new belt (13) is provided in roll form (13.1); 2.2 the beginning of at least one belt-pull is fixed to the old belt (1); the position of the old belt (1) is secured in front of the fixing point looking in the mounting direction; the belt-pull or belt-pulls are fixed to the old belt (1); 2.5 the secured positioning of the old belt (1) is canceled; 2.6 the drive unit is activated, whereby the old belt (1) takes the belt-pull or belt-pulls with it until the required region is free of the old and/or new belt (1) or (13); 2.7 the end of the belt-pull or belt-pulls is firmly connected to the beginning of the new belt (13); 2.8 the drive unit is activated or remains activated, whereby the belt-pull or belt-pulls take the new belt (13) with them until the new belt (13) has adopted the former position of the old belt (1); 2.9 the positions of the beginning and/or the end of the new belt (13) are secured prior to connecting; 2.10 an endless belt loop is formed from the new belt (13) by making a seam; 2.11 the fixing of the belt-pull or belt-pulls to the new belt (13) is canceled;

3. Method according to claim 1, characterized in that the old belt (1) is wound up into a belt roll (1.1).

4. Method according to claim 2, characterized in that the belt-pull is wound up separately from or together with the old belt (1).

5. Method according to claim 1, characterized in that a pulling force can be applied respectively to the old belt (1) and/or to the new belt (13) and/or to the belt-pull or belt-pulls for the purpose of exchanging the belt.

6. Method according to claim 2, characterized by the following features: 6.1 a pulling force is applied to the belt-pull or belt-pulls; 6.2 the free end of the old belt (1), which is not connected to the belt-pull or belt-pulls, is lowered by its own dead weight and/or by an additional action of force such that the belt-pull or belt-pulls on the other end of the belt (1) are inserted into the machine again.

7. Method according to claim 1, characterized in that the machine is cleaned after winding up the old belt (1) and, where applicable, the belt-pull into a belt roll (1.1).

8. Method according to claim 1, characterized in that the belt tension of the belts is established or controlled during the winding up.

9. Method according to claim 1, characterized in that in order to make a seam the two ends of the new belt (13) are brought together and fitted with a zip fastener and that the seam is then made and the zip fastener removed again.

10. Device for exchanging an old felt belt or mesh belt or other working belt with a new belt on a machine for producing a paper web or a paperboard web or a web made from another flat material, characterized by the following components: 10.1 there is provided a frame (12) comprising at least one first transverse element (12.2) located between two longitudinal elements (12.2.1, 12.2.2); 10.2 the transverse element (12.2) carries a bearing for receiving a roll (13. 1) of the new belt in a position in which the axis of the roll (13.1) extends transverse to the running direction of the old belt (1); 10.3 there is provided an apparatus for making a seam between two adjacent ends of the new belt (13); 10.4 there is provided at least one drive device for the old belt (1) and/or for the new belt (13) and/or for a belt-pull or belt-pulls.

11. Device according to claim 10, characterized in that there is provided a brake (14) for establishing or controlling the belt tension during mounting.

12. Device according to claim 10, characterized in that there is provided on one of the transverse elements (12.2, 12.3) a winding core (18) for winding up the old belt (1).

13. Device according to claim 12, characterized in that the winding core comprises a spiked roller.

14. Device according to claim 10, characterized in that one of the transverse elements (12.2,12.3) is constructed as a seam platform.

15. Device according to claim 10, characterized in that the length of the belt-pull is greater than or equal to the length of the old belt (1).

16. Device according to claim 10, characterized in that the two transverse elements (12.2, 12.3) and the segment (12.1) joining them together has a C-shaped form looking in the web running direction.

17. Device according to claim 16, characterized in that the two transverse elements (12.2, 12.3) and the segment (12.1) can be turned into a closed frame by an additional segment.

18. Device according to claim 1, characterized in that the device is permanently installed.

19. Device according to claim 1, characterized in that the device is mobile.

20. Device according to claim 10, characterized in that at least one bearing is provided to receive a roll (13.1) of the new belt (13).