Machine and method

Abstract

The invention relates to a machine for producing or machining a fibrous web, comprising a Yankee cylinder for drying and / or smoothing the fibrous web, and a transfer roller, which can be placed on the Yankee cylinder thereby forming a transfer nip, wherein the machine further comprises a marking roller, which can be placed on the Yankee cylinder thereby forming a marking nip, wherein the marking nip is arranged downstream of the transfer nip, seen in the running direction of the fibrous web, and the machine has a covering, more particularly a marking felt, wherein the covering is arranged around the marking roller in the form of a covering loop and is guided through the marking nip. According to the invention, the marking roller and preferably also the transfer roller is / are designed as a bending compensation roller.

Description

[0001] Machine and process

[0002] The invention relates to a machine for producing or processing a fibrous web, in particular for producing machine-finished paper (MG paper), and to a method for changing a clothing of a machine for producing or processing a fibrous web.

[0003] For the production of one-sided smooth specialty papers combined with a very high specific bulk, paper machine concepts with an MG cylinder + hot-air hood as the central drying unit are used. Such paper machines are known, for example, from documents DE102017118218 A1 and DE102017118222 A1. Such typically large heated MG cylinders are also called Yankee cylinders. In this application, these two terms are used synonymously.

[0004] By applying a moist paper web to a hot MG cylinder, a very high gloss and smoothness are created on the underside of the paper web. This, in combination with a high specific bulk of the paper, is achieved because, unlike in a calender, the gloss and / or smoothness are not generated in a calender nip by high line loads, which compress the paper.

[0005] When using MG papers in packaging (e.g., bakery bags), in addition to the high one-sided gloss, special line patterns on the paper surface that serve a purely visual function may be required. A variety of different pattern types have become established on the market.

[0006] These special lines can be realized with the help of a press, often in combination with a marking felt at the inlet of the MG cylinder, since the paper web there has an ideal moisture content in the range of 40-58% and thus the visual contrast can be developed.

[0007] To date, these lined papers have been produced exclusively on older, slow-running, and narrow MG machines with widths of up to approximately 4m. It would, of course, be desirable to make the described marking possible using a marking felt for new, high-speed, and wide MG machines as well, or to be able to produce the described products on these machines under economically viable conditions.

[0008] Surprisingly, it turns out to be a challenge that these wide, high-speed lines offer such high production capacity. While a previous line could be fully utilized with such ruled qualities, in modern lines, ruled qualities generally only account for a certain, small proportion of total production. In addition, there can be a multitude of different marking patterns, each requiring its own marking felt. This results in frequent grade changes during production.

[0009] The object of the invention is to propose a machine with which special papers can be reliably produced even with large machine widths.

[0010] It is a further object of the invention to propose a machine which can be operated economically even with small production quantities of individual varieties and frequent changes of varieties during production.

[0011] The present invention further aims to design the machine in such a way that a wide covering - e.g. a marking felt with a width of up to 9 m - can be pressed selectively onto the paper web on the MG cylinder (on / off) and, in addition, the felt change times must be as short as possible.

[0012] This is intended in particular to enable a high overall plant efficiency of the new paper machines.

[0013] The objects are achieved by a machine according to independent claim 1 and a method for changing a covering according to independent claim 9. Advantageous embodiments are described in the dependent claims.

[0014] With regard to the machine, the object is achieved by a machine for producing or processing a fibrous web, comprising a Yankee cylinder for drying and / or smoothing the fibrous web, and a transfer roller that can be placed against the Yankee cylinder to form a transfer nip. Furthermore, the machine comprises a marking roller that can be placed against the Yankee cylinder to form a marking nip, wherein the marking nip is arranged downstream of the transfer nip in the direction of travel of the fibrous web.

[0015] The machine further comprises a covering, in particular a marking felt, wherein the covering is arranged in the form of a covering loop around the marking roller and is guided through the marking nip.

[0016] According to the invention, it is provided that the marking roller and preferably also the transfer roller is or are designed as a deflection compensation roller.

[0017] Typically, the fibrous web is a paper web, for example an MG paper web.

[0018] The terms "covering" and "felt" or "marking felt" are used synonymously in this application, as marking felt is by far the most common application in connection with the marking roller. However, it is possible that a fabric, film, or other suitable covering is used instead of a marking felt.

[0019] Yankee cylinders for use in this invention can be cast iron cylinders, for example. However, the use of Yankee cylinders with a steel shell is also very advantageous.

[0020] Yankee cylinders are usually heated by applying hot steam under a certain pressure from the inside. This causes the Yankee cylinder to deform. The cylinder is essentially inflated. This effect is particularly significant at the leading and driving edges of the Yankee cylinder. While the jacket is significantly deformed outward, the end caps remain largely unchanged. Therefore, the surface of the Yankee cylinder exhibits a strong gradient in this edge area.

[0021] It is known, for example from EP 3 974 576 A1, to use a so-called deflection compensation roller in combination with the Yankee cylinder as a transfer roller. Unlike conventional rollers, which are cylindrical or have a fixed crown, deflection compensation rollers allow the profile of the marking nip to be precisely adjusted across the width, and thus also the profile of the contact pressure. Deflection compensation rollers are also referred to as bending compensation rollers. The applicant company markets such rollers under the brand name NipCo Walzen.

[0022] The transfer of the fibrous web to the Yankee cylinder preferably takes place in the area of ​​such a deflection compensation roll attached to the Yankee cylinder. This ensures uniform pressure, particularly in the area of ​​the edges, and a stable transfer of the web to the Yankee cylinder.

[0023] According to the present invention, a so-called deflection compensation roller is now used, in particular, as the marking roller. Such deflection compensation rollers are also referred to as deflection compensation rollers or NipCo (NipCorrect) rollers.

[0024] The wider the Yankee cylinder, the more pronounced the phenomenon of deformation of the Yankee surface. And the wider the Yankee cylinder, the greater the risk that, when using conventional rollers as marking rollers, the pressure of the roller or the clothing (especially the marking felt) on the paper web will vary across the width of the fibrous web, which can lead to uneven markings on the paper web. Compensation by generally increasing the pressure is not desirable, as this would lead to over-pressing of the web in other places and a reduction in the specific volume of the web. Using a deflection compensation roller, the marking nip can be precisely controlled, thus allowing the marking pattern of the fibrous web to be precisely adjusted.Especially with Yankee cylinder widths of 6m and more, especially 7m, 8m or 9m and more, the use of a deflection compensation roller as a marking roller is very advantageous.

[0025] The use of a deflection compensation roller as a marking roller also offers advantages because the machine needs to be optimized for frequent grade changes. For different grades, the machine operates with different steam pressures in the Yankee cylinder, resulting in significantly different deformations. These can be compensated for using the deflection compensation roller, ensuring a consistent marking nip and a consistent marking pattern on the fiber web.

[0026] In many cases it will be useful for the machine to have a transfer clothing for transporting the fibrous web to the Yankee cylinder, whereby the transfer clothing is guided together with the fibrous web through the transfer nip.

[0027] In advantageous embodiments, at least one, and in particular all, deflection compensation rollers may comprise a rotatable shell made of a fiber composite material, in particular a GRP shell, which in particular has an outer coating made of a polyurethane. GRP (glass fiber reinforced plastic) is a material made of plastic and glass fibers.

[0028] Pressing can be carried out, for example, by means of a bending compensation roll with elastic material made of a GRP composite material, such as a NipcoFullFlex roll with convex support sources, or pressing can be carried out by means of a shoe press roll, such as a NipcoFlex-T roll as in tissue machines, ie a shoe roll with a concave pressure shoe with a QualiFlex casing.

[0029] A deflection compensation roll with an elastic cover can be used, such as the so-called NipcoFullFlex roll, which is significantly more flexible than a steel or cast iron cover and can therefore better follow the contour of the Yankee cylinder. This type of roll differs from a shoe roll in that, among other things, it does not use a concave shoe as a support source, but rather several convex support sources, usually closely spaced and adjacent to one another, across the length of the roll or the width of the machine. This type of cover consists of a CFRP or GFRP cover with an outer polyurethane coating. This type of cover is more flexible than a steel or cast iron cover, so it can adapt better to the changing contour of the Yankee cylinder.With such a pressure roller (marking roller and / or transfer roller) arranged on the Yankee cylinder, there is a good adaptation to the respective Yankee cylinder deformation, a uniform line force distribution in the transverse direction and uniform quality properties with regard to thickness, smoothness and gloss.

[0030] In preferred embodiments, two deflection compensation rollers can be arranged on the Yankee cylinder, each in separate, independent clothing loops. The first of the two rollers is referred to as the 'transfer roller', the second as the 'marking roller'. In each clothing loop, a cantilever roller can be inserted, a

[0031] The deflection compensation rolls adapt ideally to the respective crowning condition of the Yankee cylinder, which results from different steam pressures in the Yankee cylinder.

[0032] The first deflection compensation roller, including a possible associated protective felt loop as transfer clothing, has the task of transferring the paper web to the MG cylinder and fixing it there evenly in the CD direction (i.e. in the cross-machine direction).

[0033] The second deflection compensation roller, located behind it in the running direction, creates a marking, e.g. a line embossing on the paper web surface, using its own rotating marking felt.

[0034] The second nip, called the marking nip, can optionally be swiveled away / retracted, allowing a paper web to be produced without a line marking.

[0035] Fast and non-destructive felt change

[0036] Due to potentially small production quantities of the respective marked paper grades, especially lined paper grades, the marking felts are generally far from worn out when the felt is changed. Therefore, it makes neither economic nor ecological sense to cut up and dispose of the old marking felt when changing the felt, as is usually the case. Rather, it is desirable if this felt can be reused in the next production run of the corresponding grade. Therefore, this invention also aims for a non-destructive felt change concept.

[0037] To solve these problems, the inventors have developed various ideas that are inventive both individually and in combination with each other.

[0038] In order to be able to produce additional different embossing patterns and to quickly exchange them, a special change concept for the marking felt was developed, consisting of the following elements:

[0039] • a pivoting marking roller that can be extended from the machine as a bending compensation roller

[0040] • a cantilever frame which allows the use of endless felts

[0041] • an automatic storage system for a tension roller

[0042] • a felt changing concept including a 2-way changing frame.

[0043] This makes it possible to remove the marking felt from the machine without causing any damage (without having to cut it as usual) so that it can be reused in a later production run.

[0044] In addition, a new marking felt can be inserted very quickly, meaning that production can be restarted with a new pattern after a changeover time of 30-90 minutes.

[0045] For safety reasons, the marking felt cannot be removed while a machine section is running, which is why the felt changeover time is of great importance for system efficiency. Several solutions have been developed for this.

[0046] Idea 2.1 Extraction device of the marking roller including hydraulic cylinder for roller positioning and locking of the extraction device

[0047] In advantageous embodiments, the machine can be provided with an extension device for moving the marking roller laterally out of the machine. In particular, the extension device can be provided with an extension rail and an extension support connected to the marking roller, wherein the extension support is movable along the extension rail and can be removed from the machine together with the marking roller.

[0048] Furthermore, it may be advantageous that at least one lifting element is provided for pivoting the marking roller onto or away from the Yankee cylinder, which lifting element is connected to the marking roller and a frame part of the machine, wherein the lifting element is designed to be decoupled from the marking roller and / or the frame part.

[0049] In particular, it may be advantageous for the lifting element to comprise or consist of a hydraulic cylinder.

[0050] The marking roller can, for example, be extended to the operator's side of the machine using a permanently integrated device without the need for a crane. The marking roller can be decoupled from other machine components, such as the hydraulic cylinder, pivot bearing, etc., and extended from the machine in one go using a pulling device (manual or automatic). From there, the crane can pick up the entire roller in a single operation.

[0051] The marking roller can be connected or connectable to an extension support. This extension support can be guided in an extension rail and removed from the machine together with the marking roller. An alternative marking roller, if required, can then be attached to this extension support, which also serves as a retraction support, and reinserted into the extension rail.

[0052] A lifting element can advantageously be provided for pivoting the marking roller in and out. This lifting element is usually connected to both the marking roller and the frame. To change the marking felt or to extend and retract the marking roller, this lifting element can be decoupled from the roller or the frame. For example, the lifting element can be designed as a hydraulic lifting cylinder and can be decoupled from the marking roller. When the roller is extended—together with the extension support—the lifting element can remain on the frame in the machine.

[0053] Cantilever concept of the chair in this position

[0054] The cantilever and machine frame of the Yankee cylinder can be designed to accommodate two superimposed fabric guides (felt / wire), for example, with integrated deflection compensation rolls. Additional cantilever supports can be installed for the felt / wire run located below (supporting the main cantilever support).

[0055] Idea 2.2 Automatic storage system for the tensioning roller without crane provision

[0056] Furthermore, it may be advantageous if the machine comprises a tensioning roller, wherein the covering loop is arranged around the marking roller and the tensioning roller and is guided through the marking nip, and wherein means are provided in the machine to move the tensioning roller from a working position to a maintenance position.

[0057] The tension roller in the fabric loop can be moved into a storage position using a rotating or translational device. This occurs without the aid of a crane. This is advantageous because the crane is freely available for other tasks during this operation. This means that, in the overall context of the felt / screen change, valuable downtime can be minimized or saved. This is all the more important because a paper machine shop usually only has one overhead crane, and the availability or unavailability of this crane has a decisive influence on the duration of the maintenance downtime.

[0058] The maintenance position of the tension roller is selected so that the marking felt's covering loop is not under tension when the tension roller is in the maintenance position. This tension-free position is a prerequisite for removing or retracting the marking felt from the machine without damage.

[0059] Changing the covering

[0060] Furthermore, a method for changing the clothing of a machine for producing or processing a fibrous web is proposed. The machine comprises a Yankee cylinder for drying and / or smoothing the fibrous web, as well as a

[0061] Transfer roller which can be placed on the Yankee cylinder to form a transfer nip, wherein the machine further comprises a marking roller which can be placed on the Yankee cylinder to form a marking nip, wherein the marking nip is arranged after the transfer nip as viewed in the running direction of the fibrous web.

[0062] The machine further comprises a covering, in particular a marking felt, and a tensioning roller. The covering is arranged in the form of a covering loop around the marking roller and the tensioning roller and is guided through the marking nip. Furthermore, the machine provides means for moving the tensioning roller (6) from a working position to a maintenance position.

[0063] In addition, at least one lifting element is provided for pivoting the marking roller onto or off the Yankee cylinder, which lifting element is connected to the marking roller and a frame part of the machine, wherein the lifting element is designed to be decoupled from the marking roller and / or the frame part.

[0064] The marking roller and / or the transfer roller can be designed as a deflection compensation roller. This is not absolutely necessary for the process of changing the clothing. The process works equally well for machines in which the marking roller and / or the transfer roller are designed as classic rollers, e.g. as cambered rollers, in particular with negative camber. The process comprises the following steps: a. Moving the tensioning roller from the working position to the maintenance position b. Decoupling the lifting element from the marking roller and / or the frame part c. Providing a first changing unit for receiving the

[0065] Covering loop d. Transfer of the covering loop from the machine to the first

[0066] Exchange unit

[0067] In preferred embodiments, the method may further comprise the steps: e. Providing a second exchange unit onto which a second covering loop is mounted; f. Transferring the second covering loop from the second exchange unit into the machine so that the second covering loop is arranged around the marking roller and the tensioning roller; g. Coupling the lifting element to the marking roller and / or the framing part; h. Moving the tensioning roller from the maintenance position to a working position.

[0068] The felt / screen changing unit is designed to enable fast felt / screen changing times. The changing unit can be designed with location-defined guide rails (support bars) along the screen loop in the machine.

[0069] In an alternative embodiment of the method, it can be provided that the method steps c. and d. are carried out as follows: c. Providing a first exchange unit for receiving the

[0070] Covering loop, wherein a second covering loop is pulled onto the first changing unit d. Transfer of the covering loop from the machine to the first changing unit, wherein the covering loop is placed in particular onto the second covering loop.

[0071] In advantageous embodiments, the method may further comprise the following steps: f. Transferring the second covering loop from the first exchange unit into the machine so that the second covering loop is arranged around the marking roller and the tensioning roller, wherein in particular the first covering loop remains on the exchange unit g. Coupling the lifting element to the marking roller and / or the framing part h. Moving the tensioning roller from the maintenance position to the working position

[0072] With this variant of the process, a single change unit can be used to both remove the clothing from the machine and insert the second clothing into the machine. The provision of a second change unit and the back-and-forth movement of these change units are eliminated, further accelerating the clothing change.

[0073] In this version of the process, the fabric is pulled over the second fabric located on the first change unit when being removed from the machine. If one or both fabrics have a rough surface, this can prove difficult or require a lot of force.

[0074] Therefore, it may be advantageous to arrange a sliding layer between the covering loop and the second covering loop, with both the top and bottom surfaces having a lower roughness than the first covering loop and the second covering loop. This facilitates both the removal of the covering loop from the machine and the insertion of the second covering loop into the machine.

[0075] The sliding layer can be, for example, a polymer film or a smooth polymer tape.

[0076] Conveniently, the sliding layer can be wound onto a corresponding exchange unit using the second covering loop while the machine is still running. Thus, the provision of the sliding layer does not increase machine downtime.

[0077] Furthermore, it can be advantageous if the first exchange unit and / or the second exchange unit are designed as mobile exchange units, which can be moved, for example, by an overhead crane. This allows for the felt / screen to be quickly extended onto the empty exchange unit docked with the crane. The same applies to the insertion of the felts / screens using the docked, second exchange unit equipped with a felt / screen and the second covering loop.

[0078] It can advantageously be provided that such a mobile exchange unit has a plug-on pin, and the machine has a receptacle for the plug-on pin, and that when ready, the first exchange unit and / or the second exchange unit is positioned such that the plug-on pin is inserted into the receptacle.

[0079] The mobile exchange unit can be designed with a dome (=socket pin) to retract into the structurally adapted cantilever on the operator's side. This eliminates the need for the cantilever's protruding pin and simplifies access to the machine from the operator's side in this area.

[0080] It can be advantageous to have two similar mobile change units available. This allows the second clothing (felt / wire) to be newly mounted to be mounted on a first change unit before the machine is shut down. After the clothing from the machine has been mounted on the first change unit and removed from the machine during a stop, the second change unit can immediately dock onto the cantilever, and the new second clothing can be pulled into the machine. This further accelerates the clothing change.

[0081] The plug-in pin can, for example, be round, which makes it easier to dock the changing device.

[0082] The plug-in pin can also be non-round (rectangular, triangular, etc.). This ensures that the changing device is always optimally positioned after docking.

[0083] Alternatively, the first exchange unit can be designed as a stationary exchange unit. In this case, as part of the exchange unit, a number of guide rails and / or guide cables can be attached to the frame and, if necessary, to a counter bearing.

[0084] These guide rails or guide ropes can be installed on the operator's side of the machine while the machine is still running.

[0085] Likewise, the second fabric may already be mounted on the stationary change unit. It is also possible for a sliding layer to be mounted on this stationary change unit. All of this preparation can be done while the machine is still running. Furthermore, all of these preparation steps can be performed without the use of an overhead crane. This is different from the use of mobile change units, which usually require an overhead crane to transport the change unit due to its weight. The overhead crane can be used for other tasks while the stationary change unit is being set up.

[0086] In addition, it is possible, for example, that the machine described is part of a larger machine for producing a fibrous web, in particular a paper or board web, with a headbox, a forming unit, a press section, a pre-drying section, the described MG smoothing Yankee cylinder and a wind-up, wherein the pre-drying section is designed in particular for one-sided pre-drying of the fibrous web on its underside, as MG smoothing Yankee cylinder, for example, an overhead MG smoothing Yankee cylinder is provided, with which the underside of the fibrous web is brought into contact.In particular, in the web running direction (L) after the pre-dryer section and before the fibrous web runs onto the MG smoothing Yankee cylinder, a remoistening device can be provided for one-sided remoistening of the fibrous web on its underside and correspondingly for developing the moisture gradient in the z-direction of the fibrous web towards its underside.

[0087] However, other uses of machines according to aspects of the invention are also possible.

[0088] The invention is further explained below with reference to schematic figures. The invention is not limited to the embodiments shown here.

[0089] Figure 1 shows a machine according to one aspect of the invention

[0090] Figure 2 shows a machine according to a further aspect of the invention. Figure 3 shows a machine according to a further aspect of the invention. Figure 4 shows a machine according to a further aspect of the invention. Figures 5a, 5b and 5c show mobile exchange units according to further aspects of the invention.

[0091] Figures 6a, 6b, 6c and 6d show the steps of a clothing change with a stationary changing unit according to further aspects of the invention

[0092] Figure 1 shows a section of a machine for producing a special paper web, such as is used, for example, to produce so-called machine-finished papers (MG papers). An essential component of such a machine is a large, usually steam-heated cylinder 1, which is referred to as a Yankee cylinder or MG cylinder. The paper web is transported - usually with a moisture content in the range between 40% and 58% - from a transfer clothing 8 to the Yankee cylinder 1 and transferred to the Yankee cylinder 1 in a transfer nip 4. The transfer nip 4 is formed by the Yankee cylinder 1 and a transfer roller 2, which is attached to the Yankee cylinder 1. Particularly in the case of wide machines, which are, for example, 6 m wide or more, it is advantageous if the transfer roller 1 is designed as a deflection compensation roller. In the design according to Figure 1, in the running direction of the paper web, or MG cylinder,A marking nip 5 is arranged downstream of the transfer nip 4 in the direction of rotation of the Yankee cylinder 1. This marking nip 5 is formed by the Yankee cylinder 1 and a marking roller 3, which can be applied to the Yankee cylinder 1 to form the marking nip 5.

[0093] The machine also has a clothing 7, which is usually designed as a marking felt 7. This marking felt 7 is guided in a clothing loop around the marking roller 3 and a tension roller 6, as well as optionally further guide rollers, and thus also runs together with the paper web through the marking nip 5. Figure 1 shows a state in which the tension roller 6 is in a working position 6a, whereby the clothing 7 is under a suitable tension. A maintenance position 6b is also provided—for example, a suitable storage position. When the tension roller is in the maintenance position 6b, the clothing is not under tension, so that a change of the clothing is possible.

[0094] The paper web is smoothed on the side facing Yankee cylinder 1 and also acquires a certain gloss. To maintain the specific bulk of the paper, this smoothing takes place without the usual calendering.

[0095] The side of the paper web facing away from the Yankee cylinder 1 receives a marking, for example in the form of a line, in the marking nip 7 using appropriate marking felts 7. It is important that, despite the deformation of the Yankee cylinder 1 due to the application of steam, the marking nip 3 is very uniform across the entire width of the machine, as otherwise uneven markings on the paper would occur, which in the worst case scenario would lead to increased waste. Therefore, according to aspects of the invention, the marking roller 3 in the machine is designed as a deflection compensation roller.

[0096] A deflection compensation roller with a composite shell can be used, in particular, as a deflection compensation roller. Such a shell consists of a CFRP or GRP shell with an outer polyurethane coating. Such a shell is more flexible than a steel or cast iron shell, allowing it to adapt better to the changing contour of the Yankee cylinder 1. With such a marking roller 3 (and / or transfer roller 2) arranged on the Yankee cylinder 1, good adaptation to the respective Yankee cylinder deformation, a uniform line force distribution in the transverse direction, and consistent quality characteristics with regard to thickness, smoothness, and gloss are achieved.

[0097] In advantageous embodiments, both the marking roller 3 and the transfer roller 2 can be designed as deflection-compensating rollers, and in particular, both can have a composite casing as described above. The NipcoFullFlex rollers from the applicant are ideally suited for this purpose.

[0098] Figure 2 again shows the machine from Figure 1, but with a focus on the details of the marking roller 7. The machine again comprises two cantilevers 11, 12; one for each covering loop 7, 8. An extension rail 20 which extends in the transverse direction of the machine is attached to the cantilever 11 assigned to the marking felt 7 or the marking roller 3. An extension carrier 21 is guided in this extension rail 20. The marking roller 3 is attached to this extension carrier 21. This makes it easier to change the marking roller 3, as it can be pulled out and removed very easily along the extension rail 20, e.g. in the direction of the driver's side FS of the machine. Either the same marking roller 3 or an alternative roller can then be attached to the extension carrier 21 and fed back into the machine using the extension rail 20.

[0099] Figure 2 also shows lifting element 20, which serves to position or move the marking roller 3 to the Yankee cylinder 1. This lifting element 20 is designed here as a hydraulic lifting cylinder 20, which is connected both to the marking roller 3 (or its bearings) and to a frame part. In order to fully utilize the advantages of the extension device described above, the lifting element 20 in Figure 2 is designed so that it can be decoupled from the marking roller 3. The decoupled lifting element 22a then remains on the frame while the marking roller 3 is removed or replaced. The lifting element can thus serve both for roller positioning and for locking the extension device.

[0100] Figure 3 again shows a machine of the type shown in Figures 1 and 2. This shows a variant in which the tensioning roller 6 can be moved from the working position 6a to the maintenance position 6b without the use of external aids such as an overhead crane. This can be accomplished via a translational movement or a rotational movement, which can be performed, for example, along suitable rail elements. Since the use of the bottleneck resource of the overhead crane is again avoided, this feature contributes significantly to an accelerated change of the covering 7.

[0101] Figure 4 shows a machine whose frame comprises at least four cantilevers 11, 12, 13, 14. So-called spacers 15 are provided between the cantilevers 11, 12 or between the cantilevers 11, 12 and other frame parts. If, for example, the marking felt 7 needs to be replaced, the spacers 15 adjacent to the cantilever 11 can be removed, and the marking felt can be inserted or removed through the resulting openings.

[0102] Figures 5a, 5b and 5c go into more detail about a method according to a further aspect of the invention and explain the advantageous use of mobile exchange units 25, 26.

[0103] Figure 5a shows a side view of a change unit 25 suspended from a support element on an overhead crane. A support element extends centrally, with a mounting pin 28 provided at its front end. The change unit has guide rails 28 at least above and to the sides of the support element. The covering is placed on these guide rails 28 during the covering change.

[0104] Figure 5b shows a front view of such a change unit 25, 26. Here, a marking felt 7 is already mounted on the change unit 25, 26 and rests on the guide rails 28. This can, for example, be a second change unit 26 onto which an alternative marking felt 7 is mounted, which is then to be drawn into the machine.

[0105] As shown in Figure 5c, the plug-in pin 27 can be inserted into a corresponding receptacle on the driver-side FS end face of the cantilever 11. In the examples in Figures 5a - 5c, the plug-in pin 27 is designed as a round, cylindrical, or slightly conical plug-in pin 27. This facilitates the insertion of the plug-in pin 27 into the cantilever receptacle. In the situation shown in Figure 5c, the spacers 15 around the cantilever 11 have been removed so that the marking felt 7 can be pulled from the machine onto the change unit 25, or from the change unit 26 onto the machine. After the clothing change is complete, the spacers 15 can be reinserted.

[0106] Figures 6a, 6b, 6c and 6d show the steps of a clothing change with a stationary changing unit 25 according to further aspects of the invention.

[0107] Figure 6a shows the operator's side FS of a machine, wherein a covering loop 7, in particular a marking felt 7, is pulled onto the machine. In the situation shown in Figure 6a, the machine is usually still in operation. The frame of the operator's side with the cantilever 11 still has the corresponding spacers 15. During operation of the machine, a stationary changing unit 25 can be erected without the use of a crane, for example by installing a number of guide rails 28 and / or guide cables 29 as in Figure 6a. These guide rails 28 or guide cables 29 can be attached at one end to the frame, for example to the cantilever 11, and at the other end to a counter-bearing, such as a hall wall. Supported and shaped by these guide rails 28 or guide cables 29, a second covering loop 7b is pulled onto the stationary changing unit 25.This second covering loop 7b should be pulled into the machine in the shortest possible time during the next stoppage of the machine, while the covering loop 7 is removed.

[0108] To enable this covering change to be carried out even faster, a sliding layer 30 is provided in the changing unit 25 in Figure 6a. The sliding layer 30 serves to separate the covering 7 and the second covering 7b from each other during the covering change and to enable easier movement of the coverings over one another. For this purpose, it is advantageous if the sliding layer is smoother on its top and bottom sides than the coverings 7, 7b. The sliding layer 30 can be implemented, for example, as a polymer film or as a smooth polymer tape. In Figure 6a, the sliding layer 30 is implemented as a loop that is wound around the second covering loop 7b on the changing unit 25. Alternatively, it can also be provided, for example, that the sliding layer 30 is designed as a sliding cover, which is simply placed over the second covering loop 7b from above. In many cases, such a sliding cover is sufficient to achieve the desired effect.

[0109] Figure 6b shows the next step in a clothing change. In this situation, the machine is at a standstill. The tensioning roller 6 has already been moved from the working position 6a to the maintenance position 6b, and the lifting element 22 has been decoupled from the marking roller 3 and / or the frame part. Furthermore, the corresponding spacers 15 have been removed. The clothing loop 7 can now be pulled out of the machine. The clothing 7, for example a marking felt 7, is pulled onto the stationary changing unit 25. Advantageously - but not necessarily - the clothing loop 7 is pulled over the provided second clothing 7b. To avoid unnecessary force when pulling out due to the friction between the two clothings 7, 7b, the sliding layer 30 is retracted. This allows the clothing 7 to slide easily over the second clothing 7b.Figure 6c shows a state in which both the covering 7 and the second covering 7b are located on the stationary exchange unit 25.

[0110] Subsequently, as shown in Figure 6d, the second covering 7b can be pulled into the machine. During this pulling-in process, the sliding layer 30 also ensures easy movement of the coverings 7, 7b. It will be expedient to fix the sliding layer 30 during the movement of such a covering 7 or a second covering 7b to prevent accidental movement of this sliding layer.

[0111] Once the second clothing 7b has been retracted into the machine, the lifting element 22 can be coupled to the marking roller 3 and / or the frame part, and the tensioning roller 6 can be moved from the maintenance position 6b to the working position 6a, and the spacers 15 can be reinserted. The clothing change is then complete, and the machine can be restarted. The stationary change unit 25 can then be dismantled and the removed clothing 7 removed. This work then no longer influences the duration of the machine downtime. Furthermore, the change process shown here can be implemented entirely without the use of an overhead crane. As can be seen from Figures 5a - 5c and 6a - 6d, the design of the marking roller or transfer device is irrelevant for the described methods for changing the clothing, in particular whether it is a deflection-compensating roller or not.

[0112] List of reference symbols

[0113] 1 Yankee cylinder / MG cylinder

[0114] 2 transfer roller

[0115] 3 Marking roller

[0116] 4 handover ip

[0117] 5 Marking nip

[0118] 6 tension roller

[0119] 6a Working position

[0120] 6b Maintenance position

[0121] 7 Covering, marking felt, covering loop

[0122] 7b second stringing loop

[0123] 8 Transfer covering

[0124] 11 cantilevers

[0125] 12 cantilevers

[0126] 13 cantilevers

[0127] 14 cantilevers

[0128] 15 Intermediate piece

[0129] 20 extension beams

[0130] 21 Extension rail

[0131] 22 lifting element

[0132] 22 a decoupled lifting element

[0133] 25 exchange unit

[0134] 26 second exchange unit

[0135] 27 spigots

[0136] 28 Guide rail

[0137] 29 Guide rope

[0138] 30 sliding layer

[0139] FS Guide page

Claims

Patent claims 1 . Machine for producing or processing a fibrous web, comprising a Yankee cylinder (1 ) for drying and / or smoothing the fibrous web, and a Transfer roller (2) which can be placed on the Yankee cylinder (1) to form a transfer nip (4), wherein the machine further comprises a marking roller (3) which can be placed on the Yankee cylinder (1) to form a marking nip (5), wherein the marking nip (5) is arranged after the transfer nip (4) as viewed in the running direction of the fibrous web, and wherein the machine has a clothing (7), in particular a marking felt (7), wherein the clothing (7) is arranged in the form of a clothing loop around the marking roller (3) and is guided through the marking nip (5), characterized in that the marking roller (3) and preferably also the transfer roller (2) is or are designed as a deflection compensation roller.

2. Machine according to one of the preceding claims, characterized in that at least one, in particular all deflection compensation rollers comprise a rotatable shell made of a fiber composite material, in particular a GRP shell, which in particular has an outer coating made of a polyurethane.

3. Machine according to one of the preceding claims, characterized in that the machine has a transfer clothing (8) for transporting the fibrous web to the Yankee cylinder (1), wherein the transfer clothing (8) is guided together with the fibrous web through the transfer nip (4).

4. Machine according to one of the preceding claims, characterized in that the machine comprises an extension device for moving the marking roller (3) laterally out of the machine. Machine according to claim 4, characterized in that the extension device comprises an extension rail (21) and an extension support (20) which is connected to the marking roller (3), wherein the extension support (20) is movable along the extension rail (21) and can be removed from the machine together with the marking roller (3). Machine according to one of the preceding claims, characterized in that at least one lifting element (22) is provided for pivoting the marking roller (3) onto or off the Yankee cylinder (1), which is connected to the marking roller (3) and a frame part of the machine, wherein the lifting element (22) is designed such that it can be decoupled from the marking roller (3) and / or the frame part. Machine according to claim 6, characterized in that the lifting element (22) comprises or consists of a hydraulic cylinder (22).Machine according to one of the preceding claims, characterized in that the machine comprises a tensioning roller (6), wherein the clothing loop (7) is arranged around the marking roller (3) and the tensioning roller (6) and is guided through the marking nip (5), and wherein means are provided in the machine for moving the tensioning roller (6) from a working position (6a) to a maintenance position (6b). Method for changing a clothing (7) of a machine for producing or processing a fibrous web, comprising a Yankee cylinder (1) for drying and / or smoothing the fibrous web, and a. Transfer roller (2) which can be placed on the Yankee cylinder (1) to form a transfer nip (4), the machine further comprising a marking roller (3) which Formation of a marking nip (5) can be placed on the Yankee cylinder (1), wherein the marking nip (5) is arranged after the transfer nip (4) as viewed in the running direction of the fibrous web, and wherein the machine comprises a clothing (7), in particular a marking felt (7), and a tensioning roller (6), wherein the clothing (7) is arranged in the form of a clothing loop (7) around the marking roller (3) and the tensioning roller (6) and is guided through the marking nip (5), and wherein means are provided in the machine for moving the tensioning roller (6) from a working position (6a) into a maintenance position (6b), and wherein at least one lifting element (22) is provided for connecting orPivoting the marking roller (3) onto the Yankee cylinder (1) is provided, which is connected to the marking roller (3) and a frame part of the machine, wherein the lifting element (22) is designed such that it can be decoupled from the marking roller (3) and / or the frame part, characterized in that the method comprises the steps of: a. Moving the tensioning roller (6) from the working position (6a) into the maintenance position (6b) b. Decoupling the lifting element (22) from the marking roller (3) and / or the frame part c. Providing a first changing unit (25) for receiving the covering loop (7) d. Transferring the covering loop (7) from the machine to the first changing unit (25).

0. Method according to claim 9, characterized in that the method additionally comprises the steps of: e. Providing a second changing unit (26) onto which a second covering loop is pulled. f. Transferring the second covering loop from the second exchange unit (26) into the machine so that the second covering loop (7b) is arranged around the marking roller (3) and the tensioning roller (6). g. Coupling the lifting element (22) to the marking roller (3) and / or the framing part. h. Moving the tensioning roller (6) from the maintenance position (6b) to the working position (6a). 11 Method according to claim 9, characterized in that method steps c. and d. are carried out as follows: e. Providing a first changing unit (25) for receiving the covering loop (7), wherein a second covering loop (7b) is pulled onto the first changing unit (25) f. Transferring the covering loop (7) from the machine to the first changing unit (25), wherein the covering loop is placed in particular onto the second covering loop (7b).

12. Method according to claim 11, characterized in that a sliding layer (30) is arranged between the covering loop (7) and the second covering loop (7b), wherein in particular both the upper side and the lower side have a lower roughness than the covering loop (7) and the second covering loop (7b).

13. A method according to any one of claims 11 or 12, characterized in that the method further comprises the steps of: i. Transferring the second covering loop from the first Change unit (25) into the machine so that it has second A covering loop (7b) is arranged around the marking roller (3) and the tensioning roller (6), wherein in particular the first covering loop (7) remains on the changing unit (25). j. Coupling the lifting element (22) to the marking roller (3) and / or the framing part. k. Moving the tensioning roller (6) from the maintenance position (6b) into the working position (6a). Method according to one of claims 9 to 13, characterized in that the first changing unit (25) and / or the second changing unit (26) is designed as a mobile changing unit (25, 26) which has a slip-on pin (27), and the machine has a receptacle for the slip-on pin (27), and that when ready, the first changing unit (25) and / or the second changing unit (26) is positioned such that the slip-on pin (27) is inserted into the receptacle.Method according to one of claims 9 to 13, characterized in that the first changing unit (25) is designed as a stationary changing unit (25) which has a number of guide rails (28) and / or guide cables (29) which are fastened to the frame and optionally to a counter bearing.

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