DE29811048U1 - Press arrangement - Google Patents

Description

Press roll and press arrangement with at least one such press roll

The invention relates to a press roll for treating a fibrous web, in particular a paper or cardboard web, in at least one press nip formed with a respective counter surface, with a non-rotatably mounted carrier, a press cover running around the carrier and at least one support device arranged between the carrier and the press cover, via which the press cover is supported on the carrier in the area of a respective press nip. It also relates to a press roll according to the preamble of claim 34. The invention also relates to a press arrangement for treating a fibrous web, in particular a paper or cardboard web, in which at least one such press roll is used.

A press roll of the type mentioned is known, for example, from DE-U-92 03 395. In this known press roll, which is a shoe press roll, the press cover is supported in the usual way via at least one support device on a solid stationary yoke, which serves as a bending support and is thus bent according to the respective loads. Such a bending of the yoke can, however, have a detrimental effect on the shoe and cover guide. In particular, it can lead to desired deviations from a given starting position of this shoe and cover guide.

In the known press roller, the influence of a deflection of the yoke occurring transversely to the press plane is counteracted by the fact that the respective press shoe is mounted so that it can move relative to the yoke. However, this does not yet achieve sufficient positional stability of the shoe and casing guide. This is particularly true in the case where such a press roller is used, for example, as a central roller between two other press rollers and the supporting forces therefore act in different directions.

The aim of the invention is to create a press roll and a press arrangement of the type mentioned at the beginning, in which a highly positionally stable press cover guide and thus also the most optimal web and/or felt guide are always guaranteed, as independently as possible of the respective operating conditions.

With regard to a first embodiment variant according to the invention relating to the press roller, this object is achieved in that means are provided for influencing the deflection of the carrier.

As a result, the carrier can be influenced by the means in question in such a way that a deflection of the carrier caused by the forces in the area of the press gap(s) is at least substantially compensated. In particular, automatic compensation is possible using the means in question. A straight and stable starting position is always obtained regardless of the pressure level set at any given time. This means that there are no significant geometric changes to the press roller, especially when the line force is increased or decreased. In addition, the side shields also experience

There is no longer any inclination of the respective press cover clamping due to the lack of beam bending. As a result, the press cover, the respective press felt and the fibrous web always run smoothly.
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In DE-A-33 17 455, a press roll is already known in which the press jacket rotates around a hollow support that is mounted in a rotationally fixed manner and is supported on the inside by a support device on an inner bending support. However, this does not include an external support device located between the outer support and the inner support that enables variable adjustment of the support forces.

The press roller can, for example, comprise two support devices spaced apart from one another in the circumferential direction, by means of which the press jacket is supported on the carrier in order to form at least two press gaps with respective counter surfaces. In this case, the deflection of the carrier can be influenced by the means in question in such a way that a resulting deflection caused by the differently directed pressing forces is at least substantially compensated.

The means for influencing the deflection of the support can be implemented in different ways. For example, a bimetallic support can be provided. In this case, the means for influencing the deflection include means for heating the support. It is also conceivable, for example, to use a slotted support which is braced in the desired manner by appropriate means.

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A further expedient embodiment of the press roll according to the invention consists in that at least one inner and/or at least one outer auxiliary support is assigned to the support and the means for influencing the deflection comprise means for mutual radial bracing of these supports.

In a preferred practical embodiment, the support is provided as an outer hollow support, to which a rotationally fixed inner support is assigned, wherein the means for influencing the deflection comprise means for a suitable radial bracing of the hollow support and the associated inner support.

The respective clamping can be carried out hydraulically, pneumatically, mechanically, thermally and/or electromagnetically.

If the means for influencing the deflection of the support comprise at least one support device arranged between a hollow support and an inner support, this support device preferably comprises at least one row of support elements extending transversely to the direction of web travel. If a hollow support and an inner support are used, these are expediently mounted equidistantly at their ends.

The press roll can in particular be a shoe press roll with a flexible press cover. At least one support device arranged between the carrier and the press cover can have at least one press shoe and several support elements arranged in a row extending transversely to the web travel direction.

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which can be formed, for example, by respective cylinder/piston units. In principle, the support elements of a support device arranged, for example, between a hollow support and an inner support can also comprise such cylinder/piston units. 5

A preferred practical embodiment of the press roller according to the invention is characterized in that it comprises two outer support devices arranged between the hollow support and the press jacket, which are spaced apart from one another in the circumferential direction and by means of which the press jacket is supported on the hollow support in the area of two press gaps to be formed with a respective counter surface, and at least one inner support device arranged between the hollow support and the inner support, by means of which the deflection of the hollow support can be influenced in such a way that a resulting deflection of the hollow support caused by the differently directed pressing forces is at least substantially compensated. The direction of action of the inner support device is preferably in the resulting direction of action of the two outer support devices.

For example, in the case that the support forces applied by the two outer support devices are at least substantially equal and the radial directions of action of the two outer support devices are offset by approximately 120°, all three forces applied by the two outer support devices and the inner support device can be at least substantially equal, so that an equilateral triangle of forces is formed. In such a case in particular, the rows of support elements of the two outer support devices and the inner support device can have the same pitch and their support elements

elements have the same piston area. The two outer support devices and the inner support device can then be subjected to the same, preferably variably adjustable, pressure, for example. The forces generated by the two outer support devices and the inner support device are therefore in equilibrium, with the direction of action of the inner support device lying in the bisector between the two radial directions of action of the two outer " support devices.

In a further expedient embodiment of the press roller, in which the forces applied by the two outer support devices are again at least substantially equal, they form an isosceles triangle of forces with the force applied by the inner support device. In this case too, the rows of support elements of the two outer support devices can again have the same pitch and their support elements can have the same piston areas. In order to generate a force that at least substantially compensates for the resulting force of the two outer support devices, the total piston area of the inner support device is then preferably adjusted accordingly. This can be done, for example, via the number of support elements, whereby the individual piston areas of these support elements assigned to the inner support device are preferably the same size as the individual piston areas of the support elements of the two outer support devices. The rows of pistons of the two outer support devices and the inner support device can again be subjected to the same, preferably variably adjustable, pressure. The direction of action of the inner support device is also in this case in the bisector between the two radial directions of action of the

both outer support devices. Except for a small percentage deviation that may still exist due to the selected whole divisions in the row of support elements assigned to the inner support device, all forces are back in equilibrium. 5

With such a design of the press roller, which involves an isosceles triangle of forces, in which the total piston surface of the inner support device is adjusted accordingly to generate a force that at least substantially compensates for the resulting force of the two outer support devices, this total surface can also be adjusted accordingly via the size of the individual piston surfaces. The row of support elements of the inner support device has the same pitch as the rows of support elements of the two outer support devices. All rows of support elements can also be subjected to the same, preferably variably adjustable, pressure. In addition, the direction of action of the inner support device is also in the bisector between the two radial directions of action of the two outer support devices. Apart from a possible small percentage deviation due to the selected standard piston diameter in the row of support elements assigned to the inner support device, which may not exactly match the calculated diameter, all forces are thus in balance again.

In principle, such an embodiment of the press roll according to the invention is also possible in which the forces applied by the two outer support devices are of different magnitude and, together with the force applied by the inner support device, an unequal-sided

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Form a triangle of forces. In this case, the rows of support elements of the two outer support devices can have an unequal division and/or their support elements can have piston surfaces of different sizes.
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In this case too, the total piston surface of the inner support device can be adjusted accordingly to generate a force that at least substantially compensates for the resulting force of the two outer support devices. Since the forces applied by the two outer support devices are of different magnitudes, in the present case the direction of action of the inner support device is not in the bisector between the two radial directions of action of the two outer support devices. The two outer support devices and the inner support device can again be subjected to the same, preferably variably adjustable, pressure. As a result, all forces are again in balance here. In addition, in this case the pressure shoes can be the same width when viewed in the direction of web travel. This has the advantage that only one reserve shoe is required.

In a further advantageous embodiment of the press roller according to the invention, the forces applied by the two outer support devices and the inner support device are kept in balance via the individual pressures acting on the support elements. In this embodiment, the effective directions of the various support devices as well as the piston surfaces and divisions or distances between the support elements can be freely selected. In this embodiment, however, the control effort is somewhat greater.

In particular, in the case of the embodiments which each involve an equilateral or isosceles force triangle, the pressure profiles resulting in the various press nips can be adapted in the desired manner, for example, by selecting the respective shoe width measured in the direction of web travel.

The pressure shoes can be equipped with a double piston pressure in order to vary the pressure curve in the press gaps.

An advantageous embodiment of the press roll according to the invention is characterized in that the press jacket is offset relative to the hollow carrier in the roll cross-sectional plane, whereby larger shoe widths are possible in particular.

Starting from a press roll of the type specified in the preamble of claim 34, the above-mentioned object is further achieved in that an outer hollow support guiding the press jacket and an inner support are provided and that the press jacket is supported directly on the inner support by means of a respective support device through the hollow support jacket. The support device preferably comprises at least one press shoe guided on the hollow support and at least one support element by means of which the press shoe is supported directly on the inner support.

Here, the outer hollow beam serves only to guide the press jacket. There is no direct transfer of press gap support forces through the hollow beam. However, it absorbs the lateral shoe support force, which

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the friction force in the relevant press gap. As a result, the outer hollow support is not subjected to bending. Rather, it remains straight during operation. The support forces are absorbed by the inner support, which can bend freely in all directions without negatively affecting the shoe, press cover, felt and/or web guide. The respective support devices and thus the relevant press gaps can be adjusted separately. In addition, the pressure shoes can be the same width. Finally, the support elements can have pistons located inside the roller. The thermal load on such internal pistons is relatively low compared to direct shoe pressure.

The support elements can each be coupled to the respective press shoe via a joint.
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The support force applied by a particular support device is suitably adjustable.

Even in this variant according to the invention with a press jacket supported directly on the inner carrier through the hollow carrier jacket, the hollow carrier and the inner carrier are preferably mounted equidistantly at their ends.

In a preferred practical embodiment of the press roll according to the invention, at least two support devices are provided in order to support the press jacket in the region of at least two press gaps spaced apart from one another in the circumferential direction.

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the support forces applied by the various support devices preferably separately adjustable.

In both embodiments of the press roll according to the invention, it can be advantageous if the press jacket is guided in a polygonal manner at least in sections, preferably at least between the two extended press gaps. Such a polygonal jacket guide supports the water being thrown off the press jacket. A water scraper is therefore no longer required, which is particularly advantageous in a confined installation space. In practice, it has been shown that such a polygonal jacket guide does not have a detrimental effect on the jacket running time.

If at least part of the dewatering is to be carried out by such a water spin-off, the press jacket of the press roll according to the invention is preferably blindly drilled and/or grooved.

The press roll according to the invention, preferably designed as a shoe press roll with a flexible press cover, can be used with particular advantage in a press arrangement in which it is provided as a central roll between two further press rolls in order to form a press nip with each of these that is extended in the direction of web travel.

This eliminates the need for the expensive and complex press suction roll that was previously used. In such a press arrangement, the entire dewatering can take place, for example, via the two extended press nips formed by the central shoe press roll. In principle, however, another extended press nip can be provided in the press arrangement,

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which is then formed, for example, between a counter roll that interacts with the central shoe press roll and another roll, in particular a shoe press roll. A maximum of three press nips extended in the direction of web travel are therefore sufficient, resulting in a volume-saving dewatering process. The first press nip extended in the direction of web travel can in particular be double-felted, which achieves symmetrical dewatering. The second press nip extended in the direction of web travel is expediently single-felted, whereby dewatering with little remoistening is guaranteed in this nip. The problems that arose in previous multi-roll presses as a result of deflection are practically eliminated by the design according to the invention. Mutual press nip influence is excluded over the entire line force range. The use of cambered rolls is no longer necessary. Cylindrical rolls can now be used instead. Accordingly, harder roll covers are also possible, which results in longer service lives and higher machine availability. Overall, fewer roller types need to be provided.

In addition to the press cover of the central shoe press roll, the counter roll that forms the first extended press gap can also be blind-drilled and/or grooved, so that the drainage of both extended press gaps can be carried out at least partially by spinning water off into channels and, in particular, the first extended press gap can be drained on both sides by spinning water off into a respective channel. This means that lighter felts can be used. In addition, they are easier to condition, which means that less vacuum is required on the pipes.

mammals or the like. As a rule, only two felts are required instead of three.

Since the previously used large press suction roller with a thick cover is no longer required, the vacuum requirement is significantly reduced. Overall, significantly less drive power is achieved. In addition, a simple, lever-free and compact frame is possible. All press gaps have a closed power flow. Since the entire press load can be specified via a common pressure line, safe and simple machine control is also possible. Overall, operating costs are significantly lower.

In a preferred practical embodiment of the press arrangement according to the invention, a continuously closed web guide is provided. The fibrous web can be guided between the two extended press nips formed by the shoe press roll around a deflection roll, preferably designed as a suction roll.

It is particularly advantageous if a transfer felt or belt is guided through the second extended press nip formed with the shoe press roll, viewed in the web travel direction, and the fibrous web is guided after the second extended press nip together with this transfer felt or belt via a deflection roll, preferably designed as a suction roll, preferably to a subsequent drying section.

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As already mentioned, the press jacket of the shoe press roll and/or at least one of the press rolls forming an extended press gap with the shoe press roll can be blind-drilled and/or grooved. This allows the drainage of at least one extended press gap to be carried out at least partially by throwing water into at least one channel or the like.

Overall, this results in an advantageous press concept with a closed web guide, at least two shoe presses without a press suction roll and press gap drainage, in particular by water centrifugation.

The invention is explained in more detail below using exemplary embodiments with reference to the drawing, in which: 15

Figure 1 is a schematic, partially sectioned representation

a first embodiment of a press arrangement comprising a central shoe press roll,

Figure 2 is an enlarged cross-sectional view of the central

Shoe press roll of the press arrangement shown in Figure 1,

Figure 3 shows a schematic longitudinal section through the

Central shoe press roll shown in figures 1 and 2,

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Figure 4 shows a schematic longitudinal section through the right

End of the central shoe press roll shown in Figures 1 and 2 with a modified bearing,

Figure 5 is a schematic, partially sectioned representation

a further embodiment of a press arrangement with a central shoe press roll, the press jacket of which is offset relative to the hollow beam when viewed in the roll cross-sectional plane, 10

Figure 6 which extends in the direction of web travel over the press nip of the

Embodiments according to Figures 1 and 5 resulting pressure curve,

Figure 7 is a schematic, partially sectioned representation

a further, alternative embodiment of a press arrangement comprising a central shoe press roll,

Figure 8 is an enlarged cross-sectional view of the central

Shoe press roll of the press arrangement shown in Figure 7 and

Figure 9 shows a schematic longitudinal section through the

Central shoe press roller shown in figures 7 and 8.

Figure 1 shows in a purely schematic, partially sectioned representation a first embodiment of a press arrangement for treating a

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a fibrous web 10, which is taken over by a screen belt 16 in the area of a suction roller 12 by an upper felt 14 and is then fed between the upper felt 14 and a lower felt 18 to a first press nip S1 extended in the web running direction L. The fibrous web 10 is then fed together with the upper felt 14 to a second press nip S2 extended in the web running direction L.

As can be seen from Figure 1, the two press nips S1 and S2, which are extended in the web travel direction L, are formed between a central shoe press roller 20 and two counter rollers 22, 24 associated with it, which are supported on the inside in the area of the press nips S1 and S2, respectively, and which in this case are deflection compensation rollers. While the roller 22 is arranged directly below the central shoe press roller 20, the further roller 24 is arranged diagonally above this shoe press roller 20. Following the second press nip S2, which is extended in the web travel direction L, the fibrous web 10 is separated from the upper felt 14 and taken over by the counter roller 24, whereupon it is fed to a downstream offset press comprising the two rollers 26, 28. Following this roller press, the fibrous web 10 is taken over by a drying screen 32 in the area of a deflection roller 30 and fed to the first drying cylinder 34 of a drying section. It is understood that the roller 30 can also be arranged directly next to the press roller 24, whereby it can form a press nip with it or not.

As can be seen from Figure 1, the fibrous web 10 is guided around a suction roll 36 together with the top felt 14 following the first extended press nip S1 before it is removed from the roll 24

and fed to the second extended press nip S2. This results in a continuous closed web guide, up to the transfer of a drying section.

As can be seen in particular from the enlarged view of the central shoe press roller 20 in Figure 2, the central shoe press roller 20 comprises a hollow support 38 mounted in a rotationally fixed manner, a flexible press jacket 40 running around the hollow support 38 and two outer support devices 42 spaced apart from one another in the circumferential direction, by means of which the press jacket 40 is supported on the hollow support 38 in the region of the two extended press gaps S1 and S2.

The outer hollow beam 38 is assigned an inner beam 44, which is also mounted in a rotationally fixed manner, on which the hollow beam 38 is supported on the inside via a support device 46 in such a way that a resulting deflection generated by the differently directed pressing forces in the area of the two extended pressing gaps S1 and S2 is at least substantially compensated.

The inner support device 46 arranged between the hollow support 38 and the inner support 44 comprises at least one row of support elements 48 extending transversely to the web running direction L (see also Figure 3). The two outer support devices 46 each have at least one press shoe 50 and also several support elements 52 arranged in a row extending transversely to the web running direction L. As can be seen from Figures 1 to 3, each of the support elements 48 and 52 in the present case comprises at least one cylinder/piston unit.

The effective direction of the inner support device 46 lies in the resulting effective direction of the two outer support devices 42.

In the present embodiment, the support forces applied by the two outer support devices 42 are at least substantially equal. The radial directions of action of the two outer support devices 42 are offset by approximately 120°. The direction of action of the inner support device 46 lies in the bisector between the two radial directions of action of the two outer support devices 42 (see in particular Figure 2). In Figure 3, the inner support device 46 is aligned radially with one of the two outer support devices 42 for the sake of simplicity. In fact, however, the two support devices 42, 46 are offset from one another by 30° in the circumferential direction.

In the present embodiment, the forces applied by the two outer support devices 42 and the inner support device 46 are at least substantially equal, so that they form an equilateral triangle of forces. For this purpose, the rows of support elements of the two outer support devices 42 and the inner support device 46 have the same pitch. In addition, their support elements 52, 48 have the same piston surfaces.

As can be seen in particular from Figure 1, the two outer support devices 42 and the inner support device 46 can be subjected to the same, preferably variably adjustable, pressure P.

The forces applied by the three support devices 42, 46 are therefore in equilibrium.

As shown in Figure 1 by dashed lines, the support devices 54 and 56 provided for the internal support of the counter rolls 22, 24 can also be subjected to the pressure P.

As can be seen in particular from Figure 2, between the hollow support 38 and the press jacket 40, jacket guide strips 58 are also provided, by means of which the press jacket 40 is guided accordingly in the areas located in the circumferential direction between the press shoes 50.

The hollow support 38 and the inner support 44 are supported at their ends in lateral supports or stands 60 equidistant from one another. The bearings of the central shoe press roller 20 and the two counter rollers 22 and 24 on both sides are each located in a common plane.

As can be seen from Figure 1, a steam blower box 99 or another heating unit can be provided on the deflection roller 36, which is preferably designed as a suction roller, in order to increase the dewatering performance in the second press nip S2 and in the third press nip S3.

In the embodiment of a shoe press roller 20 shown in Figure 3, bearing bushes 62 are pushed onto the two ends of the inner support, which have a spherical outer bearing surface and are accommodated in a correspondingly designed receptacle of the respective stand 60. The joint bearings formed hereby ensure that the ends

the inner support 44 can be tilted relative to the hollow support 38 which is fixedly mounted on the uprights 60, so that the inner support 44 can be freely bent.

Figure 4 shows an alternative bearing arrangement in which a corresponding bearing bush 62' is pushed onto an axially inwardly extending projection 64 of the respective stator 60 and interacts with its spherical outer bearing surface with a correspondingly designed radially inner annular groove-like receptacle at the respective end of the hollow support 38, which is received together with the respective bearing bush 62' in an axially inwardly open annular groove 66 of the respective stator 60. For the sake of simplicity, only the right-hand end of the roller is shown in Figure 4. The bearing arrangement at the left-hand end of the roller is designed accordingly.

By using such a shoe press roller 20 as a central roller arranged between the two counter rollers 22 and 24, the deflection of the hollow beam 38 is influenced by the inner support device 46 in such a way that a deflection generated by the forces in the area of the two press gaps S1 and S2 is at least substantially compensated. The hollow beam 38 is therefore no longer subjected to bending, but only to shell deformation.

Figure 5 shows a schematic, partially sectioned representation of a further embodiment of a press arrangement. This embodiment differs from that of Figure 1 in that the press jacket 40 of the central shoe press roll 20, viewed in the roll cross-sectional plane, is arranged in the manner shown relative to the hollow

carrier 38 is guided offset, which allows for larger shoe widths. In addition, in the present case the lower counter roller 22 is also formed by a shoe press roller. As can be seen from Figure 5, in the present case a flat first press nip Sl is also provided, so that a straight felt and web passage results in the area of this press nip Sl.

In addition, the counter roll 24 is assigned a further shoe press roll 68, with which it forms a third extended press nip S3 located behind the extended press nip S2 in the web travel direction L. The support devices assigned to the press shoes of the two shoe press rolls 22 and 68 can be subjected to the same pressure P in the manner shown. The counter roll 24 can be formed by a solid roll, for example.

In Figure 5, the offset of the press jacket 40 relative to the press plane of the press gap S1 is indicated by al and its offset relative to the press plane of the press gap S2 is indicated by a2. The press jacket of the lower shoe press roll 22 is offset relative to the yoke assigned to this roll by the value al. In addition, the press jacket of the upper shoe press roll 68 is also offset relative to the relevant yoke, namely by the amount a3.

Otherwise, this embodiment according to Figure 5 has at least essentially the same structure as that of Figure 1. In both cases, a continuously closed web guide is provided. In addition, both the central shoe press roller 20 and the lower counter roller 22 are each blind-drilled and/or grooved in order to facilitate drainage.

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drainage of the two press nips S1 and S2 by spinning water into respective channels 72, 74 and 76. As can be seen from Figures 1 and 5, such drainage takes place on both sides following the first extended press nip S1 by spinning water away, for which purpose the channels 72 and 74 arranged on different sides are provided. In contrast, the channel 76 serves to drain the second extended press nip S2. The drainage to be achieved via the felts can therefore be correspondingly less. In order to support the spinning of water from the press jacket 40 of the shoe press roll 20, the press jacket 40 is guided in a polygonal manner between the two extended press nips S1 and S2 in the embodiments shown.

Figure 6 shows the pressure curve in the web travel direction L over the two press nips S1 and S2 of the embodiment according to Figure 1 or the press nips Sl to S3 of the embodiment according to Figure 5, with the pressure ρ being shown in the diagram against time or distance. The pressure profiles can be adjusted using the selected shoe widths 11 and 12 or 11 to 13 (see Figure 5). The pressure can increase continuously over the two or three consecutive extended press nips in the web travel direction L, which brings with it a continuous increase in the press performance.

Figure 7 shows a schematic, partially sectioned representation of a further press arrangement with an alternative embodiment of a central shoe press roller 78. In accordance with the press arrangement shown in Figure 1, the central shoe press roller 78 also forms in the present case with two deflection compensation rollers.

The counter rolls 22 and 24 again form two press nips Sl and S2 which are extended in the web travel direction L and which are also at least partially dewatered by spinning off water in channels 72, 74 and 76.
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As can be seen in particular from Figures 8 and 9, the central shoe press roller 78 comprises an outer hollow support 80 secured at its ends against twisting, a flexible press jacket 82 running around the hollow support 80 and two support devices 84 by which the press jacket 82 is supported on the inside in the area of the two press gaps S1 and S2.

An inner support 86, which is also mounted in a rotationally fixed manner, is assigned to the outer hollow support 80 that guides the press jacket 82. The press jacket 82 is supported directly on the inner support 86 by means of the two support devices 84 through the jacket of the hollow support 80.

The two support devices 84 each comprise at least one press shoe 88 guided on the outer hollow support 80 and several support elements 90 arranged in a row transverse to the web travel direction L, by means of which the press shoe 88 is supported directly on the inner support 86. The support elements 90 have radially inner pistons 92 guided on or in the inner support 86. At the radially outer end, these support elements 90 are coupled to the press shoe 88 via a respective joint. The support forces applied by the two support devices 84 are preferably variable and can be adjusted separately, for example, by means of a Delta-P valve 94 (see in particular Figure 7). In the present

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In this case, no further support device is provided apart from the two support devices 84.

The hollow beam 80 and the inner beam 86 are again equidistantly supported at their ends.

To assist in the spinning off of water, the press jacket 40 can again be guided in a polygonal manner, particularly between the two extended press nips Sl and S2.

In other respects, this press arrangement shown in Figure 7 has a structure that is at least essentially comparable to that of Figure 1. In particular, a closed web guide is also provided. For this purpose, it is basically possible to feed the fibrous web 10 to the drying section following the second extended press nip S2 in accordance with the design according to Figure 1 via the outer circumference of the counter roll 24 and via an offset press comprising the two rolls 26 and 28 (see Figure 1).

However, an additional, alternative web guide is shown in Figure 7. The fibrous web 10 is guided between the two extended press nips S1 and S2 formed with the shoe press roll 78, first around a deflection roll 36 designed as a suction roll (see also Figure 1). Unlike in the embodiment according to Figure 1, however, in the present case a transfer felt or belt 96 is guided through the second extended press nip S2 formed with the shoe press roll 78, viewed in the web travel direction L, with which the fibrous web 10 is finally connected to the second extended press nip S2.

is guided to the drying section via a deflection roller 98 designed as a suction roller, of which only the first drying cylinder 34 is shown in Figure 7.

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List of reference symbols

10 Fibrous web 12 ' Suction roll 14 Upper felt 16 Sieve belt 18 Underfelt 20 central shoe press roll 22 Counter roller 24 Counter roller 26 roller 28 roller 30 Deflection roller 32 Dry sieve 34 Drying cylinder 36 Suction roll 38 Hollow beam 40 Press jacket 42 external support structures 44 Inner carrier 46 internal support device 48 Support elements 50 Press shoe

52 Support elements 54 Support device 56 Support device 58 Sheath guide rails 60 Stand 62 Bearing bushes 62' Bearing bushes 64 axial approach 66 Ring groove 68 Shoe press roll 70 yoke 72 gutter 74 gutter 76 gutter 78 Shoe press roll 80 outer hollow beam 82 Press jacket 84 Support facilities 86 Inner carrier 88 Press shoe 90 Support elements 92 Pistons 94 Valve 96 Transfer felt or tape 98 Deflection suction roll 99 Steam blower box or heating unit

L Web direction P Pressure Sl extended press gap S2 extended press gap S3 extended press gap o Offset a2 Offset a3 Offset P Pressure

Claims (56)

Voith Sulzer Paper Technology S 6842 - Ku/Ho Patent GmbH &Igr;&psgr; nclaims 1. Press roll (20) for treating a fibrous web (10), such as in particular a paper or cardboard web, in at least one press nip (S1, S2) formed together with a respective counter surface, with a rotationally fixed carrier (38), a press jacket (40) running around the carrier (38) and at least one support device (42) arranged between the carrier (38) and the press jacket (40), via which the press jacket (40) is supported on the carrier (38) in the region of a respective press nip (S1, S2), characterized in that means (44, 46) are provided for influencing the deflection of the carrier (38). 2. Press roll according to claim 1, characterized in that the deflection of the carrier (38) can be influenced by the relevant means (44, 46) in such a way that a deflection generated by the forces in the region of the press nip(s) (S1, S2) is at least substantially compensated. 3. Press roll according to claim 2, characterized in that it comprises at least two circumferentially spaced apart other supporting devices (42) via which the press jacket (40) is supported on the carrier (38) in order to form at least two press gaps (S1, S2) with respective counter surfaces, and that the deflection of the carrier (38) can be influenced by the relevant means (44, 46) in such a way that a resulting deflection generated by the differently directed pressing forces is at least substantially compensated. 4. Press roll according to one of the preceding claims, characterized in that a bimetallic carrier is provided and the means for influencing the deflection comprise means for heating the carrier. 5. Press roll according to one of the preceding claims, characterized in that a slotted carrier is provided and the means for influencing the deflection comprise means for bracing the slotted carrier. 6. Press roll according to one of the preceding claims, characterized in that at least one inner (44) and/or at least one outer auxiliary support is assigned to the support (38) and the means (44, 46) for influencing the deflection comprise means (46) for mutual radial bracing of these supports (38, 44). ··»· ♦♦ 7. Press roll according to one of the preceding claims, characterized in that the carrier is provided as an outer hollow carrier (38) to which a rotationally fixed inner carrier (44) is assigned, and that the means (44, 46) for influencing the deflection comprise means (46) for mutual radial bracing of the hollow carrier (38) and the associated inner carrier (44). 8. Press roll according to one of the preceding claims, characterized in that the respective clamping is carried out hydraulically, pneumatically, mechanically, thermally and/or electromagnetically. 9. Press roller according to claim 7 and 8, characterized in that the means (44, 46) for influencing the deflection comprise at least one support device (46) arranged between the hollow support (38) and the inner support (44). 10. Press roll according to claim 9, characterized, that the support device (46) arranged between the hollow support (38) and the inner support (44) comprises at least one row of support elements (48) extending transversely to the web running direction (L). 25 11. Press roll according to one of the preceding claims, characterized in that the hollow beam (38) and the inner beam (44) are equidistantly mounted at their ends.
5 12. Press roll according to one of the preceding claims, characterized in that it has a flexible press sleeve (40) and is designed as a shoe press roll (20).
10 13. Press roll according to one of the preceding claims, characterized in that at least one support device (42) arranged between the carrier (38) and the press jacket (40) comprises at least one press shoe (50) and a plurality of support elements (52) arranged in a row extending transversely to the web running direction (L). 14. Press roller according to one of the preceding claims, characterized in that the support elements (48, 52) each comprise at least one cylinder/piston unit. 15. Press roll according to one of the preceding claims, characterized in that it comprises two outer support devices (42) which are spaced apart from one another in the circumferential direction and are arranged between the hollow support (38) and the press cover (40), by means of which the press cover (40) can be supported in the region of two counter surfaces to be formed is supported on the hollow support (38), and comprises at least one inner support device (46) arranged between the hollow support (38) and the inner support (44), by means of which the deflection of the hollow support (38) can be influenced such that a resulting deflection of the hollow support (38) generated by the differently directed pressing forces is at least substantially compensated. 16. Press roll according to claim 15,
characterized in that the effective direction of the inner support device (46) lies in the resulting effective direction of the two outer support devices (42). 17. Press roll according to claim 15 or 16, characterized in that at least the two outer support devices (42) applied supporting forces are at least substantially equal are large. 18. Press roll according to one of the preceding claims, characterized in that the radial effective directions of the two outer support devices (42) are offset by approximately 120°.
25 19. Press roll according to claim 18, characterized in that the forces applied by the two outer support devices (42) and the inner support device (46) are at least substantially equal and form an equilateral triangle of forces. 20. Press roll according to one of the preceding claims, characterized in that the support element rows of the two outer support devices (42) and the inner support device (46) have the same pitch and their support elements (52, 48) have the same piston areas. 21. Press roll according to one of claims 1 to 18, characterized in that the forces applied by the two outer support devices (42) are at least substantially equal and form an isosceles triangle of forces with the force applied by the inner support device (46). 22. Press roll according to claim 21, characterized in that the support element rows of the two outer support devices (42) have the same pitch and their support elements (52) have the same piston areas. 23. Press roll according to claim 21 or 22,
characterized in that the total piston area of the inner support device (46) is adapted accordingly to generate a force which at least substantially compensates for the resulting force of the two outer support devices (42). 24. Press roll according to claim 23, characterized in that the individual piston surfaces of the support elements (48) of the inner support device (46) are of the same size as the individual piston surfaces of the support elements (S2) of the two outer support devices (42) and that the total piston surface of the inner support device (46) is adapted accordingly via the number of support elements (48). 25. Press roller according to one of the preceding claims, characterized in that the piston pitch of the inner support device (46) is equal to that of the two outer support devices (42) and that the total piston area of the inner support device (46) is adapted accordingly via the size of the individual piston areas. 26. Press roll according to one of the preceding claims, characterized in that the effective direction of the inner support device (46) lies in the bisector between the two radial effective directions of the two outer support devices (42). 27. Press roll according to one of claims 1 to 18, characterized in that the forces applied by the two outer support devices (42) are of different magnitude and form a unequal-sided triangle of forces with the force applied by the inner support device (46). 28. Press roll according to claim 27, characterized in that the support element rows of the two outer support devices (42) have an unequal division and/or their support elements (52) have piston surfaces of different sizes. 29. Press roll according to claim 27 or 28, characterized in that the total piston area of the inner support device (46) is adapted accordingly to generate a force which at least substantially compensates for the resulting force of the two outer support devices (42). 30. Press roll according to one of claims 27 to 29, characterized in that the two outer support devices (42) each comprise at least one press shoe (50) and that the press shoes (50) have an equal width extending in the web running direction (L). 31. Press roll according to one of the preceding claims, characterized in that the two outer support devices (42) and the inner support device (46) can be acted upon by the same, preferably variably adjustable, pressure (P). 32. Press roll according to one of the preceding claims, characterized in that the forces applied by the two outer support devices (42) and the inner support device (46) are kept in equilibrium via the individual pressures acting on the support elements (52, 48). 33. Press roller according to one of the preceding claims, characterized in that the press jacket (40) is offset relative to the hollow carrier (38) when viewed in the cross-sectional plane of the roller. 34. Press roll (78) for treating a fibrous web (10), in particular a paper or cardboard web, in at least one press nip (S1, S2) formed with a respective counter surface, with a support (80) secured against twisting at its ends, a press jacket (82) running around the support (80) and at least one support device (84) by which the press jacket (82) is supported on the inside in the region of a respective press nip (S1, S2), characterized in that an outer hollow support (80) guiding the press jacket (82) and an inner support (86) are provided and that the press jacket (82) 10 is supported directly on the inner support (86) by means of a respective support device (84) through the hollow support casing (80). 35. Press roll according to claim 34, characterized in that the support device (84) comprises at least one press shoe (88) guided on the hollow support (80) and at least one support element (90) by which the press shoe (88) is supported directly on the inner support (86), the press jacket (82) preferably being flexible. 36. Press roll according to claim 35, characterized in that the support element (90) is coupled to the press shoe (88) via a joint. 37. Press roll according to one of claims 34 to 36, characterized in that the supporting force applied by the supporting device (84) is variably adjustable. 38. Press roll according to one of claims 34 to 37, characterized in that the hollow support (80) and the inner support (86) are mounted equidistantly at their ends. 39. Press roll according to one of claims 34 to 38, characterized in that at least two support devices (84) are provided in order to support the press jacket (82) in the region of at least two press gaps (S1, S2) which are spaced apart from one another in the circumferential direction. 40. Press roll according to claim 39, characterized in that the supporting forces applied by the various supporting devices (84) are separately adjustable. 41. Press roll according to one of claims 1 to 40, characterized in that the press jacket (40) is guided in a polygonal manner at least in sections, preferably at least between the two extended press nips (S1, S2). 42. Press roller according to one of claims 1 to 41, characterized in that the press casing (40) is blind-drilled and/or grooved. 43. Press arrangement for treating a fibrous web (10), in particular a paper or cardboard web, with at least one press roll (20, 78) according to one of the preceding claims, characterized in that the shoe press roll (20, 78) is provided with a flexible press cover (40, 82) formed press roll is provided as a central roll between two further press rolls (22, 24) in order to form with these a press nip (S 1, S2) extended in the web running direction (L).
5 44. Press arrangement according to claim 43, characterized in that it has a continuously closed track guide. 45. Press arrangement according to claim 43 or 44, characterized in that a felt (14) is guided through both extended press nips (S1, S2). 46. Press arrangement according to one of the preceding claims, characterized in that a felt (14) guided at least through the first, preferably through both extended press nips (S1, S2) is simultaneously provided as a pickup felt. 47. Press arrangement according to one of the preceding claims, characterized in that the fibrous web (10) is guided between the two extended press nips (S1, S2) formed with the shoe press roll (20, 78), preferably together with a felt, around a deflection roll (36) preferably designed as a suction roll. 13 48. Press arrangement according to one of the preceding claims, characterized in that a transfer felt or belt (96) is guided through the second extended press nip (S2) formed with the shoe press roll (78) as viewed in the web travel direction (L), and that the fibrous web (10) following the second extended press nip (S2) together with this transfer felt or belt (96) is preferably guided to a subsequent drying section via a deflection roller (98) preferably designed as a suction roller. 10 49. Press arrangement according to one of the preceding claims, characterized in that at least one extended press nip (S1, S2) is doubly felted. 50. Press arrangement according to claim 49, characterized in that both extended press nips (S1, S2) are doubly felted. 51. Press arrangement according to one of the preceding claims, characterized in that the press shell (40, 82) of the shoe press roll (78) and/or at least one of the press rolls (22) forming an extended press gap (S1) with the shoe press roll (78) is blind-drilled and/or grooved.
25 52. Press arrangement according to claim 51, characterized in that the dewatering of at least one extended press nip (Sl, S2) is carried out at least partially by throwing water into at least one channel (72, 74, 76) or the like. 53. Press arrangement according to one of the preceding claims, characterized in that the further press roller (24) forming the second extended press nip (S2) with the central roller (20) as viewed in the web travel direction (L) forms a third press nip (S3) together with an additional roller (26, 68).
10 54. Press arrangement according to claim 53,
characterized, that the additional roller (68) is a shoe press roller and that the third press nip (S3) is extended in the web travel direction (L). 15 55. Press arrangement according to one of the preceding claims, characterized in that the further press roller (24) forming the second extended press nip (S2) with the central roller (20) in the web running direction (L) can be heated in order to facilitate the dewatering of the fibrous web (10) in the second press nip (S2) and optionally the third press nip (S3) and to support the easier release of the fibrous web (10) from the further press roll (24). 56. Press arrangement according to one of the preceding claims, characterized in that a steam blower box (99) or another heating unit is provided on the deflection roller (36), which is preferably designed as a suction roller. in order to increase the dewatering performance in the second press nip (S2) and, if necessary, in the third press nip (S3).