EP1063351B1 - Soft roll and process for making such a roll - Google Patents

Description

The present invention relates to a roller, in particular for smoothing of paper webs, with a hard one consisting in particular of metal Roll core with an elastic matrix material on the outside comprehensive elastic reference layer is provided. Farther The invention relates to a method for producing such a roller directed.

Elastic rollers of this type are used, for example, when satinizing paper webs. An elastic roller forms a press nip with a hard roller through which the paper web to be processed is passed. While the hard roller has a very smooth surface, for example made of steel or cast iron, and is responsible for smoothing the side of the paper web facing it, the elastic roller acting on the opposite side of the paper web causes the paper web to be leveled and compressed in the press nip. The size of the rollers is 3 to 12 m in length and 450 to 1500 mm in diameter. They withstand line forces up to 600 N / mm and compressive stresses up to 130 N / mm ² .

Since the tendency in papermaking is that the satin in Online operation takes place, i.e. that the the paper machine or coating machine leaving paper web directly through the paper smoothing device (Calender) is guided to the rollers of the smoothing device higher requirements, particularly with regard to temperature resistance than previously posed. Due to the high required in online operation Transport speeds of the paper web and the associated high rotational speeds of the calender rolls, their nip frequency, that is the frequency at which the reference compresses and again is relieved, increased, which in turn leads to increased roller temperatures leads. These high temperatures, which arise in online operation, lead to problems with known elastic rollers until destruction of the plastic covering. On the one hand are known Plastic coverings maximum temperature differences of about 20 ° C over the Width of the roller permitted and on the other hand have that for the coating Usually plastics used are much higher Thermal expansion coefficients than those commonly used Steel rollers or chill cast rollers, so that by an increase in temperature high axial tensions between the steel roller or chilled iron roller and the associated plastic coating occur.

Due to these high voltages associated with particular points occurring heating points within the plastic coating So-called hot spots can occur, at which a detachment or even the plastic layer bursts open.

These hot spots occur particularly when in addition to mechanical stresses and the relatively high temperature crystallization points in the form of, for example, faulty bonds, deposits or above-average indentations of the elastic covering, for example due to folds or foreign bodies on the paper web, available. In these cases, the temperature at these crystallization points rise from the usual 80 ° C to 90 ° C to over 150 ° C, whereby the aforementioned destruction of the plastic layer takes place.

It is an object of the invention to provide a roller of the type mentioned To be trained so that the risk of hot spots is reduced becomes. Furthermore, a method for producing such a roller is to be specified become.

The part of the task relating to the roller is based on the invention solved by a roller of the type mentioned in that the elastic cover layer rotatably but longitudinally displaceable on the roller core is arranged. A corresponding method according to the invention is characterized in that the elastic reference layer is longitudinally displaceable but is rotatably applied to the roll core.

Characterized in that the elastic reference layer according to the invention is longitudinally displaceable is arranged on the roll core, it is achieved that also at heating of the elastic roller, for example in operation, none Longitudinal stresses between the roll core and the elastic reference layer occur. When heated appropriately, the elastic stretches Reference layer in the longitudinal direction due to the higher coefficient of thermal expansion more out than the roll core, which is due to the longitudinal displaceability of the reference layer only leads to the fact that a relative movement between the elastic reference layer and the Roll core takes place in the axial direction. Either the both ends of the elastic reference layer in opposite directions move axially relative to the roll core or there may be a asymmetrical longitudinal displacement of the elastic reference layer the roller core. Depending on the different coefficients of thermal expansion and the temperatures that occur the relative shift between the reference layer and the roll core for example about 5 to 50 mm, usually 10 to 20 mm.

In the case of a roller designed according to the invention, there is therefore between the elastic reference layer and the roller core a tension-free connection before, which leads to a reduction of hot spots and at the one In principle, the reference layer is not detached from the roller core is possible.

Due to the non-rotatable arrangement of the elastic reference layer on the Roller core ensures that the reference layer is securely together during operation is rotated with the roller core as a unit, so that a uniform quality of the web to be smoothed is guaranteed.

According to an advantageous embodiment of the invention, the elastic Reference layer free of play, in particular arranged in a press fit on the roll core. It is preferred between the elastic reference layer and a separation layer for the roller core, in particular to reduce friction provided between the elastic reference layer and the roll core. This separating layer can advantageously consist of silicone and / or from an essentially monomolecular layer and / or consist of a corrosion-inhibiting or -preventing material.

Thanks to the elastic reference layer, which is arranged without play, in particular in a press fit it is ensured that in smoothing mode even with a relative high mechanical stress on the reference layer over its entire Extends form-fittingly on the surface of the roller core. An upset or, for example, wrinkling in the reference layer, which lead to a reduction in the quality of the material web being treated would be prevented. Through the interface becomes one the friction between the elastic reference layer and the roll core reduced so that when the roller is heated the desired Longitudinal displacement between the reference layer and the roll core take place can. The thinner the separating layer, the firmer is the seat of the reference layer on the roll core.

Because of the longitudinally displaceable mounting of the elastic reference layer on the roller core it is basically possible that moisture penetrate between the elastic reference layer and the roller core and this causes corrosion on the metallic roll core can, the separating layer is advantageously made of a corrosion-inhibiting or contraceptive material.

The rotation lock and simultaneous displaceability of the elastic cover layer on the roll core is advantageous by on the surface of the roll core provided anti-rotation and guide elements and by interacting with them on the elastic reference layer provided counter elements reached. For example, in and / or on the elastic reference layer, in particular in and / or on the radially inner surface of the elastic reference layer or more extending substantially in the axial direction Longitudinal guides can be provided in the on the surface of the roll core engage provided, in particular bolt-shaped engagement elements. In the same way, the longitudinal guides on the roller core and the engaging members are provided on the elastic reference layer his.

Due to the slot-shaped longitudinal guides in particular and in these engaging bolt-shaped engagement elements is a simple rotation lock with simultaneous longitudinal displaceability of the elastic reference layer possible on the roll core. Basically, however, are also other configurations with which a rotation lock with simultaneous Longitudinal displaceability is possible.

According to a further preferred embodiment of the invention, in the matrix material of the elastic reference layer one or more fiber layers embedded. Depending on the fiber material, the Embedding the fiber layers the physical properties of the elastic Reference layer can be specified. For example, by embedding of fibers with a stiffness that is higher than the stiffness of the Matrix material, the overall rigidity of the elastic reference layer increases become. Furthermore, the thermal conductivity of the elastic reference layer when choosing fibers with a high thermal conductivity a reference layer made of pure matrix material significantly improved become. This is particularly true with regard to the removal of excess Heat beneficial.

The fiber layers are preferably at least partially inclined Surface of the roll core extending fiber bundle formed, being in particular include crossing fiber bundles. By crossing each other A bundle of fibers is created through which one Torsion of the elastic reference layer is largely avoided. Since the elastic reference layer in a roller designed according to the invention is not firmly attached to the surface of the roll core, is fundamental a torsion of the freely displaceable reference layer is conceivable. Therefore the elastic reference layer is constructed according to the invention so that counteracting torsion of the reference layer.

The elastic reference layer can be a radially outer functional layer and a radially inner connection layer for connection include the functional layer with the roller core. By dividing up in two sub-layers, these can each optimally match their respective Tasks to be adjusted. For example, the radially outer one Functional layer have a higher elasticity than the radially inner layer Link layer, while this in turn, for example has a higher rigidity to the rotation lock with the roller core to be able to reliably meet.

The fiber content of the reference layer can advantageously be radially from the inside out vary outside, in particular decrease, preferably in the radially outer Area of the reference layer of fiber content essentially is zero.

By varying the fiber content of the reference layer radially from the inside outwardly it is achieved that the reference layer has a coefficient of thermal expansion has, which also in accordance with the fiber content radial direction is different from the inside to the outside. Because usually the matrix material has a significantly higher coefficient of thermal expansion has as the fiber material used, is therefore the respective resulting coefficient of thermal expansion of the interspersed with fibers Matrix material both from the coefficient of thermal expansion of the Matrix material as well as that of the fibers. The more fibers in embedded in the matrix material, the more the resulting one looks the same Coefficient of thermal expansion is the coefficient of thermal expansion of the fibers used. In this way it is possible to reduce the coefficient of thermal expansion the radially inner region of the reference layer by a relatively high fiber content so that it is in the same order of magnitude as the coefficient of thermal expansion of the roll core. If the roller heats up during operation the radially inner region of the reference layer is thus only slightly more than the roll core, so that a relatively small relative displacement between the elastic reference layer and the roll core arises.

Because the fiber content is high, the stiffness of the cover layer is also clear increased, must be in the radially outer areas of the reference layer the fiber content should be chosen lower, otherwise the surface the roller is too hard and would not be suitable for calendering. Through a in particular essentially continuously decreasing radially outwards Fiber content within the reference layer is achieved in that when the roller is heated, those occurring within the reference layer Longitudinal stresses due to the different thermal expansions of the different areas of the reference layer never become so large that a detachment or destruction of the reference layer arises.

According to the invention, the elastic roller is used to produce an elastic roller Cover layer is longitudinally displaceable but non-rotatable on the roller core applied. For example, the elastic reference layer on the Roll core are shrunk so that a shrink fit the elastic reference layer is reached on the roll core.

This can be done before applying the elastic reference layer on the roll core a separating layer, especially for reducing friction between the reference layer and the roller core.

In principle, however, any method is possible with which the elastic Reference layer rotatably but longitudinally displaceable, in particular free of play the roller core can be applied. For example, it is fundamental also possible to have a prefabricated, tubular reference layer to postpone the roll core.

If the separating layer is designed, for example, so that it forms a firm connection, for example an adhesive bond between the matrix material and prevents the roll core, for example, for production the reference layer contains a large number of fibers, in particular in several fiber layers one above the other, can be wound up on the roll core. More like that It is possible to fashion the fibers in a particularly cylindrical manner Winding bobbin out after the end of the winding process the wound reference layer is pulled out.

The fibers can each be in the form of one or more fiber bundles and / or fiber rovings and / or nonwoven fabrics are wound. It is it is advantageous that the fibers be wound up with the matrix material be surrounded, especially by a matrix bath. In principle, however, it is also possible that the fibers essentially be wound up dry and during or after winding up with acted upon the matrix material, in particular completely into the matrix material be embedded.

Further advantageous embodiments of the invention are in the subclaims specified.

Fig. 1

eine teilweise aufgebrochen dargestellte Seitenansicht einer erfindungsgemäßen ausgebildeten Walze und

Fig. 2

einen Teilquerschnitt durch die erfindungsgemäß ausgebildete Walze gemäß Fig. 1.

The invention is described below using an exemplary embodiment with reference to the drawing; in this show:

Fig. 1

a partially broken side view of a roller according to the invention and

Fig. 2

2 shows a partial cross section through the roller designed according to the invention according to FIG. 1.

The roller according to the invention shown in Fig. 1 comprises a roller core 1, on the outside of which an elastic reference layer 2 is provided is.

As in the middle, partially torn area of the reference layer 2 can be seen, this consists of a variety of, for example fiber bundles consisting of carbon, glass or aramid fibers 3, which are essentially parallel in one layer and in one next layer are wound obliquely on the roll core 1. The Reference layer 2 can consist of a large number of such through the fiber bundle 3 formed fiber layers 4 (Fig. 2), for example between 10 and 50 fiber layers 4, be formed.

The fiber layers 4 are embedded in an elastic matrix material 5 (FIG. 2) and together with this form the elastic reference layer 2. Due to the elastic matrix material 5, the reference layer 2 receives its required Elasticity, the fiber bundle 3 has the required rigidity generate the reference layer 2.

At the front ends 6, 7 of the elastic reference layer 2 are slot-shaped longitudinal recesses 8, 9 formed, the longitudinal recesses 8, as indicated by the torn illustration, not through the entire thickness of the elastic reference layer 2 extend, but, as can be seen from Fig. 2, only as Depressions formed on the inside of the elastic reference layer 2 are. However, the longitudinal recesses 8, 9 can also extend the entire thickness of the elastic reference layer 2, as exemplified by the longitudinal recesses 9 in FIG. 1 is.

Furthermore, there is both a laterally open design of the longitudinal recesses 8 as well as a laterally closed design of the longitudinal recesses 9 possible.

Bolt-shaped engagement elements engage in the longitudinal recesses 8, 9 10, which are formed on the surface of the roll core 1. The bolt-shaped Engagement elements 10 have a diameter that essentially that existing in the circumferential direction of the reference layer 2 clear width of the longitudinal recesses 8, 9 corresponds. Thus at in the longitudinal recesses 8, 9 arranged bolt-shaped engagement elements 10 a twisting of the elastic reference layer 2 on the Roll core 1 prevented.

Due to the elongated, axially oriented design the longitudinal recesses 8, 9, however, is a longitudinal displacement of the elastic reference layer 2 on the roller core 1 in the direction of arrows 11, 12 possible, since in principle the elastic reference layer 2 is not glued, for example, but arranged freely movable on the roll core 1 is.

When the roller heats up, for example during operation, it expands elastic reference layer 2 due to its relative to the roll core 1 larger coefficients of thermal expansion in the axial direction more from as the roll core 1, so that the ends 6, 7 of the elastic reference layer 2 move in the direction of arrows 11, 12. A tension load between the roll core 1 and the elastic reference layer 2 therefore does not occur due to the different dimensions.

Due to the fiber bundle 3 arranged in the cross composite, despite the free storage of the elastic reference layer 2 on the roll core 1 torsion of the reference layer 2 is reliably prevented.

From Fig. 2 it can be seen that between the roll core 1 and the elastic Reference layer 2, a thin separating layer 13 may be arranged can, which consists for example of silicone. The interface can one have the function of a lubricant, so that the elastic reference layer 2 despite their press fit on the roll core 1 in axial Direction is slidable. Furthermore, the separating layer 13 can be made of corrosion-inhibiting or -preventive material, so that the Surface of the roll core 1 is protected against corrosion.

LIST OF REFERENCE NUMBERS

1

roll core

2

elastic cover layer

3

fiber bundles

4

fiber layers

5

elastic matrix material

6

front end

7

front end

8th

longitudinal recesses

9

longitudinal recesses

10

bolt-shaped engaging elements

11

arrow

12

arrow

13

Interface

Claims (13)

1. A roll, in particular for the smoothing of paper webs, having a hard roll core (1) consisting in particular of metal and being provided on its outside with an elastic covering layer (2) including an elastic matrix material (5),
   characterized in that the elastic covering layer (2) is rotationally fixedly, but longitudinally displaceably arranged on the roll core (1).
2. A roll in accordance with claim 1, characterized in that the elastic covering layer (2) is disposed free from play, in particular in force fit, on the roll core (1).
3. A roll in accordance with claim 1 or claim 2, characterized in that a separation layer (13) is provided between the elastic covering layer (2) and the roll core (1), in particular to reduce the friction between the elastic covering layer (2) and the roll core (1); in particular in that the separation layer (13) consists of silicone and/or of a substantially monomolecular layer, and/or of a corrosion-inhibiting or corrosion-preventing material.
4. A roll in accordance with any one of the preceding claims, characterized in that the coefficient of thermal expansion of the elastic covering layer (2) is greater than the coefficient of thermal expansion of the roll core (1).
5. A roll in accordance with any one of the preceding claims, characterized in that rotational fixation and guide elements (10) are provided on the surface of the roll core (1) which act together with counter-elements (8, 9) provided on the elastic covering layer (2) so that the elastic covering layer (2) is longitudinally displaceably, but rotationally fixedly fastened to the roll core (1); in particular in that one or more longitudinal guides (8, 9) extending essentially in an axial direction are provided in and/or on the elastic covering layer (2), in particular in and/or on the radially inwardly disposed surface of the elastic covering layer (2); and in that in particular pin-like engaging elements (10), which engage in the longitudinal guides (8, 9); are provided on the surface of the roll core (1), with the longitudinal guides preferably being provided on the roll core and the engaging elements being provided on the elastic covering layer.
6. A roll in accordance with any one of the preceding claims, characterized in that one or more fiber layers (4) are embedded in the matrix material (5) of the elastic covering layer (2); in particular in that the fiber layers (4) are formed at least partially by fiber bundles (3) running obliquely to the surface of the roll core (1) and particularly comprise crossed fiber bundles (3).
7. A roll in accordance with any one of the preceding claims, characterized in that the elastic covering layer (2) comprises a radially outer functional layer and a radially inner connection layer to connect the functional layer to the roll core (1); in particular in that the fiber content of the connection layer is higher than the fiber content of the functional layer; and/or in that the fiber content of the connection layer in its radially outer region is essentially equal in amount to the fiber content of the functional layer in its radially inner region.
8. A roll in accordance with claim 6 or claim 7, characterized in that the fiber content of the covering layer (2) varies, in particular decreases, going radially from the inside to the outside; and/or in that the fiber content in the radially outwardly disposed region of the covering layer (2) is substanially equal to zero; and/or in that the fibers of the fiber layers (4) are designed as glass and/or as carbon fibers.
9. A roll in accordance with any one of the preceding claims, characterized in that the matrix material (2) is a plastic, in particular a thermosetting plastic or a thermoplastic; and/or in that the matrix material (2) comprises a resin/hardener combination.
10. A method for the manufacture of an elastic roll having a hard roll core consisting in particular of metal and an elastic covering layer including an elastic matrix material, in particular for the manufacture of a roll in accordance with any one of the preceding claims, characterized in that the elastic covering layer is longitudinally displaceably but rotationally fixedly applied to the roll core.
11. A method in accordance with claim 10, characterized in that the elastic covering layer is shrunk onto the roll core; and/or in that, prior to the application of the elastic covering layer to the roll core, a separation layer is applied, in particular to reduce the friction between the elastic covering layer and the roll core.
12. A method in accordance with claim 10 or claim 11, characterized in that, to produce the covering layer, a plurality of fibers, in particular multiple fiber layers one over the other, is wound onto the roll core or onto a coil former, in particular a cylindrical coil former.
13. A method in accordance with claim 12, characterized in that the fibers are wound onto the roll core or onto a coil former, in particular onto a cylindrical coil former, in the form of one or more fiber bundles and/or fiber rovings and/or fiber fleeces, with a roving respectively including a plurality of adjacent fibers of the same kind; and/or
    in that the fibers are enveloped by the matrix material, in particular are drawn through a matrix bath, prior to the winding onto the roll core or onto a coil former, in particular onto a cylindrical coil former; or in that the fibers are wound onto the roll core or onto a coil former, in particular onto a cylindrical coil former in an essentially dry state and the matrix material is applied to them during or after winding, with the fibers being in particular completely embedded in the matrix material; and/or
    in that the fibers are wound onto the roll core or onto a coil former, in particular onto a cylindrical coil former obliquely, in particular in a crossed assembly; and/or
    in that glass and/or carbon fibers are used as the fibers.

Images