ROLLER

Abstract

The invention relates to a roller for producing a fibrous web, in particular a paper web including a rotationally symmetrical base body which is rotatable about a longitudinal axis and has a shell surface on which there are arranged at least two elastically deformable and/or deflectable ring-shaped lamellas which extend away from the shell surface in the radial direction and which surround the base body in the circumferential direction, wherein the lamellas are arranged at least in sections at an angle relative to a center plane of the roller aligned perpendicular to the longitudinal axis of the roller, thus forming an angle of inclination.

Claims

1. A roller for producing a fibrous web, in particular a paper web, the roller comprising: a rotationally symmetrical base body which is rotatable about a longitudinal axis; and a shell surface on which there are arranged at least two elastically deformable and/or deflectable ring-shaped or spiral lamellas which extend away from the shell surface in a radial direction, the lamellas surround the base body in a circumferential direction, wherein the lamellas are arranged at least in sections at an angle diagonally relative to a center plane of the roller, the center plane being aligned perpendicular to the longitudinal axis of the roller, thus forming the angle in the form of an angle of inclination.

2. The roller according to claim 1, wherein the lamellas are inclined toward the center plane of the roller.

3. The roller according to claim 1, wherein the at least two lamellas are arranged in a mirror-symmetrical manner with respect to the center plane of the roller.

4. The roller according to claim 1, wherein a radial extension of the lamellas is substantially equal.

5. The roller according to claim 1, wherein the angle of inclination of the lamellas varies in an axial direction of the roller, wherein the angle of inclination of the lamellas increases from an edge of the roller towards the center plane.

6. The roller according to claim 5, wherein the angle of inclination increases continuously towards the center plane.

7. The roller according to claim 5, wherein a distance between two adjacent connection points of the lamellas with the shell surface decreases in the axial direction towards the center plane of the roller.

8. The roller according to claim 1, wherein a diameter of the roller changes in a direction toward the center plane of the roller increases and/or an intermediate body is arranged between the shell surface of the roller and the lamellas having a diameter of which increases in the direction of the center plane of the roller.

9. The roller according to claim 8, wherein distances between adjacent connection points of the lamellas with the shell surface is substantially equal in the axial direction.

10. The roller according to claim 1, wherein the lamellas are manufactured of an elastic and/or compression-resistant material, the material being plastic or rubber.

11. The roller according to claim 1, wherein the lamellas are arranged on a roll cover which is fastened in a rotationally fixed manner on the shell surface of the roller.

12. The roller according to claim 11, wherein the roll cover and the lamellas are manufactured of the same material.

13. The roller according to claim 11, wherein radial outer ends of at least two adjacent lamellas are connected with an elastic membrane or that membrane at least in sections forms a continuous contact surface.

14. A roller arrangement, comprising: a roller according to claim 1; and a mating roll, wherein a distance between the rollers is variably adjustable.

15. The roller arrangement according to claim 14, wherein the mating roll is heated and/or has a shell surface with openings, in the form of a porous shell surface, wherein the openings connect the shell surface of the mating roll with an interior of the mating roll.

16. The roller arrangement according to claim 15, wherein the shell surface of the mating roll has a lower coefficient of friction than the outer surface of the roller.

17. The roller arrangement according to claim 14, wherein at least two rollers according to claim 1 are assigned to the mating roll which, together form a nip to receive the fibrous web.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:

[0038] FIG. 1 illustrates a longitudinal sectional view of an embodiment of a roller of the present invention;

[0039] FIG. 2 show details of the roll shown in FIG. 1;

[0040] FIG. 3 illustrates a longitudinal sectional view of another embodiment of a roller of the present invention;

[0041] FIG. 4 illustrates a cross-sectional view of a roll arrangement with a roller according to the present invention;

[0042] FIG. 5a shows details of the roller arrangement of FIG. 4, in a load-free condition;

[0043] FIG. 5b shows details of the roller arrangement of FIG. 4, in a loaded condition;

[0044] FIG. 6 illustrates, in a schematic manner, details of the roller arrangement of the roller of FIG. 1; and

[0045] FIG. 7 shows a cross sectional view of an embodiment of a roller arrangement with several rolls according to the present invention.

[0046] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0047] Referring now to the drawings, and more particularly to FIG. 1, there is shown a roller 10 according to a first embodiment of the present invention, with a detail of which being shown in FIG. 2. A second embodiment of roller 10 is shown in FIG. 3. FIGS. 4 and 7 each show different embodiments of a roller arrangement with roller 10 shown in FIG. 1 or 3. FIGS. 5 and 6 serve to explain the principle of operation of rollers 10 shown in FIG. 1 or 3.

[0048] Rolls 10 shown in the figures serve to produce a fibrous web 11 (FIG. 7), in particular a paper web 11, in which compression or stretching in a direction transverse to the longitudinal extension of fibrous web 11 is to be adjusted in a controlled manner. In the following, the design examples are described in connection with a transverse compression of fibrous web 11.

[0049] Each roller 10, shown in the figures, can be rotated about its longitudinal axis A and each roller 10 has a rotationally symmetrical base body 12 with a shell surface 14. A number of elastically deformable and deflectable ring-shaped lamellas 16 are arranged on shell surface 14 and are made of an elastic and compression-resistant material. For example, lamellas 16 can be made of plastic or rubber material.

[0050] In the illustrated design examples, lamellasl6 are attached to an intermediate body 18 (for example, designed integrally with or molded to the latter) located between base body 12 and lamellas 16. Moreover, lamellas 16 surround base body 12 in its circumferential direction. In principle, lamellas 16 can also extend directly, that is without an intermediate body 18, at an angle directed away from shell surface 14 of base body 12 and be inclined toward a center plane E of roll 10.

[0051] Rolls 10 are designed not only rotationally symmetrical with respect to their respective longitudinal axes A, but also mirror symmetrical with respect to center plane E. In particular, lamellas 16 are arranged mirror-symmetrically with respect to center plane E as well as inclined mirror-symmetrically in the direction of center plane E of roller 10. It is understood that lamellas 16 may also be mirror-symmetrically inclined away from center plane E of roll 10 to facilitate transverse stretching of fibrous web 11. Asymmetrical lamella arrangements and/or designs are also implemented in order to be able to generate the desired compression and/or respectively stretching profile.

[0052] To ensure that fibrous web 11 runs evenly onto roller 10, all lamellas 16 have a substantially equal radial extension, whereby an outer diameter of an unloaded roller 10 is substantially constant.

[0053] As can be seen from the design examples, shown in FIGS. 1 to 3, radial outer ends of lamellas 16 are connected to a flexible membrane 20 to form a continuous contact surface for fibrous web 11. At this point, it should be noted that the conveying of fibrous web 11 is also possible without membrane 20, in other words, by direct placement of fibrous web 11 on lamellas 16. In principle, lamellas 16 connected to an elastic membrane 20 have a higher coefficient of friction than free-standing lamellas 16. To further increase the coefficient of friction, membrane 20 may also be textured.

[0054] Together with lamellas 16 and diaphragm 20, intermediate body 18 forms a roll cover which is secured in a rotationally fixed manner on shell surface 14 of roll 10. Lamellas 16 and intermediate body 18 as well as diaphragm 20 can thereby be made of the same material.

[0055] Lamellas 16, intermediate body 18 and/or diaphragm 20 can also be manufactured of different materials to ensure individual adaptability to the specific requirements.

[0056] Roll 10 according to a first embodiment is described below with reference to FIGS. 1 and 2.

[0057] Roller 10 according to the first embodiment includes a number of lamellas 16, whose angles N1 of inclination vary in an axial direction of roll 10. In FIG. 2, angle N1 is drawn with respect to a plane E, which is parallel to plane E.

[0058] Angles of inclination N1 between lamellas 16 and center plane E increase continuously from edges 22 limiting roller 10 in the axial direction towards center plane E. Such an alignment of lamellas 16 results in angles N2 between lamellas 16 and shell surface 14 decreasing continuously in the direction towards center plane E. This ensures that, when a force acting perpendicularly to longitudinal axis A of roll 10 is applied, a lamella 16 positioned in a more upright manner relative to shell surface 14 is deflected more strongly in a direction parallel to longitudinal axis A of roll 10 than a lamella 16 inclined more flatly to shell surface 14, as will be explained in more detail below (FIG. 6). With the reference system applied in FIGS. 4 to 6, this means that when a force acting in the radial direction of roller 10 (=y-direction) is applied, lamella 16, shown on the left-hand side, which is inclined in a more upright manner relative to shell surface 14, is deflected more strongly in a direction parallel to longitudinal axis A of roller 10 than lamella 16 shown on the right-hand side, which is inclined more flatly relative to shell surface 14, as will be explained in more detail below.

[0059] The decrease in angle N2 between lamellas 16 and shell surface 14 is accompanied by a gradual decrease in the distances between the connecting points of lamellas 16 with intermediate body 18 or respectively shell surface 14 of roll 10 in the direction of center plane E.

[0060] It can moreover be seen from FIGS. 1 and 2 that an outer circumference of intermediate body 18 is oriented, at least approximately, parallel to circumferential surface 14 of roller 10, wherein shell surface 14 coaxially surrounds longitudinal axis A of roller 10. Extending from intermediate body 18 is a compact but elastic support section 24, which mirror-symmetrically surrounds center plane E of roller 10 and against which fiber material web 11 rests without undergoing any appreciable transverse compression. This means that fibrous web 11 is compressed little or not at all in a direction transverse to the longitudinal extension of fibrous web 11. The compression of web 11 thus decreases inwards from edges 22 of roll 10.

[0061] In the second embodiment of roller 10, shown in FIG. 3, the distances between adjacent connecting points of lamellas 16, viewed in axial direction, are essentially the same. This also applies to angles of inclination N1. In order that a lamella 16, which is spaced further from center plane E of roll 10, and which is longer, and is thus more strongly deflected in the direction parallel to longitudinal axis A as a result of a force acting in the direction perpendicular to longitudinal axis A of roll 10 than a shorter lamella 16 arranged closer to center plane E, an intermediate body 18 is formed between lamellas 16 and base body 12, the diameter of which increases in the direction of center plane E of roll 10. Basically, if an intermediate body of constant thickness is used, a diameter of roll 10 could also increase continuously towards central plane E to achieve the same technical effect. At the maximum diameter of intermediate body 18 or roller 10, intermediate body 18 or roller 10 forms a support section 24 which has a comparable technical effect to support section 24 of roller 10 according to the first embodiment. The innermost lamellas 16 of the two roll halves, which are inclined towards each other, have a stabilizing effect so that here only small or negligible transverse forces are generated which act on web 11.

[0062] FIGS. 4 and 7 respectively show a roller arrangement that include both a roller 10, provided with lamellas 16, and a mating roller 26 rotatable about a longitudinal axis B. Roll 10 and mating roll 26 can be moved relative to each other in a direction in the x-y plane by the moving of longitudinal axes A, B of rolls 10, 26 in order to variably adjust or reduce a distance between rolls 10, 26. Rolls 10, 26 of the roll arrangement can be moved towards each other to such an extent that mating roll 26 exerts a force on lamellas 16 of roll 10 by way of web 11 which is conveyed between rolls 10, 26, causing lamellas 16 to deflect radially inwards.

[0063] It can be seen from FIGS. 4 and 7 that longitudinal axis A of roller 10 and longitudinal axis B of roller 26 are aligned at least approximately parallel to each other.

[0064] A shell surface 28 of mating roll 26 has a lower coefficient of friction than the outer surface of roll 10 formed by membrane 20. By minimizing friction between web 11 and shell surface 28, the compression/stretching of web 11 produced by roll 10 is efficiently implemented. To further reduce the coefficient of friction, mating roll 26 may have a shell surface 28 that is provided with openings not shown in the drawings. Through these openings, a fluid can leak from the interior of mating roll 26 to shell surface 28 of mating roll 26 to form a fluid film on shell surface 28 of mating roll 26. Moreover, a heated gas may escape through the openings to accelerate the drying process of fibrous web 11. Furthermore, it is also conceivable that (water) steam escapes from the openings in order to keep fibrous web 11 supple while being conveyed.

[0065] To reinforce the transverse compression of fibrous web 11, at least two rolls 10 provided with lamellas 16 may be assigned to mating roll 26, wherein rolls 10 and mating roll 26 respectively form a nip for receiving fibrous web 11. In the illustrated design example of FIG. 7, four rolls 10 are assigned to mating roll 26.

[0066] In the following, the mode of operation of lamellas 16 of rollers 10 is explained again with reference to FIGS. 4 to 6.

[0067] In the area of a nip (see dashed oval in FIG. 4), mating roll 28 causes compression (δy) in the y-direction of the layer formed by lamellas 16 and membrane 20. This causes lamellas 16 to tilt, wherein their radially outer end is being displaced (δz) in the z-direction (parallel to axis A). From the geometric considerations of FIG. 6, it can be gathered that the offset δz is a function of the angle of inclination N1 or N2 in an unloaded state of lamellas 16: the smaller N1, the greater the offset δz for a given compression δy. A section of web 11 resting on left-hand lamella 16 in FIG. 4 is pulled more to the right than a section of web 11 resting on right-hand lamella 16. The reverse is true for N2. A Membrane 20 (not shown here) can be used to apply a force acting in the y-direction to web 11 over an area instead of applying the force at a single point.

[0068] In other words, when rolls 10, 26 are in operation, fibrous web 11 first runs onto the undeflected lamellas 16 and is then conveyed into the nip or contact area between rolls 10, 26. In the contact area, lamellas 16 experience a deflection due to the force exerted by mating roll 26, whereby lamellas 16, figuratively speaking, are “tilted” inwards and thereby pull the web material lying on them with their radially outer ends from the edge regions, in the axial direction, towards center plane E. Fibrous web 11 thus follows the deflection of lamellas 16 or (if present) of membrane 20 in the axial direction. This results in fibrous web 11 being compressed transversely to its longitudinal extension. It is understood that when lamellas 16 are inclined outwardly, i.e. away from center plane E, web 11 undergoes elongation in the direction transverse to its longitudinal extension.

[0069] By varying the lamellas and/or intermediate body design in the axial direction, a transverse compression and/or transverse elongation of fibrous web 11 can thus be set in a targeted manner. Complex compression and/or elongation profiles can also be generated. The transverse compression or elongation can be increased by several rolls 10 provided with lamellas 16 (FIG. 7).

[0070] The concept according to the invention can also be implemented on high-performance lines with web speeds of higher than 1000 m/min. For example, a transverse shrinkage of 10 to 30% is achieved at basis weights of 70 to 200 g/m.sup.2 and paper moisture contents of 55 to 90%.

[0071] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

COMPONENT IDENTIFICATION LIST

[0072] 10 Roll

[0073] 11 Fibrous web

[0074] 12 base body

[0075] 14 shell surface

[0076] 16 lamellas

[0077] 16 intermediate body

[0078] 20 membrane

[0079] 22 edge

[0080] 24 support section

[0081] 26 mating roll

[0082] 28 shell surface

[0083] A longitudinal axis

[0084] B longitudinal axis

[0085] E center plane

[0086] E′ plane parallel to T

[0087] N1, N2 angle of inclination