EP2420617B1 - Calendar - Google Patents

Description

The invention relates to a calender of a first and a second treatment nip forming element, wherein the first treatment nip forming element has a fixed, mounted at its ends axis about which a soft bendable jacket is rotatably disposed, wherein the jacket with each end to a , is rotatably mounted on a non-rotating part rotatably mounted part of a terminal device, and wherein at least one radially movable pressure element between the axis and the jacket is arranged, which is movably guided over a first stroke and via which a force from the axis on the jacket towards the treatment nip can be introduced, and wherein the two terminal devices on a second stroke relative to the axis radially and rectified with the pressing member are displaceable, wherein a Relativhubbegrenzer is provided between at least one pressing element and a terminal, which is activated when the difference of the first un d the second stroke exceeds or falls below a certain level.

As a rule, such calenders are paper or board-type satin-finishing machines which consist of at least two rollers. Since a roller can also be replaced by an investment tape, the term "treatment nip forming element" is used instead. The two elements are placed together in operation under a certain pressure, between them, in the treatment nip, the paper or board web is then treated.

If the elements forming a treatment nip are rollers, for many years a heatable roller with a hard and smooth surface is often used against a so-called bending adjustment roller hired. The Biegeeinstellwalzen have a number of support elements, which are supported on a fixed axis
Press against a rotating sheath towards the treatment nip. Exemplary here is the DE 29 42 002 C2 named as state of the art. Both the terminal device, which carries the jacket tube, and the pressing elements can perform a stroke in the direction of the Behandlungsnips and back in this embodiment. In the past, such a jacket always consisted of a relatively stiff metallic tube, possibly with a softer material. In this type of Biegeeinstellwalzen the coat is at least so stiff that it remained dimensionally stable even without the inclusion in terminals.

Instead of individual support elements often acts as a continuous shoe, as it is for example in the DE 299 02 451 U1 Can be found. For both variants, the term pressure element is used in this application. The pressure elements usually work hydrodynamically or hydrostatically to avoid friction with the jacket. In the calender development so soft coats, mainly made of epoxy resin, polyurethane or composite, were used.

From the EP 1 333 121 A1 For example, a shoe roll of a calender is known in which the support disks carrying the shell can execute a radial stroke in a guide.

The soft bending jacket is moved by the pressing elements in the direction of treatment nip, which bulges him in the calendering area, while maintaining the round shape near the rotating parts of the terminal equipment. This results in high occurring alternating loads. Despite the flexibility of the plastic sheath this is claimed at least at its axial ends to a maximum, which the Life reduced greatly. Remedy should be in accordance with the DE 196 45 407 A1 to provide a support device on the terminal of a press, which is radially flexible, in particular elastic. One wants to let the counter roll dive into the shoe roll here. However, such a construction is extremely difficult to realize due to sealing problems and also insufficient in its effect.

In the EP 0 619 399 B1 Although not a calender, which would be suitable for a calendering, but a press shown, but the patent discloses a treatment nip forming element, called in the preamble, also for the present invention desired independent first stroke movement of a pressure element (shoe) of the second stroke movement of a terminal that receives the jacket separates. The second stroke is realized in this patent via an eccentric, so that it comes to a concern or a more distant distance of the shell with respect to the Behandlungsnip. Here, however, there is a great danger that the pressure in the cylinders under the shoe is not sufficiently degraded, if over an eccentric rotation already the coat is withdrawn from the treatment nip. The eccentric also unwanted transverse forces are introduced into the jacket.

Particularly stressed is the jacket in addition, when the pressing member is formed on the second element facing and its contour adapted surface correspondingly concave. The jacket then runs over the upstanding edges in the inlet and outlet of the shoe strongly curved convex, while it is concavely curved in between.

In addition, the axis is deflected due to the line load in the treatment nip. The end directions, which receive the jacket, will thus lean towards one another on the side facing the treatment nip, which in turn leads to an alternating load in the rotating jacket.

Instead of the mentioned shoe rollers is now also used as a treatment nip forming element a circumferentially encircling, circumferential metal band. It has been found from the consideration of calendering results that metallic tapes capable of forming a wide nip achieve a particularly notable quality in some types of paper or board.
However, in a shoe roll, a metal sheet sheath is hard to imagine, and has never been realized in any case, because the risk of overstressing and tearing is too great.

Overall, it is the object of the invention to provide more security against overstressing of a flexurally soft, possibly comprising a metal sheet jacket of a treatment nip forming element in a calender.

We solve the problem in that the specific measure of the difference of the first and the second stroke when closing the Behandlungsnips (4) is different than when opening.

The permissible difference in strokes to be defined for each embodiment is determined, for example, by mathematical methods. In this way, impermissible stresses acting on the shell, which are generated by an unmeasured stroke of the pressing elements to the stroke of the terminals and thus of the shell, completely be avoided. As a result, the life of the shell is significantly increased, which minimizes the cost of the operator of the calender coat or roll change.

The particular measure is different for the difference of the first and second hubs when closing the treatment tip than when opening. When closing the treatment gap care must be taken, for example, that the pressure element of the jacket bearing terminal not too early. After a certain initial "idle stroke", the pressing element has otherwise reached the casing inner wall and presses itself into it. This can lead to unacceptable strains of the shell, especially since it remains circular in its clamping at the terminal. When opening the treatment tip, the situation looks completely different. Here, care must be taken that the, in this case, lowering stroke of the terminal does not lead the backward movement of the pressure element. It is important to point out that the processes just described only apply if the first element forming a treatment nip is arranged below the second one. In the event that the first element forming a treatment rip is arranged above the treatment nip, the processes behave conversely in the same way.

It is advantageous if the relative stroke limiter is formed by an at least indirectly acting mechanical driver arrangement. A driver arrangement is an easy way to limit the relative movement between pressure element and terminal. For this purpose, often two components connected to the pressure element and the terminal devices, which are provided with a mutual stop. At the same time, the components collide with their stops precisely when the stresses in the jacket threaten to become too great.

Alternatively, it is advantageously ensured that the relative stroke limiter is formed by a control device monitoring the stroke paths for at least one cylinder-piston drive or the like for the first and / or second stroke. For this purpose, it is only necessary to monitor the strokes or the differential stroke by a suitable transducer and, if the difference is too high, to control the actuators, that is to say a cylinder-piston drive or the like. For this purpose, for example, in the pressing elements, a fluid pressure, which serves to move the pressing elements, changed. Alternatively, of course, the adjusting device which travels the terminal device can also be correspondingly influenced and optionally rotated in its direction of travel.

It is particularly preferred if the determined dimension is determined at least partially from an immersion depth of the pressure element into the cylindrical shell contour. The immersion depth of the pressure element in the jacket is the decisive factor for the stress of the jacket. The immersion process must be limited to a maximum, in particular when closing the treatment tip. Depending on the jacket material, maximum deformation bulges of the jacket of 10 to 30 mm have proven to be just barely portable. However, the aim is that the penetration depth is essentially zero. Here, the term is essentially used because, of course, in a concave-shaped pressure element in the inlet and outlet area is pushed further outward than in the middle part of the pressure element.

It is favorable if the non-rotating part of the terminal device is tiltable with respect to the axis. As a result, the terminal devices do not tilt in the region of the treatment nips and the jacket is not compressed accordingly. Conversely, for the side of the jacket facing away from the treatment nip, there is no additional one

Tensile stresses are introduced into the jacket. Overall, the jacket thus remains essentially completely cylindrical.

Preferably, the two terminals are connected to each other via at least one cross member. This gives the cylindrical shape additional stability and also ensures the Traverse that both terminals can be operated in its stroke absolutely synchronously.

It is advantageous if the non-rotating parts of the terminal devices and the traverse (s) form a coherent frame construction. This is then composed, as it were, of a plurality of traverses, except in the region of the pressing elements between the terminal devices, which are arranged distributed over the circumference. Such a frame construction can be performed more accurately and also has a protective function for arranged on the axis lines (for example, for the pressure fluids of the pressure elements) or cables (for example, for the displacement transducer or other measuring devices).

Such a traverse or in particular the frame construction offers even more advantages. It is possible that a jacket guide element is attached to at least one traverse. In the case of flexible mantles, fluttering on the circumference in front of and behind the treatment nip can be limited if not completely prevented. Preferably, such a jacket guide element is adjustable in its contact pressure on the jacket.

Or it is advantageously ensured by a traverse or the frame construction that at least one guide for the at least one pressing element is provided for lateral support of the first stroke on at least one cross member. This is particularly useful for long first strokes, because then the pressing elements can not tilt away because of the frictional forces on the jacket in the Behandlungsnip.

For the second stroke of the terminal devices, at least one actuating element is preferably provided in the nip direction and / or in the opposite direction, which is supported on the axis and engages the non-rotating part of the terminal device and / or a crossbeam and / or the frame construction. With such an actuator, the second stroke can be implemented in a simple manner. In particular, hydraulic actuators, which are very similar to those of the pressure elements, have proved successful.

It is also advantageous if a plurality of adjusting elements are provided for the second stroke of the terminal devices, of which at least one obstructs an axial relative movement between the axis and terminal device. That is, the location elements are distributed in multiple execution over the length of the roller. Because of the axle curvature, they can then attack in particular on the traverse or the frame construction and thereby extend different distances. As a result, the jacket can be moved parallel to the unloaded axis and avoid possible stresses. In this context, it is also useful to provide at least one of several control elements, which is more or less as a fixed bearing on the traverse or engages the frame construction, while the other actuating elements allow axial movement of the traverse or the frame structure in the axial direction. A distortion of the control elements is thus also avoided.

It is favorable if the second stroke of the terminal device takes place via a sliding guide of at least one plane surface on the axis and at least one flat surface on the terminal device or a component connected to it. Namely, such a guide permits exactly the two desired degrees of freedom for the terminal devices: the lifting movement in the direction of the treatment nip and the tilting movement in relation to the axial curvature. This can be realized in particular when the surface normals of the existing sliding surfaces run perpendicular to a surface which extends through the treatment nip and axis. In this case, the center of the pressure element does not necessarily have to run exactly onto the central axis of the second element forming a treatment nip.

Preferably, the calender is closed only by the first and second stroke and open. Thus, two otherwise necessary cylinders are dispensed with at the axle ends of the first element forming a treatment nip. It saves not only the cylinder units and their supply and control. Rather, one also avoids additional bending moments on the axis and thus indirectly on the mantle. The necessary stroke for closing the treatment nip in the calender at a height of 20 to 200 mm is thus generated by the inner stroke of the first treatment nip-forming element alone.

• Figur 1 einen schematischen, ausgeschnittenen Längsschnitt durch einen erfindungsgemäßen Kalander
• Figur 2 eine vereinfachte perspektivische Darstellung des ersten einen Behandlungsnip bildenden Elements des Kalanders
• Figur 3 einen Teilquerschnitt des ersten und des zweiten einen Behandlungsnip bildenden Elements des Kalanders

The invention is explained in more detail below with reference to exemplary embodiments with reference to the drawings. Show it

• FIG. 1 a schematic, cut longitudinal section through a calender according to the invention
• FIG. 2 a simplified perspective view of the first treatment nip forming element of the calender
• FIG. 3 a partial cross section of the first and the second treatment nip forming element of the calender

FIG. 1 It is composed of a first element forming a treatment nip, a shoe roller 2, and a second element forming a treatment nip, a heating roller 3. Where the two rollers 2, 3 abut each other, they form a Behandlungsnip 4 for a paper or board web, not shown. The shoe roll 2 has a non-rotatably mounted at its ends axis 5, around which a bend-soft coat 6 is rotatably mounted. The jacket 6 preferably consists at least in part of a metal, and is particularly preferably a steel jacket of a 0.5 to 3 mm thick sheet metal. However, the invention should also be able to be used with coats of, for example, epoxy resin, polyurethane or composite.

The jacket 6 is accommodated in so-called terminal devices 7, the terminal devices being composed of a rotating part 7.1 rotating with the jacket and a non-rotating part 7.2 held non-rotatably on the shaft. The rotating part 7.1 is mounted by means of the rolling bearing 8 on the non-rotating part 7.2.

A radially displaceable pressure element 9 is able to act on the jacket 6 from the inside in the direction of the treatment nips. Such pressing elements may have different known designs. The range extends here from convex-shaped, so the cylindrical shell shape adapted, individual support elements, which are arranged in a row axially adjacent to each other, to a concave shaped continuous shoe. In this embodiment, an axially continuous shoe is considered as pressing element 9, which can be moved by a plurality of cylinder-piston actuators 10 in a first stroke in the direction of treatment nip. These drive to different heights, when the axis is bent due to the line load, so that can form in straight Behandlungsnip 4. The lubrication between the shell and pressure element is usually carried out by a lubricant which passes there on a hydrostatic or hydrodynamic way, as is known from the prior art.

When the piston-cylinder drive 10 raises the pressing elements 9 too much (with respect to the direction becomes here Fig. 1 considered), so they finally hit the inner wall of the shell 6, and even further extension, the sheath 6 is bulged to the treatment nip 4 out. Depending on the jacket material, this was also permissible for older shoe rollers up to a certain extent of a maximum of 10 to 30 mm. A compromise had to be made here between the deformation of the jacket, which requires a concave-shaped shoe, which presses against a heating roller, and the lowest possible alternating load of the jacket 6 during circulation. However, this invention seeks To avoid the stresses on the coat largely to ensure a longer life expectancy.

For this reason, a Relativhubbegrenzer 13 is provided which largely prevents buckling of the shell. So that it can act at all, care must be taken for a second stroke of the terminal device 7 and thus of the jacket 6. For this purpose, an actuating element 11 is provided, which is also essentially formed by a cylinder-piston drive 12. Of course, electric drives, for example, with Spindelhub, can be provided here.

In FIG. 1 Two options for the design of the Relativhubbegrenzers are shown.

In a particularly preferred embodiment, a mechanical driver assembly 14 is provided. In this case, an engagement 15 which is attached directly or indirectly to the pressure element 9, guided in a groove 16 on the terminal device 7 or a component connected thereto. In this case, a stop 17 is present, which is reached when the difference of the first and second stroke exceeds or falls below a certain level. In the present case, when lifting the pressing element and reaching the stop 17, the terminal 7 is raised together with the jacket 6 with. In this way, it is ensured that the pressing elements are not or only very slightly immersed in the cylindrical shape of the shell 6.

Another preferred embodiment of the Relativhubbegrenzers is determined by a control system. For this purpose, two displacement sensors 18 and 19 are provided which control the stroke of the terminal 7 and the stroke of Monitor pressing element 9. The two strokes to be measured are indicated by a dotted line. The measured variables are evaluated in a computer unit, not shown, and the manipulated variables for the cylinder-piston actuators 10 and 12 are output as control variables.

If the axis 5 bends due to the line load in the treatment nip 4, there is a risk that the terminal devices no longer run parallel to each other. Therefore, it makes sense to connect the non-rotating parts of each terminal with each other with a crossbar 20. This is in the FIG. 2 clearly shown in three-dimensional form. In addition, the components stand out in different shades of gray. In the terminal 7 of the non-rotating part 7.2 is shown darker, while the rotating part 7.1, which also receives the jacket, was left white. The two non-rotating parts 7.2 of the terminals 7 are connected to each other via the dark trusses 20. In this embodiment, four trusses are provided, which are mounted at 12, 3, 6 and 9 o'clock. Of course, the trusses can also be interconnected and thus represent a frame construction. The treatment nip facing Traverse has a longitudinal recess, which serves as Andrückelementführung. Thus, a first stroke of the pressure element, which can be up to 200 mm, laterally supported.

The axle has a plurality of cylinder-piston actuators 10 to urge the pressing member (9), in this case the shoe, toward the treatment nip. The terminal devices are independent of, until possibly a driver is activated by the cylinder-piston actuators 10 raised and lowered. They are guided laterally on the axis. This slide 24 is designed so that the surface normals of Sliding surfaces perpendicular to a surface extending through Behandlungsnip 4 and axis 5, extend. The sliding guide 24 simultaneously allows a tilting movement of the terminal 7 in order to compensate for the Achsdurchbiegung.

On the trusses 20 continue to be seen cladding guide elements 22, which ensure that the flexible jacket retains its cylindrical shape during rotary operation.

FIG. 3 clarifies once more in more detail the structure of the calender in a section. It can be seen above a second element forming a Behandlungsnip, so for example a heating roller 3. Dotted underneath the paper or board web 30 is indicated. In the treatment nip 4, it has contact with the heating roller 3 and the flexible casing 6 of the first treatment nip forming element, in this case a shoe roll. The shoe, so the pressure element carries the designation 9. It is employed via the cylinder-piston drive 10 in the direction of heating roller 3. The cylinder-piston drive 10, I is the axis 5. A pressure chamber 27 below the piston 28 is supplied for example by drilling in the axis 5 with a pressurized fluid. There one builds up the pressure to press the pressure element against the paper or board web 30. As with known hydrostatic support elements can lead in a manner not shown, a capillary from the pressure chamber 27 into a pocket 29 of the pressure element to establish a pressure fluid cushion there, which protects the jacket from wear.

On the crossmember 20 one or both sides an angle 25 is attached. This supports via an intermediate sliding member 26, the pressing member 9. Even a relatively large first stroke is against Secured tilting. A lateral adjustability makes it possible to use different width pressing elements. Depending on the type of paper or cardboard, shoe widths of 30 to 200 mm are desired.

Parallel to the cylinder-piston drive 10 or a series of drives is provided a cylinder-piston drive 12 or one or two rows of them. About the cylinder-piston drive 12, the cross member 20 is raised in a second stroke, which is connected to the terminals, which in turn receive the jacket. Thus, the two strokes can run independently of each other until the Relativhubbegrenzer begins, in the description of the FIG. 1 was explained in detail and in FIG. 3 therefore is no longer shown for clarity.

LIST OF REFERENCE NUMBERS

1

calender

2

first treatment nip forming element (in the embodiment shoe roll)

3

second treatment nip forming element (in the embodiment heat roller)

4

Behandlungsnip

5

axis

6

Biegeweicher coat

7

terminal

7.1

Rotating part

7.2

Non-rotating part

8th

camp

9

pressing element

10

Cylinder-piston drive

11

actuator

12

Cylinder-piston drive

13

Relativhubbegrenzer

14

tappet

15

intervention

16

groove

17

attack

18

transducer

19

transducer

20

traverse

21

frame construction

22

Coat guides

24

slide

25

angle

26

Slide

27

pressure chamber

28

piston

29

bag

30

Paper or board web

Claims (14)

1. Calender comprising a first and a second element (2, 3) which form a treatment nip (4), the first element (2) which forms the treatment nip (4) having a stationary axle (5) which is mounted at its ends and around which a flexible shell (6) is arranged rotatably, the shell (6) being fastened with each end to a rotating part (7.1) of an end device (7), which rotating part (7.1) is mounted rotatably on a non-rotating part (7.2), and at least one radially movable pressing element (9) being arranged between the axle (5) and shell (6), which pressing element (9) is guided such that it can be moved over a first stroke path, and via which pressing element (9) a force can be introduced from the axle (5) onto the shell (6) in the direction of the treatment nip (4), and it being possible for the two end devices (7) to be displaced radially and oriented identically with the pressing element (9) on a second stroke path with respect to the axle (5), a relative stroke limiter (13) being provided between at least one pressing element (9) and an end device (7), which relative stroke limiter (13) is activated when the difference of the first and the second stroke exceeds or undershoots a defined dimension, characterized in that the defined dimension for the difference of the first and the second stroke is different in the case of closing the treatment nip (4) than in the case of opening.
2. Calender according to Claim 1, characterized in that the relative stroke limiter (13) is formed by an at least indirectly acting mechanical driver arrangement (14).
3. Calender according to Claim 1, characterized in that the relative stroke limiter (13) is formed by a regulating device which monitors the stroke paths for at least one cylinder/piston drive (10, 12) for the first and/or second stroke.
4. Calender according to one of Claims 1 to 3, characterized in that the defined dimension is defined at least partially from a penetration depth of the pressing element (9) into the cylindrical shell contour.
5. Calender according to one of Claims 1 to 4, characterized in that the non-rotating part (7.2) of the end device (7) can be tilted in relation to the axle (5).
6. Calender according to one of Claims 1 to 5, characterized in that the two end devices (7) are connected to one another via at least one crossmember (20) .
7. Calender according to either of Claims 5 and 6, characterized in that the non-rotating parts (7.2) of the end devices (7) and the crossmember/crossmembers (20) form a contiguous frame construction (21).
8. Calender according to either of Claims 6 and 7, characterized in that a shell guiding element (22) is attached on at least one crossmember (20).
9. Calender according to one of Claims 6 to 8, characterized in that at least one guide (23) for the at least one pressing element (9) is provided for the lateral support of the first stroke on at least one crossmember (20).
10. Calender according to one of Claims 1 to 9, characterized in that at least one actuating element (11) is provided for the second stroke of the end devices (7) such as to act in the nip direction and/or opposite direction, which actuating element (11) is supported on the axle (5) and acts on the non-rotating part (7.2) of the end device (7) and/or a crossmember (20) and/or the frame construction (21).
11. Calender according to Claim 10, characterized in that a plurality of actuating elements (11) are provided for the second stroke of the end devices (7), of which actuating elements (11) at least one impedes an axial relative movement between the axle (5) and end device (7).
12. Calender according to one of Claims 1 to 11, characterized in that the second stroke of the end device (7) takes place via a sliding guide (24) of at least one planar sliding guide face on the axle (5) and at least one planar sliding guide face, bearing on the former, on the end device (7) or a component which is connected to it.
13. Calender according to Claim 12, characterized in that the surface perpendiculars of the sliding faces (24.1, 24.2) run perpendicularly with respect to a plane which extends through the treatment nip (4) and axle (5).
14. Calender according to one of Claims 1 to 13, characterized in that the calender (1) can be closed and opened only by the first and second stroke.

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