EP1644577B1 - Pressing device - Google Patents

Description

The invention relates to a device for pressing a pressure shoe against a counter surface in a machine for producing paper, cardboard, tissue or other fibrous webs, wherein the device comprises at least two supported on a support body, at least partially flexible pressure body, the at least one cavity have, which can be acted upon with pressurized fluid to produce a predeterminable contact pressure via a corresponding pressure body volume.

Such a pressure shoe may, in particular, be part of a shoe press unit, in particular a shoe roll, and serve to form a flexible band or a flexible press jacket for forming a press nip extended in the direction of travel of the web against a, e.g. To press through an opposing surface formed by a counter roll. A corresponding shoe press unit can be provided, for example, for the production and / or treatment of a fibrous web, in particular paper or board web. In this case, the fibrous web can be guided together with at least one felt or wire through the respective press nip.

So far, the pressing of the pressure shoe is done either by an oil pressure bed or separate pressure piston. However, an oil pressure bed brings now in particular problems with regard to the seal with it. The use of separate pressure pistons is associated with the disadvantage of a deviation caused by the individual piston in the transverse pressure profile.

From the US-A-4,713,147 is a pressing device in a fiber-forming machine known whose located in the press nip gravity center is slidably disposed in the web running direction. This makes it possible to adapt to the working pressure profiles required for different types of paper in the press nip in the web running direction.

The invention has for its object to provide an improved pressing device of the type mentioned, in which the aforementioned problems are eliminated. In particular, a more uniform pressure distribution in the machine direction and in the transverse direction should be made possible in order to obtain the most level possible pressure profile. The occurrence of reaction forces in the machine direction and transverse direction should be reduced to a minimum.

This object is achieved in that are provided in a device of the type mentioned in order to adapt to the respective working width pressure body of different transversely measured length. In this case, the pressure body is preferably designed leak-free.

Due to this design, a more uniform pressure distribution in the machine direction and transverse direction is possible, so that the most level possible pressure profiles can be generated. This results in a relatively large, the pressure shoe or its lower part facing contact surface, which means that the pressure required to achieve the required line force can be kept relatively low. Compared to the Einzelkolbenanpressung lower pressure levels of the pressurized fluid are possible. The pressure body can be designed in particular as a lifting or pressure pad or as a pressure hose.

In a preferred practical embodiment of the pressing device according to the invention, the pressure body is designed in the form of a bellows. In this case, the bellows several, for example, three preferably have circumferential outer folds, whereby a relatively low initial height is achieved.

The pressure body may in particular have a generally cuboid shape.

However, the pressure body can also be formed by a preferably axially extending pressure hose.

The pressure surface of the pressure body acting on the pressure shoe or its lower part preferably corresponds at least substantially to the maximum pressure body cross section. This gives the largest possible contact surface, whereby the pressure required to achieve the required line force can be kept as low as possible.

Advantageously, a plurality of successive in the machine direction printing body and / or a plurality of transversely successive pressure body are provided.

In an expedient practical embodiment with a plurality of pressure bodies in succession in the machine direction, the pressure bodies for varying the line force and / or pressure longitudinal profile in the press nip formed with the counter surface are at least partially independently pressurized with pressurized fluid.

In an expedient practical embodiment with a plurality of transversely successive pressure bodies, the transversely successive pressure bodies for varying the linear force and / or pressure transverse profile in the press nip formed with the counter surface are at least partially independently pressurized with pressurized fluid.

Advantageously, at least three successive transversely successive pressure body are provided, whereby, for example, a border zone control is made possible.

In a preferred practical embodiment of the pressing device according to the invention with at least three successive transversely successive pressure bodies, the two edge-side pressure bodies have a smaller length measured in the transverse direction than the middle pressure body or bodies.

The pressure body preferably has one or more connections to the pressurized fluid supply. In this case, over the at least one connection advantageously also a vent and / or cooling and / or heating of the pressure hull possible.

As a pressurized fluid, for example water, gas, air and / or oil can be provided.

In an expedient practical embodiment of the inventive pressing device, the pressure body is mounted in a pressure bed of the support body. This is possible in all vertical and horizontal directions. In this case, the pressure body can be fixed in particular by a corresponding design of the pressure bed and the pressure shoe lower part.

Advantageously, the pressure shoe is associated with at least one retraction element, by which it can be moved away from the counter surface. By a suitable combination of pressure body or pressure bodies and retraction element or retraction elements a sensitive cross-profiling is possible.

A respective retraction element may in particular comprise at least one spring and / or at least one cylinder / piston element.

Advantageously, the length and shape of the pressure hull are at least partially determined by stops.

In the middle of the working width, for example, a stop bar may be provided. As a result, movements of the pressure shoe unit in the working width direction can advantageously be prevented and at the same time the deformation-free thermal expansion of the pressure shoe lower part be permitted. It can also be provided several stop strips, for example, each on the outer sides of the pressure shoe.

The stop bar may also be provided with sliding strips, which are preferably interchangeable, to reduce the friction between the stop bars and the bellows or the support body.

The stop bar in the middle of the working width is preferably made longer than the other stops. In addition, the stop bar is preferably performed in a U-shaped stop in the middle of the working width.

The fittings used for connection to the pressurized fluid supply are expediently arranged on the side of the pressure body facing away from the pressure shoe.

It is also advantageous to arrange the connections to the pressurized fluid supply diagonally relative to the pressure body. In adjacent pressure bodies, the fittings are preferably in pairs, in particular on the inlet side / outlet side alternately connected to each other. This results in short connection paths.

It is also preferable to provide the connection below the supporting body upper flange, that is, its horizontal part, and / or next to the web of the supporting body, that is, its vertical part. The connections can be stored protected here and take up no additional space.

Preferably, the pressure body is at least partially made of fiber-reinforced plastic.

The pressure shoe can be rotatably mounted according to a further embodiment of the invention in the machine direction, in particular in the center. In addition, the pressure shoe can also be in the cross machine direction, in particular, be stored several times. This has the advantage that results in a defined position of the pressure shoe without stop strips are required. As a result, the pressure shoe acquires an exactly calculable position, and the pressure profile can also be calculated precisely. Furthermore, the rotatable mounting in turn can be freely movably mounted in the horizontal direction.

According to the invention, two or more pressure bodies can also be arranged one above the other. In this case, one or more partition plates between the pressure bodies are preferably arranged. Instead of the lower pressure body and at least partially pressure piston can be provided. This further variations and adjustment options can be realized.

The inventive solution finds application in particular in drainage devices in machines for the production and / or finishing of paper, cardboard, tissue or other fibrous webs. In this case, the fibrous web is guided together with at least one dewatering belt through a press nip, which is formed by means of the pressing device. The line force in the press nip is preferably between 50 and 980 KN and in particular between 60 and 210 KN. Therefore, the use in the production of tissue webs is particularly suitable.

Figur 1

eine schematische Querschnittsdarstellung eines Druckschuhes mit zugeordneter Anpresseinrichtung,

Figur 2

eine schematische Darstellung des in der Figur 1 gezeigten Druckkörpers in einer Ansicht von unten,

Figur 3

eine schematische Darstellung einer weiteren Ausführungsform der Anpresseinrichtung mit zwei in Maschinenlaufrichtung aufeinanderfolgenden Druckkörpern sowie mit dem Druckschuh zugeordneten Rückholelementen,

Figur 4

eine schematische Darstellung einer weiteren Ausführungsform der Anpresseinrichtung mit in Maschinenlaufrichtung betrachtet lediglich einem Druckkörper, wobei auch in diesem Fall dem Druckschuh wieder Rückholelemente zugeordnet sind

Figur 5

eine schematische Darstellung einer Ausführungsform der Anpresseinrichtung mit drei in Querrichtung aufeinanderfolgenden Druckkörpern, und

Figur 6

eine schematische Darstellung einer Ausführungsform mit Druckschlauch.

The invention is explained in more detail below with reference to embodiments with reference to the drawing; in this show:

FIG. 1

a schematic cross-sectional view of a pressure shoe with associated pressing device,

FIG. 2

a schematic representation of the in the FIG. 1 shown pressure body in a view from below,

FIG. 3

2 a schematic representation of a further embodiment of the pressing device with two successive pressure bodies in the machine direction and with the pressure shoe associated return elements,

FIG. 4

a schematic representation of another embodiment of the pressing device viewed in the machine direction only a pressure body, which are associated with the pressure shoe again return elements in this case

FIG. 5

a schematic representation of an embodiment of the pressing device with three successive transversely successive pressure bodies, and

FIG. 6

a schematic representation of an embodiment with pressure hose.

FIG. 1 shows, as well as a part of the other figures, in a schematic cross-sectional view of a pressure shoe 10 with associated pressing device 12, as he already belongs to the prior art, but here again for a better understanding of the present invention will be explained in a little further consideration.

The pressing device 12 comprises at least one, on at least partially flexible pressure body 16 supported on a support body 14. The pressure body 16 has at least one pressurizable with pressurized fluid cavity 18 in order to generate a predeterminable contact pressure via a corresponding pressure body volume.

In the present case, the pressure body 16 only a single, continuous cavity 18.

Via the pressure shoe 10, a flexible band, for example, the flexible press cover of a shoe roll, be performed. By means of the pressing unit acting on the lower part 20 of the pressure shoe 10, the pressure shoe 10 and thus the relevant flexible belt can be pressed against an opposing surface to form an extended press nip, which can be formed for example by a counter-roller.

The executed in the present case as a lifting or pressure pad pressure body 16 is designed virtually leak-free. As based on the FIG. 1 can be seen, it is designed in the present case in the form of a bellows with, for example, three preferably circumferential outer folds 22.

The pressure body 16 should have as large as possible the pressure shoe 10 or its lower part 20 acting contact surface 24 in order to keep the pressure required to achieve the required line force as low as possible. This is achieved with the pressure body 16 according to the invention.

The pressure body 16 may for example have a generally cuboid shape. The pressure shoe 16 and the lower part 20 acting on it Contact surface 24 of the pressure body 16 may correspond at least substantially to the maximum pressure element cross-section.

In the FIG. 1 Moreover, a connection 26 to the pressure fluid supply can be seen.

As is clear from the FIG. 2 results, the pressure body 16 may in principle also have a plurality of compounds 26 for pressurized fluid supply. In the present case, two such connections 26 are provided. As based on the FIG. 2 can be seen, the connection of the pressure fluid supply serving fittings are expediently on the pressure shoe 10 (see also FIG. 1 ) facing away from the pressure body 16. In this case, a diagonal arrangement of these valves can be provided for an improved flow of the pressure fluid.

The pressure body 16 is expediently acted upon variable with the respective pressure fluid to produce a variably adjustable contact pressure by a corresponding variation of the pressure body volume.

As is clear from the FIGS. 3 to 5 results, several in the machine direction MD successive pressure body 16 and / or a plurality of transversely successive CD pressure body 16 may be provided.

FIG. 3 shows a schematic representation of an embodiment of the pressing device 12 with two consecutive in the machine direction MD pressure bodies 16 and associated with the pressure shoe 10 retreat or Rückholelementen 28th

The successive in machine running direction MD pressure body 16 are provided with separate connections 26 to the pressure fluid source 30. In the process, these pressure elements 16, which follow each other in machine direction MD, can be acted upon, in particular independently of one another, by pressurized fluid to vary the line force and / or pressure profile in the press nip formed with the counter surface. In the present case, although the pressure bodies 16 are connected to the same pressure fluid source 30, the supply line to one of the two pressure bodies 16 can be provided, for example, a pressure reducing valve 32 or the like, so that the two pressure bodies 16 can be subjected to different pressure, if required.

As based on the Figures 3 and 4 can be seen, viewed in the machine direction, both on the front and on the back of the pressure shoe 10 retraction or return elements 28 may be provided to move the pressure shoe 10 away from the opposing surface.

A respective retraction element 28 may comprise, for example, at least one spring and / or at least one cylinder / piston element.

FIG. 4 shows a schematic representation of an embodiment of the pressing device 12 with viewed in the machine direction MD only a pressure body 16. Also in this case, the pressure shoe 10 are associated with retraction elements 28 again. In the present case, a respective retraction element 28 may, for example, again comprise at least one spring and / or at least one cylinder / piston element.

As based on the Figures 3 and 4 can be seen, the retraction elements 28 on the side facing away from the pressure shoe 10 side of the support body 14 provided and extending through the support body 14 extending traction elements 34 may be connected to the pressure shoe 10.

As based on the FIG. 4 can be seen, the pressure body 16 is again provided with at least one connection 16 to the pressurized fluid supply 30.

FIG. 5 shows a schematic representation of an embodiment of the pressing device 12 with three consecutive in the transverse direction CD print bodies 16th

The pressure bodies 16 succeeding one another in the transverse direction CD can be acted upon again independently of one another by pressurized fluid for varying the line force and / or pressure transverse profile in the press nip formed with the mating surface. So you are again provided with separate connections 26 for pressurized fluid supply.

In the present case, for example, three consecutive pressure bodies 16 are provided in the transverse direction CD, but more than three or only two pressure bodies 16 may follow one another in the transverse direction.

In particular, it is also a combination of the embodiments according to FIG. 3 or 4 with the execution according to Fig. 5 conceivable.

In FIG. 6 the pressure shoe 10 is pressed in the form of axially extending pressure hoses via two pressure bodies 16 located side by side in the pressure bed 36 in the direction of rotation. Again, the expansion of the pressure hose is set in the pressing direction on the pressure of the pressure fluid in the pressure hose.

To adapt to the respective working width pressure element 16 may be provided of different lengths.

If at least three transversely successive CD printing elements 16 are provided, it is possible, for example via the marginal printing elements 16, to control the edge zone. As based on the FIG. 5 can be seen, the edge-side pressure body 16, for example, have a smaller measured in the transverse direction length than the or the middle pressure body 16th

Length and shape of the pressure body 16 may be limited in particular by stops.

The pressure shoe 10 facing the contact surface of a respective pressure body 16 is relatively large, so that the required oil pressure is kept correspondingly low. The fittings for connection to the pressure fluid supply are arranged on the underside of a respective pressure body 16 (see. FIG. 2 ). In this case, the valves can be arranged diagonally for improved pressure fluid flow (compare, in particular, again FIG. 2 ). The respective stroke results from a volume change by opening the folds 22 (cf. FIG. 1 ). With a limited number of outer folds 22 (see the embodiment of FIGS FIG. 1 with only three outer folds) results in a correspondingly lower starting height. The pressure bodies 16 may in particular consist of fiber-reinforced plastic or the like.

A respective pressure body 16 may be mounted in a pressure bed 36 of the support body 14 (see, in particular FIG. 1 ). In this case, the pressure body 16 be fixed by a corresponding design of the print bed 36 and the pressure shoe base 20.

LIST OF REFERENCE NUMBERS

10

pressure shoe

12

pressing device

14

supporting body

16

pressure vessels

18

cavity

20

lower part

22

outer fold

24

pressing surface

26

connection

28

Retraction or return element

30

Pressurized fluid source

32

Pressure reducing valve

34

tension element

36

printbed

37

storage

38

arrow

40

horizontal bearing

42

separating plate

MD

Machine direction

CD

transversely

Claims (39)

1. Device (12) for pressing a pressure shoe (10) against a mating surface in a machine for producing paper, board, tissue or other fibrous webs,
   the device comprising at least two pressure elements (16) which are supported on a supporting body (14) and are flexible, at least in some regions, and which have at least one hollow chamber (18) that can be pressurized with pressurized fluid in order to generate a predefinable pressing force via a corresponding pressure element volume,
   characterized in that
   in order to match the respective working width, pressure elements (16) of different lengths, measured in the transverse direction, are provided.
2. Pressing device according to Claim 1,
   characterized in that
   the pressure element (16) is designed to be leak-free.
3. Pressing device according to Claim 1 or 2,
   characterized in that
   the pressure element (16) is designed as a lifting or pressure pad.
4. Pressing device according to Claim 3,
   characterized in that
   at least one pressure element (16) is designed in the form of a bellows.
5. Pressing device according to Claim 4,
   characterized in that
   the bellows has a plurality of preferably circumferential outer folds (22).
6. Pressing device according to one of the preceding claims,
   characterized in that
   at least one pressure element (16) has a generally cuboidal shape.
7. Pressing device according to one of the preceding claims,
   characterized in that
   at least one pressure element (16) is formed from a pressure hose preferably extending axially.
8. Pressing device according to one of the preceding claims,
   characterized in that
   the pressing surface (24) of the pressure elements (16) that acts on the pressure shoe (10) or the lower part (20) of the latter corresponds at least substantially to the maximum pressure element cross section.
9. Pressing device according to one of the preceding claims,
   characterized in that
   the pressure elements (16) can be pressurized variably with pressurized fluid in order to generate a variably adjustable pressing force by means of an appropriate variation in the pressure element volume.
10. Pressing device according to one of the preceding claims,
    characterized in that
    it comprises a plurality of pressure elements (16) following one another in the machine running direction (MD).
11. Pressing device according to Claim 10,
    characterized in that
    the pressure elements (16) following one another in the machine running direction (MD) can be pressurized with pressurized fluid at least partly independently of one another in order to vary the line force and/or longitudinal pressure profile in the press nip formed with the mating surface.
12. Pressing device according to one of the preceding claims,
    characterized in that
    it comprises a plurality of pressure elements (16) following one another in the transverse direction (CD).
13. Pressing device according to Claim 12,
    characterized in that
    the pressure elements (16) following one another in the transverse direction (CD) can be pressurized with pressurized fluid at least partly independently of one another in order to vary the line force and/or transverse pressure profile in the press nip formed with the mating surface.
14. Pressing device according to Claim 12 or 13,
    characterized in that
    at least three pressure elements (16) following one another in the transverse direction (CD) are provided.
15. Pressing device according to one of the preceding claims,
    characterized in that
    at least three pressure elements (16) following one another in the transverse direction (CD) are provided, and the two pressure elements (16) at the edges have a shorter length, measured in the transverse direction, than the central pressure element or elements (16).
16. Pressing device according to one of the preceding claims,
    characterized in that
    in order to form a modular system, pressure elements (16) having a length which corresponds to a fraction of a working width are provided.
17. Pressing device according to one of the preceding claims,
    characterized in that
    at least one pressure element (16) has one or more connections (26) to the pressurized fluid supply.
18. Pressing device according to Claim 17,
    characterized in that
    at least one pressure element (16) can be vented and/or cooled and/or heated via the at least one connection (26).
19. Pressing device according to one of the preceding claims,
    characterized in that
    the pressurized fluid provided is water, gas, air and/or oil.
20. Pressing device according to one of the preceding claims,
    characterized in that
    at least one pressure element (16) is mounted in a pressure bed (36) of the supporting body (14).
21. Pressing device according to Claim 20,
    characterized in that
    at least one pressure element (16) is fixed by means of an appropriate configuration of the pressure bed (36) and of the pressure shoe lower part (20).
22. Pressing device according to one of the preceding claims,
    characterized in that
    the pressure shoe (10) is assigned at least one withdrawal element (28), by means of which it can be moved away from the mating surface.
23. Pressing device according to Claim 22,
    characterized in that
    the withdrawal element (28) comprises at least one spring and/or at least one cylinder/piston element.
24. Pressing device according to one of the preceding claims,
    characterized in that
    length and shape of at least one pressure element (16) are at least partly determined by stops.
25. Pressing device according to one of the preceding claims,
    characterized in that
    a stop bar is provided in the centre of the working width and/or on the outer sides of at least one pressure shoe (10).
26. Pressing device according to Claim 25,
    characterized in that
    the stop bar is provided with preferably replaceable sliding strips.
27. Pressing device according to Claim 25 or 26,
    characterized in that
    the stop bar in the centre of the working width is longer than the other stops.
28. Pressing device according to one of Claims 25 to 27,
    characterized in that
    the stop bar in the centre of the working width is guided in a U-shaped stop.
29. Pressing device according to one of the preceding claims,
    characterized in that
    the fittings used for the connection to the pressurized fluid supply are arranged on the side of at least one pressure element (16) that faces away from the pressure shoe (10).
30. Pressing device according to one of the preceding claims,
    characterized in that
    the connections to the pressurized fluid supply (26) are arranged diagonally relative to at least one pressure element (16).
31. Pressing device according to one of the preceding claims,
    characterized in that
    the fittings of adjacent pressure elements (16) are connected to one another in pairs, in particular alternately on the inlet side/outlet side.
32. Pressing device according to one of the preceding claims,
    characterized in that
    the connection is provided underneath the supporting body upper flange and/or beside the web of the supporting body (14).
33. Pressing device according to one of the preceding claims,
    characterized in that
    at least one pressure element (16) consists at least partly of fibre reinforced plastic.
34. Pressing device according to one of the preceding claims,
    characterized in that
    the pressure shoe (10) is mounted, in particular centrally, such that it can rotate in the machine running direction (MD).
35. Pressing device according to one of the preceding claims,
    characterized in that
    the pressure shoe (10) is mounted, in particular multiply, such that it can rotate in the machine transverse direction (CD).
36. Pressing device according to Claim 34 or 35,
    characterized in that
    the rotatable mounting (36) is in turn mounted such that it can move freely in the horizontal direction.
37. Pressing device according to one of the preceding claims,
    characterized in that
    two or more pressure elements (16) are arranged above one another.
38. Pressing device according to Claim 37,
    characterized in that
    one or more dividing plates (42) are arranged between the pressure elements (16) arranged above one another.
39. Pressing device according to Claim 37 or 38,
    characterized in that
    instead of the lower pressure elements (16), pressure pistons are provided, at least to some extent.

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