EP1712674A2 - Pressing device - Google Patents

Abstract

In a papermaking process a variable-position shoe is applied to a moving belt or the inner face of a flexible drum mantle. The shoe consists of a bellows bag (16) is contained within a surrounding tray bearing plate (14). The bag is expands under hydraulic pressure delivered via an inlet (26). The roughly rectangular bellows bag has a series of surrounding outer folds (22) and is essentially an axial pressure hose.

Description

The invention relates to a device for pressing a pressure shoe against a counter surface.

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.

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 even pressure distribution in the machine direction and in the transverse direction be made possible to obtain the best 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 the device comprises at least one supported on a support body, at least partially flexible pressure body having at least one cavity which can be acted upon with pressurized fluid to produce a predetermined pressure body volume a predetermined contact pressure. 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 risk of leakage of the pressurized fluid is virtually eliminated. Moreover, there is a reduced production cost and ease of assembly.

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 linear 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 in the transverse direction successive pressure body for varying the linear force and / or pressure transverse profile in the press nip formed with the mating surface 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.

To adapt to the respective working width pressure body of different lengths can be provided.

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.

To form a modular system can be provided with a length corresponding to a fraction of a working width pressure element according to a further embodiment of the invention. Depending on the working width, more or less such pressure bodies can then be arranged behind one another or next to one another. If necessary, even lower-length equalizing bodies are used to fill a remaining portion of the working width.

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 pressing device according to the invention, 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,

Figur 6

eine schematische Darstellung einer Ausführungsform mit Druckschlauch,

Figur 7

eine Darstellung entsprechend Figur 1 einer weiteren Variante der Erfindung, und

Figur 8

eine Darstellung gemäß Figur 1 noch einer Variante der Erfindung.

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

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

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

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

FIG. 6

a schematic representation of an embodiment with pressure hose,

FIG. 7

a representation corresponding to Figure 1 of a further variant of the invention, and

FIG. 8

a representation of Figure 1 nor a variant of the invention.

FIG. 1 shows a schematic cross-sectional view of a pressure shoe 10 with an associated pressing device 12.

The pressing device 12 comprises at least one pressure element 16 which is supported on a support body 14 and is at least partially flexible. The pressure element 16 has at least one cavity 18 which can be acted upon with pressurized fluid in order to generate a predeterminable contact pressure via a corresponding pressure element 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 can be seen from the figure 1, 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 addition, FIG. 1 shows a connection 26 for the pressure fluid supply.

As can be seen from FIG. 2, the pressure body 16 can in principle also have a plurality of connections 26 for the supply of pressurized fluid. In the present case, two such connections 26 are provided. 2, the fittings serving for connection to the pressurized fluid supply are expediently arranged on the side of the pressure body 16 facing away from the pressure shoe 10 (see also FIG. 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 can be seen from FIGS. 3 to 5, a plurality of pressure bodies 16 following one another in the machine direction MD and / or a plurality of pressure bodies 16 succeeding each other in the transverse direction CD can be provided.

FIG. 3 shows a schematic illustration of an embodiment of the pressing device 12 with two pressure bodies 16 following one another in the machine direction MD, as well as retraction or return elements 28 associated with the pressure shoe 10.

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 one another in the machine running direction MD, can be acted upon in particular independently of one another by pressurized fluid in order to vary the line force and / or pressure longitudinal 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 necessary.

As can be seen with reference to FIGS. 3 and 4, retraction or return elements 28 can be provided in the machine direction both on the front side and on the rear side of the pressure shoe 10 in order 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.

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

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

FIG. 5 shows, in a schematic representation, an embodiment of the pressing device 12 with three pressure bodies 16 following each other in the transverse direction CD.

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, a combination of the embodiments according to FIG. 3 or 4 with the embodiment according to FIG. 5 is also 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 can be seen with reference to FIG. 5, the marginal pressure bodies 16 can be made e.g. have a smaller length measured in the transverse direction than the or the middle pressure body 16.

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 Figure 2). In this case, the valves can be arranged diagonally for improved pressure fluid flow (cf., in particular, FIG. 2). The respective stroke results from a volume change by opening the folds 22 (cf., in particular, FIG. With a limited number of outer folds 22 (compare the embodiment according to Figure 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 can be mounted in a pressure bed 36 of the support body 14 (cf., in particular, FIG. In this case, the pressure body 16 be fixed by a corresponding design of the print bed 36 and the pressure shoe base 20.

FIG. 7 shows a pressure shoe 10, which is rotatably mounted via a bearing element 36 in the machine direction MD, as indicated by arrow 38. The bearing 36 is in turn mounted freely movable in a horizontal bearing 40. In this embodiment, two pressure bodies 16 are arranged one behind the other in the machine direction MD, as shown. In addition, one, preferably multiple, rotatable mounting in the cross machine direction CD can be provided, which is not shown here.

FIG. 8 shows a variant in which two pressure bodies 16 are arranged one above the other. Between the two pressure bodies 16, a partition plate 42 is provided. Instead of the lower pressure body 16 and pressure piston can be provided. In addition, a plurality of pressure bodies 16 can be arranged next to one another in each case in the cross machine direction CD, as has been described for the previous exemplary embodiments. The same applies to the variant of FIG. 7.

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 (18)

Pressing device, which comprises at least one on a support body (14) supported, at least partially flexible pressure body (16) having at least one cavity (18) which can be acted upon with pressurized fluid to produce a predetermined pressure body volume over a corresponding pressure body volume,
characterized,
in that at least one retraction element (28) is associated with the pressure shoe (10), by means of which it can be moved away from the opposing surface. Pressing device according to claim 1,
characterized,
in that the retraction element (28) comprises at least one spring and / or at least one cylinder / piston element. Pressing device according to one of the preceding claims,
characterized,
that length and shape of at least one pressure body (16) are at least partially determined by stops. Pressing device according to one of the preceding claims,
characterized,
that in the middle of the working width and / or on the outer sides of at least one pressure shoe (10) is provided a stop bar. Pressing device according to claim 4,
characterized,
that the stop bar is provided with, preferably exchangeable, sliding strips. Pressing device according to claim 4 or 5,
characterized,
that the stop bar in the middle of the working width is longer than the other stops. Pressing device according to one of claims 4 to 6,
characterized,
that the stop bar is guided in the middle of the working width in a U-shaped stop. Pressing device according to one of the preceding claims,
characterized,
in that the fittings serving for connection to the pressurized fluid supply are arranged on the side of at least one pressure body (16) facing away from the pressure shoe (10). Pressing device according to one of the preceding claims,
characterized,
that the connections to the pressure fluid supply (26) are arranged relative to at least one pressure body (16) diagonally. Pressing device according to one of the preceding claims,
characterized,
that the valves of adjacent pressure bodies (16) are in pairs, in particular on the inlet side / outlet side alternately connected to each other. Pressing device according to one of the preceding claims,
characterized,
that the connection is provided below the supporting body upper belt and / or next to the web of the supporting body (14). Pressing device according to one of the preceding claims,
characterized,
in that at least one pressure body (16) consists at least partially of fiber-reinforced plastic. Pressing device according to one of the preceding claims,
characterized,
is rotatably supported that the pressure shoe (10) in the machine direction (MD), in particular centrally. Pressing device according to one of the preceding claims,
characterized,
that the pressure shoe (10) in the cross-machine direction (CD), in particular multiple, is rotatably mounted. Pressing device according to claim 13 or 14,
characterized,
that the rotatable mounting (36) in turn is freely movable in the horizontal direction. Pressing device according to one of the preceding claims,
characterized,
that two or more pressure bodies (16) are arranged one above the other. Pressing device according to claim 16,
characterized,
in that one or more separating plates (42) are arranged between the pressure bodies (16) arranged one above the other. Pressing device according to claim 16 or 17,
characterized,
that instead of the lower pressure body (16) at least partially pressure piston are provided.

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