CN117062951A

CN117062951A - Multi-layer forming machine

Info

Publication number: CN117062951A
Application number: CN202280024909.3A
Authority: CN
Inventors: P·马罗尔德; S·巴斯曼
Original assignee: Voith Patent GmbH
Current assignee: Voith Patent GmbH
Priority date: 2021-03-29
Filing date: 2022-03-08
Publication date: 2023-11-14
Also published as: WO2022207248A1; DE102021107854A1

Abstract

A multi-layer forming machine for a paper, board or tissue machine for making at least three layers of paper, board or tissue, wherein the multi-layer forming machine comprises: an upper first headbox and a first screen associated with the upper first headbox for conveying a first fibrous material layer along the upper first dewatering section in the machine direction of travel, an upper second headbox and a second screen associated with the upper second headbox for conveying a second fibrous material layer along the upper second dewatering section against the machine direction of travel, a lower third headbox and a third screen associated with the lower third headbox for conveying a third fibrous material layer along the lower third dewatering section in the machine direction of travel, wherein the end points of the upper first dewatering section and the end points of the upper second dewatering section are arranged adjacent to each other and the first fibrous material layer and the second fibrous material layer merge between these two end points, wherein the end point of the lower third dewatering section is arranged below the upper second dewatering section and the third fibrous material layer merges with the third fibrous material layer in the third fibrous material layer end point of the lower dewatering section.

Description

Multi-layer forming machine

The present invention relates to a multi-layer forming machine for a paper, board or tissue machine for making at least three layers of paper, board or tissue, wherein the multi-layer forming machine comprises an upper first headbox, an upper second headbox and a lower third headbox. The first screen associated with the upper first headbox is used to convey the first fibrous material layer along the upper first dewatering section in the machine direction of travel. A second screen associated with the upper second headbox is used to convey a second fibrous material layer along an upper second dewatering section against the machine direction of travel. The terminal point of the upper first dewatering section and the terminal point of the upper second dewatering section are arranged adjacent to each other and the first and second fibrous material layers merge between these two terminal points. A third screen associated with the lower third headbox is used to convey a third fibrous material layer along the lower third dewatering section in the machine direction of travel.

Multi-layer forming machines are basically known and are often used as components of paper, board or tissue machines, which form individual fibre material layers and combine these into a multi-layer fibre material layer. For forming the fibrous material layer, a fibrous suspension, in particular a fibrous water mixture, is applied to the associated screen by means of a headbox. The screen conveys the layer of fibrous material along a dewatering section, wherein the fibrous material is formed into a tissue that constitutes the layer of fibrous material upon dewatering.

The formation of the fibrous material in the fibrous material layer and the strength of the formed fibrous material layer are also predetermined by the length of the dewatering section. In particular for producing a multi-layered fibrous web, it is necessary that the lower fibrous material layer formed by means of the lower headbox and the lower dewatering section has sufficient strength as a basis for the upper fibrous material layer fed from the upper headbox. In this case, it is expedient if the strength of the fibrous material layer is increased by an increased degree of dewatering, so that the lower dewatering section for the lower fibrous material layer is relatively longer than the corresponding upper dewatering section.

Due to the different lengths of the individual dewatering sections, but also due to the convergence in the area between the first and second fibrous material layers and the lower third fibrous material layer in the end point of the upper dewatering section, the lower third headbox is located in front of the upper first headbox in the machine running direction. The structure of the multilayer molding machine is thereby lengthened as a whole in the machine running direction. However, longer multilayer molding machines require more installation space and are therefore more expensive.

The invention aims to provide a shorter multi-layer forming machine.

The technical problem is solved by a multi-layer forming machine having the technical features of claim 1 and is characterized in particular in that the end point of the lower third dewatering section is arranged below the upper second dewatering section and in that the first and second fibrous material layers merge with the third fibrous material layer in the region of the end point of the lower third dewatering section and in the region of the couch roll. The couch roll is suitably arranged in the loop of the second screen above.

The present invention is based on the general idea of shortening the length of the multi-layer forming machine in that the joining of the first and second fibrous material layers with the lower third fibrous material layer is not carried out in the intermediate region below the end point of the upper first dewatering section and the end point of the upper second dewatering section, but is shifted in the machine running direction into the region below the second dewatering section. The on-image representation is that the end point of the lower third dewatering section moves in the machine direction below the upper second dewatering section. Thereby, the lower third headbox, which is associated with the lower third dewatering section, is also displaced in the machine direction of travel, so that the lower third headbox is seen in the machine direction closer to the upper first headbox. As a result, the length of the multilayer molding machine is shortened in the machine direction of operation, and the multilayer molding machine generally requires less space. This provides the advantage of saving costs by saving material to manufacture and by lower space requirements of the multi-layer molding machine. The shorter design of the multi-layer molding machine is particularly advantageous in that the walkways oriented in the machine direction of travel and the white water container receiving the suspension can likewise be designed in a shortened manner, thereby further reducing costs.

In the multi-layer forming machine according to the invention, there is no concern about disadvantages occurring in the formation of the paper, for example a reduction in the strength of the lower third fibre material layer, since the length of the lower third dewatering section is not changed or is only slightly changed if necessary in the event of a shift in the end point of the lower third dewatering section below the upper second dewatering section.

The start of the dewatering section is determined by the area in which the fibre suspension reaches the screen from the headbox. A region is defined as the end point of the dewatering section, in which region the fibre material layers transported along the dewatering section merge with at least one further fibre material layer.

Advantageous embodiments of the invention emerge from the dependent claims, the description and the figures.

The particularly compact construction of the multi-layer molding machine is achieved in that the upper first headbox and the lower third headbox are arranged at least almost immediately next to one another. It may also be advantageous for the compact construction of the multi-layer molding machine to have a deflection roll arranged at least almost immediately below the upper second headbox and at the end of the lower third screen.

Typically, a screen section is provided between the end point of the third dewatering section and the turning roll at the end point of the third screen below, along which screen section the multi-layered fibrous web is transported in particular towards the turning roll at the end point of the third screen below. In this case, the screen is supported against trembling movements in the region of the screen section. As the end point of the lower third dewatering section is displaced below the upper second dewatering section, the end point of the lower third dewatering section is moved in the direction of the turning roll at the end point of the lower third screen, whereby the screen section as a whole is shortened. Advantageously, there is then no need for support of the screen in the free screen section. In other words, an unsupported free screen section may be provided between the end of the third dewatering section and the turning roll at the end of the third screen below.

In the multilayer molding machines of the past, the upper first headbox and the lower third headbox are usually each supported by its own frame element. Furthermore, since the end point of the lower third dewatering section is displaced below the upper second dewatering section, the upper first headbox and the lower third headbox can be supported by a common frame element by the shortened multi-layer forming machine. Thereby requiring only one frame member and reducing costs.

For a particularly compact construction of the multi-layer molding machine, the upper first headbox and the lower third headbox on the frame member are ideally arranged vertically one above the other.

Suitably, the frame member may be used not only for accommodating the upper first headbox and the lower third headbox, but also for accommodating the first breast roll associated with the first headbox. Additionally or alternatively, the frame member may house a third breast roll associated with a third headbox. This embodiment is particularly advantageous because the breast roll is located directly below the headbox as the first roll of the screen section.

In order to achieve better accessibility during maintenance, the or each breast roller on the frame element can be rotatably supported, in particular downwards. For the downward-pivotable support of the breast roll, lockable swivel bearings or pivot bearings are preferably used.

A plurality of receiving openings for receiving a plurality of frame holders are advantageously provided in the frame component. The frame element can thus be used not only for supporting the first and third headboxes and, if appropriate, for accommodating the respective breast rolls, but also for accommodating a plurality of frame holders for holding frame parts of the multi-layer molding machine. For a particularly simple installation of the frame holders on the frame component, the receiving openings each have an opening section oriented parallel to the machine running direction. The frame holder is thereby moved in a simple manner and preferably points forward in the machine running direction for the longitudinal component of the multi-layer molding machine.

The frame member may have at least one walking area oriented substantially parallel to the mounting direction of the headbox. The walking area makes the or each headbox and/or the or each breast roll particularly easily accessible to an operator or maintenance person. Furthermore, the walking area can replace at least one transverse step with a console fastening, so that the walking area additionally assumes a stable function.

The frame element, which is preferably made of cement, in particular ultra-high strength cement or steel, is thereby sufficiently stable to carry all loads. The cement material or steel preferably has a density of 100 to 800N/mm ² Compressive strength of (a) is provided.

The frame members may also be made of both cement and steel. The frame element may in particular be a cement element reinforced by means of a steel frame.

If the frame member is made of cement, the frame member may be manufactured by means of a cement casting method. The receiving opening may be provided during the casting process.

The multi-layer molding machine is exposed to particularly humid environments due to the dewatering of the fibrous material layers. It is therefore advantageous that the cement material and/or steel material is corrosion resistant. To further increase the resistance, the cement material and/or steel may have at least one additional corrosion resistant surface. If the cementitious material and/or steel material is a non-corrosion resistant material, the cementitious material and/or steel material should have at least one corrosion resistant surface. The corrosion-resistant cement can be produced, for example, by mixing a polymer resin.

The cementitious material and/or steel material or their surfaces are also advantageously resistant to cleaning agents that are sometimes required for cleaning the multi-layer forming machine. Furthermore, the cleaning of the frame member is simplified by the frame member having a smooth surface.

A smooth cement surface is achieved, for example, by a smooth casing of a form used in pouring cement. The smooth housing can be realized, for example, by means of a plastic template or a polished metal plate. Furthermore, a smooth cover can be realized by a plywood with a film layer made of plastic, such as phenolic resin or melamine resin.

The invention also relates to a frame member for a multi-layer forming machine of a paper, board or tissue machine, in particular of the type described above, wherein the frame member supports an upper headbox and wherein the frame member supports at least one lower headbox that is independent from the upper headbox. Preferably, the upper headbox and the lower headbox are arranged at least almost immediately above each other.

The invention is described below purely by way of example with reference to the accompanying drawings in connection with possible embodiments. In the drawings:

fig. 1 shows a side view of a multilayer molding machine.

In the sole drawing figure 1 shows a multi-layer forming machine for a paper, board or tissue machine for making at least three layers of paper, board or tissue. In addition, fig. 1 also shows the press section located after the multilayer molding machine in the machine direction of travel (arrow P). Referring to fig. 1, the press section is located on the left side of the page.

The multi-layer former comprises three headboxes 10, 12, 14. Namely an upper first headbox 10, an upper second headbox 12 and a lower third headbox 14. These headboxes 10, 12, 14 are used to apply the fiber suspension to the screens 16, 18, 20 associated with the respective headbox. Excess suspension liquid, such as water, is removed from the fibrous material suspension by passing through the screens 16, 18, 20. By removing the suspension liquid, the fibre material is shaped and constitutes a further moist fibre material layer which is conveyed by means of the respective screen 16, 18, 20.

For conveying the fibrous material layer, the screens 16, 18, 20 are designed as endless screens 16, 18, 20 and are guided by means of a plurality of deflection rolls 22 and couch rolls 22' arranged in the loops of the upper second screen 18. In the region of the couch roll 22', the fibrous material layer formed on the upper screen 16, 18 is pressed against the fibrous material layer formed on the lower third screen 20. In this case, at least one deflection roller 22 or couch roller 22', which also serves as deflection roller, can be designed as an actively driven roller for conveying the individual screens 16, 18, 20. In this position, the deflection rolls 22, which are also called breast rolls 24, which are directly associated with the respective headbox 10, 12, 14 protrude. In other words, each breast roll 24 is positioned at the start point 38 of each dewatering section 26, 28, 30.

Specifically, the upper first headbox 10 is equipped with a first screen 16 that conveys the first fibrous material layer along the upper first dewatering section 26 in the machine direction of travel P. The upper second headbox 12 is provided with a second screen 18 which conveys the second fibrous material layer along an upper second dewatering section 28 against the machine direction of travel P. The lower third headbox 14 is provided with a third screen 20 which conveys a third fibrous material layer along the lower third dewatering section 30 in the machine direction of travel P. The third dewatering section 30 is arranged below the first 26 and second 28 dewatering sections, so the third dewatering section 30 is also called lower dewatering section 30, and the first 26 and second 28 dewatering sections are also called upper dewatering sections 26, 28.

Each dewatering section 26, 28, 30 comprises a plurality of dewatering boxes 32 which are arranged below the screens 16, 18, 20 containing the layers of fibrous material and collect the suspension liquid removed from the fibrous suspension.

The headbox 10, 12, 14, dewatering sections 26, 28, 30 and turning roll 22 and couch roll 22' are supported by both a vertical frame member 34 and a horizontal frame member 36.

The dewatering sections 26, 28, 30 each have their origin 38 at which the fibre suspension enters the screens 16, 18, 20 from the headbox 10, 12, 14. At the end point 40', 40", 40'" of the dewatering sections 26, 28, 30 a zone is defined in which the layers of fibrous material conveyed along the dewatering sections 26, 28, 30 converge with at least one further layer of fibrous material.

As shown in fig. 1, the terminus 40' of the first dewatering section 26 and the terminus 40 "of the second dewatering section 28 are disposed adjacent to each other. At the end points 40', 40 "of the first dewatering section 26 and the second dewatering section 28, precisely between the end points 40', 40" of the first dewatering section 26 and the second dewatering section 28, the first fibrous material layer and the second fibrous material layer meet. The joined first and second fibrous material layers further merge with the third fibrous material layer at the terminus 40' "of the third dewatering section 30 to form a three-layer fibrous web.

As also shown in fig. 1, the lower dewatering section 30 is longer than the respective upper dewatering sections 26, 28. By means of the longer lower dewatering section 30, the lower third fibre material layer has a sufficiently high strength when the already joined first and second fibre material layers from above are fed into the lower third fibre material layer.

Fig. 1 also shows that the end point 40' "of the lower third dewatering section 30 is arranged below the upper second dewatering section 28. However, by displacement of the end point 40' "of the lower third dewatering section 30, the start point of the press section after the multi-layer forming machine is not shifted. Instead, the turning roll 42 arranged in front of the press section is also at least near below the upper second headbox 12 at the end of the lower third screen. The screen section 44, which extends between the ending point 40 '"of the lower third dewatering section 30 and the turning roll 42 on the ending point of the lower third screen, shortens as a result of the displacement of the ending point 40'" of the lower third dewatering section 30 and the unchanged position of the turning roll 42 on the ending point of the lower third screen in the upper second headbox 12.

The support elements for preventing unwanted floating of the underlying third screen 20 can be omitted by the shortened screen sections 44. The lower third screen 20 is thereby conveyed unsupported along the free screen section 46. It is appreciated herein that the shortened screen section 44 for additional dewatering of the multi-layered fibrous web may have additional dewatering boxes 32.

The displacement of the end point 40' "of the lower third dewatering section 30 below the upper second dewatering section 28 also allows the upper first headbox 10 and the lower third headbox 14 to be arranged directly on top of each other, whereby the length of the multi-layer forming machine is shortened overall in the machine running direction. The upper first headbox 10 and the directly lower third headbox 14 can in particular be supported by means of a common vertical frame member 48. In this case, the first headbox 10 is arranged at least approximately vertically above the third headbox 16 on a common frame element 48.

However, the frame member 48 accommodates not only the upper first headbox 10 and the lower third headbox 16, but additionally also the first breast roll 24 associated with the first headbox 10 and the third breast roll 24 associated with the third headbox 16. In principle, however, it is also possible that the breast roll 24 can be accommodated by a frame element which is configured separately from the frame element 48 accommodating the headbox 10, 16.

For better accessibility during maintenance operations, the breast roll 24 is rotatably supported on the frame member 48. The breast roll 24 is preferably rotatable downwardly. For moving the breast roll a swivel bearing or a pivot bearing is provided. Furthermore, the breast roll 24 associated with the second headbox 12 can also be rotatably supported on a vertical frame member 34 which accommodates the second headbox 12.

The frame member 48 housing the first 10 and third 16 headboxes also has a receiving opening, not shown, for receiving the frame holder. The receiving openings each have an opening section which is oriented parallel to the machine direction of travel P.

Furthermore, a walking area, which is not visible in fig. 1, is provided on the frame member 48 accommodating the first 10 and third 16 headboxes, which walking area is oriented substantially parallel to the mounting direction of the headboxes 10, 16. The walking area is used to provide better access to the headboxes 10, 16 and breast roll 24. Furthermore, the walking area replaces at least one lateral step and thereby helps stabilize the frame member 48.

The frame members 48 of the multi-layer forming machine housing the first 10 and third 16 headboxes and the remaining vertical and horizontal frame members 34, 36 are made of corrosion resistant cement or corrosion resistant steel to cope with the humid environmental conditions in the region of the multi-layer forming machine. The cement material or steel has at least one corrosion-resistant surface.

Furthermore, the corrosion resistance of the cement material or steel is advantageous when the frame members 34, 36, 48 are cleaned by a cleaning agent. The smooth surface of the frame members 34, 36, 48 also simplifies cleaning of the multi-layer molding machine.

List of reference numerals

10. Upper first headbox

12. Upper second headbox

14. Third flow box below

16. A first screen above

18. A second screen above

20. A third screen below

22. Steering roller

22' couch roll

24. Chest roll

26. A first dewatering section above

28. A second dewatering section above

30. A third dewatering section below

32. Dewatering box

34. Vertical frame member

36. Horizontal frame member

38. The starting points of the dewatering sections 26, 28, 30

End of the first dewatering section 26 above 40

40 "end of the second dewatering section 28 above

40' "below the end point of the third dewatering section 30

42. Turning roll at the end point of the lower third screen

44. Screen section

46. Free screen section

48. Frame component

P machine direction of travel

Claims

1. A multi-layer forming machine for a paper, board or tissue machine for making at least three layers of paper, board or tissue, wherein the multi-layer forming machine comprises:

-an upper first headbox (10) and a first screen (16) associated with the upper first headbox (10) for transporting a first fibrous material layer along an upper first dewatering section (26) in a machine direction of travel (P),

-an upper second headbox (12) and a second screen (18) associated with the upper second headbox (12) for conveying a second fibrous material layer along an upper second dewatering section (28) against the machine running direction (P),

-a lower third headbox (14) and a third screen (20) associated with the lower third headbox (14) for conveying a third fibrous material layer along a lower third dewatering section (30) in a machine running direction (P), wherein the ending point (40 ') of the upper first dewatering section (26) and the ending point (40 ') of the upper second dewatering section (28) are arranged adjacent to each other and the first fibrous material layer and the second fibrous material layer merge between these two ending points (40 ' ),

characterized in that the end point (40 ') of the lower third dewatering section (30) is arranged below the upper second dewatering section (28) and that the first and second fibrous material layers merge with the third fibrous material layer in the region of the end point (40 ') of the lower third dewatering section (30) and in the region of the couch roll 22 '.

2. A multi-layer moulding machine according to claim 1, characterized in that the upper first headbox (10) and the lower third headbox (14) are arranged at least almost immediately adjacent to each other.

3. The multi-layer forming machine according to at least one of the preceding claims, characterized in that a turning roll (42) is arranged at the end point of the third screen below at least almost immediately below the second headbox (12) above.

4. Multi-layer forming machine according to at least one of the preceding claims, characterized in that an unsupported screen section (46) is provided between the end point (40' ") of the lower third dewatering section (30) and the turning roll (42) at the end point of the lower third screen.

5. The multi-layer forming machine according to at least one of the preceding claims, characterized in that the upper first headbox (10) and the lower third headbox (14) are supported by a common frame member (48).

6. A multi-layer moulding machine according to claim 5, characterized in that the upper first headbox (10) and the lower third headbox (14) on the frame element (48) are arranged at least almost vertically above each other.

7. The multi-layer forming machine according to claim 5 or 6, characterized in that the frame member (48) accommodates a first breast roll (24) assigned to the upper first headbox (10) and/or that the frame member (48) accommodates a third breast roll (24) assigned to the lower third headbox (14).

8. A multi-layer moulding machine according to claim 7, characterized in that the or each breast roll (24) on the frame member (48) is rotatably supported, in particular downwards.

9. The multi-layer molding machine according to any one of claims 5 to 8, wherein a plurality of receiving openings for receiving frame holders are provided in the frame member (48), in particular wherein the receiving openings each have an opening section oriented parallel to the machine running direction (P).

10. The multi-layer forming machine according to any one of claims 5 to 8, characterized in that the frame member (48) has at least one walking area which is oriented substantially parallel to the mounting direction of the headbox (10, 14).

11. The multilayer forming machine according to any one of claims 5 to 10, characterized in that the frame member (48) is made of cement and/or steel.

12. The multilayer moulding machine according to claim 11, characterized in that the cement material and/or the steel material is corrosion-resistant and/or that the cement material and/or the steel material has at least one corrosion-resistant surface.

13. The multi-layer molding machine according to any one of claims 5 to 12, wherein the frame member (48) has a smooth surface.

14. A frame member (48) for a multi-layer forming machine of a paper, board or tissue machine, in particular according to any of the preceding claims, wherein the frame member (48) supports an upper headbox (10), characterized in that the same frame member (48) supports at least one lower headbox (16) independent from the upper headbox (10), in particular wherein the upper headbox (10) and the lower headbox (16) are arranged at least almost immediately next to each other.