Pressing body for paper machine and paper machine

Abstract

The invention relates to a press body for a paper machine having an extended press zone formed between the press body and a counter pressure member wherein the press body is elastically deformable and comprises a working surface, and wherein the press body comprises a first pressure chamber and a second pressure chamber, the first and second pressure chambers are arranged inside the press body and separated from each other by a partition wall, said pressure chambers being configured to be pressurized such that the press body expands for pressing the working surface towards the counter pressure member, and wherein the partition wall between the first and second pressure chambers has a wall thickness of 1 mm to 20 mm. The invention also relates to a paper machine comprising at least one press body.

Description

Technical Field

[0001] This invention relates to a press body for a paper machine having an extended pressure zone formed between the press body and a counter-pressure member, the press body including an internal pressure chamber. The invention also relates to a paper machine having such a press body. Background Technology

[0002] In papermaking machines, stretch press treads are typically used to press water out of newly formed wet fiber webs, but they can also be used for other purposes, such as calendering. Although stretch press treads were first introduced for heavy paper grades such as paperboard, they have also begun to be used for light paper grades such as printing paper, and even for tissue paper. When manufacturing tissue paper, the stretch press tread is typically formed by stretch press rolls and Yankee dryers that act as the reverse pressure members of the stretch press rolls.

[0003] Especially in machines used for manufacturing tissue paper, the stretch press clump is typically formed by a stretch press roll, which includes a support body with a working surface that is pressed against a counter roll via a pressure chamber located inside or below the support body. This pressure chamber is used to push the support body toward the counter roll in a first direction. The purpose of the stretch press clump is to dewater the fiber web during papermaking.

[0004] In the art, rigid support bodies, typically made of metallic materials, are known. However, because rigid support bodies are non-flexible, it is difficult to achieve the desired pressure distribution in the stretching press, which hinders the effective dewatering of the fiber web and leads to excessive wear of components of the stretching press, such as the stretching press rollers and the felt used to transport the web through the press.

[0005] Therefore, a softer, more flexible support body capable of elastic deformation is preferred, and dehydration can be significantly improved by achieving the desired pressure distribution against the reverse pressure member. The flexible support body typically includes at least two pressure chambers housed within the support body, and by pressurizing the pressure chambers, the working surface is pressed against the reverse pressure member.

[0006] However, a challenging aspect of designing and operating flexible support bodies is maintaining stability when the pressure chambers are pressurized independently. Due to the flexible material, the support body tends to deform in unpredictable ways, thereby distorting the pressure distribution and reducing dehydration efficiency. There is also a risk of plastic deformation due to excessive pressure in one or more pressure chambers, which could damage the support body.

[0007] Therefore, improvements are needed in this area. Summary of the Invention

[0008] The object of the present invention is to eliminate or at least minimize the aforementioned problems. This is achieved by the press body for a paper machine and the paper machine according to the appended independent claims.

[0009] The press body of the present invention is applicable to papermaking machines having an extended press zone formed between the press body and a reverse pressure member. The press body itself is elastically deformable and includes a working surface, and further includes a first pressure chamber and a second pressure chamber disposed within the press body and separated from each other by a partition wall. The pressure chambers are configured to be pressurized, causing the press body to expand in order to press the working surface against the reverse pressure member. Furthermore, the partition wall between the first and second pressure chambers has a wall thickness of 1 mm to 20 mm.

[0010] By providing partition walls with a thickness of at least 1 mm, stability is ensured to prevent breakage of the partition walls when the pressure chamber is pressurized. Furthermore, by providing partition walls with a thickness of 20 mm or less, the flexibility of the support body is ensured, allowing the pressure chamber to expand as expected when pressurized.

[0011] The chamber wall suitably has a thickness of 1 mm to 12 mm, preferably 4 to 6 mm, and more preferably 4 mm. This achieves a balance between flexibility and rigidity, stabilizing the partition wall while simultaneously allowing it to stretch to expand the press body. The inventors have found that a wall thickness of 4-6 mm is particularly advantageous, and that a wall thickness of 4 mm provides flexibility to the partition wall while reducing the risk of undesirable deformation and breakage.

[0012] The first and second pressure chambers are suitably configured to be pressurized independently of each other, and the first pressure chamber includes a support element for supporting the partition wall, the height of which corresponds to the height of the first pressure chamber. Therefore, the support element provides support for the partition wall and prevents undesirable deformation.

[0013] Appropriately, the first pressure chamber has a first height, and the second pressure chamber has a second height. Furthermore, the first height can be at least equal to the sum of the second height and the maximum stroke length of the pressing body. Therefore, deformation of the partition wall between the first and second pressure chambers is prevented even at the maximum stroke.

[0014] The maximum stroke length can be at least 4 mm, preferably at least 8 mm, and more preferably at least 10 mm. Therefore, the press body can expand to meet the requirements of the paper machine in which it is arranged. Furthermore, the expansion of the press body can be achieved by stretching the partition walls between the pressure chambers due to the increased pressure inside the pressure chambers.

[0015] In some embodiments, the maximum stroke length is at least 15 mm, preferably at least 20 mm, and more preferably at least 30 mm. Thus, a very large stroke is achieved, and the partition wall is configured to stretch to accommodate this. It is highly advantageous that the stretching of the partition wall is performed to extend the press body without excessive energy absorption, thereby ensuring the desired pressure distribution in the extended press zone.

[0016] Appropriately, the bottom of the first pressure chamber is located at the height of the bottom of the first chamber in the pressing body, and the bottom of the second pressure chamber is located at the height of the bottom of the second chamber in the pressing body. Furthermore, the height of the bottom of the second chamber is appropriately equal to or greater than the sum of the height of the bottom of the first chamber and the maximum stroke length. Therefore, the pressing body can expand to its maximum stroke length without the partition wall at the bottom of the first pressure chamber deforming into the first pressure chamber. This helps prevent plastic deformation or damage to the partition wall at the bottom when the pressure chambers are pressurized.

[0017] Furthermore, the top of the first pressure chamber is appropriately located at the height of the top of the first chamber in the pressing body, and the top of the second pressure chamber is located at the height of the top of the second chamber in the pressing body. Moreover, the height of the top of the first chamber can be equal to or greater than the sum of the height of the top of the second chamber and the maximum stroke length. Thus, the pressing body can expand to its maximum stroke length without the partition wall at the top of the first pressure chamber deforming into the first pressure chamber. This helps prevent plastic deformation or damage to the partition wall at the top when the pressure chamber is pressurized.

[0018] Appropriately, the shape of the support element corresponds to the shape of the partition wall in the first pressure chamber. Therefore, the support element can support the partition wall by following it to prevent a portion of the partition wall from being pushed into deformation within the first pressure chamber. Conversely, when the press body is used in a paper machine, the partition wall is guided to stretch and expand in the direction of entering the extension press zone.

[0019] In some embodiments, the wall thickness of the partition wall is substantially constant. Therefore, uniform strength of the partition wall is achieved.

[0020] In other embodiments, the partition wall gradually narrows from a maximum width to a minimum width, and the wall thickness is at the minimum width. Therefore, the partition wall is reinforced where additional support is expected to be needed to ensure the desired tensile strength of the partition wall while preventing undesirable deformation into the first pressure chamber.

[0021] In embodiments where the partition wall gradually narrows, the partition wall appropriately has its maximum width at the upper end of the first pressure chamber and / or the second pressure chamber. Therefore, the upper end of the partition wall is reinforced and better able to resist unwanted deformation entering the first pressure chamber. This is particularly advantageous in terms of stabilizing the partition wall, as deformation tends to increase at the upper end of the first pressure chamber.

[0022] Alternatively, in embodiments where the partition wall gradually narrows, the partition wall may have its maximum width at the lower end of the first pressure chamber and / or the second pressure chamber. Therefore, the lower end of the partition wall is reinforced and better able to resist unwanted deformation entering the first pressure chamber. This is particularly advantageous in terms of stabilizing the partition wall, as deformation tends to increase at the lower end of the first pressure chamber.

[0023] Furthermore, in some embodiments, the partition wall may have its maximum width at both the upper and lower ends of the first and / or second pressure chambers, gradually narrowing to its minimum width in the middle portion between the upper and lower ends. Therefore, both the upper and lower ends of the partition wall are supported to prevent undesirable deformation and to stabilize the partition wall.

[0024] The present invention also relates to a papermaking machine comprising at least one press body according to any embodiment of the present invention.

[0025] The many additional benefits and advantages of the present invention will be readily apparent to those skilled in the art from the following detailed description. Attached Figure Description

[0026] The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 A schematic cross-sectional view of an extended press zone of a paper machine is disclosed, wherein the extended press zone is formed between the press body and the reverse pressure member; Figure 2 A schematic cross-sectional view of the pressing body as seen from the side according to the first embodiment of the present invention is disclosed; Figure 3 A schematic cross-sectional view of the pressing body as seen from the side according to a second embodiment of the present invention is disclosed; Figure 4 A schematic cross-sectional view of the pressing body as seen from the side according to a third embodiment of the present invention is disclosed; Figure 5A schematic cross-sectional view of the pressing body as seen from the side according to the fourth embodiment of the present invention is disclosed; Figure 6 A schematic cross-sectional view of the pressing body as seen from the side according to the fifth embodiment of the present invention is disclosed; Figure 7 A schematic cross-sectional view of the press body as seen from the side according to the sixth embodiment of the present invention is disclosed; and Figure 8 A schematic cross-sectional view of the pressing body as seen from the side according to the seventh embodiment of the present invention is disclosed.

[0027] All accompanying drawings are schematic and not necessarily to scale, and generally only show the parts necessary to explain the corresponding embodiments, while other parts may be omitted or are merely suggested. Unless otherwise indicated, any reference numerals appearing in multiple figures refer to the same object or feature in all figures. Detailed Implementation

[0028] When the term "papermaking machine" is used herein, it should be understood as a machine suitable for producing paper from pulp. This machine can be configured to produce tissue paper, but it can also be configured to produce writing paper or paperboard. In the following text, the production of tissue paper is mentioned, but this is considered merely as an example and not as a limitation on the scope of the invention.

[0029] When terms such as “upper,” “lower,” “top,” and “bottom” are used below, they should be understood to relate to a first direction D, which can be considered an upward direction. Therefore, the upper side is the side facing the first direction D, while the lower side faces the direction opposite to the first direction D. Furthermore, the upper and lower parts are distinguished from each other by the movement towards the first direction D first passing through the bottom and then through the upper part.

[0030] It should be noted that all dimensions given in this document should be understood as being within manufacturing tolerances, or at least with a variation of no more than 10%. Furthermore, when a characteristic is described as substantially constant or substantially uniform, this should also be understood as remaining constant or uniform within manufacturing tolerances, or at least with a variation of no more than 10%.

[0031] Figure 1 An extended press zone N of a paper machine 1 is disclosed, wherein the extended press zone N is formed between the press body 50 and the reverse pressure member 7 according to the invention.

[0032] A paper machine comprising an extension press N having a press body 50 according to the invention will now be described, with the description focusing on the extension press N and only a brief description of the other parts of the paper machine.

[0033] Therefore, as is known in the art, paper machines typically include a forming section in which a headbox is arranged to inject pulp into the gap between the forming fabric and the felt 33. The forming fabric is typically a foraminouswire. The felt is configured to pass through the forming roll, and the felt and the forming fabric are guided into a loop by guide rolls.

[0034] The newly formed wet fiber web is transported from the forming section by felt 33 to... Figure 1 The extended pressing zone N shown is formed between the extended pressing roller 5 and the reverse pressure member 7. The extended pressing roller 5 includes a pressing body 50 according to the invention, which will be described in further detail below. The reverse pressure member 7 may suitably be a Yankee dryer, but in some embodiments, the extended pressing zone may be arranged between the extended pressing roller 5 and another reverse pressure member 7 before being conveyed to the Yankee dryer.

[0035] In the press zone N between the stretch press rolls and the reverse pressure member 7, water is pressed out from the web W and absorbed by the felt 33 used to receive water. The web W then passes through a Yankee dryer 7 and is dried by heat spreading from the Yankee dryer 7 to the web W. The Yankee dryer 7 is typically heated to a temperature of approximately 95-100 °C on the surface in contact with the web W. The dry solids content of the web W upon reaching the stretch press zone N can vary significantly, but in typical applications, it is in the range of 18-30%. Depending on factors such as the linear load in the press zone, the temperature of the reverse pressure member 7, and the dry solids content of the web W before reaching the stretch press zone N, the web W can have a dry solids content of 40-55% after the stretch press zone N.

[0036] The web material W is typically scraped off from the Yankee dryer 7 by a doctor blade and then fed to the rewinder as dried web material.

[0037] The above description is considered a general description of the paper machine 1. However, it should be noted that the press body 50 according to the invention can be used in various paper machines, as long as the paper machine has an extended press zone between the press body and the reverse pressure member.

[0038] Now we will refer to it again. Figure 1 The extended press zone N is described in more detail. The figure shows an extended press roll 5, which includes a flexible sheath 10 having an inner surface 11 and an outer surface 12. The flexible sheath 10 typically comprises polyurethane and is shaped as a tube extending in the machine transverse direction, which is a direction perpendicular to the machine direction defined as the direction from the forming section to the winding machine, i.e., the main travel direction of the web W.

[0039] Therefore, the axial direction of the flexible sleeve 10 is aligned with the transverse direction of the machine, and the flexible sleeve 10 is typically connected to an end wall at its axial end, which is rotatably arranged about an axis, allowing the extension pressing roller 5 to rotate. Suitable, the extension pressing roller 5 can be connected to a pressurized air source, so that the enclosed space formed by the flexible sleeve 10 and the end wall can be filled with pressurized air.

[0040] Inside the extended pressing roller 5, a support member 21 is installed, which holds the pressing body 50 according to the invention such that the upper surface 14 of the support body 50 presses against the inner surface 11 of the flexible sheath 10. Working surface 15 (see below) Figure 2 Located on the upper surface 14, this working surface forms an extended press zone N by pressing against the flexible sheath 10, such that the web W presses against the reverse pressure member 7. The press body 50 is elongated and extends along the inner surface 11 of the extended press roller 5 in a direction transverse to the rotation direction of the extended press roller 5, so as to press against the entire width of the web W in the extended press zone N. For this purpose, the length of the press body 50 may be equal to or greater than the target width of the web W, but in some embodiments, the length of the press body 50 may alternatively be shorter than the target width of the web W.

[0041] The working surface 15 is a surface used to form the extended press zone N. The shape of the working surface 15 can be adapted to form a desired press distribution with the reverse pressure member 7, as is known in the art. A prior art design for processing the working surface is US2009 / 0173465 (Metso Paper).

[0042] The following will be from Figure 2 The first embodiment shown begins with a detailed description of the press body 50. For other embodiments of the invention, features that differ from one another will be described primarily to avoid repetition. Therefore, it should be understood that all features not specifically described as different between different embodiments should be considered similar or identical. Moreover, features from one embodiment can be freely combined with those in another technically feasible embodiment.

[0043] The press body 50 includes a first pressure chamber 51 and a second pressure chamber 52 separated from each other by a partition wall 53. Each of the first pressure chamber 51 and the second pressure chamber 52 is configured to be pressurized by fluid connection to a pressurized fluid source, as known in the art. The pressurized fluid is suitably a hydraulic fluid (e.g., oil), but in some embodiments other fluids may be used instead.

[0044] The press body 50 is made of an elastically deformable material, which causes the press body 50 to expand when the first pressure chamber 51 and the second pressure chamber 52 are pressurized. During use, the press body 50 is mounted in the support 21 (see...). Figure 1 The pressing body 50 can mainly follow the Figure 2 The pressure chamber expands in the first upward direction D. This expansion causes the working surface 15 on the upper side of the press body 50 to be pressed against the reverse pressure member 7, thereby forming a pressure zone N. The partition wall 53 between the first pressure chamber 51 and the second pressure chamber 52 has a wall thickness t of 1 mm to 20 mm.

[0045] Preferably, the press body 50 is elastically deformable by being made of a material having a Shore A hardness of 50-100, preferably 80-100, and more preferably 90-95. When Shore A hardness is mentioned herein, it will be understood according to ASTM D2240. The press body 50 may also comprise more than one material, wherein at least one material has a Shore A hardness as described above. A suitable material is polyurethane.

[0046] As the press body 50 expands, the partition wall 53 stretches as the height of the first pressure chamber 51 and the second pressure chamber 52 increases. For the press body of the present invention, it is highly advantageous that the partition wall 53 is at least 1 mm thick, as this allows stretching without the risk of breakage of the partition wall 53. Furthermore, a maximum thickness of 20 mm for the partition wall 22 is advantageous, because stretching a thicker wall would result in increased load and thus a loss of pressure that the working surface 15 can exert in the pressing zone N. The inventors have discovered that the thickness t of the partition wall 53 allows expansion without breakage or plastic deformation, while minimizing losses.

[0047] The press body 50 of the first embodiment can alternatively have a thickness of 1 mm to 12 mm, thereby further minimizing losses during the expansion of the press body 50. Particularly advantageously, the thickness t of the partition wall 53 is 4 mm to 6 mm, and even more advantageously, t is 4 mm. This has been found to be very suitable for stretching to the maximum stroke of the press body 50 while minimizing losses.

[0048] The pressure inside the first pressure chamber 51 can be equal to the pressure inside the second pressure chamber 52, or alternatively, they can be different. Particularly advantageous when a specific pressure distribution is required in the pressing zone N is desired, is to have a lower pressure in the first pressure chamber 51 and a higher pressure in the second pressure chamber 52. Thus, the press body 50 is arranged in the machine direction such that the second pressure chamber 52 is located after the first pressure chamber 51, so that when the web W moves through the pressing zone N, the web is first subjected to pressure from the first pressure chamber 51, and then to pressure from the second pressure chamber 52.

[0049] exist Figure 2In the first embodiment, the first pressure chamber 51 and the second pressure chamber 52 have the same or similar dimensions (e.g., cross-sectional shape and volume) and are configured to be pressurized individually to different pressures or together to similar or the same pressures.

[0050] Figure 3 A second embodiment of the present invention is disclosed, which differs from the first embodiment in that the first pressure chamber 51 is larger than the second pressure chamber 51, and a support element 54 is provided in the first pressure chamber 51. The height of the support element 54 corresponds to the first height h1 of the first pressure chamber 51, such that the support element 54 extends from the bottom to the top of the first pressure chamber 51. Figure 3 In this embodiment, the support element 54 is shown only along the partition wall 54, but in some embodiments, the support element 54 may alternatively have other shapes and designs, as long as it can support the partition wall 53 and prevent stretching or deformation in directions other than the first direction D (see, for example, [reference needed]). Figure 4 Especially when the first pressure chamber 51 and the second pressure chamber 52 are individually pressurized such that the first pressure chamber 51 is at a lower pressure than the second pressure chamber 52, the support element 54 is advantageous in preventing such deformation. In the above case, the partition wall 53 risks deforming in the lateral direction from the second pressure chamber 52 toward the first pressure chamber 51 (i.e., in the direction perpendicular to the first direction D). When using the press body 50, the expansion caused by the pressurized pressure chambers 51, 52 should occur only in the first direction D, and when the press body 50 is placed in the retainer 21 of the paper machine 1, the support element 54 ensures that this is the only available direction.

[0051] Furthermore, the first pressure chamber 51 has a first height h1, and the second pressure chamber 52 has a second height h2. Figure 3 In the second embodiment, the first height h1 is at least equal to the sum of the second height h2 and the maximum stroke length SL of the press body 50. This means that the press body 50 can extend its maximum stroke length SL in the first direction D, while the second pressure chamber 52 does not extend beyond the first height h1, and since the first height corresponds to the height of the support element 54, there will be support for the partition wall 53 even at the maximum stroke length SL. This is highly advantageous in protecting the partition wall 53, thereby increasing the lifespan of the press body 50 and reducing the need for maintenance.

[0052] In the second embodiment, the first pressure chamber 51 has a bottom b1 located at a first chamber bottom height bh1 in the pressing body 50, and the second pressure chamber 52 has a bottom b2 located at a second chamber bottom height bh2. The second chamber bottom height bh2 is equal to or greater than the sum of the first chamber bottom height b1 and the maximum stroke length SL. This means that if the expansion of the pressing body 50 causes the second pressure chamber 52 to expand at the bottom b2, the support element 54 will be able to support the partition wall 53 and prevent deformation from entering the first pressure chamber 51.

[0053] In all embodiments of the invention, it is advantageous for the shape of the support element 54 to correspond to the shape of the partition wall 53, as this allows for reliable support of the partition wall 53.

[0054] Figure 4 A third embodiment is shown, which differs from the second embodiment in that the top t1 of the first pressure chamber 51 is located at a height th1 of the first chamber top in the pressing body 50. The top t2 of the second pressure chamber 52 is located at a height th2 of the second chamber top in the pressing body 50, such that the height th1 of the first chamber top is equal to or greater than the sum of the height th2 of the second chamber top and the maximum stroke length SL. This means that if the expansion of the pressing body 50 causes the second pressure chamber 52 to expand at the top t2, the support element 54 will be able to support the partition wall 53 and prevent deformation from entering the first pressure chamber 51.

[0055] The third embodiment also illustrates a different design for the support element 54, namely, by extending the support element along the partition wall 53 and along the opposing wall of the first pressure chamber 51, and by using spacers that maintain a fixed distance between the support element 54 and these two walls, thereby further increasing stability at the partition wall 53. This facilitates maintaining the alignment of the support element 54 along the partition wall 53, regardless of how the partition wall 53 moves during the expansion of the press body 50.

[0056] Aside from the design of the support element 54, the main difference between the second and third embodiments lies in the placement of the first pressure chamber 51 and the second pressure chamber 52 relative to each other. This depends on whether the elongation of the partition wall 53 occurs at the top t1, t2 or at the bottom b1, b2 of the pressure chambers 51, 52. Figure 3 and Figure 4 The embodiment is able to prevent lateral deformation of the partition wall due to the height difference between the first pressure chamber 51 and the second pressure chamber 52 and their arrangement relative to each other.

[0057] Figure 5A fourth embodiment is disclosed, in which the advantages of the second and third embodiments are combined, wherein the height difference between the first pressure chamber 51 and the second pressure chamber 52 is such that the first height h1 is at least equal to the second height h2 plus twice the maximum stroke length SL. This means that elongation or stretching of the partition wall 53 can occur at the top or bottom or both, without the risk of the partition wall 53 deforming into the first pressure chamber 51, because the support element 54 will be able to cover the elongation or stretching.

[0058] In all embodiments of the present invention, the maximum stroke length SL is at least 4 mm to ensure that the press body 50 can expand into the press zone N as needed. Preferably, the maximum stroke length SL is at least 8 mm, more preferably at least 10 mm. Providing a longer maximum stroke length increases the versatility of the press body 50, as it can be designed for use in different papermaking machines producing different grades of tissue paper or paper. More preferably, the maximum stroke length is at least 15 mm, more preferably at least 20 mm, and even more preferably at least 30 mm. This ensures that the press body 50 can be used in a variety of papermaking machines for producing any kind of web from lignocellulosic materials.

[0059] By selecting the dimensions of the first pressure chamber 51 and the second pressure chamber 52 to ensure that the partition wall 53 can be stretched to the desired maximum stroke length without damage, a design is achieved that enables the press body 50 to perform a longer maximum stroke length SL. When the press body 50 is used in the paper machine 1, the desired stroke is achieved by pressurizing the first pressure chamber 51 and the second pressure chamber 52.

[0060] In all the embodiments disclosed above, the wall thickness t is shown to be substantially constant along the partition wall 53.

[0061] Figures 6 to 8 An embodiment different from the above embodiment is disclosed, wherein the width of the partition wall ranges from the maximum width w. max Change to minimum width w min In all these embodiments, the wall thickness t as used herein is understood to be the minimum width w of the partition wall 53. min Of all the other features, Figures 6 to 8 The embodiments may be similar to or the same as any other embodiments shown herein. Therefore, although in Figures 6 to 8 The diagram shows that the first pressure chamber 51 and the second pressure chamber 52 have substantially the same height, and they can also be like... Figures 3 to 5 They have different heights, just like in the middle. And, in Figures 6 to 8In any embodiment, a support element 54 may be present, and the support element 54 may have any suitable orientation or alignment in the first pressure chamber 51, as long as it can support the partition wall 53.

[0062] exist Figure 6 In the fifth embodiment of the press body 50 shown, the partition wall 53 has its maximum width w at the upper end or even at the top of the first pressure chamber 51. max And it gradually narrows towards the bottom. Advantageously, it provides improved support at the top where the elongation of the partition wall 53 during use of the press body 50 could lead to deformation or breakage of the partition wall 53. In the fifth embodiment, the partition wall 53 gradually narrows only in the first pressure chamber 51, such that the first pressure chamber 51 has a width that increases from top to bottom, while the second pressure chamber 52 has a substantially constant width. Alternatively, the partition wall may alternatively narrow only in the second pressure chamber 52 or in both the first pressure chamber 51 and the second pressure chamber 52, such that both have varying widths.

[0063] Figure 7 A sixth embodiment is disclosed, wherein the partition wall 53 has its maximum width w at the lower end or even the bottom of the first pressure chamber 51 and the second pressure chamber 52. max And it gradually narrows towards the top. This provides increased support at the bottom. Moreover, the sixth embodiment shows that both the first pressure chamber 51 and the second pressure chamber 52 have varying widths, but in some alternatives, one of them may instead have a constant width.

[0064] Figure 8 A seventh embodiment is disclosed, which combines the advantages of the fifth and sixth embodiments by providing a partition wall 53 that has a maximum width at both the top and bottom ends and gradually narrows toward the middle portion between the top and bottom. This provides the advantage of reinforcing the partition wall 53 at both the top and bottom.

[0065] It should be noted that the features from the various embodiments described herein can be freely combined unless explicitly stated that such combination is inappropriate.

Claims

1. A press body for a papermaking machine having an extended nip formed between the press body and a counter pressure member, wherein, The pressing body (50) is elastically deformable and includes a working surface (15), wherein the pressing body includes a first pressure chamber (51) and a second pressure chamber (52), the first pressure chamber and the second pressure chamber are arranged inside the pressing body (50) and separated from each other by a partition wall (53), the pressure chambers (51, 52) are configured to be pressurized such that the pressing body (50) expands to press the working surface (15) against the reverse pressure member, and wherein the partition wall (53) between the first pressure chamber (51) and the second pressure chamber (52) has a wall thickness (w) of 1 mm to 20 mm.

2. The press body of claim 1, wherein, The chamber wall (53) has a wall thickness (w) of 1 mm-12 mm, preferably 4-6 mm, and more preferably 4 mm.

3. The press body of claim 1 or 2, wherein, The first pressure chamber (51) and the second pressure chamber (52) are configured to be pressurized independently of each other, and wherein the first pressure chamber (51) includes a support element (54) for supporting the partition wall (53), the height (h) of the support element (54) corresponding to a first height (h1) of the first pressure chamber.

4. The press body of claim 3, wherein, The second pressure chamber (52) has a second height (h2), and wherein the first height (h1) is at least equal to the sum of the second height (h2) and the maximum stroke length (SL) of the press body (50).

5. The pressing body according to claim 4, wherein, The maximum stroke length (SL) is at least 4 mm, preferably at least 8 mm, and more preferably at least 10 mm.

6. The pressing body according to claim 5, wherein, The maximum stroke length (SL) is at least 15 mm, preferably at least 20 mm, and more preferably at least 30 mm.

7. The pressing body according to any one of claims 4 to 6, wherein, The bottom (b1) of the first pressure chamber (51) is located at the bottom height (bh1) of the first chamber in the pressing body, and the bottom (b2) of the second pressure chamber (52) is located at the bottom height (bh2) of the second chamber in the pressing body (50), wherein the bottom height (bh2) of the second chamber is equal to or greater than the sum of the bottom height (bh1) of the first chamber and the maximum stroke length (SL).

8. The pressing body according to any one of claims 4 to 7, wherein, The top (t1) of the first pressure chamber (51) is located at the first chamber top height (th1) in the pressing body (50), and the top (t2) of the second pressure chamber (52) is located at the second chamber top height (th2) in the pressing body (50), and the first chamber top height (th1) is equal to or greater than the sum of the second chamber top height (th2) and the maximum stroke length (SL).

9. The pressing body according to any one of claims 3 to 8, wherein, The shape of the support element (54) corresponds to the shape of the partition wall (53) in the first pressure chamber (51).

10. The pressing body according to any one of the preceding claims, wherein, The wall thickness (t) of the partition wall (53) is substantially constant.

11. The pressing body according to any one of claims 1 to 9, wherein, The partition wall (53) gradually narrows from its maximum width to its minimum width, and the wall thickness (t) is the minimum width.

12. The pressing body according to claim 11, wherein, The partition wall (53) has the maximum width at the upper end of the first pressure chamber (51) and / or the second pressure chamber (52).

13. The pressing body according to claim 11, wherein, The partition wall (53) has the maximum width at the lower end of the first pressure chamber (51) and / or the second pressure chamber (52).

14. The pressing body according to claim 11, wherein, The partition wall (53) has the maximum width at both the upper and lower ends of the first pressure chamber (51) and / or the second pressure chamber (52), and gradually narrows to the minimum width in the middle portion between the upper and lower ends.

15. A paper machine (1) comprising at least one press body (50) according to any one of the preceding claims.

Images