CN113699821A

CN113699821A - Lining roller

Info

Publication number: CN113699821A
Application number: CN202110542751.6A
Authority: CN
Inventors: 维莱·埃罗宁; 塞波·库皮艾宁; A·米蒂宁; T·西洛玛; 约尔马·斯内尔曼; 尤哈·温帕里
Original assignee: Valmet Technologies Oy
Current assignee: Valmet Technologies Oy
Priority date: 2020-05-20
Filing date: 2021-05-19
Publication date: 2021-11-26
Anticipated expiration: 2041-05-19
Also published as: CN113699821B; EP3913134A1

Abstract

A bushing roller (1) comprising: an axle beam (11) having a journal (13), the journal (13) being supported in a bearing structure (21); a roller head (31) configured to support a belt (41) tensioned around the axle beam (11) in the form of a belt loop and rotatable around the axle beam; a belt (41) rotatable about the axle beam (11) and rotatable relative to the axle beam; and a movable forming element (119) configured to protrude from the axle beam (11) so as to abut against the belt (41) to change the cross-sectional shape of the belt loop.

Description

Lining roller

Technical Field

The present invention relates to a sleeve roller. Such a bushing roll is usually arranged in the forming section of a fiber web forming machine, such as a paper, board, toilet or pulp machine.

Background

A prior art lining roller is known, for example, from document DE3142045a 1. Here, a lining arrangement (sleeve arrangement) with fixed sector support shoes/beams is arranged in the forming section of a paper or board machine. The forming section comprises two webs, each forming a closed loop. The two wires are guided such that they run in an adjacent manner along a portion of the liner arrangement with a fixed sector supporting shoe/beam circumference, forming a fabric wrap (fabric wrap) with the web sandwiched between the wires. Thus, the bushing arrangement with fixed sector support shoes/beams results in a minimum distance between the two wires, resulting in dewatering of the web located between the two wires.

Another forming section is known from document EP2350385B1, which is similar to the forming section in DE3142045a1, but which comprises a lining roller with a cross section with a varying radius of curvature. This shape enables to improve the dewatering pressure caused by the change of the radius of curvature of the lining roll.

Typically, the bushing roller includes a stationary portion, such as a beam, for supporting the belt for rotation about the beam. The belt is driven by a wire that travels around a portion of the lining roller sliding surface. Therefore, a friction problem occurs, and particularly, a static friction force is generated during the start, a static friction force and a sliding friction force are generated in the slow traveling mode, and a sliding friction force is mainly generated in the normal traveling mode.

There is a need for a bushing roller that can handle the frictional forces in different travel modes.

Disclosure of Invention

According to the invention, a lining roller (1) comprises a shaft beam (11) with a shaft journal (axle stub). The journal (13) is supported in a bearing structure (21). Furthermore, the lining roller comprises a roller head (31) which is configured to support a belt (41) which is tensioned around the axle beam (11) in the form of a belt loop and can rotate around the axle beam. The belt (41) is rotatable about and relative to the axle beam (11). The movable forming element (119) is configured to protrude from the axle beam (11) so as to abut against the belt (41) to change the cross-sectional shape of the belt loop.

Thus, by means of the movable forming elements, the shape of the band running around the axle and corresponding to the circumference of the roller head can be changed to have projections, wherein the movable forming elements project. The protrusion can be achieved even during operation of the paper or board machine. Thus, the start-up time can be reduced when the movable shaping element is retracted at start-up and only after the start-up has been performed is the protrusion achieved. During start-up of the fiber web forming machine, the forming elements are retracted to the inside of the belt circle and the support behind the elements rests against the inner surface of the belt. During start-up, all lubrication inlets for the sliding surfaces are in use and the web tension can be reduced. In addition, the water removal peak pressure and fabric tension can be controlled. The latter allows control of the water removal profile.

Furthermore, such movable forming elements can be easily replaced when worn or to change the radius of the surface abutting against the belt.

Advantageously, the sliding surface (115) may be arranged adjacent to the movable shaping element (119) and in front of the movable shaping element (119) in the direction of rotation of the belt (41).

Advantageously, the movable shaping element (119) can be moved forwards and backwards along the projection direction (z).

Thus, the movable shaping element can be in at least two positions, i.e. retracted or protruding. Further, in addition to the above advantages, there are also the following advantages.

Advantageously, the forward and backward movement of the movable forming element (119) in the protruding direction (z) can be achieved by means of a piston (1192) housed in a cylinder (1193). The piston (1192) is capable of acting in both directions.

Such an arrangement enables the movable shaping element to be set at any protruding position within the stroke of the piston. Thus, any deflection can be compensated for within a minimum range when arranging adjacent movable shaping elements in the axial direction. In other words, the cross-machine direction bend lines (of the paper or board machine) may be arranged to differ from the intended bend lines by less than 0.25 mm/m.

Advantageously, the movable forming element (119) may be supported at the axle beam (11), the support preferably being a hinge (hinge) (1191) and the forming element of the moving cylinder structure being hinged.

Thus, the rotational force of the belt acting on the movable forming element and the tension from the wire partially wrapped around the liner roll are transferred to the stiff-structured beam without affecting the accuracy in the web forming process. In the case where the movable forming element is supported by a hinge, instead of the linear projection and retraction movement described above, a projection and retraction movement along a curve is carried out. Thereby, in combination with the correspondingly varying radius of the top surface of the movable shaping element abutting the belt, a smooth adjustment of the protrusion height is achieved while maintaining a low friction between the top surface of the movable shaping element and the belt.

The protrusion of the forming elements can affect the belt when the bushing roller radius in the operating position is exceeded. Therefore, good lubrication must be arranged before the forming elements to ensure smooth belt sliding over said elements, tensioning the belt outwards. During start-up, the forming elements may be retracted inside the roller head circle in order to reduce friction.

The projecting/outward travel of the forming element outside the roller head/band circle may be between 10mm and 120mm, advantageously between 20mm and 70 mm. In addition, when the sliding surface can be arranged several millimeters (tens of millimeters) below the head/belt but with the same radius, the belt can be recessed/protruding inwards before the forming element. This helps to reduce the required protrusion/outward travel of the forming elements, which facilitates belt life while reducing belt tension and thereby belt wear.

Therefore, significant variations in the fabric tension wrap (fabric wrap) parameters are possible. On the other hand, excessive forces acting on the belt from the movable shaping element due to friction between the belt and the top surface of the movable shaping element, and bending forces acting on the support of the movable shaping element can be prevented.

Advantageously, in cross section, the surface (1195) of the shaped element (119) abutting against the belt (41) may have a curved convex shape.

Thus, a variation in the curvature of the abutment of the forming element against the top surface of the belt may be applied. Therefore, roll deflection can also be compensated in this way.

Advantageously, the radius of curvature of the curved convex-shaped surface (1195) of the forming element (119) abutting against the belt (41) may become smaller in the direction of rotation of the belt.

Thereby, the web tension profile can be controlled in a smooth manner. Furthermore, the bending of the liner roll can be compensated.

Advantageously, the radius of curvature of the curved shape of the surface (1195) of the forming element (119) abutting against the belt (41) may vary continuously or stepwise (stepwise), wherein the stepwise number of steps may be 3 to 12.

Since the movable forming elements can be easily replaced, different movable forming elements with a dedicated top surface shape can be applied depending on the manufacturing process of the paper or board. The material of the shaped element may be a metal or a polymer (reinforced composite) or a combination thereof. The manufacturing method may be extrusion, machining, additive manufacturing or casting. Low friction coatings or surface hardening may also be used for sliding surfaces and/or shaped elements that are prone to wear.

Advantageously, the sliding surface (115) may cover a sector of 30 ° to 120 ° of the lining roller (1).

Since this range corresponds almost to the net wrap, the friction caused by the net acting on the belt can be reduced considerably. Furthermore, another sliding surface may be added after the movable forming element in the running direction of the belt to support the belt and to reduce the friction in case the movable forming element is retracted, e.g. during start-up of the fiber web forming machine.

Advantageously, the sliding surface (115) may have a radius of curvature in cross section that is the same/constant as the radius of curvature of the roller head (31).

Advantageously, the sliding surface (115) of the sliding element may be surface treated and/or have a depression. Furthermore, the lubricating device (1151) may be arranged in front of the sliding surface (115) and/or across the sliding surface (115) in the direction of rotation of the belt (41). These dimples/recesses/notches extend in one or more discontinuous rows along the length of the axle beam. Between said recesses filled with lubricating oil there is a narrow land area. The length of the recesses and the number of oil inlet openings per recess may be different.

Thus, the friction coefficient is further reduced.

The invention also relates to a paper or board machine comprising two wires (1015, 1009) and a bushing roll (1) as described above in a dewatering or forming section. The wire (1515) on one side of the liner roll (1) abuts the liner roll (1) at the sliding surface (115) transmitting the rotational force to the liner roll's belt (41).

Drawings

In the following, a currently preferred embodiment of the invention will be described on the basis of the accompanying drawings, in which:

figure 1 is a schematic view of a forming section of a paper or board machine using a liner roll according to the invention;

FIG. 2 is a perspective view of a bearing structure supporting a journal of a bushing roller according to the present invention;

FIG. 3 is a perspective view of an axle beam of a bushing roller according to the present invention;

FIG. 4 is a cross-sectional view along the longitudinal axis (length axis) of a liner roll according to the present invention; and

fig. 5 is a cross-sectional view perpendicular to the longitudinal axis of a liner roll according to the present invention.

Detailed Description

Figure 1 shows an example of a schematic structure of a forming section 1000 of a paper or board machine to which a bushing roll 1 according to the invention is applied. The headbox 1001 is used to supply a stock suspension between

wires

1009, 1015, which are guided in a closed loop. The wire loop 1015 is guided by guide roll 1013, forming roll 1005 and liner roll 1. The second web 1009 is guided in a further closed loop by guide roll 1007, forming roll 1005 and lining roll 1. Between the forming roll 1005 and the guide roll 1007a of the guide roll 1007 dedicated to the second wire 1009, both

wires

1015 and 1009 run in parallel to sandwich the web thus formed.

A forming gap (forming gap) having constant radius fabric tension wrap on the forming roll and varying radius fabric tension wrap on the backing roll is formed between the two webs 1015 and 1009 (where the two

webs

1015 and 1009 travel along the circumferential portions of the two rolls) at the circumferential portions of the forming roll 1005 and the backing roll 1, respectively. Since the

webs

1009 and 1015 are slightly elongated in the parts not affected by the rolls, the pressure on the web by the web tension is higher in these fabric stretch wraps than in the parts where the web is unsupported.

The forming gap and fabric tension wrap formed at forming roll 1005 is used to receive the stock suspension from headbox 1001. In order to provide this tension wrap at the forming roll 1005, the second wire is guided towards the forming roll by means of a breast roll 1007b, which is arranged close to the forming roll 1005 in such a way that the diffuser part of the headbox 1 is arranged between the forming roll 1005 and the breast roll 1007 b. Thus, a first dewatering of the web is performed at forming roll 1005.

Another fabric forming wrap is formed at the bushing roller 1. Since this description is primarily directed to the bushing roller 1, the fabric forming wrap formed at the bushing roller 1 will be described hereinafter as a "fabric forming wrap"; meanwhile, if desired, the fabric nip (fabric nip) formed at forming roll 1005 will be described as "constant radius fabric tight wrap" or simply "fabric tight wrap" (at forming roll 1005).

Further, in the forming section, other means for dewatering the web are arranged, such as dewatering elements 1003 or suction boxes 1011. It will be appreciated that the above description of the forming section based on figure 1 is only an example and that there is no intention at all to limit the forming section to the arrangements of wires and elements shown in figure 1 and described above. I.e. beside the described elements, further dewatering elements and suction boxes may be arranged. Alternatively, one or more of the dewatering elements and/or suction boxes shown may be omitted. Furthermore, different types of web forming concepts can be selected that are suitable for all types of forming machines, headbox, layout and web. Also, the function of the liner rolls and their location within the forming machine may vary depending on the specific needs of the particular web being formed.

To form the web, the pulp suspension is fed from the headbox 1001 into the forming gap and into a constant radius fabric tight wrap at the forming roll 1005, where the first dewatering takes place. From there, the web is guided between two

wires

1015 and 1009 to the liner roll 1 and the fabric tension wrap. The web thus passes through the dewatering device 1003, which increases the dryness of the web. In the tight wrapping of the fabric, a second dewatering takes place. With the aid of the bushing roller 1 according to the invention, it is possible to set the parameters of the fabric stretch wrap, such as its length, the pressure it exerts, the travel time of the web through the fabric stretch wrap, etc., as described below. Hereby, effective dewatering is performed before the web is led further via the suction box 1011 to take over and be transferred to the next section, such as the press section of a fiber web forming machine.

The bushing roller 1 according to the invention comprises a shaft beam 11 and a shaft journal 13. As can be seen from fig. 2, the journal 13 is supported in a pedestal (e.g. bearing structure) 21. Furthermore, as can be seen from fig. 4, the lining roller 1 comprises a roller head 31, which supports a belt 41. The belt 41 is tensioned around the axle beam 11 and rotatable around and in relation to the axle beam 11. In particular, the rotation of belt 41 is due to web 1015 coming into direct contact with belt 41 due to web tension during the common path as it passes through liner roll 1.

Returning to fig. 2, the base 21 includes an annular flange 25 mounted on the journal 13 in a manner capable of transmitting torque from the flange 25 to the journal 13.

To provide torque, the flange 25 is connected with a tightening turnbuckle (tightening screw)23 by means of a joint 22. That is, one end of the turnbuckle 23 is attached to the flange 25 by means of the joint 22. The other end of the turnbuckle 23, opposite to the end attached to the joint, is fixed to the base 21. Thus, by turning the turnbuckle 23, the length of the turnbuckle may be lengthened or shortened, thereby causing rotation of the flange 25. The rotation of the flange 25 is transmitted to the journal 13, thereby rotating the journal of the lining roll 1 and the axle beam 11. The flange 25 and the joint 22 form a movement means according to the invention, and the turnbuckle 23 is an example of an actuation means according to the invention.

That is, instead of loosening or tightening the turnbuckle, the actuating means may comprise a screw, gear, worm gear, hydraulic cylinder or other suitable means for providing a longitudinal movement which is then converted into a rotational movement of the flange 25.

As can be seen from fig. 3, the axle beam 11 is made of a hollow polygonal structure with (in this embodiment, eight) rounded corners. Further, the cross section of the axle beam body 111 is symmetrical in different planes, and the width (in the y direction in the drawing) of the axle beam 11 is larger than the height (in the z direction in the drawing). The thickness of the plate forming the axle beam body 111 is between 30mm and 60 mm. This geometry of the axle beam has excellent stiffness in its axial direction (direction of the axis of rotation a) while still being able to form the desired cross-sectional shape.

In the sense of the present invention, rounded corners are to be understood as meaning corners comprising curved, convex, curved portions having a certain radius of curvature.

The head portion 113 of the axle beam 11 has a flange-like shape and is provided with a plurality of mounting holes 1131. The head 113 is surrounded by an axle beam body 111, which is composed of two

bent metal plates

111a, 111 b. The two

metal plates

111a, 111b are welded together at their edges to form a hollow body. The edges are arranged in parallel to the axis of rotation a of the bushing roller 1.

Further, in the axle beam 11, a maintenance opening 117 and other openings are provided to enable access to the inner space of the axle beam 11. Some or all of these openings may be closed with shutters (hatches).

As can be seen in fig. 4, the journal 13 is mounted to the head 113. The roller head 31 is slidably disposed on the journal 13. Thus, the roller head 31 can move in the axial direction of the liner roller 1. To achieve this movement of the roller head 31, hydraulic cylinders (only one of which is shown in fig. 4) 35 are fixed inside the axle beam. The piston rod of each hydraulic cylinder 35 extends through the head 113 of the axle beam 11 and is fixed to the roller head. Therefore, the roller head 31 can be moved in a sliding manner in the direction of the rotation axis a (i.e., leftward and rightward in fig. 4). Thereby, on the one hand, the axial position of the roller head 31 can be determined and, on the other hand, the tension of the band 41 fixed to the roller head 31 and around the axle beam 11 can be adjusted. The plurality of hydraulic cylinders 35 are arranged such that the belt 41 is tensioned with symmetrical tensioning forces.

In order to accurately determine the position of the roller head 31 and/or prevent excessive stretching of the tape 41, indexing means (not shown) is provided to inform a user of the amount of movement of the roller head. In the embodiment, the indexing means shows the distance from the inner side (right side in fig. 4) of the base 21 to the roller head 31.

Furthermore, an opening is provided in the roller head 31 through the journal 13. The openings may be closed in a gastight manner and used for arranging e.g. inlet and outlet pipes for a fluid, such as lubricating oil. Since the opening can be closed in an airtight manner, the pressure inside the belt 41 can be maintained.

As shown in fig. 5, the axle beam has a sliding surface 115. Which extends in the length direction of the axle beam 11 and is curved in the transverse direction of the axle beam 11. In the embodiment the sliding surface is a separate part mounted to the axle beam 11, but the sliding surface may alternatively be formed integrally with the axle beam 11.

Furthermore, a movable shaping element 119 is arranged adjacent to the sliding surface 115 in the axle beam body 111. That is, the forming element is arranged such that the strip 41 passing the sliding surface 115 thereafter passes over the forming element 119. In cross section, the surface 1195 of the shaped element 119 abutting against the belt 41 has a curved convex shape. The radius of curvature of the curved convex shaped surface 1195 becomes smaller in the direction of rotation of the belt 41. Said radius of curvature of the forming element becomes smaller than the radius of the bushing roller. In this regard, the shaping member is movable so that its height protruding from the axle body 111 can be changed. In the axle beam body 111, a pipe system is provided to supply a lubricating fluid to the sliding surface 115.

Since the movable shaping element 119 is configured to protrude from the axle beam 11, it abuts against the belt 41 rotating about the axle beam 11. By varying the projection height of the shaping elements 119, the cross-sectional shape of the loop formed by the strip 41 is varied.

For the purpose of projection or retraction, the movable shaping element 119 is moved forward and backward in its projection direction z. This is achieved by means of a piston 1192 housed in a cylinder 1193. The piston 1192 is able to act in both directions. Thus, the movable shaping element can be made to protrude to a desired height. The protrusion of the shaping elements can affect the belt when the radius of the bushing roller in the operating position is exceeded. Therefore, good lubrication must be arranged before the forming elements to ensure smooth belt sliding on said elements, thereby tensioning the belt outwards. Upon activation, the forming elements may retract inside the roll head circle to reduce friction.

The projecting/outward travel of the forming element beyond the roller head/strip circle (the imaginary shape of the strip section, which is circular unless it is directed in a different way) may be between 10mm and 120mm, advantageously between 20mm and 70 mm. In fig. 5, the band circle is indicated by 41a and drawn with a dashed line. In addition, when the sliding surface is arranged several millimeters (tens of millimeters) below the head/belt but the radii are the same, the belt may be recessed/inwardly projected before the forming element. This helps to reduce the required outward travel, thereby facilitating belt life.

The movable shaping element 119 is supported at the axle beam 11 by means of a hinge 1191. Thus, the position of the movable shaping element 119 may not only be changed in a linear manner, but also be inclined. Advantageously, the movement means of the articulated forming elements can also be inclined/articulated.

In the direction of travel of the belt 41, the sliding surface 115 is arranged before the movable forming element 119. The sliding surface 115 has the same radius of curvature in cross section as the radius of curvature of the bushing roller/roller head 31. Further, the sliding surface is subjected to surface treatment, and may preferably be provided with depressions such as dimples. In addition, in the rotation direction of the belt 41, a lubricating device 1151 is arranged in front of the sliding surface 115. Thus, the coefficient of friction of the sliding surface 115 may be significantly reduced, causing the belt 41 to travel smoothly over the sliding surface 115 before it reaches the movable forming element 119.

It will be appreciated that the cross-sectional shape of the liner roll 1 may vary depending on the requirements of the web being formed, due to the movable forming elements 119. Furthermore, these changes can be performed while the paper or board machine is running. In addition, it is possible not only to vary the cross section of the bushing roller 1, but also to vary the rotational position of the movable forming elements by rotating the journal 13 via the turnbuckle 23 and the flange 25. Thus, a change of the fabric stretch wrap parameters can be achieved in a number of ways, which results in improved dewatering and forming of the web. Reference numeral 116 designates additional sliding elements, one of which is arranged behind the movable shaping element 119.

In addition, fig. 4 and 5

show pipes

110, 112, 114 for supplying and discharging (see arrows in the pipes in fig. 4) lubricant. The supply and discharge is performed via a hole in the journal 13. Furthermore, these tubes are supported in the interior of the axle beam 11. The main drain 120 is used for the back-flowed lubricant, which needs to be cooled and filtered before being re-supplied to the bushing rollers. In addition to the lubricant supply pipes, smaller hydraulic pipes are shown, such as those indicated by 118, 118a, 118 b. These

hydraulic tubes

118, 118a, 118b, described later, are used to actuate the piston 1192. The connections to the hydraulic actuator, the lubricant collector device and the lubricant supply/injection pipe are performed by means of steel reinforced hoses to allow thermal movements and bending.

Although the present invention has been described based on the presently preferred embodiments of the invention, the scope of the present invention is not limited to the above description and drawings, but is defined by the claims.

Accordingly, variations may be made to the embodiments. For example, the described cross-sectional shape need not be provided for the entire axle beam body, but only a portion of the axle beam body may have a polygonal cross-section. One or more of the other portions may have a different cross-section.

The polygonal cross-section may have six to twelve corners or corresponding angles. Although it is preferred to round the corners, such a chamfer is not specifically necessary, for example in the case of a metal plate that is not bent but a plurality of metal strips welded together to form the axle beam body.

Additionally, at least a portion of the axle beam body may have a circular cross-section.

Instead of continuously changing, the radius of curvature of the curved shape of the surface of the forming element abutting against the belt may be changed stepwise. The number of stepwise steps may be 3 to 12.

Although no range of wrap is mentioned above, the sliding surface may cover a sector of 30 ° to 120 ° of the liner roll, so that a wire with a common wrap on the liner roll may drive the belt with the help of the supporting sliding surface.

Although in the embodiments the lubricating means is arranged before the sliding surface in the direction of rotation of the belt, the lubricating means may alternatively or additionally be provided by the sliding surface. The arrangement of the lubricating device depends on the components before the sliding surface is formed.

Although a polygonal configuration is depicted in the cross-section of the axle beam, in some cases other more complex dimensional shapes may be used, such as the cross-section of a T-beam, Y-beam, or X-beam.

Claims

1. A bushing roller (1) comprising:

an axle beam (11) having a journal (13), the journal (13) being supported in a bearing structure (21);

a roller head (31) configured to support a belt (41) tensioned around the axle beam (11) in the form of a belt loop and rotatable around the axle beam (11);

the belt (41) being rotatable about and relative to the axle beam (11); and

a movable shaping element (119) configured to protrude from the axle beam (11) so as to abut against the belt (41) to change the cross-sectional shape of the belt loop.

2. Bushing roller (1) according to claim 1, wherein

A sliding surface (115) is arranged adjacent to the movable shaping element (119) and in front of it in the direction of rotation of the belt (41).

3. Bushing roller (1) according to claim 1 or 2, wherein

The movable shaping element (119) is movable forwards and backwards in a projection direction (z).

4. Bushing roller (1) according to claim 3, wherein

The forward and backward movement of the movable forming element (119) in the protruding direction (z) is achieved by means of a piston (1192) housed in a cylinder (1193), the piston (1192) being able to act in both directions.

5. The bushing roller (1) of any one of the preceding claims, wherein

The movable shaping element (119) is supported at the axle beam (11), the support preferably being a hinge (1191).

6. The bushing roller (1) of any one of the preceding claims, wherein

The stroke of the forming element (119) projecting from the circumference of the roller head or the circumference of the circle (41a) is in the range of 10mm-120mm, preferably 20mm-70mm, when viewing the cross section of the strip (41).

7. The bushing roller (1) of any one of the preceding claims, wherein

In cross section, the surface (1195) of the forming element (119) abutting against the belt (41) has a curved convex shape.

8. The bushing roller (1) of claim 7, wherein the radius of curvature of the curved convexly shaped surface (1195) of the forming element (119) abutting against the belt (41) becomes smaller in the direction of rotation of the belt.

9. The bushing roller (1) of any of claims 7 and 8, wherein the radius of curvature of the curved shape of the forming element (119) abutting against the surface (1195) of the belt (41) changes continuously or stepwise, wherein the stepwise number of steps can be 3 to 12.

10. The bushing roller (1) of any one of claims 2 to 9, wherein

The sliding surface (115) covers a sector of 30 ° to 120 ° of the lining roller (1).

11. The bushing roller (1) of any one of claims 2 to 10, wherein

The sliding surface (115) has the same radius of curvature in cross section as the radius of curvature of the roller head (31).

12. The bushing roller (1) of any one of claims 2 to 11, wherein

The sliding surface (115) of the sliding element is surface treated and/or is provided with recesses.

13. The bushing roller (1) of any one of claims 2 to 12, wherein

In the direction of rotation of the belt (41), a lubricating device (1151) is arranged in front of the sliding surface (115) and/or passes through the sliding surface (115).

14. A paper or board machine comprising, in a dewatering section:

two nets (1015, 1009), and

the bushing roller (1) of any one of claims 2 to 13,

wherein the wire (1515) on one side of the liner roll (1) abuts the liner roll (1) at the sliding surface (115) transferring rotational forces to the liner roll's belt (41).