EP4671438A1

EP4671438A1 - COAT ROLLER FOR A FORMING SECTION OF A FIBERGLASS MACHINE

Info

Publication number: EP4671438A1
Application number: EP24183962.0A
Authority: EP
Inventors: Kari Holopainen; Timo HÄMÄLÄINEN; Seppo Kupiainen; Sami Lamminparras; Antti RÄKKÖLÄINEN; Jorma Snellman; Janne Virtanen
Original assignee: Valmet Technologies Oy
Current assignee: Valmet Technologies Oy
Priority date: 2024-06-24
Filing date: 2024-06-24
Publication date: 2025-12-31
Also published as: CN121205026A

Abstract

The invention relates to a sleeve roll for a forming section of a fiber web machine. The sleeve roll (21) has an axle beam (28) supporting a plurality of actuator systems (52) arranged side by side and attached to a convex forming element (22). Each actuator system (52) has an actuator (53), which in one or more actuator system (52) has an adjustable reach.

Description

The invention relates to a sleeve roll for a forming section of a fiber web machine, which sleeve roll has an axle beam supporting a plurality of actuator systems arranged side by side and attached to a convex forming element.
EP-patent application number 3913136 discloses a forming section of a fiber web machine. There is a sleeve roll having a belt loop arranged to rotate around an axle beam. Inside the sleeve roll there is a convex forming element forming a dewatering zone. The convex forming element is supported with several actuator systems fitted to the axle beam. The actuator systems move the convex forming element pushes the wire tension together with radius change and urge the belt loop. The forming element is convex having a curvilinearly reducing surface radius in the rotation direction of the urged belt loop. The wire tension together with radius change pushes water out the fiber web formed by the fiber web machine such as paper, board, pulp, or tissue machines.
Although the sleeve roll has an improved water removal efficiency and it enables controlling of the water removal peak pressure and of the fabric tension, the known sleeve roll has some challenges. It is hard to manufacture a small-sized sleeve roll which conforms to the variable lengths and positions of the belt loop surface in the length wise of the forming element. If the conforming is handled by the specially shaped forming element, the machining of the convex forming element is hard and time consuming. At the same time, the machined convex forming element is suitable for only limited sizes of the sleeve roll. Alternatively, the convex forming element may be bent in some extend. However, bending causes high stresses to the actuator systems and requires a very rigid axle beam. This further increases the size of the sleeve roll. In addition, it is laborious to maintain or change the actuator system. Also the assembling of the convex forming element like the whole sleeve roll is time consuming.
It is an object of the invention to provide for a forming section of a fiber web machine a sleeve roll, which is simpler but versatile than before and yet easier to manufacture and maintain. The characteristic features of the sleeve roll according to the invention are stated in the accompanying claims. The actuator system is more accurate than before from the supporting and joining structure side while the actuators have a very accurate adjusting means. Together with enhanced forming element structure the sleeve roll bending can be compensated precisely with ease. The sleeve roll with the convex forming element is very advantageous in the forming section where it can affect even to the formation of the fiber web. In the initial part of the forming section there is a lot of free water present, and the dry content of the fiber web is between 2 - 17 % which is very suitable for the sleeve roll. The sleeve roll is very efficient in dewatering in the forming section which gives big energy savings compared to traditional vacuum devices or vacuum rolls or press nips where rolls are loaded against each other. The sleeve roll is also gentler in water removal so that the fiber web does not get compacted like with said prior art.
The invention is described below in detail by referring to the enclosed drawings, which illustrate some of the embodiments of the invention, in which

Figure 1: shows a schematic side view of a forming section equipped with a sleeve roll according to the invention,
Figure 2: shows a cross section in cross direction of the sleeve roll according to the invention,
Figure 3: shows a partial cross section in machine direction of the sleeve roll according to the invention,
Figure 4a: shows a cross section of the actuator system according to the invention seen from the side,
Figure 4b: shows a cross section of the actuator system according to the invention seen in machine direction,
Figure 4c: shows a cross section of the forming element.

In the shown embodiment of Figure 1, the forming section includes a first wire loop 10 and a second wire loop 11. The first wire loop 10 circles over a forming roll 12 while the second wire loop 11 circles over a breast roll 13. The travel direction of the first wire loop 10 is designated with an arrow 14 and the travel direction of the second wire loop 11 is designated with an arrow 15. The first wire loop 10 and the second wire loop 11 form a converging gap 16 such that both wire loops 10 and 11 converge on the area of the forming roll 12. The forming section also includes a headbox 17 for feeding pulp suspension to the gap 16 between the wire loops 10 and 11. After the forming roll 12, there are three suction boxes 18, 19, 20 for water removal. Next there is the sleeve roll 21 according to the invention. Both wire loops 10 and 11 travel over the sleeve roll 21 equipped with a convex forming element 22 for water removal. Preferably the convex forming element is a curvilinear forming element.
The sleeve roll 21 is followed by a twin-wire section on which water is removed from the fiber web 23 travelling between the wire loops 10 and 11 with a suction box pair 24 being below the first wire loop 10. At the end of this twin-wire section, the travel direction of the second wire loop 11 is diverted with a second guide roll 25 and led to the return cycle. At the point of the second guide roll 25, the second wire loop 11 is separated from the first wire loop 10, in connection with which the fiber web 23 is attached with another suction box pair 26 to the first wire loop 10 and conveyed on the upper surface of the first wire loop 10 over a third guide roll 27 and then picked up to the following press section.
The sleeve roll is especially for a wire section of a fiber web machine. The sleeve roll 21 has an axle beam 28 supporting a plurality of actuator systems 52 arranged side by side and attached to a convex forming element 22. Figure 2 shows the sleeve roll 21 seen from side and Figure 3 shows the sleeve roll 21 viewed in machine direction. Before the convex forming element 22 in the rotating direction of the belt loop 30 there is a lubricated sliding surface 31 for the belt loop and fabric support and lubrication of the forming element 22. Then both wire loops 10 and 11 have good support. With support on sliding surface for the fabric tension wrap, the wire loops can drive the belt loop. Simultaneously, the friction between the sliding surface and the belt loop remains low. And more, the convex forming element is lubricated at the same time when the lubricant travels with the belt loop. Here the sliding surface 31 is a metal or metal-plate structure supported on the axle beam 28. In principle, the sliding surface can be part of the axle beam.
Here the sliding surface 31 has a curvature R corresponding to the radius of the roll head 29 shown in Figure 3. Then the belt loop together with the wire loops run smoothly with low friction, but good support. After the sliding surface, the forming element urges the belt loop outwardly causing fabrics and the web to follow the smaller radius of the convex forming element which induces raising pressure which effectively removes water out of the fiber web. In Figure 2 the belt loop 30 is shown in its un-urged cylindrical shape with dashed line and over the urged convex forming element with continuous line.
The sliding surface 31 defines a zone 32 of 30 - 120 degrees. The sliding surface gives support to the wires and fiber web sandwiched therebetween initiating the water removal just before the forming element. In Figure 2 the zone 32 is about 80 degrees. Even this large zone is possible by the lubrication which keeps friction low. Here, before the sliding surface 31 there is a shower pipe 33 for lubrication. The lubricant is fed via the center bore 34 of the stationary axle stub and then led out also via center bore 34.
The sleeve roll shown in Figure 3 is for a wire section of a fiber web machine, as described above. The sleeve roll 21 includes an axle beam 28 and two preferably circular roll heads 29 having axle stubs 35 supported on the axle beam 28 and arranged to rotate. Each roll head is preferably circular having a fixed radius. In addition, the sleeve roll 21 includes the belt loop 30 arranged around the axle beam 28 and tensioned between the roll heads 29. The circular roll heads 29 form the belt loop 30 in cylindrical shape especially when tensioned and rotating. Then the belt loop 30 can rotate around the axle beam 28. In addition, the convex forming element 22 is arranged between the axle beam 28 and the belt loop 30. The convex forming element 22 is in contact with the belt loop 30 to form rising pressure for water removal. The convex forming element urges the belt loop 30 locally outwards from its round form to follow the smaller radius forming element. The curved shape of the convex forming element changes continuously or stepwise shorter in radius.
The sliding surface 31 is equipped one or more fluid pocket 36. The size of the pockets can vary from a counter sunk of single hole to long channel with several feed holes extending to axial direction of the sleeve roll. Fluid pockets are arranged in rows of several pockets and the rows of the lubricant pockets can be controlled and used individually. For example, in start-up and/or running modes different number of rows takes part to lubricating. Lubricant is fed through the axle beam to these fluid pockets. Then, especially during the start-up, lubricant spreads from the fluid pockets between the sliding surface and the belt loop, so that there is continuous oil film over all surface area. Then, the belt loop is unadhered and the belt loop can start rotating with low friction like a hydrostatic lubrication.
Running lubrication can be done also with combination of fluid pockets and lubrication pipes bringing more lubrication and cooling. There is a fluid collector 37 before the sliding surface 31 or the forming element 22. The location of the fluid collector depends how the sleeve roll is installed. In Fig. 2 and Fig. 3, the fluid collector 37 is before the forming element 22. Then the excess lubricant is collected before the forming element 22. The fluid collector should be covered by lubricant to achieve powerful removal of lubricant. Excess air entering the outlet pipe weakens the efficiency of the removal.
In the shown embodiment, the fluid collector 37 has at least one edge 38 arranged adjacent to sliding surface and forming element and is located between said elements. In other words, the fluid collector is integrated next to sliding surface and part of the fluid collector can be attached to the forming element. This makes the structure efficient in every driving mode. It may also be at least partly tiltable. Then, the fluid collector conforms to the movement of the forming element. This avoid splashing of the lubricant when the fluid collector is always in right position to the forming element.
As shown in Fig. 2, the fluid collector 37 has a return connection 39 to a center bore 34 arranged to the axle beam 28 for removing lubricant from the sleeve roll 21. Then the lubricant is led out of the sleeve roll to be filtered and cooled. In this way, the amount of lubricant inside the sleeve roll is minimized which reduces the weight of the sleeve roll. Also, lubricant is cooled when again feed with the shower pipe and fluid pockets which both ensure longer lifetime for the belt made from reinforced polymer structure vulnerable to excess heat and wear.
The belt loop 30 is tensioned by moving at least of one of the roll head 29 axially. Here, the roll head 29 is preferably equipped with a tension device 41 having hydraulic conducts 42 inside the axle 28 and a center bore 34 arranged to the axle 28. The structure is simple, and the tension of the belt loop can be adjusted precisely and apart from other adjustments of the sleeve roll. Here, the tension device 41 can be a double-action cylinder connected to the roll head 29. The roll head is preferably in two parts. The first part is an inner ring 43, which is non-rotating, but can slide axially. The second part is an outer ring 44 which is rotary by the bearing 46. Thus, the belt loop can be adjustable tensioned even during the rotation. For example, at the start-up when lubricant is cold, the tension may be low. Then, after production is started and the convex forming element urged out, the tension may be tuned to optimize runability of the sleeve roll and the whole forming section.
The forming element 22 is movable in and out, but also can be tiltable and/or movable in relation to the axle beam 28. The forming element can be pivoted at its front end, and it is urged against the belt loop 30 by plurality of actuator systems, preferably by hydraulic devices 45. Again, the hydraulic pressure is led via the center bore as described above. There are significant forces especially in the straightness requirement of the forming element which requires several parallel actuator systems. If the forming element is not straight in cross machine direction during use the wires can get speed difference that affect wires and web so that wires can wear or even fold. In the center bore 34 there are first rigid pipes 46 and then steel braided hoses 47 leading pressurized oil in and out from double-acting hydraulic devices 45. The hoses flex if some movements or deformations occurs. Steel braided hoses are advantageous also for other lubricant feed and removal arrangements inside the sleeve roll.
After the pipe 48, next is such as a conduit 37 for feeding lubricant to the fluid pockets 36. The third is a rigid pipe 46 is for hydraulic devices 45 moving the forming element 22. The fourth is the hydraulic conducts 42 for tension device 41. Then there is a joint 50 for feeding pressured air inside the sleeve roll 21 in order to aid removal of lubricant. When the fluid collector is filled with lubricant, lubricant can be pumped out of the sleeve roll. Advantageously, the interior of the sleeve roll 21 is on overpressure. Pressure aids the lubricant removal and keeps the sleeve roll circular. For closing the sleeve roll there is a seal 49 at the end of the axle beam 28.
The axle beam 28 includes two axle stubs 53. The axle beam 28 is advantageously partially polygonal having arc shaped sliding surface in cross section. Such a structure ensure maximum cross section with room for forming element. Thus, the axle beam is rigid and can be positioned in any angle. At least partly, advantageously wholly, there are at least at least three rounded convex corners, and the sides of the axle beam can have different length to fit equipment inside the sleeve roll better.
The sleeve roll has a good possibility of changing the dewatering process by position of the forming element. Here, the end of the axle beam 28 has also a rocker bearing 50 and there is rotating means 51 between the axle 28 and a bearing bracket 56 belonging to the rocker bearing 50. Thus, the alignment of the sleeve roll can be fine adjusted. Then the wearing of the belt loop and wire loops are minimized, and the water removal is maximized. This turning during start-up is illustrated in Figure 1.
The forming element is preferably convex, and it protrudes out of the circular belt loop. By urging the forming element tensions the belt loop in both machine direction and cross machine direction while no other roll is involved. The protrusion of the forming element is on its maximum advantageously smaller than 120 mm, advantageously 50 - 90 mm. The sliding surface can be arranged also inwards from the belt radius to form an indent support for the belt loop which can reduce need for outward protrusion or enables the same effect to the fiber web with less protrusion. Said arrangement reduces the local elongation of the belt and can help to increase the belt lifetime. Preferably the indent of the sliding surface is less than 40 mm. Retraction of the forming element inside the circumference of the belt loop reduces friction in the start-up of the forming section. Convexity of the forming element gets bigger in running direction which means that the radius is getting shorter. The change of the radius can be either continuous or stepwise with 3 - 12 steps, advantageously 5 - 9 steps of radius. These changes or steps help to adjust the pressure curve affecting the fiber web. In the cross-machine direction, the edge areas in both end of the forming element have radius that is equal or bigger than the smallest radius in machine direction. Axial distance between the straight part of the forming element and roll head belt locking is 150 - 800 mm.
There is fabric tension wrap over the sleeve roll before forming element together with the lubricated sliding surface prior to the forming element. With the fluid pockets and/or fluid showers in connection the sliding surface also the forming element is lubricated. The sliding surface and the forming element create together a friction surface on the area of the fabric tension wrap. The wrap against the sleeve roll is advantageously 30 - 120 degrees. The sliding surface has about the same radius than the roll head which keeps the belt loop tensioned and on its circular path. The sliding surface makes the axle beam more rigid against bending when properly joined. Also, the sliding surface can be lubricated against friction and there are lubrication showers prior to sliding surface and and/or through said surface. The pipe of the lubrication shower before sliding surface forms a kind of lubrication pocket by closing the oils route against the belt rotation. The fabric tension against the belt loop on the sliding surface during wrap over it arranges the driving power to the sleeve roll. Lubricant is fluid, preferably oil. Also compressed air or mixture of air and oil or even water can be used, especially with the fluid pockets of the sliding surface.
The axle beam can be made of hollow polygonal and/or round beam structure giving support to the forming element and other devices and have room inside the belt loop for said equipment. Said axle beam is preferably made of polygonal, say 6 - 12 rounded corners, beam structure with axle stubs attached to it. The polygonal form comes preferably from bended metal plates which are welded together from at least two pieces. Alternatively a cast axle beam may be used. The polygonal axle beam is rigid to large angle of tension forces from both belt loop together with the forming element protrusion and fabric wrap. Surprisingly, both high I-shaped and simple square beams meant to press nips were poor for sleeve roll solutions with varying angle of forces. Metal plate thickness is advantageously 30 - 60 mm. Polygonal structure is advantageously symmetric in different planes a polygonal and curved closed beam close to belt loop wherein curved part is contouring the belt run supporting it. The axle beam is designed for loading requirements and for room to fit equipment. For example, the axle beam can be a bit higher and larger in the wire tension direction of the wrap over the sliding surface. Also the forming element is narrower and has room for accommodate. Moreover, there is room for the convex forming element and belt supports outside the axle beam and it also fit the convex forming element moving equipment and fluid connections inside the axle beam. The axle beam can have opening and hatches for service of the devices inside the axle beam.
According to the invention, each actuator system 52 has an actuator 53, which can be a double-acting hydraulic cylinder, for example. In addition, in one or more actuator system 52, the actuator has an adjustable reach. In other words, the distance which the actuator moves the convex forming element can be adjusted. In this way, the shape of the convex forming element can be changed for deflection compensation. At the same time, the convex forming element may have a uniform cross section essentially over the working width W. This make the manufacturing much easier. Also one and same convex forming element may be used in different positions and sleeve rolls by simply adjusting each actuator. In practice, the longest reaches are at the middle actuators while shortest are at the outermost actuators when the forming element is at the top position. The actuator elements can be easily adjusted to adapt any position of the sleeve roll. In practice, the length of the adjustable reach of the actuator 53 may be 0,5 - 10 mm, more typically 2 - 6 mm.
The convex forming element 22 is fixed in the longitudinal direction in one of the middle actuator systems 52 while the other actuator systems 52 are floatingly arranged. In practice, at one spot, the convex forming element is attached to the actuator system. This fixing keeps the convex forming element in place in the axial direction of the sleeve roll. However, the convex forming element can be lengthened and shorten due the thermal expansion.
In the shown embodiments, the actuator 53 is a cylinder 54 having an outer threading 55 while the actuator system 52 has a corresponding inner threading 56. In this situation, the reach of the actuator is adjusted by rotating the actuator with respect to the actuator system. In practice, the actuator is driven to its full stroke and back. More precisely, all actuators are stroked simultaneously. In other words, there is one common in- or out-command for all actuators. Also, the reaches of the actuators are designed and dimensioned before the installation. So the reach of the actuator stays unchanged during the operation of the sleeve roll. However, if needed, the reach may be fine-tuned during the maintenance.
Instead of or in addition to the installation mentioned above, the actuator 53 is a cylinder 54 having a length-adjustable piston rod 57. By this, especially the fine tuning is easy, without moving the cylinder itself. One fine-tuning arrangement 58 is shown in Figure 4b.
According to the invention, there is an even number of actuator systems 52. In practice, the sleeve roll has typically from four to eighteen actuator systems. In this way there is an unobstructed access to two actuators from each hatch 59, which is positioned between the actuators systems. One hatch 59 is shown in Figure 3.
The convex forming element 22 has an attachment surface 60, which is advantageously planar. This also simplifies the manufacturing of the convex forming element, when the blank of the forming element can be locked to the machining machine rigidly, but easily. According to the invention, the attachment surface 60 has a groove 61 extending in the longitudinal direction of the convex forming element 22. In the shown embodiment, the convex forming element has a single groove in the middle and covering most of the thickness of the convex forming element. Even one groove makes the convex forming element more flexible, even 300 less stress than without any groove. Thus smaller actuator systems are needed and thereby smaller axle beam. In practice, the groove 61 is continuous and extends between the outermost actuators 53, as shown in Figure 3. The groove is machined after the convex forming element is machined being rigid without any groove or other local loose spots. There may be more than one groove. The groove is narrower that its depth. Narrow and deep groove is easy machine by a round blade, for example. Also the bending stiffness of the forming element remains as high as possible.
Figures 4a and 4b show the actuator system 52 according to the present invention in more detail and in cross section. Advantageously, the actuator system 52 has a saddle 62 fixed to the axle beam 28 and a nut 63 articulated to the saddle 62 wherein the actuator 53 is fixed inside the nut 63. Here, the are two pivots 64 on the opposite sides of the nut 63. Thus the cylinder 54 can go through the nut 63 and swing in relation to the nut 63 when the convex forming element 22 goes in and out.
Here, there is a swing arm 65 articulated to the saddle 62 and having a rear support 66 for the convex forming element 22. The saddle 62 is fixed to the axle beam 28 and the swing arm 65 is attached to the saddle 62 by a spindle 67. The structure is simple and robust without any play. The structure is also low. The actuator 53 is attached to the swing arm 65 with a pin 68. Thus the movement of the forming element follows a regular arc, and the actuator can swing accordingly.
In addition to the attachment surface 60, the convex forming element 22 has a continuous slot 69 both at the income edge and the trailing edge. The majority of the structures of the convex forming element are continuous over the length. This structure is easy to manufacture, and the forming element bends logically and uniformly. The slot behind equals to the rear support 66 of the swing arm 65. The rear support responds to loads and keeps the forming element in place. The fixing is secured with a locking piece 70 fixed to the swing arm 65 with two bolts 71. Thus it is easy to install the forming element and thermal expansion is enabled.
As shown in Figure 4a, the nut 63 has a slot 72 covering a part of the circumference of the nut 63, and there is a locking bolt 73 urging the nut 63 in the area of the slot 72. When the cylinder 54 is rotated in right altitude, the locking bolt is tightened and thereby urging the nut 63 and its inner threading 56. This secures the cylinder 54 in place.
Basically the only component needing maintenance or replacing is the actuator. Due the structure explained above, it is easy to change the actuator. The hydraulic hoses 47 are dis-joined, the locking bolt 73 is released and the pin 68 is removed. Then the actuator is rotated and pulled out without dismantling any other element or structure. The replacement of the new actuator is done in the reserve order. The replacement takes few minutes when in the known concept it will take several hours.
Advantageously, the swing arm 65 is a single piece. One piece is easy to machine, and it bears heavy loads. In addition, the convex forming element is kept steadily in place and in right position. Also, it is easy to install the convex forming element. It can be easily laid down on the top of the swing arm and locked with the locking pieces.
Also, the saddle 62 is a single piece. Thus the internal interfaces are minimized. The saddle may be casted or 3D-printed as well the swing arm and the nut. In this way there are a minimum number of pieces attached to each other with simple and precise and playless pivots. This structure is easy to manufacture and mantle and finally stable to use and quick to maintain.
The structure according to the invention minimizes the interfaces between the forming element and the actuator systems and optimizes their manufacturing. Simultaneously, high straightness and good surface quality can be economically achieved to the forming element ensuring long lifetime for the belt loop. During the machining, the forming element is stiff, and it has simple forms. This enables easy fastening and large machining values which reduce time and costs. Each actuator system is individually adjusted to its own position according to needs of the runability of the sleeve roll. And more, maybe the only wearing or aging part of the actuator system, the cylinder itself, can be replaced without the need to remove the forming element from the sleeve roll. In addition, the bombing of the convex forming element is easy to implement and even adjustable.

Claims

Sleeve roll for a forming section of a fiber web machine, which sleeve roll (21) has an axle beam (28) supporting a plurality of actuator systems (52) arranged side by side and attached to a convex forming element (22), characterized in that each actuator system (52) has an actuator (53), which in one or more actuator system (52) has an adjustable reach.
Sleeve roll according to claim 1, characterized in that the convex forming element (22) is fixed in the longitudinal direction in one of the middle actuator systems (52) while the other actuator systems (52) are floatingly arranged.
Sleeve roll according to claim 1 or 2, characterized in that the actuator (53) is a cylinder (54) having an outer threading (55) while the actuator system (52) has a corresponding inner threading (56).
Sleeve roll according to claim 1 or 2, characterized in that the actuator (53) is a cylinder (54) having a length-adjustable piston rod (57).
Sleeve roll according to any of claim 1 - 4, characterized in that there is an even number of actuator systems (52) .
Sleeve roll according to any of claim 1 - 5, characterized in that the convex forming element (22) has an attachment surface (60) having a groove (61) extending in the longitudinal direction of the convex forming element (22).
Sleeve roll according to claim 6, characterized in that the groove (61) is continuous and extends between the outermost actuators (53).
Sleeve roll according to any of claim 1 - 7, characterized in that the convex forming element (22) has a uniform cross section essentially over the working width (W).
Sleeve roll according to any of claim 1 - 8, characterized in that the actuator system (52) has a saddle (62) fixed to the axle beam (28) and a nut (63) articulated to the saddle (62) wherein the actuator (53) is fixed inside the nut (63) .
Sleeve roll according to claim 9, characterized in that the nut (63) has a slot (72) covering a part of the circumference of the nut (63), and there is a locking bolt (73) urging the nut (63) in the area of the slot (72).
Sleeve roll according to claim 9 or 10, characterized in that there is a swing arm (65) articulated to the saddle (62) and having a rear support (66) for the convex forming element (22).
Sleeve roll according to 11, characterized in that the swing arm (65) is a single piece.
Sleeve roll according to any of claim 9 - 12, characterized in that the saddle (62) is a single piece.
Sleeve roll according to any of claim 1 - 13, characterized in that the length of the adjustable reach of the actuator (53) is 0,5 - 10 mm.
Sleeve roll according to any of claim 6 - 14, characterized in that the groove (61) is narrower that its depth.