Installation and method for producing kraft paper, said installation having a bypass assembly
The integration of a bypass assembly in paper production systems allows for maintenance of the compacting apparatus without halting production, ensuring continuous operation and diverse paper quality.
Patent Information
- Authority / Receiving Office
- AU · AU
- Patent Type
- Applications
- Current Assignee / Owner
- MONDI AG
- Filing Date
- 2025-01-28
- Publication Date
- 2026-07-23
AI Technical Summary
Existing paper production systems face challenges in efficiently compacting fibrous webs while allowing for maintenance without disrupting the production process, particularly when the compacting apparatus requires servicing.
A bypass assembly is integrated into the system, enabling the fibrous web to be diverted around the compacting apparatus during maintenance, utilizing an adjustable diverter and rope guides to selectively route the web through either the compacting apparatus or a bypass path, maintaining production continuity.
Ensures continuous paper production even during maintenance of the compacting apparatus, producing paper with different properties that can still be utilized, thereby enhancing operational flexibility and efficiency.
Smart Images
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Abstract
Description
The compacting apparatus 21 comprises a belt 26. The belt 26 is a continuous band that is guided around multiple deflection rollers 59 or deflection rolls. In particular, the compacting apparatus 21 preferably comprises a belt drive roll 31 with a belt drive 27. The belt drive 27 drives the belt drive roll 31, the belt drive roll 31 preferably being in direct operative contact with the belt 26 so as to drive it in a continuous loop. The compacting apparatus 21 comprises a nip bar 33. The nip bar 33 is configured to be displaceable and can press the belt 26 towards and against a counter roll 28, as done in the present position. In the present embodiment, the counter roll 28 has a counter roll drive 29. Preferably, the counter roll drive 29 and belt drive 27 are drives that are independently controllable and are preferably rotary drives. A compaction nip 30 is formed between belt 26 and counter roll 28. The compaction nip 30 is bounded by the counter roll 28 on one side and on the other side by the belt 26. The position of the compacting apparatus 21 shown substantially corresponds to the compacting mode in which the fibrous web is compacted. In the compacting mode, the fibrous web passes through the compaction nip 30 at production speed, and is conveyed therein between the moving belt 26 and the counter roll 28, and is thereby compacted in the machine flow direction 1. In the compacting mode, the belt 26 is driven by the belt drive 27. In the compacting mode, the counter roll 28 is driven by the counter roll drive 29, whereby the belt 26 and the counter roll 28 are each driven by a respective drive in the compacting mode. In the compacting mode, the circulation speed of the belt 26 and the circulation speed of the counter roll 28 preferably exceed 400 m / min, in particular exceed 600 m / min, and substantially equal the production speed. The thickness of belt 26 is reduced in the region of the compaction nip 30, as the nip bar 33 presses the belt 26 towards the counter roll 28 in that region, thereby pressing the belt from the nip bar 33 towards the counter roll 28. Downstream of the nip bar 33 in the fibrous web travel direction 23, the thickness of the elastically deformed belt 26 returns to its original thickness. A transverse contraction effect causes the belt 26 to contract by a certain amount along its travelling direction, leading to local reduction in the speed of belt 26. As the fibrous web lies on the belt 26 in this area, the fibrous web is compacted by this effect. The web is compacted in the machine flow direction 1. This procedure can be set, preferably by adjusting the wrap roll 34, so that the contact time of the fibrous web between the belt 26 and the counter roll 28 is adjustable by means of a wrap angle of about 15°-90°, preferably between 20°-45°. By shifting the nip bar 33, the pressure or force acting on the rubber belt 26 upstream of the nip bar 33 towards the counter roll 28 can be reduced or completely eliminated. By relieving the pressure caused by the nip bar 33, the compacting apparatus 21 can be switched into a free-running mode. In both operating modes - that is, in compacting mode and in free-running mode - the two drives may preferably drive the belt 26 and counter roll 28. Preferably, the belt and counter roll are driven at a speed that is substantially equal to the production speed. In the present embodiment, the compacting apparatus 21 comprises a tension roll 32. Said tension roll 32 is used to maintain the tension of the belt 26. Tension roller 32 is preferably designed to be displaceable and maintains the tension of the belt 26, when, for example, the belt extends due to wear. Further, tensioning roll 32 may optionally also keep the belt 26 tensioned when the nip bar 33 is retracted. In the present embodiment, the compacting apparatus 21 comprises a wrap roll 34. Preferably, the wrap roll 34 is arranged such that the belt 26 runs along the outer contour of the counter roll 28, at least in one portion. The position of the wrap roll 34 thus determines the wrap angle of the belt 26 around the counter roll 28. The larger the wrap angle, the longer the contact length of the belt 26, and thus also of the fibrous web, on the counter roll 28. In compacting mode, the belt 26 is therefore guided around the counter roll 28 by the wrap roll 34 and the nip bar 33 over a wrap angle. In the present embodiment, the wrap roll 34 is configured to be displaceable, thereby enabling adjustment and changing of the wrap angle. The system comprises a bypass assembly 46 in the area of the compacting apparatus 21 for conveying the fibrous web along a bypass path 47, bypassing the compacting apparatus 21. The bypass assembly 46 is preferably provided exclusively in the area of the compacting apparatus 21 and is designed for conveying the fibrous web by bypassing the compacting apparatus 21 but not by bypassing other system components. In particular, the compacting apparatus 21 is arranged in the machine flow direction 1 between a system component upstream of the compacting apparatus 21 and a system component downstream of the compacting apparatus 21. The bypass path 47 of the bypass assembly 46 extends from the exit of the upstream system component to the entrance of the downstream system component. The dryer section 6 comprises a pre-dryer section 19 and an after-dryer section 20 arranged downstream of the pre-dryer section 19 in the machine flow direction 1. The compacting apparatus 21 is preferably arranged between the pre-dryer section 19 and the after-dryer section 20 in the machine flow direction 1. The bypass assembly 46 may convey the fibrous web from the pre-dryer section 19 to the after-dryer section 20, bypassing the compacting apparatus 21. The bypass assembly 46 comprises an adjustable diverter 48 for selectively conveying the fibrous web or a strip of the fibrous web through the compacting apparatus 21 or through the bypass path 47. For example, the diverter 48 is configured as an adjustable suction belt or vacuum belt. Further, a rope guide 49 is provided for selectively guiding a strip of the fibrous web through the bypass assembly 46 or through the compacting apparatus 21. Fig. 2 shows a schematic side view of components of the system and in particular also of the bypass assembly 46 and the rope guide 49. The bypass assembly 46 allows the fibrous web produced on the system to be selectively guided through the compacting apparatus 21 or through the bypass assembly 46. In the bypass assembly 46, the fibrous web is guided along a bypass path 47 past the compacting apparatus 21. Preferably, the fibrous web runs through all parts of the system with the exception of the compacting apparatus 21. If, for example, the compacting apparatus 21 requires maintenance, the fibrous web cannot be conveyed through the compacting apparatus 21 for safety reasons, but usually also for technical reasons. In this case, the fibrous web is guided past the compacting apparatus 21 by the bypass assembly 46. While the compacting apparatus 21 is being maintained, the present structure can be used to produce paper that has not been longitudinally compressed by the compacting apparatus 21. This paper generally has different properties than a paper compacted in the compacting apparatus 21. However, the paper produced without the compacting apparatus 21 can still be used as a product. If the fibrous web is to be fed through the bypass assembly 46 instead of through the compacting apparatus 21, the process may be as follows: Preferably, the fibrous web is cut off by a web cutting device 45 (see Fig. 1b). Subsequently, not the entire fibrous web is guided over its entire width, but only a narrow strip of the fibrous web is guided towards the compacting apparatus 21 and bypass assembly 46. In all embodiments, the narrow strip may, for example, be about 10 cm to 25 cm wide. Next, a diverter 48 is actuated. The diverter 48 may, for example, be designed as a suction belt or vacuum belt and may be adjusted so that the path or direction of the strip of the fibrous web can be changed. The diverter 48 guides the strip into a rope guide 49. The rope guide 49 comprises a bypass rope guide 51, which can guide the strip along the bypass path 47. Additionally, the rope guide 49 comprises a compaction rope guide 52, which guides the strip into or through the compacting apparatus 21. The diverter 48 may now selectively insert the strip into the bypass rope guide 51 or the compaction rope guide 52. For example, the rope guide may be designed as follows: A first rope 53 and a second rope 54 run along the compaction rope guide 52, starting from the diverter 48. The first rope 53 and the second rope 54 run directly adjacent to each other in the direction of the compacting apparatus 21 and form the compaction rope guide 52 in this area. However, the first rope 53 and the second rope 54 do not run through the compaction nip 30 of the compacting apparatus 21, but rather pass laterally past the compacting apparatus 21. At the exit of the compaction nip 30, the strip is in turn conveyed by the compaction rope guide 52 in the direction of the downstream machine component. In this downstream area, the strip is guided by the first rope 53 and a fourth rope 56, which run directly adjacent to each other in that area. The bypass rope guide 51 comprises a third rope 55 and the fourth rope 56 in the area downstream of the diverter 48. The third rope 55 and the fourth rope 56 run directly adjacent to each other in this area and guide the strip along the bypass path 47 through the bypass assembly 46. In the present embodiment, in the area in which the strip is transferred to the components of the system downstream of the bypass assembly 46, the rope guide 49 is formed by the first rope 53 and the fourth rope 56. In all embodiments, it may be provided that the bypass rope guide 51 comprises a first rope pair, in particular the first rope 53 and the second rope 54. This first pair guides the strip of the fibrous web along the bypass path 47. In all embodiments, it may be provided that the compaction rope guide 52 comprises a second rope pair, in particular the third rope 55 and the fourth rope 56. This second pair guides the strip of the fibrous web through or into the compacting apparatus 21. In all embodiments, it may be provided that the rope guide 49 has a portion following the bypass rope guide 51 and following the compaction rope guide 52 running parallel thereto, in which the strip of the fibrous web is guided by a rope of the first rope pair and a rope of the second rope pair. In particular, in the present embodiment, the strip in this area is guided by the first rope 53 and the fourth rope 56. In all embodiments, the ropes 53, 54, 55, 56 are preferably all configured as endless ropes guided in a loop. In particular, one or more rope drives 57, 58 are provided for driving the ropes 53, 54, 55, 56. In the present embodiment, a first rope drive 57 and a second rope drive 58 are provided. In the present embodiment, the first rope drive 57 drives the second rope 54 and the third rope 55. In the present embodiment, the second rope drive 58 drives the first rope 53 and the fourth rope 56. In particular, it may be provided that a drive drives a rope of the first rope pair and a rope of the second rope pair. In particular, it may be provided that a further drive drives the second rope of the first rope pair and the second rope of the second rope pair. In the portion in which the bypass rope guide 51 and the compaction rope guide 52 are brought together, an adjusting roller 60 may be provided. As shown in enlarged detail, the adjusting roller 60, when actuated, shifts the position of at least one of the ropes 53, 54, 55, 56 in such a way that the strip of the fibrous web, depending on whether it comes from the bypass rope guide 51 or from the compaction rope guide 52, can be guided further along the rope guide 49 to the downstream system component. In the present embodiment, a deflection roller 59 is provided in this area. If the strip of the fibrous web is guided along the bypass rope guide 51, the third rope 55 is looped around the deflection roller 59 by the adjusting roller 60 in such a way that it is guided further between the first rope 53 and the fourth rope 56. If, on the other hand, the strip of the fibrous web comes out of the compaction rope guide 52, the adjusting roller 60 can displace a section of the third rope 55 in such a way that the strip can run unhindered from the compaction rope guide 52 into the further rope guide 49. In particular, a loop of the third rope 55 is pulled back by the adjusting roller 60.
Claims
1. A system for producing kraft paper, comprising the following system components:- a wire section (2) for forming a fibrous web by continuously applying a fibrous suspension along the machine flow direction (1) by a headbox (3),- a shaking apparatus (4) for shaking the fibrous web transversely to the machine flow direction (1), i.e. in the cross direction,- a press section (5) for pressing the fibrous web that has been partially dewatered in the wire section (2),- a dryer section (6) for drying the fibrous web,- a compacting apparatus (21), in particular a Clupak device, for compacting the fibrous web in the machine flow direction (1),- and a reeling station (7) for winding the paper web formed from the fibrous web,characterised- in that a bypass assembly (46) is provided for conveying the fibrous web along a bypass path (47), bypassing the compacting apparatus (21),- in that a rope guide (49) is provided for selectively guiding a strip of the fibrous web through the bypass assembly (46) or through the compacting apparatus (21),- in that the rope guide (49) comprises a bypass rope guide (51) for guiding the strip of the fibrous web through or into the bypass assembly (46) and a compaction rope guide (52) for guiding the strip of the fibrous web through or into the compacting apparatus (21),- and in that the bypass rope guide (51) and the compaction rope guide (52) are provided permanently and / or simultaneously adjacent to each other.
2. The system according to claim 1, characterised- in that the bypass assembly (46) is provided exclusively in the area of the compacting apparatus (21) and is designed for conveying the fibrous web by bypassing the compacting apparatus (21) but not by bypassing other system components,- in particular in that the compacting apparatus (21) is arranged along the machine flow direction (1) between a system component upstream of the compacting apparatus (21) and a system component downstream of thecompacting apparatus (21), and the bypass path (47) of the bypass assembly (46) extends from the exit of the upstream system component to the entrance of the downstream system component.
3. The system according to any one of claims 1 or 2, characterised- in that the dryer section (6) comprises a pre-dryer section (19) and an afterdryer section (20) arranged downstream of the pre-dryer section (19) along the machine flow direction (1),- in that the compacting apparatus (21) is arranged along the machine flow direction (1) between the pre-dryer section (19) and the after-dryer section (20),- and in that the bypass assembly (46) conveys or can convey the fibrous web from the pre-dryer section (19) to the after-dryer section (20), bypassing the compacting apparatus (21).
4. The system according to any one of claims 1 to 3, characterised in that- in that the bypass assembly (46) comprises an adjustable diverter (48) for selectively conveying the fibrous web or a strip of the fibrous web through the compacting apparatus (21) or through the bypass path (47),- wherein the diverter (48) is configured, for example, as an adjustable suction belt or vacuum belt.
5. The system according to claim 1 or 4, characterised- in that the bypass rope guide 51, for guiding the strip through or into the bypass assembly (46), comprises a first pair of ropes,- and in that the compaction rope guide (52) comprises a second pair of ropes for guiding the strip through or into the compacting apparatus (21).
6. The system according to one of claims 1 to 5, characterised- in that the rope guide (49) has a section with a further rope pair following the bypass rope guide (51) and following the compaction rope guide (52), for guiding the strip into the downstream component of the system.
7. The system according to any one of claims 1 to 6, characterised in that- in that one or more rope drives (57, 58) for driving the ropes of the rope guide (49), and in particular a first rope drive (57) and a second rope drive (58), are provided.
8. The system according to any one of claims 1 to 7, characterised in that the bypass assembly (46) is designed to convey the fibrous web at production speed, wherein the production speed exceeds 400 m / min, in particular exceeds 600 m / min.
9. The system according to any one of claims 1 to 8, characterised in that the width of the fibrous web exceeds 3.5 m, in particular exceeds 6 m.
10. The system according to any one of claims 1 to 9, characterised in that- in that the compacting apparatus (21), a circulating belt (26), a nip bar (33), a wrap roll (34) and a counter roll (28) are provided,- in that the compacting apparatus (21) has a compacting mode in which the circulating belt (26) is pressed towards the counter roll (28) by the nip bar (33) and in which the belt (26) wraps around the counter roll (28) over a wrap angle,- in that, in the compacting mode, a compaction nip (30) is formed between the belt (26) and the counter roll (28), which is designed to convey the fibrous web through it at production speed and thereby to compact it in the machine flow direction (1).
11. A method for operating a system for producing kraft paper, - wherein in a wire section (2), a fibrous web is formed by continuously applying a fibrous suspension along the machine flow direction (1) by a headbox (3),- wherein a shaking apparatus shakes the fibrous web transversely to the machine flow direction (1), i.e. in the cross direction,- wherein in a press section (5), the fibrous web that has been partially dewatered in the wire section (2) is pressed,- wherein the fibrous web is dried in a dryer section (6),- wherein in a reeling station (7), the paper web formed from the fibrous web iswound,characterised- in that in a compacting apparatus (21), in particular in a Clupak device, the fibrous web selectively passes through a compaction nip (30) provided between a belt (26) and a counter roll (28), is conveyed between the moving belt (26) and the moving counter roll (28), and thereby compacted in the machine flow direction (1),or is conveyed along a bypass path (47) via a bypass assembly (46), bypassing the compacting apparatus (21),- in that a strip of the fibrous web is selectively guided with a rope guide (49) through the bypass assembly (46) or through the compacting apparatus (21),- in that a bypass rope guide (51) of the rope guide guides the strip of the fibrous web through or into the bypass assembly (46) and a compaction rope guide (52) of the rope guide guides the strip of the fibrous web through or into the compacting (21) apparatus,- and in that the bypass rope guide (51) and the compaction rope guide (52) are provided permanently / simultaneously next to each other, but only selectively guide the strip of the fibrous web.
12. The method according to claim 11, characterised- in that the fibrous web is conveyed by the bypass assembly (46) by bypassing the compacting apparatus (21) but not by bypassing other system components,- in particular in that the compacting apparatus (21) is arranged along the machine flow direction (1) between a system component upstream of the compacting apparatus (21) and a system component downstream of the compacting apparatus (21), and the fibrous web is conveyed along the bypass path (47) of the bypass assembly (46) from the exit of the upstream system component to the entrance of the downstream system component.
13. The method according to any one of claims 11 or 12, characterised- in that the fibrous web is dried in a pre-dryer section (19) of the dryer section (6) and in an after-dryer section (20) of the dryer section (6) downstream of the pre-dryer section (19) along the machine flow direction (1),- in that the compacting apparatus (21) is arranged along the machine flow direction (1) between the pre-dryer section (19) and the after-dryer section (20),- and in that the bypass assembly (46) conveys or can convey the fibrous web from the pre-dryer section (19) to the after-dryer section (20), bypassing the compacting apparatus (21).
14. The method according to any one of claims 11 to 13, characterised- in that the bypass assembly (46) comprises an adjustable diverter (48) for selectively conveying the fibrous web or a strip of the fibrous web through the compacting apparatus (21) or through the bypass path (47),- wherein the diverter (48) is configured, for example, as an adjustable suction belt or vacuum belt.
15. The method according to any one of claims 11 to 14, characterised in that the bypass rope guide (51) guides the strip through or into the bypass assembly (46) with a first rope pair,- and in that the compaction rope guide (52) guides the strip through or into the compacting apparatus (21) with a second rope pair.
16. The method according to any one of claims 11 to 15, characterised- in that the rope guide (49) guides the strip into the downstream component of the system, following the bypass rope guide (51) and following the compaction rope guide (52), in a portion with a further rope pair.
17. The method according to any one of claims 11 to 16, characterised- in that the ropes of the rope guide (49) are driven by one or more rope drives (57, 58) and, in particular, by a first rope drive (57) and a second rope drive (58).
18. The method according to any one of claims 11 to 17, characterised in that the bypass assembly (46) conveys the fibrous web at production speed, wherein the production speed exceeds 400 m / min, in particular exceeds 600 m / min.
19. The method according to any one of claims 11 to 18, characterised in that the width of the fibrous web exceeds 3.5 m, in particular exceeds 6 m.
20. The method according to any one of claims 11 to 19, characterised- in that the compacting apparatus (21) a circulating belt (26), a nip bar (33), a wrap roll (34) and a counter roll (28) are provided,- in that the compacting apparatus (21) has a compacting mode in which the circulating belt (26) is pressed towards the counter roll (28) by the nip bar (33) and in which the belt (26) wraps around the counter roll (28) over a wrap angle,- in that, in the compacting mode, a compaction nip (30) is formed between the belt (26) and the counter roll (28), through which the fibrous web is conveyed at production speed and thereby compacted in the machine flow direction (1).
21. The method according to any one of claims 11 to 20, characterised- in that a first grade of kraft paper is produced when the fibrous web passes through the compacting apparatus (21),- and in that a second grade of kraft paper is produced when the fibrous web passes through the bypass assembly (46), bypassing the compacting apparatus (21), while optionally the compacting apparatus (21) is in maintenance.