Methods used in pulp dryers and cutting devices for pulp dryers

Abstract

This invention relates to a method for use in a pulp dryer and a cutting device for the pulp dryer. The method includes forming (10) a pulp web (14), and pressing (11) and drying (12). The method then includes slicing the formed pulp web (14) into sheets (24) and stacking the sheets (24) into bales (32). The method also includes monitoring the production of the pulp web (14). According to the method, any discontinuity in production is detected by monitoring, but slicing (13) of the remaining pulp web (14) continues until slicing (13) is stopped.

Description

Technical Field

[0001] This invention relates to a method for use in a pulp dryer, comprising forming a pulp web, pressing and drying it, then slicing the formed pulp web into sheets, stacking the sheets into bales, and monitoring the production of the pulp web. The invention also relates to a cutting device for a pulp dryer. Background Technology

[0002] The formation of the pulp web is a lengthy process involving several consecutive stages. During and between each stage, the pulp web may break, or production may have to stop abruptly for other reasons. During a web breakage, the pulp travels to a breakage treatment point in the wet and dry ends, the breakage is removed, and production resumes. Operators monitor the production process.

[0003] Web breakage is more likely to occur in the production stages before the drying chamber than within it. In other words, the pulp web is still wet during forming and pressing. The drying chamber is also large, holding hundreds of meters of pulp web. However, information about web breakage during forming or pressing is delayed or not transmitted to the slicer after the pulp dryer at all. After breakage, the pulp web travels to the pulper after the drying chamber, and the slicer is stopped. If the delay is long, problems can also occur in the slicer. Moreover, a large amount of pulp web must travel to the pulper to empty the pulp dryer before production can resume. Summary of the Invention

[0004] The object of this invention is to provide a new method for use in a pulp dryer that is more economical, safer, and easier to implement than previous methods. Another object of this invention is to provide a new cutting device for a pulp dryer that can stably and quickly cut narrow strips of pulp. According to the invention, a method for use in a pulp dryer is provided, comprising: forming a pulp web, pressing and drying it, then slicing the formed pulp web into sheets, stacking the sheets into bales, and monitoring the production of the pulp web, continuing to slice the remaining pulp web even if any discontinuity in production is detected by the monitoring, until slicing is stopped. According to the invention, a cutting device for a pulp dryer is also provided, comprising a support for a pressure roller and a blade operated by an actuator for cutting narrow strips separated from the full-width pulp web. This method can significantly reduce the amount of breakage. This increases pulp yield, thereby improving profits. Simultaneously, the downtime of the pulp dryer is reduced, and production can be stopped and restarted with low labor costs. Moreover, the stop can be completely controlled. This further reduces downtime and prevents damage to the equipment. The cutting device is robust and easy to install into the pulp dryer. Attached Figure Description

[0005] The present invention will now be described in detail with reference to the accompanying drawings, which illustrate some embodiments of the invention, wherein:

[0006] Figure 1 The front side view of the pulp dryer is shown.

[0007] Figure 2 It shows Figure 1 A magnified view of a portion of the image, showing a slicer used for the slurry web.

[0008] Figure 3a This illustrates the start of stopping the slicer according to the invention.

[0009] Figure 3b The separation of narrow strips of the paste web is shown.

[0010] Figure 3c This illustrates introducing a cutting device at the top of the strip.

[0011] Figure 3d This shows the beginning of the bar's unfolding.

[0012] Figure 3e The extended end of the strip is shown.

[0013] Figure 4 The stop period is shown Figure 2 slicer

[0014] Figure 5a The cutting device according to the invention during normal production is shown.

[0015] Figure 5b Showing the state before disconnection Figure 5a The cutting device

[0016] Figure 5c It shows exactly after the disconnection Figure 5a The cutting device. Detailed Implementation

[0017] Figure 1A schematic side view of a pulp dryer utilizing the method and cutting apparatus according to the invention is shown. The pulp dryer sequentially comprises a forming section 10, a pressing section 11, and a drying chamber 12, and finally a slicer 13 for the freshly produced pulp web 14. In the forming section 10, aqueous pulp is fed onto a wire section 15 via a headbox 16. The pulp web 14 is formed on the forming section 10 by removing water. The pulp web is then pressed multiple times in the pressing section 11 to remove more water. After the pressing section 11, the pulp web 14 is guided to the drying chamber 12 by an open traction section. Subsequently, the forming section is equivalent to forming, the pressing section is equivalent to pressing, the drying chamber is equivalent to drying, and the slicer is equivalent to slicing. The same reference numerals are used accordingly.

[0018] The drying chamber 12 has a hood 17, which includes superposed drying plates. Figure 1 Only a small portion of drying chamber 12 is shown. Each drying plate has rotating rollers at both ends and an air-blowing box between them. In an airborne drying chamber, the pulp web travels horizontally via the drying plates in a zigzag pattern. Between the rotating rollers, air blown from the air-blowing box supports and dries the pulp web. Thus, the pulp web moves over an air layer. Typically, the pulp web enters from the top of shroud 17 and exits at the bottom of the opposite ends. The height of the drying plates depends primarily on the required air volume and the width of the pulp web. The wider the pulp web, the higher the air-blowing box and the higher the drying plate. In practice, the height of the drying plates is 250mm-800mm, and there are typically 10-30 drying plates in a single drying chamber.

[0019] In a slicing machine, a uniform, full-width strip is first cut into sheets along the longitudinal direction and then along the transverse direction, after which it is stacked into bales. Figure 1 And especially Figure 2 The slicer 13 in operation is shown. The slicer is used for pulp web produced by the pulp dryer as described above. Between the drying chamber 12 and the slicer 13 is a pull press 18 and a pulper 19. The pull press pulls the entire pulp web out of the drying chamber. Here, a scanner 20 is provided before the pull press 18 for determining the properties of the pulp web 14. Figure 1 If the pulp fabric breaks at some point, it travels downwards to pulper 19, and the remaining pulp fabric is pulled out of the drying chamber by traction pressing. During the emptying of the drying chamber, the slicer is stopped and cleaned if necessary. Another pulper 19' is also present to handle breaks from press section 11 and drying chamber 12.

[0020] The slitter 13 comprises a slitter 21, a cross cutter 22, and a layboy conveyor 23 for overlapping the cut sheets 24 before the packing table 25. The slitter 21 includes a plurality of parallel blades 26 arranged against a bottom slitter 27. As the pulp web 14 travels through the slitter 21, it forms a plurality of strips. From there, these strips are pulled by a feed press 28 and further pushed to the cross cutter 22. In other words, the slitter 21 longitudinally cuts the pulp web 14 into parallel strips, which are then cross-cut into sheets 24 by a rotating cutting roller 29 with cross-cutting blades 30 and stationary reverse blades 31. These sheets are then stacked by the layboy conveyor 23 and sent to the packing table 25 in bundles. The packing table descends gradually until the packing is complete.

[0021] This method is implemented in a pulp dryer and includes forming a pulp web 14, then pressing and drying the pulp web 12, and finally slicing the formed pulp web 14 into sheets 24 and stacking them into bales 32. Slicing occurs in a slicer 13. Furthermore, the method includes monitoring the production of the pulp web 14. According to the invention, even if any discontinuity in production is detected by monitoring, slicing of the remaining pulp web 14 continues until slicing is stopped. In other words, despite the discontinuity in production, slicing continues and the sheets are packaged. In this way, more bales are produced, thereby reducing breakage. Moreover, less pulp remains in the drying chamber, saving cleaning time for the pulp dryer in case of breakage. In practice, a breakage detector at the wet end initiates a stop sequence that includes the continued slicing and the subsequent stop.

[0022] The method also includes monitoring the forming 10 and pressing 11 of the web 14. In other words, the forming and pressing sections are monitored because these stages are the most vulnerable. When web breakage occurs, a trigger is detected to stop the slicer. Similarly, slicing continues despite the trigger. But now the trigger information is received without delay, so production and the slicer can be stopped in a controlled manner.

[0023] The trigger could be a visual observation by the operator when web breakage occurs. The operator then initiates the necessary actions to reduce production. Alternatively or additionally, the method includes selecting a signal from the control system 33 contained within the pulp dryer as the trigger. Web breakage can be detected using one or more sensors, probes, etc.

[0024] In practice, the method still involves continuing slicing 13 until the next set of unfinished packages 32 is ready. In other words, at least the unfinished packages are completed. Thus, a suitable set of packages is obtained, and they can be shipped to the market at full price. When the packages are ready, the slicer is stopped if necessary, and production resumes later.

[0025] On the other hand, the method involves determining the amount of remaining pulp web 14 and continuing slicing 13 until groups of packages 32 based on the determined amount are ready, or as long as the pulp web remains taut to prevent it from traveling laterally. For slicing to be performed, the pulp web should have a certain tension. In practice, the performance of the pulp dryer is known in advance. In other words, it can be determined how much pulp web is in the drying chamber when the web breaks. Slicing and packing of several groups of packages then continues until the drying chamber is almost empty. In practice, depending on the pulp dryer discussed, up to three or four groups can even be completed.

[0026] As previously mentioned, the operator can initiate a production stop. Advantageously, the stop is arranged as an automatic sequence. In practice, when the control system detects web breakage, all or at least most of the necessary actions are performed automatically. At the end of the pulp dryer, i.e., after the drying chamber, the steps are as follows.

[0027] The method involves, during a pause, first separating narrow strips 34 from the full-width slurry web 14. Typically, the separated strips 34 are 50-300 mm wide. In practice, the method includes separating the strips 34 by waterjet cutting or mechanical cutting. Figure 1 The location of the waterjet cutting machine is indicated by an arrow. Figure 3a In the middle, the waterjet cutter 35 is moved to the edge of the slurry web 14. Then the waterjet cutter 35 begins cutting, separating narrow strips 34. Figure 3b The remaining strips and webs are still being pulled to the cutter. Slicing and packing can also continue. However, before actual stopping, the method involves opening the waste door 36 located after slice 13. This is in Figure 4 As shown, the cut sheet 24 is guided downward toward the pulper 19. Here, the narrow strip 34 is cut off and falls toward the pulper 19.

[0028] Next, the method includes breaking the strip 34 before slicing 13, and fully unfolding the strip 34 again while pulling it downwards before slicing 13. The strip 34 is broken between the traction press 18 arranged before slicing 13 and the feed press 28 contained in slicing 13. Here, the method includes breaking the strip 34 on the feed roller 37 arranged between the traction press 18 and the feed press 28. In this position, both the strip and the pulp web are under tension, which facilitates the breaking. Before actual breaking, the method includes pressing a movable pressure roller 38 against the feed roller 37, the movable pressure roller having a width corresponding to the strip 34. Figure 3c In this process, the pressure roller 38 is pressed against the feed roller 37. Therefore, the narrow strip travels through the pressure zone formed by the pressure roller and the feed roller. In this way, the strip travels steadily before breaking.

[0029] Finally, the method involves impacting the strip 34 before the feed roller 37. In other words, the strip is broken by impact, here by impacting the strip 34 using a blade 39 operated by an actuator. Figure 3d In the middle, the strip travels downwards to the pulper 19, while the remaining pulp fabric 14 continues to the slicer 13. Then, the waterjet cutter 35 moves towards the other edge of the pulp fabric (here from left to right). Thus, the narrow strip gradually widens, while the rest of the pulp fabric narrows. During the widening process, the strip travels downwards to the pulper. Figure 3e In the middle, the strip almost completely widens. When the waterjet cutter reaches the edge of the slurry web, the entire slurry web travels downwards into the pulper, and nothing enters the slicer, so that the slicer can be stopped or at least cleaned before production resumes.

[0030] exist Figure 5a In the process, the slurry 14 travels normally via the feed roller 37. The cutting device here includes a pressure roller 38 with blades 39. This unit is supported to a bracket 41 by a hinged arm 40. The upper part of this unit is connected to the bracket 41 via a cylinder 42. Therefore, the pressure roller 38 can be easily pressed against the feed roller 37 using the cylinder 42. Figure 5b Then, via actuator 43, the blade 39 is pushed into the narrow strip 34. Figure 5cThe narrow strips are cut off. In other words, the cutting device includes a support 41 supporting the pressure roller 38 and a blade 39 operated by an actuator for cutting off the narrow strips 34 separated from the full-width pulp web 14. Furthermore, the pressure roller 38 is supported to the support 41 by a hinged arm 40 and a cylinder 42. The unit also includes a guard 49, which protects the cutting equipment and the user from injury by the blade. The cutting device shown is compact and robust. It can be easily automated, and the narrow strips are cut steadily. The device operates rapidly, so the slicer can be stopped quickly but still controlled. After stopping, the pressure roller is lifted. The blade is preferably a serrated impact blade that extends laterally across the separated narrow strips. Furthermore, the cutting device can even be easily installed on older pulp dryers.

[0031] The paper conveyor belt 23 includes several independent sets 44 of support rollers 45, which are arranged opposite to pressure rollers 46. Each feed roller has a set of pressure rollers. In this way, a pressure zone is formed between the support rollers and the pressure rollers. When the support rollers are driven, the sheet moves forward. Figure 2 As shown, at the first group 44, sheet 24 has already been partially stacked. For the next few groups, the sheets are further stacked, and finally at the packing table 25, the sheets are stacked together to form a package. After the packing table, the package is wrapped and usually also tied up, and then transported forward.

[0032] There is also a waste door 36 positioned below the paper conveyor belt 23. Upon stopping, the sheet will fall through the waste door 36, and then onto the break slide 47. Using the method according to the invention, the stopping of the slicing machine is newly arranged, and the slitter 21 and cross-cutting machine 22 can be arranged within a safety fence 48. This improves occupational safety and reduces waste. Simultaneously, the cross-cutting machine can also be reversible. In normal production, the sheet speed decreases after the stacking step, so that the leading edge of each sheet is placed on the trailing edge of the previous sheet, resulting in the sheets partially overlapping each other.

Claims

1. A method for use in a pulp dryer, comprising: Forming (10) a pulp web (14) and pressing (11), drying (12), then slicing (13) the formed pulp web (14) into sheets (24), piling the sheets (24) into bales (32), and monitoring the production of the pulp web (14), characterized in that even if any discontinuity in the forming (10) or the pressing (11) is detected by the monitoring, the slicing (13) of the remaining pulp web (14) is continued until at least the unfinished bale is completed.

2. The method of claim 1, wherein, Monitoring the forming (10) and the pressing (11) of the pulp web (14).

3. The method of claim 1, wherein, The signal from the control system (33) included in the pulp dryer is selected as the trigger.

4. The method of claim 2, wherein, The signal from the control system (33) included in the pulp dryer is selected as the trigger.

5. The method according to any one of claims 1 to 4, characterized in that, The amount of the remaining pulp web (14) is determined and the slicing (13) is continued until the group of bales (32) based on the determined amount is ready.

6. The method according to any one of claims 1 to 4, characterized in that, The slicing (13) is stopped after the unfinished bale is completed, and the stopping is arranged to be carried out automatically as a necessary action.

7. The method of claim 5, wherein, The slicing (13) is stopped after the unfinished bale is completed, and the stopping is arranged to be carried out automatically as a necessary action.

8. The method according to any one of claims 1 to 4, characterized in that, The slicing (13) is stopped after the unfinished bale is completed, and during the stopping, a narrow strip (34) is separated from the full-width pulp web (14), the strip (34) is disconnected before the slicing (13), and the strip (34) is again fully unfolded while being pulled down before the slicing (13).

9. The method of claim 5, wherein, The slicing (13) is stopped after the unfinished bale is completed, and during the stopping, a narrow strip (34) is separated from the full-width pulp web (14), the strip (34) is disconnected before the slicing (13), and the strip (34) is again fully unfolded while being pulled down before the slicing (13).

10. The method of claim 6, wherein, The slicing (13) is stopped after the unfinished bale is completed, and during the stopping, a narrow strip (34) is separated from the full-width pulp web (14), the strip (34) is disconnected before the slicing (13), and the strip (34) is again fully unfolded while being pulled down before the slicing (13).

11. The method of claim 7, wherein, The slicing (13) is stopped after the unfinished bale is completed, and during the stopping, a narrow strip (34) is separated from the full-width pulp web (14), the strip (34) is disconnected before the slicing (13), and the strip (34) is again fully unfolded while being pulled down before the slicing (13).

12. The method of claim 8, wherein, The strip (34) is disconnected between the pulling press (18) arranged before the slicing (13) and the feed press (28) included in the slicing (13).

13. The method of claim 12, wherein, The strip (34) is disconnected on a feed roll (37) arranged between the pulling press (18) and the feed press (28).

14. The method of claim 13, wherein, Before said disconnection, a movable press wheel (38) is pressed against said feed roller (37), said movable press wheel having a width corresponding to said strip (34).

15. The method according to claim 13 or 14, characterized in that, Said strip (34) is hit before said feed roller (37).

16. The method of claim 8, wherein, Said separated strip (34) has a width of 50-300 mm.

17. The method of claim 12, wherein, Said separated strip (34) has a width of 50-300 mm.

18. The method of claim 13, wherein, Said separated strip (34) has a width of 50-300 mm.

19. The method of any one of claims 1 to 4, wherein, Said cut (13) is stopped after the completion of the unfinished coating, and before said stopping, a reject gate (36) arranged after said cut (13) is opened.

20. Cutting device for a pulp dryer, characterized in that Said pulp dryer employs a method according to any one of claims 1-19, said cutting device comprising a support (41) supporting a press wheel (38) and a blade (39) operated by an actuator for truncating a narrow strip (34) separated from a full-width pulp web (14).

21. The cutting device of claim 20, wherein, Said press wheel (38) is supported to said support (41) by a hinged arm (40) and a gas cylinder (42).

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