MXPA98010424A - Hardened dividers in the transversal direction to the machine for a head box to make pa - Google Patents

Abstract

Improvements are provided in the internal dividers of a head box to make paper by hardening the dividers only in the cross machine direction. These divisors hardened in the cross machine direction provide a smooth and thin divider that is flexible in the machine direction and is still strong and resists distortion, or bending in the direction transverse to the machine.

Description

HARDENED DIVIDERS IN THE TRANSVERSAL DIRECTION TO THE MACHINE FOR A HEAD BOX TO MAKE PAPER Field of the Invention This invention relates to papermaking and is particularly directed to the dividers used in the head boxes for making paper in layers.

Background of the Invention The present invention is an advance in the art of papermaking. This invention allows paper and tissue in layers to be made more efficiently with a greater uniformity of basis weight in the cross machine direction.

In the manufacture of paper sheets, including creped tissue paper, a head box is used to deposit the papermaking furnish on a formed wire where the supply is partially dered to form paper tissue. In this process it is often advantageous to form the paper web in different layers of different fiber compositions. The head boxes in layers have internal dividers are well known in the art to achieve is objective. In some of these layered head boxes, the internal dividers end before the cutting opening. And others, these extend beyond the slice opening. Layered head boxes are described in United States Patent No. 3,843, 470 to Betley et al., In United States Patent No. 4,070.23 to Wahren, in the United States patent. United States Patent No. 4,141,788 to Justus, United States Patent No. 5,129,988 to Farrington, Jr., and United States Patent No. 5,133,836 to Alien, all of which are incorporated herein by reference .

Synthesis of the Invention Improvements in the internal dividers of a paper head box can be obtained by using reinforcing materials to harden them across their width, for example, in the cross machine direction. These hardened dividers can have a uniform surface and on which the supply can pass. These will resist the deformed or displaced across its width by the supply. Therefore, these will reduce the variations in the cross direction in the basis weight, which in turn will have many benefits, including an improved efficiency of the papermaking machine.

Therefore, in an embodiment of this invention a multi-layer head box is provided which comprises an upper wall having an upper lip and a lower wall having a lower lip. There is a space between the upper and lower lips forming a slit opening for the aqueous suspensions of the fibers for making paper out of the head box and a fin placed between the upper and lower walls. There is also a flexibl extended divider and reinforced in the cross-machine direction having one end up and one end down. The end face up being positioned within the end of the head box the end downward extends beyond the opening of the slice by from about 5 to 15 times the height of the opening.

In a further embodiment of this invention a head box for making paper is provided which comprises an inlet manifold, a duct diffuser tube bank and the upper and lower head box walls spaced apart. The upper wall having an upper labi, and the lower wall having a lower lip. The space between the upper and lower lips forms a slice opening so that the supply of the head box comes out. There is also a flexible divider in the head box which has the sections up, middle and down. The downward section constitutes no more than 30% of the total length of the divider with the upward end of the flexibl divider being adjacent to the passage diffuser tube bank and having the reinforcements located only in the downward section.

In another embodiment of this invention, it provides a flexible extended divider for use in a paper making head box comprising one end up and one end down, an upward end section corresponding to the upward end, a mid section located on one side and between the end section up and the section end down that correspond to the end down. The thickness of the splitter decreases from the end upwards to end downwards in a gradual and uniform taper. The hardening in the cross-machine direction of the end-down section being greater than or equal to hardening in the cross-machine direction of the upper and middle end sections, and the cross-machine direction hardening of the end section downwards increases from the point adjacent to the middle section to end downwards.

In still a further embodiment of this invention there is provided a machine head case divider for making paper hardened in the cross machine direction having one end up and one down, e where the hardening in the direction transverse to the machine and The hardening in the machine direction is inversely related as seen from the end to the top to the bottom end.

In still a further embodiment of this invention, a method for making a multi-layer paper comprising the acts of forming an aqueous solution of fibers for making paper, pumping the aqueous solution to a head box for making paper having an extended divider is provided. flexibl and reinforced there. The divisor has one end up and one end down. While it is in the head box, the aqueous solution flows over the divider from one end up to its downward end and the aqueous solution leaving the head box while still maintaining contact with the divider. The aqueous solution leaves the contact with the divider at its end downwards and leaves the divider as a free chorr. The free jet sticks in a forming zone of the papermaking machine, where the water is removed from the aqueous solution to form a wet fabric and also drains the wet fabric to form a sheet of paper. The divider while in contact with the aqueous solution after the aqueous solution left the headbox resists crimping and agglutination in the transverse direction to the machine thereby reducing variations in the transverse direction to the machine in the profile of the free jet and the variations of the base weight in the direction transverse to the machine.

In yet another embodiment of this invention, it provides a method for making paper comprising the form an aqueous solution of fibers for making paper, moving the aqueous solution of the fibers to make paper inside a head box for making paper, the aqueous solution of the fibers to make paper then leave the head box through a slice opening in the head box to form a free chorr and control the distribution in the transverse direction the machine of the aqueous solution of fibers to make paper in the free jet.

To assist in the understanding of the invention, one addresses the drawings and the detailed description of the presently preferred embodiments of the invention.

Brief Description of the Drawings Figure 1 is a schematic cross-sectional view of the forming zone of a process for making a conventional twin wire tis showing the ratio of the head box, the slice opening and the free jet relative to the forming roller and the roller chest.

Fig. 2 is a schematic cross-sectional view of the head box having an extended divider placed on one side of an apron lip.

Figure 3 is a schematic cross-sectional view of a head box having an extended divider disposed on one side of a lip of the headbox.

Figure 4 is a schematic cross-sectional view of a headbox having extended dividers positioned on one side of both lips of the headbox.

Figure 5 is a schematic transverse sectional view of a head box having the extensions d lip.

Figures 6A and 6B are plan views of an extended divider illustrating examples of placement of distribution of the fibers in the divider.

Figure 7A is a cross-sectional view of the extended divider illustrated in Figure 6A.

Detailed Description of the Presently Preferred Incorporations of the Invention Figure 1 is a schematic view in cross section of the forming area of a twin wire tis making machine. An aqueous suspension of papermaking fibers, which is referred to as a supply for paper or supply, is pumped to a headbox 1 by a fan pump (not shown).

The head box 1 has an upper head box wall 8 and a lower head box wall 9 These upper and lower walls extend to the length d the head box terminating the lips 10 and 11 respectively The space between these lips It is mentioned as the opening d slice. As used here, the length is synonymous with the machine direction and the width is synonymous with the cross direction to the machine of the paper making machine.

The head box 1 has three extended divisore, 16, 17 and 18 that extend through the head box and have the parts 2 extending beyond the slice opening. A free jet 3 of the aqueous suspensions of the paper fibers exit the end of the parts 2 into the space between the convergent forming surfaces defined by a forming roll 4 and the chest roll 5.

The forming roller is partially wrapped by a first forming wire or cloth 6 and the chest roll is partially wrapped by a second forming wire or cloth 7. The forming roller can be solid or vacuum assisted. Free jet can be about 1 inch thick can be from less than an inch to about 1 inch in length. The angle of the blow of the free jet at the impact point will vary depending on the forming process and the geometry of the forming section of the paper making machine.

A wet fabric of fibers is formed by removing the water from the aqueous suspension through the first and second forming wire. The wet tissue is then further processed in any suitable manner to produce tissue or paper. Such processing typically includes the further draining, drying, creping, rolling and converting to the desired product form.

Upstream of the slice opening the head box, illustrated in FIG. 1, is divided into several flow channels by the fins 12, 13, 14 and 15 and by means of the extended dividers, 16, 17 and 18. The fins serve torque to generate fine-scale turbulence in the head box. The fins terminate just above the slice opening of the head box at which point the flow is then divided into four flow channels by the dividers 16, 17 and 18. When not shown in Figure 1, the fins and the extended divisore may be rigidly fastened, flexibly pivotally at their ends upward in the headbox. The extended dividers 16, 17 and 18 have the parts 2 extending across the headbox slice opening and inside the headbox. space between the forming surfaces. In part 2, there are still three separate divisors 16, 17 and 18.

Due to the required thinness of the divisore extended at their tips, the extended dividers are very flexible. The walls of the head box, however, are rigid and their relative positions are fixed during operation, but they can be adjusted controllably by means of adjustment, such as a pivotable rod 19 shown attached to the lower head case lip. The typical convergence angles for the upper top box walls of the commercially available head layers can be from 15 degrees to 19 degrees.

As the aqueous solutions of paper-making fibers pass through the multiple flow channels d - the head box, these converge until they reach the region of the slice opening. At that point in the process, the flows pass rapidly in essentially parallel fashion to exit the slice opening. On exiting the slit opening flows, however, these are no longer confined by the rigid walls 8 and 9 of the headbox and are free to expand, bend and distort the extended dividers 16, 17 and 18. To control This bent and distortion across the width of the dividers, these are reinforced in a way that does not essentially affect its thinness and ability to bend in the machine direction, but which hardens it in the cross machine direction.

The use of the reinforcements to stretch the extended divisore provides a thin and smooth divider which is flexible in the machine direction but which is strong and resists distortion, or bending in the direction transverse to the machine, for example through its width. Reinforcements can be placed at any point along the length of the dividers as long as they are placed on the tip of the dividers. For example, reinforcements can be placed starting at or near the point where the fins terminate and extend to the downward end of the dividers, for example, the point where the stream of flow leaves the dividers. Reinforcements can also be placed starting at or slightly down from the slice opening and extending to the downward end of the dividers. Reinforcements can also be placed so that the length is essentially parallel to the direction transverse to the divider machine. .

The reinforcements do not restrict the ability of the dividers to fold into the slice opening in the head box along the flow streams. Therefore, they do not prevent the divider from flexing or moving upwards (in relation to the forming surfaces) as it may be caused by the flow currents. This characteristic in the direction of the machine is beneficial and is not significantly affected by the reinforcements. The reinforcements, however, harden the divider in the direction transverse to the machine, thereby restricting the capacity of the divider to bend in the direction transverse to the machine. This hardening will improve the purity of the layer and the formation of the layer. It will also reduce variations in the transverse direction to the machine in the basis weight of the paper or tissue, and thus provide a paper or tissue with a basis weight in the cross-machine direction consistent or uniform. The improved layer purity, formation and base weight profiles in the transverse direction to the machine will also improve the overall run, speed and efficiency of the paper making machine.

The location, quantity, type and pattern of reinforcements on the extended dividers will vary depending on the equipment used to make the paper and the product being made, including the number of dividers that are being used, the manner of the head box that is being used, the geometry of the forming area that is being used and the kind of paper or tissue that is being made. Additionally, the reinforcements may be located in all the extended dividers or in different places and different divisors within the same headbox. In addition, different types of reinforcements can be used in the same divider. By way of example, and not to limit the type of reinforcements that can be used, the reinforcements may be fibers, sheets, fabrics, wires or wires. Materials such as aramid (Kevlar), glass, graphite, nylon, and asbestos (and asbestos replacements) or metallic wire such as steel and aluminum can be used. Any other material that can be incorporated with the divider and that hardens it in the direction transverse to the machine and which can withstand the conditions in the paper making machine can be used as reinforcements. The manner and techniques of incorporating such reinforcements into the materials or matrix used to make the divider are known in the art and are examined by William P Callister., Jr. in the work Material Science and Engineering: An Introduction (1985, John Wiley & amp;; Sons), which is incorporated here by reference.

Figure 2 shows a head box having an input manifold 1, a diffuser-scaled tube bank 2, an upper wall 3 having an upper lip 4, a lower wall 5 having a lower lip 6, which extends beyond the upper lip to form a protective cover. The head box of figure 2 has the fins, 7, 8 and 9, and a flexible extended divider 10 which is rigidly fixed to diffuser tube-step bench 2. The flexible extended divider can be made of any material which can support the operating conditions of the head box, the flexion and response to the pressure of the fluid, and having the reinforcements attached to or incorporated in it. Such materials may include polyesters, epoxies, phenolics, silicones and nylon. Several materials that are useful as arrays for reinforcement are discussed in Callister as mentioned above which is incorporated by reference.

The thickness of the flexible extended divider can, for example, be about 0.40 inches at its upward extremity preferably tapering towards its tip. The flexible extended divider extends beyond the opening d sliced by a distance of from about once about 15 times the height of the slice opening. For example, the flexible extended divider may extend po about 6 inches or beyond a slice opening 0.5 inches into a tissue head box. The divisors are hardened in the direction transverse to the machine by the reinforcements that are placed in the area identified as A.

In Figure 3, there is shown a headbox having an input manifold 1, a diffuser-scaled tube bank 2, an upper wall 3 having an upper lip, a lower wall 5 having a lower lip 6, which ends around the same place down as the upper lip. The head box of Figure 3 has fins 7, 8 and 9 and a reinforced flexible spread divider 10. The reinforced flexible spread divider can be made from any suitable material as described above. The extended flexibl extends beyond the slice opening by a distance of about once to about fifteen times the height of the slice opening. The divider is hardened in the direction transverse to the machine by the reinforcements that are placed in the area identified as A.

In figure 4 there is shown a headbox having an input manifold 1, a bench diffuser tube 2, an upper wall 3 having an upper lip 4, a lower wall 5 having a lower lip 6, which ends around from the same place downwards than the upper lip. The head box of FIG. 4 has fins 7 and 8, and flexible extended dividers 9 and 10. The extended flexible dividers can be made of any suitable material as s described above. The flexible extended dividers extend beyond the slice opening by a distance of about once to about fifteen times the height of the slice opening. One or both of the divisore may be hardened in the direction transverse to the machine by the use of the reinforcements as described herein. The placement of the reinforcements can also be the same or different because of the divisors. The degree of rigidity in the direction transverse to the machine may be similarly or different for the divisors. In the embodiment shown in Figure 4, the reinforcements are placed in the areas identified as A on the top divider and B on the bottom divider.

In figure 5 a head box 1 d is shown a design similar to that shown in figure 1. In the head box of figure 5 the reinforced flexibl lip extensions 20 and 21 are cotérminas with the dividers extended from the box of head 16, 17 and 18. The lip extensions are reinforced in a manner similar to the reinforcement of the divisore as described above. The head box lip extensions can be attached to the head box by any suitable means, but in the embodiment incorporated in Fig. 6, these are around the lips of the head box 10 11 are supported by a top support 22 and a lower support 23. One, two or three of the extended headbox dividers can also be reinforced.

Figures 6A and 6B show, by way of example, patterns for the placement of the reinforcements in the extended divisore. These figures show a plan view of a head box of a type similar to that shown in Fig. 1. The head box 1 has a top head box wall 8 having an upper lip 10. The lower part of the head the head box wall 8 is cut on the score 8a to show the flexible spread 18 below it. The flexible spread 18 extends beyond the slice opening which is formed by the upper lip 10 a box lip lower head (not shown) to the end at its tip 18a. In the operation, the supply will flow from the left to the right as seen in these figures. Thus, the tip 18a will be the downward end of the flexible extended divider 18. The upstream end of the divider, which is not shown in these figures, will be located within the headbox at or around the point where the first supply enter the head box. The flexible extended dividers may be rigidly, flexibly or pivotally attached to the headbox at their ends upwards, by means well known in the art.

In the embodiment shown in Figures 6A and 7A, a multiplicity of reinforcing fibers 24 are positioned essentially parallel to the tip 18a of the flexible divider 18. The spacing between the reinforced fibers gradually decreases from the upward fibers located at or near the slice opening to the tip 18a, where they are spaced closely together. This placement or spacing of the reinforced fibers provides a reinforced flexible divider that is very flexible in the machine direction, while having a gradually decreasing flexibility in the cross machine direction from the opening of the slice to the tip. In addition, because the thickness of the extended divider is decreasing as it moves downward from the slice opening toward the tip, the rigidity in the machine direction will also decrease as it moves downwardly out of the slice opening. Therefore, the degree of flexibility in the direction of the machine is inversely related to the degree of flexibility in the transverse direction by moving one downward along the line from the slice opening to its tip. Figure 7a is a cross section of the reinforced flexible divider shown in Figure 6A. In this figure, the fibers 24 are pulled larger than their current relative size to the divider. The fibers can be much thinner and therefore they can be layered one on top of the other inside the divider.

Another embodiment of the spacing and positioning of the reinforcing materials is shown in Fig. 6B. In this figure, evenly spaced reinforcing materials 24 are shown which extend through the full width of the flexible excluded divider and the additional reinforcing materials 25 interspaced between the fibers of material 24.

Although the invention has been described in connection with certain currently preferred embodiments, those skilled in the art will recognize modifications to the structures, arrangements, parts, elements, component materials which may be used in the practice of this invention without departing from the principles Of the same.

Claims (39)

1. R E I V I N D I C A C I O N S 1 . A multi-layer headbox comprising (a) an upper wall having an upper labi and a lower wall having a lower lip; (b) a space between the lower upper lips forming a slice opening for the aqueous suspensions of the papermaking fibers to exit the headbox; Y (c) a flexible extended divider reinforced in the direction transverse to the machine having one end up and one end down, the down end being placed inside the head box, the end downward extending beyond the opening of the head. slice by de desd about 5 to 15 times the height of that opening.
2. 2. The head box as claimed in clause 1, characterized in that it has a reinforced flexible labi extension attached to at least one of the head box.
3. 3. The head box as claimed in clause 1, characterized in that the flexibl and reinforced stretched divider is reinforced with graphite fibers only at the end downwards.
4. 4. The head box as claimed in clause 1, characterized in that it has a second flexible divider reinforced in the direction transverse to the machine; The second flexible divider reinforced in the transverse direction the machine has one end up and one end down, the down end extends beyond the slice aperture for about 5 to 15 times the height of the slice opening; both reinforced flexible dividers have a hardening in the direction transverse to the machine increasing from the end up to the end down and a rigidity in the machine direction decreasing from the end up to the end down.
5. 5. The head box as claimed in clause 4, characterized in that the flexibl extended divider is reinforced with graphite fibers.
6. 6. The head box as claimed in clauses 1 or 4, characterized in that the flexible extended divider is reinforced with glass fibers.
7. 7. The head box as claimed in clauses 1 or 4, characterized in that the flexible extended divider is reinforced with a metal wire.
8. 8. The head box as claimed in e-clauses 1 or 4, characterized in that the flexible extended divider is reinforced with aramid.
9. 9. The head box as claimed in clauses 1 or 4, characterized in that the flexible extended divider is reinforced with nylon.
10. 10. A head box for paper making machine that includes: (a) a multiple entry; (b) a bank of step diffuser tube; (c) the lower upper head box walls spaced apart; (d) the upper wall having a upper lip and the lower wall having a lower lip; (e) the space between the lower upper lips forming a slice opening; (f) a flexible splitter; (g) the divisor having the sections up, middle and down, the section down constitutes more than 30% of the total length of the divisor; (h) the upstream end of the divider flexib being on one side of the bench diffuser tube; Y (i) the reinforcements located only on the downward section of the divider.
11. 11. The head box as claimed in clause 10, characterized in that it has a reinforced flexible lab extension attached to at least one of the head box lips.
12. 12. The head box as claimed in clause 10, characterized in that the downward end d flexible divider extends beyond the slice opening by about 5 to 15 times the height of the slice opening.
13. 13. The head box as claimed in clause 10, characterized in that the extension of the flexible labi fastened to at least one of the head box lips and in which the downward end of the flexibl divider extends beyond the slice opening.
14. 14. The head box as claimed in clauses 10, 11, 12 or 13, characterized in that the divider is reinforced with graphite fibers. .fifteen.
15. The head box as claimed in clauses 10, 11, 12 or 13, characterized in that the divider is reinforced with glass fibers.
16. 16. The head box as claimed in clauses 10, 11, 12 or 13, characterized in that the flexible extended divider is reinforced with metal wire.
17. 17. The head box as claimed in clauses 10, 11, 12 or 13, characterized in that the flexible extended divider is reinforced with aramid.
18. 18. The head box as claimed in clauses 10, 11, 12 or 13, characterized in that the flexible extended divider is reinforced with nylon.
19. 19. A flexible extended divider for use in a head box for making paper comprising: one end up and one end down; an upward extremity section corresponding to the upward end, a middle section located on one side and between the end section upwards and a downstream end section corresponding to end downwards; the thickness of the divider decreases from the end upwards to the end downwards in a gradual and uniform ahusamient; the hardening in the transverse direction to the machine of the end-down section being may or equal to the hardening in the transverse direction to the machine of the middle and end-up sections; and hardening in the transverse direction of the downstream end section d increasing from the adjacent point of the middle section to the downward end.
20. 20. The head box as claimed in clause 19, characterized in that the divider is reinforced with graphite fibers.
21. 21. The head box as claimed in clause 19, characterized in that the divider is reinforced with glass fibers.
22. 22. The head box as claimed in clause 19, characterized in that the flexible extended divider is reinforced with metal wire. "
23. 23. The head box as claimed in clause 19, characterized in that the flexible extended divider is reinforced with aramid.
24. 24. The head box as claimed in clause 19, characterized in that the flexible extended divider is reinforced with nylon.
25. 25. A head box divider for machine to make paper hardened in the direction transverse to the machine having one end up and one down, where the hardening in the direction transverse to the machine and hardening in the machine direction are inversely related as seen from the extreme up to the extrem low.
26. 26. The head box as claimed in clause 25, characterized in that the divider is reinforced with the graphite fibers.
27. 27. The head box as claimed in clause 25, characterized in that the divider is reinforced with the glass fibers.
28. 28. The head box as claimed in clause 25, characterized in that the flexible extended divider is reinforced with metal wire.
29. 29. The head box as claimed in clause 25, characterized in that the flexible extended divider is reinforced with aramid.
30. 30. The head box as claimed in clause 25, characterized in that the flexible extended divider is reinforced with nylon.
31. 31. A method for making paper using the currency as claimed in clauses 19, 20, 21, 22, 23, 24.
32. 32. A method for making paper that uses the currency as claimed in clauses 25, 26, 27, 28, 29 30.
33. 33. A method for making a multi-layer paper comprising the acts of: a) forming an aqueous solution of paper-making fibers; (b) pumping the aqueous solution to the head box to make paper having a flexibl extended divider reinforced there; (c) the divisor has one end up and one end down; (d) while in the head box, the aqueous solution flows over the splitter from its upper end to its downward end. (e) the aqueous solution leaves the headbox while remaining in contact with the divider. (f) the aqueous solution leaves the contact with the divider at its downward end and exits from the divider as a free jet. (g) the free jet strikes a forming zone of the paper making machine, where the water is removed the aqueous solution to form a wet weave and also drains the wet tissue to form a sheet of paper; and (h) the divider while in contact with the aqueous solution after the aqueous solution leaves the head box resists bending and bonding in the transverse direction to the machine thereby reducing variations in the transverse direction to the machine. the machine in the profile of the free jet and the variations in the base weight in the cross machine direction.
34. 34. The method as claimed in clause 33, characterized in that the divider is reinforced with graphite fibers.
35. 35. The method as claimed in clause 33, characterized in that the divider is reinforced with glass fibers.
36. 36. The method as claimed in clause 33, characterized in that the divider is reinforced with metal wire.
37. 37. The method as claimed in clause 33, characterized in that the divider is reinforced c aramid.
38. 38. The method as claimed in clause 33, characterized in that the divider is reinforced with nylon.
39. 39. A method for making paper that includes: (a) forming an aqueous solution of fibers to make paper; (b) moving the aqueous solution of the fibers to make paper to a head box for making paper; (c) the aqueous solution of fibers for making paper then leaves the head through a slit opening in the head box to form a free jet; Y (d) controlling the distribution in the cross-machine direction of the aqueous solution of the fibers to make paper in the free jet. SUMMARY Improvements are provided in the internal divisore of a head box to make paper by hardening the dividers only in the transverse direction to the machine. These splitters hardened in the machine transverse direction provide a smooth and thin divider that is flexible in the machine direction and is still strong and resist distortion, or bending in the transverse direction to the machine.