JPH06322691A - Twin wire former of paper machine - Google Patents

Abstract

PURPOSE:To provide a twin wire former capable of making paper having uniform degree of fiber orientation between the top and reverse faces and in the direction of thickness and adjusting the degree of dehydration. CONSTITUTION:A paper slurry 2 discharged from a head box 1 is pressed between a pair of loop-forming dehydration wires 3, 4 and dehydrated to form a wet paper. Dehydration blade groups 6 and 5 are placed opposite to each other in the initial dehydration region of the wires 3, 4. The dehydration blade group 5 placed in the upper top wire loop 4 is made to be shiftable in longitudinal and vertical directions relative to the running direction of the wire. The distance between the wires is restricted and the dehydration pressure is varied by the shift of the dehydration blade group 5. The dehydration blade 5a of the dehydration blade group 5 is removable and the degree of dehydration can be varied by changing the number of the dehydration blades. The 1st forming shoe 7 is shiftable in the direction perpendicular to the wire to enable the adjustment of the degree of dehydration at the part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin wire former for a paper machine which forms a wet paper web between two wires.

[0002]

2. Description of the Related Art In a twin wire former of a paper machine, two wires each form a loop, and while the stock material solution is sandwiched between the two wires to run, water is removed from the solution by various dehydrating devices. The fiber mat is gradually grown by removing the so that the web is formed. FIG. 7 shows a typical present twin wire former. FIG. 7A
In, the jet 22 of the stock raw material liquid ejected from the head box 21 lands on the wire 23 before the first dewatering blade 27a of the dewatering blade group body 27 which is usually called a forming shoe, and then the first dewatering blade 7a. When the wire 23 is sandwiched between the two wires 23 and 24 that converge above, the wire 23 unsupported section between the first dehydration blade 27a of the dehydration blade group main body 27 and the dehydration blade 27b subsequent thereto due to the pressure generated by the tension of the wire 24. And at these blade bearing surfaces, the wire 24 is dehydrated to the opposite side.

Dehydration blade group body 2 shown in FIG. 7 (b).
7 (dehydration blade group body 27 is shown sideways)
The present invention was made by the present inventors (Japanese Patent Application No. 03-144742).
By focusing on the function of each dewatering blade of the dewatering blade group main body 27, the dewatering blade group main body 27 is divided into three zones, each of which has a unique function. That is, the wire 23 support surface of the first first zone of the dehydration zone following the first dehydration blade 27a has convex curvatures R ₁ and R ₂ ,
3 the wire 23 at the tip of the dehydration blade 27b, which is the supporting surface.
The blade 27 can be surely scraped off and the white water 31 entrained in the wire 23 can be scraped off at the blade tip.
It is possible to prevent a harmful effect due to the white water 31 entering between the wire b and the wire 23.

The wire 23 supporting surface in the dehydrating second zone following the first zone is formed in a flat shape. Final third
The wire 23 supporting surface of the zone is formed by the first dewatering blade 2
It is formed so as to have a curvature R _{3 in the} same direction as 7a, and the wire is reliably supported on the exit side of the dehydration section to ensure stable running. In the disposition of the dehydration blade group 27, the disposition of the dehydration blade group 7 is the same regardless of the papermaking conditions, so that the dehydration amount by the dehydration blade group 7 can hardly be adjusted.

On the other hand, in the case of a former called a hybrid former or an on-top former, FIG.
The configuration shown in (1) is proposed in Japanese Patent Application No. 63-144910. That is, the stock raw material liquid 42 ejected from the head box 41 is dehydrated on a bottom wire 43 called a Fourdrinier part to grow a fiber mat on the wire and sandwiched between the top wires 44 while forming a web, and forming. The roll 46, the opposing dewatering blade group 45, the solid roll 47, etc. are further dehydrated to form a paper layer.

[0006] In the twin wire former, which is currently the mainstream, the formation is improved because a strong shearing effect by the dewatering blade acts in the paper layer forming process, but the orientation of the fibers in the wire running direction (machine direction) is improved. It has the feature of producing high-quality paper. This high degree of fiber orientation in the wire direction is not desirable for printing paper that requires high dimensional stability and rigidity in the paper width direction, and the twin wire former is used when the strictest quality is required. It may not be done.

Further, the only method for changing the dewatering ability of the dewatering blade group accompanying the change in the papermaking conditions is to use vacuum suction dewatering, which is commonly used. As described above, as a means for changing the dehydration capacity and a means for improving the formation, there is an example of the dehydration blades that are opposed to each other in the hybrid former (on-top former). After that, since the dewatering blade gives a strong shearing effect, the formation is improved, but there is a problem that the orientation of the fibers is increased in the wire traveling direction.

[0008]

Therefore, the present invention, while being a twin wire former, has a low degree of fiber orientation required by the market, a small difference in the degree of fiber orientation between anisotropy and front and back, and a fiber in the thickness direction. An object of the present invention is to provide a twin wire former capable of making paper having a uniform orientation distribution and adjusting the dehydration amount arbitrarily.

[0009]

DISCLOSURE OF THE INVENTION The present invention is directed to a twin wire former for forming a wet paper web by sandwiching a stock material ejected from a headbox with a dehydration wire forming two loops and dehydrating between the wires. In order to solve the problem in, while providing a dewatering zone having a plurality of dewatering blades on the upstream side in one wire loop, the dewatering blade unit facing the dewatering zone in the other wire loop is reduced in the vertical and front and rear directions. Both of them will be configured so that they can be moved to either side.

Further, in the present invention, at least a part of the dewatering blade of this dewatering blade unit can be attached and detached, and the number of blades in the dewatering blade unit can be varied.

Furthermore, the present invention also employs a structure in which the dehydration blade on the dehydration zone side facing the movable dehydration blade unit is movable in the direction orthogonal to the wire.

Further, in the present invention, the above-mentioned dehydration blade unit is formed by a plurality of blade units,
A configuration is also adopted in which each of the units is independently movable in the wire traveling direction.

[0013]

In the twin wire former according to the present invention, one of the opposing dewatering blade groups arranged in the two wire loops is sandwiched between the two wires for converging the stock raw material liquid, and one of the opposing dewatering blade groups is operated in the vertical direction and the front-back direction. By adjusting at least one of them, the spacing between the wires can be arbitrarily changed in the area where the wet paper is not formed on the wires, thereby changing the shearing effect and the dehydration pressure and changing / adjusting the dehydration amount. it can. Furthermore, it becomes possible to adjust the concentration of the raw material entering the subsequent forming shoe group, keep the fiber dispersion capacity of the forming shoe at an optimum level, and evenly disperse the fibers evenly dispersed in the headbox on the front and back sides before re-flocking. Can be formed as a paper layer in a state of being uniformly dispersed.

Further, according to the present invention, at least a part of the dewatering blade in the dewatering blade unit can be attached and detached, and the number of blades in the dewatering blade unit can be varied. Can be adjusted, and the shearing effect of the dewatering blade can be adjusted to form a paper layer in which fibers are uniformly dispersed.

Furthermore, according to the present invention, the dewatering blade on the side of the dewatering zone facing the dewatering blade unit, which can be adjusted in at least one of the vertical and longitudinal directions, can be moved in the direction orthogonal to the wire. With this, it is possible to adjust the fiber dispersion there and the amount of dehydration from the stock material liquid.

Further, in the case where the dewatering blade unit is formed by a plurality of blade units and each unit can be independently moved in the wire traveling direction, the paper stock sandwiched between the two wires is used. The pulse pressure can be applied to the raw material liquid by arbitrarily changing the pitch and the size of the pulse pressure. By controlling the pulse pressure in this way, it is possible to keep the dispersion of the fibers in the stock raw material liquid optimum.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A twin wire former according to the present invention will be specifically described below based on the illustrated embodiments. First, the embodiment shown in FIGS. 1 and 2 will be described. This device is provided with opposing dewatering blade groups in the initial dewatering region of the conventional twin wire former shown in FIG. 7, and the position of one dewatering blade group can be changed to at least one of vertical and front and back. Has a big feature.

The flow of the stock raw material liquid will be described below. The stock raw material liquid 2 sandwiched between the paired wires 3 and 4 is
First of the dehydrating blade group body 6 called a forming board
Before landing on the dewatering blade 6a, it hits on the wire 3 called the bottom wire, and the pressure generated by the jet collision pressure and the tension of the wire 4 sandwiched between the two wires 3 and 4 that converge on the first dewatering blade 6a. By dehydration blade 6
b to both sides in the wire-free section, and wire 4 to the supporting surface.
Is dehydrated upwards through.

Next, the spacing between the two wires 3 and 4 is regulated by the dehydration blades 5a and 6c by the opposing dewatering blade groups 5 and 6 arranged in a plane within the two wire loops 3 and 4. . The regulation of the wire interval changes the dehydration pressure, which changes the dehydration amount. FIG. 3 shows an example of the relationship between the pushing amount of the dehydration blade 5a shown in FIG. 2 and the dehydration amount at the dehydration site. It is shown that the dehydration amount is increased by pushing the dehydration blade, and the ratio of the dehydration amount to the stock material liquid 2 ejected from the head box 1 can be significantly changed.

From the above, one of the opposing dewatering blade groups 5 and 6, that is, the dewatering blade group 5 installed in the loop of the top wire 4 in FIGS. 1 and 2 is moved up and down and back and forth by a drive device not shown. The structure is possible, and the amount of dehydration can be adjusted by this. In addition, the dehydration blade 5a in the dehydration blade group 5
Can be attached and removed freely, and the number of dehydrating blades 5a can be changed by inserting and removing the dehydrating blades.
This makes it possible to adjust the amount of dehydration from the stock raw material liquid and the shearing force applied to the stock raw material liquid.

With the above-mentioned constitution, the dispersion of the fibers in the stock raw material liquid can be adjusted so that the orientation thereof can be optimized. Although the drawing shows the case of installation in a horizontal twin wire former, it is clear that the present invention may be applied to a vertical twin wire former as shown in FIG. Further, as shown in FIG. 2, the first forming shoe 7 has an actuator A.
Is configured to be displaceable in the direction orthogonal to the wire, and the amount of dehydration from the stock raw material liquid can be adjusted here.

Next, the embodiment shown in FIGS. 4 and 5 will be described. 4 and 5, the same parts as those of the device shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof will be omitted. In the apparatus shown in FIGS. 4 and 5, the blade units 15 forming the blade unit group 15 are formed.
Each of a, 15b, and 15c is configured to be independently movable in the wire traveling direction by the motor 11, the screw rod 12, and the manual handle 13. 2 wire loops 3,
By moving the blade unit 15 facing the dehydration blade group 6 called a forming board disposed in the wire 4 and adjustable in the wire traveling direction as described above, the distance between the blades in the wire traveling direction is increased. L becomes wider or narrower. When the distance L between the blades is wide, the dehydration pressure is small, and as the distance L is narrow, the pressure increases.

Further, when only the blade unit 15a is moved, the distance between the blade unit 15b and the blade unit 15b is changed, so that the pitch of the pressure peak value can be changed. From the above, by adjusting the blade unit 15, the magnitude of pressure and the pitch of pressure peaks can be arbitrarily changed. The blade unit 15 is moved by rotating the screw rod 12 by the motor 11 and moving the blade units 15a, 15b, 15c, respectively. It should be noted that one blade unit 15 is equipped with one motor 11 and one screw rod 12,
It is a structure that can be moved independently. The blade unit 15 can also be moved by a manual handle 13 provided on the opposite side of the motor 11.

The present invention has been specifically described above based on the illustrated embodiments, but the present invention is not limited to these embodiments, and various configurations can be made within the scope of the present invention shown in the claims. It goes without saying that changes may be made. For example, in the embodiment shown in FIGS. 1 and 2, the blade groups facing each other are provided in the initial dewatering region of the twin wire former, and the position of the dewatering blade group 5 above it can be changed. The blade group 6 may be displaceable.

In the apparatus shown in FIGS. 1 and 2, the dewatering blades 5a in the dewatering blade group 5 are attachable / detachable so that the number thereof can be changed. The blades of the group 6 may be configured to be removable so that the number of the dehydrating blades 6 can be changed.

Furthermore, in the device shown in FIG. 1 and FIG.
Although the forming shoe 7 is configured to be displaceable in the direction orthogonal to the wire, the forming board 6 may be displaceable in the direction orthogonal to the wire instead of the first forming shoe 7.

[0027]

As described in detail above, according to the present invention, the pulsed dewatering pressure can be adjusted from the outside, and the dewatering amount, the shearing effect, and the pressure applied to the stock solution can be controlled. That is, the optimum dehydration amount and dehydration pulse pressure can be controlled with respect to the papermaking conditions such as basis weight and papermaking speed, and the wet paper web forming ability in the subsequent forming shoe can be maximized.

Further, the fibers uniformly dispersed in the head box can be optionally fixed as a paper layer.
In the case of the embodiment shown in FIGS. 1 and 2, the orientation of the fibers throughout the thickness direction of the paper as shown in FIG. 6, that is, the ratio of the number of fibers arranged in the direction perpendicular to the machine running direction (orientation ratio It has been clarified by the study of the present inventors that there is a great effect of making the above (1) uniform. From the above, it is possible to fabricate high-quality paper in which the fiber orientation (orientation degree) is uniform over the entire area of the paper layer and the dispersion is good under a wide range of papermaking conditions.

[Brief description of drawings]

FIG. 1 is an overall layout diagram of a twin wire former according to an embodiment of the present invention.

FIG. 2 is a detailed cross-sectional view of a main part of the first embodiment shown in FIG.

FIG. 3 is a graph showing changes in dehydration amount according to the examples shown in FIGS. 1 and 2.

FIG. 4 is an overall layout view of a twin wire former according to another embodiment of the present invention.

5 is a detailed cross-sectional view of the essential parts of the embodiment shown in FIG.

FIG. 6 is an explanatory diagram of a fiber orientation degree distribution in the thickness direction according to the embodiment shown in FIGS. 1 and 2.

7A and 7B are diagrams showing an example of a conventional twin wire former, FIG. 7A is an overall view thereof, and FIG.

FIG. 8 is an overall view of an example of a conventional hybrid former.

[Explanation of symbols]

1 Head Box 2 Stock Material Liquid 3 Bottom Wire 4 Top Wire 5 Counter Dehydration Blade Group 6 Forming Board 7 1st Forming Shoe 8 2nd Forming Shoe 9 Suction Box 11 Motor 12 Screw Rod 13 Manual Handle 15 Blade Unit Group 5a, 6a , 6b, 6c, 7a, 7b Dehydration blade 15a, 15b, 15c Blade unit

Claims (4)

[Claims] 1. A twin wire former for performing wet paper web formation by sandwiching a stock material jetted from a headbox with two dehydrating wires each forming a loop, and performing dehydration between the wires to form a wet paper web in one wire loop With a dewatering zone having a plurality of dewatering blades on the upstream side of,
A twin wire former for a paper machine, wherein a dewatering blade unit facing the dewatering zone is provided in the other wire loop so as to be movable up and down and at least one of front and back. 2. The twin wire former for a paper machine according to claim 1, wherein at least a part of the dewatering blade of the dewatering blade unit is attachable / detachable, and the number of blades in the dewatering blade unit is variable. . 3. The twin wire former for a paper machine according to claim 1, wherein a dehydration blade on a dehydration zone side facing the movable dehydration blade unit is configured to be movable in a direction orthogonal to the wire. 4. The twin wire for a paper machine according to claim 1, wherein the dewatering blade unit is formed of a plurality of blade units, and each of the units is independently movable in the wire traveling direction. Former.