JPS6231112B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a sectional view of a slicing chamber 2 for spouting paper stock liquid from the opening of a conventional slicing lip 1. As shown in FIG. From the pre-slicing chamber 3, the paper stock liquid passes through a plurality of rows of holes 5 in the perforated plate 4 and enters the slicing chamber 2, which is converged towards the slicing opening by means of the top plate 6 and the bottom plate 7. The interior of the slicing chamber is partitioned by a flow restriction element 8 to form a plurality of flow restriction channels 9. Due to the hydrodynamic effects of the raw material flow, the flow restraining elements 8 are kept in a spaced apart position.

However, the conventional device shown in FIG. 1 has the following drawbacks. In other words, the current suppressing element 8 has the advantage that the large vortex on the upstream side rapidly becomes smaller as it goes downstream, and a stable paper stock liquid can be ejected from the slice opening in the width direction, but the dispersion of the fibers is not sufficient. , paper with small flocs was the finished product. Furthermore, in the case of long fibers, the fibers tend to line up in the machine direction, and the tensile strength of the paper differs greatly between the length and width.

Conventional fiber dispersion has been carried out by the stirring effect caused by passing the paper stock liquid through a perforated plate or the like. The large vortex created by stirring is
Large flocs are produced, and small vortices produce small flocs.

On the other hand, if you change the cross-sectional area of the channel through which the paper stock liquid flows and apply acceleration and deceleration to the paper stock liquid, the force that stretches the fibers in the flow direction in the acceleration region and the thickness direction and width in the deceleration region The research conducted by the present inventors has revealed that a paper stock liquid with good fiber dispersion can be obtained by applying a stretching force in the same direction.

The present invention prevents the total volume of the slicing chamber from changing throughout the flow direction of the slicing chamber during operation.
and one or more flexible bodies that reciprocate in an undulating manner are disposed opposite to the inner surface of the slicing chamber, and the flexible bodies are reciprocated in an undulating manner toward the center of the slicing chamber in the flow direction of the slicing chamber. It is an object of the present invention to provide a paper machine headbox in which the cross-sectional area of the slice channel is increased or decreased to cause acceleration and deceleration of the flow.

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is a sectional view of a slicing chamber 11 for spouting paper stock liquid from an opening of a slicing lip 10 showing an embodiment of the present invention. The paper raw material liquid is
From the preslicing chamber 13 it passes through a plurality of holes 15 in the perforated plate 14 and enters the slicing chamber 11, which converges towards the slicing opening by way of a top plate 16 and a bottom plate 17.

The top plate 16 can be rotated about a fulcrum 18 by operating a jack rod (not shown),
The distance between the slice lip tip 10b and the bottom plate 17 can be adjusted. The slice lip 10 has a low-rigidity neck portion 10c shown in Japanese Patent Application No. 55-28722 between an attachment portion 10a that is fixed to the top plate 16 and a tip portion 10b, and a jack rod (not shown) attached to the tip portion can be operated. As a result, the distance between the tip end 10b of the slice lip and the bottom plate 17 is widened,
Alternatively, the width direction basis weight profile can be finely adjusted by bending the lip so as to narrow it, changing the lip opening degree, or changing the width direction opening degree.

Reference numeral 19 designates a plurality of flexible bodies that can be passed through in the width direction, and are designed to increase or decrease the cross-sectional area of the slice channel by means of an operating rod 20 that is reciprocated by a drive device (not shown). At this time, the top part 16, the bottom plate 17, the plurality of flexible bodies 19, the perforated plate 1
4. The total volume of the slicing chamber 11 surrounded by the slicing lip 10, the slicing lip opening, and a side plate (not shown) is not changed by the movement of the flexible body 19. When the volume inside the slicing chamber 11 changes over time, pressure changes and the jet speed changes, which causes uneven paper thickness in the flow direction of the sheet formed on the wire, and also causes paper breakage. becomes. Therefore, the volume within the slicing chamber 11 must remain constant as a whole. Note that the stroke of the operating rod 20 can be changed.

Further, the movement of the plurality of flexible bodies 19 passing through in the width direction can be controlled by a driving device, and can be moved in the same phase in the width direction, or can be driven in a phase shifted manner in the width direction. In addition, the movements of the flexible bodies 19 arranged in the flow direction of the paper stock liquid are coupled so that the line connecting the central portions 19a of the flexible bodies 19 in the flow direction shown by the broken line A in FIG. 2 forms a waveform. It is also possible to make the shape of the waveform progress in the upstream direction in time.

A plurality of small chambers 21 on the back side of the flexible body 19 are filled with a liquid having the same pressure as the paper stock liquid flowing through the slicing chamber 11, and are connected to other small chambers through a plurality of communication pipes 22.

Next, the effect will be explained. By moving the flexible body 19 and changing the cross-sectional area of the flow path, the flow of paper stock liquid flowing therethrough is accelerated. When the flocs are in the acceleration region, the upstream flow velocity is low and the downstream flow velocity is high, so the flocs are torn off and dispersed. In the deceleration region, the flow velocity is reversed, so the flocs are stretched in a direction perpendicular to the average direction of movement, that is, in the thickness direction and width direction. By repeating this process, the floc becomes finely divided and the fibers are uniformly dispersed in the paper raw material liquid.

Furthermore, by changing the cross-sectional area of the flow path as described above, the flow of the paper stock liquid flowing through it is accelerated and decelerated, and the flocs in the paper stock liquid receive force from the flow of water and accelerate and decelerate. However, since the fiber density in the center of the floc is high and the density is low in the peripheral area, the force that the fibers receive from the water flow differs depending on the area. Because the fibers overlap in the center, the force received from water during acceleration and deceleration is weak, while it is strong in the periphery.

Therefore, when the floc is in the acceleration region, the periphery expands in the direction of flow, while when it is in the deceleration region, the periphery expands in the upstream direction of the flow. By repeating this process, the flocs will be dispersed from the periphery, and the fibers will be uniformly dispersed in the paper stock liquid. If there is a difference in density or a weak bonding force in the center of the flock, division is performed from there for the reasons mentioned above.

In the acceleration region, the fibers are oriented in the average traveling direction, but in the deceleration region, the fibers are pushed from behind, so the directions become scattered. Therefore, the dispersed fibers have no direction, and the undispersed flocs also become oriented randomly unless they are spherical due to fluid resistance. Therefore, a dispersion force acting at a different angle will act on the undispersed flocs. When the flexible body 19 is moved in the direction of the slicing chamber 11 by the operating rod 20, liquid from other chambers passes through the communication pipe 22 by the amount that the volume of the chamber 21 on the back side of the flexible body 19 has increased. Because of the inflow, the overall volume of the chambers connected by the communication tube 22 becomes constant. Therefore, the volume of the slicing chamber 11 is always constant.

FIG. 3 shows an embodiment different from that shown in FIG. 2, in which a portion of the slicing chamber 23 is partitioned off by a current suppression element 24 to form flow suppression channels 25, 25. Also, the perforated plate 26
The vortices generated in the paper stock liquid when it passes through the rows of holes 27 rapidly become smaller as it flows through the suppression flow path 25, so the dispersion of the fibers is less likely to be hindered by the vortices. Since the fibers are uniformly dispersed in the paper stock liquid by the movement of the plurality of flexible bodies 19, the paper made by dewatering this on a wire has good fiber dispersion.

The plurality of flexible bodies 19 may be threaded in the width direction, or may be circular. Furthermore, it is not necessary to control the movements of all of the plurality of flexible bodies 19 so that the volume of the slice chamber is always constant; for example, half of the operating rods 20 are controlled, and the other half of the operating rods 20 are controlled. The flexible body 19 may be allowed to move freely as the liquid in the small chamber moves. Furthermore, the plurality of flexible bodies can be driven and controlled using electromagnetic force at high frequency.

The embodiment shown in FIG.
9 is a sectional view of FIG. The paper raw material liquid is in the front slicing chamber 3.
8, a slicing chamber passes through a plurality of holes 40 in the perforated plate 39 and converges toward a slicing opening formed by the planar upper flexible body 30, lower flexible body 31, and a side plate (not shown). Enter 29. Further, the top plate 34 can be rotated about a fulcrum 41 by operating a jack rod (not shown), so that the distance between the slice lip tip 28b and the lower lip 42 can be adjusted.

Further, the upper flexible body 30 and the lower flexible body 31 are connected to an operating rod 33 through a pin portion 32, and the cross-sectional area of the slice flow path is controlled by the operating rod 33, which is reciprocated by a drive device (not shown). increase or decrease. By making the top chamber 35 and the bottom chamber 37 sealed, the total volume of the slicing chamber 29 does not change due to the movement of the flexible body.

The upper flexible body 30 and the lower flexible body 31 can be controlled by a drive device and can be moved in the same phase in the width direction, or can be driven in a phase shifted manner in the width direction. Further, the waveform shapes of the flexible bodies 30 and 31 may be made to proceed in the upstream direction of the flow, and the temporal change in the cross-sectional area of the flow path may be made to proceed in the opposite direction to the direction of flow.

Furthermore, the top chamber 3 between the upper flexible body 30 and the top plate 34
5, and a bottom chamber 3 between the lower flexible body 31 and the bottom plate 36
7 is filled with a liquid having the same pressure as the paper stock liquid flowing through the slicing chamber 29, and has a sealed structure. As described above, when the flexible bodies 30 and 31 are used, the cross-sectional area of the flow path can be changed greatly and freely, so that the optimal shape can be obtained to uniformly disperse the fibers in the paper stock liquid. Can be adjusted.

FIG. 5 shows still another embodiment, and is a sectional view of a slicing chamber 44 for spouting paper stock liquid from the opening of the slicing lip 43. The paper stock liquid enters the slicing chamber 44 from the pre-slicing chamber 45 through multiple rows of holes 47 in the perforated plate 46 and into the slicing opening formed by the top plate 48, the bottom plate 49, and the side plates (not shown).

The inside of the slicing chamber 44 is partitioned by a current suppressing element 51,
Suppressing flow paths 52, 52 are formed. Due to the hydrodynamic effects of the raw material flow, the flow restricting elements 51 are kept in a spaced apart position. Further, the top plate 48 can be rotated about a fulcrum 53 by operating a jack rod (not shown), so that the distance between the slice lip tip 43b and the bottom plate 49 can be adjusted.

A plurality of rows of flexible bodies 50 are attached to the top plate 48 and the bottom plate 49, and a pressure cylinder 54 applies pressure higher or lower than the liquid pressure of the paper stock liquid to the inside 50a of the flexible bodies 50. By continuously changing the pressure and moving the liquid contact portion 50b of the flexible body in and out of the slicing chamber 44, the cross-sectional area of the slicing channel is increased or decreased.

At this time, in order to prevent the volume of the slicing chamber 44 (total volume filled with paper stock liquid from the perforated plate to the slicing outlet) from changing due to the movement of the plurality of flexible bodies, the pressurizing cylinder 54 is operated by a piston. One or more flexible bodies are piped into a cylinder chamber 56 partitioned by a cylinder chamber 55, and the same number of flexible bodies are piped into a cylinder chamber 57.

Since the present invention is configured as described above in detail, by applying acceleration and deceleration to the paper stock liquid flowing through the slicing chamber, the fibers can be uniformly dispersed in the paper stock liquid, and the fibers can be dispersed in the paper stock liquid. Paper made by dehydration above has good fiber dispersion. The larger the acceleration and deceleration applied to the paper stock liquid, the better the fiber dispersion will be. However, if the acceleration and deceleration are too large, vortices will be generated in the flow of the paper stock liquid, which is undesirable and causes flocs. By adjusting the amount, the most preferable state of fiber dispersion can be achieved.

In addition, the fibers in the paper stock liquid are oriented in the average direction of flow in the acceleration region, but in the deceleration region, the fibers are pushed from behind, so their directions are scattered, and the fibers are oriented in the width direction or thickness direction. Paper with strong paper strength in the direction and thickness direction can be obtained. Furthermore, since the fibers are well dispersed, paper can be made even if the concentration of the paper stock liquid is increased.
This improves the fiber yield, reduces water consumption, reduces pump capacity and running costs, and makes the machine for dewatering and papermaking the paper stock liquid more compact.

In addition, when paper is made with a high density, the paper strength in the thickness direction of the paper improves, and the fibers break apart in the deceleration region mentioned above, which overlaps with the effect of increasing the paper strength in the thickness direction, which is a problem in offset printing. Improves paper strength and reduces blister problems.

Furthermore, by driving the individual flexible bodies in conjunction with each other under the condition that the volume of the slicing chamber is constant, the motion of each flexible body gives acceleration/deceleration to the paper stock liquid, dispersing the fibers, and at the same time improving the overall By changing the cross-sectional area of the flow path over time, it is possible to accelerate and decelerate the entire paper stock liquid flowing through it up to the center of the flow, making it possible to obtain a paper stock liquid with fibers dispersed all the way to the center. .

Note that if the temporal change in the flow path cross-sectional area is made to proceed in the opposite direction to the traveling direction of the paper stock liquid, the paper stock liquid will undergo numerous accelerations and changes while flowing through the flow path in the head box of the same length. A reduction in speed is applied, and a paper with better fiber dispersion is obtained accordingly.

The paper strength in the width direction of the paper is weaker than in the machine direction, but if you want to improve the paper strength in the width direction,
By changing the amount of deflection of the flexible body in the width direction, by installing a circular flexible body, and applying acceleration and deceleration to the paper raw material liquid in the width direction, increasing the chances of the fibers lining up in the width direction, the width can be increased. Paper with directional paper strength can be obtained. By creating multiple chambers on the back side of the flexible body and connecting them to each other, even if there is a slight error in controlling the operating rod,
The volume of the slicing chamber is held constant, resulting in a constant rate of jet ejection from the slicing opening.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a conventional paper machine headbox, and FIGS. 2, 3, 4, and 5 are side sectional views of a paper machine headbox each showing an embodiment of the present invention. Explanation of main parts of the figure 10... Slice lip,
11... Slice chamber, 16... Top plate, 17... Bottom plate, 1
9... Flexible body, 20... Operation rod, 21... Small chamber, 22...
Communication pipe.

Claims (1)

[Claims] 1. One or more flexible bodies are installed opposite to the inner surface of the slicing chamber so that the total volume of the slicing chamber does not fluctuate in the flow direction of the slicing chamber during operation, and that reciprocates in an undulating manner. A paper machine characterized in that a flexible body is reciprocated in a waving manner toward the center of the slicing chamber in the flow direction of the slicing chamber to increase or decrease the cross-sectional area of the slicing channel, thereby causing acceleration and deceleration of the flow. Headbox.