JPH0428836B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a two-wire Fourdrinier paper machine in which two wires sandwiching a raw material can run on a surface other than the rolls and the suction box. The present invention relates to an applicable paper layer forming device.

(Prior Art) Figures 6 and 7 show examples of conventional double wire wire parts.
Curved shoe 1, dewatering blade (or deflector)
2, a curved or flat suction box 3, etc. The curved shoe 1 dehydrates the raw material (jet) coming out of the head box 4 by sandwiching it between the wires 5 and 6 using the pressure generated by the tension of the wire 5 along the curvature of the shoe 1, and improves fiber dispersion ability. There were few.

Further, the dewatering blade 2 dehydrates the raw material (jet) ejected from the head box 4 by pushing the required number of blades 2 into the wire loop and by pressure generated by the wire tension while sandwiching the raw material (jet) between the wires 7 and 8. However, the white water dehydrated on the outside is mainly removed by centrifugal force, and the white water on the inside is removed by the scraping action of the blade 2. Since this method applies the action intermittently, the fiber dispersion is better than curved surface shoe or roll winding methods, but the yield is poor. Although suction boxes have a large dehydration capacity, they do not have a fiber dispersion effect.

However, these methods have low fiber dispersion ability, so in actual operation it has not been possible to increase the concentration beyond the current level (the concentration of fiber alone is about 1% or less).

Dehydration occurs, which means that 100% of the raw material
This means instantaneously moving the water that occupies the vicinity, and also applying acceleration and, as a result, displacement to the fibers floating in this water. That is,
This means that the dispersion effect has no effect. The main reason for this is that the concentration of the raw material increases with dehydration, and concentrated fiber mats develop especially near the wire surface, rapidly impairing fluidity.

(Problems to be Solved by the Invention) The present invention solves the conventional problems such as poor yield and inability to increase concentration, and provides an effect while maintaining fluidity over a certain range. The present invention aims to provide a paper layer forming apparatus that can improve the dispersion effect.

(Means for Solving the Problems) For this reason, the present invention supports a running wire with a plurality of convex portions to give the wire a predetermined polygonal bend. The wire supporting device is provided with a wire support device having a recess formed to have a wedge space between the wire and this is used as a means for solving the problem.

(Function) Now, the pressure of the raw material sandwiched between the wires increases due to the wire tension near the convex part, and the white water is about to be dehydrated toward the wire, but the wedge space immediately behind it causes vacuum pressure in the opposite direction. receive. This vacuum pressure dehydrates the white water toward the wedge space, but as it approaches the convex part, the reversed wedge shape pushes the white water back toward the raw material side, and the white water oozes onto the wire again. Thereafter, each wedge space receives the same action.

(Embodiment) Below, embodiments of the present invention will be explained with reference to the drawings. Figs. 1 to 5 show embodiments of the present invention, and Figs. 1 to 3 show the formation devices A and B. Double wire fourdrinier paper machine (wire part)
Examples are shown in FIGS. 4 and 5. First, the wire support device of the formation forming device A shown in FIG.
Wires 13, 1 sandwiching the raw material 12 between 1a to 11d
It supports the inside of 4. In addition, these convex portions 11
The sections a to 11d have a concave cross-sectional shape so as to form spaces 15a, 15b, and 15c with wedge-shaped ends between the inner wire 14 and the inner wire 14. Note that 2 in FIGS. 4 and 5 is a dewatering blade, and 3 is a suction box.

Convex portions 11a to 11d that are contact portions with the wire
may be a point contact or a line contact, and the wedge space 15
If both ends of a, 15b, and 15c have acute angles, the intermediate surfaces may be parallel to the wire. Also wedge space 1
The angle formed by the wedge portions at both ends of 5a to 15c is 0 to 15c.
The angle is preferably about 10°, and the angles at both ends in one space may be the same, but it is better that the angle on the upstream side with respect to the flow of the raw material 12 is smaller than the angle on the downstream side.

Next, the formation forming device B shown in FIG. 2 is a combination of a member 16 equipped with a tip adjustment mechanism and a member 17 facing this with a required gap, and these members 16 and 17 are each made of a wire. It constitutes a support device. The uneven shape on the side facing the wires 13 and 14 is the same as in the case of device A, and the outer surface is cut off at an acute angle to prevent foreign matter from flying in.
The tip end 22 of 6 slightly expands the front end on the wire surface side between the members 16 and 17 to form a wedge space 19, which restricts the white water coming out on the wire 13 surface side and connects the internal wedge space with the outside air. Perform a cutoff. The gap between the opposing part of the member 17 can be finely adjusted by the adjusting device 20 (this is not absolutely necessary and can be covered with precision). The tip 18 of the member 17 is a guide for the wires 13, 14 and the raw material 12 that advance to the formation forming section, and the sharp tip scrapes off foreign matter and dehydrated white water outside the wire.

In addition, the distance between the members 16 and 17, which serve as passageways for the raw material 12 and the wires 13, 14, is in principle parallel, and this distance is based on the thickness of the wires 13, 14 and the raw material 12 at this position under the papermaking conditions as a reference value. , set by taking driving experience into consideration. Also, although the shape of the passageway is shown as a straight line in Figure 2, it may have a curvature. Furthermore, FIG. 3 shows the configuration shown in FIG. 2 in which the members are shifted back and forth while keeping the gaps between the members constant.

Next, to explain the operation of the embodiment configured as above, first, in the embodiment of FIG. 1, the raw material 12 sandwiched between the wires 13 and 14 is
The pressure rises due to the wire tension near the top of point a, and the white water is about to be dehydrated toward the wire 13, but the wedge space 15a immediately behind increases the vacuum pressure in the opposite direction (dehydration force). This vacuum pressure dehydrates the white water toward the wedge space, but as it approaches the convex portion 11b, the reversed wedge shape pushes the white water back toward the raw material side, and the white water oozes onto the wire 13 again. The same effect is applied to each wedge space below. This effect becomes stronger as the wedge space fills up.

In the case of conventional various wire parts, once dehydrated white water is not returned to the raw material side,
Each time the raw material is dehydrated, the raw material becomes concentrated and a fiber mat develops from the dehydrated wire side, so the movement of water, which makes up the majority of the raw material, also decreases, reducing the dispersion effect, and in some cases even breaking the fiber mat. Sometimes it happens.

On the other hand, in the case of the device of the present invention, the vacuum pressure in the wedge space acts on the white water flowing toward the wire 13 side.
The outflow of white water while passing over this device can be almost suppressed, and there is almost no change (improvement) in the average raw material concentration. In addition, the dehydration (vacuum) action and the pushing action of white water, which are applied transiently the required number of times, involve shaking of the water under this raw material concentration, but since maintaining the concentration means maintaining fluidity, this shaking of the water The fiber dispersion effect due to the movement is cumulative as it passes over the device, creating a significant dispersion effect.

Next, to explain the operation of the embodiment shown in FIG. 2, the device A gives a dispersion effect from one side, whereas in this case, the same effect is applied from both sides.
Furthermore, it is intended to provide homogenization and symmetry in the thickness direction of the raw material 12.

The function of this device is basically the same as that of device A, but by making the two members 16 and 17 face each other to restrict the flow of white water, the wire 1
It has the effect of changing the speed of the raw material sandwiched between 3 and 14 in the running direction. This is the second
In the configuration shown in the figure, as can be easily understood by considering the flow of only the fluid without the wires 13 and 14, the fluid containing the raw material and white water passes through the constriction portion 21 formed by the convex portions of the members 16 and 17. When passing through this point, the flow rate increases, and as the flow path widens, the flow rate decreases. However, since the wire advances at a constant speed, there is relative movement between the wire, fibers and other solids in the raw material, and moisture, creating a dispersion effect.

In this way, the configuration of device B shown in Fig. 2 produces an accumulation of dispersion effect due to the flow in the thickness direction of the raw material, which is a feature of device A, and an accumulation of dispersion effect due to the movement of the raw material in the direction of movement of the raw material, resulting in a fiber dispersion effect. It is intended to improve

Next, the embodiment shown in FIG. 3 will be described. In this embodiment, the members 16 and 17 of the apparatus B shown in FIG. 2 are arranged offset in the flow direction of the raw material. In this usage, the dispersion effect due to the relative flow in the raw material running direction is lost, but by applying the action of device A from both sides of the raw material, the swinging action in the thickness direction of the raw material can be doubled. This is intended to increase the dispersion effect. Furthermore, in this method, the pushing force for the running of the raw material and the wire can be freely and largely changed within the range permitted by the wedge space, and the applied force can be easily adjusted over a wide range.

(Effects of the Invention) Since the present invention is constructed as described in detail above, the formation dispersion (fiber dispersion) effect is greatly improved over the conventional apparatus. In addition, the white water in the wedge space acts as a lubricant for the wire and the protrusions, extending the life of the wire and reducing driving power.

[Brief explanation of drawings]

1, 2, and 3 are side sectional views of a paper layer forming apparatus showing an embodiment of the present invention, and FIGS. 4 and 5 show the apparatus shown in FIGS. 1 and 2, respectively. Side view of the double wire Fourdrinier paper machine, Figures 6 and 7
Each figure is a side view showing an example of a conventional double wire type wire part. Explanation of main parts of the figure, 10... Wire support device, 11a to 11d... Convex portion, 12... Raw material, 1
3, 14... Wire, 15a-15c... Wedge space, 16, 17... Member (wire support device).

Claims (1)

[Claims] 1. A running wire is supported by a plurality of convex parts to give the wire a predetermined polygonal bend, and between the convex parts there is a concave part formed so that both ends have a wedge space with the wire. A paper layer forming device comprising a wire support device.