JP3328618B2 - Slurry supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slurry supply device. More specifically, the present invention relates to a slurry supply device capable of discharging a slurry at a uniform flow rate over the entire width of a slurry discharge port.

[0002]

2. Description of the Related Art Conventionally, fiber-reinforced cement boards have been widely used as exterior materials such as building exterior walls and roofing materials.
For example, it is produced by a papermaking method as shown in the schematic diagram of FIG. In the papermaking method shown in FIG. 4, for example, cement and fiber are used as main raw materials, and a solid composition having a solid content of 5 obtained by dispersing a cement composition in which a filler is appropriately added and mixed in water is used.
A slurry having a relatively low concentration of about 30% is formed into an endless continuous body from a slurry supply device (1), and is suspended on a driving roll (2) and a driven roll (3). The sheet is supplied at a predetermined papermaking width onto a water-permeable sheet (4) having a water permeability such as felt moving in the direction, and is turned into a green sheet. The green sheet is vacuum-suctioned from below and dehydrated to produce a raw plate. The vacuum-solid-liquid separator (5) is provided with, for example, a suction box (51) to support the water-permeable sheet (4) from its back surface and secure a dewatering space.

[0003] Various types of slurry supply devices (1) have been proposed for use in such a papermaking method, and one of them is, for example, a slurry supply device as shown in FIGS. is there. The slurry supply device shown in FIGS. 5 and 6 is connected to the slurry supply pipe (6) and the end of the slurry supply pipe (6), communicates with the slurry supply pipe (6), and has a horizontal width extending upward. And a slurry discharge port (8) provided at the upper end of the slurry diffusion section (7) and having a width equal to the papermaking width. The slurry adjusted to a predetermined mixing ratio and solid content concentration is gradually spread laterally in the slurry diffusion section (7) through the slurry supply pipe (6), is expanded to the papermaking width, and the slurry discharge port ( 8) to the water-permeable sheet (4) shown in FIG.

[0004]

However, in the above-mentioned slurry supply apparatus, as shown in FIG. 6, the terminal end (61) of the slurry supply pipe (6) is connected to the lower end of the slurry diffusion section (7). Therefore, the slurry flowing from the slurry supply pipe (6) into the slurry diffusion section (7) collides with the wall (71) of the slurry diffusion section (7) and changes its flow upward. Creates a pressure field,
As a result, a distribution occurs in the flow velocity of the slurry in the slurry diffusion portion (7) in which the lateral width gradually increases upward. Therefore, the flow rate of the slurry discharged from the slurry discharge port (8) toward the water-permeable sheet (4) shown in FIG. 4 is high at both ends of the water-permeable sheet (4) and slow at the center. Such a flow velocity distribution of the slurry is reflected in the amount of slurry supplied to the water permeable sheet (4), and the slurry cannot be supplied to the water permeable sheet (4) with a uniform thickness. As a result, the thickness of the fiber reinforced cement board as the final product varies.

[0005] The invention of this application has been made in view of the above circumstances, and solves the above-mentioned disadvantages of the slurry supply apparatus proposed so far, and makes the slurry uniform over the entire width of the slurry discharge port. It is an object of the present invention to provide a slurry supply device capable of discharging at a high flow rate.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by providing a slurry supply pipe, which is connected to the end of the slurry supply pipe and communicates with the slurry supply pipe, and A slurry diffusion part whose width gradually increases,
A slurry supply device provided at the upper end of the slurry diffusion unit and having a slurry discharge port having a width equal to the papermaking width, wherein the end of the slurry supply pipe is the shortest from the lower end of the slurry diffusion unit to the upper end. A slurry supply device (Claim 1) is provided which is connected 3 to 15% above the length.

In the invention of this application, the slurry diffusion portion has an inverted triangular front shape (Claim 2), and the slurry diffusion portion has a semicircular front shape (Claim 3). It is provided as a preferred embodiment.
Hereinafter, the slurry supply apparatus of the present invention will be described in more detail with reference to the drawings.

[0008]

1 and 2 are a perspective view and a side view, respectively, showing a main part of an embodiment of a slurry supply apparatus according to the present invention. For example, as shown in FIGS. 1 and 2, the slurry supply device of the invention of the present application includes a slurry supply pipe (6) and a slurry supply device similar to the conventional slurry supply devices shown in FIGS. A slurry diffusion section (7) connected to the end of the pipe (6) and communicating with the slurry supply pipe (6), and having a width gradually increasing upward; and provided at an upper end of the slurry diffusion section (7); A slurry discharge port (8) having a width equal to the papermaking width.

In the slurry supply apparatus of the present invention, the end (61) of the slurry supply pipe (6) has a minimum length (d) of 3 from the lower end to the upper end of the slurry diffusion section (7). It is connected to the position (x) which is 〜15% higher. As described above, the connection position of the end portion (61) of the slurry supply pipe (6) is not the lower end of the slurry diffusion portion (7) but the shortest length (d) from the lower end to the upper end of the slurry diffusion portion (7). ), The slurry flowing from the slurry supply pipe (6) into the slurry diffusion section (7) collides with the wall (71) of the slurry diffusion section (7). Although it sneaks, it is possible to flow also downward from the slurry supply pipe (6). For this reason,
The pressure field generated when the slurry collides with the wall (71) of the slurry diffusion part (7) is dispersed, and the pressure distribution in the slurry diffusion part (7) is suppressed. As a result, the flow velocity distribution of the slurry in the slurry diffusion section (7) is reduced, and the flow velocity of the slurry discharged from the slurry discharge port (8) is
It becomes uniform or almost uniform over the entire width of the slurry discharge port (8). Therefore, the thickness of the slurry supplied on the water-permeable sheet (4) shown in FIG.
The thickness of the fiber reinforced cement board as the final product does not vary and becomes uniform.

As described above, the slurry diffusion portion (7) has a configuration in which the width is gradually increased upward, and thus generally has an inverted triangular front shape as shown in FIG. However, the front shape of the slurry diffusion section (7) is not particularly limited to an inverted triangle, but may be, for example, a semicircle as shown in FIG. When the front shape of the slurry diffusion portion (7) is semicircular, the slurry diffusion portion (7) has a slurry supply pipe as compared with the case of the inverted triangular front shape shown in FIG. Also at the connection part of the terminal part (61) of (6), the terminal part (6)
Therefore, the flow which collides with the wall portion (71) of the slurry diffusion portion (7) and deflects laterally can be sufficiently and gently spread laterally. There is an advantage that the flow rate of the slurry discharged from 8) becomes more uniform.

Further, in the slurry supply apparatus of the invention of this application, as shown in FIG.
The slurry supply pipe (6) can be inclined at an angle (θ ₁ ) and connected to the terminal end (61), and the angle (θ ₁ ) can be, for example, 100 to 135 °. At this time, the angle (θ ₂ ) of the slurry diffusion portion (7) with respect to the vertical line (y) can be set to 10 to 45 °. By arranging the slurry diffusion section (7) in this manner, in the slurry supply device of the invention of the present application, when the slurry flows from the slurry supply pipe (6) to the slurry diffusion section (7), the slurry diffusion section ( 7) The collision with the wall portion (71) can be reduced, which is effective in making the flow velocity of the slurry uniform.

[0012]

EXAMPLES In fact, FIG. 1, respectively indicated slurry dispenser 3 (however, slurry spreading section (7), a slurry supply pipe (connection angle with respect to 6) (theta ₁₎ and vertical line (y)
Angle (θ ₂ ) is set to 120 ° and 30 ° respectively)
In the slurry supply apparatuses of the first and second embodiments and the first and second embodiments, the conventional type in which the end portion (61) of the slurry supply pipe (6) is connected to the lower end of the slurry diffusion section (7). Using the slurry supply apparatus (Comparative Example 1 and Comparative Example 2), a raw plate was produced according to the papermaking method shown in FIG.
Then, the flow velocity difference in the width of the slurry discharged from the slurry discharge port (8) and the thickness difference of the green plate to be produced were measured. The results are as shown in Table 1 below.

[0013]

[Table 1]

As is apparent from Table 1, in the slurry supply apparatus of the present invention, the difference in flow velocity in the width of the slurry discharged from the slurry discharge port (8) is sufficiently small, and the thickness of the raw plate is substantially uniform. Becomes On the other hand, in any of the conventional slurry supply apparatuses, the flow velocity difference was larger than that of the slurry supply apparatus of the present invention, and the unacceptable thickness variation occurred in the raw plate.

Comparing the first embodiment with the second embodiment, the slurry supply device of the second embodiment, in which the front surface of the slurry diffusion section (7) has a semicircular shape, is discharged from the slurry discharge port (8). The flow velocity difference in the width of the slurry is smaller,
It is confirmed that the thickness difference of the raw plate is further reduced. Of course,
The invention of this application is not limited by the above embodiments and examples. It goes without saying that various modes are possible for details such as the shape and size of the slurry supply pipe, the slurry diffusion section, and the slurry discharge port.

[0016]

As described in detail above, according to the invention of this application, the slurry can be discharged at a uniform flow rate over the entire width of the slurry discharge port, and the thickness of the slurry supplied on the water-permeable sheet is uniform. Becomes The fiber reinforced cement board, which is the final product, has no variation in thickness,
Good quality product.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of a slurry supply device of the present invention.

FIG. 2 is a side view of the slurry supply device shown in FIG.

FIG. 3 is a perspective view of an essential part showing another embodiment of the slurry supply device of the present invention.

FIG. 4 is a schematic view showing production of a fiber-reinforced cement board by papermaking.

FIG. 5 is a perspective view illustrating a slurry supply device before the invention of this application.

FIG. 6 is a perspective view of a main part of the slurry supply device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slurry supply apparatus 2 Drive roll 3 Follower roll 4 Water-permeable sheet 5 Vacuum solid-liquid separation apparatus 51 Suction box 6 Slurry supply pipe 61 Termination part 7 Slurry diffusion part 71 Wall part 8 Slurry discharge port

──────────────────────────────────────────────────の Continuing from the front page Examiner Shigehiro Toyonaga (56) Reference JP-A-59-157394 (JP, A) JP-A 64-51697 (JP, U) JP-A 4-123296 (JP, U) Table Hei 8-503265 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B01J 4/00 D21F 1/00-13/12 B28B 1/52 B28B 13/00

Claims (3)

(57) [Claims] 1. A slurry supply pipe, a slurry diffusion section connected to the end of the slurry supply pipe and communicating with the slurry supply pipe, and having a width gradually increasing upward and provided at an upper end of the slurry diffusion section. A slurry supply device having a slurry discharge port having a lateral width equal to the papermaking width, wherein a terminal end of the slurry supply pipe is connected to the lower end of the slurry diffusion portion and 3 to 15% of a shortest length from the upper end to the upper end. A slurry supply apparatus characterized in that the slurry is supplied. 2. The slurry supply device according to claim 1, wherein the slurry diffusion section has an inverted triangular front shape. 3. The slurry supply apparatus according to claim 1, wherein the slurry diffusion section has a semicircular front shape.