JPH09248810A - Dehydration method in manufacturing inorganic board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accelerate dehydration through compression, and prevent the adhesion of material to rolls by compressing reverse surface of a green sheet by means of compression rolls sheathed with an elastic body layer in its surface in a manner interposing a release film between the compression rolls and the green sheet. SOLUTION: When a green sheet 1 is forwarded, it is forwarded as being undergone dehydration through vacuum suction from the suction box 10. As the green sheet 1 moves to the predetermined position in its front, a release film 4 is superimposed on the green sheet 1, and as it further moves in its front, the green sheet 1 is compressed through compression of the compression rolls 3. When compressed by means of the compression rolls 3, since an elastic body layer 2 exists on the surface of each compression roll 3, the green sheet 1 is compressed over the wide contact area thereof through an elastic deformation of the elastic body layer 2, thereby effectively compressing the green sheet 1, and thus accelerating dehydration through compression.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a building exterior material,
Alternatively, the present invention relates to a method used for dehydrating a green sheet produced by making a slurry when manufacturing an inorganic plate used as an interior material.

[0002]

2. Description of the Related Art Generally, when dehydrating a green sheet made of a slurry, the green sheet sent on a filter cloth is vacuum-sucked from the lower surface for suction dehydration. If you do, there is a limit to dehydration. In order to further improve the dehydration, it is also practiced to suck and dehydrate from the lower surface side of the green sheet and squeeze from the upper surface side of the green sheet with a pressure roll.

[0003]

When the roll squeezing is used in addition to the suction dehydration by vacuum suction as described above, the dehydration is accelerated to some extent, but when the pressure roll is squeezed, the pressure roll is Due to the point contact, it is difficult to apply pressure to the green sheet and effective compression is not performed.In addition, the pressure roll locally contacts the green sheet, which may cause a bank to crack and the product surface to crack. Is likely to occur. Further, there is a problem that the material adheres to the pressure roll and maintenance is difficult.

The present invention has been made in view of the above-mentioned points, and promotes dehydration by squeezing, prevents material from adhering to a roll, and further enhances the dehydration effect by combined use with dehydration by vacuum suction. Is an issue.

[0005]

In order to solve the above problems, the dehydration method in the production of the inorganic plate of the present invention is a method of dehydrating while continuously feeding the green sheet 1 in which the slurry is made into paper. One side of the green sheet 1 is sucked and dehydrated from one side of the green sheet 1, and the other side of the green sheet 1 is covered with the release layer 4 between the pressure roller 3 and the green sheet 1. It is characterized by being squeezed through. Since the elastic layer 2 is present on the surface of the pressure roll 3 when the pressure is applied by the pressure roll 3, the elastic layer 2 can be elastically deformed to press the green sheet 1 with a wide contact area. 1 can be effectively squeezed to accelerate dehydration by squeezing. Further, by applying pressure with the pressure roll 3 through the release film 4,
The material does not adhere to the pressure roll 3 from the green sheet 1 side, and the maintenance of the pressure roll 3 can be facilitated. Further, when the green sheet 1 is squeezed by the pressure roll 3, it can be pressed with a wide contact area and can be dehydrated by covering the side opposite to the side to be sucked and dewatered by the release film 4, so that dehydration by vacuum suction and dehydration by squeezing are combined The dehydration effect can be further enhanced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows the entire apparatus for papermaking. A filter cloth 6 such as felt is laid between the front and rear transport rolls 5, and the filter cloth 6 is fed in a direction indicated by an arrow A at a predetermined feeding speed. A hopper 8 for supplying a slurry 7 of an inorganic material containing fibers is arranged above the rear portion of the filter cloth 6 which is opposite to the feed direction, and below the hopper 8 is a slurry 7 in the feed direction of the filter cloth 6. There is provided a slurry outlet 9 for discharging Filter cloth 6
A suction box 10 is arranged on the lower surface side of the suction box 10 so as to straddle between the front and rear transport rolls 5, and a high vacuum can be suctioned from the suction box 10. A plurality of pressure rolls 3 are provided on the front of the filter cloth 6.
Are arranged in parallel. This pressure roll 3 is shown in FIG.
As shown in, the elastic layer 2 is integrally formed on the outer peripheral surface of the metal roll body 11. The elastic layer 2 is formed of thick fabric, sponge, or the like. The release film 4 is supplied between the pressure roll 3 and the filter cloth 6. This release film 4
Has an endless belt shape and is wound around a plurality of guide rolls 12. The release film 4 is formed of a polyethylene film, a polypropylene film, a fluorine resin film, or the like.

When the filter cloth 6 is fed in the direction of arrow A and the slurry 7 is discharged from the slurry outlet 9 of the hopper 8,
The slurry 7 is formed into paper, the green sheet 1 is continuously formed, and the green sheet 1 is sent. When the green sheet 1 is sent, it is sent while being dehydrated by vacuum suction from the suction box 10. When the green sheet 1 moves to a predetermined position in front, the release film 4 is superposed on the green sheet 1, and when it moves further forward, it is pressed by the pressure roll 3 and the green sheet 1 is squeezed. . Since the elastic layer 2 is present on the surface of the pressure roll 3 when compressed by the pressure roll 3,
As shown in (b), the elastic layer 2 can be elastically deformed to press the green sheet 1 over a wide contact area, and the green sheet 1 can be effectively squeezed to accelerate dehydration by squeezing. Further, by pressing with the pressure roll 3 via the release film 4, the material does not adhere to the pressure roll 3 from the green sheet 1 side, and the maintenance of the pressure roll 3 can be facilitated. Further, when the green sheet 1 is squeezed by the pressure roll 3, it can be pressed with a wide contact area and can be dehydrated by covering the side opposite to the side to be sucked and dewatered by the release film 4, so that dehydration by vacuum suction and dehydration by squeezing are combined The dehydration effect can be further enhanced. Furthermore, when suction dehydration is performed without the release film 4, the green sheet 1 is likely to have a nest, but in the case of the present invention, the nest can be prevented.

[0008] Next, the performance in the case of dewatering with the apparatus of the present invention as shown in FIG. 1 and the performance in the case of dewatering with the apparatus of the comparative example of FIG. 3 will be compared. In the apparatus of the present invention, as the pressure roll 3, a metal roll body 11 wound with a fabric having a thickness of 2 mm was used. The device of the comparative example eliminates the release film 4, the guide roll 12 and the pressure roll 3 of the device of the present invention,
The pressure roll 3'of a metal roll is simply arranged. Disperse 30 parts by weight of Portland cement, 30 parts by weight of granulated blast furnace slag, 30 parts by weight of fly ash, 10 parts by weight of waste material (waste material such as defective cement product and hardened), and 6 parts by weight of pulp in water. , A slurry 7 having a concentration of 8% by weight is formed, and the slurry 7 is put into a hopper 8.
And papermaking was carried out by the apparatus shown in FIGS. 1 and 3. The slurry 7 was supplied at a rate of 1.5 g / cm ² (solid content). In the case of the apparatus shown in FIG. 1, the manufactured green sheet 1 is dehydrated by vacuum suction in the suction box 10 and is further dehydrated while being pressed by the pressure roll 3 via the release film 4 to reduce the water content of the green sheet 1. Lowered. Further, in the case of the apparatus shown in FIG. 3, the suction content is reduced by vacuum suction in the suction box 10 and the moisture content of the green sheet 1 is reduced by further dehydration while applying pressure by the pressure roll 3 '. The degree of pressure reduction by vacuum suction in the suction box 10 was maintained at 30 cmHg over the entire zone. The water content of each part of the green sheet 1 was measured, and the result was as shown in the graph of FIG. FIG.
The vertical axis represents the water content of the green sheet 1, the horizontal axis represents the dehydration time, the solid line represents the present invention, and the broken line represents the comparative example. The water content of the green sheet 1 is {(solid content) / (solid content + water)} × 100 (%). As a result, the water content of the present invention was reduced by about 5% as compared with that of the comparative example. In addition, according to the present invention, the pressure roll 3
No material adhered to the surface, and no bank was formed on the green sheet 1, so that no crack was observed on the surface layer. On the other hand, in the comparative example, banks were formed in the green sheet 1 and fine cracks were formed in a part of the surface layer.

[0009]

As described above, the present invention has the elastic layer on the surface of the pressure roll when squeezing with the pressure roll as described above.
It can elastically deform the elastic layer to press the green sheet over a wide contact area, can effectively squeeze the green sheet to promote dehydration by squeezing, and can be applied via a release film. Since it is pressurized with a pressure roll,
Since the material does not adhere to the pressure roll from the green sheet side, maintenance of the pressure roll can be facilitated. Furthermore, when squeezing the green sheet with the pressure roll, a wide contact area can be applied and the mold release The sheet can be dehydrated by covering the side opposite to the suction-dehydrated side, and the dehydration effect can be further enhanced by the combination of dehydration by vacuum suction and dehydration by compression.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of the present invention.

2A is a cross-sectional view of a pressure roll, and FIG. 2B is a cross-sectional view of a state where an elastic layer of the pressure roll is deformed.

FIG. 3 is a partially cutaway front view of a device of a comparative example.

FIG. 4 is a graph showing the performance when dehydrated by the device of the present invention and when dehydrated by the device of the comparative example.

[Explanation of symbols]

 1 green sheet 2 elastic layer 3 pressure roll 4 release film

Claims (1)

[Claims] 1. A method of dehydrating while continuously feeding a green sheet produced by making a slurry, the method comprising sucking and dehydrating from one side of the green sheet, and using a pressure roll having a surface coated with an elastic layer. A dewatering method in the production of an inorganic plate, comprising squeezing the other surface of the green sheet between a pressure roll and the green sheet via a release film.