JP2005041110A - Flow-on sheet forming method of cement sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply remove the solid component flowing out to the back side of a sheet forming belt without requiring a large amount of washing water by solving a problem wherein it is necessary to wash the back of the sheet forming belt with washing water in order to prevent such a phenomenon that the solid component flowing out along with floating water due to a scrape-off means is deposited between the sheet forming belt and a suction box and load is applied to the sheet forming belt by the deposited solid component to abrade the belt. <P>SOLUTION: Slurry is supplied to the sheet forming belt 3 from a flow box 2 and, after the slurry is leveled by a vibration device 7, floating water is scraped off by the scrape-off means 10 and drained. A washing roll 16 is arranged just under the scrape-off means and rotated while brought into contact with the back of the sheet forming belt 3 to remove the solid component flowing out to the back side of the sheet forming belt along with moisture. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The invention of this application relates to a flow-on papermaking method for cement boards. More specifically, the invention of this application relates to a flow-on papermaking method for a cement board, which does not require a large amount of washing water and can easily remove solids flowing out together with moisture on the back side of the papermaking belt. .

  A flow-on papermaking method is known as a manufacturing technique of a cement board used for building exterior materials such as an outer wall material, a roof material, and a roofing material. In the flow-on papermaking method, a raw material containing reinforcing fibers such as cement and pulp and appropriately added with silica or the like is kneaded with water to have a relatively high concentration or a high concentration of about 25 to 65% solid content concentration. Supply cement slurry to papermaking belt. The papermaking belt has water permeability such as made of felt, is formed in an endless shape, and circulates while being suspended by a driving roll and a driven roll. The cement slurry supplied to this papermaking belt spreads over the papermaking width to form a green sheet. In the flow-on papermaking method, the green sheet is vibrated from the surface side by a vibration device in the leveling zone. The floating water that floats on the surface of the green sheet due to the smoothing of the surface is transferred downstream from the vibration device with respect to the traveling direction of the green sheet through the water-permeable sheet disposed on the surface side of the green sheet. Suction box disposed under the papermaking belt in the suction zone after draining the floating water scraped off by scraping means such as a scraper or roll disposed and draining the scraped water above the green sheet using a suction device. The water contained in the green sheet is dehydrated under reduced pressure below the papermaking belt.

  The surface texture of the dehydrated product is improved by scraping and removing by the scraping means and the suction device. However, when the floating water is scraped off by the scraping means, there is a problem that a load is applied to the papermaking belt and the life of the papermaking belt is shortened. As a cause of this, it is conceivable that solids flowing out together with moisture accumulate on the back side of the papermaking belt between the papermaking belt and the suction box, and the papermaking belt is worn by the accumulated solids.

Therefore, conventionally, the back surface of the papermaking belt is washed with washing water (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2002-210718

  However, cleaning of the papermaking belt requires a large amount of cleaning water, and complicated equipment for supplying the cleaning water is required.

  The invention of this application has been made in view of such circumstances, and does not require a large amount of washing water, and can easily remove solids flowing out together with moisture on the back side of the papermaking belt. Providing a flow-on papermaking method is a problem to be solved.

  The invention of this application is to solve the above problems. First, a cement slurry is supplied from a flow box to a papermaking belt that moves, and a green sheet that is developed on the papermaking belt is fed from its surface side by a vibration device. After the surface is smoothed by vibration, the floating water that floats on the surface of the green sheet by the surface smoothing by the vibration device is green by scraping means arranged downstream of the vibration device in the traveling direction of the green sheet. Scattered through the water-permeable sheet placed on the surface side of the sheet, drained the floating water above the green sheet by a suction device, then dehydrated the water contained in the green sheet under the papermaking belt under reduced pressure This is a flow-on papermaking method for a cement board, where a cleaning roll is placed directly under the scraping means, Rotates while in contact with the rear surface of the concrete belt, provides a flow-on papermaking method cement board and removing the solids flowing out together with water on the back side of the papermaking belt.

  The invention of this application is secondly, in the flow-on papermaking method of the first cement board, a second cleaning roll is disposed between the flow box and the scraping means, and the second cleaning roll is The present invention provides a flow-on papermaking method for a cement board that rotates while contacting the backside of the papermaking belt and removes solids flowing out together with moisture on the backside of the papermaking belt.

  According to the flow-on papermaking method for the first cement board of the invention of this application, a large amount of washing water is not necessary, and the solids flowing out together with moisture on the back side of the papermaking belt can be easily removed.

  According to the flow-on papermaking method for the second cement board of the invention of this application, in addition to the effect of the flow-on papermaking method for the first cement board, the solid content flowing out together with the drainage on the back side of the papermaking belt is the papermaking belt. And the suction box can be more effectively suppressed.

  Hereinafter, the flow-on papermaking method for a cement board according to the invention of this application will be described in more detail.

  1 and 2 are a side view and a plan view, respectively, showing an outline of a flow-on papermaking method for a cement board according to the invention of this application.

  For example, as shown in FIGS. 1 and 2, in the flow-on papermaking method for the cement plate of the invention of this application, similar to the conventional flow-on papermaking method, it contains reinforcing fibers such as cement and pulp, and silica or the like is used. An appropriately added raw material is kneaded with water, and a papermaking belt in which a cement slurry (1) having a solid content concentration of about 25 to 65% and having a relatively high concentration or high concentration is moved from the flow box (2) ( To 3). The papermaking belt (3) is made of felt, plastic, metal or the like and has a water permeability, is formed in an endless shape, and circulates around the drive roll (4) and the driven roll (5). The cement slurry (1) supplied to the papermaking belt (3) is then developed to a papermaking width to become a green sheet (6).

  In the flow-on papermaking method for the cement board of the invention of this application, in the leveling zone, the green sheet (6) is vibrated from the surface side thereof by the vibration device (7) to smooth the surface. The moisture in the green sheet (6) floats up to the surface layer due to the smoothing of the surface. The floating water (8) is a water-permeable sheet (9) having water permeability disposed on the surface side of the green sheet (6). Is scraped off by scraping means (10) such as a scraper and a roll disposed downstream of the vibration device (7) with respect to the traveling direction of the green sheet (6). The floating water (8) thus scraped off is drained above the green sheet (6) using the suction device (11). As shown in FIG. 2, the suction device (11) is provided with a plurality of holes (12), slits, and the like on the back surface side, and the floating water (8) has these holes (12), slits, etc. And is drained above the green sheet (6).

  In the above leveling zone, a natural dewatering box (13) is provided below the papermaking belt (3). The natural dewatering box (13) drains water contained in the green sheet (6) by being naturally flown down through the papermaking belt (3) by vibration by the vibration device (7). Is.

  Next, in the flow-on papermaking method for the cement board of the invention of this application, in the suction zone, the water contained in the green sheet (6) is dehydrated by reducing the pressure below the papermaking belt (3), and the dehydrated product (14) Get. In this suction zone, a suction box (15) is provided below the papermaking belt (3), and receives and drains water that moves from the green sheet (6) to the back side of the papermaking belt (3) by dehydration under reduced pressure. .

  And in the flow-on papermaking method of the cement board of the invention of this application, as shown in FIG. 1, the cleaning roll (16) is disposed directly under the scraping means (10) such as a scraper or roll. The cleaning roll (16) rotates while being in contact with the back surface of the papermaking belt (3), and removes solids such as filler flowing out together with moisture on the back surface side of the papermaking belt (3).

  Thus, in the flow-on papermaking method for the cement board of the invention of this application, the washing belt (16) is used to remove solids such as filler flowing out along with moisture on the back side of the papermaking belt (3). It is possible to suppress the solids flowing out together with the drainage from the back side of (3) from being deposited between the papermaking belt (3) and the suction box (15), and wear of the papermaking belt (3) is suppressed. . Since the wear of the papermaking belt (3) can be suppressed by the cleaning roll (16), not by cleaning with the cleaning water, water is sprinkled to clean the cleaning roll (16), but a large amount as in the conventional case. Water is not needed. Therefore, a large facility for supplying cleaning water is not necessary, and wear of the papermaking belt (3) can be easily suppressed.

  In the flow-on papermaking method for the cement board of the invention of this application, as shown in FIG. 3, the second cleaning roll (17) is disposed between the flow box (2) and the scraping means (10). Can do. Similarly to the cleaning roll (16), the second cleaning roll (17) rotates while contacting the back surface of the papermaking belt (3), and the solid content flowing out together with moisture is transferred to the back surface side of the papermaking belt (3). Remove. By the combined use of the cleaning roll (16) and the second cleaning roll (17), the solid content flowing out together with the drainage on the back side of the papermaking belt (3) is between the papermaking belt (3) and the suction box (15). Accumulation can be suppressed more effectively. The wear suppression of the papermaking belt (3) is improved. The arrangement position of the second cleaning roll (17) is not particularly limited as long as it is between the flow box (2) and the scraping means (10). For example, as shown in FIG. Even if it arrange | positions in the downstream of a vibration apparatus (7) regarding the moving direction of (6), as shown in FIG. 4, you may arrange | position in the upstream of a vibration apparatus (7). Of course, it can also be arranged directly under the vibration device (7). Further, the number of the second cleaning rolls (17) is not limited to one and can be two or more. In this case, it is assumed that the second cleaning roll (17) is disposed between the flow box (2) and the scraping means (10).

[Examples 1 and 2 and Comparative Example 1-3]
A raw material containing 50% by weight of ordinary Portland cement, 5% by weight of pulp and 45% by weight of silica was dispersed in water to prepare a cement slurry having a solid concentration of 40%. This cement slurry is supplied from the flow box to the papermaking belt, the surface of the green sheet is smoothed with a vibration device, and the floating water is scraped off and sucked through the water-permeable sheet placed on the surface side of the green sheet. After suctioning and draining upward using a device at a vacuum of 20 kPa, vacuum dehydration was also performed from below the papermaking belt at a vacuum of 40 kPa. The papermaking belt was made of felt, moved at a speed of 30 m / min, and continuously operated for 10 days.

  In Example 1, as shown in FIG. 1, the cleaning roll was disposed directly under the scraping means and brought into contact with the back surface of the papermaking belt. In Example 2, as shown in FIG. 3, the cleaning roll is disposed in the same manner as in Example 1, and the second cleaning roll is disposed between the flow box and the scraping means, and is provided on the back surface of the papermaking belt. Made contact. The cleaning roll and the second cleaning roll were made of sponge and had a diameter of 50 mm.

  In Comparative Example 1, instead of the cleaning roll in Example 1, a support plate made of ultra high molecular weight polyethylene (width 50 mm, thickness 30 mm in the traveling direction of the green sheet) was used. In Comparative Example 2, instead of the cleaning roll in Example 1, a support plate made of alumina (width 50 mm, thickness 30 mm in the traveling direction of the green sheet) was used, and in Comparative Example 3, a support plate made of SUS304 (Green A width of 50 mm and a thickness of 30 mm) were used in the traveling direction of the sheet.

  The amount of wear of the papermaking belt, the amount of wear of the cleaning roll or the support plate, the maintenance time of the cleaning roll or the support plate, and the maintenance time of the suction box were measured and evaluated. The results are shown in Table 1.

  As shown in Table 1, Examples 1 and 2 have a smaller amount of wear on the papermaking belt than Comparative Example 1-3, and Example 2 is particularly small. In addition, the wear amount of the cleaning roll is smaller than that of the support plate, and the maintenance is excellent. Furthermore, also in the maintainability of the suction box, Examples 1 and 2 are superior to Comparative Example 1-3, and Example 2 is particularly superior.

  Of course, the invention of this application is not limited by the above embodiments. It goes without saying that various aspects are possible for the details.

  As explained in detail above, the cement plate flow-on papermaking method of the invention of this application can easily remove solids flowing out together with moisture on the back side of the papermaking belt without requiring a large amount of washing water.

It is the side view which showed the outline | summary of the flow-on papermaking method of the cement board of this invention. It is the top view which showed the outline | summary of the flow-on papermaking method of the cement board of this invention. It is the side view which showed one form of the flow-on papermaking method of the cement board of this invention. It is the side view which showed one form of the flow-on papermaking method of the cement board of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cement slurry 2 Flow box 3 Papermaking belt 4 Drive roll 5 Driven roll 6 Green sheet 7 Vibrating device 8 Floating water 9 Water-permeable sheet 10 Scraping means 11 Suction device 12 Hole 13 Natural dehydration box 14 Dehydrated product 15 Suction box 16 Cleaning roll 17 Second cleaning roll

Claims (2)

  The cement slurry is supplied from the flow box to the moving papermaking belt, and the green sheet developed on the papermaking belt is vibrated from the surface side with a vibration device to smooth the surface, and then vibrates with respect to the traveling direction of the green sheet. By means of scraping means arranged on the downstream side of the apparatus, the floating water that floats on the surface of the green sheet by leveling the surface by the vibration device was scraped off and scraped off through the water-permeable sheet arranged on the surface side of the green sheet. Floating water is drained to the upper side of the green sheet with a suction device, and then the water contained in the green sheet is dewatered under reduced pressure to the lower side of the papermaking belt. The cleaning roll is placed in contact with the backside of the papermaking belt and rotates to contact the backside of the papermaking belt. Flow on papermaking method cement board and removing the solids flowing out together.   A second cleaning roll is disposed between the flow box and the scraping means, and the second cleaning roll rotates while contacting the back surface of the papermaking belt, and the solid content that flows out together with moisture to the back surface side of the papermaking belt. The method for flow-on papermaking of a cement board according to claim 1, wherein the material is removed.