JPH07285112A - Manufacture of green plate and manufacturing device of green plate - Google Patents

Abstract

PURPOSE:To improve the quality of a product, by a method wherein in a manufacture of a green plate by a flow-on method, a waving phenomenon wherein a supply thickness of slurry is changed periodically and lift of reinforcing fibers are prevented effectively. CONSTITUTION:In a manufacture of a green plate wherein slurry is supplied onto a sheet 4 advancing in a longitudinal direction and having permeability to water through a hopper 7 into a desired thickness and then the slurry is prepared so that it is decompressed and dehydrated to the lower part of the sheet 4 at a downstream side of the hopper 7 and the slurry dwelling on the inside of the hopper 7 is supplied onto the sheet 4 while dehydrating to the lower part of the sheet 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a raw plate manufacturing method and a raw plate manufacturing apparatus.

[0002]

2. Description of the Related Art Conventionally, there is a flow-on type manufacturing method as a method of manufacturing plate-shaped building elements such as outer wall materials and roof tiles.
In this flow-on type manufacturing method, the solid content concentration is 20 to
A relatively high concentration of 45% slurry is supplied in a single layer and in a desired thickness onto a water-permeable annular sheet that advances in the longitudinal direction, and this slurry is depressurized and dehydrated by suction means provided on the lower surface of the sheet. To form a continuous plate-shaped raw plate,
There is one that obtains a plate-shaped building element by cutting this green plate to a predetermined size and then curing it (for example, Japanese Patent Laid-Open No. 4-153).
(See Japanese Patent Publication No. 004), the suction means is configured by connecting a large number of movable suction boxes on the lower surface side of the seat in the seat moving direction so as to move in synchronization with the seat.

In this flow-on system, unlike a papermaking method in which a thin slurry attached to a papermaking sheet is wound around a making roll many times (for example, JP-A-4-47905), a slurry having a relatively high concentration is prepared. Since it is suddenly supplied on the sheet in a desired thickness, there is an advantage that a building element in which delamination does not easily occur can be obtained.

[0004]

When a large number of movable suction boxes are connected in the sheet advancing direction to form the suction means, the water absorption holes provided in the top plate of the box cannot be provided too close to the edges, and therefore the movable suction boxes are movable. At both ends of the suction box in the seat advancing direction, the dehydration effect is inevitably lower than that at the center in the same direction.

However, in the conventional flow-on type manufacturing method, the slurry supplied onto the sheet is suddenly depressurized and dehydrated by the suction means composed of such a movable suction box group. The slurry thickness differs between the both end portions and the central portion, which may cause a so-called waviness phenomenon in which the slurry thickness periodically changes in the sheet advancing direction.

When the slurry whose supply thickness is cyclically changed in this way is dehydrated under reduced pressure by the suction means, the thickness of the raw plate after dehydration is also cyclically changed, and as a result, the thickness of the building plate material as the final product is also non-uniform. It becomes a cause to deteriorate the product quality. Further, in the past, since the slurry in the hopper is placed on the sheet without being dehydrated at the beginning of the supply, for example, when the water content at the time of blending is high and the consistency of the slurry is high, the shape of the slurry at the beginning of the supply Is likely to change, and the slurry supply thickness may change due to a slight vibration of the sheet, and this point also causes the corrugation phenomenon.

When the slurry in the hopper is directly supplied onto the sheet, when the specific gravity of the reinforcing fibers mixed in the slurry is small, the reinforcing fibers float up while the slurry stays in the hopper, and the reinforcing fibers rise on the sheet. The desired content of reinforcing fibers may not be reached when the slurry is deposited on the. In view of such an actual situation, the present invention effectively prevents the corrugation phenomenon in which the slurry supply thickness periodically changes and the lifting of reinforcing fibers in the flow-on method (excluding the papermaking method) of the raw plate manufacturing method. The purpose is to improve product quality.

[0008]

[Means for Solving the Problems] In order to achieve the above object,
The present invention has taken the following technical means. That is, the method of the present invention, a slurry having a constant thickness is supplied onto a sheet having water permeability that advances in the longitudinal direction through a hopper, and then the slurry is depressurized and dehydrated below the sheet on the downstream side of the hopper. In the raw plate manufacturing method described above, the slurry retained in the hopper is supplied onto the sheet while being dehydrated below the sheet.

Further, in the apparatus of the present invention, a water-permeable sheet is provided so as to be movable in the longitudinal direction thereof, a hopper for supplying the slurry to the upper surface of the sheet is provided above the sheet, and the slurry is decompressed and dehydrated from the lower surface side of the sheet. In the raw plate manufacturing apparatus in which the suction means is provided on the downstream side of the hopper, the dewatering means for dewatering the slurry retained in the hopper to the lower side of the sheet is provided directly below the hopper and on the lower surface side of the sheet. Is characterized by.

Specifically, it is preferable that the dewatering means is composed of a suction box for dewatering the slurry from the lower surface side of the sheet under reduced pressure. However, as long as a certain degree of dewatering effect can be obtained, water absorption holes for supporting the sheet from below are provided. You may comprise from the support plate with. If it is desired to further accelerate the dehydration of the slurry, a pressurizing means for pressurizing the inside of the hopper may be provided.

[0011]

In the present invention, since the slurry staying in the hopper is dewatered to the lower side of the sheet and is fed onto the sheet, the slurry immediately after feeding is already dewatered to some extent. It is difficult to deform. Therefore, even if the sheet is then hung on the movable suction box group having a different water absorption effect depending on the plane position or the sheet is vibrated, the slurry thickness does not change so much.

Further, when the slurry retained in the hopper is dehydrated to the lower side of the sheet, the reinforcing fibers are pulled toward the sheet, so that even reinforcing fibers having a low specific gravity can be reliably collected in the vicinity of the sheet.

[0013]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 shows a raw plate manufacturing apparatus 2 to which the present invention is applied. This green board manufacturing apparatus 2 has a frame 3 framed on the floor, a water-permeable endless sheet 4 having slurry supplied to the upper surface, and a large number of dewatering slurry from the lower surface of the sheet 4 under reduced pressure. A movable suction box 5, an annular belt 6 that advances in contact with the upper surfaces of the left and right (width direction) end portions of the seat 4, a supply hopper 7 for supplying slurry to the upper surface of the seat 4, and a lower portion of the hopper 7. Fixed stationary suction box 1 and auxiliary suction box 1A that are positioned and contact the underside of the seat 4.
Is provided.

The frame 3 is formed by connecting a plurality of portal frames 3A continuously in the material conveying direction (direction shown by arrow A in FIG. 2), and is located at the lower portion of each portal frame 3A and the front and rear ends in the material conveying direction. On the upper part of the gate-shaped frame 3A, a guide roll 8 which is rotatable around an axis parallel to the width direction of the seat 4 is arranged. The sheet 4 is formed by annularly forming a water-permeable long strip-shaped member such as felt or woven cloth,
The guide motor 8 is guided by the guide roll 8 and is driven by the drive motor 9 installed on the floor so that the upper side circulates in the longitudinal direction (direction of arrow A in FIG. 2).

In the loop of the seat 4 and in the front and rear portions of the frame 3, large diameter front and rear sprockets 11 and 12 rotatable about a horizontal axis 10 parallel to the seat width direction are pivotally supported, and the sprockets 11 and 12 are supported. Conveyor chain 13 wrapped around
The movable suction box 5 is fixed to the outer peripheral side of the. The front sprocket 11 on the downstream side is rotationally driven via a chain 15 by a motor 14 provided on the upper part of the frame 3, and by the rotation of the front sprocket 11, each movable suction box 5 comes into contact with the lower surface of the seat 4 and the seat 4 It circulates in the same direction and at the same speed.

Suction rails 16 having a hollow cross-section, whose interior is decompressed by a Nash pump (not shown), are provided on the left and right sides of the upper end of each gate-shaped frame 3A located between the front and rear sprockets 11, 12 along the front-back direction of the frame 3. Each movable suction box 5 circulated by the sprockets 11 and 12 slidably moves on the suction rail 16.

Each movable suction box 5 is composed of a hollow box body having a large number of water absorption holes in its top plate, and has long holes in the sheet advancing direction communicating with decompression holes provided in the suction rails 16 on both left and right sides of the bottom plate. I have it. Therefore, the inside of each suction box 5 is depressurized at a substantially constant pressure due to the communication of the depressurization hole and the elongated hole while sliding on the suction rail 16, and the material supplied to the upper surface of the sheet 4 is The water is vacuum-dewatered from the lower side of the sheet 4 through the water absorption holes of the suction box 5.

The belt 6 is for specifying the width of the slurry-like material supplied to the upper surface of the sheet 4, and is made of a material having water-tightness and elasticity such as synthetic rubber, and is shown in the drawing. Although not shown, a projecting part having a rectangular cross section is provided on the upper surface in the center of the width direction of the strip-shaped part that comes into contact with the upper surface of the sheet 4 to form a T-shaped cross section. A pair of left and right pulleys 17 for guiding the belt 6 are separately provided on the lower portion of each gate-shaped frame 3A and on the upper portion of the gate-shaped frame 3A located at the front and rear ends, and a guide roll 8 for supporting the seat 4. The belt 6 guided by the pulley 17 is driven at the same speed and in the same direction as the seat 4 so that the belt-shaped portions on both sides in the width direction of the seat 4 contact the upper surfaces of both ends in the width direction of the seat 4. It is driven by and is circulated.

A plurality of press rolls 18 are continuously provided in the front-rear direction above the front end of the frame 3, and the material passing under the rolls 18 is subjected to decompression dehydration by the movable suction box 5 and also to each press roll 18. It is further dehydrated by reduction. Further, a sprinkler 19 for washing the seat 4 is provided below the frame 3, particularly below the sprocket 11. It should be noted that the cleaning means for the movable suction box 5 can be arranged in an appropriate place.

On the front side of the frame 3, that is, on the downstream side of the sheet 4, the raw plate cutting conveyor 2 is at the same level as the upper surface of the sheet 4.
0 is arranged, the raw plate that has passed through each press roll 18 is cut into an appropriate length dimension on this conveyor 20, and further dehydrated and patterned by a downstream press device, After undergoing processes such as autoclave curing, product boards such as outer wall materials and roof tiles are finished.

As shown in FIGS. 1 and 3 to 8, the fixed suction box 1 is positioned directly below the hopper 7 and is a support member 3B composed of vertically oriented bolts and the like.
It is attached to the frame 3 via the, and the vertical attachment position with respect to the seat 4 can be changed. The fixed suction box 1 is composed of a hollow box 21 whose interior is decompressed by a suction blower 41, which will be described later. The top plate 22 of the hollow box 21 has the slurry supplied to the upper surface of the sheet 4 in the sheet 4. A large number of water absorption holes 26 are provided on the lower surface side for water removal.

Inside the hollow box body 21, there is provided an opening degree adjusting means 22A for adjusting the opening degree of the water absorbing hole 26, and the opening degree adjusting means 22A has a movable plate having an opening 46 corresponding to the water absorbing hole 46. 23 is movably provided on the lower surface of the top plate 22. On the upper surface of the top plate 22, a large number of parallel water draining grooves 24 extending over the entire width of the seat are provided, and at the bottom of the water draining groove 24, a large number of water absorbing holes 26 are provided at arbitrary intervals. 8 (a) and (b)).
Further, the draining groove 24 on the upstream side of the top surface of the top plate 22 has the center portion in the seat width direction as the apex so that the seat 4 is pulled in the width direction when the seat 4 slides on the top plate 22 and advances. Are formed so as to incline toward the upstream side with respect to both ends.

At both ends of the hollow box body 21 in the seat width direction, there are provided top end projecting portions 21A extending outside the top plate 22,
A belt guide 27 is attached to the upper surface thereof in an overhanging manner and is replaceable, and a top plate 22 is also replaceably attached. As shown in FIGS. 3 and 6, the bottom plate 2 of the hollow box body 21.
8 is inclined so that the upstream side (arrow A direction) in the sheet moving direction is lower than the top plate 22, and the drainage collecting pipe 29 whose upper end is cut open at the upstream end has the entire width (width direction of the seat 4). ) Is provided over. Rubber plugs 30 for cleaning are attached to both ends of the collecting pipe 29 so as to be openable and closable,
A drainage pipe 32 is provided in a drainage hole 31 provided at one end of the collecting pipe 29 for discharging the absorbed cement-containing water to the outside of the machine.
Are connected.

Further, inside the hollow box body 21, there is provided a gas-liquid separating means 28A for separating the moisture and air sucked therein, and the separating means 28A communicates with the pressure reducing hole 33. Separation pipe 34 erected on the upper surface of the bottom plate 28
And a cap member 35 for covering the upper end opening of the separation pipe 34 from above.
It consists of and. That is, as shown in FIG.
The bottom plate 28 of the hollow box body 21 is provided with five pressure reducing holes 33 arranged at equal intervals in the center of the sheet moving direction in the sheet width direction. Separation tubes 34 that rise up to the inner side) are fixed respectively. The cap member 35 has a U-shaped cross section that is slightly larger than the separation pipe 34, and is fixed in a state of being separated from the separation pipe 34 so that the lower end edge thereof is located slightly lower than the upper end edge of the separation pipe 34. There is.

Therefore, when the pressure inside the hollow box 21 is reduced,
The air passes between the cap member 35 and the separation pipe 34 and the decompression hole 33.
The water on the bottom plate 28 of the hollow box 21 flows down toward the collecting pipe 29 without flowing into the depressurizing hole 33, and the water dripping from the water absorbing hole 26 of the top plate 22 is discharged by the cap member 35. Since it is prevented from flowing into the separation tube 34, the water and air are reliably separated in the hollow box body 21.

The cap member 35 may have various shapes such as a bowl shape and a conical shape in addition to the tray shape.
It is sufficient that the upper end opening can be covered from above so that the drip water does not flow into 4. As shown in FIGS. 1 and 6,
A manifold 36 communicating with all the pressure reducing holes 33 is detachably attached to the lower surface of the bottom plate 28 of the hollow box body 21, and an intake pipe 38 is connected to an intake port 37 provided in the lower surface in the center of the manifold 36 in the longitudinal direction. Has been done. Intake pipe 38
Is connected to a suction blower 41 via an intake collecting pipe 39 and a water-water separating cyclone 40, as shown in FIGS.

The water separated by the cyclone 40 is discharged through a drain pipe 43 having a flap valve 42 (see FIG. 7) at the discharge end, as shown in FIG. Also,
The lower end portion 32A of the drain pipe 32 has a structure shown in FIGS.
The flap valve 42 shown in FIG. Each of the flap valves 42 is provided with a drainage amount detecting means 43A (a limit switch for detecting the opening degree of the valve 42 in the illustrated example), and the detecting means 43A detects the opening degree of the flap valve 42 to measure the dehydration amount. By doing so, it is possible to manage the composition of the slurry and the abnormality of the slurry supply amount.

That is, the dehydration amount of the slurry changes depending on the degree of pressure reduction of the suction box 1 and the opening degree of the water absorption holes 26. The slurry blending and the slurry supply amount per unit time and the slurry dewatering at a certain degree of pressure reduction and opening degree. If the relationship with the amount is grasped in advance through experiments and experience, it is known that the water content of the slurry is too high or the amount of the slurry supplied is too large based on the excessive amount of dehydration detected by the detection means 43A. it can.

As shown in FIGS. 1 and 5, the hollow box body 21
On the upper surface of the bottom plate 28 of the
A partition plate 44 is provided in the sheet advancing direction for partitioning the movable plate 23 in a slidable manner while partitioning the movable plate 23 slidably in the width direction of the hollow box body 21. The inside of the body 21 can be depressurized uniformly.

The upper and lower edges of the partition plate 44 are provided with notched portions 45 having a semicircular shape or the like, which allows air or moisture to flow partially. The movable plate 23 is in the form of a strip plate, its width is about twice the pitch of the groove 24, and its length is about half the pitch of the water absorption holes 26 in the groove 24. Has been shorter than. Each movable plate 23 has openings 46 having the same pitch and the same diameter as the water absorption holes 26 of the top plate 22, and the operation rod 48 is rotatable and axially movable in a bracket 47 provided at one end side in the longitudinal direction thereof. Impossiblely linked.

The operating rod 48 penetrates the side wall of the hollow box body 21 through a sealing material (not shown), and a male screw portion 48A provided at the outer end portion thereof has a top end projecting portion 21A of the hollow box body 21. It is screwed into the screw hole of the jack bracket 44 fixed to the lower surface. A turning tool mounting portion 48B is provided at the outer end of the male screw portion 48A. Therefore, when the operating rod 48 is turned by a turning tool such as a wrench, the movable plate 23 moves individually with the adjusting rods 48 in the seat width direction (arrow B direction in FIG. 5) with respect to the top plate 22. By this, the overlapping state of the water absorption hole 26 and the opening 46 is changed so that the opening degree of the water absorption hole 26 can be adjusted (see FIGS. 8A and 8B).

The auxiliary suction box 1A is shown in FIG.
And, as shown in FIG. 4, a hollow box body 50 separate from the fixed suction box 1 is provided, and a top plate 51 has a plurality of elongated strips extending in the width direction of the seat 4 between the opposite ends in the width direction. It is arranged so that a water absorption gap 52 is formed. The bottom plate 53 of the hollow box body 50 is inclined so that the downstream side is lower than the top plate 51, and a drainage collecting pipe 54 whose upper side is cut open at the downstream side end is provided over the entire width of the seat. A drain pipe 55 is provided at one end of the collecting pipe 54.
Are connected. The drain end 55 of the drain pipe 55
A flap valve 56 (the same as the flap valve 42 shown in FIG. 7) is attached to A.

In the bottom plate 53 of the hollow box body 50, three pressure reducing holes 57 are provided at equal intervals in the seat width direction at the central portion in the sheet moving direction. In this auxiliary suction box 1A, a gas-liquid separating means including a separation tube and a cap member similar to that of the fixed suction box 1 is provided. Further, on the lower surface of the bottom plate 53 of the hollow box body 50,
A manifold 58 communicating with all the pressure reducing holes 57 is detachably attached, and an intake pipe 59 is connected to a lower surface of the center of the manifold 58. The intake pipe 59 is the intake collecting pipe 39.
It is connected to the.

The flap valve 55 can also be provided with a drainage amount detecting means. As shown in FIG. 9 to FIG. 11, the hopper 7 has a rectangular shape in plan view with the upper and lower sides opened, and has a side wall lower end on both sides in the seat width direction and a rear wall lower end on the downstream side in the seat advancing direction for preventing water leakage. The rubber skirt plates 60 and 61 are attached. At the lower end of the front wall of the hopper 7 on the upstream side in the sheet moving direction, a gate member 62 for specifying the slurry supply thickness is provided. The gate member 62 is provided at the lower end of a mounting member 64 mounted movably up and down via elevating drive means 63 provided on both sides of the front wall of the hopper 7, and by a turnbuckle 65 provided on the mounting member 64. The outgoing side edge 62A is vertically swingable.

The output side edge 62A of the gate member 62 is gently curved so that the central portion in the sheet width direction protrudes more toward the downstream side in the sheet moving direction than the both ends, whereby the slurry flows from the gate member 62 into the sheet width. It is designed so that it can be sent out with a uniform thickness over the entire width in the direction. That is, the slurry in the hopper 7 is
Originally, both sides in the seat width direction are less likely to flow out than the central part. Therefore, by increasing the outflow resistance of the slurry in the central portion of the gate member 62, the outflow resistance of the slurry is made uniform over the entire area of the gate member 62, thereby making the supply thickness of the slurry uniform.

Next, the operation of the above embodiment will be described. A slurry prepared by kneading cement, water, aggregates, reinforcing fibers and the like with a constant mixture is fed from a chute (not shown) and stays in the hopper 7. The slurry in the hopper 7 is used for the sheet 4 and the gate member 62. It is supplied onto the sheet 4 which flows out to the upstream side from the space and advances to the upstream side while its thickness is regulated by the gate member 62.

At this time, since the fixed type suction box 1 provided immediately below the hopper 7 and on the lower surface side of the sheet depressurizes and dewaters the slurry retained in the hopper 7 downward, the slurry immediately after being supplied is already dewatered to some extent. It's done, and it's harder and less deformable than when mixed. Therefore, even after that, even if the auxiliary suction box 1A or the movable suction box group 5 having a different water absorption effect depending on the plane position is used, it is reliably prevented that the slurry thickness is excessively changed. The same applies when the seat 4 vibrates.

When the slurry staying in the hopper is dehydrated to the lower side of the sheet, the reinforcing fibers are pulled toward the sheet, so that even the reinforcing fibers having a low specific gravity can be reliably collected in the vicinity of the sheet. Therefore, for example, as shown in FIG. 12, the reinforcing fibers F can be biased to one side in the thickness direction of the slurry S. That is, the slurry S, which is dehydrated in the suction box 1 and sent out from the gate member 62, gathers on the side where the reinforcing fibers F mixed therein are in contact with the sheet 4 (the back surface side of the green plate) and the frictional force with the gate member 62. The sheets are arranged in the sheet advancing direction, and the bending strength of the product can be increased.

Further, since the density of the reinforcing fibers F on the upper surface side of the green plate is small, the patterning press working in the subsequent step is facilitated, and cracks can be prevented from being generated during the pressing, resulting in an improved finish. is there. On the other hand, sheet 4
Of the fixed type suction box while the slurry is supplied from the hopper 4, the
As shown in (b), the lower surface is squeezed by the draining groove 24 provided on the upper surface (contact surface) of the top plate 22, whereby water containing cement is squeezed out downward, and The slack is corrected.

Further, since the water absorption hole 26 is provided in the water drainage groove 24, the lower surface side of the advancing sheet 4 is decompressed through the water drainage groove 24 extending in the sheet width direction, and the entire lower surface of the sheet is evenly decompressed. That is, when the water absorption holes 26 directly contact the lower surface of the seat 4, the pressure reducing effect at the position where the water absorption holes 26 are not provided is reduced, but when the pressure is reduced through the draining groove 24 extending in the seat width direction, the water absorption holes 26 are formed in the seat width direction. The degree of pressure reduction becomes uniform, and in addition to this, the sheet 4 itself advances in its longitudinal direction, so that the entire lower surface of the sheet 4 is uniformly depressurized.

In the present embodiment, since the draining groove 25 on the most downstream side is displaced in the seat width direction center part to the upstream side in the seat moving direction rather than both side parts in the same direction, the seat 4 is fixed. The frictional force received from the box 1 acts on both sides in the seat width direction when the sheet 4 moves in contact with the seat 1 and is pulled to both sides in the same direction.
The slack in the width direction is corrected.

Next, the water dewatered from the slurry is sucked by the suction blower 41, and the water absorption holes 26 of the top plate 22 are absorbed.
And is taken into the hollow box body 21 through the opening 46 of the movable plate 23. At this time, the pressure reduction inside the hollow box body 21 is made uniform by the intake holes 37 and the partition plate 44, and the lower surface of the seat 4 is squeezed by the corner portions 24A (see FIG. 8b) of each groove 24 of the top plate 22. It is drained efficiently and dehydrated efficiently and uniformly.
Further, when it is desired to change the dehydration amount of the slurry by adjusting the opening degree of the water absorption hole 26, the movable plate 23 is set to the adjustment rod 4.
It suffices to rotate 8 to move it in the width direction of the seat 4.

Further, in the hollow box body 21, since the sucked water and air are separated by the gas-liquid separating means 28A, only the air is supplied again to the suction blower 41, which causes a failure of the suction blower 41. The cement-containing water flows on the upper surface of the bottom plate 28 toward the drainage collecting pipe 29, and the drainage pipe 32
Is excreted to the outside through the flap valve 42. The slurry that has passed through the suction box 1 is further dehydrated in the auxiliary suction box 1A and subsequently dehydrated in the movable suction box 5.

Next, a slurry prepared by kneading with the following composition was supplied to the hopper 7 to prepare a green board by the above-mentioned green board manufacturing apparatus 2 to actually manufacture a plate-shaped building element (outer wall material). . Cement 47% by weight Quartz sand 40% by weight Pulp (reinforcing fiber) 12% by weight Foam polystyrene particles 1% by weight Slurry supply thickness about 14 mm As a result, building elements having the strength shown in Table 1 were obtained.

[0045]

[Table 1]

The bending strength in Table 1 is obtained from the strength of the core obtained by cutting out arbitrary parts of the building element. As can be seen from this table, the lateral / aspect ratio of the bending strength, particularly in the lower side in the slurry thickness direction, is significantly smaller than 1, which results in
The aspect ratio is also greater than 1. This is based on the fact that the pulp is unevenly distributed on the lower side in the thickness direction of the slurry by supplying the slurry onto the sheet 4 while being dehydrated inside the hopper 7, and at that time, the pulp is oriented by the progress of the sheet 4. It is a thing.

Since the bending strength of the building element can be intentionally strengthened in the specific direction in this manner, the added value of the product can be increased. Further, the pulp density was low on the upper side in the slurry thickness direction, and therefore, no cracks were generated on the surface of the plate material in the patterning press working in the subsequent step.

The present invention is not limited to the above embodiment. For example, as shown in FIG. 13, instead of the fixed suction box 1, a support plate 60 with a water absorption hole 61 that supports the seat 4 from below may be provided. In this case, since the support plate 60 does not have a depressurizing function, the dehydration effect from the water absorption hole 61 is inferior to that of the suction box 1, but if the head height H of the slurry is held, the dehydration effect will be somewhat due to the head thickness. Is obtained.

In this case, the hopper 7 is connected to a pressurizing means 62 such as an air compressor, and the pressurizing means 62 pressurizes the inside of the hopper 7 to press the slurry against the upper surface of the sheet 4, thereby promoting the dehydration. You can also plan.

[0050]

As described above, according to the present invention,
Since the slurry retained in the hopper is supplied onto the sheet while being dehydrated to the lower side of the sheet, the dehydration of the slurry immediately after the supply is completed to some extent. For this reason, since the slurry is harder and less likely to be deformed than when mixed, even if the slurry is applied to a movable suction box that has a different water absorption effect depending on the plane position or there is vibration of the sheet, the slurry thickness changes too much. It does not occur, the waviness phenomenon in which the slurry supply thickness changes periodically is prevented, and the fluctuation of the product plate thickness can be suppressed to the minimum.

Further, when the slurry retained in the hopper is dehydrated to the lower side of the sheet, the reinforcing fibers are pulled toward the sheet side, so that the reinforcing fibers can be collected in the vicinity of the sheet and the bending strength of the product is improved. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view of a fixed suction box (A in FIG. 5).
-A line sectional view).

FIG. 2 is an overall side view of a raw plate manufacturing apparatus.

FIG. 3 is a side view of a rear portion (downstream side) of the raw plate manufacturing apparatus.

FIG. 4 is a top plan view of FIG.

FIG. 5 is a partially cutaway plan view of the fixed suction box.

FIG. 6 is an enlarged view of the right side surface of FIG.

FIG. 7 shows a flap valve, (a) is a front view thereof,
(B) is a right side view.

8 is an enlarged cross-sectional view of the top plate, FIG. 8A is a cross-sectional view taken along line CC of FIG. 5, and FIG. 8B is a cross-sectional view taken along line DD of FIG.

FIG. 9 is a plan view of a hopper.

FIG. 10 is a side view of the hopper.

11 is an enlarged cross-sectional view taken along the line EE of FIG.

FIG. 12 is a cross-sectional view of a slurry showing uneven distribution of reinforcing fibers.

FIG. 13 is a side view showing a modified example of the dehydrating means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed type suction box (dehydration means) 2 Raw plate manufacturing apparatus 4 Sheet 7 Hopper 60 Support plate (dehydration means) 61 Water absorption hole 62 Pressurizing means

Claims (5)

[Claims] 1. A slurry is supplied to a desired thickness on a sheet (4) having water permeability which advances in the longitudinal direction through a hopper (7), and then the slurry is fed to the hopper (7).
In the raw plate manufacturing method in which the sheet (4) is dehydrated under reduced pressure on the downstream side of the sheet (4), the sheet (4) is dehydrated while the slurry retained in the hopper (7) is dehydrated below the sheet (4). A method for producing green boards, characterized by supplying the above. 2. A sheet (4) having water permeability is provided so as to be movable in the longitudinal direction thereof, and a hopper (7) for supplying slurry to the upper surface of the sheet (4) is provided above the sheet (4). A raw plate manufacturing apparatus provided with a suction means (5) for depressurizing and dehydrating slurry from the lower surface side on the downstream side of a hopper (7), in which a hopper (5) is provided directly below the hopper (7) and on the lower surface side of the sheet (4). 7) A raw plate manufacturing apparatus, characterized in that dehydration means is provided below the sheet (4) for dehydrating the slurry retained in the sheet (4). 3. The raw plate manufacturing apparatus according to claim 2, wherein the dewatering means comprises a suction box (1) for dewatering the slurry under reduced pressure from the lower surface side of the sheet (4). 4. The raw plate manufacturing apparatus according to claim 2, wherein the dewatering means comprises a support plate (60) having a water absorption hole (61) for supporting the sheet (4) from below. 5. The raw plate manufacturing apparatus according to claim 2, wherein a pressurizing means (62) for pressurizing the inside of the hopper (7) is provided.