JP4939672B2 - Gypsum slurry agitator and gypsum slurry density control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gypsum slurry stirrer and a stirring method, and more particularly to a gypsum slurry stirrer and a stirring method capable of controlling slurry density by controlling operation.
[0002]
[Prior art]
  A gypsum board in which a gypsum-based core material is coated with a base paper for gypsum board is widely used as a building interior material. In general, the gypsum board manufacturing process involves kneading gypsum board materials such as calcined gypsum, adhesion aid, curing accelerator, foam (foam for reducing the weight of gypsum board core), additives and admixtures with water. A process, a slurry pouring process in which the gypsum slurry (slurry) obtained in the kneading process is poured between upper and lower gypsum board base sheets, a molding process in which a molding machine is molded into a plate having a predetermined shape, and a band shape after molding Roughly cut the gypsum board raw material, forcibly dry the raw board after rough cutting, and finally the plate after dryingTargetIt is generally composed of a cutting process for cutting to a proper product size. Other than such general-purpose gypsum board, as a board building material manufactured by the same manufacturing method, lath board, decorative gypsum board, sizing gypsum board, reinforced gypsum board, etc. are known, and these board building materials are used and functioned. As a board building material of various varieties according to JIS standard (JIS A6901), it is actually distributed in the building materials market.
[0003]
As a mixing stirrer for kneading the gypsum board raw material, a thin pin type mixer is used in many gypsum board manufacturing factories. Generally, this type of mixer includes a flat cylindrical housing (housing) that forms a kneading region, and a rotating disk that rotates within the housing by the operation of a rotary drive device. A lower pin (moving pin) is fixed to the upper surface of the rotating disk, and an upper pin (stationary pin) is fixed to the upper lid or upper plate of the housing. The upper and lower pins are alternately arranged in the radial direction of the disk, move relative to each other when the disk rotates, and mix and stir the gypsum board raw material introduced into the housing. The rotating disk extrudes the calcined gypsum slurry after the kneading to the slurry delivery port and supplies it to the subsequent slurry pouring step. Such pin-type mixers are disclosed in, for example, JP-A-8-25342 (Patent Document 1), JP-A 2000-262882 (Patent Document 2), JP-A 2000-6137 (Patent Document 3), and the like. It is disclosed.
[0004]
Here, in the manufacturing process of gypsum board, the raw material of the gypsum board after rough cutting, i.e., green board, is introduced into the dryer for forced drying, but when the dry state of the green board occurs in the dryer, The side green portion (edge portion) tends to be excessively dehydrated, and such an overdrying phenomenon of the side edge portion is generally called “ear burn”. Since the side edges of gypsum boards that have been "ear-burned" tend to be reduced in toughness and become brittle, when fixing gypsum boards to walls with fasteners (screws, etc.) at the construction site, There is a concern that it is difficult to fix the gypsum board to the wall surface due to its weakness, and the side edges of the `` ear burnt '' gypsum board are likely to swell or float, etc. This results in additional on-site work such as repairs such as putty processing and particularly careful paint finishing.
[0005]
In order to avoid such a problem, a slurry stirrer (generally referred to as a “hard edge mixer”) that separates a part of the slurry from the pin-type mixer (main mixer) and re-stirs the pin is used. Used with mold mixers. The slurry stirrer re-stirs a part of the slurry obtained by the main mixer to break up and defoam bubbles in the slurry, and pours the high-density slurry into the zone between the base paper corresponding to the side edges of the gypsum board . For this reason, the side edge part of a gypsum board is formed with a high-density and high-strength gypsum core material, and the problem of the above-mentioned earburn can be avoided beforehand. Such a slurry stirrer is disclosed in, for example, US Pat. No. 4,279,673 (Patent Document 4), US Pat. No. 4,354,885 (Patent Document 5), and the like.
[0006]
FIG. 12 is a longitudinal sectional view and a transverse sectional view showing the internal structure of a conventional slurry stirrer.
The gypsum slurry agitator 100 includes a plurality of rotating blades 110 disposed in a cylindrical housing 101. The rotary blade 110 extends generally outward in the radial direction from a boss portion 102 disposed at the center of the housing 101. The boss portion 102 is fixed to the end portion of the rotation drive shaft 103, and the rotation drive shaft 103 rotates in the rotation direction R by a driving force of a driving device (not shown). The calcined gypsum slurry collected from the main mixer is introduced into the stirrer 100 through the sorting path 105, stirred in the machine by the rotary motion of the rotary blade 110, and then sent to the high-density slurry supply path 106. The paper is supplied from the discharge port of the supply path 106 onto the gypsum board base paper (lower paper).
[0007]
[Patent Document 1]
JP-A-8-25342
[Patent Document 2]
JP 2000-262882 A
[Patent Document 3]
JP 2000-6137 A
[Patent Document 4]
U.S. Pat. No. 4,279,673
[Patent Document 5]
US Pat. No. 4,354,885
[0008]
[Problems to be solved by the invention]
However, in the gypsum slurry supply system provided with such a mixing stirrer and a gypsum slurry stirrer, bubbles added to the mixing stirrer to reduce the weight of the gypsum board core are excessively mixed into the slurry in the mixing stirrer. Or the density of the gypsum slurry supplied from the mixing stirrer to the gypsum slurry stirrer may fluctuate greatly. Since this gypsum slurry is further densified by the bubble breaking and defoaming action of the slurry stirrer, the slurry discharged from the slurry stirrer has an average higher density than the slurry supplied into the mixing stirrer. However, coupled with the change in the slurry density due to the change in the amount of bubbles mixed, a considerable density fluctuation occurs in the slurry. As a result, the density of the gypsum slurry discharged from the slurry stirrer may show a value outside the predetermined range. .
[0009]
When gypsum slurry with a higher density than the specified range is supplied to the edge of the base paper for gypsum board, the edge of the gypsum board product becomes extremely hard, causing so-called `` interface cracks '', and at the construction site This is not desirable because it causes so-called “core cracks” when nails, screws, etc. are driven into the gypsum board. Conversely, when the slurry density falls below the above range, this is due to the “ear burn” phenomenon described above. This is not desirable because it may cause
[0010]
Moreover, the gypsum slurry in the mixing stirrer adheres to the inner wall surface of the mixing stirrer, the surface of the rotating disk, the pin surface, and the like. The gypsum slurry adhering to the inside of the machine begins to harden within a short time, and is gradually laminated on the inner wall surface of the machine to form a hardened lump. The hardened lump generated in the mixing stirrer may be peeled off from the inner wall surface or the surface of the rotating disk by vibration of the mixing stirrer itself, and supplied to the slurry stirrer in a state of being mixed in the slurry. Moreover, the slurry adheres to and cures on the surface of the rotating blades in the slurry stirrer to form a hardened lump, and this hardened lump is also separated from the rotating blade and the like by vibration of the slurry stirrer and the like. Such a hardened lump is hardly crushed in the slurry stirrer and is discharged together with the slurry onto the base paper for gypsum board. When this type of hardened mass passes through the molding machine together with the gypsum board base paper and enters the core part of the gypsum board product, the product part mixed with the hardened mass often has dents or depressions on its surface, When such a hardened mass cannot pass through the molding machine, the base paper for gypsum board is cut, and the production line may be forced to stop.
[0011]
Under such circumstances, it was necessary to variably control the density of the gypsum slurry supplied to the edge of the gypsum board within a predetermined range and to effectively crush the hardened lump. With regard to the conventional slurry stirrer, it has been necessary to depend on the adjustment of the amount of foam added to the slurry stirrer or the adjustment of the amount of foam added to the gypsum slurry supplied to the slurry stirrer.
[0012]
However, since the foam supplied to the slurry stirrer is mixed in the slurry, the foam is broken and defoamed by the stirring action of the slurry stirrer, and then supplied from the slurry stirrer onto the gypsum board base paper. It is very difficult to predict the slurry density on the gypsum board base paper in consideration of the density change of itself and the bubble breaking and defoaming action in the slurry agitator. For this reason, in order to adjust the gypsum slurry within the desired density range, there is no choice but to repeatedly adjust the amount of foam added by trial and error, and it is extremely difficult to control the slurry density reliably and regularly. It was.
[0013]
Moreover, in the method of controlling the slurry density by adjusting the amount of foam added, the amount of foam supplied to the slurry agitator is reduced or the foam supply is stopped in order to increase the slurry density on the slurry agitator outlet side. The slurry adheres to the foam supply port of a slurry stirrer and hardens, resulting in a problem that the foam supply port is blocked. Conversely, if the amount of foam supplied to the slurry stirrer is increased in order to reduce the slurry density on the outlet side of the slurry stirrer, a relatively large amount of foam mixed in the slurry will be subjected to the stirring action to cause bubble breakage / desorption. Since it foams and separates from the slurry in a relatively large amount, different fluids of the slurry phase and the separated air phase are simultaneously discharged onto the gypsum board base paper, and therefore the slurry is irregularly and unstablely discharged onto the gypsum board base paper. The so-called “breathing phenomenon” and sudden fluctuations in the discharge amount occur, making it difficult to supply a stable slurry onto the gypsum board base paper itself.
[0014]
This invention is made | formed in view of such a subject, The place made into the objective is to provide the gypsum slurry stirrer which can control a slurry density by the operation control of a gypsum slurry stirrer. .
[0015]
Another object of the present invention is to provide a gypsum slurry stirrer that prevents a breathing phenomenon and a sudden change in the discharge amount, and enables stable slurry supply onto a gypsum board base paper.
[0016]
Another object of the present invention is to provide a gypsum slurry stirrer that can promote the disappearance of the slurry hardened mass.
[0017]
[Means and Actions for Solving the Problems]
  As a result of intensive studies to achieve the above object, the present inventor formed an inter-blade region occupying element at least partially occupying the region between the rotary blades, and changed the rotational speed of the rotor. The present inventors have found that a slurry can be stably supplied and based on this finding, the present invention has been achieved. That is, the present invention
  A cylindrical housing that forms a stirring region for gypsum slurry, a slurry inlet for introducing gypsum slurry into the stirring region, a slurry outlet for sending gypsum slurry from the stirring region, and a rotatable housing in the housing. In the gypsum slurry stirrer provided with the rotor and the rotational drive shaft for rotationally driving the rotor,
  The rotor includes a plurality of rotating blades extending outward from the rotor central portion, and an inter-blade region occupying element extending outward from the rotor central portion and partially occupying a region between the rotating blades, The inter-blade region occupying element is connected to the rotary blades located on the front side and the rear side in the rotation direction and integrated with the rotary blades.Have,
  The rotary blade forms a narrow stirring region between the rotary blade and the slurry inlet and the housing to pulverize the slurry hardened lump that has flowed into the housing together with the gypsum slurry,
The inter-blade region occupying element reduces the effective volume ratio of the stirring region in the housing to 30 to 65%.A gypsum slurry stirrer is provided.
[0018]
  According to the above configuration of the present invention, the inter-blade region occupying element partially occupies the region between the rotary blades, and the volume ratio of the region in the stirrer that effectively acts as the stirring region, that is, the effectiveness of the gypsum slurry stirrer Decrease in floor area ratioTo do. thisIn such a gypsum slurry agitator, in a wide range of rotation speeds, for example, in the range of 1000 rpm to 2000 rpm, the variation in the discharge amount due to the change in the rotor rotation speed is relatively small, and the gypsum slurry agitator is It has been found that the density of the discharged gypsum slurry increases with increasing rotor speed. Therefore, according to the above configuration of the present invention, the slurry density can be controlled by controlling the rotational speed of the gypsum slurry stirrer.
[0019]
  Also, between the rotating bladesInter-blade area occupation elementAccording to the gypsum slurry stirrer having the above-described configuration, the residence time of the gypsum slurry is shortened and the stirring energy acting on the gypsum slurry is reduced. Fluctuation of the discharge amount hardly occurs, and the gypsum slurry after stirring can be stably supplied onto the gypsum board base paper.
[0020]
  Furthermore, in the gypsum slurry stirrer, the inter-blade region occupying element partially occupies the region between the rotary blades, so that the slurry hardening mass that has flowed into the gypsum slurry stirrer is formed between the rotary vane and the housing. In the relatively narrow stirring region, the pulverization is positively pulverized, and it collides with the front surface of the rotating blade in the rotational direction and is pulverized. For this reason, the disappearance of the slurry hardened mass that has flowed into the gypsum slurry stirrer is promoted in the gypsum slurry stirrer.
  From another point of view, the present invention relates to a gypsum slurry separated from a mixing stirrer so as to supply a density-adjusted gypsum slurry to a predetermined portion on a gypsum board base paperRe-stir to break or defoamIn the density control method of gypsum slurry using a gypsum slurry stirrer,
  As the gypsum slurry stirrer, a plurality of rotating blades extending outward from the center of a rotor rotatably disposed in a housing forming the stirring region of the gypsum slurry, and a region between the rotating blades are partially Gypsum slurry agitator with inter-blade area occupying elementThe effective volume ratio of the stirring region in the housing is reduced to 30 to 65% by the inter-blade region occupying element to shorten the residence time of the gypsum slurry in the housing, and A gypsum slurry stirrer for crushing the hardened slurry lump that flows into the housing together with the gypsum slurry by a narrow agitation region formed between the slurry inlet and the housingUse
  A gypsum slurry density control method is characterized in that the density of the gypsum slurry to be supplied from the gypsum slurry stirrer onto the base paper of the gypsum board is variably controlled by controlling the rotational speed of the rotor of the gypsum slurry stirrer. .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
  According to a preferred embodiment of the present invention, the height (h) of the inter-blade region occupying element decreases continuously or stepwise as it moves backward in the rotational direction. Both the height (h) and the diameter (r) of the inter-blade region occupying element may be set so as to gradually decrease as they transition backward in the rotation direction. Preferably, the height (h) and the diameter (r) of the inter-blade region occupying element are the maximum values (h1) at the connecting portion (42b) between the inter-blade region occupying element and the rotary blade located on the front side in the rotation direction. r1), and is set to indicate the minimum value (h2: r2) at the joint (49a) between the rotary blade and the inter-blade region occupying element located on the rear side in the rotational direction.
[0022]
  In a preferred embodiment of the present invention, the inter-blade region occupying element includes an inclined surface (46) that reduces the height (h) and the diameter (r) in proportion to the rearward transition in the rotational direction, and the inclined surface connected to the inclined surface (46). And a flat surface (47) in which the height (h) and the diameter (r) are set to constant values (h2: r2). Preferably, in the central connection portion (41a) where the center portion and the inter-blade region occupying element are connected, the height (h3) of the inter-blade region occupying element is greater than the minimum value (h2), and the inter-blade region occupancy The height (h) of the element decreases towards the outer radial direction of the rotor. The height (h) of the inter-blade region occupying element transitions radially outward.InYou may set so that it may decrease gradually.
[0023]
  In a preferred embodiment of the present invention, a slurry inlet for introducing gypsum slurry into the cylindrical housing is disposed on the annular outer wall and / or the cover plate of the housing. Preferably, the distance between the downstream end of the slurry inlet and the upper surface (42d) of the rotary blade is set to a value in the range of 0.5 to 3 mm, more preferably 1 to 2 mm. Also preferably,Inter-blade area occupation elementThe ratio of the minimum value of height (h2) / the height of the in-housing region (H) is set to a value in the range of 0.5 to 0.95.
[0024]
In a preferred embodiment of the present invention, the gypsum slurry stirrer of the present invention uses the gypsum slurry stirrer to separate the gypsum slurry separated from the mixing stirrer so as to supply the density-adjusted gypsum slurry to a predetermined portion on the base paper of the gypsum board. Used in the gypsum slurry stirring method to re-stir. The density of the gypsum slurry supplied from the gypsum slurry stirrer onto the gypsum board base paper is controlled by controlling the rotor speed of the gypsum slurry stirrer.
[0025]
Preferably, the control system of the gypsum slurry stirrer includes a rotation speed setting means capable of variably setting the rotor rotation speed, and a rotation speed control means for controlling the rotor rotation speed. The rotation speed control means increases or decreases the rotor rotation speed based on the rotation speed set by the rotation speed setting means. The set value of the rotation speed control means corresponds to the target value of the slurry density. When the slurry density is increased (that is, when a slurry having a higher specific gravity is supplied onto the gypsum board base paper), the rotor rotational speed may be increased by the rotational speed setting means. If desired, a function of the density of the gypsum slurry and the number of rotations of the rotor is defined in advance, and a proportionality constant adapted to the manufacturing conditions is set in advance.
[0026]
【Example】
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG.1 and FIG.2 is the side view and top view which show schematically the structure of a gypsum board manufacturing apparatus.
[0027]
The base paper for the surface of the gypsum board is supplied as the lower paper 1 to the conveyance line 7 of the gypsum board manufacturing apparatus and travels on the conveyance line 3 in the conveyance direction (arrow direction). A roll coater 17 is disposed in the conveyance path of the lower paper 1. A part of the gypsum slurry of the mixing stirrer 4 is introduced into the slurry stirrer 15 via the slurry collecting pipe, and the high specific gravity slurry discharge pipe of the slurry stirrer 15 is relatively high in the specific gravity upstream of the roll coater 17. The gypsum slurry S ′ is fed onto the lower paper 1. The roll coater 17 forms a thin layer (shown by a broken line) of the gypsum slurry S ′ on the upper surface of the lower paper 1.
[0028]
As shown in FIG. 2, the left and right scores are engraved on the lower paper 1 by scoring devices 9a and 9b, and the side edges of the lower paper 1 are folded back by the left and right guide members 8a and 8b. While moving in the transport direction on the transport table 7a, the shape of the edge part of the gypsum board is formed. A mixing stirrer 4 composed of a pin-type mixer is disposed above the transport line 3, and a pair of left and right slurry stirrers 10 are disposed on both sides of the transport line. As shown in FIG. 1, powder raw materials such as calcined gypsum, adhesives, additives, admixtures, bubbles, and liquid raw materials (kneading water and the like) are supplied to the mixing agitator 4. The mixing agitator 4 rotates and drives an internal rotor (not shown) by the rotation of the drive shaft 4a, and mixes and agitates these powder, foam and liquid raw materials, and sends them to the slurry discharge pipe 5 as gypsum slurry S1. Then, the gypsum slurry S1 is discharged from the discharge port 5a of the slurry discharge pipe 5 to the center of the lower paper 1. The mixing stirrer 4 has, for example, the configuration described in Japanese Patent Application Laid-Open No. 8-25342, Japanese Patent Application Laid-Open No. 2000-262882, Japanese Patent Application Laid-Open No. 2000-6137, and the like related to the applicant's application, By quoting these publications, a detailed description of the internal structure of the mixing agitator 4 is omitted.
[0029]
A part of the gypsum slurry of the mixing stirrer 4 is introduced into the left and right slurry stirrers 10 via the slurry sorting pipes 11 and re-stirred by the slurry stirrer 10. The slurry stirrer 10 constitutes a hard edge mixer that supplies a high-density slurry to the side zone of the lower paper 1 corresponding to the edge portion of the gypsum board. The slurry densified by the defoaming / defoaming action of the slurry agitator 10 is sent to the high-density slurry supply pipe 12 as a high-density slurry S2, and is sent from the discharge port 12a to each edge (edge part) of the lower paper 1. Discharge. The gypsum slurry S (S1: S2) supplied from the supply pipes 5 and 12 onto the lower paper 1 travels on the transport line together with the lower paper 1 and reaches the molding machine 6 provided with a pair of upper and lower forming rollers. .
[0030]
The base paper for the back side of the gypsum board is supplied to the conveying line 7 as the upper paper 2. The upper paper 2 is continuously supplied to the forming roller of the forming machine 6 along a predetermined path by the guide of the turning roller. The forming roller turns the upper paper 2 in the conveying direction and stacks it on the gypsum slurry S. A roll coater 18 similar to the roll coater 17 is disposed in the supply path of the upper paper 2. A part of the gypsum slurry of the mixing stirrer 4 is introduced into the slurry stirrer 16 via the slurry sorting pipe, and the high density slurry discharge pipe of the slurry stirrer 16 is relatively high in the upstream side of the roll coater 18. The gypsum slurry S ″ is supplied onto the upper paper 2. The roll coater 18 forms a thin layer (shown by a broken line) of the high-density slurry S ″ on the upper surface of the upper paper 2 in the same manner as the roll coater 17 described above. Since roll coaters of the type such as roll coaters 17 and 18 are disclosed in Japanese Patent Application Laid-Open No. 8-112808 relating to the application of the present applicant, further detailed explanation is given by citing the same publication. Omitted.
[0031]
The lower paper 1, the slurry S, and the upper paper 2 are formed into a continuous laminated body having a three-layer structure and a belt shape by a molding machine 6, and the conveying belt 7b constituting the conveying line 7 is directed to a rough cutting machine (not shown). And the curing reaction of the slurry S proceeds at the same time. A rough cutting machine (not shown) is arranged on the transport line, and the continuous laminate is cut into a predetermined length plate (raw board) by the rough cutting machine. The raw plate after rough cutting is turned upside down by a reversing device (not shown), introduced into a dryer (not shown), forcedly dried in the dryer, and then in a cutting step (not shown). It is cut into a predetermined product length and carried out as a gypsum board product.
[0032]
FIG. 3 is a longitudinal sectional view and a transverse sectional view showing the internal structure of the slurry agitator 10, and FIGS. 4, 5 and 6 are plan views showing the structure of a rotor disposed in the slurry agitator 10. It is a side view, a bottom view, a cross-sectional view taken along line II, and a perspective view. Note that the roll coater slurry agitators 15 and 16 also have substantially the same structure as the slurry agitator 10 described below.
[0033]
As shown in FIG. 3, the slurry agitator 10 has a flat cylindrical housing (housing) 20, and the housing 20 has a horizontal disk-shaped upper plate (upper lid) 22 and a lower portion that are spaced apart from each other. A plate (bottom lid) 24 and an annular outer peripheral wall 23 connected to the outer peripheral portions of the upper plate 22 and the lower plate 24 are provided. The downstream end 11a of the slurry sorting tube 11 is connected to the upper plate 22, and the upstream end 12b of the high density slurry supply tube 12 is connected to the outer peripheral wall 23 to form a slurry inlet.
[0034]
A circular opening 21 is formed at the center of the upper plate 22, and an end 31 of the vertical rotating shaft 30 passes through the circular opening 21 and extends into the slurry agitator 10. The rotation shaft 30 is connected to a rotation drive device 33 such as an electric motor via a transmission device 32 such as a transmission gear mechanism or a belt-type transmission. The transmission device 32 and the rotational drive device 33 are connected to the control unit 34 via a control signal line (shown by a broken line). The control unit 34 includes a rotation speed setting unit that can manually set the rotation speed of the rotary shaft 30 and a rotation speed control unit that can variably control the speed ratio of the transmission 32 or the rotation speed of the rotation drive device 33. The rotation speed control means adjusts the speed ratio of the transmission 32 or the rotation speed of the rotation drive device 33 based on a target value (slurry density target value or rotation speed target value) manually set by the operator in the rotation speed setting means. The rotational speed of the rotary shaft 30 is controlled to the target rotational speed.
[0035]
  A metal rotor 40 in which the boss portion 41, the rotating blade 42 and the flipper portion 43 are integrated is disposed in the housing 20 so as to be rotatable. The boss portion 41 is disposed at the center of the rotor 40.The flipper portion 43 constitutes an inter-blade region occupying element that extends outward from the rotor center portion (boss portion 41) and partially occupies the region between the rotary blades 42.A boss hole 44 into which the rotary shaft 30 can be fitted is formed in the center of the boss portion 41. The central axes of the housing 20, the rotating shaft 30, and the rotor 40 coincide. The rotor 40 rotates in the rotation direction R around the central axis XX of the slurry agitator 10 by the rotation of the rotating shaft 30.
[0036]
The boss part 41 has a substantially square planar form, and the rotating blades 42 extend in the radial direction of the rotor 40 from each corner of the boss part 41 to the vicinity of the outer peripheral wall 23. The flipper portion 43 extends rearward in the rotational direction of each rotary blade 42 and reaches the front surface 42 a in the rotational direction of the rear rotary blade 42. The rotary blades 42 and the flipper portion 43 have a point-symmetric structure with respect to the center point of the rotor 40, and the rotary blades 42 are arranged at an angular interval of 90 degrees. The distance t between the upper surface 42d of the rotary blade and the downstream end (slurry inlet) 11a of the slurry sorting tube 11 is set in a range of 1 to 2 mm.
[0037]
The structure of the rotary blade 42 and the flipper portion 43 will be described in more detail with reference to FIGS.
The rotary vane 42 has a vertical flat plate shape extending radially outward from the central axis XX of the rotor 40. The flipper portion 43 extending between the rotary blades 42 is connected to the upper inclined surface 46 that extends rearward in the rotational direction from the upper edge 42b of the rotary blade 42 and the rear end 46a of the inclined surface 46, and rotates rearward in the rotational direction. A flat surface 47 extending horizontally to the blades 42, an outer inclined surface 48 extending rearward in the rotational direction from the outer end edge 42c of the rotary blade 42, and a curved surface extending rearward from the rear end 48a of the inclined surface 48 49. The upper inclined surface 46 is inclined downward with an angle α with respect to the upper surface of the rotary blade 42, and the outer inclined surface 48 is radially inward with an angle β with respect to the outer end surface 42 e of the rotary blade 42. Tilt. The angles α and β are set to an angle in the range of 5 to 45 degrees, for example. The curved surface 49 is a circumferential surface having a radius r2 centered on the central axis XX, and the rear end 49a of the curved surface 49 connected to the rotational direction front surface 42a of the rotary blade 42 is from the outer end surface of the rotary blade 42. It is located radially inward by a distance s. The ratio of radius r2: distance s is set within a range of 10: 1 to 2: 1, for example. As shown in FIG. 5B, the height h3 of the inclined surface 46 is greater than the height h2 of the flat surface 47 in the connecting portion 41a between the boss portion 41 and the inclined surface 46. The ratio of the height H (FIG. 3): height h2 of the region in the housing 20 is set to a value in the range of 1: 0.75 to 0.90.
[0038]
As shown in FIG. 3, the flipper portion 43 occupies the central region of the region between the rotary blades 42, and the stirring region is formed between the rotor 40, the outer peripheral wall 23, and the upper plate 22. The slurry in the slurry agitator 10 stays in the central area and tends to adhere to the inside of the machine and form a cured slurry lump. However, since the flipper portion 43 occupies this area, slurry retention hardly occurs. The slurry cured mass is difficult to produce.
[0039]
Further, the inclined surfaces 46 and 48 have a form in which the flat surface 47 and the curved surface 49 are enlarged forward in the rotational direction, and the rear surface of the rotary blade 42 to which the slurry easily adheres is completely removed from the stirring region by the flipper portion 43. Hidden.
[0040]
The calcined gypsum slurry of the mixing stirrer 10 introduced into the slurry stirrer 10 is re-stirred by the rotation of the rotor 40, the bubbles in the slurry are destroyed, and the specific gravity of the slurry increases. The portion where the slurry stays or the slurry lump easily adheres is occupied by the flipper 40, and the flipper 40 forms a narrow region between the lower surface of the upper plate 22 and the inner wall of the outer peripheral wall 23. However, the slurry is appropriately re-stirred because it has a form that prevents unnecessary retention of the slurry, and the specific gravity of the slurry increases due to the bubble-breaking effect or the de-foaming effect by re-stirring. The slurry hardened lump or scale that has flowed into the slurry agitator 10 together with the calcined gypsum slurry of the mixing agitator 4 is crushed by the rotation of the rotary blade 42. This is a phenomenon in which the soot or scale is actively crushed in a narrow gap (spacing t) between the upper surface 42d of the rotary blade and the downstream end (slurry inlet) 11a of the slurry sorting tube 11, and the flipper section This is considered to be due to a phenomenon in which the wrinkles or scales on 40 collide with the front surface 42a in the rotational direction of the rotary blade 42 and are crushed.
[0041]
According to the experiments by the present inventor, the slurry agitator 10 stably discharges a high specific gravity slurry in a wide range of rotation speed, and the breathing phenomenon of the discharged slurry due to excessive separation of the slurry entrained air hardly occurs. It has been found that the density (specific gravity) of the high specific gravity slurry discharged by the slurry agitator 10 gradually increases in accordance with the increase in the rotor rotational speed (RPM).
[0042]
FIG. 7A is a chart showing test results of a comparative test using the slurry stirrer 10 having the above-described configuration and the slurry stirrer 100 having the conventional structure shown in FIG. 12, and FIG. It is a diagram which shows the relationship between the rotor rotation speed and slurry density in a stirrer.
[0043]
The test was conducted to investigate the fluctuation of the slurry density and the bubble volume ratio of the high specific gravity slurry discharged from the slurry agitator 10, 100. In the test, the calcined gypsum slurry prepared in advance was supplied to the slurry agitators 10 and 100 at a constant supply rate (80 ml / min), and the high specific gravity slurry flowing out from the discharge port of the slurry agitators 10 and 100 was supplied with a 255 ml paper cup. The slurry that has risen from the upper surface of the paper cup is removed with a stainless scale without filling the slurry in the paper cup by vibration or the like, and the slurry weight in the paper cup is measured, and the slurry density (g / cm^Three) And bubble volume ratio (% by volume). The volume ratio of bubbles was calculated by dividing the total volume of gypsum, liquid, admixture, additives, etc. in the slurry (that is, the total volume of raw materials (including water) blended during slurry preparation) by the volume of the paper cup (255 ml). Value. The slurry stirrer 100 shown in FIG. 12 is of a three-blade type provided with three rotary blades 110. In the test, a slurry of a four-blade type provided with four rotary blades 110 was used. A stirrer was used.
[0044]
The slurry density and the bubble volume ratio of the calcined gypsum slurry prepared before being supplied to the slurry agitator 10, 100 are as follows.
Slurry density: 1.03 g / cm^Three
Bubble volume ratio: 44%
[0045]
Change the number of revolutions (RPM) of the slurry agitator 10, 100 in the range of 1000 to 2000 R.PM, and measure the slurry density and bubble volume ratio of the high specific gravity slurry discharged by the slurry agitator 10, 100 at each revolution number. did. The measurement results are as shown in FIG.
[0046]
As shown in FIG. 7 (A), the high specific gravity slurry discharged by the slurry agitator 10 has a small change rate of slurry density and bubble volume ratio compared to the number of revolutions changing in the range of 1000 to 2000 R.PM. The slurry agitator 10 smoothly discharged the high specific gravity slurry without causing a breathing phenomenon at each rotation speed.
[0047]
On the other hand, in the slurry stirrer 100 having a conventional structure, the slurry density and the bubble volume ratio change relatively greatly at the rotation speeds of 1200 R.PM and 1500 R.PM, and at the rotation speeds of 1700 R.PM and 2000 R.PM. The slurry was discharged while the air separated from the slurry was taken in, and a breathing phenomenon occurred. As a result, the high specific gravity slurry could not be uniformly filled in the paper cup, making measurement impossible.
[0048]
As is clear from these test results, the slurry agitator 10 stably discharges the high specific gravity slurry in a relatively wide range of rotation speeds, and the slurry density increases as the rotor rotation speed increases, and the bubbles The volume ratio decreases.
[0049]
As shown in FIG. 7B, the slurry density has a general correlation with the rotational speed of the slurry agitator 10 as shown in the following equation.
Y = η · X + δ
Y: Slurry density (g / cm^Three )
X: Number of revolutions (R.P.M)
η, δ: Constant
[0050]
In this example, the constant η is about 0.0001 and the constant δ is about 1.03.
Therefore, according to the slurry agitator 10 of the present embodiment, since the slurry density has the above relationship with the rotor rotational speed, the slurry density can be controlled by setting the rotor rotational speed.
[0051]
As described above, according to the slurry agitator 10 according to the above-described embodiment, the rotor 40 includes the flipper portion 43 that is integrated with the rotor central portion and the rotating blades 42 and partially occupies the region between the rotating blades 42. The height (h) of the flipper portion 43 decreases as it transitions backward in the rotational direction, and the diameter (r) of the flipper portion 43 decreases as it transitions backward in the rotational direction and radially outward. Since the flipper portion 43 occupies the central region between the rotating blades where the slurry tends to stay, the slurry stays hardly, the hardened slurry lump hardly adheres to the rotor 40, and the slurry agitator 10 operates stably over a long period of time. can do.
[0052]
In addition, the slurry hardened lump or scale that has flowed into the slurry stirrer 10 together with the calcined gypsum slurry of the mixing stirrer 4 is crushed by the rotation of the rotary blade 42, so that the disappearance of the slurry hardened lump is prevented by stirring the gypsum slurry. It can be promoted in the machine 10.
[0053]
Furthermore, in the slurry stirrer having the above configuration, the specific correlation as described above is established between the rotor rotational speed and the slurry density, so that the slurry density can be controlled by controlling the rotational speed of the rotor 40.
[0054]
FIG. 8 is a plan view and a partial cross-sectional view of the rotor 40 showing a modification of the rotary blade 42. 8, FIG. 8B is a cross-sectional view taken along the line II-II in FIG.
[0055]
In the above-described embodiment, the rotary blade 42 is described as having a vertical plate-like cross-sectional shape as shown in FIG. 8B, but a curved shape or a semicircular cross-section bulging forward in the rotational direction (FIG. 8). (C) Alternatively, it may be formed in the form of a triangular cross section (FIG. 8D), or a parallelogram cross section (FIGS. 8E and 8F) inclined forward or backward in the rotational direction. You may form in.
[0056]
FIG. 9 is a side view of the rotor 40 showing a modification of the flipper 43, and FIG. 10 is a plan view of the rotor 40 showing a modification of the rotary blade 42. As shown in FIG. FIG. 11 is a plan view and a side view of the rotor 40 showing a modification of the flipper portion 43 and the rotary blade 42. As shown in each figure, the form, arrangement, and orientation of the flipper portion 43 and the rotary blade 42 can be arbitrarily changed as long as the flipper portion 43 and the rotary blade 42 exhibit the above-described functions.
[0057]
In the gypsum board manufacturing apparatus, it is necessary to install the slurry stirrer 10 in a relatively narrow space or an irregular space, but the central axis XX of the slurry stirrer 10 is set horizontally depending on the situation of the installation space. For example, the slurry stirrer 10 may be disposed in a lateral direction or may be disposed in a generally inclined state.
[0058]
Further, the slurry agitator 10 has a structure including four rotating blades 42, but may include two or three rotating blades, or five or more rotating blades.
[0059]
Further, in the slurry agitator of the present invention, the rotation direction of the rotor 40 can be set in the direction opposite to the rotation direction R. Even in this case, a relatively large shearing force acts on the gypsum slurry in the slurry agitator between the upper surface of the flipper portion 43 and the upper plate 22.
[0060]
【The invention's effect】
As explained above, according to the gypsum slurry stirrer of the present invention, the slurry density can be controlled by controlling the rotation speed of the gypsum slurry stirrer.
[0061]
Further, according to the gypsum slurry stirrer of the present invention, it is possible to prevent a breathing phenomenon and a sudden change in the discharge amount and stably supply the slurry onto the gypsum board base paper.
[0062]
Furthermore, according to the gypsum slurry stirrer of the present invention, the slurry hardened lump in the gypsum slurry flowing into the slurry stirrer can be crushed in the gypsum slurry stirrer to promote disappearance of the slurry hardened lump.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a configuration of a gypsum board manufacturing apparatus.
FIG. 2 is a plan view schematically showing a configuration of a gypsum board manufacturing apparatus.
FIG. 3 is a longitudinal sectional view and a transverse sectional view showing an internal structure of a slurry stirrer.
FIGS. 4A and 4B are a plan view and a side view showing a structure of a rotor disposed in a slurry agitator. FIGS.
5 is a bottom view and a cross-sectional view taken along the line I-I of the rotor shown in FIG. 4;
6 is a perspective view of the rotor shown in FIG. 4. FIG.
7A is a chart showing test results of a comparative test using the slurry agitator according to the present invention and a slurry agitator having a conventional structure, and FIG. 7B is a slurry agitation. It is a diagram which shows the relationship between the rotation speed in a machine, and slurry density.
FIGS. 8A and 8B are a plan view and a partial cross-sectional view of a rotor showing a modification of a rotary blade.
FIG. 9 is a side view of a rotor showing a modification of the flipper portion.
FIG. 10 is a plan view of a rotor showing a modification of a rotary blade.
FIGS. 11A and 11B are a plan view and a side view of a rotor showing a modification of the flipper portion and the rotating blades. FIGS.
FIG. 12 is a longitudinal sectional view and a transverse sectional view showing an internal structure of a conventional slurry stirrer.
[Explanation of symbols]
10 Slurry stirrer
20 Housing
30 Vertical axis of rotation
40 rotors
41 Boss
42 Rotating blade
43 Flipper
46, 48 inclined surface
47 Flat surface
49 Curved surface
R direction of rotation

Claims (7)

A cylindrical housing that forms a stirring region for gypsum slurry, a slurry inlet for introducing gypsum slurry into the stirring region, a slurry outlet for sending gypsum slurry from the stirring region, and a rotatable housing in the housing. In the gypsum slurry stirrer provided with the rotor and the rotational drive shaft for rotationally driving the rotor,
The rotor includes a plurality of rotating blades extending outward from the rotor central portion, and an inter-blade region occupying element extending outward from the rotor central portion and partially occupying a region between the rotating blades, The inter-blade region occupying element is connected to the rotary blades located on the front side and the rear side in the rotational direction and integrated with the rotary blades,
The rotary blade forms a narrow stirring region between the rotary blade and the slurry inlet and the housing to pulverize the slurry hardened lump that has flowed into the housing together with the gypsum slurry,
The inter-blade area occupying element reduces the effective volume ratio of the stirring area in the housing to 30 to 65% .   2. The gypsum slurry agitator according to claim 1, wherein the radius (r) of the inter-blade region occupying element decreases continuously or stepwise as it moves backward in the rotational direction.   The gypsum slurry stirrer according to claim 1 or 2, wherein the height (h) of the inter-blade region occupying element decreases continuously or stepwise as it transitions backward in the rotational direction.   4. The height (h) of the inter-blade region occupying element decreases continuously or stepwise toward the radially outer side of the rotor. 5. Gypsum slurry stirrer. Density control of gypsum slurry using a gypsum slurry stirrer that re-stirs and defoams the gypsum slurry separated from the mixing stirrer so that the density-adjusted gypsum slurry is supplied to a predetermined part of the gypsum board In the method
As the gypsum slurry stirrer, a plurality of rotating blades extending outward from the center of a rotor rotatably disposed in a housing forming the stirring region of the gypsum slurry, and a region between the rotating blades are partially A gypsum slurry stirrer having an inter-blade region occupying element , wherein the effective volume ratio of the agitating region in the housing is reduced to 30 to 65% by the inter-blade region occupying element, The residence time of the gypsum slurry is shortened and the hardened slurry lump that flows into the housing together with the gypsum slurry is pulverized by a narrow stirring region formed between the rotary blade, the slurry inlet and the housing. Use a gypsum slurry stirrer to
A density control method for a gypsum slurry, wherein the density of the gypsum slurry to be supplied from the gypsum slurry stirrer onto the gypsum board base paper is variably controlled by controlling the rotational speed of the rotor of the gypsum slurry stirrer.   The density of the gypsum slurry is variably controlled using a control system of a gypsum slurry stirrer provided with a rotation speed setting means capable of variably setting the rotation speed of the rotor and a rotation speed control means for controlling the rotation speed. The density control method according to claim 5.   A function of the density of the gypsum slurry and the rotational speed of the rotor is defined in advance, and a proportionality constant suitable for manufacturing conditions is set in advance, and the rotational speed control means is the rotational speed set by the rotational speed setting means. The density control method according to claim 6, wherein the number of rotations of the rotor is increased or decreased based on a number.

Images