JP3475852B2 - Powder coating equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to the surface coating of various powders in the fields of pharmaceuticals, foods, functional ceramics, etc. for the purpose of imparting anticorrosion function, sustained release function and other functions. The present invention relates to a surface coating device for powder and granules suitable for use in.

[0002]

2. Description of the Related Art Conventionally, as a surface coating apparatus of this type, a high-speed fluidized mixing apparatus (Henschel mixer, etc.), a planetary type mixing apparatus (universal stirring mixer, etc.), a fluidized bed granulating apparatus, and a stirring type fluidized bed are mainly used. Four types of granulators are known.

[0003]

FIG. 6 is a schematic cross-sectional view showing an example of a surface coating state by a conventional surface coating apparatus for powder or granular material.

However, in a high-speed fluidized mixing device or a planetary type mixing device, when powder and granules and a modifying liquid are charged and surface coating is performed under a heating and depressurizing environment, the modifying liquid becomes Due to the surface tension, a large amount is concentrated in the concave portions on the surface of the granular material 14, and the thickness of the coating layer 23 made of the solid component of the modifying liquid becomes uneven, so that the original function of the coating (corrosion prevention function, etc.) is fully exerted. In addition to this, there is a problem that it is not suitable for the fragile powder particles 14 because a large shearing force acts on the powder particles 14 during the work.

On the other hand, in the fluidized bed granulator, the spray nozzle for spraying the modifying liquid is arranged above, and the powder granules 14
Since the modifying liquid is sprayed on the upper part of the fluidized layer, it becomes difficult to make the thickness of the coating layer 23 uniform unless the powder particles 14 that are floating and flowing do not convection. Further, since the modifier liquid is dried while it reaches the powdery or granular material 14 from the spray nozzle, there is a possibility that a spray dust phenomenon may occur which causes the modifier liquid to dry before being adhered, and the coating efficiency may be reduced. Therefore, by lowering the solid component ratio of the modifying liquid to increase the latent heat of vaporization, the time that can be modified is extended.
There was the inconvenience of being forced to take some measure against spray dust.

On the other hand, in the stirring type fluidized bed granulator,
Since the modification liquid is sprayed from the spray nozzle attached to the side surface of the floating fluidized bed, the concentration of the powder particles 14 is high in the vicinity of this spray nozzle, and the surface coating can be performed more efficiently than the above fluidized bed granulator. Although it is possible, in order to prevent blocking of the particles 14 with each other by the modifying liquid and maintain a good fluidized state, the drying efficiency must be increased. Since the solid component of the modification liquid is in a spotted state because it is dried at the same time as being adhered, the drawback that the thickness of the coating layer 23 is likely to be non-uniform still remains.

In view of such circumstances, the present invention improves the drying efficiency of the modifying liquid, and at the same time, makes it possible to achieve the full function of the coating by making the thickness of the coating layer uniform. It is an object to provide a body surface coating device.

[0008]

In the present invention, it has been noted that the convection of the granular material can be promoted by guiding the granular material along the reflux eave having a predetermined shape.

That is, the present invention has a cylindrical body (2) having a bottomed cylindrical shape, forms a fluid chamber (9) in the tubular body, and agitates powder particles (14) by rotating in the fluid chamber. A powder stirrer (4) for spraying the modifying liquid into the flow chamber, and a powder formed so as to rise in a circular arc cross section with the peripheral edge of the bottom surface of the cylindrical body facing the side surface. In the surface coating device (1) for granules, a reflux eaves (20) is formed in the upper part of the flow chamber so that its lower surface (20a) is recessed from the side surface of the cylindrical body in a circular arc cross section. By adopting such a configuration, when coating the surface of the granules, the granules receive the stirring force of the stirrer and rotate while expanding in the horizontal plane, and in addition to the vertical direction along the lower surface of the reflux eaves. Since the particles are recirculated in the direction, the particles convection along the spiral ring-shaped path, and the particles act in a uniform manner in the flow chamber.

Further, according to the present invention, there is provided a cylindrical tubular body (2), and a disk-shaped bottom plate (8) is rotatably provided in the tubular body so that a flow chamber (9) is formed on the upper side thereof. A device for spraying a modifying liquid (17) for spraying a modifying liquid is provided in the flow chamber, and a surface coating device for powder particles formed so that the peripheral portion of the bottom plate rises in an arc cross section toward the side surface of the cylindrical body ( In 1), the reflux eaves (20) is formed in the upper part of the flow chamber so that its lower surface (20a) is recessed from the side surface of the cylindrical body in a circular arc cross section. With this configuration, when the surface of the granular material is coated, the granular material receives centrifugal force due to the rotation of the bottom plate and rotates while expanding the diameter in the horizontal plane, and also in the vertical direction along the lower surface of the reflux eaves. Therefore, the powder and granules convect along the spiral ring-shaped path, and act so that the powder and granules are evenly distributed in the flow chamber.

Further, according to the present invention, a ventilation hole (8b) is formed in the bottom plate (8), and an air supply means for supplying flowing air from below to above the bottom plate is provided through the ventilation hole. With such a configuration, the powdery particles can be lifted by the flowing air and suspended in the flowing chamber.

Further, the present invention is constructed by additionally providing a pressure reducing means (13) for lowering the pressure in the flow chamber (9) below atmospheric pressure. With such a configuration, it becomes possible to perform the surface coating of the granular material under a static pressure environment lower than the atmospheric pressure, thereby lowering the vaporization temperature of the solvent of the modification liquid, and drying the granular material and thus the time required for the entire surface coating. Acts so that it can be shortened.

Note that the reference numerals in parentheses are for convenience of representing corresponding elements in the drawings, and therefore, the present invention is not limited to the description in the drawings. This also applies to the "Claims" section.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment> FIG. 1 is a sectional view showing a first embodiment of a surface coating apparatus for powder or granular material according to the present invention, and FIG. 2 shows an agitator for the surface coating apparatus shown in FIG. Is a figure,
(A) is the top view, (b) is an end view by the AB line of (a).

As shown in FIG. 1, the powdery or granular surface coating apparatus 1 has a cylindrical body 2 having a bottomed cylindrical shape, and the bottom peripheral portion of the cylindrical body 2 faces the side surface thereof. It is formed so as to rise in an arc cross section. Further, a flow chamber 9 is formed inside the cylindrical body 2, and a cylindrical temperature control jacket 10 is provided on the outer periphery of the cylindrical body 2.

Further, the cylindrical body 2 is provided with a stirrer 4, and the stirrer 4 is composed of a rotating shaft 5 and two kinds of stirring blades 6 and 7. The rotary shaft 5 is rotatably supported in the center of the bottom surface of the cylindrical body 2 via a bearing 3 in the directions of the arrows M and N about the axial center CT1, and the two types of stirring blades 6 and 7 are shown in FIG. Further, as shown in FIG. 2, they are horizontally attached to the rotary shaft 5 in such a manner that they are vertically arranged in two stages, that is, vertically. The upper stirring blade 6 is composed of two blade main bodies 6a formed in an elongated plate shape,
It is located at the middle height. On the other hand, the lower stirring blade 7
Is provided with a curved portion 7b, which is curved upward in an arc shape, corresponding to the peripheral edge portion of the bottom surface of the cylindrical body 2 at the tips of the two blade main bodies 7a formed in the shape of elongated plates. The side surface is formed with a tapered surface 7c and is located near the bottom surface of the cylindrical body 2.

A plurality of (for example,
The four liquid ejecting means 17 are arranged at predetermined angular intervals (for example, 90).
(Equal angle intervals of °), each of the spray means 1 is attached.
7 is composed of a spray nozzle 18 and a compressed air supplier 19.

On the other hand, a lid 12 is openably and closably attached to the upper opening of the tubular body 2, and a pressure reducing means 13 is connected to the lid 12. The pressure reducing means 13 is composed of an opening / closing valve 15 and a vacuum pump 16.

By the way, a reflux canopy 20 is provided in an upper portion of the flow chamber 9 in the cylindrical body 2. Lower surface 2 of this reflux eaves 20
0a is formed so as to be continuous from the side surface of the cylindrical body 2 in an arc cross section, and the upper surface 20b of the reflux hood 20 is inclined in a conical shape.

The following procedure is used to apply a surface coating to a powder or granular material using the powder or granular material surface coating device 1 having the above-described structure.

First, the tubular body 2 is kept at a predetermined temperature by the temperature control jacket 10, the lid 12 is opened and a predetermined amount of powdery or granular material 14 is put into the tubular body 2, then the lid 12 is closed and the rotary shaft 5 is rotated. Is rotated in the direction of arrow N about its axis CT1. Then, since the stirring blades 6 and 7 rotate with the rotation of the rotating shaft 5, the granular material 14 receives the stirring force and rotates to reach the bottom peripheral portion of the cylindrical body 2 and the side surface of the cylindrical body 2. Ascends along and reaches the reflux eaves 20. Here, since the lower surface 20a of the reflux eaves 20 is continuous from the side surface of the tubular body 2 in an arcuate cross-sectional shape, the lower surface 20a is guided by the lower surface 20a and the powder particles 14 are guided.
Falls near the rotating shaft 5.

After that, by repeating such an operation, the powdery particles 14 convection, and the path of the powdery particles 14 becomes a spiral ring shape. As a result, the particles 14 continue to be convected while being evenly distributed in the flow chamber 9.

In this state, the modifying liquid is sprayed into the cylindrical body 2 by using each of the spray liquid means 17. It has a spray nozzle 1
The modifying liquid is supplied to No. 8, and the compressed air is supplied from the compressed air supplier 19 to the spray nozzle 18. Then,
The modifying liquid is sprayed from the spray nozzle 18 toward the fluid chamber 9 in the cylindrical body 2, and the powdery or granular material 14 convection in the fluid chamber 9 is generated.
Adhere to the surface of. At this time, since the distribution of the powder particles 14 in the flow chamber 9 is uniform, there is almost no individual difference in the amount of the modifying liquid deposited between the powder particles 14 and the entire surface of each powder particle 14 is not affected. The modification liquid is evenly attached to the.

When a predetermined amount of the modifying liquid adheres to the granular material 14 in this way, the spraying of the modifying liquid by the jet liquid means 17 is stopped, and the opening / closing valve 15 of the pressure reducing means 13 is opened to open the vacuum pump 1.
By driving 6, the air in the cylindrical body 2 is discharged and the flow chamber 9 is decompressed. At this time, the stirring blades 6 and 7 continue the rotation operation. Then, the granular material 14 continues convection along the spiral ring-shaped path, and the modification liquid adhering to the surface of the granular material 14 dries, and as shown in FIG. 5, consists of the solid component of the modification liquid. The coating layer 23 is formed. At this time, since the pressure in the flow chamber 9 is lower than the atmospheric pressure, the vaporization temperature of the solvent of the modifying liquid is lowered, and the powdery or granular material 1 is reduced in that time.
Drying of 4 is completed. At this time, the powder 14 is dried with the modifying liquid evenly attached to the surface thereof, so that the coating layer 23 has a uniform thickness even if the surface of the powder 14 has irregularities.

When the drying of the granular material 14 is completed in this way, the surface coating of the granular material 14 is completed, but since the coating layer 23 having a uniform thickness is formed around the granular material 14. , The coating functions (anticorrosion function, sustained release function, etc.) will be fully exerted.

<Second Embodiment> FIG. 3 is a sectional view showing a second embodiment of the surface coating apparatus for powder or granular material according to the present invention, and FIG. 4 is a plan view showing a bottom plate of the surface coating apparatus shown in FIG. It is a figure.

As shown in FIG. 3, the surface coating apparatus 1 for the powdery or granular material has a cylindrical tubular body 2 in which a rotary shaft 5 is mounted via a bearing 3. It is supported so as to be rotatable and driven in the directions of arrows M and N around the axis CT1.
A bottom plate 8 is horizontally fitted to the rotary shaft 5, and the bottom plate 8 is formed such that the peripheral edge portion thereof rises in an arc cross-section toward the side surface of the tubular body 2 as shown in FIGS. 3 and 4. It has a disc-shaped bottom plate body 8a. Four vent holes 8b are formed in a circular arc shape in the bottom plate body 8a, and a wire mesh 8c having a predetermined mesh number is attached to each vent hole 8b. Therefore, the air can pass through the vent hole 8b, but the powdery particles cannot pass through the vent hole 8b.

Further, as shown in FIG. 3, a bracket 21 is attached to the rotary shaft 5 so as to fix the bottom plate 8,
The bracket 21 is provided with a stirring blade 6 horizontally protruding.
A flow chamber 9 is formed above the bottom plate 8.

A plurality of (for example,
The three jetting means 17 are arranged at predetermined angular intervals (for example, 12).
They are attached at equal angular intervals of 0 °), and each of the liquid jet means 17 is composed of a spray nozzle 18 and a compressed air supply device 19.

On the other hand, a hopper 22 is provided at the upper opening of the cylindrical body 2.
Is mounted, and a bag filter (not shown) is attached to the upper part of the hopper 22.

By the way, a reflux eave 20 is provided in the upper part of the flow chamber 9 in the cylindrical body 2. Lower surface 2 of this reflux eaves 20
0a is formed so as to be continuous from the side surface of the cylindrical body 2 in an arc cross section, and the upper surface 20b of the reflux hood 20 is inclined in a conical shape.

When the surface coating of a granular material is performed using the surface coating apparatus 1 for a granular material having the above-described structure, the following procedure is performed.

First, after a predetermined amount of powdery or granular material 14 is put into the cylindrical body 2 from the hopper 22, flowing air is supplied from below the bottom plate 8 to above the bottom plate 8, that is, into the flow chamber 9, and the rotary shaft 5 is rotated. The axis CT1 is rotated in the direction of the arrow N. Then, the powdery particles 14 are lifted and floated in the flow chamber 9 by the flowing air, while the bottom plate 8 and the stirring blades 6 rotate with the rotation of the rotating shaft 5. The granules 14 also reach the peripheral portion of the bottom plate 8 while rotating, rise along the side surface of the cylindrical body 2, and further reach the reflux eaves 20. Here, since the lower surface 20a of the reflux eaves 20 is continuous from the side surface of the cylindrical body 2 in an arcuate cross-sectional shape, the powder particles 14 are guided by the lower surface 20a and fall near the rotary shaft 5.

After that, by repeating such an operation, the powdery particles 14 convection, and the path of the powdery particles 14 becomes a spiral ring shape. As a result, the particles 14 continue to be convected while being evenly distributed in the flow chamber 9.

In this state, the modifying liquid is sprayed into the cylindrical body 2 by using each of the spray liquid means 17. It has a spray nozzle 1
The modifying liquid is supplied to No. 8, and the compressed air is supplied from the compressed air supplier 19 to the spray nozzle 18. Then,
The modifying liquid is sprayed from the spray nozzle 18 toward the fluid chamber 9 in the cylindrical body 2, and the powdery or granular material 14 convection in the fluid chamber 9 is generated.
Adhere to the surface of. At this time, since the distribution of the powder particles 14 in the flow chamber 9 is uniform, there is almost no individual difference in the amount of the modifying liquid deposited between the powder particles 14 and the entire surface of each powder particle 14 is not affected. The modification liquid is evenly attached to the.

When a predetermined amount of the modifying liquid adheres to the powder or granules 14 in this way, the spraying of the modifying liquid by the jet liquid means 17 is stopped, and the rotating operation of the stirring blades 6 and 7 is continued. Then,
The granular material 14 continues convection along the spiral ring-shaped path, the modification liquid adhering to the surface of the granular material 14 dries, and as shown in FIG. 5, a coating layer made of a solid component of the modification liquid. 23
Is formed. At this time, since the powder and granules 14 are dried while the modifying liquid is evenly attached to the surface of the powder and granules 14,
Even if there is unevenness on the surface, the thickness of the coating layer 23 becomes uniform.

When the drying of the granular material 14 is completed in this way, the surface coating of the granular material 14 is completed. Since the coating layer 23 having a uniform thickness is formed around the granular material 14. , The coating functions (anticorrosion function, sustained release function, etc.) will be fully exerted.

[0039]

EXAMPLES Examples of the present invention will be described below.

<Example 1> Using the surface coating apparatus for powder and granules described in the first embodiment, toluene and methyl ethyl ketone were added to spherical powder and granules made of magnetite (magnetite) having a diameter of about 50 to 100 μm. A modification liquid in which an acrylic resin was dissolved was sprayed onto the mixed solvent of to coat the surface.

<Comparative Example 1> The same procedure as in Example 1 was repeated except that the conventional high-speed fluidizing and mixing apparatus was used instead of the surface coating apparatus for the granular material described in the first embodiment. Surface coating was performed.

<Observation of Covering State> FIG. 5 is a schematic sectional view showing an example of the surface coating state of the powdery surface coating apparatus according to the present invention.

Observation of the two types of powder particles thus surface-coated with a backscattered electron image revealed that, in the powder particles of Example 1, as shown in FIG. 14
While it became uniform regardless of the presence or absence of surface irregularities,
In the granular material of Comparative Example 1, as shown in FIG.
A large amount of the solid component of the modifying liquid is concentrated in the recesses on the surface, and the coating layer 2
3 became non-uniform in thickness.

<Measurement of coating amount> The carbon amount of these two types of powder and granules was measured by a carbon-sulfur analyzer, and it was found to be 1.2% by weight in the powder and granules of Example 1. On the other hand, in the case of the granular material of Comparative Example 1, the content was 0.57% by weight (that is, a little less than half the carbon content of Example 1). This is a result of supporting that the solid component (acrylic resin) of the modifying liquid is attached in a larger amount in the powder of Example 1 than in the powder of Comparative Example 1.

[0045]

As described above, according to the invention described in claim 1 of the present invention, when coating the surface of the powder or granular material, the powder or granular material is subjected to a stirring force by a stirrer and spreads in a horizontal plane. In addition to rotating while diametrically rotating, it recirculates vertically along the lower surface of the reflux eaves, so that the particles convection along the spiral ring-shaped path, and the distribution of the particles in the flow chamber becomes even. Therefore, even if the surface of the granular material is uneven, the thickness of the coating layer can be made uniform, and it is possible to fully exhibit the coating function while improving the drying efficiency of the modification liquid. Become.

According to the second aspect of the present invention, when the surface of the powder or granular material is coated, the powder or granular material is subjected to centrifugal force due to the rotation of the bottom plate and rotates while expanding its diameter in the horizontal plane. In addition, since the particles are refluxed in the vertical direction along the lower surface of the reflux eaves, the particles are convected along the spiral ring-shaped path, and the distribution of the particles in the flow chamber becomes uniform. Even if the surface of the powder or granular material has irregularities, the thickness of the coating layer can be made uniform, and the coating function can be fully exerted while improving the drying efficiency of the modifying liquid.

According to the third aspect of the present invention, since the powdery particles can be lifted by the flowing air and suspended in the flow chamber, the above-mentioned effect can be made more remarkable. it can.

Further, according to the invention of claim 4 of the present invention, it becomes possible to carry out the surface coating of the granular material under a static pressure environment lower than atmospheric pressure, whereby the solvent of the modifying liquid is vaporized. By lowering the temperature, it is possible to shorten the time required for drying the granular material and thus for the entire surface coating.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a powdery or granular surface coating apparatus according to the present invention.

2A and 2B are views showing an agitator of the surface coating apparatus shown in FIG. 1, in which FIG. 2A is a plan view thereof, and FIG. 2B is an end view taken along line AB of FIG.

FIG. 3 is a cross-sectional view showing a second embodiment of the powdery or granular material surface coating apparatus according to the present invention.

FIG. 4 is a plan view showing a bottom plate of the surface coating apparatus shown in FIG.

FIG. 5 is a schematic cross-sectional view showing an example of a surface coating state by the surface coating apparatus for a powder or granular material according to the present invention.

FIG. 6 is a schematic cross-sectional view showing an example of a state of surface coating by a conventional surface coating apparatus for powder and granules.

[Explanation of symbols]

1 ... Surface coating device for powder and granular material 2 ... Cylinder 4 ... Stirrer 8 ... Bottom plate 8b ... Vent 9 ... Fluid chamber 13 ... Decompression means 14 ... powder 17: Fountain means 20 ... reflux eaves 20a ... bottom surface

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-10-118480 (JP, A) JP-A-7-8782 (JP, A) JP-A-61-230729 (JP, A) JP-A-60- 227855 (JP, A) JP-A-7-246354 (JP, A) Special Table 2-502355 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05B 15/00-15 / 12 B05D 1/02 B01J 2/00-2/30 B01F 7/00-7/32

Claims (4)

(57) [Claims] 1. A stirrer having a cylindrical body (2) having a bottomed cylinder, forming a fluid chamber (9) in the tubular body, and rotating and agitating the granular material (14) in the fluid chamber. (4) is provided, a jetting means (17) for spraying a modifying liquid is provided in the flow chamber, and a powder or granular material formed so as to stand up in a circular arc sectional shape with the bottom peripheral portion of the cylindrical body facing the side surface thereof. Surface coating device (1)
In the upper part of the flow chamber, the reflux eaves (20) is attached to the lower surface (20).
The surface coating device for powdery or granular material is characterized in that a) is recessed from the side surface of the cylindrical body so as to be continuous in an arc cross section. 2. A cylindrical cylinder (2) is provided, and a disk-shaped bottom plate (8) is rotatably provided in the cylinder so that a flow chamber (9) is formed on the upper side thereof. In a surface coating device (1) for a powder or granular material, which is provided with a spray liquid means (17) for spraying a modifying liquid into a chamber, and which is formed so that a peripheral portion of the bottom plate rises in an arc cross section toward the side surface of the cylindrical body. A reflux eaves (20) on the upper part of the flow chamber and a lower surface (20)
The surface coating device for powdery or granular material is characterized in that a) is recessed from the side surface of the cylindrical body so as to be continuous in an arc cross section. 3. A vent (8b) is formed in the bottom plate (8),
3. An air supply means for supplying flowing air from below to above the bottom plate through the vent hole.
The surface coating apparatus for a powder or granular material according to. 4. The surface coating apparatus for a powder or granular material according to claim 1 or 2, further comprising a pressure reducing means (13) for lowering the pressure in the flow chamber (9) below atmospheric pressure.