JP3147225B2 - Continuous granulation / coating method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous granulation / coating method and an apparatus for continuously granulating or coating by spraying a binder or a coating agent composed of a solution or a suspension onto a flowing powder. .

[0002]

2. Description of the Related Art Conventionally, as a continuous granulation / coating method of this kind and an apparatus therefor, for example, Japanese Patent Publication No. 7-5731
A continuous granulation apparatus described in Japanese Patent Application Publication No. 1 is known. This continuous granulation apparatus is provided with a screw-type unloader for unloading products at a lower portion of a fluidized tank, and a lower portion of the unloader is a ventilator that can be ventilated by a blower. A part of the powder during granulation is taken out of the fluidized tank, classified during transportation, and the powder having the required particle size is discharged as a product. The powder smaller than the diameter is returned to the fluidized tank.

[0003]

However, according to the conventional continuous granulation method and the conventional apparatus, a part of the powder during granulation is taken out from one place on the lower side of the fluidized tank, so that the required particle size is required. Cannot be effectively discharged, the product has a wide particle size distribution, and the granulation efficiency is lowered. Therefore, an object of the present invention is to provide a continuous granulation / coating method and a device capable of sharpening the particle size distribution of a product and dramatically increasing the granulation or coating efficiency.

[0004]

In order to solve the above-mentioned problems, a continuous granulation / coating method according to the present invention is characterized in that a binder or a coating agent is sprayed in a container to which a raw material powder is supplied while exhausting air at an upper portion. The gas is blown upward from the center of the bottom wall of the container, and the powder is repeatedly raised and lowered to circulate and flow the powder, which is required during the transition process from falling to rising over the entire periphery of the bottom wall of the container. The method is characterized in that particles having a particle size or more are classified into a gas having a variable particle size and discharged out of the system. On the other hand, the continuous granulation / coating apparatus of the present invention
A spray nozzle for spraying a binder or a coating agent is provided in a container provided with an exhaust port at an upper portion and a tank for supplying raw material powder, and a through hole is provided in a central portion of a bottom wall of the container to supply gas. The porous substrate that is blown upward is disposed so as to form an annular gap having a variable width between the outer peripheral surface and the inner peripheral surface of the through hole, and is classified into the annular gap on the lower surface of the bottom wall of the container. It is characterized in that an air supply cylinder for supplying the working gas is vertically provided.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a sectional view showing an example of an embodiment of a continuous granulation / coating apparatus according to the present invention, and an enlarged view of a main part of FIG. In the figure, reference numeral 1 denotes a cylindrical vertical container having a step. The container 1 includes a large-diameter cylinder 3 whose upper end is closed by a ceiling wall 2 and a truncated inverted conical cylinder 4 connected to the lower end of the large-diameter cylinder 3. And a small-diameter cylinder 5 connected to the lower end of the truncated inverted conical cylinder 4, and an inverted conical cylinder connected to the lower end of the small-diameter cylinder 5 and having a tapered through-hole 6 formed at the center and expanding downward. And a bottom wall 7 in the shape of a circle. Large-diameter cylinder 3 of container 1
An exhaust port 8 is provided in the upper part, a raw material input port 9 for inputting raw material powder at the start of processing is provided in an intermediate part, and a solution or suspension is provided in the large-diameter cylinder 3. A spray nozzle 10 for spraying a binder or a coating agent composed of a turbid liquid together with a gas (for example, air) is provided at the center of the intermediate portion.

On the other hand, the inside of the through hole 6 in the bottom wall 7 of the container 1 has a disk shape having a mountain-shaped cross section in which a taper corresponding to the inner peripheral surface is formed on the outer peripheral surface, and heated gas is directed upward. A porous substrate 12 provided with a large number of vent holes 11 to be blown is disposed so as to form an annular gap 13 serving as an outlet for powder particles between an outer peripheral surface thereof and an inner peripheral surface of the through hole 6. ing. On the lower surface of the porous substrate 12, an air supply pipe 14 for supplying gas to each of the ventilation holes 11 is vertically provided. The air supply pipe 14 is provided with an air cylinder or the like in order to make the width of the gap 13 variable. It is provided so as to be able to move up and down via lifting means 15. or,
On the lower surface of the bottom wall 7 of the container 1, an air supply cylinder 16 which also serves as a tank for temporarily storing the powder (product) discharged from the gap 13 and supplies heated gas for classification to the gap 13.
The air supply pipe 14 is vertically suspended to allow air-tight and slidable insertion. An air supply port 17 for heating gas for classification is provided at an intermediate portion of the air supply cylinder 16. In the department,
A product outlet 19 is provided via a valve 18. On the other hand, a cyclone 21 having an exhaust pipe 20 projecting upward is connected to the exhaust port 8 of the container 1 via a connecting pipe 22. A lower end of the cyclone 21 has a hopper for storing collected fine particles. 23 are provided in series. An ejector 24 that returns the fine particles from the tangential direction into the small-diameter cylinder 5, which is a lower part of the container 1, using a heated gas is connected to a lower portion of the hopper 23 via a connecting pipe 25. Is connected to a tank 26 for supplying raw material powder via a connection pipe 28 having a rotary valve 27 interposed therebetween.

[0007] In order to continuously granulate or coat using the continuous granulating / coating apparatus having the above configuration, first,
The air supply pipe 14 is raised to close the gap 13, and the raw material powder is charged into the container 1 from the raw material input port 9, and heated gas is supplied from the air supply pipe 14, and the air holes 11 of the porous substrate 12 are formed.
, A relatively high-speed (15 m / s) gas is blown upward, and the binder or coating agent is sprayed from the spray nozzle 10 using the gas. Next, the air supply pipe 14 is lowered to make the gap 13 have a required width, and heated gas is supplied from the air supply port 17.
/ S) is blown obliquely upward, and the heated gas is supplied to the ejector 24. As a result of this operation, the raw material powder is granulated or coated and dried while being circulated and flown, as shown by the arrow A in FIG. And all of it
In the process of transition from descending to ascending in the entire circumference of the bottom wall peripheral portion, the gas is subjected to classification by the gas blown out from the annular gap 13, and particles having a required particle size or more fall from the gap 13 as shown by an arrow B in FIG. While being temporarily stored at the bottom of the supply cylinder 16 and discharged out of the system by opening and closing the valve 18, particles smaller than the required particle size are again circulated and flowed to be granulated or coated and dried. On the other hand, the fine particles that have risen beyond the spray area by the spray nozzle 10 and have reached the freeboard area are partially dropped by their own weight and circulated and flown, and the remainder is exhausted as shown by arrows C and D in FIG. The gas enters the cyclone 21 through the port 8 together with the gas, is collected by centrifugal force, and is stored in the hopper 23. The gas from which the fine particles have been removed is discharged from the exhaust pipe 20 to the atmosphere. Then, the fine particles stored in the hopper 23 are returned by the ejector 24 into the powder in the descending process from the tangential direction of the small-diameter cylinder 5 of the container 1. When the fine particles are returned by the ejector 24, by adjusting the gas flow rate, an appropriate downward airflow is generated in the cyclone 21 and the collection efficiency is further improved. Also, the annular gap 13
The amount of raw material powder corresponding to the amount of product discharged from
As shown by the arrow E, the powder is supplied from the tank 26 to the powder in the descending process via the ejector 24 with the opening and closing of the rotary valve 27, and continuous granulation or coating and drying are performed.

In the above-described embodiment, the case where the width of the annular gap is variable has been described. However, the present invention is not limited to this case. You may make it become.

[0009]

As described above, according to the continuous granulation / coating method and the apparatus of the present invention, the powder in the granulation or coating that circulates and flows is formed in the peripheral portion of the bottom wall of the container.
In the process of transition from descending to ascending in the entire circumference of the gas, all particles are classified into variable particle diameters, and particles larger than the required particle diameter are immediately discharged out of the system, so that the particle size distribution of the product can be sharpened and granulation or coating Efficiency can be dramatically improved, and it can be adapted to the properties of the product.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a continuous granulation / coating apparatus according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 6 Through-hole 7 Bottom wall 8 Exhaust port 10 Spray nozzle 12 Porous substrate 13 Gap 16 Gas supply cylinder 21 Cyclone 24 Ejector 26 Tank A Arrow B Arrow

Claims (2)

(57) [Claims] 1. Exhaust gas is discharged from the upper part, and a binder or a coating agent is sprayed in a container to which raw material powder is supplied, and the powder is repeatedly raised and lowered by a gas blown upward from a central portion of a bottom wall of the container. Circulates and circulates the body, the bottom wall of the container
A continuous granulation / coating method characterized in that particles having a required particle size or more are classified into a gas having a variable particle size and discharged out of the system in a transition process from falling to rising of the powder over the entire periphery of the peripheral portion . 2. A spray nozzle for spraying a binder or a coating agent is provided in a container provided with an exhaust port at an upper portion and a tank for supplying raw material powder, and a through hole is provided at a center of a bottom wall of the container. The porous substrate that blows gas upward is disposed so as to form an annular gap having a variable width between the outer peripheral surface and the inner peripheral surface of the through hole, and the porous substrate is provided on the lower surface of the bottom wall of the container. A continuous granulation / coating apparatus characterized in that an air supply cylinder for supplying a classifying gas is vertically provided in an annular gap.