JPH1133387A - Method and apparatus for batch granulation and coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discharge easily the whole amount of a product by a method wherein a bottom wall central part is opened after granulation or coating, and a product is made to flow down with its dead load to be discharged outside a system. SOLUTION: A porous substrate 12 wherein it presents a disk shape of a crest section forming a taper corresponding to an inner peripheral surface of a through hole 6 on an outer peripheral surface and any vent holes 11 blowing out heated gas upward are provided so as to be freely fitted, separated from (be inserted and extracted) by vertically moving to a through hole 6 of a bottom wall 7 of a container. When granulation or coating and drying operation are ended, after stopping feed of gas with a gas feed pipe 13, spraying with a spray nozzle, and returning a micro particle with an ejector, the porous substrate 12 is lowered, and released from the through hole 6 of the bottom wall 7. An annular clearance 15 is formed between an outer peripheral surface of the porous substrate 12 and an inner peripheral surface of the through hole 6 with downward motion of the porous substrate 12, a product flows down by dead load on an inverted cone cylindrical bottom wall 7 surface of the container 1 without touching of the product to the open air, all is reserved in a tank 16, and exhausted outside the system from a product exhaust opening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a batch granulation / coating method for spraying a binder or a coating agent consisting of a solution or a suspension onto a flowing powder to granulate or coat, and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, a batch granulation / coating method of this kind and an apparatus therefor are disclosed, for example, in Japanese Patent Publication No. 5-8729.
No. 3, JP-B-7-102313 and JP-A-7-102313.
The one described in -289877 is known. These are all provided with a spray nozzle for spraying a binder or a coating agent in a container provided with an exhaust port at the top,
Using a device in which a porous substrate that blows gas upward is provided on the bottom wall of the container, and a product outlet is provided on the side wall near the bottom wall of the container, and a binder or coating agent is used in the container while performing exhaustion at the top. While spraying, the powder circulates and flows repeatedly by rising and falling by the gas blown out from the porous substrate, and after granulation or coating, the product is discharged from the side wall outlet to the outside of the system.

[0003]

However, in any of the conventional batch granulation / coating methods and apparatuses, the product after granulation or coating is horizontally moved from an outlet provided in a side wall near a bottom wall. Since the product is discharged to the outside, the product may remain in the container, and there is a problem that it is difficult to clean the inside of the container when granulating or coating different kinds of powder. Such a tendency becomes remarkable when a stirring blade or the like is provided at the bottom of the container. Accordingly, an object of the present invention is to provide a batch granulation / coating method and a device capable of easily discharging the entire amount of a product.

[0004]

In order to solve the above-mentioned problems, a first batch granulation / coating method of the present invention is to spray a binder or a coating agent in a container in which air is exhausted at an upper part, and The process of circulating and flowing powder by repeating rising and falling by the gas blown upward from the bottom wall center, opening the bottom wall center after granulation or coating, and allowing the product to flow down by its own weight and discharge it out of the system. Features.
The second batch granulation / coating method is characterized in that, in the first method, the fine particles in the exhaust gas are collected by centrifugal force. A third batch granulation / coating method is characterized in that, in the second method, the collected fine particles are returned to the powder in the descending process. On the other hand, the first batch granulation / coating apparatus of the present invention is provided with a spray nozzle for spraying a binder or a coating agent in a container provided with an exhaust port on an upper portion, and an inverted conical cylindrical bottom of the container. A through hole is provided in the center of the wall, and a porous substrate for blowing gas upward is vertically movable so as to be fitted into and removed from the through hole. The second batch granulation / coating apparatus is characterized in that, in the first apparatus, a cyclone is connected to the exhaust port. The third batch granulation / coating device is
The second apparatus is characterized in that an ejector is provided for returning the fine particles collected by the cyclone to a lower portion in the container.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a cross-sectional view showing an example of an embodiment of a batch granulation / coating apparatus according to the present invention, and a cross-sectional view showing an operation of a main part of the apparatus shown in FIG.
In the figure, reference numeral 1 denotes a vertical cylindrical container having a step.
A large-diameter cylinder 3 whose upper end is closed by a ceiling wall 2, a truncated inverted conical cylinder 4 linked to the lower end of the large-diameter cylinder 3, a small-diameter cylinder 5 linked to the truncated inverted conical cylinder 4, and a small-diameter cylinder 5 and a bottom wall 7 having an inverted conical cylindrical shape provided with a tapered through-hole 6 which opens downward at the center portion. In the large-diameter cylinder 3 of the container 1, an exhaust port 8 is provided at an upper part, and a raw material input port 9 for supplying raw material powder is provided at an intermediate portion. A spray nozzle 10 for spraying a binder or a coating agent consisting of a solution or a suspension together with a gas (for example, air) is provided at the center of the intermediate portion.

On the other hand, the through hole 6 in the bottom wall 7 of the container 1 has a disc shape with a mountain-shaped cross section in which a taper corresponding to the inner peripheral surface is formed on the outer peripheral surface, and the heated gas is blown upward. A porous substrate 12 provided with a large number of air holes 11 is provided so as to be able to move up and down to be fitted and disengaged (fitted and disengaged). The porous substrate 12 is moved up and down by moving up and down an air supply pipe 13 vertically provided on the lower surface of the porous substrate 12 through an elevating means 14 such as an air cylinder so as to supply gas to each ventilation hole 11. Container 1
The product discharged from an annular gap 15 (see FIG. 2) formed between the outer peripheral surface of the porous substrate 12 and the inner peripheral surface of the through-hole 6 due to the lowering of the porous substrate 12 is provided on the lower surface of the bottom wall 7 of the substrate. A tank 16 for temporarily storing air is vertically provided in an airtight manner so as to allow an airtight and slidable insertion of the air supply pipe 13, and a product outlet through a valve 17 is provided at a lower end of the tank 16. 18 are provided. On the other hand, the exhaust port 8 of the container 1
The cyclone 20 having the exhaust pipe 19 projecting upward is connected to the connecting pipe 2.
1, a hopper 22 for accommodating the collected fine particles is connected to the lower end of the cyclone 20. An ejector 23 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 22 via a connecting pipe 24.

In order to granulate or coat using the batch granulating / coating apparatus having the above structure, first, raw material powder is charged into the container 1 through the raw material charging port 9 and the air supply pipe 1 is charged.
3, the heated gas is supplied, the gas is blown upward from each of the air holes 11 of the porous substrate 12, and the binder or the coating agent is sprayed from the spray nozzle 10 using the gas. Delivers heated gas. 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. You.
On the other hand, the fine particles that have risen beyond the spray area by the spray nozzle 10 and have reached the freeboat area are partially dropped by their own weight and circulated and flowed, and the remainder is as shown by arrows B and C in FIG. The gas enters the cyclone 20 together with the gas from the exhaust port 8, is collected by centrifugal force, and is stored in the hopper 22. The gas from which the fine particles have been removed
It is released from the exhaust pipe 19 to the atmosphere. And hopper 2
The fine particles contained in 2 are returned by the ejector 23 into the powder in the process of descending from the tangential direction of the small-diameter cylinder 5 of the container 1. When returning the fine particles by the ejector 23, the cyclone 2 is adjusted by adjusting the gas flow rate.
A moderate downward airflow occurs at zero, and the collection efficiency is further improved. Next, when the above-described granulation or coating and drying operations are completed, the supply of gas by the air supply pipe 13, the spraying by the spray nozzle 10 and the return of fine particles by the ejector 23 are stopped, and as shown in FIG. The flexible substrate 12 is moved down and detached from the through hole 6 in the bottom wall 7. Due to the downward movement of the porous substrate 12, an annular gap 15 is formed between the outer peripheral surface and the inner peripheral surface of the through hole 6, and as shown by an arrow D in FIG. The liquid flows down on the surface of the inverted conical cylindrical bottom wall 7 of the container 1 by its own weight and is all stored in the tank 16, and is stored in another container (not shown) or the like from the product discharge port 18.

In the above-described embodiment, a case has been described in which fine particles in exhaust gas are collected by a centrifugal force using a cyclone. However, the present invention is not limited to this. An arranged bag filter or the like may be used. Also, the method is not limited to returning the fine particles collected by the cyclone into the powder in the descending process using the ejector from the tangential direction of the small-diameter cylinder of the container,
At the time of the next operation, it may be put into the container together with the raw material powder. Furthermore, the case of the positive pressure operation by the discharge blower has been described, but the present invention is not limited to this, and the operation may be performed with the tank static pressure being zero by using the negative pressure operation by the suction blower or both.

[0009]

As described above, according to the first batch granulation / coating method and the apparatus of the present invention, the product flows down on the bottom wall surface of the inverted conical cylindrical shape by its own weight, and the product flows in the central portion. Since all of the product is discharged from the through hole, the entire amount of the product can be easily discharged. According to the second batch granulation / coating method and its apparatus, in addition to the function and effect of the first method and its apparatus, it is possible to efficiently collect fine particles in exhaust gas and to make the structure easy to clean. It can be. Further, according to the third batch granulation / coating method and its apparatus, in addition to the effects of the second method and its apparatus, waste of the raw material powder can be omitted, and the circulating flow of the powder can be reduced. The particles can be returned without hindrance, and the use of an ejector can increase the cyclone collection efficiency.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing an operation of a main part of the apparatus of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 6 Through-hole 7 Bottom wall 10 Spray nozzle 12 Porous substrate 20 Cyclone 23 Ejector

Claims (6)

[Claims] 1. A method in which a binder or a coating agent is sprayed in a container in which air is exhausted at an upper portion, and the powder is circulated and flowed by repeating rising and falling by a gas blown upward from a central portion of a bottom wall of the container. Alternatively, a batch granulation / coating method characterized in that a bottom wall center portion is opened after coating, and the product is caused to flow down by its own weight and discharged out of the system. 2. The batch granulation / coating method according to claim 1, wherein the fine particles in the exhaust gas are collected by centrifugal force. 3. The batch granulation / coating method according to claim 2, wherein the collected fine particles are returned to the powder in a descending process. 4. A spray nozzle for spraying a binder or a coating agent in a container provided with an exhaust port at an upper portion,
Batch granulation, characterized in that a through hole is provided in the center of the bottom wall of the inverted conical cylindrical shape of the container, and the porous substrate that blows out gas upwards and downwards is provided so as to be fitted into and detachable from the through hole. Coating equipment. 5. The batch granulation / coating apparatus according to claim 4, wherein a cyclone is connected to the exhaust port. 6. The batch granulation / coating apparatus according to claim 5, further comprising an ejector for returning the fine particles collected by the cyclone to a lower portion of the container.