JPH03217258A - Classification of powder and production of composite material - Google Patents

Abstract

PURPOSE:To inhibit the aggregation and breaking of particles even in the case of fine powder of submicron order and to efficiently classify the powder without sticking to an apparatus, etc., by feeding the powder into a co-underflow generator, dispersing the powder and carrying out dispersion with a cyclone. CONSTITUTION:Powder is fed into a co-underflow generator A composed essentially of a feed part 1, an ejection hole 2, a circular slit 3 for introducing gas from a horizontal direction, a curved slope 4, a gas feed pipe 5 and a distribution part 6. The fed powder is dispersed and a flow of the dispersed powder is continuously classified with a cyclone B. Immediately after this classification, the powder is preferably mixed. The aggregation and breaking of particles are inhibited even in the case of fine powder of submicron order and the powder can be efficiently classified with high performance without sticking to the apparatus and the surface of the inner wall of a conveying system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for classifying powder and manufacturing a composite material. More specifically, the present invention aims to suppress the agglomeration of even fine powders on the micron order, and enable highly efficient classification and uniform dispersion and mixing of the powders into composite materials. This article relates to classification methods and mixing methods.

《Conventional technology and its problems》 Classification and utilization of fine powders have been advanced in various fields for some time, and it is possible to classify particles of various sizes and shapes such as granules, irregular shapes, and fine fibers. However, various methods have been used to obtain and utilize uniformly sized objects. For example, a method of classifying powder using a cyclone or a method of classifying powder using a jet stream has been known so far.

However, in these conventional methods, powder of submicron order or smaller size is
It is extremely difficult to classify the powder while suppressing its secondary agglomeration, so it is necessary to deagglomerate the fine powder, suppress its re-agglomeration, and perform the specified classification without damaging the shape or size of the powder. was difficult. This problem is due to the fact that the finer the powder, the more likely it is that the powder will form aggregates due to secondary agglomeration. On the other hand, in all of the conventional methods, powder tends to adhere to the walls of the classification equipment and conveyance pipes, and this naturally limits the improvement of productivity in powder classification. .

For this reason, we have developed a method and device that can classify powder with high efficiency by suppressing agglomeration or destruction even for fine powders on the submicron order, as well as application methods using this method. Realization was strongly desired.

This invention was made in view of the above circumstances, overcomes the limitations of the conventional method, and achieves submicron order W! A new powder that suppresses agglomeration and destruction of particles, even if it is a fine powder, and prevents the powder from adhering to the walls of the equipment or conveyance system, making it possible to classify with high performance and efficiency. The purpose of this invention is to provide a classification method and a method for manufacturing a composite material as a method for utilizing the classified powder.

(Means for Solving the Problems) In order to solve the above problems, the present invention involves supplying powder to a Coanda flow generating device and dispersing it, and continuously cyclone classifying this dispersed powder flow. The present invention provides a characteristic method for classifying powder and an apparatus for the same.

The present invention also provides a method for producing a composite material by immediately mixing the classified powder without agglomerating it.

The powder targeted by the method of this invention is not particularly limited in its shape, and can be in any shape such as granules, pellets, short fibers, or irregular shapes, and its size can also be
It also targets fine powders on the micron and submicron orders.

Of course, there is no limit to the types. It may be made of any metal, ceramic, polymer, etc. The classification method of the present invention for such powders utilizes a cyclone as well as the fluid phenomenon caused by Coanda flow, and has been completed by highly processing the characteristics of Coander flow. It is difficult to achieve the intended purpose of this invention using only cyclones. This Coanda flow is characterized by large speed and density differences between the axial flow of the fluid and its surroundings, and a dynamic boundary area is formed near the flow channel wall. When combined with a vector, a unique spiral flow is formed. Utilizing these characteristics, the inventors of the present invention have already made many technical proposals regarding the generation of Coanda flow and its applications.

Hereinafter, the method and apparatus of the present invention will be described in more detail with reference to the accompanying drawings.

Figures 1 and 2 of the accompanying drawings show an example of the apparatus of the present invention. For example, as shown in FIG. 1, the powder classification method of the present invention has a combined structure in which a Coanda flow generator as a unit (A) and a cyclone device as a unit (B) are connected. Of course, this unit (A) (
Although B) may be structurally integrated, it can be considered that they are functionally connected. The unit (A) is a powder introduction part using Coanda flow, and as illustrated in FIG. ) and the curved inclined surface (4) near the annular slit (3), as well as the gas supply pipe (5) and the distribution section (6).
)have. The powder to be treated is introduced through the supply port (1), and is transported to the next unit (
Transport the powder to the cyclone device in B). The pressurized gas forms a Coanda flow along the curved inclined surface (4), and
In this example, a spiral motion is generated in the powder flow.

Further, in the cyclone device of unit (B), powder is classified by various methods.

The pressurized gas blown through the annular slit (3) of the unit (A) can be any suitable gas such as air, inert gas, or reactive gas, and can be used depending on the type and physical properties of the powder, as well as the purpose. It can be selected depending on the characteristics of the classification. The gas can be pressurized generally from 1 to 10 kJr/cd, further below or above,
Set according to the amount of powder to be introduced, flow rate, etc. The solid-gas ratio can also be selected within a wide range.

In addition, the inclination angle of the curved inclined surface (4) can be varied widely, and a Coanda flow, especially a Coanda spiral flow in this example, is generated and the inclination angle of about 20 to 70 degrees is assumed to be a state in which this is not destroyed. It can be an angle. In the apparatus of the present invention having these specific requirements and the powder coating method using the same, the unit (
A) and a functional configuration with unit (B) are essential.

The first reason is that this unit ( A
＞ is indispensable.

In addition, powders with good dispersion can be made into high-performance powders.
Unit (B) is essential for highly efficient classification. Of course, the format of the unit (B) may be arbitrary.

In addition, the powder classified in unit (B) is transferred to the unit (C) shown in Fig. 1 to prevent secondary agglomeration from occurring again.
) is preferably immediately supplied to its utilization system. An example of such a system is a composite material manufacturing line.

FIG. 3 shows another example. In this example, two Coanda flow generators are used as units (AI) (A2). A Coanda flow generation device is used that has a curved surface (4') instead of the curved inclined surface (4) in the example shown in FIG. This unit (A,) generates Coanda flow but not spiral motion. However, the unit (A2
) generates a spiral motion. For example, as shown in FIG. 3, the Coanda flow generation device may include a normal Coanda unit and a Coanda spiral unit as appropriate units (AI>
(A2) may be used in combination, or only the unit (A1) may be used. ? An embodiment of the invention will now be described.

EXAMPLE S102 powder was classified using the apparatus shown in FIGS. 1 and 2. Pressurized air '3h/No. 1 Coanda spiral flow generation system! was connected to a cyclone. In this method, the recovery rate of submicron powder of SiO2 was 98%.

On the other hand, in the case of conventional classification using only a cyclone without using a Coanda flow device, the recovery rate of SiO2 submicron powder was only 70%.

The SiO2 submicron powder recovered with high efficiency could be immediately dispersed in resin to form a composite material. The dispersion was uniform and in good condition. (Effects of the Invention) As explained in detail above, this invention suppresses secondary agglomeration of powder, provides high performance, without damage to powder,
Classification with high efficiency becomes possible.

Furthermore, secondary agglomeration after classification can be suppressed, making it possible to produce a high-quality composite material.

[Brief explanation of drawings]

FIGS. 1 and 2 are a configuration diagram and a partial sectional view showing an embodiment of the apparatus of the present invention. Moreover, FIG. 3 is a partial sectional view showing yet another example of a Coanda flow generation device. ■... Supply port 2... Discharge port 3... Annular slit 4... Curved inclined surface 4'... Curved surface 5... Gas supply pipe 6... Distribution part

Claims (2)

[Claims] (1) A method for classifying powder, which comprises supplying powder to a Coanda flow generator, dispersing it, and continuously subjecting the dispersed powder flow to cyclone classification. (2) A method for producing a composite material, characterized in that the powder is mixed immediately after the classification according to claim (1).