JPH11222291A - Method for putting in powder by preventing powder separation, and reservoir for preventing powder separation having umbrella-shaped structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preventing powder separation occurring when powder is put into a reservoir. SOLUTION: The method for putting in powder includes a step of guiding powder to drop to a corner inner wall face of a column 2 of a reservoir 1 from a throw-in point of the powder by an umbrella-shaped structure placed in the column 2 of the reservoir 1 at the time of putting the powder containing mixed powder or fine particles into the reservoir 1 comprising the parallelopiped column 2. The reservoir 1 comprises the parallelopiped column 2, wherein a powder throw-in port 3 is provided on an upper part of the column 2 and a powder discharge port 4 is provided on a lower part. The umbrella-shaped structure 5 comprising a pyramid 6 and a slope 7 further provided on a lower side of the pyramid 6 is placed in the column 2 of the reservoir 1, wherein an apex of the pyramid 6 of the umbrella-shaped structure 5 is immediately below the powder throw-in port 3, and a lower end of the slope 7 is extended from a lower face of the pyramid 6 toward the corner inner wall face 2a of the column 2 of the reservoir 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing powder separation that occurs when a mixed powder or a powder containing fine powder is charged into a storage tank, and more particularly to a mixed powder for powder metallurgy. TECHNICAL FIELD The present invention relates to a technique for preventing powder separation that occurs when pouring into a storage tank.

[0002]

2. Description of the Related Art Metal powders for powder metallurgy are produced by an atomizing method, an oxide reduction method or the like. These metal powders are subjected to a homogenizing treatment by a blender or the like in order to uniform the variation in the particle size distribution. Metal powders for powder metallurgy have a wide particle size distribution range and relatively often contain fine powder. This is because a powder containing a fine powder and having a wide particle size distribution can increase the density of the compact at the time of molding, and can increase the density of sintered machine parts and the like. Recently, there has been an increasing demand for powdered metallurgy mixed powders in which different kinds of metal powders are mixed in advance and additives (graphite powders, lubricants, etc.) are further mixed. This is because there is no need for a user to perform powder mixing processing and mixing equipment.

[0003] For this reason, powders that have been mixed by a blender or a mixer or that have been subjected to a homogenization process to reduce the variation in particle size distribution are divided into small lots and shipped to each user. This subdivision is performed by once charging powder into a storage tank from a blender or a mixer, and then transferring a predetermined amount from a powder discharge port below the storage tank to a transfer container (for example, a flexible container). ing.

[0004] When a mixed powder or a homogenized powder is charged into a storage tank, the powder falling in the storage tank is released into the atmosphere for each individual particle. A mixed powder for powder metallurgy often contains a plurality of types of powders having different falling speeds.

When such a mixed powder for powder metallurgy is charged into a storage tank, powder having a low specific gravity, such as graphite powder, has a greater influence on the air resistance during the fall, and falls in the air more than other metal powders. The speed becomes slower and it is more likely to fly into the storage tank. Fine powder (particle size of 45 μm or less)
In the case of powders containing fine particles, the fine powder is greatly affected by the air resistance during the fall, and the falling speed in the air is slower than that of other metal powders having a large particle size, so that the fine powder is scattered in the storage tank. As described above, the scattered powder often floats in the cylindrical portion of the storage tank and adheres to the inner wall surface of the cylindrical portion. Particularly, when the cylindrical portion of the storage tank has a square shape, the powder on the inner wall surface of the cylindrical portion in the storage tank is often used. The amount of adhesion to corners increases.

[0006] Thereafter, these powders charged into the storage tank are sequentially deposited and deposited so as to cover the inner wall surface of the cylindrical portion in the storage tank to which the scattered powder adheres. For this reason, the powder having a low falling speed in the atmosphere (powder or fine powder having a small specific gravity) is concentrated on the inner wall surface of the cylindrical portion, particularly on the inner wall portion of the cylindrical portion, and the powder is separated in the storage tank. ,
Component segregation or particle size segregation will occur. Therefore, there arises a problem that the component and the particle size distribution of the powder discharged from the powder discharge port at the lower portion of the storage tank are not always constant.

Normally, when the metal powder or mixed powder for powder metallurgy is discharged from the lower outlet of the storage tank, a funnel flow preferentially discharged from the powder at the center of the storage tank often occurs. . When this funnel flow occurs, the powder on the inner wall of the corner portion in the storage tank that is far from the center of the storage tank and is loose is discharged at the latest, and adheres to the inner wall surface of the cylindrical portion at the end of the discharge. As a result, powder or fine powder having a small specific gravity is discharged, and component segregation or particle size segregation occurs.

[0008] When such component segregation or particle size segregation occurs in the powder, the weight during molding and the rate of dimensional change during sintering vary in the production of sintered mechanical parts, and the product yield decreases. Furthermore, there is a problem that the reliability of the mechanical properties of the sintered machine component is reduced due to the component segregation.

As a countermeasure against this, (a) Japanese Patent Publication No. 55-8905 and Japanese Utility Model Application Laid-Open No. 58-59785 have disclosed a method of preventing powder segregation at the time of powder input by using a container. There is disclosed a method of supplying so as to sequentially deposit from the lower part. In addition, (b) Japanese Patent Application Laid-Open No. 56-74468 and Japanese Patent Publication No. 2-7852 disclose an umbrella-shaped structure provided at the upper part of a container to classify or disperse a charged powder and a structure for cutting out. Is provided at the bottom of the container to obtain a powder having a uniform particle size distribution. further,
(C) Japanese Patent Publication No. 1-31616, Japanese Patent Publication No. 2-785
No. 2 discloses a method for preventing segregation at the time of discharging from a container even if the powder after the introduction of the powder has segregation.

[0010]

However, (A)
Although it is ideal to supply the powder in such a way that the powder is sequentially deposited from the lower part of the container, the apparatus needs to be moved in the height direction, and the structure is very large, complicated, and expensive.

The method of (b) in which the umbrella-shaped structure is provided on the upper part of the container to classify or disperse the charged powder simply involves dispersing the powder at the time of charging and is affected by air resistance. It is not enough to prevent scattering of powder having a low falling speed in the air (powder or fine powder having a low specific gravity) or adhesion to the inner wall surface of the container. Furthermore, these methods require a cutting structure for cutting out the powder, so that the structure of the container is complicated.

(C) Even if the powder after the introduction of the powder is segregated, a method of preventing segregation at the time of discharge from the container is based on a plurality of extraction methods for uniformly discharging the powder in the container. An inner cylinder with holes is required in the container. Further, powder adheres and accumulates easily on the inner and outer surfaces of the inner cylinder, and since the structure is complicated, it is difficult to clean the inner cylinder. There is a risk that old powder or powder of other components may be mixed with new powder.

That is, the above three methods have a problem that a large-scale apparatus must be provided in each container into which the powder is charged. The present invention has been made to solve the above problems, and by using a simple umbrella-shaped structure provided in the cylindrical portion of the storage tank, the powder separation that occurs when the powder is charged into the storage tank. It is an object of the present invention to provide a powder charging method capable of suppressing component segregation and particle size segregation during powder discharge.

[0014]

The gist of the present invention is that when powder containing mixed powder or fine powder is charged into a storage tank having a square cylindrical portion, the powder is placed in the cylindrical portion of the storage tank. A powder input method for preventing powder separation, characterized in that the provided umbrella-shaped structure guides the powder from the input point of the powder to the inner wall surface of the cylindrical portion of the storage tank and drops the powder. Here, as the umbrella-shaped structure, a pyramid, preferably a pyramid having an inclined portion provided on the lower side of the pyramid is used.

In addition to the above, in a storage tank which is formed of a square cylindrical part and has a powder inlet at the upper part and a powder outlet at the lower part, a pyramid is provided in the cylindrical part of the storage part. An umbrella-shaped structure further provided with an inclined portion on the lower side of the pyramid is disposed, the apex of the pyramid is directly below the powder inlet, and the lower end of the inclined portion is the storage tank from the lower side of the pyramid. A storage tank for preventing powder separation, having an umbrella-shaped structure extending toward the inner wall surface of the corner of the cylindrical portion.

[0016] The powder charging method for preventing powder separation or the storage tank for preventing powder separation having an umbrella-like structure according to the present invention is preferably applied to a powder mixture for powder metallurgy. further,
It is preferably used when a funnel flow is caused when the powder is discharged from the powder discharge port of the storage tank.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram of a storage tank having an umbrella-shaped structure according to an embodiment of the present invention. As shown in FIG. 1, a storage tank 1 having an umbrella-shaped structure according to an embodiment of the present invention has a rectangular cylindrical portion 2.
A powder inlet 3 is provided at an upper portion of the cylindrical portion 2, a funnel-shaped inverted pyramid portion 7 is provided at a lower portion of the cylindrical portion, and a powder outlet 4 is provided at a vertex of the inverted pyramid portion 9. An umbrella-shaped structure 5 is provided in the cylindrical portion 2 of the storage tank 1. The umbrella-shaped structure 5 has a quadrangular pyramid 6
And an inclined portion 9 further provided on the lower side 6c of the quadrangular pyramid. The vertex 6a of the quadrangular pyramid of the umbrella-shaped structure is directly below the powder inlet 3, and the inclined portion 7 extends from the lower side 6c of the quadrangular pyramid to the corner inner wall surface 2a of the cylindrical portion of the storage tank. ing. At this time, it is preferable that the inclination angle from the vertex 6a of the quadrangular pyramid of the umbrella-shaped structure 5 to the lower side 6c of the quadrangular pyramid and the inclination angle of the inclined portion 7 are larger than the angle of repose. In this embodiment, the angle of repose of the metal powder for powder metallurgy used in the embodiment is 3
Since they are in the range of 0 to 40 °, these inclination angles were set to 45 °.

FIG. 1 shows a mixed powder or a powder containing fine powder.
When the powder is continuously charged from the powder charging port 3 into the storage tank shown in FIG.
It is guided from the vertex 6a of the quadrangular pyramid of the umbrella-like structure 5 to the inner wall surface 2a of the cylindrical portion of the storage tank. At this time, the angle of inclination of the umbrella-shaped structure is larger than the angle of repose, so that the powder flows smoothly to the lower end 7a of the inclined portion of the umbrella-shaped structure 5, and thereafter, the corner inner wall surface 2a of the cylindrical portion of the storage tank. Let it fall.

These powders are released into the atmosphere for each individual particle. However, since the umbrella-like structure guides the powder to the inner wall surface of the cylindrical portion of the storage tank and drops it, Since the distance between the lower end 7a of the inclined portion of the umbrella-like structure 5 and the inner wall surface 2a of the corner portion of the cylindrical portion is short, scattering of powder or fine powder having a small specific gravity is reduced. On the other hand, even if these scattered powders adhere to the corner inner wall surface 2a of the cylindrical portion, the powder is continuously supplied to the corner inner wall surface 2a, so that the scattering of the powder can be prevented, The chance of concentrating easily scattered powders (powder with small specific gravity or fine powder) can be significantly reduced.

The distance between the lower end 7a of the inclined portion of the umbrella-shaped structure 5 and the inner wall surface 2a of the cylindrical portion of the storage tank is set to a distance that allows the supplied powder to reach the inner wall surface 2a of the cylindrical portion. This distance is set according to the angle of repose of the powder and the angle of inclination of the umbrella-like structure. Further, this distance can be reduced to such an extent that the flow of the charged powder is not hindered. Thereby, scattering of powder or fine powder having a small specific gravity can be further reduced. Further, the lower end 7a of the inclined portion of the umbrella-shaped structure 5
The powder that has been charged to the end is the inner wall surface 2 of the cylindrical portion.
Within the range that can reach a, it is possible to approach the final deposition position of the charged powder. Thereby, it is possible to further prevent adhesion of powder or fine powder having a low specific gravity.

Further, it is preferable that the powder supply port 8 and the apex 6a of the quadrangular pyramid of the umbrella-like structure are brought close to each other within a range that does not hinder the flow of the powder to be charged. In the space between the powder supply port 8 and the apex 2a of the quadrangular pyramid of the umbrella-like structure, scattering of powder or fine powder having a low specific gravity can be suppressed.

As described above, the umbrella-shaped structure disposed in the cylindrical portion of the storage tank guides the powder composed of the powders having different falling speeds in the atmosphere to the inner wall surface of the corner portion of the cylindrical portion of the storage tank to drop. Thus, powder separation of the powder charged into the storage tank is prevented.

Next, in order to confirm the effect of preventing powder separation of the powder charged into the storage tank of the present invention, the state of component segregation at the time of discharging the powder was examined. In the embodiment of the present invention, 3 tons of the mixed powder for powder metallurgy is put into the storage tank (see FIG. 1) having the above-mentioned umbrella-shaped structure of the present invention, and the powder is discharged from the powder outlet of this storage tank. At the same time, sampling was performed at predetermined intervals to investigate the segregation state of the mixed powder. As shown in FIG. 1, the storage tank used in the present embodiment has a cylindrical portion with a side of 1200 mm.
And the length of the cylindrical portion is 1200 mm. The powder inlet 3 is provided on the upper part of the cylindrical portion. A funnel-shaped inverted pyramid portion 9 having an inclination angle of 45 ° is provided from the lower part of the cylindrical portion, and the powder discharge port 4 is provided at the top of the inverted pyramid portion 9, that is, below the storage tank. The distance from the powder inlet 3 to the powder outlet is 2000 mm.

As shown in FIG. 1, the umbrella-shaped structure 5 has a square pyramid 6 having a side of 300 mm and an apex angle of 90 ° (the inclination angle formed by the square pyramid is 45 °). From lower side 6c, inclination angle: 45 °, length: 500 mm
Is provided. The umbrella-shaped structure 5 is disposed on the square tubular portion 2, and the lower side 6 c of the regular quadrangular pyramid of the umbrella-shaped structure is disposed so as to face the corner inner wall surface 2 a of the square tubular portion. Further, the inclined portion 7 extends in the direction of the inner wall surface 2a of the corner of the cylindrical portion. Lower end 7 of this inclined part
The distance between a and the square corner of the cylinder of the storage tank is about 345 m
m. Then, the vertex 6a of the regular quadrangular pyramid and the powder supply port 8
Is 150 mm, and the position of the lower end 7 a of the inclined portion is about 1500 mm from the powder discharge port 4.

In the comparative example, an umbrella-shaped structure shown in FIG. 2 was provided in the above-mentioned storage tank having a square cylindrical portion, and the segregation state of the mixed powder for powder metallurgy was similarly examined. 2A to 2D schematically show a comparative example, and E shows an example of the present invention, and schematically shows the storage tank having the configuration shown in FIG. 1 described above. In these comparative examples and examples, an umbrella-shaped structure having regular square pyramids as shown in FIGS. 2A to 2E is arranged in the cylindrical portion of the storage tank, and when the powder is charged into the storage tank, The falling position of the powder in the storage tank was changed. The square pyramids of the umbrella-shaped structures B to D in these comparative examples have a side of 300 mm and the apex angle is 90 °, and have the same shape as the square pyramid of the umbrella-shaped structure E of the present invention.

FIG. 2A shows a case where the umbrella-shaped structure is not arranged, and the powder falls just below the charged state as shown in FIGS. 3A and 3B. Here, a) and b) in FIG.
A in the figure indicates the drop position of the powder. Hereinafter, B to E in FIGS. 3A and 3B also correspond to B to E in FIG.
It corresponds to

FIG. 2B guides the powder in the direction between the inner walls of the cylinder of the storage tank, and FIG. 2C guides the powder in the direction of the inner wall surface of the corner of the cylinder of the storage tank. However,
As shown in FIGS. 3A and 3B, B and C, both powders have a structure in which they fall before reaching the inner wall of the cylindrical portion. FIG. 2D shows 4 of the umbrella structure of FIG. 2B.
The inclined portion is further extended from the base of the pyramid by about 300 mm to the inner wall surface side of the cylindrical portion of the hopper, and the powder is guided to the inner wall surface and dropped, and the lower portion of the cylindrical portion of the storage tank is formed along the inner wall surface. It is made to flow to.

In the embodiment of the present invention shown in FIG. 2E, the inclined portion extends from the base of the pyramid of the umbrella-shaped structure of FIG. 2C to the inner wall surface side of the cylindrical portion of the storage tank. The body is guided to the inner wall surface of the corner and dropped, and flows along the inner wall surface to the lower part of the cylindrical portion of the storage tank.

The test powders used in this example are as follows. These test powders were blended at a predetermined mixing ratio and mixed by a blender to produce a mixed powder for powder metallurgy. Iron powder (water atomized iron powder)-Average particle diameter: about 70 m (-80 mesh)-Angle of repose: 30 to 40 degrees-Specific gravity: 7.87 Copper powder-Average particle diameter: about 80 m-Specific gravity: 8.93 graphite Powder ・ Average particle diameter: about 5 μm ・ Specific gravity: 2.25 Zinc stearate (lubricant) ・ Average particle diameter: about 10 μm ・ Specific gravity: 1.13

In this embodiment, iron powder contains copper powder: 2% by mass (hereinafter referred to as “%”), graphite powder: 0.8%,
A test material (3 tons) was prepared by mixing zinc stearate: 0.8% and mixing with a blender. Next, each of the storage tanks described above is set under the blender, and the mixed test material is allowed to freely fall through the discharge port of the blender (corresponding to the powder supply port 8 in FIG. 1) and is charged into the storage tank. did. The height of the charged powder is 1200 mm from the powder outlet.
And the lower end 7a of the inclined portion of the umbrella-shaped structure 5 as described above.
Is about 1500 mm from the powder discharge port 4. The distance between the lower end 7a of the inclined portion of the umbrella-shaped structure 5 and the inner wall surface 2a of the cylindrical portion of the storage tank is 345 mm.

Next, to confirm the effect of preventing powder separation of the powder charged into the storage tank, the state of component segregation at the time of powder discharge was investigated. Investigating the state of component segregation at the time of discharging this powder,
The powder was discharged from the powder discharge port at the lower part of the storage tank, the powder was sampled at predetermined intervals, and the components were analyzed. The results are shown in Tables 1 to 3 and FIGS. In addition, the amount of graphite shown in Table 2 and the amount of zinc stearate shown in Table 3 were converted from the analysis values of carbon and zinc. That is, the amount of zinc stearate is calculated from the analysis value of zinc, the amount of carbon contained in the amount of zinc stearate is subtracted from the analysis value of the carbon, and the amount of graphite is calculated from the analysis value of the reduced carbon. is there.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

The method of dropping the powder according to the present invention by guiding it to the inner wall surface of the corner of the cylindrical portion (E in FIG. 2) uses a storage tank having an umbrella-shaped structure according to the present invention. As shown in the figure, the standard deviation with respect to each powder amount is smaller than that of the comparative example, and this is a method of charging powder with less segregation. Also, FIG.
As shown in Fig. 6, powders having a low specific gravity (e.g., graphite powder, zinc stearate, etc.), which fall slowly into the atmosphere due to the influence of air resistance, are particularly concentrated in the latter half of discharge, but this tendency is high. In the method for charging powder of the present invention (E in FIG. 2),
The degree of segregation at the final discharge is very small. Thus, in the charging method of the present invention, from the initial stage to the late stage of powder discharge,
It was confirmed that there was almost no change in the mixing ratio of the mixed powder for powder metallurgy and the powder was stable, and that even the powder discharged at the end could be used without any problem.

As described above, as in the embodiment of the present invention, the powder is guided to the inner wall surface of the corner portion of the cylindrical portion to be dropped, so that the conventional storage tank having the square-shaped cylindrical portion in which segregation easily occurs is provided. It became clear that the effect of improving segregation was excellent.

In the embodiment of the present invention, an umbrella-like structure having a quadrangular pyramid and an inclined portion further provided on the lower side of the quadrangular pyramid is used in a storage tank having a quadrangular cylindrical portion. The present invention is not limited to this embodiment, and the present invention can be applied to a case where the cylindrical shape of the storage tank is a polygon such as a triangle or a hexagon. By changing the umbrella-like structure to a polygonal pyramid such as a triangular pyramid or hexagonal pyramid,
An inclined portion is further provided from the lower side of the polygonal pyramid, and the lower end of the inclined portion is extended toward the inner wall surface side of the corner portion of the cylindrical portion of the storage tank. Guided to the inner wall surface of the corner of the part and dropped, there is also an effect of improving segregation.

Further, the umbrella-like structure in the embodiment of the present invention is as follows:
It consists of a quadrangular pyramid and an inclined portion further provided on the lower side of this quadrangular pyramid, but further enlarges the quadrangular pyramid of the umbrella-like structure, and extends the lower end of this quadrangular pyramid to the inner wall surface side of the corner of the cylindrical portion of the storage tank The same effect of improving segregation can be expected by guiding the powder from the input point to the inner wall surface of the cylindrical portion of the storage tank and dropping it. That is, the powder charging method of the present invention for preventing powder separation is to prevent powder separation by guiding the powder from the charging point to the inner wall surface of the cylindrical portion of the storage tank and dropping the powder. The body only needs to have such a function. For this reason, the umbrella-shaped structure used in the powder charging method for preventing powder separation of the present invention consists only of pyramids, and the lower end of the pyramids extends toward the inner wall surface of the corner of the cylindrical portion of the storage tank. What is necessary is just to be able to guide the body from the input point to the inner wall surface of the corner of the cylindrical portion of the storage tank and drop it.

In this embodiment of the present invention, the mixed powder is used. However, the present invention is not limited to this embodiment, and the method of the present invention for preventing powder separation and the powder having an umbrella-shaped structure are not limited to this embodiment. The storage tank for preventing separation can be used for powder containing fine powder or other mixed powder. That is, the present invention
It is used when a powder containing powder (powder having a small specific gravity or fine powder) which is liable to be scattered under the influence of air resistance during the drop is charged into a storage tank having a square cylindrical portion.

[0040]

As described above, the method for charging powder according to the present invention, which prevents powder separation, uses powder containing mixed powder or fine powder, that is, powder comprising powders having different falling speeds in the atmosphere. When the body is charged into a storage tank having a square cylindrical portion, the powder is disposed in the cylindrical portion of the storage tank, by an umbrella-shaped structure having a simple structure, from the charging point of the powder. By guiding the powder to the inner wall surface of the corner of the cylindrical portion of the storage tank and dropping it, it is possible to prevent powder separation that occurs when the powder is charged into the storage tank. As a result, it is possible to supply a mixed powder with less component segregation and a powder with less particle segregation from the early to late stages of powder discharge.

In particular, a storage tank comprising an angular tubular portion having an umbrella-shaped structure according to the present invention comprises an umbrella-shaped structure comprising a pyramid and an inclined portion further provided on the lower side of the pyramid in the tubular portion of the storage tank. By arranging, even in powder mixed for powder metallurgy mixed with graphite powder having a low specific gravity and easily segregated,
This makes it possible to subdivide a mixed powder with less component segregation into another container without causing powder separation.

[Brief description of the drawings]

1 is an explanatory view of a storage tank having an umbrella-shaped structure according to an embodiment of the present invention, wherein a) is a plan view, b) is a front view, and c) is a cross-sectional view taken along the line xy in the plan view. is there.

FIG. 2 is a view showing an arrangement method of an umbrella-shaped structure according to an example of the present invention and a comparative example.

FIG. 3 is a diagram showing storage tank shapes and falling positions of powder in Examples and Comparative Examples of the present invention. a) is a sectional view of the storage tank, and b) is a plan view of the storage tank.

FIG. 4 is a view showing a state of graphite segregation in an example of the present invention.

FIG. 5 is a view showing a state of segregation of zinc stearate in an example of the present invention.

FIG. 6 is a diagram showing a state of copper segregation in an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage tank 2 Cylindrical part 2a Corner inner wall surface of cylindrical part 3 Powder input port 4 Powder discharge port 5 Umbrella-like structure 6 Square pyramid 6a Square pyramid vertex 6b Square pyramid inclined surface 6c Square pyramid lower part 7 Inclined part 7a Lower end of inclined section 8 Powder supply port 9 Funnel-shaped inverted pyramid

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoshi Masuhara 2-3-1, Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside Kobe Steel, Ltd. Takasago Works (72) Inventor Shinya Arima 2-chome, Araimachi, Takasago City, Hyogo Prefecture No. 1 Kobe Steel, Ltd. Takasago Factory

Claims (5)

[Claims] When a powder containing a mixed powder or a fine powder is charged into a storage tank having a square cylindrical portion, the powder is mixed with an umbrella-shaped structure provided in the cylindrical portion of the storage tank. And a powder introduction method for preventing powder separation, wherein the powder is guided from the point of introduction of the powder to an inner wall surface of a corner portion of a storage tank and dropped. 2. The method according to claim 1, wherein the powder is a mixed powder for powder metallurgy. 3. A storage tank comprising a prismatic cylindrical portion, in which a powder inlet is provided at an upper part of the cylindrical part and a powder outlet is provided at a lower part thereof, wherein a pyramid and a pyramid are provided in the cylindrical part of the storage tank. An umbrella-shaped structure comprising an inclined portion further provided on a lower side of the umbrella-shaped structure, a vertex of a pyramid of the umbrella-shaped structure is directly below the powder inlet, and a lower end of the inclined portion is a lower side of the pyramid. A powder having an umbrella-shaped structure, further extending toward the corner inner wall surface side of the cylindrical portion of the storage tank, guiding the powder from the charging point to the inner wall surface of the corner portion of the cylindrical portion of the storage tank, and dropping the powder. Storage tank to prevent separation. 4. A storage tank having an umbrella-like structure according to claim 3, which is used for a powder mixture for powder metallurgy. 5. The method according to claim 3, which is used when a funnel flow occurs when the powder is discharged from the powder outlet after the powder is charged. Storage tank.