JP2009101312A - Method and apparatus for classifying powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for classifying powder advantageous in accurately and easily classifying powder having difficulty in classification conventionally. <P>SOLUTION: The method for classifying powder 10 includes: a container 12; a powder supply part 14; a powder recovery part 16; a liquid medium supply part 18; a liquid medium discharge part 20; an agitation part 22; an upper rectification part 24A; and a lower rectification part 24B, or the like. The container 12 forms a housing space S for housing a liquid medium 2. The powder supply part 14 transfers the powder 3 to be classified from the outside of the container 12 to the liquid medium part located below the housing space S. The powder recovery part 16 recovers the powder 3 floated in the liquid medium 2 and moved to the liquid medium part located above the housing space S out of the powder 3 transferred to the liquid medium part from the powder supply part 14, and takes it outside of the container 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a powder classification method and a powder classification apparatus.

Distinguishing powders by their particle size and density is called classification.
As a powder classification method, for example, a method using a sieve or a method using a difference in the sedimentation rate of powder in a liquid medium (water) is known (see Patent Document 1).
JP 2004-113962 A

However, in the case of a powder having poor fluidity and a true density of 1 g / cc or less (specific gravity of 1 or less), it is difficult to apply the conventional classification method described above.
For example, when a powder having poor fluidity is classified using a sieve, the sieve causes clogging, which is disadvantageous in improving classification efficiency.
The method using the difference in sedimentation speed is based on the premise that the specific gravity of the powder to be classified is larger than 1, in other words, the powder is submerged in the liquid medium (water). Cannot be classified (powder having a true density of 1 g / cc or less).
In theory, it is possible to classify a powder having a specific gravity of 1 or less if a liquid medium having a true density lower than that of water is used. However, there is an appropriate liquid medium that is inexpensive and easy to handle. Therefore, it is not practical to use the difference in sedimentation speed as a classification method for powders having a specific gravity of 1 or less.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a powder classification method and a powder classification that are advantageous in accurately and easily performing classification of powders that have been difficult to classify conventionally. To provide an apparatus.

In order to achieve the above-mentioned object, the powder classification method of the present invention stores a liquid medium in a storage space extending up and down of a container, and the powder to be classified is placed in a liquid medium portion located below the storage space. The powder transferred to the liquid medium part is floated in the liquid medium, and the powder moved to the liquid medium part located in the upper part of the accommodation space is collected and taken out.
Further, the powder classification apparatus of the present invention includes a container that forms a storage space extending vertically, a liquid medium stored in the storage space, and a powder to be classified from the outside of the container in the storage space. A powder supply unit that transfers to a liquid medium part located in the lower part, and of the powder transferred from the powder supply part to the liquid medium part, floats in the liquid medium and is located in the upper part of the accommodation space And a powder recovery unit that recovers the powder that has moved to the liquid medium portion and takes it out of the container.

  According to the present invention, since the powder floating in the liquid medium is collected, it is advantageous in classifying a powder having a lighter specific gravity than a liquid medium that has been difficult to classify conventionally.

(First embodiment)
Next, a powder classification method and a powder classification apparatus according to embodiments of the present invention will be described with reference to the drawings.
First, the floating speed of the powder in the liquid medium, which is a premise in the method and apparatus of the present invention, will be described.
The settling velocity V of the powder in the powder (solid) that settles when placed in the liquid medium, that is, the powder medium whose specific gravity is heavier than that of the liquid medium, is expressed by the stokes equation (1).

Where ρ _p is the true density of the powder (solid true density), ρ ₀ is the liquid density, D _p is the diameter of the particles constituting the powder (solid diameter), μ is the liquid viscosity, and g is the gravitational acceleration.
According to the formula (1), it can be seen that the powder has a higher sedimentation speed V as the particle diameter is larger, and the sedimentation speed V is faster as the true density of the powder is larger.

  In contrast to the above formula (1), the floating speed V of the powder in the powder (solid) that floats when placed in the liquid medium, that is, the powder medium having a specific gravity lighter than that of the liquid medium is expressed by the formula (2). This equation (2) is derived by setting the sign of the liquid resistance force in the equation of motion when deriving the Stokes equation of equation (1) to the opposite sign.

  According to the equation (2), it can be seen that the powder has a faster floating speed V as the particle diameter is larger, and a higher floating speed V as the powder has a lower true density.

FIG. 2 is a schematic diagram showing the behavior of powder particles in the liquid medium, and specifically describes the expression (2).
As shown in FIG. 2, when a powder having a specific gravity lower than that of the liquid medium 2 is put in the liquid medium 2, each of the particles 4 constituting the powder floats at a flying speed V as indicated by an arrow. That is, the direction of the arrow indicates the moving direction of the particle 4, and the length of the arrow indicates the magnitude of the flying speed V.
In the present embodiment, the liquid medium 2 is water, and the liquid density is 1 g / cc.
The powder is composed of particles 4 having a specific gravity lighter than that of the liquid medium 2, and specifically, particles having an average particle diameter (average diameter) of several tens of microns generally called glass microballoons or glass hollow spheres. It consists of Examples of such glass microballoons include Glass Bubbles (registered trademark of Sumitomo 3M Limited).
In this case, of the particles 4, ascent rate of diameter D _p is large (or true density [rho _p is small) particles 4A, from the ascent rate V of diameter D _p is small (or true density [rho _p is large) particles 4B Is also getting bigger.
Further, among the particles 4, the particles 4 </ b> C whose specific gravity caused by manufacturing variation or the like is heavier than the specific gravity of the liquid medium 2 settles in the liquid medium 2.
Further, since the fragments 6 generated by the breakage of the glass microballoon are not hollow, the specific gravity is heavier than the specific gravity of the liquid medium 2, and therefore settles in the liquid medium 2.
Accordingly, the powder particles 4 placed in the liquid medium 2 are divided into the floating particles 4 (4A, 4B), the sedimenting particles 4 (4C), and the debris 6, so that only the floating particles 4 are collected. Of course, it is possible to classify the powder, and as shown in the above formula (2), there is a difference in the size of the diameter D _{p of the} particles 4 and the true density ρ _p of the powder. Since it is reflected in the flying speed V of the powder particles 4 in the liquid medium 2, if the powder particles are selected based on the flying speed V, the powder can be classified more precisely.
That is, the method and apparatus of the present invention classify powder based on the floating velocity V of the powder particles 4 in the liquid medium 2 represented by the formula (2), which will be described in detail below. To do.

FIG. 1 is an explanatory view showing a configuration of a powder classification apparatus 10 according to the present embodiment. A powder classification method according to an embodiment of the present invention will be described together with the powder classification apparatus 10.
The powder classifier 10 includes a container 12, a powder supply unit 14, a powder recovery unit 16, a liquid medium supply unit 18, a liquid medium discharge unit 20, a stirring unit 22, an upper rectification unit 24A, The lower rectification unit 24B and the like are included.
The container 12 forms an accommodation space S for accommodating the liquid medium 2.
The accommodation space S extends in the vertical direction with a uniform cross section, and in this embodiment, the side wall 12A extending vertically, the bottom wall 12B closing the lower part of the side wall 12A, and the upper part closing the upper part of the side wall 12A. And a wall 12C.
The accommodation space S may be circular or rectangular when viewed in plan, and its shape is arbitrary.

In the accommodation space S, the liquid medium 2 is accommodated, and among the liquid medium portions accommodated in the accommodation space S, the upper liquid medium portion 2A is the upper liquid medium portion and the lower liquid medium portion is the lower portion. The liquid medium part 2B is used, and the liquid medium part positioned between the upper liquid medium part 2A and the lower liquid medium part 2B is called the intermediate liquid medium part 2C.
In the present embodiment, a gap is secured between the liquid surface 202 of the liquid medium 2 and the upper wall 12C, the liquid medium 2 is water, and the liquid density ρ ₀ is 1 g / cc.

The powder supply unit 14 transfers the powder 3 to be classified from the outside of the container 12 to the liquid medium part located in the lower part of the accommodation space S, that is, the lower liquid medium part 2B. In the drawing, reference numeral 14A denotes a powder transfer pipe provided through the side wall 12A and extending between the powder supply unit 14 and the lower liquid medium unit 2B.
The powder supply unit 14 supplies the powder to the lower liquid medium unit 2B in a slurry state by mixing the powder with the same liquid medium as the liquid medium 2 in advance.
When the powder 3 is in the form of a slurry in this way, bubbles can be prevented from mixing with the powder 3 and the particles 4 from floating together with the bubbles, so that the influence of the bubbles on the rising speed V of the particles 4 can be eliminated. This is preferable for accurately performing the classification.

The powder recovery unit 16 floats in the liquid medium 2 out of the powder 3 transferred from the powder supply unit 14 to the liquid medium part, and moves to the liquid medium part located above the accommodation space S. Is recovered and taken out of the container 12.
In the present embodiment, the powder recovery unit 16 recovers the powder 3 through the opening 12D provided in the side wall 12A facing the liquid surface 202 of the liquid medium 2.

The liquid medium supply unit 18 supplies the liquid medium 2 at a constant flow rate from above the liquid surface 202 of the liquid medium 2, onto the liquid surface 202, or to the upper end of the upper liquid medium unit 2A.
Reference numeral 18A in the figure denotes a liquid medium supply pipe provided through the upper wall 12C across the liquid medium supply unit 18 and the accommodation space S. In the present embodiment, the liquid medium supply unit 18 is a pipe 18A. The liquid medium 2 is supplied onto the liquid surface 202 via
In addition, various methods, such as performing supply of the liquid medium 2 by the liquid medium supply part 18 so that it may pour down on a shower over the whole upper part of the accommodation space S, can be considered, and the flow toward the downward direction of the liquid medium 2 is equalized in short. Should be able to.

The liquid medium discharge unit 20 discharges the liquid medium 2 from the lower part of the accommodation space S at a constant flow rate.
In the present embodiment, the liquid medium discharge unit 20 includes a discharge port 20A provided in the center of the bottom wall 12B, and an inclined bottom plate 20B that is connected to the discharge port 20A and becomes higher as the distance from the discharge port 20A increases. The bottom of the accommodation space S is partitioned by a bottom plate 20B.
The liquid medium discharge section 20 and the liquid medium supply section 18 are designed so that the liquid medium 2 flows at a constant flow rate from the upper side to the lower side over almost the entire area of the accommodation space S.
In the present embodiment, the liquid medium supply section 18 and the liquid medium discharge section 20 constitute a liquid medium descending flow generation section as claimed in the claims.

The agitation unit 22 agitates the liquid medium 2 and is provided in the intermediate liquid medium unit 2C.
In the present embodiment, the stirring unit 22 has a stirring blade 22A, and the stirring blade 22A is connected to the lower end of the rotating shaft 22B disposed through the upper wall 12C, and is on the upper wall 12C. The rotary drive source (not shown) of the rotary shaft 22B is connected, and the intermediate liquid medium part 2C is stirred by rotating the stirring blade 22A via the rotary shaft 22B by the rotary drive source.
By stirring the intermediate liquid medium part 2C by the stirring part 22, the particles 4 constituting the powder 3 located in the intermediate liquid medium part 2C are agitated, so that the particles 4 adhering to each other can be separated from each other, or Separation of the sticking particles 4 and the fragments 6 is achieved. For this reason, it is advantageous in classifying the powder 3 having the property of being easily aggregated (prone to lumps) with high accuracy.

The upper rectification unit 24A and the lower rectification unit 24B are provided above and below the stirring unit 22, respectively, to adjust the flow of the liquid medium 2.
In the present embodiment, the upper rectification unit 24A and the lower rectification unit 24B are provided to extend over the entire space of the accommodation space S when viewed in plan, and penetrate in the vertical direction and are sufficiently larger than the diameter of the particles 4 It has a so-called honeycomb structure in which a large number of holes having a large inner diameter are formed.
As the liquid medium 2 flows through a number of holes formed in the upper rectifying unit 24A and the lower rectifying unit 24B, a vortex generated when the intermediate liquid medium unit 2C is stirred by the stirring unit 22 is generated from the intermediate liquid medium unit 2C. Transmission to both the upper liquid medium part 2A and the lower liquid medium part 2B is prevented, whereby the flow of the liquid medium 2 is adjusted.

Next, the operation of the powder classifier 10 will be described.
It is assumed that the liquid medium 2 is stored in the storage space S in advance.
Here, a certain amount of the liquid medium 2 is supplied from the liquid medium supply unit 18 to the liquid medium 2 in the accommodation space S, and at the same time, the certain amount of the liquid medium 2 is discharged from the liquid medium discharge unit 20. liquid medium 2 in the accommodation space S flows downward from above at a constant flow rate V _0.
In this state, when the slurry-like powder 3 is supplied from the powder supply unit 14 to the lower liquid medium unit 2B, the particles 4 constituting the powder 3 float or settle in the liquid medium 2.
That is, from the relationship between the flying speed V and the flow velocity V ₀ of the liquid medium 2 according to the above-described equation (2),
The particles 4 satisfying V <V ₀ settle in the liquid medium 2, reach the bottom plate 20 </ b> B, move downward along the bottom plate 20 </ b> B, and are discharged from the liquid medium discharge unit 20.
The particles 4 satisfying V = V ₀ do not float or settle in the liquid medium 2 and remain in the lower liquid medium portion 2B.

The particles 4 satisfying V> V ₀ float along the flow of the liquid medium 2, pass through the intermediate liquid medium part 2 C from the lower liquid medium part 2 B, reach the upper liquid medium part 2 A, and are collected by the powder recovery unit 16. Collected.
In other words, only the powder 3 having a flying velocity V larger than the flow velocity V _{0 of the} liquid medium 2 (in other words, only the powder 3 floating in the liquid medium 2 against the flow of the liquid medium 2) is upper. It is recovered from the liquid medium part 2A.
Further, even when the plurality of particles 4 float up in a state where they are stuck together, the particles 4 are forcibly separated by the stirring of the liquid medium 2 by the stirring unit 22. Based on the relationship of _0, the particles 4 to be levitated rise, and the particles 4 to be settled settle in the liquid medium 2 and are discharged from the liquid medium discharge unit 20.
Moreover, even if the particles 6 to be levitated are floated in a state where the fragments 6 are stuck, the fragments 6 are forcibly separated from the particles 4 by the stirring of the liquid medium 2 by the stirring unit 22, so that the particles 4 to be levitated are As a result, the debris 4 settles in the liquid medium 2 and is discharged from the liquid medium discharge portion 20.

As described above, according to the present embodiment, the powder 3 to be classified is placed in the lower part of the storage space S in a state where the liquid medium 2 is flowed from the upper side to the lower side in the storage space S at a constant flow rate. The powder 3 that has been transferred to the liquid medium part that is located, floats in the liquid medium 2 out of the powder 3 that has been transferred to the liquid medium part, and moves to the liquid medium part that is located above the accommodation space S, that is, Since only the powder 3 having a flying speed V higher than the flow speed V ₀ of the liquid medium 2 is collected and taken out, the powder 3 floating in the liquid medium 2 that has been difficult to classify conventionally. This is advantageous in accurately and easily classifying.

In the present embodiment, the powder 3 is classified by collecting only the powder 3 having a flying velocity V higher than the flow velocity V ₀ of the liquid medium 2. Therefore, strictly speaking, classification based on the particle diameter D _p of the particles 4 constituting the powder 3 or the true density ρ _p of the particles 4 itself is not performed.
However, for example, the case of the classification to the powder 3 (particles 4) glass microballoons should, larger particle diameter D _p is greater true density [rho _p, conversely, those particle diameter D _p is small true density [rho _Since there is a correlation that _{p is} also small, classification based on the relationship of the flying speed V shown in the formula (2), that is, powder having a flying speed V larger than the flow speed V ₀ of the liquid medium 2 By collecting only the body 3, it is possible to perform classification with high accuracy substantially based on the particle diameter D _p of the particles 4 and the true density ρ _p of the particles 4.
Thus, correlation of the particle diameter D _p and the true density [rho _p of the powder to be classified is be the same as the correlation between the particle diameter D _p and the true density [rho _p of glass microballoons, using the present invention method and apparatus Therefore, classification can be performed with high accuracy.

Further, in the present embodiment, the case has been described in which the powder 3 is classified in a state in which the flow of the liquid medium 2 from the upper side to the lower side is generated at a constant flow velocity V ₀ .
However, the flow of the liquid medium 2 is not generated, the particles 4 having a specific gravity lighter than that of the liquid medium 2 are levitated, and the particles 4 and the fragments 6 having a specific gravity heavier than that of the liquid medium 2 are levitated. The powder 3 may be classified by collecting only the particles 4. In this case, the powder 3 having a lighter specific gravity than the liquid medium 2, which is difficult to classify conventionally, is classified. It will be advantageous.

In addition, the provision of the agitation unit 22 is advantageous in classifying the powder 3 having the property of being easily agglomerated (prone to lumps) with high accuracy, but the agitation unit 22 may be omitted.
Even when the stirring unit 22 is not provided, if the rectifying unit such as the upper rectifying unit 24A or the lower rectifying unit 24B is provided, the flow velocity V ₀ of the liquid medium 2 can be stabilized, and therefore the powder 3 This is advantageous for improving classification accuracy.

(Second Embodiment)
Next, a second embodiment will be described.
The second embodiment is a modification of the first embodiment, and is different from the first embodiment only in that an ultrasonic vibration unit is provided instead of the stirring unit 22 of the first embodiment. is doing.
FIG. 3 is an explanatory diagram of the powder classification apparatus 10 according to the second embodiment. In the following embodiments, the same parts as those in the first embodiment are not illustrated or simply denoted by the same reference numerals, and the differences will be mainly described.
In the second embodiment, the ultrasonic vibration is applied to the powder 3 in the intermediate liquid medium part 2C by providing the ultrasonic vibration part 30 that generates ultrasonic vibration in the intermediate liquid medium part 2C. .
The ultrasonic vibration is applied to the intermediate liquid medium part 2C, whereby the particles 4 constituting the powder 3 located in the intermediate liquid medium part 2C are vibrated, thereby separating the particles 4 adhering to each other, or Separation of the particles 4 and the debris 6 adhering to each other is achieved.
According to the second embodiment, it is needless to say that the same effects as those of the first embodiment can be obtained. In particular, the powder 3 having the property of being easily agglomerated (prone to become lumpy) is classified with high accuracy. The advantageous effect is obtained.

(Third embodiment)
Next, a third embodiment will be described.
In the third embodiment, the path through which the floating powder 3 (particle 4) is guided and the path through which the settled powder 3 (particle 4) is guided are separated.
FIG. 4 is an explanatory diagram of the powder classifier 10 of the third embodiment.
The powder classifier 10 includes a powder supply unit 14, a powder recovery unit 16, a liquid medium supply unit 18, and a liquid medium discharge unit 20, as in the first embodiment.
That is, the powder supply unit 14 transfers the powder 3 to be classified from the outside of the container 12 to the liquid medium portion located in the lower part of the storage space S.
The powder recovery unit 16 floats in the liquid medium 2 out of the powder 3 transferred from the powder supply unit 14 to the liquid medium part, and moves to the liquid medium part located above the accommodation space S. Is recovered and taken out of the container 12.
The liquid medium supply unit 18 supplies the liquid medium 2 at a constant flow rate from above the liquid surface 202 of the liquid medium 2 or on the liquid surface 202 or to the upper end of the upper liquid medium unit 2A via the pipe 18A. To do.
The liquid medium discharge unit 20 discharges the liquid medium 2 from the lower part of the accommodation space S at a constant flow rate. The liquid medium discharge unit 20 includes a discharge port 20A provided at the center of the bottom wall 12B of the container 12. The inclined bottom plate 20B is connected to the discharge port 20A and becomes higher as the distance from the discharge port 20A increases.

In the third embodiment, a path separation unit 40 is provided in the accommodation space S of the container 12, and a powder recovery guide plate 50 is provided on the upper part of the path separation unit 40 (upper part of the accommodation space S). Yes.
The powder collecting guide plate 50 may be omitted and the powder may be collected by the same method as in the first embodiment. However, when the powder collecting guide plate 50 is provided, a path separation unit 40 described later is provided. This is advantageous in efficiently recovering the powder 3 passing through the path Lu formed by the above.
The path separation unit 40 is configured by three path separation members 41 arranged one above the other.
The accommodation space S has a columnar shape, and thus the side wall 12A has a cylindrical shape. Each path separation member 41 includes a first member 42 and a second member 44, and the first member 42 and the second member 44 are It is arranged coaxially with the accommodation space S.
The first member 42 includes a truncated conical guide portion 42A whose diameter gradually increases as it goes upward, and a cylindrical portion 42B connected to the lower end opening of the guide portion 42A and extending downward.
The second member 44 has a truncated cone shape whose diameter gradually decreases as it goes upward, and its upper end 44A is located near the upper end of the cylindrical portion 42B and is coaxially arranged with the cylindrical portion 42B, and the lower end 44B is It is located at a location close to the cylindrical side wall 12A at a location near the bottom of the cylindrical portion 42B.

The lower end of the cylinder part 42B of the first member 42 arranged at the highest position is located immediately above the lower end opening of the first member 42 arranged in the middle.
Further, the lower end 44B of the second member 44 arranged at the highest position is located outside and below the upper end of the guide portion 42A of the first member 42 arranged in the middle.
Moreover, the lower end of the cylinder part 42B of the 1st member 42 arrange | positioned in the middle is located just above the lower end opening of the 1st member 42 arrange | positioned lowest.
Further, the lower end of the second member 44 arranged in the middle is located outside the upper end of the guide portion 42A of the first member 42 arranged at the lowest position and at a lower position.
Further, the lower end of the cylindrical portion 42B of the first member 42 arranged at the lowest position is located above the discharge port 20A.
Further, the lower end of the second member 44 arranged at the lowest position is located at a location above the upper end of the bottom plate 20B.

The powder recovery guide plate 50 has a truncated conical shape whose diameter decreases toward the top, and is provided with an upper opening 50A in the upper part and a lower opening 50B in the lower part.
The lower opening 50B of the powder collection guide plate 50 is located outside and below the guide portion 42A of the first member 42 of the path separation member 41 located at the uppermost position.

Therefore, the liquid medium 2 flows from the upper side to the lower side in the accommodation space S, and the powder 3 that floats in the liquid medium 2 against this flow is divided into three path separating members 41 as indicated by broken arrows in the figure. The second member 44 floats along a path Lu along the inner surface of the second member 44 and the outer surface of the guide portion 42A of the first member 42, and eventually moves along the inner surface of the powder recovery guide plate 50 and then recovers to the powder recovery portion 16. Is done.
On the other hand, the settled powder 3 settles in a path Ld1 passing through the inner surface of the guide part 42A of the first member 42 of the three path separation members 41 and the inside of the cylindrical part 42B, as indicated by the two-dot chain line arrows in the figure. At the same time, as indicated by the one-dot chain line arrow in the figure, it settles down along a path Ld2 passing through a location outside the three path separating members 41 in the radial direction and inside the inner surface of the side wall 12A to reach the bottom plate 20B and along the bottom plate 20B. Then, it moves downward and is discharged from the liquid medium discharge unit 20 soon.

  According to the third embodiment, it is needless to say that the same effects as those of the first embodiment can be obtained, and the route Lu through which the floating powder 3 (particles 4) are guided and the settled powder. Since the paths Ld1 and Ld2 through which 3 (particles 4) are guided are separated, the smooth movement (floating) of the powder 3 is hindered by the collision between the powder 3 that floats and the powder 3 that settles. Therefore, the time required for the powder 3 to float can be shortened, which is advantageous in reducing the time required for classifying the powder 3 and improving the efficiency.

In the embodiment, the case where the powder 3 to be classified is a glass microballoon has been described. However, the method and apparatus of the present invention has a specific gravity that is lighter than that of the liquid medium 2 and floats in the liquid medium 2. What kind of powder is classified is arbitrary. For example, powders such as phenol microballoons and polyethylene resins can be classified.
Further, in the present embodiment, the case where the liquid medium 2 is water has been described. However, the liquid medium 2 may be any one as long as the powder 3 to be classified floats, and what is used as the liquid medium 2? Is optional.

It is explanatory drawing which shows the structure of the powder classification apparatus 10 of this Embodiment. It is a schematic diagram which shows the behavior of the particle of the powder in a liquid medium. It is explanatory drawing of the powder classification apparatus 10 of 2nd Embodiment. It is explanatory drawing of the powder classification apparatus 10 of 3rd Embodiment.

Explanation of symbols

  2 ... Liquid medium, 3 ... Powder, 12 ... Container, 14 ... Powder supply unit, 16 ... Powder recovery unit, S ... Storage space.

Claims (17)

The liquid medium is accommodated in a storage space extending above and below the container,
The powder to be classified is transferred to the liquid medium part located in the lower part of the housing space,
Collecting and taking out the powder that floated in the liquid medium and moved to the liquid medium part located in the upper part of the housing space out of the powder transferred to the liquid medium part,
The powder classification method characterized by the above-mentioned. The liquid medium flows at a constant flow rate from above to below in the accommodation space while being supplied in a constant amount to the upper portion of the accommodation space and discharged from the lower portion of the accommodation space.
The powder classification method according to claim 1. Agitating the liquid medium in an intermediate portion in the vertical direction of the liquid medium accommodated in the accommodation space;
The powder classification method according to claim 1 or 2, wherein Stirring the liquid medium in an intermediate portion in the vertical direction of the liquid medium accommodated in the accommodation space,
The flow of the liquid medium is adjusted at either one or both of the upper part and the lower part of the part to be stirred.
The powder classification method according to claim 3. Transfer of the powder to the liquid medium part located in the lower part of the storage space is made in a slurry state by mixing the powder with the same liquid medium as the liquid medium in advance.
The powder classifier according to claim 1, wherein: A container forming a storage space extending vertically;
A liquid medium accommodated in the accommodating space;
A powder supply unit for transferring powder to be classified from the outside of the container to a liquid medium portion located in a lower portion of the storage space;
Out of the powder transferred from the powder supply unit to the liquid medium part, the powder that floats in the liquid medium and moves to the liquid medium part located in the upper part of the accommodation space is recovered to the outside of the container A powder recovery unit to be taken out
A powder classifier. In the housing space, a liquid medium descending flow generation unit that generates a flow in which the liquid medium flows at a constant flow rate from above to below is provided.
The powder classification apparatus according to claim 6. The liquid medium downward flow generation unit is
A liquid medium supply unit that supplies the liquid medium to the upper part of the housing space at a constant flow rate;
A liquid medium discharge part configured to discharge the liquid medium from the lower part of the housing space at the constant flow rate,
The powder classifier according to claim 7. Among the liquid medium parts accommodated in the accommodating space, the liquid medium part located at the upper part is the upper liquid medium part, the liquid medium part located at the lower part is the lower liquid medium part, and the upper liquid medium part and the When the liquid medium part located between the lower liquid medium part is an intermediate liquid medium part, the intermediate liquid medium part is provided with a stirring part for stirring the liquid medium,
The powder classifier according to claim 6 or 7, Among the liquid medium parts accommodated in the accommodating space, the liquid medium part located at the upper part is the upper liquid medium part, the liquid medium part located at the lower part is the lower liquid medium part, and the upper liquid medium part and the When the liquid medium part located between the lower liquid medium part is an intermediate liquid medium part, the intermediate liquid medium part is provided with a stirring part for stirring the liquid medium,
A rectifying unit for adjusting the flow of the liquid medium is provided on either or both of the upper side and the lower side of the stirring unit.
The powder classifier according to claim 7. Among the liquid medium parts accommodated in the accommodating space, the liquid medium part located at the upper part is the upper liquid medium part, the liquid medium part located at the lower part is the lower liquid medium part, and the upper liquid medium part and the When the liquid medium part located between the lower liquid medium part is an intermediate liquid medium part, an ultrasonic vibration part that generates ultrasonic vibrations in the intermediate liquid medium part is provided.
The powder classifier according to claim 6 or 7, In the housing space, a path separation unit that separates the path between the floating powder and the settled powder is provided.
The powder classifier according to claim 1, wherein: The container has a cylindrical side wall;
The accommodating space has a cylindrical shape,
The path separating portion is configured by arranging a plurality of path separating members vertically on the same axis as the accommodating space,
Each of the path separating members includes a first member and a second member,
The first member is composed of a truncated conical guide portion whose diameter gradually increases as it goes upward, and a cylindrical portion connected to the lower end opening of the guide portion and extending downward,
The second member has a truncated conical shape whose diameter gradually decreases as it goes upward, and its upper end is located near the upper end of the cylindrical portion and is coaxial with the cylindrical portion, and the lower end is the cylindrical portion Located at a location near the side wall at a location near the bottom of the part,
The path separating member adjacent to the upper side is disposed such that the lower end of the cylindrical portion of the first member disposed on the upper side is located immediately above the lower end opening of the first member disposed on the lower side, and is disposed on the upper side. The lower end of the second member is disposed so as to be located outside and below the upper end of the guide portion of the first member disposed on the lower side,
The path of the floating powder is a path along the inner surface of the second member and the outer surface of the guide portion of the first member,
The path of the settled powder includes a path that passes through the inner surface of the guide portion and the inside of the cylindrical portion of the first member, and a path that passes through a location radially outside the path separating member and inside the inner surface of the side wall. Is,
The powder classifier according to claim 12, wherein Supply of the powder to the lower liquid medium part by the powder supply unit is made in a slurry state by previously mixing the powder with the same liquid medium as the liquid medium,
The powder classification apparatus according to claim 6. The true density of the liquid medium is approximately 1 g / cc.
The powder classification apparatus according to claim 6. The liquid medium is water;
The powder classification apparatus according to claim 6. The powder is a hollow glass sphere,
The powder classification apparatus according to claim 6.

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