JPH1015429A - Wet classifier and method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the recovery work of particles of layer structure once formed easy by equipment of relatively simple structure. SOLUTION: A wet classifier using sedimentation by gravity is provided with in upright classifying cylinder 1, an inflow pipe 3 for causing classifying liquid to flow in fitted to the lower end of the classifying cylinder 1, and a particle recovery pipe 20 inserted into the classifying cylinder 1 at the head part thereof and also formed movably up and down inside the classifying cylinder 1. By keeping classifying liquid flowing in from the inflow pipe 3 at an almost fixed flow rate, and upflow having the same velocity as the sedimentation one of granular substances is made to form layer structure according to the particle diameter inside the classifying cylinder 1. While the flow rate of the classifying liquid is kept about fixed, successively the recovery pipe 20 is moved from the upper position to the lower position in order, causing particles to be recovered through the recovery pipe 20 in order from those present in the upper layer of the layerlike structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for so-called wet classification in which solid particles are separated in a liquid by utilizing sedimentation caused by gravity, and more particularly, to greatly reduce a recovery operation. The present invention relates to a wet classification apparatus and a wet classification method.

[0002] Specifically, there is an apparatus and a method for separating particles of qualitatively uniform but different sizes according to their sizes. For example, they are made of glass or synthetic resin and have a diameter of about several micrometers. It is used in the process of producing spherical beads precisely aligned with certain values. The beads classified in this manner are used as a gap control material for a liquid crystal display panel, standard particles, a filler for analysis, a carrier for a diagnostic agent, various labeling materials, and the like.

[0003]

2. Description of the Related Art Processes of wet classification include those using an upward flow, those using a horizontal flow, those using a simple stationary method, and the like. Things.

[0004] In addition, the method using the upward flow is based on a batch operation (one in which particles charged at a time are successively taken out) and a continuous operation (one in which continuously supplied particles are continuously taken out). It is roughly divided into cases.

FIG. 9 shows a basic form of a classifier using a rising flow and a batch operation.

That is, FIG. 9 shows that the classification liquid inlet 62 is provided at the lower part of the classification cylinder 61 and the slurry outlet 6 containing fine particles
Reference numeral 3 denotes a structure in which a slurry supply port 64 is provided in the upper part of the classification cylinder 61 and a slurry supply port 64 is provided in the middle of the classification cylinder 61.

The slurry supplied from the supply port 64 is often denser than the slurry retained in the apparatus. Therefore, the supply port 64 is often provided near the upper end of the classification cylinder 61 in order to disperse the supplied slurry in the classification liquid in the classification cylinder 61 well.

Usually, a liquid having a lower density than the particles to be classified is used as the classification liquid. The particles to be classified are in the classification liquid and settle down by the action of gravity, and therefore move downward relative to the classification liquid, but the classification liquid continuously flows from the inlet 62 at the lower part of the classification cylinder 61. Since the liquid is supplied and moves upward in the classification cylinder 61, the rise of the classification liquid and the sedimentation of the particles are offset, and the slurry-like particles stay in the classification cylinder 61 for a relatively long time.

In this case, the sedimentation speed of the slurry-like particles supplied into the classification cylinder 61 depends on the particle size, and the coarser particles sediment faster. That is, in comparison with the ascent rate of the classification liquid, the components that settle faster (coarse particles) move downward, and the particles that do not settle (fine particles) move upward.

As a result, in the classification cylinder 61, a layer having a larger diameter is formed in a lower layer corresponding to the diameter of the particle. At this time, the layered structure is affected by the supply and discharge of the classification liquid. It is necessary that the structure is not disturbed.

As a device satisfying such requirements, for example, a classifier described in Japanese Patent Publication No. 54-20028 (hereinafter referred to as prior art 1), a classifier disclosed in Japanese Patent Publication No. 59-292, and the like.
No. 99 gazette (this is described in Related Art 2
There is).

[0012] The classification device of the prior art 1 has a lower part of the main body,
A plate-like member having a large number of small-diameter holes is mounted, and a block having a plurality of vertical through-holes whose total opening area is smaller than the flow path cross-sectional area of the main body is provided below the member. A plate-shaped member having a large number of small-diameter holes is attached to the lower portion, and further, in each vertical through-hole portion of the block,
It has a structure in which a support member having a particle size slightly larger than the hole provided in the plate-like member is housed in a flowable manner.

In the classification device of the prior art 2, a plurality of lattice tubes are mounted in the classification tube in the longitudinal direction of the classification tube at intervals, and a wall between the vertically adjacent lattice tubes (the classification tube). (Wall surface) is provided with a resin outlet.

[0014]

By the way, if the flow rate of the classification liquid is gradually increased, the layered structure rises as a whole and flows out of the slurry 63 from the upper part in order, and is condensed to collect particles. It is possible.

However, when the flow rate of the classification liquid is increased, the order inside the classification cylinder is disturbed. Therefore, the rate of increasing the flow rate (the flow rate increase per time) must be very slow. In general, the time required to recover most of the particles while increasing the flow rate usually exceeds the period for forming a layered structure of the slurry. Therefore, if the layered particles can be collected without increasing the flow rate, the collection time can be significantly reduced.

In the above-mentioned prior art 2, this problem is solved by providing a large number of resin outlets on the wall of the classification tower, but the structure of the entire apparatus is complicated.

The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a relatively simple structure, which can greatly reduce the work of collecting particles having a layered structure once formed. An object of the present invention is to provide a wet classification apparatus and a wet classification method.

[0018]

According to a first aspect of the present invention, there is provided a wet classification apparatus utilizing sedimentation caused by gravity, comprising: an upright cylindrical classification cylinder; And an inflow means provided at the lower end of the classification cylinder for inflowing the classification liquid, and a collection of particles whose tip is inserted inside the classification cylinder and which is provided to be vertically movable inside the classification cylinder. And a tube.

Further, in the wet classification method according to a second aspect of the present invention, there is provided a classification cylinder having an upright cylindrical shape, an inflow means provided at a lower end of the classification cylinder for allowing a classification liquid to flow, and a tip end portion of the classification. In a wet classification device using sedimentation due to gravity, which is inserted into a cylinder and has a collection pipe for particles provided to be vertically movable inside the classification cylinder,
By maintaining the classification liquid flowing from the inflow means at a substantially constant flow rate, an ascending flow having the same speed as the sedimentation speed of the granular material is created,
After forming a layered structure according to the particle diameter inside the classification cylinder, while continuously maintaining the flow rate of the classified liquid substantially constant, by sequentially moving the collection tube from the upper position to the lower position, the layered structure of the layered structure through the collection tube The particles are collected in order from the upper layer.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 5 shows the basic structure of the wet classification device of the present invention.

That is, an inverted conical end plate portion 2 is formed continuously from the lower end side opening edge 1a of the classifying cylinder 1 which stands upright.
A classification liquid inflow pipe 3 provided with an inflow means 3c is provided on the bottom 2a of the end plate portion 2, and an outflow pipe 4 is provided on the upper end 1b side of the classification cylinder 1. Further, a mixing section 10 for mixing the classification liquid and the granular material is provided inside the classification cylinder 1 and above the inflow pipe 3.

FIGS. 1 to 4 show embodiments of a wet classifier according to the present invention.

The wet classification device shown in FIG. 1 is different from the wet classification device shown in FIG. 5 in that the outflow pipe 4 is eliminated, and instead, the tip is inserted into the upper end 1b of the classification tube 1 and inside the classification tube 1. In which a recovery pipe 20 is provided. The insertion port of the collection pipe 20 formed at the upper end 1 b of the classification cylinder 1 is sealed by a seal member 201. Also, the collection pipe 20
Is provided so as to be slidable with respect to the seal member 201, and is therefore provided so as to be vertically movable inside the classification tube 1.

The wet classifier shown in FIG. 2 is the same as the wet classifier shown in FIG. 5, except that a collection tube 20 having a tip inserted into the classification tube 1 is provided at the upper end 1b of the classification tube 1. It is. The recovery pipe 20 has the same configuration as that shown in FIG. 1 and is provided to be vertically movable inside the classification tube 1. Also, by connecting the flexible tube 21 to the end of the collection tube 20,
The pressure difference between the two outlets of the recovery pipe 20 and the outflow pipe 4 does not change even if the pipe moves up and down. However, it is not necessary to connect the flexible tube 21 if the outflow pipe 4 is closed at the time of collecting the particles and is used only for periodic degassing.

In the wet type classification device shown in FIG. 3, a collection pipe 20 having a tip inserted into the classification cylinder 1 is provided at the upper end 1b of the classification cylinder 1, and the outlet pipe 4 is connected to the side wall of the classification cylinder 1. It is provided at the top. The recovery pipe 20 has the same configuration as that shown in FIG. 1, and is provided to be vertically movable inside the classification tube 1.

The wet classifier shown in FIG. 4 has a structure in which a collecting tube 20 having a distal end inserted into the classification tube 1 is provided on the end plate 2 of the classification tube 1. The recovery pipe 20 has the same configuration as that shown in FIG. 1, and is provided to be vertically movable inside the classification tube 1.

In each of the above embodiments, FIGS.
The one shown in FIG. 4 is one in which the recovery pipe 20 is vertically inserted from above the classification cylinder 1, and the one shown in FIG. 4 is one in which it is vertically inserted from below the classification cylinder 1. In each case,
Preferably, the collection tube 20 is inserted vertically, and not at an angle.

This is because, when the collecting pipe 20 is inserted obliquely from above, particles settle inside the collecting pipe 20 and slide back on the inner wall of the collecting pipe 20. As a result, the particles spilled into the classification cylinder 1 from the mouth of the collection pipe 20 sink below the slurry layer and broaden the particle size distribution. In addition, when the collection pipe 20 is inserted obliquely from below, the classification liquid is disturbed along the outer wall of the collection pipe 20, such as sedimentation of particles and rise of supernatant,
This is because the particle size distribution is also widened.

In each of the above embodiments, FIG.
2 and 4, the classification cylinder 1 is entirely filled with the classification liquid. In FIG. 3, the classification liquid is filled up to the outlet of the outflow pipe 4 and the height is used as the liquid level.

In the configuration shown in FIG. 1, since the outflow pipe 4 is not used, there is a possibility that gas will accumulate above the classification cylinder 1 in this configuration. If gas accumulates or does not accumulate depending on the temperature of the day or the like, the amount of the collected liquid changes, and thus the reproducibility of the operation may deteriorate. Therefore, in order to avoid such deterioration of the reproducibility of the operation, it is preferable to provide the outflow pipe 4 as shown in FIGS.

In the case shown in FIG. 4, since the collection pipe 20 is inserted from below the classification cylinder 1, the sealing member 20 is inserted.
It is necessary to devise so that particles do not accumulate on 1.

It is also possible to provide the collection tube 20 on the side wall of the classification tube 1, but in this case, a mechanism for moving the collection tube 20 up and down is required, and the inside of the classification tube 1 is made flat. Therefore, it is necessary to take measures to avoid the sedimentation of the slurry.

The classification liquid is an inorganic or organic liquid, specifically, water, n-pentane, n-hexane, acetone,
It is selected from liquids such as ethyl acetate, methanol, tetrahydrofuran, toluene, silicone oil, and aqueous solution of polyethylene oxide monoether, mainly from the viewpoint of the sedimentation speed when the powder is dispersed and the dispersibility.

From the viewpoint of the sedimentation velocity, a liquid which is low in both density and viscosity and which can quickly sediment the powders is often desired.

In addition, from the viewpoint of dispersibility, it is necessary that the classification liquid sufficiently wets the surface of the powder and granules. In actual selection, consideration must be given to satisfy such requirements, and it is also possible to use a surfactant or the like for improving dispersibility.

In addition, a necessary condition is that the classification liquid does not dissolve the powder or granules or remarkably swell.

Next, more specific shapes, structures, and dimensions of the wet classification device of the present invention will be described with reference to FIGS.

The angle of inclination θ of the end plate 2 is set to be slightly larger than the angle of repose of the granular material in the classification liquid.

That is, since the end plate portion 2 is a portion that slides or rolls after a part of the granular material has settled thereon, its inclination angle θ is larger than the angle of repose of the granular material in the classification liquid. There is a need to. However, when the inclination angle θ is extremely large, the horizontal cross-sectional area becomes relatively small, so that the processing capacity is reduced. In addition, it is conceivable that the height of the apparatus is increased to the extent that the horizontal cross-sectional area is reduced, but in this case, even though the processing amount per batch is the same, the processing time is increased by the height of the apparatus. It will take.

Therefore, it is appropriate to minimize the above-mentioned problems by setting the inclination angle θ of the end plate portion 2 to be slightly larger than the angle of repose of the granular material in the classification liquid.

The height ratio k between the classifying cylinder 1 and the end plate 2 is k.
(= H ₁ / H ₂ ) is preferably about 1.0 to 5.0. If the value of k is larger than this range (k> 5.0),
When the time required for forming a layered structure described later increases, and when the value of k is smaller than this range (k <1.0), the ratio of the amount of particles that can be recovered after the layered structure is once formed to the total number of particles is reduced. In any case, it is not practically preferable.

Here, the charged amount per batch (actual volume)
Where V is the ratio of the charged amount V to the volume W of the classification device, and x is in the range of 5 to 50%, which is the most excellent in classification accuracy and efficiency. If x is smaller than this range (x <5%), the efficiency is remarkably reduced, and if x is larger than this range (x> 50%), troubles such as cake formation may occur.

The volume W of the classifier is

[0045]

[Number 1] W = V / x ≒ (1/8 ) (k + 1/3) (π · tanθ) · D 1 3 is a ... (1), use this formula (1) of the relationship, described above from the various requirements and the necessary charge amount V, it is possible to obtain the design value of the inner diameter D ₁ of the cylindrical portion 1. The dimensions of the other parts, the D ₁
Can be determined based on the value of

In the present embodiment, the outflow pipe 4 has a horizontal end plate 5 connected to the upper end 1b of the classification tube 1, and the center opening 5a of the end plate 5 is used as an outlet 4a.

The inside diameter D _{4 of the} outlet 4 a should not be too large, and is approximately 15% or less of the inside diameter D ₁ of the classification cylinder 1. If it exceeds this, the accuracy will deteriorate. Unless the outlet 4a is clogged, there is little problem due to being too thin.

FIG. 8 is an enlarged view showing a specific shape of the inflow port 3a of the inflow pipe 3. As shown in FIG.

When the inlet 3a has a simple shape, the diameter of the inlet 3a must be very small in order to prevent the backflow of the granular material. However, if the inflow port 3a is too small, there is a problem in that the inflow port 3a is easily blocked by the granular material and the passage of the flow path. Therefore, in order to solve such a problem, in the present embodiment, the bottom 2a of the end plate 2 is used.
The horizontal cross-sectional shape (inner diameter D ₂ ) of the inner wall of the connection portion 3b of the inflow port 3a connected to the
Is formed into a nozzle shape narrower than the horizontal cross-sectional shape (inner diameter D ₃ ) of the inner wall. This makes it possible to prevent backflow in the vicinity of the bottom 2a of the end plate 2.

Here, each inner diameter D ₂ , D ₃ ,
And the values of the nozzle tip width (height) H _3, the following condition (2), (3), is set to a value satisfying the expression (4).

[0051]

## EQU2 ## D_Two≦ 0.05 ・ Φ^1/3・ (Η ・ ρ)^1/9・ (X ・ g ・ ρΔ)^-2/9 ... (2) D_Three≧ 1.2D_Two ... (3) 0 ≦ H_Three≤0.5D_Two (4) where Φ: flux of inflow, η: viscosity of classified liquid, ρ: classified
Density of liquid, x: slurry concentration (volume in wet state
Rate; 0 to 1), g: gravitational acceleration, ρΔ: classification liquid and particles
(Lubricated state). However, these are MSK
Depends on unit. In addition, the expressions (2) to (4), particularly the expression (2)
Coefficient of silica beads of several micrometers
Underwater classification experiment (ρΔ = 1,200kg / m^Three, Device diameter
(Inner diameter) D ₁= 60-240mm)
ing.

It should be noted that the flux Φ of inflow is closely related to the sedimentation velocity of the particles and the order is defined.
The sedimentation rate v, the diameter of the device (inside diameter) and D _1,

[0053]

Φ = (π / 4) · v · D ₁ ² (5) is a condition for balancing.

The sedimentation velocity v is determined on the basis of the infinite dilution sedimentation velocity v ₀ of the particle in question and is complicatedly influenced by other particles. Is approximately expressed by the following equation.

[0055]

V = f · v ₀ (6) v ₀ = (g · ρΔ · d ² ) / (18 · η) (7) Equation (7) is the Stokes sedimentation velocity equation It is. It holds well when the Reynolds number for sedimentation does not exceed 2. In the same range, the concentration factor f is approximated by the following equations.

[0056]

F = ε− ^4.65 (ε ≧ 0.7) (8) f = 6 · (1−ε) / ε ³ (ε ≦ 0.7) (9) ε (= 1-x) is the porosity, and what is effective as the concentration x here is that in the vicinity of the outlet 4a of the upper end 1b of the classification cylinder 1 during operation. This is a value somewhat smaller than the charged concentration.

The simplest configuration of the mixing section 10 is based on a simple horizontal stirring blade. As a stirring blade in this case, a rod-shaped blade having a low stirring force and causing only the horizontal movement of the classification liquid is suitable.

FIG. 7 shows an example of a more preferable structure of the mixing section 10. That is, the whole is cylindrical, the inlet 11 is formed at the lower end, and the outlet 12 is formed at the upper end.
Is formed, and the stirring blade 13 is housed therein.

The inlet 11 of the mixing section 10 is located above the inlet 3a. The outlet 12 of the mixing section 10
Is most preferably provided at substantially the same height as the seam 1a between the classification tube 1 and the end plate portion 2.

As such a cylindrical mixing section 10,
Specifically, there are a case where the stirring blade 13 is forcibly driven by power and a case where a static mixer is used.
FIG. 7 illustrates the case of a static mixer.

In the case of a static mixer, an upflow can be obtained without the need for active power, for example, on the same principle as that of a strong upflow in a chimney. In this case, in particular, the length of the mixing section 10 is preferably long as long as the inflow port 11 on the lower end side is not too close to the bottom 2a of the end plate section 2 and does not block the flow of the classification liquid. Is good. In addition, the shape and dimensions of the element become coarse,
It is not preferable that the number of repetitions is too small. Further, an umbrella 19 may be provided at the lower end of the mixing unit 10 to ensure that the upward flow passes through the static mixer.

The dimensional requirements of the static mixer are as follows from Bernoulli's theorem.

[0063]

[6] _{(π / 4) · D 6} 2 = k · (1 + N E · α E) · Φ / 2 · H 4 · x · ρΔ / ρ) 1/2 ··· (10) However, k ≧ 2 (desirably k ≧ 5), N _E : number of elements, α _E : pressure loss coefficient per element, Φ: minimum value of inflow of classified liquid.

As a static mixer, the entire surface is smoothly finished so that the particles do not accumulate due to sedimentation, and the internal inclination angles are all larger than the repose angle of the particles. It is desirable that

Next, a description will be given of a classification method using the wet classification apparatus having the above-described configurations.

That is, if the classification liquid is kept flowing from the inflow pipe 3 at a constant flow rate which is not too high after the powder to be classified is charged into the apparatus as a slurry, a gentle layered structure is formed in the classification cylinder 1. The layered structure here means
Larger diameter particles mean lower, higher volume fractions and smaller particles have higher, lower volume fractions in an orderly arrangement.

When such a layered structure is completed, the collection tube 20 is moved upward to collect particles in order from the upper layer of the completed layered structure.

When the slurry is continuously recovered through the recovery pipe 20, all components having a particle size smaller than a certain threshold (this is referred to as a first threshold) existing above the tip of the recovery pipe 20 are absorbed. Will be issued.

Thereafter, when the collection pipe 20 is slightly lowered to perform collection, a portion of the slurry remaining in the classification cylinder 1 corresponding to a new position (height) at the tip of the collection pipe 20 is obtained. A component having a smaller particle size than the value (this is referred to as a second threshold), that is, a component between the first threshold and the second threshold is extracted.

In this way, the recovery is performed while the recovery pipe 20 is gradually lowered, and the components whose particle diameter gradually increases with a constant threshold value width are successively sucked out.

It should be noted that, if the width of one drop of the collecting pipe 20 is reduced, particles having a narrower particle size range can be collected.

Next, the following experiment was conducted using the wet classification apparatus and the wet classification method of the present invention. [Embodiment] In accordance with FIGS.
₁ = 480 mm, D ₂ = 1.5 mm, D ₃ = 3 mm, D
_{4 = 6mm, H 1 = 320mm} , H 2 = 480mm, H
₃ = 0.5 mm, H ₄ = 260 mm, θ = 53 °, and the volume was 106.2 liters. The supply of the classification liquid was performed by a metering pump, and the number of elements of the static mixer used as the mixing unit 10 was 22. Also,
The collection tube 20 has an inner diameter of 4 mm and an outer diameter of 6 mm.
It was inserted vertically from above through a seal member made of fluorinated ethylene.

At room temperature, water (η = 1.0 × 1)
0 ^-3 Pas · sec, ρ = 1000 kg / m ³ ), and ρ = 1130 kg / m ³ (ρΔ = 130 kg /
m ³ ) of the thermosetting resin beads were classified. The particle size is d =
An average value of 9.9 μm, d = 8.2 μm to d = 1
A substantially normal distribution having a weight of 90% within 2.1 μm was used. The charged amount is apparently 19.3 liters (for the volume below the classifying cylinder 1 with the outlet pipe 4 of the classifying cylinder 1 attached,
25%), and the actual volume was 13.5 liters.

The flow rate condition was 30 ml / min consistently, but first, the formation of the layered structure was waited for 14 days. During this time, the tip of the collection pipe 20 is positioned 10 mm from the upper end of the inner wall of the classification cylinder 1.
mm.

Next, the tip of the collection tube 20 was lowered to a position 160 mm from the upper end of the inner wall of the classification tube 1 and left for 15 hours. Subsequently, the operation of lowering this by 10 mm and waiting for one hour was repeated. The effluent slurry (1.2 liters each) for this hourly period was taken as one fraction, and a sample of 24 fractions was obtained in 48 hours. Although the sample was in the form of slurry, it was left in the container (reagent bottle) for one day and night to obtain a cake which was collected in the bottom of the container. The total amount (apparent volume) of the cake was 9.1 liters. The range of the average particle size of each sample is from 8.3 μm to 9.9 μm, and a good CV value (coefficient of variation) indicating the distribution width of each fraction is from 2.3% to 2.8%. Value. However, the definition of the CV value is

[0076]

[Mathematical formula-see original document] CV value = standard deviation of particle size / average value of particle size.

[0077]

The wet classification apparatus according to the first aspect of the present invention is a wet classification apparatus utilizing sedimentation caused by gravity, and is provided at an upright cylindrical classification cylinder and at a lower end of the classification cylinder. It is configured to include an inflow means for inflowing the classification liquid, and a particle collection pipe whose tip is inserted into the classification cylinder and which is vertically movable inside the classification cylinder. Further, in the wet classification method according to the second aspect of the present invention, the classification liquid flowing from the inflow means is maintained at a substantially constant flow rate to create an ascending flow at the same speed as the sedimentation velocity of the powder and granules, and is formed inside the classification cylinder. After forming a layered structure according to the particle size, the collection tube is sequentially moved from the upper position to the lower position while keeping the flow rate of the classification liquid substantially constant, so that the particles in the upper layer of the layered structure are sequentially collected through the collection tube. I do. In this way, despite the simple structure in which the collection tube is inserted vertically into the classification tube so that it can be moved up and down, there is no need to separate particles from a large amount of dilute slurry flowing out of the outflow tube. Since the slurry can be collected as a concentrated slurry, the collection operation can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a wet classification device of the present invention.

FIG. 2 is a schematic configuration diagram showing one embodiment of a wet classification device of the present invention.

FIG. 3 is a schematic configuration diagram showing one embodiment of a wet classification device of the present invention.

FIG. 4 is a schematic configuration diagram showing one embodiment of a wet classification device of the present invention.

FIG. 5 is a diagram showing a basic configuration of a wet classification device of the present invention.

FIG. 6 is a schematic configuration diagram of a wet classification device of the present invention, which is displayed in a dimension.

FIG. 7 is a partially enlarged sectional view showing a structure of a mixing section.

FIG. 8 is a partially enlarged sectional view showing a specific shape of an inflow port of the wet classification device of the present invention.

FIG. 9 is a schematic configuration diagram showing a basic form of a classifier using a rising flow and a batch operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Classification cylinder 2 End plate part 3 Inflow pipe 3a Inflow port 4 Outflow pipe 4a Outflow port 10 Mixing part 20 Recovery pipe

Claims (2)

[Claims] 1. A wet classifier utilizing sedimentation caused by gravity, comprising: an upright cylindrical classifier, an inflow means provided at a lower end of the classifier for flowing a classifying liquid, and a tip portion comprising: A wet classification device, comprising: a particle collection tube inserted into a classification cylinder and vertically movable inside the classification cylinder. 2. An upright cylindrical classifying cylinder, an inflow means provided at a lower end of the classifying tube for flowing a classifying liquid, and a tip inserted into the classifying tube. In a wet classifier utilizing sedimentation by gravity, provided with a collection pipe for particles vertically movably provided therein, the sedimentation of powder and granules is maintained by maintaining the classifying liquid flowing from the inflow means at a substantially constant flow rate. After forming an upward flow at the same speed as the velocity and forming a layered structure according to the particle diameter inside the classification cylinder, the collection tube is sequentially moved from the upper position to the lower position while keeping the flow rate of the classification liquid substantially constant. The wet classification method comprises sequentially collecting particles in the upper layer of the layered structure through a collection tube.