JPH0423586B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a microparticle classification device for classifying microparticles such as powder or pulverized materials by a wet method.

[Conventional technology]

Conventionally, as a device for classifying microparticles such as polymerized beads and other plastic spheres and ceramic raw material powder, there are two types of devices: one that directly classifies microparticles based on their size itself, and the other that uses microparticles based on their weight, resistance to water, air, etc. There are devices that indirectly classify particles using their kinetic energy, etc.

Examples of the latter include, for example, static classifiers, hydraulic classifiers, mechanical classifiers, centrifugal classifiers, and the like.

Static classifiers apply the area law to classify by static gravity sedimentation and overflow, but this type of classifier has low classification accuracy, especially when the frequency of supply of the material to be classified changes. It has the disadvantage that the classification point is easily variable.

Hydraulic classifiers use the interference of vertical or diagonally upward water flow to cause fine particles to overflow and coarse particles to settle.The classification point tends to change due to fluctuations in the water flow, and if turbulence occurs, the classification It has the disadvantage that it may become impossible.

A mechanical classifier is a classification device that has a configuration in which coarse grain products are thrown out using mechanical force, and the classification accuracy is low.
It can only be used for rough classification.

Furthermore, although centrifugal classifiers use centrifugal force to strengthen the separation force of classification, they have the disadvantage that accuracy deteriorates due to turbulence generated during rotation.

In this way, classification devices that classify microparticles using their physical properties such as specific gravity and weight tend to cause fluctuations in classification points and decreases in classification accuracy due to fluctuations in various factors. It cannot be applied to classification, which is often used in fields that are considered cutting-edge technology.

On the other hand, as a device for classifying microparticles based on their size, a so-called classification device using a sieve is used.

By the way, as the size of microparticles decreases, aggregation and coalescence occur due to the influence of surface charges, etc., which reduces classification accuracy and causes clogging, which reduces classification efficiency. do. Therefore, many of the classification apparatuses using the above-mentioned sieves are wet-type ones in which microparticles are dispersed in a dispersion liquid as a medium and then sieved.

In other words, the surface charge of the fine particles is neutralized in the dispersion liquid, and the dispersibility thereof is enhanced. Furthermore, if a surfactant is used in combination, the dispersibility can be further improved. Therefore, it is possible to prevent agglomeration and coalescence of microparticles, reduce clogging of the sieve, and make it easier for the microparticles to pass through the sieve openings.

[Problem that the invention seeks to solve]

However, in the conventional microparticle classification apparatus described above, as the size of the microparticles decreases, the pore size of the sieve becomes finer, so even if the microparticles are dispersed in the dispersion liquid, clogging tends to occur. In particular, when the classified material is caused to flow from above to below the sieve, clogging is more likely to occur, resulting in a problem in that the classification efficiency and accuracy are reduced.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve classification accuracy and classification efficiency by preventing clogging of the sieve, and furthermore, to provide an easy-to-assemble device for classifying microparticles. Our goal is to provide the following.

[Means for solving problems]

In order to achieve the above object, the device for classifying microparticles according to the present invention is provided with a sieve that obstructs the cross section of the classification tank at an angle, and a sieve that closes the cross section of the classification tank at a lower side than the sieve. on the wall of
An inlet for introducing a dispersion liquid in which fine particles are dispersed is provided, and a collection port for collecting the dispersion liquid and fine particles that have passed through the sieve is provided on the upper wall near the inclined lower end of the sieve in the classification tank. Further, the present invention is characterized in that an ultrasonic vibration generating means is provided on the bottom side of the classification tank for transmitting ultrasonic waves into the dispersion liquid in the classification tank to vibrate the sieve.

[Effect]

With the above configuration, the classified material flows from the bottom to the top of the sieve, so that the sieve is less likely to become clogged. Furthermore, the ultrasonic waves sent out from the ultrasonic vibration generation means provided at the bottom of the classification tank propagate through the dispersion liquid in the classification tank and vibrate the sieve, thereby preventing microparticles from adhering to the sieve. Since this is suppressed, clogging of the sieve can be more reliably prevented. As a result, classification accuracy and classification efficiency are improved. In addition, in order for the sieve to vibrate in resonance with the ultrasonic waves sent out from the ultrasonic vibration generating means as described above, the sieve must be placed at a position that matches the wavelength of the ultrasonic waves sent out from the ultrasonic vibration generating means. However, in the above configuration, since the sieve is arranged at an angle,
Even if the position of the sieve in the height direction changes somewhat, any position of the sieve will match the resonance point with the ultrasonic waves sent out from the ultrasonic vibration generating means, and this will cause the sieve to The entire vibration state can be obtained. Therefore, it is not necessary to precisely adjust the position of the sieve relative to the ultrasonic vibration generating means, and assembly can be easily performed.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

As shown in FIGS. 1 to 5, a discharge tank 13 is provided through a sieve 12 at the upper part of the introduction tank 11 into which the dispersion liquid in which fine particles are dispersed is introduced, and a classification tank is configured. There is. The sieve 12 used has a mesh opening of about 50 μm, for example, and is inclined so that the height from the lower end to the upper end is about 3 cm to 20 cm.

Further, an introduction port 14 is provided on the side wall near the lower part of the introduction tank 11, through which a dispersion liquid and microparticles dispersed by the dispersion liquid are introduced from a liquid feeding pump (not shown). An ultrasonic vibration generating means 15 is provided at the bottom of the introduction tank 11 and is connected to an oscillator 16 provided outside the introduction tank 11 .

As shown in FIGS. 6 and 7, the introduction tank 11 and the discharge tank 13 have a flange part 11a provided at the upper end of the introduction tank 11 and a flange part 13a provided at the lower end of the discharge tank 13. 17... and nuts 18... are fastened and joined.

The end of the sieve 12 is located between the concave portion 11b formed in the flange portion 11a provided at the upper end of the introduction tank 11 and the convex portion 13b formed in the flange portion 13a provided at the lower end of the discharge tank 13. 12a is sandwiched. Further, an O-ring 19 is fitted between the flange portion 11a and the flange portion 13a outside the concave portion 11b and the convex portion 13b to prevent the dispersion from leaking.

On the other hand, near the lower end of the sieve 12 in the discharge tank 13, a collection port 21 for collecting the dispersion liquid and microparticles that have passed through the sieve 12 is provided so that there is no step between the collection port 21 and the sieve 12.

In the above configuration, the fine particles dispersed in the dispersion liquid are introduced into the introduction tank 11 from the introduction port 14 by the liquid feeding pump. When the liquid level of the dispersion liquid inside the introduction tank 11 rises and exceeds the lower end of the sieve 12, part of the microparticles and the dispersion liquid pass through the sieve 12 and begin to flow out from the collection port 21.

However, if the opening of the sieve 12 is about 50 μm or less, the pressure loss when the dispersion liquid passes through the sieve 12 becomes large. Therefore, the pressure inside the introduction tank 11 is maintained, and the liquid level of the dispersion inside the introduction tank 11 further rises. Eventually, when the liquid level of the dispersion liquid reaches near the upper end of the sieve 12, the dispersion liquid passes through the sieve 12.
It gradually passes through the sieve 12 from almost the entire area. Sieve 12
The dispersion liquid that has passed through forms a liquid flow toward the lower end of the sieve 12 and flows out from the sampling port 21.

At this time, the microparticles that have passed through the sieve 12 together with the dispersion liquid are swept away by the flow of the dispersion liquid and quickly reach the sampling port 21 . Therefore, once sieve 1
The proportion of microparticles that have passed through the sieve 2 returning to the lower side of the sieve 12 is extremely low. Moreover,
As mentioned above, the liquid flow from the upper end of the sieve 12 to the sampling port 21 is reliably formed by the weight of the dispersion because the sieve 12 is provided at an angle.
There is no need to use a special pump or the like.

Further, since the dispersion liquid and the microparticles flow upward from the bottom of the sieve 12, the sieve 12 is less likely to become clogged. Furthermore, if the sieve 12 provided with the ultrasonic vibration generating means 15 generates fine vibrations, clogging of the sieve 12 is further prevented, so that the classification efficiency can be increased.

By the way, when the ultrasonic vibration generating means 15 is provided in the introduction tank 11 as described above, the strength of the vibration generated in the sieve 12 differs depending on the height at which the sieve 12 is provided. Therefore, the sieve 12
It is desirable to install the sieve 12 at a height where the vibration is strongest, but the height where the vibration of the sieve 12 is strongest is
For example, the position may vary slightly due to variations in the dimensions and materials of each part in the introduction tank 11, and the position will not be constant for each device.

Therefore, for example, by providing the sieve 12 at an angle so that the height from the lower end to the upper end is about 3 cm to 20 cm, at least some part of the sieve 12 is subjected to strong vibrations. Therefore, since the entire sieve 12 is always strongly vibrated, the ultrasonic vibration generating means 15 can effectively prevent clogging of the sieve 12.

As described above, in the above embodiment, the classified material flows from the bottom to the top of the sieve, so that the sieve is less likely to become clogged. Further, since the sieve is provided at an angle, the area of the sieve can be increased compared to a case where the sieve is provided horizontally in a classification tank of the same size, and the classification efficiency is increased. Moreover, the dispersion that has passed through the sieve quickly flows toward the collection port, and the microparticles that have passed through the sieve are swept away together with the dispersion into the collection port, so that once they have passed through the sieve, they return to the bottom side of the sieve. The proportion of small particles that are trapped is reduced. Therefore, the precision and efficiency of classifying microparticles can be significantly improved.

Furthermore, since the sieve 12 is provided at an angle, any part of the sieve 12 resonates with the ultrasonic waves sent out from the ultrasonic vibration generating means 15 and is strongly vibrated. Therefore, since the entire sieve 12 is always strongly vibrated, there is no need to make strict adjustments to the mounting position of the sieve 12 to prevent clogging of the sieve 12 by the ultrasonic vibration generating means 15.
Assembly work can be performed easily.

〔Effect of the invention〕

As described above, in the microparticle classification device according to the present invention, the sieve that closes the cross section of the classification tank is installed at an angle inside the classification tank, and on the wall surface below the sieve in the classification tank, An inlet for introducing a dispersion liquid in which fine particles are dispersed is provided, and a collection port for collecting the dispersion liquid and fine particles that have passed through the sieve is provided on the upper wall near the inclined lower end of the sieve in the classification tank. Further, the configuration is such that an ultrasonic vibration generating means is provided on the bottom side of the classification tank for transmitting ultrasonic waves into the dispersion liquid in the classification tank to vibrate the sieve.

As a result, the classified material flows from the bottom to the top of the sieve, making it difficult for the sieve to become clogged. Furthermore, the ultrasonic waves sent from the ultrasonic vibration generating means provided at the bottom of the classification tank propagate through the dispersion liquid in the classification tank and vibrate the sieve, thereby
Since the adhesion of microparticles to the sieve is suppressed, clogging of the sieve can be more reliably prevented. As a result, classification accuracy and classification efficiency are improved. In addition, in the above, since the sieve is arranged at an angle, even if the position of the sieve in the height direction changes somewhat, any position of the sieve will be sent out from the ultrasonic vibration generating means. This coincides with the resonance point with the ultrasonic waves, and thereby the vibration state of the entire sieve can be obtained. Therefore, it is not necessary to precisely adjust the position of the sieve relative to the ultrasonic vibration generating means, and as a result, the assembly can be easily performed.

[Brief explanation of drawings]

Figures 1 to 7 show an embodiment of the present invention, in which Figure 1 is a cross-sectional front view showing the configuration of the classification device, Figure 2 is a plan view thereof, and Figure 3 is a bottom view of the same. , Figure 4 is a left side view of the same, Figure 5 is a right side view of the same,
FIG. 6 is an enlarged sectional view showing the state of assembly at the joint between the introduction tank and the discharge tank, and FIG. 7 is an enlarged sectional view showing the assembled state of the joint. 11 is an introduction tank (classification tank), 12 is a sieve, 13 is a discharge tank (classification tank), 14 is an introduction port, 15 is an ultrasonic vibration generating means, and 21 is a sampling port.

Claims (1)

[Scope of Claims] 1. A sieve that closes the cross section of the classification tank is installed at an angle inside the classification tank, and a dispersion liquid in which microparticles are dispersed is disposed on the wall surface of the classification tank below the sieve. While an introduction port is provided for introduction,
A collection port for collecting the dispersion liquid and microparticles that have passed through the sieve is provided on the upper wall near the lower end of the sieve in the classification tank, and on the bottom side of the classification tank,
A device for classifying microparticles, comprising an ultrasonic vibration generating means for transmitting ultrasonic waves into a dispersion liquid in a classification tank to vibrate the sieve. 2 The height of the above sieve from the bottom edge to the top edge is 3cm.
2. The device for classifying microparticles according to claim 1, which is installed at an angle of about 20 cm to 20 cm.