JP2002035698A - Wind sieve device and sieve net structure - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a wind sieving apparatus capable of reducing clogging of a sieve net as much as possible and simultaneously improving classification efficiency and classification accuracy. SOLUTION: A raw material powder supply chamber 20 and a sieved powder collection chamber 30 are communicated through a sieve mesh 60, and a reinforcing member 70 of the sieve mesh 60 is disposed on the collection chamber side of the sieve mesh 60. Air nozzle 36 that blows backwash air to prevent clogging of sieve screen 60
When the sieve net 60 is bent by the backwash air, the sieve net 60
The clogging prevention member 50 is provided at a position where the contact is made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind sieving apparatus capable of preventing clogging of a sieve mesh and improving classification efficiency and classification accuracy.

[0002]

2. Description of the Related Art Powder materials are used in accordance with their uses and purposes.
As a device for sieving to a desired particle size distribution, there is a sieving device using wind power. As shown in FIG. 10, the wind sieve device (10) has a sieve net (60) arranged between a raw material powder supply chamber (20) and a sieved powder recovery chamber (30). Yes, form an air flow from the supply chamber (20) to the collection chamber (30) through the sieve mesh (60), and spray the raw material powder on the sieve mesh (60) with the air flow,
This is a device for separating and recovering powder that has passed through the sieve screen (60) and powder that has not passed. Since large-diameter powder that cannot pass through the sieve mesh (60) adheres to the sieve mesh (60) and causes clogging, backwashing is performed by blowing high-pressure air onto the sieve mesh (60) from the collection chamber side. Prevents clogging.

When sieving fine powder having a classification point of about 20 μm or less, it is currently difficult to prepare a sieve net having a small opening (less than 16 μm) using a metal material such as stainless steel. In many cases, a sieve net is made from a resin such as nylon or polyester and used. A sieve mesh with a small opening is also made thinner. Therefore, when the sieve mesh (60) is exposed to the airflow from the supply chamber (20) to the collection chamber (30), the sieve net (60) is bent toward the collection chamber. If the amount of bending is large, the sieve mesh (60) is elongated and the mesh size is increased, so that even a powder having a size larger than desired passes through the mesh, causing a problem that the classification accuracy is reduced.

[0004] Therefore, in the recovery chamber side of the sieve screen (60), FIG.
As shown in FIG. 11 and close to the sieve screen (60),
A wire mesh with a larger opening than (0) is arranged as a reinforcing member (70), and the sieve mesh (60) is in contact with the reinforcing member (70) even if the sieve mesh (60) is bent to the collection chamber side by the air flow. Then, the openings are prevented from becoming larger by bending further.

[0005]

The wind sieving apparatus (10) includes:
Improvements in classification efficiency and classification accuracy are required. In order to achieve these improvements, it is an issue how to reduce the clogging of the sieve screen (60). As described above, clogging was conventionally reduced by backwashing, but clogging could not be sufficiently prevented only by backwashing. Because the powder that falls off from the sieve mesh by the backwash air is a part of the adhering powder, most of the powder only floats slightly from the sieve mesh and then adheres to the sieve mesh again by the air flow. It is.

An object of the present invention is to provide a wind sieving apparatus which can reduce clogging of a sieve mesh as much as possible and can simultaneously improve classification efficiency and classification accuracy.

[0007]

In order to solve the above-mentioned problems, a wind sieving apparatus (10) of the present invention comprises a raw material powder supply chamber (20).
And the collection chamber (30) for the sieved powder are communicated through a sieve mesh (60), and a reinforcing member (70) of the sieve mesh (60) is arranged on the collection chamber side of the sieve mesh (60). In a wind sieve device equipped with an air nozzle (36) for blowing backwash air to prevent clogging of the sieve net (60), a sieve net (60) A clogging prevention member (50) was provided at a position where the sieve mesh (60) was in contact when the was bent by the backwash air.

[0008]

[Operation and Effect] When sieving is started, powder that does not pass through the sieving surface adheres to the sieving net (60) and is clogged. However, when the backwash air is blown onto the sieve screen (60), some of the attached powder drops off from the screen (60), and the remaining powder is slightly removed from the screen (60). Float. At this time, the sieve mesh (60) is bent toward the supply chamber side by the backwash air, so that the sieve mesh was in contact with the clogging prevention member (50) and was attached to the surface of the sieve mesh (60) by the impact. The powder is beaten off and falls off the sieve screen (60). In the area where the backwash air is not blown, the sieve mesh (60) is bent toward the collection chamber by the airflow from the supply chamber (20) to the collection chamber (30) and comes into contact with the reinforcing member. The powder on the surface of the screen is beaten off and falls off the screen. As described above, during sieving, the sieve mesh contacts both members while swaying between the clogging prevention member and the reinforcing member, and vibrates and knocks off the contact, so that the sieve mesh is removed. Since the powder causing the clogging does not fall off and remains, the clogging is eliminated, and the classification efficiency and the classification accuracy of the wind sieving apparatus are both improved.
The screen structure used in the wind screen device (10) of the present invention is a screen screen.
Since the clogging prevention member (50) is arranged on the supply chamber side of (60) and the reinforcing member (70) is arranged on the collection chamber side, it can be attached to the conventional wind sieve device, and clogging of the sieve mesh To prevent
Improvement in classification efficiency and classification accuracy can be achieved.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A wind sieving apparatus (10) is provided in a classifier (40) formed between a raw material powder supply chamber (20) and a sieved powder recovery chamber (30). The clogging prevention member (50), the sieve mesh (60), and the reinforcing member (70) are arranged in order from the supply chamber side.

The supply chamber (20) has an input port (22) for raw material powder,
Discharge ports (24) for coarse powder that could not pass through the sieve mesh are provided at the top and bottom, respectively, and communicate with the classification path (40) between the input port (22) and the discharge port (24). . An air inlet (26) is formed at a position facing the classifying path (40). The air inlet (26) is an air feeder (not shown) such as a fan on the upstream side.
The air flow is sent out from the air inlet (26) toward the classification path (40), and the raw material powder supplied from the input port (22) is blown to the classification path (40) by the air flow.

The classifying passage (40) is a passage having a circular cross section,
As shown in FIGS. 1 and 2, a clogging prevention member (50), a sieve net (60), and a reinforcing member (70) are fitted in order from the upstream side (supply chamber side).

The sieve net (60) is a net having openings corresponding to the particle size to be sieved, and can be fixed to a circular frame (not shown) or the like on the inner surface of the classifier (40). it can. If the sieve mesh has a mesh size of more than about 16 μm, it can be made of a metal material such as stainless steel in addition to a polymer resin such as nylon or polyester. Aperture is about 16μ
It is currently difficult to produce a sieve mesh of m or less from a metal material, and is made of a resin such as nylon or polyester.
As will be described later, the sieve net (60) needs to be vibrated to bend in response to the backwash air and to be brought into contact with the clogging prevention member (50) to shake off the attached powder. Therefore, the sieve mesh (6
In the case of (0), it is not preferable that the tension is too tight, and it is desirable that the tension is slightly weakened with some margin.

On the upstream side of the sieve net (60), a clogging prevention member (5
0) is deployed. The clogging prevention member (50) can be formed of a wire mesh or a grid (including a horizontal grid, a vertical grid, or the like) having openings that are several times to several tens times or more larger than the particle diameter of the raw material powder.
The clogging prevention member (50) is also fixed to a circular frame or the like in the same manner as the sieve net, and is installed on the inner surface of the classification path (40). Clogging prevention member
(50), as shown in FIGS. 1 and 3, when the sieve mesh (60) is bent by receiving backwash air, the sieve mesh (60) is a member for preventing clogging.
It is arranged close to the sieve screen (60) so that the powder adhering to the surface of the sieve screen (60) in contact with the (50) is shaken off. Sieve mesh (6
The distance between (0) and the clogging prevention member (50) is preferably about 0.2 to 2 mm, more preferably about 0.5 to 1 mm.

A reinforcing member (70) is provided downstream of the sieve screen (60). Like the clogging prevention member (50), the reinforcing member (70) is also formed of a wire mesh or grid having openings that are several times to several tens times or more larger than the particle diameter of the raw material powder, and is fixed to a circular frame or the like. Then, it is deployed on the inner surface of the classifier (40).

The collection chamber (30) has a collection port (32) for collecting powder sieved through the sieve net (60), and a discharge port for discharging the air flow supplied from the supply chamber (20). An air port (34) is formed. In FIG. 1, in order to separate the sieved powder and exhaust air by gravity, a powder recovery port (32) is provided in a recovery chamber.
It is provided below (30). The collection room (30) further contains a sieve screen (6
An air nozzle (36) for blowing backwash air toward 0) is provided. The air nozzle (36) is a substantially L-shaped pipe having a rotation center on an extension of the center of the classifying path (40), and having a tip bent in the radial direction of the classifying path (40). The base end of the pipe is connected to driving means such as a motor, and the air nozzle rotates at a predetermined cycle. A slit is formed in the bent portion of the pipe toward the classification path (40), and air sent from the base end of the pipe is blown from the slit to the sieve net (60) as backwash air.

In the wind sieve device (10) having the above structure, an air flow is fed from the air inlet (26) to the classification path (40), and the backwash air is supplied while rotating the air nozzle (36). . The sieve net (60) is bent toward the collection chamber by the air flow,
The part that comes into contact with the reinforcing member (70), but is blown by the backwash air, is bent to the supply chamber side, and the clogging prevention member
Contact with (50). By rotating the air nozzle (36), the sieve mesh (60) becomes a reinforcing member (70) and a clogging prevention member (50).
Vibrates while contacting both.

When the raw material powder is charged from the charging port (22),
The raw material powder is sprayed toward the classifying path by the airflow while falling downward from the inlet (22).

The raw material powder that has entered the classification path (40) passes through a clogging prevention member (50) having a large opening, and is sieved with a sieve screen (60). The powder having a smaller particle size than the mesh of the sieve mesh (60) is pushed by the air flow, passes through the mesh of the sieve, and is collected in the collecting chamber (3).
0), but the powder having a particle size larger than the mesh of the sieve mesh (60) cannot pass through the mesh of the sieve mesh (60), and adheres to the surface of the sieve mesh (60) to prevent clogging. Wake up.

As described above, the air nozzle (36) blows backwash air onto the sieve net (60) while rotating at a predetermined cycle. The backwash air blown to the sieve screen (60)
A part of the powder adhering to 0) is lifted up and dropped off, and the sieve mesh (60) is bent toward the supply chamber as shown in FIGS. 3 (a) and 3 (b). Since the sieve mesh bent toward the supply chamber comes into contact with the clogging prevention member (50) disposed close to the powder, the powder attached to the surface of the sieve mesh is shaken off by the clogging prevention member (50). .

After the air nozzle (36) has passed,
The sieve net (60) is bent toward the collection chamber by the air flow and comes into contact with the reinforcing member (70), and the attached powder is shaken off by the impact.

By vibrating the sieve mesh (60) while contacting the clogging prevention member (50) and the reinforcing member (70), powder causing the clogging is removed from the surface of the sieve mesh. The clogging is eliminated and the sieving capacity of the screen is restored.

The sieve mesh (60) is not limited to a single sieve as shown in FIG. 2, but a plurality of sieves can be used as shown in FIG. 4 to improve the classification accuracy. . In addition,
In this case, the interval between the sieve screens, when the sieve screens (60), (62), (64) are bent by the backwash air, is set to an interval at which the sieve screens (60), (62), (64) can contact each other. It is desirable. In the case of the conventional wind sieve device, when the sieve nets are used in layers (especially three or more), the backwash air does not sufficiently reach all the sieve nets, resulting in immediate clogging. However, in the case of the present invention, even when the sieve screens (60), (62), and (64) are used in layers, when the backwash air is blown, the upstream screen screen (60) is not clogged with the clogging prevention member ( 50), the adhering powder falls off, and the remaining sieves (62) and (64) are respectively the upstream sieves (60).
Since the powder comes off upon contact with (62), clogging of any sieve mesh is eliminated.

When a plurality of sieve nets (60) and (62) are used, as shown in FIG. 5, not only one clogging prevention member (50) and (52) is installed on the upstream side, but also It is desirable to insert each between adjacent sieve nets. Each sieve net (60) (62) is in contact with the clogging prevention members (50) (52), compared with the case where the sieve nets are in contact with each other, the falling off of the attached powder,
This is because it can be performed more effectively.

[0024]

EXAMPLE A wind sieving apparatus was prepared in which the presence / absence of a clogging prevention member and the number of sieve nets were changed, and the classification efficiency and the classification accuracy were measured.
In the measurement, Invention Example 1 (FIG. 2) in which a clogging prevention member (50), a sieve net (60), and a reinforcing member (70) were arranged one by one between the supply chamber and the recovery chamber in order from the upstream side. Reference), clogging prevention member (50)
Inventive Example 2 (see FIG. 4) in which three screens (60), (62), and (64) are arranged between the reinforcing member (70) and the screen (60) without the clogging prevention member. ) And a reinforcing member (70) were used, and a wind sieve device of a comparative example (see FIG. 11) was used.

The specifications of each wind sieve device are as follows.・ Clogging prevention member: stainless steel, diameter 150mm, aperture 0.5mm, thickness 0.5mm ・ Sieve mesh: nylon, diameter 150mm, aperture 20μm,
0.055mm thickness ・ Reinforcing member: stainless steel, diameter 150mm, aperture 0.5mm, thickness 0.5mm ・ Backwash air: 0.2MPa, rotation cycle 150rpm

With respect to Inventive Example 1, Inventive Example 2, and Comparative Example, Ni-Si powder was charged as raw material powder and sieved. The results are shown in Table 1 and FIG. Also,
Micrographs of the classified fine powder are shown in FIGS. 7 to 9. The classification efficiency was evaluated by dividing the weight of the fine powder after classification by the total weight of the fine powder in the raw material powder and multiplying by 100. The particle size distribution of each powder was measured using a laser diffraction / scattering type particle size distribution analyzer (manufactured by Horiba, Ltd.). The classification accuracy is as follows:
It was evaluated by measuring the relative volume ψ (%) of the powder exceeding 0 μm. Therefore, the smaller ψ is, the higher the classification accuracy is.

[0027]

[Table 1]

Referring to Table 1 and FIG. 6, it can be seen that Inventive Example 1 and Inventive Example 2 have higher classification efficiency than the Comparative Example. Further, the relative volume of the powder having a particle size of more than 20 μmm
Is smaller than that of the comparative example, and the classification accuracy is excellent. The invention examples are superior to the comparative examples because the clogging of the sieve mesh is reduced by the provision of the clogging prevention member, and the sieving ability and the classification accuracy of the sieve mesh are improved.

Comparing Inventive Example 1 with Inventive Example 2, the classification efficiency is slightly improved in Inventive Example 2, and the classification accuracy is significantly improved in Inventive Example 2 using three screens. It can be seen that it has improved. Therefore, Comprehensive evaluation of Inventive Example 1, Inventive Example 2, and Comparative Example shows that Inventive Example 2 is the best, followed by Inventive Example 1.

FIG. 7 is a micrograph of the classified fine powder.
Referring to FIG. 9 to FIG. 9, it can be seen that in Invention Example 2 (FIG. 8), almost no coarse powder is mixed, and the powder is fine as a whole. In addition, in Invention Example 1 (FIG. 7), the powder is fine as a whole, though there is some mixing of coarse powder. On the other hand, in the comparative example (FIG. 9), it can be seen that the classification was inferior in accuracy due to the large amount of coarse powder mixed.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a wind screen device of the present invention.

FIG. 2 is a perspective view showing a clogging prevention member, a sieve net, and a reinforcing member.

FIGS. 3A and 3B are explanatory views showing a phenomenon in which a sieve mesh is bent between a clogging prevention member and a reinforcing member.

FIG. 4 is a perspective view showing a different embodiment of the present invention.

FIG. 5 is a perspective view showing still another embodiment of the present invention.

FIG. 6 is a particle size distribution graph showing a classification result of an example.

FIG. 7 is a drawing substitute photograph of the fine powder of Inventive Example 1 taken with a microscope.

FIG. 8 is a drawing substitute photograph of the fine powder of Invention Example 2 taken with a microscope.

FIG. 9 is a drawing-substituting photograph taken of a fine powder of a comparative example using a microscope.

FIG. 10 is an explanatory diagram of a conventional wind screen device.

FIG. 11 is a perspective view showing a sieve net and a reinforcing member of a conventional wind sieve device.

[Explanation of symbols]

 (10) Wind screen device (20) Supply room (30) Recovery room (36) Air nozzle (40) Classification path (50) Anti-clogging member (60) Sieve net (70) Reinforcing member

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masao Sakurai 1-1-1 Hama, Amagasaki-shi, Hyogo F-term in Kubota Technology Development Laboratory Co., Ltd. (Reference) 4D021 FA02 FA18 GA02 GA06 GA08 GA12 GA13 GA14 GA25 GA29 GB01 HA10

Claims (5)

[Claims] 1. A raw material powder supply chamber (20) and a sieved powder collection chamber (30) are communicated through a sieve mesh (60), and are connected to the collection chamber side of the sieve mesh (60). Arrange the reinforcing member (70) of the sieve net (60),
In a wind sieving apparatus equipped with an air nozzle (36) for blowing backwash air to prevent clogging of the sieve net (60), the sieve net (60) is inverted on the supply chamber side of the sieve net (60). A wind sieving apparatus, comprising: a clogging prevention member (50) provided so as to come into contact with a sieve net (60) when being bent by blowing of washing air. 2. The wind sieving apparatus according to claim 1, wherein the clogging prevention member (50) comprises a net or a grid having a larger opening than the sieve net (60). 3. The wind sieving apparatus according to claim 1, wherein a plurality of sieve nets (60) are provided between the clogging prevention member (50) and the reinforcing member (70). 4. A screen between adjacent sieve screens (60),
The wind screen device according to claim 3, further comprising a clogging prevention member (50). 5. A sieve mesh structure used in a wind sieve device (10), which is provided between a raw material powder supply chamber (20) and a sieved powder recovery chamber (30), The sieve mesh (60) for sieving the powder has a clogging prevention member (50) on one surface and the other, so that the sieve mesh (60) comes into contact with the sieve mesh (60) when flexed. A sieve mesh structure in which a reinforcing member (70) is disposed on the surface of the sieve.