JP3311318B2 - Sieve device with airflow classification function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for classifying powder, which comprises a coarse powder side including a particle size before and after 40 μm and a fine powder smaller than a particle size before and after 20 μm. And a sieve device for simultaneously separating efficiently.

[0002]

2. Description of the Related Art Conventionally, an apparatus for classifying powders is a vibrating sieve using a sieve for classifying whether or not the powder passes through a mesh, or an air classifier for classifying using a difference in falling speed of powder in an air stream. Etc. are known.

[0003] In the case of classifying powder using a sieve, if the mesh of the sieve mesh is large, the classification can be performed relatively easily. However, if the mesh is 40 μm or less, particularly 20 μm or less, clogging is likely to occur. It is difficult to classify large amounts of powder.

The airflow classifier is suitable for classifying powders having a particle size of 40 μm or less, particularly 20 μm or less.
When powders having a particle size of m or less are to be separated, there is a disadvantage that accurate classification cannot be performed, for example, powders having a particle size of 40 μm or more are sometimes mixed in the obtained powders having a size of 20 μm or less. Therefore, in order to separate powder having a size of 20 μm or less, it was necessary to use a classifier using a sieve mesh and an airflow classifier in combination.

However, when two types of classifiers are used together,
When the size of the equipment is increased, and when the material of the powder and the target particle size are switched, the number of parts requiring cleaning of the classifier increases, and there is a disadvantage that the maintenance management requires labor.

[0006]

SUMMARY OF THE INVENTION The present invention provides both a coarse powder side including a particle size before and after 40 μm as a reference and a fine powder side smaller than the particle size before and after 20 μm as a reference.
At the same time, the present invention has been completed by variously examining a classifier which can surely classify, has a small facility, and is easy to clean.

[0007]

According to the present invention, a shielding plate having a function of widely dispersing powder is provided below a sieve mesh, and the shielding plate is provided with a suction port for sucking gas from below the shielding plate. A sieve device having an airflow classification function, further comprising a fine powder suction mechanism further provided with a flow straightening plate below the suction port as required. The fine powder suction mechanism of the present invention requires a shielding plate having a function of widely dispersing the powder that has passed through the screen. The shielding plate has a function of preventing the powder from being directly sucked into the suction port, preventing the powder from falling as a group, and ensuring the conveyance of the fine powder by the air flow. Although various shapes of the shielding plate are conceivable, a conical shape is most preferable in order to disperse the powder most uniformly in a certain area.

Further, it is necessary that the shielding plate be provided with a suction port for sucking gas from below. Due to the suction of the gas, an air current is generated from the outer peripheral portion to the central portion of the shielding plate, and the fine powder is conveyed and separated by the air current. The particle size of the fine powder to be conveyed is determined by the speed of the airflow generated on the outer peripheral portion of the shielding plate. In order to keep this speed constant, the shape of the shielding plate is most preferably conical, and Most preferably, a suction port is provided near the lower central portion.

Further, in order to stabilize the speed of the air flow generated on the outer peripheral portion of the shielding plate, it is preferable to provide a rectifying plate below the suction port. By providing this rectifying plate, the airflow generated in the opening formed between the outer peripheral portion of the shielding plate and the rectifying plate is stabilized, and fine powder can be reliably separated. The following shapes of the current plate provided as necessary can be selected depending on the purpose.

In order to prevent the powder from remaining on the current plate, a convex shape may be used so that the powder moves to the outer periphery. In this case, the speed of the air flow increases as the air flow approaches the suction port, so that the fine powder is reliably sucked and separated.

When the current plate is formed in a concave shape, the speed of the airflow from the outer periphery of the shield plate to the suction port is reduced with respect to the speed of the airflow generated in the opening formed in the outer periphery of the shield plate and the current plate. it is possible, of the outer peripheral portion and the fine powder which is transported by a gas stream generated in the opening made form <br/> between the rectifier plate of the shielding plate, only finer powder is sucked into the suction port, the suction port The powder that has not been sucked into the plate will fall on the current plate and remain. By providing a recovery port in the current plate, the remaining powder can recover a powder having an intermediate particle diameter between the powder sucked into the suction port and the coarse powder. However, it is necessary that the port for collecting the powder be shut off from the outside air.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a portion of a vibrating sieve provided with a fine powder suction mechanism of the present invention.
1 is an overall schematic diagram. The raw material powder for classification is supplied from a raw material charging port (21), and is classified by a sieve net (2) into a powder (15) that has not passed through the sieve net and a powder (16 and 17) that has passed.

The powder (15) that has not passed through the sieve mesh passes through the outlet (13) at the top of the sieve mesh, and the powder on the mesh collection container (10)
Will be collected. The powder that has passed through the sieve net is classified into coarse powder and fine powder by a fine powder suction mechanism. That is, when the particles are widely dispersed by the shielding plate (3) and fall from the periphery thereof, the air flow classification function is performed by the flow of the air (18), and the particles are classified into the unsucked powder (16) and the sucked powder (17). Is done. The powder (16) which was not sucked is a current plate (19)
As a result, the powder is collected at the under-mesh powder discharge port (14), and is collected in the coarse-powder collection container (11) therethrough.

The sucked powder (17) flows into the atmosphere (1).
According to 8), the gas collects in the suction port (4) for sucking gas from below the shielding plate (3), passes through the suction pipe (5), enters the cyclone (7) connected by the hose (6), and enters the fine powder collection container. Collected in (12). The powder not recovered by the cyclone (7) is recovered by the bag filter (8).

An air flow (18) is formed by a blower (9) and passes through a raw material inlet (21) to a sieve screen (2).
And between the outer peripheral portion of the shielding plate (3) and the rectifying plate (19).
Passing through the opening formed in the. When passing through this opening, the airflow classification function works as described above.
Atmospheric flow (18) is discharged into the atmosphere from the final blower (9) through the suction port (4).

In the sieve device having the air flow classification function, when clogging occurs in the sieve mesh (2) due to a large amount of raw material powder being input, a large negative pressure is generated below the sieve mesh (2). Since the sieve net (2) may be damaged, the over-negative pressure prevention port (2) is inserted into the sieve frame (1) as a safety device.
0) is provided.

In the sieve device having the air flow classification function of the present invention configured as described above, the mesh of the sieve net (2): 45 μm The shape of the shielding plate (3): conical, inclination angle 10 degrees Diameter: 680 mm Diameter of the sieve frame (1): 800 mm Airflow velocity generated in an opening formed in the outer periphery of the shielding plate (3) and the rectifier plate (19): 14 m / S The copper powder of 75 μm or less was classified under the conditions of 14 m / S 2. As a result, the particle size distribution of the raw material powder and the powder that passed through the net outlet (14) was measured, and the results are as shown in Table 1.

[0018]

[Table 1] From Table 1, it can be seen that the sieve device of the present invention can reliably classify both the coarse powder side and the fine powder side.

[0019]

As described above in detail, the sieve device having the airflow classification function of the present invention is provided in the same installation place as the conventional sieve device, and has a coarse powder having a particle size before and after 40 μm. The efficient classification can be achieved by simultaneously and reliably classifying both the powder side and the fine powder smaller than the particle size before and after 20 μm. In addition, since the cleaning can be performed by the same method as the conventional sieving apparatus, many kinds of raw material powders can be classified by one apparatus, and there is an effect that the operation rate of the classifier is improved.

[Brief description of the drawings]

FIG. 1 is a schematic view of a sieve portion when a fine powder suction mechanism of the present invention is provided in a vibrating sieve machine.

FIG. 2 is an overall schematic diagram of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sieve frame 2 ... Sieve net 3 ... Shielding plate 4 ... Suction port 5 ... Suction pipe 6 ... Hose 7 ... Cyclone 8 ... Bag filter 9 ... Blower 10 ・ ・ ・ On-mesh powder collecting container 11 ・ ・ ・ Coarse powder collecting container 12 ・ ・ ・ Fine powder collecting container 13 ・ ・ ・ On-mesh powder outlet 14 ・ ・ ・ On-mesh powder outlet 15 ・ ・ ・Powder which did not pass 16 ・ ・ ・ Powder which was not sucked 17 ・ ・ ・ Powder which was sucked 18 ・ ・ ・ Air flow 19 ・ ・ ・ Rectifier plate 20 ・ ・ ・ Excessive negative pressure prevention port 21 ・ ・ ・ Input of raw material Port A: An opening formed between the outer periphery of the shielding plate and the current plate

Claims (3)

(57) [Claims] 1. A fine powder suction mechanism having a shielding plate having a function of widely dispersing powder under a sieve mesh and having a suction port for sucking gas below the shielding plate. , A sieve device with airflow classification function. 2. A shielding plate having a function of widely dispersing powder is provided below the sieve net, a suction port for sucking gas is provided below the shielding plate, and a rectifying plate is provided below the suction port. A sieve device having an air flow classification function, characterized by having a fine powder suction mechanism provided with a filter. 3. The air flow classification function according to claim 1, wherein the shielding plate has a conical shape, and the shielding plate is provided with a suction port near a central portion below the shielding plate. Sieve device.