JPH0261318B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a centrifugal classifier for classifying powder and granular materials, particularly fine powder and granular materials. What is the granular material mentioned here?
It refers to fine particles of 300 mesh or less (particle size of 44μ or less), and examples of this type of material include fine ceramics and reinforced plastics.

BACKGROUND TECHNOLOGY Typical centrifugal classifiers of this type that have been known in the past include seventh and eighth centrifugal classifiers.
There are some as shown in the figure, which will be briefly explained.

This classification device has a hollow body 31, and an exhaust port 33 is provided approximately in the center of the top wall of a classification chamber 32.
Four horizontal classification impellers 35 are provided at equal intervals in the circumferential direction in a circular impeller chamber 34 provided surrounding the exhaust port 33, and these impellers 35 are driven by a drive device (not shown). The impeller 35 is designed to rotate at high speed, and an exhaust pipe 36 is provided at the tip of the impeller 35 to communicate the exhaust port 33 and the impeller chamber 34 . A powder supply member 37 is provided on the wall of the classification chamber 32 below it, a funnel-shaped part 38 is formed below it, and a deflecting member consisting of a funnel-shaped part and a cylindrical part is provided inside this part. 41 has been installed. A primary air pipe 40 containing a swirling vane 39 is connected to the lower part of the classification chamber 32, and a funnel-shaped coarse particle chamber 42 is formed at the lower part of the primary air pipe 40.

In such a device, the powder and granules supplied by the supply member 37 fall downward in the classification chamber 32, and the coarse particles fall directly into the coarse particle chamber 42, but the remaining particles are absorbed by the primary air. It is supplied from the pipe 40, rectified by the swirling vane 39, swirls in the deflecting member 41, and mixes with the rising gas to form a mixed air flow e'. When this air flow e' exits the deflecting member 41, four It separates into a mixed air flow f' and rises toward each impeller 35. And this impeller 35
The fine particles are separated into fine particles and coarse particles according to the separation limit based on the rotation speed, and the fine particles are discharged to the outside from the exhaust port 33 through the impeller 35 and the exhaust pipe 36 along with the air flow p', and the coarse particles are discharged from the impeller 35 and the exhaust pipe 36. The air is blown outward by the swirling air current m' around the air 35, descends along the wall surface of the classification chamber 32, and is again subjected to the above-mentioned classification action at the primary air pipe 40. The particles and fine particles reach the coarse particle chamber 42 and the exhaust port 33, respectively, as described above.

However, in such a conventional device, since adjacent impellers 35 are located in the same space of one impeller chamber 34, the airflow generated by each impeller 35 interferes with each other, resulting in poor classification accuracy. There is a drawback. This cannot be avoided even if the adjacent impellers 35 rotate in the same direction or in opposite directions.To avoid this, it is possible to increase the distance between each impeller, but this is determined by the processing air volume. An impeller 35 is installed inside the device body which has a volume.
This is contrary to the idea that all of the above should be arranged in a compact manner, and is impossible to achieve. In addition, the top wall of the impeller chamber 34 is flat, and a large space is formed above the impeller 35.
There was also a drawback that particles were suspended in this space and deposited on the upper part of the exhaust stack 36.

Problems to be Solved by the Invention The purpose of the present invention is to eliminate the drawbacks of the conventional classifier as described above, and to make the airflow generated by each impeller compact without increasing the distance between the impellers. It is an object of the present invention to provide a classification device that can improve the classification accuracy without causing mutual interference while keeping the particles together, and further prevents particles from floating in the upper space of an impeller chamber.

In addition to the above-mentioned objects, the second object of the present invention is to provide a classification device in which the installation and replacement of the exhaust port is easy, and the gap between the exhaust pipe and the impeller is easy to adjust. be.

Means for Solving the Problems In the first aspect of the present invention, in order to achieve the above-mentioned object, the individual classification impellers are separated by partition walls and housed in independent impeller chambers, The top wall of the impeller chamber has an arc shape that is approximately concentric with the circumference of the impeller, and a rectifying plate is further provided at the lower part of the air flow descending side of the impeller chamber. It is.

Next, in order to achieve the above-mentioned object, the second aspect of the present invention is characterized in that, in the first aspect, the exhaust pipe and the exhaust port are connected to each other by a flexible hose.

Effects In the first invention as described above, a mixed air flow in which powder and granules are mixed with suction air is supplied into the body from the primary air pipe, rises in the classification chamber, and is separated from each blade by the partition wall. The impellers are respectively introduced into the vehicle compartments, and the impellers are rotated at high speed within the impeller compartments. Therefore, part of the above-mentioned rising airflow becomes an exhaust flow and is discharged outside from the exhaust port through the impeller, and the other part becomes a swirling flow due to the high speed rotation of the impeller and rises on one side of the impeller chamber. Afterwards, it descends along the top wall of the arc-shaped impeller chamber. During this time, the swirling flows in adjacent impeller chambers do not interfere with each other due to the partition wall. In this way, fine particles with a small mass in the air mixture flow are discharged from the exhaust port along with the exhaust flow, and coarse particles with a large mass descend along with the swirling flow along the wall surface of the classification chamber. During this descent, the particles are given a swirling force by the baffle plate below the impeller chamber, and descend while rotating in a fixed direction.As a result, each layer of coarse particles, coarse particles, and fine particles is arranged in an orderly manner in the descending particle group. form a layer of particles.

Next, in the second invention, the first invention as described above
In the invention, the gap between the exhaust tube and the impeller is adjusted by inserting the exhaust tube into the flexible hose or removing it from the flexible hose, thereby adjusting the gap between the exhaust tube and the impeller. This compensates for any misalignment of the axis.

Embodiment In the embodiment shown in FIGS. 1 to 5, 1 indicates a hollow body, and the upper part of this body 1 has a classification chamber 2.
However, a coarse particle chamber 12 is also formed in the lower part.

A plurality of impeller chambers 4 (four in the drawing) are provided in the upper part of the classification chamber 2.
These impeller chamber groups 17 are arranged facing each other with a space 20 between them (Fig. 3), and a partition wall 16 is provided between them. An impeller chamber 4 is formed vertically on both sides of the impeller chamber 4 (FIG. 2), and inside this impeller chamber 4 is a horizontal classification impeller 5 that is rotated at high speed by a drive device (not shown). The rotating shaft 21 is installed so as to be parallel to the partition wall 16, and the top wall 18 of the impeller chamber 4 has an arcuate shape substantially concentric with the impeller 5. In this embodiment, the impeller 5 rotates in opposite directions for each impeller chamber group 17, as shown by the arrow m in FIG. As will be described later, the arrow m indicates the flow direction of the swirling airflow in the impeller chamber 4, and a rectifying plate 19 is provided at its descending end and inclined in a direction to swirl the airflow in the same direction. (See also Figure 5).

Reference numeral 3 denotes an exhaust port, through which air is sucked by an exhaust fan 7, and particulates contained in this air are collected by a dust collector 9. This exhaust port 3 is removably installed in the upper part of the body 1 in the space 20 between the impeller groups 17, and 6 is an exhaust pipe, which is removably installed in the wall opening of the impeller chamber 4 facing the outlet of the impeller 5. The members 3 and 6 are mounted with a gap a between them and the impeller 5 (FIG. 6), and the tips of both members 3 and 6 are placed facing each other with a gap between them and are connected by a flexible hose 22. Note that the exhaust pipe 6 is provided with a purge air inlet 25.

A funnel-shaped part 8 is formed in the lower part of the classification chamber 2, and a plurality of annular secondary air ports 23-1, 23 are formed on the wall surface of the funnel-shaped part 8.
-2...23-n is provided, this secondary air port is formed by connecting the upper and lower body members with a plurality of connecting members 13, and the coarse particle chamber 12 is located below the funnel-shaped part 8. A primary air pipe 10 having an opening 24 at the top is disposed inside the primary air pipe 10, and a secondary air port 23 is also provided on the wall of the coarse particle chamber 12 above the opening 24. There is. The other end of the primary air pipe 10 is open to the atmosphere, and powder and granules are supplied from a powder and granule supply device 11 . Further, an airtight device (not shown) is provided at the bottom of the coarse particle chamber 12.

When performing classification work in the above-mentioned device, air is sucked through the opening of the primary air pipe 10 by operating the exhaust fan 11, and powder and granules are supplied from the supply device 11 into this air flow. A mixed airflow in which the powder and granules are mixed with air is supplied from the primary air pipe 10 into the body 1, becomes an upward airflow e, and rises inside the classification chamber 2, and then passes through the partition wall 16 as shown in FIG.
is divided into four rising air currents f, each of which is introduced into different adjacent impeller chambers 4. A part of these airflows f becomes an exhaust flow p and is discharged from the exhaust pipe 6 toward the exhaust port 3 through the impeller 5 rotating at high speed, and the other part becomes an exhaust flow p. The impeller chamber 4 becomes a swirling flow.
After ascending on one side of the chamber 4, it becomes a downward flow m along the inner surface of the arc-shaped top wall 18 and descends within the same chamber 4.

The exhaust flow p includes small particles of small mass in the air mixture flow f, and the exhaust flow p includes particles having a small mass in the air mixture flow f, and the particles are passed from the exhaust port 3 to the dust collector 9.
The airflow and fine particles are separated here, the fine particles are collected as a product, and the airflow is discharged to the exhaust fan 7, and coarse particles with a large mass are included in the downward flow m and are carried along the wall of the classification chamber. It will descend. During the downward movement, this downward flow m collides with a rectifier plate 19 provided at the lower limit position of the impeller chamber 4,
As shown in FIG. 5, each current plate 19 applies a turning force in the clockwise direction as shown by the arrow in the drawing, and as a result, the particles descend while turning in the same direction. The particles, which had been descending in a chaotic manner regardless of the particle size, form a layer n (FIG. 1) in which each layer is arranged in an orderly manner from the outside to the inside: coarse particles, coarse particles, and fine particles.

In this way, a horizontal secondary air flow g is added from the secondary air port 23 by the rising air flow e to the coarse particle layer n descending in the classification chamber 2, and the fine powder in the coarse particle layer n is transferred to the air flow e. Therefore, it is pushed into the upward flow f, is included in the upward flow f again, and undergoes the above-mentioned classification operation, and the other coarse particles and coarse powder are transferred to this air flow g.
The particles descend toward the coarse particle chamber 12 without being affected by the

In the above case, as shown in FIG. 6, a uniform gap a (usually 1 mm or less) is required between the impeller 5 and the exhaust pipe 6, which also serves as a passage for air from the purge air inlet 25. By the way, this gap a needs to be corrected every time the impeller 5 is replaced, so a shim plate 26 is inserted between the outer wall of the impeller chamber 4 and the exhaust pipe 6, and the shim plate 26 closes the gap. In order to carry out such work, the exhaust port 3 and the exhaust pipe 6 are connected with a flexible hose 22, which also prevents misalignment between the exhaust port 3 and the exhaust pipe 6. Compensate.

In the embodiment described above, four impeller chambers 4 were provided, but two impeller chambers may be provided separately.

Effects of the Invention The first invention of the present invention is as described above, and the classification impeller is housed in an independent impeller chamber for each impeller, and the top wall of this impeller chamber is formed into a circle substantially concentric with the impeller. It has an arc shape, and a rectifying plate is installed at the bottom of the airflow descending side of the impeller chamber, so the airflow generated by each impeller does not interfere with each other, increasing classification accuracy. There is no need to provide a large-capacity impeller chamber, making it compact, and it also prevents fine particles from floating in the upper part of the impeller chamber. There are effects such as being able to align them.

Next, in the second invention of the present invention, in addition to the effects of the first invention, the exhaust pipe and the exhaust port are connected at the joint with a flexible hose, so that the impeller and the exhaust pipe are The gap can be easily adjusted, the assembly and replacement of the two parts is easy, and even if there is a misalignment between the openings of the two parts, this can be compensated for.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of an embodiment of the invention, and FIG.
The figure is a cutaway view taken along the - line of figure 1, and figure 3.
The figure is a slope view of the same impeller chamber as above, Figure 4 is a cutaway view taken along the - line of Figure 1, Figure 5 is a cutaway view taken along the - line of Figure 2, and Figure 6 is an outline of the thing shown in Figure 1. FIG. 7 is a vertical cross-sectional view of a typical conventional classification device, and FIG. 8 is a cross-sectional view taken along the - line in the same. 1... Hollow body, 2... Classification chamber, 3... Exhaust port, 4... Impeller chamber, 5... Classification impeller, 6...
Exhaust pipe, 8... funnel-shaped part, 10... primary air pipe,
12... Coarse particle chamber, 16... Partition wall, 18... Top wall of impeller chamber, 19... Current plate, 22... Flexible hose.

Claims (1)

[Claims] 1. An impeller chamber is provided in the upper part and an exhaust port is provided in the center thereof, a plurality of horizontal classification impellers are arranged in the impeller chamber, and the exhaust port and the impeller are communicated with each other through an exhaust pipe. A powder centrifuge with a primary air pipe provided below a hollow body that has a classification chamber in which a funnel-shaped part with an opening is formed at the bottom and a coarse particle chamber connected below the classification chamber. In a classification device, each classification impeller is separated by a partition wall and housed in an independent impeller chamber, and the top wall of this impeller chamber has an arc shape that is approximately concentric with the circumference of the impeller. A centrifugal classification device for powder and granular materials, further comprising a rectifier plate provided at the lower part of the airflow descending side of the impeller chamber. 2. An impeller chamber is provided in the upper part and an exhaust port is provided in the center thereof, and a plurality of horizontal classification impellers are arranged in the impeller chamber, and the exhaust port and the impeller are communicated with each other through an exhaust pipe, and an exhaust port is provided in the lower part. In a powder centrifugal classification device, a primary air pipe is provided below a hollow body which has a classification chamber formed with a funnel-shaped part having an opening and a coarse particle chamber connected below the classification chamber. The classification impellers are separated by a partition wall and housed in independent impeller chambers, and the top wall of this impeller chamber has an arc shape that is approximately concentric with the circumference of the impeller. A powder centrifugal classification device characterized in that a rectifying plate is provided at the lower part of the airflow descending side of the casing, and the exhaust pipe and the exhaust port are connected at a joint with a flexible hose.