JP2567821Y2 - Pneumatic classifier - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic classifier.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a vertical mill, in which a crushing material 3 from a crushing material input chute 2 inserted into a casing 1 is crushed by a rotary driving device 4 and a crushing table 5 is provided.
Between the crushing groove 6 formed in the circumferential direction of the upper surface and the crushing roller 9 which is supported by the bracket 8 connected to the pressing-down device 7 and rotates while following the crushing table 5 while being pressed against the crushing groove 6. Pulverized, and powder 3 ′ produced by the pulverization is
A plurality of pneumatic classifiers 13 are blown up and conveyed by conveying air 12 from a blowing port 11 formed in an annular shape so as to surround the outer periphery of the pulverizing table 5 and guided to a pneumatic classifier 13 provided at an upper portion. The fine powder 10 is sent out from a fine powder duct 15 provided at the top, and the coarse powder 10 'is separated into a hopper-like guide plate 16 having a plurality of slits in the circumferential direction. To return to the center of the crushing table 5.

The classifying blades 14 of the pneumatic classifier 13 are:
The lower end is attached to the outer periphery of the upper surface of the rotating plate 17 at equal intervals, and the upper end is integrally connected by a connecting plate 18 having an opening 18 a. The rotating plate 17 and the connecting plate 18 can transmit torque to a drive motor 19. The powder 3 ′ rotatably supported by the drive shaft 20 connected to the casing 1 and conveyed above the casing 1 is classified by passing between the rotating classifying blades 14, that is, the rotating classifying blade. The passage of the coarse powder 10 ′ is prevented by 14, so that only the fine powder 10 can be passed.

[0004] There are two types of conventional classifying blades 14: a backward type as shown in FIG. 4 and a radial type as shown in FIG. 5. The powder 10 ′ is prevented from passing by being rejected by the classifying blades 14, and the latter radial type puts the coarse powder 10 ′ to be passed on the swirling flow generated by the rotation of the classifying blades 14 and uses centrifugal force. It is designed to prevent passage.

[0005]

The backward type has an advantage that it can be used with low rotation and low power, and is often used for classification of about 10 to 100 μm. In the case of classifying), the number of rotations or the number of blades must be increased.

However, since the backward type classifying blades 14 are mounted at an angle as shown in the figure,
When the number of rotations was increased, the torsional moment applied to the classifying blades 14 was increased and the strength was not increased, and the number of rotations could not be simply increased.

Further, when the number of blades is increased, in the case of the backward type, since the classification blades 14 have an angle with respect to the radial direction, the powder 3 'once flowing between the blades is discharged to the outside. This is disadvantageous in that the powder 3 'is more likely to adhere to the rear surface of the classifying blade 14 and the operation cannot be continued.

On the other hand, the radial type has the advantage that the powder 3 'is less adhered and the strength is more advantageous than the backward type described above, but on the other hand, it has to be used at high rotation speed and high power, so that it is consumed. There is a disadvantage that the cost of power is increased.

The present invention has been made in view of the above-mentioned circumstances, and provides a pneumatic classifier having both advantages of a backward type and a radial type.
It aims to offset the disadvantages of the backward type and the radial type.

[0010]

SUMMARY OF THE INVENTION According to the present invention, powder entrained by carrier air is introduced from the outer periphery of a plurality of rotating classifying blades into fine powder passing through the classifying blade and coarse powder blocked from passing. In a pneumatic classifier for classifying, the classifying blades are arranged radially with respect to the center of rotation, and an inclined surface that cuts inward in the direction of rotation is formed at an outer end of the classifying blade. It relates to a classifier.

[0011]

Therefore, according to the present invention, when the classifying blade is rotated to introduce the powder entrained in the carrier air from the outer periphery of the classifying blade, the powder rides on the swirling flow generated by the rotation of the classifying blade and generates a centrifugal force. A coarse powder having a relatively small particle size, which is classified into fine powder and coarse powder and tends to flow into the inside of the classification blade together with the carrier air against the centrifugal force, was formed at the outer end of the classification blade. It is repelled outward by the inclined surface.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention. In the drawings, the same reference numerals as those in FIG. 3 denote the same parts.

In the figure, reference numeral 21 denotes a vertical mill having substantially the same configuration as the above-described vertical mill shown in FIG. 3, and reference numeral 22 denotes a pneumatic classifier of the vertical mill 21. The classifying blades 23 of the pneumatic classifier 22 are shown. Are arranged radially with respect to the rotation center 24, and an inclined surface 25 that cuts inward in the rotation direction (the direction indicated by the arrow A in FIG. 2) is formed at the outer end thereof.

When the vertical mill 21 is operated to perform classification by the pneumatic classifier 22, a swirling flow is generated by the rotation of the classification blades 23, and the swirl flow is accompanied by the conveying air 12 to lower the vertical mill 21. Powder 3 ′ rising from the air is classified into fine powder 10 and coarse powder 10 ′ by the centrifugal force on the swirling flow, and the powder 3 ′ is separated from the classification blades 23 together with the carrier air 12 against the centrifugal force. Coarse powder 1 with relatively low particle size that is going to flow inward
0 ′ is repelled outward by an inclined surface 25 formed at the outer end of the classifying blade 23.

Therefore, according to the above-described embodiment, while making use of the advantages of the conventional radial type, which has little adhesion of the powder 3 'and is advantageous in terms of strength, it has a repelling effect similar to that of the backward type. Can be added, the same classification performance can be achieved at a lower rotational speed than the radial type as compared with the radial type having the same number of classification blades, and the cost of power consumption can be significantly reduced. Can be.

Also, when compared with a radial type having the same number of classifying blades at the same rotational speed, the classifying performance can be greatly improved with the same power consumption.

Further, since the classifying blades 23 are radially attached to the center of rotation, the strength is strong, and there is no problem that the powder 3 'adheres to the back surface of the adjacent classifying blades 23. There is no limitation on the number of rotations and the number of blades as in the backward type, and the classification performance can be further improved by increasing the number of rotations or the number of blades.

The pneumatic classifier according to the present invention is not limited to the above-described embodiment, but may be installed downstream of various pulverizers in addition to the pneumatic classifier provided on the upper part of the vertical mill. That it can also be used as a pneumatic classifier provided separately,
In addition, it goes without saying that various changes can be made without departing from the scope of the present invention.

[0020]

According to the pneumatic classifier of the present invention, various excellent effects as described below can be obtained.

(I) A repelling action such as a backward type can be added while taking advantage of a conventional radial type having little powder adhesion and being advantageous in strength. The same classification performance can be achieved at a lower rotational speed than the radial type as compared with the radial type having the same number of classification blades,
Power consumption costs can be significantly reduced.

(II) Compared with a radial type having the same number of classifying blades at the same rotational speed, the classifying performance can be greatly improved with the same power consumption.

(III) Since the classifying blades are mounted radially with respect to the center of rotation, the strength is high, and coarse powder is repelled on the inclined surface at the outer end of the classifying blades. Since there is no problem that the rejected coarse powder is blocked by other adjacent classifier blades and cannot be removed on the outer periphery, there is no limit on the number of blades or the number of blades as in the conventional backward type, and the number of blades can be increased. The classification performance can be further improved by increasing the number of blades.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a view in the direction of arrows II-II in FIG.

FIG. 3 is a cross-sectional view showing an example of a conventional pneumatic classifier provided on an upper part of a vertical mill.

FIG. 4 is a plan sectional view showing a conventional backward type pneumatic classifier.

FIG. 5 is a plan sectional view showing a conventional radial type pneumatic classifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fine powder 10 'Coarse powder 12 Conveying air 22 Pneumatic classifier 23 Classification blade 24 Rotation center 25 Slope

Claims (1)

(57) [Scope of request for utility model registration] 1. A pneumatic classifier that introduces powder entrained in carrier air from the outer periphery of a plurality of rotating classifying blades and classifies the fine particles into fine particles passing through the classifying blades and coarse particles blocked from passing therethrough. A pneumatic classifier, wherein the classifying blades are arranged radially with respect to the center of rotation, and an inclined end surface is formed at the outer end of the classifying blades so as to cut inward in the direction of rotation.