JPH0259076A - Apparatus for classifying particulate material - Google Patents

Abstract

PURPOSE:To enhance classification efficiency by preventing the introduction of coarse particles carried by an air stream into a classifying chamber and adjusting the introducing amount distribution of the air stream by arranging a classifying blade to the inlet part of the classifying chamber. CONSTITUTION:The powder thrown on a dispersing plate 108 is moved toward the peripheral edge part of the dispersing plate 108 by the centrifugal force accompanied by the rotation of the dispersing plate 108 and thrown out to the dispersing space between an inner cylinder 102 and a classifying blade 105 from the outer periphery of the dispersing plate 108 to fall downwardly through said space under its own wt. along with the gas colliding with the inner wall of the inner cylinder 102. The particles having a small particle size in said powder are passed through a lower door 106 to be carried by the classifying revolving air stream blown in the inner cylinder 102 to be introduced into a classifying chamber 107. Coarse particles having a large particle size not carried by the revolving air stream fall downwardly along the inner wall of the inner cylinder 102 to be discharged out of the system from the discharge chute 115 connected to the lower end of the inner cylinder. The powder carried by the revolving air stream is introduced into the cylindrical basket like classifying chamber 107.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a classifier for classifying coarse powder and fine powder from a pulverized product such as cement or cement raw material.

More specifically, the present invention relates to a classifier that accurately classifies powder particles into upper and lower particles of a constant particle size.

[Prior Art 1] The prior art will be explained by taking as an example a starch band classifier that has been conventionally used for classifying cement raw materials or cement tarinka powder.

As shown in Fig. 5, the starch band classifier consists of an outer cylinder l with a cone connected to the lower end of a cylindrical body with a sealed upper part, and an internally installed coaxial center with the outer cylinder l. An inner cylinder 2 with a shutter door 3 attached to the middle part of a cone part connected to the lower end of a cylindrical body with an open top, and an outer cylinder 1 that freely passes through the center of the ceiling and hangs down. A disc-shaped distribution disk 6 is mounted on the lower end of the rotating shaft 4, and a plurality of sorting blades 8 are installed on the periphery connected by a support fitting 7 so as to be rotatable in synchronization with the distribution disk 6. a sorting blade mounting board 9,
A fan blade 11 is provided between the ceiling of the outer cylinder and the upper end of the inner cylinder and is mounted on the rotating shaft, and a fan blade 11 is installed at the upper end of the inner cylinder so that it can move forward and backward through the outer cylinder wall l. ih being done
The air volume control valve 12 is composed of two baffle plates.

The flow of air inside the classifier is caused by the rotation of the main blade 1 due to the rotation of the shaft 4.
1 generates a swirling upward flow 16 in the inner cylinder 2 and a swirling downward flow 17 in the outer cylinder l, which are circulated through the shutter 3.

Powder pulverized by a pulverizer (not shown) is fed into a feeding chute 13 that is suspended on the same axis as the rotating shaft.

As shown in FIG. 5, the charged raw material powder falls from the chute 13 onto the dispersion plate 6 which is being rotated by the drive device 18, moves on the dispersion plate 6 by centrifugal force, and is then moved onto the dispersion plate 6 by the centrifugal force.
is thrown horizontally from the periphery toward the inner cylinder wall. The thrown out powder blows up through the shutter 3 and is dispersed in a swirling upward flow 16, and coarse powder with a large particle size falls downward due to gravity and is discharged from the coarse particle discharge port 14. Powder with an intermediate particle size moves upward on the swirling upward flow 16 at a slow speed, so it collides with the sorting blade 8, is thrown onto the inner cylinder wall, and falls downward due to gravity, and is disposed of in the inner cylinder 2. The coarse particles are discharged from the machine through a discharge chute 14 provided at the lower end.

The fine powder that passes through the sorting blade 8 and rises with the airflow is
Fan blade 11 attached to the top of sorting blade 8
While being given a swirl, the air is guided into the space between the outer cylinder 1 and the inner cylinder 2 as a swirling descending m l 7, and is separated from the airflow by centrifugal force. The airflow is circulated into the inner cylinder through the shutters, and the fine powder is discharged as a product from the discharge chute 15 provided at the lower end of the outer cylinder l.

[Problems to be Solved by the Invention] In the conventional device, the raw material powder is dispersed in a narrow space between the dispersion plate 6 and the vertical wall of the inner cylinder 2, as shown in FIG.
The powder concentration in this space becomes high and the dispersion of the powder is inhibited, and the fine powder with a particle size below the particle size to be classified is not separated as coarse powder or fine powder and cannot ride the swirling upward flow 16 and is separated as coarse powder, so-called A phenomenon in which fine powder gets trapped occurs. As a countermeasure, if the in-cylinder air velocity is increased more than necessary, a portion of the coarse powder larger than the particle size to be classified will pass through the sorting blade 8 and be collected together with the fine powder. A so-called coarse powder straying phenomenon occurs. As a result, the classification efficiency deteriorates and the amount of repetition to the crushing system increases, which is a main factor in increasing the power consumption of the crushing system.

The present invention relates to an improvement of such a classifier, which solves the above problems and improves classification efficiency. We have developed a classifier that is easy to operate.

In other words, as a result of our studies for the above purpose, we found a structure in which the housing of the classifier has a triple structure, a rotating shaft is suspended from the center of the housing, and a cylindrical cage with classification blades arranged around the circumference of this rotating shaft is provided. We have developed a classifier with high classification efficiency.

The present invention aims to provide such a classifier.

[Nido Stage 1 for Solving the Problems The present invention provides the following features: l) The housing of the classifier is composed of an outer cylinder lot for separating products, an inner cylinder 102 for coarse powder, and an auxiliary inner cylinder 103, as shown in FIG. It has a triple structure, and a shutter 106 is provided in the cylindrical part of the inner cylinder 102 to introduce airflow for classification into the inner cylinder 102 from the outside.

2) A cylindrical cage-shaped classification chamber 107 with a large number of classification blades 105 attached to the circumference facing the opening of the shutter 106 is provided.

3) The classification blade 105 is divided into many parts along the cylindrical cotton, and the upper and lower ends are respectively supported by support rings 108 and 10.
Further, each classification blade 105 can be freely changed in its mounting angle around its own vertical axis, and can be set to an arbitrary rotation angle of the blade. Furthermore, it is divided into a plurality of stages in the vertical direction, and the turning angle of each stage can be set independently.

4) The upper and lower support rings each have radial spokes 1
10.111 to the depending shaft 112.

5) The upper support ring 108 also serves as a dispersion disk for the raw material powder, and forms a dispersion chamber space 113 in both stages between the upper surface of the dispersion section of the dispersion disk and the upper end of the inner cylinder 102. The outer periphery of the distribution disk faces the gap between the inside of the inner cylinder 102 and the outside of the classification blade 105.

6) Raw material powder supply device 1 having an outlet that passes through the outer cylinder 101 and the inner cylinder 102 and supplies the raw material powder onto the dispersion disk.
14 is installed in at least one place. When installing in two or more locations, install them at equal intervals on the circumference of the distribution board.

7) An inverted conical auxiliary inner cylinder 103 is installed below the first classification blade lower support ring 109 to discharge coarse powder that has strayed into the product side and to prevent the classification airflow from making a short pass.
is installed at the lower part of the inner cylinder 102.

"Operation 1 The operation of the present invention will be explained based on the embodiment shown in FIGS. 1 to 3.

Fig. 1 is a longitudinal sectional view of the classifier of the present invention, Fig. 2 is a view taken along the line A-A in Fig. 1, and Fig. 3 is a view taken along the line B-B in Fig. 1. The powder pulverized by the pulverizer is fed onto the dispersion plate 108 via the powder raw material supply device 114.
The powder on the dispersion disk 108 moves toward the periphery of the dispersion disk 10B due to the centrifugal force accompanying the rotation of the dispersion disk 1, and is thrown out from the outer periphery of the dispersion disk into the dispersion space between the inner cylinder 102 and the classification blade 105. The thrown powder is in the inner cylinder! The inner cylinder 102 and the classification blade 105 collide with the inner wall of 02 or due to their own weight.
It falls downward through the space between.

The small internal particles are introduced into the classification chamber 107 along with the swirling airflow for classification that is blown into the inner cylinder 102 through the shutter 106 .

Coarse powder with a large particle size that is not entrained in the swirling airflow for classification falls downward along the inner wall of the inner cylinder 102 and is discharged from the system through a discharge chute 115 connected to the lower end of the inner cylinder. The powder entrained in the swirling airflow is transferred to a cylindrical cage-shaped classification chamber 1.
Introduced in 2007.

One classification blade 105 is installed on the outer periphery of the classification chamber 107. The number and installation angle of the classification blades 105 are determined by factors such as the capacity of the classifier, the rotational speed of the dispersion plate, the air volume of the circulating air stream for classification, and the separation particle size of the powder. When the classification airflow carrying powder is introduced into the classification chamber 107, the powder moves at different speeds depending on the particle size, and powders with large particle sizes that move slowly collide with the classification blades 105 and are bounced out of the classification chamber. It is blown away, falls downward along the inner cylinder wall, and is discharged as coarse powder to the outside of the yarn through the discharge chute 115. Among the powders introduced into the classification chamber 107, the stray coarse powders are separated by inertia and gravity when the classification airflow changes from a swirling horizontal flow to a swirling upward flow, and fall into the auxiliary inner cylinder 103. It is discharged from the discharge port 115.

The airflow passing through the classification chamber and rising is introduced between the outer cylinder 101 and the inner cylinder 102 while being given a swirl by the rotation of the fan blade 116 mounted on the rotation shaft +12. This airflow separates the powder by centrifugal force, and the shutter 106
It is circulated to the classification chamber 107 through the classification blade 105. On the other hand, the separated powder falls downward along the inner wall of the outer cylinder 101 and is taken out as a product by a discharge shoe 117 connected to the lower end of the outer cylinder 101.

The mounting angle of each of the classification blades 105 is
If the outer end of the classification blade is upstream of the rotational direction of the support ring 109, the separation particle size will increase, and the separation will increase as it goes downstream, starting from the radius line connecting the center of the attachment part of the 05 and the center of the support ring 109. The particle size becomes small (in other words, if the installation angle of the 1st classification blade 105 is set to the downstream side, the airflow for classification taken into the classification chamber becomes difficult to take in due to the resistance of the blade, so the separated particle size becomes small. 6. The classification blade 1
If the number of 05 plates installed is increased, the particle size per separation will become smaller, and if the circulating air volume for one classification is reduced, the particle size per separation will be reduced.

It is preferable to increase the number of vertically divided stages of the rotor door 106i5 and the classification blade 105, and make it possible to change the mounting angle of each stage, since this allows the fluid for classification to be taken uniformly into the classification chamber. be.

The position of the shutter 106 attached to the inner cylinder 102 should be determined depending on factors such as the distance between the dispersing disk and the inner cylinder, the rotation speed of the dispersing disk during powder processing of the classifier, etc. It needs to be lower.

Further, it is preferable to increase the number of vertical division stages of the shutters 106 because the vertical angle of the airflow for classification can be adjusted and the classification efficiency can be improved depending on the conditions.

[Example J Using the example apparatus shown in FIG. 1, an experiment was conducted to classify pulverized cement clinker powder having a particle size distribution shown in Table 1 as a powder for classification.

What are the specifications of the classifier used in the experiment?

Classifier outer cylinder diameter: 4880mmφ Classifier inner cylinder diameter: 4200mmφ Upper support ring diameter: 2800mmφ Lower support ring diameter: 2800mmφ Classifier blade width and length: 200mm x 400mm or more, 1 classifier load 35T/H, rotation of the rotating shaft The experiment was conducted with the number of the classification blades being 20 rpm, the number of stages in which the classification blades were installed in three stages (upper and lower), and the installation angle was 15 degrees downstream with respect to the rotational direction with the lower support ring radius line as the starting point. A cooling air intake duct (not shown) was installed in the auxiliary inner cylinder, and an air bleed tact and dust collector were installed in the upper part of the outer chamber.The results are shown in Figure 4. In FIG. 4, the horizontal axis shows the particle diameter, and the vertical axis shows the distribution ratio to the coarse powder side with a dotted line.

As a comparative example, a test was conducted using a starch band classifier having the same outer cylinder and inner diameter under the same load as the above test, and the results are shown by solid lines in FIG.

As a result, it was confirmed that the classification line was sharper and the classification efficiency was improved compared to the conventional classifier.

[Effects of the Invention] By using the device of the present invention, the following excellent effects can be obtained6? I was approved.

Since the contact space between the powder dispersed in the classifier and the air stream for classification becomes wider, the speed of the air stream passing through the dispersed powder becomes slower. Therefore, fewer coarse particles are transported into the classification chamber, and the phenomenon of coarse particles straying into the product is reduced (thereby, the efficiency of one classification is increased and the quality of the product is improved).

By installing a classification blade at the entrance of the classification chamber, it is possible to prevent coarse particles entrained in the airflow from being introduced into the classification chamber, and to adjust the distribution of the amount of airflow introduced, improving classification efficiency. This is a contributing factor.

In the apparatus of the present invention, it is possible to perform primary classification using an air current, secondary classification using a first classification blade, and tertiary classification using a change in the direction of the air flow, and it is possible to increase the number of opportunities for single classification compared to conventional classifiers.

Further, an existing conventional classifier can be easily modified to the classifier of the present invention.

Since the classification efficiency is improved, the classification load can be increased compared to conventional classifiers.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the classifier of the present invention, FIG. 2 is a view taken along the line A-A in FIG. 1, FIG. 3 is a view taken along the line B-B in FIG. FIG. 5 is a longitudinal cross-sectional view of a conventional classifier. 101... - Outer cylinder, 102... Inner cylinder, 103... Auxiliary inner cylinder, XO5... Classifying blade, 10th... Armor door, 107... Classifying room, 108... Upper support Ring and distribution plate, 109... Lower support ring, 110... Spoke, III... Spoke, 112... Vertical axis,
113--dispersion chamber, l[4--raw material powder supply device,
115...Discharge chute, 116...Fan blade,
117...Discharge chute, 118...Swirling airflow, 1
20...Rotating motor.

Claims (1)

[Scope of Claims] 1. An outer cylinder in which a cone portion is connected to the lower end of an upright cylindrical body with a sealed top end, and a cone portion connected to the lower end of an upright cylindrical body with an open top end. A classifier equipped with a concentric inner cylinder, and a plurality of fan blades mounted near the top of the outer cylinder on a rotating shaft penetrating the top of the outer cylinder and hanging down. A large number of armored doors are installed in the cylindrical portion of the tube to communicate the inside and outside of the inner cylinder, and a classification blade is provided facing the armored door with a gap on the inner diameter side of the armored door, and the classification blade is configured to rotate as described above. The upper and lower ends are fixed to ring-shaped upper and lower support rings attached to the shaft, and the upper surface of the upper support ring has a ring-shaped distribution disk, and the outer periphery of the distribution disk faces the gap between the shutter and the classification blade. and an auxiliary inner cylinder is disposed below the lower surface of the lower support ring and spaced inside the inner cylinder. 2. Claim 1, characterized in that the classification blades are mounted so that they can be set at arbitrary mounting angles around their respective vertical axes.
The classification device for powder and granular materials described above.