JPS62241559A - Rotary type separator for vertical type crusher - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotary separator for a vertical pulverizer for pulverizing cement raw materials, coal, chemicals, etc.

[Prior Art] A vertical pulverizer equipped with a rotary table and a pulverizing roller is widely used as a type of pulverizer that finely pulverizes granules such as cement raw materials, coal, and chemicals into powder. This type of crusher consists of a disk-shaped rotary table that is driven by a motor with a reducer to rotate at low speed in the lower part of a cylindrical casing, and a part that divides the outer circumference of the upper surface into equal parts in the circumferential direction, which is pressed by hydraulic pressure or the like. It is equipped with a plurality of rollers that are driven to rotate.

For example, in FIG. 5 showing a conventional vertical crusher, the crusher, which is designated as a whole by reference numeral 1, is visually formed as a single tower body, and the base of the crusher has an electric motor 2 and a speed reducer 17.
A rotary table 3 rotated by a rotary table 3 is disposed.

A plurality of conical crushing rollers 4 are arranged to rotate in sliding contact with the rotary table 3, and the crushing rollers 4 are rotatably supported on a support arm 5. The support arm 5 is fixed to a support shaft 6 rotatably supported on the crusher side. Further, one end of a rotating arm 7 is fixed to this support shaft 6, and this rotating arm 7 extends downwardly through the side of a casing 8 surrounding the rotating table 3, and extends between the lower chambers of the crusher. It's coming. The lower end of this rotating arm 7 is connected to a rod 1 of a pressure cylinder 9 whose lower end is rotatably supported on the base of the crusher 1.
It is rotatably supported on the tip of 0.

Then, the granules as raw materials supplied to the center of the rotary table 3 through a supply pipe (not shown) are caught between the driven roller 4 and the rotary table 3 by rotation of the table, and are pulverized. On the other hand, hot air is guided into the casing 8 by a duct (not shown), and this hot air blows up from the annular space 14 between the outer peripheral surface of the rotary table 3 and the inner peripheral surface of the casing 8. The fine powder rises inside the crusher 1 while being dried, and is discharged from the discharge pipe 16 as a mixture with hot air and sent to the next process.

Note that some of the coarse particles also rise within the crusher 1, but are classified by the rotating blades 15 of the upper separator and returned onto the rotating table 3.

As can be seen from the cross-sectional views shown in Figures 6 and 7, one type of separator that is widely used has a rotating shaft in the classification section, and the cross-sectional shape is L.
A plurality of letter-shaped rotating blades 15 are arranged radially in the longitudinal direction and fixed to the rotating shaft at equal pitches, and are rotated together with the shaft at an arbitrary number of rotations.

[Problems to be Solved by the Invention] In the so-called rotary separator configured as described above, the inflow air volume and inflow velocity of the dust-containing airflow passing between the rotary blades and the particle size distribution.

Even if the rotation speed of the separator is constant and does not change, the slope of the classification point of the classification performance characteristic curve is gentle as shown in Figure 8, and the classification accuracy, in other words, the sharpness of classification, is not so great. , ie. This indicates that there is a large amount of coarse powder mixed in with the fine powder, and that there is not a small amount of fine powder mixed in with the returned powder.

Therefore, the quality of the refined powder is low, and the poor classification accuracy causes negative effects such as a decrease in the crushing capacity of the crusher and an increase in running costs.

[Means for solving the problem] The present invention considers the behavior of particles flowing between rotating blades and the collection mechanism by the rotating blades, and the coarse particles once extracted are collected by the airflow that flows in sequentially. In order to prevent the powder from being mixed into the refined powder without being re-dispersed by It has a configuration that forms a pocket part for dropping it. Thereby, the coarse particles once captured can be reliably returned to the mill grinding section as return powder without being carried into the airflow again.

[Function] Particles flowing at a predetermined speed between the rotating blades of the separator are affected by the inward force caused by the inward airflow, the centrifugal force generated by the rotation of the gas sandwiched between the rotating blades, and the rotating blades. As a result of the combination of the apparent forces in the circumferential direction caused by rotation in opposite rotational directions, a particle of any particle size that has passed through point P in FIG. b3
In other words, fine powder b1 passes through the separator, coarse powder passes b2. After hitting the rotating blade as shown in b3, 6AA body name ζ goes to pocket 1 at the inner diameter end of the rotating blade.
It slides downward or falls freely due to the back-eye type of J-, and is returned to the rotary table.

[Example] Examples will be described below with reference to the drawings.

FIG. 1 is a partially enlarged horizontal cross-sectional view of a rotary separator according to an embodiment of the present invention.

On the other hand, FIGS. 5 to 7 show an example of a conventional rotary separator, in which FIG. 5 is a schematic vertical sectional view, and FIG. Plan view, No. 7
The figure shows a partially enlarged view of FIG.

In Fig. 7, when the rotating blade is rotating counterclockwise at a constant rotation speed (rotational speed V), particles flowing from an arbitrary point P on the arc CD formed by the outer diameter end of the rotating blade are Resistance force due to airflow (inward flow) and centrifugal force (outward force)
Under the influence of the air layer between adjacent rotating blades, the particles move toward the inside of the separator, following an arbitrary trajectory depending on the particle size. In other words, fine powder with a small particle size follows the trajectory a1. Passes between the strokes A-E, and the intermediate powder is A-
Locus a3 between B. The coarse powder draws a trajectory a5 between B-0,
It reaches the inner wall of the rotating blade 15.

However, the particles that have come into contact between B and 0 do not lose their kinetic energy, and are then ejected radially outward along between B and C due to the action of centrifugal force.

On the other hand, among the intermediate particles that have arrived between A and B, the particles that move outward due to centrifugal force move along the BC wall to the outside of the separator in the same way as the particles that abutted between B and C. However, if the inward force due to the airflow balances with the centrifugal force between A and B, or if the inward force exceeds the centrifugal force, the particles will remain between A and B and will be deposited on the wall between A and B. do. These deposited particles are constantly exposed to a steady inward airflow, and when the accumulation has progressed to a certain extent, they are agitated by the inward airflow and peel off from the BC wall, and are mixed into the refined powder side.

Due to the above phenomenon, particles that should normally be classified as coarse particles are mixed in fine particles, resulting in the classification characteristics shown in Figure 8, where the gradient near the classification point is gentle and the classification accuracy (classification (Dosa) gets worse.

In the present invention, the cross-sectional structure of the rotary blade is configured as shown in FIG. 1, and a recess L-15a and a recess H15c are provided on at least one or both edges to capture coarse powder that has reached the rotary blade. By providing a guide path for reliably returning and introducing the material to the crushing section, it is intended to prevent it from being stirred up by steady airflow and being dispersed again.

That is, among the particles starting from point P in Fig. 1, fine powder follows a trajectory b1 toward the refined powder side, and particles with a larger particle size follow a trajectory b2 or b3, etc., after contacting the rotating blade. ,
Pocket) 15a, corner B, blur) 15c, etc. slide down and become returned powder.

FIG. 2 shows another embodiment of the present invention, in which the L-shaped member of the rotating blade 15 has an inclination of 90' or more in the circumferential direction. In this case, compared to the rotating blade shown in Fig. 1, for example, the particles on the trajectory b2 are made easier to move toward the blur (bokeh) 15a, and inevitably fewer particles fall near the corner B, making them more likely to be re-splattered. opportunities will further decrease. Also,
The reason why the bokeh (15c) is provided on the outer diameter side is to reduce the possibility that the coarse powder released into the air from the outer diameter end C of the rotary vane will ride on the airflow again and enter the separator.
The purpose is to prevent re-scattering.

Regarding the consideration of the particle trajectory described above, the incident position of the particle into the separator is set to an arbitrary point P, but when the particle is incident closer to point D than point P shown in Fig. 7 (point P is to the left) When the powder is transferred), the particle size range passing between the EAs becomes wider, and the refined powder becomes coarser. On the other hand, if point P is closer to the right side and closer to 0, the fine powder becomes finer. In reality, since particles are incident between DCs, the overall effect of the above results in the classification characteristics shown in FIG. However, among the particles that have once reached the rotary blade, the ABB particles, which were conventionally mixed into the fine powder by re-scattering, are reliably prevented from being mixed into the fine powder by the present invention, and are not allowed to re-enter the fine powder at the outer diameter end. Since scattering can also be prevented, the classification characteristics change as shown in Figure 9, and the speed of classification is improved.

In Figures 8 and 9, the horizontal axis is the particle diameter, and the vertical axis is the distribution ratio (
Partial classification efficiency) indicates the ratio of the amount of returned powder to large particles for a certain particle size.

The rotating blade of the present invention having the above-described cross-sectional structure has a third
As shown in the schematic bird track diagram shown in the figure, it may be installed (a) vertically, (b) in an inverted shape, or (c) tilted from the vertical direction in a V-shape.

In addition, as a countermeasure against the fluctuation of the classified particle diameter due to the difference in the incident position between the rotary vanes at the separator inlet mentioned above,
It is common to increase the number of blades and reduce the arc length of one pitch of the circumference, but if you cannot or do not want to increase the number of blades more than necessary, use the structure shown in Figure 4. It's okay. That is, in FIG. 4(1), an overhang is provided in the circumferential direction at the outer diameter end to narrow the incident width. However, in this case, if there is a problem that the pressure loss becomes large due to the orifice effect, it is better to try to reduce the pressure loss as in (b) or (C), and in the case of (C),
The combination of perforated pipe and angle is convenient and suitable for manufacturing.

[Effects of the Invention] As described above, according to the present invention, the classification accuracy of the rotary separator is improved, the mixing of coarse powder into refined powder is suppressed to the utmost, and a product with a sharply classified particle size structure can be obtained. This improves the quality of the product, and since the coarse powder after classification by the separator is quickly returned to the crushing section of the crusher, crushing capacity increases and running costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a partially enlarged horizontal cross-sectional view of a rotating blade showing one embodiment of the present invention, and FIGS. 2 and 4 are partially enlarged horizontal cross-sectional views of a rotating blade showing other embodiments of the present invention. Figure, 3rd
The figure is a schematic diagram of an embodiment of the present invention, FIGS. 5 to 7 are related to a conventional embodiment, and FIG. 5 is a schematic vertical sectional view.
6 is a sectional view taken along the line V-V in FIG. 5, and FIG. 7 is a partially enlarged view of FIG. 6. FIGS. 8 and 9 are diagrams showing classification characteristics of fine powder in the conventional method and in the present invention. 3... Rotating table, 4... Grinding roller, 13
...Separator rotor, 15...Separator rotating blade, 15a, 15c...Pocket portion, 16...Discharge pipe, al, a2, a3, a4,
a5. bl, b2, b3...particle trajectory, P...particle incident position. Patent applicant: Ube Industries, Ltd. Figure 1 Figure 2 @ 3v! J (a) (b) (c) Fig. 4 (a) (b) Busy) Fig. 5 Fig. 6 vgl

Claims (1)

[Claims] In a separator of a vertical crusher in which a rotating shaft is provided in the classification part, and a rotating blade in which a plurality of plate-shaped blades are radially attached to the rotating shaft is fixed, the horizontal cross-sectional shape of the rotating blade is approximately L-shaped; A rotary separator for a vertical pulverizer, characterized in that a pocket is provided on at least one edge of the rotary separator for sliding powder and granules downward.