JPH067829Y2 - Air classifier - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an air classifier equipped with rotary blades, which is incorporated in a crushing device such as a vertical mill for crushing cement clinker, slag and the like.

[Conventional technology]

An example of a conventional air classifier will be described with reference to FIGS. 3 and 4. Fig. 3 is an overall longitudinal sectional view, and Fig. 4 is IV- in Fig. 3.
It is an IV sectional view.

In the figure, (1) is a classification chamber, (2) is the outer wall of the classification chamber (1), (3) is a motor with a speed reducer, (4) is a drive shaft driven by the motor (3), (5 ) Is a disc fixed to the lower end of the drive shaft (4). (6) is a fixed ring (8) at the tip of the same disk (5) and support rod (7)
A plurality of classification blades disposed between and, each classification blade (6) being directed in the radial direction as shown in FIG. 4, and having an axis line along the generatrix of a vertical cylinder. They are mounted at predetermined intervals in the circumferential direction. Further, an inlet (9a) for the dust-containing gas and an exhaust pipe (9b) are provided.

Explaining the operation of such an air classifier, a powder having a wide particle size distribution crushed by a crusher (not shown) is used as dust gas together with the attractant gas from the inlet (9a) to the classification chamber. It is introduced in (1). The dust-containing gas becomes an ascending flow (a) in the classification chamber (1) and is rotated by the motor (3) via the drive shaft (4), disc (5), fixed ring (7), etc. Reach the air passage between the classification blades (6). Here, relatively large particles collide with the classification blade (6) with a large inertial force and are blown to the outer wall (2) of the classification chamber (1), colliding and falling along the outer wall (2) by the action of gravity. , It goes out of the classifier through the inlet (9a) and is collected. Also, relatively small particles can be
Since the repulsive force (centrifugal force) due to the collision with (6) is small, it is entrained in the attracted gas as it is, passes through the discharge pipe (9b), goes out of the classifier, and is collected by a dust collector (not shown). In this way, the powder is separated into fine powder and coarse particles.

[Problems to be solved by the device]

In the above-mentioned conventional air classifier, the dust-containing gas in the classifying chamber (1) hits the ceiling part (2a) of the outer wall (2), and a large amount of gas is easily introduced into the upper part of the classifying blade (6) by its force. . Therefore, since the classification load of the classification blade is biased upward, there is a problem to be solved that the fine powder (product) taken out together with the air flow cannot meet the demand for adjusting the particle size and the particle size distribution width.

[Means for Solving the Problems]

As a means for solving the above-mentioned problems, the present invention uses a plurality of classification blades whose axes are arranged along the generatrix of a vertical cylinder and rotates around coaxial lines so that fine powder and coarse particles can be conveyed along with an updraft. In the case of separating into, and a cylindrical inner cylinder which is arranged inwardly at the upper part of the classification blade,
The present invention proposes an air classifier characterized by including an inner cylinder fixing ring that closes between the upper end of the classification blade and the upper end of the inner cylinder.

[Action]

In the present invention, the attractant gas flowing from the outer circumference to the classifying blade is blocked by the inner cylinder fixing ring between the upper end of the classifying blade and the upper end of the inner cylinder. Since the gas flows, the resistance of the gas flowing into the upper part of the classifying blade becomes large, and the vertical distribution of the inflow amount of the dust-containing gas becomes uniform.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 is an overall vertical sectional view, and FIG. 2 is a II-II sectional view of FIG. The same parts as those of the conventional one described with reference to FIGS. 3 and 4 are designated by the same reference numerals and detailed description thereof will be omitted.

In this embodiment, a cylindrical inner cylinder (11) is arranged inside the upper part of the classification blade (6) with a gap, and the inner cylinder fixing ring (1
Suspended from 2). This inner tube fixing ring (12)
It is supported by a fixing ring (8) that supports the upper end of the classification blade (6) and closes the upper end of the classification blade (6) and the upper end of the inner cylinder (11) together with the fixing ring (8).

This embodiment is configured as described above, the dust-containing gas rising in the classification chamber (1) hits the ceiling (2a) of the outer wall of the classification chamber and changes its direction at a right angle, and the classification blade (6) Although it tends to flow into the upper part a lot, the gas flowing into the upper part of the classifying blade is
Along the outer wall of (11), once descend to the lower end of the inner cylinder,
Take a path with a large flow resistance that flows inward. Therefore, since the flow resistance is higher at the upper part of the classification blade (6) where the dust-containing gas is likely to flow in, the distribution of the inflow gas amount in the vertical direction of the classification blade (6) is made uniform and the desired particles are obtained. A product fine having a diameter and a particle size distribution width is obtained.

It was confirmed by experiments that the rotation power of the classification blade can be reduced by installing the inner cylinder. Fig. 5 shows classification blade (6)
The relationship between the height of the inner cylinder (11) (distance from the upper end of the classifying blade) to the height of the inner cylinder (11) and the ratio of rotational power to the case without the inner cylinder (11) is shown. Therefore, when the ratio of the height of the inner cylinder to the height of the classification blade is about 1/2, the rotational power becomes the minimum. Considering this and the effect of equalizing the inflow gas amount described above, the height of the inner cylinder (11) is preferably about 1/4 to 3/4 of the height of the classification blade (6), and this It is preferable that the inner cylinder height can be adjusted by an external operation.

[Effect of device]

According to the present invention, since the amount of the dust-containing gas flowing into the classifying blade becomes uniform in the vertical direction, product fine particles having a desired particle size and particle size distribution width can be obtained, and the rotational power of the classifying blade can be reduced. That is an excellent effect.

[Brief description of drawings]

FIG. 1 is an overall longitudinal sectional view of an embodiment of the present invention, FIG. 2 is an II-II sectional view of FIG. 1, and FIG. 3 is an overall longitudinal sectional view of an example of a conventional air classifier. Is the IV-IV sectional view of FIG.
The figure is a diagram showing the relationship between the rotational power of the classification blade and the inner cylinder size. (1) …… Classification chamber; (2) …… Outer wall; (3) …… Motor; (4) …… Drive shaft; (5) …… Disc; (6) …… Classification blades; (7)… … Support rod; (8) …… Fixing ring; (9a) …… Inlet port; (9b) …… Discharge pipe; (11) …… Inner cylinder; (12) …… Inner cylinder fixing ring.

Front page continuation (72) Inventor Katsuhisa Tanaka, 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Yoshio Sugimoto 4-22, Kannon Shinmachi, Nishi-ku, Hiroshima Prefecture Issue Mitsubishi Heavy Industries, Ltd. Hiroshima Works (56) Reference JP 62-191082 (JP, A) JP 60-110346 (JP, A) Actually opened 63-9277 (JP, U) Actually opened 62 -151987 (JP, U) Actually open 64-44087 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A device for separating powder carried along with an updraft into fine powder and coarse particles by a plurality of classifying blades whose axis is arranged along a generatrix of a vertical cylinder and which rotates around a coaxial line. , A cylindrical inner cylinder arranged at a distance inward from the upper part of the classification blade, and an inner cylinder fixing ring that closes between the upper end of the classification blade and the upper end of the inner cylinder. A characteristic air classifier.