JPH0454867Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a powder and granule classification device that improves the classification efficiency of powder and granules.

(Prior Art) Some of the above-mentioned powder and granule classification apparatuses are installed in roller mills, and this is configured as shown in FIG. 4, for example.

In the figure, 1 is a classification device for powder M.
This classification device 1 is provided on the upper part of the roller mill,
The crushed powder M is classified into coarse powder L and fine powder S. Then, this classified coarse powder L descends to the crushing chamber 2 of the roller mill and is re-pulverized, while the fine powder S
is discharged outside the roller mill.

The casing 4 of the upper classifier 1 has its axis vertically oriented, and has a truncated conical cylinder member 5, a ceiling plate 6 that closes the upper end of the truncated conical cylinder member 5, and a lower end of the truncated conical cylinder member 5. Inverted truncated conical cylinder member 7 extending downward
The crushing chamber 2 is connected below the inverted truncated conical cylinder member 7.

A plurality of fixed blades 11 are fixed in the casing 4 in the circumferential direction coaxially with the casing 4,
An inverted truncated cone-shaped cone 12 is provided at the lower end of the fixed blade 11 and extends downward from the lower end.

Further, the fixed blade 11 is attached to the casing 4.
A rotating shaft 14 is supported substantially coaxially with the group. The rotating shaft 14 supports two upper and lower supporting plates 15 and 16 vertically within the casing 4, and a plurality of supporting plates 15 and 16 are provided between the supporting plates 15 and 16 in the circumferential direction around the axis of the rotating shaft 14. The classification blade 18 is supported. Further, each classification blade 1 is provided on the upper support plate 15.
A ventilation hole 20 is formed at a position radially inward from the eighth group.

Discharge hole 2 that communicates the inside and outside of the casing 4
1 is formed on the ceiling plate 6. This discharge hole 21
corresponds to the center of rotation of the group of classification blades 18. 24 is an electric motor, and 25 is a reduction gear.

Then, when the electric motor 24 rotates the group of classification blades 18 via the speed reducer 25 (as shown by the arrow R in the figure), the granular material M rising with the air flow G is classified by the group of classification blades 18. That is, the coarse powder L that has passed between the fixed blades 11 toward the classification blade 18 is subjected to a large centrifugal force by the classification blade 18 here. Therefore, the cone cannot pass through the classification blade 18, and therefore passes through the inside of the cone 12 and is lowered into the crushing chamber 2.
will be shattered again. On the other hand, for fine powder S, the classification blade 18
Since the centrifugal force applied from the
It flows into the inside of the group, further passes through the discharge hole 21 and is discharged to the outside of the casing 4.

(Problem to be solved by the invention) By the way, since the group of classification blades 18 rotates relative to the ceiling plate 6, a gap is formed between the ceiling plate 6 and the upper support plate 15. There is.
However, this void causes the following inconvenience.
That is, when the granular material M is classified by the group of classification blades 18, a part of the granular material M does not pass between the classification blades 18, but passes through the voids along with the airflow G,
It may be directly discharged from the discharge hole 21 (indicated by arrow A in the figure). In this case, since a part of the granular material M contains coarse powder L, this causes a reduction in the classification efficiency of the classifier 1.

As an example, talc crushed in the crushing chamber 2 of the roller mill is classified by the classifier 1, and the discharge hole 21
The fine powder S discharged from the air stream G was collected by a bag filter or the like. The collected talc fine powder S has 0.1% residue after passing through 325 mesh (44μ).
This results in the inconvenience that fine powder products such as talc, which require high quality, cannot meet the requirements.

(Purpose of the invention) This invention was made with attention to the above-mentioned circumstances, and a part of the powder and granules pass through the gap between the ceiling plate and the upper end of the classification blade and are not classified. The purpose is to prevent the particles from being discharged and thereby improve the classification efficiency of the powder/granular material classification device.

(Structure of the device) The feature of this device for achieving the above object is that a plurality of blades rotate together with the classification blade group and extend radially outward in a direction opposite to the rotational direction of the classification blade group. A rotating blade is provided between the ceiling plate and the upper end of the group of classification blades, and a labyrinth is formed between the same ceiling plate and the upper end of the classification blade radially inward of the casing from each of these rotating blades. It is in.

(Example) Hereinafter, an example of this invention will be described with reference to FIGS. 1 to 3.

Note that the basic configuration and operation of this embodiment are the same as those of the conventional configuration. Therefore, the common configurations will simply be designated by their reference numerals in the drawings and their explanations will be omitted, and only the different configurations will be explained.

In the figure, the upper end of each fixed blade 11 is connected to the ceiling plate 6.
The fixed vane 11 and the cone 12 are supported by the casing 4. Further, as shown in FIG. 3, each of the fixed blades 11 is arranged at equal intervals in the circumferential direction around the axis of the casing 4, and each of the fixed blades 11 has a cross-sectional shape that changes in diameter as it progresses in the rotational direction R of the classification blade 18. extending inward. On the other hand, the classification blades 18 are also arranged at equal intervals in the circumferential direction around the axis of the casing 4, and their cross-sectional shape extends in the radial direction.

Then, the granular material M raised by the airflow G passes between the fixed blades 11 toward the group of classification blades 18, and centrifugal force is applied by the group of rotating classification blades 18. The action at this time is the same as in the conventional example described above, and the coarse powder L does not pass between the classification blades 18, while the fine powder S passes between the classification blades 18 together with the airflow G.

A cylindrical member 30 protrudes from the lower surface of the ceiling plate 6 and covers the gap between the ceiling plate 6 and the upper support plate 15 from the outside in the radial direction.

Further, as shown in FIG. 3, the upper support plate 1
A plurality of rotating blades 32 are protruded from the top surface of the classification blade 5 at equal intervals in the circumferential direction around the axis of the classification blade 18 group. The cross-sectional shape of each rotating blade 32 extends radially outward in the direction opposite to the rotation direction R of the group of classification blades 18. For this reason, the ceiling board 6
The powder M that is about to flow into the group of classification blades 18 through the gap between the upper support plate 15 and the upper support plate 15 is pushed back radially outward by the rotating rotary blades 32. Therefore, almost all of the powder M passes between the classification blades 18 and is classified there.

Further, a labyrinth 34 is formed between the ceiling plate 6 and the upper support plate 15 on the radially inner side of the casing 4 than the rotating blade 32 . That is, as shown in FIGS. 1 and 3, a first cylindrical body 35 extending toward the lower surface of the ceiling plate 6 is provided on the upper surface of the upper support plate 15 on the radially inward side. . on the other hand,
On the lower surface of the ceiling plate 6, a pair of large and small second cylindrical bodies 3 sandwiching the upper part of the first cylindrical body 35 from the inside and outside in the radial direction are provided.
6 and 36 are provided protrudingly. For this reason, as shown in FIG.
The gap between 6 and 6 has a bent shape,
A labyrinth 34 is formed here.

As an example, when talc is crushed by a roller mill, classified by the classifier 1 having the above configuration, and the fine powder S discharged to the outside from the discharge hole 21 is investigated,
The collected talc fine powder S had a residue of 0.1% or less after passing through a 325 mesh (44μ). As a result, the quality of talc as a fine powder product has improved compared to conventional products in which the residue exceeded 0.1%.

Note that the number, shape, and mounting angle of the rotary blades 32, the shape of the labyrinth 34, etc. are not limited to the example illustrated above, and may vary depending on the type of powder or granular material M,
It may be determined based on particle size, etc.

(Effect of the invention) According to this invention, the classification blades rotate together with the group of classification blades,
Since a plurality of rotating blades that extend radially outward in the opposite direction to the rotational direction of the classification blade group are provided between the ceiling plate and the upper end of the classification blade group, some of the powder and granules are transferred to the classification blade. Even if you try to pass through the gap between the ceiling plate and the top of the classification blade group without passing through the
This granular material is pushed back radially outward by the rotating blade group, and is prevented from passing through the gap. In addition, since a labyrinth is formed between the above ceiling plate and the upper end of the classification blade group, it is more certain that part of the powder particles will not attempt to pass through the gap between the above ceiling plate and the upper end of the classification blade group. Prevented.

Therefore, almost all of the powder supplied into the casing passes between the classification blades and is classified there. As a result, the classification efficiency of the classification device is improved.

Furthermore, since the labyrinth is arranged in parallel with the rotating blade group, the labyrinth suppresses the generation of airflow due to the rotation of the rotating blade group. Therefore, first, the rotating blades are prevented from interfering with the classification of the powder or granular material by the classification blade group. Second, it also prevents the occurrence of the inconvenience that the fine powder that has been classified by the classification blade group and has flowed into the classification blade group passes through the rotary blade group and flows out again to the outside due to the airflow caused by the rotation of the rotary blade group. Ru.

Therefore, by providing the rotary blade and the labyrinth in the classification device, the efficiency of classifying powder and granules can be effectively improved.

[Brief explanation of the drawing]

Figures 1 to 3 show examples of this invention,
Fig. 1 is a partially enlarged view of Fig. 2, Fig. 2 is a longitudinal cross-sectional view of the classification device, Fig. 3 is a cross-sectional view taken along the - line in Fig. 1, Fig. 4 shows a conventional example, and Fig. 2 is a longitudinal cross-sectional view of the classification device. This is a diagram corresponding to . 1... Classifier, 4... Casing, 6... Ceiling plate, 32... Rotating blade, 34... Labyrinth,
M...Powder, G...Airflow, S...Fine powder, L...
Coarse powder.

Claims (1)

[Scope of utility model registration request] A casing with a circular cross section whose axis is vertically oriented and whose upper end is closed by a ceiling plate is provided, and a plurality of classification blades are provided in the circumferential direction coaxially with the casing and rotate around its axis, and the rotation center of the group of classification blades is A powder and granular material classification device in which a discharge hole is formed in the ceiling plate in accordance with the above, and the powder and granular material supplied into the casing is made to pass between classification blades together with an air flow and discharged from the discharge hole to the outside of the casing. , a plurality of rotary blades are provided between the ceiling plate and the upper end of the classification blade group, rotating together with the classification blade group and extending radially outward in a direction opposite to the rotational direction of the classification blade group, A powder and granular material classification device characterized in that a labyrinth is formed between the ceiling plate and the upper end of the classification blade at a position radially inward of the casing from each of these rotating blades.