JPS6342746A - Air stream guide apparatus of roller mill - Google Patents

Abstract

(57) [Abstract] 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 an airflow guide device for a roller mill.

(Prior art) Conventionally, roller mills have been used to finely grind objects to be ground.
Some roller mills are constructed as shown in FIG. 5, for example.

To explain this with a diagram, l is a roller mill, 3 is a stand thereof, and a casing 4 is supported on this stand 3. Further, a crushing table 5 is supported on the pedestal 3 so as to be rotatable about a vertical axis, and this crushing table 5 is attached to the casing 4.
It is located at the bottom of the interior. This crushing table 5 is rotationally driven by an electric motor 7 (indicated by an arrow R in the figure). A space surrounded by the inner surface of the casing 4 and the upper surface of the grinding table 5 is a grinding chamber 8, in which two to four grinding rollers 10 are provided to pressurize and grind the material on the grinding table 5. . These crushing rollers 10 are
Support on the side.

A nozzle 11 is formed between the outer circumferential surface of the grinding table 5 and the lower inner circumferential surface of the casing 4, and an air flow is ejected from the nozzle 11 toward the inside of the casing 4. Arrow A in the figure). Meanwhile, an air outlet 12 is formed in the upper part of the casing 4 . A rotary classifier 13 is installed in the casing 4 corresponding to this discharge port 12.
The classifier 13 is coaxial with the crushing table 5 and rotates about its axis. Further, the lower surface side of the classifier 13 is covered with an inverted truncated conical cone 15. A plurality of guide vanes 16 are provided between the upper edge of the cone 15 and the ceiling surface of the casing 4 at equal intervals in the circumferential direction. The material to be crushed is supplied to approximately the center of the crushing table 5 by a supply chute (not shown).

When the crushing table 5 is rotated, the object to be crushed is crushed between the north surface of the crushing table 5 and the crushing roller 10. The thus pulverized powder is blown upward by the airflow from the nozzle 11. At this time, the flow velocity of this mixed flow of air and powder becomes weaker as it moves upward, so that by the time it reaches the classifier 13, this powder is classified into -order by weight ratio and divided into coarse particles and fine particles. It will be done. Then, the coarse particles separate from the upward flow and fall onto the crushing table 5, where they are crushed again (arrow B in the figure). On the other hand, the fine particles pass through the guide vane 16 while rotating around the cone 15, and pass through the classifier 13.
(arrow C in the figure). By the way, since these fine particles still contain coarse particles, the classifier 13 performs secondary classification of this powder and separates it into coarse particles and fine particles. The coarse particles at this time pass through the cone 15 and fall onto the crushing table 5 again to be crushed (arrow D in the figure), and the fine particles are discharged to the outside of the crushing chamber 8 through the discharge port 12 ( This is the product as shown by arrow E in the figure.

By the way, in the above configuration, the powder crushed by the crushing table 5-L is blown up by the air flow ejected from the nozzle 11 and is primarily classified before reaching the classifier 13, but in this case, a relatively large amount of fine particles and Coarse particles may be sent to the classifier 13, and in this case, the classifier 1
This results in a disadvantage that the classification efficiency of the secondary classification in step 3 is reduced.

Therefore, in order to deal with this problem, an arc-shaped guide surface is formed on the inner surface of the casing 4 on the exit side of the nozzle 11,
It has been proposed that this guide surface once reverses the air flow toward the crushing table 5, thereby improving the classification efficiency of -order classification (for example,
(Japanese Patent Application Laid-open No. 60-244353).

(Problem to be Solved by the Invention) However, in the above case, in order to improve the classification efficiency of -order classification, it is necessary to form a guide surface near the nozzle 11. The speed of the air flow passing through the guide surface is high, which causes the disadvantage that the guide surface is prematurely worn out by the particles moving with the air flow.

(Objective of the Invention) This invention was made in view of the above-mentioned circumstances, and aims to suppress wear and perform primary classification with good classification efficiency, thereby improving secondary classification in a classifier. The purpose is to increase classification efficiency.

(Structure of the Invention) A feature of the present invention for achieving the above object is that the airflow is guided from the inner surface of the casing of the roller mill to a position directly below the classifier, and that tilts downward as it advances toward the protruding end. The point is that the members are provided.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 4. The basic configuration of each of these embodiments is almost the same as that of the prior art described above. Therefore, the same components are given the same reference numerals and their explanations will be omitted.

1 and 2 show a first embodiment.

In the figure, reference numeral 17 denotes a supply chute for supplying the material to be crushed onto the crushing table 5, and is provided to penetrate the inside and outside of the casing 4.

The casing 4 is provided with a guide plate 19, which is a guide member, in the middle of the upper and lower parts of the casing 4 and reverses the air flow ejected from the nozzle 11 and rising downward toward the crushing table 5. Four guide plates 19 are provided at equal intervals in the direction of the casing 4, and each guide plate 19 is connected to the classifier 13 from the inner surface of the pedestal 3.
It protrudes to a position directly below the , and slopes downward toward the protruding end. Further, this guide plate 19 has a trapezoidal shape whose width decreases toward its protruding end. In the above case, the inclination angle θ of the guide plate 19 with respect to the horizontal line is 30
°.

According to the above configuration, a part of the air flow ejected from the nozzle 11 is once guided by the guide plate 19, reversed downward, and directed onto the grinding table S. Therefore,
Coarse particles occupying a part of the powder crushed on the crushing table 5 can be effectively dropped onto the crushing table 5.

3 and 4 show a second embodiment.

In the figure, the guide member has an H-shaped cross section, and the guide member has an H-shaped cross section.
It is composed of a guide plate 19 in the embodiment and auxiliary guide plates 20 and 20 supported on both sides of this guide plate 19.

According to this configuration, the guide member has an H-shaped cross section and can maintain sufficient strength. Further, since the lower surface of this guide member has a groove shape that forcibly guides the air flow so as to reverse it downward, the classification efficiency of the -order classification can be further improved.

In addition, since the upper surface of this guide member is also groove-shaped,
The coarse particles classified by the classifier 13 and falling (arrow D in the figure) are received and guided onto the crushing table S without being affected by the air flow from the nozzle 11. In the above case,
The inclination angle 0 of the guide member is 80°.

Although the roller mill 1 shown in each of the above embodiments does not have the cone 15 and guide vane 16 shown in the conventional example, the cone 15 and guide vane 16 may be added to the above embodiments.

(Effects of the Invention) According to the present invention, since the air flow guide member is provided that protrudes from the inner surface of the casing of the roller mill and tilts downward as it advances toward the protruding end, the air flow is ejected from the nozzle and rises. The airflow is once guided by the guide member, reversed downward, and directed onto the grinding table. In this case, since the protruding end of the guide member extends directly below the classifier, the airflow is prevented from going directly to the classifier, and this airflow is more reliably guided toward the crushing table. Ru. Therefore, the coarse particles occupying a part of the powder crushed on the crushing table can be effectively dropped onto the crushing table, and the classification efficiency of -order classification can be improved. In addition, as much as the classification efficiency has improved in this way,
The amount of coarse particles reaching the classifier is reduced, and the classification efficiency of the secondary classification in the classifier is improved. As a result, the grinding efficiency is improved and a product of high quality in terms of particle size is obtained.

Further, as described above, since the guide member effectively guides the coarse particles blown up by the airflow from the nozzle onto the grinding table, it is not necessary to place the guide member close to the nozzle. Therefore, wear of the guide surface can be suppressed compared to conventional methods in which the guide surface is formed close to the outlet of the nozzle.

[Brief explanation of drawings]

1 to 4 show embodiments of the present invention, and FIGS. 1 and 2 show the first embodiment. FIG. 1 is a plan cross-sectional view of a low 3 mill, and FIG. 3 and 4 are the second embodiment; FIG. 53 is a plan sectional view of the roller mill; FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3; $
FIG. 5 is a longitudinal sectional view of a conventional roller mill. No. 10 roller mill, 4 * Red casing, 5φ・Crushing table, 8φφ crushing chamber,・Koma nozzle 12◆・Discharge port, 13・・Classifier, 19・・Guide plate (guide member), 20
...Auxiliary guide board (guide member).

Claims (1)

[Claims] 1. A casing forming a crushing chamber for the material to be crushed is provided, a crushing table is provided in the lower part of the casing so as to be rotatable around a vertical axis, and the outer circumferential surface of the crushing table and the inner surface of the casing facing the outer circumferential surface are A nozzle is provided between the casing and the casing to guide an air flow into the grinding chamber, and a discharge port is formed in the upper part of the casing to discharge the powder and granules crushed on the grinding table along with the air flow, and corresponds to the discharge port. A roller mill in which a classifier is provided inside a casing is provided with an airflow guide member that projects from the inner surface of the casing to a position directly below the classifier and that tilts downward as it advances toward the projecting end side. Roller mill airflow guide device.