JPH0349619B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to an airflow guide device for a roller mill.

(Prior Art) Conventionally, there have been roller mills for pulverizing objects to be pulverized, and some of these roller mills have a structure as shown in FIG. 5, for example.

To explain this with a diagram, 1 is a roller mill;
Reference numeral 3 denotes a pedestal, and a casing 4 is supported on this pedestal 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 located at the lower part of the casing 4 . 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 crushing table 5 is a crushing chamber 8, in which the material to be crushed on the crushing table 5 is crushed by applying pressure.
~4 grinding rollers 10 are provided. These crushing rollers 10 are supported on the pedestal 3 side.

The outer peripheral surface of the crushing table 5 and the casing 4
A nozzle 11 is formed between the inner peripheral surface of the lower part 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 provided in the casing 4 corresponding to the discharge port 12, and the classifier 13 rotates coaxially with the crushing table 5 around its axis. In addition, this classifier 1
The bottom side of 3 is an inverted truncated conical cone 15
It is covered with 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 upper surface of the crushing table 5 and the crushing roller 10. The thus pulverized powder is then passed through the nozzle 11.
It is blown upward by the airflow from the At this time, the flow velocity of the mixed flow of air and powder weakens as it moves upward, so this powder flows into the classifier 1.
By the time the grain reaches 3, it is first classified into coarse grains and fine grains according to their weight ratio. 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 are fed into 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. Then, 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 on the crushing table 5 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 coarse particles are mixed with fine particles. The grains may be sent to the classifier 13, and in this case, there is an inconvenience that the classification efficiency of the secondary classification in the classifier 13 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, and this guide surface once reverses the air flow toward the crushing table 5. It has been proposed that this improves the classification efficiency of primary classification (for example, Japanese Patent Application Laid-Open No. 1986-
244353).

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

(Purpose 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 improve the classification efficiency of

(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. Provide the parts,
The guide member is located above the crushing roller, and a groove is formed on the upper surface of the guide member, extending in the direction in which the guide member projects.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. 1 and FIG. 2. The basic configuration of this embodiment 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.

In the figure, reference numeral 17 indicates the crushing table 5
It is a supply chute that supplies the top of the casing 4.
It is installed through the inside and outside of the.

A guide member 18 is provided in the middle of the upper and lower parts of the casing 4 to reverse the airflow ejected from the nozzle 11 and rising downward toward the crushing table 5. Three guide members 18 are provided at equal intervals in the circumferential direction of the casing 4, and each guide member 18 protrudes from the inside of the casing 4 to a position directly below the classifier 13, and tilts downward as it advances toward its protruding end. ing.

Each of the guide members 18 also includes a trapezoidal guide plate 19 whose width becomes smaller toward its protruding end in plan view, and a pair of auxiliary guide plates 20, 20 supported on both sides of this guide plate 19. It consists of These guide plates 19 and auxiliary guide plates 2
0, the guide member 18 has an H-shaped cross section, and grooves 21 and 22 on the upper and lower surfaces thereof each extend toward the protruding end of the guide member 18. In the above case, the inclination angle θ of the guide plate 19 with respect to the horizontal line is
It is 60°.

According to this configuration, the guide member has an H-shaped cross section, and has sufficient strength compared to a simple flat plate. Further, a part of the air flow ejected from the nozzle 11 is once guided by the groove 22 on the lower side of the guide member 18, turned downward and reversed, and is directed onto the crushing table 5. Therefore, the coarse particles contained in the powder crushed on the crushing table 5 can be effectively dropped onto the crushing table 5, and the classification efficiency of the primary classification can be further improved.

Moreover, the groove 21 on the upper side of this guide member 18 is filled with coarse particles that are classified by the classifier 13 and descend (arrow D in the figure).
is received and guided onto a crushing table 5 without being affected by the air flow rising from a nozzle 11, and is crushed.

In addition, the roller mill 1 shown in the above embodiment is as follows:
Although it does not have the cone 15 or guide vane 16 shown in the conventional example, these cones 15 are included in the above example.
Alternatively, a guide vane 16 may be added.

(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 that is ejected from the nozzle and rises. is once guided by a guide member, turned downward, and faces onto the crushing table. In this case, since the protruding end of the guide member extends directly below the classifier, the airflow rising from the nozzle is prevented from going directly to the classifier, and this airflow is more reliably directed to the crushing table. be guided towards it. Therefore, the coarse particles contained in the powder crushed on the crushing table are effectively dropped onto the crushing table,
An improvement in the classification efficiency of the primary classification is achieved.

In addition, since the guide member is located above the crushing roller, conventionally the guide member was at almost the same height as the crushing roller and close to the nozzle outlet, so the force from this nozzle was Compared to the case where the guide member of the present invention was worn out due to receiving good jet air, the above-mentioned guide member of the present invention is prevented from being worn out.

In other words, wear of the guide member is suppressed and primary classification is performed satisfactorily.

In addition, since a groove is formed on the upper surface of the guide member and extends in the direction in which the guide member protrudes, this groove receives the coarse particles that have been classified by the classifier and descend.
This is guided onto a crushing table and crushed without being affected by the air flow rising from the nozzle. Therefore, coarse particles are prevented from jumping into the classifier unnecessarily, and this secondary classification is also performed satisfactorily.

In other words, since both the primary and secondary classification are performed well as described above, coarse particles are effectively crushed, improving the classification efficiency and producing products with high quality in terms of particle size. Become.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a plan sectional view of a roller mill, FIG. 2 is a cross-sectional view taken along the line - - of FIG. 1, and FIG. 3 is a roller mill showing a conventional example. FIG. 1...Roller mill, 4...Casing, 5...
Grinding table, 8... Grinding chamber,... Nozzle, 12
...Discharge port, 13... Classifier, 18... Guide member, 19... Guide plate, 20... Auxiliary guide plate, 21
……groove.

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 about a vertical axis, and a crushing roller is provided above the crushing table, and the outer peripheral surface of the same crushing table and the crushing roller are provided above the crushing table. A nozzle is provided between the inner surface of the casing facing the outer circumferential surface to introduce an air flow into the grinding chamber, and the crushed or powdered material is transported between the top surface of the grinding table and the grinding roller with the air flow. In a roller mill in which a discharge port is formed in the upper part of the casing and a classifier is provided in the casing corresponding to the discharge port, the roller mill protrudes from the inner surface of the casing to a position directly below the classifier, and the projecting end side A guide member for the air flow that tilts downward as it advances is provided, the guide member is positioned above the crushing roller, and a groove is formed on the upper surface of the guide member that extends in the direction in which the air flow protrudes. Airflow guide device for roller mills.