JPH05277389A - Vertical roller mill - Google Patents

Abstract

PURPOSE:To increase the classification performance of a classification means and the grinding performance of a grinding part by classifying the ground material supplied from the grinding part by the classification means, discharging the classified coarse grains from a classification chamber by a carrier means, effectively preventing that the coarse grains are reflown into the classification chamber and circulation flow is formed and reducing the concentration of the grains of the ground material in the classification chamber. CONSTITUTION:A classification chamber 39 is formed of a internal cylinder 40 in a casing 18. A classification means 16 is provided in the classification chamber 39. Ground material supplied from a grinding part 38 is classified into coarse grains (d) and particualtes (c). A second carrier means 24 for carrying the coarse grains (d) classified by the classification means 16 is connected to a coarse grain port 41 opened in the lower end of the internal. cylinder 40 and provided in the casing 18. Further, a first carrier means 20 is provided in the lower part of the second carrier means 21, and carries a mixture 36 consisting of feed 30 to pulverizing machine and the coarse grains (d) supplied from the carrier means 24. to a grinding part 38. The concentration of grains of the ground material in the classification chamber 39 is reduced. A ground product 56 consisting of particulates classified by the classification means 16 is obtained from a discharge port 52.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved vertical roller mill for obtaining crushed products consisting of ultrafine particles.

[0002]

2. Description of the Related Art Conventionally, as a vertical roller mill having a crushing section which contains a classifying means in a casing and which comprises a roller and a table, an independent classifying machine is added to the outside of the casing, and the crushing section is used in the classifying means. It is known that the pulverized product of No. 1 is classified into coarse particles and fine particles, and the coarse particles are further classified by a classifier to recover fine particles contained in the coarse particles (JP-A-57-167746). Gazette)

In this type of vertical roller mill, since coarse particles returned to the crushing section without sufficient classification by the classifying means contain a large amount of fine powder, the coarse particles are further guided to a classifier. The particles are classified and the fine particles contained in the coarse particles are collected as a crushed product.

[0004]

However, in the above-mentioned conventional structure, it is effective in that the fine particles contained in the coarse particles are recovered as a crushed product by the classifier from the coarse particles classified by the classifying means. Since an independent classifier is added to the outside of the casing in addition to the classifying means accommodated in the above, the structure and operation adjustment of the vertical roller mill may be complicated, which is not preferable.

The present invention has been made to solve the above problems, and an object thereof is to discharge coarse particles classified by a classifying unit from a classifying unit by a conveying unit and re-fly into the classifying chamber. To effectively prevent the formation of a circulating flow and reduce the particle concentration of the pulverized material in the classification chamber to improve the classification performance of the classification means and the pulverization performance of the crushing section to obtain a crushed product consisting of classified ultrafine particles. And to provide an improved vertical roller mill capable of avoiding the addition of an independent classifier.

[0006]

In order to achieve the above object, the present invention is a vertical roller mill having a crushing section which is provided with a classifying means in a casing and which comprises a roller and a table, wherein the classifying means is in the casing. A second conveying means provided in the classified chamber formed by the inner cylinder for classifying the crushed material from the crushing unit into coarse particles and fine particles, and conveying the coarse particles classified by the classifying means. Is connected to the coarse grain opening opened at the lower end of the inner cylinder and is disposed in the casing,
The first transfer means for transferring the mixture of the crushed material and the coarse particles from the second transfer means to the crushing section is arranged below the second transfer means to reduce the particle concentration of the crushed material in the classification chamber. It is characterized in that a crushed product consisting of fine particles classified by a classification means is obtained from an outlet.

[0007]

In this way, when the vertical roller mill is operated, the mixture of the crushed material and the coarse particles classified from the second conveying means is supplied to the crushing section by the first conveying means and the air flow is generated in the crushing section. In order to obtain a crushed product consisting of fine particles from the outlet, it is crushed under the introduction of become. On the other hand, coarse particles are discharged from the coarse particle port at the lower end of the inner cylinder by the second conveying means and are supplied to the first conveying means through the airtight supply valve of the connection passage to form a continuous coarse particle path.

In the coarse particle path, the pressure of the air flow in the crushing section is substantially shut off by the airtight supply valve, so that the air flow is accompanied by the air flow without being acted upon in the classifying chamber, and re-flying in the classifying chamber for circulation. It is possible to effectively prevent the formation of crushed particles, reduce the particle concentration of the crushed material in the classification chamber, and improve the classification performance of the classification means and the crushing performance of the crushing section to obtain a crushed product composed of classified ultrafine particles. .. Moreover,
Of course, it is possible to avoid adding an independent classifier.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a vertical roller mill showing an embodiment of the present invention. In FIG. 1, a vertical roller mill 10 has a table 14 below which is rotated by a drive device (not shown), and a plurality of rollers 12 are provided on the upper portion of the table 14. 38 is formed.

The roller 12 pressurizes the material layer formed by the powder and coarse particles supplied onto the table 14 by using the pressing means 13, and the table 14 and the roller 12 are pressed.
Under the rotation of, the crushed material and the coarse particles are crushed by the action of compression and shear. The crushed material moves in the outer peripheral direction by the centrifugal force caused by the rotation of the table 14, and a hot air flow is introduced from a nozzle (not shown) provided around the table 14 to flow upward to entrain the crushed material and dry the crushed material. Are performed at the same time, and the crushing action is promoted.

Reference numeral 16 denotes a classifying means, and a casing 18
The classification blade 17 that is housed in the top of the and is attached to the rotating shaft 54 is rotatable. More specifically, the classifying means 16 is provided in a classifying chamber 39 formed by an inner cylinder 40 partitioned in the casing 18. The inner cylinder 40 has a conical lower part and a cylindrical upper part 4 having an upper cylindrical part.
2 is formed on the lower end of the inner cylinder 40.
1 is opened.

Reference numeral 46 denotes a partition tube which is formed into a conical shape and is attached to the outside of the lower cone of the inner tube 40 to partition the casing 18 together with the straight tube portion 42.
A passage 47 is formed therein, and serves as an air flow passage for the air flow of the crushed material from the crushing unit 38.

An adjusting vane 48 having a variable opening degree is circumferentially arranged on the upper portion of the straight cylindrical portion 42 so that the flow rate of the air flow accompanied with the pulverized material flowing from the passage 47 into the classification chamber 39 can be adjusted.

In the classification means 16, the classification chamber 39
The classification operation is performed under the equilibrium action of the centrifugal force and the resistance force that act on the particles corresponding to the particle size of the pulverized material that has flowed into the
The particles are classified into coarse particles and fine particles corresponding to a predetermined classification particle size.

A second conveying means 24 for conveying the coarse particles classified by the classifying means, for example, a screw feeder or the like is arranged horizontally across the casing 18 in the opening 41. The second transfer means 24 is driven by a drive source 26, and the coarse particles are simply mechanically transferred in the direction of arrow B without using an air flow.

Below the second conveying means 24, a mixture 36 of crushed material and coarse particles conveyed by the second conveying means 24 is provided.
The first conveying means 20 for conveying the powder to the powder portion 38, for example, a screw feeder or the like is arranged in the horizontal direction across the casing 18. The second transport means 20 is driven by a drive source 22.

A supply pipe 32 for supplying the crushed material 30 is attached to one end of the first conveying means 20, and a connecting passage 27 for connecting to the outlet end of the second conveying means 4 is attached to the middle portion. A supply port 34 for supplying the mixture 36 to the central portion of the crushing unit 8 is attached to the other end.

An airtight supply unit 28 is interposed in the middle of the connection passage 27 so that the coarse particles can be conveyed by the second conveying means 24.
From the outlet end of the above to the intermediate portion of the first conveying means 20 through the airtight supply valve, and together with the crushed material 30, the mixture 36 is simply mechanically conveyed in the direction of arrow A without using an air flow.

Thus, from the inner cylinder 40 of the classification chamber 39 to the second
A continuous coarse particle passage is formed up to the conveying means 24, the connecting passage 27, the airtight supply valve 28, the first conveying means 20, and the supply port 34, and the coarse particles are returned to the crushing section 38 to be crushed. The air pressure of the crushing section 38 acts on the crushing portion 38, but since the air flow is substantially shut off by the airtight supply valve 28, the air is not communicated from the coarse grain opening 41 of the classifying chamber 39 and the classification is performed. In the chamber 39, the coarse particles are prevented from re-flying by the air flow to form a circulating flow.

Next, the operation will be described. Vertical roller mill 10
When the table 14 is rotated by the driving device to rotate the roller 12 through the material layer, the crushed material 30 is supplied through the supply pipe 32 and the second conveying means 20 supplies the second material.
The coarse particles conveyed through the conveying means 24 and the airtight supply valve 28 are supplied as a mixture 36 to the crushing section 38 and crushed by the one into which the hot air flow is introduced to be a crushed product.

This crushed material is crushed in the crushing chamber 38 while forming a circulating flow due to the introduction airflow and a drop due to gravity, and only the crushed material having a reduced particle size is accompanied by the airflow, as indicated by arrow a. After passing through the passage 47, it further flows into the classification chamber 39 through the adjusting vane 48 as shown by the arrow b.

In the classifying chamber 39, the crushed material is classified by the classifying means 16 and classified into coarse particles d and fine particles c corresponding to a predetermined classification particle size. The fine particles c are accompanied by the air flow, flow in the duct 50, and are sent from the discharge port 52 as the crushed product 56 to the next step for processing.

The coarse particles d fall in the inner cylinder 40 by gravity without reaching the air flow, and reach the coarse particle opening 41.
The conveying means 24, the connection passage 27, the airtight supply valve 28, the first conveying means 20, and the supply port 34 are continuously returned to the crushing section 38 through the coarse particle passage, and together with the crushed material 30, the crushing section 38 as the mixture 36. Internal crushing is performed by crushing. Thus, in the classification chamber 39, coarse particles are prevented from re-flying by the air flow to form a circulation flow, which reduces the particle concentration of the pulverized material in the classification chamber 39, and the classification performance of the classification means 16 and the pulverization. The crushing performance of the part 38 can be improved. In this embodiment, the crushing performance of the vertical roller mill 10 is as shown in Table 1 when compared with the conventional technique.

[0024]

[Table 1]

As described above, according to this embodiment, in the ultrafine pulverization of the crushed material, the classification performance and the related pulverization performance can be improved as compared with the prior art, and a crushed product composed of ultrafine particles can be obtained. it can.

[0026]

As described above, according to the present invention,
Of the crushed material from the crushing unit, coarse particles classified by the classifying means are discharged from the classifying room by the transporting means, and are effectively prevented from re-flying into the classifying room to form a circulation flow. It is possible to improve the classification performance of the classification means and the crushing performance of the crushing section by reducing the particle concentration of the so as to obtain a crushed product composed of classified ultrafine particles, and to avoid adding an independent classifier. it can. Further, the structure and operation adjustment of the vertical roller mill can be simplified.

[Brief description of drawings]

FIG. 1 is a sectional view of a vertical roller mill showing an embodiment of the present invention.

[Explanation of symbols]

 10 Vertical Roller Mill 12 Roller 14 Table 16 Classifying Means 18 Casing 20 First Conveying Means 24 Second Conveying Means 38 Crushing Section 39 Classifying Chamber 40 Inner Cylinder 41 Coarse Grain Port 52 Discharge Port 56 Crushed Product

Claims (2)

[Claims] 1. A vertical roller mill having a crushing unit composed of a roller and a table, the classifying unit being housed in a casing, wherein the classifying unit is provided in a classifying chamber formed by an inner cylinder partitioned in the casing. The second conveying means for classifying the crushed material from the crushing unit into coarse particles and fine particles, and for conveying the coarse particles classified by the classifying means is connected to the coarse particle port opened at the lower end of the inner cylinder to connect to the casing. The first conveying means for arranging the mixture of the crushed material and the second conveying means to the crushing section is arranged below the second conveying means and reduces the particle concentration of the crushed material in the classification chamber. A vertical roller mill characterized in that a crushed product consisting of fine particles classified by the above-mentioned classification means is obtained from an outlet. 2. The vertical roller mill according to claim 1, wherein an airtight supply valve is provided in an intermediate portion of a connection passage between the first conveying means and the second conveying means.