JP2004358388A - Method of and apparatus for observing crushing condition of vertical mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to observe a crushing condition inside a mill at the time of operation. <P>SOLUTION: At a lower portion within a casing 2 there is disposed a crushing unit 3 consisting of a turntable 4 and a crushing roller 5 rotating the turntable 4. Further, above the crushing unit 3 there is provided a cone-shaped chute 13, and above such cone-shaped chute 13 there is disposed a rotating separator 12. Raw materials supplied from a raw material supplying device 6 to the turn table 4 are crushed by the crushing unit 3. Next, the crushed materials blown up by a transporting gas 14 are sorted by the rotating separator 12, while crude powder 21 is returned back along the inner surface of the cone-shaped chute 13. A portion of such crude powder to be returned back is extracted out through a pipeline 16. The bulk specific gravity of the extracted crude powder is measured using a measurement instrument 24, thus observing the crushing condition inside the mill by virtue of measurement values of the measurement instrument 24 which can be used to confirm whether or not particle size of such crude power 21 has become large. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for externally monitoring the state of pulverization of a vertical mill, and particularly to a method for pulverizing a heat-softening substance that reaches a melting point by the heat of pulverization of a pulverizing unit as a material to be pulverized. The present invention relates to a method and an apparatus for monitoring a pulverized state of a vertical mill so as to constantly monitor a pulverized state inside a type mill.
[0002]
[Prior art]
FIG. 2 shows an example of a vertical mill as one of pulverizers for pulverizing a raw material as an object to be pulverized. That is, vertical mill 1 shown in FIG. 2, the lower position in the casing 2, the grinding zone consisting rotatably installed a turntable 4 and grinding rollers 5 for pressing is in rolling on the rotary table 4 3 to pulverize the raw material supplied from the raw material supply device 6 to the center of the turntable 4. Rotating table 4 constituting the crushing part 3, by the motor 7 as a drive unit Yes allowed to be rotated at a low speed through a speed reducer 8, the grinding roller 5 by a fluid pressure cylinder 9 in the rotating table 4 The pressing force is adjusted. The top center of the casing 2 as the upper position of the crushing part 3, provided with a discharge opening 10 of the carrier gas and fines, the lower side of the discharge port 10, the separator 12 of the rotary rotationally driven by the motor 11 Is provided. The central portion located in the coarse powder as the return powder is separated from the fines by rotary separator 12 of the (semi product) on a rotary table 4 between the separator 12 and the grinding zone 3 of the rotary Is provided with a slit 13a through which the powder blown up by the carrier gas 14 can pass. coarse powder along the inclined faces are so as to fall slipping.
[0003]
Further, a gas inlet 15 for blowing up the powder pulverized by the pulverizing unit 3 is provided at a lower position of the casing 2, and the powder is supplied from the gas inlet 15 so that the powder is slit into the cone-shaped chute 13. It is blown up through 13 a and classified by the rotary separator 12.
[0004]
The vertical mill 1 having the above configuration is used for pulverizing various raw materials. Among the raw materials, for example, the raw material reaches a melting point due to the pulverizing heat generated in the pulverizing unit 3 during pulverization and is softened so that pulverization cannot be performed. In the case of a thermosoftening substance such as a toner, the vertical mill 1 is operated while a low temperature state is maintained by putting a low temperature inert gas or a refrigerant such as dry ice into the casing 2.
[0005]
However, when the above-mentioned heat-softening substance is pulverized by the vertical mill 1, if there is a shortage of the refrigerant, the pulverization of the heat-softening substance by the pulverization heat generated at the time of pulverization in the pulverization unit 3. object reaches the melting point, the progress of the softened pulverization can further advances state hard.
[0006]
If such a state is left, the softening of the heat-softening substance causes the welding of the particles to occur, and the particle size of the pulverized product becomes large, resulting in a defective product. You will lose quality. Further, when the heat softenable material begins to soften, object to be crushed accumulated in large quantities vertical mill 1, it comes in a state that must stop the operation of the mill.
[0007]
Therefore, it is required to ground state inside the mill constantly monitors, to prevent production of defective products.
[0008]
In order to reduce the amount of defective products generated by the vertical mills that have been proposed so far, a rotary separator that classifies the pulverized powder accompanying the carrier gas into fine powder and coarse powder is classified. particle size of fine grains directly related to the powder density, particle size after the higher the powder density classification narrows the particle size after classification the lower powder density Conversely Noting that coarser, before the classification comprises a powder concentration measuring apparatus for detecting a powder concentration of carrier gas in real time, taking out the transporting gas in the mill outside to guide to the powder concentration measuring apparatus, it is detected by the powder concentration measuring apparatus By controlling the rotation speed of a rotary separator in accordance with the powder concentration, the amount of defective products can be greatly reduced (for example, see Patent Document 1).
[0009]
When a low-melting substance such as a resin is pulverized by a vertical mill, a cooling jacket is provided in a raw material supply device into the vertical mill as a device for cooling an object to be pulverized with a low-temperature inert gas. the inlet of the jacket, along with connecting the inert cryogenic liquefied gas supply system, the outlet of the cooling jacket is connected to the feed inlet portion of the material supply device, the inert gas is vaporized in the cooling jacket low temperature the material supply device introducing to have those so as to cool the material directly (e.g., see Patent Document 2).
[0010]
[Patent Document 1]
JP 2001-340780 A [Patent Document 2]
Japanese Utility Model Laid-Open No. 5-13537
[Problems to be solved by the invention]
However, stable quality by the those described in Patent Document 1, that to detect the powder density is taken out carrier gas from the side wall of the casing, controls the rotational speed of the rotary separator according to the powder concentration to obtain a product having, but thereby is intended to reduce the generation amount of defective products, not intended to be adapted to check the pulverized state removed ground product directly in the milling of heat-softenable material.
[0012]
As described above, the fact that a pulverized material is extracted during the operation of the vertical mill to check the pulverized state in the mill has not been proposed so far.
[0013]
The present invention is intended to provide a constantly pulverized state monitoring method and apparatus of the vertical mill to be monitored to extract the partially crushed state of the mill pulverized material during operation of the vertical mill It is.
[0014]
[Means for Solving the Problems]
In order to solve the above problems, the present invention extracts a part of coarse powder which is pulverized by a rotary table and a pulverizing roller, blown up by a carrier gas, and classified by a separator and returned to the rotary table, outside the mill. After that, the bulk specific gravity of the extracted coarse powder is measured, and a method for monitoring the pulverization state inside the mill based on the measured value of the bulk specific gravity is provided at a position above a pulverization unit including a rotary table and a pulverization roller in a casing. At the required location of the cone-shaped chute, one end of a pipe for extracting a part of coarse powder that is classified by the separator and returned along the cone-shaped chute and returned to the rotary table is connected to the inside of the cone-shaped chute. was opened, and includes a coarse powder collector to the other end of the pipe, the collected coarse powder in the collecting device for measuring the sieve sieved, the bulk specific gravity of the remaining crude powder sieve weighing Container and the measuring device And comprising an arithmetic unit for determining the pulverized state by the value structure.
[0015]
During the operation of the vertical mill, the coarse powder in the pulverized material that is blown up and returned by the carrier gas is extracted and the bulk specific gravity is measured.As a result of the measurement, when the bulk specific gravity tends to increase, the particle size of the coarse powder is increased. It is sensed that is getting larger. Accordingly, when the object to be pulverized with the thermosoftening substance is pulverized, it is possible to monitor that the object to be pulverized has reached the melting point and has started to soften.
[0016]
In addition, when a plurality of measuring instruments having a bulk specific gravity are provided, the measuring powder can be continuously supplied to the measuring apparatus even when measuring the bulk specific gravity of the coarse powder.
[0017]
Further, when supplied to the internal mill extracted crude powder was recovered, effectively producing a fine powder.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
Figure 1 shows an embodiment outline of the embodiment of the present invention, in a vertical mill 1 with a same structure as the vertical mill 1 shown in FIG. 2, the coarse powder (half between the slits 13a of the cone-shaped chute 13 One end of a pipe 16 having a required diameter inserted through the side wall of the casing 2 and inserted into the mill is connected to the surface on which the product (product) slides down, and is opened inside the chute 13. The pipe 16 is inclined so that the other end located outside the casing 2 is lower, the other end is connected to the cyclone 17, and a part of coarse powder sliding down the cone-shaped chute 13 is extracted through the pipe 16, Cyclone 17 is to be collected.
[0020]
A bag filter 18 and a suction fan 19 are installed downstream of the cyclone 17, and the gas 14 and the fine powder 20 separated by the cyclone 17 are guided to the bag filter 18 by a line 22, where the fine powder 20 is collected. Thus, the gas is released through the suction fan 19.
[0021]
On the other hand, a vibrating sieve 23 for sieving the coarse powder (semi-finished product) 21 separated by the cyclone 17 is installed at a position below the cyclone 17, and the coarse powder taken out from the outlet 17 a at the lower end of the cyclone 17 is removed. 21 is supplied onto the vibrating sieve 23. Further, a measuring device 24 for measuring the bulk specific gravity of the coarse powder 21 sifted by the vibrating sieve 23 and remaining on the vibrating sieve 23 is installed, and the measured value of the bulk specific gravity by the measuring device 24 is input to obtain a particle size. And a control panel 26 for controlling the operation of the vertical mill 1 based on the information of the calculator 25.
[0022]
The measuring device 24 for measuring the bulk specific gravity of the coarse powder includes a container 24a for measuring bulk specific gravity as a predetermined constant capacity and a measuring portion 24b, and the coarse material supplied from above the vibrating sieve 23 into the container 24a. The bulk specific gravity of the coarse powder 21 can be measured by measuring the weight of the powder 21.
[0023]
Further, the coarse powder 21 collected through the mesh of the vibrating sieve 23, the coarse powder 21 supplied to the container 24a of the bulk specific gravity measuring device 24 and taken out after the measurement, As shown by A in the figure, the collected fine powder 20 is collected and supplied to the raw material supply device 6 by an arbitrary conveying means, and returned to the inside of the mill by the raw material supply device 6.
[0024]
Reference numeral 27 denotes a line for introducing the coarse powder 21 remaining on the vibrating sieve 23 into the container 24a of the measuring device 24. Other vertical mills 1 which are the same as those in the vertical mill 1 shown in FIG.
[0025]
The material to be crushed of the heat-softening substance is introduced as a raw material into the raw material supply device 6 and supplied to the inside of the mill from the raw material supply device 6, and a low-temperature inert gas or a refrigerant such as dry ice is charged into the inside of the mill. When operating the mill 1, raw material supplied to the central upper surface of the turntable 4 is ground in the grinding unit 3 comprising a grinding roller 5 for pressing is in rolling the rotary table 4 and the rotary table 4.
[0026]
Crushing section 3 of the vertical mill 1, the raw material is preset in proper conditions so normal grinding to be micronized is performed, a normal state for normal operation which is produced fines (product) is It has become.
[0027]
In such a normal operation, the pulverized material pulverized in the pulverizing section 3 is passed through the slit 13a of the cone-shaped chute 13 with fine powder and coarse powder accompanied by the carrier gas 14 blown up from below. Reach 12. The carrier gas 14 that has reached the separator 12 and the pulverized product of the fine powder and the coarse powder are classified by the separator 12, and the fine powder (product) is recovered by being discharged from the discharge port 10, and is not discharged as the coarse powder (semi-product). fines fell along the surface without slits 13a of the cone-shaped chute 13, it will be returned onto the rotary table 4, that is ground in the grinding unit 3 together with the raw material supplied from the material supply device 6 Become.
[0028]
The pulverized material including a part of the coarse powder (semi-finished product) returned along the inner surface of the cone-shaped chute 13 enters the pipe 16 opened on the surface of the chute 13 and is sucked by the suction fan 19. As a result, it is extracted through the pipe 16. The pulverized material extracted through the pipe 16 is collected in the cyclone 17, where it is separated into coarse powder 21 and fine powder 20, and the fine powder 20 is guided to the bag filter 18 to be collected and gas is released. On the other hand, the coarse powder 21 collected by the cyclone 17 is taken out from the lower end of the cyclone 17 and supplied to the vibrating sieve 23. The coarse powder 21 supplied to the vibrating sieve 23 is sieved and sieved, and if there is a coarse powder having a large particle size that remains on the vibrating sieve 23, the coarse powder 21 is supplied to a container 24a for measuring bulk specific gravity. become.
[0029]
In the above, when the pulverized state in the vertical mill 1 is operating normally, a large particle size of the coarse powder 21 does not suddenly occur, and the bulk specific gravity measuring device 24 determines the bulk specific gravity of the coarse powder. Even when measured, the bulk specific gravity does not increase.
[0030]
However, due to a combination of various conditions such as a small amount of the refrigerant inside the mill, the material to be pulverized of the thermosoftening material reaches the melting point due to the pulverization heat generated when pulverized in the pulverization unit 3 and begins to soften. As described above, welding of the particles occurs. In such a state, the particle size of the coarse powder 21 rapidly increases, and the coarse powder 21 of the pulverized material extracted from the inner surface of the cone-shaped chute 13 through the pipe 16 contains a large particle size. .
[0031]
When the coarse powder 21 having a large particle size due to welding of the particles is supplied from the cyclone 17 to the vibrating sieve 23, the coarse powder 21 remains on the vibrating sieve 23 even after being sieved and is supplied to the container 24a for measuring the bulk specific gravity one after another. Will be coming. When a certain amount of the coarse powder 21 is supplied into the container 24a with a certain capacity, the weight of the coarse powder 21 is determined by measuring the weight with the measuring device 24. When the particle size of the coarse powder 21 increases, the bulk specific gravity increases. Therefore, the arithmetic unit 25 requires that the bulk specific gravity is larger than a certain level from the value measured by the measuring device 24.
[0032]
As described above, when the bulk specific gravity of the coarse powder 21 suddenly increases, an abnormality occurs in the pulverized state inside the mill, that is, the heat-softening substance starts to soften due to the heat of the pulverization and the particles are welded to each other. Therefore, by monitoring this from the outside, it is possible to detect the pulverization state inside the mill during the operation of the vertical mill 1.
[0033]
As described above, when it is detected that the pulverization state inside the mill is abnormal, the amount of the refrigerant into the mill is increased by the vertical mill operation panel 26 so that the coarse powder of the heat-softening substance becomes the melting point. It is controlled so that it is crushed in a state where it does not reach.
[0034]
In the embodiment of the present invention, when the bulk specific gravity measuring device 24 measures the bulk specific gravity of the coarse powder 21 supplied to the container 24a as one unit, the supply of the coarse powder 21 to the container 24a is stopped. Although it is shown as a batch type, at least two similar measuring devices 24 are provided, and coarse powders 21 sifted by the vibrating sieve 23 are alternately supplied into the container 24a. and so on, it can be continuously to be able to measure the bulk density.
[0035]
The present invention is not limited to the embodiment described above, for example, in place of the material supply device 6 of the vertical mill 1, to adopt a screw conveyor system so as to perform the supply of the raw material It goes without saying that various changes may be made without departing from the spirit of the present invention.
[0036]
【The invention's effect】
As described above, according to the method and apparatus for monitoring the pulverized state of a vertical mill of the present invention, the following excellent effects can be obtained.
(1) After extracting a part of the coarse powder which is pulverized by the rotary table and the pulverizing roller, blown up by the carrier gas, and classified by the separator and returned to the rotary table, is extracted outside the mill; A method of measuring the bulk specific gravity and monitoring the pulverized state inside the mill based on the measured value of the bulk specific gravity, and a necessary portion of a cone-shaped chute provided above a pulverizing section including a rotary table and a pulverizing roller in a casing. One end of a pipe for extracting a part of coarse powder which is classified by a separator and returned to the rotary table along the cone-shaped chute is connected to open the inside of the cone-shaped chute. end to comprise a coarse powder collector, and sieves the collected coarse powder in the collecting device sieved, a metering device for measuring the bulk specific gravity of the remaining crude powder sieve, metering unit value To determine the grinding state Since it is a device equipped with a calculator, it can always sense and monitor the pulverized state by measuring the bulk specific gravity that changes according to the particle size of the coarse powder extracted during the operation of the mill, and the normal operating state This makes it possible to detect the occurrence of an abnormality and prevent the production of defective products.
(2) According to the above (1), in the case of a thermosoftening substance in which the coarse powder reaches the melting point and starts to be softened by the pulverization heat of the pulverizing unit, the bulk specific gravity of the extracted coarse powder is measured to determine the melting point. , It is possible to know whether or not the welding of the particles has occurred, and it is possible to improve the pulverized state without stopping the operation of the mill.
(3) Along with the above (2), a new raw material that can be pulverized using a vertical mill can be easily found, and the application range of the vertical mill can be easily confirmed.
(4) By installing a plurality of measuring devices having a bulk specific gravity, coarse powder having a large particle size sieved can be continuously supplied to the measuring devices.
(5) Fine powder (product) can be produced effectively by collecting the extracted pulverized material and returning it to the inside of the mill.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an embodiment of a method and an apparatus for monitoring a pulverized state of a vertical mill according to the present invention.
FIG. 2 is a schematic view showing an example of a conventional vertical mill.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vertical mill 2 Casing 3 Pulverizing part 4 Rotary table 5 Pulverizing roller 6 Material supply device 10 Outlet 12 Separator 13 Cone-shaped chute 13a Slit 14 Carrier gas 16 Pipe 17 Cyclone (collection part)
20 fine powder 21 coarse powder 23 vibrating sieve (sieve)
24 Measuring device for bulk specific gravity 25 Computing device 26 Vertical mill operation control panel

Claims (4)

After extracting a part of the coarse powder which is pulverized by the rotary table and the pulverizing roller, blown up by the carrier gas, and classified by the separator and returned to the rotary table, the bulk specific gravity of the extracted coarse powder is extracted. A method for monitoring the pulverized state of a vertical mill, comprising measuring and monitoring the pulverized state inside the mill based on the measured value of the bulk specific gravity. A part of coarse powder which is classified by a separator at a required position of a cone-shaped chute provided above a pulverizing section comprising a rotary table and a pulverizing roller in a casing and returned to the rotary table along the cone-shaped chute. One end of a pipe for extracting water is connected to open the inside of the cone-shaped chute, and a coarse powder collector is provided at the other end of the pipe, and coarse powder collected by the collector is sieved. Sieve, a measuring device for measuring the bulk specific gravity of the coarse powder remaining on the sieve, and a calculator for judging the pulverized state based on the value of the measuring device, the pulverizing state of a vertical mill monitoring equipment. 3. The apparatus for monitoring a pulverized state of a vertical mill according to claim 2, wherein a plurality of measuring devices having a bulk specific gravity are provided so that the bulk specific gravity of the coarse powder remaining on the sieve can be measured alternately. 4. The apparatus for monitoring a pulverized state of a vertical mill according to claim 2, wherein the coarse powder extracted through the pipe is collected and returned to the inside of the mill.

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