JP2518982B2 - Vertical mill crusher - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crusher for crushing ores such as cement clinker by a vertical roller mill.

[0002]

2. Description of the Related Art Conventionally, when crushing objects to be crushed such as cement clinker, cement raw material, slag, and ores, such objects to be crushed are preliminarily processed by a vertical roller mill having excellent coarse crushing efficiency. There is a technique of pulverizing and then pulverizing with a tube mill excellent in fine pulverization efficiency.

As such a prior art, there is Japanese Patent Laid-Open No. Sho 61-61.
There is an invention described in JP-A-238349, and in the present invention, as shown in FIG. 4, the material to be crushed introduced from the raw material introduction port 30 is pulverized in the vertical roller mill 31 and is passed through the bucket elevator 32 to the separator 33. The coarse powder introduced and classified in the separator 33 is introduced into the tube mill 34, and the powder pulverized in the tube mill 34 is returned to the bucket elevator 32 and introduced again into the separator 33. The fine powder classified by the separator 33 is taken out from the chute 35 as a product. this,
Hereinafter, what is crushed by the vertical roller mill 31 in one step will be referred to as a one-pass crusher.

By the way, in a vertical roller mill, a plurality of rollers are arranged at intervals in the circumferential direction on a table which rotates around a vertical axis, and an object to be crushed supplied to the center of the table is placed between the table and the rollers. It crushes and crushes it by making it bite into. Therefore, since a large pressing force is constantly generated between the roller and the table, no matter what kind of object to be crushed, vibration is generated due to the crushing.

The mechanism of this vibration is as shown in the schematic view of crushing in FIG. 5, in which the object S to be crushed is caught between the table 31a and the roller 31b by the rotation of the table 31a around the vertical axis, and It is crushed and crushed by the pressing force of 31b. For example, in a one-pass crusher,
When a cement clinker is crushed as the object to be crushed S, the bulk specific gravity before crushing is usually about 1.5, and the bulk specific gravity after crushing is about 2.5. Therefore, the layer thickness before being bitten by the roller 31b is T, and the layer thickness t immediately after being crushed and crushed is t.
Then, T / t = 1.67, that is, the layer thickness displacement amount ΔT
(= T−t) is 0.4T. On the other hand, the table 31a
The peripheral speed of the machine depends on the size of the mill, but is 3.5
m / sec, and the object S to be crushed on the table 31a which rotates at such a high speed is the layer thickness displacement amount ΔT.
= 0.4T, a large vibration occurs due to crushing while frequently changing. The above is the mechanism of vibration generation in the vertical roller mill.

When such a vertical roller mill 31 is used as a pre-crusher, for example, when crushing a cement clinker, a crushed object having a particle size of 50 mm to 1 mm is crushed to about 15 mm to 0.01 mm. Therefore, a stronger pressing force is required as compared with a commonly used vertical roller mill. However, when trying to apply a strong pressing force for efficient pulverization, the pulverized material supplied to the vertical roller mill for pre-milling has many coarse particles, which is more than that of a commonly used vertical roller mill. Large vibration occurs.
Therefore, in order to suppress this vibration, it is the actual situation that the pressing force of the roller is used at a place considerably lower than a desired value in terms of grinding efficiency.

Further, since the crushed product crushed by the one-pass crushing device also contains a large amount of coarse particles, when it is supplied to the tube mill which is the secondary crushing step, the diameter of the ball which is the crushing medium of the tube mill remains large. I need to leave. Since the tube mill originally has a property that the crushing efficiency is deteriorated when the ball diameter is large, it is difficult to improve the crushing efficiency of the tube mill by crushing with large balls left.

As a prior art for solving some of these problems, there is one shown in FIG. In this prior art,
The material to be crushed from the charging port 40 is fed to the vertical roller mill 4
1 is crushed, the crushed crushed product is put into the sieving device 43 from the bucket elevator 42, and the sieving net 44 of the sieving device 43 is used to crush the crushed product crushed by the vertical roller mill 41, for example, the particle size. Coarse particles of 2.5 mm or more are separated, and the coarse particles are returned from the chute 45 to the vertical roller mill 41 and pulverized again. The remaining fine powder separated by the sieving device 43 is supplied from the chute 46 to the tube mill 47 for the secondary grinding process. Tube mill 47
The powder pulverized by is classified by the separator 48,
The coarse powder is returned to the tube mill 47 again, and the refined powder is discharged as a product. Such prior art is disclosed in, for example, Japanese Patent Laid-Open No. 63-116751 or Japanese Patent Laid-Open No. 2-71856, and will be hereinafter referred to as a sieve circulation crushing device.

The sieve circulating crushing device shown in FIG.
The crushed product from the vertical roller mill 41 still contains a large amount of coarse particles (for example, a particle size of 2.5 mm or more and about 30%). Therefore, the crushed product should be sized by using a sieving device 43 such as a vibrating screen. Coarse particles of 2.5 mm or more are separated, the coarse particles on the sieve are returned to the vertical roller mill 41, re-pulverized with a new object to be pulverized, and only the fine powder under the sieve is supplied to the tube mill 47 in the secondary pulverization process. To do. By this,
The crushing medium of the tube mill 47, for example, the crushing balls, is further reduced in diameter to a size smaller than the size of the crushing balls of the tube mill 34 in the above-mentioned one-pass crushing device, and the tube mill 4
We are aiming to improve the grinding efficiency of 7.

[0010]

However, in this sieving and circulating crushing apparatus, among the crushed objects crushed by the vertical roller mill 41, for example, coarse particles having a particle size composition of 2.5 mm or more (particle size of 2.5 mm) are used. ~ 15 mm), the particle size composition of the crushed object of the roller mill is almost the same as the particle size composition of the new crushed object, or conversely, the proportion of coarse particles may increase.
The particle size composition may be substantially the same as the one-pass crusher described above, or may be coarse. Therefore, as a matter of course, as with the one-pass crusher, a large vibration is generated.

The vertical roller mill which generates a large amount of vibration as described above needs to be mechanically designed to be seismic resistant, which requires a large structural member, which causes a cost increase. Therefore, how to reduce this vibration is an important issue.

By the way, the properties of a new object to be crushed (granularity constitution, crushability, etc.) are not always constant, but constantly fluctuate. That is, in response to a new change in the particle size composition of the object to be ground, the vibration level greatly changes and the power consumption of the vertical roller mill also changes to a considerable extent. If the material to be ground becomes difficult to grind, the grinding capacity of the grinding plant will decrease, so the amount of material to be ground supplied to the vertical roller mill will decrease, and the thickness of the raw material layer entrapped between the roller and the table will decrease. To do. As a result, the vibration level increases and the power consumption of the vertical roller mill decreases,
Reduce the milling capacity of the plant. On the contrary, since the crushing ability of the crushing plant is increased when the crushability is increased, the amount of the crushed material supplied to the vertical roller mill is increased, and the raw material layer thickness between the roller and the table is increased. Although the vibration level is reduced, the thickness of the raw material layer is increased, so that the pressure receiving area of the roller pressing force is increased, the substantial crushing pressure per unit area is reduced, and the crushing efficiency is reduced. Then, the influence of the new property change of the crushed substance also affects the operating condition of the entire plant, resulting in extremely unstable operation.

That is, the crushed product of the vertical roller mill 41 is separated into the upper part (coarse particles) and the lower part (fine powder) by a sieving device 43 such as a vibrating screen, and the coarse particles are returned to the vertical roller mill 41. Tube mill 47 for secondary pulverization process of fine powder
Since it is supplied to the vertical roller mill 4
1 depends on the particle size of the crushed product. However, the particle size of the pulverized product of the vertical roller mill 41 is not always constant, and is constantly changed due to the influence of the property change of the new pulverized product or the pulverized state of the vertical roller mill 41. To do. Therefore, on the side of the vertical roller mill 41, even if the supply amount of a new object to be pulverized is constant, the amount on the sieving (coarse particles) that circulates constantly fluctuates, so that the amount of material to be supplied to the vertical roller mill 41 is constantly changed. The total amount of pulverized material will fluctuate, and the pulverized state will constantly change. Actually, the supply amount of the new pulverized material is not always constant, so that the total supply amount to the vertical roller mill greatly varies synergistically, and the vibration and the power consumption of the mill constantly change.

Further, as described above, the fine powder under the sieve is supplied to the tube mill 47 side in the secondary crushing step, but this amount also changes constantly, so that the operation state is not constant and unstable operation is performed. Becomes

As described above, in the sieving and circulation apparatus, the amount of circulation to the vertical roller mill 41 and the amount of supply to the tube mill 47 cannot be arbitrarily optimized according to the change in the property of a new object to be crushed. Further, since the whole amount of the crushed product crushed by the vertical roller mill 41 is put into the sieving device, a large sieving means capable of processing the whole amount put into the vertical roller mill 41 is required.

In view of the above problems, the present invention returns a part of the crushed product crushed by the vertical roller mill to the vertical roller mill as it is, and throws it into the vertical roller mill together with a new object to be crushed, so that it is caught in the roller. The bulk specific gravity of the crushed object is increased to reduce the layer thickness displacement amount, thereby reducing the vibration from the source itself, and separating the crushed product by the sieving means to distribute it to the secondary crushing process. It is an object of the present invention to provide a crushing device using a vertical roller mill that can reduce the size of a crushed product and exhibit the best performance by these.

[0017]

To achieve the above object, according to the Invention The milling device according to vertical mill according to claim 1, a vertical roller mill for grinding the grinding object pressed against the roller on the table, 該竪Type mill with a vertical mill in which a sieving means for sieving crushed products crushed by a roller mill
In, part of the crushed product crushed by the vertical roller mill
Setting a distribution means for returning to the vertical roller mill in the intact
A control circuit for controlling the distribution ratio of the distribution means is provided.
The amount of displacement of the layer thickness of the material to be crushed into the vertical roller mill is small.
It is characterized by the fact that it has been cut .

Further, the crushing device by the vertical mill according to claim 2
Between the vertical roller mill and the sieving means.
A part of the crushed product crushed by the mill is kept as it is
-Distributing means for returning to the la-mill is provided, and the
The crushed products other than those returned to Ramil were supplied to the sieving means.
And are characterized by.

Further, the crushing device by the vertical mill according to claim 3
Is a vertical roller mill on a sieve that has been screened by sieving means.
And sift to the downstream side of the sieving means.
The part of the under tough Rui as it is in the vertical roller mill
It is characterized in that a distribution means for returning is provided.

Further, the crushing device using the vertical mill according to claim 4
Is the secondary crushing of the bottom of the sieve that has been sieved by sieving means.
It is characterized in that a tube mill is provided.

[0021]

With the above-mentioned structure, the roller is pressed against the table, the crushed object is caught between the table and the roller, and the crushed and crushed product is discharged from the vertical roller mill and discharged from the vertical roller mill. Tomo returning to the vertical roller mill a portion which was partitioned ground material in distribution means as it is
, The back part of the upper sieve separated is supplied to the sieve means vertical roller mill, it is pulverized with a new object to be crushed fed into the vertical roller mill.

The amount of crushed product distributed by this distribution means is
A vertical circuit is controlled by a control circuit that controls the distribution ratio of the distribution means.
-The layer thickness displacement of the object to be crushed is reduced.
Controlled as.

As a result, the crushed product from the roller mill is mixed into the new crushed product, the filling rate is increased, and the bulk specific gravity of the crushed product caught between the table and the roller can be increased, and the voids of the crushed product are increased. By reducing the ratio, the vibration of the vertical roller mill can be significantly reduced.

Therefore, it is possible to apply a high roller pressing force that is optimum for crushing efficiency, and as a result, it is possible to significantly improve the crushing ability. Further, by increasing the bulk specific gravity of the material to be crushed, it is possible to reduce the roller rolling resistance of the vertical roller mill, which also makes it possible to improve the grinding efficiency.

The distribution means and the sieving means are arranged in series.
Then, by returning a part of the crushed product to the vertical roller mill as it is, the displacement of the layer thickness can be reduced to significantly reduce the vibration and the crushed product to be distributed to the secondary crushing process can be reduced. .

In particular, the crushing device by the vertical mill according to claim 4
According to the above, since only fine powder under the sieve is put into the tube mill, a large diameter ball in the tube mill becomes unnecessary,
As a result, the pulverization efficiency of the tube mill can be significantly improved.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing an embodiment of the present invention. As shown in the figure, a material to be crushed is cut out from a raw material hopper 1 by a constant quantity feeder 2 at a constant weight per unit time, and a vertical roller mill 3 is cut. It is supplied to the inlet 3c. Then, as for the crushed product crushed between the table 3a and the roller 3b of the vertical roller mill 3, substantially all of the crushed product is taken out from the chute 3d below the table 3a. The crushed product taken out from the chute 3d is transported by the bucket elevator 4 and guided to the distribution means 5. A part of the crushed product from the vertical roller mill 3 is returned to the inlet 3c of the vertical roller mill 3 through the chute 6 by the distributing means 5, and the remaining crushed product is discharged from the chute 7 in series with the distributing means 5. Means 8
Is distributed to be supplied to. And sieving means 8
Of the crushed products that have been screened with, shoot 9 on the screen.
It is returned to the inlet 3c of the vertical roller mill 3 via the, and the bottom of the sieve is supplied to the tube mill 11 via the chute 10.

The crushed product supplied to the tube mill 11 is
After being crushed by balls, which are crushing media provided in the body of the tube mill, it is introduced from the bucket elevator 12 at the outlet to the separator 13 such as an air flow separator, and the coarse powder after the classification is again discharged from the chute 14 to the tube mill. It is thrown into 11 and re-pulverized, and the fine powder is taken out from the chute 15 as a product.

The distribution means 5 uses a distribution damper having a distribution blade 5a as shown in FIG. 2, and the tilt angle is adjusted by rotating the shaft 5b of the distribution blade 5a provided at the center. The distribution ratio is adjusted.

The distribution means 5 is provided with a control circuit 16 and a driving device 17 as shown in FIG. 1, so that the distribution ratio of the distribution means 5 is automatically adjusted by the power consumption of the drive motor 18 of the vertical roller mill 3. It is also possible to control the amount of circulation by controlling automatically. In this way, by changing the distribution ratio of the distribution means 5 by the power consumption of the vertical roller mill 3, the circulation amount is adjusted even when the operating state of the vertical roller mill 3 changes in response to changes in the properties of the material to be ground. By doing so, the power consumption of the vertical roller mill 3 can be made constant at all times. As a result, the operating state of the vertical roller mill 3 can always be kept constant or can be effectively maintained with the motor power usage capacity being full, so that optimum crushing efficiency and maximum crushing capacity can always be exhibited.

In the above embodiment, since the remaining portion of the crushed product distributed by the distributing means 5 and returned to the vertical roller mill 3 is supplied to the sieving means 8, the sieving means 8 screens the remaining crushed product. It is sufficient if it has the ability, and it can be made much smaller than the sieving means used in the conventional sieving and circulating apparatus.

Further, as shown in FIG. 3, even if the sieving means 8 is positioned at the upper stage and the distributing means 5 is positioned at the lower stage in series with this, the sieving means cannot be downsized,
The effect of remarkably reducing the vibration and reducing the size of the crushed product in the secondary crushing step can be obtained as in the above-described embodiment.

In the above embodiment, the bucket elevator 12 and the separator 13 are used after the secondary crushing step, but other structures may be used instead of this structure.

Further, in the above-mentioned embodiment, the distribution damper having the distribution blades 5a is used as an example of the distribution means 5 and the bucket elevator 4 is used as the transportation means, but any structure having an equivalent function may be used.

[0035]

According to the present invention, since the bulk specific gravity of the object to be crushed and crushed by being caught between the table and the roller in the vertical roller mill can be increased, the following effects can be obtained.

Vibrations peculiar to the vertical roller mill can be remarkably reduced, and the structural members of the vertical roller mill can be made lighter.

Further, as a result of the vibration being reduced, the pressing force of the roller can be set to a higher pressing force with the best crushing efficiency without being restricted by the vibration.

Further, the circulation amount to the vertical roller mill can be adjusted by the distribution means, and the crushing device can be stably operated under the optimum crushing efficiency condition of the vertical roller mill.

Further, due to the effect of arranging the distributing means and the sieving means in series, coarse products having a certain value or more in the crushed products for the secondary crushing process can be removed. In particular, when the distributing means is arranged in the upper stage, the sieving means can be significantly downsized.

In particular, according to the crushing apparatus of the fourth aspect, since only the fine particles under the sieve are put into the tube mill, the balls of the tube mill can be excluded from the large diameter balls, and the diameter can be greatly reduced. It is possible to improve the grinding efficiency of the tube mill.

[Brief description of drawings]

FIG. 1 is a systematic diagram of an entire crushing device showing an embodiment of the present invention.

FIG. 2 is a sectional view of a distribution means.

FIG. 3 is a systematic diagram of the entire crushing device showing another embodiment of the present invention.

FIG. 4 is a system diagram showing an entire prior art crushing device.

FIG. 5 is a schematic view for explaining a crushing mechanism.

FIG. 6 is a system diagram showing another whole crushing device of the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed quantity supply machine 2 ... Fixed quantity supply machine 3 ... Vertical roller mill 3a ... Table 3b ... Roller 4 ... Bucket elevator 5 ... Distributing means 6, 7 ... Chute 8 ... Sieving means 9, 10 ... Chute 11 ... Tube mill 12 ... Bucket Elevator 13 ... Separator 14, 15 ... Chute 16 ... Control circuit 17 ... Drive device

Claims (4)

(57) [Claims] 1. A vertical roller mill for pressing a roller onto a table to crush an object to be ground, and a vertical roller mill for grinding.
In a pulverizing device using a vertical mill in which a sieving means for sieving the pulverized product is arranged in series, a part of the pulverized product pulverized by the vertical roller mill is used as it is.
Distributing means for returning to the vertical roller mill in the state of
A control circuit that controls the distribution ratio of
The layer thickness displacement of the material to be crushed into the Lamill should be reduced.
Milling device according to vertical mill, wherein the door. 2. Between the vertical roller mill and the sieving means,
Part of the crushed product crushed by a vertical roller mill
Distributing means for returning to the vertical roller mill in the state
Use sieving means for crushed products other than those returned to the vertical roller mill with
The vertical mill according to claim 1, wherein the vertical mill is supplied.
Crusher 3. A sieving machine, which has been screened by sieving means,
Return to the die roller mill and place it downstream of the sieving means.
A part of the sieve that has been screened
-Charge characterized by providing a distribution means for returning to Ramil
Item 1. A crushing device using a vertical mill according to item 1. 4. The bottom of the sieve which is sieved by sieving means
A claim characterized in that a tube mill for subsequent crushing is provided
Item 2. A pulverizer using the vertical mill according to item 2 or item 3.