JPH11347430A - Pulverizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable operation of a pulverizer and also to contrive miniaturizing and energy saving of the pulverizer by optimizing particle diameters of raw material fed into a vertical roller mill and a tube mill. SOLUTION: In a vertical roller mill 1 in which the considerable amount of pulverized raw material is taken out from below the mill, raw material of relatively small particle diameters is taken out from above the mill together with gas introduced into the mill to reduce fine particles to be caught in a pulverizing part. And the raw material taken from the mill 1 is sorted and separated into coarse powder, middle powder, and fine powder by a classifier 2. The fine powder is made a product, all or part of the coarse powder is returned to the vertical roller mill to pulverize it again, and also the middle powder or the middle powder and remaining part of the coarse powder sorted by a distributing means is subjected to secondary pulverization by a tube mill, thereby optimizing particle diameters of the raw material fed into the pulverizers. Furthermore hot gas is used as the gas to dry the raw material while it is pulverized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulverizing apparatus for efficiently pulverizing raw materials such as cement raw materials, cement clinker, coal, limestone, slag, ceramics, fillers and chemicals into products having a predetermined particle size. , Especially raw materials,
The present invention relates to a pulverizing apparatus suitable for pulverizing by two-stage pulverization using a vertical roller mill and a tube mill.

[0002]

2. Description of the Related Art Conventionally, a vertical roller mill or a tube mill has been used for pulverizing raw materials such as cement raw materials, cement clinker, coal, limestone, and slag. However, in recent years, from the viewpoint of energy saving,
A vertical roller mill with high coarse crushing efficiency as a primary crusher,
Raw material is coarsely pulverized (hereinafter sometimes referred to as primary pulverization).
After that, a two-stage pulverizing apparatus in which the coarsely pulverized raw material is finely pulverized as a secondary pulverizer by a tube mill having a high fine pulverization efficiency (hereinafter sometimes referred to as secondary pulverization) is becoming mainstream.

A vertical roller mill used as a primary pulverizer of such a two-stage pulverizer is disclosed in
As shown in FIG. 1 of Japanese Patent Publication No. 200047, most of the pulverized raw material is dropped from the outer peripheral surface of the pulverizing table and the inner peripheral surface of the casing to the outside of the mill, taken out, and mechanically transported by a bucket elevator or the like. A vertical roller mill (also referred to as a mill lower take-out type) of a type that is transported to a classifier by a mill, or the entire amount of milled raw material is transferred between a milling table and a case as shown in FIG. From the top of the mill device by blowing it up with the gas introduced into the mill and taking out the gas together with the gas. In FIG. 6 of the publication, the dust is separated by the dust collector and the classifier twice to remove the fine powder. (They serve as a classifier that sorts and separates coarse particles.)
There is. In FIG. 1 of the publication, the raw material taken out from below the mill is separated into fine powder (raw material reduced to the product particle size) and coarse particles by a classifier. And the whole amount of coarse particles is sent to a tube mill of a secondary pulverizer to be subjected to secondary pulverization. Also,
In FIG. 6 of the official gazette, the raw material taken out together with the gas from above the mill is separated into fine powder and coarse particles by being classified twice by a dust collector and a classifier, and the fine powder is used as a product. While being taken out, the whole amount of coarse particles is sent to a tube mill of a secondary pulverizer for secondary pulverization.

[0004] The two-stage pulverizing process in the case of using a vertical roller mill of a lower take-out type will be described with reference to FIG. The raw material is transported from the raw material hopper to a vertical roller mill, and the raw material is charged into the vertical roller mill. The input raw material is pulverized by a vertical roller mill. A small amount (about 2 to 5% of the input raw material) of the pulverized raw material for dust collection in the apparatus is taken out from above the mill as fine powder, but other raw materials (substantially, Is almost the total amount of input raw materials)
Is dropped to the outside below the mill from between the outer peripheral surface of the grinding table and the inner peripheral surface of the casing, and is taken out of the mill as a primary pulverized product.

[0005] The primary pulverized product is conveyed by a bucket elevator or the like and introduced into a classifier, where it is classified, and coarse particles (sometimes called coarse powder) and fine powder (also fine powder). Is separated from the classification device. Then, the fine powder is sent to a collector as it is, where it is collected, taken out as a product, and the coarse particles taken out from the classification device are sent to a tube mill, where they are subjected to secondary pulverization. Then, the raw material secondary pulverized by the tube mill is transported by a bucket elevator or the like and sent to a classification device, where it is classified again, or
It is taken out as it is as a product. Generally, such a vertical roller mill of the lower take-out type sucks a small amount of air in the mill to remove a small amount of the mill (2 to 2 of the input raw materials).
So-called atmospheric dust is collected by collecting fine powder (about 5%) and extracting it from above the mill.

The classifying apparatus shown in FIG. 1 of this publication takes out a raw material which has been reduced to the particle size of the product as fine powder, and sets a classification point so that raw materials other than the fine powder can be taken out as coarse particles. Is set.

[0007]

SUMMARY OF THE INVENTION However, in the first publication of the publication,
In a crusher using a vertical roller mill as a primary crusher in a crusher for performing two-stage crushing as shown in the figure, almost all of coarse particles, which are crushed products of a vertical roller mill, are taken out of the mill and a bucket elevator. To be transported to the classifier by
Although there is an advantage that the conveying power can be reduced as compared with the case where the whole amount of coarse particles of the pulverized product is conveyed by air, it has the following problems. When using a vertical roller mill of a mill lower take-out type as a primary crusher, the raw material that is crushed by being crushed by the crushing table and the crushing roller in the vertical roller mill is formed on the outer circumferential surface of the crushing table and the inner circumferential surface of the casing. Between the outside and the outside of the mill, and
The powder stays on the table in the mill and is pulverized again.
As described above, some of the raw materials that remain in the mill or are supplied to the mill have a small particle size that is not necessary to be coarsely pulverized and should be subjected to secondary pulverization, or a small material that can be used as a product as it is. A raw material having a particle size is also included, and pulverizing such a raw material with a vertical roller mill deteriorates the pulverizing efficiency of the vertical roller mill, and also causes problems such as excessive pulverization of the raw material.

Further, the vertical roller mill has a characteristic that vibration is apt to occur when the amount of fine powder in the raw material caught between the crushing table and the crushing roller is large. In the dust, the raw material having a small particle diameter that is largely contained in the staying raw material cannot be sufficiently removed, and the fine powder caught between the crushing table and the crushing roller increases, so that the vertical roller mill is likely to generate vibration. There is a problem.

[0009] When a vertical roller mill of the type taken out of the mill as shown in Fig. 6 of the publication is used as the primary pulverizer, most of the fine powder contained in the raw material is blown into the mill. Since the gas is blown up above the mill together with the gas and taken out from above the mill apparatus, the vibration caused by the biting is rarely a problem, but the wind pressure balance may be lost and vibration may occur. Also, a large gas flow rate and pressure are required to blow up the whole amount of the pulverized raw material with the gas introduced into the mill and to remove the raw material from above the mill device. In particular, when using a vertical roller mill of this type as a primary pulverizer, it is necessary to blow up a material having a relatively large particle size with gas and remove it from above the mill, which requires a very large air volume and pressure. , Large air carrying energy is needed. Therefore, as compared with the vertical roller mill of the mill lower take-out type, the power consumption of the mill becomes worse, and the power consumption of the whole crushing device also becomes worse.

On the other hand, the classifier used for the pulverizer for performing the two-stage pulverization has the following problems. For example, when a classifier is used with a flow sheet as shown in FIG. 1 of the publication, the classifier classifies the input raw material into only fine powder and coarse powder, so that the total amount of coarse powder is reduced. It will be sent to a tube mill. However, since the raw material that is primarily pulverized by the vertical roller mill and fed into the classifier contains many raw materials having a large particle size that should be coarsely pulverized,
A large amount of raw material having a large particle size, which should be roughly pulverized, is contained in the coarse powder charged into the tube mill. As a result, the efficiency of the secondary pulverization is deteriorated, which is a factor that hinders downsizing of the apparatus.

Although FIG. 1 of the above publication shows an example of a mill lower take-out type, a pulverizer using a vertical roller mill of a mill upper take-out type as shown in FIG. In the pulverized raw material, a raw material having a large particle size that is better to be coarsely pulverized is included, so if the above-described classification is performed and the two-stage pulverization is performed, a similar problem occurs. .

[0012] As described above, in the classifier as described above, since the input raw material can be roughly divided into only coarse powder and fine powder, the particle size of the raw material input to the vertical roller mill and the tube mill can be reduced. It is difficult to optimize the diameter, and these problems reduce the efficiency of the apparatus and hinder miniaturization of the apparatus.

[0013]

In order to solve the above-mentioned problems, a pulverizing apparatus according to the present invention comprises: (1) a pulverizing table which rotates horizontally in a casing, and a pulverizing roller which rotates by being pressed against the upper surface of the pulverizing table. Crushing the raw material supplied on the crushing table between
A considerable amount of the supplied raw material is dropped from the outer peripheral surface of the pulverizing table and the inner peripheral surface of the casing to the outside of the mill to be taken out, and is also removed from the outer peripheral surface of the pulverizing table and the inner peripheral surface of the casing into the mill. A vertical type in which a gas is introduced into the feedstock and / or a raw material having a relatively small particle size in the pulverized raw material, and the remaining amount of the raw material to be taken out from below the mill is taken out from above the mill together with the gas. A roller mill and a material having a relatively small particle diameter taken out together with the gas from the vertical roller mill and a material dropped to the outside below the mill and taken out of the mill are fed, and coarse powder, medium powder, and fine powder are supplied. Classifying equipment that separates and sorts fine powder, a collector that collects the fine powder that has been separated and separated by the classifying equipment and turns it into a product as it is, and crushes all or part of the coarse powder that has been separated and separated by the classifying equipment again The vertical row And distribution means for returning to the mill, was constructed by.

(2) In the pulverizer of the above (1),
The amount of the raw material having a relatively small particle diameter to be taken out from the upper side of the mill is 10 to 30% in proportion to the amount of the raw material put into the vertical roller mill. The amount of the raw material is configured to be 90 to 70% in proportion to the amount of the raw material charged into the vertical roller mill.

(3) In the pulverizer according to the above (1) or (2), the gas introduced into the vertical roller mill is a hot gas.

(4) The above (1) or (2) or (3)
In the pulverizing device, the middle powder sorted and separated by the classification equipment, or the remaining portion of the coarse powder sorted by the distribution means and the middle powder, a tube mill is supplied,
Secondary grinding is performed by the tube mill.

(5) In the pulverizer of the above (4),
The tube mill separates and separates product particles and other coarse particles, and the coarse particles are returned to the tube mill. The first classifying equipment, and the fine particles transported by gas flow through the tube mill are fed. The product particles and other coarse particles are separated and separated, and the product particles are fed to the collector for the vertical roller mill, and the coarse particles are fed to the first classification equipment. The configuration includes a second classification facility.

(6) In the pulverizer of the above (5),
The gas passed through the tube mill is a hot gas.

[0019]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 5 show an embodiment according to the present invention.
FIG. 2 is a flow sheet of the crushing device according to the first embodiment, FIG. 2 is a vertical sectional view of a vertical roller mill according to the crushing device of the first embodiment, and FIG. FIG. 4 is a vertical sectional view, FIG. 4 is a conceptual diagram of the behavior of the powder of the classification device according to the pulverizing device of the first embodiment, and FIG. 5 is a flow sheet of the pulverizing device according to the second embodiment.

A pulverizer according to a first embodiment of the present invention will be described with reference to FIGS. Raw material hopper 60
The raw material supplied to the vertical roller mill 1 (in this embodiment,
The raw material input port 35 of the vertical roller mill 1
The raw material is fed into the central portion of the crushing table 32 from above the crushing table 32 through a raw material charging chute 37 provided at the upper center of the crushing table 32. The input raw material is rotated on the crushing table 32, and is moved to the outer peripheral portion of the crushing table 32 while drawing a spiral trajectory on the crushing table 32 by the generation of centrifugal force due to the rotation. It is bitten by the table 32 and the crushing roller 31 and crushed.

The raw material that has been bitten by the crushing table 32 and the crushing roller 31 reaches the outer edge of the crushing table 32, and a dam ring 38 is fixedly provided on the outer rim of the crushing table 32. Therefore, the raw material reaching the outer edge of the crushing table 32 is dammed by a dam ring 38 provided around the outer edge of the crushing table 32,
The powder is retained on the crushing table 32 while maintaining a predetermined layer thickness, and is crushed by being crushed by the crushing table 32 and the crushing roller 31.

The raw material having passed over the dam ring 38 is discharged into an annular passage DF between the outer peripheral surface of the crushing table 32 and the inner peripheral surface of the casing. Flows upward in the mill from an annular passage DF between the outer peripheral surface of the crushing table 32 and the inner peripheral surface of the casing, and has a relatively small particle size in the raw material discharged into the annular passage DF. The raw material is carried upward in the mill by the hot gas stream, and is taken out together with the hot gas from the upper outlet 39 of the vertical roller mill 1. Further, the raw material having a relatively small particle diameter contained in the raw material and floating on the table in the mill is carried upward in the mill by the flow of hot gas, and is taken out from the upper outlet of the vertical roller mill 1. It is taken out together with the hot gas from 39. In the apparatus of this embodiment, the raw material is dried with a hot gas to remove moisture contained in the raw material.

The raw material discharged into the annular passage DF and having a large particle size which cannot be lifted by the hot gas flow is supplied to the annular passage DF between the outer peripheral surface of the grinding table 32 and the inner peripheral surface of the casing. It is dropped further to the outside below the mill and taken out from the lower outlet 34 to the outside of the mill.

In the present embodiment, if the amount of the raw material having a relatively small particle diameter taken out together with the hot gas from the upper outlet 39 of the vertical roller mill 1 is too large, the flow rate and pressure of the hot gas become large, and the gas is conveyed. As a result, the power loss of the fan increases, and the power consumption decreases. On the other hand, if the amount is too small, excessive pulverization of the raw material and vibration of the vertical roller mill are likely to occur, and the pulverization efficiency deteriorates.

Therefore, in the present invention, the amount of the raw material having a relatively small particle diameter to be taken out together with the gas from above the vertical roller mill 1 is set to 10 to 30% of the amount of the raw material supplied to the mill 1.
By taking out a considerable amount of 90 to 70% from the lower portion of the mill, the above problem can be solved. That is, by adjusting the flow rate of the hot gas, 1/10 to 1/1 / of the conventional vertical roller mill of the upper take-out type.
3, the amount of the raw material having a relatively small particle diameter taken out together with the hot gas from the upper outlet 39 of the vertical roller mill 1 is set to 10% to 30% with respect to the input raw material, and the flow rate and wind pressure of the carrier gas are adjusted appropriately. By keeping the blower power of the exhaust fan 9 at an appropriate small power while keeping the value small, over-pulverization by the vertical roller mill 1 and vibration of the mill 1 can be effectively suppressed. More preferably, when the content is set to 15 to 20%, it is possible to more appropriately and stably prevent the mill from being excessively pulverized and vibrated with the blowing power of the appropriate fan and the small transporting power of the mechanical conveyor.

If the amount of the raw material having a relatively small particle size taken out together with the hot gas is smaller than 10% of the input raw material, it becomes impossible to suppress overmilling by the mill 1 and vibration of the mill 1, and If the ratio is larger than 30%, the air volume and wind pressure of the hot gas increase, the pressure loss due to gas conveyance increases, the power of the fan increases, and the power consumption decreases. Therefore, in this embodiment, the vertical roller mill is used. The amount of the raw material having a relatively small particle diameter taken out together with the hot gas from the upper outlet 39 of the first raw material is 10% to 30% with respect to the input raw material.
It is preferable that

The raw materials taken out from the vertical roller mill 1 are as follows:
It is put into the classification device 2 shown in FIG. At this time, the raw material taken out from the upper outlet 39 of the vertical roller mill 1 is sent to the classification device 2 through the classification gas introduction pipe 15 together with the hot gas, and is taken out from the lower outlet 34 of the vertical roller mill 1. The raw material is conveyed through a bucket elevator 41 or the like and is charged into the raw material charging port 17a of the classification device 2. The input raw material is classified by a classifier 2 (the structure and operation of the classifier 2 will be described later in detail), and separated and separated as coarse powder, medium powder and fine powder of the primary pulverized product. Then, the fine powder is fed together with the gas to the cyclone type collector 43, where it is collected into a product. In addition, the medium powder is fed to a tube mill 10, where it is secondarily pulverized.

In this embodiment, a raw material having a particle size of about 0.1 mm or less as a fine powder of the primary pulverized product, a raw material having a particle size of about 1 to 5 mm as a medium powder of the primary pulverized product, and a coarse powder of the primary pulverized product The raw material having a particle size of 5 to 10 mm was separated and sorted. However, it is needless to say that the particle diameters of the coarse powder, the medium powder, and the fine powder need to be appropriately changed according to the particle diameter of the product, the crushing ability of the tube mill, and the like.

The coarse powder is conveyed to a distributor 55. The distributor 55 converts the raw material flowing from the classification device 2 into
It has a structure that can be distributed and sent to two lines, and the distribution ratio can be arbitrarily switched. Therefore, the coarse powder can be distributed in an arbitrary amount and distributed to two lines, or the whole amount of the raw material can be flowed to one of the lines. Of the two lines mentioned above,
One line is connected to the raw material input port 35 of the vertical roller mill 1, and the other line is connected to the raw material input port of the tube mill 10.

The coarse powder sent to the distributor 55 is returned to the vertical roller mill 1 for re-grinding, or
The coarse powder is distributed by the distributor 55, distributed to two lines, sent to the vertical roller mill 1 and the tube mill 10, and pulverized by the respective pulverizers.

Originally, it is more efficient to grind the entire amount of the coarse powder of the primary pulverized product with the vertical roller mill 1, in which case it is not necessary to sort the coarse powder into two lines by the distributor 55, but the raw material is In the case of raw materials that are difficult to pulverize, the amount of coarse powder increases, and when the entire amount of coarse powder is returned to the vertical roller mill, the processing capacity of the vertical roller mill may be exceeded. A part of the coarse powder was distributed to a tube mill and distributed in accordance with the above. Also in the present embodiment, the distributor 55 is switched only when necessary and the minimum amount is distributed to the tube mill 10 in consideration of the pulverizability of the raw material, the processing capability of the vertical roller mill 1, and the processing capability of the tube mill 10. I have to. This enables a highly efficient operation of the pulverizer.

The raw material pulverized and taken out by the tube mill 10 is sent to a classification device 51 via a bucket elevator 42 or the like and classified, and has a predetermined particle size equal to or less than a predetermined value which becomes a product as a secondary pulverized product fine powder. Only product particles from the collector 43
To be collected and collected. Classifier 51
The coarse particles, which are the remaining raw materials that have not been fed to the collector 43 after being classified, are taken out from the classification device 51 as coarse powder of the secondary pulverized product, returned to the tube mill again and pulverized again.

At this time, a hot gas is blown into the tube mill in order to remove the fine particles in the mill, and the fine particles in the tube mill are conveyed by the flow of the hot gas and extracted from the tube mill. . However, the raw material taken out by the gas flow contains not only fine particles but also a small amount of a raw material having a large particle diameter. Therefore, the taken out raw material is fed to the classification device 52 and classified. .
Then, the product particles are taken out as fine powder in the gas supplied from the tube mill and sent to the collector 43 where they are collected to become a product. Further, the coarse powder in the gas supplied from the tube mill is classified by the classifier 52 and collected by the collector 4.
The coarse particles not fed to 3 are taken out and returned to the tube mill again to be pulverized. In this embodiment, the coarse particles which have been classified by the classifying device 52 and not sent to the collector 43 are classified again by the classifying device 51 and fed into the tube mill for the convenience of material transportation. The coarse particles classified into 52 and not sent to the collector 43 may be directly returned to the tube mill and pulverized.

In this embodiment, as the raw material,
Since the cement raw material was used, the raw material was simultaneously dried using hot gas.However, when it is not necessary to dry the raw material, use air as the gas for the vertical roller mill, tube mill, classifier, etc. Of course, it is good.

The details of the classifier 2 applied to the pulverizer of the first embodiment will be described below with reference to FIGS.
The classifier 2 in the present embodiment is surrounded by an inner casing composed of an outer casing composed of an upper casing 11 and a side casing 12 and a lower casing 13. The upper casing 11 has a substantially cylindrical shape, has a fine powder outlet 20 on a side surface portion, and a raw material inlet 17a and a variable speed motor 30 are provided on the upper surface. I have.

The upper portion of the upper casing 11 is sealed by a top plate so as not to leak the classification gas (hot gas in this embodiment) and the raw material.
The bearing case 7 including the shaft 6 and the shaft 6 penetrates the top plate and is inserted into the upper casing 11. The bearing case 7 is fixed to the upper casing 11 and the raw material charging chute 17 and extends in the vertical direction of the raw material charging chute 17. It is located on the center line of. A rotatable shaft 6 rotatably supported by a bearing 7 a is inserted through the bearing case 7, and the shaft 6 connects the electric motor 30 and the dispersion plate 3. The raw material inlet 17a, the shaft 6, and the bearing case 7 are sealed so that the classification gas and the raw material blown into the upper casing 11 do not leak.

The material input chute 17 has a substantially inverted frustoconical hopper shape in the upper casing 11 and has a diameter which is increased upward, and has two material input ports 17a at the upper portion. , The lower part is cylindrical, and the disk 4
Inserted in the center of the

Next, the side casing 12 has a substantially cylindrical shape, and its diameter is increased upward.
It is attached to the lower casing integrally with the upper casing.
The lower bottom portion of the side casing 12 is inclined toward the lower middle powder outlet 21, and the raw material entering the lower bottom portion of the side casing 12 naturally flows to the middle powder outlet 21 by gravity. It has a structure to go.

The lower casing 13 has a substantially cylindrical shape.
The upper part expands in diameter upward, and is inserted and arranged concentrically inside the side casing 12. The upper end of the lower casing 13 is open, and a cylindrical collision plate 13a is provided. Further, since the cylindrical collision plate 13a is replaceably attached to the inner peripheral surface of the upper end portion of the lower casing 13, the collision plate 13a has a structure that can be replaced according to wear. And
A lower portion of the lower casing 13 has a coarse powder outlet 22.

The lower part of the upper casing 11 and the upper part of the side casing 12 are fixed via a substantially annular plate.
It is sealed so that the raw material and the classification gas do not leak. Further, the inner wall surface of the side casing 12 and the lower casing 13
An annular passage DT for taking out the middle powder is formed between the outer wall surface and the upper end of the annular passage DT, which opens in the side casing to form a middle opening DK for taking the middle powder. I have. The classified raw material has a structure capable of falling through the annular opening DK for taking in the middle powder through the annular passage DT and moving to the outlet 21 for taking the middle powder. The lower end of the side casing 12 is fixed to the outer wall of the lower casing 13 via a substantially annular plate, and is sealed so that the raw material and the classification gas do not leak.

In the upper part of the lower casing 13, a disk-shaped dispersion plate 3 integrally attached to the rotary shaft 6 at a substantially central position at a height substantially equal to that of the cylindrical collision plate 13a is rotatable. , The dispersion plate 3 and the collision plate 1
A classifying gas blow-up annular passage DS is formed between the passage 3a. The raw material discharged from the dispersion plate 3 into the annular passage DS and the raw material colliding with the collision plate 13a are separated into coarse powder and smaller powder by the classification gas blown up the annular passage DS. The dispersion plate 3, the collision plate 13a, and the annular passage DS constitute a primary classifier 8.

Further, at the height position of the upper end of the cylindrical collision plate 13a above the dispersion plate 3, a plurality of columns 4a fixed to the upper part of the center of the dispersion plate 3 are fixed. A ring-shaped disk 4 is rotatably mounted with the same axis of rotation as the dispersion plate 3, and on the outer periphery of the disk 4, classification blades 5 a are positioned inside the upper casing 11 at intervals. There are provided a plurality of sheets. In other words, the classifying blades 5a have their lower ends attached to the outer peripheral edge of the disk 4 and their upper ends inclined to be positioned outside the disk, and the upper end is close to the upper casing so that the raw material does not short-pass. It has such a structure.

There is a gap between the classifying blades 5a and the circumferential direction of the classifying blades 5a, through which the classifying gas and the fine powder can pass during operation. Dispersion plate 3 is upper casing 11
Since the motor 30 is connected via the shaft 6 to the motor 30 fixed to the motor, the motor 30 can be rotated by the rotation of the motor 30.
Further, since the classifying blades 5a are connected to the dispersion plate 3 via the columns 4a and the disks 4, the classifying blades 5a can be simultaneously rotated by the electric motor 30. In addition, the disk 4 and the classifying blades 5
“a” constitutes a secondary classification unit 5 that classifies the classification gas that has passed upward through the primary classification unit 8 and classifies the classified gas into fine powder and medium powder.

The annular opening DK for taking in the intermediate powder is formed so as to be opened substantially facing the lower part radially outward of the classifying blade 5a, and is opened and struck by the rotation of the classifying blade 5a. The middle powder blown radially outward collides with the inner wall of the upper casing 11, stalls, and is taken into the annular opening DK as it is.

The raw material charging chute 17 fixed to the upper casing 11 is provided at the center of the disk 4 of the secondary classification section 5.
The insertion hole at the lower end of the material input chute 17 of the disk 4 is dust-sealed so as to be able to rotate and slide with respect to the lower end of the material input chute 17. The raw material on the dispersion plate 3 and the classifying gas passing through the classifying gas blow-up annular passage DS may be separated from the classifying blades 5a of the secondary classifying section 5 except for the circumferential gap between the classifying blades 5a (for example, the central portion of the disk 4). And the upper casing 11 cannot be moved into the upper casing 11 through a hole or a gap between the secondary classifying section 5 and the upper casing 11).

In the lower casing 13, a classification gas introduction pipe 15 having a classification gas introduction port 15 a whose tip is open upward at a position below the classification gas blow-up annular passage DS.
Is inserted, and between the position just below the dispersion plate 3 and the classifying gas introduction port 15a, a substantially inverted truncated cone-shaped guide cone 16 forms a part of the inverted cone portion at the lower end thereof. It has a shape inserted through the center of the classifying gas inlet 15a, and is fixed to the lower casing via a support (not shown). Therefore, the classifying gas blown into the classifying device 2 from the classifying gas introduction pipe 15 by the action of the guide cone 16 can be rectified and uniformly flow in the circumferential direction of the classifying gas blow-up annular passage DS.

Next, the operation of the classifier configured as described above will be described mainly with reference to FIGS. First, the primary pulverized by the vertical roller mill 1
The raw material taken out from the lower outlet 34 of
a, and passes through the raw material charging chute 17 and falls near the center of the dispersion plate 3. Also, a vertical roller mill 1
The raw material taken out together with the gas from the upper outlet 39 is introduced into the classification device 2 through the classification gas introduction pipe 15. The raw material dropped on the dispersion plate 3 is the dispersion plate 3
The raw material that has fallen is also rotated by the dispersion plate 3
It starts to rotate following the rotation of. Therefore, a centrifugal force is generated in the raw material due to rotation, and the raw material moves in the outer peripheral direction of the dispersion plate 3 and then jumps out of the dispersion plate 3 in the direction of the collision plate 13a.

The raw material that has flown out of the dispersion plate 3 is supplied to the classifying gas blow-up annular passage DS between the dispersion plate 3 and the collision plate 13a.
And is thrown out into the annular passage DS, or collides with the collision plate 13a and is thrown out into the annular passage DS. At this time, in the annular passage DS, the classification gas blown from the classification gas inlet 15a through the classification gas introduction pipe 15 passes through the space between the guide cone 16 and the lower casing 13 to form a uniform circumferential flow from below. Is being blown up. In this embodiment, since the hot gas from the upper outlet 39 of the vertical roller mill 1 is used as the classifying gas blown from the classifying gas inlet 15a, the comparison gas extracted from the upper outlet 39 together with the hot gas is used. A raw material having an extremely small particle size (about 2 mm or less in this embodiment) is fed into the classification device 2.

The raw material having a large particle size is blown up by the classification gas blown out from the classification gas inlet 15a, but the raw material (coarse powder) having a large particle size is not blown up but falls as it is. The raw material with a large particle size that has dropped
The coarse powder of the primary pulverized product passes through the annular passage DS and further passes through the annular passage DV between the lower casing 13 and the classification gas inlet 15a of the classification gas introduction pipe 15 and the coarse powder outlet 22 at the lower end of the lower casing 13. Is taken out as

The classifying gas blown out from the classifying gas inlet 15a is rectified by the guide cone 16, and the classifying gas can be blown up evenly in the entire annular passage DS. Classification is performed.

Further, the raw material blown up by the classification gas in the primary classification section 8 and the relatively small particle size fed into the classification device 2 by the classification gas blown from the classification gas inlet 15a (in this embodiment, Is approximately 2
mm or less) reaches the upper secondary classification section 5, where it is further classified, and the raw material having a small particle size (fine powder)
The primary pulverized product passes through the circumferential gap between the classifying blades 5a of the secondary classifying section 5 that is rotating only and reaches the upper casing 11 and is accompanied by the classifying gas from the fine powder outlet 20 via the classifying gas. Extracted as fine powder. Then, the other raw materials (medium powder) are knocked down by the classifying blades 5a of the rotating secondary classifying unit 5 and fall through the secondary classifying unit 5 without being able to pass through.

At this time, since the classification gas is blown up from below, the intermediate powder falls while moving outward in the radial direction of the secondary classification unit 5, so that it falls near the inner wall surface of the side casing 12 or Alternatively, it collides with the inner wall surface of the side casing 12 and stalls, and falls along the inner wall surface of the side casing 12. Accordingly, the intermediate powder enters the annular opening DK for intake of the intermediate powder, which is exposed to the lower periphery in the radial direction of the classifying blade 5a as it is, and enters the annular passage DT between the side casing 12 and the lower casing 13. Through the medium powder outlet 2
It is taken out as a medium powder of the primary pulverized product from 1.

Also, as in the case of the primary classification, the classification gas blown out from the classification gas inlet 15a is rectified by the guide cone 16, and the classification gas is uniformly blown up to the entire annular passage DT. In any case, a uniform flow of the classification gas occurs in any part of the secondary classification section downstream of the primary classification section, and as a result, uniform secondary classification is performed.

In this embodiment, the casing of the classification device is constructed by inserting the lower casing 13 through the side casing 12 and the inside thereof, so that the side casing 12 and the lower casing 13 are used to take in the medium powder. An annular opening DK, an intermediate passage DT communicating with the annular opening DT, and
The intermediate powder outlet 21 can be formed by itself, and the coarse powder outlet 22 can be formed at the lower end of the lower casing 13, so that the classifier can be simply configured.

In this embodiment, the dispersion plate 3 of the primary classifying section 8 and the classifying blades 5a of the secondary classifying section 5 are connected to the same drive shaft and driven to rotate simultaneously by the motor 30 of the same drive source. This simplifies the configuration of the classification device and ensures that the dispersion plate 3 and the classification blade 5a are rotationally driven.

As described above, in the classifying apparatus 2 of this embodiment, the raw material can be efficiently classified into fine powder, medium powder and coarse powder of the primary pulverized product.

Since a hot gas is used as the gas blown from the classification gas introduction port 15a, the raw material can be classified and dried at the same time. Particularly, fine powder having a large specific surface area has good drying efficiency and no drying equipment is required. It is.

In this embodiment, the raw material having a particle size of about 0.1 mm or less as the fine powder of the primary pulverized product, the raw material having the particle size of about 1 to 5 mm as the medium powder of the primary pulverized product, and the coarse powder of the primary pulverized product The raw material having a particle size of 5 to 10 mm was separated and classified, and this value can be changed depending on the rotation speed of the secondary classification unit 5 and the like. Therefore, it is necessary to appropriately change the value according to the type of the product and the process. Can be.

In this embodiment, the classification blade 5a
Is fixed to the dispersing plate 3 with the support 4a and the disk 4 interposed therebetween and is rotatably arranged integrally with the dispersing plate 3. However, it is rotatable by directly attaching to the shaft 6 via a support, a bracket or the like. May be arranged.

In this embodiment, the case where the dispersion plate 3 of the primary classifying section 8 and the classifying blades 5a of the secondary classifying section 5 are connected to the same drive shaft 6 to be driven to rotate is shown. However, it is needless to say that the dispersion plate 3 and the classification blades 5a are mounted on separate drive shafts, and the motors are separately connected to the respective drive shafts so that the dispersion plate 8 and the classification blades 5a are individually driven to rotate. Is also good. In the case of such a configuration, the primary classifying unit and the secondary classifying unit can be independently controlled to control the classifying performance, and the classification can be performed with higher accuracy.

In the above embodiment, the motor for driving the dispersion plate 3 and the classifying blades 5a is the motor 30, but the motor may be a hydraulic motor or the like.

The cylindrical collision plate 13a is
Although the case where the upper end of the lower casing 3 is replaceably attached to the inner peripheral surface of the lower casing 3 so as to be replaceable in accordance with wear is shown, it may be connected to the upper end of the lower casing 13.

In the case of the first embodiment using the classifier 2 having the above configuration and features, one classifier can be used.
Since it can be classified into three types, primary powder, coarse powder, medium powder, and fine powder, the powder can be sent to the next process that is optimal for each particle size with simple equipment, improving the efficiency of grinding. Can be.

In the second embodiment according to the present invention, a general classifier capable of separating and separating powder only into coarse powder and fine powder, which has different classification points, for example, as shown in FIG. By using a combination of two as in the flow sheet shown in (1), a method is used in which the raw material supplied from the vertical roller mill 1 is separated into coarse powder, medium powder and fine powder of the primary pulverized product. . (The classifier 2a is the classifier 2b
The classification point is set to a smaller particle size. The powder after classification is handled in the same manner as in the first embodiment.

In the above embodiment, the case where the cement raw material is pulverized has been described. However, when the pulverizing apparatus of the present invention is used, not only the cement raw material but also cement clinker, coal, limestone, slag, ceramics, filler, chemical And the like can be efficiently pulverized into a product having a predetermined particle size according to the above principle.

[0066]

As described above, in the pulverizer according to the present invention, in claim 1, the gas volume and the air pressure of the carrier gas are adjusted so that the raw material having a relatively small particle size can be increased in the gas volume and the air pressure of the carrier gas. In a proper range, the material is lifted by gas and taken out from the upper part of the mill, and a considerable amount of material other than the material having a relatively small particle size taken out from the upper part of the mill is taken out from the lower part of the vertical roller mill and lifted. By transporting to a classifier using a mechanical conveyor with low transport power, the exhaust fan's blowing power is kept at an appropriate low level,
It is possible to effectively suppress overmilling and vibration of the vertical roller mill while suppressing the gas pressure loss and maintaining an appropriate power consumption unit. In addition, the raw material before pulverization or the raw material with a relatively small particle size that does not need to be coarsely pulverized and is contained in the pulverized raw material that is bitten by the pulverizing table and the pulverizing roller is moved upward with the gas together with the gas. By blowing it up and removing it from above the mill device, the amount of raw material to be pulverized by the vertical roller mill can be reduced. In addition, the raw material taken out from the vertical roller mill is separated and separated into coarse powder, medium powder, and fine powder by a classifier, so that only the raw material that has been reduced to the product particle size is collected as fine powder in the collector. The powder can be sent as it is, and the product can be used as it is. In addition, the coarse powder mainly has a large particle diameter, and the particle diameter of the coarse powder to be pulverized again by the vertical roller mill can be optimized. Further, since the means for returning the coarse powder to the vertical roller mill has a distribution function, the amount of the raw material to be ground again by the vertical roller mill can be adjusted. The efficiency of the pulverizer can be improved by changing it according to the capacity of the pulverizer, the pulverizability of the raw material, and the like.

In the present invention, the amount of gas and the pressure of the gas are adjusted so that the amount of the raw material having a relatively small particle diameter taken out from above the vertical roller mill is made to be a ratio to the amount of the raw material charged into the vertical roller mill. By setting the content to 10 to 30%, it is possible to more appropriately and stably prevent overmilling and vibration of the mill with the blowing power of the appropriate fan and the small transporting power of the mechanical conveyor.

According to the third aspect of the present invention, the gas to be introduced into the vertical roller mill is a hot gas, so that the raw material can be dried and simultaneously crushed and classified in the vertical roller mill.

According to the fourth aspect, the raw material from which the raw material which has already become the product particle size and which does not need to be subjected to secondary pulverization is removed is sent to the tube mill and pulverized, thereby preventing the raw material from being excessively pulverized in the tube mill. In addition, if the raw material having a large particle diameter is pulverized by a tube mill, the efficiency is low. However, in the case of the pulverizing apparatus of claim 4, the amount of the raw material having a large particle diameter (coarse powder) to be fed into the tube mill is minimized or The optimal particle size (medium powder) for the tube mill is increased as the raw material to be put into the tube mill while being suppressed to zero, so that efficient secondary pulverization can be performed, the efficiency of the tube mill is improved, and the equipment is downsized. And energy savings.

According to the fifth aspect, the fine particles in the tube mill are taken out together with the gas to prevent the raw material from being excessively pulverized by the tube mill. In addition, the first and second classifiers can separate the raw material taken out of the tube mill into product particles and other coarse particles, thereby collecting the product particles to obtain a product, By returning the coarse particles to the tube mill and grinding again,
A pulverizer with high pulverization efficiency can be obtained.

According to the sixth aspect of the present invention, the raw material can be dried in the tube mill by using hot gas as the gas passing through the tube mill.
It is possible to prevent the fine powder from adhering to the eyeboard or the like.

[Brief description of the drawings]

FIG. 1 is a flow sheet of a crusher according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a vertical roller mill according to the crushing apparatus of the first embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a classification device according to the pulverizing device of the first embodiment of the present invention.

FIG. 4 is a conceptual diagram of the behavior of the powder during operation of the classification device according to the pulverizing device of the first embodiment of the present invention.

FIG. 5 is a flow sheet of a crusher according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical roller mill 2 Classifier 10 Tube mill 17 Raw material input chute 17a Raw material input port 31 Pulverizing roller 32 Crushing table 33 Gas inlet 34 Lower outlet 35 Raw material inlet 39 Upper outlet 43 Collector 51 Classifier 52 Classifier 52 Classifier 55 Distributor DF Annular passage

Claims (6)

[Claims] A raw material supplied onto the grinding table is crushed between a crushing table that rotates horizontally in a casing and a crushing roller that is pressed against and rotates on the upper surface of the crushing table. Of the milling material is dropped from the outer peripheral surface of the crushing table and the inner peripheral surface of the casing to the lower side of the mill and taken out, and gas is introduced into the mill from the outer peripheral surface of the crushing table and the inner peripheral surface of the casing and supplied. A vertical roller mill, which is a raw material having a relatively small particle diameter in the raw material and / or the pulverized raw material, the remaining amount of which is taken out from below the mill together with the gas is taken out from above the mill; Classification where the raw material with a relatively small particle size taken out together with the gas from the roller mill and the raw material dropped to the outside of the mill and taken out of the mill are fed and separated into coarse powder, medium powder and fine powder. Equipment, a collector for collecting the fine powder separated and separated by the classifying equipment to produce a product as it is, and a vertical apparatus for re-grinding all or a part of the coarse powder separated and separated by the classifying equipment. Distributing means for returning to the mold roller mill;
A crushing device characterized by comprising: 2. The amount of the raw material having a relatively small particle diameter taken out from above the mill is 10 to 30% in proportion to the amount of the raw material charged into the vertical roller mill,
2. The crusher according to claim 1, wherein the amount of the raw material dropped and taken out of the lower portion of the mill is 90 to 70% in proportion to the amount of the raw material charged into the vertical roller mill. 3. The crusher according to claim 1, wherein the gas introduced into the vertical roller mill is a hot gas. 4. A tube mill to which the middle powder separated and separated by the classification equipment or the remaining part of the coarse powder sorted by the distribution means is supplied. 4. The pulverizing device according to claim 1, wherein the pulverizing is performed next. 5. The tube mill is a first classifier for selectively separating and separating product particles and other coarse particles, and the coarse particles are returned to the tube mill. The tube mill is conveyed by gas flow through the tube mill. Fine particles are fed and separated and separated into product particles and other coarse particles, and the product particles are fed to the collector for the vertical roller mill, and the coarse particles are fed to the first classification equipment. 5. The apparatus according to claim 4, further comprising a second classifying device configured to perform the classification.
A crushing device as described. 6. The pulverizer according to claim 5, wherein the gas passed through the tube mill is a hot gas.