JP2594829B2 - Centrifugal flow crusher - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crusher. More specifically, the present invention relates to a centrifugal fluidized pulverizing apparatus having an outer peripheral ring and a rotating dish, in which a pulverizing medium such as a steel ball accommodated in the apparatus is centrifugally fluidized to pulverize a raw material.

[Prior art] There are various types of pulverizers such as a tube mill and a vertical mill. A rotating plate is installed upward and the rotating plate is rotated to remove steel balls or the like housed inside. There is known a so-called vertical ball mill in which a pulverizing medium (hereinafter, referred to as a ball) is circulated to grind and grind a raw material.

FIG. 3 (a) is a schematic sectional view showing an example of the configuration of a conventional vertical ball mill. Reference numeral 1 denotes a rotating plate, whose rotation axis is installed in a vertical direction, and is rotatable around this axis by a drive shaft 2. The rotating plate 1 has a substantially flat bottom surface B and an inclined side surface A whose diameter increases upward. Reference numeral 3 denotes a fixed cover, which has a ring shape, and has an inner surface having a semicircular cross-sectional shape. In the conventional device shown in FIG. 3 (a), the ball crawls from the bottom surface B along the side surface A with the rotation of the rotating plate 1, moves to the center side along the lower surface of the fixed cover 3, and then is fixed. It separates from the cover 3 and falls on the bottom surface B.

FIG. 3 (b) is a schematic sectional view showing another example of the configuration of a conventional vertical ball mill. In the conventional example of FIG. 3B, the rotating plate 4 has a conical portion 5 at the center thereof, and the ball detached from the lower surface of the fixed cover 3 is attached to the side surface C of the conical portion 5. After hitting, the bottom B of the rotating plate 4
To fall.

[Problems to be Solved by the Invention] In a vertical ball mill as shown in FIG. 3, a grinding operation is mainly performed by sliding between the side surfaces A of the rotating plates 1, 4 and the balls, that is, a so-called grinding system. In this sliding, the speed difference between the vertical sliding in which the ball crawls on the side surface A and the circumferential speed of the ball on the rotating plate side A in the circumferential direction around the rotating plate 1 or the four axis is determined. There are two types of sliding caused.

In conventional vertical ball mills, rotating plates
Since the side surfaces A of 1, 4 also form a part of the rotating plate 4, the side surfaces A rotate in the same circumferential direction as the ball. Therefore, the circumferential rotation speed between the side surface A and the ball is not so high, and the crushing and grinding action resulting from this circumferential speed difference is weak.

In addition, a centrifugal force is applied to the ball by the rotation of the rotating plates 1 and 4, and the ball crawls up the side surface A by this centrifugal force to obtain potential energy. However, in the conventional example of FIG. 3, the potential energy obtained by this ball is
When the ball separates from the lower surface of the fixed cover 3 and falls and hits the bottom surface B, almost all of the ball is consumed and cannot be used for the crushing and grinding operations. In the case of the conventional device shown in FIG. 3B, the ball falling from the lower surface of the fixed cover 3 is bounced off the side surface C of the conical portion 5 and a radial force is applied to the ball. Are converted to velocity energy and can be used for grinding and grinding operations. However, since the ball is bounced off the side surface C, the energy loss due to the collision becomes considerably large.

As described above, in a conventional grinding apparatus generally called a vertical ball mill, the grinding and grinding actions are weak, or the energy input to the apparatus is easily consumed in addition to the grinding and grinding actions, and the energy efficiency is low. There was a problem.

In addition, in the conventional example shown in FIG. 3, since a classifier is not attached to the pulverizer, it is not possible to freely select and take out the required product fineness (fineness), and continuous operation cannot be performed. Since the operation was forced, there were problems such as poor production efficiency.

[Means for Solving the Problems] In order to solve the above problems, the centrifugal flow crushing device of the present invention has a conical shape in which the rotation axis is arranged in a vertical direction and the diameter increases downward. At the same time, it has a rising portion that expands upward near the outer peripheral end, and has a rotating plate that is rotated by the driving device, and a ring shape that contracts upward, so as to surround the outer periphery of the rotating plate. An outer peripheral ring which is provided coaxially with the rotating dish and is driven to rotate stationary or in the opposite direction to the rotating dish, and a grinding medium accommodated in a grinding chamber surrounded by the outer peripheral ring and the rotating dish. The vertical cross-sectional shape of the plate surface of the rotating plate and the inner wall surface of the outer peripheral ring are each concavely curved, and the plate surface and the inner wall surface form a continuous smooth surface. A suction outlet at the top of the grinding chamber In the centrifugal fluidized crusher provided with a classifier at the lower part of the discharge port, the classifier has a pair of upper and lower rotating disks and a blade interposed between outer edges of the rotating disks, And a central portion between the two rotating disks is provided with an opening communicating with the discharge port, and a lower portion of the classifier is sandwiched between a pair of upper and lower rotating disks and an outer edge portion of the rotating disk. And a circulation fan having blades having a propulsive force to the airflow, and a guide passage for reversing the airflow direction at an outer peripheral portion between the classifier and the circulation fan.

[Operation] In the centrifugal fluidized crusher of the present invention, since the outer surface of the crushing chamber is a fixed surface or a counter-rotating surface, the circumferential speed difference between the ball and the side surface is increased, and the crushing and grinding in the side surface portion are performed. The attrition effect is significantly increased.

Also, since the ball migrates along the surface of the rotating dish,
The potential energy obtained when the ball crawls on the side wall can be efficiently converted into velocity energy, and the loss of the energy input to the apparatus is extremely small.

In addition, in the centrifugal flow pulverizer of the present invention, a circulation fan is provided below the classifier, and a guideway is provided between the classifier and the circulation fan for reversing the airflow entering the classifier, and the classification is performed by the classifier. Since the crushing is performed, the classification efficiency is high, and the crushing efficiency is improved without over-crushing. In addition, since it has a built-in classifier, it has a compact configuration.

For this reason, according to the present invention, various substances such as slag, Portland cement clinker, limestone, coal, mica (mica), and ceramics such as alumina can be efficiently pulverized.

Embodiment An embodiment will be described below with reference to the drawings.

First, the basic configuration of the centrifugal fluid crusher (particularly, crushing chamber X) and its operation will be described.

FIG. 2 is a cross-sectional view showing an example of a basic centrifugal flow pulverizer. Reference numeral 6 denotes a rotating plate, the rotation axis of which is set in a vertical direction, and a liner 6a is attached to the plate surface. The rotating plate 6 has a conical shape whose diameter increases downward. The rotating plate 6 is driven to rotate by the drive shaft 3.

Reference numeral 5 denotes an outer peripheral ring, which is provided coaxially with the rotating plate 6 so as to surround the outer periphery of the rotating plate 6. The outer peripheral ring 5 has a shape whose diameter is reduced upward, and the lower part of the outer peripheral ring 5 and the outer peripheral edge of the rotating plate 6 are slidably in contact with each other. In addition, as shown in FIG.
Between the outer peripheral edge of the rising portion and the minimum ball diameter, for example.
A slight gap of about 10 to 30% may be provided.

The plate surface D of the rotating plate 6, the rising portion E, and the inner wall surface F of the outer peripheral ring 5 are all formed in a concavely curved vertical cross section,
The contact portion between the plate surface D and the rising portion E also forms a smoothly continuous surface.

Next, the operation of the centrifugal flow pulverizer will be described.

The balls are accommodated in a grinding chamber surrounded by the rotating plate 6 and the outer peripheral ring 5, the raw material to be ground is charged, and the rotating plate 6 is rotated via the drive shaft 3. Then, the ball is moved in the outer peripheral direction by the centrifugal force, and is crawled up on the inner wall surface F of the outer peripheral ring 5 by this velocity energy.
And land on the surface D of the rotating plate 6. The ball that has moved onto the plate surface D rolls down and rises along the plate surface D,
Further, it is moved toward the outer peripheral ring 5 again by the centrifugal force given by the rotation of the rotating plate 6.

When the rotating plate 6 is rotated, the ball revolves in the circumferential direction at a speed lower than the rotating speed of the rotating plate 6. Therefore, in addition to the vertical elliptical motion circulating through the plate surface D, the rising portion E and the inner wall surface F as described above, the ball also performs a revolving motion rotating around the axis of the rotating plate 6. Performs a spiral movement that twists the rope that combines the two movements. (Note that the movement of the ball is referred to as centrifugal pulse flow in this specification.) As described above, the ball moves on the inner wall surface F while maintaining the movement in the circumferential direction of the rotating plate 6. However, when the inner wall surface F is fixed, the composite speed of the circumferential speed (revolution speed) of the ball and the crawling up speed of the ball becomes the speed difference between the inner wall surface F and the ball.
When the inner wall surface F is rotating in the reverse direction, the speed difference is further increased. Therefore, the speed difference between the ball and the inner wall surface F becomes extremely large, and the action of crushing and grinding the ball when moving on the inner wall surface F becomes extremely strong.

Further, the ball that has detached from the inner wall surface F and has landed on the dish surface D is subjected to centrifugal force by the rotating dish surface D and moves toward a rising portion near the outer peripheral end. Furthermore, the potential energy obtained when running up the inner wall surface F can be converted into kinetic energy in the radial direction by the movement of the plate surface D and the rising portion E during the electrophoretic descent and ascent. The applied energy can be effectively used for the pulverizing and grinding operations without unnecessarily consuming the applied energy. When the ball descends along the dish surface D, the ball
Therefore, the raw material is crushed even during this downward movement.

In such a centrifugal fluidized-pulverizer, the rotation speed of the rotating plate may be constant, but may be changed regularly or irregularly. By varying the number of revolutions, irregular movement of the ball is provided, and the grinding action is improved.

FIGS. 4A to 4E are schematic diagrams illustrating a temporal pattern of the rotation speed N of the rotating plate. In FIG. 4A, the rotating plate is rotated at a constant speed. In (b), the rotation speed fluctuates to a smooth waveform such as a sine curve. In (c), after rotating at a constant speed (high speed) for a predetermined time, the speed is reduced to a constant speed lower than that, and after rotating for a predetermined time in this low speed state, the speed is returned to the high speed again. repeat. In (d), the number of revolutions fluctuates according to the sawtooth waveform. (E)
In, the same waveform is repeated by changing the sawtooth waveform to gradually reach the maximum rotation speed, and thereafter to rapidly reduce the speed.

FIG. 1 is a cross-sectional view showing an example of the overall configuration of the apparatus when the apparatus of the present invention is actually operated.

Reference numeral 15 denotes a casing that covers the main body of the crusher, and the outer peripheral ring 5 is attached to the inner surface of the casing 15 via a connecting member (not shown). Reference numeral 4 denotes a pillar, which pivotally supports the rotating plate 6 via a bearing 3a. The rotating shaft 3 is connected to a driving device such as the electric motor 1 via the speed reducer 2.

At the center of the ceiling of the classifier casing 8 connected to the casing 7, a feed pipe 11 for the raw material is provided, and a duct 12 is provided so as to surround the feed pipe 11, and the rotary cylinder 10 is connected to the duct 12. Have been.

In the present embodiment, the outer peripheral ring 5 is lined with a liner 5a, and is provided with a number of slits or small holes 5b so as to penetrate the wall surface. A side cover 16 is provided between the bottom of the outer surface of the outer peripheral ring 5 and the inner surface of the casing 15,
An air introduction chamber 17 is formed between the side cover 16 and the casing 15 and the outer surface of the outer peripheral ring 5 so that air can be introduced from an air introduction pipe 18. The upper end of the side cover 16 is sealed to the outer surface of the side of the outer peripheral ring 5.

On the other hand, a clearance 19 of 10 to 30% of the minimum ball diameter is provided between the outer peripheral edge of the rotating plate 6 and the inner peripheral edge of the bottom of the outer peripheral ring 5.

The bottom cover 20 inside the air introduction chamber 17 is connected to a pipe 21 for extracting and transporting the powder and granules, and the pipe 21 is disposed so that the powder and granules can be returned to the input pipe 12. I have. In addition, a scraper 22 is fixed below the outer peripheral edge of the rotating plate 6, and is configured to collect powder particles falling into the bottom cover 20 toward a connection portion of the extraction pipe 21. I have.

A cover 28 is provided so as to cover the upper surface of the casing 8. The rotary cylinder 10 is inserted into the center of the top of the lid 28, and is pivotally supported by a bearing 29. The rotating cylinder 10 includes, for example, a pulley 29a and a belt 29b.
Drive device (not shown) by appropriate power transmission means such as
It is connected to the. The upper end of the rotary cylinder 10 and the duct
The lower end of 12 is rotatably connected by a connection mechanism, for example, a rotary joint. Reference numeral 13 denotes an outlet connected to the duct 12.

The classifier 30 is connected to the lower end of the rotary cylinder 10. In the present embodiment, the classifier 30 includes a pair of upper and lower rotating disks 30a and 30b, and a blade 30 sandwiched between edges of the disks 30a and 30b.
c, and an opening 30d.

In addition, immediately below the classifier 30, a rotating shaft 4d that rotates coaxially with the rotating cylinder 10 coaxially with the rotating cylinder 10 that is the rotating shaft of the classifier 30.
There is a circulation fan 40 having a pair of upper and lower rotating discs 40a,
A blade 40c is sandwiched between outer edges of the rotating disk 40a and the rotating disks 40a, 40b, and has a downward airflow propulsion force. Also, the upper rotating disk 40a has a circular opening 40e on the inner diameter side, and the lower rotating disk 40b has an opening 40f on the outer diameter side,
Each of them forms an air flow passage.

Further, a pair of upper and lower conical guide cones 50a and 50b are formed on an outer peripheral portion between the classifier 30 and the circulation fan 40 so as to form a guide path 50 for reversing the direction of the introduced airflow. , And is fixed to the circulation fan 40.

The rotating shaft 40d of the circulation fan 40 is supported by a bearing 40g disposed on the lower rotating disk 30b of the classifier 30.

The outlet 13 is connected to a suction blower (not shown) via a powder collecting means such as a bag filter.

The operation of the device of the present invention configured as described above will be described.

In the crushing device thus configured, the raw material is charged into the crushing chamber X from the charging pipe 11. On the other hand, with the rotation of the rotating plate 6, the ball moves in the crushing chamber X in an elliptical motion circulating between the lining 5a of the outer peripheral ring 5 and the plate surface 6a,
The spiral motion is performed by twisting the rope with the revolving motion around the axis of the material, and the raw material is pulverized in the meantime. Also,
The air introduced from the air introduction pipe 18 into the air introduction chamber 17 and the bottom cover 20 flows into the grinding chamber X through the clearance 19 and the slit (or small hole) 5b, and accompanies the powder generated by the grinding. Reached the classifier 30 and received the classification action,
The coarse fraction is returned to the grinding chamber X again, and the fine fraction is sent to the collection means via the rotary cylinder 10, the duct 12, and the discharge port 13, and collected by the collection machine.

Next, the functions of the classifier 30 and the circulation fan 40 will be described. The fine particles pulverized to a predetermined particle size in the pulverizing section are conveyed to the above-described air flow of the clearance 19 or the slit 5b, and rise up along the inner surface of the casing 7. Guide cone 50a,
It flows into the guideway 50 formed by 50b. The dust-containing airflow that has flowed into the guide path 50 is fed to the rotating classifier 30 and the circulation fan 4.
The particles are branched by the suction force of 0, and the relatively coarse particles among the fine particles contained in the air flow go straight as they are,
Is returned to the crushing chamber X through the openings 40e and 40f. On the other hand, the relatively fine particles are inverted and the blades 30c of the classifier 30
Classifier 30 easily accompanies the airflow heading toward, and passes through to the outlet 13. The fine particles splashed by the blades 30 c by this classification action go to the circulation fan 40.

Therefore, the fine particles having a certain degree of spread in the product fineness (finesse) conveyed by airflow from the crushing chamber X are:
When the guide cone is inverted, it undergoes a first-order classification operation (inertial classification), and then undergoes a second-order classification operation (centrifugal classification) by rotation of the classifier blades. As a result, when it is desired to obtain a product in the ultra-fine pulverization region, for example, submicron particles, it is usual that the output is very small relative to the input and the classification efficiency is low. In the classifier of the present invention, 1
Because of the subsequent classification, the ratio of flouring to flouring can be significantly improved. For example, in the case of the present embodiment, the downward airflow velocity in the guideway is set to 30 to 50 m / sec, and the guideway airflow 6
Against 0 m ³ / min, ejection amount 50 m ³ / min of circulation fan, to design a classifier introducing air volume 10 m ³ / min, new air flowing into the grinding apparatus requires only 10 m ³ / min, air volume per product The number of classification opportunities is increased by 6 times compared to the model that introduces 60m ³ / min directly to the classifier.

In addition, since the circulation fan 40 is set so that the direction of jet of the airflow is directed downward, relatively coarse particles that cannot be obtained as a final product can be immediately returned to the grinding chamber, so that the grinding efficiency is improved. In addition, the airflow ejected downward from the circulation fan transports the fine particles to the crushing chamber, and then comes into contact with the crushing chamber and reverses, so that new crushed fine particles in the crushing chamber are guided in the classifier direction, that is, accurately guided. Since the circulating airflow serves as a carrier that conveys the air to the path 50, the energy for air conveyance is saved. Therefore, the new air introduced into the machine from the clearance 19 and the slit 5b is
Since it requires only 10 m ³ / min against the amount of circulating air 50 m ³ / min, can be significantly reduced.

In addition, the ultrafine powder of 0.1 to 3 μm causes agglomeration in units of several tens, and apparently becomes coarse particles of several μm to several tens of μm. When this occurs, the powder is crushed, so that the reduction of the agglomerated particles and the discharge of the ultrafine particles from the present apparatus are promoted, and the over-crushing is prevented.

As described above, the airflow containing fines particles of the final product passing through the classifier 30 goes to the discharge port 13 as described above.

Note that by making the number of revolutions of the classifier and the number of revolutions of the circulating fan variable, the fineness of the product and the amount of circulating air can be arbitrarily set or changed. That is, the classification point is controlled by the number of revolutions of the classifier, and the amount of circulating air in the pulverizer is controlled by the number of revolutions of the circulation fan.

The particles that have escaped from the crushing chamber through the slits (or small holes) 5b or the clearances 19 are returned to the crushing chamber by the conduit 21 and the charging pipe 11.

This pulverizing device is 200 to 3 depending on the properties of the raw material to be pulverized.
Rotated at 000rpm. Further, the ball preferably has a diameter of about 3 to 70 mm.

Since this device is equipped with a classifier, continuous operation is basically used normally, but batch operation for testing is also possible.

Further, in the present embodiment, the outer peripheral ring is of a fixed type, but the outer peripheral ring may be driven to rotate in a direction opposite to the direction of the rotating plate.

[Effects of the Invention] The centrifugal fluidized crusher of the present invention has the following features as compared with other types of crushers.

That is, in a horizontal pulverizer such as a ball mill, when the number of rotations increases, the pulverizing medium rotates around the inner surface of the body. Further, in an attritor or a tower mill, because of the mechanism, the stirring rod or the rotating blade is rotated so as to push the balls apart, so that the resistance becomes too large and the rotation cannot be performed at a too high rotation speed. In contrast, in a centrifugal fluidized-pulverizer, the relative speed between the rotor (rotating dish) and the stator (outer peripheral ring) can be increased theoretically without limit. Of course, it is meaningless to increase the rotation more than a certain degree due to technical or economic restrictions, but the limit speed is much larger than that of the above-mentioned ball mill, attritor and tower mill. For this reason, a ball movement like a rope can be adopted at a high speed, which is a feature of the apparatus of the present invention.
Very advantageous for the attrition action.

Further, in the centrifugal fluidized pulverizer, the speed difference between the inner wall surface of the outer peripheral ring and the ball is large, and the pulverizing action is excellent.

In addition, since the centrifugal flow pulverizer of the present invention has a guide path formed by a classifier, a circulation fan, and a guide cone, a product having a sharp particle size distribution with almost no coarse powder falling can be obtained.

Since continuous operation is possible, production efficiency is improved.

Ultrafine powder can be classified efficiently.

The grinding efficiency is improved and over-grinding is prevented.

The amount of carrier air introduced into the crusher can be greatly reduced.

And other excellent effects.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a centrifugal flow pulverizer according to an embodiment of the present invention, FIG.
4 (a) and 4 (b) are schematic cross-sectional views showing the configuration of a conventional pulverizer, and FIGS. 4 (a) to 4 (e) are explanatory views of the rotating speed of a rotating dish. 5 ... outer peripheral ring, 6 ... rotating plate, 7 ... casing, 8 ... casing of classifier, 10 ... rotating cylinder, 11 ... material supply pipe, 12 ... duct, 13 ... outlet, 29 …… Bearing, 30… Classifier, 30a, 30b …… Rotating disk, 30c …… Blade, 30d …… Opening, 40 …… Circulation fan, 40a, 40b …… Rotating disk, 40c …… Blade 40d ... rotating shaft, 40e ... opening, 40f ... opening, 40g ... bearing, 50 ... guideway, 50a, 50b ... guide cone, D ... plate surface (rotary plate), E ... Rising part (rotating plate), F: inner wall surface (outer ring), X: crushing chamber.

Claims (1)

(57) [Claims] 1. A driving device, wherein a rotation axis is disposed in a vertical direction, has a conical shape expanding in diameter downward, and has a rising portion expanding in diameter upward near an outer peripheral end thereof. A rotating plate that is rotated by the rotating plate, and has a ring shape whose diameter is reduced upward, is coaxially provided with the rotating plate so as to surround the outer periphery of the rotating plate, and is stationary or in a direction opposite to the rotating plate. An outer peripheral ring that is driven to rotate, and a grinding medium housed in a grinding chamber surrounded by the outer peripheral ring and the rotating plate. The vertical cross-sectional shapes of the plate surface of the rotating plate and the inner wall surface of the outer peripheral ring are each concave. A centrifugal flow crushing device having a curved surface and a continuous smooth surface between the plate surface and the inner wall surface, and a suction / discharge port provided at an upper portion of the crushing chamber; In a centrifugal flow crusher equipped with a classifier at the bottom of the outlet, The classifier has a pair of upper and lower rotating disks and a blade interposed between outer edges of the rotating disks, and an opening in which a central portion between the two rotating disks communicates with the discharge port. A circulating fan having a pair of upper and lower rotating disks and blades sandwiched between outer edges of the rotating disks and having a propulsion force to an air flow below the classifier; A centrifugal flow pulverizer, comprising a guide passage whose airflow direction is reversed in an outer peripheral portion between the machine and the circulation fan.