JPH02265659A - Centrifugal fluid milling equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a crushing device. More specifically, the present invention relates to a centrifugal fluid pulverizer which is equipped with an outer ring and a rotating plate and which pulverizes raw materials by centrifugally flowing a pulverizing medium such as steel balls housed inside the device.

[Prior Art] There are various types of crushing devices such as tube mills and vertical mills, but by installing a rotating plate facing upward and rotating this rotating plate, the steel balls etc. housed inside are crushed. 2. Description of the Related Art A so-called vertical ball mill is known in which a grinding medium (hereinafter referred to as a pole) is circulated to grind and grind raw materials.

FIG. 3(a) is a schematic cross-sectional view showing an example of the configuration of a conventional vertical ball mill. Reference numeral 1 denotes a rotating plate, and the rotation axis of the rotating plate 1 is installed in the vertical direction and is rotatable around this axis by a drive shaft 2. Slanted side surface A that expands in diameter
It is equipped with Reference numeral 3 denotes a fixed cover, which is ring-shaped and whose inner surface has a semicircular cross-section.

In the conventional device shown in FIG. 3(a), the pole climbs up the side surface A from the bottom surface B as the rotary plate l rotates, then moves toward the center along the lower surface of the fixed cover 3, and then is fixed. It separates from the cover 3 and falls onto the bottom surface B.

FIG. 3(b) is a schematic cross-sectional view showing another example of the structure of a conventional vertical ball mill. In the conventional example shown in FIG. 3(b), the rotary plate 4 has a conical portion 5 at its center, and the pole detached from the lower surface of the fixed cover 3 is attached to the side surface C of the conical portion 5. After being hit, it falls onto the bottom surface B of the rotating plate 4.

[Problem B to be solved by the invention] In a vertical ball mill as shown in FIG. 3, the grinding action is mainly carried out by sliding between the side surface A of the rotary plate 1.4 and the pole, which is a so-called grinding method. . This sliding includes the vertical sliding of the pole as it climbs up the side surface A, and the speed difference between the circumferential speed of the rotating plate side surface A and the circumferential speed of the pole around the rotating plate 1 or 4 axis. There are two types of sliding caused by

However, in the conventional vertical ball mill, the rotary plate 1
．． Since side A of 4 also forms part of rotating plate 4, side A rotates in the same circumferential direction as the pole. Therefore, the rotational speed in the circumferential direction between the side surface A and the pole is not so large, and the crushing and grinding effects caused by this circumferential speed difference are weak.

Furthermore, centrifugal force is applied to the pole by the rotation of the rotary plates 1 and 4, and the pole crawls up the side surface A due to this centrifugal force, thereby gaining potential energy.

However, in the conventional example shown in FIG.
When it falls off and hits the bottom surface B, almost all of it is consumed and cannot be used for crushing or grinding. In the conventional device shown in Fig. 3(b), the fixed cover
3. The pole falling from the bottom surface is bounced off the side surface C of the conical part 5 and a radial force is applied to the pole, so some of the potential energy obtained by the pole is converted into velocity energy and causes crushing and grinding action. It is said that it can be used for. However, since the pole is bounced off the side C, the energy loss due to the collision is quite large.

In this way, conventional grinding devices commonly known as vertical ball mills have weak grinding and grinding effects, or the energy input into the device is easily consumed for purposes other than grinding and grinding, resulting in low energy efficiency. There was a problem.

In addition, in the conventional example shown in Figure 3, a classifier is not attached to the crusher, so it is not possible to freely select and take out the required product fineness, and continuous operation is not possible. This left problems such as low production efficiency as the machines were forced to operate.

[Means for Solving the Problems] In order to solve the above problems, the centrifugal fluid pulverizer of the present invention has a rotating shaft center installed in the vertical direction, and has a conical shape whose diameter expands downward. At the same time, the rotary plate has a rising portion whose diameter expands upward near the outer peripheral end and is rotated by a drive device, and an annular shape whose diameter decreases upward and surrounds the outer periphery of the rotary plate. The grinding medium comprises: an outer ring disposed coaxially around the rotating plate and stationary or rotationally driven in the opposite direction to the rotating plate; and a grinding medium housed in a grinding chamber surrounded by the outer ring and the rotating plate. The vertical cross-sectional shapes of the dish surface of the rotary dish and the inner wall surface of the outer circumferential ring are respectively concavely curved shapes, and the dish surface and the inner wall surface form a continuous smooth surface. A crushing device,
Further, in the centrifugal fluid crushing apparatus in which a suction discharge port is provided in the upper part of the crushing chamber and a classifier is provided in the lower part of the discharge port, the classifier includes a pair of upper and lower rotating disks and an outer edge of the rotating disks. and a central portion between the two rotating disks has an opening that communicates with the discharge port.

A circulation fan is provided below the classifier, and includes a pair of upper and lower rotating disks and blades that are sandwiched between the outer edges of the rotating disks and have a propulsive force for downward airflow. The configuration includes a guide passage in which the direction of air flow is reversed on the outer periphery between the fans.

[Function] In the centrifugal fluid milling device of the present invention, the outer surface of the milling chamber is a fixed surface or a counter-rotating surface.

The circumferential velocity difference between the pole and the side surface increases, and the crushing and grinding action in this side surface portion becomes significantly large.

In addition, since the pole migrates along the surface of the rotating plate, the potential energy obtained when the pole climbs up the side wall can be efficiently converted into velocity energy, and the loss of energy input into the device is extremely reduced. few.

In addition, in the centrifugal fluid pulverizer of the present invention, a circulation fan is provided below the classifier, and a guide path is provided between the classifier and the circulation fan to reverse the airflow entering the classifier, and the classifier performs classification. Since the pulverization is performed while the pulverization is performed, the classification efficiency is high, and there is no over-pulverization, which improves the pulverization efficiency. Also, since it has a built-in classifier, it has a compact configuration.

Therefore, according to the present invention, ceramics such as slag, Bortland cement clinker 1 limestone, coal, mica, and alumina are used.

It can efficiently crush various substances.

[Example] Examples will be described below with reference to the drawings.

First, the basic configuration of the centrifugal fluid pulverizer (especially the pulverizer
) and its operation.

FIG. 2 is a sectional view showing an example of a basic centrifugal fluid pulverizer. Reference numeral 6 denotes a rotating plate, the rotating shaft of which is installed in the vertical direction, and a liner 6a attached to the surface of the plate. The rotary plate 6 has a conical shape whose diameter increases downward. This rotary plate 6 is rotationally driven by the drive shaft 3.

Reference numeral 5 denotes an outer circumferential ring, which is disposed coaxially with the rotating plate 6 so as to surround the outer periphery of the rotating plate 6. The outer circumferential ring 5 has a diameter that decreases upward, and the lower part of the outer circumferential ring 5 and the outer circumferential edge of the rotary plate 6 are in slidable contact with each other. Note that, as shown in FIG.
A slight gap of about 0 to 30% may be provided.

The countersunk surface of the rotary plate 6, the rising portion E, and the inner wall surface F of the outer circumferential ring 5 all have a concavely curved vertical cross-sectional shape, and the contact portion between the countersunk surface and the rising portion E is also smooth. It forms a continuous surface.

Next, the operation of the centrifugal fluid pulverizer will be explained.

A pole is housed in a grinding chamber surrounded by a rotary plate 6 and an outer ring 5, and the raw material to be crushed is introduced into the grinding chamber, and the rotary plate 6 is rotated via a drive shaft 3. Then, the pole is moved in the outer circumferential direction by centrifugal force, and by this velocity energy it crawls up the inner wall surface F of the outer ring 5, and then leaves the inner wall surface F and lands on the countersunk surface of the rotary plate 6. The pole that has moved onto the surface moves down and rises along this surface, and is again moved toward the outer ring 5 by the centrifugal force exerted by the rotation of the rotary plate 6.

Further, when the rotary plate 6 is rotated, the poles revolve in the circumferential direction at a speed slower than the rotational speed of the rotary plate 6. Therefore, in addition to the above-mentioned elliptical movement in the vertical direction that circulates between the plate surface, the rising portion E, and the inner wall surface F, the pole also performs a revolving movement that rotates around the axis of the rotary plate 6, and these movements Performs a spiral motion that combines two motions, as if pulling on a rope.

(This movement of the pole is referred to as centrifugal pulsating flow in this specification.) In this way, the pole performs a movement of creeping up on the inner wall surface F while maintaining the movement in the circumferential direction of the rotary plate 6. However, when this inner wall surface F is fixed, the composite speed of the circumferential velocity (revolution speed) of the pole and the crawling speed of the pole becomes the speed difference between the inner wall surface F and the pole. Further, when the inner wall surface F is rotating in the opposite direction, the speed difference becomes even larger. Therefore, the speed difference between the pole and the inner wall surface F becomes extremely large, and the crushing and grinding action of the pole when moving on the inner wall surface F becomes extremely strong.

Furthermore, the pole that has separated from the inner wall surface F and landed on the countersunk surface is subjected to centrifugal force by the rotating countersunk surface, and moves toward a rising portion near the outer peripheral end.

The potential energy obtained when moving up and down the inner wall surface F can be converted into kinetic energy in the radial direction by the motion of migrating down and up the countersunk surface and the rising part E, so it is once applied to the pole. The generated energy can be effectively used for crushing and grinding without wasting it.

Furthermore, when descending along the countersunk surface, the pole slides on the countersunk surface, so that the raw material is ground even during this downward movement.

Note that in such a centrifugal fluid pulverizer, the rotational speed of the rotary plate may be constant, but may be varied regularly or irregularly. By varying the rotational speed, irregularities are imparted to the movement of the poles and the grinding action is improved.

FIGS. 4(a) to 4(e) are schematic diagrams illustrating patterns over time of the number of rotations N of the rotary plate. In FIG. 4(a), the rotating plate is rotated at a constant speed. In (b), the rotational speed fluctuates in a smooth waveform such as a sine curve.

In (C), after rotating at a constant speed (high speed) for a predetermined time, it is decelerated to a lower constant speed, and after rotating at this low speed for a predetermined time, it is returned to high speed again. turn green again. In (d), the rotational speed varies according to a sawtooth waveform. Also, in (e), the sawtooth waveform is changed to gradually reach the maximum rotational speed, and thereafter the same waveform is repeated with rapid deceleration.

FIG. 1 is a sectional view showing an example of the overall configuration of the device according to the present invention when the device is actually operated.

Reference numeral 15 denotes a casing that covers the main body of the crusher, and the outer ring 5 is attached to the inner surface of the casing 15 via a connecting member (not shown). Reference numeral 4 denotes a pedestal, and a 0-rotation shaft 3 that pivotally supports a rotating plate 6 via a bearing 3a is connected to a driving device such as an electric motor 1 via a reduction gear &'12.

A raw material input pipe 11 is installed in the center of the ceiling of the classifier casing 8 connected to the casing 7, and a duct 12 is provided to surround this input pipe 11, and a rotary cylinder lO is connected to this duct 12. has been done.

In this embodiment, the outer circumferential ring 5 is lined with a liner 5a, and a large number of slits or small holes 5b are bored through the wall surface thereof. A side cover 16 is provided between the bottom of the outer surface of the outer ring 5 and the inner surface of the casing 15, and an air introduction chamber 17 is defined between the side cover 16, the casing 15, and the outer surface of the outer ring 5. And air is introduced! Air can be introduced from 1'1-18.

Note that the upper end of the side cover 16 is sealed to the outer side surface of the outer circumferential ring 5.

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

A conduit 21 for extracting and transporting powder and granules is connected to the bottom cover 20 inside the air introduction chamber 17, and this conduit 21 is arranged to be able to return the powder and granules to the input pipe 12. ing. Further, a scraper 22 is fixedly installed on the lower side of the outer peripheral edge of the rotary plate 6, and is configured to collect powder and granular material that has fallen into the bottom cover 20 toward the connection part of the extraction pipe 21. There is.

A lid 28 is provided 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. This rotating cylinder 10 is.

For example, it is connected to a drive device (not shown) by suitable power transmission means such as a pulley 29a and a belt 29b. Note that the upper end of the rotary cylinder 10 and the lower end of the tactile member 12 are rotatably connected by a connecting mechanism, for example, a one-turn joint. 13 is a discharge port connected to the duct 12.

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

Further, directly below the first classifier 30, there is a circulation fan 40 having a rotating shaft 40d that is coaxial with the rotating cylinder 10 which is the rotating shaft of the classifier 30 and rotates separately from the rotating cylinder 10, and has a pair of upper and lower rotating disks. 40a, 40b and blades 14 which are sandwiched between the outer edges of both rotating disks 40a, 40b and have a downward driving force of airflow.
It is equipped with 0c. Further, the upper rotating disk 40a has a circular opening 40e on the inner diameter side, and the lower rotating disk 40a has a circular opening 40e on the inner diameter side.
b has an opening 40f on the outer diameter side.

Both form air flow passages.

Further, on the outer periphery between the classifier 30 and the circulation fan 40, a pair of upper and lower conical guide cones 50a are provided to form a guide path 50 for reversing the direction of the introduced airflow.
50b is the casing 8. It is fixed to the circulation fan 40.

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

Note that the discharge port 13 is connected to a suction blower (not shown) through a powder collecting means such as a bag filter.

The operation of the apparatus of the present invention configured as above will be explained.

In the pulverizing apparatus configured in this manner, the raw material is charged into the pulverizing chamber X from the input pipe 11. On the other hand, with the rotation @ 6, the pole moves in the crushing chamber X due to the combination of the elliptical movement that circulates between the lining 5a of the outer ring 5 and the plate surface 6a, and the orbital movement around the axis of the rotary plate 6. The material is pulverized during a spiral movement similar to that of a rope, and the air introduced from the air introduction pipe 18 into the air introduction chamber 17 and the bottom cover 20 is passed through a 19° clearance slit (or small hole). ) 5b into the grinding chamber X,
It reaches the classifier 30 with the powder generated by the crushing,
After receiving the classification action, the coarse particles are returned to the grinding chamber X again, and the fine particles are transferred to the rotary tube 10 and duct) It is sent to the collection means via the discharge port 13.

It is collected in a collection machine.

Next, to explain the functions of the classifier 30 and the circulation fan 40, the fine particles crushed to a predetermined particle size in the crushing section are conveyed to the airflow of the clearance 19 or the slit 5b mentioned above, rise, and flow along the inner surface of the casing 7. It flows into a guide path 50 formed by guide cones 50a, 50b. The dust-containing airflow that has entered the guide path 50 is divided by the suction force of the rotating classifier 30 and the circulation fan 40, and relatively coarse particles among the fine particles contained in the airflow continue straight and are sent to the circulation fan 40. It is returned to the crushing chamber X via the openings 40e and 40f.

On the other hand, relatively fine particles turn around and easily accompany the airflow toward the blades 30c of the classifier 30, where they are subjected to a classification action, and those that pass through are directed toward the discharge port 13. Due to this classification action, the fine particles thrown off by the blades 30c head towards the circulation fan 40.

Therefore, a group of fine particles with a certain degree of spread in product fineness (fineness) transported by airflow from the crushing chamber
Then, the blades of the classifier rotate to undergo a second classification action (centrifugal classification). On the other hand, the powder produced is usually very small and the classification efficiency is poor. However, in the classifier of the present invention, primary classification is performed as a preliminary classification, so the ratio of powder produced to large particles can be significantly improved. In the case of the example, the downward air flow velocity in the guide path is set to 30 to 50 m/sec, and the air flow rate of the guide path is 60 m''/win, the circulation fan's blowout amount is 50 m''/sin, and the air flow rate introduced to the classifier is 10 m''/win.
If the design is designed to
The air volume per product is reduced, and the classification opportunities are increased by 6 times compared to a model that directly introduces 60tn/win into the classifier.

In addition, since the circulation fan 40 is configured to direct the airflow downward, relatively coarse particles that cannot be used as final products can be immediately returned to the grinding chamber, thereby improving grinding efficiency. In addition, the airflow ejected downward from the circulation fan transports the fine particles to the crushing chamber, then comes into contact with the crushing chamber and reverses itself, guiding the newly crushed fine particles in the crushing chamber toward the classifier, that is, to be more precise. Since the circulating air flow serves as a carrier for conveying the air to the passage 50, energy for air conveyance can be saved. Therefore, clearance 19.
In the above case, the new air introduced into the cabin from the slit 5b is 10m'' for a circulating air volume of 50rn'/ll1n.
/win, so it can be significantly reduced.

In addition, ultrafine powder of 0.1 to 3 μm in size aggregates in units of tens of particles, and although it appears to be coarse particles of several pm to several tens of pm, it is discharged downward from the circulation fan. When the ejected airflow hits the crushing part, it crushes it, which reduces the above-mentioned agglomerated particles and promotes the discharge of ultrafine particles from the device.

Prevent over-grinding.

As described above, the airflow containing the fines particles of the final product that has passed through the classifier 30 heads toward the discharge port 13 as described above.

Note that by making the rotation speed of the classifier and the rotation speed of the circulation fan variable, the product fineness and the circulation air volume can be set or changed as desired. That is, the classification point is controlled by the rotation speed of the classifier, and the circulating air volume within the crusher is controlled by the rotation speed of the circulation fan.

Incidentally, the particles extracted from the grinding chamber through the slit (or small hole) 5b or the clearance 19 are returned to the grinding chamber through the pipe line 21 and the input pipe 11.

This pulverizer has a capacity of 200 to 200 mm depending on the properties of the raw material to be
Rotated at 3000 rpm. Also, the pole is 3-70
A diameter of about mm is suitable.

Since this device comes with a classifier, continuous operation is generally used, but batch operation for testing is also possible.

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

[Effects of the Invention] The centrifugal fluid pulverizer of the present invention has the following features when compared with other types of pulverizers.

That is, in a horizontal crusher such as a ball mill, when the number of revolutions increases, the grinding medium follows the inner surface of the body, so it cannot be rotated as quickly as the critical number of revolutions.

Also, due to the mechanism of Attritor and Tower Mill.

On the other hand, since the stirring rod or rotating blade rotates by pushing the pole apart, the resistance becomes too large and it cannot be rotated at a very fast rotation speed.

In a centrifugal fluid mill, a rotor (rotating plate) and a stator (
The relative speed of the outer ring) can theoretically be increased without limit. Of course, there is no point in increasing the rotation speed beyond a certain level due to technical or economic constraints, but the limit speed is the ball mill or attritor mentioned above.

Much larger than the Tower Mill, therefore.

This is a feature of the device of the present invention because it allows for high-speed pole motion similar to leveling a rope. Very advantageous for grinding action.

Furthermore, in the centrifugal fluid pulverizer, the speed difference between the inner wall surface of the outer ring and the poles is large, and the pulverizing action is excellent.

In addition, 5) the centrifugal fluid pulverizer of the present invention has a guide path formed by a classifier, a circulation fan, and a guide cone, so that (1) it is possible to obtain a product with a sharp particle size distribution with almost no coarse powder flying in;

■Production efficiency is improved because continuous operation is possible.

■ Ultra-fine powder can be classified efficiently.

■Improves grinding efficiency and prevents over-grinding.

■The amount of conveying air introduced into the crusher can be significantly reduced.

It can exhibit excellent effects such as

[Brief explanation of drawings]

FIG. 1 is a sectional view of a centrifugal fluid pulverizer according to an embodiment of the present invention, FIG. 2 is a vertical sectional view of a pulverizing chamber of the centrifugal fluid pulverizer, and FIG.
FIGS. 4(L) and 4(Cb) are schematic sectional views showing the configuration of a conventional crushing device, and FIGS. 4(a) to 4(e) are explanatory diagrams of the rotating plate rotation speed. 5... Outer ring, 6... Rotating plate, 7... Casing, 8... Classifier casing, 10... Rotating tube. , 11... Raw material supply pipe. 12...Duct, 13...Discharge port, 29...Bearing, 30...
・Classifier, 30a, 30b-D rotating disc, 30c...blade, 30d...opening, 40
...Circulation fan, 40a, 40b, one-rotation disk, 40c...blade, 40d...rotating shaft. 40e...opening, 40f...opening, 40
g... Bearing, 50... Guideway, 5
0a, 50b--Guide cone, D...Dish surface (rotating dish). E...Rise part (rotating plate),...Inner wall surface (outer ring),...Crushing chamber.

Claims (1)

[Claims] (1) The rotation axis is installed in the vertical direction, has a conical shape that expands in diameter toward the bottom, and at the same time has a rising portion that expands in diameter toward the top near the outer peripheral edge, and is rotated by a drive device. and a rotating plate having an annular shape whose diameter decreases upward, and which is disposed coaxially with the rotating plate so as to surround the outer periphery of the rotating plate, and is stationary or rotationally driven in the opposite direction to the rotating plate. and a grinding medium housed in a grinding chamber surrounded by the outer ring and a rotating plate, the vertical cross-sectional shapes of the plate surface of the rotating plate and the inner wall surface of the outer ring are each concavely curved. This is a centrifugal fluid grinding device in which the dish surface and the inner wall surface form a continuous smooth surface, and a suction and discharge port is provided at the upper part of the grinding chamber. In a centrifugal fluid pulverizer equipped with a classifier at the bottom, the classifier has a pair of upper and lower rotating disks and a blade sandwiched between the outer edges of the rotating disks, and A central part between the classifiers has an opening that communicates with the discharge port, and a pair of upper and lower rotating disks and a pair of upper and lower rotating disks are sandwiched between the outer edges of the rotating disks on the lower side of the classifier, and a propulsive force for downward airflow is provided at the bottom of the classifier. What is claimed is: 1. A centrifugal fluid pulverizer comprising: a circulation fan equipped with blades having the following characteristics; and a guide passage in which the direction of air flow is reversed at an outer periphery between the classifier and the circulation fan.