JPH0331097B2 - - Google Patents

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 milling device that is equipped with a fixed ring and a rotating plate, and that grinds raw materials by centrifugally flowing a grinding 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 the crushing devices have a rotary plate facing upward,
By rotating this rotary plate, grinding media such as steel balls (hereinafter referred to as balls) housed inside
A vertical ball mill, commonly called a vertical ball mill, is known in which the raw material is pulverized and milled by circulating the ball.

FIG. 2a is a schematic sectional view showing an example of the configuration of a conventional vertical ball mill. Reference numeral 1 denotes a rotary plate, the rotational axis of which is disposed in the vertical direction, and is rotatable about this axis by a drive shaft 2 . The rotary plate 1 includes a substantially planar bottom surface B and an inclined side surface A whose diameter increases upward. Reference numeral 3 is a fixed cover, which has a ring shape;
Its inner surface has a semicircular cross-section. In the conventional device shown in FIG. 2a, as the rotary plate 1 rotates, the ball climbs up the side surface A from the bottom surface B, then moves toward the center along the lower surface of the fixed cover 3, and then moves to the center side of the fixed cover 3. Separate from the bottom surface B
fall on top.

FIG. 2b is a schematic sectional view showing another example of the structure of a conventional vertical ball mill. In the conventional example shown in FIG. 2b, the rotary plate 4 has a conical portion 5 at its center, and the ball that has separated from the lower surface of the fixed cover 3 hits the side surface C of the conical portion 5. Then, it falls onto the bottom surface B of the rotating plate 4.

[Problems to be solved by the invention] In a vertical ball mill as shown in Fig. 2,
The pulverizing action is mainly carried out by sliding of the side surface A of the rotary plates 1, 4 and the ball, which is a so-called pulverizing method. This sliding includes vertical sliding of the ball climbing up the side surface A, and a speed difference between the circumferential speed of the rotating plate side surface A and the circumferential speed of the ball around the rotating plate 1 or 4 axes. There are two types of sliding caused by

However, in the conventional vertical ball mill,
Since the side surface A of the rotating plates 1 and 4 also forms a part of the rotating plate 4, the side surface A rotates in the same circumferential direction as the ball. Therefore, the rotational speed in the circumferential direction between the side surface A and the ball is not so large.
The crushing and grinding action due to this circumferential velocity difference becomes weak.

In addition, centrifugal force is applied to the ball by the rotation of the rotary plates 1 and 4, and the ball crawls up the side surface A due to this centrifugal force and gains potential energy. However, in the conventional example shown in FIG. 2, almost all of the potential energy obtained by the ball is consumed when the ball detaches from the lower surface of the fixed cover 3, falls, and hits the bottom surface B, resulting in crushing and grinding. It cannot be used for action. In the conventional device shown in FIG. 2b, 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, so how much of the potential energy the ball obtains is This is converted into velocity energy and can be used for crushing and grinding. However, if the ball is on the side C
The energy loss caused by the collision is quite large.

As described above, in the conventional grinding device commonly called a vertical ball mill, the grinding and grinding action is weak, or the energy input into the device is easily consumed for purposes other than the grinding and grinding action, resulting in low energy efficiency. There were problems such as.

[Means for Solving the Problems] The centrifugal fluid crushing device of the present invention includes a rotating plate and a fixed ring coaxially fixed to the rotating plate so as to surround the outer periphery of the rotating plate. It is configured to accommodate a ball. The rotary plate is installed so that its axis of rotation is vertical, and has a conical shape whose diameter increases downward. The plate surface of the rotating plate and the inner wall surface of the fixed ring each have a vertical cross-sectional shape concavely curved in an arc shape, and
This dish surface and the inner wall surface of the fixed ring form a continuous smooth surface. Further, a plurality of grooves having a width larger than the grinding medium are provided on one or both of the dish surface and the inner wall surface of the fixed ring.

[Function] In the centrifugal fluid crushing device of the present invention, since the side surface is a fixed surface, the difference in speed in the circumferential direction between the balls and the side surface becomes large, and the crushing and grinding action in this side surface portion becomes significantly large.

In addition, since the balls roll along the plate surface of the rotating plate, the potential energy obtained when the balls crawl up the side wall can be efficiently converted into velocity energy, reducing the loss of energy input into the device. Very few.

Furthermore, the grooves provided on the dish surface and the inner wall surface of the fixed ring impart irregularities to the ball movement, further improving the crushing efficiency.

According to the invention, slag, portland cement clinker, limestone, coal, mica,
Various materials such as ceramics such as alumina can be crushed extremely efficiently.

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

1A to 1E are a cross-sectional view and a plan view of a centrifugal fluid pulverizer according to an embodiment of the present invention. In each figure, reference numeral 6 denotes a rotary plate, the rotating shaft of which is installed in the vertical direction, and a liner 6a affixed to the plate surface. The rotary plate 6 has a conical shape whose diameter increases downward. This rotary plate 6 is connected to the drive shaft 2
Rotationally driven by.

Reference numeral 7 denotes a fixed ring, which is fixed coaxially with the rotating plate 6 so as to surround the outer periphery of the rotating plate 6. The fixed ring 7 has a shape that decreases in diameter toward the top,
The lower part of the fixed ring 7 and the outer peripheral edge of the rotary plate 6 are in slidable contact with each other. Furthermore, as shown in Fig. 4,
A small gap of, for example, about 10 to 30% of the minimum ball diameter may be provided between the lower part of the fixed ring 7 and the outer peripheral edge of the rotary plate 6.

The plate surface D of the rotating plate 6 and the inner wall surface E of the fixed ring 7 are
Both have concavely curved vertical cross-sectional shapes, and the contact portion between the dish surface D and the inner wall surface E forms a smoothly continuous surface.

A plurality of grooves F are protrudingly provided on one or both of the plate surface D of the rotary plate 6 and the inner wall surface E of the fixed ring 7.

In FIG. 1a, a plurality of grooves F are provided on the dish surface D. This groove F extends in the radial direction as shown in FIG. 1b. In FIG. 1c, the groove F in the dish surface D is arcuate and curved to the downstream side in the direction of rotation of the dish surface. Figure 1d
In this case, arc-shaped grooves F are oriented in the circumferential direction of the dish surface D. In Figures 1a to d, the depth of the groove is preferably about 5 to 30% of the ball diameter.
The width of the groove is preferably about 100 to 500% of the ball diameter.

In FIG. 1e, the grooves extending in the radial direction are wide, and the dish surface D is provided with wave-like undulations in the circumferential direction. Figure 1 f is a cross-sectional view taken along the line f-f in Figure 1 e, showing the shape of the waveform undulations. In some cases, it is preferable that a=0.005d to about 0.05d. Also, the pitch of the waves b
is preferably about 3 to 5 times as large as a.

In FIGS. 1a to 1f, grooves are provided on the dish surface D, but such grooves may also be provided on the inner wall surface E of the fixed ring, or only on the inner wall surface E. FIG. 1g is a front view of the inner wall surface when the inner wall surface E is provided with a groove F extending in a direction inclined at a predetermined angle with respect to the vertical direction.

Next, the operation of the above embodiment device will be explained.

For clarity of explanation, first, the movement of the ball in a state where the groove F is not installed will be explained with reference to FIG. 1h.

In FIG. 1h, balls are housed in a grinding chamber surrounded by a rotary plate 6 and a fixed ring 7, and the raw material to be crushed is introduced into the grinding chamber, and the rotating plate 6 is
Rotate. Then, the ball is moved in the outer circumferential direction by centrifugal force, and by this velocity energy, it crawls up the inner wall surface E of the fixed ring 7, and then leaves the inner wall surface E and lands on the plate surface D of the rotary plate 6 in an almost tangential direction. Land smoothly on the bed. The ball that has moved onto the plate surface D rolls down along this plate surface D, and is again moved toward the fixed ring 7 by the centrifugal force exerted by the rotation of the rotary plate 6.

Further, when the rotary plate 6 is rotated, the balls revolve in the circumferential direction at a speed slower than the rotational speed of the rotary plate 6. Therefore, in addition to the vertical circular movement that circulates between the plate surface D and the inner wall surface E as described above, the ball also performs a revolving movement that rotates around the axis of the rotary plate 6, and performs these two movements. It performs a spiral motion that resembles winding the composite rope. (This movement of the ball is referred to as centrifugal pulsating flow in this specification.) In this way, the ball moves up the inner wall surface E while maintaining its movement in the circumferential direction of the rotary plate 6. However, since this inner wall surface E is fixed, the composite speed of the circumferential direction speed (revolution speed) of the ball and the creeping speed of the ball becomes the speed difference between the inner wall surface E and the ball. Therefore, the speed difference between the balls and the inner wall surface E becomes extremely large, and the crushing and grinding action of the balls when moving on the inner wall surface E becomes extremely strong.

Furthermore, since the ball that leaves the inner wall surface E and lands on the dish surface D smoothly rolls down along this dish surface D, there is extremely little energy loss when the ball collides with the dish surface D. , the potential energy obtained when running up the inner wall surface E can be converted into kinetic energy in the radial direction by the motion of rolling down the plate surface D, so the energy once applied to the ball can be used as a mischief. It can be effectively used for crushing and grinding without being consumed. Furthermore, when descending along the dish surface D, the balls slide on this dish surface D, so that the raw material is pulverized even during this downward movement.

Therefore, in the present invention, for example, FIG.
As shown in g, the dish surface D or the fixed ring inner wall surface E
are provided with grooves F, and these grooves F add irregularity to the overall circulation movement of the balls, increasing the frequency of contact between the balls and the object to be crushed, and significantly improving the crushing action. .

In addition, in the centrifugal fluid pulverizer of the present invention,
The rotational speed of the rotary plate may be constant, but it may also be varied regularly or irregularly. By varying the rotational speed, strong irregularities are imparted to the movement of the balls and the grinding action is improved.

FIGS. 3a to 3e are schematic diagrams illustrating the temporal pattern of the rotational speed N of the rotary plate. In Figure 3a, the rotating plate is rotated at a constant speed. At point 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, and this process is repeated. .
At d, the rotational speed varies according to a sawtooth waveform. In addition, at e, the sawtooth waveform is changed to gradually reach the maximum rotational speed, and thereafter the same waveform is repeated with rapid deceleration.

Further, according to the research of the present inventor, when the vertical cross-sectional shape of the dish surface D and the inner wall surface E is made to have an arc shape as shown in FIG. 4, an even more excellent crushing action can be achieved. was recognized. R ₁ and R ₃ are
It shows the radius of each arc. Also,
If the inner diameter of the lower end of the fixed ring 7 is R ₂ , the lower corner of the fixed ring 7 also has an arc-shaped cross section, and the radius ΔR of the arc is ΔR = R ₁ − R ₂ , then the continuity of the surface It was also found that the texture was smooth and suitable.

In the above embodiment, the lower outer circumferential surface of the rotary plate 6 and the lower inner circumferential surface of the fixed ring 7 face each other at the lowest level of the concave curved surface formed by the plate surface D and the fixed ring inner wall surface E. are doing. However, in the present invention, as shown in FIG. 5, the opposing portion may be located at a position different from the lowest level. In Fig. 5a, the opposing part T
is arranged on the outer peripheral side than the lowest level part S, and in the same b, the opposing part T is arranged on the inner peripheral side than the lowest level part S.

The apparatus of the invention can be of both continuous and batch milling types. In the case of a batch-type crusher, a lid 7a that can be opened and closed may be attached to the upper opening of the fixed ring 7, as shown in FIG. A continuous crushing device is illustrated in FIG. 6 below.

FIG. 6 is a sectional view showing an example of the overall configuration of the device of the present invention when it is actually operated.

Reference numeral 8 denotes a casing that covers the main body of the crusher, and the fixed ring 7 is attached to the inner surface of the casing 8 via a connecting member 9. Reference numeral 10 is a pillar, which is connected to the rotary plate 6 via a bearing 11.
is centrally supported. The rotating shaft 2 is connected to a driving device such as an electric motor via a speed reduction mechanism or the like.

A raw material input pipe 12 is installed in the center of the ceiling of the casing 8, and an opening 13 is provided surrounding the input pipe 12.
A duct 14 is connected to.

In this embodiment, the fixed ring 7 is lined with a liner and has a large number of slits or small holes 15 bored through its wall surface. Further, in this embodiment, a groove F is provided in the dish surface D. The structure of this groove F is similar to that shown in FIG. 1a.

A side cover 16 is provided between the bottom of the outer surface of the fixed ring 7 and the inner surface of the casing 8, and an air introduction chamber 17 is defined between the side cover 16, the casing 8, and the outer surface of the fixed ring 7. and air introduction pipe 1
Air can be introduced from 8. Note that the upper end of the side cover 16 is sealed to the outer side surface of the fixed ring 7.

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 bottom inner peripheral edge of the fixed ring 7, and the bottom cover 20 covers the lower side of this clearance 19. It is surrounded by In this embodiment, air can also be introduced into the bottom cover 20 by providing a through hole in the side cover 16 or connecting an air introduction pipe.

The bottom cover 20 and the air introduction chamber 17 include:
A pipe line 21 for extracting and transporting powder and granular material is connected,
This pipe line 21 is arranged to be able to return the powder to the input pipe 12. Further, a scraper 22 is fixedly installed on the lower side of the outer peripheral edge of the rotary plate 6, and a bottom cover 20
It is configured to collect the powder particles that have fallen into the pipe toward the connection part of the extraction pipe 21.

Note that the duct 14 is connected to powder collection means (not shown) such as a bag filter. (A classification means may be installed upstream of the collection means.) In the crushing apparatus configured in this way, the raw material is introduced into the apparatus from the input pipe 12. rotating plate 6
As the ball 23 rotates, the ball 23 performs a spiral motion similar to that of a rope due to the combination of the circular motion that circulates between the inner wall surface of the fixed ring 7 and the disk surface, and the revolving motion around the axis of the rotating disk 6. Pulverize the raw materials. Further, irregularities are imparted to this ball movement by the ball coming into contact with the groove F. The air introduced into the air introduction chamber 17 and the bottom cover 20 from the air introduction pipe 18 flows into the grinding chamber through the clearance 19, the slit or the small hole 15, and flows into the duct 14 with the powder produced by the grinding. Go inside,
It is sent to classification means or collection means. The fine particles entrained in the air are collected by the collection means.

Note that a classification means is installed on the downstream side of the duct 14, and when it is possible to separate particles with a relatively large particle size by this classification means, the separated coarse particles are passed through the input pipe 12 again. Insert into the device.

Further, the particles that have escaped from the grinding chamber through the slit or small hole 15 or the clearance 19 are returned into the grinding chamber through the conduit 21.

This device is rotated, for example, at 200-3000 rpm. Further, it is preferable that the ball has a diameter of about 3 to 70 mm.

Although the above description relates to a type of centrifugal fluid pulverizer in which the fixed ring is stationary, the centrifugal fluid pulverizer of the present invention may be configured to rotate the fixed ring 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, and therefore cannot be rotated faster than the critical number of revolutions. Furthermore, due to the mechanism of attrition mills and tower mills, the stirring rod or rotating blade rotates in such a way as to push the balls apart, so the resistance becomes too large and they cannot be rotated at very high rotational speeds. On the other hand, in a centrifugal fluid mill, the relative speed of the rotor (rotating plate) and stator (fixed ring) can be increased theoretically without limit. Of course, it is meaningless to increase the rotation beyond a certain level due to technical or economic constraints, but the critical speed is much greater than that of the ball mill, attrition mill, or tower mill. Therefore, a ball movement similar to that of a rope can be adopted at high speed, which is extremely effective against the grinding action that is a feature of the apparatus of the present invention.

As described above, in the centrifugal fluid pulverizer of the present invention, the speed difference between the inner wall surface of the fixed ring and the balls is large, and the pulverizing action is excellent. Further, since the potential energy of the ball that has separated from the inner wall surface of the fixed ring and landed on the dish surface can be converted into only kinetic energy in the radial direction, the loss of energy input into the device is extremely small. Furthermore, the crushing action is also performed by the balls sliding along the dish surface.

In addition, the grooves provided on the dish surface and the inner wall surface of the fixed ring impart irregularities to the movement of the balls, so that the crushing efficiency is further improved.

Therefore, according to the centrifugal fluid pulverizer of the present invention,
It is also possible to significantly increase the pulverization efficiency and to significantly reduce the power source unit (for example, electric power consumption) required for pulverization.

[Brief explanation of drawings]

Figures 1a to 1g are explanatory diagrams of the configuration of a centrifugal fluid pulverizer according to an embodiment of the present invention, Figure 1h is an explanatory diagram of the operation of the apparatus of the present invention, and Figures 2a and b are configurations of conventional pulverizers, respectively. Schematic cross-sectional views showing FIGS. 3a-e
is an explanatory diagram of the rotating plate rotation speed, and FIGS. 4, 5, and 6 are longitudinal cross-sectional views of different embodiments of the apparatus. 1, 4, 6... Rotating plate, 7... Fixed ring, D...
Disc surface, E...Inner wall surface of fixed ring, F...Groove.

Claims (1)

[Scope of Claims] 1. A rotary plate having a conical shape whose rotational axis is disposed vertically, whose diameter expands downward, and which is rotated by a drive device; A crushing device comprising: a fixed ring having an annular shape and fixed coaxially with the rotating plate so as to surround the outer periphery of the rotating plate,
A grinding medium is housed inside the device, and the vertical cross-sectional shapes of the plate surface of the rotary plate and the inner wall surface of the fixed ring are each concavely curved in an arc shape, and the plate surface and the inner wall surface are different from each other. A centrifuge characterized in that a continuous smooth surface is formed, and a plurality of grooves having a width larger than the grinding medium are provided on at least one of the plate surface of the rotary plate and the inner wall surface of the fixed ring. Fluidized crushing equipment.