JPH04200657A - Centrifugal fluidization grinder - Google Patents

Abstract

PURPOSE:To rapidly separate fine powder from a ball and coarse particles and to discharge it to the outside of the system by intermittently constituting a ball group of a grinding medium and a raw material to be ground and intermittently breaking the spiral proceeding movement of the ball group by presence of a guide groove and an injection hole. CONSTITUTION:A guide groove 50 for a grinding medium such as a steel ball or a ceramic ball is provided at a plurality of pieces in the equal intervals in the vertical direction or the oblique direction of the inner wall face 1A of a fixed ring 1. The cross section of this guide groove 50 is constituted of a bottom face 50a and the side walls 50b of both sides. This cross section has a nearly channel-shaped form. The guide groove 50 is constituted so that in a starting point thereof, the bottom face 50a and the side faces are begun to bury outside in the outside direction and further gradually apart in the direction to an introduction hole 60 from the inner wall face 1A of the fixed ring 1. The bottom face 50a gradually approaches the inner wall face 1A as it proceeds to the oblique upper part. In an end point of the guide groove 50, the bottom face 50a is allowed to coincide with the inner wall face 1A. Further, the introduction hole 60 of gas is provided to a wall face 50c formed in the starting point of the guide groove 50 and penetrated through the fixed ring 1 and also upward directed along the inner wall face 1A of the fixed ring 1.

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 ball) is circulated to grind and grind raw materials.

FIG. 5(a) is a schematic cross-sectional view showing an example of the configuration of a conventional vertical ball mill. Reference numeral 100 is a rotating plate;
This rotational axis is installed in the vertical direction, and is rotatable around this axis by a drive shaft 200. rotating plate 10
0 has a substantially flat bottom surface B and an inclined side surface A whose diameter increases upward. Reference numeral 300 denotes a fixed cover, which is ring-shaped and whose inner surface has a semicircular cross-section. In the conventional device shown in FIG. 5(a), as the rotary plate 100 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 300, and then is fixed. It separates from the cover 300 and falls onto the bottom surface B.

FIG. 5(b) is a schematic cross-sectional view showing another example of the configuration of a conventional vertical ball mill. In the conventional example shown in FIG. 5(b), the rotary plate 400 has a conical portion 50 at its center.
0, and the ball detached from the lower surface of the fixed cover 300 hits the side surface C of this conical portion 500 and then falls onto the bottom surface B of the rotary plate 400.

However, in a vertical ball mill as shown in FIG.
This is a so-called grinding method in which a ball slides against a side surface A of 0.400 mm. This sliding includes a vertical sliding movement in which the ball climbs 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 100 or 400 axis. There are two types of sliding caused by

However, in the conventional vertical ball mill, the rotary plate 1
00.400 is also part of the rotating plate 400, so the side 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, and the crushing and grinding effects caused by this circumferential speed difference are weak.

In addition, centrifugal force is applied to the ball by the rotation of the rotary plates 100, 400, 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. 5, almost all of the potential energy obtained by the ball is consumed when the ball detaches from the lower surface of the fixed cover 300, falls, and hits the bottom surface B.
It cannot be used for grinding and grinding operations. Fifth
In the conventional device shown in Figure (b), the ball falling from the lower surface of the fixed cover 300 is bounced off the side surface C of the conical part 500 and a radial force is applied to the ball, so the potential energy obtained by the ball is Some of it can be converted into velocity energy and used for crushing and grinding operations. However, since the ball bounces off side C,
The energy loss due to 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.

Therefore, the present applicant filed a patent application for a centrifugal fluid pulverizer having a rotating plate and a fixed ring as described below. (Special application 1986
-265379, 60-266867 to 26687
No. 2, No. 61-99745, etc.).

This rotary plate has a rotation axis oriented in the vertical direction, has a plate surface whose diameter expands downward at least in the center, and is rotatable in a shape in which the longitudinal section of the plate surface is curved in a concave shape. It is plate-shaped.

The fixed ring has an inner wall surface whose diameter decreases upward at least in the upper part, and a vertical cross section of the inner wall surface is curved in a concave shape, and is disposed coaxially around the rotary plate and is stationary. ing.

In the centrifugal flow device, the plate surface of the rotating plate and the inner wall surface of the fixed ring are formed into continuous smooth surfaces except for a small gap between the rotating plate and the fixed ring.

[Problems to be Solved by the Invention] In such a centrifugal flow device, the balls as the grinding medium and the pulverized raw material are placed inside the grinding chamber surrounded by the plate surface of the rotating plate and the inner wall surface of the fixed ring. While revolving in the circumferential direction at a speed slower than the rotational speed, it also performs a circular motion in the vertical direction that circulates between the dish surface and the inner wall surface, and these two movements are combined to create a spiral movement similar to that of a rope ( This motion is commonly known as centrifugal flow.) In the process of three-dimensional motion called centrifugal flow, the grinding action of the raw material and the balls, which are held between individually rotating balls, and the aggregate of the raw material and balls (ball group). Due to the crushing action caused by sliding on the wall surface of the three-dimensional movement, efficient crushing is carried out and the crushing progresses rapidly. On the other hand, over-pulverization tends to occur, and a large amount of fine powder is included in the aforementioned ball group, and it is difficult for the fine powder to separate from this ball group. This tends to cause problems such as agglomeration and granulation. This, in turn, encouraged over-grinding, creating a vicious cycle.

[Means for Solving the Problems] In order to solve the above problems, the centrifugal fluid milling device of the present invention includes a dish whose rotational axis is vertically oriented and whose diameter expands downward at least in the central portion. a rotatable circular rotary plate having a shape in which the longitudinal section of the plate surface is curved in a concave shape; has a concavely curved longitudinal section, and includes a stationary stationary ring coaxially disposed around the rotating plate, and a plate surface of the rotating plate and an inner wall surface of the stationary ring are in contact with each other. , in a centrifugal fluid milling device in which a continuous smooth surface is formed except for a minute gap between a rotating plate and a fixed ring, steel balls are provided along the vertical or inclined direction of the inner wall surface of the fixed ring; Alternatively, a plurality of guide grooves for grinding media such as ceramic balls are provided at equal intervals around the circumference, and the guide groove has a substantially U-shaped cross section consisting of a bottom surface and side walls on both sides thereof. At the starting point, the bottom surface and side surfaces are buried outward from the inner wall surface of the fixed ring, and as they go diagonally upward, the bottom surface gradually approaches the inner wall surface, and at the end point of the guide groove, the bottom surface matches the inner wall surface. a wall surface formed at the starting point of the guide surface, penetrating the fixed ring, and
The structure is such that an upward gas injection hole is provided along the inner wall surface of the fixed ring.

[Function] In the centrifugal fluid pulverizer of the present invention, a plurality of guide grooves each having a generally U-shaped cross section are provided diagonally along the inner wall surface of the fixed ring at equal intervals around the circumference. At the starting point of the side, the guide groove is buried outside the inner wall surface, so during operation, the balls and powder flowing centrifugally in the grinding chamber formed by the rotating plate and the inner wall surface of the fixed ring. When a group of balls consisting of The fluid flows into the grinding chamber through the gap between the grinding device and the fluid flowing out due to the suction force of a suction fan installed downstream of the grinding device. This tendency is more pronounced as the fineness of the powder decreases, so the fine powder easily separates from the ball group and is discharged out of the system. On the other hand, the balls and coarse particles that have entered the guide groove fall into the guide groove, move along the guide groove, and fall again from the upper end of the guide groove, which is the end point of the guide groove, toward the rotating plate, where they are crushed. continue.

[Example 1] Hereinafter, an example of the present invention will be described based on the drawings.

Figures 1 to 4 relate to embodiments of the present invention, with Figure 1 being an overall side view, Figure 2 being a vertical sectional view of main parts, and Figure 3 being Figure 2 III.
-III schematic plan view, FIG. 4(a) is an enlarged vertical cross-sectional view of the main part, and FIG. 4(b) is a perspective view of the main part.

In the figure, numeral 1 is a fixed ring, and 2 is a rotating plate. The fixed ring 1 is fixed on the upper side of a drum-shaped casing 4 whose bottom surface is sealed with a plate 3, and the plate 3 is supported by a pedestal 5. A support block 6 is fixed to the rotating plate 2, and the support block 6 is supported by the plate 3 via a bearing device 7. That is, an opening 8 is formed in the center of the plate 3, and a bearing housing 9 is formed in the center of the plate 3.
A flange portion 10 is engaged with the edge of the opening 8 and fixed with bolts 11. A drive shaft 12 is connected to the lower side of the support block 6, and the drive shaft 12 is connected to a joint 13.
It is connected to the output shaft 15 of the reduction gear 14 via. Reference numeral 17 is a variable speed motor for driving, and the deceleration I! 1
It is connected to 4.

A lid member 18 is attached to the upper side of the rotating plate 2.

The lid member 18 is provided with a flange 19 on the outer periphery of the lower end, and the flange 19 is placed on a flange 20 protruding from the outer periphery of the upper end of the fixed ring 1, and is fixed with bolts 21. A discharge pipe 22 is installed in the center of the lid member 18, and inside the discharge pipe 22 there is a fixed ring 11, a rotating plate 2, and a lid member 1.
It communicates with a chamber 23 for crushing or reforming (hereinafter referred to as a crushing chamber) surrounded by 8. The lid member 18 is provided with an input pipe 24, and the inside of the input pipe 24 is a crushing chamber 23.
It communicates within.

Next, the configurations of the fixed ring 1 and the rotary plate 2 will be explained in detail with reference to FIG.

The fixed ring 1 is of an annular shape installed with the axial direction in the vertical direction, and the diameter is the largest at a midway portion in the height direction (hereinafter referred to as the middle portion) lb. The fixed ring 1 has the middle part 1b
A lower part (hereinafter referred to as the lower part) lc is slightly reduced in diameter from the middle part to the upper part (hereinafter referred to as the upper part) 1a. Therefore, the inner wall surface IA of the fixed ring 1 extends from the lower IC to the middle lb.
The diameter slightly expands towards the center, and the middle part 1b is approximately vertical.
It has a shape that decreases in diameter from the middle part 1b toward the upper part 1a,
Moreover, the longitudinal section of the inner wall surface IA is curved in a concave shape. A flange 25 is provided protruding from the outer peripheral surface of the middle portion 1 b of the fixed ring 1 , and the flange 25 is placed on a flange 26 protruding from the outer periphery of the upper end of the casing 3 and fixed with bolts 27 .

The plate surface 2A of the rotary plate 2 has a shape whose diameter increases downward at the central portion 2a, and is continuous to the central portion (approximately horizontal at the intermediate portion 2b, and has an outer circumferential portion that continues from the intermediate portion 2b). 2C has a shape whose diameter expands upward.The plate surface 2A is curved concavely as a whole, and the inner wall surface IA of the fixed ring 1 and the plate surface 2A are connected to the fixed ring 1 and the rotary plate 2.
A continuous smooth surface is formed except for a small gap 29 between the two.

A pointed cap 30 is attached to the center of the rotary plate 2 and fixed with a bolt 31. A shaft hole 32 is bored in the center of the rotary plate 2, and the upper end of the support block 6 is fitted into the shaft hole 32. The lower end of the bolt 31 is connected to a piece 33 provided at the upper end of the support block 6.
are screwed together.

Although not shown, liners are attached to the inner wall surface IA of the fixed ring 1 and the plate surface 2A of the rotary plate 2, respectively.

Further, in the inner wall surface IA of the fixed ring 1, a guide groove 50 is provided which is inclined from the vertical direction by an inclination angle θ in the direction of rotation from the bottom to the top.
A plurality of (four in the embodiment shown in FIGS. 1 to 3) are arranged equally spaced around the circumference. The guide groove 50 has a bottom surface 50a and a bottom surface 50.
It is made up of side walls 50b, 50b on both sides perpendicular to a, and has a substantially U-shape. As shown in FIGS. 1 and 2, the depth H of the bottom surface 50a is approximately three times the diameter of the built-in ball, and the inner width W of the bottom surface 50a is approximately twice the depth H. The depth of the bottom surface 50a gradually decreases upward from the bottom end, and at the top end, the depth becomes O, which is configured to match the inner wall surface IA of the fixed ring 1. Therefore, the side walls 50b on both sides sequentially apply N pressure to the inside of the inner wall surface IA as they move upward.

In addition, as shown in the embodiment of FIG.
It is desirable to select within the range of 30° to 30°. Further, a wall surface 50c formed at the starting point of the guide groove 50 has an inner wall surface IA1. An upward air injection hole 60 called l:iG is provided.

The plate 3 is provided with an inlet 34 for introducing gas such as air, and the gas is introduced into the gas chamber 3 in the casing 4 through a pipe 35.
6 can be introduced. Therefore, gas also flows into the grinding chamber from the injection hole 60.

Further, a powder collecting means (the illustrated path) such as a bag filter is connected to the discharge pipe 22.

Next, a description will be given of the process of pulverizing a pulverized raw material made of a refractory material using the centrifugal fluid pulverizer configured as described above.

A large number of grinding media made of, for example, spherical balls are charged into the grinding chamber 23 in advance. First, the pulverized raw material is introduced into the apparatus through the input pipe 24. As the rotary plate 2 rotates, the grinding raw material and the grinding medium undergo a circular motion (arrow S) that circulates between the inner wall surface IA of the stationary 81 and the plate surface 2A, and a circular motion of the rotary plate 2 around its center. A spiral movement (centrifugal flow) is performed to create a pulverized material, and the pulverized raw material is ground or stripped during this period.

That is, when the rotary plate 2 is rotated, the grinding medium is moved in the outer circumferential direction by centrifugal force, and this velocity energy causes it to crawl up the inner wall surface IA of the fixed ring 1, and when the climbing force becomes smaller than gravity, it It leaves the inner wall surface IA and falls onto the plate surface 2A of the rotating plate 2. The grinding medium that has moved onto the dish surface 2A is moved toward the fixed ring 1 again along this dish surface 2A.

Further, when the rotary plate 2 is rotated, the grinding medium revolves in the circumferential direction at a speed slower than the rotational speed of the rotary plate 2. Therefore, as described above, the grinding medium is divided into the dish surface 2A and the inner wall surface IA.
In addition to the circular movement S in the vertical direction that circulates, the rotating plate 2 also performs an orbital movement that rotates around the axis, and these two movements are combined to create a spiral movement (centrifugal flow) that resembles a rope.
Do this.

In this way, the grinding medium moves up the inner wall surface IA while maintaining its movement in the circumferential direction of the rotary plate 2. When the inner wall surface IA is fixed, the grinding medium moves up the circumferential direction of the rotating plate 2. The composite speed of the directional speed (revolution speed) and the creeping speed of the grinding medium directly becomes the speed difference between the inner wall surface IA and the grinding medium. Therefore, the speed difference between the grinding medium and the inner wall surface IA becomes extremely large, and the grinding action of the grinding medium when moving on the inner wall surface IA becomes extremely strong.

Furthermore, since the grinding media that has separated from the inner wall surface IA and landed on the dish surface 2A smoothly rolls down along this dish surface 2A, the movement when moving down the dish surface 2A lowers the inner wall surface IA. Since the drive unit can convert the potential energy obtained during upward movement into kinetic energy in the radial direction, the energy once applied to the grinding medium can be effectively used for the peeling action without wasting it. . Furthermore, when descending along the dish surface 2A, the grinding media
Since it slides on the surface, grinding or peeling occurs even during this downward movement.

The grinding action in the grinding chamber described above (in addition to compression, grinding,
(including exfoliation, etc.) is preferably carried out on hard and brittle materials with a specific gravity much greater than 1, such as silica, alumina, and ceramics, but on the other hand, the disadvantage is that the crushing efficiency is too high. , over-grinding is likely to occur. This is because it is difficult for the fine powder that has been pulverized to the required particle size to separate from the group of balls that are performing the aforementioned spiral movement (centrifugal flow). When such a group of balls reaches the starting point of the guide groove 50 during movement in the grinding chamber, as shown by the black circle in FIG. The liquid then falls into the air, rises along the bottom surface 50a, and is ejected into the air again from near the uppermost end of the guide groove 50, heading toward the rotating plate 2. on the other hand,
The fine powder is discharged from the grinding device by the air flow flowing from the bottom to the top of the grinding chamber through the injection hole 60 and the gap 29, so that it is separated from the balls and coarse particles. White circle in Figure 2
is a group of balls not along the guide groove 50a but along the inner wall surface IA.

゛As described above, as the normal spiral movement continues, the fine powder is efficiently taken out of the system.
Over-grinding is prevented.

The pulverization proceeds as described above, and the discharge of the material after the pulverization is as follows. That is, piping 3
5. When an appropriate amount of air is introduced into the grinding chamber 23 through the gas chamber 36, the injection hole 60, and the gap 29, and the centrifugal flow grinding as described above is continued for a certain period of time, the grinding raw material is peeled off by grinding or stripping. The fine powder is discharged from the discharge pipe 22 together with air. Note that a classifier may be provided at the top of the centrifugal fluid pulverizer of the present invention to discharge only the required fine powder.

Note that since gas is blown from the gap 29 into the pulverized raw material and the pulverizing medium that are being subjected to centrifugal flow pulverization, the fine powder of the pulverized raw material is immediately conveyed by airflow and discharged. For this reason, −
The fine powder that has been peeled off will not adhere to the base material again.

Of course, air can also be introduced into the grinding chamber 23 by suctioning from the discharge pipe 22 instead of by blowing air from the pipe 35.

In this way, it is possible to reliably pulverize pulverized raw materials that are extremely light or difficult to crush, and to efficiently obtain pulverized raw materials with high purity.

[Effects of the Invention] As explained above, in the centrifugal flow milling apparatus of the present invention, the presence of the guide groove and the injection hole allows the spiral movement of the ball group consisting of the milling medium and the milling raw material to be intermittently controlled. By intermittent destruction, fine powder can be quickly separated from balls and coarse particles and carried out of the system. Therefore, over-pulverization can be prevented and agglomeration of fine powder can be eliminated, thereby improving the crushing efficiency.

[Brief explanation of the drawing]

Fig. 1 to Fig. 4 relate to an embodiment of the present invention, Fig. 1 is an overall side view, Fig. 2 is a vertical sectional view of main parts, and Fig. 3 is Fig. 2 m-■.
Fig. 4(a) is an enlarged vertical sectional view of the main part, Fig. 4(b) is a perspective view of the main part, and Fig. 5 (al and (bl) respectively show the configuration of a conventional crushing device. It is a schematic cross-sectional view. 1... Fixed ring, 2... Rotating plate, IA... Inner wall surface, 2A... Disc surface, 3...
...Plate, 4...Casing, 14...Reducer, 17...
Motor, 18... Lid member, 22...
...Discharge pipe, 23...Crushing chamber, 24
...Input pipe, 29...Gap,
50 river...guide groove, 50a...bottom,
50b...Side wall, 50c...Wall surface, θ・
・・・・・・・・Inclination angle of guide groove, W・・・・・・・・・
Inner width of guide groove, H----, Depth of guide groove, 60.
...Injection hole. Patent applicant: Ube Industries, Ltd. Figure 1 1), O0 Figure 5 (a) (b)

Claims (1)

[Claims] (1) A rotatable motor whose rotational axis is vertically oriented, has a flattened surface whose diameter expands downward at least in the central portion, and whose vertical cross section is concavely curved. It has a circular rotating plate and an inner wall surface whose diameter decreases upward at least at the upper part, and the longitudinal section of the inner wall surface is curved in a concave shape,
A stationary ring is provided coaxially around the rotating plate and is stationary, and the plate surface of the rotating plate and the inner wall surface of the fixed ring are in contact with each other, except for a minute gap between the rotating plate and the fixed ring. In the centrifugal fluid crushing device, which is formed on a continuous smooth surface, a guide groove for a crushing medium such as a steel ball or a ceramic ball, which is provided along the vertical direction or an inclined direction of the inner wall surface of the fixed ring, is circumferentially formed. A plurality of guide grooves are provided at equal intervals, and the guide groove has a substantially U-shaped cross section consisting of a bottom surface and side walls on both sides thereof,
At the starting point of the guide groove, the bottom surface and side surfaces are buried outward from the inner wall surface of the fixed ring, and as they go obliquely upward, the bottom surface gradually approaches the inner wall surface, and at the end point of the guide groove, the bottom surface is buried outward from the inner wall surface of the fixed ring. A gas injection hole is provided in the wall surface formed at the starting point of the guide surface to penetrate the fixed ring and go upward along the inner wall surface of the fixed ring. A centrifugal fluid milling device characterized by: