JP2024081629A - Wet type bead mill - Google Patents

Abstract

To provide a wet type bead mill that can maintain high dispersion efficiency by preventing a crushing medium from flowing out of a processing chamber during dispersion processing.SOLUTION: A wet type bead mill 1 includes: a processing chamber 2 which stores a mixture of slurry containing a material to be crushed and a crushing medium; an agitation device A which performs distribution processing and/or disintegration processing and/or pulverization processing on the material to be crushed by rotating in the processing chamber 2; and a slurry passage 12 which has an opening in the processing chamber 2 and derives the slurry to the outside of the processing chamber. A baffle 5 is provided in the processing chamber 2 so that a portion of the slurry agitated by the agitation device A generates the flow to the inside of the processing chamber. With this, the flow of the slurry flowing out of the processing chamber A through the slurry passage 12 is mixed with the flow of the slurry to the interior of the processing chamber A, and the outflow of the crushing medium to the outside of the processing chamber A through the slurry passage 12 is prevented.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wet bead mill with excellent dispersion performance.

The present invention also relates to a wet bead mill that can also be used as a grinder or disintegrator.

In a vertical wet bead mill, when the agitator rotates in a simple cylindrical dispersion chamber, the vortex generated by the agitation easily causes the beads, which are the grinding medium, to fly up in the slurry and reach the periphery of the centrifuge device located above the agitator in the dispersion chamber. Depending on the conditions, a large number of these flying beads may remain at the top of the dispersion chamber, causing the so-called bead packing phenomenon, which may ultimately interfere with the normal rotational motion of the centrifuge device and result in abnormal heat generation or abnormal load.

JP 2013-39508 A discloses a media agitation type grinder that can perform stable grinding processing, produce a slurry in which nano-sized particles are dispersed, and does not cause agglomeration of solid particles.

JP 2007-125454 A discloses a high-speed mixing device for mixing and stirring liquids and liquids or powders and liquids, and for atomizing, emulsifying, and dispersing the components. This high-speed mixing device is equipped with a cylindrical mixing vessel having an uneven inner surface, a rotating blade that is concentric with the mixing vessel and has an outer diameter slightly smaller than the inner diameter of the mixing vessel, and a shaft that can rotate forward and reverse at high speed and has the rotating blade at its end. By rotating the shaft at high speed to rotate the rotating blade at high speed, the liquid to be treated that has been introduced into the mixing vessel is mixed while rotating at high speed in a thin cylindrical shape along the uneven inner surface of the mixing vessel.

JP 2013-39508 A JP 2007-125454 A

An object of the present invention is to provide a wet bead mill having excellent dispersion performance by preventing the grinding media from flowing out of the treatment chamber during dispersion treatment and maintaining high dispersion efficiency.
Another object of the present invention is to provide a wet bead mill which can also be used as a grinder or disintegrator.

The wet bead mill of the present invention has a processing chamber that contains a mixture of a slurry containing materials to be crushed and a grinding medium, a stirring device that rotates in the processing chamber to stir the mixture and disperse and/or crush and/or grind the materials to be crushed, and a slurry passage that has an opening in the processing chamber and leads the slurry to the outside of the processing chamber. In this wet bead mill, a baffle is provided in the processing chamber so that a part of the slurry stirred by the stirring device generates a flow toward the inside of the processing chamber, and the baffle mixes the flow of the slurry flowing out of the processing chamber through the slurry passage with the flow of the slurry flowing toward the inside of the processing chamber, thereby preventing the grinding medium from flowing out of the processing chamber through the slurry passage.

The baffle of the wet bead mill of the present invention has a slurry guide surface surrounding the opening of the slurry passage, and this slurry guide surface is characterized in that, near the opening, it is inclined in the opposite direction to the flow direction of the slurry that flows out of the processing chamber through the slurry passage.

The slurry guide surface of the wet bead mill of the present invention can be configured as a concave curved surface.

The slurry guide surface of the wet bead mill of the present invention can also be configured by a conical surface inclined toward the opening and toward the inside of the processing chamber.

The baffle of the wet bead mill of the present invention has a slurry inlet opening on the slurry guide surface and a branch passage having a slurry outlet opening in the middle of the slurry passage, and a second slurry guide surface is formed in this branch passage, and this second slurry guide surface can be inclined in the opposite direction to the flow direction of the slurry flowing out of the processing chamber through the slurry passage near the outlet opening.

The stirring device of the wet bead mill of the present invention has a fin disk facing the slurry guide surface and an end disk facing the bottom surface of the processing chamber, the fin disk has stirring fins extending in a radial direction and protruding toward the slurry guide surface, and the end disk can have stirring fins extending in a radial direction and multiple through holes extending in an axial direction.

The end disk of the wet bead mill of the present invention can have a smaller diameter than the fin disk.

The stirring fins of the end disk of the wet bead mill of the present invention can be formed only on the fin disk side.

The wet bead mill of the present invention also has a processing chamber that contains a mixture of a slurry containing the material to be crushed and a grinding medium, a stirring device that rotates in the processing chamber to stir the mixture and disperse and/or crush and/or grind the material, and a slurry passage that has an opening in the processing chamber and discharges the slurry to the outside of the processing chamber, and is characterized in that a buffer chamber is provided in the processing chamber, the processing chamber and the buffer chamber are connected via the slurry passage, the slurry passage has a slurry inlet in the processing chamber, the slurry passage has a slurry outlet in the buffer chamber, and a grinding medium separation device that separates the grinding medium from the slurry is disposed in the buffer chamber.

In the wet bead mill of the present invention, the buffer chamber is disposed above the processing chamber, the inner surface of the buffer chamber is formed with a cylindrical surface and a truncated cone-shaped surface extending in a mortar shape from the lower end of the cylindrical surface toward the slurry outlet of the slurry passage, the grinding medium separation device is constituted by a centrifugal separator, the centrifugal separator is disposed in a position surrounded by the cylindrical surface of the buffer chamber, and the outer diameter of the upper part of the centrifugal separator can be made larger than the outer diameter of the lower part of the centrifugal separator.

In the wet bead mill of the present invention, the centrifugal separator can be provided with a swastika-shaped slurry passage.

In the wet bead mill of the present invention, the grinding medium separation device can be configured with a gap separator and/or a screen that does not allow the grinding medium to pass through.

The wet bead mill of the present invention also has a processing chamber that contains a mixture of a slurry containing the material to be crushed and a grinding medium, a stirring device that rotates in the processing chamber to stir the mixture and disperse and/or crush and/or grind the material to be crushed, and a slurry passage that has an opening in the processing chamber and leads the slurry to the outside of the processing chamber, and is characterized in that the inner surface of the processing chamber is formed of a cylindrical surface, and a plurality of grooves are formed at predetermined intervals on the cylindrical surface, extending at a predetermined angle with respect to the axial direction of the rotating shaft of the stirring device.

The multiple grooves on the inner surface of the processing chamber of the wet bead mill of the present invention can each have a smoothly curved concave cross-sectional shape.

The multiple grooves on the inner surface of the processing chamber of the wet bead mill of the present invention can each be configured as parallel grooves extending parallel to the axis of the rotating shaft of the stirring device.

The parallel grooves on the inner surface of the processing chamber of the wet bead mill of the present invention can be divided into upper and lower parallel grooves, and the upper and lower parallel grooves can be arranged out of phase with each other.

The multiple grooves on the inner surface of the processing chamber of the wet bead mill of the present invention are each configured as an inclined groove extending at an angle with respect to the axial direction of the rotation shaft of the stirring device, and the inclined grooves can be located in a position where the phase of the lower part of the inclined groove leads the phase of the upper part of the inclined groove along the rotation direction of the stirring device.

The groove on the inner surface of the processing chamber of the wet bead mill of the present invention is configured as a spiral groove that winds around the rotation axis of the stirring device, and the spiral groove can extend from the top to the bottom of the inner surface of the processing chamber along the rotation direction of the stirring device.

According to the wet bead mill of the present invention, the behavior of the grinding media in the treatment chamber can be controlled and the amount of grinding media flowing from the treatment chamber into the buffer chamber can be reduced, thereby obtaining excellent dispersion results.
In addition, according to the wet bead mill of the present invention, the possibility that the grinding media separated from the slurry in the buffer chamber will flow again into a grinding media separation device such as a centrifuge can be reduced, thereby improving the slurry processing capacity.
The wet bead mill of the present invention can also be used as a pulverizer or crusher.

Other features and effects of the wet bead mill of the present invention will become apparent from the following description, which refers to the drawings.

FIG. 1 is a diagram showing the overall configuration of an embodiment of a wet bead mill according to the present invention. FIG. 2 is a vertical sectional view of a main part of the wet bead mill of FIG. FIG. 3 is a bottom view of the wet bead mill of FIG. 4A is a plan view of a bottom plate of the wet bead mill of FIG. 2, and FIG. 4B is a cross-sectional view of the bottom plate. 5A is a cross-sectional view of the inner wall member of the processing chamber, FIG. 5B is a perspective view of the cylindrical surface constituting the inner surface of the inner wall member, and FIG. 5C is a bottom view of the inner wall member. 6(A) is a top view of the fin disk of the agitator, FIG. 6(B) is a side view including a partial cross section of the same fin disk, and FIG. 6(C) is a bottom view of the same fin disk. 7A is a top view of an end disk of the mixing device, FIG. 7B is a vertical sectional view of the end disk, and FIG. 7C is a bottom view of the end disk. FIG. 8A is a vertical cross-sectional view of the large collar, and FIG. 8B is a bottom view of the large collar. 9A is a top view of the baffle, FIG. 9B is a vertical cross-sectional view of the same baffle, and FIG. 9C is a bottom view of the same baffle. FIG. 10 is a longitudinal cross-sectional view of a modified embodiment of the baffle. FIG. 11A is a vertical cross-sectional view of the inner wall member of the buffer chamber, and FIG. 11B is a bottom view of the inner wall member. FIG. 12A is a plan view of the top plate of the buffer chamber, and FIG. 12B is a cross-sectional view of the same top plate. 13A is a top view of an upper member of the centrifugal separator, FIG. 13B is a vertical sectional view of the same member, and FIG. 13C is a bottom view of the same member. 14(A) is a top view of a lower member of the centrifugal separator, FIG. 14(B) is a vertical sectional view of the lower member, and FIG. 14(C) is a bottom view of the lower member. Figure 15(A) is a top view of a small collar, Figure 15(B) is a longitudinal sectional view of the small collar, and Figure 15(C) is a plan view showing a swastika-shaped groove formed on the top surface of the small collar and its positional relationship with the lower member of a centrifugal separator. FIG. 16 is a schematic diagram of a centrifugal separator blade showing the form of a slurry flow path formed in the centrifugal separator. FIG. 17 is a photograph of the rotating shaft extending downward from the top plate of the wet bead mill of FIG. Figure 18 is a photograph showing the state in which the agitator, collar (large), centrifugal separator, and collar (small) are attached to the rotating shaft of Figure 17. The collar (small) cannot be seen because it is located inside the centrifugal separator. FIG. 19(A) is a cross-sectional view of another embodiment of the inner wall member of the processing chamber, FIG. 19(B) is a perspective view of the cylindrical surface constituting the inner surface of the inner wall member, and FIG. 19(C) is a bottom view of the inner wall member. FIG. 20 is a cross-sectional view of still another embodiment of the inner wall member of the processing chamber. FIG. 21 is a perspective view of a cylindrical surface of an inner wall member of a processing chamber in which a spiral groove is formed. FIG. 22 is a vertical cross-sectional view of a processing chamber showing another embodiment of the baffle. FIG. 23 is a vertical cross-sectional view of a processing chamber showing still another embodiment of the baffle. FIG. 24A is a vertical sectional view of a processing chamber showing still another embodiment of the baffle, and FIG. 24B is an enlarged view of a main portion of FIG. 24A. FIG. 25 is a vertical cross-sectional view of a processing chamber showing still another embodiment of the baffle. FIG. 26 is a vertical cross-sectional view of a processing chamber showing still another embodiment of the baffle. FIG. 27 is a vertical cross-sectional view of a processing chamber showing still another embodiment of the baffle. FIG. 28 is a vertical cross-sectional view of the processing chamber showing the stirring device equipped with a small diameter end disk. 29(A) is a top view of the small diameter end disk, FIG. 29(B) is a cross-sectional view of the small diameter end disk, and FIG. 29(C) is a bottom view of the small diameter end disk. FIG. 30 is a table showing the dispersion results when barium titanate (primary particle diameter: about 150 nm) was dispersed using the bead mill DAM-1 of the present invention and a conventional machine. FIG. 31 is a table showing the results of sedimentation velocity distribution when dispersion of barium titanate (primary particle diameter: about 150 nm) was performed using the bead mill DAM-1 of the present invention and a conventional machine. FIG. 32 is a table showing the relationship between D50 and residence time and the relationship between viscosity and residence time when dispersion of barium titanate (with binder) was performed using the bead mill DAM-1 of the present invention and a conventional machine. FIG. 33 is a table showing the relationship between D50 and residence time when dispersion of titanium oxide (primary particle diameter: 15 nm) was performed using the bead mill DAM-1 of the present invention and a conventional machine. FIG. 34 is a table showing the relationship between D50 and residence time when dispersion of titanium oxide (primary particle diameter: 15 nm) was performed using the bead mill DAM-1 of the present invention and a conventional machine. FIG. 35 is a table outlining an example of the specifications of the bead mill of the present invention.

We will explain about the wet bead mill, which has excellent dispersion capabilities.

The wet bead mill 1 has a processing chamber 2, a buffer chamber 3 arranged above the processing chamber 2, and a baffle 5 arranged between the processing chamber 2 and the buffer chamber 3 and having a circular central hole 4. The wet bead mill 1 has a rotating shaft 6 that penetrates the processing chamber 2 in the vertical direction and extends into the buffer chamber 2 through the central hole 4, and the rotating shaft 6 is connected to the rotating shaft 10 of an electric motor (not shown) via a pulley 7, a belt 8, and a pulley 9. An annular slurry passage 12 is defined between the central hole 4 of the baffle 5 and the outer circumferential surface of the collar (large) 11. The processing chamber 2 and the buffer chamber 3 are connected through the annular slurry passage 12. The part of the rotating shaft 6 that extends above the buffer chamber 3 is composed of a circular cross-sectional portion 6a having a circular cross section, and the circular cross-sectional portion 6a of the rotating shaft 6 is rotatably supported by radial bearings 13, 14, and 15. A mechanical seal 16 that seals the rotating shaft 6 is fitted to the circular cross-sectional portion 6a of the rotating shaft 6. The mechanical seal 16 seals the buffer chamber 3 and the processing chamber 2. The portion of the rotating shaft 6 below the circular cross-sectional portion 6a is composed of a rectangular cross-sectional portion 6b having a rectangular cross section, and the rectangular cross-sectional portion 6b has an octagonal cross-sectional shape consisting of four long sides and four short sides. Figure 17 is a photograph of the rectangular cross-sectional portion 6b of the rotating shaft 6. Four slurry inlets 6c extending in the radial direction of the rotating shaft 6 are opened in the rectangular cross-sectional portion 6b, and these slurry inlets 6c communicate with a slurry flow path 6d formed along the axis of the rotating shaft 6. The slurry flow path 6d extends to the upper end 6e of the rotating shaft 6 and communicates with the processing chamber 2 via an external pipe 17, a pump 18, an external pipe 19, and a sanitary check valve 20.

The processing chamber 2 of the wet bead mill 1 is defined by a baffle 5, an inner wall member 21, and a bottom plate 22. As shown in FIG. 9, the baffle 5 is a generally disk-shaped member having a central hole 4. A truncated cone-shaped annular tapered surface 5b that is continuous with the central hole 4 is formed in the center of the upper surface 5a of the baffle 5, and an input hole 5c for the material to be processed is formed on the side of the annular tapered surface 5b. As shown in FIG. 2, the truncated cone-shaped annular tapered surface 5b is continuous with the truncated cone-shaped annular tapered surface 23a of the inner wall member 23 of the buffer chamber 3 described later, and forms a truncated cone-shaped annular tapered surface 24 that is continuous with the slurry passage 12 at the bottom of the buffer chamber 3. A circular concave curved surface 5e is formed on the back surface 5d of the baffle 5 at a position surrounding the central hole 4. The annular concave curved surface 5e is a slurry guide surface that generates a flow of slurry toward the inside of the processing chamber 2, as shown by the arrow in FIG. 2, of a part of the slurry stirred by the stirring device A rotating inside the processing chamber 2. This slurry guide surface, i.e., the annular concave curved surface 5e, mixes the flow of slurry flowing from the processing chamber 2 to the buffer chamber 3 through the annular slurry passage 12 with the flow of slurry toward the inside of the processing chamber 2, as shown by the arrow in FIG. 2, and prevents the grinding medium (not shown) such as zirconia beads inside the processing chamber 2 from flowing through the slurry passage 12 to the buffer chamber 3. To achieve this purpose, the slurry guide surface, i.e., the concave curved surface 5e, must be inclined in the opposite direction to the flow direction of the slurry flowing from the processing chamber 2 to the buffer chamber 3 through the slurry passage 12 near the central hole 4. Therefore, this slurry guide surface can be constituted by a conical surface inclined toward the inside of the processing chamber 2 toward the central hole 4 that constitutes the opening of the baffle 5.

Figure 10 is a cross-sectional view of a modified baffle. The baffle 5 in Figure 10 is composed of one member, but the baffle 50 in Figure 10 is composed of a lower member 50a and an upper member 50b integrated with a seal material 50c in between. The lower member 50a has a central hole 50d and a slurry guide surface 50e, and the annular concave curved surface 50e constituting the slurry guide surface changes its cross-sectional shape continuously. This allows the mixing position of the slurry flow toward the inside of the processing chamber 2 and the slurry flow flowing from the processing chamber 2 to the buffer chamber 3 through the slurry passage 12 to be continuously changed in the axial direction of the central hole 50d, and a slurry mixing area extending in the axial direction of the central hole 50d can be generated. The upper member 50b of the baffle 50 has a truncated cone-shaped annular tapered surface 50e that continues to the central hole 50d of the lower member 50a. As shown in FIG. 2, the truncated cone-shaped annular tapered surface 50b is continuous with the truncated cone-shaped annular tapered surface 23a of the inner wall member 23 of the buffer chamber 3 described later, and forms a truncated cone-shaped annular tapered surface 24 that is continuous with the slurry passage 12 at the bottom of the buffer chamber 3. By constructing the lower member 50a and the upper member 50b of the baffle 50 from separate members, the lower member 50a and the upper member 50b can be easily processed, and in particular, the shape of the slurry guide surface 50e can be changed in various ways.

As shown in FIG. 5, the inner wall member 21 of the processing chamber 2 is a cylindrical member as a whole. The inner surface 21a of the inner wall member 21 is also composed of a cylindrical surface, and 10 grooves 21b extending in the vertical direction are formed at regular intervals on the inner surface 21a. Each of these grooves 21b is a parallel groove extending parallel to the rotation axis of the rotating shaft 6. Each of these grooves 21b has a cross-sectional shape that is smoothly curved in a concave shape. As shown in FIG. 4, the bottom plate 22 of the processing chamber 2 is a circular plate. A circular slurry return hole 22a is formed in the center of the bottom plate 22, and the external piping 19 is connected to this slurry return hole 22a via a sanitary check valve 20. The outside of the inner wall member 21 of the processing chamber 2 is covered by a water jacket 21c for cooling, as shown in FIG. 2. Note that FIG. 3 is a view of the bottom plate 1a of the wet bead mill 1 viewed from below the wet bead mill 1.

The buffer chamber 3 is provided above the treatment chamber 2. The buffer chamber 3 is defined by the inner wall member 23, the top plate 25, and the upper surface 5a of the baffle 5. As shown in FIG. 11, the inner surface of the inner wall member 23 has a truncated cone-shaped annular tapered surface 23a and a cylindrical surface 23b, and a circular opening 23c is formed at the lower end of the truncated cone-shaped annular tapered surface 23a. As described above, the truncated cone-shaped annular tapered surface 23a of the inner wall member 23 smoothly continues to the truncated cone-shaped annular tapered surfaces 5b, 50b of the baffles 5, 50b, forming a truncated cone-shaped annular tapered surface 24 that continues to the slurry passage 12 at the bottom of the buffer chamber 3 (see FIGS. 1 and 2). As shown in FIG. 12, the top plate 25 is composed of a disk-shaped member as a whole, and a circular through hole 25a is formed in the center. As shown in Figures 2 and 17, the lower end of the mechanical seal 16 is located in the circular through hole 25a, and the rectangular cross-sectional portion 6b of the rotating shaft 6 protrudes downward from the center of the mechanical seal 16.

The agitation device A is composed of a fin disk 26 and an end disk 27. The fin disk 26 and the end disk 27 are fitted to the square cross-sectional portion 6b of the rotating shaft 6 and placed in the treatment chamber 2. As shown in FIG. 6, the fin disk 26 has a disk-like shape as a whole, and four agitation fins 26b are formed on the upper surface 26a of the fin disk 26. These agitation fins 26b extend in the radial direction of the fin disk 26 and protrude at an angle toward the slurry guide surfaces 5e and 50e of the baffle 5. A fitting hole 26c with the square cross-sectional portion 6b of the rotating shaft 6 is formed in the center of the fin disk 26, and an O-ring mounting groove 25d is formed on the upper surface 25a of the fin disk 26 at a position surrounding the fitting hole 26c. As shown in FIG. 7, the end disk 27 has four agitation fins 27c extending in the radial direction on its upper surface 27a and lower surface 27b. Furthermore, in the area between the stirring fins 27c of the end disk 27, a plurality of through holes 27d are formed that open to the upper surface 27a and the lower surface 27b of the end disk 27. A fitting hole 27e for fitting with the rectangular cross-sectional portion 6b of the rotating shaft 6 is formed in the center of the end disk 27, and an O-ring mounting groove 27f is formed in the upper surface 27a of the end disk 27 at a position surrounding the fitting hole 27e. Reference number 27g indicates an insertion hole for a fixing bolt 28 that screws into a screw hole formed in the lower end surface of the rectangular cross-sectional portion 6b of the rotating shaft 6. The fixing bolt 28 fixes the stirring device A, the collar (large) 11, and the centrifugal separator B to the rectangular cross-sectional portion 6b of the rotating shaft 6.

Figure 8 shows the large collar 11 that is interposed between the agitator A and the centrifugal separator B. The large collar 11 is made of a cylindrical member overall, with a circular through hole 11a formed along its axis. An O-ring mounting groove 11c is formed on the lower end surface 11b of the large collar 11 at a position surrounding the through hole 11a. The rectangular cross-sectional portion 6b of the rotating shaft 6 is inserted into the circular through hole 11a.

Figures 13 to 16 show the components of the centrifuge B arranged in the buffer chamber 3. The centrifuge B is located above the large collar 11 and is arranged at a position facing the cylindrical surface 23b of the inner wall member 23 of the buffer chamber 3. The centrifuge B is composed of an upper member 29, a lower member 30, and a small collar 31. As shown in Figure 13, a central hole 29a into which the rectangular cross-sectional portion 6b of the rotating shaft 6 is fitted is formed in the center of the upper member 29, and an annular convex portion 29c surrounding the central hole 29a is formed on the upper surface 29b of the upper member 20. An annular convex portion 29e surrounding the central hole 29a is formed on the lower surface 29d of the upper member 29, and four notches 29f are formed in the annular convex portion 29e at positions corresponding to the four slurry inlet ports 6c of the rotating shaft 6. On the lower surface 29d of the upper member 29, twelve centrifugal vanes 29g are formed at a fixed distance from the annular protrusion 29e. As shown in Fig. 14, a central hole 30a into which the rectangular cross-sectional portion 6b of the rotating shaft 6 is fitted is formed in the center of the lower member 30, and an O-ring mounting groove 30c is formed on the upper surface 30b of the lower member 30 so as to surround the central hole 30a. On the upper surface 30b of the lower member 30, twelve centrifugal vanes 30d are also formed at a fixed distance from the O-ring mounting groove 30c. The lower surface 30e of the lower member 30 consists of a truncated cone-shaped annular tapered surface 30f and a flat surface 30g parallel to the upper surface 30b. As shown in Fig. 16, the centrifugal vanes 29g of the upper member 29 and the centrifugal vanes 30d of the lower member 30 are arranged so that they draw an arc a with a constant radius r centered on a point R on an imaginary reference circle S inside these members 29 and 30, and form a centrifugal passage P between the adjacent centrifugal vanes 29g and 30d along this arc a. As shown in Fig. 18, the upper member 29 and the lower member 30 are combined so that the centrifugal vanes 29g of the upper member 29 and the centrifugal vanes 30d of the lower member 30 abut one-to-one, and a centrifugal passage P is defined between the two adjacent centrifugal vanes 29g and the two adjacent centrifugal vanes 30d. Figs. 15(A) and (B) show a collar (small) 31 arranged between the upper member 29 and the lower member 30. The collar (small) 31 is made of a cylindrical member as a whole, and a through hole 31a with a circular cross section through which the rectangular cross section portion 6b of the rotating shaft 6 is inserted is formed in the center. An O-ring mounting groove 31b is formed in the through hole 31a. The upper surface 31c of the small collar 31 is flat, and the lower surface 31d of the small collar 31 is also flat. Figure 15 (C) shows an embodiment in which a swastika-shaped groove 32c is formed on the flat upper surface 32a of the small collar 32 to correspond to the four slurry inlets 6c of the rotating shaft 6, and further shows the positional relationship between the swastika-shaped groove 32c of the small collar 32 and the centrifugal blade 30d of the lower member 30. The presence of the swastika-shaped groove 32c prevents the grinding medium (not shown) such as zirconia beads that has not been centrifuged in the centrifugal separation passage P and has reached the vicinity of the small collar 32 from entering the slurry flow passage 6d from the slurry inlet 6c of the rotating shaft 6.

The reason why the outer diameter of the upper member 29 of the centrifuge device B is larger than the outer diameter of the lower member 30 is that by reducing the gap between the upper member 29 and the cylindrical surface 23b of the buffer chamber 3, the mixing force in the upper part of the buffer chamber 3 is increased and the grinding medium that flows into the buffer chamber 3 is prevented from remaining in the upper part of the buffer chamber 3.
The reason why the annular tapered surface 24 of a truncated cone shape continuing to the slurry passage 12 is formed at the bottom of the buffer chamber 3 is as follows: The slurry flow ascending from the treatment chamber 2 to the buffer chamber 3 through the slurry passage 12 is a swirling flow along the circumferential surface of the collar (large) 11, and as this swirling flow ascends along the annular tapered surface 24 whose upper part is expanded, the speed of the swirling flow gradually decreases and its pressure increases. Therefore, the grinding media in the swirling flow settles due to its own weight and the pressure difference between the upper and lower parts of the annular tapered surface 24, and moves toward the slurry passage 12. Therefore, when the wet bead mill 1 is stopped, the grinding media is expected to reach the slurry passage 12 along the annular tapered surface 24 and return to the treatment chamber 2 due to its own weight without being retained in the buffer chamber 3.
The reason for forming a plurality of grooves on the inner surface of the processing chamber 2 is that turbulence occurs near the grooves, and this turbulence increases the interaction between the grinding media, improving the grinding efficiency. In particular, by making each of these grooves into a smoothly curved concave cross-sectional shape, the flow direction can be changed without significantly slowing down the circumferential speed, so that the flow collides with the circumferential flow near the outlet of the groove, increasing the interaction between the grinding media. In addition, the speed of the grinding media decreases due to the collision of the flow near the groove, so that the grinding media can be prevented from flying up. Furthermore, the presence of the grooves increases the area of the inner surface of the processing chamber, so the amount of work performed between the grinding media and the inner surface of the processing chamber increases, improving the grinding efficiency. Furthermore, the smoothly curved concave cross-sectional shape is not difficult to process into difficult-to-process materials such as ceramics, making it possible to use difficult-to-process materials for the inner wall member of the processing chamber. Furthermore, the smoothly curved concave cross-sectional shape is superior to other shapes in terms of corner cleanability, resistance to wear, and ease of processing.

Figures 19 to 21 show other embodiments of the inner wall member 21 of the processing chamber 2. Figure 19 shows an embodiment in which the grooves on the inner surface 21Aa of the inner wall member 21A are divided into upper grooves 21Ab and lower grooves 21Ac, and the phases of these grooves are shifted. Figure 20 shows an embodiment in which the grooves 21Bb on the inner surface 21Ba of the inner wall member 21B are inclined, and these inclined grooves 21Ba are in a position where the phase of the lower portion is more advanced than the phase of the upper portion along the rotation direction of the stirring device A. This allows the grinding medium to be guided downward in the processing chamber 2. Figure 21 shows an embodiment in which the grooves 21Cb are formed in a spiral shape on the inner surface 21Ca of the inner wall member, and the spiral grooves 21Cb extend from the upper portion of the processing chamber 2 to the lower portion of the inner surface 21Ca along the rotation direction of the stirring device A. This allows the grinding medium to be guided downward in the processing chamber 2.

22 to 27 show modifications of the baffle 5. FIG.
The baffle 5A in Fig. 22 has a flat surface on the side of the buffer chamber 3, and because the inner surface of the buffer chamber 3 is cylindrical from top to bottom, there is a risk that the grinding media that flows into the buffer chamber 3 will remain inside the buffer chamber 3. However, if the slurry passage 12A is used as a gap separator, it is possible to prevent the grinding media from flowing into the buffer chamber 3. It is also possible to install a screen at the outlet of the slurry passage 12A on the buffer chamber 3 side to prevent the grinding media from flowing out. The rest of the configuration is the same as that of the wet bead mill 1 in Fig. 2.
The baffle 5B in Fig. 23 is an embodiment in which the slurry passage 12B is used as a gap separator. The other configurations are the same as those of the wet bead mill 1 in Fig. 2.
24 has a slurry inlet opening O1 on its slurry guide surface, a branch passage BR having a slurry outlet opening O2 in its slurry passage 12C, and a second slurry guide surface is formed in the branch passage BR, which is inclined in the opposite direction to the flow direction of the slurry flowing out of the treatment chamber 2 through the slurry passage 12. The other configurations are the same as those of the wet bead mill 1 in FIG.
25 is characterized in that the slurry guide surface extends linearly toward the slurry passage 12D in the cross section of the baffle 5D in the figure. The other configurations are the same as those of the wet bead mill 1 in FIG.
The baffle 5E in Fig. 26 is characterized in that another grinding disk EX is provided in the middle of the slurry passage 12E, and a slurry guide surface is also provided in the treatment chamber 2E that houses the grinding disk EX. In this embodiment, both the slurry guide surfaces of the treatment chamber 2 and the treatment chamber 2E extend linearly toward the slurry passage 12E. The rest of the configuration is the same as that of the wet bead mill 1 in Fig. 2.
The baffle 5F in Fig. 27 is characterized in that a slurry inflow space SP is formed above the slurry guide surface of the treatment chamber 2E, and a slurry guide surface extending linearly toward the slurry passage 12E is also provided in the slurry inflow space SP. The other configurations are the same as those of the wet bead mill 1 in Fig. 2.

Figure 28 shows a modified version of the agitator A of the wet bead mill 1. The fin disk 26A of the agitator Aa shown in this figure is similar to the fin disk 26 in Figure 6, but is characterized in that the end disk 27A has a smaller diameter than the fin disk 26A, and further, the agitator fins 27Ac of the end disk 27A are formed only on the side of the fin disk 26A. This effectively prevents the grinding medium from being lifted up to the top of the processing chamber 2. The rest of the configuration is the same as that of the wet bead mill 1 in Figure 2.

Figure 30 is a table showing the results of dispersion of barium titanate (primary particle diameter: about 150 nm) using the bead mill DAM-1 of the present invention and a conventional machine. With regard to D50, the progress is slower with DAM-1, but it is shown that it can be finely divided to the same level as with the conventional machine. With regard to sharpness (D99-D1)/D50, it is shown that DAM-1 has a sharper particle size distribution. And with regard to viscosity transition, it is shown that DAM-1 has a more gentle viscosity increase. Overall, DAM-1 has a sharp particle size distribution, which means that the generation of fine particles is suppressed and coarse particles are reduced. Furthermore, DAM-1 has a gentle viscosity increase, which suggests that the generation of fine particles is suppressed. This means that DAM-1 suppresses the generation of fine particles and enables uniform dispersion.

Figure 31 is a table showing the settling velocity distribution results when dispersing barium titanate (primary particle diameter: approximately 150 nm) using the bead mill DAM-1 of the present invention and a conventional machine. The settling velocity distribution results show that with the conventional machine, coarse particles (which may be both untreated particles and agglomerated particles) remain indefinitely, whereas with DAM-1, a sharp distribution is achieved in 17 minutes, after which re-agglomeration occurs. Although appropriate condition settings are required, it can be said that DAM-1 provides a more uniform dispersion.

Figure 32 is a table showing the relationship between D50 and residence time, and the relationship between viscosity and residence time when dispersing barium titanate (with binder) using the bead mill DAM-1 of the present invention and a conventional machine. From both tables in the figure, it can be seen that the progress of microparticulation is faster with DAM-1, and that processing is performed without an increase in viscosity. It can also be seen that while a significant increase in viscosity occurs when the speed is changed to 11 m/s with the conventional machine, there is no increase in viscosity even at 11 m/s with DAM-1. This shows that the DAM-1 can perform high-quality dispersion with suppressed generation of fine particles.

Figure 33 is a table showing the relationship between D50 and residence time when dispersing titanium oxide (primary particle diameter: 15 nm) using the bead mill DAM-1 of the present invention and a conventional machine. It can be seen from the table that even in a peripheral speed range where agglomeration occurs with a conventional machine, the DAM-1 allows dispersion without agglomeration. Therefore, the DAM-1 makes it possible to perform high-quality dispersion with suppressed generation of fine particles.

Figure 34 is a table comparing the grinding performance when grinding calcium carbonate with the bead mill DAM-1 of the present invention and a conventional machine. The main objective of the present invention is to provide a bead mill that enables high-quality dispersion, and each table in the figure shows that the bead mill of the present invention can also achieve grinding performance equivalent to that of a conventional machine depending on the peripheral speed setting.

Figure 35 is a table outlining an example of the specifications of the bead mill DAM-1 of the present invention.

The bead mill of the present invention is a bead mill that allows for high-quality dispersion, and depending on the peripheral speed setting, the bead mill of the present invention can also achieve grinding performance equivalent to that of conventional machines.

1 Wet bead mill 2 Treatment chamber 3 Buffer chamber 5 Baffle 12 Slurry passage

The treatment chamber 2 of the wet bead mill 1 is defined by a baffle 5, an inner wall member 21, and a bottom plate 22. As shown in FIG. 9, the baffle 5 is a generally disk-shaped member having a central hole 4. A truncated cone-shaped annular tapered surface 5b is formed in the center of the upper surface 5a of the baffle 5, which is continuous with the central hole 4, and an input hole 5c for the material to be treated is formed on the side of the annular tapered surface 5b. As shown in FIG. 2, the truncated cone-shaped annular tapered surface 5b is continuous with a truncated cone-shaped annular tapered surface 23a of the inner wall member 23 that defines the inner surface 3a of the buffer chamber 3 described later, and forms a truncated cone-shaped annular tapered surface 24 at the bottom of the buffer chamber 3 that is continuous with the slurry passage 12. An annular concave curved surface 5e is formed on the back surface 5d of the baffle 5 at a position surrounding the central hole 4. The annular concave curved surface 5e is a slurry guide surface that generates a slurry flow toward the inside of the treatment chamber 2, as shown by the arrow in Fig. 2, of a part of the slurry stirred by the stirring device A rotating inside the treatment chamber 2. The slurry guide surface, i.e., the annular concave curved surface 5e, mixes the slurry flow flowing from the treatment chamber 2 to the buffer chamber 3 through the annular slurry passage 12 with the slurry flow toward the inside of the treatment chamber 2, as shown by the arrow in Fig. 2, and prevents the grinding medium (not shown) such as zirconia beads inside the treatment chamber 2 from flowing out to the buffer chamber 3 through the slurry passage 12. To achieve this purpose, the slurry guide surface, i.e., the concave curved surface 5e, must be inclined in the opposite direction to the flow direction of the slurry flowing from the treatment chamber 2 to the buffer chamber 3 through the slurry passage 12 near the central hole 4. Therefore, the slurry guide surface can be constituted by a conical surface inclined toward the inside of the treatment chamber 2 toward the central hole 4 that constitutes the opening of the baffle 5.

Fig. 10 is a cross-sectional view of a modified baffle. While the baffle 5 in Fig. 9 is composed of one member, the baffle 50 in Fig. 10 is composed of a lower member 50a and an upper member 50b integrated with a seal material 50c sandwiched therebetween. The lower member 50a has a central hole 50d and a slurry guide surface 50e, and the annular concave curved surface constituting the slurry guide surface 50e changes its cross-sectional shape continuously. This allows the mixing position of the slurry flow toward the inside of the processing chamber 2 and the slurry flow flowing from the processing chamber 2 to the buffer chamber 3 through the slurry passage 12 to be continuously changed in the axial direction of the central hole 50d, thereby generating a slurry mixing region extending in the axial direction of the central hole 50d. The upper member 50b of the baffle 50 has a truncated cone-shaped annular tapered surface 50f continuing to the central hole 50d of the lower member 50a. 2, the frusto-conical annular tapered surface 50b is continuous with a frusto-conical annular tapered surface 23a (see FIG. 11) of the inner wall member 23 of the buffer chamber 3 described below, and forms a frusto-conical annular tapered surface 24 which is continuous with the slurry passage 12 at the bottom of the buffer chamber 3. By constructing the lower member 50a and the upper member 50b of the baffle 50 from separate members, the lower member 50a and the upper member 50b can be easily machined, and in particular, the shape of the slurry guide surface 50e can be changed in various ways.

The buffer chamber 3 is provided above the treatment chamber 2. The buffer chamber 3 is defined by an inner wall member 23, a top plate 25, and an upper surface 5a of the baffle 5. As shown in FIG. 11, the inner surface of the inner wall member 23 has a truncated cone-shaped annular tapered surface 23a and a cylindrical surface 23b, and a circular opening 23c is formed at the lower end of the truncated cone-shaped annular tapered surface 23a. As described above, the truncated cone-shaped annular tapered surface 23a of the inner wall member 23 smoothly continues to the truncated cone-shaped annular tapered surfaces 5b, 50f of the baffles 5, 50, forming a truncated cone-shaped annular tapered surface 24 at the bottom of the buffer chamber 3 that continues to the slurry passage 12 (see FIGS. 1 and 2). As shown in FIG. 12, the top plate 25 is composed of a disk-shaped member as a whole, and a circular through hole 25a is formed in the center. As shown in FIGS. 2 and 17, the lower end of the mechanical seal 16 is positioned in the circular through hole 25a, and the square cross-sectional portion 6b of the rotating shaft 6 protrudes downward from the center of the mechanical seal 16.

As shown in Figures 1, 2 and 18, the agitation device A is composed of a fin disk 26 and an end disk 27. The fin disk 26 and the end disk 27 are fitted to the rectangular cross-sectional portion 6b of the rotating shaft 6 and are arranged in the treatment chamber 2. As shown in Figure 6, the fin disk 26 is generally disk-shaped, and four agitation fins 26b are formed on the upper surface 26a of the fin disk 26. These agitation fins 26b extend in the radial direction of the fin disk 26 and protrude while inclining toward the slurry guide surfaces 5e and 50f of the baffles 5 and 50. A fitting hole 26c for fitting with the rectangular cross-sectional portion 6b of the rotating shaft 6 is formed in the center of the fin disk 26, and an O-ring mounting groove 26d is also formed on the upper surface 26a of the fin disk 26 at a position surrounding the fitting hole 26c. As shown in Fig. 7, the end disk 27 has four stirring fins 27c extending in the radial direction formed on its upper surface 27a and lower surface 27b. Furthermore, a plurality of through holes 27d opening on the upper surface 27a and lower surface 27b of the end disk 27 are formed in the area between the stirring fins 27c of the end disk 27. A fitting hole 27e for fitting with the rectangular cross-sectional portion 6b of the rotating shaft 6 is formed in the center of the end disk 27, and an O-ring mounting groove 27f is formed in the upper surface 27a of the end disk 27 at a position surrounding the fitting hole 27e. Reference numeral 27g indicates an insertion hole for a fixing bolt 28 that is screwed into a screw hole formed in the lower end surface of the rectangular cross-sectional portion 6b of the rotating shaft 6. The fixing bolt 28 fixes the stirring device A, the collar (large) 11, and the centrifugal separator B to the rectangular cross-sectional portion 6b of the rotating shaft 6.

13 to 16 show components of the centrifugal separator B arranged in the buffer chamber 3. The centrifugal separator B is located above the large collar 11, and is arranged at a position facing the cylindrical surface 23b of the inner wall member 23 of the buffer chamber 3. The centrifugal separator B is composed of an upper member 29, a lower member 30, and a small collar 31. As shown in FIG. 13, a central hole 29a into which the rectangular cross-sectional portion 6b of the rotating shaft 6 is fitted is formed in the center of the upper member 29, and an annular convex portion 29c surrounding the central hole 29a is formed on the upper surface 29b of the upper member 29. An annular convex portion 29e surrounding the central hole 29a is formed on the lower surface 29d of the upper member 29, and four notches 29f are formed in the annular convex portion 29e at positions corresponding to the four slurry inlet ports 6c of the rotating shaft 6. On the lower surface 29d of the upper member 29, twelve centrifugal vanes 29g are formed at a fixed distance from the annular protrusion 29e. As shown in Fig. 14, a central hole 30a into which the rectangular cross-sectional portion 6b of the rotating shaft 6 is fitted is formed in the center of the lower member 30, and an O-ring mounting groove 30c is formed on the upper surface 30b of the lower member 30 so as to surround the central hole 30a. On the upper surface 30b of the lower member 30, twelve centrifugal vanes 30d are also formed at a fixed distance from the O-ring mounting groove 30c. The lower surface 30e of the lower member 30 consists of a truncated cone-shaped annular tapered surface 30f and a flat surface 30g parallel to the upper surface 30b. As shown in Fig. 16, the centrifugal vanes 29g of the upper member 29 and the centrifugal vanes 30d of the lower member 30 are arranged so that they draw an arc a with a constant radius r centered on a point R on an imaginary reference circle S inside these members 29 and 30, and form a centrifugal passage P between the adjacent centrifugal vanes 29g and 30d along this arc a. As shown in Fig. 18, the upper member 29 and the lower member 30 are combined so that the centrifugal vanes 29g of the upper member 29 and the centrifugal vanes 30d of the lower member 30 abut one-to-one, and a centrifugal passage P is defined between the two adjacent centrifugal vanes 29g and the two adjacent centrifugal vanes 30d. Figs. 15(A) and (B) show a collar (small) 31 arranged between the upper member 29 and the lower member 30. The collar (small) 31 is made of a cylindrical member as a whole, and a through hole 31a with a circular cross section through which the rectangular cross section portion 6b of the rotating shaft 6 is inserted is formed in the center. An O-ring mounting groove 31b is formed in the through hole 31a. The upper surface 31c of the small collar 31 is flat, and the lower surface 31d of the small collar 31 is also flat. Fig. 15(C) shows an embodiment in which a gill-shaped groove 32c is formed in the flat upper surface 32a of the small collar 32 to correspond to the four slurry inlet ports 6c of the rotating shaft 6, and further shows the positional relationship between the gill-shaped groove 32c of the small collar 32 and the centrifugal blade 30d of the lower member 30. The presence of the gill-shaped groove 32c prevents the grinding medium (not shown) such as zirconia beads that has not been centrifuged in the centrifugal separation passage P and has reached the vicinity of the small collar 32 from entering the slurry flow passage 6d from the slurry inlet port 6c of the rotating shaft 6.

As shown in Figures 2 and 18, the reason why the outer diameter of the upper member 29 of the centrifugal separator B is larger than the outer diameter of the lower member 30 is that by reducing the gap between the upper member 29 and the cylindrical surface 23b of the buffer chamber 3, the stirring force in the upper part of the buffer chamber 3 is increased and the grinding medium that has flowed into the buffer chamber 3 is prevented from remaining in the upper part of the buffer chamber 3.
The reason why the annular tapered surface 24 of a truncated cone shape continuing to the slurry passage 12 is formed at the bottom of the buffer chamber 3 is as follows: The slurry flow ascending from the treatment chamber 2 to the buffer chamber 3 through the slurry passage 12 is a swirling flow along the circumferential surface of the collar (large) 11, and as this swirling flow ascends along the annular tapered surface 24 whose upper part is expanded, the speed of the swirling flow gradually decreases and its pressure increases. Therefore, the grinding media in the swirling flow settles due to its own weight and the pressure difference between the upper and lower parts of the annular tapered surface 24, and moves toward the slurry passage 12. Therefore, when the wet bead mill 1 is stopped, the grinding media is expected to reach the slurry passage 12 along the annular tapered surface 24 and return to the treatment chamber 2 due to its own weight without being retained in the buffer chamber 3.
The reason for forming a plurality of grooves on the inner surface of the processing chamber 2 is that turbulence occurs near the grooves, and this turbulence increases the interaction between the grinding media, improving the grinding efficiency. In particular, by making each of these grooves into a smoothly curved concave cross-sectional shape, the flow direction can be changed without significantly slowing down the circumferential speed, so that the flow collides with the circumferential flow near the outlet of the groove, increasing the interaction between the grinding media. In addition, the speed of the grinding media decreases due to the collision of the flow near the groove, so that the grinding media can be prevented from flying up. Furthermore, the presence of the grooves increases the area of the inner surface of the processing chamber, so that the amount of work performed between the grinding media and the inner surface of the processing chamber increases, improving the grinding efficiency. Furthermore, the smoothly curved concave cross-sectional shape is not difficult to process into difficult-to-process materials such as ceramics, making it possible to use difficult-to-process materials for the inner wall member of the processing chamber. Furthermore, the smoothly curved concave cross-sectional shape is superior to other shapes in terms of corner cleanability, resistance to wear, and ease of processing.

19 to 21 show other embodiments of the inner wall member 21 of the processing chamber 2. FIG. 19 shows an embodiment in which the grooves on the inner surface 21Aa of the inner wall member 21A are divided into an upper groove 21Ab and a lower groove 21Ac, and the phases of these grooves are shifted. FIG. 20 shows an embodiment in which the grooves 21Bb on the inner surface 21Ba of the inner wall member 21B are inclined, and the inclined grooves 21Bb are located at a position where the phase of the lower portion is more advanced than the phase of the upper portion along the rotation direction of the stirring device A. This allows the grinding medium to be guided downward in the processing chamber 2. FIG. 21 shows an embodiment in which the grooves 21Cb are formed in a spiral shape on the inner surface 21Ca of the inner wall member, and the spiral grooves 21Cb extend from the upper portion of the processing chamber 2 to the lower portion of the inner surface 21Ca along the rotation direction of the stirring device A. This allows the grinding medium to be guided downward in the processing chamber 2.

22 to 27 show modifications of the baffle 5. FIG.
The baffle 5A in Fig. 22 has a flat surface on the side of the buffer chamber 3, and because the inner surface 3a of the buffer chamber 3 is cylindrical from top to bottom, there is a risk that the grinding media that flow into the buffer chamber 3 will remain inside the buffer chamber 3. However, if the slurry passage 12A is used as a gap separator, the grinding media can be prevented from flowing into the buffer chamber 3. It is also possible to install a screen (not shown) at the outlet of the slurry passage 12A on the buffer chamber 3 side to prevent the grinding media from flowing out. The rest of the configuration is the same as that of the wet bead mill 1 in Fig. 2.
The baffle 5B in Fig. 23 is an embodiment in which the slurry passage 12B is used as a gap separator. The other configurations are the same as those of the wet bead mill 1 in Fig. 2.
24 has a slurry inlet opening O1 on its slurry guide surface, a branch passage BR having a slurry outlet opening O2 in its slurry passage 12C, and a second slurry guide surface is formed in the branch passage BR, which is inclined in the opposite direction to the flow direction of the slurry flowing out of the treatment chamber 2 through the slurry passage 12. The other configurations are the same as those of the wet bead mill 1 in FIG.
25 is characterized in that the slurry guide surface extends linearly toward the slurry passage 12D in the cross section of the baffle 5D in the same figure. The other configurations are the same as those of the wet bead mill 1 in FIG.
The baffle 5E in Fig. 26 is characterized in that another grinding disk EX is provided in the middle of the slurry passage 12E, and a slurry guide surface 5Eb is also provided in the processing chamber 2E that houses the grinding disk EX. In this embodiment, both the slurry guide surface 5Ea of the processing chamber 2 and the slurry guide surface 5Eb of the processing chamber 2E extend linearly toward the slurry passage 12E. The other configurations are the same as those of the wet bead mill 1 in Fig. 2.
27 is characterized in that a slurry inflow space SP is formed above the slurry guide surface 5Fa of the treatment chamber 2E, and a slurry guide surface 5Fb extending linearly toward the slurry passage 12E is also provided in the slurry inflow space SP. The other configurations are the same as those of the wet bead mill 1 of FIG.

28 and 29 are diagrams showing modified forms of the agitator A of the wet bead mill 1. The fin disk 26A of the agitator Aa shown in these figures is similar to the fin disk 26 in Fig. 6, but is characterized in that the end disk 27A has a smaller diameter than the fin disk 26A, and further, the agitator fins 27Ac of the end disk 27A are formed only on the side of the fin disk 26A. This makes it possible to effectively prevent the grinding medium from being lifted up to the upper part of the processing chamber 2. The other configurations are the same as those of the wet bead mill 1 in Fig. 2.

Claims (18)

A wet bead mill having a processing chamber that contains a mixture of a slurry containing materials to be crushed and grinding media, a stirring device that rotates in the processing chamber to stir the mixture and disperse and/or crush and/or grind the materials, and a slurry passage that has an opening in the processing chamber and leads the slurry to the outside of the processing chamber, the wet bead mill being characterized in that a baffle is provided in the processing chamber so that a part of the slurry stirred by the stirring device generates a flow toward the inside of the processing chamber, and the baffle mixes the flow of the slurry flowing out of the processing chamber through the slurry passage with the flow of the slurry flowing toward the inside of the processing chamber, thereby preventing the grinding media from flowing out of the processing chamber through the slurry passage. The wet bead mill according to claim 1, characterized in that the baffle has a slurry guide surface surrounding the opening of the slurry passage, and the slurry guide surface is inclined in the opposite direction to the flow direction of the slurry flowing out of the processing chamber through the slurry passage near the opening. The wet bead mill according to claim 2, characterized in that the slurry guide surface is configured as a concave curved surface. The wet bead mill according to claim 2, characterized in that the slurry guide surface is formed of a conical surface inclined toward the inside of the processing chamber toward the opening. The wet bead mill according to claim 2, characterized in that the baffle has a branch passage having an inlet opening for the slurry on the slurry guide surface and an outlet opening for the slurry in the middle of the slurry passage, a second slurry guide surface is formed in the branch passage, and the second slurry guide surface is inclined in the opposite direction to the flow direction of the slurry flowing out of the processing chamber through the slurry passage near the outlet opening. In the wet bead mill according to any one of claims 1 to 5, the agitator has a fin disk facing the slurry guide surface and an end disk facing the bottom surface of the processing chamber, the fin disk has agitating fins extending in a radial direction and protruding toward the slurry guide surface, and the end disk has agitating fins extending in a radial direction and a plurality of through holes extending in an axial direction. The wet bead mill. The wet bead mill according to claim 6, characterized in that the end disk has a smaller diameter than the fin disk. The wet bead mill according to claim 7, characterized in that the stirring fins of the end disk are formed only on the fin disk side. A wet bead mill having a processing chamber that contains a mixture of a slurry containing materials to be crushed and grinding media, an agitation device that rotates in the processing chamber to agitate the mixture and disperse and/or crush and/or grind the materials to be crushed, and a slurry passage that has an opening in the processing chamber and discharges the slurry to the outside of the processing chamber, the wet bead mill being characterized in that a buffer chamber is provided in the processing chamber, the processing chamber and the buffer chamber are connected via the slurry passage, the slurry passage has a slurry inlet in the processing chamber and a slurry outlet in the buffer chamber, and a grinding media separation device that separates the grinding media from the slurry is disposed in the buffer chamber. The wet bead mill according to claim 9, characterized in that the buffer chamber is disposed above the processing chamber, the inner surface of the buffer chamber is formed with a cylindrical surface and a truncated cone-shaped surface extending in a mortar shape from the lower end of the cylindrical surface toward the slurry outlet of the slurry passage, the grinding medium separation device is constituted by a centrifugal separator, the centrifugal separator is disposed at a position surrounded by the cylindrical surface of the buffer chamber, and the outer diameter of the upper part of the centrifugal separator is made larger than the outer diameter of the lower part of the centrifugal separator. The wet bead mill according to claim 10, characterized in that the centrifugal separator is provided with a swastika-shaped slurry passage. The wet bead mill according to claim 9, characterized in that the grinding medium separation device is composed of a gap separator and/or a screen that does not allow the grinding medium to pass through. A wet bead mill having a processing chamber that contains a mixture of a slurry containing materials to be crushed and a grinding medium, a stirring device that rotates in the processing chamber to stir the mixture and disperse and/or crush and/or grind the materials to be crushed, and a slurry passage that has an opening in the processing chamber and leads the slurry to the outside of the processing chamber, characterized in that the inner surface of the processing chamber is formed of a cylindrical surface, and a plurality of grooves extending at a predetermined angle to the axial direction of the rotating shaft of the stirring device are formed at predetermined intervals on the cylindrical surface. The wet bead mill according to claim 13, characterized in that each of the plurality of grooves has a cross-sectional shape that is smoothly curved in a concave shape. The wet bead mill according to claim 13 or 14, characterized in that the plurality of grooves are each formed as parallel grooves extending parallel to the axis of the rotating shaft of the stirring device. The wet bead mill according to claim 15, characterized in that the parallel grooves are divided into upper parallel grooves and lower parallel grooves, and the upper parallel grooves and the lower parallel grooves are arranged out of phase with each other. The wet bead mill according to claim 13 or 14, characterized in that the plurality of grooves are each formed of an inclined groove extending at an angle with respect to the axial direction of the rotating shaft of the stirring device, and the inclined groove is located at a position where the phase of the lower part of the inclined groove is advanced in the rotation direction of the stirring device compared to the phase of the upper part of the inclined groove. 15. The wet bead mill according to claim 13 or 14, characterized in that the groove is formed by a spiral groove that winds around the rotation axis of the stirring device, and the spiral groove extends along the inner surface of the processing chamber from top to bottom along the rotation direction of the stirring device.