JP2012179535A - Wet medium agitation mill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably operate by suppressing the temperature rise within a machine while preventing dispersion failure due to the bias of medium beads, beads packing phenomenon, and the separation of the beads and a liquid material.SOLUTION: A wet medium agitation mill 1 has a vessel 11, a rotary shaft 18, and a rotary rotor 34. The rotary rotor 34 is arrange in the bottom part or the vessel 11 and has pegs 47. Pegs 48 are arranged in the inner wall 11a of the vessel facing the pegs 47. A grading blade 31 is arranged above the rotary rotor 34. A crashing chamber 35 and the grading chamber 32 are formed between the rotary rotor 34 and the vessel inner wall 11a and between the grading blade 31 and the vessel inner wall 11a, respectively. A liquid raw material 2 is fed from under the vessel 11 and the liquid raw material 2 is crashed and dispersed in the crashing chamber 35. The liquid raw material 2 and the medium beads 3 are pushed back by the centrifugal force of the grading blade 31 and stayed in the crashing chamber 35 for a long time to be crashed and dispersed.

Description

  The present invention relates to a wet medium stirring mill (also referred to as “bead mill”) used for pulverizing and dispersing liquid raw materials such as various inks from micron to nano-sized fine particles.

  Conventionally, for pulverization and dispersion of liquid materials such as various inks, polymerization toners, paints, pigments, photosensitizers, liquid crystal color filters, electronic materials, carbon nanotubes, various plant cells, metal powders, inorganic substances, organic substances, etc. A wet medium stirring mill using a rotating rotor or the like is used. In a medium agitation mill, various liquid materials can be micronized by planting pegs on the rotating rotor and the vessel (stator) facing it, or by providing irregularities on the surface of the rotor or stator, or by providing an agitation disk. It is pulverized and dispersed into size and nano size particles.

  Such a medium agitating mill supplies medium beads such as zirconia beads to the space where the raw material liquid flows, such as between the rotor and the stator, and applies shear stress and shearing force to the raw material particles to be processed by the medium beads. Grind and disperse. In this case, the medium beads are supplied to the distribution space of the raw material liquid at a volume ratio of 60 to 90%, and the medium beads supplied in the distribution space show a complicated movement with the rotor operation. When the liquid raw material passes between the flowing medium beads, shearing stress or the like is applied to the raw material particles to be processed, and the raw material is pulverized and dispersed.

  In recent years, there has been an increasing demand for pulverizing or dispersing raw materials down to nano size, mainly electronic materials. For this reason, the number of medium beads used in the medium agitating mill is increased to 0.3 mm or less, and in particular, the use of fine medium beads of 0.1 mm or less is increasing. When such fine media beads are used, the contact frequency between the liquid raw material and the media beads is dramatically increased, and it is possible to pulverize and disperse to nano size even with less shearing force and shearing force. It becomes.

  On the other hand, in the case of using fine media beads, the solution of the old problem of the media agitating mill is required more reliably. That is, in the medium agitating mill, the medium beads stay 60 to 90% by volume in the machine and move along with the flow of the liquid raw material, so that (1) insufficient dispersion due to bias of the medium beads, (2 Conventionally, there are three problems, namely, a bead packing phenomenon and (3) separation of beads and liquid raw materials. A medium agitation mill using fine medium beads is required to solve these problems more reliably.

  Here, with respect to the above problems (1) and (2), for example, as in Patent Document 1, by reducing the (L / U) ratio of the inner diameter U and the length L of the vessel, A configuration for preventing a bead packing phenomenon due to bias and a phenomenon of destabilizing dispersibility has been proposed. Here, a method is adopted in which a mechanism for circulating the liquid raw material while preventing the bead packing phenomenon and the like is provided, thereby preventing a short pass of the liquid raw material and ensuring dispersibility.

Next, with respect to the problem (3), as in Patent Document 2, the disks are made to face each other, and the influence of the fluid boundary film generated by the liquid raw material is reduced with one being the rotation side and the other being the fixed side. There have been proposed a configuration employing a micro gap screen or a method of eliminating the screen itself and separating and discharging only the medium beads from the liquid raw material by a centrifugal separation mechanism as in Patent Document 3.

JP 2006-346667 A JP-A-10-05563 JP 2006-247557 A JP 2006-320898 A JP 2008-183518 A

  However, in order to solve the above problems (1) and (2), in order to circulate the liquid raw material inside the vessel reliably, as in Patent Documents 4 and 5, the structure of the vessel and the mechanism of the rotating rotor are required. There was a problem of increasing complexity. Further, in the apparatus in which the liquid raw material is circulated in the apparatus, the medium beads themselves are circulated by the circulation of the raw materials, and the number of times of contact between the vessel surface and the medium beads and the rotating rotor surface and the medium beads is increased. For this reason, the relative speed between the vessel surface and the medium beads also increases, and there is a problem that contamination due to wear of the medium beads, which is a defect of the medium stirring mill, may occur.

  On the other hand, regarding the problem of (3), in the apparatus using the counter disk, assuming a 0.1 mm medium bead, the gap (gap) of the micro gap screen by the rotating disk and the fixed disk is set from 30 microns to 50 microns. There is a need to. For this reason, a very high level is required for the working accuracy and assembly accuracy of the disk and each part of the apparatus, and there is a problem that the apparatus cost increases. In addition, in order to secure the passage of liquid raw material and prevent pressure increase in the machine, the passage cross-sectional area of the gap screen may be increased and the screen may be provided in multiple stages, but in this case, the work accuracy and assembly accuracy are higher. A level is required.

  Further, in an apparatus provided with a centrifugal separation mechanism, a system in which medium beads having a large specific gravity are blown by a centrifugal force by a rotating blade and the liquid raw material flows and is discharged against the centrifugal force. However, when this method is employed, fine media beads of 0.1 mm or less cannot be reliably separated 100%, and a small amount of beads are often mixed into the product. In particular, when the viscosity is slightly increased, the centrifugal separation function is lowered and medium beads are mixed in the discharged raw material. The final product after pulverization / dispersion is not allowed to be mixed with one medium bead. However, if there is a possibility that the medium bead is mixed into the discharged material in this way, the discharged product is again discharged from the discharged product. A step of separating the media beads is required. For this reason, in addition to the medium agitating mill, there has been a problem that further equipment for reliably separating the medium beads is required.

  The object of the present invention is to solve the above three problems (1) to (3), to suppress the temperature rise in the machine and to enable stable operation, and to cope with fine beads of 0.1 mm or less. It is to provide a wet medium stirring mill.

  The wet medium agitating mill of the present invention is formed in a bottomed cylindrical shape and contains a bead and a liquid raw material inside, a rotating shaft extending into the vessel from above the vessel and extending in the vertical direction, A wet medium stirring mill attached to the rotating shaft and disposed in the vessel, wherein the vessel communicates with the inside of the vessel at a lower end thereof, and the liquid raw material is supplied. The rotary rotor is disposed above the raw material supply port at the bottom of the vessel, and has a plurality of pegs projecting in the radial direction on the outer periphery thereof, on the inner wall of the vessel Is provided with a plurality of pegs arranged opposite to the pegs of the rotating rotor and projecting in the radial direction, and the rotating rotor is disposed above the rotating rotor in the vessel. The classification blade has a plurality of blades extending in the vertical direction and an annular space formed inside the blade, and the pegs are arranged between the rotary rotor and the inner wall. The medium beads and the liquid raw material are mixed to form a pulverization chamber in which the liquid raw material is pulverized and / or dispersed, and the rotation blade is rotated between the classification blade and the inner wall of the vessel. The medium beads are separated from the liquid raw material by a centrifugal force to form a classification chamber into which the medium beads flow.

  In the present invention, the liquid raw material is supplied from below the vessel of the wet medium agitating mill, and the medium beads and the liquid raw material are mixed in the crushing chamber disposed below the vessel to pulverize and disperse the liquid raw material. The liquid raw material and medium beads in the pulverization chamber stay in the pulverization chamber and are pulverized and dispersed while being pushed back by the centrifugal force of the classification blade. The liquid raw material and medium beads rising from the crushing chamber are separated into liquid raw material and medium beads by the classification blade, and the medium beads are introduced into the classification chamber.

  In the stirring medium mill, the pegs attached to the outer periphery of the rotary rotor and the pegs attached to the vessel are alternately shifted in the axial direction so as not to interfere with each other, and the circumference of the peg tip on the rotary rotor side is arranged. The trajectory may be within an inner circumference of the peg tip on the vessel side. In this case, the overlap width between the circumferential locus of the peg tip on the rotating rotor side and the inner circumference of the peg tip on the vessel side is 2.5 to 6.0% with respect to the inner diameter of the vessel. A range may be set.

  An upper space that communicates with the annular space is formed above the classification blade, and an internal space that directly communicates with the annular space by a screen through which the liquid raw material can not pass but the liquid material passes through the upper space. And may be isolated in an external space communicating with the raw material discharge port. In this case, an upper head having a cylindrical portion protruding upward is placed on the upper portion of the vessel, the screen formed in a cylindrical shape is disposed in the cylindrical portion, and the inside of the cylindrical portion and the internal space are The liquid raw material is circulated from the internal space located inside the cylindrical portion toward the external space located on the outer peripheral side of the cylindrical portion, and the wet medium stirring is performed from the raw material discharge port. You may make it discharge outside a mill. Moreover, you may penetrate the said rotating shaft to an up-down direction in the said cylindrical part in an airtight state. Furthermore, a refrigerant passage through which the refrigerant flows is provided in the rotating shaft, a refrigerant chamber communicating with the refrigerant passage is provided in the rotating rotor, and the refrigerant is supplied to the refrigerant chamber via the refrigerant passage. May be. In particular, it is easy to provide a coolant passage in the rotating shaft by allowing the rotating shaft to penetrate vertically through the cylindrical portion of the upper head in an airtight state.

  On the other hand, the ratio (d / U) of the inner diameter U of the vessel and the outer diameter d of the rotary rotor in the grinding chamber may be set to 0.4 ≦ (d / U) ≦ 0.6. The relationship between the outer diameter G of the classification blade, the outer diameter d of the rotary rotor, and the rotational diameter D of the peg tip of the rotary rotor may be set to D> G> d. Furthermore, the relationship between the axial height H of the classifying blades and the axial length L of the rotary rotor may be set to 1.0L ≧ H ≧ 0.9L. According to the experiments by the inventors, when H / L is set to 0.9 to 1.0, the discharge amount and power consumption of the liquid raw material can be stably maintained, but when H / L is set to 0.7. The flow rate becomes unstable, the bead packing phenomenon tends to occur, and the power consumption becomes unstable.

  The liquid raw material is supplied from below the vessel of the wet medium agitating mill, the crushing chamber using pegs is arranged below the vessel, and the classification chamber using classification blades is arranged above it, so the liquid raw material and medium beads are classified It becomes possible to stay in the crushing chamber while pushing back by the centrifugal force. For this reason, the medium beads do not move excessively in the vessel, and the residence time of the liquid raw material in the vessel becomes long. Therefore, the wear of the medium beads can be suppressed while improving the effect of pulverizing and dispersing the liquid raw material.

  In addition, by providing a classification blade in the classification chamber and a screen above it, the beads can be separated from the liquid raw material in two stages of the classification chamber and the screen while reducing the bead separation load on the screen. It is possible to reliably separate the medium beads while suppressing the phenomenon. Furthermore, by providing a refrigerant passage in the rotating shaft to cool the rotating rotor, it is possible to suppress an increase in temperature in the machine, and it is possible to easily process a raw material sensitive to temperature conditions.

It is explanatory drawing which shows the cross-sectional structure of the medium stirring mill which is one Embodiment of this invention. It is a schematic explanatory drawing which shows one use form of the medium stirring mill of this invention. It is sectional drawing along the AA line of the medium stirring mill shown in FIG. It is sectional drawing along the BB line of the medium stirring mill shown in FIG. It is sectional drawing along CC line of the medium stirring mill shown in FIG. It is a graph which shows the comparison test result with the case where the inside of a rotation rotor is cooled in the test machine of classification blade height H = 90 (H / L = 0.9), and the case where it does not carry out. It is a graph which shows the test result which investigated the influence of the classification blade outer diameter G in the test machine of electric motor capacity | capacitance 5.5kw. It is explanatory drawing which shows the modification of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing an overall configuration of a medium agitating mill 1 (hereinafter, abbreviated as “mill 1” as appropriate) according to an embodiment of the present invention, and shows a cross-sectional configuration of the mill. FIG. 2 is a schematic explanatory view showing a usage pattern of the mill 1 according to the present invention. The medium agitation mill 1 is a so-called wet agitation mill. In the mill 1, the liquid raw material 2 and the medium beads 3 are mixed, and the mixture of both in a slurry state is agitated. The liquid raw material 2 in the mill 1 is pulverized and dispersed into micron-order and nano-order fine particles by shear stress and shearing force generated by the medium beads 3.

  As shown in FIG. 2, the liquid raw material 2 is stored in the raw material liquid tank 4, and is constantly stirred by the stirrer 5 while staying in the tank 4. The liquid raw material 2 in the raw material liquid tank 4 is discharged from the lower part of the tank 4 under the suction action of the metering pump 6, and is supplied to the medium stirring mill 1 through the supply pipe 7. On the other hand, the liquid raw material 2 pulverized and dispersed in the medium agitating mill 1 is returned from the medium agitating mill 1 to the raw material liquid tank 4 via the return pipe 8. The liquid raw material 2 is repeatedly circulated between the raw material liquid tank 4 and the medium agitating mill 1 and is subjected to pulverizing and dispersing actions many times in the medium agitating mill 1 to become a desired product.

  The medium agitating mill 1 includes a vessel 11 to which a liquid raw material 2 is supplied and pulverized and dispersed by medium beads 3. The vessel 11 has a cylindrical shape with a bottom having a truncated cone shape, and the medium beads 3 are accommodated therein. In the center of the bottom of the vessel 11, a raw material supply port 12 for the liquid raw material 2 is provided and connected to the supply pipe 7. A flange 13 is attached to the upper end side of the vessel 11, and a disk-shaped upper head 14 is attached on the flange 13. At the center of the upper head 14, a cylindrical portion 15 is formed so as to protrude upward. A mechanical seal 16 is attached to the upper end of the cylindrical portion 15.

  A shaft hole 17 is opened at the center of the cylindrical portion 15 and the mechanical seal 16, and a rotating shaft 18 is attached to the shaft hole 17. The rotating shaft 18 is rotatably supported by the bearing cylinder 20 by a bearing 19. The bearing cylinder 20 is appropriately held by a bracket 21. The rotating shaft 18 is hollow, and a shaft hole 22 is formed through the central portion along the longitudinal direction (vertical direction in the figure). A cooling water pipe 23 is inserted into the shaft hole 22 as a refrigerant passage. The upper end of the rotating shaft 18 is connected to an external fixed pipe via a rotary joint (not shown), and a coolant 24 such as cooling water is supplied to the cooling water pipe 23. A gap is formed between the shaft hole 22 and the cooling water pipe 23 and serves as a return flow path 25 for the refrigerant 24. That is, the inside of the rotating shaft 18 has a double pipe structure, and the refrigerant 24 supplied by the cooling water pipe 23 is discharged from the return flow path 25.

  The side wall of the vessel 11 also has a double structure for cooling the vessel. A cylindrical jacket 26 is attached to the outside of the vessel 11, and a coolant channel 27 through which a coolant such as cooling water flows is formed inside the jacket 26. The jacket 26 is provided with a refrigerant supply port 28 for supplying the refrigerant to the refrigerant channel 27 and a refrigerant outlet 29 for discharging the refrigerant from the refrigerant channel 27. The refrigerant supply port 28 and the refrigerant discharge port 29 are connected to a refrigerant supply system (not shown). By appropriately supplying cooling water or the like from the refrigerant supply system to the refrigerant flow path 27, the vessel 11 is controlled to a desired temperature condition.

  A classification blade 31 is attached to the lower part of the rotating shaft 18. As shown in FIG. 1, a classification chamber 32 is formed outside the classification blade 31 between the inner wall 11 a of the vessel 11. The classification blade 31 is a sirocco fan-like multi-blade fan, and has a configuration in which a plurality of blades 33 are erected on a circular bottom plate as shown in FIGS. A cylindrical rotary rotor 34 is further attached to the lower end of the rotary shaft 18. As shown in FIG. 1, a crushing chamber 35 is formed outside the rotating rotor 34 between the inner wall 11 a of the vessel 11. That is, in the mill 1, the classification chamber 32 is formed in the upper portion of the vessel 11, and the crushing chamber 35 is formed in the lower portion.

  A cylindrical distance collar 41 is attached between the central boss portion of the classification blade 31 and the lower end portion of the mechanical seal 16. The distance collar 41 is arranged so as to be extrapolated to the rotary shaft 18. The lower end portion of the rotating shaft 18 is hollow, and a shaft hole 42 is formed. The cooling water pipe 23 extends from above in the shaft hole 42, and communication holes 44 and 45 are provided at the lower end and the upper end, respectively. The coolant 24 flows from the cooling water pipe 23 into the shaft hole 42. The refrigerant 24 flows into and fills the refrigerant chamber 46 in the rotary rotor 34 from the communication hole 44 and cools the rotary rotor 34. The refrigerant 24 in the refrigerant chamber 46 enters the shaft hole 42 from the communication hole 45 and is discharged out of the apparatus through the return flow path 25.

  A plurality of pegs 47 are embedded in the outer peripheral portion of the rotary rotor 34 and protrude in the radial direction. On the other hand, a plurality of pegs 48 project from the inner wall 11a of the vessel 11 facing the rotating rotor 34 in the radial direction. As shown in FIG. 3, the pegs 47 on the rotating rotor 34 side and the pegs 48 on the vessel 11 side are alternately arranged in the axial direction so as not to interfere with each other. The rotational diameter (peg 47 tip diameter) D of the peg 47 tip is slightly smaller than the tip inner diameter P of the peg 48, and the circumferential trajectory of the peg 47 is disposed within the inner circumference of the peg 48 tip. Has been. That is, both pegs 47 and 48 are in a state where their tip portions slightly overlap in the axial direction. In the mill 1, the polymerization width is set to about 2.5 to 6.0% with respect to the inner diameter U (about 180 mm) of the vessel 11.

  If the pegs 47 and 48 on the rotating rotor 34 side and the vessel 11 side do not overlap, the crushing and dispersing action by the pegs is insufficient. On the other hand, if the polymerization width of both is too large, the liquid raw material 2 and the medium beads 3 may be excessively contacted to cause contamination due to wear of the medium beads. Therefore, the inventors of the present invention have grasped that the balance between the crushing / dispersing action by the peg and the bead wear suppression is the best when the polymerization width is set within the above range as a result of trial and error. Also set the dimensions in the above range.

  The ratio (d / U) between the rotor outer diameter d of the rotary rotor 34 and the inner diameter U of the vessel 11 is in the range of 0.4 to 0.5. Further, the tip diameter D of the peg 47 and the outer diameter d of the rotor are configured such that the relationship of D ≧ G >> d is established with respect to the outer diameter G of the classification blade 31. In addition, the height L of the rotary rotor 34 is constructed such that H = L or H ≧ 0.9 × L with respect to the height H of the classification blade 31.

  On the other hand, as shown in FIG. 1, a relatively wide annular space 49 is formed between the inside of the classification blade 31 and the rotary shaft 18. An upper space 51 is formed inside the cylindrical portion 15 of the upper head 14, and the annular space 49 communicates with the upper space 51. A cylindrical screen 52 is attached inside the cylindrical portion 15, and the upper space 51 is separated into an internal space 51 a and an external space 51 b by the screen 52. A material discharge port 53 is formed in the cylindrical portion 15 along the radial direction, and the material discharge port 53 communicates with the external space 51b.

  As the screen 52, a screen in which a wire having a triangular cross-section generally called a wedge wire is wound in a cylindrical shape is employed. It is also possible to employ a screen with a thin plate thickness and a high aperture ratio (70 to 80%) using a porous foam metal plate or a sintered metal plate. By adopting such a screen, the pressure loss at the screen portion can be kept low, the liquid raw material can be passed through without any trouble, and fine media beads of 100 microns or less can be separated at the screen portion. Become.

  Next, pulverization and dispersion processing by the mill 1 according to the present invention will be described. Examples of the liquid raw material 2 to be processed by the mill 1 include various inks, polymerization toners, and paints as described above. For the medium beads 3, a ceramic such as zirconia, or a spherical grinding medium such as glass or metal is used. Here, first, the liquid raw material 2 is supplied from the raw material liquid tank 4 to the medium stirring mill 1 via the supply pipe 7. The liquid raw material 2 is supplied into the vessel 11 from the raw material supply port 12. The medium beads 3 are stored in the vessel 11, and the liquid raw material 2 is mixed with the medium beads 3 in the vessel 11.

  In the vessel 11, the liquid raw material 2 is first introduced into the crushing chamber 35, and rises from the lower central portion of the crushing chamber 35 while being uniformly dispersed on the outer periphery of the rotary rotor 34. Here, in the crushing chamber 35, the media beads 3 rotate around the rotary rotor 34 along with the movements of the pegs 47 and 48, and are randomly rotated by the action of the pegs, and the movement is excessively restricted. It stays in the space between the vessel 11 and the rotating rotor 34 without any problem. That is, in the mill 1, the vessel 11 has no circulation path, and the medium beads 3 move together with the rotating rotor 34 and exhibit pulverization and dispersion actions. Therefore, the medium beads 3 stay in the grinding chamber 35 without moving up and down in the axial direction and stay in the grinding / dispersing process. Therefore, an excessive contact opportunity between the medium beads 3 and the rotating rotor 34, the vessel 11, and the pegs 47 and 48 is eliminated, and excessive wear of the medium beads 3 is suppressed.

  As described above, when the liquid raw material 2 is introduced from the raw material supply port 12 in a state where the medium beads 3 stay in the grinding chamber 35, the liquid raw material 2 is uniformly dispersed in the cylindrical space between the rotating rotor 34 and the vessel 11. To rise. At that time, the liquid raw material 2 passes between the medium beads 3, and at the same time, the shearing force and shear stress are uniformly applied. Thereby, the liquid raw material 2 is uniformly dispersed in a short time, and pulverization proceeds. At that time, in the mill 1, the flow space of the medium beads 3 in the pulverization chamber 35 is large, but the medium beads 3 do not move excessively, so that the kinetic energy of the medium beads 3 is efficiently transmitted to the liquid raw material 2. For this reason, it becomes possible to suppress the occurrence of a so-called bead packing phenomenon in which a large amount of medium beads 3 themselves are in a semi-solid state quasi-integrated and an excessive torque is applied to the rotating rotor 34.

  The liquid raw material 2 pulverized and dispersed in the pulverization chamber 35 rises in the vessel 11 and tends to flow into the classification chamber 32. However, in the classification chamber 32, the liquid raw material 2 and the medium beads 3 are pushed back toward the pulverization chamber 35 due to the centrifugal force effect by the rotating action of the classification blade 31, and further pulverization / dispersion processing is performed in the pulverization chamber 35. Then, after a sufficient stay time has elapsed in the crushing chamber 35, the liquid raw material 2 passes through the classification blade 31 and is introduced into the annular space 49. Thus, in the mill 1 of the present invention, the time during which the liquid raw material 2 stays in the cylindrical pulverization space between the rotating rotor 34 and the vessel 11 can be increased by the centrifugal force action generated by the classification blade 31. Become.

  Of the liquid raw material 2 and the medium beads 3 introduced into the annular space 49, the medium beads 3 are pushed out toward the classification chamber 32 by the centrifugal force action of the classification blade 31. On the other hand, the liquid raw material 2 rises from the annular space 49 along the rotation shaft 18 and reaches the screen 52 attached to the inside of the upper head 14 in a cylindrical shape. In this case, in the mill 1, a screen 52 is provided at a sufficient distance from the annular space 49 inside the blade in order to sufficiently apply the centrifugal force of the classification blade 31. Thereby, the medium beads 3 are effectively separated by the classification blades 31, and the medium beads 3 are unlikely to approach the surface of the screen 52. That is, if the screen exists in the vicinity of the inside of the classification blade, the flow velocity increases due to the resistance of the screen, and the centrifugal force of the classification blade is affected. Therefore, in the mill 1, the screen 52 is arranged at a distance from the classification blade 31. ing. As a result, many medium beads 3 are pushed out to the classification chamber 32 side and returned to the grinding chamber 35 side by the centrifugal force action of the classification blade 31. However, when the viscosity of the liquid raw material 2 is relatively high, the medium beads 3 may flow from the annular space 49 into the internal space 51a with the viscous raw material. However, even in such a case, the medium beads 3 are completely separated by the screen 52 and are not mixed into the liquid raw material 2 and discharged outside the apparatus.

  The liquid raw material 2 that has reached the screen 52 completely separates the medium beads 3 and flows into the external space 51 b outside the screen 52. As described above, in the mill 1, after the medium beads 3 are separated by the classification blade 31, the liquid raw material 2 and the medium beads 3 are further completely separated by the screen 52. At that time, the liquid raw material 2 in a state where many medium beads 3 are separated by the classification blade 31 flows into the screen 52. For this reason, the separation load of the medium beads 3 on the screen 52 is reduced, and it is possible to suppress the occurrence of the bead packing phenomenon due to the accumulation of the medium beads 3 in the screen portion. Further, since the medium beads 3 are separated by the two-stage structure of the classification blade 31 and the screen 52, for example, fine beads of 0.1 mm or less can be reliably separated while suppressing bead packing, and the versatility of the apparatus is improved. Figured.

  The liquid raw material 2 that has been sufficiently pulverized and dispersed in the vessel 11 and from which the medium beads 3 have been completely separated is discharged from the external space 51b through the raw material discharge port 53 to the outside of the apparatus. The liquid raw material 2 discharged from the raw material discharge port 53 is returned to the raw material liquid tank 4 via the return pipe 8. The liquid raw material 2 returned to the raw material liquid tank 4 is supplied again to the medium agitating mill 1 through the supply pipe 7, and repeatedly pulverized and dispersed to produce a product having a desired particle size.

  As described above, the mill 1 does not have a moving circulation path in the crushing chamber 35 and is configured to retain the liquid raw material 2 in the crushing chamber 35 for a long time by the centrifugal force action of the classification blade 31. And the liquid raw material 2 will be in the state which has received the grinding | pulverization dispersion | distribution action almost always. Accordingly, the probability that the unground material is discharged from the material discharge port 53 is decreased, the number of circulation of the liquid material 2 is decreased, and the desired pulverized or dispersed material can be obtained in a shorter time. On the other hand, in a conventional circulating medium stirring mill, a large amount of liquid raw material is charged into the mill, and a circulation mechanism is provided inside the machine in order to obtain a desired particle size or degree of dispersion, and the liquid raw material is placed in the grinding chamber portion. Since the system for discharging after passing a plurality of times is adopted, the structure of the apparatus becomes complicated and the processing time becomes longer, which is disadvantageous in terms of cost as compared with the mill 1.

  On the other hand, in the mill 1 according to the present invention, the pulverization / dispersion processing as described above is performed in a state where the vessel 11 and the rotary rotor 34 are cooled. That is, the vessel 11 has a double structure using the jacket 26, and the vessel 11 is cooled by appropriately circulating the refrigerant through the refrigerant flow path 27 in the jacket 26. In addition, the rotary rotor 34 has a double pipe structure as the rotary shaft 18, and the coolant 24 is circulated in the rotary rotor 34 by the cooling water pipe 23 and the return flow path 25, so that the rotation of the rotary rotor 34 is a member in the vessel 11. The rotor 34 can also be cooled.

  In a conventional high-circulation type medium agitating mill, the central part of the rotary shaft in the classification chamber is an annular passage, a liquid material is introduced into the passage, and a rotary joint (rotary joint) is provided at the end of the shaft. A method of discharging raw materials is adopted. This is because the conventional mill uses the centrifugal force of the classification blade to classify the medium beads and the liquid material, and separates the liquid material from the medium beads while bringing the medium beads to the outer peripheral side of the classification chamber. This is because the liquid raw material is required to be discharged from the axial center. However, if the liquid raw material is passed through the annular passage at the center of the shaft, a passage for circulating the refrigerant for cooling the rotating rotor cannot be secured, and the cooling capacity is remarkably deteriorated.

  On the other hand, in the mill 1 of the present invention, the rotary shaft 18 has a double tube structure, and a passage through which the refrigerant passes is secured at the shaft center. For this reason, the liquid raw material 2 and the medium beads 3 are separated by the classification blade 31 of the classification chamber 32 and the liquid raw material 2 is guided to the central portion of the classification blade 31, but the rotating rotor 34 can be cooled. . Thereby, even if it is a raw material sensitive to temperature conditions, it can process in an appropriate temperature environment and product quality is ensured favorable. In the mill 1, instead of an annular passage at the center of the shaft, a raw material distribution route from the annular space 49 between the rotary shaft 18 and the classification blade 31 to the upper space 51, the screen 52, and the raw material discharge port 53 is configured. The liquid raw material 2 is discharged smoothly.

  Using the medium stirring mill 1 of the present invention, a test for pulverizing and dispersing a 10% aqueous solution of calcium carbonate by the following method was performed, and the performance was compared.

After the metering pump 6 was started, the medium agitating mill 1 was started, and the discharged liquid was collected after a lapse of a certain time after the liquid raw material flowed out into the circulation system, and the particle size was measured. The particle size was measured by a dynamic light scattering method using Nanotrack UPA-EX manufactured by Nikkiso Co., Ltd. The processing conditions are as follows.
Medium stirring mill Vessel capacity: 3 liters
Vessel inner diameter: U = 173mm
Number of pegs on the vessel side: 4 x 2 steps
Rotating rotor outer diameter: d = 100mm
Number of rotor side pegs: 4 x 3 steps
Rotating rotor height: L = 100
Rotating rotor speed: 1780 rpm
Pumping volume 10 liters / min
Medium bead filling ratio 73%
Zirconia bead diameter 0.3mm

Example 1
An experiment was conducted under the above conditions, changing the height H of the classification blade 31.
When H / L was 1.0 and 0.9, the discharge amount was stable and the power consumption was also stable.
When H / L was 0.7, the effect of pushing the liquid raw material and medium beads back to the crushing chamber side by the classification blade 31 was reduced. In addition, the flow rate became unstable, the bead packing phenomenon easily occurred, and the power consumption became unstable. That is, by setting H and L to 1.0 L ≧ H ≧ 0.9 L, it is possible to suppress the bead packing phenomenon due to the bias of the medium beads 3 in the mill 1.

(Example 2)
Under the above conditions, in a tester having a classification blade height H = 90 (H / L = 0.9), a comparison test was performed between the case where the inside of the rotary rotor 34 was cooled and the case where it was not performed (see FIG. 6). As shown in FIG. 6, when the rotary rotor 34 was cooled, the discharge temperature of the raw material was clearly lower, and the effect of the cooling structure could be confirmed. Therefore, the mill 1 is effective for processing raw materials sensitive to temperature conditions.

(Example 3)
Under the same conditions as in Example 2, the rotational diameter D of the tip of the peg 47 on the rotary rotor 34 side was 140 mm. In a test machine having an electric motor capacity of 5.5 kw, the influence of the classification blade outer diameter G was examined, and the following data was obtained (FIG. 7). As shown in FIG. 7, the average particle size of the liquid raw material after 100 minutes is smaller when G is larger (FIG. 7B), but the power consumption is increased accordingly (FIG. 7A). Therefore, considering the balance between the particle size and the power consumption, it is preferably larger than the rotor outer diameter d of the rotary rotor 34 but smaller than 120 mm (that is, 1.2 d).

It goes without saying that the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the invention.
For example, the various dimensions in the above-described embodiments are examples, and arbitrary dimensions can be adopted as the size of the apparatus and the like without departing from the above-described relationship. Further, in the above-described mill 1, when the medium beads 3 become 0.2 mm or less, the medium beads 3 are not separated from the liquid raw material only by the effect of the centrifugal force of the classification blade 31 and reach the inner surface of the screen 52 at the upper position. May reach. For this reason, like the wet medium stirring mill 61 of FIG. 8, the spiral screw 62 is equipped in the axial center part of the classification blade 31, and the medium beads 3 are moved from the upper space 51 with the screen 52 to the annular space with the classification blade 31. You may convey toward 49. Thereby, even if the medium beads 3 become minute, it is possible to prevent the medium beads 3 from concentrating on the inner peripheral surface of the screen 52.

DESCRIPTION OF SYMBOLS 1 Medium stirring mill 2 Liquid raw material 3 Medium bead 4 Raw material liquid tank 5 Stirrer 6 Metering pump 7 Supply pipe 8 Return pipe 11 Vessel 11a Inner wall 12 Raw material supply port 13 Flange 14 Upper head 15 Cylindrical part 16 Mechanical seal 17 Shaft hole 18 Rotation Shaft 19 Bearing 20 Bearing cylinder 21 Bracket 22 Shaft hole 23 Cooling water pipe 24 Refrigerant 25 Return flow path 26 Jacket 27 Refrigerant flow path 28 Refrigerant supply port 29 Refrigerant discharge port 31 Classification blade 32 Classification chamber 33 Blade 34 Rotating rotor 35 Crushing chamber 41 Distance Collar 42 Shaft hole 43 Shaft end disk 44 Communication hole 45 Communication hole 46 Refrigerant chamber 47 Peg 48 Peg 49 Annular space 51 Upper space 51a Internal space 51b External space 52 Screen 53 Raw material discharge port 61 Wet medium stirring mill 62 Spiral screw D Rotation Rotor side peg tip diameter Bessel side peg tip inner diameter U Bessel inner diameter G classification blade outer diameter d spinning rotor outside diameter

Claims (10)

A vessel formed in a bottomed cylindrical shape and containing medium beads and a liquid raw material inside,
A rotating shaft extending into the vessel from above the vessel and extending in the vertical direction;
A wet-medium agitating mill having a rotating rotor attached to the rotating shaft and disposed in the vessel,
The vessel has a raw material supply port that communicates with the inside of the vessel and is supplied with the liquid raw material at a lower end thereof.
The rotating rotor is disposed above the raw material supply port at the bottom of the vessel, and has a plurality of pegs projecting radially in the outer periphery thereof,
The inner wall of the vessel is provided with a plurality of pegs arranged to face the pegs of the rotating rotor and projecting in a radial direction,
A classification blade rotating with the rotation rotor is disposed above the rotation rotor in the vessel. The classification blade includes a plurality of blades extending in a vertical direction and an annular space formed inside the blade. Have
Between the rotating rotor and the inner wall, the pegs mix the medium beads and the liquid raw material to form a grinding chamber in which the liquid raw material is crushed and / or dispersed,
A wet medium agitating mill characterized in that a classification chamber into which the medium beads are separated from the liquid raw material and flowed in is formed between the classification blade and the inner wall of the vessel by centrifugal force accompanying rotation of the rotary blade. .   2. The stirring medium mill according to claim 1, wherein the pegs attached to the outer periphery of the rotary rotor and the pegs attached to the vessel are alternately arranged in an axial direction so as not to interfere with each other, and the pegs on the rotary rotor side are arranged. A wet-medium agitating mill, wherein a circumferential trajectory of a tip falls within an inner circumference of the peg tip on the vessel side.   The stirring medium mill according to claim 2, wherein a superposition width of a circumferential locus of the peg tip on the rotating rotor side and an inner circumference of the peg tip on the vessel side is 2. A wet medium stirring mill characterized by being in the range of 5 to 6.0%. In the stirring medium mill according to any one of claims 1 to 3,
Above the classification blade, an upper space communicating with the annular space is formed,
The upper space is separated into an internal space that communicates directly with the annular space and an external space that communicates with a material discharge port by a screen through which the liquid raw material passes but the medium beads cannot pass. Wet medium stirring mill. The stirring medium mill according to claim 4,
An upper head having a cylindrical portion projecting upward is placed on the vessel,
The screen formed in a cylindrical shape is disposed in the cylindrical portion, the inside of the cylindrical portion is partitioned into the internal space and the external space,
The liquid raw material is circulated from the internal space located inside the cylindrical portion toward the external space located on the outer peripheral side of the cylindrical portion, and discharged from the raw material discharge port to the outside of the wet medium stirring mill. Wet medium stirring mill characterized by the above.   The stirring medium mill according to claim 5, wherein the cylindrical portion penetrates in the vertical direction with the rotating shaft in an airtight state.   The stirring medium mill according to any one of claims 1 to 6, wherein a refrigerant passage through which a refrigerant flows is provided in the rotating shaft, a refrigerant chamber in communication with the refrigerant passage is provided in the rotating rotor, A wet medium stirring mill, wherein a refrigerant is supplied to a refrigerant chamber through the refrigerant passage.   The stirring medium mill according to any one of claims 1 to 7, wherein a ratio (d / U) between the inner diameter U of the vessel and the outer diameter d of the rotating rotor in the grinding chamber is 0.4 ≦ ( d / U) ≦ 0.6.   The stirring medium mill according to any one of claims 1 to 8, wherein a relationship among an outer diameter G of the classification blade, an outer diameter d of the rotating rotor, and a rotating diameter D of the peg tip of the rotating rotor is as follows. D> G> d, a wet medium stirring mill characterized by the above-mentioned.   The stirring medium mill according to any one of claims 1 to 9, wherein a relationship between an axial height H of the classification blade and an axial length L of the rotary rotor is 1.0L ≧ H ≧ 0. A wet-medium agitating mill characterized by being .9L.

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