JP5283472B2 - Jet mill - Google Patents

Description

  The present invention relates to a fluidized bed jet mill that produces various fine particles such as toner, chemicals and foods by pulverization.

A jet mill is a device that uses a high-pressure gas jetted from a nozzle as an ultra-high-speed jet, pulverizes particles into this high-speed flow, and pulverizes them to extremely fine particles by impact between the particles. Since particles that have not collided with each other remain as coarse particles, it is generally treated in combination with a classifier. The injected gas reaches around the speed of sound. Jet mills have a relatively low temperature rise due to pulverization, so they are suitable for pulverization of substances with low melting points and substances that must be avoided because they change quality, and are used in the manufacture of food, pharmaceuticals, printing toners, etc. .

Jet mills include fluidized bed type and swirl type.
A swirling jet mill has a plurality of jet nozzles that are inclined in the swirling direction on the outer periphery of a disk-shaped casing, and the raw material is pulverized by being caught in a high-speed flow ejected from the nozzle, and particles in the swirling flow It is crushed when they collide with each other. The pulverized particles are classified in the radial direction using a swirling flow, and particles having a predetermined particle size or less collected at the center of the swirling flow are discharged from the mill. The remaining particles are crushed again in a swirling flow to form fine particles. Since the swirl type jet mill does not have a complicated driving part and has a simple device structure, it can be easily disassembled and cleaned. However, since the swirling particles scrape the inner wall of the apparatus, there is a problem of apparatus wear and contamination in which impurities are mixed into product particles. Since a rotating rotor is not used for the classification part, it is easy to use materials that are vulnerable to bending and impact, such as ceramics, and ductile materials such as resin. It is easy to take measures.

A fluidized bed type jet mill has a pulverizing section having an opposing jet nozzle at the lower part of the mill and a classification part at the upper part of the mill. In most models, classification is performed using a classification rotor. FIG. 29 is a structural diagram illustrating the mechanism of a conventional general fluidized bed jet mill.
In a fluidized bed jet mill, two or more jet nozzles are mounted facing each other so that the airflow collides at a position away from the wall, so the raw materials collide near the intersection and efficiently pulverize. There is little equipment wear and contamination. Further, as a classification mechanism independent of the pulverization unit, for example, a classification rotor that classifies coarse particles and fine particles by a centrifugal force of a rotating flow formed by a rotating blade and a drag force of air flowing in the axial direction is used. The classification rotor can easily adjust the particle size according to the number of rotations of the rotor and the flow rate of the passing air, and a powder product having a sharp particle size distribution can be obtained.

  However, there are problems in that it is difficult to clean or difficult to remove depending on the raw material. Even if the rotor blades can be disassembled, cleaning requires a considerable amount of work. Although devices using ceramics or cemented carbide can be manufactured, there is a possibility of damage because the rotor rotates. Since the classifying rotor has a drive unit equipped with a bearing and is supported by the bearing and rotating, stress is always generated and centrifugal force acts. Therefore, when a ceramic material with low toughness is used, if the ceramic is broken, the fragments are scattered with great energy due to centrifugal force, and if the lining is applied to the inner surface of the casing, the lining may be broken. Therefore, ceramic classifying rotors often use zirconia, which has relatively high toughness but is expensive.

  Furthermore, since it is difficult to clean the drive unit completely, use a labyrinth seal, mechanical seal, or a fluorine-resin contact seal to prevent the powder from entering the drive unit and grease from the drive unit. In addition, shaft sealing using seal gas is performed. In addition, there is a minute gap between the rotating rotor and the non-rotating duct or casing, but this gap is sealed to prevent particulates from passing through the classification rotor and directly entering the discharge duct. It is common to supply gas. These sealing gases become 10% or more of the amount of gas used in the jet mill, and energy efficiency decreases.

Patent Document 1 discloses a technical idea in which an inner cylinder is provided in a pulverization chamber in a fluidized bed jet mill (counter jet mill pulverization classifier) including a pulverization nozzle and a classification rotor that are installed facing each other. . Since the inner cylinder provided in the pulverization chamber prevents turbulence in the fluidized bed and promotes convection, the object to be crushed efficiently moves to the classification unit. For this reason, excessive crushing is reduced and production efficiency is improved.
JP 2004-275935 A

  However, the swirl type jet mill has no moving parts and the structure of the apparatus is simple. However, since the swirling particles scrape the inner wall of the apparatus, apparatus wear and contamination become a problem. On the other hand, the fluidized bed jet mill efficiently crushes the raw material and has little contamination, and the crushing efficiency is greatly improved by providing the inner cylinder, but it has a moving part such as a classification rotor, so the mechanism is complicated. Become. In addition, the seal air supplied to the seal to prevent the powder from short-passing through the gap between the shaft seal of the drive unit and the rotating classification rotor and the stationary duct is necessary, and the consumption of compressed air increases, resulting in poor energy efficiency. In addition, problems such as deterioration of the particle size distribution and occurrence of burn-in occur due to poor gap adjustment.

  Therefore, the object of the present invention is to maintain the pulverization performance and the small amount of contamination of the conventional fluidized bed type jet mill, while having ease of cleaning like a swirl type jet mill, ceramic, cemented carbide, The purpose is to provide a fluidized bed jet mill that uses a classification mechanism that does not have moving parts and that can be made of various materials such as plastics, and that can easily take measures against adhesion and wear resistance.

In order to solve the above problems, a jet mill according to the present invention includes a pulverization / classification casing and an outlet casing, and the pulverization / classification casing has two or more jet nozzles arranged at the lower part of the casing toward the center. A swirl flow generator having a pulverization section, a louver having louver blades arranged around the central axis in a direction in which a flowing air flow forms a swirl flow, and an outer peripheral opening, and a swirl flow generator and a ceiling provided on a ceiling portion of the crush section And an outlet casing is provided with a floor opening corresponding to the opening of the classification part ceiling and a discharge port connected to the suction duct.
When the high-pressure air in the pulverization section flows out of the louver, a swirl flow is formed in the classification section. It is carried out of the mill.

  The jet mill according to the present invention efficiently pulverizes the raw material stored in the pulverization unit by being caught in the jet flow formed by the jet nozzle and colliding with the vicinity of the central axis, and the pulverized product is swirled with the airflow in the ceiling portion. A swirl flow is formed in the classifying section by flowing into the classifying section from the louver of the generator. Large particles contained in the swirling flow are discharged to the outside by centrifugal force, returned to the pulverizing portion from the outer peripheral opening, fall down along the wall, and are engulfed and pulverized again by the high-speed air flow of the jet nozzle. On the other hand, the sufficiently small particles gather at the center of the swirling flow, are drawn by the suction duct, and are carried out of the jet mill.

  The jet mill according to the present invention retains the function of efficiently pulverizing the material by entraining the jet material in the collision of the jet flow by concentrating the jet flow formed by the jet nozzle on the axial center portion of the pulverization unit. In addition, by using a swirl flow generator without moving parts, devices with moving parts such as a classification rotor are not used, so there is less wear and less contamination, and the overall structure of the apparatus is simple and completely disassembled. And can be easily cleaned. In addition, since a rotating rotor is not used for the classification part, materials that are vulnerable to bending and impact, such as ceramics, and ductile materials such as resin can be used, making it easy to take measures against adhesion and wear resistance. .

  Furthermore, since seal air that prevents the powder from short-passing through the gap between the shaft seal of the drive unit and the rotating classification rotor and the stationary duct becomes unnecessary, the total air amount is reduced and energy efficiency is improved. Deterioration of the particle size distribution and burn-in due to insufficient seal air amount and gap adjustment failure will not occur. Moreover, since the size of the particles taken out from the jet mill is determined by the balance between the centrifugal force caused by the swirling flow and the centripetal force caused by the exhaust flow in the classification part, adjustment is easy. Moreover, it can change also with the diameter of the ceiling opening of a classification part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partial cross-sectional view conceptually showing the configuration and operation of a jet mill according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA of the swirl flow generator of the present embodiment, and FIG. It is a block diagram of the jet mill of embodiment.

  As shown in FIGS. 1 to 3, the jet mill 100 according to the present embodiment includes a crushing / classifying casing 10 and an outlet casing 80. The pulverization / classification casing 10 includes a pulverization unit 20 in which two or more jet nozzles 22 are arranged toward the center of the lower part of the casing 10, and a center axis in a direction in which a flowing airflow forms a swirling flow. The louver 44 having the louver blades 42 arranged side by side and the classification part 30 having the outer peripheral opening 32 and the swirling flow generator 40 provided in the ceiling part of the crushing part 20 and the opening 84 provided in the ceiling are formed. The Under the swirl flow generator 40, a draft tube 24 reaching the floor plate 16 of the crushing / classifying casing 10 is provided. A hole 26 through which the jet flow from the jet nozzle 22 passes is provided at the lower portion of the draft tube 24. The outlet casing 80 is provided with a floor opening 84 corresponding to the opening 84 in the classification section ceiling and a discharge port 82 connected to a suction duct (not shown). A raw material supply nozzle 12 for supplying raw material particles is provided on a side surface of the pulverization / classification casing 10.

  When high-pressure gas is supplied to a plurality of jet nozzles 22 facing each other, the raw material particles in the pulverization / classification casing 10 are entrained in the gas ejected from the jet nozzle 22 at a high speed, and the raw material particles are brought into contact with each other at the intersection of the jet or the jet. It is crushed by colliding. As the high-pressure gas, various gases suitable for the object such as air, nitrogen gas, argon gas, other gas, or water vapor that easily becomes high pressure can be used. For normal use purposes in the present embodiment, air having a pressure of about 0.4 to 0.8 MPa is supplied. The pulverized particles ascend with the airflow in the central portion of the pulverization / classification casing 10 and the draft tube 24 and reach the inside of the swirl flow generator 40. As shown in FIG. 2, the louver 44 of the swirling flow generator 40 includes louver blades 42 arranged around a central opening 34 connected to the draft tube 24, and high-pressure gas containing particles entering from the central opening 34 is louvered. When it flows out through the gap between the blades 42, a swirl flow is formed around the swirl flow generator 40. This swirling flow flows into the classifying unit 30 and causes a swirling flow in the same direction in the classifying unit 30.

  An opening smaller than the outer diameter of the louver, that is, a floor opening 84 of the outlet casing, is provided on the central axis of the swirling flow generator 40 in the partition wall 86 that partitions the pulverization / diversion casing 10 and the outlet casing 80, and the airflow is not illustrated. It is pulled by an external blower, passes through the floor opening 84, and is discharged from the discharge port 82 of the outlet casing 80 to the suction duct. The swirling flow formed in the classification unit 30 generates a centrifugal force accompanying rotation, and generates a high-speed flow sucked by the discharge port 82 at the center portion. Due to the balance between the centripetal force associated with the discharge flow toward the floor opening 84 and the centrifugal force due to the swirl flow, the fine particles gathered in the central portion of the swirl flow pass through the discharge opening 82 from the floor opening 84 through the discharge port 82. And are carried out of the jet mill 100. The coarse particles descend from the outer peripheral opening 32 through the vicinity of the side wall surface of the pulverizing / dividing casing 10 to the vicinity of the jet nozzle 22 of the pulverizing unit 20 and are again entangled in the jet and pulverized.

The draft tube 24 of the present embodiment extends to the floor plate 16 at the bottom of the pulverizing / dividing casing 10, and the jet flow from the jet nozzle 22 passes through a hole 26 provided in the lower side wall surface of the draft tube and is contained in the draft tube 24. It collides near the central axis. The pressurized air supplied to the jet nozzle 22 flows from the draft tube 24 to the swirling flow generator 40, so that a stable air flow can be reliably formed and a strong swirling flow can be generated in the classifying unit 30. Is possible.
Therefore, it is suitable for generating fine particles and particles having a sharp particle size distribution.

In addition, the diameter of the hole 26 provided in the lower side wall surface of the draft tube needs to be a size that does not prevent the jet from entering and does not flow backward. Usually, it is preferably about 0.5 to 1.5 times the distance from the tip of the jet nozzle 22 to the surface of the draft tube 24. The shape of the hole 26 is not limited to a circle but may be a square or an ellipse.
FIG. 4 is a cross-sectional view showing a modified example of the draft tube 24 extending to the floor plate 16 of the crushing / dividing casing 10. For example, a pipe 28 having a constriction as shown in FIG. 4 is attached to the draft tube 24 at a position where the jet nozzle 22 receives the jet, and particles are entrained in the jet by the ejector effect generated by the jet nozzle 22 and the pipe 28. It is possible to increase the pulverization efficiency.

5 to 7 are views showing another embodiment relating to the swirling flow generator.
The jet mill shown in FIG. 5 has the simplest configuration in which the swirl flow generator 40 is not provided with a draft tube. The swirling flow generator 40 is suspended from the top plate 88 of the outlet casing 80 by the shaft 62, and the size and strength of the swirling flow in the classifying unit 30 are adjusted by adjusting the distance between the swirling flow generator 40 and the partition wall 86. In addition, the classification granularity can be easily controlled by changing the swirling flow velocity and the centripetal force related to the centrifugal force. However, since there is no draft tube, the air supplied from the jet nozzle 22 does not pass through the swirl flow generator 40 in its entirety, and a considerable amount flows around the swirl flow generator 40 and flows into the classification unit 30. The flow velocity of the swirling flow decreases and the turbulence increases. Accordingly, a product having a rough particle size distribution with a rough particle size is obtained.

  The jet mill shown in FIG. 6 is configured such that the height of the swirling flow generator 40 can be adjusted by the same shaft 62 as in FIG. 5, but the swirling flow generator 40 is provided with a draft tube 24. The jet mill of FIG. 6 is a type in which the draft tube 24 has only a point above the intersection of the jets from the jet nozzle 22. A part of the air ejected from the jet nozzle 22 leaks from the draft tube 24 and circulates from the outside of the swirling flow generator 40, so that the efficiency is not so good.

  The jet mill shown in FIG. 7 is configured such that the height of the swirling flow generator 40 can be adjusted by the same shaft 62 as in FIG. 5, and the draft tube 24 installed in the swirling flow generator 40 is the same as that shown in FIG. Similarly, there is only a point above the intersection of the jets from the jet nozzle 22, but since the skirt portion 25 is at the lower end and spreads downward, most of the air jetted from the jet nozzle 22 flows into the draft tube 24, Since the swirl flow is formed in the classification section by the swirl flow generator 40, the product particle size becomes finer and the particle size distribution becomes sharper. Although the product quality does not reach the jet mill having the configuration shown in FIG. 3, the apparatus can be manufactured more easily.

FIG. 8 shows a jet mill in which a mechanism for adjusting the distance between the swirling flow generator 40 and the top plate 88 is added to the structure shown in FIG. The draft tube 24 is fixed to the floor plate 16, and the swirl flow generator 40 is suspended from the top plate 88 by a shaft 62. Since the suspension length of the shaft 62 can be adjusted, the height of the swirl flow generator 40 and, consequently, the height of the classifying unit 30 can be adjusted. The draft tube 24 has its tip inserted into a skirt pipe 53 extending on the bottom plate portion of the swirling flow generator 40, and the position of the swirling flow generator 40 is shifted even if the height of the swirling flow generator 40 changes. And no air leakage occurs.
The jet mill shown in FIG. 8, like the jet mill shown in FIG. 3, introduces almost the entire amount of air to efficiently generate a swirling flow, and also changes the height of the swirling flow generator to The set value of the classification particle size can be changed by adjusting the height.

FIG. 9 is a plan sectional view of the outlet casing 80. The discharge port 82 is attached in a direction in contact with the cylindrical portion of the casing. A swirling flow that rotates in the same direction in the outlet casing 80 is generated by the swirling flow generated in the classification unit 30. Therefore, the discharge port 82 extends in the flow direction of the swirling flow. With the arrangement shown in FIG. 9, the swirl flow in the outlet casing 80 can be strengthened in combination with the suction effect of the blower, and thus the swirl flow in the classification unit 30 can be made stronger. In FIG. 9, the casing of the outlet casing 80 is cylindrical, but in the case of a large machine, it is often a spiral chamber shape. Also in this case, it is preferable to extend the discharge port 82 in the tangential direction.
FIG. 10 shows a structure in which the exhaust duct 96 is directly attached to the floor opening 84 of the partition wall 86. With this structure, the degree of freedom in design is small, but it is easy to manufacture, and is easy to disassemble and easy to clean.

Next, a method for adjusting the product granularity will be described.
In the jet mill of this embodiment, the particle size of the product particles largely depends on the sieving accuracy in the classification unit 30. Therefore, the product particle size can be adjusted by adjusting the classification particle size in the classification unit 30. The basic method of adjusting the product particle size is to adjust the flow velocity of the swirling flow in the classifying unit 30, and to adjust the height of the classifying unit 30 by adjusting the height of the swirling flow generator 40 described above and the outlet. In addition to the method of changing the diameter of the floor opening 84 of the casing 80, there is a method of adjusting the speed of the airflow ejected from the swirling flow generator 40.

FIG. 11 is a drawing for explaining a method for adjusting the gap between the louver blades 42, and FIG. 12 is a drawing for explaining a modification thereof.
The amount of gas in the jet mill is determined by the amount of blowout from the jet nozzle, and is substantially determined by the relationship between the gas pressure to be supplied and the nozzle diameter. Although there is a method of adjusting the pressure of the supply gas, it is not usually adopted. FIG. 11 is a view for explaining a mechanism for adjusting the gas amount by placing the fulcrum 74 at the axial center side end point of the louver blade 42 and simultaneously rotating the louver blade 42. FIG. 11A shows the louver blades 42 rotated in the direction to lie down to narrow the gap between the louver blades. FIG. 11B shows the louver blades 42 rotated in the direction to stand to increase the gap. Show. When the amount of gas supplied from the central opening 34 does not change, if the gap between the louver blades 42 is reduced as shown in FIG. 11A, the blowing speed from the gap is increased and is outside the swirl flow generator 40. The flow velocity of the swirling flow increases. On the other hand, when the gap is increased as shown in FIG. 11B, the blowing speed is reduced and the swirling flow velocity is lowered, so that the particle size can be adjusted by the opening degree of the louver.

FIG. 12 shows the louver blade 42 with a fulcrum 74 placed at an intermediate position instead of the axial center end point. Every other louver blade is a fixed wing 52. By rotating the movable louver wing 42, the gap between the fixed wing and the movable wing is adjusted, and the outflow speed is adjusted to change the swirling flow velocity. Adjust the classification particle size. FIG. 12A shows the case where the louver blade is closed, and FIG. 12B shows the case where the louver blade is opened.
Even if the pivot point 74 is placed at an end point on the side close to the outer periphery of the louver blade 42, the gap between the louver blades can be adjusted by the rotation. The clearance can be adjusted by sliding the louver blade 42 in and out. Furthermore, there is a method in which the louver blade is formed of a thin plate of metal or resin and the opening is adjusted by elastically deforming a part thereof.

  The shape of the louver blade 42 is not limited to a thin plate, and may be a flat plate or a member having a three-dimensional curved surface as long as the airflow can be ejected in the circumferential direction. It is required to have a shape with as little resistance as possible and easy airflow. FIG. 13 is a drawing showing another example of the louver blade 42 that can adjust the flow velocity and has a shape in which airflow easily flows. The louver blade 42 is thick on the axial center side and has a thin shape in the outer circumferential direction, and is rotatably supported by a rotating shaft 78 provided in the vicinity of the end point on the axial center side. Even if a large rotation angle is taken, the change in the gap is small, and precise gap adjustment is possible.

  FIG. 14 is a drawing showing another method for adjusting the classification particle size. Since the bottom plate 46 of the swirl flow generator 40 is provided with a slit through which the louver blade 42 can pass and the swirl flow generator 40 is moved up and down, the height of the gap between the louver blades 42 is adjusted at the level of the bottom plate 46. It is possible to adjust the swirling flow velocity by changing the gas blowing speed. A box 66 is provided on the lower side of the bottom plate 46 so as not to suck gas from the slits of the bottom plate 46.

FIGS. 15-21 is a figure which shows the modification of the classification part 30 containing the swirl | vortex flow generator 40. FIG.
The classification part 30 shown in FIG. 15 is provided with a bank 92 around the floor opening 84 on the classification part 30 side of the partition wall 86. Since the swirling flow velocity decreases near the surface of the partition wall 86, coarse particles may flow along the surface of the partition wall 86 and enter the outlet casing 80 from the floor opening 84 and may be mixed into the product. The bank 92 has a function of preventing such movement of coarse particles and preventing quality deterioration due to dripping.

FIG. 16 shows a structure in which a cylindrical portion 94 is further provided inside the floor opening 84. The presence of the cylindrical portion 94 improves the possibility of preventing unintended particles from entering the outlet casing 80, affects the particle size distribution of the product, and changes the adhesion or wear state. Can be expected.
FIG. 17 shows a configuration in which the top plate of the swirling flow generator 40 is a truncated cone 54 instead of a flat plate. When the truncated cone 54 is used, since the cross-sectional area of the flow path decreases toward the center, the swirl flow rate increases and the centrifugal force increases, so that there is an effect of lowering the classification point.
Further, FIG. 18 shows that a disc-like convex portion 56 is further formed in the vicinity of the apex of the truncated cone 54 of the top plate of the swirling flow generator 40. Providing the convex portion 56 further on the top of the truncated cone 54 has an effect of preventing the movement of coarse particles into the central portion and making it difficult to mix into the product.

19 to 21 show the swirl flow generator 40 having a cone 58 formed on the lower side of the top plate. By forming the lower surface of the top plate in a conical shape, airflow and particles can be evenly distributed to the louver blades 42 arranged in an annular shape and smoothly guided. In addition, when a highly adherent raw material is handled, there is an effect of making it difficult to adhere to the inside of the swirling flow generator 40 by smoothing the flow.
19 shows a flat plate on the upper side of the top plate, FIG. 20 shows a case where a truncated cone 54 is formed on the upper side of the top plate, and FIG. 21 shows a case where a convex portion 56 is formed on the central portion of the truncated cone 54 on the upper side of the top plate. It represents.

The bottom plate 46 of the swirling flow generator 40 has a larger diameter than the top plate 48. This is to prevent the gas from the lower side of the swirling flow generator 40 from being involved in the swirling flow and reducing the swirling speed as much as possible. FIG. 22 shows a barrier plate in which the gas from the lower side of the swirling flow generator 40 is not mixed with the swirling flow of the classification section 30 by being bent toward the classification section 30 at the periphery of the bottom plate 46 of the swirling flow generator 40. It is drawing which shows what 60 is provided.
The particle size of the jet mill can be adjusted by changing the diameter of the opening 84 provided on the ceiling of the classifying unit 30. In this case, the peripheral parts of the opening 84 can be replaced and adapted. It is possible to use a method of exchanging a set of parts having an opening diameter. Also, the hole diameter may be adjusted using a mechanism similar to the lens diaphragm.

FIG. 23 is a view showing a modified example of the crushing / classifying casing 10. The jet mill shown in the figure is an example applied to a typical one having the configuration shown in FIG. The flow velocity of the swirling flow in the classifying unit 30 increases as the difference between the outer diameter of the louver 44 of the swirling flow generator 40 and the hole diameter of the floor opening 84 of the outlet casing increases, so the classifying unit 30 has a certain size. is necessary. On the other hand, if the volume of the pulverization unit 20 is too large, the powder density decreases, the concentration of particles caught in the jet flow of the jet nozzle 22 decreases, the collision opportunity decreases, and the pulverization efficiency decreases. For this reason, the large pulverization / classification casing 10 can maintain the pulverization efficiency by providing the tapered portion 14 whose diameter decreases downward in the middle part and reducing the diameter in the pulverization portion 20.

It goes without saying that the above-mentioned types of jet mills can also improve the grinding efficiency by forming the tapered portion 14 and reducing the diameter of the grinding portion 20.
FIG. 24 is a view showing a mode in which the tapered portion 14 is provided in the middle part of the crushing / classifying casing 10 provided with the swirling flow generator 40 suspended from above, and FIG. 25 shows the swirling flow generator 40 suspended from above. It is drawing which shows the aspect which provided the taper part 14 in the middle part of the grinding | pulverization / classification casing 10 provided with the draft tube 24 which has the skirt part 25 extended below.

  26 and 27 show a jet mill of the type in which a swirling flow generator is supported by a shaft from the bottom of the casing. 26 corresponds to the apparatus of FIG. 8, and FIG. 27 corresponds to the apparatus of FIG. The support height of the swirling flow generator 40 can be adjusted by the feeding length of the shaft 64, and the classification point of the particles taken out to the outlet casing 80 can be easily adjusted. In the method in which the swirl generator 40 is supported by the shaft from above, small particles that easily adhere to the shaft gather and adhere near the shaft. However, in the apparatus shown in the figure, there is an air current near the shaft 64 and it is difficult to adhere and easy cleaning. It is. In addition, since the jet flow from the jet nozzle 22 collides with the shaft 64, the powders collide with each other in the air and are pulverized, so that there is no mixing of wear powders, and it is possible to process even highly adhering raw materials. Although the advantages of the jet mill are lost, it has been confirmed that the pulverization efficiency is higher when the jet hits the impact.

  FIG. 28 is a diagram showing an apparatus that positively utilizes the effect of having a surface with which a jet from the jet nozzle 22 collides. If the conical part 72 is formed in the lower end part of the shaft 64 of FIG. 26 and a jet collides with a conical surface, grinding | pulverization efficiency can be improved further compared with colliding with the cylindrical shaft 64. FIG. The height of the swirl flow generator 40 is adjusted by the screwing depth of the screw plug 68.

  The material composing the jet mill according to the present invention has a wider range of materials that can be used than those using a rotating rotor. For example, materials such as swirling flow generators, draft tubes or shafts are only required to be able to withstand the stress caused by airflow or crushing pressure. In addition to metals, hard urethane, various engineering plastics, cemented carbides, ceramics, etc. The wear-resistant material can be used without any problem. Moreover, various coatings by plating, thermal spraying, PVD method, DLC, etc. can be applied to the surface, and the coating film is hardly peeled off. Moreover, since it is comprised with a stationary member and the precision like a rotary rotor is not requested | required, surface treatment in which deformation | transformation by process heat is anxious about carburization, nitriding, etc. can be utilized. In this way, treatments suitable for improving wear resistance and preventing adhesion can be widely selected.

The fluidized bed jet mill equipped with the swirl flow generator according to the present invention is much smaller than the rotary rotor type and has no centrifugal force because only the stress due to the airflow acts on the swirl flow generator. Even if it breaks and debris scatters, there is no worry of breaking other parts. In addition, since materials and the like can be widely selected, it can be manufactured at low cost using inexpensive and high hardness alumina. Since there is no drive part and the swirl flow generator can be easily disassembled, it is easy to clean, and since seal gas is not used, energy efficiency is high.
In addition, although the gas to be used is mainly air, gas, such as nitrogen, argon, or helium, can also be utilized. Further, it is possible to increase the temperature of the gas to be supplied and dry it during pulverization.

  The fluidized bed jet mill of the present invention can be applied to various materials, including food and pharmaceutical raw materials, carbon-based materials such as graphite and coke, resin-based chemical products such as resins and toners, other metals and minerals, and organic and inorganic materials. Can be used.

1 is a partial cross-sectional view conceptually showing the configuration and operation of a jet mill according to an embodiment of the present invention. It is AA sectional drawing of the swirling flow generator of this embodiment. It is a block diagram of the jet mill of this embodiment. It is sectional drawing which shows the modification of the draft tube in this embodiment. It is sectional drawing which shows another embodiment regarding the swirl | vortex flow generator in this embodiment. It is sectional drawing which shows another embodiment regarding the swirl | vortex flow generator in this embodiment. It is sectional drawing which shows another embodiment regarding the swirl | vortex flow generator in this embodiment. It is sectional drawing which shows the embodiment which provided the mechanism which adjusts the distance of a swirling flow generator and a top plate in the jet mill described in FIG. It is a plane sectional view of the outlet casing in this embodiment. It is sectional drawing which shows the structure which attached the exhaust duct directly to the floor opening of a partition in this embodiment. It is drawing explaining the method of adjusting the clearance gap between louver blades in this embodiment. It is drawing explaining the modification of FIG. It is drawing which shows another example of the louver blade in this embodiment. It is drawing which shows the other method of adjusting a classification particle size in this embodiment. It is drawing which shows the modification of the floor opening in the classification part of this embodiment. It is drawing which shows another modification of the floor opening in the classification part of this embodiment. It is drawing which shows the modification of the swirling flow generator top plate outer side in the classification part of this embodiment. It is drawing which shows another modification of the swirl | flow generator top plate outer side in the classification | category part of this embodiment. It is drawing which shows the modification of the swirl | flow generator top board internal rule in the classification part of this embodiment. It is drawing which shows the modification of the top-plate outer side in the turning flow generator of FIG. It is drawing which shows another modification of the top plate outer side in the swirl flow generator of FIG. It is sectional drawing which shows what the barrier plate was provided in the swirl | vortex flow generator in this embodiment. It is sectional drawing which shows the modification of the grinding | pulverization / classification casing in this embodiment. It is sectional drawing which shows what applied the grinding | pulverization / classification casing of FIG. 23 to another aspect. It is sectional drawing which shows what applied the grinding | pulverization / classification casing of FIG. 23 to another aspect. It is sectional drawing which shows the aspect which supported the swirl | vortex flow generator in this embodiment with the shaft from the casing bottom face. It is sectional drawing which shows what applied the swirling flow generator support method of FIG. 26 to another aspect. It is sectional drawing which shows what applied the swirling flow generator support method of FIG. 26 to another aspect. It is sectional drawing which shows the mechanism of the conventional fluidized bed type jet mill.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Crushing / classification casing 12 Raw material supply nozzle 16 Floor plate 20 Crushing part 22 Jet nozzle 24 Draft tube 25 Skirt part 26 Hole through which jet flows 28 Pipe 30 Classification part 32 Outer peripheral opening 34 Center opening 40 Swirling flow generator 42 Louver blade 44 Louver 46 Bottom plate 48 top plate 52 fixed wing 53 skirt pipe 54 truncated cone 56 convex portion 58 cone 60 barrier plate 62 shaft 64 shaft 66 box 68 screw plug 72 conical portion 74 fulcrum 78 rotating shaft 80 outlet casing 82 discharge port 84 provided on the ceiling Opening (floor opening)
86 Bulkhead 88 Top plate 92 Bank 94 Cylindrical part 96 Exhaust duct 100 Jet mill

Claims (17)

A jet mill having a crushing / classifying casing and an outlet casing,
The pulverization / classification casing has a pulverization part in which two or more jet nozzles are arranged toward the center part at the lower part of the casing, and a central axis so that an air current is jetted in a circumferential direction above the pulverization part. A swirling flow generator having a louver having louver blades arranged in a row, an outer peripheral opening communicating with the pulverization part, and a classification part surrounded by a bottom plate of the outlet casing,
The outlet casing includes the bottom plate having a floor opening leading to the classification unit, a cylindrical side wall perpendicular to the bottom plate, and a discharge port.
Jet mill.   2. The jet mill according to claim 1, wherein the swirling flow generator includes a mechanism for adjusting a clearance width of the louver blade, and controls a classification particle size by adjusting a jet velocity.   2. The jet mill according to claim 1, wherein the swirl flow generator includes a mechanism for adjusting a height of a gap between the louver blades, and controls a classification particle size by adjusting a jet velocity.   The jet mill according to any one of claims 1 to 3, further comprising a draft tube perpendicular to the swirl flow generator.   5. The jet mill according to claim 4, wherein the draft tube reaches a bottom surface of the pulverizing / classifying casing, and a hole through which a jet flow from the jet nozzle passes is provided below the wall surface.   The jet mill according to claim 5, wherein a pipe having a throttle that exhibits an ejector effect in cooperation with the jet nozzle is provided in a hole through which the jet flows.   The mechanism for adjusting the height of the swirling flow generator is provided, and the classification particle size is controlled by adjusting the height of the classification unit according to the height of the swirling flow generator. The jet mill as described in any one of Claims.   The jet mill according to any one of claims 1 to 7, wherein an upper surface of the swirl flow generator has a truncated cone shape.   The jet mill according to claim 8, wherein a disc-shaped convex portion is further formed on the top of the truncated cone on the upper surface of the swirl flow generator.   The jet mill according to any one of claims 1 to 9, wherein a central portion of the swirl flow generator on a lower side of the top plate has a conical shape.   The jet mill according to any one of claims 1 to 10, wherein a barrier plate bent toward the classification unit side is provided at an inner edge of the outer peripheral opening. The jet mill according to any one of claims 1 to 11, wherein a shaft that supports the swirl flow generator is supported on a bottom surface of the pulverization / classification casing. The jet mill according to any one of claims 1 to 12, wherein an inner diameter of the pulverization / classification casing is formed narrower than the classification part in the pulverization part.
  The jet mill according to any one of claims 1 to 13, wherein the outlet casing includes a mechanism for adjusting a diameter of the floor opening and controls a classification particle size by the diameter.   The jet mill according to any one of claims 1 to 13, wherein the outlet casing is provided with a bank on a side of the classification portion at a peripheral edge of the floor opening.   The jet mill according to any one of claims 1 to 15, wherein the outlet casing is provided with the discharge port in a tangential direction of a cylinder of the side wall in a downstream direction of a swirling flow generated in the outlet casing.   The jet mill according to any one of claims 1 to 15, wherein the outlet casing is formed by vertically attaching a discharge pipe to the bottom plate.

Images