Search

CN-118103148-B - Air flow type classifier

CN118103148BCN 118103148 BCN118103148 BCN 118103148BCN-118103148-B

Abstract

The invention provides an air-flow classifier which can maintain classification precision for a long time and has smaller classification points. The air classifier includes a housing having a ceiling wall and an annular wall provided continuously with an outer edge of the ceiling wall, a classifying plate arranged with a surface facing the ceiling wall of the housing, a classifying chamber formed between the ceiling wall of the housing and the surface of the classifying plate, a gas supply unit for supplying gas into the classifying chamber to generate swirling flow, a raw material supply unit for supplying raw material powder to swirling flow generated in the classifying chamber, a fine powder discharge port provided in a central portion of one of the ceiling wall of the housing forming the classifying chamber and the surface of the classifying plate, a coarse powder discharge port provided on either one of the ceiling wall and the surface of the classifying plate facing the ceiling wall and forming an opening along the outer periphery of the classifying chamber, and a groove portion provided on at least one of the ceiling wall and the surface of the classifying plate.

Inventors

  • NAOHARA KENJI
  • Xiao Fengqiao

Assignees

  • 日清制粉集团本社股份有限公司
  • 日清工程株式会社

Dates

Publication Date
20260508
Application Date
20221004
Priority Date
20211014

Claims (18)

  1. 1. An air-flow classifier is characterized by comprising: A housing having a ceiling wall and an annular wall provided continuously with an outer edge of the ceiling wall; a classifying plate configured to face the ceiling wall of the cabinet; a classifying chamber formed between the ceiling wall of the cabinet and a surface of the classifying plate; A gas supply unit configured to supply gas into the classifying chamber to generate swirling flow; a raw material supply unit configured to supply raw material powder to the swirling flow generated in the classifying chamber; A fine powder discharge port provided in a central portion of one of the ceiling wall of the housing constituting the classifying chamber and the surface of the classifying plate; A coarse powder discharge port provided on either one of the ceiling wall and the surface of the classifying plate facing the ceiling wall and forming an opening along the outer periphery of the classifying chamber, and And a groove portion provided on at least one of the ceiling wall and the surface of the classifying plate.
  2. 2. The air classifier of claim 1 wherein, Further comprises at least one of a first cylindrical portion and a second cylindrical portion, The first cylinder part is arranged at the fine powder discharge port; the second cylindrical portion is provided on the surface of the classifying plate of the classifying chamber, and faces the first cylindrical portion with a predetermined gap therebetween.
  3. 3. The air classifier as claimed in claim 2, wherein the diameter of the first cylindrical portion is different from the diameter of the second cylindrical portion.
  4. 4. The air classifier according to claim 1, wherein a slope is formed on at least one of the ceiling wall of the housing and the surface of the classifying plate, and the groove is provided on the slope.
  5. 5. The air-flow classifier according to claim 2, wherein a slope is formed on at least one of a peripheral edge of the first cylindrical portion of the ceiling wall of the housing and a peripheral edge of the second cylindrical portion of the surface of the classifying plate, and the groove portion is provided on the slope.
  6. 6. The air-flow classifier according to any one of claims 1 to 5, wherein the fine powder discharge port is circular, and the groove portion is provided so as to form a concentric circle with respect to the fine powder discharge port.
  7. 7. The air classifier according to any one of claims 1 to 5, wherein the groove portion is provided on the ceiling wall and the surface of the classifying plate.
  8. 8. The air classifier according to claim 7, wherein the fine powder discharge port is circular, the groove portion is provided concentrically with respect to the fine powder discharge port, and the groove portion provided in the ceiling wall is opposed to the groove portion provided in the surface of the classifying plate.
  9. 9. The air classifier according to claim 7, wherein one of the ceiling wall and the surface of the classifying plate having the fine powder discharge port is provided with a groove portion formed in a concentric circle with the fine powder discharge port along a periphery of the fine powder discharge port, and the other of the ceiling wall and the surface of the classifying plate having no fine powder discharge port is provided with a groove portion formed in a concentric circle opposite to the concentric circle groove portion provided in a periphery area of the fine powder discharge port; The groove portion provided in the concentric circle having the fine powder discharge port and the groove portion provided in the concentric circle having no fine powder discharge port are provided at the same position in a direction orthogonal to a direction in which the ceiling wall of the casing of the classifying chamber and the surface of the classifying plate face each other.
  10. 10. The air classifier according to any one of claims 1 to 5, wherein a plurality of the grooves are provided along the periphery of the fine powder discharge port.
  11. 11. An air classifier as claimed in claim 2 wherein the first cylindrical portion is provided in the ceiling wall and the groove portion is provided in the surface of the classifying plate.
  12. 12. An air classifier as claimed in claim 2 wherein the second cylindrical portion is provided on the surface of the classifying plate and the channel portion is provided on the ceiling wall.
  13. 13. The air classifier as claimed in claim 4 or 5, wherein the inclined surface is inclined in such a manner that the height of the classifying chamber gradually rises from the outside of the classifying chamber toward the center.
  14. 14. The air classifier as claimed in claim 4 or 5, wherein the inclined surface is inclined in such a manner as to be inclined from the outside of the classifying chamber toward the center and the height of the classifying chamber is lowered.
  15. 15. The air-flow classifier according to any one of claims 1 to 5, 11, and 12, wherein the raw material supply unit is connected to any one of the ceiling wall and the surface of the classifying plate constituting the housing of the classifying chamber, and supplies the raw material powder to the swirling flow generated in the classifying chamber.
  16. 16. The air-flow classifier according to any one of claims 1 to 5, 11 and 12, wherein the raw material supply unit has a nozzle for discharge for supplying the raw material powder to the swirling flow generated in the classifying chamber.
  17. 17. The air-flow classifier according to any one of claims 1 to 5, 11 and 12, wherein the gas supply portion has a plurality of air nozzles, each of which is arranged along an outer edge of the classifying chamber and at equal intervals from each other in a circumferential direction of the classifying chamber.
  18. 18. The air-flow classifier according to any one of claims 1 to 5, 11 and 12, wherein the gas supply portion has a plurality of guide vanes, each of which is arranged along an outer edge of the classifying chamber and at equal intervals from each other in a circumferential direction of the classifying chamber.

Description

Air flow type classifier Technical Field The present invention relates to an air classifier for classifying raw material powder having a particle size distribution into fine powder and coarse powder at a desired particle size (classification point) by utilizing a balance between centrifugal force and resistance of a swirling flow formed by gas to the powder. And more particularly, to an air classifier capable of maintaining classification accuracy and having smaller classification points. Background In the past, fine particles such as oxide fine particles, nitride fine particles and carbide fine particles have been used in the technical fields of electric insulating materials such as semiconductor substrates, printed circuit boards, various electric insulating parts, high-hardness and high-precision mechanical working materials such as cutting tools, dies, bearings, functional materials such as humidity sensors, sintered bodies for producing precision sintered molding materials, sputtering parts such as materials required to have high-temperature and abrasion resistance for producing engine valves, electrodes of fuel cells, electrolyte materials, various catalysts, and the like. By using such fine particles, the bonding strength and compactability, and even the functionality, of the dissimilar ceramics and the dissimilar metals to each other, and to each other in the production of sintered bodies, sputtering components, and the like, can be improved. The fine particles can be produced by a chemical method in which various gases or the like are chemically reacted at a high temperature, or a physical method in which a substance is decomposed and evaporated by a light beam such as an electron beam or a laser beam to produce fine particles. The fine particles produced by the above production method have a particle size distribution, and the coarse powder and the fine powder are mixed together. In the case of using the fine particles for the above-mentioned applications, a low content ratio of coarse powder is preferable because good properties can be obtained when the content ratio of coarse powder in the fine particles is low. In addition, since the fine metal particles can obtain good properties even when the content ratio of the coarse powder is low, it is preferable that the content ratio of the coarse powder is low. For this reason, for example, an air classifier and a powder classifying device are used in which powder is centrifugally separated into coarse powder and fine powder by swirling flow. For example, patent document 1 describes a powder classifying device that conveys and supplies powder having a particle size distribution by an air flow. The powder classifying device of patent document 1 includes a hollow space (disc-shaped hollow space) in which a space for classifying a powder having a particle size distribution is provided, a powder supply port for supplying the powder having a particle size distribution to the disc-shaped hollow space, a plurality of guide blades arranged so as to extend from the outer periphery of the disc-shaped hollow space in an inner direction at a predetermined angle, a discharge portion including an air flow of fine powder discharged from the disc-shaped hollow space, and a coarse powder recovery portion discharged from the disc-shaped hollow space, and a plurality of air nozzles arranged below the plurality of guide blades and along a tangential direction of the outer peripheral wall of the disc-shaped hollow space, for blowing compressed air into the coarse powder recovery portion side inside the disc-shaped hollow space, and for returning the fine powder located on the coarse powder recovery portion side to the disc-shaped hollow space. Patent document 2 describes a classifying device in which powder supplied from a supply port provided in an upper portion of a device body is guided downward while swirling in the device body, a suction pipe composed of multiple pipes having suction ports at an upper end is provided in a center portion of the device body, and powder having a smaller particle diameter among the powder guided downward while swirling is sucked from the suction port through the suction pipe. In patent document 2, powders having different particle diameters are sucked one by a suction tube composed of multiple tubes, and recovered. Prior art literature Patent literature Patent document 1 Japanese patent application No. 4785802 Patent document 2 Japanese patent laid-open No. 2000-107698 Disclosure of Invention Technical problem to be solved by the invention In the powder classification device of patent document 1, raw material powder having a particle size distribution can be classified into fine powder and coarse powder at a desired particle size (classification point), but recently, the particle size of fine powder required is becoming smaller, and therefore, further miniaturization of the classification point of the powder classification device is desi