Powder classifying device

• US 8,100,269 B2
• Filed: 07/30/2008
• Issued: 01/24/2012
• Est. Priority Date: 07/31/2007
• Status: Active Grant

• Current Assignee: Nisshin Seifun Group Incorporated
• Original Assignee: Nisshin Seifun Group Incorporated
• Inventors: Taketomi, Kenji, Kozawa, Kazumi, Kyugo, Masaru
• Primary Examiner(s): Karmis, Stefanos
• Assistant Examiner(s): Butler, Michael E
• Application Number:
  US12/182,552
• Publication Number:
  US 20090032443A1
• Time in Patent Office: 1,273 Days
• Field of Search: 209/138, 209/139.1, 209/142, 209/143, 209/722, 209/149, 209/150
• US Class Current: 209/722
• CPC Class Codes: B07B 11/04 Control arrangements
• CPC Class Codes: B07B 4/02 while the mixtures fall
• CPC Class Codes: B07B 7/086 generated by the winding course of the gas stream

Abstract

The powder classifying device classifies powder having a particle size distribution and collects the classified powder. The device includes a disc-like cavity to which the powder is supplied and where the supplied powder is classified, a powder supply port for supplying the powder to the cavity, guide vanes arranged so as to extend from an outer periphery of the cavity in an inner direction at a predetermined angle, a discharge unit for air streams including fine particles discharged from the cavity, a collection unit for coarse particles discharged from the cavity and air nozzles arranged below the guide vanes on an outer peripheral wall of the cavity along a tangential direction of the outer peripheral wall and blow compressed air into an inside of the cavity.

Claims

1. A powder classifying device which classifies powder having a particle size distribution and having been supplied and collects the classified powder, said powder classifying device comprising:

a first disc-like cavity to which the powder having the particle size distribution is supplied which disc-like cavity serves as a powder material dispersing zone and which is an open free space formed by arranging a first upper disc-like member and a first lower disc-like member in a face-to-face relationship while keeping a predetermined space therebetween, and forms a first material classifying zone for classifying the powder having no moving parts;

a powder supply port for supplying the powder having the particle size distribution to the first disc-like cavity;

a plurality of first air nozzles that are arranged on a first outer peripheral wall of the first disc-like cavity along a tangential direction of the first outer peripheral wall and blow compressed air into an inside of the first disc-like cavity for powder material dispersion so as to form a first circulating stream by action of the compressed air in the inside of the first disc-like cavity to the powder supplied to the inside of the first disc-like cavity;

a plurality of first guide vanes provided below the plurality of first air nozzles so as to extend from an outer periphery of the first disc-like cavity in an inner direction at a predetermined angle, and for sucking outside air through spaces between the plurality of first guide vanes to promote a centrifugal action of the powder supplied together with the first circulating stream into the first disc-like cavity;

a first discharge unit for air streams including fine particles, having sizes equal to or smaller than a first classification point, discharged from the first disc-like cavity;

a second disc-like cavity that is an open free space formed by arranging a second upper disc-like member and a second lower disc-like member in a face-to-face relationship while keeping a predetermined spaced therebetween, and forms a second material classifying zone that has no moving parts therein, receives the air streams from the first disc-like cavity including a part of the powder which has such a particle size distribution and is the remainder of the powder that is not discharged through the first discharge unit, and classifies the part of the powder included in the received air stream and having such the particle size distribution;

a plurality of second air nozzles that are arranged on a second outer peripheral wall of the second disc-like cavity along a tangential direction of the second outer peripheral wall and blow compressed air into an inside of the second disc-like cavity for powder material dispersion so as to form a second circulating stream by action of the compressed air in the inside of the second disc-like cavity to the remainder of the powder supplied to the insider of the second disc-like cavity;

a plurality of second guide vanes arranged so as to extend from an outer periphery of the second disc-like cavity at a predetermined angle, and for sucking outside air through spaces between the plurality of second guide vanes to promote a centrifugal action of the remainder of the powder supplied together with the second circulating stream into the second disc-like cavity;

a second discharge unit, for air streams containing medium particles, having sizes equal to or smaller than a second classification point, discharged from the second disc-like cavity;

a coarse particle collection unit for collecting coarse particles having a particle size more than the particle size of the medium particles that are not discharged from the second discharge unit and that are discharged from the second disc-like cavity;

a plurality of third air nozzles that are arranged below the plurality of second guide vanes, on the second outer peripheral wall of a lower side of the second disc-like cavity along the tangential direction of the second outer peripheral wall, and blow compressed air into the inside of the second disc-like cavity for powder material dispersion to return medium particles not discharged to the second discharge unit and present among coarse particles having sizes exceeding the second classification point at a coarse particle collection unit side of the second disc-like cavity, to the second material classifying zone of the second disc-like cavity; and

a suction blower connected to the first discharge unit,

wherein the first discharge unit comprises a fine particle collection unit for collecting the fine particles.

2. The powder classifying device according to claim 1, wherein the second discharge unit is provided in a central portion of the second disc-like cavity, and comprises a medium particle collection unit that collects the medium particles having sizes equal to or smaller than the second classification point set in a lower centrifugal chamber having the second disc-like cavity as a main component.

3. The powder classifying device according to claim 1, further comprising a ring-like edge provided in a central portion of at least one of an upper surface and a lower surface in the first disc-like cavity.

4. The powder classifying device according to claim 1, wherein the first discharge unit is provided in and coupled to a central portion of the first disc-like cavity.

5. The powder classifying device according to claim 1, wherein the plurality of third air nozzles blow the compressed air into a space between the plurality of second guide vanes and the second lower disc-like member at the coarse particle collection unit side of the second disc-like cavity to return the medium particles present in the space between the plurality of second guide vanes and the second lower disc-like member to the second material classifying zone of the second disc-like cavity.

6. The powder classifying device according to claim 1, wherein the plurality of third air nozzles blow the compressed air into a material re-classifying zone formed on the coarse particle collection unit side of the second disc-like cavity and between an outer periphery of the second lower disc-like member positioned at the coarse particle collection unit side and the outer peripheral wall of the lower side of the second disc-like cavity to return the medium particles in the material re-classifying zone.

7. A powder classifying device which classifies powder having a particle size distribution and having been supplied and collects the classified powder, said powder classifying device comprising:

a first annular cavity to which the powder having the particle size distribution is supplied;

a powder supply port for supplying the powder having the particle size distribution to the first annular cavity;

a plurality of first air nozzles that are arranged on a first outer peripheral wall of the first annular cavity along a tangential direction of the first outer peripheral wall and blow compressed air into an inside of the first annular cavity for powder material dispersion so as to form a first circulating stream by action of the compressed air in the inside of the first annular cavity, and to disperse preliminarily the supplied powder;

a disc-like cavity which is located below the plurality of first air nozzles and where the powder having the particle size distribution and having been supplied together with the first circulating stream is classified, which disc-like cavity serves as a powder material dispersing zone and is an open free space formed by arranging an upper disc-like member and a lower disc-like member in a face-to-face relationship while keeping a predetermined space therebetween, the disc-like cavity forming a material classifying zone for classifying the powder, the material classifying zone having no moving parts therein;

a plurality of guide vanes arranged so as to extend from an outer periphery of the disc-like cavity in an inner direction at a predetermined angle, and for sucking outside air through spaces between the plurality of guide vanes to promote a centrifugal action of the powder supplied together with the first circulating stream into the disc-like cavity;

a discharge unit for air streams including fine particles, having sizes equal to or smaller than a classification point, discharged from the disc-like cavity;

a coarse particle collection unit for collecting coarse particles having a particle size more than the particle size of the fine particles that are discharged from the disc-like cavity and that are not discharged through the discharge unit;

a plurality of second air nozzles that are arranged below the plurality of guide vanes on a second outer peripheral wall of a lower side of the disc-like cavity along a tangential direction of the second outer peripheral wall and blow compressed air into an inside of the disc-like cavity to return fine particles not discharged to the discharge unit and present among coarse particles having sizes exceeding the classification point at a coarse particle collection unit side of the disc-like cavity, to the material classifying zone of the disc-like cavity; and

a suction blower connected to the discharge unit,

wherein the discharge unit comprises a fine particle collection unit for collecting the fine particles, and

wherein outside air is sucked by the suction blower into the disc-like cavity through spaces between the plurality of guide vanes and discharged from the disc-like cavity through the discharge unit so that a second circulating stream for classifying the powder is formed in the material classifying zone of the disc-like cavity.

8. The powder classifying device according to claim 7, wherein the plurality of first air nozzles are arranged in the first annular cavity to form a dispersing zone for the supplied powder having the particle size distribution in the first annular cavity.

9. The powder classifying device according to claim 7, further comprising a second annular cavity arranged below the disc-like cavity,

wherein the plurality of second air nozzles are arranged in the second annular cavity to form in the disc-like cavity a classifying zone for the powder having been dispersed.

10. The powder classifying device according to claim 7, wherein the plurality of first air nozzles are arranged in the first annular cavity, and the plurality of second air nozzles are arranged in the second annular cavity to disperse and classify the powder having the particle size distribution that was supplied into the disc-like cavity located between the first annular cavity and the second annular cavity.

11. The powder classifying device according to claim 7, wherein a direction in which the air streams are guided is integrally adjustable with the plurality of guide vanes.

12. The powder classifying device according to claim 7, further comprising a ring-like edge in a central portion of at least one of an upper surface and a lower surface in the disc-like cavity.

13. The powder classifying device according to claim 7, wherein the discharge unit is provided in and coupled to a central portion of the disc-like cavity.

14. The powder classifying device according to claim 7, wherein the plurality of second air nozzles blow the compressed air into a space between the plurality of guide vanes and the lower disc-like member at the coarse particle collection unit side of the disc-like cavity to return the fine particles present in the space between the plurality of guide vanes and the lower disc-like member to the material classifying zone of the disc-like cavity.

15. The powder classifying device according to claim 7, wherein the plurality of second air nozzles blow the compressed air into a material re-classifying zone formed on the coarse particle collection unit side of the disc-like cavity and between an outer periphery of the lower disc-like member positioned at the coarse particle collection unit side and the outer peripheral wall of the lower side of the disc-like cavity to return the fine particles in the material re-classifying zone.