Apparatus for volumetric metering of small quantity of powder from fluidized beds
(19) AUSTRALIAN PATENT OFFICE (54) (51)6 (21) (87) (30) (31) (43) (43) (71) (72) Title Apparatus for volumetric metering of small quantity of powder from fluidized beds International Patent Classification(s) B01J 008/00 B01J 008/18 B0 U 008/38 Application No: 2002350351 (22) Application Date: 2002.12.17 WIPO No: WO03/051503 Priority Data (33) Country US 200510277 Number 10/016,129 (32) Date 2001 .12.17 Publication Date : 2003 .06.30 Publication Journal Date : 2003 .08.28 Applicant(s) THE UNIVERSITY OF WESTERN ONTARIO Inventor(s) Zhu, Jesse; Zhang, Hui; Ma, Ying Liang; Wen, Jianzhang -1- The present invention provides a fluidized bed for dispensing small quantities of powders. The fluidized bed is made using a porous housing to permit injection and removal of fluid through the surrounding walls to improve the operation of the bed particularly for small particles of the group C size, including significantly reducing powder adhesion to the walls. In one aspect of the invention the fluidized bed housing is rotated about its longitudinal axis, which may be oriented at any suitable angle. A system for changing the volume of the bed is described as is a system for incorporating injection nozzles within the bed for constant agitation and prevention of powder adhering to the walls of the housing. THEREFORE WHAT IS CLAIMED IS : 1. A fluidized bed for dispensing powders, comprising: a) a housing defining an enclosure for containing particulate matter, said housing including a fluid injection means for injecting a fluid into said enclosure for fluidizing particulate matter contained within said housing for forming a dilute phase alone or a dilute phase and a dense phase of fluidized powder in said housing; and b) volumetric metering means connected to said housing and in flow communication with said enclosure through an outlet passageway for withdrawing pre-selected amounts of said particulate matter from said housing.
2. The fluidized bed according to claim 1 including air flow inducing means for inducing effective air flow patterns in said enclosure for reducing sticking of the particulate matter to the housing walls.
3. The fluidized bed according to claim 1 or 2 wherein said volumetric metering means is detachable from said housing.
4. The fluidized bed according to claim 1,2 or 3 wherein said volumetric metering means includes a particulate collector defining a pre-selected volume.
5. The fluidized bed according to claim 4 wherein said particulate collector includes a support plate having at least one cavity having said pre-selected volume.
6. The fluidized bed according to claim 5 wherein said at least one cavity is a plurality of cavities each having a pre-selected volume.
7. The fluidized bed according to claim 4,5 or 6 wherein said particulate collector can be attached and detached from said outlet passageway. <Desc/Clms Page number 29> 8. The fluidized bed according to claim 6 including a plurality of particulate collectors mounted on a support member, said support member being mounted to said housing with one of said plurality of particulate collectors in said outlet passageway, including a positioning mechanism for positioning each of said particulate collectors mounted on said support member in said outlet passageway.
9. The fluidized bed according to any one of claims 1 to 8 wherein said outlet passageway is a first outlet passageway and said volumetric metering means is a first volumetric metering means, including at least a second outlet passageway and at least a second volumetric metering means connected to said housing and in flow communication with said enclosure through at least second outlet passageway for withdrawing pre-selected amounts of said particulate matter from said housing from said at least second outlet passageway.
10. The fluidized bed according to any one of claims 1 to 9 including timing means for controlling a length of time said particulate matter is withdrawn from said enclosure.
11. The fluidized bed according to claim 10 wherein said timing means includes valve means in said outlet passageway connected to a timer for opening and closing said valve means for controlling a length of time said particulate matter is withdrawn from said enclosure.
12. The fluidized bed according to claim 11 wherein said valve means is a solenoid located in said outlet passageway, and a control means connected to said solenoid for actuating said solenoid for opening and closing said outlet passageway. <Desc/Clms Page number 30> 13. The fluidized bed according to any one of claims 1 to 12 wherein said housing includes a porous wall having a suitable porosity to allow flow of fluid through said wall while preventing most of the particulate matter contained within said housing from passing therethrough, and including a gas distribution manifold adjacent to said porous wall for injecting gas into said housing for fluidizing said particulate matter contained within said enclosure.
14. The fluidized bed according to claim 13 wherein said housing includes additional porous walls having a suitable porosity to allow flow of fluid through the additional walls while preventing most of the particulate matter contained within said housing from passing therethrough.
15. The fluidized bed according to claim 14 wherein said outlet passageway is positioned on said housing so that said particulate matter is withdrawn through said outlet passageway from said dilute phase 16. The fluidized bed according to any one of claims 1 to 12 wherein said housing includes a cylinder having spaced end walls defining a cylindrical housing having a cylindrical axis, wherein said cylinder is porous, said porous cylinder having a suitable porosity to allow flow of fluid through the cylinder wall while preventing most of the particulate matter contained within said housing from passing therethrough.
17. The fluidized bed according to claim 16 including rotation means for rotating said cylindrical housing about said cylindrical axis.
18. The fluidized bed according to claim 17 including a plate slidably mounted within said cylinder and drive means for moving said plate along a longitudinal axis of said cylinder for adjusting a volume of said enclosure. <Desc/Clms Page number 31> 19. The fluidized bed according to claim 16,17 or 18 wherein said outlet passageway is located in an end wall located at one end of said cylinder.
20. The fluidized bed according to claim 17,18 or 19 wherein said cylindrical housing is oriented so that said cylindrical axis is vertical, and wherein said housing rotates about said vertical axis.
21. The fluidized bed according to claim 17,18 or 19 wherein said cylindrical housing is oriented so that said cylindrical axis is horizontal, and wherein said cylindrical housing rotates about said horizontal axis.
22. The fluidized bed according to any one of claims 1 to 21 including agitation means operably coupled to said fluidized bed for agitating said particulate matter inside said housing.
23. The fluidized bed according to claim 22 wherein said agitation means is one of a vibration generator for transmitting vibrational energy to agitate said particulate matter, an ultrasonic wave generator for transmitting ultrasonic waves to agitate said particulate matter, and an acoustic wave generator for transmitting acoustic energy to said particulate matter.
24. The fluidized bed according to claim 22 wherein said agitation means includes a gas agitation means including a pressurized gas supply in communication with said enclosure for removing particulate matter adhering to interior walls of said housing.
25. The fluidized bed according to claim 24 wherein said gas agitation means includes at least one tube having one end connected to said pressurized gas supply and at least one nozzle attached to a free end of said tube located in a pre-selected position within said enclosure. <Desc/Clms Page number 32> 26. The fluidized bed according to any one of claims 1 to 25 including gas purging means in communication with said enclosure for removing particulate matter adhering to said housing.
27. The fluidized bed according to claim 26 wherein said gas purging means includes an elongate tube inserted into said housing, said elongate tube having at least one hole in a wall of the tube disposed along a length of the tube located in said housing.
28. The fluidized bed according to claim 16 wherein said volumetric metering means includes a particulate collector defining a pre-selected volume.
29. The fluidized bed according to claim 28 wherein said particulate collector includes a collector plate having at least one cavity located in a front surface of said collector plate and having said pre-selected volume, said collector plate being positioned within said outlet passageway with said front facing toward said enclosure so particles from said fluidized bed accumulate in said at least one cavity.
30. The fluidized bed according to claim 28 wherein the said particulate collector includes a support plate and a blister plate mounted on a surface of said support plate, said blister plate including at least one cavity of said pre-selected volume.
31. The fluidized bed according to claim 30 wherein said at least one cavity is a plurality of cavities each having a pre-selected volume, said cavities extending right through said blister plate, said support plate including holes through said plate and positioned so that when said blister plate is attached to said support plate the cavities in said blister plate are in registration with holes in said support plate, and including a porous filter sandwiched between said support plate and said blister plate for allowing gas to flow therethrough but not particulate matter. <Desc/Clms Page number 33> 32. The fluidized bed according to claim 31 wherein said particulate collector includes an elongate bar strip to which a plurality of support plates are detachably mountable with a back surface of each support plate mounted on a front surface of said elongate bar strip, a blister plate being mounted on a front surface of each support plate, and wherein said elongate bar strips are perforated at positions where said support plates are mountable.
33. The fluidized bed according to claim 32 including suction means engagable to a back surface of said elongate bar strip for applying suction to said particulate collector.
34. The fluidized bed according to claim 32 including a positioning mechanism for moving said elongate bar strip across said outlet passageway for positioning each of said blister plates mounted on said support plate in said outlet passageway.
35. The fluidized bed according to claim 16 including agitation means operably coupled to said fluidized bed for agitating said particulate matter inside said housing.
36. The fluidized bed according to claim 35 wherein said agitation means is one of a vibration generator for transmitting vibrational energy to agitate said particulate matter, an ultrasonic wave generator for transmitting ultrasonic waves to agitate said particulate matter, and an acoustic wave generator for transmitting acoustic energy to said particulate matter.
37. The fluidized bed according to claim 35 wherein said agitation means includes a gas agitation means including a pressurized gas supply in communication with said enclosure for removing particulate matter adhering to interior walls of said housing. <Desc/Clms Page number 34> 38. The fluidized bed according to claim 37 wherein said gas agitation means includes at least one tube having one end connected to said pressurized gas supply and at least one nozzle attached to a free end of said tube located in a pre-selected position within said enclosure.
39. The fluidized bed according to claim 38 where said at least one tube is a plurality of tubes, each having a nozzle attached at its free end thereof, and wherein some of said tubes are made of rigid material.
40. The fluidized bed according to claim 39 wherein at least one of said plurality of tubes is made of a flexible material so that as gas is flowed through said tube with an effective gas pressure said free end with said nozzle attached thereto moves about within said enclosure.
41. The fluidized bed according to claim 1 wherein said housing is a cylindrical housing including a first cylinder having a first diameter and a second cylinder having a second diameter less than said first diameter with an interior of said second cylinder defining said enclosure containing said powder, said second cylinder being located within, and concentric with, said first cylinder, said second cylinder having a cylinder wall being made of a porous material, said cylindrical housing having a cylindrical axis coextensive with cylindrical axes of said first and second cylinders, said cylindrical housing including first and second end walls attached to opposed ends of said concentric cylinders, including a selected number of spaced elongate walls disposed around said second cylinder and running along the length of both cylinders,STDC0311 said elongate walls extending between an inner surface of said first cylinder and an exterior surface of said second cylinder thereby defining a plurality of chambers equal to the selected number of elongate walls in an annular space between said first and second cylinders. <Desc/Clms Page number 35> 42. The fluidized bed according to claim 41 wherein said fluid injection means for injecting a fluid into said enclosure for fluidizing particulate matter includes a fluid inlet located in said first end wall in communication with an interior of said second cylinder for injecting fluid into an interior of said second cylinder wherein said fluid flows through said porous wall of said second cylinder into said enclosure.
43. The fluidized bed according to claim 42 wherein said one of said first end wall includes a housing having a porous end wall located at the end of said second cylinder, and a nonporous annular end wall extending between, and in sealing engagement with, the end portions of said first cylinder and the second cylinder, and a nonporous wall spaced from said porous end wall defining therebetween an inlet chamber, and a fluid inlet in said nonporous wall spaced from said porous end wall, wherein fluid is injected into said inlet chamber which then passes through said porous end wall into said enclosure.
44. The fluidized bed according to claim 41 including air flow inducing means for inducing air flow patterns in said enclosure for reducing sticking of the particulate matter to interior walls, said air flow inducing means including a selected number of fluid ports located in said first cylinder and disposed about a circumference of said first cylinder with a fluid port associated with each of said chambers, each fluid port including a valve for opening and closing said fluid port, including control means for opening and closing said valves according to a pre-selected schedule.
45. The fluidized bed according to claim 41 wherein said outlet passageway is located in on the first and second end walls.
46. The fluidized bed according to claim 41 including gas purging means in communication with said enclosure for removing particulate matter adhering to said housing. <Desc/Clms Page number 36> 47. The fluidized bed according to claim 46 wherein said gas purging means includes an elongate tube inserted into the second cylinder and extending along its cylindrical axis, said elongate tube having at least one hole in a wall of the elongate tube disposed along a length of the tube located in said second cylinder.
48. The fluidized bed according to claim 41 wherein said first and second cylinders are mounted on a frame for rotation about said cylindrical axis, including drive means coupled to said first and second cylinders for rotating said cylinders, and wherein said end walls mounted on said frame at the ends of said concentric cylinders in sealing engagement therewith, and wherein said fluid injection means for injecting a fluid into said enclosure for fluidizing particulate matter includes a fluid inlet located in one section of one of said end walls and aligned to be in flow communication with at least one of said chambers during rotation of said concentric cylinders wherein fluid in said at least one of said chambers flows through said porous cylindrical wall into the enclosure defined by said second cylinder,STDC0361 including a fluid outlet passageway located in a second section of said end wall and aligned to be in flow communication with at least another chamber during rotation of said concentric cylinders wherein fluid flowing from said enclosure through said porous second cylinder wall into said at least another chamber exits through said fluid outlet passageway.
49. The fluidized bed according to claim 48 including gas purging means in communication with said enclosure for removing particulate matter adhering to said cylindrical housing..
50. The fluidized bed according to claim 49 wherein said gas purging means includes an elongate tube inserted into the second cylinder and extending along its cylindrical axis, said elongate tube having at least one hole in a wall of the tube disposed along a length of the tube located in said second cylinder. <Desc/Clms Page number 37> 51. The fluidized bed according to claim 48 wherein said volumetric metering means includes a particulate collector defining a pre-selected volume.
52. The fluidized bed according to claim 51 wherein said particulate collector includes a collector plate having at least one cavity located in a front surface of said collector plate and having said pre-selected volume, said collector plate being positioned within said outlet passageway with said front facing toward said enclosure so particles from said fluidized bed accumulate in said at least one cavity.
53. The fluidized bed according to claim 51 wherein the said particulate collector includes a support plate and a blister plate mounted on a surface of said support plate, said. blister plate including at least one cavity of said pre-selected volume.
54. The fluidized bed according to claim 53 wherein said at least one cavity is a plurality of cavities each having a pre-selected volume, said cavities extending right through said blister plate, said support plate including holes through said plate and positioned so that when said blister plate is attached to said support plate the cavities in said blister plate are in registration with holes in said support plate, and including a porous filter sandwiched between said support plate and said blister plate for allowing gas to flow therethrough but not particulate matter.
55. The fluidized bed according to claim 54 wherein said particulate collector includes an elongate bar strip to which a plurality of support plates are detachably mountable with a back surface of each support plate mounted on a front surface of said elongate bar strip, a blister plate being mounted on a front surface of each support plate, and wherein said elongate bar strips are perforated at positions where said support plates are mountable. <Desc/Clms Page number 38> 56. The fluidized bed according to claim 55 including suction means engagable to a back surface of said elongate bar strip for applying suction to said particulate collector.
57. The fluidized bed according to claim 55 including a positioning mechanism for moving said elongate bar strip across said outlet passageway for positioning each of said blister plates mounted on said support member in said outlet passageway.
58. The fluidized bed according to claim 48 including agitation means operably coupled to said fluidized bed for agitating said particulate matter inside said housing.
59. The fluidized bed according to claim 58 wherein said agitation means is one of a vibration generator for transmitting vibrational energy to agitate said particulate matter, an ultrasonic wave generator for transmitting ultrasonic waves to agitate said particulate matter, and an acoustic wave generator for transmitting acoustic energy to said particulate matter.
60. The fluidized bed according to claim 58 wherein said agitation means includes a gas agitation means including a pressurized gas supply in communication with said enclosure for removing particulate matter adhering to interior walls of said housing.
61. The fluidized bed according to claim 60 wherein said gas agitation means includes at least one tube having one end connected to said pressurized gas supply and at least one nozzle attached to a free end of said tube located in a pre-selected position within said enclosure. <Desc/Clms Page number 39> 62. The fluidized bed according to claim 61 where said at least one tube is a plurality of tubes, each having a nozzle attached at its free end thereof, and wherein some of said tubes are made of rigid material.
63. The fluidized bed according to claim 62 wherein at least one of said plurality of tubes is made of a flexible material so that as gas is flowed through said tube with an effective gas pressure said free end with said nozzle attached thereto moves about within said enclosure.
64. The fluidized bed according to claim 2 wherein said outlet passageway for withdrawing pre-selected amounts of said particulate matter from said housing is located so that said particulate matter is withdrawn through said outlet passageway from said dilute phase.
65. The fluidized bed according to claim 2 wherein the fluidized bed is operated under conditions suitable to give a dense phase, and wherein said outlet passageway for withdrawing pre-selected amounts of said particulate matter from said housing is located so that said particulate matter is withdrawn from said dense phase.
66. The fluidized bed according to claim 16 including agitation means operably coupled to said fluidized bed for agitating said particulate matter inside said cylindrical housing.
67. The fluidized bed according to claim 17 including agitation means operably coupled to said fluidized bed for agitating said particulate matter inside said cylindrical housing.
68. The fluidized bed according to claim 18 including agitation means operably coupled to said fluidized bed for agitating said particulate matter inside said cylindrical housing. <Desc/Clms Page number 40> 69. The fluidized bed according to claim 16 including gas purging means in communication with said enclosure for removing particulate matter adhering to said housing.
70. The fluidized bed according to claim 17 including gas purging means in communication with said enclosure for removing particulate matter adhering to said housing.
71. The fluidized bed according to claim 18 including gas purging means in communication with said enclosure for removing particulate matter adhering to said housing.
72. The fluidized bed according to claim 16 wherein said volumetric metering means includes a particulate collector defining a pre-selected volume.
73. The fluidized bed according to claim 17 wherein said volumetric metering means includes a particulate collector defining a pre-selected volume.
74. The fluidized bed according to claim 18 wherein said volumetric metering means includes a particulate collector defining a pre-selected volume.
75. A fluidized bed for dispensing powders, comprising: a) a housing defining an enclosure for containing particulate matter, said housing including at least one porous wall having a suitable porosity to allow flow of fluid through said porous wall while preventing most of the particulate matter contained within said housing from passing through said porous wall, a fluid injection means for injecting a fluid into said enclosure for fluidizing particulate matter contained within said housing for forming either a dilute phase only or a dilute phase and a dense phase of fluidized powder in said housing; and <Desc/Clms Page number 41> b) time controlled powder withdrawal means connected to said housing and in flow communication with said enclosure through an outlet passageway for withdrawing particulate matter from said housing for a preselected period of time.
76. The fluidized bed according to claim 75 including air flow inducing means for inducing air flow patterns in said enclosure for reducing sticking of the particulate matter to the housing walls.
77. The fluidized bed according to claim 76 wherein said housing includes a cylinder having spaced end walls defining a cylindrical housing having a cylindrical axis, wherein said cylinder is porous, and including rotational drive means for rotating said cylinder about said cylindrical axis.
78. The fluidized bed according to claim 75 wherein said time controlled powder withdrawal means includes valve means in said outlet passageway connected to a timer for opening and closing said outlet passageway for controlling a length of time said particulate matter is withdrawn from said enclosure.
79. The fluidized bed according to claim 78 wherein said valve means is a solenoid located in said outlet passageway, and a control means connected to said solenoid for actuating said solenoid for opening and closing said outlet passageway.
80. The fluidized bed according to claim 25 where said at least one tube is a plurality of tubes, each having a nozzle attached at its free end thereof, and wherein some of said tubes are made of rigid material.
81. The fluidized bed according to claim 80 wherein at least one of said plurality of tubes is made of a flexible material so that as gas is flowed through <Desc/Clms Page number 42> said tube with an effective gas pressure said free end with said nozzle attached thereto moves about within said enclosure.
82. A fluidized bed for dispensing powders including a housing defining an enclosure for containing particulate matter, said housing including a fluid injection means for injecting a fluid into said enclosure for fluidizing particulate matter contained within said housing for forming a dilute phase alone or a dilute phase and a dense phase of fluidized powder in said housing, and volumetric metering means connected to said housing and in flow communication with said enclosure through an outlet passageway for withdrawing pre-selected amounts of said particulate matter from said housing.