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US4657667A
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Particle classifier
Assignee: University of Toronto Innovations Foundation
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Filing: 1984-04-05
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Granted: 1987-04-14
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Expires: 2004-04-05
Abstract
Abstract A particle classifier has a uniform, laminar, classifying air stream and a duct to introduce particulate material generally perpendicular to the air stream. The particulate material is entrained in a secondary air stream that is diverted as it enters the classifying air stream by a curved surface. The curved surface produces and diverts the air stream by the Coanda effect to minimize disturbance to the classifying air and segregate the particles from the secondary air.
Inventors
- 👤 Bernard Etkin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:47
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/02; G01N15/0255; B; B07; B07B; B07B11/00; B07B11/04; B07B11/06; B07B4/00; B07B4/02; B07B7/00; B07B7/01; B07B7/08; B07B7/086; B07B7/0865
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
178 words
A classifier for particulate material comprising a housing having an inlet to receive a classifying air flow flowing in a given direction, collection means downstream of said inlet to receive material classified by said air flow, and material introduction means intermediate said inlet and said collection means to introduce particles entrained in a secondary air stream into said housing in a direction other than said given direction, said material introduction means including a material outlet aperture in a wall of said housing extending generally perpendicular to said given direction, conveying means to convey material and said secondary air stream to said material outlet and diverting means to divert said secondary air stream to a direction generally parallel to said classifying air flow flowing in said given direction, said diverting means including a surface extending downstream from said outlet and adjacent thereto and being dimensioned to divert said secondary airstream by a Coanda effect generally parallel to said given direction and thereby segregate said secondary air/stream from said particles and permit continued movement of said particles along predictable trajectories.
Claim 2
Dependent Claim
178 words
A classifier for particulate material comprising a housing having an inlet to receive a classifying air flow flowing in a given direction, collection means downstream of said inlet to receive material classified by said air flow, and material introduction means intermediate said inlet and said collection means to introduce particles entrained in a secondary air stream into said housing in a direction other than said given direction, said material introduction means including a material outlet aperture in a wall of said housing extending generally perpendicular to said given direction, conveying means to convey material and said secondary air stream to said material outlet and diverting means to divert said secondary air stream to a direction generally parallel to said classifying air flow flowing in said given direction, said diverting means including a surface extending downstream from said outlet and adjacent thereto and being dimensioned to divert said secondary airstream by a Coanda effect generally parallel to said given direction and thereby segregate said secondary air/stream from said particles and permit continued movement of said particles along predictable trajectories.
Claim 3
Dependent Claim
11 words
A classifier according to claim 1 wherein said surface is curved.
Claim 4
Dependent Claim
36 words
A classifier according to claim 2 wherein said material outlet is an elongated slit and said curved surface extends from a downstream edge of said slit to merge smoothly with an adjacent wall of said housing.
Claim 5
Dependent Claim
28 words
A classifier according to claim 3 wherein said conveying means includes a duct having a pair of laterally extending walls coincident with the lateral edges of said slit.
Claim 6
Dependent Claim
22 words
A classifier according to claim 4 wherein said duct is of constant cross section and said walls diverge away from said slit.
Claim 7
Dependent Claim
21 words
A classifier according to claim 5 wherein said duct includes an abrupt change in direction to reduce agglomeration of said material.
Claim 8
Dependent Claim
41 words
A classifier according to claim 3 wherein said collection means includes a plurality of discrete passages each having an inlet defined by a pair of parallel partitions having their leading edges generally transverse to the direction of introduction of said material.
Claim 9
Dependent Claim
52 words
A classifier according to claim 7 wherein each of said passages includes flow control means to ad,just the flow rate in each passage and maintain the ratio of the flow rates in said passages proportional to the ratio of the area of said classifying flow intercepted by said partitions of each passage.
Claim 10
Dependent Claim
26 words
A classifier according to claim 7 wherein each of said partitions has a tapered leading edge to present a knife edge to said classifying air flow.
Claim 11
Dependent Claim
40 words
A classifier according to claim 9 wherein at least some of said partitions are oriented so that the axis of the passage defined between such partitions is generally parallel to the trajectory of a particle of material entering said passage.
Claim 12
Dependent Claim
18 words
A classifier according to claim 2 wherein said curved surface is of constant radius and extends through 90°.
Claim 13
Dependent Claim
158 words
A classifier for particulate material comprising a generally horizontal housing having an inlet to receive a classifying air flow flowing in a given direction, a collection means downstream of said inlet to receive classified material, an elongate slit in an upper surface of said housing extending generally perpendicular to the direction of said classifying air flow, material introduction means intermediate said inlet and said collection means to introduce particles entrained in a secondary air stream into said housing, a flow diverting surface projecting into said housing from a downstream edge of said slit, said material introduction means arranged to deliver said material entrained in the secondary air stream to said slit in a generally vertical direction, said slit and said diverting surface being selected to divert said secondary air stream through substantially 90° to a direction parallel with said classifying air flow by virtue of the Coanda effect produced on said secondary air stream by said diverting surface.
Claim 14
Dependent Claim
158 words
A classifier for particulate material comprising a generally horizontal housing having an inlet to receive a classifying air flow flowing in a given direction, a collection means downstream of said inlet to receive classified material, an elongate slit in an upper surface of said housing extending generally perpendicular to the direction of said classifying air flow, material introduction means intermediate said inlet and said collection means to introduce particles entrained in a secondary air stream into said housing, a flow diverting surface projecting into said housing from a downstream edge of said slit, said material introduction means arranged to deliver said material entrained in the secondary air stream to said slit in a generally vertical direction, said slit and said diverting surface being selected to divert said secondary air stream through substantially 90° to a direction parallel with said classifying air flow by virtue of the Coanda effect produced on said secondary air stream by said diverting surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-13 | 1990-10-13 | 1991-04-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-13 | 1994-10-13 | 1995-04-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-13 | 1998-10-13 | 1999-04-14 | $7700.00 | Window Closed / Lapsed |