Patent US5289922A successfully refreshed from Google Patents.
US5289922A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic separation of mixed plastic waste
Assignee: University of Western Ontario
•
Filing: 1992-09-28
•
Granted: 1994-03-01
•
Expires: 2012-09-28
Abstract
Abstract A mixture of particles of plastic materials having different work functions is fed through a rotating tube. The tube rotates about an axis which is inclined slightly to the horizontal. The tube is of plastic or metallic material, preferably having a rib for stirring the mixture. As the particles pass progressively down the length of the tube, the triboelectrically induced charge progressively increases, whereby the particles are highly charged upon emerging from the tube. The tube may be made of the same material as a minority component of the mixture to bring up the level of the charge on the majority component.
Inventors
- 👤 Ion I. Inculet
- 👤 G. S. P. Castle
- 👤 James D. Brown
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:33
CPC Classifications
B; B03; B03C; B03C7/00; B03C7/006; B29; B29B; B29B17/00; B29B17/02; B29B2017/0203; B29B2017/0213; B29B2017/0262; B29B2017/0265; B29K; B29K2023/00; B29K2023/04; B29K2023/06; B29K2023/10; B29K2023/12; Y; Y02; Y02W; Y02W30/00; Y02W30/50; Y02W30/52; Y02W30/62
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
123 words
An apparatus for tribocharging particles of electrically insulating materials, the apparatus comprising a tube rotatable about its longitudinal axis and inclined at an angle to the horizontal, the particles being adapted to be gradually and progressively moved longitudinally through the tube from an entry point to an exit point, movement of the particles through the tube resulting in the particles making contact with the tube and with each other, the tube being formed from a material with an electrostatic work function that is different from that of the particles, the difference in the electrostatic work function between the tube and the particles resulting in the particles becoming increasingly tribocharged as they move from the entry point to the exit point on the tube.
Claim 2
Independent Claim
123 words
An apparatus for tribocharging particles of electrically insulating materials, the apparatus comprising a tube rotatable about its longitudinal axis and inclined at an angle to the horizontal, the particles being adapted to be gradually and progressively moved longitudinally through the tube from an entry point to an exit point, movement of the particles through the tube resulting in the particles making contact with the tube and with each other, the tube being formed from a material with an electrostatic work function that is different from that of the particles, the difference in the electrostatic work function between the tube and the particles resulting in the particles becoming increasingly tribocharged as they move from the entry point to the exit point on the tube.
Claim 3
Dependent Claim
37 words
An apparatus as in claim 1, and also comprising a feeding means for feeding particles into the entry point on the tube, and a receiving means for receiving charged particles from the exit point on the tube.
Claim 4
Dependent Claim
38 words
An apparatus as in claim 1, and also comprising a speed adjustment means for adjusting the rotational speed of the tube, and an angle adjustment means for adjusting the longitudinal axis angle of the tube to the horizontal.
Claim 5
Dependent Claim
14 words
An apparatus as in claim 1, wherein the tube is of right cylindrical cross-section.
Claim 6
Dependent Claim
33 words
An apparatus as in claim 1, wherein the tube includes at least one rib extending radially inward from the inside surface of the tube, the rib extending the axial length of the tube.
Claim 7
Dependent Claim
32 words
An apparatus as in claim 1, in combination with a mixture of particles of plastic materials, the tube being of the same material as a minority of the particles in the mixture.
Claim 8
Dependent Claim
74 words
An apparatus as in claim 1, 2 or 3, and further comprising a separation means, the separation means comprising a channel and high voltage electrodes, the channel being positioned in line with the exit end of the tube and having at least one opening along its bottom for particles to drop through, the high voltage electrodes being arranged vertically on either side of the channel and extending therealong and downwardly to separate the particles.
Claim 9
Dependent Claim
74 words
An apparatus as in claim 4, 5 or 6, and further comprising a separation means, the separation means comprising a channel and high voltage electrodes, the channel being positioned in line with the exit end of the tube and having at least one opening along its bottom for particles to drop through, the high voltage electrodes being arranged vertically on either side of the channel and extending therealong and downwardly to separate the particles.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-02-28 | 1997-08-30 | 1998-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-02-28 | 2001-08-30 | 2002-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-02-28 | 2005-08-30 | 2006-03-01 | $7700.00 | Window Closed / Lapsed |