US4699667A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removing residual PCB S from transformers
Assignee: ABB Inc USA
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Filing: 1983-11-14
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Granted: 1987-10-13
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Expires: 2003-11-14
Abstract
Abstract Disclosed is a method and apparatus for removing residual polychlorinated biphenyls from transformers. A vaporized solvent which forms a low-boiling azeotrope with polychlorinated biphenyls is passed through the transformer. The vaporized azeotrope is removed from the transformer, condensed, and the PCB's in the azeotrope are removed and/or destroyed. The apparatus includes means for vaporizing the solvent which forms the low-boiling azeotrope with the PCB's, a pump means for passing the vaporized solvent through the transformer, a condensing means for condensing the vaporized azeotrope, and treatment means for destroying the polychlorinated biphenyls removed from the transformer in the azeotrope.
Inventors
- 👤 Edward J. Walsh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:32
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/08; H01F27/10; H01F27/12; H01F27/14; C; C10; C10G; C10G21/00; C10G21/006; Y; Y10; Y10S; Y10S210/00; Y10S210/902; Y10S210/908; Y10S210/909
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
52 words
A method of removing residual polychlorinated biphenyls from apparatus comprising: (1) passing water vapor through said apparatus to form a low-boiling azeotrope of said polychlorinated biphenyls and said water vapor; (2) applying a vacuum to said apparatus to remove said azeotrope from said apparatus; and (3) cooling said azeotrope to a liquid.
Claim 2
Independent Claim
52 words
A method of removing residual polychlorinated biphenyls from apparatus comprising: (1) passing water vapor through said apparatus to form a low-boiling azeotrope of said polychlorinated biphenyls and said water vapor; (2) applying a vacuum to said apparatus to remove said azeotrope from said apparatus; and (3) cooling said azeotrope to a liquid.
Claim 3
Dependent Claim
21 words
A method according to claim 1 including collecting any polychlorinated biphenyl phase which separates from said liquid azeotrope, and destroying it.
Claim 4
Dependent Claim
23 words
A method according to claim 1 wherein the polychlorinated biphenyls in said liquid azeotrope are removed using activated carbon, and are then destroyed.
Claim 5
Dependent Claim
23 words
A method according to claim 1 wherein said polychlorinated biphenyls in said liquid azeotrope are destroyed in situ using ultraviolet light and ozone.
Claim 6
Dependent Claim
22 words
A method according to claim 1 wherein the application of said vacuum is alternated with passing said water vapor through said apparatus.
Claim 7
Dependent Claim
25 words
A method according to claim 5 wherein said alternating is continued until the temperature inside said apparatus is above the boiling point of said azeotrope.
Claim 8
Dependent Claim
12 words
A method according to claim 1 wherein said apparatus is a transformer.
References Cited (Backward Citations)
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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) | 1990-10-12 | 1991-04-13 | 1991-10-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-12 | 1995-04-13 | 1995-10-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-12 | 1999-04-13 | 1999-10-13 | $7700.00 | Window Closed / Lapsed |