Patent US4156604A successfully refreshed from Google Patents.
US4156604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled delivery of corrosion inhibitors for silver recovery cartridges
Assignee: 3M Co
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Filing: 1978-09-15
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Granted: 1979-05-29
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Expires: 1998-09-15
Abstract
Abstract A method for controlled delivery of corrosion inhibitors to a silver containing solution in a silver recovery device which utilizes a metallic fill for electron exchange. The method involves forming a structure of polyurethane foam within which a corrosion inhibitor is incorporated and placing the structure in the silver recovery device.
Inventors
- 👤 Richard S. Fisch
- 👤 Norman Newman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:14
CPC Classifications
C; C22; C22B; C22B11/00; C22B11/04; G; G03; G03C; G03C5/00; G03C5/26; G03C5/395; G03C5/3952
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
87 words
A method for controlled delivery of corrosion inhibitors to a silver containing solution in a silver recovery device which utilizes a metallic filler for electron exchange comprising the step of placing a polyurethane foam structure, which has incorporated therein a corrosion inhibitor, into the silver recovery device where the metallic filler contacts with the dormant silver solution, said structure being capable of releasing the corrosion inhibitor at a rate which yields a turbidity within the range of approximately 8 in 60 minutes to 20 in 15 minutes.
Claim 2
Independent Claim
87 words
A method for controlled delivery of corrosion inhibitors to a silver containing solution in a silver recovery device which utilizes a metallic filler for electron exchange comprising the step of placing a polyurethane foam structure, which has incorporated therein a corrosion inhibitor, into the silver recovery device where the metallic filler contacts with the dormant silver solution, said structure being capable of releasing the corrosion inhibitor at a rate which yields a turbidity within the range of approximately 8 in 60 minutes to 20 in 15 minutes.
Claim 3
Dependent Claim
19 words
A method for controlled delivery of corrosion inhibitors in accordance with claim 1 wherein said polyurethane foam is hydrophilic.
Claim 4
Dependent Claim
36 words
A method for controlled delivery of corrosion inhibitors in accordance with claim 1 wherein said polyurethane foam structure is a disk having a centrally disposed hole therethrough for positioning said disk in said silver recovery device.
Claim 5
Independent Claim
101 words
A method for controlled delivery of corrosion inhibitors to a silver containing solution in a silver recovery device which utilizes a metallic filler for electron exchange comprising the step of placing a metallic filler for electron exchange which has been coated with a polyurethane prepolymer which has incorporated therein a corrosion inhibitor, foaming said prepolymer on said coated portion of the metallic filler by exposing said prepolymer to H 2 O, said formed metallic filler releasing said corrosive inhibitor into the silver solution which yields a turbidity within the range of approximately 8 in 60 minutes to 20 in 15 minutes.
Claim 6
Independent Claim
101 words
A method for controlled delivery of corrosion inhibitors to a silver containing solution in a silver recovery device which utilizes a metallic filler for electron exchange comprising the step of placing a metallic filler for electron exchange which has been coated with a polyurethane prepolymer which has incorporated therein a corrosion inhibitor, foaming said prepolymer on said coated portion of the metallic filler by exposing said prepolymer to H 2 O, said formed metallic filler releasing said corrosive inhibitor into the silver solution which yields a turbidity within the range of approximately 8 in 60 minutes to 20 in 15 minutes.
Claim 7
Dependent Claim
19 words
A method for controlled delivery of corrosion inhibitors in accordance with claim 4 wherein said polyurethane foam is hydrophilic.
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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) | 1982-05-28 | 1982-11-27 | 1983-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-28 | 1986-11-27 | 1987-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-28 | 1990-11-27 | 1991-05-29 | $7700.00 | Window Closed / Lapsed |