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Patent US3353995A successfully refreshed from Google Patents.
US3353995A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of ferrous sulfide deposits
Assignee: Dow Chemical Co
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Filing: 1964-03-26
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Granted: 1967-11-21
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Expires: 1984-03-26
Abstract
No abstract record available.
Inventors
- 👤 Teumac Fred Norman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:18
CPC Classifications
C; C23; C23G; C23G1/00; C23G1/02; C23G1/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
116 words
A METHOD OF REMOVING FERROUS SULFIDE FROM FERROUS METAL SURFACES COMPRISING PROVIDING AN AQUEOUS SOLUTION CONTAINING FROM ABOUT ONE TO ABOUT TEN PERCENT BY WEIGHT OF AN ACID SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC AND SULFURIC ACIDS, FROM ABOUT 0.1 TO ABOUT 1.0 PERCENT BY WEIGHT OF COPPER ION, AND A THIOUREA COMPOUND SELECTED FROM THE GROUP CONSISTING OF THIOUREA, 1,3DIMETHYL THIOUREA, 1,3-DIETHYL THIOUREA, ALLYL THIOUREA, ETHYLENE THIOUREA, AND 1,3-DIISOPROPYL THIOUREA, SAID THIOUREA COMPOUND BEING PRESENT IN AN AMOUNT EQUIVALENT TO AN AMOUNT OF THIOUREA FROM ABOUT 2 TO ABOUT 20 TIMES THE WEIGHT OF COPPER ION PRESENT, AND CONTACTING THE FERROUS SULFIDE-CONTAINING FERROUS METAL SURFACE WITH SAID AQUEOUS SOLUTION, THEREBY TO REMOVE FERROUS SULFIDE.
Claim 2
Independent Claim
116 words
A METHOD OF REMOVING FERROUS SULFIDE FROM FERROUS METAL SURFACES COMPRISING PROVIDING AN AQUEOUS SOLUTION CONTAINING FROM ABOUT ONE TO ABOUT TEN PERCENT BY WEIGHT OF AN ACID SELECTED FROM THE GROUP CONSISTING OF HYDROCHLORIC AND SULFURIC ACIDS, FROM ABOUT 0.1 TO ABOUT 1.0 PERCENT BY WEIGHT OF COPPER ION, AND A THIOUREA COMPOUND SELECTED FROM THE GROUP CONSISTING OF THIOUREA, 1,3DIMETHYL THIOUREA, 1,3-DIETHYL THIOUREA, ALLYL THIOUREA, ETHYLENE THIOUREA, AND 1,3-DIISOPROPYL THIOUREA, SAID THIOUREA COMPOUND BEING PRESENT IN AN AMOUNT EQUIVALENT TO AN AMOUNT OF THIOUREA FROM ABOUT 2 TO ABOUT 20 TIMES THE WEIGHT OF COPPER ION PRESENT, AND CONTACTING THE FERROUS SULFIDE-CONTAINING FERROUS METAL SURFACE WITH SAID AQUEOUS SOLUTION, THEREBY TO REMOVE FERROUS SULFIDE.
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) | 1970-11-20 | 1971-05-22 | 1971-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-11-20 | 1975-05-22 | 1975-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-11-20 | 1979-05-22 | 1979-11-21 | $7700.00 | Window Closed / Lapsed |