US2959555A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Copper and iron containing scale removal from ferrous metal
Assignee: Dow Chemical Co
•
Filing: 1957-05-23
•
Granted: 1960-11-08
•
Expires: 1977-05-23
Abstract
No abstract record available.
Inventors
- 👤 Robert C Martin
- 👤 William T Abel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 03:43
CPC Classifications
C; C23; C23G; C23G1/00; C23G1/02; C23G1/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
119 words
THE METHOD OF REMOVING A COPPER AND IRON OXIDE CONTAINING INCRUSTATION FROM A FERROUS METAL SURFACE WITHOUT REDEPOSITION OF COPPER THEREON WHICH CONSISTS IN BRINGING INTO CONTACT WITH SUCH SURFACES AN AQUEOUS SOLUTION CONSISTING OF WATER IN WHICH IS DISSOLVED FROM 5 TO 25 PERCENT BY WEIGHT OF HYDROCHLORIC ACID, THIOUREA, AND FROM 0.1 TO 1 PERCENT OF AN ORGNIC NITROGEN BASE OTHER THAN THIOUREA CAPABLE OF INHIBITING THE CORROSIVE ACTION OF THE ACID ON FERROUS METAL, THE AMOUNT OF THE THIOUREA BEING IN EXCESS OF 0.01 PERCENT BY WEIGHT OF THE SOLUTION AND BETWEEN 2 AND 20 TIMES THE WEIGHT OF THE COPPER TO BE REMOVED, THE VOLUME OF TE AQUEOUS SOLUTION BEING SUFFICIENT TO REMOVE THE INCRUSTATIONS.
Claim 2
Dependent Claim
98 words
A COMPOSITION FOR REMOVING COPPER CONTAINING IRON OXIDE INCRUSTATIONS FROM A FERROUS METAL SURFACE CONSISTING OF A SOLUTION IN WATER OF FROM 2 TO 25 PERCENT BY WEIGHT OF HYDROCHLORIC ACID, A UREA DERIVATIVE SELECTED FROM THE GROUP CONSISTING OF THIOUREA, 1,3-DIMETHYL THIOUREA, ETHYLENE THIOUREA, 1,3-DIETHYL THIOUREA, 1,3-DIISOPROPYL THIOUREA IN THE AMOUNT OF AT LEAST 0.67 PERCENT BY WEIGHT, AND FROM 0.1 TO 1 PERCENT OF AN ORGANIC NITROGEN BASE SOLUBLE IN THE SOLUTION SELECTED FROM THE GROUP CONSISTING OF THE AROMATIC AND HETEROCYCLIC NITROGEN BASES CAPABLE OF INHIBITING THE CORROSIVE ACTION OF THE ACID ON FERROUS METAL.
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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) | 1963-11-08 | 1964-05-09 | 1964-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-11-08 | 1968-05-09 | 1968-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-11-08 | 1972-05-09 | 1972-11-08 | $7700.00 | Window Closed / Lapsed |