US3248269A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scale removal
Assignee: Pfizer Inc
•
Filing: 1962-08-15
•
Granted: 1966-04-26
•
Expires: 1982-08-15
Abstract
No abstract record available.
Inventors
- 👤 William E Bell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:29
CPC Classifications
C; C23; C23G; C23G1/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
73 words
THE METHOD OF REMOVING COPPER-CONTAINING IRON OXIDE SCALE FROM METAL SURFACES CONSISTING ESSENTIALLY OF CONTACTING SAID SURFACES WITH A COMPOSITION COMPRISING A SUBSTANTIALLY NEUTRAL AQUEOUS SOLUTION OF AMMONIUM CITRATE, CONTINUING SAID CONTACT UNTIL THE IRON CONTENT OF SAID SOLUTION BECOMES SUBSTANTIALLY CONSTANT AS THE PH RISES, THEN CONTINUING SAID CONTACT AT A PH OF AT LEAST 9 AND MAINTAINING SAID PH WITH AMMONIA UNTIL THE COPPER CONTENT OF SAID SOLUTION BECOMES SUBSTANTIALLY CONSTANT.
Claim 2
Independent Claim
73 words
THE METHOD OF REMOVING COPPER-CONTAINING IRON OXIDE SCALE FROM METAL SURFACES CONSISTING ESSENTIALLY OF CONTACTING SAID SURFACES WITH A COMPOSITION COMPRISING A SUBSTANTIALLY NEUTRAL AQUEOUS SOLUTION OF AMMONIUM CITRATE, CONTINUING SAID CONTACT UNTIL THE IRON CONTENT OF SAID SOLUTION BECOMES SUBSTANTIALLY CONSTANT AS THE PH RISES, THEN CONTINUING SAID CONTACT AT A PH OF AT LEAST 9 AND MAINTAINING SAID PH WITH AMMONIA UNTIL THE COPPER CONTENT OF SAID SOLUTION BECOMES SUBSTANTIALLY CONSTANT.
References Cited (Backward Citations)
US1050678A
Cited
US2428364A
Cited
US2935428A
Cited
US2900285A
Cited
US2890974A
Cited
US3038824A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-04-25 | 1969-10-25 | 1970-04-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-04-25 | 1973-10-25 | 1974-04-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-04-25 | 1977-10-25 | 1978-04-26 | $7700.00 | Window Closed / Lapsed |