Patent US2813827A successfully refreshed from Google Patents.
US2813827A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Drilling fluids incorporating derivatives of lignitic materials
Assignee: Gulf Research and Development Co
•
Filing: 1953-12-29
•
Granted: 1957-11-19
•
Expires: 1973-12-29
Abstract
No abstract record available.
Inventors
- 👤 Edgar I Crowley
- 👤 Norman W Franke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 12:19
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/03; C09K8/032
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
60 words
A DRILLING FLUID HAVING INCORPORATED THEREIN A THINNING AMOUNT OF THE TOTAL PRODUCTS OBTAINED UPON REACTING A CLASS IV COAL WITH AN AQUEOUS ALKALINE SOLUTION AT A TEMPERATURE OF ABOUT 125*C., TO ABOUT 250*C. UNDER A PRESSURE SUFFICIENT TO MAINTAIN AN AQUEOUS PHASE FOR A SUFFICIENT TIME THAT LESS THAN ABOUT 70 PERCENT OF THE CLASS IV COAL REMAINS UNDISSOLVED.
Claim 2
Dependent Claim
60 words
A DRILLING FLUID HAVING INCORPORATED THEREIN A THINNING AMOUNT OF THE TOTAL PRODUCTS OBTAINED UPON REACTING A CLASS IV COAL WITH AN AQUEOUS ALKALINE SOLUTION AT A TEMPERATURE OF ABOUT 125*C., TO ABOUT 250*C. UNDER A PRESSURE SUFFICIENT TO MAINTAIN AN AQUEOUS PHASE FOR A SUFFICIENT TIME THAT LESS THAN ABOUT 70 PERCENT OF THE CLASS IV COAL REMAINS UNDISSOLVED.
References Cited (Backward Citations)
US2620300A
Cited
US2650197A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1960-11-18 | 1961-05-20 | 1961-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1964-11-18 | 1965-05-20 | 1965-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1968-11-18 | 1969-05-20 | 1969-11-19 | $7700.00 | Window Closed / Lapsed |