US2604447A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aqueous well-drilling fluids
Assignee: NL Industries Inc
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Filing: 1948-07-29
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Granted: 1952-07-22
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Expires: 1968-07-29
Abstract
No abstract record available.
Inventors
- 👤 George W Cummer
- 👤 Delmar H Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:09
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/02; C09K8/04; C09K8/14; C09K8/18; C09K8/20; C09K8/206
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
41 words
AN AQUEOUS WELL-DRILLING FLUID CONTAINING SUFFICIENT OF A MODIFIED-STARCH-DEXTRINE PRODUCED BY SUBJECTING A STARCHY MATERIAL TO A TEMPERATURE OF 220-250* C. FOR A SHORT PERIOD, ABOUT FIFTEEN MINUTES, FOLLOWED BY ALLOWING THE SAME TO COOL, TO ATTAIN A LOW WATER LOSS.
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) | 1955-07-22 | 1956-01-21 | 1956-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-07-22 | 1960-01-21 | 1960-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-07-22 | 1964-01-21 | 1964-07-22 | $7700.00 | Window Closed / Lapsed |