Patent US2528349A successfully refreshed from Google Patents.
US2528349A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alkaline sulfite digestion of hardwood
Assignee: Hardwood By-Products Inc
•
Filing: 1945-02-27
•
Granted: 1950-10-31
•
Expires: 1965-02-27
Abstract
No abstract record available.
Inventors
- 👤 Farber Eduard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:08
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
59 words
A PROCESS FOR EXTRACTING HEMICELLULOSES, LIGNIN, PENTOSANS AND SIMILAR BONDING AGENTS FROM HARDWOOD TO PRODUCE A PULP WHICH CONSISTS ESSENTIALLY OF SUBJECTING AT ATMOSPHERIC PRESSURE AND AT A TEMPERATURE OF ABOUT 40*C. HARDWOOD PARTICLES TO THE ACTION OF AN AQUEOUS SOLUTION CONSISTING ESSENTIALLY OF ABOUT 0.5% BY WEIGHT OF BOTH AN ALKALI METAL HYDROXIDE AND AN ALKALI METAL SULFITE.
References Cited (Backward Citations)
US66338A
Cited
US1501925A
Cited
US1389936A
Cited
US1631834A
Cited
US1682834A
Cited
US1654624A
Cited
US1859848A
Cited
US1846511A
Cited
US1936697A
Cited
US1873056A
Cited
US2188533A
Cited
US2247204A
Cited
US2292390A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-10-30 | 1954-05-01 | 1954-10-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-10-30 | 1958-05-01 | 1958-10-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-10-30 | 1962-05-01 | 1962-10-31 | $7700.00 | Window Closed / Lapsed |