Patent US2709652A successfully refreshed from Google Patents.
US2709652A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acid sulfite pulping
Assignee: Celanese Corp
•
Filing: 1949-11-08
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Granted: 1955-05-31
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Expires: 1969-11-08
Abstract
No abstract record available.
Inventors
- 👤 Plunguian Mark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:13
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/04; D21C3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
97 words
IN A PROCESS FOR THE PREPARATION OF WOOD PULP, THE STEPS WHICH COMPRISE THOROUGHLY IMPREGNATING WOOD CHIPS WITH A SULFITE COOKING LIQUOR, CONTAINING AT LEAST ABOUT 1.5% OF COMBINED SO2 AND AT LEAST ABOUT 5% FREE SO2 BASED ON THE AMOUNT OF SULFITE COOKING LIQUOR, AT A TEMPERATURE OF 100 TO 120* C. AND AT SUPERATMOSPHERIC PRESSURE, AND THEN HEATING THE IMPREGNATED WOOD CHIPS TO A TEMPERATURE BETWEEN 190 AND 205* C. AND HELD AT THE PEAK TEMPERATURE FOR FROM 1 TO 3 MINUTES SO AS TO EFFECT THE DIGESTION OF THE WOOD CHIPS TO WOOD PULP.
Claim 2
Dependent Claim
97 words
IN A PROCESS FOR THE PREPARATION OF WOOD PULP, THE STEPS WHICH COMPRISE THOROUGHLY IMPREGNATING WOOD CHIPS WITH A SULFITE COOKING LIQUOR, CONTAINING AT LEAST ABOUT 1.5% OF COMBINED SO2 AND AT LEAST ABOUT 5% FREE SO2 BASED ON THE AMOUNT OF SULFITE COOKING LIQUOR, AT A TEMPERATURE OF 100 TO 120* C. AND AT SUPERATMOSPHERIC PRESSURE, AND THEN HEATING THE IMPREGNATED WOOD CHIPS TO A TEMPERATURE BETWEEN 190 AND 205* C. AND HELD AT THE PEAK TEMPERATURE FOR FROM 1 TO 3 MINUTES SO AS TO EFFECT THE DIGESTION OF THE WOOD CHIPS TO WOOD PULP.
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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) | 1958-05-30 | 1958-11-29 | 1959-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-05-30 | 1962-11-29 | 1963-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-05-30 | 1966-11-29 | 1967-05-31 | $7700.00 | Window Closed / Lapsed |