Patent US3664918A successfully refreshed from Google Patents.
US3664918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vapor phase pulping of water saturated lignocellulosic materials
Assignee: FPInnovations
•
Filing: 1969-12-09
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Granted: 1972-05-23
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Expires: 1989-12-09
Abstract
Abstract Impregnating a water-saturated lignocellulosic material with an alkaline cooking liquor at a temperature below about 110* C., removing excess cooling liquor from the impregnated material, and delignifying the impregnated material by rapidly heating with steam.
Inventors
- 👤 David W Clayton
- 👤 Asahi Sakai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 13:42
CPC Classifications
D; D21; D21C; D21C1/00; D21C1/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
23 words
A process as claimed in claim 1 in which the impregnation is effected at a temperature in the range 60* to 90* C.
Claim 2
Dependent Claim
23 words
A process as claimed in claim 1 in which the impregnation is effected at a temperature in the range 70* to 90* C.
Claim 3
Dependent Claim
23 words
A process as claimed in claim 1 in which the delignification is effected at A temperature in the range 170* to 185* C.
Claim 4
Dependent Claim
21 words
A process as claimed in claim 1 in which the delignification is effected at a temperature of 170* to 175* C.
Claim 5
Dependent Claim
16 words
A process as claimed in claim 1 in which the impregnation liquor is a kraft liquor.
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) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |