US2724307A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of wood-fiber hardboard
Assignee: National Gypsum Co
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Filing: 1954-09-23
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Granted: 1955-11-22
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Expires: 1974-09-23
Abstract
No abstract record available.
Inventors
- 👤 Basil O Stewart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:04
CPC Classifications
D; D21; D21C; D21C3/00; D21C3/22; D21J; D21J1/00
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
113 words
A METHOD OF MAKING HEAT-CONSOLIDATED WOOD-FIBER HARDBOARD COMPRISING THE STEPS OF FRAGMENTIZING RAW WOOD, SUBJECTING SAID FRAGMENTIZED WOOD IN A PRESSURETIGHT CONTAINER TO A HIGH TEMPERATURE-PRESSURE CONVERSION IN AN AQUEOUS LIQUOR FORMED BY A PLURALITY OF PRIOR CONVERSIONS AND ONLY SUFFICIENT MAKE-UP WATER TO MAINTAIN THE CHIPS FREELY DISPERSED THEREIN, SAID CONVERSION COMPRISING THE STEPS OF A RAPID RISE IN TEMPERATURE TO FROM 190* TO 250* C., MAINTAINING SAID HIGH TEMPERATURE AND THE SUPER-ATMOSPHERIC PRESSURE PRODUCED THEREBY FOR A PERIOD OF FROM 5 TO 30 MINUTES, THEREAFTER RAPIDLY SEPARATING SAID WOOD FROM SAID LIQUOR, REDUCING SAID WOOD SUBSTANTIALLY TO FIBERS, FORMING A MAT THEREFROM AND CONSOLIDATING SAID MAT BY SUITABLE HEAT AND PRESSURE.
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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) | 1958-11-21 | 1959-05-23 | 1959-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-11-21 | 1963-05-23 | 1963-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-11-21 | 1967-05-23 | 1967-11-22 | $7700.00 | Window Closed / Lapsed |