Patent US3666581A successfully refreshed from Google Patents.
US3666581A
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US
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Method of making dried gypsum articles having improved strength to density ratio
Assignee: United States Gypsum Co
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Filing: 1969-04-01
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Granted: 1972-05-30
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Expires: 1989-04-01
Abstract
Abstract THE PROCESS OF MAKING DRIED GYPSUM ARTICLES HAVING AN INCREASED STRENGTH TO DENSITY RATIO AND WHICH CAN BE CAST FROM AN AQUEOUS SLURRY OF CALCINED GYPSUM THAT CONTAINS LESS WATER FOR THE SAME FLUIDITY, BY PROVIDING A SPECIALLY SIZED CALCINED GYPSUM WHICH CONTAINS 0% TO 7% BY WEIGHT OF PARTICLES LARGER THAN 32 MICRONS AND 0% TO 8% BY WEIGHT OF PARTICLES SMALLER THAN 1 MICRON, FORMING A SLURRY AT USABLE FLUIDITY AFTER MIXING VIGOROUSLY WITH ACCELERATOR AND CASTING WHILE THE SIZED CALCINED GYPSUM HAS A COMBINED MOISTURE CONTENT OF LESS THAN 9% BY WEIGHT.
Inventors
- 👤 Marvin K Lane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:22
CPC Classifications
C; C04; C04B; C04B11/00; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1089; Y10T156/1092; Y10T156/1093; Y10T428/00; Y10T428/25; Y10T428/31504; Y10T428/31971; Y10T428/31993; Y10T428/31996
Claims Analysis
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References Cited (Backward Citations)
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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) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |