US3081152A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for calcination of gypsum
Assignee: United States Gypsum Co
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Filing: 1959-10-05
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Granted: 1963-03-12
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Expires: 1979-10-05
Abstract
No abstract record available.
Inventors
- 👤 Elmer S Johnson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:33
CPC Classifications
C; C04; C04B; C04B11/00; C04B11/02; C04B11/024
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
122 words
IN THE CALCINATION OF GYPSUM PARTICLES, SAID PARTICLES BEING SELECTED FROM THE GROUP CONSISTING OF GYPSUM PARTICLES, GYPSUM PPARTICLES WHICH ARE COATED WITH A SOLUTION OF A CRYSTAL-HABIT-MODIFIER, GYPSUM PARTICLES WHICH HAVE A CRYSTAL-HABIT-MODIFER SOLUTION PRECOLATED THERETHROUGH AND GYPSUM PARTICLES WHICH ARE MAINTAINED IN A SOLUTION OF A CRYSTAL-HABIT-MODIFIER THE STEPS COMPRISING SUBJECTING SAID PARTICLES TO AN INITAL SATURATED STEAM PRESSURE OF BETWEEN 15 AND 25 P.S.I.G UNTIL FORMATION OF CALCIUM SULFATE HEMIHYDRATE HAS BEEN INITIATED, INCREASING THE STEAM PRESSURE TO A PRESSURE GREATER THAN THE INITIAL PRESSURE BUT LESS THAN ABOUT 60 P.S.I.G. UNTIL CALCINATION IS COMPLETED IN LESS THAN 50% OF THE NORMAL CALCINATION TIME EXPENDED IN EFFECTING CALCINATION OF SAID TREATED GYPSUM PARTICLES AT SAID INITIAL SATURATED STEAM PRESSURE.
Claim 2
Dependent Claim
122 words
IN THE CALCINATION OF GYPSUM PARTICLES, SAID PARTICLES BEING SELECTED FROM THE GROUP CONSISTING OF GYPSUM PARTICLES, GYPSUM PPARTICLES WHICH ARE COATED WITH A SOLUTION OF A CRYSTAL-HABIT-MODIFIER, GYPSUM PARTICLES WHICH HAVE A CRYSTAL-HABIT-MODIFER SOLUTION PRECOLATED THERETHROUGH AND GYPSUM PARTICLES WHICH ARE MAINTAINED IN A SOLUTION OF A CRYSTAL-HABIT-MODIFIER THE STEPS COMPRISING SUBJECTING SAID PARTICLES TO AN INITAL SATURATED STEAM PRESSURE OF BETWEEN 15 AND 25 P.S.I.G UNTIL FORMATION OF CALCIUM SULFATE HEMIHYDRATE HAS BEEN INITIATED, INCREASING THE STEAM PRESSURE TO A PRESSURE GREATER THAN THE INITIAL PRESSURE BUT LESS THAN ABOUT 60 P.S.I.G. UNTIL CALCINATION IS COMPLETED IN LESS THAN 50% OF THE NORMAL CALCINATION TIME EXPENDED IN EFFECTING CALCINATION OF SAID TREATED GYPSUM PARTICLES AT SAID INITIAL SATURATED STEAM PRESSURE.
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) | 1966-03-11 | 1966-09-10 | 1967-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1970-03-11 | 1970-09-10 | 1971-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1974-03-11 | 1974-09-10 | 1975-03-12 | $7700.00 | Window Closed / Lapsed |