US4435183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for rapid dewatering and drying of calcium sulfate hemihydrate
Assignee: UNITED STATE GYPSUM COMPANY 101 SOUTH WACKER DRIVE CHICAGO ILL 60606 A CORP
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Filing: 1982-02-16
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Granted: 1984-03-06
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Expires: 2002-02-16
Abstract
Abstract A process for rapidly dewatering and drying calcium sulfate hemihydrate in a centrifuging and flash drying operation by ejecting the wet solids from the centrifuge bowl directly into the flash dryer's high velocity, high volume, heated air stream.
Inventors
- 👤 Donald O. Baehr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:08
CPC Classifications
F; F26; F26B; F26B5/00; F26B5/08; C; C04; C04B; C04B11/00; C04B11/02; C04B11/028; C04B11/032; F26B17/00; F26B17/10; F26B17/101; F26B17/103; F26B20/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
93 words
A process for rapid mechanical dewatering and thermal drying of a calcium sulfate hemihydrate slurry in a centrifuging and flash drying operation comprising: enclosing the discharge end of a centrifuge bowl within a high velocity, high volume, heated air stream of a flash dryer; passing high velocity, high volume heated air through the dryer; ejecting damp hemihydrate solids directly from the centrifuge bowl lip into the high velocity, high volume heated air stream of the flash dryer; and suspending the hemihydrate solids in the high velocity, high volume heated air stream until dry.
Claim 2
Dependent Claim
93 words
A process for rapid mechanical dewatering and thermal drying of a calcium sulfate hemihydrate slurry in a centrifuging and flash drying operation comprising: enclosing the discharge end of a centrifuge bowl within a high velocity, high volume, heated air stream of a flash dryer; passing high velocity, high volume heated air through the dryer; ejecting damp hemihydrate solids directly from the centrifuge bowl lip into the high velocity, high volume heated air stream of the flash dryer; and suspending the hemihydrate solids in the high velocity, high volume heated air stream until dry.
Claim 3
Dependent Claim
24 words
The process of claim 1 in which the high velocity, high volume air stream is at a temperature of at least about 400° F.
Claim 4
Dependent Claim
21 words
The process of claim 1 in which the air stream is at a temperature of between about 400° and 1200° F.
Claim 5
Dependent Claim
21 words
The process of claim 3 in which the air stream is at a temperature of between about 400° and 800° F.
Claim 6
Dependent Claim
25 words
The process of claim 1 in which the high volume, heated air is provided at a velocity of at least about 3500 feet per minute.
Claim 7
Dependent Claim
36 words
The process of claim 1 in which the high velocity heated air is provided in an amount of at least about 8 pounds of air per pound of water to be evaporated from the damp solids.
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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) | 1987-03-06 | 1987-09-05 | 1988-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-06 | 1991-09-05 | 1992-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-06 | 1995-09-05 | 1996-03-06 | $7700.00 | Window Closed / Lapsed |