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US3585237A
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Crystallization of urea
Assignee: Wellman-Power Gas Inc
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Filing: 1966-09-29
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Granted: 1971-06-15
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Expires: 1986-09-29
Abstract
Abstract CRYSTALLINE UREA HAVING A LOW BIURET CONTENT AND A LOW BULK DENSITY IS PREPARED BY INTRODUCING A CONCENTRATED, AQUEOUS SOLUTION OF UREA TO A CRYSTALLIZATION ZONE UNDER CONDITIONS EFFECTING EVAPORATION OF SOME OF THE WATER FROM THE SOLUTION AND FORMATION OF UREA CRYSTALS ON THE SOLUTION SURFACE. THE CRYSTALS ARE SKIMMED FROM THE SOLUTION SURFACE ONTO A UREA-ADHERING SURFACE, FOR EXAMPLE, ONTO A ROTATING DRUM.
Inventors
- 👤 Jack D Terrana
- 👤 Leo A Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:49
CPC Classifications
C; C07; C07C; C07C273/00; C07C273/02; C07C273/14; C07C273/16; C05; C05C; C05C9/00; C05C9/005
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-14 | 1974-12-14 | 1975-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-14 | 1978-12-14 | 1979-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-14 | 1982-12-14 | 1983-06-15 | $7700.00 | Window Closed / Lapsed |