US2826612A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of urea crystals
Assignee: Stamicarbon BV
•
Filing: 1956-01-03
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Granted: 1958-03-11
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Expires: 1976-01-03
Abstract
No abstract record available.
Inventors
- 👤 Over Klaas
- 👤 Leonardus J Rothkrans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:56
CPC Classifications
C; C07; C07C; C07C273/00; C07C273/02; C07C273/14; C07C273/16; B; B01; B01D; B01D9/00; B01D9/0018; B01D9/005; B01J; B01J2/00; B01J2/30; C05; C05C; C05C9/00; Y; Y10; Y10S; Y10S159/00; Y10S159/04; Y10S159/20
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
72 words
IN THE PREPARATION OF UREA CRYSTALS FROM AN AQUEOUS SOLUTION OF UREA CONTAINING 80-97% OF UREA BY STIRRING AND ADVANCING THE SOLUTION ALONG A CRYSTALLIZING VESSEL IN WHICH THE WATER IS EVAPORATED AND A SUBSTANTIALLY DRY CRYSTAL MASS OF UREA IS DISCHARGED, THE IMPROVEMENT COMPRISING ADDING TO THE UREA SOLUTION FROM 0.005 TO 1% OF AN ANION-ACTIVE, SURFACE-ACTIVE AGENT AS A FROTHING AGENT AND THEREBY CONVERTING THE SOLUTION TO A THICK FROTH.
Claim 2
Dependent Claim
72 words
IN THE PREPARATION OF UREA CRYSTALS FROM AN AQUEOUS SOLUTION OF UREA CONTAINING 80-97% OF UREA BY STIRRING AND ADVANCING THE SOLUTION ALONG A CRYSTALLIZING VESSEL IN WHICH THE WATER IS EVAPORATED AND A SUBSTANTIALLY DRY CRYSTAL MASS OF UREA IS DISCHARGED, THE IMPROVEMENT COMPRISING ADDING TO THE UREA SOLUTION FROM 0.005 TO 1% OF AN ANION-ACTIVE, SURFACE-ACTIVE AGENT AS A FROTHING AGENT AND THEREBY CONVERTING THE SOLUTION TO A THICK FROTH.
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) | 1961-03-10 | 1961-09-09 | 1962-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-03-10 | 1965-09-09 | 1966-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-03-10 | 1969-09-09 | 1970-03-11 | $7700.00 | Window Closed / Lapsed |