US3609943A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separator and process for the fractional desublimation of polycarboxylic acid anhydrides
Assignee: Gelsenberg Benzin AG
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Filing: 1968-12-09
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Granted: 1971-10-05
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Expires: 1988-12-09
Abstract
Abstract FOR THE DESUBLILMATION OF ACID ANHYDRIDES, A HEAT EXCHANGE IS PROVIDED CHARACTERIZED IN THAT THE RESIDENCE TIME DURING THE LATER PART OF THE DESUBLIMATION IS LONG RELATIVE TO THE RESIDENCE TIME DURING THE FIRST PART OF THE DESUBLILMATION.
Inventors
- 👤 Gunther Richter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:44
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/58; C07C51/60; B; B01; B01D; B01D7/00; B01D7/02; C07C51/54; C07C51/573; F; F28; F28D; F28D7/00; F28D7/02; F28D7/024; F28F; F28F27/00; F28F27/02
Claims Analysis
Total Claims: 0
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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) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |