US2578338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Paraformaldehyde production with countercurrent concentration
Assignee: EIDP Inc
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Filing: 1949-04-21
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Granted: 1951-12-11
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Expires: 1969-04-21
Abstract
No abstract record available.
Inventors
- 👤 Robert L Craven
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:13
CPC Classifications
C; C08; C08G; C08G2/00; C08G2/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
87 words
THE PROCESS FOR THE PRODUCTION OF PARAFORMALDEHYDE WHICH COMPRISES PASSING METHANOL CONVERSION GASES HAVING AN INITIAL TEMPERATURE BETWEEN 200* C. AND 300* C. IN SUCCESSION THROUGH A SERIES OF PROGRESSIVELY LESS CONCENTRATED FRACTIONS OF AQUEOUS SOLUTIONS OF FORMALDEHYDE IN A PLATE COLUMN, SAID AQUEOUS SOLUTIONS OF FORMALDEHYDE FLOWING FROM PLATE TO PLATE IN SAID COLUMN IN A DIRECTION OPPOSITE TO THE FLOW OF SAID GASES WHEREBY THE FRACTIONS BECOME PROGRESSIVELY MORE CONCENTRATED IN FORMALDEHYDE, SAID FRACTIONS BEING SUFFICIENT TO NUMBER TO CONCENTRATE THE FORMALDEHYDE TO LIQUID PARAFORMALDEHYDE.
Claim 2
Dependent Claim
87 words
THE PROCESS FOR THE PRODUCTION OF PARAFORMALDEHYDE WHICH COMPRISES PASSING METHANOL CONVERSION GASES HAVING AN INITIAL TEMPERATURE BETWEEN 200* C. AND 300* C. IN SUCCESSION THROUGH A SERIES OF PROGRESSIVELY LESS CONCENTRATED FRACTIONS OF AQUEOUS SOLUTIONS OF FORMALDEHYDE IN A PLATE COLUMN, SAID AQUEOUS SOLUTIONS OF FORMALDEHYDE FLOWING FROM PLATE TO PLATE IN SAID COLUMN IN A DIRECTION OPPOSITE TO THE FLOW OF SAID GASES WHEREBY THE FRACTIONS BECOME PROGRESSIVELY MORE CONCENTRATED IN FORMALDEHYDE, SAID FRACTIONS BEING SUFFICIENT TO NUMBER TO CONCENTRATE THE FORMALDEHYDE TO LIQUID PARAFORMALDEHYDE.
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) | 1954-12-10 | 1955-06-11 | 1955-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-12-10 | 1959-06-11 | 1959-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-12-10 | 1963-06-11 | 1963-12-11 | $7700.00 | Window Closed / Lapsed |