Patent US1644180A successfully refreshed from Google Patents.
US1644180A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Direct-air heater
Assignee: Drying Systems Inc
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Filing: 1926-02-06
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Granted: 1927-10-04
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Expires: 1946-02-06
Abstract
No abstract record available.
Inventors
- 👤 Walter B Croan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:09
CPC Classifications
F; F24; F24H; F24H3/00; F24H3/02; F24H3/06; F24H3/08; F24H3/087
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) | 1930-10-03 | 1931-04-04 | 1931-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1934-10-03 | 1935-04-04 | 1935-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1938-10-03 | 1939-04-04 | 1939-10-04 | $7700.00 | Window Closed / Lapsed |