Patent US3423840A successfully refreshed from Google Patents.
US3423840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cone tray heat exchanger
Assignee: Dorr Oliver Inc
•
Filing: 1966-10-20
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Granted: 1969-01-28
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Expires: 1986-10-20
Abstract
No abstract record available.
Inventors
- 👤 David William Beeken
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 18:53
CPC Classifications
F; F28; F28C; F28C3/00; F28C3/10; F28C3/12; F28C3/16; F27; F27B; F27B15/00
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US248912A
Cited
US654093A
Cited
FR528407A
Cited
US1383921A
Cited
US2073553A
Cited
US2077346A
Cited
US2584312A
Cited
US2668041A
Cited
US2833622A
Cited
US3273257A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-01-28 | 1972-07-29 | 1973-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-01-28 | 1976-07-29 | 1977-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-01-28 | 1980-07-29 | 1981-01-28 | $7700.00 | Window Closed / Lapsed |