US3438431A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchanger system
Assignee: Individual
•
Filing: 1967-08-25
•
Granted: 1969-04-15
•
Expires: 1987-08-25
Abstract
No abstract record available.
Inventors
- 👤 Siegfried Dreyer
- 👤 Rudolf Harde
- 👤 Walter Jansing
- 👤 Friedel Kalkoffen
- 👤 Hans Mausbeck
- 👤 Werner Schnittker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 05:37
CPC Classifications
F; F22; F22B; F22B1/00; F22B1/02; F22B1/06; F22B1/063
Claims Analysis
Total Claims: 0
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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) | 1972-04-14 | 1972-10-14 | 1973-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-04-14 | 1976-10-14 | 1977-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-04-14 | 1980-10-14 | 1981-04-15 | $7700.00 | Window Closed / Lapsed |