Patent US2721730A successfully refreshed from Google Patents.
US2721730A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat exchanger
Assignee: Mersen SA
•
Filing: 1952-10-29
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Granted: 1955-10-25
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Expires: 1972-10-29
Abstract
No abstract record available.
Inventors
- 👤 Clause Jean
- 👤 Parisot Jean
- 👤 Roos Charles
- 👤 Hilliard Alfred
- 👤 Jaray Francis Ferdinand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:46
CPC Classifications
F; F28; F28F; F28F7/00; F28F7/02; F28D; F28D11/00; Y; Y10; Y10S; Y10S165/00; Y10S165/135; Y10S165/139; Y10S165/14
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US99070A
Cited
US436337A
Cited
US781529A
Cited
US924233A
Cited
US1281351A
Cited
US1645614A
Cited
US1854213A
Cited
GB664464A
Cited
DE805638C
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-10-24 | 1959-04-25 | 1959-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-24 | 1963-04-25 | 1963-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-24 | 1967-04-25 | 1967-10-25 | $7700.00 | Window Closed / Lapsed |