US3426420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making brazed composite tubing for heat exchangers used in corrosive fluids
Assignee: National Research Corp
•
Filing: 1966-04-08
•
Granted: 1969-02-11
•
Expires: 1986-04-08
Abstract
No abstract record available.
Inventors
- 👤 Foster R Grant
- 👤 Maurice L Torti Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:10
CPC Classifications
B; B23; B23K; B23K35/00; B23K35/001; B23K35/007; B23K1/00; B23K1/19; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12333; Y10T428/12493; Y10T428/12771; Y10T428/12806; Y10T428/12819; Y10T428/12861; Y10T428/12903
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-02-11 | 1972-08-12 | 1973-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-02-11 | 1976-08-12 | 1977-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-02-11 | 1980-08-12 | 1981-02-11 | $7700.00 | Window Closed / Lapsed |