US3447333A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Helium film refrigerator
Assignee: California Institute Research Foundation
•
Filing: 1967-03-17
•
Granted: 1969-06-03
•
Expires: 1987-03-17
Abstract
No abstract record available.
Inventors
- 👤 David L Goodstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:01
CPC Classifications
F; F25; F25D; F25D3/00; F25D3/10
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US3166915A
Cited
US3192730A
Cited
US3176473A
Cited
US3302419A
Cited
US3314773A
Cited
US3358463A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1972-06-02 | 1972-12-02 | 1973-06-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1976-06-02 | 1976-12-02 | 1977-06-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1980-06-02 | 1980-12-02 | 1981-06-03 | $7700.00 | Window Closed / Lapsed |