US2677439A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Collection of suspended particles
Assignee: Research Corp
•
Filing: 1952-11-20
•
Granted: 1954-05-04
•
Expires: 1972-11-20
Abstract
No abstract record available.
Inventors
- 👤 Carl W J Hedberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:54
CPC Classifications
B; B01; B01D; B01D51/00; B01D51/10; C; C09; C09C; C09C1/00; C09C1/44; C09C1/48; C09C1/487
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) | 1957-05-03 | 1957-11-02 | 1958-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-05-03 | 1961-11-02 | 1962-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-05-03 | 1965-11-02 | 1966-05-04 | $7700.00 | Window Closed / Lapsed |