US3558756A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of making gelatin wool filter
Assignee: McDonnell Douglas Corp
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Filing: 1969-03-04
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Granted: 1971-01-26
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Expires: 1989-03-04
Abstract
Abstract A GELATIN WOOL FILTER COMPRISING GELATIN FIBERS NATURALLY ARRANGED IN A FILTER PAD FOR FILTERING UP TO ABOUT 99% OF PARTICLES OF 0.3 MICRON AND LARGER, SAID FILTER BEING SOLUBLE IN WATER. THE PROCESS INCLUDES THE STEPS OF DISSOLVING GELATIN IN WATER, ADDING TO ALCHOL, DRYING, FORMING INTO A FILTER AND GAS STERILIZING.
Inventors
- 👤 Clifton Aldridge Jr
- 👤 Robert D Howell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 05:17
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/02; B01D39/04
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |