Patent US3521458A successfully refreshed from Google Patents.
US3521458A
Expired / Lapsed
US
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Apparatus for making hydrogen slush using helium refrigerant
Assignee: Airco Inc
•
Filing: 1967-07-19
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Granted: 1970-07-21
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Expires: 1987-07-19
Abstract
No abstract record available.
Inventors
- 👤 Derk Th A Huibers
- 👤 Russell A Hemstreet
- 👤 Howard K Hover
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:07
CPC Classifications
F; F25; F25J; F25J1/00; F25J1/0002; F25J1/0005; F25J1/001; F25J1/003; F25J1/0047; F25J1/0052; F25J1/006; F25J1/0062; F25J1/0065; F25J1/02; F25J1/0203; F25J1/0204; F25J1/0243; F25J1/0257; F25J1/0275; F25J1/0276; F25J2205/00; F25J2205/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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US3108449A
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US3212283A
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US3256710A
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US3235002A
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US3354662A
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US3230737A
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US3319436A
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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) | 1973-07-20 | 1974-01-19 | 1974-07-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1977-07-20 | 1978-01-19 | 1978-07-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1981-07-20 | 1982-01-19 | 1982-07-21 | $7700.00 | Window Closed / Lapsed |