Patent US3330337A successfully refreshed from Google Patents.
US3330337A
Expired / Lapsed
US
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Vented duplex heat exchanger tubes
Assignee: Standard Oil Co
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Filing: 1964-12-24
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Granted: 1967-07-11
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Expires: 1984-12-24
Abstract
No abstract record available.
Inventors
- 👤 Cecil B Heith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:38
CPC Classifications
F; F28; F28F; F28F21/00; F28F21/08; F28F21/081; F28F21/082; F28F9/00; F28F9/02; F28F9/04; F28F9/16; F28F9/165; F28F9/167; F28F2255/00; F28F2255/18
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
45 words
IN A HEAT EXCHANGER, A TUBE SHEET, SAID TUBE SHEET HAVING A ROLLED DUPLEX TUBE EXTENDING THERETHROUGH AND TERMINATING IN AN END, SAID DUPLEX TUBE INCLUDING AN INNER TUBULAR PORTION AND AN OUTER TUBULAR PORTION, SAID EXTENDING END HAVING A GAS-PERMEABLE METAL SLEEVE OVER SAID
Claim 2
Dependent Claim
45 words
IN A HEAT EXCHANGER, A TUBE SHEET, SAID TUBE SHEET HAVING A ROLLED DUPLEX TUBE EXTENDING THERETHROUGH AND TERMINATING IN AN END, SAID DUPLEX TUBE INCLUDING AN INNER TUBULAR PORTION AND AN OUTER TUBULAR PORTION, SAID EXTENDING END HAVING A GAS-PERMEABLE METAL SLEEVE OVER SAID
References Cited (Backward Citations)
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US1714703A
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GB432230A
Cited
US2157596A
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US2394402A
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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) | 1970-07-10 | 1971-01-09 | 1971-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-07-10 | 1975-01-09 | 1975-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-07-10 | 1979-01-09 | 1979-07-11 | $7700.00 | Window Closed / Lapsed |