US3559437A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for making heat transfer tubing
Assignee: Bank of Nova Scotia
•
Filing: 1968-11-04
•
Granted: 1971-02-02
•
Expires: 1988-11-04
Abstract
Abstract METHOD AND APPARATUS FOR MAKING HEAT TRANSFER TUBING CHARACTERIZED BY THE USE OF EXTERNAL ROLL MEANS OPERATING AGAINST AN INTERNAL MANDREL TO PRODUCE A PLURALITY OF EXTERNAL HELICAL GROOVES AND FINS OR RIBS IN CONJUNCTION WITH ADDITIONAL ROLL MEANS OPERATING BEYOND THE END OF THE INTERNAL MANDREL TO DEEPEN AN EXTERNAL GROOVE AND TO PRODUCE AN INTERNAL HELICALLY EXTENDING RIB.
Inventors
- 👤 James G Withers Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:17
CPC Classifications
B; B21; B21C; B21C37/00; B21C37/06; B21C37/15; B21C37/20; B21C37/207; B21D; B21D15/00; B21D15/04; F; F28; F28B; F28B1/00; F28B1/02; F28F; F28F1/00; F28F1/10; F28F1/12; F28F1/34; F28F1/36; F28F1/42; F28F1/422; F28F13/00; F28F13/06; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49377; Y10T29/49378; Y10T29/49382
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1974-02-01 | 1974-08-03 | 1975-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-01 | 1978-08-03 | 1979-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-01 | 1982-08-03 | 1983-02-02 | $7700.00 | Window Closed / Lapsed |