US3881342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making integral finned tube for submerged boiling applications having special o.d. and/or i.d. enhancement
Assignee: Bank of Nova Scotia
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Filing: 1973-11-07
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Granted: 1975-05-06
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Expires: 1993-11-07
Abstract
Abstract Method for making heat transfer tubing comprising forming generally circumferentially extending adjacent fin convolutions provided with recesses in the outer edges thereof, and bending each fin convolution uniformly toward the adjacent convolution to partially enclose the spaces between adjacent convolutions so as to leave a continuous opening communicating with the interior of the spaces between the tip of each fin convolution and the side of the adjacent convolution, in which the opening has a plurality of spaced enlargements provided by the recesses in the outer edges of the fins. In a preferred embodiment the tubing is provided with internal ribbing in such a way as to automatically produce the recesses in the edges of the fin convolutions.
Inventors
- 👤 John K Thorne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:15
CPC Classifications
F; F28; F28F; F28F13/00; F28F13/18; F28F13/185; F28F13/187; B; B21; B21C; B21C37/00; B21C37/06; B21C37/15; B21C37/20; B21C37/207; F28F1/00; F28F1/10; F28F1/42; F28F1/422; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/4935; Y10T29/49377; Y10T29/49378; Y10T29/49382; Y10T29/49384
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
176 words
The method of making heat transfer tubing modified for the enhancement of heat transfer from heating fluid flowing through the tubing to liquid in contact with the exterior surface thereof in submerged boiling applications, which comprises providing a multiplicity of axially spaced fin convolutions extending radially outwardly from and around the tubing so as to provide fin convolutions having inner base portions extending generally radially outwardly from said wall and having outer portions terminating in an outer edge, providing a plurality of circumferentially spaced recesses extending inwardly from the outer edges of said convolutions, thereafter bending the fin convolutions laterally uniformly to bring the outer edge of each fin convolution into proximity to the side of the adjacent convolution to form partially enclosed spaces between each pair of adjacent convolutions having continuous circumferentially extending elongated restricted openings communicating with the interior of said spaces, the recesses in the edges of said fin convolutions forming substantial enlargements in said openings, said openings having an average substantially uniform width intermediate said enlargements of not more than 0.007 inch.
Claim 2
Independent Claim
176 words
The method of making heat transfer tubing modified for the enhancement of heat transfer from heating fluid flowing through the tubing to liquid in contact with the exterior surface thereof in submerged boiling applications, which comprises providing a multiplicity of axially spaced fin convolutions extending radially outwardly from and around the tubing so as to provide fin convolutions having inner base portions extending generally radially outwardly from said wall and having outer portions terminating in an outer edge, providing a plurality of circumferentially spaced recesses extending inwardly from the outer edges of said convolutions, thereafter bending the fin convolutions laterally uniformly to bring the outer edge of each fin convolution into proximity to the side of the adjacent convolution to form partially enclosed spaces between each pair of adjacent convolutions having continuous circumferentially extending elongated restricted openings communicating with the interior of said spaces, the recesses in the edges of said fin convolutions forming substantial enlargements in said openings, said openings having an average substantially uniform width intermediate said enlargements of not more than 0.007 inch.
Claim 3
Dependent Claim
43 words
The method as defined in claim 1 in which said recesses are dimensioned to define with the side of the adjacent convolution an opening enlargement whose width is at least 50 percent greater than the average width of the openings intermediate said enlargements.
Claim 4
Dependent Claim
25 words
The method as defined in claim 1 in which the elongated restricted openings intermediate said enlargements have an average width of 0.001 - 0.005 inch.
Claim 5
Dependent Claim
125 words
The method as defined in claim 1 which comprises the step of forming the fins and the recesses in the fins by rolling the fins from the material of the tube by finning rolls applied to the outside of the tube under radial pressure to reduce the initial diameter of the tube to conform internally to a helically grooved mandrel to form internal helical ribs in the tube, the mandrel grooves having a substantially longer lead than the lead of the fins whereby each rib crosses a multiplicity of fins and produces a recess in the outer edge of the fin at the crossing of each fin with each mandrel groove as a result of displacement of tube material into the groove of the mandrel.
Claim 6
Dependent Claim
22 words
The method as defined in claim 1 which comprises bending the fins as aforesaid by drawing the finned tube through a die.
Claim 7
Dependent Claim
22 words
The method as defined in claim 4 which comprises bending the fins as aforesaid by drawing the finned tube through a die.
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) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |