# US 5,348,213 A · Method for the manufacture of internally enhanced welded tubing

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- Number: US 5,348,213 A
- Document ID: US5348213A
- Status: Granted
- Kind: A
- Application number: 07/997,387
- Filed: 1992-12-28
- Granted: 1994-09-20
- Earliest claimed: 1992-12-28
- Assignees: Olin Corporation
- Inventors: Myron R. Randlett; Jerome M. Dupy
- Web page: https://patentgrep.com/patent/US5348213A

## CPC

- B21C 37/0822: {Guiding or aligning the edges of the bent sheet}
- B21C 37/0803: {the tubes having a special shape, e.g. polygonal tubes}
- B21C 37/083: Supply, or operations combined with supply, of strip material
- B21C 37/225: {longitudinally-ribbed tubes}
- B23K 11/34: Preliminary treatment
- B23K 13/025: {for tubes}
- B23K 33/006: {for cylindrical workpieces}
- B23K 37/06: for positioning the molten material, e.g. confining it to a desired area
- F16L 9/17: obtained by bending a sheet longitudinally and connecting the edges
- F28F 1/40: the means being only inside the tubular element
- F28F 1/42: the means being both outside and inside the tubular element
- Y10T 29/49391: Tube making or reforming
- B21C: MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- F16L: PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

There is provided a method for the manufacture of a welded tube having an enhanced inner wall. A fin insert shapes the edges of a metallic strip prior to welding and minimizes the formation of a weld bead inside the tube. The portion of the edge of the metallic strip adjacent the outer surface of the tube is formed to a first angle, while that portion of the edge adjacent an inner wall of the tube is formed to a second, lesser angle.

## Claims

### Claim 1

A method for the manufacture of a heat exchange tube formed from a metallic strip having opposing first and second surfaces and opposing longitudinal edges joined by a longitudinally running weld bead, comprising the steps of:
a) forming a pattern on said second surface of said metallic strip;
b) forming said metallic strip into an ellipse with said second surface forming an inner wall;
c) shaping, with a fin insert, the opposing longitudinal edges of said metallic strip to:
(i) a first angle adjacent said first surface,
(ii) a second angle adjacent said second surface, said first angle and said second angle being measured relative to a center line axis which runs perpendicular to said longitudinally running weld bead, and
(iii) an inflection zone connecting said first angle and said second angle wherein said inflection zone is closer to said center line axis than said shaped opposing longitudinally edges;
d) contacting said shaped opposing longitudinal edges of said metallic strip; and
e) welding said shaped opposing longitudinal edges together.

### Claim 2 (depends on 1)

The method of claim 1 wherein said first angle is from about 6.degree. to about 18.degree..

### Claim 3 (depends on 2)

The method of claim 2 wherein said first angle is from about 10.degree. to about 15.degree..

### Claim 4 (depends on 2)

The method of claim 2 wherein said second angle is from about 0.degree. to about 10.degree..

### Claim 5 (depends on 4)

The method of claim 4 wherein said second angle is about 0.degree..

### Claim 6 (depends on 2)

The method of claim 2 wherein said second angle is from about 0.degree. to about 10.degree..

### Claim 7 (depends on 6)

The method of claim 6 wherein said second angle is from about 1.degree. to about 5.degree..