# US 11,305,329 B2 · Tubing with hydrophobic surface > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,329 B2 - Document ID: US11305329B2 - Status: Granted - Kind: B2 - Application number: 16/684,383 - Filed: 2019-11-14 - Published: 2020-05-14 - Granted: 2022-04-19 - Earliest claimed: 2018-11-14 - Assignees: Plymouth Tube Co. - Applicants: Plymouth Tube Co. - Inventors: Daniel S. Janikowski; Charles Murphy; Christian Lange - Web page: https://patentgrep.com/patent/US11305329B2 ## CPC - B21C 37/0818: {Manufacture of tubes by drawing of strip material through dies} - B21D 53/06: of metal tubes - B21H 8/005: {Embossing sheets or rolls} - F28F 1/00: Tubular elements; Assemblies of tubular elements (specially adapted for movement F28F5/00) - F28F 13/185: {Heat-exchange surfaces provided with microstructures or with porous coatings} - F28F 21/083: {from stainless steel} - F28F 21/086: {from titanium or titanium alloys} - B21D 53/02: heat exchangers {or parts thereof}, e.g. radiators, condensers {fins, headers}(making finned or ribbed tubes by fixing strip material or the like to tubes B21C37/22) - F28F 2245/04: hydrophobic - 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 - B21D: WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL (working or processing of wire B21F) - B21H: MAKING PARTICULAR METAL OBJECTS BY ROLLING, e.g. SCREWS, WHEELS, RINGS, BARRELS, BALLS (essentially from sheet metal B21D) - F28F: DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16) ## Abstract A method of forming a heat exchanger tube, particularly suited for condensing applications, contemplates cold-rolling a metallic strip to emboss a hydrophobic surface texture, to thereby form an embossed surface on the metallic strip. The method includes roll forming the metallic strip to a tubular shape, with the embossed surface on the exterior of the tubular shape, and welding the edges of the roll-formed strip to form a heat exchanger tube. Cold-rolling to emboss a hydrophobic surface texture exhibiting a contact angle of at least about 75° is contemplated, with processing including heat-treatment to minimize degradation of the hydrophobic surface texture, and roll-forming to avoid deformation of the hydrophobic surface texture, ## Claims ### Claim 1 A method of making a heat-exchanger tube, comprising the steps of: providing a metallic strip; cold-rolling the metallic strip to emboss a hydrophobic surface texture to form an embossed surface of the metallic strip; roll-forming said metallic strip to a tubular shape, with said embossed surface of said metallic strip positioned on the exterior of the tubular shape; and welding the edges of the roll-formed strip to form a heat-exchanger tube. ### Claim 2 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, wherein said cold-rolling step embosses said hydrophobic surface texture to exhibit a contact angle of at least about 75 degrees. ### Claim 3 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, wherein said cold-rolling step embosses said hydrophobic surface texture to exhibit a contact angle of at least about 90 degrees. ### Claim 4 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, including heat-treating said heat-exchanger tube to minimize degradation of said hydrophobic surface texture. ### Claim 5 (depends on 4) The method of making a heat-exchanger tube in accordance with claim 4, wherein said heat-treating step includes a specialized heat-treatment, including a method to minimize deformation of said hydrophobic surface texture. ### Claim 6 (depends on 4) The method of making a heat-exchanger tube in accordance with claim 4, wherein said heat-treating step comprises hydrogen annealing. ### Claim 7 (depends on 4) The method of making a heat-exchanger tube in accordance with claim 4, wherein said heat-treating step includes providing a gas blend that includes hydrogen. ### Claim 8 (depends on 4) The method of making a heat-exchanger tube in accordance with claim 4, wherein said heat-treating step includes providing an inert gas that minimizes oxidation of said hydrophobic surface texture. ### Claim 9 (depends on 4) The method of making a heat-exchanger tube in accordance with claim 4, wherein said heat-treating step includes employing a specialized quick quench system. ### Claim 10 (depends on 9) The method of making a heat-exchanger tube in accordance with claim 9, wherein said quick quench system employs forced gas flow. ### Claim 11 (depends on 9) The method of making a heat-exchanger tube in accordance with claim 9, wherein said quick quench system comprises a relatively soft, conductive shoe for removal of heat. ### Claim 12 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, wherein said metallic strip comprises stainless steel. ### Claim 13 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, wherein said metallic strip comprises one of titanium and titanium alloy. ### Claim 14 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, wherein said roll-forming step includes providing forming rolls having sufficiently soft surfaces to form said tubular shape without significant deformation of said hydrophobic surface texture. ### Claim 15 (depends on 14) The method of making a heat-exchanger tube in accordance with claim 14, wherein said forming rolls entirely comprise soft material, or have a sufficiently soft surface layer. ### Claim 16 (depends on 1) The method of making a heat-exchanger tube in accordance with claim 1, wherein said roll-forming step includes applying lubricant to forming rollers to reduce friction and marring of the embossed surface of the heat-exchanger tube. ### Claim 17 (depends on 16) The method of making a heat-exchanger tube in accordance with claim 16, wherein said step of applying lubricant includes applying atomized lubricant to said forming rollers. ### Claim 18 (depends on 17) The method of making a heat-exchanger tube in accordance with claim 17, including applying said lubricant to said forming rollers at a distance of about 6 inches from forming surfaces of said forming rollers.