# US 2009/0260794 A1 · Heat Exchanger, Method for Manufacturing the Same, and Heat Exchanging Tube

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- Number: US 2009/0260794 A1
- Document ID: US20090260794A1
- Status: Published application
- Kind: A1
- Application number: 10/585,658
- Filed: 2005-01-07
- Published: 2009-10-22
- Earliest claimed: 2004-01-09
- Assignees: Showa Denko K.K.
- Inventors: Kazuhiko Minami; Tomoaki Yamanoi; Masahiro Kojima
- Web page: https://patentgrep.com/patent/US20090260794A1

## CPC

- B23K 1/0012: {Brazing of heat exchangers}
- F28D 1/05391: {with multiple rows of conduits or with multi-channel conduits combined with a particular flow pattern, e.g. multi-row multi-stage radiators}
- F28F 1/126: {consisting of zig-zag shaped fins (F28F1/105 takes precedence)}
- F28F 19/06: of metal
- B23K 2101/14: Heat exchangers
- Y10T 29/49378: Finned tube
- 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
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of 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

The present invention is directed to a method for manufacturing a heat exchanger in which a Zn thermally sprayed layer is formed on a surface of an aluminum flat tube 2 and then the Zn thermally sprayed tube is combined with an aluminum corrugated fin and brazed to the fin. The Zn thermally sprayed tube 2 is subjected to a Zn diffusion treatment by heating the tube before the brazing to diffuse the Zn in the tube surface, and thereafter the brazing is performed. The heat exchanger manufactured in this way can assuredly have a stable sacrifice corrosion layer and is excellent in corrosion resistance. The heat exchanger can be manufactured efficiently without major facility changes at low cost.

## Claims

### Claim 1

A method of manufacturing an aluminum heat exchanger in which a Zn thermally sprayed layer is formed on a surface of an aluminum flat tube and then the Zn thermally sprayed tube is combined with an aluminum corrugated fin and brazed to the fin,
wherein the Zn thermally sprayed tube is subjected to a Zn diffusion treatment by heating the tube before the brazing to diffuse the Zn in the tube surface, and thereafter the brazing is performed.

### Claim 2 (depends on 1)

The method of manufacturing an aluminum heat exchanger as recited in claim 1, wherein an adhered amount of the Zn on the surface of the flat tube is controlled so as to fall within a range of 6 to 12 g/m2.

### Claim 3 (depends on 1)

The method of manufacturing an aluminum heat exchanger as recited in claim 1, wherein an area rate of an area covered with the Zn on the surface of the flat tube is set to 50% or more of the surface of the Zn thermally sprayed tube.

### Claim 4 (depends on 1)

The method of manufacturing an aluminum heat exchanger as recited in claim 1, wherein the Zn diffusion treatment is performed by a heat-treatment of 470 to 620° C.×5 minutes to 10 hours in an inert gas atmosphere.

### Claim 5 (depends on 4)

The method of manufacturing an aluminum heat exchanger as recited in claim 4, wherein the inert gas atmosphere is a nitrogen gas atmosphere.

### Claim 6

An aluminum heat exchanger in which a Zn thermally sprayed tube in which a Zn thermally sprayed layer is formed on a surface of an aluminum flat tube is combined with an aluminum corrugated fin and brazed to the fin,
wherein a surface Zn concentration of a flat tube surface portion located at an intermediate position between adjacent tube-fin connected portions is 0.5 to 2.5 mass %, and
wherein a maximum Zn concentration in an eutectic portion of a fillet of the tube-fin connected portion is 1.0 to 3.5 mass %.

### Claim 7

A tube for use in aluminum num heat exchangers,
wherein a Zn diffusion treatment by heating a Zn thermally sprayed tube is executed after forming the Zn thermally sprayed layer on a surface of an aluminum flat tube.

### Claim 8 (depends on 7)

The tube for use in aluminum num heat exchangers as recited in claim 7, wherein an adhered amount of Zn on a surface of the Zn thermally sprayed tube is set to 6 to 12 g/m2.

### Claim 9 (depends on 8)

The tube for use in aluminum num heat exchangers as recited in claim 8, wherein an area ratio of an area covered with the Zn on the surface of the Zn Thermally Sprayed Tube is set to 50% or more of the surface of the Zn thermally sprayed tube.