Aluminum heat exchanger

Patent metadata

Field	Value
Publication number	US-2016014929-A1
Application number	US-201414771740-A
Country	US
Kind code	A1
Filing date	Feb 28, 2014
Priority date	Mar 1, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A heat transfer system is disclosed that includes a heat transfer fluid circulation loop, and also a heat exchanger that includes an aluminum alloy exterior surface having thereon a top surface coat derived from a composition comprising a trivalent chromium salt and an alkali metal hexafluorozirconate.

First claim

1 . A heat transfer system comprising a heat transfer fluid circulation loop, comprising a heat exchanger disposed in said heat transfer fluid circulation loop, the heat exchanger comprising an aluminum alloy exterior surface having thereon a top surface coat on at least a portion of the heat exchanger derived from a composition comprising a trivalent chromium salt and an alkali metal hexafluorozirconate in an aqueous solution.

2 . The heat transfer system of claim 1 , wherein the heat exchanger comprises a first aluminum alloy component connected by brazing to a second aluminum alloy component.

3 . The heat transfer system of claim 2 , wherein the top surface coat is disposed over the first aluminum alloy component, the second aluminum alloy component, and the brazing connecting the first and second aluminum alloy components.

4 . The heat transfer system of claim 2 , wherein the brazing comprises zinc.

5 . The heat transfer system of claim 2 , wherein the brazing includes residue of a brazing flux on the surface thereof, comprising a metal salt with a melting point of 564° C. to 577° C.

6 . The heat transfer system of claim 5 , wherein the metal salt comprises LiF and/or KAlF 4 .

7 . The heat transfer system of claims 1 , wherein said aluminum alloy exterior surface includes zinc enrichment of the aluminum alloy surface below said top surface coat.

8 . (canceled)

9 . (canceled)

10 . (canceled)

11 . The heat transfer system of claim 1 , wherein the entire surface of the heat exchanger is covered by said top surface coat.

12 . The heat transfer system of claim 1 , wherein the heat exchanger is a round tube plate fin heat exchanger, and only return bend tube portions of the round tube plate fin heat exchanger are covered by said top surface coat.

13 . A method of producing a heat transfer system, comprising:
contacting an aluminum alloy exterior surface of a heat exchanger with a composition comprising a trivalent chromium salt and an alkali metal hexafluorozirconate in an aqueous solution to form a top surface coat on the aluminum alloy surface; and assembling the heat exchanger comprising said top surface coat into a heat transfer fluid circulation loop.

14 . The method of claim 13 , wherein the heat exchanger comprises a first aluminum alloy component connected by brazing to a second aluminum alloy component.

15 . The method of claim 14 , wherein the top surface coat is disposed over the first aluminum alloy component, the second aluminum alloy component, and the brazing connecting the first and second aluminum alloy components.

16 . The method of claim 14 , wherein the brazing comprises zinc.

17 . The method of claim 14 , wherein the brazing includes residue of a brazing flux on the surface thereof, comprising a metal salt with a melting point of 564° C. to 577° C.

18 . The method of claim 17 , wherein the metal salt comprises LiF and/or KAlF 4 .

19 . The method of claim 13 , wherein said aluminum alloy exterior surface includes zinc enrichment of the aluminum alloy surface below said top surface coat.

20 . (canceled)

21 . (canceled)

22 . (canceled)

23 . The method of claim 13 , wherein said composition is applied by dip coating, spray coating, brush coating, or a combination comprising one or more of the foregoing.

24 . The method of claim 23 , wherein said composition is applied by dip coating.

25 . The method of claim 13 , wherein the entire surface of the heat exchanger is covered by said top surface coat.

26 . The heat transfer system of claim 13 , wherein the heat exchanger is a round tube plate fm heat exchanger, and only return bend tube portions of the round tube plate fin heat exchanger are covered by said top surface coat.

Assignees

• Carrier Corp

Inventors

• Jaworowski Mark R
• Lombardo Mary Teresa
• Taras Michael F
• Woldesemayat Mel
• Bealing Stephanie
• Patterson Matthew

Classifications

• C23C22/361

  containing titanium, zirconium or hafnium compounds · CPC title

• C23C2222/10

  Use of solutions containing trivalent chromium but free of hexavalent chromium · CPC title

• F28F19/06

  of metal · CPC title

• F28F21/084

  from aluminium or aluminium alloys · CPC title

• F28F19/02

  by using coatings, e.g. vitreous or enamel coatings · CPC title