Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchanger

Abstract

Suppose each of the refrigerant tubes 53 of a heat exchanger has a potential A at a surface layer portion 53 a of an outer periphery thereof and a potential B at a core 53 b of the tube 53 other than the surface layer portion 53 a thereof, each of the fins 54 has a potential C, and a fillet 59 formed at the brazed portion between the tube 53 and the fin 54 has a potential D. These potentials then have the relationship of A ?C ?D<B. The potential A of the surface layer portion 53 a of the outer periphery of the refrigerant tube 53 is -850 to -800 mV, the potential B of the core 53 b of the tube 53 is -710 to -670 mV, the potential C of the fin 54 is -850 to -800 mV, and the potential D of the fillet 59 is -850 to -800 mV.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is an application filed under 35 U.S.C. §111(a) claiming the benefit pursuant to 35 U.S.C. §119(e) (1) of the filing data of Provisional Application No. 60 / 428,923 filed Nov. 26, 2002 pursuant to 35 U.S.C. §111(b).TECHNICAL FIELD [0002] The present invention relates to heat exchanges, such as condensers or evaporators for motor vehicle air conditioners for use with a chlorofluorocarbon refrigerant, gas coolers or evaporators for motor vehicle air conditioners for use with a CO2 refrigerant, motor vehicle oil coolers and motor vehicle radiators, heat exchanger tube members, heat exchanger fin members and a process for fabricating the heat exchanger. [0003] The term “potential” as used herein and in the appended claims refers to a potential as measured in a 5 wt. % NaCl aqueous solution having a pH of 3 using a saturated calomel electrode. Of course an atomic symbol representing a metal does not include alloys thereof. BA...

AI Technical Summary

Benefits of technology

The present invention provides a heat exchanger with improved heat exchange performance over a long period of time. The heat exchanger has heat exchange tubes and fins brazed together, with a fillet formed at the brazed portion between the heat exchange tube and the fin. The potentials of the heat exchanger are set up in a specific way, which ensures the heat exchange tubes, fins, and the fillet have the same potential. This prevents pitting and separation of the fin from the heat exchange tube. The heat exchanger has a long-lasting performance and is suitable for use in various applications.

Problems solved by technology

However, with the heat exchanger disclosed in the above publication, the fillet which undergoes sacrificial corrosion permits the fin to separate from the heat exchange tube, consequently entailing the problem of impairing heat transfer between the tube and the fin to lower the heat exchange efficiency.

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