| Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchanger -> Monitor Keywords |
|
|
  Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchangerUSPTO Application #: 20060086486Title: 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 53a of an outer periphery thereof and a potential B at a core 53b of the tube 53 other than the surface layer portion 53a 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 53a of the outer periphery of the refrigerant tube 53 is −850 to −800 mV, the potential B of the core 53b 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. (end of abstract)
Agent: Oblon, Spivak, Mcclelland, Maier & Neustadt, P.C. - Alexandria, VA, US Inventor: Takashi Sudo USPTO Applicaton #: 20060086486 - Class: 165143000 (USPTO) Related Patent Categories: Heat Exchange, Plural Casing-conduit Units, Line Or Common Header Connected The Patent Description & Claims data below is from USPTO Patent Application 20060086486. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is an application filed under 35 U.S.C. .sctn.111(a) claiming the benefit pursuant to 35 U.S.C. .sctn.119(e) (1) of the filing data of Provisional Application No. 60/428,923 filed Nov. 26, 2002 pursuant to 35 U.S.C. .sctn.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 CO.sub.2 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. BACKGROUND ART [0004] Known motor vehicle air conditioners, for example, for use with a chlorofluorocarbon refrigerant comprise a pair of headers arranged in parallel as spaced apart from each other, parallel flat heat exchange tubes joined at their opposite ends to the headers, and a corrugated fin disposed in an air passage clearances between each pair of adjacent heat exchange tubes and brazed to the pair of heat exchange tubes. The condenser is fabricated by preparing header members of aluminum or an aluminum alloy (hereinafter referred to as "aluminum" which includes both aluminum and aluminum alloy), tube members of aluminum, and fin members of a brazing sheet comprising a core of aluminum and claddings of aluminum brazing filler covering respective opposite surfaces of the core, and simultaneously brazing the header members, tube members and fin members. [0005] With the condenser described above, there is a need to prevent pitting corrosion of the heat exchange tubes in order to preclude the leakage of the refrigerant from the tubes. [0006] To prevent heat exchange tubes from pitting, heat exchangers have already been proposed in which the fins and the fillets formed at the brazed portions between the heat exchange tubes and the fins are given a base potential, and the fillets, fins and heat exchange tubes are made gradually nobler in potential in this order (see the publication of JP-A No. 1998-81931). [0007] With this heat exchanger, the sacrificial corrosion effect of the fillets prevents the heat exchange tubes from pitting, further preventing corrosion of the fins. [0008] 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. [0009] An object of the present invention is to overcome the above problem and to provide a heat exchanger wherein the fins can be prevented from separating from the heat exchange tubes. DISCLOSURE OF THE INVENTION [0010] The present invention provides a heat exchanger which comprises heat exchange tubes and fins each brazed to the heat exchange tube and wherein assuming that each of the heat exchange tubes has a potential A at a surface layer portion of an outer periphery thereof and a potential B at a portion thereof other than the surface layer portion, that each of the fins has a potential C, and that a fillet formed at the brazed portion between the heat exchange tube and the fin has a potential D, these potentials have the relationship of A.ltoreq.C.ltoreq.D.ltoreq.B. [0011] The heat exchanger of the invention has the relationship of A.ltoreq.C.ltoreq.D.ltoreq.B in potential. This indicates the following. C is equal to or nobler than A in potential, D is equal to or nobler than C in potential, and B is nobler than D in potential. With the heat exchanger of the present invention, the term "the surface layer portion of the outer periphery of the heat exchange tube" refers, for example, to the portion of the tube from the outermost surface to a depth of 0.15 mm. [0012] With the heat exchanger of the present invention, the heat exchange tubes can of course be prevented from pitting, and the separation of the fin from the heat exchange tube can be suppressed. This permits the heat exchanger to maintain its heat exchange performance over a prolonged period of time. [0013] The heat exchanger of the present invention may have the following potentials. The potential A of the surface layer portion of the outer periphery of the heat exchange tube: -850 to -800 mV, the potential B of the heat exchange tube at the portion thereof other than the surface layer portion: -710 to -670 mV, the potential C of the fin: -850 to -800 mV, and the potential D of the fillet formed at the brazed portion between the heat exchange tube and the fin: -850 to -800 mV. [0014] With the heat exchanger of the present invention, the surface layer portion of the outer periphery of the heat exchange tube may be made from an Al alloy containing 0.3 to 0.6 mass % of Cu, 0.1 to 0.4 mass % of Mn and 1.0 to 7.0 mass % of Zn, and the balance Al and inevitable impurities; the portion of the heat exchange tube other than the surface layer portion thereof may be made from an Al alloy containing 0.3 to 0.6 mass % of Cu and 0.1 to 0.4 mass % of Mn, and the balance Al and inevitable impurities; the fin may be made from an Al alloy containing 0.9 to 2.8 mass % of Zn, 1.0 to 1.5 mass % of Mn and up to 0.15 mass % of Cu, and the balance Al and inevitable impurities; and the fillet formed at the brazed portion between the heat exchange tube and the fin may be made from an Al alloy containing 0.1 to 0.4 mass % of Cu, 0.05 to 0.3 mass % of Mn and up to 5 mass % of Zn, and the balance Al and inevitable impurities. The Zn content mentioned of the fillet includes 0 mass %. Since the heat exchange tube is brazed to the fin with a brazing material containing Si, the fillet formed at the brazed portion between the heat exchange tube and the fin of course contains Si. This Si produces no influence on the heat exchanger of the invention, and no reference is therefore herein made to the Si content. Incidentally, the Si content of the fillet is usually about 3.0 to about 13.0 mass %. [0015] Preferably, the surface layer portion of the outer periphery of the heat exchange tube is made from an Al alloy containing 0.3 to 0.5 mass % of Cu, 0.1 to 0.3 mass % of Mn and 2.0 to 3.0 mass % of Zn, and the balance Al and inevitable impurities. [0016] Preferably, the portion of the heat exchange tube other than the surface layer portion thereof is made from an Al alloy containing 0.3 to 0.5 mass % of Cu and 0.1 to 0.3 mass % of Mn, and the balance Al and inevitable impurities. [0017] Preferably, the fin is made from an Al ally containing 2.0 to 2.5 mass % of Zn, 1.1 to 1.3 mass % of Mn and up to 0.1 mass % of Cu, and the balance Al and inevitable impurities. The Cu content mentioned of the fin includes 0 mass %. [0018] Preferably, the fillet formed at the brazed portion between the heat exchange tube and the fin is made from an Al alloy containing 0.2 to 0.3 mass % of Cu, 0.1 to 0.2 mass % of Mn and up to 3 mass % of Zn, and the balance Al and inevitable impurities. The Zn content mentioned of the fillet includes 0 mass %. [0019] The present invention provides a heat exchanger tube member for use in producing a heat exchanger comprising heat exchange tubes and fins each brazed to the heat exchange tube, the tube member comprising a tube member main body made from an Al alloy containing 0.3 to 0.6 mass % of Cu and 0.1 to 0.4 mass % of Mn, and the balance Al and inevitable impurities, and 2 to 8 g/m.sup.2 of a Zn spray layer formed over the entire outer peripheral surface of the tube member main body. [0020] With the heat exchanger tube member of the present invention, the tube member main body is preferably made from an Al alloy containing 0.3 to 0.5 mass % of Cu and 0.1 to 0.3 mass % of Mn, and the balance Al and inevitable impurities. The Zn spray layer is formed preferably in an amount of 2 to 6 g/m.sup.2. Continue reading... Full patent description for Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchanger Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchanger patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchanger or other areas of interest. ### Previous Patent Application: Temperature control of heat-generating devices Next Patent Application: Thermal management of systems having localized regions of elevated heat flux Industry Class: Heat exchange ### FreshPatents.com Support Thank you for viewing the Heat exchanger, heat exchanger tube member, heat exchanger fin member and process for fabricating the heat exchanger patent info. IP-related news and info Results in 2.25209 seconds Other interesting Feshpatents.com categories: Electronics: Semiconductor , Audio , Illumination , Connectors , Crypto , |
||
