Patent Publication Number: US-6666264-B2

Title: Heat exchanger

Description:
FIELD OF THE INVENTION 
     The present invention provides a heat exchanger and, more particularly, a heat exchanger having a tank formed from two single sheets of aluminum. 
     BACKGROUND OF THE INVENTION 
     Presently, most heat exchanger units for use in motor vehicles (e.g., radiators and charge air coolers) are made by mounting aluminum tubes and fins between two tanks (also sometimes referred to in the art as manifolds) that act as reservoirs for the liquid to be cooled. In charged air cooler applications, the heat exchanger comprises a cast aluminum tank that is welded to an aluminum header. In radiator applications, the tank usually consists of an aluminum header and a plastic tank. A plurality of tubes are connected to the aluminum header, which is then crimped to the plastic tank using a rubber O-ring as a sealing element to create a leak-proof vessel. The plastic tank is typically molded so as to provide mounting points for attachment of the heat exchanger to the motor vehicle and also to provide mounting points for accessories that are mounted to the heat exchanger. 
     One of the problems associated with heat exchangers of the type described in the previous paragraph is that fluid can leak from the tank at the O-ring joint. Furthermore, the plastic tank tends to warp during and after processing, which can also lead to additional leaking and assembly problems. Moreover, recycling of this type of heat exchanger is problematic because the plastic tank must be mechanically separated from the remaining parts of the heat exchanger. 
     SUMMARY OF THE INVENTION 
     The present invention provides a heat exchanger comprising a tank, a plurality of tubes in fluid communication with the tank, and a plurality of fins extending between the tubes. The tank consists essentially of a header member and a cover member, each of which is formed from a single sheet of aluminum. The header member includes an elongate generally planar base section having first and second ends and a middle portion disposed between the first and second ends. The header member also includes a flange section that extends along one edge of the base section and a wall section that extends along the opposite edge of the base section. The cover member has a central section that is spaced apart from the middle portion of the header member and a periphery that is joined to the first and second ends of the base section, the flange section, and the wall section. The cover member is preferably joined to the header member by brazing. The heat exchanger can accommodate mounts for mounting the heat exchanger to motor vehicle or for mounting various accessories to the heat exchanger at virtually any location adjacent to the joint between the cover member and the header member. 
     A heat exchanger according to the present invention preferably comprises an all-aluminum structure, meaning that the plurality of tubes, plurality of fins, and tank are all constructed of aluminum. Thus, the heat exchanger requires no disassembly in order to facilitate recycling. Furthermore, a heat exchanger according to the present invention does not rely on rubber O-rings to insure a seal between the tank and header. Therefore, a heat exchanger according to the present invention is less prone to leakage from fatigue or heat stresses. 
     The foregoing and other features of the invention are hereinafter more fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the present invention may be employed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a preferred embodiment of a heat exchanger according the present invention. 
     FIG. 2 is a perspective view of a header member of the heat exchanger shown in FIG.  1 . 
     FIG. 3 is a perspective view of a cover member of the heat exchanger shown in FIG.  1 . 
     FIG. 4 is a perspective view of the header member and cover member shown in FIGS. 2 and 3, respectively, in the process of being brought together to be joined. 
     FIG. 5 is a perspective view of the header member and cover member shown in FIG. 4 after they have been joined. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A heat exchanger according to the present invention comprises a tank, a plurality of tubes in fluid communication with the tank, and a plurality of fins extending between the tubes. The tubes and fins are preferably formed of aluminum. 
     With reference to FIG. 1, which shows a perspective view of a preferred embodiment of a heat exchanger according to the invention, a heat exchanger  10  comprises a first tank  20   a  and a second tank  20   b,  a plurality of tubes  30  in fluid communication with the first tank  20   a  and the second tank  20   b,  and a plurality of fins  40  extending between the tubes  30 . In the preferred embodiment, both the first tank  20   a  and second tank  20   b  are identical in configuration. However, it will be appreciated that heat exchangers can be formed using only one tank, or using two or more tanks having different configurations. 
     Fluid that needs to be cooled is pumped into the first tank  20   a  through an inlet port  50   a.  The fluid passes from the first tank  20   a  through the tubes  30  where the heat of the fluid is exchanged with cooling air passing over and around the tubes  30  and fins  40 . The cooled fluid then passes from the tubes  30  into the second tank  20   b  and then flows out of outlet port  50   b.  A heat exchanger of this type is sometimes referred to in the art as a one-path cross flow type heat exchanger or radiator, and is particularly useful in motor vehicle applications to cool engine coolant. 
     The tank of a heat exchanger according to the present invention consists essentially of a header member that is formed from a single sheet of aluminum and a cover member that is also formed from a single sheet of aluminum. In this respect, the tank can be described as a two-piece assembly. 
     FIG. 2 shows a perspective view of a header member  60  of one of the tanks  20   a  or  20   b  (they are identical) in the heat exchanger  10  shown in FIG.  1 . The header member  60  has an elongate generally planar base section  70 , a flange section  80  extending along an edge  90  of the base section  70 , and a wall section  100  extending along an opposite edge  110  of the base section  70 . The base section  70  has first and second ends  120   a  and  120   b,  respectively, and a middle portion  130  disposed between the first and said second ends  120   a,    120   b.  A plurality of openings  140  are provided in the middle portion  130  of the base section  70 . Each of the openings  140  is sized to receive one of the plurality of tubes  30 . 
     In the preferred embodiment of the invention illustrated in FIG. 2, the flange section  80  extends downwardly from the  90  edge of the base section  70  in a direction generally parallel with the tubes  30 , and the wall section  100  extends upwardly from the opposite edge  110  of the base section  70  in a direction generally away from the tubes  30 . However, it will be appreciated that the orientation of the flange section could be reversed provided that the periphery of the cover member was also modified to contact the flange section. 
     FIG. 3 shows a perspective view of a cover member  150  of one of the tanks  20   a  or  20   b  (they are identical) in the heat exchanger  10  shown in FIG.  1 . The cover member  150  has a central section  160  that is prefereably dome-shaped. The periphery  170  of the cover member  150  is arranged to make contact with the first and second ends  120   a,    120   b,  the flange section  80 , and the wall section  100  of the header member  60 . 
     FIG. 4 shows the cover member  150  and header member  60  in the process of being brought together to be joined to form a tank  20 . It should be noted that, as illustrated in FIG. 4, the first and second ends  120   a,    120   b  of said base section  70  of the header member  60  can extend beyond the point where the periphery  170  of the cover member contact the ends  120   a,    120   b,  to form mounting points  180  for attaching the heat exchanger  10  to a motor vehicle or other device and/or for mounting accessories. 
     It will be appreciated that the location of the mounting points  180  is not per se critical, and that the header member and cover member can be modified in various manners to allow for various mounting options in addition to the mounting options illustrated in FIG.  4 . In other words, the heat exchanger  10  can accommodate mounts for mounting the heat exchanger to motor vehicle or for mounting various accessories to the heat exchanger at virtually any location adjacent to the joint between the cover member and the header member. 
     FIG. 5 is a perspective view of the cover member  150  and header member  60  shown in FIG. 4 after they have been brought together and joined to form a tank  20 . As shown in FIG. 5, the central section  160  of the cover member  150  is spaced apart from the middle portion  130  of the header member  60 , but the periphery  170  of the cover member  150  is joined to the first and second ends  120   a,    120   b,  the flange section  80 , and the wall section  100  of the header member  60  to form a fluid-tight seal between the cover member  150  and the header member  60 . 
     The header member is preferably made as a stamping and is pierced (to form the openings), extruded (to form a collar for the inlet/outlet port), and then formed into shape (to form the flange section and the wall section). The cover member is preferably a drawn and trimmed stamping with a periphery formed to match the shape of the first and second ends, wall section, and flange section of the header member. The portion of the periphery of the cover member contacting the header member should be sufficient to allow for brazing, which is well known in the art. The cover member is preferably joined to the header member after assembly of the tubes and fins, which can be assembled using a conventional core building assembly. The cover member can is preferably secured to the header member prior to brazing using tabs, staking, or by clamping the two parts together in a brazing fixture. After the cover member is secured to the header member, the entire assembly is preferably placed in a brazing oven. 
     The heat exchanger according to the present invention is preferably formed of aluminum parts. As used throughout the instant description and in the appended claims, the term “aluminum” is not intended to be strictly construed as referring to pure aluminum, but should be understood to refer to pure aluminum and the various alloys of aluminum. In the most preferred embodiment of the invention, the tubes, fins, and tank(s) are all formed from aluminum, and thus can be recycled without the need for labor intensive disassembly. 
     The heat exchanger according to the present invention also eliminates the need for rubber O-rings, which are prone to leakage and weakening due to fatigue and heat stress. Heat exchangers according to the present invention are particularly useful as radiators for motor vehicles, but can also be used in other applications where it is necessary to cool fluids, or for air to air heat exchange. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details shown and described herein. Various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.