Patent Abstract:
Various embodiments of the present invention provide a heat exchanger having a collection tank having an internal chamber, and a header connected to the collection tank and receiving a number of flat tubes through apertures in the header. In some embodiments, a reinforcing member received within the collection tank and/or the header functions to reinforce the header and/or the collection tank in applications where these elements are subject to internal pressures that would otherwise deform the header and/or collection tank to an unacceptable extent. Also, some heat exchanger embodiments utilized a curved gasket on each flat tube to match the shape of the flat tubes and a curved header. Also, another gasket can be located between a metal or plastic collection tank and a plastic or metal header, respectively, to prevent leakage therebetween.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of Provisional Application Ser. No. 61/001,438, filed Nov. 1, 2007, the entire content of which is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    A variety of heat exchangers exist in which a number of tubes are connected to and in fluid communication with a collection tank for introducing and/or removing fluid from the flat tubes. In many cases, the applications of such heat exchangers result in high pressure and thermal stresses, such as in locations at and adjacent to the connections of the flat tubes to the collection tank. Also, it is desirable for such collection tanks and the connections of the flat tubes thereto to withstand significant pressure without excessive deformation or damage—despite the desire to construct collection tanks from increasingly thinner and lighter materials. Particularly in cases in which the collection tanks are constructed of multiple parts (e.g., a header plate and a structure defining the remainder of the collection tank), this capability should extend to the interface between the collection tank parts. 
         [0003]    Further design issues for many heat exchangers relate to the use of gaskets between heat exchanger components, such as tube-to-header plate gaskets, gaskets located between header plates and other collection tank components, and the like. Such gaskets must perform their hydraulic or pneumatic sealing functions while being exposed in some applications to high pressures and/or temperatures, material expansion and contraction, and other challenges. Reliable gaskets and gasket retention continue to be elusive in many applications. 
         [0004]    Accordingly, it will be appreciated that heat exchangers having collection tanks and collection tank-to-flat tube joints adapted to withstand thermal and/or pressure stresses and cycling are welcome additions to the industry, as are reliable heat exchanger gaskets and gasket retention designs, and heat exchangers that are relatively light weight and that can be produced more efficiently and at a lower cost. 
       SUMMARY 
       [0005]    Some embodiments of the present invention provide a header for a collection tank of a heat exchanger. The header can provide an increased level of strength to the heat exchanger and to connections between the header and tubes connected thereto. The header can have a convex shape configured to reduce thermal mechanical stresses at tube-to-header joints, and to reduce pressure stresses. 
         [0006]    In some embodiments, the header of the collection tank is manufactured from plastic, and is curved about a longitudinal axis of the collection tank, thereby presenting a generally convex shape toward the tubes connected thereto, and a generally concave shape toward an interior of the collection tank. The tubes can have any cross-section shape desired. However, unique advantages can be achieved by the use of flat tubes (i.e., tubes having opposing substantially broad flat sides joined by opposing narrow sides) connected to the header. 
         [0007]    By virtue of a curved header as described above, plastic headers can withstand internal collection tank pressures that could otherwise generate significant header deformation. Under pressure loading of the curved plastic header described above, there is a considerably reduced degree of header deformation. In some embodiments, such deformation can even be eliminated. As a result, the mechanical load experienced by connections between the header and tubes fastened thereto is considerably reduced. 
         [0008]    Additionally, by virtue of the curved plastic header as described above, it is possible in some embodiments to achieve increased strength of the header and of the connections between the header and tubes. Since the strength of the header and the tube-to-header connections often decreases from the periphery of the header toward the center of the header, the above-described header curvature in a central region of the header significantly increases the strength of the header in the central region. As a result of the increased strength, it is possible to achieve weight and cost savings by reduction of the thickness of the material from which the header and/or tubes is constructed. The increased mechanical strength also increases the service life of a collection tank and heat exchanger having such a header. Such advantages do not necessarily require any additional expenditure with regard to the header and collection tank material, the number of header and collection tank components, and the individual production stages of the header and collection tank. Also, reproducible and permanently sealed connections between the header and individual tubes are possible using the curved header described above and relatively low production tolerances. 
         [0009]    Other aspects of the present invention relate to manners in which a header can be connected to the rest of a collection tank while retaining a gasket or other seal in position with respect to such parts, manners in which to provide a seal at the interfaces between the tubes and header of a heat exchanger, and manners in which the collection tank and portions of the collection tank and header interface can be reinforced to increase the pressure capacity of the collection tank and/or to enable the use of thinner and different collection tank materials. 
         [0010]    In some embodiments, a heat exchanger is provided, and comprises a plurality of tubes each having opposing broad and substantially flat sides joined by two opposing narrow sides; a header having a plurality of apertures each dimensioned to receive a corresponding tube of the plurality of tubes; a collection tank coupled to the header and having an internal chamber in fluid communication with the plurality of tubes; a gasket located between the collection tank and the header; and at least one reinforcement extending across the internal chamber. 
         [0011]    Some embodiments of the present invention provide a heat exchanger, comprising a plurality of tubes each having opposing broad and substantially flat sides joined by two opposing narrow sides; a plastic collection tank having an internal chamber in fluid communication with the plurality of tubes; a metal header coupled to the plastic collection tank and having a plurality of apertures each dimensioned to receive a corresponding tube of the plurality of tubes, the metal header elongated in a longitudinal direction and curved about a longitudinal axis of the metal header to present a concave shape to the internal chamber and a convex shape away from the internal chamber; a gasket at least partially separating the metal header from the plastic collection tank and sealing a gap between the metal header and the plastic collection tank; and a reinforcement extending across the internal chamber and at least partially retaining the gasket in position between the metal header and the plastic collection tank. 
         [0012]    In some embodiments, a heat exchanger is provided, and comprises a plurality of tubes each having opposing broad and substantially flat sides joined by two opposing narrow sides; a collection tank having an internal chamber in fluid communication with the plurality of tubes; a header coupled to the collection tank and having a plurality of apertures each dimensioned to receive a corresponding tube of the plurality of tubes, the header elongated in a longitudinal direction and curved about a longitudinal axis of the header to present a concave shape to the internal chamber and a convex shape away from the internal chamber; and a gasket received on a tube of the plurality of tubes and curved about the longitudinal axis of the header. 
         [0013]    Still other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a perspective view of a collection tank having a tank reinforcement member according to an embodiment of the present invention. 
           [0015]      FIG. 2  is an exploded view of the collection tank shown in  FIG. 1 . 
           [0016]      FIG. 3  is a detail view of the tank reinforcement member shown in  FIGS. 1 and 2 . 
           [0017]      FIG. 4  is a detail view of the gasket shown in  FIGS. 2 and 3 . 
           [0018]      FIG. 5A  is a cross-sectional view of the collection tank shown in  FIG. 1 , taken along line  5 A- 5 A of  FIG. 1 . 
           [0019]      FIG. 5B  is a perspective assembled view of the collection tank and the tank reinforcement member shown in  FIGS. 1-3  and  5 A. 
           [0020]      FIG. 6A  is a schematic cross-sectional view of a collection tank, reinforcement member, and header according to an embodiment of the present invention. 
           [0021]      FIG. 6B  is a perspective view of a collection tank assembly according to an embodiment of the present invention. 
           [0022]      FIG. 6C  is an exploded perspective view of the collection tank assembly shown in  FIG. 6B . 
           [0023]      FIG. 6D  is a detail view of the collection tank assembly shown in  FIGS. 6B and 6C . 
           [0024]      FIG. 6E  is a perspective view of a part of the collection tank assembly shown in  FIGS. 6B-6D . 
           [0025]      FIG. 6F  is a cross-sectional perspective view of part of the collection tank assembly shown in  FIGS. 6B-6E . 
           [0026]      FIG. 6G  is a cross-sectional perspective view of part of a heat exchanger according to another embodiment of the present invention. 
           [0027]      FIG. 6H  is a cross-sectional perspective view of part of a heat exchanger according to another embodiment of the present invention. 
           [0028]      FIG. 6I  is a cross-sectional perspective view of part of a heat exchanger according to another embodiment of the present invention. 
           [0029]      FIG. 7  is a top perspective view of a header according to an embodiment of the present invention. 
           [0030]      FIG. 8  is a bottom perspective view of the header shown in  FIG. 7 . 
           [0031]      FIG. 9  is a perspective view of part of a heat exchanger according to another embodiment of the present invention. 
           [0032]      FIG. 10  is a cross-sectional perspective view of the heat exchanger shown in  FIG. 9 , taken along line  10 - 10  of  FIG. 9 . 
           [0033]      FIG. 11  is a cross-sectional perspective view of a heat exchanger according to another embodiment of the present invention. 
           [0034]      FIG. 12  is a perspective view of a grommet shown in  FIG. 9 . 
           [0035]      FIG. 13  is an end view of the grommet shown in  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0036]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
         [0037]      FIGS. 1-5B  illustrate a collection tank assembly header  110  adapted for a collection tank of a heat exchanger  124 . The heat exchanger  124  is suitable for any application in which heat exchange takes place with fluid passing through the collection tank. Such applications exist in vehicle systems, such as those used in conjunction with internal combustion engines. In some applications for example, the heat exchanger  124  can function as a cooler, as a condenser, or as an evaporator. Also, in some applications, the heat exchanger  124  can be connected to exchange heat in a refrigerant circuit. 
         [0038]    The collection tank assembly  110  illustrated in  FIGS. 1-5B  includes a collection tank  100  (only part of which is shown in  FIGS. 1-5B ), a tank reinforcement member  104 , and a gasket  108 . The illustrated collection tank  100  is constructed of a first portion  100 A at least partially defining an enclosure through which fluid flows, and another portion (not shown in  FIGS. 1-5B ) called a header. The header connects with the first portion  100 A of the collection tank  100  to substantially enclose an internal chamber of the collection tank  100 . An example of a header  204  that can be used in conjunction with the first collection tank portion  100 A is shown in  FIGS. 7 and 8 , and will be described in greater detail below. 
         [0039]    In some embodiments, the first portion  100 A of the collection tank  100  is made of aluminum, steel, iron, or other metal, whereas the header (e.g., header  104 ) is made of plastic. Although this material combination provides unique performance results (including a thin-walled but strong first portion  100 A able to withstand significant pressures while permitting the use of a less expensive and/or easy to manufacture plastic header), other materials and material combinations are possible. For example, in other embodiments, both the first portion  100 A and the header are made of plastic. As another example, in other embodiments, both the first portion  100 A and the header are made of metal. Alternatively, in still other embodiments, the first portion  100 A is made of plastic, while the header is made of metal. 
         [0040]    The first portion  100 A of the collection tank  100  can be secured to the header (e.g., header  204  shown in  FIGS. 7 and 8 ) in a number of different manners, some of which provide a degree of resistance to fluid leakage under internal collection tank pressures. To this end, peripheral edges of the first portion  100 A can abut peripheral edges of the header, such as the planar peripheral edges of the header  204  shown in  FIGS. 7 and 8 . The first portion  100 A and the header can be secured in these and other locations by welding, soldering, brazing, and the like. 
         [0041]    To prevent leakage of fluid out of the collection tank  100 , a gasket  108  is located between the first portion  100 A of the collection tank  100  and the header. The illustrated gasket  108  extends about the periphery of the first portion  100 A and the header, and can be made of rubber, plastic, or any other material suitable for forming a seal. 
         [0042]    As mentioned above, the collection tank assembly  110  shown in  FIG. 105B  also includes a tank reinforcement member  104  to help retain the gasket  108  in a position with respect to the first portion  100 A of the collection tank  100  and the header in which fluid is prevented from exiting the collection tank  100  during operation of the heat exchanger  124 . The reinforcement member  104  shown in  FIG. 7  is plastic, and can be manufactured by injection molding. Alternatively, the reinforcement member can be made of any other suitable material (including without limitation aluminum, steel, iron, and other metals, composite materials, and the like), and can be manufactured in any other suitable manner (including without limitation casting, stamping, pressing, deep drawing, extruding, machining, and the like). 
         [0043]    The tank reinforcement member  104  illustrated in  FIGS. 1-3 ,  5 A, and  5 B includes interlock apertures  112  configured to receive the gasket  108 . The apertures  112  can be dimensioned to receive and retain portions of the gasket  108  by an interference fit. The illustrated tank reinforcement member  104  further includes cross-webs  116 , which provide further support to the tank reinforcement member  104 . The cross-webs  116  enable the collection tank assembly  110  to withstand greater internal pressures, and can enable the collection tank assembly  110  to withstand loads experienced by a header being crimped to the collection tank  100 . 
         [0044]    The illustrated gasket  108  includes gasket cross-webs  120  configured to provide additional support to the gasket  108 . In some embodiments, the cross-webs  120  extend across the internal chamber of the collection tank  100 . In some embodiments, the gasket  108  further includes positioning shoulders  124  which guide placement of the gasket  108  within the interlock slots  112  (e.g., insuring that the cross-webs  120  are positioned properly within the collection tank  100  upon installation of the gasket  108  and/or maintaining a peripheral portion of the gasket  108  in proper position within a seat  111  defined by the tank reinforcement member  104 ). 
         [0045]    In operation, the tank reinforcement member  104  can be placed in the collection tank  100  immediately after the collection tank  100  is molded. Alternatively, the tank reinforcement member  104  can be placed in the collection tank  100  any time prior to usage. The collection tank  100  can be shaped and dimensioned to receive the tank reinforcement member  104  by a clearance fit, snap fit, press fit, or in any other mating manner. For example, the tank reinforcement member  104  illustrated in  FIGS. 1-3 ,  5 A, and  5 B mate with the collection tank  100  via multiple projection and aperture sets. This mating relationship can enable the projections and apertures to slide with respect to one another until reaching a limit of movement (e.g., a bottom of each aperture), thereby defining a positive stop for accurate placement of the tank reinforcement member  104  with respect to the collection tank  100 . Accurate placement of the tank reinforcement member  104  can allow for proper gasket placement and compression without contact or interference with the heat exchanger header. A locking feature or a heat staking operation can be used to provide further support and retain the tank reinforcement member  104  within the collection tank  100 . 
         [0046]    By virtue of the relationship between the gasket  108  and the tank reinforcement member  104  described above with regard to some embodiments of the present invention, the gasket  108  can be installed on the tank reinforcement member  104  (e.g., by pressing cross-webs  116  or other portions of the gasket  108  into apertures  112  in the tank reinforcement member  104 ), and the tank reinforcement member  104  and gasket  108  can be moved or otherwise manipulated by a user or machine for installation in the collection tank  100 . In those embodiments in which there is an interference fit of the gasket  108  with the tank reinforcement member  104  (e.g., within the apertures  112  described above), this movement or manipulation can even place the tank reinforcement member and gasket assembly in an inverted position. 
         [0047]    In light of the relationship between the gasket  108  and the tank reinforcement member  104  described above, assembly of a resulting heat exchanger can be simplified and improved. Also, the gasket  108  can be retained in proper position with respect to the collection tank  100  and header throughout the life of the heat exchanger. 
         [0048]    Although a separate tank reinforcement member  104  as described above is desirable in many applications, it should be noted that the tank reinforcement member  104  and any of the gasket retention features described above can instead be integral with the collection tank  100  (e.g., molded as part of the collection tank  100 ) in other embodiments. 
         [0049]      FIGS. 6A-6I  illustrate collection tank assemblies  210  with tank reinforcement members  203  according to other embodiments of the present invention. Like the illustrated embodiment of  FIGS. 1-5B  above, the collection tank assemblies  210  illustrated in  FIGS. 6A-6I  each have a collection tank  200  comprising a first collection tank portion  200 A and a header  204 , a tank reinforcement member  203 , and a gasket  208 . The illustrated collection tank assemblies  210  are well-suited, for example, to radiator and charge air cooler applications utilizing brazed or grommeted tube-to-header joints. As also provided in the embodiment of  FIGS. 1-5B  (but not shown therein), the header  204  can be attached to flat tubes received within slot-shaped openings  216  in the header  204 . The tubes can be fastened to and within the header  204  in a pressure-tight manner by soldering, welding, adhesive or cohesive bonding material, or in any other suitable manner. 
         [0050]    With reference to the embodiments of  FIGS. 6A-6F  and  6 H- 6 I, headers  204  illustrated therein have a generally curved central portion  220  and a peripheral shoulder  222  extending laterally therefrom. The curved central portion  220  presents a convex shape to the tubes and a concave shape to the interior of the collection tank  200 . The design of the illustrated header  204  provides an increase in strength of the header  204  and provides an increase in strength of the connections between the header  204  and tubes (not shown) by stiffening the header  204  near the tube-to-header joints. Also, the curved central portion  220  reduces pressure stresses in both the header gasket well  221  (i.e., the location in which the gasket  208  is retained) and in the tube noses. Therefore, it is possible to reduce the cross-sectional thickness of the individual components of the collection tank assembly  210  to achieve weight and cost savings. As a result of the increase in the mechanical strength of the header  204  (and more generally, of the collection tank assembly  210 ), the service life of the collection tank assembly  210  and of a correspondingly configured heat exchanger is increased without any additional material expenditures, heat exchanger components, or individual production steps. 
         [0051]    Also by virtue of the curved shape of the central header portion  220  described above and illustrated in  FIGS. 6A-6F , and  6 H- 8 , deformation of the header  204  is anticipated. It will be appreciated that under moderate collection tank pressures, deformation of a header  204  having no curvature is likely. However, due to the curved central portion  220  of the header  204 , when the curved central portion  220  of the header  204  is under pressure loading, the header  204  experiences a considerably reduced degree of deformation. As a result, mechanical load on the connections between inserted tubes and the header are reduced, and bending stress upon the header  204  (e.g., due to internal pressures of the collection tank  200 ) are converted into tensile stresses, thereby providing increased strength of the header  204  and the header-to-tube connections. Since the strength of the header  204  and/or of the header-to-tube connections can decrease toward the center of the header  204  in many embodiments, the curvature of the central portion  220  of the header  204  increases the strength of the header  204  in the center of the header  204 . 
         [0052]    With continued reference to the illustrated header embodiments of  FIGS. 6A-6F  and  6 H- 8 , the header  204  also has a substantially flat peripheral shoulder  222  which can extend about the entire periphery of the curved central portion  220 . This shoulder  222  can at least partially define a gasket well  221  (mentioned above) in which a gasket  208  between the header  204  and first collection tank portion  200 A is retained in any of the manners described above. 
         [0053]    In some embodiments, the header  204  of the collection tank  200  is manufactured from plastic, and is curved about a longitudinal axis of the collection tank  200 , thereby presenting a generally convex shape toward the tubes connected thereto, and a generally concave shape toward an interior of the collection tank  200 . In other embodiments, other header materials can instead be used as desired. Also, any of the material combinations described above in connection with the embodiment of  FIGS. 1-5B  are applicable in connection with  FIGS. 6A-6I . 
         [0054]    The tubes for connection to the headers  204  shown in  FIGS. 6A-6I  can have any cross-section shape desired. However, unique advantages can be achieved by the use of flat tubes (i.e., tubes having opposing substantially broad flat sides joined by opposing narrow sides) connected to the header  204 . 
         [0055]    The collection tank assemblies  210  illustrated in  FIGS. 6A-6F  and  6 H- 8  each have a tank reinforcement member  203 . The tank reinforcement member  203  can be substantially flat as shown in  FIGS. 6A-6F  and  6 H- 8 , and can have any number of reinforcing webs  212  extending across the interior of the collection tank  200  in longitudinal or lateral directions (thereby increasing the strength of the collection tank  200 ) without obstructing or significantly obstructing flow through the collection tank  200  to or from the tubes connected to the collection tank  200 . The tank reinforcement member  203  can be connected to the collection tank  200  in any of the manners described above. For example, in some embodiments, slots in the tank reinforcement member  203  accept collection tank features with a snap-fit, press-fit, or other mating engagement when the collection tank  200  is installed upon a core of a heat exchanger. As shown in  FIGS. 6A-6F  and  6 H- 6 I, in some embodiments the tank reinforcement member  203  is received within and/or lies upon the header  204 . In some embodiments, the tank reinforcement member  203  lies within and/or upon the shoulder  222  of the header  204 , and can extend beneath, below, or beside the gasket  208 . The tank reinforcement member  203  can increase the material thickness of the collection tank assembly  210  (e.g., doubling the thickness of the gasket well area  221 , for example), such as in an area of the collection tank  200  adjacent the gasket  208 . Also, the tank reinforcement member  203  can strengthen the collection tank  200  in various ways, such as by extending the capability of tank-to-header crimp joints in high-pressure applications. 
         [0056]    In some embodiments, the tank reinforcement member  203  can be assembled with the header  204  prior to or during core assembly. The tank reinforcement member  203  can be connected to the header  204 , for example, in any manner desired, including without limitation by brazing or welding, by Tox® rivets (Tox Pressotechnik GmbH &amp; Co. KG), or in any other manner desired. For example, a complete braze joint between the header  204  and tank reinforcement member  203  can be used in those embodiments in which the tank reinforcement member  203  at least partially defines a sealing surface for the gasket  208 . 
         [0057]    Some embodiments of the present invention utilize additional collection tank strengthening elements alone or in conjunction with any of those described above (e.g., the tank reinforcing members  104 ,  203 ). FIGS.  6 A and  6 G- 6 I provide examples of such strengthening elements. With reference first to  FIG. 6A , the collection tank  200  can be provided with one or more reinforcements  250  extending from one or more walls of the collection tank  200  to a position engaged with a tank reinforcement member  203  as shown schematically in  FIG. 6A . These reinforcements  250  can have any shape desired, such as elongated fingers as shown in  FIGS. 6A ,  6 H, and  6 I, wider plates as shown schematically in  FIG. 6G  (in which case the reinforcements  250  can compartmentalize the interior of the collection tank  200 , in some embodiments), and the like. Also, these reinforcements  250  can be integral with the collection tank  200  or can be separate elements permanently or releasably attached thereto in any manner. The reinforcements  250  can be positioned and oriented to engage the tank reinforcement member  203  so that flexure or other movement of the collection tank  200  can be limited. The reinforcements  250  can also be movable with respect to the tank reinforcement member  203  (e.g., by a sliding fit, one or more lost motion connections, and the like), thereby enabling force to be transmitted through the reinforcements  250  in one direction, but with no or limited ability for force transmission in an opposite or other direction. For example, it may be desirable for the reinforcements  250  to prevent outward bulging or flexure of a collection tank wall, while still permitting inward movement of the same wall, or to permit movement of one or more portions of the collection tank  200  (e.g., header flexure) responsive to varying heat exchanger tube expansion and contraction during operation of the heat exchanger. Although only two collection tank reinforcements  250  are shown in particular positions in  FIGS. 6A and 6G , and a particular number of such reinforcements are visible in  FIGS. 6H and 6I , it will be appreciated that any number of such reinforcements  250  extending across the interior of the collection tank  200  can be used, in many cases without disruption to flow within the collection tank  200 . 
         [0058]      FIGS. 9-13  illustrate heat exchangers utilizing various features according to some embodiments of the present invention. With reference to  FIGS. 9 ,  10 ,  12 , and  13 , an option for any of the curved header heat exchangers described above is to utilize curved grommets  228 . Such grommets  228  can be made from rubber, EPDM, or any other material suitable for providing a fluid-tight seal, and could be installed within the tube apertures of the header  204  or upon the ends of tubes being inserted within the tube apertures of the header  204 . With particular reference to  FIGS. 12 and 13 , the illustrated grommet  228  has an opening  232  similar to the openings  216  in the header  204 , and is also configured to receive a flat tube  224 . The grommets  228  in the illustrated embodiment are shaped to provide an interference fit with the exterior of the flat tubes in order to prevent fluid leakage through the header-to-tube joints, while still allowing tubes experiencing thermal expansion and contraction to move as necessary. Regardless of the cause of tube movement, such grommets  228  can enable the tubes to move independently of one another and of the header  204  (by sliding within the grommets  228 , in some cases). The grommet design can be used for plastic tank radiators, charge-air-coolers, all-aluminum tank and header designs, and a number of other heat exchanger applications. 
         [0059]    The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention.

Technology Classification (CPC): 5