Patent Publication Number: US-2011073277-A1

Title: Adapter for heat exchanger

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 61/082,957, which was filed Jul. 23, 2008. 
    
    
     BACKGROUND OF THE INVENTION 
     As shown in  FIG. 1 , a prior art heat exchanger  36  of a refrigeration system includes tubes  38  extending between two header plates  40  and  42 . A refrigerant flows though the tubes  38  and exchanges heat with air that flows over the tubes  38 . Refrigerant flows in a first direction A through a tube  38 . The refrigerant exits the tubes  38 , flows through a u-shaped tube  44  (or hairpin tube), and then flows through another tube  38  in an opposing second direction B. During manufacture of the heat exchanger  36 , the tubes  38  are bent or formed into a desired shape by a forming machine. The forming machine engages the u-shaped tubes  44  and bends or forms the tubes  38  to the desired shape. 
     A microchannel heat exchanger includes a plurality of flat tubes extending between two manifolds. The microchannel heat exchanger does not include header plates or u-shaped tubes. The manifolds at the ends of the tubes of the microchannel heat exchanger have a different structure than the header plates at the ends of the tubes of the prior art heat exchanger and do not include the u-shaped tubes that can be engaged by the forming machine. 
     In one prior heat exchanger described in U.S. Pat. No. 5,964,281, an adapter is attached to the heat exchanger to create new inlet and outlet port locations to allow the heat exchanger to be employed in different environments. The adapter is attached to ends of the headers of the heat exchanger. The adapter is substantially perpendicular to the headers and substantially parallel to the plurality of tubes. 
     SUMMARY OF THE INVENTION 
     A heat exchanger includes a first manifold, a second manifold and a plurality of tubes extending between the first manifold and the second manifold. An adapter is mounted to the first manifold, and the adapter includes a plurality of engagement features engageable by a forming machine to form the heat exchanger into a shape. 
     Another illustrative embodiment provides an adapter attachable to a manifold of a heat exchanger. The adapter includes a curved wall, a plurality of attachment members located on a first side of the curved wall, and a plurality of u-shaped members located on an opposing second side of the curved wall. The plurality of attachment members and the curved wall define a space to receive a manifold of a heat exchanger. 
     These and other features of the present invention will be best understood from the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various features and advantages of the invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows: 
         FIG. 1  schematically illustrates a prior art heat exchanger; 
         FIG. 2  schematically illustrates a prior art refrigeration system; 
         FIG. 3  schematically illustrates a microchannel heat exchanger before the microchannel tubes are formed; 
         FIG. 4  schematically illustrates a forming machine engaging an adapter of the microchannel heat exchanger; 
         FIG. 5  schematically illustrates a perspective view of the adapter; 
         FIG. 6  schematically illustrates an enlarged view of the adapter of  FIG. 5 ; 
         FIG. 7  schematically illustrates another perspective view of the adapter; 
         FIG. 8  schematically illustrates a perspective view of the adapter and a return manifold prior to attachment; 
         FIG. 9  schematically illustrates a perspective view of the adapter attached to the return manifold; 
         FIG. 10  schematically illustrates another perspective view of the adapter attached to the return manifold; 
         FIG. 11  schematically illustrates a perspective view of the microchannel heat exchanger after the microchannel tubes are formed; 
         FIG. 12  schematically illustrates a perspective view of the microchannel heat exchanger mounted in a cabinet; and 
         FIG. 13  schematically illustrates a side view of the microchannel heat exchanger mounted to the cabinet. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 2  schematically illustrates a refrigeration system  20  including a compressor  22 , a first heat exchanger  24 , an expansion device  26 , and a second heat exchanger  28 . Refrigerant circulates through the closed circuit refrigeration system  20 . 
     When the refrigeration system  20  is operating in a cooling mode, the refrigerant exits the compressor  22  at a high pressure and a high enthalpy and flows through the first heat exchanger  24 , which acts as a condenser. In the first heat exchanger  24 , the refrigerant rejects heat to air and is condensed into a liquid that exits the first heat exchanger  24  at a low enthalpy and a high pressure. A fan  30  directs the air through the first heat exchanger  24 . The cooled refrigerant then passes through the expansion device  26 , expanding the refrigerant to a low pressure. After expansion, the refrigerant flows through the second heat exchanger  28 , which acts as an evaporator. In the second heat exchanger  28 , the refrigerant accepts heat from air, exiting the second heat exchanger  28  at a high enthalpy and a low pressure. A fan  32  blows air through the second heat exchanger  28 . The refrigerant then flows to the compressor  22 , completing the cycle. 
     When the refrigeration system  20  is operating in a heating mode, the flow of the refrigerant is reversed with a four-way valve  34 . The first heat exchanger  24  accepts heat from the air and functions as an evaporator, and the second heat exchanger  28  rejects heat to the air and functions as a condenser. 
     Either or both of the heat exchangers  24  and  28  can be a microchannel heat exchanger  46 . The microchannel heat exchanger  46  can be used, for example, with a microdevice, an automobile air conditioner, a residential system, or any type of system. For ease of reference, the microchannel heat exchanger can be referred to as a microchannel heat exchanger  46 . 
       FIG. 3  illustrates the microchannel heat exchanger  46  before being formed. The microchannel heat exchanger  46  includes an inlet/outlet manifold  48 , a return manifold  50 , and a plurality of flat microchannel tubes  52  that extend between the manifolds  48  and  50 . The manifolds  48  and  50  are substantially cylindrical and have a diameter Y. The microchannel tubes  52  are substantially parallel. Each microchannel tube  52  is a flat multi-port tube, and each port has a hydraulic diameter of less than 1 mm. A plurality of fins  140  are located between adjacent microchannel tubes  52  to increase heat transfer. 
     In one example, the refrigerant makes two passes through the microchannel heat exchanger  46  (referred to as a circuit). A pass is defined as one trip through the microchannel tubes  52  between the manifolds  48  and  50 . However, the refrigerant can make any number of passes through the circuit. For example, the refrigerant can make only one pass or can make more than two passes through the microchannel heat exchanger  46 . Although only one circuit is illustrated and described, the microchannel heat exchanger  46  can include multiple independent and separate refrigerant circuits. 
     The refrigerant enters the microchannel heat exchanger  46  through an inlet tube  54  and is directed into an inlet section  56  of the inlet/outlet manifold  48 . The refrigerant flows in a first direction A through a group microchannel tubes  52  and enters the return manifold  50 . The return manifold  50  directs the refrigerant through another group microchannel tubes  52 , and the refrigerant flows in an opposing second direction B and into an outlet section  58  of inlet/outlet manifold  48 . The refrigerant exits the microchannel heat exchanger  46  through an outlet tube  60 . The inlet section  56  and the outlet section  58  of the inlet/outlet manifold  48  are separated by a divider wall  62  to prevent fluid communication therebetween. As the refrigerant flows through the microchannel tubes  52 , the refrigerant exchanges heat with air that flows over the microchannel tubes  52 . 
     The microchannel heat exchanger  46  does not include the u-shaped tubes  44  of the prior art heat exchanger  36 . An adapter  68  is attached to the return manifold  50  during assembly to simulate the configuration and structure of the prior art heat exchanger  36 . 
     As shown schematically in  FIG. 4 , the microchannel heat exchanger  46  is formed or bent into a desired shape by a forming machine  64 . The forming machine  64  includes a forming arm  66  that engages the adapter  68  to form or bend the microchannel heat exchanger  46  into a desired shape. The adapter  68  allows the microchannel heat exchanger  46  to simulate the structure and configuration of the prior art heat exchangers  36 , allowing known forming machines  64  to be used. The forming machine  64  and its forming arm  66  can engage the adapter  68  to form or bend the microchannel heat exchanger  46  into the desired shape without requiring modification to the forming machine  64  or the forming arm  66 . 
       FIGS. 5 ,  6  and  7  illustrate the adapter  68 . The adapter  68  is a single, unitary component. The adapter  68  is attached to the return manifold  50  of the microchannel heat exchanger  46 . In one example, the adapter  68  is made of injection molded plastic. The adapter  68  has a length X and includes a plurality of fasteners  70  (a plurality of attachment members). Each fastener  70  is spaced along the length X of the adapter  68  and includes a flexible first arm  74  and a flexible second arm  76 . The adapter  68  includes a curved wall  72  having a first side  78  that faces the return manifold  50  and an opposing second side  80  that faces away from the return manifold  50 . The arms  74  and  76  extend from the first side  78  of the curved wall  72  (shown in  FIGS. 5 and 6 ). 
     As further shown in  FIG. 6 , the first arm  74  and the second arm  76  each includes a curved surface  82  having a curvature that matches the curvature of the return manifold  50 . A space  84  is defined by the curved wall  72  and the curved surfaces  82  of the first arm  74  and the second arm  76  and defines a circular opening having a shape that corresponds to the shape of the return manifold  50 . An opening  86  having a width W is defined between the first arm  74  and the second arm  76 . Before attachment of the adapter  68  to the return manifold  50 , the width W of the opening  86  is less than the diameter Y of the return manifold  50 . As the first arm  74  and the second arm  76  are flexible, the width W of the opening  86  can increase. 
     In one example, the curved wall  72  includes segments  88  spaced apart by openings  89 . The openings  89  are spaced equally along the length X of the adapter  68 . The curved wall  72  can also include an opening  90  within each segment  88 . The openings  89  and  90  are formed during the injection molding process and can have any shape. 
     The adapter  68  also includes a first wall  92  and a second wall  94  that extend from the second side  80  of the curved wall  72  (shown in  FIG. 7 ). The walls  92  and  94  provide structural support and rigidity to the adapter  68 . The first wall  92  includes a first portion  96  and a second portion  98 . The first portion  96  connects the second portion  98  to the curved wall  72 . 
     The second portion  98  of the first wall  92  and the second wall  94  are substantially parallel and extend in a direction opposite to the first arm  74  and the second arm  76 . The first portion  96  includes a plurality of apertures  100  spaced along the length X of the adapter  68 . When the microchannel heat exchanger  46  is assembled, the plurality of apertures  100  receive wires of a wire grill (not shown) that surrounds the microchannel heat exchanger  46  to provide protection from debris and objects, such as leaves. 
     As shown in  FIGS. 12 and 13 , the second wall  94  of the adapter  68  includes a plurality of apertures  104  that can each receive a fastener  122 , such as a screw, that secures the adapter  68 , and therefore the microchannel heat exchanger  46 , to a surrounding cabinet  124 . 
     In one example, one or both of the first wall  92  and the second wall  94  includes a sheet metal strip (not shown) to provide additional structure and support to the adapter  68 . The sheet metal strip can be attached to a surface of the first wall  92  or the second wall  94  or can be impregnated in the first wall  92  or the second wall  94  during the injection molding process. 
     A plurality of u-shaped members  106  (a plurality of engagement features) extend from the second side  80  of the curved wall  72  and are located between the first wall  92  and the second wall  94 . The u-shaped members  106  are equally spaced along the length X of the adapter  68 . The u-shaped members  106  have a size and shape similar to the u-shaped tubes  44  of the prior art heat exchanger  36  and simulate the u-shaped tubes  44 . 
     The adapter  68  is attached to the return manifold  50  of the microchannel heat exchanger  46 . The adapter  68  is attached by the plurality of fasteners  70  to a body  51  of the return manifold  50 . That is, the adapter  68  is attached between the ends  53  and  55  of the return manifold  50 . When the adapter  68  is attached to the return manifold  50 , the adapter  68  is substantially parallel to the return header  50  and substantially perpendicular to the plurality of microchannel tubes  52 . As shown in  FIG. 8 , prior to attachment, the adapter  68  is positioned such that the first side  78  of the curved wall  72  faces the return manifold  50 . The diameter Y of the return manifold  50  is greater than the width W of the opening  86  defined between the first arm  74  and the second arm  76 . The return manifold  50  is positioned between the first arm  74  and the second arm  76 , biasing the flexible arms  74  and  76  apart and increasing the width W of the opening  86  to allow the return manifold  50  to pass between the arms  74  and  76  and to be received inside the space  84 . The first arm  74  and the second arm  76  return to the original position, retaining the adapter  68  on the return manifold  50 . 
       FIGS. 9 and 10  illustrate a perspective view of the adapter  68  attached to the return manifold  50  of the microchannel heat exchanger  46 . The u-shaped members  106  extend from the second side  80  of the curved wall  72  and simulate the u-shaped tubes  44  of the prior art heat exchanger  36 . 
     As shown in  FIG. 11 , a second adapter  108  can be attached to the inlet/outlet manifold  48 . The second adapter  108  attaches to the inlet/outlet manifold  48  in the same manner as the adapter  68  attaches to the return manifold  50 . The second adapter  108  includes fasteners (not shown) that correspond to the fasteners  70  of the adapter  68 , and the second adapter  108  includes a first wall  110  and a second wall  112  that correspond to the first wall  92  and the second wall  94 , respectively, of the adapter  68 . The second wall  112  includes apertures  132  that receive a fastener (not shown) to secure the microchannel heat exchanger  46  to the cabinet (not shown), and the first wall  110  includes apertures (not shown) that receive wires of the wire grill that provides protection. The second adapter  108  also includes an inlet port  114  in fluid communication with the inlet tube  54 , and an outlet port  116  in fluid communication with the outlet tube  60 . 
     During forming or bending of the microchannel heat exchanger  46 , the forming arm  66  of the forming machine  64  engages and interacts with the u-shaped members  106  of the adapter  68  in the same manner that the forming arm  66  engages the u-shaped tubes  44  of the prior art heat exchanger  36 . The forming machine  64  then forms or bends the microchannel tubes  52  in three locations  126   a,    126   b  and  126   c  such that the length of the microchannel tubes  52  define a substantially square shape that surrounds a space  122 . The resulting bent microchannel tubes  52  defines a first side  118   a,  a second side  118   b,  a third side  118   c  and a fourth side  118   d.    
     When the adapter  68  is attached to the return manifold  50 , the microchannel heat exchanger  46  can be formed or bent by the same forming machine  64  that forms or bends the prior art heat exchangers  36 , allowing the prior art heat exchanger  36  and the microchannel heat exchanger  46  to be formed on the same assembly line or concurrently on the same assembly line, increasing efficiency of the production and preventing the need for a separate forming machine for the microchannel heat exchanger  46 . Once the microchannel tubes  52  are formed or bent, the forming machine  64  disengages from the u-shaped members  106  of the microchannel heat exchanger  46 . 
     The adapter  68  also assists in attachment of the microchannel heat exchanger  46  to the cabinet that contains or covers the microchannel heat exchanger  46 . When adapter  68  is attached to the microchannel heat exchanger  46 , the adapter  68  slightly raises the microchannel heat exchanger  46 . In one example, the microchannel heat exchanger  146  is raised half an inch by the adapter  68 . The fan  30  or  32  (shown in  FIG. 2 ) can be installed in the space  122  defined by the four walls  102   a,    102   b,    102   c  and  102   d  to draw air over the microchannel tubes  52  during heat exchange. A base pan  120  (see  FIG. 10 ) is received under the microchannel tubes  52  of the microchannel heat exchanger  46 . The cabinet is positioned over the microchannel heat exchanger  46 , and the fasteners (not shown) are received in the apertures  104  and  132  of the walls  94  and  112 , respectively, to attach the adapters  68  and  108 , respectively, to the cabinet. 
     The foregoing description is only exemplary of the principles of the invention. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, so that one of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.