Patent Publication Number: US-11662158-B2

Title: Heat exchanger plate and heat exchanger comprising such a heat exchanger plate

Description:
The present invention concerns a heat exchanger plate of a heat exchanger for a refrigerant fluid circulation circuit fitted for an automotive vehicle. The object of the present invention is such a heat exchanger plate and a heat exchanger comprising at least one of these plates. 
     An automotive vehicle is currently equipped with a heating, ventilating and air conditioning system, usually called the HVAC system, for thermally treating the air present in or sent inside a passenger compartment of the automotive vehicle. The HVAC system is associated with a refrigerant fluid circulation circuit inside which a refrigerant fluid circulates. The refrigerant fluid circulation circuit comprises successively a compressor, a condenser or gas cooler, an expansion device and a heat exchanger. The heat exchanger is housed inside the HVAC system to allow a heat exchange between the refrigerant fluid and an air flow that is circulating inside the HVAC system before being delivered inside the passenger compartment. 
     According to a mode of operation of the refrigerant fluid circulation circuit, the heat exchanger is used as an evaporator to cool down the air flow. In this case, the refrigerant fluid is compressed inside the compressor, then the refrigerant fluid is cooled inside the condenser or gas cooler, then the refrigerant fluid expands within the expansion device and finally the refrigerant fluid cools down the air flow passing through the heat exchanger. 
     The heat exchanger comprises a plurality of heat exchanger plates that are assembled together to make the heat exchanger. The heat exchanger plate has a rectangular shape and comprises openings that are extending from a first face of the heat exchanger plate to a second face of the heat exchanger plate. The openings are located at extremities or angles of the heat exchanger plate. Each opening is delimited by a collar that is arranged around the opening. 
     Two heat exchanger plates are joined together to make a tube and several tubes are assembled together to make the heat exchanger plate. The collars of two plates are assembled together as well as longitudinal edges and lateral edges of both heat exchanger plates to realize the tube. Then, the tubes are assembled together to realize the heat exchanger. Finally, the heat exchanger comprises two header boxes, made of the assembled collars, between which a core, made of the extended portion of the heat exchanger plates, is interposed. 
     Before being used in the refrigerant fluid circuit, the heat exchanger undergoes some tests to check its pressure resistance and to identify any assembling defects. For example, the heat exchanger undergoes pressure tests during which the refrigerant fluid inside the heat exchanger is currently at 100 bars pressure. This test pressure is much higher than a current utilization pressure of the refrigeration fluid that is in a range of 15 bars to 20 bars. 
     It appears that during the pressure tests the heat exchanger tends to go through differential deformations in the core and the header boxes. More specifically, the header boxes tend to be more extended than the core of the heat exchanger. These differential deformations may generate cracks within the heat exchanger that could provoke refrigerant fluid which is mostly inconvenient. 
     There is a need to have a heat exchanger comprising heat exchanger plates that are arranged so that no leak appear in order to have a robust and sustainable heat exchanger. 
     The heat exchanger plate of the invention is a heat exchanger plate of a heat exchanger. The heat exchanger plate comprises two faces extending between two lateral edges and two longitudinal edges of said heat exchanger plate. The heat exchanger plate comprises at least an opening extending from a first face to a second face of the heat exchanger plate. The opening is delimited by a collar that is arranged around the opening. The heat exchanger plate comprises at least a dimple protruding above at least one of the faces. 
     According to the invention, said dimple comprises at least a flat area and a sloped area, said sloped area being interposed between the collar and the flat area. 
     The heat exchanger plate is also advantageously characterized by any of the following characteristics, these characteristics being combined or considered alone:
         the lateral edges and the longitudinal edges are perpendicular to each other,   the lateral edges are parallel to each other.   the longitudinal edges are parallel to each other,   the longitudinal edges are longer than the lateral edges,   the opening is circular.   the opening is elliptical,   the heat exchanger plate comprises at least two openings aligned along one of the lateral edges. In one embodiment, the beat exchanger plate comprises four openings each located at an angle of the heat exchanger plate,   two of the openings are close to a first lateral edge and two of the openings are close to a second lateral edge,   the heat exchanger plate comprises at least a dimple extending from at least one of the faces,   the dimple forms a protrusion over one of the faces,   the dimple is extended along a transversal axis that is perpendicular to the longitudinal edges and the lateral edges,   the sloped area has a cross-section that has a U-shape form between the flat area and the collar,   the sloped area has a cross-section that has a S-shape form between the flat area and the collar,   the cross section is taken in a central plane parallel to the longitudinal edges and perpendicular to lateral edges,   two heat exchanger plates are assembled together to make a tube of the heat exchanger,   the collar protrudes with respect to the first face of the heat exchanger plate and the dimple protrudes with respect to the second face of the heat exchanger plate,   the dimple is located between the collar and a core portion of the heat exchanger plate, the dimple and the core portion being separated by a borderline,   the borderline is a limit of the heat exchanger plate located between a collecting portion of the heat exchanger plate and the core portion of said heat exchanger plate,   the collecting portion of the heat exchanger plate comprises at least the collar,   the collecting portion of the heat exchanger plate is dedicated to permit the circulation of a refrigerant fluid from one tube to another of the heat exchanger,   the core portion of the heat exchanger plate comprises at least the grooves,   the core portion of the heat exchanger is dedicated to facilitating the heat exchange between the refrigerant fluid circulating in the heat exchanger and an air flow circulating in the air conditioning system,   the flat area of the dimple is arranged in a first plane that is parallel to a second plane in which the core portion of the heat exchanger plate is arranged,   the borderline has a sinusoidal shape,   the shape of the borderline is observed from a view point located in a plane parallel to the second plane.   the sloped area being delimited by two opposite side lines, a first distance between both side lines increases from the flat area of the dimple up to the collar,   each side line is a limit between the dimple and the core portion of the heat exchanger plate,   the side lines are parts of the borderline,   the sloped area being a curved area, the curvature center of the curved area is located at a second distance that is bigger than a depth of the dimple,   the depth of the dimple is measured between the first plane and the second plane,   the sloped area comprises a fringe that is tangent to the collar,   the heat exchanger plate comprises a plurality of dimples that are symmetrically arranged versus a central plane that is parallel to the longitudinal edges of the heat exchanger plate and passing by an opening center of the opening,   each dimple comprising a summit, the summits of the dimples are arranged on a dimple circle, a center of the dimple circle being the opening center.   a third distance between the opening center of the opening and a limit between the sloped area and the flat area is constant from one dimple to another dimple,   the distance between the center of the opening and the limit between the sloped area and the flat area is taken between the opening center of the opening and a middle point of the said limit, that is to say at equal distance of each side lines of the sloped area,   a thickness of the sloped area is at least constant from the limit up to the collar.   the thickness of the sloped area is measured between both faces of the heat exchanger plate in die sloped area, perpendicularly of at least one face,   the thickness of the sloped area is increasing from the limit up to the collar,   the heat exchanger plate comprises at least a groove that is located in the core portion of the heat exchanger plate,   the groove is longitudinally extended in a parallel direction to the longitudinal edges,   the groove protrudes with respect to the second face of die heat exchanger plate,   the groove and the dimple emerge over the same face of the heat exchanger plate,   the heat exchanger plate comprises a plurality of grooves, each groove extending from a first longitudinal extremity and a second longitudinal extremity, both longitudinal extremities being located along a groove axis that is parallel to the longitudinal edges of the heat exchanger plate,   the summit of the dimple is located in a canal that is delimited by at least a groove.   a dimple is a prolongation of a groove,   the flat area of the dimple is a prolongation of a groove,   the dimple comprises a chamfer, a width of the chamfer of the sloped area being bigger than a width of the chamfer of the flat area,   the sloped area and the flat area are arranged around a line of symmetry that is a straight line.   the sloped area and the flat area are arranged around a line of symmetry that is a curved line.       

     The invention relates also to a heat exchanger comprising at least one such heat exchanger plate. 
     The heat exchanger plate is also advantageously characterized by any of the following characteristics, these characteristics being combined or considered alone:
         the heat exchanger comprises a first heat exchanger plate and a second heat exchanger plate, the flat area of both heat exchanger plates being in contact with each other,   the flat area of both heat exchanger plates are brazed together.       

     The invention relates also to a refrigerant fluid circulation circuit that comprises at least such a heat exchanger. 
     The invention relates also to utilization of the heat exchanger as an evaporator in such a refrigerant fluid circulation circuit. 
     The invention relates also to a method for manufacturing such a heat exchanger plate comprises at least:
         a step in which the collar is stamped from the first face of the heat exchanger plate to the second face of the heat exchanger face,   a step in which the dimple and the groove are stamped from the second face of the heat exchanger plate to the first face of the heat exchanger face.       

    
    
     
       Other specificities, details and characteristics of the present invention will be highlighted thanks to the following description, given for general guidance, in relation with the following figures: 
         FIG.  1    is a general view of a heat exchanger according to the present invention, 
         FIG.  2    is a partial view of the heat exchanger illustrated in  FIG.  1   , 
         FIG.  3    is a face view of a heat exchanger plate participating to the heat exchanger illustrated in  FIG.  1  or  2   , 
         FIG.  4    is a partial view of the heat exchanger plate illustrated in  FIG.  3   , 
         FIG.  5    is a partial cross-section view of the heat exchanger plate illustrated in  FIGS.  3  and  4   , 
         FIG.  6    is a partial face view of the heat exchanger plate illustrated in  FIGS.  3  to  5   , 
         FIG.  7    is a schematic view of a refrigerant fluid circulation circuit comprising the heat exchanger illustrated in  FIG.  1   . 
     
    
    
     In the Figures, a heat exchanger  1  according to the invention is shown in a coordinate system Oxyz in which Ox axis is a longitudinal axis, Oy axis is a lateral axis and Oz axis is a transversal axis, the Oxz plane is a longitudinal plane, the Oxy plane is a lateral plane and the Oyz plane is a transversal plane. In the following description, a direction is qualified in accordance with the above mentioned axis and a surface is qualified in accordance with the above mentioned plane. 
     In  FIG.  1   , the heat exchanger  1  comprises a core  2  disposed between two header boxes  3 . The core  2  is the part of the heat exchanger  1  that is dedicated to enable a heat exchange between a refrigerant fluid  4  circulating in the heat exchanger  1  and an air flow  5  passing through the heat exchanger  1 . Both header boxes  3  extend mainly in a transversal direction A 1  that is parallel to the Oz axis. The core  2  comprises a plurality of tubes  6  that are interposed between the header boxes  3 . 
     The tubes  6  extend mainly along a longitudinal direction A 2  that is parallel to the longitudinal axis Ox. The tubes  6  are also laterally extended along a lateral direction A 3  that is parallel to the Oy axis. The lateral direction A 3  is also perpendicular to a longitudinal plane P 1  of the heat exchanger  1  containing the header boxes  3  and the tubes  6 . Therefore, the tubes  6  are disposed in respective planes that are parallel to a lateral plane P 2 , the lateral plane P 2  being perpendicular to the longitudinal plane P 1  of the heat exchanger  1 . In other words, the tubes  6  altogether form the core  2  that is globally arranged as a parallelepiped. 
     The heat exchanger  1  is equipped with a refrigerant fluid inlet  7  through which the refrigerant fluid  4  is admitted inside the heat exchanger  1 . The refrigerant fluid inlet  7  equips the header box  3 . The heat exchanger  1  is also equipped with a refrigerant fluid outlet  8  through which the refrigerant fluid  4  is evacuated from the heat exchanger  1 . The refrigerant fluid outlet  8  equips the same header box  3  than the refrigerant fluid inlet  7 . Furthermore, the refrigerant fluid inlet  7  and the refrigerant fluid outlet  8  are located on the same longitudinal side of the heat exchanger  1 . Therefore, in this embodiment of the invention, the refrigerant fluid  4  circulates along a path that is designed as a U form path. Other localization of the refrigerant fluid inlet  7  and the refrigerant fluid outlet  8  are possible, so that the heat exchanger  1  of the invention may provide a I form path or a W form path or other combinations of path for the refrigerant fluid  4 . 
     The core  2  comprises these tubes  6  and corrugated fins  9  that are separating two contiguous tubes  6 , the corrugated fins  9  enhancing the heat exchange between the refrigerant fluid  4  and the air flow  5 . 
       FIG.  2    represents a tube  6  that is a flat tube formed by assembling a pair of heat exchanger plates  10 . The heat exchanger plates  10  have globally a rectangular shape that extends in the lateral plane P 2 . Both heat exchanger plates  10  extend in respective planes parallel to the lateral plane P 2 , thus making the tube  6  planar. The pair of heat exchanger plates  10  is designed to allow the circulation of the refrigerant fluid in at least a dedicated canal  11 . Each heat exchanger plate  10  has a first face  12  and a second face  13  opposed to the first face  12 . When the heat exchanger plates  10  are assembled together, the first face  12  of a first heat exchanger plate  10  of a pair faces the first face  12  of a second heat exchanger plate  10  of the same pair. Then, the first heat exchanger plate  10  and the second heat exchanger plate  10  are brazed in order to delimit the canal  11 . 
     In  FIG.  3   , the heat exchanger plate  10  extends between two lateral edges  14  and two longitudinal edges  15  of said heat exchanger plate  10 . The lateral edges  14  and the longitudinal edges  15  are perpendicular to each other. The lateral edges  14  are parallel to each other and the longitudinal edges  14  are parallel to each other as well. The longitudinal edges  15  are longer than the lateral edges  14 . All together the lateral edges  14  and the longitudinal edges  15  form a quadrilateral. 
     The heat exchanger plate  10  comprises four openings  16  that are extending from the first face  12  to the second face  13  of the heat exchanger plate  10  along the transversal direction A 1 . The openings  16  are located at the angle of the quadrilateral formed together by the lateral edges  14  and the longitudinal edges  15 . The openings  16  can be either circular or elliptical. When two heat exchanger plates  10  are assembled together, the openings  16  are aligned along the transversal direction A 1  to enable a fluid circulation from one tube  6  to another tube  6  within the heat exchanger  1 . Therefore, the forms of the openings  16  of all the heat exchanger plates  10  are similar to permit such a refrigerant fluid circulation. Among the four openings  16 , two of the openings  16  are close to a first lateral edge  14  and two of the openings  16  are close to a second lateral edge  14 . 
     The heat exchanger plate  10  comprises a core portion  23  that is interposed between two collecting portions  25  gathering the openings  16 . The core portion  23  of the heat exchanger plate  10  participates to the core  2  of the heat exchanger  1  that is receiving the corrugated fins  9  and where the heat transfer between the refrigerant fluid  4  and the air flow  5  mainly occur. The collecting portion  25  of the heat exchanger plate  10  participates to the part of the heat exchanger  1  that is collecting the refrigerant fluid  4  from one tube  6  to another tube  6 . 
     The core portion  23  comprises a plurality of grooves  26  that are longitudinally extended in a parallel direction to the longitudinal edges  15 . Some canals  11  are delimited by two grooves  26  and some canals  11  are delimited by a groove  16  and a longitudinal edge  25 . Grooves  26  of two assembled heat exchanger plates are brazed together to delimit the canals  11 . The grooves emerge over the second face  13  of the heat exchanger plate  10 . 
     Each groove  26  extends from a first longitudinal extremity  33  and a second longitudinal extremity  32 , both longitudinal extremities  32 ,  33  being located along a groove axis A 4  that is parallel to the longitudinal edges  15  of the heat exchanger plate  10 . 
       FIG.  4    shows that each opening  16  is delimited by a collar  17  that is arranged around the opening  16 . Each collar  17  forms an extension of the heat exchanger plate  10  along the transversal direction A 1  and around the opening  16 . In other words, the collar forms a protrusion of the heat exchanger plate  10  over the first face  12  of the heat exchanger plate  10 . The collars  17  of a heat exchanger plate  10  are all similar and are all extending from the second face  13  up to the first face  12 . 
     The heat exchanger plate  10  comprises a plurality of dimples  18  that are protruding above the second face  13  of the heat exchanger plate  10 . Each dimple  18  is a deformation of the heat exchanger plate  10  that extends from the first face  12  up to the second face  13 . In other words, each dimple  18  forms a protrusion over the second face  13 . That is to say that the dimples  18  and the collars  17  are formed in an opposite sense along the transversal direction A 1 . The grooves  26  and the dimples  18  emerge over the same face of the heat exchanger plate  10 , i.e. the second face  13 . 
     Each dimple  18  is located between the collar  17  and the core portion  23  of the heat exchanger plate  10 , the dimple  18  and the core portion  23  being separated by a borderline  24 . The borderline  24  is a limit of the heat exchanger plate  10  that is located between the collecting portion  25  of the heat exchanger plate  10  and the core portion  23  of said heat exchanger plate  10 . The collecting portion  25  of the heat exchanger plate  10  comprises at least the collars  17 . The flat area  19  of the dimple  18  is arranged in a first plane P 1  that is parallel to a second plane P 2  in which the core portion  23  of the heat exchanger plate  10  is arranged. The borderline  24  has a sinusoidal shape when observed from a view point located in a plane parallel to the second plane P 2 . 
     Each dimple  18  comprises a flat area  19  and a sloped area  20 . The sloped area  20  is interposed between the collar  17  and the flat area  19 . The flat area  19  is arranged in a plane that is parallel to the lateral plane P 2 . The sloped area  20  joins together the flat area  19  and the collar  17 . 
       FIG.  5    represents a cross section of the dimple  18  taken in a central plane P 3  that is perpendicular to the lateral plane P 2  and that is passing through a center  21  of the opening  16 . The sloped area  20  has a cross-section that has a S-shape form between the flat area  19  and the collar  17 . The sloped area  20  comprises a fringe  22  that is tangent to the collar  17 . The flat area  19  and the sloped area  20  form together an angle α that is different than 0°. The angle α is measured between both general extension directions of the flat area  19  and the sloped area  20 . 
     The sloped area  20  is a curved area, the curvature center  29  of the curved area is located at a first distance D 2  that is bigger than a depth P of the dimple  118 . The depth P of the dimple  18  is measured between the first plane P 1  and the second plane P 2 . 
       FIG.  6    features a heat exchanger plate  10  equipped with a plurality of dimples  18  whom sloped area  20  is delimited by two opposite side lines  27 , a second distance D 1  between the two side lines  27  increases from the flat area  19  of the dimple  18  up to the collar  17 . That is to say that the distance D 1  between two side lines  27  increases from a summit  28  of the dimple  18  up to the collar  17 . Each side line  27  is a limit between the dimple  18  and the core portion  23  of the heat exchanger plate  10 . Both opposite side lines  27  are parts of the borderline  24 . 
     The dimples  18  are symmetrically arranged versus the central plane P 3  that is parallel to the longitudinal edges  15  of the heat exchanger plate  10  and passing by the opening center  21  of the opening  16 . 
     The summits  28  of the dimples  18  are arranged on a dimple circle  30 , a center of the dimple circle  30  being the opening center  21 . 
     A third distance D 3  between the opening center  21  of the opening  16  and a limit  31  between the sloped area  20  and the flat area  19  is constant from one dimple  18  to another dimple  18 . The third distance D 3  between the opening center  21  of the opening  16  and the limit  31  between the sloped area  20  and the flat area  19  is taken between the opening center  21  of the opening  16  and a middle point  34  of the said limit  31 , that is to say at equal distance of each side lines  27  of the sloped area  20 . 
     As featured in  FIG.  5   , a thickness T of the sloped area  20  is at least constant from the limit  31  up to the collar  17 . The thickness T of the sloped area  20  is measured between both faces  12 ,  13  of the heat exchanger plate  10  in the sloped area  20 , perpendicularly of at least one face  12 ,  13 . In another embodiment of the invention, the thickness T of the sloped area  20  is increasing from the limit  21  up to the collar  17 . 
     The summit  28  of each dimple  18  is located in the canal  11  that is delimited by at least a groove  26 . 
     In another embodiment of the invention, a dimple  18  is a prolongation of a groove  26 . More precisely, the flat area  19  of the dimple  18  is a prolongation of a groove  26 . 
     The dimple  18  comprises a chamfer  35 , a width W of the chamfer  35  of the sloped area  20  being bigger than a width W of the chamfer  35  of the flat area  19 . 
     The sloped area  20  and the flat area  19  are arranged around a line of symmetry  36  that is a curved line. In another embodiment of the invention, the sloped area  20  and the flat area  19  are arranged around a line of symmetry  36  that is a straight line. 
     The heat exchanger partially featured in  FIG.  2    comprises a first heat exchanger plate  10  and a second heat exchanger plate  10  as described above, the flat area  19  of both heat exchanger plates  10  are in contact with each other. More precisely, the flat area  19  of both heat exchanger plates  10  are brazed together. 
     This comforts the resistance of the heat exchanger  1  during a pressure test in which the refrigerant fluid is at a pressure of 100 bars inside in the heat exchanger. Such a configuration of the heat exchanger  1  avoids any cracks within the heat exchanger plate  10  and any leaks of refrigerant fluid  4  from the heat exchanger  1 . 
       FIG.  7    illustrates a refrigerant fluid circulation circuit  100  inside which circulates the refrigerant fluid  4 . Following a direction Si of circulation of the refrigerant fluid  4  inside the refrigerant fluid circulation circuit  100 , the refrigerant fluid circulation circuit  100  successively comprises a compressor  101  for compressing the refrigerant fluid  4 , a condenser or a gas cooler  102  for cooling the refrigerant fluid  4 , an expansion device  103  inside which the refrigerant fluid  4  expands and the heat exchanger  1 . The heat exchanger  1  is accommodated inside an air duct  104  of a heating, ventilating and air conditioning system  105  inside which circulates the air flow  5 . The heat exchanger  1  allows a heat transfer between the refrigerant fluid  4  and the air flow  5  coming into contact with it and/or passing through it, as illustrated in  FIG.  1   . According to the operating mode of the refrigerant circuit  1  described above, the heat exchanger  1  is used as an evaporator for cooling the air flow  5 , during the passage of the air flow  5  in contact with and/or from one side of the beat exchanger  1 . 
     In view of the foregoing, proposed herein is a reinforced design of heat exchanger plate that is more resistant at working pressure and burst pressure in view of the sloped area that is interposed between the collar and the flat area of the dimple. The heat exchanger tube that uses such plate is easily manufactured, at a low cost. It allows good thermal exchange performance. This heat exchanger tube is dedicated to heat exchanger and can be found in a Heating, Ventilation and Air-Conditioning device of a motor vehicle. This kind of heat exchanger can be easily integrated into vehicle air conditioning systems in order to optimize the heat exchange between the air flow dedicated to the passenger compartment cool down and the refrigerant fluid circulating inside heat exchanger tubes of the invention. 
     However, the invention is not limited to resources and patterns described and illustrated here. It also includes all equivalent resources or patterns and every technical associations including such resources. More particularly, the shape of the heat exchanger plate does not affect the invention, insofar as the heat exchanger plate for use in a motor vehicle, in fine, has the same functionality as describes in this document.