Abstract:
The present document discloses a plate type heat exchanger for an oil cooler, comprising at least two heat exchanger members, each enclosing a respective first cavity (C 1 ), at least one inlet port ( 20, 22 ), for feeding a medium to the first cavities and at least one output port ( 21, 23 ) for extracting the medium from the first cavities (C 1 ); and at least one mounting member ( 13, 14 ), which is attached to an outside of an outermost one, as seen in a stacking direction (Z), of the heat exchanger members. A second cavity (C 2 ) is formed between the at least two heat exchanger members. A medium present in the second cavity (C 2 ) is isolated from a medium present in the first cavities (C 1 ). A reinforcement plate ( 30, 31 ) is located on an inside of the outermost one of the heat exchanger members, and at least partially overlapping the mounting member ( 13, 14 ).

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to heat exchangers, and more particularly to heat exchangers which are suitable for use as oil coolers in heavy vehicles. 
         [0002]    The disclosure particularly relates to so-called two (or more) flow integrated heat exchangers, i.e. heat exchangers where all fluid circuits are integrated in the plate bundle, and which thus do not need to be mounted in an enclosed cavity. However, the disclosure is also applicable to so-called single flow integrated type plate heat exchanges, where one of the fluid circuits is integrated in the plate bundle and the heat exchanger is essentially immersed in the other fluid circuit, which is typically enclosed by a cavity in which the heat exchanger is mounted. 
       BACKGROUND 
       [0003]    A basic principle for forming a heat exchanger is disclosed in e.g. WO 90/13394 A1 and WO 2004027334 A1. 
         [0004]    In a two (or more) flow integrated heat exchanger all fluid circuits are integrated in a plate bundle. Both the heat-emitting and cooling mediums are fed through inlet openings of the heat exchanger and flow through the plate bundle in separate channels. 
         [0005]    The stack of heat exchanger plates typically comprises mounting flanges, which may be connected to an outermost one of the heat exchanger plates, e.g. by being brazed thereto. 
         [0006]    In heat exchangers, it is desirable to have a high efficiency, such that more cooling can be achieved with a smaller and/or lighter heat exchanger. At the same time, a non-fragile construction is needed to withstand the forces resulting from thermal loads and pressure to which the heat exchanger is subjected when in use. Due to vibration or non-flatness of the heat exchanger, high stresses may occur in the heat exchanger plates, especially in the lower plate close to the mounting flanges providing fixation points for connecting the heat exchanger to a carrying structure. These stresses can for example lead to premature failure in the plate and leakage of the cooler. 
         [0007]    DE 19711258 A1 discloses a stacked disk oil cooler comprising several trough-shaped plates stacked and soldered together for forming adjacent hollow chambers. The lowest plate is mounted on a base plate and a reinforcing plate is arranged between the base plate and the lowest plate. The reinforcing plate is provided with a rim surrounding the edges of the lowest plate to increase the stability of the stacking disk oil cooler. 
         [0008]    When designing heat exchangers it is necessary to consider constructional aspects, strength aspects, mounting aspects as well as manufacturing aspects. Therefore, there is a need for further technical development aiming to provide increased freedom in the design of heat exchangers while maintaining or increasing the strength and efficiency of the heat exchanger. 
       SUMMARY 
       [0009]    It is a general object to provide a heat exchanger which alleviate or eliminate the drawbacks of the prior art. 
         [0010]    It is a particular object to provide a heat exchanger allowing freedom in design while at the same time increasing the strength and stability of the heat exchanger. 
         [0011]    It is a further object to provide a heat exchanger which can be easily manufactured. 
         [0012]    The invention is defined by the appended independent claims with embodiments being set forth in the dependent claims, the drawings and the description. 
         [0013]    According to a first aspect, there is provided a plate type heat exchanger for an oil cooler, comprising at least two heat exchanger members, each enclosing a respective first cavity, at least one inlet port, for feeding a medium to the first cavities and at least one output port for extracting the medium from the first cavities and at least one mounting member, which is attached to an outside of an outermost one, as seen in a stacking direction, of the heat exchanger members. A second cavity is formed between the at least two heat exchanger members, and a medium present in the second cavity is isolated from a medium present in the first cavities. A reinforcement plate is located on an inside of the outermost one of the heat exchanger members, as seen in the stacking direction, and at least partially overlapping the mounting member. 
         [0014]    The heat exchanger members may be substantially planar and the stacking direction may be perpendicular to a main plane of the heat exchanger members. 
         [0015]    Hence, the reinforcement plate is arranged inside the first cavity formed by the outermost one of the heat exchanger members. 
         [0016]    The overlap may be provided such that the projection of the reinforcement plate is entirely within the area of the mounting member, or vice versa. Preferably, at least 70%, at least 90% or at leat 95% of the reinforcement plate&#39;s projection on the mounting member is within the area of the mounting member. 
         [0017]    By providing a reinforcement plate on the inside of the heat exchanger member, it is possible to achieve a substantial strength improvement at the cost of a relatively small loss in heat transfer area. Moreover, this solution requires no or very little modification of the other parts of the heat exchanger. 
         [0018]    FEM simulations of the setup disclosed in  FIG. 2 a -2 b    herein indicate a stress decrease on the order of 50% for the outermost heat exchanger plate, which translates into a significant increase in durability of the heat exchanger. 
         [0019]    The mounting member may be fixedly connected to the outermost one of the heat exchanger members, as seen in a stacking direction, along an outside edge portion of the heat exchanger plate, and the reinforcement plate may be fixedly connected to the outermost one of the heat exchanger members substantially along an inside edge portion of the heat exchanger member. 
         [0020]    The inside edge portion may extends along its associated edge through a length which is about 30% to about 300% of a length of the outside edge portion, preferably about 50% to about 200% or about 50% to about 150%. 
         [0021]    The mounting member may be fixedly connected to the outermost one of the heat exchanger members from the edge portion and inwardly through a first length, as seen in a main plane of the heat exchanger plate, and the reinforcement plate may be fixedly connected to the outermost one of the heat exchanger members from the edge portion and inwardly through a second length, which is about 10%-300% of the first length (L 1 ), preferably about 20%-250%, or about 40%-200%. 
         [0022]    The reinforcement plate may present a substantially solid body having first and second base surfaces in a plane parallel with the heat exchanger members and a thickness perpendicular to said plane, which thickness is substantially equal to a height of the first cavity. 
         [0023]    The base surfaces may have a general shape of a section of an annulus, a segment of a circle, a crescent, or a polygon, such as a triangle, a rectangle, square, pentagon, etc. 
         [0024]    By “general shape” is understood, for example, that corners may be rounded, curve segments may have imperfections or deviations from a mathematically correct curve and/or that straight sections may have imperfections or deviations from the ideal straight line. 
         [0025]    The mounting member may comprise means for attaching the heat exchanger member to a carrier structure, such as a hole or recess for receiving a connecting element. 
         [0026]    The extension of the reinforcement plate along its associated edge may be less than an extension of the mounting member along the edge, but larger than a diameter of the hole. 
         [0027]    The heat exchanger member may be formed of a pair of stacked heat exchanger plates, which together define the first cavity. 
         [0028]    The heat exchanger plates may present a respective rim which extends substantially in a stacking direction and the heat exchanger plates may be stacked in a nesting manner. 
         [0029]    The outermost one of the heat exchanger members may comprise turbulating means received in the associated first cavity, wherein the turbulating means may (but need not) extend substantially throughout those parts of the first cavity that are not occupied by the reinforcement plate. The turbulating means typically also does not extend to those parts of the cavity where the ports are provided. 
         [0030]    The reinforcement plate may be made substantially out of metal or metal alloy. 
         [0031]    According to a second aspect, there is provided a method of manufacturing a heat exchanger, comprising providing a heat exchanger member enclosing a first cavity for receiving a first medium; and attaching a mounting member to an outside of the heat exchanger member. The method further comprises providing a reinforcement plate on an inside of the heat exchanger member, such that the reinforcement plate at least partially overlaps the mounting member. 
         [0032]    According to another aspect, there is provided a plate for forming a stacked plate type heat exchanger, comprising a base surface extending substantially in a main plane of the plate; and a rim extending from and along an outer edge of the plate and away from the base surface, substantially in a stacking direction. The rim presents a portion of increased wall thickness as compared to the remainder of the rim or as compared to at least a portion of the base surface. 
         [0033]    In this aspect, the plate may further comprise at least one mounting member, which is attached to an outside of the plate, and the portion of increased wall thickness may at least partially overlap the mounting member as seen along an edge of the plate. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1 a    is a schematic perspective view of a heat exchanger member for an oil cooling heat exchanger according to the prior art. 
           [0035]      FIG. 1 b    is a partial cross sectional view of the heat exchanger member of  FIG. 1   a.    
           [0036]      FIG. 1 c    is a schematic cross sectional view of a heat exchanger. 
           [0037]      FIG. 1 d    is a schematic cross sectional view of another version of a heat exchanger. 
           [0038]      FIG. 2 a    is a schematic perspective view of a heat exchanger member comprising a reinforcement plate. 
           [0039]      FIG. 2 b    is a partial cross sectional view of the heat exchanger member of  FIG. 2 a   . 
           [0040]      FIG. 3  is a partial top view of a heat exchanger member. 
           [0041]      FIGS. 4-6  schematically illustrate alternative heat exchanger plates. 
       
    
    
     DETAILED DESCRIPTION 
       [0042]      FIGS. 1 a  and 1 b    disclose a prior art heat exchanger plate  10 , which is arranged to constitute an outermost heat exchanger plate of a heat exchanger  1 ,  1 ′ ( FIGS. 1   c,    1   d ). The heat exchanger plate  10  comprises a base part  40  substantially extending in a base plane XY and a rim  41  extending from and along an edge of the base part  40  in a direction Z substantially perpendicular to the base plane XY. The base part  40  may present a plurality of dimples, ridges, grooves etc., which may be arranged to modify its flow properties and/or to provide support against adjacent heat exchanger plates. 
         [0043]    The heat exchanger plate  10  may present one or more openings  20 ,  21 ,  22 ,  23  forming, for example, ports for supplying or extracting cooling and/or heat emitting media. Openings may also be provided for assembly purposes, such as to allow a fastener and/or a fastening tool to reach wholly or partially through the heat exchanger. 
         [0044]    The heat exchanger plate  10  defines, together with a second heat exchanger plate  11 , a first cavity C 1 , adapted for receiving the cooling or heat emitting medium. In the cavity, there may be provided a turbulating device  12 . For clarity, only parts of the turbulator  12  are illustrated in the drawings. Such devices are known per se and provide the function of increasing the heat transfer capability of the heat exchanger as well as to provide some reinforcement of the heat exchanger. With respect to the turbulator  12  shown in  FIG. 1   a,  it is noted that this extends all the way around, i.e. encircles, the port  20 . 
         [0045]    The heat exchanger plate  10  may be provided with a mounting member  13 . The mounting member  13  may comprise a first mounting flange  131 , which may extend in a plane substantially parallel with the base plane XY of the heat exchanger plate  10 . This mounting member may comprise a hole, slit or recess for attachment to a structure that is to carry the heat exchanger. The mounting member  13  may optionally comprise one or more further flanges  131 , which may extend in a plane perpendicular to the base plane XY, such as in a plane YZ parallel with a short side edge of the heat exchanger plate  10  or in a plane XZ parallel with a long side edge of the heat exchanger plate  10 . 
         [0046]    The mounting member  13  may be attached to the heat exchanger plate  10 . For example, the mounting member  13  may be fixedly connected to the heat exchanger plate  10 , such as by brazing, welding or soldering. An attachment interface between the mounting member and the heat exchanger plate  10  may thus be provided on the outside of the base part  40 . This attachment interface may extend over a portion of the area of the base part, for example over less than 50% of the area of the base part  40 , less than 40%, less than 20%, less than 10% or less than 5%. 
         [0047]    Multiple mounting members  13  as described above may be provided, such as for example two, three, four or more mounting members. 
         [0048]    In a stack of a plurality of heat exchanger plates  10 , the mounting member  13  is typically provided on an outermost heat exchanger plate  10  as seen in the stacking direction Z. 
         [0049]    The heat exchanger plates may be fixedly connected to each other by e.g. brazing, in a per se known manner. 
         [0050]    When assembling a heat exchanger as disclosed in  FIGS. 1 a   - 1   b,  heat exchanger plates  10 ,  11 , turbulators and brazing material are stacked and optionally pressed together in the stacking direction while subjected to heating that causes the brazing material to melt and to join together the stack of plates  10 ,  11  and turbulators  12 . 
         [0051]    In  FIG. 1   c,  there is schematically illustrated a nested two-flow integrated heat exchanger, wherein pairs of adjacent heat exchanger plates  10 ,  11  together define heat exchanger members which enclose a respective cavity C 1 , C 2 . 
         [0052]    In  FIG. 1   d,  there is schematically illustrated a single flow integrated heat exchanger, wherein pairs of adjacent heat exchanger plates  10 ′,  11 ′ together form heat exchanger members, which each enclose a respective cavity C 1 , C 2 . 
         [0053]      FIGS. 2 a  and 2 b    disclose a heat exchanger plate which corresponds to that of  FIGS. 1 a -1 c    with the exception of the design of the turbulator  12 ′ and the presence of a reinforcement plate  30 . The reinforcement plate may be more rigid than the turbulator  12 ′. 
         [0054]    The reinforcement plate  30  may be provided in the form of a solid plate having a thickness in the stacking direction Z approximately corresponding to that of the turbulator  12 ′. The reinforcement plate  30 ,  31  may contact and be fixedly connected to the heat exchanger plates  10 ,  11  defining the cavity C 1  in which the reinforcement plate  30 ,  31  is located. The reinforcement plate  30  may have base surfaces parallel with the base plane XY. 
         [0055]    In the example illustrated in  FIGS. 2 a    and  2   b,  the reinforcement plate  30  is formed substantially as a section of an annulus, such that the space between the port hole  20  and the rim  41  is substantially filled by the reinforcement plate  30 . A corresponding portion of the turbulator  12 ′ is thus cut away to leave space for the reinforcement plate  30 . 
         [0056]    When assembling the heat exchanger, the reinforcement plate  30  may be brazed both to the first and second plates  10 ,  11 , such that a reinforcement of the rim area along which the reinforcement plate  30  extends is provided. 
         [0057]    The reinforcement plate  30  is positioned on the inside of the rim  41  in the vicinity of where the mounting member  13  is connected to the plate  10  on its outside, such that there is at least a partial overlap between the reinforcement plate  30  and the mounting member  13 . 
         [0058]    Thereby, the part of the plate  10  which is exposed to the highest stress is reinforced. The reinforcement plate  30  distributes the forces from the mounting member  13  to the adjacent exchanger plates, so that the outermost plate  10  and the first turbulator  12 ′ do not have to cope with the full load. In this case, the reinforcement plate  30  is placed in the one of the corners of the exchanger plate  10  that is connected to the mounting flange  13 . Since the corner naturally is an area of low heat-transfer, the performance loss is relatively insignificant. 
         [0059]      FIGS. 2 c -2 d    show heat exchangers corresponding to those of  FIGS. 1 c   ,  1   d,  respectively, but being provided with reinforcement plates  30  and mounting members  13 . 
         [0060]    Referring to  FIG. 3 , a reinforcement plate  30 ,  31  can be placed in other positions within the heat exchanger depending on the position of the mounting member  13 ,  14 . 
         [0061]    In  FIG. 3  a second reinforcement plate  31  is positioned on a long side edge of the heat exchanger plate  10 , such that it will at least partially overlap a second mounting member  14  which is arranged on the outside of the heat exchanger plate  10 , e.g. by brazing as described above. 
         [0062]    The extension of the reinforcement plate  30 ,  31  along the edge of the heat exchanger plate  10  may vary depending on the circumstances. The reinforcement plate  30 ,  31  may preferably be of a size where the extension along the edge is larger than a diameter of a connection hole  133 ,  134  in the mounting member  13 ,  14  and less than an extension of the mounting member  13 ,  14  along the edge. However, other sizes may also be appropriate. 
         [0063]    It is understood that depending on the circumstances, the reinforcement plate&#39;s  30 ,  31  extent along the edge may be smaller than, equal to or greater than that of the mounting member  13 ,  14 . 
         [0064]    The reinforcement plate&#39;s  30 ,  31  extent inwardly from the edge may, also dependent on the circumstances, be smaller than, equal to or greater than that of the mounting member  13 ,  14 . Where the reinforcement plate is positioned in along a long side, as illustrated in  FIG. 3 , its extent inwardly may typically be smaller than the extent inwardly of the mounting member  14 . 
         [0065]    The reinforcement plate  30 ,  31  may be made out of metal or an alloy such as carbon steel which makes it stable and produced to a low cost. However, other materials may also be considered depending on the existing conditions. 
         [0066]    The reinforcement plate  30 ,  31  may have one more recesses or through holes extending from its base surfaces, which may save weight. 
         [0067]    Moreover, the reinforcement plate may have a base surface having an arbitrary shape, such as a section of an annulus, a segment of a circle, a crescent, a triangle or a polygon. Further shapes are possible, for example where there are irregularities in the shape of the rim or where there are ports or other holes provided in the heat exchanger plate  10 , and where it is desirable to allow the reinforcement plate to follow the shape of the rim and/or of the ports or other holes. 
         [0068]    The problem elaborated upon above may be addressed in different ways. Instead of providing a reinforcement plate  30 ,  31 , there may be provided a base surface extending substantially in a main plane of the plate and a rim extending from and along an outer edge of the plate and away from the base surface, substantially in a stacking direction. The rim presents a portion of increased wall thickness as compared to the remainder of the rim or as compared to at least a portion of the base surface. 
         [0069]    With such a plate, at least one mounting flange may be attached to an outside of the plate such that the portion of increased wall thickness at least partially overlaps the mounting flange as seen along an edge of the plate. 
         [0070]    In  FIGS. 4 a    and  4   b,  there is illustrated a concept, wherein an outermost, as seen in the stacking direction Z, heat exchanger plate  100  is formed of an edge part  110  and a base part  120 , wherein the edge part  110  has a greater wall thickness than the base part  120 . The edge part may comprises a first portion  111  extending from the edge  101  and inwardly in the XY plane and a second portion  112  extending from the edge  101  and substantially upwardly in the stacking direction Z. The base part  120  may be connected to the edge part  110  at a distance from the edge  101 . The connection may be facilitated by a step  113  being provided in the edge part  110 , such that an inner surface of the edge part  110  will become flush with an inner surface of the base part  120 . The connection between the edge part  110  and the base part  120  may be provided by e.g. brazing as described above. 
         [0071]    The second portion  112  of the edge part  110  may have a height corresponding to the height of the rims  41  of the plates forming the heat exchanger. The first portion  111  of the edge part  110  may have an extent in inwardly from the edge  101  corresponding to about 50% to about 300% of a height of the second portion  120 . 
         [0072]    In  FIG. 5 , there is illustrated a concept, wherein a heat exchanger plate  10  is formed substantially as described with respect to  FIGS. 1 a   - 1   b,  but where a portion of the base surface  40  and the rim  41  are cut away and replaced by a reinforcement inset  200 . 
         [0073]    The reinforcement inset  200  may comprise a first portion  201  extending from the edge  101  and substantially upwardly in the stacking direction Z and a second portion  202  extending from the edge  101  and inwardly in the XY plane. The connection may be facilitated by a step  203  (not shown) being provided in the reinforcement inset  200 , such that an inner surface of the reinforcement inset  200  will become flush with an inner surface of the base surface  40 . The stepped portion may provide an overlap between the reinforcement inset  200  and the heat exchanger plate. This overlap may be greater at the base surface  40  than at the rim  41 . 
         [0074]    The connection between the reinforcement inset  200  and the base surface  40  may be provided by e.g. brazing as described above. 
         [0075]    The extent of the reinforcement inset  200  along the edge  101  may be determined according to the criteria discussed above with respect to  FIGS. 2 a   ,  2   b,    3 . In particular, the first portion  201  of the reinforcement inset may be of approximately the same size and shape as that part of the mounting member  13  which overlaps with the heat exchanger plate. 
         [0076]    The first portion  201  may have a height in the stacking direction Z corresponding to the height of the rim  41 . The second portion  202  may have an extent inwardly from the edge  101  of about 50% to about 500% of the height of the first portion  201 . 
         [0077]    Referring to  FIGS. 6 a    and  6   b,  there is illustrated a concept, wherein a reinforcement inset  300  is provided in a manner similar to that of  FIG. 5 , but where the reinforcement inset has very little extension in the base plane XY, such that essentially only a part of the rim  41  and optionally the radius connecting the rim to the base part  40  is cut away. The reinforcement inset  300  has a height in the stacking direction Z corresponding to the total height of the rim  41 . 
         [0078]    While the description above has been directed to a heat exchanger formed from a plurality of nested heat exchanger plates, it is understood that the concepts for increasing the strength of the outermost heat exchanger plate disclosed herein may be used also for other types of heat exchangers, including heat exchangers, wherein the heat exchanger members are formed of joined plates or flattened pipes.