Patent Publication Number: US-9845997-B2

Title: Heat exchanger

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a National Stage of International Application No. PCT/EP2012/076852, filed Dec. 21, 2012, which is based upon and claims the benefit of priority from prior German Patent Application No. 10 2011 090 176.0, filed Dec. 30, 2011, the entire contents of all of which are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The invention relates to a plate-type heat exchanger, in particular for motor vehicles, having a multiplicity of plate groups for forming first and second and third flow paths, wherein a space region for fourth flow paths is formed between adjacent plate groups. 
     PRIOR ART 
     Heat exchangers are provided in motor vehicles in large numbers and for a wide variety of purposes. Accordingly, in air-conditioning systems, evaporators are used for the purpose of cooling air, which flows through flow paths through the evaporator, by the evaporation of the refrigerant in flow paths in the evaporator, in order thereby to realize air conditioning and dehumidification in the vehicle interior. Flat-tube evaporators or plate-type evaporators have become known for this purpose. 
     In motor vehicles, the major trend in recent times has been to reduce the fuel consumption of a motor vehicle and the associated CO 2  emissions. This is achieved, in the case of motor vehicles with an internal combustion engine, inter alia by virtue of the internal combustion engine of the vehicle being shut down in temporary standstill situations, which arise for example as a result of the vehicle stopping at a traffic signal or in similar situations. When the vehicle is reactivated, by actuation of the accelerator pedal or the clutch pedal, for the purpose of driving away, the internal combustion engine is automatically reactivated. This technology is also referred to as the start-stop method. Such start-stop methods are already used in fuel-efficient motor vehicles. In the case of motor vehicle air-conditioning systems that are conventional on the market, with a refrigeration circuit based on the cold vapor process, the compressor of the refrigerant circuit is generally driven by way of a belt drive which is driven by the motor vehicle drive engine. When the engine is at a standstill, it is thus the case that, with the compressor drive at a standstill, the air-conditioning system can no longer be regarded as working so as to produce a refrigeration effect. When the engine is shut down in the start-stop mode, it is thus no longer possible for the air-conditioning system of the motor vehicle to operate and provide the refrigeration power for the cooling of the vehicle interior. As a consequence of this situation, the evaporator of the air-conditioning system warms up relatively quickly, and the air flowing through the evaporator is cooled only to a small extent or to an insufficient extent. This firstly has the effect that the vehicle interior temperature rises, adversely affecting the comfort of the vehicle occupants. 
     In the case of a motor vehicle air-conditioning system, not only the temperature reduction but also a dehumidification process takes place, because the air moisture present in the air is condensed at the evaporator and emerges from the vehicle through a condensate outlet. The air flowing through the evaporator is thus dehumidified and enters, having been dehumidified, into the vehicle interior. When a start-stop mode is active, this also has the effect that the dehumidification of the air entering into the vehicle interior can no longer be adequately ensured, such that the air moisture in the vehicle interior rises when the start-stop mode is active. This also leads to an increase in air moisture that is perceived by the vehicle occupants to be unpleasant and uncomfortable. 
     To prevent or slow these processes that lead to an increase in temperature and air humidity, the so-called accumulator-type evaporator has been developed which, aside from the actual evaporator function, also comprises a cold accumulator medium which extracts heat from, and continues to cool and dehumidify, the air that flows through the evaporator when the start-stop mode is active. 
     Said accumulator-type evaporators are known for example from DE 102006028017. Here, the accumulator-type evaporator disclosed in said document is composed of two separate heat exchanger blocks, the evaporator and the accumulator part, which are produced in different production processes and which are connected to one another only a short time before the brazing process, and which subsequently jointly undergo brazing to form a unit. Here, the main evaporator is composed of two flat-tube rows which are arranged one behind the other in the air direction, and the accumulator part is positioned downstream of said two flat-tube rows in the air direction. The accumulator part is in this case composed of double-tube rows in which two tubes are plugged one inside the other, wherein the refrigerant flows through the interior of the inner tube and the cold accumulator medium is arranged in the intermediate space between the outer tube and inner tube. The production process for this is cumbersome and expensive because numerous different parts have to be coordinated with one another, joined and calibrated in order to be able to produce a functional heat exchanger. In particular, the double tube with concealed tube inlets has proven to be relatively complex, the number of parts very high, with a simultaneously high number of different parts, and adhering to tolerances poses a risk to process capability owing to the multiplicity of components. This conversely entails increased risk of leakage, such that, aside from the part costs, there is also the risk of an increased rejection rate. 
     PRESENTATION OF THE INVENTION, PROBLEM, SOLUTION, ADVANTAGES 
     It is the object of the invention to provide a heat exchanger which is simple to produce and which entails lower costs than the heat exchangers known from the prior art, while simultaneously being of reduced complexity and resulting in a reduced rejection rate. 
     This is achieved by means of a heat exchanger having the features of claim  1 , according to which there is provided a plate-type heat exchanger, in particular for motor vehicles, having a multiplicity of plate pairs for forming first, second and third flow paths, wherein a space region for fourth flow paths is formed between adjacent plate pairs, and a plate pair is formed from at least one first plate and one second plate in order to form the first flow path and the second flow path between the first and the second plate, wherein the first and the second plate are assigned a first attachment plate and a second attachment plate, respectively, wherein the third flow path is formed between the first plate and the second attachment plate which is placed onto the first plate, and the first flow path is furthermore formed between the second plate and the first attachment plate which is placed onto the first plate, or the third flow path is formed between the first plate and the first attachment plate which is placed onto the first plate, and the first flow path is furthermore formed between the second plate and the second attachment plate which is placed onto the second plate. 
     It is advantageous here if the first plate and the second plate and the first and the second attachment plates have openings and/or cups as port and connecting regions, and have duct-forming structures such as embossments for forming at least one flow path between port regions. 
     It is also advantageous if the first plate and the second plate of the plate pair have, at two opposite end regions, in each case three port and connecting regions for the first, the second and the third flow path, wherein at least one duct-forming structure is provided between two opposite port regions in order to form the first or the second flow path. 
     It is furthermore advantageous if the first attachment plate and the second attachment plate of the plate pair have, at two opposite end regions, in each case two port and connecting regions for two of the first, second or third flow paths, wherein at least one duct-forming structure is provided between two opposite port regions in order to form the first or the third flow path. 
     It is also expedient if the first plate and the second plate have a region which can be provided with an attachment plate for the purpose of forming a duct-forming structure between in each case two port regions in order to form the first or the third flow path. 
     Here, it is also expedient if the duct-forming structures are embossed, in the form of a protruding duct, into the first plate and/or into the second plate and into the first attachment plate and into the second attachment plate. 
     It is furthermore expedient if the first attachment plate has a duct-forming structure between the port regions for the first flow path. 
     It is also advantageous if the second attachment plate has a duct-forming structure between the port regions for the second flow path. 
     In one development of the invention, it is expedient if the first attachment plate is formed in one piece with the first plate. 
     It is also advantageous if the second attachment plate is formed in one piece with the second plate. 
     It is furthermore advantageous if the first attachment plate is produced together with the first plate and the second attachment plate is produced together with the second plate, and said first attachment plate and second attachment plate can then in each case be placed onto a planar region of the first and second plate, respectively, by means of a bending process. 
     It is also advantageous if the first and/or the second attachment plate are/is formed separately from the first plate or from the second plate and can be placed onto a planar region of the first or second plate. 
     Further advantageous refinements are described in the following description of the figures and in the subclaims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be explained in more detail below on the basis of a least one exemplary embodiment and with reference to the drawings, in which: 
         FIG. 1  shows a first exemplary embodiment of a heat exchanger according to the invention, 
         FIG. 2  shows a view of an enlarged detail of  FIG. 1 , 
         FIG. 3  shows a view of a plate arrangement of a heat exchanger, 
         FIG. 4  shows a view of a plate arrangement of a heat exchanger, 
         FIG. 5  shows a view of a plate arrangement of a heat exchanger, 
         FIG. 6  shows a view of a plate arrangement of a heat exchanger, 
         FIG. 7  shows a view of a plate arrangement of a heat exchanger, 
         FIG. 8  shows a view of a plate arrangement of a heat exchanger in a detail view, 
         FIG. 9  shows a view of a plate arrangement of a heat exchanger in a detail view, 
         FIG. 10  shows a view of a plate arrangement of a heat exchanger in a sectional illustration, and 
         FIG. 11  shows a view of a plate arrangement of a heat exchanger in a sectional illustration. 
     
    
    
     PREFERRED EMBODIMENT OF THE INVENTION 
       FIG. 1  shows a heat exchanger  1  which is formed with a first, upper collector  2  and a lower second collector which are formed on opposite end regions of the heat exchanger and which extend in the transverse direction of the heat exchanger. Between the two collectors there is provided a block  4  which is composed of a network of plates, wherein the plates are joined together to form plate groups  5 , and space regions  6  are provided in each case between adjacent plate groups, which space regions are provided for a throughflow of air. The air flowing through said space regions is denoted by the arrow  101 . 
     As can be seen, the upper and the lower collector  2 ,  3  are formed from substantially three flow ducts which are formed by the three port connectors or port regions  7 ,  8  and  9 , wherein the port connectors in the plates of the plate pairs are preferably configured as openings and/or as cups, that is to say as embossments perpendicular to the plate plane. If two adjacent plate pairs now make contact, they make contact in the region of the cups, such that the cups, considered on their own, form a flow duct in the lateral direction of the heat exchanger. Between the collectors there are also provided flow ducts which extend between the port regions in the manner of cups. Here, the first, second and third flow ducts  10 ,  11 ,  12  are provided, wherein the flow ducts  10  are formed between the port regions  8 , the flow ducts  11  are formed between the port regions  7  and the flow ducts  12  are formed between the port regions  9 . 
       FIG. 2  shows a detail of the heat exchanger, in which it can be seen that the plate pairs have three adjacently arranged cups for connecting to the three flow ducts  10 ,  11 ,  12 , wherein the port  9  communicates with the flow duct  12  and is formed as an attachment plate. Here, the two ports  7 ,  9  are formed by the attachment plate  13 , which is placed onto the plate  14  with the port  8 . 
       FIG. 3  shows the plate pair  20 , which is formed in two parts and is composed of a first plate  21  and of a second plate  22 . Here, the plate  21  is composed of a main plate  23  and an attachment plate  24 , wherein the plate  22  is composed of a main plate  25  and an attachment plate  26 . As can be seen, the main plate  23  has, at the two opposite end regions, in each case three fluid ports  27 ,  28  and  29 , wherein only the port  29  is formed as a protruding cup, and a flow duct  42  is embossed into the main plate  23  only between said two cups  29 . No fluid ducts are embossed into the main plate  23  between the openings  27  and  28  respectively. In turn, the attachment plate that is connected to the main plate has, at both the upper and lower end regions, two ports which are embossed as cups and which are of protruding form, wherein the cups  30  are formed into the attachment plate without having a fluid duct formed between them. The ports  31 , which are embossed in the manner of cups, have a fluid duct which is denoted by  32  and which, in principle, covers the entire width of the attachment plate, wherein a narrowing of the fluid duct is provided in the region close to the port in order that said fluid duct does not collide with the port  30 . The plate  22  is of similar form, wherein the plate  22  in turn has openings  33 ,  34  and  35  at both the upper and lower end regions, wherein it is in turn also the case here that only the openings  35  are formed or embossed in the manner of cups and a fluid duct  36  is embossed into the plate between said cup-like port regions. The openings or ports  33  and  34  are not embossed as cups, and also do not have a fluid-duct-like connection between them. 
     Adjacent to the main plate  25  there is in turn provided an attachment plate  26  which is connected to the main plate, wherein the attachment plate  26  in turn has port regions  37  and  38  at its two upper and lower end regions, wherein said two port regions  37  and  38  are in turn embossed in the manner of cups, wherein, in the exemplary embodiment of said plate, the cups  37  are connected to a fluid duct  39 , wherein the embossments  38  do not communicate with the fluid duct  39 . 
     To produce a plate pair, the two plate main regions  23  and  25  are then placed onto one another such that the openings  29  are in alignment with the openings  33 , the openings  28  are in alignment with the openings  34 , and the openings  27  are in alignment with the openings  35 . In this way, the planar region  40  laterally covers the fluid duct  42 , and the planar region  41  laterally covers the fluid duct  36 . The attachment regions  24  are subsequently folded over onto the region  40 , and the attachment plate  26  is folded over onto the region  41 , such that a total of four separate fluid ducts are formed, wherein the fluid duct  42  is covered by the surface region  40  and the fluid duct  32  is placed thereon. Since the cups  30  and  31 , and the openings  29  and  28 , respectively, are not in fluid communication with one another, it is correspondingly the case that two adjacent flow ducts  42  and  32  are formed which do not communicate with one another. At the same time, the fluid duct  36  is formed by virtue of its being covered by the surface region  41 , and the fluid duct  39  is likewise covered by the surface  41 , wherein in this case, however, the two cups  35  and  37  communicate with one another via the opening  27 , such that the fluid ducts  36  and  39  are connected fluidically and in parallel. The port  38  communicates, by way of the opening  28 , with the opening  34  and with the cup  31 , and is thus connected to the fluid duct  32 . 
     Overall,  FIG. 3  thus shows the form of a plate pair in which two plates are used, with main plates and attachment plates, wherein, by virtue of the main plates being placed onto one another and the attachment plates being respectively folded over onto a planar region of the adjacent main plate, a total of four flow ducts are formed, of which, however, two are connected fluidically in parallel, such that a total of three fluid ducts are provided to which a feed can be provided through the three port regions at the end regions of the plate pairs. 
       FIGS. 4 to 6  show this process again in schematic form.  FIG. 4  shows that, in the two plates  50 ,  51 , there are provided three fluid or refrigerant ducts which are denoted by  52 ,  53  and  54 , wherein a further duct or cold accumulator duct is also provided, this being denoted by  55 . Four ducts are thus shown. By virtue of the main plates being placed onto one another, in this regard see the arrow  56  in  FIG. 4  and  FIG. 5 , in which the two main plates have already been placed onto one another, the respective attachment plate is subsequently placed onto the planar surface of the adjacent main plate by virtue of the attachment plates being folded over. This is indicated by the arrows  57 ,  58  in  FIG. 5 . It can be seen in  FIG. 6  that said attachment plates have already been folded over and form a plate pair. 
       FIG. 6  shows two plate pairs, each from a different side, wherein it can be seen that the plate  59  has a fluid duct  62  which communicates with a large port opening  61 , and the fluid duct  62  is thus a refrigerant fluid duct in the event that refrigerant flows through said port  61 . The port  63  is likewise connected to a fluid duct, though this cannot be seen in the view of this side. It can also be seen that the ports  64  are fluidically connected to the fluid duct  65 . The opposite side of the plate  60  shows that the ports  61  are connected to the fluid duct  66 , the ports  63  are connected to the fluid duct  67 , and the ports  64  are not connected to a fluid duct that can be seen on this side. 
       FIG. 7  shows an alternative exemplary embodiment in this regard, in which the structure of the plates as per  FIG. 3  is substantially maintained, wherein the main difference between the exemplary embodiments of  FIGS. 3 and 7  lies in the interchanged arrangement of the fluid ducts in the main plates in relation to the attachment plate. Accordingly, it can be seen that  FIG. 7  shows a plate  70  which has a main plate  71  and an attachment plate  72 . The attachment plate  72  corresponds to the attachment plate  24  as per  FIG. 3 , wherein the main plate  71  has been modified in relation to the main plate  23  such that the fluid duct  73  is now arranged not between the openings  29  adjacent to the attachment plate but rather between the ports  74  which are arranged at that end of the plate which is remote from the attachment plate, and furthermore, the cups  74  are embossed in the opposite direction to the cups  75  of the attachment plate. 
     The same substantially applies to the plate  76 , which has a main plate  77  and an attachment plate  78 , wherein it is in turn also the case here that the main plate  77  has a fluid duct  79  between ports  80 , and the openings  81  arranged adjacent to the remote end of the plate are not provided with a fluid duct. It can also be seen that the cups of the ports of the attachment plate are in turn embossed in a different direction than the cups  80  of the main plate  77 . It can also be seen that the attachment plate  78  only has an embossment at its respective ends and has the embossment. 
     When the two plates  70  and  76  are mounted on one another, that is to say the main plates are placed onto one another, and the attachment plates are subsequently folded over, said attachment plates are placed not onto the adjacent plate but rather onto the plate to which they are connected. This can also be seen in  FIGS. 8 and 9 . 
       FIG. 8  shows the arrangement of the plates  70  and  76  such that the two main plates  71  and  77  have been placed onto one another. The attachment plate  72  is subsequently placed onto the planar region  83  of the plate  71 , wherein, subsequently, the attachment plate  78   a  is placed onto the planar region (not visible) of the plate  76 . 
       FIG. 9  then shows the plates, with main plates and attachment plates, which are connected to one another, wherein it can be seen that the attachment plate  72  is connected to the main plate  71 . Between  FIG. 8  and  FIG. 7 , a difference can also be seen with regard to the port  84 . Said port was not provided in  FIG. 7 , because, in said figure, the port  85  for the fluid duct  86  was configured with a doubled depth, such that the port  84  was superfluous and it was nevertheless possible for a functional connection of the ports to be realized. If the port  86  is now provided with the same depth as the ports  87  and  88 , then it is necessary for the port  84  to be formed with the same depth as the port  86 . This configuration uses the advantage that all of the cups of the ports  84 ,  86 ,  87  and  88  have the same depth.  FIG. 7  is an exemplary embodiment in which the cups  85  have a depth twice that of the other cups, such that the cup  84  provided in  FIG. 8  can be omitted. 
       FIGS. 10 and 11  show a section through a number of plate pairs  90 ,  91  and  92 , wherein the plate pairs each form four separate flow ducts which are produced by virtue of the individual plates and attachment plates being placed onto one another. 
       FIG. 11  shows a detail from  FIG. 10 , wherein the four different flow ducts  93 ,  94 ,  95  and  96  formed by the respective plates and attachment plates can be seen. Accordingly, the partition  97  and the outer wall  98  are formed by one plate, specifically by the plate  71  in  FIG. 7 . Furthermore, the partition  99  and the side wall  100  are formed by one plate, specifically the plate  77  in  FIG. 7 . 
     In the present exemplary embodiment of  FIG. 7  with the elongated rim hole  85  of the plate  72 , it can be seen that the cutout  89  in the plate  76  is larger than the diameter of the rim hole  85 , such that, when two plate groups  70 ,  71  and  76 ,  77  are brazed onto one another, the rim hole  85  comes into contact not with the plate  76  but rather with the plate  71  onto which the plate  72  is brazed from the other side. It is achieved in this way that, in the event of leakage between the brazed plates in the region of the rim hole  85 , said leakage occurs only between the outer chamber and the duct between the plates  70  and  71 , wherein the other ducts are thereby not involved or compromised. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Heat exchanger 
           2  Collector 
           3  Collector 
           4  Block 
           5  Plate group 
           6  Space region 
           7  Port region 
           8  Port region 
           9  Port region 
           10  Flow duct 
           11  Flow duct 
           12  Flow duct 
           13  Attachment plate 
           14  Plate 
           20  Plate pair 
           21  Plate 
           22  Plate 
           23  Main plate 
           24  Attachment plate 
           25  Main plate 
           26  Attachment plate 
           27  Fluid port 
           28  Fluid port 
           29  Fluid port 
           30  Port, cup 
           31  Port 
           32  Fluid duct 
           33  Opening 
           34  Opening 
           35  Opening 
           36  Fluid duct 
           37  Port region, cup 
           38  Port region, cup 
           39  Fluid duct 
           40  Planar region 
           41  Region 
           42  Flow duct 
           50  Plate 
           51  Plate 
           52  Fluid or refrigerant duct 
           53  Fluid or refrigerant duct 
           54  Fluid or refrigerant duct 
           55  Fluid or cold accumulator duct 
           56  Arrow 
           57  Arrow 
           58  Arrow 
           59  Plate 
           60  Plate 
           61  Port 
           62  Fluid duct 
           63  Port 
           64  Port 
           65  Fluid duct 
           66  Fluid duct 
           67  Fluid duct 
           70  Plate 
           71  Main plate 
           72  Attachment plate 
           73  Fluid duct 
           74  Port 
           75  Port 
           76  Plate 
           77  Main plate 
           78  Attachment plate 
           78   a  Attachment plate 
           79  Fluid duct 
           80  Port 
           81  Opening 
           82  Port 
           83  Region 
           84  Port, cup 
           85  Port, cup 
           86  Fluid duct 
           87  Port 
           88  Port 
           89  Cutout 
           90  Plate pair 
           91  Plate pair 
           92  Plate pair 
           93  Flow duct 
           94  Flow duct 
           95  Flow duct 
           96  Flow duct 
           97  Partition 
           98  Outer wall 
           99  Partition 
           100  Side wall 
           101  Air direction