Patent Publication Number: US-7219511-B2

Title: Evaporator having heat exchanging parts juxtaposed

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an evaporator having two heat exchanging parts juxtaposed in the flowing direction of wind passing through the evaporator. 
   2. Description of the Related Art 
   An evaporator having two heat exchanging parts juxtaposed in the flowing direction of wind is disclosed in Japanese Patent Application Laid-open Nos. 6-74679, 10-238896 and 2000-105091. 
   The inventor is developing an evaporator shown in  FIG. 1 . The evaporator  100  includes two heat exchanging parts juxtaposed on upwind and downwind sides in the flowing direction of wind, respectively. 
   The “downwind-side” heat exchanging part  110  has an upper tank  111 , a lower tank  112  and a plurality of heat exchanging passages between the tanks  111  and  112 . These heat exchanging passages are also communicated with the tanks  111 ,  112 . Similarly, the “upwind-side” heat exchanging part  120  has an upper tank  121 , a lower tank  122  and a plurality of heat exchanging passages between the tanks  121  and  122 . As well, these heat exchanging passages are communicated with the tanks  121 ,  122 . 
   The “downwind-side” heat exchanging part  110  and the “upwind-side” heat exchanging part  120  are arranged so as to overlap each other back and forth in the flowing direction of wind. 
   In the downwind-side heat exchanging part  110 , the upper tank  111  is provided, on its right side, with an evaporator inlet  107 . The upper tank  111  is partitioned to a first upper tank part  111   a  and a second upper tank part  11   b  by a partition  114 , while the lower tank  112  is partitioned to a first lower tank part  112   a  and a second lower tank part  112   b  by a partition  115 . The laminated heat exchanging passages are divided into a first path  110   a , a second path  110   b  and a third path  110   c  in order from the right. Consequently, coolant introduced into the downwind-side heat exchanging part  110  via the evaporator inlet  107  flows through the first upper tank part  111   a , the first path  110   a , the first lower tank part  112   a , the second path  110   b , the second upper tank part  111   b , the third path  110   c  and the second lower tank part  112   b , in this order. Then, the coolant is introduced from the most downstream side (i.e. the second lower tank part  112   b ) of the downwind-side heat exchanging part  110  into the most upstream side (i.e. the first lower tank part  122   a ) of the upwind-side heat exchanging part  120  through a communication passage  109 . 
   In the upwind-side heat exchanging part  120 , the lower tank  122  is partitioned to a first lower tank part  122   a  and a second lower tank part  122   b  by a partition  124 , while the upper tank  121  is partitioned to a first upper tank part  121   a  and a second upper tank part  121   b  by a partition  125 . The upper tank  121  is provided, on its right side, with an evaporator outlet  108 . Thus, the laminated heat exchanging passages are divided into a first path  120   a , a second path  120   b  and a third path  120   c  in order from the right. Consequently, the coolant introduced into the upwind-side heat exchanging part  120  via the communication passage  109  flows through the first lower tank part  122   a , the first path  120   a , the first upper tank part  121   a , the second path  120   b , the second lower tank part  122   b , the third path  120   c  and the second upper tank part  121   b , in this order. Then, the coolant is discharged from the evaporator  100  through the evaporator outlet  108  on the right side of the second upper tank part  121   b  as the most downstream part of the upwind-side heat exchanging part  120 . 
   Here noted, the paths overlapping on the upwind and downwind sides, for example, the first path  110   a  of the downwind-side heat exchanging part  110  and the third path  120   c  of the upwind-side heat exchanging part  120  have the number of heat exchanging passages equal to each other and the flowing direction of coolant opposite to each other, including the flowing of coolant in the tank parts. 
   With the above-mentioned structure, the liquid-phase coolant L in the heat exchanging parts  110 ,  120  is distributed as shown in  FIG. 2A . Consequently, the distribution of liquid-phase coolant L in the whole evaporator is shown in  FIG. 2B . In  FIG. 2B , since the wind cannot be cooled down sufficiently in areas where the liquid-phase coolant L does not flow, in other words, only gas-phase coolant G does flow, the “blowout” temperature of the coolant is elevated disadvantageously. 
   SUMMARY OF THE INVENTION 
   In the above-mentioned situation, it is an object of the present invention to provide an evaporator including upwind-side and downwind-side opposing paths each having the flowing directions of coolant opposite to each other, the evaporator enabling a reduction of an area causing a rise in “blowout” temperature of the liquid-phase coolant due to its short supply. 
   In order to attain the above object, an aspect of the present invention provides an evaporator comprising: heat exchanging parts juxtaposed on both upwind and downwind sides in a flowing direction of wind passing through the evaporator, the heat exchanging parts each including: a plurality of heat exchanging passages each formed to extend vertically and arranged so as to be laminated on each other along a horizontal direction of the evaporator, for performing heat exchange between a coolant flowing inside the heat exchanging passages and air flowing outside the heat exchanging passages; a plurality of tanks communicatively connected to respective upper and lower ends of the heat exchanging passages and each arranged so as to extend horizontally; and a plurality of partitions arranged in the tanks to divide the heat exchanging parts into a plurality of paths so that one of the heat exchanging parts has a meandering number of the heat exchanging passages equal to the meandering number of the heat exchanging passages in the other of the heat exchanging parts, the paths including upwind-side paths arranged on the upwind side in the flowing direction of wind and downwind-side paths arranged on the downwind side so as to each oppose to the upwind-side paths respectively, wherein a flowing direction of the coolant flowing in the upwind-side paths is opposite to a flowing direction of the coolant flowing in the downwind-side path opposing the upwind-side paths, and wherein the number of heat exchanging passages in the paths where the coolant rises is smaller than the number of heat exchanging passages in the paths where the coolant downs. 
   Since the number of heat exchanging passages in the paths where the coolant rises is smaller than the number of heat exchanging passages in the paths where the coolant downs, it becomes possible to increase the quantity of coolant flowing in the former paths that are apt to be short in supplying the coolant. As the result, it is possible to reduce an area causing a rise in “blowout” temperature of the coolant due to the short supply. 
   According to a preferred embodiment of the present invention, the coolant first flows in either one of the heat exchanging parts on the upwind and downwind sides in the flowing direction of wind and subsequently flows in the other of the heat exchanging parts. 
   Since the coolant flows in the heat exchanging parts in order, the coolant can be cooled down sufficiently. 
   The evaporator may further comprises a side plate attached to an outermost side of the heat exchanging passages in a laminating direction thereof to reinforce the evaporator, wherein the side plate has a communication passage integrally formed therein to communicate, in a flowing direction of the coolant, a most downstream part of the heat exchanging part on the upstream side in the flowing direction of the coolant with a most upstream part of the heat exchanging part on the downstream side in the flowing direction of the coolant. 
   Since the communication passage is formed integrally with the side plate, there is no need to prepare an exclusive member for the communication passage. As the result, it is possible to save the manufacturing cost of the evaporator. 
   These and other objects and features of the present invention will become more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view showing an example of an evaporator; 
       FIGS. 2A and 2B  are schematic views showing the distribution of liquid-phase coolant in the evaporator of  FIG. 1 ; 
       FIG. 3  is a front view of an evaporator in accordance with an embodiment of the present invention, also viewed from its upwind side; 
       FIG. 4  is a top view of the evaporator of  FIG. 3   
       FIG. 5  is a side view of the evaporator of  FIG. 3 , on the right side in the width direction of the evaporator; 
       FIG. 6  is a side view of the evaporator of  FIG. 3 , on the left side in the width direction of the evaporator; 
       FIGS. 7A to 7D  are various views of a side plate of the evaporator of  FIG. 3 , on the left side in the width direction of the evaporator,  FIG. 7A  is a plan view of the side plate,  FIG. 7B  a view of the side plate viewed in the direction of arrow B of  FIG. 7A ,  FIG. 7C  a view of the side plate viewed in the direction of arrow C of  FIG. 7A  and  FIG. 7D  a view of the side plate viewed in the direction of arrow D of  FIG. 7A ; 
       FIGS. 8A to 8D  are various views of another side plate of the evaporator of  FIG. 3 , on the right side in the width direction of the evaporator:  FIG. 8A  is a plan view of the side plate,  FIG. 8B  a view of the side plate viewed in the direction of arrow B of  FIG. 8A ,  FIG. 8C  a view of the side plate viewed in the direction of arrow C of  FIG. 8A  and  FIG. 8D  a view of the side plate viewed in the direction of arrow D of  FIG. 8A ; 
       FIGS. 9A to 9D  are various views of a first metal sheet forming a tube of the evaporator of  FIG. 3 :  FIG. 9A  is a plan view of the first metal sheet,  FIG. 9B  a view of the first metal sheet viewed in the direction of arrow B of  FIG. 9A ,  FIG. 9C  a view of the first metal sheet viewed in the direction of arrow C of  FIG. 9A  and  FIG. 9D  a view of the first metal sheet viewed in the direction of arrow D of  FIG. 9A ; 
       FIGS. 10A to 10D  are various views of a second metal sheet forming a tube of the evaporator of  FIG. 3 :  FIG. 10A  is a plan view of the second metal sheet,  FIG. 10B  a view of the second metal sheet viewed in the direction of arrow B of  FIG. 10A ,  FIG. 10C  a view of the second metal sheet viewed in the direction of arrow C of  FIG. 10A  and  FIG. 10D  a view of the second metal sheet viewed in the direction of arrow D of  FIG. 10A ; 
       FIG. 11A  is an exploded perspective view of the tube, showing its lamination structure and  FIG. 11B  is a perspective view of the tube in its assembled state; 
       FIG. 12A  is a sectional view of one pair of metal sheets before being caulked and  FIG. 12B  is a sectional view of the metal sheets after being caulked; 
       FIG. 13  is a sectional view of a tank part of the tubes, showing its lamination structure; 
       FIG. 14  is a schematic view of the evaporation, showing the flowing of coolant therein; 
       FIG. 15A  is a schematic view showing the distribution of liquid-phase coolant in two evaporator parts; and 
       FIG. 15B  is a schematic view showing the distribution of liquid-phase coolant in the evaporator parts in combination. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the accompanying drawings, an embodiment of the present invention will be described below. 
     FIGS. 3 to 15B  show an embodiment of the present invention. An evaporator  1  of this embodiment can be used for an evaporator that is interposed in a refrigeration cycle of an automotive air conditioner. The evaporator  1  is positioned in an air-conditioner casing inside an instrument panel of a vehicle. The evaporator  1  carries out heat exchanging between coolant flowing in the air-conditioner casing and air passing through the outside of the air-conditioner casing. In the evaporator  1 , the coolant is evaporated to cool down the air. 
   First of all, the whole structure of the evaporator  1  will be described with reference to  FIG. 14 , in brief. 
   The evaporator  1  includes two heat exchanging parts  10 ,  20  juxtaposed on upwind and downwind sides, respectively. 
   The “downwind-side” heat exchanging part  10  has an upper tank  11 , a lower tank  12  and a plurality of heat exchanging passages between the upper tank  11  and the lower tank  12 . These heat exchanging passages are also communicated with the tanks  11 ,  12 . Similarly, the “upwind-side” heat exchanging part  20  has an upper tank  21 , a lower tank  22  and a plurality of heat exchanging passages between the upper tank  21  and the lower tank  22 . As well, these heat exchanging passages are communicated with the tanks  21 ,  22 . 
   In the downwind-side heat exchanging part  10 , the upper tank  11  is partitioned to a first upper tank part  11   a  and a second upper tank part  11   b  by a partition  14 , while the lower tank  12  is partitioned to a first lower tank part  12   a  and a second lower tank part  12   b  by a partition  15 . The upper tank  11  is provided, on its right side, with an evaporator inlet  7 . The heat exchanging passages stacked in multistage are divided into a first path  10   a , a second path  10   b  and a third path  10   c  in order from the right. Consequently, the coolant introduced into the downwind-side heat exchanging part  10  via the evaporator inlet  7  flows through the first upper tank part  11   a , the first path  10   a , the first lower tank part  12   a , the second path  10   b , the second upper tank part  11   b , the third path  10   c  and the second lower tank part  12   b , in this order. Then, the coolant is introduced from the most downstream side (i.e. the second lower tank part  12   b ) of the downwind-side heat exchanging part  10  into the most upstream side (i.e. the first lower tank part  22   a ) of the upwind-side heat exchanging part  20  through a communication passage  9 . 
   In the upwind-side heat exchanging part  20 , the lower tank  22  is partitioned to a first lower tank part  22   a  and a second lower tank part  22   b  by a partition  24 , while the upper tank  21  is partitioned to a first upper tank part  21   a  and a second upper tank part  21   b  by a partition  25 . The upper tank  21  is provided, on its right side, with an evaporator outlet  8 . The heat exchanging passages stacked in multistage are divided into a first path  20   a , a second path  20   b  and a third path  20   c  in order from the right. Consequently, the coolant introduced into the upwind-side heat exchanging part  20  via the communication passage  9  flows through the first lower tank part  22   a , the first path  20   a , the first upper tank part  21   a , the second path  20   b , the second lower tank part  22   b , the third path  20   c  and the second upper tank part  21   b , in this order. Then, the coolant is discharged from the evaporator  1  through the evaporator outlet  8  on the right side of the second upper tank part  21   b  as the most downstream part of the upwind-side heat exchanging part  20  on the outlet-side of the coolant&#39;s flow. 
   In the evaporator  1 , the heat exchanging parts  10 ,  20  are each divided into the plural paths (e.g. three paths each in the shown example, that is, the paths  10   a ,  10   b ,  10   c  and the paths  20   a ,  20   b ,  20   c ) so as to have the same meandering number in each of the parts  10 ,  20 . Further, in the opposing paths overlapped on both “upwind” and “downwind” sides (for example, the first path  10   a  of the part  10  and the third path  20   c  of the part  20 ), the flowing directions of the coolant therein are opposite to each other, vertically and horizontally, including the coolant&#39;s flows in the tank parts on the upstream and downstream sides of the opposing paths. 
   As shown in  FIGS. 3 to 6 , the evaporator  1  of this embodiment includes a plurality of tubes  30  stacked on each other and a plurality of outer fins  33  each interposed between the adjoining tubes  30 . Each of the tubes  30  includes a pair of metal sheets  40  ( 40 A,  40 B). The tube  30  is produced by laying the reversed metal sheet  40 A on the metal sheet  40 B and further welding them to each other. In order to reinforce the strength of the evaporator  1 , side plates  34 ,  35  are arranged on both “outermost” sides of the evaporator  1  in the laminating direction of the tubes  30 , providing it with a designated configuration. 
   As shown in  FIGS. 5 ,  8 A,  8 B,  8 C and  8 D, the side plate  34  has a communication port  34   a  formed in communication with the most upstream part (the first upper tank part  11   a ) of the heat exchanging part  10  and another communication port  34   b  formed in communication with the most downstream part (the second upper tank part  21   a ) of the heat exchanging part  20 . A piping connector  36  forming the inlet  7  and the outlet  8  of the evaporator  1  is attached to the communication ports  34   a ,  34   b . The other side plate  35  (see  FIGS. 6 ,  7 A,  7 B,  7 C and  7 D) has a communication passage  9  formed to communicate the most downstream part of the part  10  (i.e. the second lower tank part  12   b ) with the most upstream part of the part  20  (i.e. the first lower tank part  22   a ). Noted that reference numerals  35   b  denote reinforcing protrusions formed on the side plate  35 , while reference numeral  37  denotes a reinforcing plate arranged between the side plate  34  and the piping connector  36 . 
   The constitution of the tube  30  will be described below. 
     FIG. 11A  is a perspective view of the tube  30 , showing its exploded state.  FIG. 11B  is a perspective view of the tube  30  in its assembled state.  FIGS. 9A to 9D  show the metal sheet  40  ( 40 A or  40 B) forming the tube  30 . Noted that the metal sheet  40 A has a configuration identical to that of the metal sheet  40 B. As shown in  FIG. 11A , the posture of the metal sheet  40 B can be obtained by turning over the metal sheet  40 A about a center axis X for inversion, and vice versa. 
   The tube  30  is provided, therein, with heat exchanging passages  31 ,  31  for heat exchange between the coolant flowing in the passages  31 ,  31  and air flowing outside the tube  30 . The heat exchanging passages  31 ,  31  comprise one heat exchanging passage  31  for the “downwind-side” heat exchanging part and another heat exchanging passage  31  for the “upwind-side” heat exchanging part. On both ends of the heat exchanging passage  31  in the longitudinal direction of the tube  30 , cylindrical tank parts  32 ,  32  are formed so as to project upwardly. That is, each metal sheet  40 A ( 40 B) forming the tube  30  includes two concave “heat-exchanging passage” parts  41 ,  42  extending along the longitudinal direction of the tube  30  and four tank parts  43 ,  44 ,  45 ,  46  ( 32 ,  32 ). 
   The metal sheet  40  ( 40 A or  40 B) has a plurality of projecting pieces  47  and recesses  48  formed in the outer periphery of the sheet  40 . Each of the projecting pieces  47  is positioned in line-symmetry with the notch  48  about the above axis X. Consequently, when opposing the interior side of the metal sheet  40 A to the interior side of the metal sheet  40 B, the projecting pieces  47  and the recesses  48  of the former sheet  40 A oppose the recesses  48  and the projecting pieces  47  of the latter sheet  40 B, respectively. Then, when confronting the former sheet  40 A against the latter sheet  40 B while maintaining the above postures of the sheets  40 A,  40 B, the projecting pieces  47  are engaged in the recesses  48  respectively, thereby effecting the mutual positioning of the sheets  40 A,  40 B. 
   Noted that two inner fins  61 ,  61  are disposed between the metal sheet  40 A and the metal sheet  40 B before the engagement of projecting pieces  47  with the recesses  48 . Then, as shown in  FIGS. 12A and 12B , the metal sheets  40 A,  40 B are caulked by folding the projecting pieces  47  inwardly, realizing the tube  30  in a temporary fixed condition. 
   It is noted in the shown embodiment that the above top-and-back inversion axis X is identical to a sheet&#39;s center line extending along the direction perpendicular to the longitudinal direction of the metal sheet  40 , namely, a center line for dividing the metal sheet  40  into two equal parts in the longitudinal direction of the sheet  40 . 
   In the manufacturing procedure of the evaporator  1  (see  FIGS. 11A and 11B ), a plurality of tubes  30  in the above temporary fixed condition are laminated on each other, so that the evaporator shown in  FIGS. 3 to 6  is assembled temporarily. Thereafter, by a not-shown jig, this assembly is transferred to a welding furnace. In connection, it is noted that  FIGS. 11A and 11B  do not illustrate the outer fin  33  for convenience of understanding. 
   According to the above-mentioned manufacturing process, the possibility of positioning the adjoining tubes  30  would allow the laminating operation of the tubes  30  to be automatized, whereby the manufacturing cost can be saved. In other words, the possibility of positioning the metal sheets  40 A,  40 B in their back-to-back condition would allow the laminating operation of the tubes  30  to be automatized to reduce the manufacturing cost of the evaporator  1 . In order to offer such advantages in the evaporator  1 , either one of the tank parts  43 ,  44  ( 45 ,  46 ) on both sides of one concave part  41  is provided with locating parts (locating means). In the embodiment shown in  FIGS. 9A and 9B , the tank part  43  has an engagement projection  49  formed on the periphery of its opening end  43   a , as the locating means. The tank part  46  has another engagement projection  49  formed on the periphery of its opening end  46   a  as well. 
   In assembling, the engagement projections  49  of the tank parts  43 ,  46  of one tube  30  are engaged in the opening ends  44   a ,  45   a  of the tank parts  44 ,  45  of the other tube  30 . The engagements allow the adjoining tubes  30  in lamination to be positioned to each other. 
   In addition to the metal sheets  40 , the evaporator  1  further includes a plurality of second metal sheets  50  each shown in  FIGS. 10A to 10D . The second metal sheet  50  differs from the first metal sheet  40  in that an partition  51  is formed at one of the four tank parts  43 ,  44 ,  45  and  46 . This integral-molding partition  51  constitutes each of the afore-mentioned partitions  14 ,  15 ,  24 ,  25  (see  FIG. 14 ) for dividing the heat exchanging parts  10 ,  20  into the paths  10   a ,  10   b ,  10   c ,  20   a ,  20   b  and  20   c . Depending on the position of the second metal sheet  50  that is interposed in the lamination of the tubes  30 , the compartmentalization of these paths  10   a ,  10   b ,  10   c ,  20   a ,  20   b  and  20   c  is determined in the heat exchanging parts  10 ,  20 . Note, in  FIGS. 3 and 4 , reference numerals  50 A,  50 B,  50 C,  50 D denote the same metal sheets  50  although some of them are inverted inside and out in the arrangement of the heat exchanger. 
   The feature of the embodiment of the present invention resides in the compartmentalization of these paths due to the arrangement of the second metal sheets  50 . As shown in  FIGS. 4 ,  14 ,  15 , the partition  25  is arranged on right side of the partition  14 , and the partition  24  is arranged on left side of the partition  15 . As shown in these figures, it is established that the number of heat exchanging passages in the paths  10   b ,  20   a  and  20   c  where the coolant rises is smaller than the number of heat exchanging passages in the paths  10   a ,  10   c  and  20   b  where the coolant downs. As the result, the dimensions of the paths  10   b ,  20   a  and  20   c  along the horizontal direction of the evaporator  1  become smaller than those of the paths  10   a ,  10   c  and  20   b , respectively. In other words, the whole cross sectional area of the paths  10   b ,  20   a  and  20   c  becomes smaller than that of the paths  10   a ,  10   c  and  20   b . Consequently, the pressure of the liquid-phase coolant rising in the paths  10   b ,  20   a  and  20   c  is higher than that in the conventional art. 
   With the above establishment, the evaporator  1  of this embodiment enables an increasing of the quantity of liquid-phase coolant flowing in the upper side in paths  10   b ,  20   a  and  20   c  where the liquid-phase coolant used to be short conventionally. In other words, the liquid phase coolant rising in the paths  10   b ,  20   a  and  20   c  can rise higher than that in the conventional art. In the evaporator  1  where the upwind-side heat exchanging part  20  is superimposed on the downwind-side heat exchanging part  10  in the flowing direction of wind, consequently, it is possible to reduce an area causing a rise in “blowout” temperature of the liquid-phase coolant due to its short supply, as shown in  FIG. 15B . 
   In the evaporator  1  of the embodiment, additionally, since the communication passage  9  that communicates the most downstream-side part  12   b  (in the flowing of coolant) of the downwind-side heat exchanging part  10  with the most upstream-side part  22   a  (in the flowing of coolant) of the upwind-side heat exchanging part  20  is formed in one body with the side plate  35  for reinforcing the evaporator  1 , there is no need to prepare any exclusive member for the communication passage, whereby the manufacturing cost can be saved. 
   In summary, since it is established that the number of heat exchanging passages in the paths each where the coolant downs is smaller than the number of heat exchanging passages in the paths each where the coolant rises, it becomes possible to increase the quantity of coolant flowing in the former paths that are apt to be short in supplying the coolant. Consequently, it is possible to reduce an area causing a rise in “blowout” temperature of the coolant due to the short supply. 
   Finally, it will be understood by those skilled in the art that the foregoing descriptions are nothing but one embodiment of the disclosed evaporator and therefore, various changes and modifications may be made within the scope of claims.