Patent Publication Number: US-6341647-B1

Title: Separator-integrated condenser for vehicle air conditioner

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application relates to and claims priority from Japanese Patent Application No. 11-26427 filed on Feb. 3, 1999, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to condensers, and particularly to a separator-integrated condenser for a vehicle air conditioner including a separating unit which separates gas-liquid two-phase refrigerant into gas refrigerant and liquid refrigerant and stores liquid refrigerant therein. 
     2. Related Art 
     JP-A-7-180930 discloses a separator-integrated condenser for a vehicle air conditioner which includes a separating unit to reduce a mounting space thereof in a vehicle in comparison with that of the condenser and the separating unit separately mounted. The separating unit is formed into a tank shape, and is disposed to extend in a top-bottom direction of the vehicle (i.e., in a direction of gravity) for separating gas-liquid two-phase refrigerant into gas refrigerant and liquid refrigerant by a density difference between gas refrigerant and liquid refrigerant. A sectional area of the separating unit is set relatively small to further reduce a mounting space of the separator-integrated condenser. The separating unit has an inlet through which refrigerant flows into the separating unit and an outlet through which refrigerant is discharged from the separating unit. The inlet is formed to be disposed below a surface of liquid refrigerant in the separating unit when the separating unit is operated under a normal condition. The outlet is formed below the inlet in the separating unit. As a result, refrigerant from the inlet is introduced directly into a lower part of liquid refrigerant stored in the separating unit, and the surface of liquid refrigerant in the separating unit is restricted from being disturbed by dynamic pressure of entering refrigerant. Therefore, gas refrigerant is restricted from being discharged from the outlet, and gas-liquid two-phase refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant even when the sectional area of the separating unit is relatively small. 
     However, in a vehicle such as a cabover truck or an one-box car in which an engine is disposed in a lower part of a passenger compartment, the above-mentioned separator-integrated condenser needs to be disposed in a substantially horizontal direction. As a result, since the inlet and the outlet are disposed relatively adjacent to each other, gas refrigerant may be discharged from the outlet without being separated from gas-liquid two-phase refrigerant by the separating unit. Even when the separator-integrated condenser is disposed to be inclined at up to 45 degrees with respect to a horizontal direction, gas refrigerant may be also discharged from the outlet. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing problems, it is an object of the present invention to provide a separator-integrated condenser including a separating unit in which gas-liquid two-phase refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant even when the condenser is mounted in a substantially horizontal direction or mounted to be inclined at a predetermined angle with respect to a horizontal direction. 
     According to the present invention, a separator-integrated condenser includes a condensing unit having a core portion for condensing refrigerant and a header tank into which the refrigerant condensed by the core portion is collected, and a separating unit for separating the refrigerant into gas refrigerant and liquid refrigerant. The separating unit is integrally formed with the header tank so that a longitudinal direction of the separating unit coincides with a longitudinal direction of the header tank. The separating unit includes an inlet through which the refrigerant in the header tank is introduced into the separating unit, and an outlet through which the refrigerant is discharged from the separating unit. The inlet is formed at a first longitudinal end of the separating unit, and the outlet is formed at a second longitudinal end of the separating unit. The header tank and the separating unit are inclined at a predetermined angle with respect to a horizontal direction in the longitudinal directions thereof, so that the first longitudinal end of the separating unit is disposed at an upper side of the second longitudinal end of the separating unit. 
     As a result, the inlet is disposed at an upper side of the outlet, and is sufficiently away from the outlet. Therefore, the refrigerant introduced from the inlet is sufficiently separated into gas refrigerant and liquid refrigerant due to gravity while flowing through the separating unit toward the outlet, and the outlet is constantly immersed in the liquid refrigerant stored in the separating unit. As a result, the gas refrigerant is restricted from being discharged from the outlet. 
     When the separating unit is disposed in a substantially horizontal direction, the inlet is formed at an upper side of the outlet in the separating unit. As a result, refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant while flowing a sufficiently long flow path between the inlet and the outlet, and gas refrigerant is restricted from being discharged from the outlet. Thus, even when the separator-integrated condenser including the separation unit is mounted in a substantially horizontal direction or mounted to be inclined at a predetermined angle, refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant by the separating unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This and other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiments described below with reference to the accompanying drawings, in which: 
     FIG. 1 is a partially-sectional front view showing a separator-integrated condenser for a vehicle air conditioner according to a first preferred embodiment of the present invention; 
     FIG. 2 is a partially-sectional side view taken from arrow II in FIG. 1; 
     FIG. 3 is a graph showing a relationship between an amount of refrigerant circulating through a refrigeration cycle and a degree of supercooling of refrigerant for various inclination angle θ of the condenser according to the first embodiment; 
     FIG. 4 is a partially-sectional side view showing a separator-integrated condenser for a vehicle air conditioner according to a second preferred embodiment of the present invention; 
     FIG. 5 is a partially-sectional front view showing a separator-integrated condenser for a vehicle air conditioner according to a third preferred embodiment of the present invention; 
     FIG. 6 is a partially-sectional front view showing a separator-integrated condenser for a vehicle air conditioner according to a fourth preferred embodiment of the present invention; 
     FIG. 7 is a partially-sectional side view taken from arrow VII in FIG. 6; 
     FIG. 8 is a sectional view taken along line VIII—VIII in FIG. 7; and 
     FIG. 9 is a partially-sectional side view showing a separator-integrated condenser for a vehicle air conditioner according to a fifth preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments of the present invention are described hereinafter with reference to the accompanying drawings. 
     A first preferred embodiment of the present invention will be described with reference to FIGS. 1-3. In the first embodiment, as shown in FIG. 1, a refrigeration cycle of a vehicle air conditioner includes a compressor  1 , a separator-integrated condenser  2  (hereinafter referred to as the condenser  2 ) including a separating unit  31  , a sight glass  3  through which an amount of refrigerant circulating through the cycle is checked, a temperature-actuated expansion valve  4  and an evaporator  5 . The units  1 - 5  are connected to each other in this order by metal or rubber pipes to form a closed circuit. 
     The compressor  1  is connected to a vehicle engine (not shown) disposed in an engine compartment of a vehicle through a belt and an electromagnetic clutch  1   a . When an engagement of the electromagnetic clutch  1   a  is achieved, rotational power of the engine is transmitted to the compressor  1 , and the compressor  1  sucks gas refrigerant from an outlet of the evaporator  5 . The compressor  1  compresses the gas refrigerant, and discharges high-temperature high-pressure superheated gas refrigerant toward the condenser  2 . 
     The condenser  2  includes first and second header tanks  21 ,  22  disposed with a predetermined interval therebetween, and a core portion  23  disposed between the first and second header tanks  21 ,  22  for performing heat-exchange. Each of the first and second header tanks  21 ,  22  is formed into a substantially cylindrical shape, and extends in a top-bottom direction in FIG.  1 . The condenser  2  is a so-called multi-flow type. The heater core  23  includes plural flat tubes  24  through which refrigerant flows in a horizontal direction, and plural corrugated fins  25  disposed between adjacent tubes  24  and connected to the tubes  24 . One flow-path end of each tube  24  communicates with the first header tank  21 , and the other flow-path end of each tube  24  communicates with the second header tank  22 . 
     Still referring to FIG. 1, an inlet joint  26  is attached to one longitudinal end of the first header tank  21 , and an outlet joint  27  is attached to the other longitudinal end of the first header tank  21 . Refrigerant is introduced into the first header tank  21  through the inlet joint  26 , and is discharged from the first header tank  21  through the outlet joint  27 . The first header tank  21  is partitioned in a longitudinal direction thereof (i.e., in the top-bottom direction in FIG. 1) by a partition member  28  into tank portions  21   a ,  21   b . Similarly, the second header tank  22  is partitioned in a longitudinal direction thereof by a partition member  29  into tank portions  22   a ,  22   b . The partition member  28  is disposed adjacent to the outlet joint  27 . The partition member  29  is disposed at a substantially same height as the partition member  28 . 
     The second header tank  22  is integrally connected to the separating unit  31  which separates gas-liquid two-phase refrigerant into gas refrigerant and liquid refrigerant and stores liquid refrigerant therein. The separating unit  31  is formed into a substantially cylindrical shape, and is disposed at a side of the second header tank  22  opposite to the core portion  23  to be integrally connected to an outer surface of the second header tank  22 . A height of the separating unit  31  is slightly smaller than that of the second header tank  22 . In the first embodiment, the parts of the condenser  2  are made of aluminum, and are integrally brazed together. 
     The first and second header tanks  21 ,  22  have a substantially same structure. As shown in FIG. 1, the second header tank  22  is formed by a first plate  221  and a second plate  222  each of which has a substantially semicircular cross-section. One flow-path end of each tube  24  is connected to the first plate  221  and is held by the first plate  221 . The second header tank  22  is formed by connecting the first plate  221  and the second plate  222  to have a substantially cylindrical shape. Upper and lower ends of the second header tank  22  are respectively closed by caps  223 ,  224 . 
     The separating unit  31  includes a substantially cylindrical body portion  311 . One longitudinal end of the body portion  311  is closed by a cap  312 . The second plate  222  and the body portion  311  respectively have a flat portion, and are brazed to each other while the flat portion of the second plate  222  contacts the flat portion of the body portion  311 . A substantially-cylindrical base portion  313  is connected to the other longitudinal end of the body portion  311 , and is closed by a cap  314 . The cap  314  is screwed into the base portion  313  detachably and hermetically through a sealing member (not shown). A drying agent  315  for absorbing moisture and a filter  316  for removing foreign matters from refrigerant are disposed on and connected to an upper end of the base portion  313 . The filter  316  is made of a cylindrical shaped net. 
     In the first embodiment, the present invention is applied to an air conditioner for a vehicle such as a cabover truck or one-box car in which the engine is disposed in a lower part of the passenger compartment. Therefore, as shown in FIG. 2, the condenser  2  is mounted to be inclined at a relatively small predetermined inclination angle θ with respect to a horizontal direction due to a limited mounting space of the condenser  2 . In the first embodiment, the inclination angle θ is set to 45 degrees or less. The condenser  2  is disposed at an upstream air side of a radiator (not shown) of the engine, and performs heat exchange between refrigerant flowing through the condenser  2  and air blown by an electrical cooling fan (not shown). Further, the condenser  2  is mounted in a lower part of the passenger compartment in such a manner that a longitudinal direction of the second header tank  22  coincides with a longitudinal direction of the separating unit  31 , and the second header tank  22  and the separating unit  31  are inclined at the inclination angle θ in the longitudinal directions thereof. 
     Refrigerant condensed by the core portion  23  becomes saturated gas-liquid two-phase refrigerant, and is collected into the tank portion  22   a  of the second header tank  22 . An inlet  32  is formed between the second header tank  22  and the separating unit  31  so that refrigerant in the tank portion  22   a  is introduced into the separating unit  31  through the inlet  32 . An outlet  33  is formed between the second header tank  22  and the separating unit  31  so that refrigerant in the separating unit  31  is discharged toward the tank portion  22   b  through the outlet  33 . As shown in FIG. 2, the inlet  32  is formed at one longitudinal end of the separating unit  31 , and the outlet  33  is formed at the other longitudinal end of the separating unit  31 . The one longitudinal end of the separating unit  31  is disposed at an upper side of the other longitudinal end of the separating unit  31  when the condenser  2  is inclined at the inclination angle θ. Therefore, the inlet  32  is disposed at an upper side of the outlet  33  when the condenser  2  is inclined at the inclination angle θ. Thus, although both the inlet  32  and the outlet  33  are formed on a center line  31   b  of the separating unit  31 , the outlet  33  is positioned at a lower side of the inlet  32  in a direction of gravity when the condenser  2  is inclined at the inclination angle θ. Further, the inlet  32  and the outlet  33  are positioned sufficiently away from each other with a relatively large distance therebetween in the longitudinal direction of the separating unit  31 . 
     The inlet  32  is formed by boring the second plate  222  of the second header tank  22  and the body portion  311  of the separating unit  31 . The outlet  33  is formed by boring the second plate  222  and the base portion  313 . In the first embodiment, the separating unit  31  is formed into a pipe shape having a relatively small inner diameter of approximately 30 mm. In FIG. 2, a broken line shows a surface  31   a  of liquid refrigerant stored in the separating unit  31  when the refrigeration cycle is operated under a normal condition. 
     Referring back to FIG. 1, the core portion  23  includes a condensing portion  34  disposed above the partition members  28 ,  29 , and a supercooling portion  35  disposed below the partition members  28 ,  29 . The condensing portion  34  cools and condenses gas refrigerant discharged from the compressor  1  through heat exchange between the gas refrigerant and air from outside the passenger compartment blown by the cooling fan. The supercooling portion  35  supercools liquid refrigerant separated by the separating unit  31  through heat exchange between the liquid refrigerant and air from outside the passenger compartment. Thus, the condenser  2  includes the condensing portion  34 , the separating unit  31  and the supercooling portion  35  connected to each other, and refrigerant flows through the condensing portion  34 , the separating unit  31  and the supercooling portion  35  in this order. 
     Next, an operation of the refrigeration cycle according to the first embodiment will be described. When the air conditioner is turned on, and the engagement of the electromagnetic clutch  1   a  is achieved, rotational power of the engine is transmitted to the compressor  1 , and the compressor  1  compresses refrigerant and discharges superheated gas refrigerant. Then, the superheated gas refrigerant is introduced into the tank portion  21   a  of the first header tank  21  of the condenser  2  from the inlet joint  26 . The gas refrigerant flows through the tubes  24  of the condensing portion  34  from right to left in FIG. 1, and flows into the tank portion  22   a  of the second header tank  22 . While the gas refrigerant flows through the tubes  24  of the condensing portion  34 , the gas refrigerant is heat-exchanged with cool air passing through the condensing portion  34  through the tubes  24  and the fins  25 . As a result, the gas refrigerant is cooled and becomes saturated gas-liquid two-phase refrigerant. The saturated gas-liquid two-phase refrigerant in the tank portion.  22   a  is introduced into the separating unit  31  through the inlet  32 , and is separated into liquid refrigerant and gas refrigerant by the separating unit  31 . The liquid refrigerant is stored in the separating unit  31 . 
     According to the first embodiment, as shown in FIG. 2, the condenser  2  is inclined at the inclination angle θ with respect to the horizontal direction in the longitudinal direction of the second header tank  22  and the separating unit  31 . The inlet  32  is formed at the one longitudinal end of the separating unit  31 , and the outlet  33  is formed at the other longitudinal end of the separating unit  31  disposed at a lower side of the one longitudinal end of the separating unit  31 . Therefore, the outlet  33  is disposed at a lower side of the inlet  32  in the direction of gravity, and the distance between the inlet  32  and the outlet  33  is relatively large. As a result, a length of a flow path of refrigerant between the inlet  32  and the outlet  33  is sufficiently increased as long as a whole longitudinal length of the separating unit  31 . Therefore, the saturated gas-liquid two-phase refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant while flowing the relatively long flow path, and liquid refrigerant is accumulated in a lower portion of the separating unit  31  by density difference between gas refrigerant and liquid refrigerant. 
     Further, as shown in FIG. 2, the surface  31   a  of the liquid refrigerant in the separating unit  31  is above the outlet  33  when the condenser  2  is operated under a normal condition. The surface  31   a  of the liquid refrigerant widely extends in the longitudinal direction of the separating unit  31 , and refrigerant from the inlet  32  is introduced into the separating unit  31  at a position sufficiently away from the outlet  33 . Therefore, dynamic pressure of the introduced refrigerant only disturbs the surface  31   a  adjacent to the inlet  32 , and hardly disturbs the surface  31   a  adjacent to the outlet  33 . As a result, gas refrigerant is restricted from being discharged from the outlet  33 , and only liquid refrigerant is discharged from the outlet  33  toward the tank portion  22   b  of the second header tank  22 . Thus, according to the first embodiment, even when the condenser  2  is mounted to be inclined at the inclination angle θ, the refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant by the separating unit  31 . 
     The liquid refrigerant in the tank portion  22   b  flows into the supercooling portion  35  to be supercooled. The supercooled refrigerant flows into the tank portion  21   b  through the tubes  24 , and is discharged from the condenser  2  through the outlet joint  27 . Then, the supercooled refrigerant flows into the expansion valve  4  through the sight glass  3  to be decompressed by the expansion valve  4  and become low-temperature, low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is evaporated by the evaporator  5  through heat exchange with air to be conditioned. When the refrigerant is evaporated, the refrigerant absorbs heat from air so that air is cooled. Superheated gas refrigerant evaporated by the evaporator  5  is sucked into the compressor  1  to be compressed again. 
     Referring to FIG. 3, an experiment was conducted to investigate a relationship between an amount of refrigerant circulating the refrigeration cycle and a degree of supercooling of refrigerant discharged from the supercooling portion  35 . The experiment was conducted for each inclination angle θ of 5, 20, 45 and 90 degrees. In the experiment, the inner diameter of the separating unit  31  was approximately 30 mm. The results are shown in FIG.  3 . 
     In FIG. 3, when the inclination angle θ is 90 degrees, the separating unit  31  is disposed in a vertical direction, that is, in the direction of gravity. In this case, dynamic pressure of refrigerant from the inlet  32  is applied to a relatively small area of the surface  31   a  of the liquid refrigerant in the separating unit  31 . As a result, the surface  31   a  of the liquid refrigerant is largely disturbed. Especially, since the separating unit  31  has a relatively small inner diameter of 30 mm, the surface  31   a  of the liquid refrigerant is relatively largely disturbed. As a result, the surface  31   a  of the liquid refrigerant in the separating unit  31  becomes unstable, and gas refrigerant may be discharged from the outlet  33 . Therefore, even when the amount of refrigerant circulating the refrigeration cycle is increased, an increase in the degree of supercooling of refrigerant is relatively small. As a result, an improvement of cooling performance of the evaporator  5  is also relatively small. 
     On the other hand, when the inclination angle θ of the separating unit  31  is 5, 20 or 45 degrees, the degree of supercooling of refrigerant is largely increased as the amount of refrigerant circulating through the refrigeration cycle is increased. This shows that when the condenser  2  is inclined at the inclination angle θ of 5, 20 or 45 degrees, gas-liquid two-phase refrigerant is sufficiently separated into gas refrigerant and liquid refrigerant by the separating unit  31 . Thus, according to the first embodiment, even when the separating unit  31  has a relatively small inner diameter of 30 mm, and is disposed to be inclined at a relatively small angle such as 45 degrees or less, the separating unit  31  sufficiently separates gas-liquid two-phase refrigerant into gas refrigerant and liquid refrigerant. 
     A second preferred embodiment of the present invention will be described with reference to FIG.  4 . In this and following embodiments, components which are substantially the same as those in previous embodiments are assigned the same reference numerals. 
     As shown in FIG. 4, in the second embodiment, the condenser  2  is mounted on a vehicle so that the second header tank  22  and the separating unit  31  are disposed in a substantially horizontal direction. That is, in the second embodiment, the inclination angle θ is approximately 0. Further, each inlet  32  and outlet  33  is formed into a rectangular shape extending in the substantially horizontal direction. The inlet  32  is formed above the center line  31   b  and the outlet  33  is formed below the center line  31   b  in the direction of gravity. 
     According to the second embodiment, when the refrigeration cycle is operated under a normal condition, the surface  31   a  of liquid refrigerant in the separating unit  31  is formed between the inlet  32  and the outlet  33  in the direction of gravity. Therefore, even when the condenser  2  is disposed in the substantially horizontal direction, the gas-liquid two-phase refrigerant is sufficiently separated by the separating unit  31  into gas refrigerant and liquid refrigerant. 
     A third preferred embodiment of the present invention will be described with reference to FIG.  5 . In the third embodiment, the present invention is applied to the condenser  2  in which refrigerant flows through an N-shaped flow path in the condensing portion  34 . 
     In the third embodiment, the inlet joint  26  is disposed immediately above the partition member  28  in FIG. 5 in a center part of the first header tank  21  in the longitudinal direction thereof. Further, a partition member  28   a  is additionally disposed in the first header tank  21  above the inlet joint  26  in FIG. 5, so that the first header tank  21  is partitioned into the three tank portions  21   a ,  21   b  and  21   c  in the longitudinal direction thereof. On the other hand, a partition member  29   a  is additionally disposed in the second header tank  22  above the partition member  28   a  in FIG. 5, so that the second header tank  22  is partitioned into the three tank portions  22   a ,  22   b  and  22   c  in the longitudinal direction thereof. 
     According to the third embodiment, refrigerant introduced from the inlet joint  26  into the tank portion  21   a  flows into the tank portion  22   c , the tank portion  21   c , and the tank portion  22   a  in this order through the tubes  24 . That is, refrigerant flows through an N-shaped flow path in the condensing portion  34  in a direction indicated by arrows in FIG.  5 . In the third embodiment, the same effect as in the first and second embodiments is obtained. 
     A fourth preferred embodiment of the present invention will be described with reference to FIGS. 6-8. In the fourth embodiment, separation performance of gas-liquid two-phase refrigerant by the separating unit  31  is improved using not only gravity but also centrifugal force. 
     In the fourth embodiment, as shown in FIG. 6, a guide portion  222   a  is integrally formed with the second plate  222  of the second header tank  22  in the vicinity of the inlet  32 . As shown in FIGS. 7 and 8, the guide portion  222   a  extends from a lower side of the inlet  32  in the direction of gravity to protrude inside the separating unit  31 . In the separating unit  31 , the guide portion  222   a  is curved upwardly along the inlet  32 . Therefore, refrigerant introduced into the separating unit  31  from the inlet  32  is guided by the guide portion  222   a  to flow along an inner wall of the body portion  311  of the separating unit  31  in a circumferential direction thereof. 
     Refrigerant introduced into the separating unit  31  flows at a relatively large speed along the inner wall of the body portion  311  in the circumferential direction, and forms a circular flow in a direction indicated by arrow A in FIGS. 6 and 7 in the separating unit  31 . Therefore, centrifugal force is applied to the circular flow of refrigerant. As a result, liquid refrigerant having a relatively large density is collected onto a surface of the inner wall of the body portion  311 , and gas refrigerant having a relatively small density is collected toward a center of the body portion  311  due to the centrifugal force. Further, liquid refrigerant on the surface of the inner wall of the body portion  311  is collected into a lower portion of the body portion  311  by gravity. 
     According to the fourth embodiment, separation performance of gas-liquid two-phase refrigerant by the separating unit  31  is improved using not only gravity but also centrifugal force. Further, in the fourth embodiment, liquid refrigerant is collected onto the surface of the inner wall of the body portion  311  and gas refrigerant is collected toward the center of the body portion  311 . Therefore, even when the condenser  2  is disposed in a substantially horizontal direction as shown in FIG. 4, the inlet  32  and the outlet  33  do not need to be respectively formed at upper and lower sides of the center line  31   b  of the separating unit  31 , but may be both formed on the center line  31   b . However, in this case, if the inlet  32  and the outlet  33  are respectively formed at upper and lower sides of the center line  31   b  as shown in FIG. 4, separation performance of refrigerant is further improved. 
     A fifth preferred embodiment of the present invention will be described with reference to FIG.  9 . In the fifth embodiment, a separation plate  36  is additionally provided in the condenser  2  of the fourth embodiment. The separation plate  36  is fastened to the inner wall of the body portion  311  of the separating unit  31  between the inlet  32  and the outlet  33 , and protrudes from the inner wall of the body portion  311  to extend slantingly toward the outlet  33 . A gap  37  is formed between an upper end of the separation plate  36  and the inner wall of the body portion  311 . Refrigerant from the inlet  32  flows toward the outlet  33  through the gap  37 . 
     According to the fifth embodiment, a portion below the gap  37  of the separating unit  31  is separated into an inlet-side space disposed at a right side of the separation plate  36  in FIG. 9, and an outlet-side space disposed at a left side of the separation plate  36  in FIG. 9 by the separation plate  36 . Therefore, even when a flow rate of refrigerant is relatively small, liquid refrigerant in the outlet-side space is restricted from returning to the inlet-side space by the separation plate  36 . As a result, even when the flow rate is relatively small, a level of liquid refrigerant in the outlet-side space in the separating unit  31  maintains relatively high, thereby restricting gas refrigerant from being discharged from the outlet  33 . The separation plate  36  may be additionally provided to the first to three embodiments. 
     The present invention may be applied to the condenser  2  disposed in a substantially horizontal direction in the longitudinal direction of the separating unit  31 , and inclined in a direction perpendicular to the longitudinal direction of the separating unit  31 . In this case, the second header tank  22  and the separating unit  31  are disposed below the first header tank  21  in the direction of gravity. 
     Further, in the above-mentioned embodiments, the separating unit  31  may be integrally connected to the first header tank  21 , instead of the second header tank  22 . Also, the core portion  23  may have only the condensing portion  34 , while the supercooling portion  35  is separately formed from the core portion  23  as an independent supercooling unit. In this case, the outlet joint  27  is omitted, and another outlet joint is attached to the separating unit  31 , so that liquid refrigerant in the separating unit  31  is discharged from the outlet joint and flows into the supercooling unit through a pipe. Furthermore, the present invention may be applied to a condenser without the supercooling portion  35 . 
     Although the present invention has been fully described in connection with preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.