HEAT EXCHANGER

CROSS REFERENCE TO RELATED APPLICATIONS

This application is an application filed under 35 U. S. C. § lll(a) claiming the benefit pursuant to 35 U. S. C. § 119(e)(l) of the filing date of Provisional Application No. 60/655,419 filed February 24, 2005 pursuant to 35 U. S. C. § lll(b) .

TECHNICAL FIELD

[0001]

The present invention relates to a heat exchanger for a refrigerant cycle which constitutes, for example, an automotive air conditioner.

[0002]

In the present specification and claims , the top and bottom of each drawing will be referred to as "top" (or up, upper, or a similar expression) and "bottom" (or down, lower, or a similar expression) , respectively.

BACKGROUND ART

[0003]

In recent years , there has been known a heat exchanger which is used as a heat exchanger for a refrigerant cycle constituting an automotive air conditioner and which

facilitates mounting of the heat exchanger to the vehicle body. The heat exchanger has a condenser section having a pair of headers spaced apart from each other, a plurality of heat exchange tubes which are disposed between the headers so that opposite end portions of the tubes are connected to their corresponding headers , and a corrugate fin which is disposed between, and is bonded to, mutually neighboring heat exchanger tubes; a subcooling section having a pair of headers spaced apart from each other, a plurality of heat exchange tubes which are disposed therebetween so that opposite end portions of the tubes are connected to their corresponding headers , and a corrugate fin which is disposed between, and is bonded to, mutually neighboring heat exchanger tubes ; and a vertical liquid receiver which is fixedly secured to one of the headers of the condenser section and one of the headers of the subcooling section, while bridging them. This heat exchanger is configured such that a pair of tanks spaced apart from each other are divided by partition members into the two headers of the condenser section and the two headers of the subcooling section, and that the liquid receiver includes a block having a refrigerant inflow passage which is in fluid communication with one of the headers of the condenser section and a refrigerant outflow passage which is in fluid communication with one of the headers of the subcooling section, the block being fixedly secured to one of the tanks so as to connect the two headers , and a vertical hollow cylindrical liquid

receiver main body whose bottom is detaciiably fixed to the block, wherein a desiccant is placed within the liquid receiver main body. In this heat exchanger, in order to improve the refrigerating performance of the refrigerant cycle, a liquid refrigerant which has been condensed in the condenser section is further cooled, or supercooled, in the subcooling section to a temperature 5 to 15°C lower than the condensation temperature.

[0004]

However, the above-mentioned existing heat exchanger has the problem in that since the diameter of the liquid receiver main body is greater than the width as measured in the air flow direction of the condensation section and the subcooling section, useless space is created when the heat exchanger is installed in the engine room. Moreover, there may be required extra parts, such as a sealing member between the liquid receiver main body and the block, and a fixing member for fixedly securing the liquid receiver main body to the block, increasing the number of parts.

[0005]

To cope with the above problem, a heat exchanger having the following structure had previously been developed. Specifically,, the heat exchanger includes a condenser section having a pair of headers spaced apart from each other, a plurality of heat exchange tubes which are disposed between the headers so that opposite end portions of the tubes are connected to their corresponding headers , and a corrugate fin

which is disposed between, and is bonded to, mutually neighboring heat exchanger tubes; a subcooling section disposed above the condenser section and having a pair of headers spaced apart from each other, a plurality of heat exchange tubes which are disposed therebetween so that opposite end portions of the tubes are connected to their corresponding headers , and a corrugate fin which is disposed between, and is bonded to, mutually neighboring heat exchanger tubes; and a gas-liquid separation section which is provided between the condenser section and the subcooling section; wherein the gas-liquid separation section includes a pair of headers which are spaced apart from each other and a single straight pipe which is disposed therebetween so that opposite end portions of the pipe are connected to their corresponding headers, the passage of the pipe having a cross sectional area greater than that of the heat exchange tubes of the condenser section and the subcooling section. This heat exchanger is configured such that a pair of tanks spaced apart from each other are divided by partition members into the two headers of the condenser section, the two headers of the subcooling section, and the two headers of the gas-liquid separation section, and that a refrigerant flowing out of the condenser section passes through the gas-liquid separation section and enter the subcooling section (see Japanese Patent No. 3158509).

[0006]

Incidentally, in a refrigerant cycle, a desiccant is

required to be placed so as to remove moisture contained in a refrigerant . As mentioned above , in the heat exchanger including the liquid receiver comprising the block and the vertical hollow cylindrical liquid receiver main body, a desiccant is placed in the liquid receiver main body. However, in the heat exchanger described in the above- mentioned patent, it is extremely difficult to insert a desiccant into the straight pipe in the gas-liquid separation section after brazing the tanks, the heat exchange tubes, the corrugate fins, and the straight pipe together.

[0007]

An object of the present invention is to solve the above problem and to provide a heat exchanger into which a desiccant can be easily loaded.

DISCLOSURE OF THE INVENTION

[0008]

To achieve the above object, the present invention comprises the following modes .

[0009]

1) A heat exchanger comprising a pair of headers spaced apart from each other and a plurality of heat exchange tubes which are disposed therebetween and have opposite end portions connected to the corresponding headers , whereby a refrigerant circulatory pathway is formed therein, wherein either one of the headers has a desiccant loading member fixed thereto, a holding member holding a desiccant is

detachably attached to the desiccant loading member, and is inserted into the refrigerant circulatory pathway through an insert hole formed in the header. [0010]

2) A heat exchanger according to par. 1), wherein the desiccant loading member has a holding-member insertion through hole in fluid communication with the insert hole of the header, and the holding member is inserted into the refrigerant circulatory pathway through the holding-member insertion through hole of the desiccant loading member and the insert hole of the header.

[0011]

3 ) A heat exchanger according to par . 1 ) , wherein the desiccant loading member also serves as a joint member which connects a refrigerant inlet tube or a refrigerant outlet tube to the header, the desiccant loading member is provided with a refrigerant passage in fluid communication with a refrigerant passage hole formed in the header and a communicating hole establishing fluid communication between the refrigerant passage and the insert hole of the header, a part of the refrigerant passage and the communicating hole form a holding-member insertion through hole, and the holding member is inserted into the refrigerant circulatory pathway from an outer end opening of the refrigerant passage through the holding-member insertion through hole and the insert hole of the header.

[0012]

4) A heat exchanger comprising a condenser section including a pair of headers spaced apart from each other and a plurality of heat exchange tubes which are disposed therebetween, with opposite end portions of the tubes being connected to their corresponding headers; a subcooling section including a pair of headers spaced apart from each other and a plurality of heat exchange tubes which are disposed therebetween, with opposite end portions of the tubes being connected to their corresponding headers ; and a gas-liquid separation section provided between the condenser section and the subcooling section and including a pair of headers spaced apart from each other and a liquid receiving tube disposed therebetween, with opposite end portions of the tube being connected to the corresponding headers , and the heat exchanger being configured to allow a refrigerant to flow out of the condenser section into the subcooling section via the gas-liquid separation section, wherein either one of _. the headers of the gas-liquid separation section has a desiccant loading member fixed thereto, a holding member holding a desiccant is detachably attached to the desiccant loading member and is inserted into the liquid receiving tube through an insert hole formed in the header of the gas-liquid separation section.

[0013]

5 ) A heat exchanger according to par . 4 ) , wherein the desiccant loading member also serves as a joint member which connects a refrigerant outlet tube to the header of the

subcooling section. [0014]

6 ) A heat exchanger according to par . 5 ) , wherein the desiccant loading member is fixed to the header of the gas- liquid separation section and the header of the subcooling section while bridging them, the desiccant loading member is provided with a refrigerant passage in fluid communication with a refrigerant outlet formed in the header of the subcooling section and a communicating hole establishing fluid communication between the refrigerant passage and the insert hole of the header of the gas-liquid separation section, a part of the refrigerant passage and the communicating hole form a holding-member insertion through hole, and the holding member is inserted into the liquid receiving tube from an outer end opening of the refrigerant passage through the holding-member insertion through hole and the insert hole of the header.

[0015]

7 ) A heat exchanger according to par. 5 ) , wherein the desiccant loading member is fixed to the header of the gas- liquid separation section, the desiccant loading member is provided with a refrigerant passage which is in fluid communication with a refrigerant outlet formed in the header of the subcooling section, via a tubular communication member, and a communicating hole establishing fluid communication between the refrigerant passage and the insert hole of the header of the gas-liquid separation section, a

part of the refrigerant passage and the communicating hole form a holding-member insertion through hole, and the holding member is inserted into the liquid receiving tube from an outer end opening of the refrigerant passage through the holding-member insertion through hole and the insert hole of the header. [0016]

8) A heat exchanger according, to par. 5), wherein the holding member comprises a tubular main body having an open first end and a closed second end and a cap attached to the open first end of the main body so as to close the first end of the main body, the desiccant is placed in the holding member, and refrigerant-passage through holes are formed in at least either one of a circumferential wall of the main body and a closing wall at the second end of the main body so as to enable the refrigerant to come into contact with the desiccant .

[0017]

9) A heat exchanger according to par. 8), wherein the cap for the holding member has an outward flange portion, and a receiving portion is provided at a refrigerant-passage-side end portion of the communicating hole of the desiccant

^• loading member so as to receive the outward flange portion of the cap from the side where the header of the gas-liquid separation section is present . [0018]

10) A heat exchanger according to par.. 8), wherein the

cap for the holding member is detachably attached to the first end of the main body. [0019]

11) A heat exchanger according to par. 9), wherein a portion of the cap other than the outward flange portion is detachably inserted into the communicating hole of the desiccant loading member.

[0020]

12) A heat exchanger according to par. 4), wherein a pair of tanks spaced apart from each other are divided by partition members into the headers of the condenser section, the headers of the subcooling section, and the headers of the gas-liquid separation section.

[0021]

13) A heat exchanger according to par. 12), wherein the width, as measured in the air passage direction, of the liquid receiving tube of the gas-liquid separation section is equal to or smaller than the width, as measured in the air passage direction, of the tank.

[0022]

14) A heat exchanger according to par. 4), wherein the condenser section is provided above the gas-liquid separation section and the subcooling section is provided below the gas- liquid separation section.

[0025]

In the heat exchanger of par. 1), the desiccant loading member is fixed to the header by brazing simultaneously with

brazing of, for example, the headers and the heat exchange tubes . The holding member holding the desiccant is detachably attached to the desiccant loading member brazed to the header and is inserted into the refrigerant ciculartory pathway through the insert hole of the header. Consequently, the operation of loading the desiccant into the heat exchanger becomes easier. Moreover, the desiccant can be easily replaced or replenished by detaching the holding member from the refrigerant-placement member.

[0026]

In the heat exchanger of par. 2), since the holding- member insertion through hole in fluid communication with the insert hole of the header is formed in the refrigerant- placement member, and the holding member is inserted to the refrigerant circulatory pathway through the holding-member insertion through hole of the refrigerant-placement member and the insert hole of the header, the operation of detachably attaching the holding member to the desiccant loading member fixed to the header can be performed relatively easily.

[0027]

With the heat exchanger of par. 3), since the desiccant loading member also serves as a joint member which connects a refrigerant inlet tube or a refrigerant outlet tube to the header, the number of the parts decreases, and thus the cost can be reduced. Further, the desiccant loading member is provided with a refrigerant passage in fluid communication

with a refrigerant passage hole formed in the header and a communicating hole establishing fluid communication between the refrigerant passage and the insert hole of the header, a part of the refrigerant passage and the communicating hole form a holding-member insertion through hole, and the holding member is inserted into the refrigerant circulatory pathway from an outer end opening of the refrigerant passage through the holding-member insertion through hole and the insert hole of the header. Therefore, the operation of detachably attaching the holding member to the desiccant loading member fixed to the header can be performed relatively easily.

[0028]

In the heat exchanger of par. 4), the desiccant loading member is fixed to the header by brazing simultaneously with brazing of, for example, the headers of the gas-liquid separation section and the liquid receiving tube. The holding member holding the desiccant is detachably attached to the desiccant loading member brazed to the header and is inserted into the liquid receiving tube through the insert hole of the header. Consequently, the operation of loading the desiccant into the heat exchanger becomes easier. Moreover, the desiccant can be easily replaced or replenished by detaching the holding member from the refrigerant- placement member .

[0029]

With the heat exchanger of par. 5), since the desiccant loading member also serves as a joint member which connects a

refrigerant outlet tube to the header of the subcool±ng section, the number of the parts decreases, and thus, the cost can be reduced.

[0030]

With the heat exchanger of par. 6), since a sealing member for preventing leakage of the refrigerant is not required to be placed between the desiccant loading member and the holding member, the number of the parts decreases further. Specifically, in a case where a refrigerant outlet tube is connected to the joint member by use of a fixing member, a sealing member is generally disposed between the joint member and the fixing member. Therefore, once the refrigerant outlet tube is connected to the joint member by use of fixing member after the holding member is inserted into the liquid receiving tube through the holding-member insertion through hole and the insert hole of the header from the outer end opening of the refrigerant passage, by the effect of the sealing member placed between the joint member and the fixing member, leakage of the refrigerant through the gap between the desiccant loading member and the holding member is prevented. Moreover, since the desiccant loading member is fixedly secured to the header of the gas-liquid separation section and the header of the subcooling section while bridging them, the refrigerant passage in fluid communication with the refrigerant outlet provided on the header of the subcooling section and the communicating hole which establishes fluid communication between the refrigerant

passage and the insert hole of the header of the gas-liquid separation section are formed in the desiccant loading member, a part of the refrigerant passage and the communicating hole form the holding-member insertion through hole, and the holding member is inserted into the liquid receiving tube through the holding-member insertion through hole and the insert hole of the header from the outer end opening of the refrigerant passage. Therefore, the operation of detachably attaching the holding member to the desiccant loading member fixed to the header can be performed relatively easily.

[0031]

With the heat exchanger of par. 7), since a sealing member for preventing leakage of the refrigerant is not required to be placed between the desiccant loading member and the holding member, the number of the parts decreases further. Specifically, in a case where a refrigerant outlet tube is connected to the joint member by use of a fixing member, a sealing member is generally disposed between the joint member and the fixing member. Therefore, once the refrigerant outlet tube is connected to the joint member by use of fixing member after the holding member is inserted into the liquid receiving tube through the holding-member insertion through hole and the insert hole of the header from the outer end opening of the refrigerant passage, by the effect of the sealing member placed between the joint member and the fixing member, leakage of the refrigerant through the

gap between the desiccant loading member and the holding member is prevented. Moreover, since the desiccant loading member is fixedly secured to the header of the gas-liquid separation section, the refrigerant passage which is in fluid communication with the refrigerant outlet formed in the header of the subcooling section, via a tubular communication member, and the communicating hole which establishes fluid communication between the refrigerant passage and the insert hole of the header of the gas-liquid separation section are formed in the desiccant loading member, a part of the refrigerant passage and the communicating hole form the holding-member insertion through hole, and the holding member is inserted into the liquid receiving tube through the holding-member insertion through hole and the insert hole of the header from the outer end opening of the refrigerant passage. Therefore, the operation of detachably attaching the holding member to the desiccant loading member fixed to the header can be performed relatively easily.

[0032]

In the heat exchanger of par . 8 ) , the holding member has a some degree of stiffness, which facilitates an operation of inserting the holding member into the liquid receiving tube through the holding-member insertion through hole and the insert hole of the header from the outer end opening of the refrigerant passage as well as an operation of removing the holding member .

[0033]

In the heat exchanger of par . 9 ) , when the holding member is inserted into the liquid receiving tube through the holding member insertion portion and the insert hole of the header from the outer end opening of the refrigerant passage, the outward flange is received by the receiving portion, whereby positioning of the holding member to the inserted position can be performed easily.

[0034]

In the heat exchanger of par. 10), the desiccant in the holding member can be easily replaced or replenished.

[0035]

In the heat exchanger of par. 11), since a portion of the cap other than the outward flange portion is detachably fitted into the communicating hole of the desiccant loading member, wobble of the holding member is prevented.

[0036]

With the heat exchanger of par. 12), the number of the parts of the entire device. can be reduced.

[0037]

With the heat exchanger of par. 13), the liquid receiving tubes never protrude from the tanks as viewed in the air flow direction, useless space can be eliminated when the heat exchanger is placed in an engine room.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view showing the overall structure of a first embodiment of the heat exchanger of the

present invention. FIG. 2 is an enlarged fragmentary vertical sectional view showing a portion of the heat exchanger shown in FIG. 1. FIG. 3 is an enlarged view of the main portion of FIG. 2. FIG. 4 is an exploded perspective view showing, on an enlarged scale, the first headers of the gas-liquid separation section and the subcooling section of the heat exchanger shown in FIG. 1. FIG. 5 is an exploded perspective view showing, on an enlarged scale, the second header of the gas-liquid separation section of the heat exchanger shown in FIG. 1. FIG. 6 is a view corresponding to FIG. 3 showing a second embodiment of the heat exchanger of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0038]

Embodiments of the present invention will next be described with reference to the accompanying drawings .

[0039]

In the following description, the term "aluminum" encompasses not only pure aluminum but also aluminum alloys. Also, in the following description, the right and left of FIG. 1 will be referred to as "right" and "left," respectively, and the backside of the sheet of FIG. 1 (the downstream side of air flow) will be referred to as "front," and the opposite side as "rear."

[0040]

FIG. 1 shows the entire structure of a first embodiment

of the heat exchanger of the present invention; and FIG. 2 to FIG. 5 show a main portion of the structure.

[0041]

In FIG. 1, the heat exchanger (1) has a condenser section (2) and a subcooling section (3) on a common vertical plane, so that the two sections are spaced apart in the upper-lower relation, with the condenser section (2) being on the upper side. The heat exchanger (1) also has a gas-liquid separation section (4) between the condenser section (2) and the subcooling section ( 3 ) . A refrigerant outflows' from the condenser section (2), enters the gas-liquid separation section (4), passes all the way through the gas-liquid separation section (4), and flows into the subcooling section (3).

[0042]

The condenser section (2) includes first and second aluminum headers ( 5 ) and ( 6 ) , a plurality of flat aluminum heat exchange tubes ( 7 ) , and aluminum corrugate fins ( 8 ) . The headers (5) and (6) extend vertically and are spaced apart from each other in parallel in the left-right direction. The heat exchange tubes (7) are disposed between the two headers ( 5 ) and ( 6 ) at predetermined intervals in the vertical direction, with their width being oriented in the front-rear direction and opposite end portions of the tubes being connected to their corresponding headers ( 5 ) and ( 6 ) . The corrugate fins (8) are disposed between the adjacent heat exchange tubes ( 7 ) and are brazed to the heat exchange tubes

(7). An aluminum side plate (9) is disposed above the top heat exchange tube (7) with a certain space therebetween. An aluminum corrugate fin (8) is also disposed between the side plate ( 9 ) and the top heat exchange tube ( 7 ) , and the corrugate fin (8) is brazed to the side plate (9) and the top heat exchange tube ( 7 ) .

[0043]

The first header (5) is divided into an upper header portion (5a) and a lower header portion (5b) by a plate- shaped partition member (11) disposed at a position slightly lower than the mid point of the header in the vertical direction, and a refrigerant inlet (not illustrated) is provided at an upper end portion of the upper header portion (5a). An aluminum inlet side joint member (10) having a refrigerant passage (not illustrated) in fluid communication with the refrigerant inlet is brazed to the upper end portion of the upper header portion(5a), and an refrigerant inlet tube (12) is secured to the inlet side joint member (10) through the use of an aluminum fixing member (13), whereby the refrigerant inlet tube (12) is connected to the upper header portion (5a). In the condenser section (2), passage groups (14A) and (14B) are provided on the upper and lower sides of the partition member (11), respectively, wherein the passages in each group are defined by a plurality of heat exchange tubes (7) arranged in rows in a vertical direction. The number of the heat exchange tubes ( 7 ) in the upper passage group (14A) is greater than that of the lower passage

group (14B). The flowing directions of the refrigerant in all the heat exchange tubes (7) in each of the passage groups (14A) and (14B) are identical, and the flowing direction of the refrigerant in the passage group (14A) and that of the passage group (14B) are opposite to each other.

[0044]

The subcooling section (3) includes first and second aluminum headers (15) and (16), a plurality of flat aluminum heat exchange tubes (17), and aluminum corrugate fins (18). The headers (15) and (16) extend vertically and are spaced apart from each other in the left-right direction. The heat exchange tubes (17) are disposed between the two headers (15) and (16) at predetermined intervals in the vertical direction, with their width being oriented in the front-rear direction and opposite end portions of the tubes being connected to their corresponding headers (15) and (16). The corrugate fins (18) are disposed between adjacent heat exchange tubes (17) and are brazed to the heat exchange tubes (17). The first header (15) has a refrigerant outlet (31) (see FIG. 2). The heat exchange tubes (17) are identical to the heat exchange tubes ( 7 ) of the condenser section ( 2 ) . An aluminum side plate (19) is disposed below the bottom heat exchange tube (17) with a certain space therebetween. An aluminum corrugate fin (18) is also disposed between the side plate (19) and the bottom heat exchange tube (17), and the corrugate fin (18) is brazed to the side plate (19) and the bottom heat exchange tube (17).

[ 0045 ]

The gas-liquid separation section (4) includes a first and a second aluminum headers (21) and (22) and a plurality of (two in this embodiment) aluminum liquid receiving tubes (23). The headers (21) and (22) extend vertically and are spaced apart from each other in parallel in the left-right direction. The liquid receiving tubes (23) are disposed between the two headers (21) and (22) and separated from each other in the vertical direction, with opposite end portions of the tubes being connected to their corresponding headers

(21) and (22). The liquid receiving tubes (23) are cylindrical tubes having outer diameters equal to or smaller than the width, as measured in the front-rear direction, of the header (21) and (22). No particular limitation is imposed on the cross-sectional shape of the liquid receiving tubes (23), so long as the width in the front-rear direction is equal to or smaller than the width of the headers (21) and

(22) in the front-rear direction, and therefore, square tubes or tubes of any other shape may be used other than cylindrical tubes. The cross-sectional area of the passage of each liquid receiving tube (23) is larger than the cross- sectional area of the passage of each of the heat exchanger tubes (7) and (17). The corrugate fins (8) and (18) are also disposed between the upper liquid receiving tube (23) and the lowest heat exchange tube (7) of the condenser section (2), as well as between the lower liquid receiving tube (23) and the highest heat exchange tube (17) of the subcooling section

(3), and are brazed to the liquid receiving tubes (23) and the heat exchange tubes (7) and (17).

[0046]

As shown in FIG. 2 and FIG. 3, a holding container (24) (a holding member) containing a desiccant (25) is disposed in the lower liquid receiving tube (23). The holding container (24) comprises a tubular container main body (26) and a cap (27). The container main body (26) extends in the left-right direction, and has its left end opened and its right end closed. The cap (27) is detachably attached to the left end portion of the container main body (26) to thereby close the left end opening of the container main body (26). The container main body (26) is made of, for example, synthetic resin and has a plurality of refrigerant-passage through holes (26a) which are formed in the circumferential wall and a right end closing wall so as to enable the refrigerant to come into contact with the desiccant (25). The refrigerant- passage through holes (26a) have a size such that the desiccant (25) cannot pass through the refrigerant-passage through holes (26a). The cap (27) of the holding container (24) is made of, for example, synthetic resin and has a cylindrical columnar shape, and an outward flange portion (27a) is formed integrally at the left end of the cap (27). The outer diameter of the cap (27) is equal or greater than the outer diameter of the container main body (26).

[0047]

The holding container (24) is placed in the liquid

receiving tube (23) through an insert hole (29) provided in the first header (21) of the gas-liquid separation section (4) by use of an aluminum desiccant loading member (28), which is brazed to the first header (15) of the subσooling section (3) and the first header (21) of the gas-liquid separation section (4), while bridging them. The center of the insert hole (29) is equal in height to the center of the lower liquid receiving tube (23). The desiccant loading member (28) also serves as an outlet side joint member which connects a refrigerant outlet tube (30) to the first header (15) of the subcooling section (3).

[0048]

As shown in FIG. 3 and FIG. 4, the desiccant loading member (28) is formed with a refrigerant passage (32) in fluid communication with the refrigerant outlet (31) formed in the first header (15) of the subcooling section (3), and a communicating hole (33) establishing fluid communication between the refrigerant passage (32) and the insert hole (29) of the first header (21) of the gas-liquid separation section (4). The refrigerant passage (32) comprises a first portion (32a) horizontally extending from the left side surface of the desiccant loading member (28) to the right and a second portion (32b) communicating with the right end portion of the first portion (32a) and obliquely extending in a lower right direction to the refrigerant outlet (31). The communicating hole (33) horizontally extends from right end of the first portion (32a) of the refrigerant passage (32) to the right

and opens at right side surface of the desiccant loading member (28). The communicating hole (33) is a stepped hole and has a larger diameter portion (33a) at the left end portion. The inner diameter of a smaller diameter portion (33b) (portion other than the larger diameter portion (33a)) is equal to the outer diameter of the cylindrical columnar portion (portion other than the outward flange portion (27a)) of the cap (27) for the holding container (24). Also, the inner diameter of the larger diameter portion (33a) of the communicating hole (33) is equal to or greater than the outer diameter of the outward flange portion (27a) of the cap (27) for the holding container (24). The step portion formed between the larger diameter portion (33a) and the smaller diameter portion (33b) of the communicating hole (33) is a receiving portion (33c) for receiving the outward flange portion (27a) of the cap (27) for the holding container (24) from the right side where the first header (21) of the gas- liquid separation section (4) is present. The center of the first portion (32a) of the refrigerant passage (32) and the center of the communicating hole (33) are equal in height to the center of the insert hole (29). In addition, the first portion (32a) of the refrigerant passage (32) and the communicating hole (33) form a holding-container insertion through hole (34) (a holding-member insertion through hole).

[0049]

The holding container (24) is detachably inserted into the lower liquid receiving tube (23) from the left end

opening of the first portion (32a) of the refrigerant passage (32) in the desiccant loading member (28) through the holding-container insertion through hole (34) and the insert hole (29) of the first header (21) of the gas-liquid separation section (4). The cylindrical columnar portion (portion other than the outward flange portion (27a)) of the cap (27) for the holding container (24) is. tightly fitted into the smaller diameter portion (33b) of the communicating hole (33), and the outward flange portion (27a) is inserted into the larger diameter portion (33a) and is received or caught by the receiving portion (33c) of the communicating hole (33). Notably, the above-described structure may be modified such that a male screw is formed on the outer circumferential surface of the cylindrical columnar portion (portion other than the outward flange portion (27a)) of the cap (27), a female screw is formed on the inner circumferential surface of the smaller diameter portion (33b) of the communicating hole (33), and the cylindrical columnar portion of the cap (27) is screwed into the smaller diameter portion (33b) of the communicating hole (33).

[0050]

The refrigerant outlet tube (30) is fixedly secured to the desiccant loading member (28) by use of an aluminum fixing member (35), whereby the refrigerant outlet tube (30) is connected to the first header (15) of the subcooling section (3). A through hole (36) extending in the right-left direction is formed in a bottom end portion of the fixing

member (35), an end portion of the refrigerant outlet tube (30) is inserted into and fixed to the left end portion of the through hole (36). Also, a tubular projecting portion (37) which projects to the right direction and is inserted into the left end portion of the first portion (32a) of the refrigerant passage (32) in the desiccant loading member (28) is integrally formed on the right side surface of the fixing member (35) to surround the right end opening of the through hole (36). An 0-ring (38), functioning as a sealing member, is attached to the outer circumferential surface of the tubular projecting portion (37). Furthermore, a bolt insertion hole (39) extending in the left-right direction is formed in the upper end portion of the fixing member (35). An internally threaded, through hole (41) extending in the left-right direction is formed in the upper end portion of the desiccant loading member (28). In a state in which the tubular projecting portion (37) is inserted into the left end portion of the first portion (32a) of the refrigerant passage (32) in the desiccant loading member (28), the fixing member (35) is fixed to the desiccant loading member (28) by use of a bolt (42), which is inserted into the bolt insertion hole (39) from the left side and is screwed into the internally- threaded hole (41) of the desiccant loading member (28). The O-ring (38) seals the gap between the fixing member (35) and the desiccant loading member (28). This O-ring (38) provides sealing in the case where the refrigerant leaks through a clearance between inner surface of the

communicating hole (33) in the desiccant loading member (28) and the outer surface of the cap (27) for the holding container (24).

[0051]

A pair of aluminum tanks (43) and (44) which extend vertically and are spaced apart from each other in the left- right direction are divided by partition members (45), (46), (47), and (48) into the two headers (5) and (6) of the condenser section (2), the two headers (21) and (22) of the gas-liquid separation section (4), and the two headers (15) and (16) of the subcooling section (3). Specifically, the partition member (45) between the first headers (5) and (21) of the condenser section (2) and the gas-liquid separation section (4) has a refrigerant inlet (50) extending entirely except for a circumferential edge portion thereof . The partition member (48) between the second headers (16) and (22) of the subcooling section (3) and the gas-liquid separation section (4) has., at its outwardly offset position, a refrigerant outlet (51), which is considerably smaller than the refrigerant inlet (50). The partition member (46) between the first headers (15) and (21) of the subcooling section (3) and the gas-liquid separation section (4) is formed, integrally with the desiccant loading member (28)/

[0052]

In the heat exchanger ( 1 ) , the refrigerant flows through the refrigerant inlet (12) into the upper header portion (5a) of the first header (5) of the condenser section

(2), then through the upper passage group (14A) into the second header ( 6 ) , and subsequently flows into the lower ' header portion (5b) of the first header (5) through the lower passage group (14B). The refrigerant which has entered the lower header portion (5b) passes through the refrigerant inlet (50) and flows into the first header (21) of the gas- liquid separation section (4), where the refrigerant is pooled. Specifically, the refrigerant is accumulated in the headers (21) and (22) and the liquid receiving tubes (23) of the gas-liquid separation section (4), and then flows into the second header (16) of the subcooling section (3) via the refrigerant outlet (51). The refrigerant, which has entered the second header (16), flows into the first header (15) through the heat exchange tubes (17), and outflows to the refrigerant outlet tube (30) via the refrigerant outlet (31) and the refrigerant passage (32).

[0053]

As shown in FIGS. 2 and 5, the gas-liquid separation section (4) includes flow rate lowering means for lowering the flow rate of the refrigerant which outflows from the condenser section (2) into the gas-liquid separation section (4). The flow rate lowering means includes a mesh material (52) serving as a porous member and extending across the refrigerant inlet (50) of the partition member (45), and a passage extending member (53) provided in the second header (22) so as to surround the refrigerant outlet (51) and to extend the length of the passage through which the

refrigerant moves from the refrigerant inlet (50) to the refrigerant outlet (51).

[0054]

The passage extending member (53) includes an aluminum tubular inner member (54) and an aluminum hollow outer member (55). The aluminum tubular inner member (54) projecting upward is provided on the partition member (48) so as to establish fluid communication with the refrigerant outlet (51). The aluminum hollow outer member (55) projecting upward is provided on the partition member (48) so as to enclose the inner member (54), with the top being closed and a through hole (56) being provided at the lower end of the surrounding wall. The lower end of the inner member (54) is inserted into the refrigerant outlet (51) and fixedly secured to the partition member (48). The outer member (55) includes a surrounding wall (55a) and a top plate (55b). The surrounding wall (55a), formed integral with the partition member (48), projects upward and has a semicircle cross section. The top plate (55b) is integrally formed at the upper end of the surrounding wall (55a) so as to close the upper end opening. The through hole (56) is provided at a lower end portion of the flat wall portion of the surrounding wall (55a). The upper end of the outer member (55) is located lower than the partition member (47). The passage extending member (53), together with the partition member (48), is housed in the right-side tank (44) through a through hole (57) formed in the surrounding wall of the right-side

tank (44) and brazed to the right-side tank (44).

[0055]

When the aforementioned heat exchanger (1) is assembled with a compressor, a decompressor (an expansion valve), and an evaporator, a refrigerating cycle is realized. A refrigerating cycle of this type is used as an air conditioner for a vehicle, such as an automobile.

[0056]

In the aforementioned heat exchanger ( 1 ) , when the refrigerant flows through the lower header portion (5b) of the first header (5) of the condenser section (2), then through the refrigerant inlet (50) into the first header (21) of the gas-liquid separation section (4), the flow rate of the refrigerant is lowered due to the presence of the mesh material (52). The refrigerant, after having passed through the liquid receiving tubes (23) to enter the second header (22), is accumulated in the gas-liquid separation section (4), specifically in the headers (21) and (22) and the liquid receiving tubes (23). Subsequently, the refrigerant flows into the second header (16) of the subcooling section (3) through the refrigerant outlet (51). At this time, the flow rate of the refrigerant is again lowered because the refrigerant flows into the outer member (55) through the through hole (56) of the passage extending member (53), flows upward in the outer member (55) then enters the inner member (54) via the upper end opening thereof and flows out to the second header (16) of the subcooling section (3) through the

refrigerant outlet (51). Therefore, the flow rate of the refrigerant moving from the condenser section (2) into the gas-liquid separation section (4) is lowered, prolonging the time during which the refrigerant stays in the gas-liquid separation section (4) to a certain extent, thus improving the gas-liquid separating effect in the gas-liquid separation section (4). As a result, the quantity of the vapor-phase refrigerant that flows into the subcooling section (3) decreases , attaining a sufficient subcooling effect in the subcooling section (3) and improving the cooling effect of the overall refrigerating cycle.

[0057]

FIG . 6 shows another embodiment of the heat exchanger of the present invention .

[ 0058 ]

In the case of the heat exchanger shown in FIG. 6, the holding container (24) is placed in the liquid receiving tube (23) through an insert hole (29) provided in the first header (21) of the gas-liquid separation section (4) using an aluminum desiccant loading member (60), which is brazed to the first header (21) of the gas-liquid separation section (4), and which also serves as an outlet side joint member which connects the refrigerant outlet tube (30) to the first header (15) of the subcooling section (3).

[0059]

The desiccant loading member (60) is provided with a refrigerant passage (61) horizontally extending to the right

from the left side surface thereof, a stepped through hole (62) extending to the upper direction from the bottom surface thereof for establishing fluid communication between the right end portion of the refrigerant passage (61) and the outside of the desiccant loading member (60), and a communicating hole (33) for establishing fluid communication between the refrigerant passage (61) and the insert hole (29) of the first header (21) of the gas-liquid separation section (4). Also, one end potion of an aluminum tubular communicating member (63) is inserted into a lower, larger diameter portion of the stepped through hole (62) and brazed to the desiccant loading member (60), and the other end portion of the tubular communicating member (63) is inserted into the refrigerant outlet (31) of the subcooling section (3) and brazed to the first header (15), whereby the refrigerant passage (61) of the desiccant loading member (60) communicates with the refrigerant outlet (31) through the tubular communicating member (63). In addition, the refrigerant passage (61) and the communicating hole (33) form a holding-container insertion trough hole (64) (a holding- member insertion through hole) .

[0060]

The holding container (24) is detachably inserted into the lower liquid receiving tube (23) from the left end opening of the refrigerant passage (61) of the desiccant loading member (60) through the holding-container insertion through hole (64) and the insert hole (29). of the first

header (21) of the gas-liquid separation section (4).

[0061]

The partition member (46) between the first header (15) of the subcooling section (3) and the first header (21) of the gas-liquid separation section (4) and the desiccant loading member (60) are separate members.

[0062]

Except for the above-described features, the heat exchanger of this embodiment is substantially identical to that of the heat exchanger of the above-described first embodiment. Like components and like potions are denoted by like reference numerals, and their descriptions are omitted.

INDUSTRIAL APPLICABILITY

The heat exchanger according to the present invention is preferably used in a refrigeration cycle which constitutes an automobile air conditioner, for example.