JP2017083051A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger capable of preventing drift of a liquid-phase refrigerant in a lower flow-dividing section.SOLUTION: An evaporator 1 to which a heat exchanger is applied, includes a leeward-side tube row 3 and a windward-side tube row 4 composed of a plurality of heat exchange tubes 2, and upper and lower both header portions 5, 6, 7, 8 to which the heat exchange tubes 2 of both tube rows 3, 4 are connected. Two tube groups 13, 14 and 15, 16 are respectively disposed on both tube rows 3, 4, and all header portions 5, 6, 7, 8 are provided with sections 20-27 to which the heat exchange tubes 2 of the tube groups 13-16 are connected. A communication passage 32 is disposed between the second section 21 of the leeward-side lower header portion 6 and a seventh-section 26 of the windward-side lower header portion 8 so that the refrigerant flows toward an upstream side in the refrigerant flowing direction in the seventh section 26 from the second section 21 to the seventh section 26. The communication passage 32 is composed of a through hole 33 formed on a partitioning portion 18a between both lower header portions 6, 8, and a guide portion 34 formed on a part around the communication hole 33 of a face facing the seventh section 26 side of the partitioning portion 18a.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat exchanger used as an evaporator of a vehicle air conditioner, for example.

  In this specification and claims, the top and bottom, left and right in FIGS.

  For example, as an evaporator used in a car air conditioner that is a refrigeration cycle mounted on an automobile, it is composed of a plurality of heat exchange tubes arranged at intervals in the left-right direction with the longitudinal direction oriented in the vertical direction, and the ventilation direction The upper header section and the lower header, which are arranged in two tube rows, and are arranged with the longitudinal direction facing the left and right sides on the upper and lower sides of the heat exchange tubes of each tube row, and to which all the heat exchange tubes of each tube row are connected And two tube groups comprising a plurality of heat exchange tubes arranged in succession in both tube rows, and the upper and lower header portions each have two compartments of the same number as the tube groups of the tube rows. It is provided side by side in the longitudinal direction, and the heat exchange tubes of one tube group are passed through each section, and one tube group of the leeward side tube row The downflow tube group in which the refrigerant flows from top to bottom and the other tube group is the upflow tube group in which the refrigerant flows from bottom to top, and the downflow tube of the leeward tube row in the windward tube row The tube group located on the windward side of the group is an upflow tube group in which the refrigerant flows from bottom to top, and the tube group located on the windward side of the upflow tube group of the leeward tube row in the windward tube row is The downflow tube group in which the refrigerant flows from the top to the bottom, and the section through which the heat exchange tubes of the downflow tube group in the leeward upper header section are the inlet section into which the refrigerant flows, and the upward flow in the leeward upper header section The section through which the heat exchange tubes of the tube group communicate is the outlet section from which the refrigerant flows out, the remaining section is the intermediate section, and the refrigerant flowing into the inlet section Each tube group flows in the same direction through the total heat exchanger tubes and the entire intermediate section enters the outlet compartment, is well known has been made to flow out from the outlet compartment.

  In the above-described well-known evaporator, the section where the heat exchange tube of the upflow tube group in the upwind lower header portion communicates the refrigerant in the longitudinal direction, and also separates the refrigerant into the heat exchange tube of the upflow tube group The downstream end portion in the refrigerant flow direction of the lower branch section is closed, and the section communicating with the heat exchange tube of the downflow tube group in the upwind lower header section flows out of the heat exchange tube of the downflow tube group A lower merging section that causes the refrigerant to merge and flow the refrigerant in the longitudinal direction of the section, and the lower merging section causes the refrigerant to flow in the same direction as the lower branch section of the one lower header portion. The upstream end in the flow direction is closed, and the refrigerant that has flowed out of the heat exchange tubes of the downflow tube group flows in the lower merging section and flows into the lower branch section. It enters, so as to divert the heat exchange tubes of the upflow tube group while flowing the lower shunt compartment in the longitudinal direction.

  However, in the case of the known evaporator described above, the following problems occur. That is, when the gas-liquid two-phase refrigerant flows from the lower merge section into the lower branch section, the liquid phase refrigerant drifts to the downstream side in the refrigerant flow direction of the lower branch section due to inertial force. The amount of liquid-phase refrigerant flowing through the total heat exchange tubes of the upper upward flow tube group becomes uneven in the longitudinal direction of the leeward lower header portion. Therefore, the discharged air temperature, which is the temperature of the blown air that has passed through the ventilation gap between the heat exchange tubes, becomes uneven in the longitudinal direction of the upwind lower header portion.

  In view of this, an evaporator that solves such a problem has been proposed in which a plurality of restrictor plates having restrictor holes are arranged in the lower diversion section (see Patent Document 1).

  However, according to the evaporator described in Patent Document 1, the flow rate of the refrigerant that has passed through the throttle hole is increased, and the amount of refrigerant that drifts downstream in the refrigerant flow direction in the lower branch section may increase. In addition, if the throttle hole is made small in order to suppress an increase in the amount of refrigerant that drifts downstream in the refrigerant flow direction in the lower branch section, the passage resistance in the lower branch section increases and the refrigerant circulation amount decreases. Heat exchange performance is reduced.

JP 2001-74388 A

  An object of the present invention is to provide a heat exchanger that solves the above-described problems, can prevent the liquid-phase refrigerant from drifting in the lower branching section, and can prevent passage resistance from increasing.

  In order to achieve the above object, the present invention comprises the following aspects.

1) Two tube rows composed of a plurality of heat exchange tubes arranged at intervals in the left-right direction with the longitudinal direction facing up and down, and arranged in the ventilation direction, and the heat of each tube row Each tube row is provided with an upper header portion and a lower header portion that are arranged on both upper and lower sides of the exchange tube with the longitudinal direction being directed in the left-right direction, and to which both upper and lower ends of the total heat exchange tubes of each tube row are connected. Are provided with two or more tube groups composed of a plurality of heat exchange tubes arranged in succession, and each lower header portion is provided with the same number of sections as the tube groups of the tube row, and one tube group for each section The heat exchanging tube is made to pass, and the section provided in the one lower header part and the section provided in the other lower header part are arranged in the ventilation direction. The tube group consisting of the heat exchange tubes that lead to one compartment is the upward flow tube group in which the refrigerant flows from the bottom to the top, and the compartment in the lower header part that the heat exchange tube of the upward flow tube group leads to the refrigerant. A lower branch section that divides the refrigerant into the heat exchange tubes of the upward flow tube group while flowing in the longitudinal direction of the section, and the downstream end portion in the refrigerant flow direction of the lower branch section is closed, and the other lower header section The tube group consisting of the heat exchange tubes that lead to the lower branch flow compartments and the compartments arranged in the ventilation direction among all of the compartments is a downflow tube group in which the refrigerant flows from top to bottom, and heat exchange of the downflow tube group The section of the lower header section through which the tube communicates is the longitudinal direction of the section of the refrigerant flowing out from the heat exchange tube of the downflow tube group and the direction opposite to the lower branch section. A heat exchanger in which the upstream merging section of the lower merging section is closed at the upstream end in the refrigerant flow direction,
Between the lower diversion section and the lower merging section, which are aligned in the ventilation direction, the refrigerant is directed from the lower merging section to the lower diversion section toward the upstream in the refrigerant flow direction in the lower diversion section. The heat exchanger is provided with a communication passage that allows it to flow in.

  2) The heat exchanger according to 1), wherein the communication path is provided between a portion near the downstream end in the refrigerant flow direction in the lower merge section and a portion near the upstream end in the refrigerant flow direction in the lower branch section. .

  3) The two lower header portions are formed by dividing the inside of one header tank into two spaces in the ventilation direction by a partition portion extending in the left-right direction, and the communication path includes a through hole formed in the partition portion; The refrigerant that is formed in the portion around the communication hole on the surface facing the lower diversion compartment side of the partition and that flows into the lower diversion compartment from the lower merge compartment through the through hole The heat exchanger as described in 1) or 2) above, which comprises a guide portion that guides upstream in the refrigerant flow direction.

  4) The guide unit guides the refrigerant that has flowed from the lower merging section into the lower branch section through the through hole in the direction away from the partition toward the upstream side in the refrigerant flow direction in the lower branch section. 3) The heat exchanger described.

  5) Each upper header section is provided with the same number of sections as the tube groups of the tube row, and the heat exchange tubes of one tube group are connected to each section, and the heat exchange tubes of the upward flow tube group are connected. The header section is an upper merging section that causes the refrigerant that has flowed out of the heat exchange tubes of the upward flow tube group to merge and that causes the refrigerant to flow in the longitudinal direction of the section, and the upper merging section that passes the refrigerant to the lower side The upstream flow section in the direction of the refrigerant flow is closed in the direction opposite to that of the flow dividing section and the upstream end of the downflow tube group communicates with the heat exchange tube. The upper diversion section for diverting the refrigerant to the heat exchange tubes of the tube group, and the downstream end portion in the refrigerant flow direction of the upper diversion section is closed, and the upper merge section The heat exchange according to any one of 1) to 4) above, wherein a refrigerant outlet is provided at a downstream end portion in the refrigerant flow direction and a refrigerant inlet is provided at an upstream end portion in the refrigerant flow direction in the upper branching section. vessel.

  According to the heat exchangers of the above 1) to 5), the refrigerant is transferred from the lower merging section to the lower divergence section between the lower branch section and the lower junction section arranged in the ventilation direction. Since the communication passage is provided to flow toward the upstream side in the refrigerant flow direction in the lower branch section, a part of the refrigerant flowing in the longitudinal direction in the lower merge section passes through the communication path to the lower side. The refrigerant flows into the shunting section toward the upstream side in the refrigerant flow direction in the lower shunting section, and there is resistance to the flow of the refrigerant that is shunted to the heat exchange tubes of the upflow tube group while flowing in the lower shunting section. Is granted. Therefore, in the evaporator to which the heat exchanger is applied, the liquid-phase refrigerant in the gas-liquid two-phase refrigerant that has flowed into the lower branching compartment flows to the downstream side in the refrigerant flow direction of the lower branching compartment due to inertial force. Is prevented, and the amount of liquid-phase refrigerant flowing through the total heat exchange tubes of the upflow tube group is made uniform. As a result, the discharged air temperature, which is the temperature of the blown air that has passed through the ventilation gap between the heat exchange tubes, is made uniform in the longitudinal direction of the lower header portion. In addition, the passage resistance is reduced as compared with the heat exchanger described in Patent Document 1 in which a plurality of throttle plates having throttle holes are arranged, and performance degradation is prevented.

  In the evaporator to which the heat exchanger of 3) and 4) above is applied, the refrigerant flowing into the lower branch section through the communication path is used as a heat exchange tube of the upward flow tube group while flowing in the lower branch section. Resistance is effectively given to the flow of the refrigerant to be divided.

  In the evaporator to which the heat exchanger of the above 5) is applied, a refrigerant having a relatively low dryness flowing from the refrigerant inlet to the lower merging section through the upper branching section and the downflow tube group is provided with a refrigerant outlet. Since the refrigerant flows into the upflow tube group communicating with the upper merging section, the refrigerant flows into the lower branch section, so that the heat exchange efficiency when the refrigerant flows through the upflow tube group is improved.

It is the perspective view which abbreviate | omitted one part which shows the whole structure of the evaporator to which the heat exchanger of this invention is applied. It is a figure which shows the flow of the refrigerant | coolant in the evaporator of FIG. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG. It is a partially cutaway perspective view showing a partition portion of a lower header tank provided with a communication path.

  Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the heat exchanger according to the present invention is applied to an evaporator of a car air conditioner. In the evaporator, air flows in a direction indicated by an arrow X in FIGS. 1, 2, and 5. Yes.

  In the following description, the term “aluminum” includes aluminum alloys in addition to pure aluminum.

  FIG. 1 shows an overall configuration of an evaporator to which a heat exchanger according to the present invention is applied, and FIG. 2 shows a refrigerant flow in the evaporator of FIG. 3 to 6 show the structure of the main part of the evaporator shown in FIG.

  1 to 4, the evaporator (1) is arranged at equal intervals in the left-right direction with the width direction directed to the ventilation direction indicated by the arrow X in FIGS. 1, 2, and 5 and the longitudinal direction directed to the vertical direction. On the upper and lower sides of the heat exchange tubes (2) of the leeward side tube row (3) and the leeward side tube row (4) consisting of a plurality of aluminum heat exchange tubes (2) arranged An aluminum leeward upper header section (5) and an aluminum leeward lower header section (5) connected to the total heat exchange tube (2) of the leeward side tube row (3), with the longitudinal direction being directed in the left-right direction ( 6) and the heat exchange tubes (2) of the windward tube row (4) are arranged on both upper and lower sides with the longitudinal direction facing left and right, and the total heat exchange tube (2) of the windward tube row (4) Provided with an aluminum upwind header (7) and downwind header (8) To have. The number of heat exchange tubes (2) in the leeward side tube row (3) and the windward side tube row (4) is equal to the interval between the adjacent heat exchange tubes (2).

  Both tube rows (3) (4) are placed outside the ventilation gap (9) between adjacent heat exchange tubes (2) of both tube rows (3) and (4) and outside the heat exchange tubes (2) on both left and right ends. The aluminum corrugated fins (11) are placed so as to be shared across the heat exchange tubes (2) and brazed to both heat exchange tubes (2), and the outer sides of the corrugated fins (11) at the left and right ends. Aluminum side plates (12) are respectively disposed and brazed to the corrugated fins (11). A ventilation gap (9) is also formed between the heat exchange tubes (2) at the left and right ends and the side plates (12). The air that has passed through the ventilation gap (9) between the adjacent heat exchange tubes (2) in the tube rows (3) and (4) is sent into the vehicle compartment of the vehicle in which the vehicle air conditioner is mounted.

  The leeward side tube row (3) is provided with two or more, in this case, first and second two tube groups (13) and (14), each of which is composed of a plurality of heat exchange tubes (2) arranged in series. The upper tube row (4) comprises a plurality of heat exchange tubes (2) arranged in succession, and the same number of third to fourth tubes as the tube group (13) (14) of the leeward tube row (3) Groups (15) and (16) are provided.

  In the leeward side tube row (3), the first and second tube groups (13) and (14) are arranged in order from the right end, and in the leeward side tube row (4), the third and fourth tube groups are arranged. (15) and (16) are arranged in order from the left end. The horizontal width of the first tube group (13) and the fourth tube group (16) is preferably the same as the number of heat exchange tubes (2) included in both the tube groups (13) and (16). The horizontal width of the second tube group (14) and the third tube group (15) and the number of heat exchange tubes (2) included in both the tube groups (14) and (15) may be the same. preferable.

  The leeward upper header portion (5) and the windward upper header portion (7), and the leeward lower header portion (6) and the windward lower header portion (8) are, for example, one aluminum header tank (17) ( 18) It is provided by dividing the interior into two spaces in the ventilation direction by vertical plate-shaped aluminum partitions (17a) (18a) extending in the left-right direction.

  The same number of compartments (20) (23) and (21) (22) as the tube group (13) (14) in the leeward tube row (3) are placed in the left and right header sections (5) and (6) on the leeward side The upper and lower header sections (7) and (8) on the windward side have the same number of sections (24) (27) and (25) and (26) as the tube group of the windward tube row (4) in the left-right direction. It is provided side by side. The first tube group (13) of the leeward side tube row (3) is placed in the first compartment (20) on the right side of the leeward upper header portion (5) and the second compartment (21) on the right side of the leeward lower header portion (6). ) Through the heat exchanger tube (2), the leeward side tube in the third section (22) on the left side of the leeward lower header section (6) and the fourth section (23) on the left side of the leeward upper header section (5) The heat exchange tube (2) of the second tube group (14) in the row (3) is connected, and the left side of the fifth section (24) on the left side of the upwind header section (7) and the left side of the upwind header section (8) The heat exchange tube (2) of the third tube group (15) of the windward side tube row (4) is connected to the sixth section (25) of the windward side, and the seventh section (26) on the right side of the windward lower header part (8). Further, the heat exchange tube (2) of the fourth tube group (16) of the windward side tube row (4) communicates with the eighth section (27) on the right side of the upstream side header portion (7). A refrigerant inlet (28) is provided at the right end of the first section (20), and a refrigerant outlet (29) is provided at the right end of the eighth section (27). Moreover, the 4th division (23) and the 5th division (24) are connected through the communication part (31) provided in the partition part (17a). Furthermore, the left end of the second section (21) and the right end of the third section (22) communicate with each other, and the right end of the sixth section (25) and the left end of the seventh section (26) communicate with each other.

  As described above, the first to fourth tube groups (13), (14), (15) and (16), the first to eighth sections (20) to (27), the refrigerant inlet (28), and the refrigerant outlet (29) By providing the communication portion (31), the first tube group (13) and the third tube group (15) become a downflow tube group in which the refrigerant flows from top to bottom in the heat exchange tube (2). In addition, the second tube group (14) and the fourth tube group (16) are an upflow tube group in which the refrigerant flows from the bottom to the top in the heat exchange tube (2).

  Therefore, the first section (20) of the first section (20) of the leeward side upper header section (5) is a downflow tube group while flowing the refrigerant from the right to the left in the longitudinal direction of the first section (20). This is an upper flow dividing section for dividing the refrigerant into the heat exchange tube (2), and the downstream end in the refrigerant flow direction of the first section (20), that is, the left end is closed. The second section (21) joins the refrigerant that has flowed out of the heat exchange tubes (2) of the first tube group (13), which is the downflow tube group, and the refrigerant flows from the right to the left in the second section (21). It is a lower merging section that flows in the longitudinal direction, and the upstream end, that is, the right end of the second section (21) in the refrigerant flow direction is closed and the left end communicates with the third section (22). The third section (22) separates the refrigerant from the right to the left while flowing in the longitudinal direction of the third section (22) to the heat exchange tube (2) of the second tube group (14), which is the upflow tube group. It is a side branching section, the downstream end in the refrigerant flow direction of the third section (22), that is, the left end is closed, and the right end communicates with the second section (21). A 4th division (23) is an upper side merge division which joins the refrigerant | coolant which flowed out from the heat exchange tube (2) of the 2nd tube group (14) which is an upflow tube group. The fifth section (24) diverts the refrigerant flowing from the fourth section (23) through the communication section (31) to the heat exchange tube (2) of the third tube group (15) which is the downflow tube group. This is the upper branch section. The sixth section (25) joins the refrigerant that has flowed out of the heat exchange tubes (2) of the third tube group (15), which is the downflow tube group, and the refrigerant flows from the left to the right in the sixth section (25). It is a lower side merging section that flows in the longitudinal direction. The upstream end, that is, the left end of the sixth section (25) in the refrigerant flow direction is closed, and the right end communicates with the seventh section (26). The seventh section (26) distributes the refrigerant to the heat exchange tube (2) of the fourth tube group (16), which is the upflow tube group, while flowing the refrigerant from left to right in the longitudinal direction of the seventh section (26). The downstream branching section to be made is closed at the downstream end in the refrigerant flow direction of the seventh section (26), that is, the right end, and the left end communicates with the sixth section (25). The eighth section (27) joins the refrigerant that has flowed out of the heat exchange tubes (2) of the fourth tube group (16), which is the upflow tube group, and the refrigerant flows from the left to the right in the eighth section (27). It is an upper merge section that flows in the longitudinal direction, and the upstream end, that is, the left end of the eighth section (27) in the refrigerant flow direction is closed.

  Between the seventh section (26), which is the lower branch section aligned in the ventilation direction, and the second section (21), which is the lower junction section, the refrigerant is supplied from the second section (21) to the seventh section (21). 26) is provided with a communication path (32) for flowing in toward the upstream side (left side) in the refrigerant flow direction in the seventh section (26). The communication path (32) includes a portion near the downstream end in the refrigerant flow direction (close to the left end) in the second section (21) and a portion near the upstream end (close to the left end) in the refrigerant flow direction in the seventh section (26). It is provided between. The communication path (32) includes a through hole (33) formed in the partition portion (18a) of the lower header tank (18) and a through hole in a surface facing the seventh section (26) side of the partition portion (18a). (33) is formed around the portion, and the refrigerant flowing into the seventh compartment (26) from the second compartment (21) through the through-hole (33) is allowed to pass through the seventh compartment (26). And a guide portion (34) for guiding in a direction (windward side) away from the partition portion (18a) toward the upstream side (left side) in the refrigerant flow direction.

  The evaporator (1) described above constitutes a refrigeration cycle together with a compressor, a condenser as a refrigerant cooler, and an expansion valve as a decompressor, and is mounted on a vehicle, for example, an automobile, as a vehicle air conditioner.

  When the compressor is on, the refrigerant that has passed through the compressor, the condenser, and the expansion valve flows into the first section (20) of the leeward upper header section (5) from the refrigerant inlet (28), and the first section (20). After flowing in the left direction, it is diverted to the heat exchange tube (2) of the first tube group (13), then flows downward in the heat exchange tube (2) and enters the second section (21) to join. Then, it flows in the second section (21) to the left and enters the third section (22). The refrigerant that has entered the third compartment (22) flows to the left in the third compartment (22) and is divided into the heat exchange tubes (2) of the second tube group (14). ) Flows upward and enters the fourth section (23) to join. The refrigerant that has entered the fourth section (23) passes through the communication section (31), enters the fifth section (24) of the upwind header section (7), and performs heat exchange of the third tube group (15). After diverting to the tube (2), flowing downward in the heat exchange tube (2), entering the sixth section (25) and joining, then flowing to the right in the sixth section (25), the seventh Enter compartment (26). The refrigerant that has entered the seventh section (26) flows to the right in the seventh section (26) and is divided into the heat exchange tubes (2) of the fourth tube group (16). ) Flows upward, enters the eighth section (27) and joins, then flows to the right in the eighth section (27), and flows out from the refrigerant outlet (29).

  When the refrigerant flows to the left in the second compartment (21), the portion of the second compartment (21) near the downstream end of the refrigerant flow direction to the portion of the seventh compartment (26) near the upstream end of the refrigerant flow direction, Since the refrigerant flows in the direction away from the partition (18a) (upward) toward the upstream side (left side) in the refrigerant flow direction in the seventh compartment (26), the refrigerant flowing rightward in the seventh compartment (26) Among them, a relatively large resistance is given to the flow of the refrigerant flowing near the partition portion (18a). Accordingly, among the refrigerant flowing in the right direction through the seventh section (26), the refrigerant flowing near the partition portion (18a) is left on the left side (the seventh section (26)) in the fourth tube group (16) which is the upward flow tube group. A large amount of gas flows into the heat exchange tube (2) arranged upstream of the refrigerant flow direction in (2) and rises in the heat exchange tube (2) (see 16A in FIGS. 2 and 4). It flows into the other heat exchange tube (2) of the fourth tube group (16) and rises in the heat exchange tube (2) (see reference numeral 16B in FIGS. 2 and 4). Therefore, in the evaporator (1), the liquid-phase refrigerant in the gas-liquid two-phase refrigerant that has flowed into the seventh compartment (26) from the sixth compartment (25) flows into the seventh compartment (26) due to inertial force. It is prevented from drifting downstream in the direction (right side), and the amount of liquid refrigerant flowing through the total heat exchange tube (2) of the fourth tube group (16) is made uniform. As a result, the temperature of the blown air that has passed through the ventilation gap between the heat exchange tubes (2) of the fourth tube group (16) is the longitudinal direction (left-right direction) of the windward lower header section (8). To be homogenized.

  The heat exchanger according to the present invention is suitably used for an evaporator of a refrigeration cycle constituting a vehicle air conditioner.

(1): Evaporator
(2): Heat exchange tube
(3): Downward tube row
(4): Windward tube row
(5): Upper header on the leeward side
(6): Lower header on the leeward side
(7): Upwind header
(8): Upwind lower header
(13) (14) (15) (16): Tube group
(17) (18): Header tank
(17a) (18a): Partition
(20) (21) (22) (23) (24) (25) (26) (27): Section
(32): Communication passage
(33): Through hole
(34): Guide

Claims (5)

Two tube rows comprising a plurality of heat exchange tubes arranged at intervals in the left-right direction with the longitudinal direction oriented in the up-down direction, and arranged in the ventilation direction, and the heat exchange tubes of each tube row The upper and lower header parts are arranged on both upper and lower sides with the longitudinal direction being arranged in the left and right direction, and the upper and lower end parts of the total heat exchange tubes of each tube row are connected to each tube row, Two or more tube groups consisting of a plurality of heat exchange tubes arranged in series are provided, and the same number of sections as the tube groups in the tube row are provided in each lower header portion, and the heat of one tube group is provided in each section. The exchange tube is communicated, and the compartment provided in the one lower header part and the compartment provided in the other lower header part are arranged in the ventilation direction, and at least of all the compartments of the one lower header part A tube group composed of heat exchange tubes that lead to one compartment is an upward flow tube group in which the refrigerant flows from the bottom to the top, and a compartment in the lower header section that communicates with the heat exchange tube of the upward flow tube group A lower branch section that divides the refrigerant into the heat exchange tubes of the upflow tube group while flowing in the longitudinal direction of the upper flow tube group, and the downstream end portion in the refrigerant flow direction of the lower branch section is closed, and the other lower header section The tube group consisting of the heat exchange tubes communicating with the lower branch flow compartment and the compartments arranged in the ventilation direction among all the compartments is a downward flow tube group in which the refrigerant flows from the top to the bottom, and the heat exchange tube of the downward flow tube group The section of the lower header section that communicates with the refrigerant flows out of the heat exchange tubes of the downflow tube group in the longitudinal direction of the section and in the opposite direction to the lower branch section. With a lower converging section for combining while flowing in earthenware pots, a heat exchanger refrigerant flow direction upstream end of the lower merging section is closed,
Between the lower diversion section and the lower merging section, which are aligned in the ventilation direction, the refrigerant is directed from the lower merging section to the lower diversion section toward the upstream in the refrigerant flow direction in the lower diversion section. The heat exchanger is provided with a communication passage that allows it to flow in. The heat exchanger according to claim 1, wherein the communication path is provided between a portion near the downstream end in the refrigerant flow direction in the lower merging section and a portion near the upstream end in the refrigerant flow direction in the lower branch section. Two lower header portions are formed by dividing the inside of one header tank into two spaces in the ventilation direction by a partition portion extending in the left-right direction, and a communication path is formed with a through hole formed in the partition portion, and a partition portion The refrigerant that is formed in the portion around the communication hole on the surface facing the lower branching compartment side and that flows into the lower branching compartment from the lower joining compartment through the through hole is used as the refrigerant in the lower branching compartment. The heat exchanger according to claim 1, further comprising a guide portion that guides the flow direction upstream side. The guide part guides the refrigerant that has flowed into the lower branching section from the lower joining section through the through hole toward the upstream side in the coolant flow direction in the lower branching section in a direction away from the partition section. The described heat exchanger. Each upper header portion is provided with the same number of compartments as the tube group of the tube row, and the upper header portion through which the heat exchange tubes of one tube group are communicated with each compartment and the heat exchange tubes of the upward flow tube group are communicated. Is an upper merging section that causes the refrigerant that has flowed out of the heat exchange tubes of the upflow tube group to merge and that causes the refrigerant to flow in the longitudinal direction of the section, and the upper merging section is configured to pass the refrigerant to the lower branching section. The section of the upper header section through which the upstream end portion in the refrigerant flow direction is closed and the heat exchange tube of the downflow tube group is communicated is passed through the downflow tube group while flowing the refrigerant in the longitudinal direction of the section. And the downstream end of the upper branch flow section in the refrigerant flow direction is closed, and the upper branch section is closed. The heat exchanger according to any one of claims 1 to 4, wherein a refrigerant outlet is provided at a downstream end portion in the refrigerant flow direction and a refrigerant inlet is provided at an upstream end portion in the refrigerant flow direction in the upper branching section. .

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