US20130175013A1

US20130175013A1 - Heat exchanger

Info

Publication number: US20130175013A1
Application number: US13/822,206
Authority: US
Inventors: Shun Yoshioka; Takayuki Hyoudou; Ryuhei Kaji; Yoshikazu Shiraishi; Akihiro Fujiwara; Jihong Liu
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2010-09-29
Filing date: 2011-09-27
Publication date: 2013-07-11
Also published as: EP2623915B1; CN103154659B; JP2012093075A; CN103154659A; EP2623915A1; WO2012043565A1; JP4983998B2; ES2792461T3; EP2623915A4

Abstract

A heat exchanger includes a pair of headers extending in an up-and-down direction to carry refrigerant, and plural flat tubes connected to the headers at different height positions and extending along a direction intersecting a longitudinal direction of the headers. Each header includes a first member and a flat tube holding member. The first member has a main flow path, and refrigerant connection flow paths to circulate refrigerant between the main flow path and plural refrigerant flow paths formed in the flat tubes. The flat tube holding member holds the flat tubes. End portions of the flat tubes are adhered to the flat tube holding member. Intermediate flow paths interconnect the refrigerant connection flow paths and the plural refrigerant flow paths in the flat tubes. The intermediate flow paths are formed in at least one of the headers and the flat tubes.

Description

TECHNICAL FIELD

The present invention relates to a heat exchanger.

BACKGROUND ART

Conventionally, there has been proposed a layered heat exchanger which, like the one described in patent citation 1 (JP-A No. 2006-284133), is equipped with headers that extend in a vertical direction and plural flat tubes that extend in a direction orthogonal to the length of the headers and are inserted into the headers, with the heat exchanger performing heat exchange between refrigerant flowing through plural holes formed in the flat tubes and air flowing outside the flat tubes in a width direction (transverse direction) of the flat tubes.

SUMMARY OF INVENTION

Technical Problem

In a heat exchanger like the one described in patent citation 1 (JP-A No. 2006-284133), improving the pressure-resistant strength is required in a case where, for example, high-pressure refrigerant (e.g., CO₂refrigerant) flows through it. As a measure for improving the pressure-resistant strength of the headers, reducing the diameter of the headers themselves is conceivable. However, when the diameter of the headers themselves is reduced, the width of the flat tubes is reduced in accompaniment therewith, so there is concern that this will have an impact on the performance of the heat exchanger. On the other hand, when the diameter of the headers is designed to match the width of the flat tubes, there is concern that the diameter of the headers will be unable to be reduced, which is not preferred from the standpoint of improving the pressure-resistant strength.
Further, in a heat exchanger of this configuration in which the flat tubes are inserted into the inside space of the headers through which the refrigerant mainly travels, there is concern that the pressure loss of the refrigerant will occur inside the headers.
Thus, the object of the present invention is to provide a heat exchanger that can achieve both improving the pressure-resistant strength of the headers and suppressing the pressure loss of the refrigerant.

Solution to Problem

A heat exchanger pertaining to a first aspect of the present invention is equipped with a pair of headers and plural flat tubes. The headers extend in an up-and-down direction and refrigerant flows inside them. The plural flat tubes extend in a direction intersecting a longitudinal direction of the headers and are connected to the headers at different height positions. Each of the headers has a first member and a flat tube holding member. The first member has formed therein a main flow path and refrigerant connection flow paths. The main flow path extends in the up-and-down direction and refrigerant flows through it. The refrigerant connection flow paths extend from the main flow path to an end surface in the direction in which the flat tubes are positioned in order to circulate the refrigerant between the main flow path and plural refrigerant flow paths formed in the flat tubes. End portions of the flat tubes are adhered to the flat tube holding member, and the flat tube holding member holds the flat tubes. Additionally, intermediate flow paths that interconnect the refrigerant connection flow paths and the plural refrigerant flow paths in the flat tubes are formed in the headers and/or the flat tubes.
Here, for example, when a heat exchanger is given a configuration in which the flat tubes are inserted into the headers, there is concern that the pressure loss of the refrigerant will occur.
Thus, in the heat exchanger pertaining to the first aspect of the present invention, the flat tubes are held using the flat tube holding member that is separate from the first member having formed therein the main flow path through which the refrigerant flows. That is, a configuration in which the flat tubes are not inserted into the main flow path is employed. Because of this, the pressure loss of the refrigerant can be suppressed. Because of the refrigerant connection flow paths and the intermediate flow paths that are separate from the main flow path, the refrigerant flowing through the main flow path flows to the refrigerant flow paths in the flat tubes.
Further, when this configuration is employed, the diameter of the main flow path does not have to match the width of the flat tubes because the flat tubes do not have to be inserted into the main flow path. Therefore, the diameter of the section of the main flow path through which the refrigerant travels can be reduced and the pressure-resistant strength can be improved.
A heat exchanger pertaining to a second aspect of the present invention is the heat exchanger pertaining to the first aspect of the present invention, wherein the width of the intermediate flow paths is equal to or less than the width of the flat tubes.
In the heat exchanger pertaining to the second aspect of the present invention, the width of the intermediate flow paths is equal to or less than the width of the flat tubes, so the longitudinal direction end surfaces of the flat tubes come into contact with the peripheries of intermediate flow path forming portions forming the intermediate flow paths. Because of this, the positioning of the flat tubes can be performed easily.
A heat exchanger pertaining to a third aspect of the present invention is the heat exchanger pertaining to the first aspect or the second aspect of the present invention, wherein each of the headers further has a second member that is sandwiched between the first member and the flat tube holding member. Additionally, in a case where the intermediate flow paths are formed in the headers and the flat tubes or the headers, the intermediate flow paths are formed in the second member.
In the heat exchanger pertaining to the third aspect of the present invention, both improving the pressure-resistant strength of the headers and suppressing the pressure loss of the refrigerant can be achieved.
A heat exchanger pertaining to a fourth aspect of the present invention is the heat exchanger pertaining to any of the first aspect to the third aspect of the present invention, wherein in a case where L1 is the length, in a direction orthogonal to a longitudinal direction of the first member, of a main flow path forming portion forming the main flow path, π is pi, g is gravitational acceleration, m is the circulating volume of the refrigerant in a gas-liquid two-phase state flowing through the main flow path, x is inlet quality, which is the ratio of the mass flow rate of the refrigerant in a gas-phase state with respect to the total mass flow rate of the refrigerant in a gas-liquid two-phase state inside an inlet header among the pair of headers into which the refrigerant flows from outside, ρ_Gis the density of the refrigerant in a gas-phase state flowing through the main flow path, D is the distance between the uppermost flat tube and the lowermost flat tube, and C₁and C₂are constants, the relationship of
$\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}$
holds true. Additionally, C₁=0.16 and C₂=1.5.
In the heat exchanger pertaining to the fourth aspect of the present invention, when L1 is decided in such a way that the above-described relationship holds true, it is easy to equally divide the refrigerant flowing through the main flow path to the refrigerant connection flow paths. That is, it becomes easier for the refrigerant flowing through the main flow path to flow equally to the refrigerant flow paths in the flat tubes connected to the refrigerant connection flow paths.
A heat exchanger pertaining to a fifth aspect of the present invention is the heat exchanger pertaining to any of the first aspect to the third aspect of the present invention, wherein in a case where L1 is the length, in a direction orthogonal to a longitudinal direction of the first member, of a main flow path forming portion forming the main flow path, π is pi, g is gravitational acceleration, m is the circulating volume of the refrigerant in a gas-liquid two-phase state flowing through the main flow path, x is inlet quality, which is the ratio of the mass flow rate of the refrigerant in a gas-phase state with respect to the total mass flow rate of the refrigerant in a gas-liquid two-phase state inside an inlet header among the pair of headers into which the refrigerant flows from outside, ρ_Gis the density of the refrigerant in a gas-phase state flowing through the main flow path, D is the distance between the uppermost flat tube and the lowermost flat tube, and C₁and C₂are constants, the relationship of
$\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}$
holds true. Additionally, C₁=0.24 and C₂=1.1.
In the heat exchanger pertaining to the fifth aspect of the present invention, when L1 is decided in such a way that the above-described relationship holds true, it is easy to more equally divide the refrigerant flowing through the main flow path to the refrigerant connection flow paths. That is, it becomes easier for the refrigerant flowing through the main flow path to flow more equally to the refrigerant flow paths in the flat tubes connected to the refrigerant connection flow paths.
A heat exchanger pertaining to a sixth aspect of the present invention is the heat exchanger pertaining to the third aspect of the present invention and is further equipped with a securing member. The securing member is sandwiched between the flat tube holding member and the second member and secures the end portions of the plural flat tubes together with the flat tube holding member.
In the heat exchanger pertaining to the sixth aspect of the present invention, the flat tubes can be more stably secured.
A heat exchanger pertaining to a seventh aspect of the present invention is the heat exchanger pertaining to the third aspect or the sixth aspect of the present invention, wherein the second member and the securing member have flat panel shapes.
In the heat exchanger pertaining to the seventh aspect of the present invention, for example, in the case of securing the flat tubes by forming holes in the securing member and putting the flat tubes into those holes, construction is easy to execute because the securing member with a flat panel shape enables that the holes can be formed all at once in the securing member. Further, likewise in the case of forming the intermediate flow paths in the second member also, construction is easy to execute because the holes can be formed all at once in the second member.
A heat exchanger pertaining to an eighth aspect of the present invention is the heat exchanger pertaining to any of the third aspect, the sixth aspect, and the seventh aspect of the present invention, wherein the flat tube holding member covers the second member or the second member and the securing member from outside, and both ends of the flat tube holding member are in contact with and brazed to the first member.
In the heat exchanger pertaining to the eighth aspect of the present invention, the second member and the securing member can be easily secured by the flat tube holding member.
A heat exchanger pertaining to a ninth aspect of the present invention is the heat exchanger pertaining to any of the first aspect to the eighth aspect of the present invention, wherein plural holes are formed in the flat tube holding member.
Here, for example, in the case of connecting the flat tube holding member and the flat tubes and connecting the flat tube holding member and the second member, a flux is applied. Thereafter, in the case of connecting these by brazing or the like, it is assumed that the flux will volatilize.
Thus, in the heat exchanger pertaining to the ninth aspect of the present invention, the plural holes are formed in the flat tube holding member. Because of this, volatilized gas can be removed. Consequently, airtightness between connected members can be ensured.
A heat exchanger pertaining to a tenth aspect of the present invention is the heat exchanger pertaining to any of the first aspect to the ninth aspect of the present invention, wherein the length, in a direction orthogonal to a longitudinal direction of the first member, of a main flow path forming portion forming the main flow path is smaller than the width of the flat tubes.
In the heat exchanger pertaining to the tenth aspect of the present invention, the length, in the direction orthogonal to the longitudinal direction of the first member, of the main flow path forming portion forming the main flow path can be made smaller than the width of the flat tubes because the flat tubes do not have to be inserted into the main flow path.

Advantageous Effects of Invention

In the heat exchanger pertaining to the first aspect of the present invention, both improving the pressure-resistant strength of the headers and suppressing the pressure loss of the refrigerant can be achieved.
In the heat exchanger pertaining to the second aspect of the present invention, the positioning of the flat tubes can be performed easily.
In the heat exchanger pertaining to the third aspect of the present invention, both improving the pressure-resistant strength of the headers and suppressing the pressure loss of the refrigerant can be achieved.
In the heat exchanger pertaining to the fourth aspect of the present invention, it becomes easier for the refrigerant flowing through the main flow path to flow equally to the refrigerant flow paths in the flat tubes.
In the heat exchanger pertaining to the fifth aspect of the present invention, it becomes easier for the refrigerant flowing through the main flow path to flow more equally to the refrigerant flow paths in the flat tubes.
In the heat exchanger pertaining to the sixth aspect of the present invention, the flat tubes can be more stably secured.
In the heat exchanger pertaining to the seventh aspect of the present invention, construction is easy to execute.
In the heat exchanger pertaining to the eighth aspect of the present invention, the second member and the securing member can be easily secured by the flat tube holding member.
In the heat exchanger pertaining to the ninth aspect of the present invention, airtightness between connected members can be ensured.
In the heat exchanger pertaining to the tenth aspect of the present invention, the length, in the direction orthogonal to the longitudinal direction of the first member, of the main flow path forming portion forming the main flow path can be made smaller than the width of the flat tubes because the flat tubes do not have to be inserted into the main flow path.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a heat exchanger (details regarding headers are not shown).

FIG. 2 is an enlarged view of section II of FIG. 1.

FIG. 3 is a plan view of a first header and flat tubes in a case where an upper end member has been removed.

FIG. 4 is a longitudinal cross-sectional view in a case where the first header and the flat tubes in a case where the upper end member and a lower end member have been removed are cut along line IV-IV shown in FIG. 3.

FIG. 5 is a longitudinal cross-sectional view in a case where a first member is cut along line V-V shown in FIG. 3.

FIG. 6 is a schematic perspective view of part of the first member.

FIG. 7 is a longitudinal cross-sectional view in which a flat tube holding member is cut along a cutting line that is parallel, in the longitudinal direction of the flat tube holding member, to line V-V shown in FIG. 3.

FIG. 8 is a longitudinal cross-sectional view in which a second member is cut along a cutting line that is parallel, in the longitudinal direction of the second member, to line V-V shown in FIG. 3.

FIG. 9 is a graph showing the relationship between constants C₁and C₂and flow dividing ability.

FIG. 10 is a longitudinal cross-sectional view showing the flat tube holding member pertaining to modification 1A.

FIG. 11 is a plan view, pertaining to modification 1C, of the first header and the flat tube in a case where the upper end member has been removed.

FIG. 12 is a side view, pertaining to modification 1C, of the first member as seen from the side of the flat tubes.

FIG. 13 is a plan view, pertaining to modification 1D, of the first header and the flat tubes in a case where the upper end member has been removed.

FIG. 14 is a side view, pertaining to modification 1D, of the first member as seen from the side of the flat tubes.

FIG. 15 is a plan view, pertaining to modification 1E, of the first header and the flat tubes in a case where the upper end member has been removed.

FIG. 16 is a plan view, pertaining to modification 1F, of the first header and the flat tubes in a case where the upper end member has been removed.

FIG. 17 is a plan view, pertaining to modification 1 G, of the first header and the flat tubes in a case where the upper end member has been removed.

FIG. 18 is a plan view, pertaining to a second embodiment, of the first header and the flat tubes in a case where the upper end member has been removed.

FIG. 19 is a longitudinal cross-sectional view, pertaining to the second embodiment, in a case where the first header and the flat tubes in a case where the upper end member and the lower end member have been removed are cut along line XIX-XIX shown in FIG. 18.

FIG. 20 is a longitudinal cross-sectional view in a case where a securing member is cut along line XX-XX shown in FIG. 18.

DESCRIPTION OF EMBODIMENTS

A heat exchanger 1 pertaining to embodiments of the present invention will be described below with reference to the drawings.

First Embodiment

(1) Configuration of Heat Exchanger 1

FIG. 1 is a schematic configuration diagram of the heat exchanger 1. FIG. 2 is an enlarged view of section II of FIG. 1.
The heat exchanger 1 is a heat exchanger that uses air as a cooling source or a heating source to condense or evaporate refrigerant, and the heat exchanger 1 is, for example, employed as a heat exchanger that configures a refrigerant circuit of a vapor compression refrigeration apparatus. Here, carbon dioxide refrigerant is used as the refrigerant circulating through the refrigerant circuit.
As shown in FIG. 1 and FIG. 2, the heat exchanger 1 mainly has plural flat tubes 11 a to 11 f, heat transfer fins 12, and a pair of headers 13 and 14. These will be described below.

(1-1) Flat Tubes 11 a to 11 f

Each of the flat tubes 11 a to 11 f is formed by extruding a metal member made of aluminum or an aluminum alloy, for example. The flat tubes 11 a to 11 f extend long in a direction intersecting (specifically, a direction orthogonal to) the longitudinal direction of the later-described headers 13 and 14, and as shown in FIG. 2, the flat tubes 11 a to 11 f are disposed a predetermined interval apart from each other in the up-and-down direction in a state in which long and wide planar portions 111 face the up-and-down direction (the longitudinal direction of the headers 13 and 14). Plural refrigerant flow paths 112 are formed inside each of the flat tubes 11 a to 11 f, and the refrigerant flows in these refrigerant flow paths 112. Specifically, the plural refrigerant flow paths 112 are formed side by side in the transverse direction of the flat tubes 11 a to 11 f in such a way as to penetrate the flat tubes 11 a to 11 f in the longitudinal direction of the flat tubes 11 a to 11 f.
Here, six flat tubes are disposed, but the number of the flat tubes is not limited to this.

(1-2) Heat Transfer Fins 12

The heat transfer fins 12 are corrugated fins configured from metal members made of aluminum or an aluminum alloy, and formed as a result of panel-like members being folded in corrugated shapes in their longitudinal direction. The heat transfer fins 12 are disposed in spaces sandwiched by the flat tubes 11 a to 11 f. The mountain fold sections on the upper ends of the heat transfer fins 12 are joined by brazing or the like to the undersurfaces of the planar portions 111, and the valley fold sections on the lower ends of the heat transfer fins 12 are joined by brazing or the like to the upper portions of the planar portions 111. Further, plural cut-and-raised portions 12 a for improving heat exchange efficiency are cut and raised in louver shapes in the heat transfer fins 12. The cut-and-raised portions 12 a are formed in such a way that their directions of inclination with respect to the air flow direction are opposite between the sections on the upstream side and the sections on the downstream side in the air flow direction (the flow direction of air flowing in the transverse direction (width direction) of the flat tubes 11 a to 11 f).

(1-3)

Headers

13 and 14

As shown in FIG. 1, the headers 13 and 14 are members that are spaced apart from each other and extend in the up-and-down direction (specifically, the vertical direction). Flat tube-use holes (included among these are later-described flat tube-use holes 132 a to 132 f (see FIG. 4) in the first header 13) for connecting the plural flat tubes 11 a to 11 f to the headers 13 and 14 are formed in the outer surfaces of the headers 13 and 14 at different height positions (specifically, a predetermined interval apart from each other) along the longitudinal direction of the headers 13 and 14. Additionally, both longitudinal direction end portions of each of the flat tubes 11 a to 11 f extending in the direction orthogonal to the longitudinal direction of the headers 13 and 14 are inserted into these flat tube-use holes. The flat tube-use holes are formed by stamping or the like.
The headers 13 and 14 have a support function of supporting the flat tubes 11 a to 11 f, an inflow function of allowing the refrigerant to flow into the flat tubes 11 a to 11 f (specifically, the plural refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f), and a merge function of allowing the refrigerant flowing out from the flat tubes 11 a to 11 f (specifically, the plural refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f) to merge.
In the description below, for convenience of description, the header on the left side in FIG. 1 will be called “the first header 13” and the header on the right side in FIG. 1 will be called “the second header 14”. The configuration of the headers 13 and 14 is not limited to the configuration shown in FIG. 1, and a variety of configurations can be applied.
The first header 13 is a cylindrical member that has an outer peripheral portion in which an opening 130 is formed and an upper end and lower end that are closed and extends in the up-and-down direction. The opening 130 has the function of allowing the refrigerant to flow into the first header 13 or allowing the refrigerant to flow outside from the first header 13. Specifically, the opening 130 becomes an inlet for the refrigerant in a case where the heat exchanger 1 functions as an evaporator of the refrigerant and becomes an outlet for the refrigerant in a case where the heat exchanger 1 functions as a condenser of the refrigerant.
The second header 14 is a tubular member that has an outer peripheral portion in which an opening 140 is formed and an upper end and lower end that are closed and extends in the up-and-down direction. The opening 140 has the function of allowing the refrigerant to flow into the second header 14 or allowing the refrigerant to flow outside from the second header 14. Specifically, the opening 140 becomes an inlet for the refrigerant in a case where the heat exchanger 1 functions as a condenser of the refrigerant and becomes an outlet for the refrigerant in a case where the heat exchanger 1 functions as an evaporator of the refrigerant.
The opening 130 and the opening 140 are formed by stamping or the like. Further, pipes 151 and 152 through which the refrigerant flows are connected to the opening 130 and the opening 140.

(2) Regarding the Specific Configuration of the

Headers

13 and 14

The first header 13 and the second header 14 have the same configuration. Therefore, in the description below, only the configuration of the first header 13 will be described and description of the configuration of the second header 14 will be omitted.
FIG. 3 is a plan view of the first header 13 and the flat tubes in a case where an upper end member has been removed. FIG. 4 is a longitudinal cross-sectional view in which the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member and a lower end member have been removed are cut along line IV-IV shown in FIG. 3. FIG. 5 is a longitudinal cross-sectional view in a case where a first member 131 is cut along line V-V shown in FIG. 3. FIG. 6 is a schematic perspective view of part of the first member 131. FIG. 7 is a longitudinal cross-sectional view in which a flat tube holding member 132 is cut along a cutting line that is parallel, in the longitudinal direction of the flat tube holding member 132, to line V-V shown in FIG. 3. FIG. 8 is a longitudinal cross-sectional view in which a second member 133 is cut along a cutting line that is parallel, in the longitudinal direction of the second member 133, to line V-V shown in FIG. 3.
As shown in FIG. 3 to FIG. 8, the first header 13 mainly has a first member 131, a flat tube holding member 132, and a second member 133. These members will be specifically described below.

(2-1) First Member 131

The first member 131 is a member that extends in the vertical direction and is configured from a metal member such as clad metal comprising an aluminum alloy with a low melting point bonded to the surface of another aluminum alloy serving as a core. As shown in FIG. 3 and FIG. 6, the first member 131 has a shape in which a cylinder and a cuboid are combined. The cross section of the first member 131 orthogonal to the longitudinal direction of the first member 131 has a “Ω” shape (a shape in which about ¾ of a circular arc and end portions of that circular arc are joined by a straight line and in which a quadrilateral is connected to that straight line section).
Specifically, the first member 131 has a first portion 331 a, which extends in the vertical direction and has a transverse cross section having a shape in which about ¾ of a circular arc and end portions of that circular arc are joined by a straight line, and a second portion 331 b, which extends in the vertical direction and has a flat panel shape that is long and narrow in the width direction.
As shown in FIG. 3, FIG. 4, and FIG. 6, a refrigerant main flow path 131 a that penetrates the first member 131 (specifically, the first portion 331 a) in the up-and-down direction (specifically, the vertical direction) and through which the refrigerant mainly flows is formed in the first member 131 (specifically, the first portion 331 a). The cross section (transverse cross section) of the refrigerant main flow path 131 a orthogonal to the longitudinal direction of the refrigerant main flow path 131 a has a circular shape. A length L1 (see FIG. 3), in a direction orthogonal to the longitudinal direction of the first member 131, of a refrigerant main flow path forming portion 13 a (see FIG. 3 and FIG. 4) forming the refrigerant main flow path 131 a is 10 mm. Further, the thickness of the first member 131 (the distance between the inner surface of the refrigerant main flow path forming portion 13 a and the outer surface of the first portion 331 a) is preferably 3 mm to 6 mm.
Further, refrigerant connection flow paths 231 a to 231 f that are in communication with refrigerant main flow path 131 a, extend to an end surface in the direction in which the flat tubes 11 a to 11 f are positioned (the direction orthogonal to the longitudinal direction of the first member 131), and penetrate the first member 131 are formed in the first member 131 in order to circulate the refrigerant with the plural refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f. The refrigerant connection flow paths 231 a to 231 f are formed a predetermined interval apart from each other along the longitudinal direction of the first member 131. As shown in FIG. 6, the cross sections of the refrigerant connection flow paths 231 a to 231 f cut in the longitudinal direction of the first member 131 (the vertical direction) have circular shapes. The refrigerant connection flow paths 231 a to 231 f are formed by drilling. A height H1 of the refrigerant connection flow paths 231 a to 231 f (specifically, refrigerant connection flow path forming portions 233 a to 233 f (see FIG. 5) forming the refrigerant connection flow paths 231 a to 231 f) is larger than the thickness of the flat tubes 11 a to 11 f.

(2-2) Flat Tube Holding Member 132

The flat tube holding member 132 is a member to which the end portions of the flat tubes 11 a to 11 f are connected (adhered) and which holds the flat tubes 11 a to 11 f. The flat tube holding member 132 is a member that is configured from a metal member such as clad metal and extends in the vertical direction. As shown in FIG. 3, in a regularly assembled state, the transverse cross section of the flat tube holding member 132 (the cross section orthogonal to the longitudinal direction of the flat tube holding member 132) has a “U” shape whose end portions are bent inward.
In a regularly assembled state, the flat tube holding member 132 is bent inward in such a way as to cover both width direction end portions of the second portion 331 b of the first member 131. Additionally, the inwardly bent end portions of the flat tube holding member 132 are positioned in recessed portion spaces S formed by the first portion 331 a and the second portion 331 b of the first member 131.
As shown in FIG. 3 and FIG. 4, plural flat tube-use holes 132 a to 132 f for inserting the plural flat tubes 11 a to 11 f and holding the flat tubes 11 a to 11 f are formed in the flat tube holding member 132. The flat tube-use holes 132 a to 132 f are formed by stamping or the like. The flat tube-use holes 132 a to 132 f are formed a predetermined interval apart from each other along the longitudinal direction of the flat tube holding member 132. The height of the flat tube-use holes 132 a to 132 f is formed a little smaller than the thickness of the flat tubes 11 a to 11 f. Therefore, by inserting the flat tubes 11 a to 11 f into the flat tube-use holes 132 a to 132 f, the flat tubes 11 a to 11 f are held.
In a state in which the flat tubes 11 a to 11 f are normally attached to the flat tube holding member 132, the end surfaces of the flat tubes 11 a to 11 f on the inserted sides and the end surface of the flat tube holding member 132 on the first member 131 side are positioned in substantially the same position.
FIG. 7 shows a longitudinal cross-sectional view of the flat tube holding member 132 in a state in which the flat tubes 11 a to 11 f are normally attached to the flat tube holding member 132.

(2-3) Second Member 133

As shown in FIG. 3 and FIG. 4, the second member 133 is a member having one end surface adhered to the first member 131 (specifically, the end surface of the second portion 331 b) and another end surface adhered to the end surface of the flat tube holding member 132. That is, the second member 133 is sandwiched between the first member 131 and the flat tube holding member 132.
The second member 133 is configured from a metal member such as clad metal (clad metal with a higher melting point than that of other members is used for the clad metal forming the second member 133) and has a long and narrow flat panel shape extending in the vertical direction. The transverse cross section of the second member 133 has a quadrilateral shape.
As shown in FIG. 4 and FIG. 8, intermediate flow paths 133 a to 133 f that penetrate the second member 133 in a direction orthogonal to the longitudinal direction of the second member 133 are formed in the second member 133. As shown in FIG. 8, the intermediate flow paths 133 a to 133 f have longitudinal cross sections having transversely long and narrow oval shapes. As shown in FIG. 4 and FIG. 8, the plural intermediate flow paths 133 a to 133 f are formed a predetermined interval apart from each other along the longitudinal direction of the second member 133. Additionally, the plural intermediate flow paths 133 a to 133 f are in communication with the refrigerant connection flow paths 231 a to 231 f formed in the first member 131 and the plural refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f.
That is, the second member 133 has the function of enabling the circulation of the refrigerant between the first member 131 having formed therein a flow path (specifically, the refrigerant main flow path 131 a) through which the refrigerant mainly travels and the plural refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f. Specifically, the second member 133 has the function of enabling the circulation of the refrigerant between the plural refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f and the refrigerant main flow path 131 a and refrigerant connection flow paths 231 a to 231 f formed in the first member.
The height of the intermediate flow paths 133 a to 133 f (specifically, the height of intermediate flow path forming portions 134 a to 134 f forming the intermediate flow paths 133 a to 133 f) is larger than the thickness of the flat tubes 11 a to 11 f and is larger than the height H1 of the refrigerant connection flow paths 231 a to 231 f (specifically, the refrigerant connection flow path forming portions 233 a to 233 f). This is to facilitate the circulation of the refrigerant between the first header 13 and the flat tubes 11 a to 11 f.
Further, a width W3 of the intermediate flow paths 133 a to 133 f (specifically, a width W3 of the intermediate flow path forming portions 134 a to 134 f forming the intermediate flow paths 133 a to 133 f) is equal to or less than a width W22 of the flat tubes 11 a to 11 f (see FIG. 7).

(3) Regarding Method of Manufacturing the Heat Exchanger 1

A method of manufacturing the heat exchanger 1 will be described below. In the description below also, description of the second header 14 will be omitted.
First, the first member 131 is formed. Specifically, a long and narrow cylinder-shaped member having an open space (specifically, the refrigerant main flow path 131 a) inside is formed by processing (e.g., extruding) clad metal comprising an aluminum alloy with a low melting point bonded to the surface of another aluminum alloy serving as a core. Then, holes (specifically, the refrigerant connection flow paths 231 a to 231 f) that penetrate the member with the cylindrical shape in a direction orthogonal to the longitudinal direction of the member with the cylindrical shape from the inside space are formed in the cylinder-shaped member by drilling. The holes are formed a predetermined interval apart from each other along the longitudinal direction of the cylinder-shaped member. Because of this, the first member 131 having formed therein the refrigerant main flow path 131 a and the refrigerant connection flow paths 231 a to 231 f is formed.
Next, the second member 133 is formed. Specifically, plural holes (specifically, the intermediate flow paths 133 a to 133 f) are formed in flat panel-shaped clad metal at a predetermined interval apart from each other along the longitudinal direction of the flat panel-shaped clad metal by stamping. Because of this, the second member 133 having formed therein the intermediate flow paths 133 a to 133 f is formed.
Next, holes (specifically, the flat tube-use holes 132 a to 132 f) for holding the flat tubes 11 a to 11 f are formed in flat panel-shaped clad metal at a predetermined interval apart from each other along the longitudinal direction of the flat panel-shaped clad metal by stamping.
Next, the first member 131, the second member 133, the flat panel-shaped clad metal having formed therein the holes for holding the flat tubes 11 a to 11 f, and the flat tubes 11 a to 11 f are assembled in such a way as to be positioned in this order.
Then, the flat panel-shaped clad metal is bent in such a way as to cover the second member 133 from outside along the shape of the second member 133, and both ends of the flat panel-shaped clad metal are brought into contact with, in such a way as to cover from outside, part of the first member 131 (specifically, the second portion 331 b) and positioned in the recessed portion spaces S. Because of this, the flat tube holding member 132 whose transverse cross section has a “U” shape is formed.
Then, the flat tubes 11 a to 11 f are inserted into the flat tube-use holes 132 a to 132 f.
Then, these are joined together by brazing. Here, by using clad metal for the flat tube holding member 132 and joining the flat tube holding member 132 to the flat tubes 11 a to 11 f, leakage of the refrigerant to the outside from the refrigerant flow paths 112 in the flat tubes 11 a to 11 f can be prevented.
The first member 131 is given a configuration in which its upper and lower ends are closed by an upper end member and a lower end member (not shown in the drawings) having the same cross-sectional shape as that of the first member 131, and the upper end member and the lower end member are joined to the first member 131 by brazing.
Further, the second header 14 is joined to the other end portions of the flat tubes 11 a to 11 f in the same way as the first header 13. As described above, the heat exchanger 1 is manufactured.

(4) Flows of the Refrigerant

The series of flows of the refrigerant in the heat exchanger 1 having the above configuration will be briefly described.
(4-1) Flow of the Refrigerant in a Case where the Heat Exchanger 1 Functions as an Evaporator
First, the refrigerant flowing toward the heat exchanger 1 from outside the first header 13 flows into the first header 13 via the opening 130. Here, the first header 13 functions as an inlet header into which the refrigerant flows from outside. The general flow of the refrigerant is such that the refrigerant that has flowed into the first header 13 travels through the refrigerant main flow path 131 a formed in the first member 131, is distributed to the flat tubes 11 f to 11 a, and is substantially equally divided to the refrigerant flow paths 112 formed in the flat tubes 11 f to 11 a.
More specifically, the refrigerant that has flowed into the first header 13 travels through the refrigerant main flow path 131 a formed in the first member 131 and is substantially equally distributed to the refrigerant connection flow paths 231 f to 231 a formed in the first member 131. The refrigerant that has flowed into the refrigerant connection flow paths 231 f to 231 a flows into the intermediate flow paths 133 f to 133 a formed in the second member 133. The refrigerant that has flowed into the intermediate flow paths 133 f to 133 a is substantially equally divided to the plural refrigerant flow paths 112 formed in the flat tubes 11 f to 11 a held in the flat tube holding member 132.
Then, the refrigerant that is equally divided to the refrigerant flow paths 112 flows toward the second header 14. The refrigerant that has merged inside the second header 14 flows out to the outside of the heat exchanger 1 via the opening 140.
As described above, in a case where the heat exchanger 1 functions as an evaporator, the refrigerant flows through the insides of the headers 13 and 14 from the lower space to the upper space.
(4-2) Flow of the Refrigerant in a Case where the Heat Exchanger 1 Functions as a Condenser
In a case where the heat exchanger 1 functions as a condenser, the refrigerant flowing toward the heat exchanger 1 from outside the second header 14 flows into the second header 14 via the opening 140. Here, the second header 14 functions as an inlet header into which the refrigerant flows from outside.
Then, like the flow of the refrigerant in the case where the heat exchanger 1 functions as an evaporator, the refrigerant that has flowed into the second header 14 flows toward the first header 13. The refrigerant that has merged inside the first header 13 flows out to the outside of the heat exchanger 1 via the opening 130.
As described above, in a case where the heat exchanger 1 functions as a condenser, the refrigerant flows through the insides of the headers 13 and 14 from the upper space to the lower space.
Here, as shown in FIG. 3, a width W1 of the refrigerant connection flow paths 231 a to 231 f (specifically, a width W1 of the refrigerant connection flow path forming portions 233 a to 233 f) is the minimum dimension necessary for the refrigerant to travel through in order to enhance the pressure-resistant strength of the first member 131. Therefore, the width W1 of the refrigerant connection flow paths 231 a to 231 f (specifically, the refrigerant connection flow path forming portions 233 a to 233 f) is smaller than a width W2 (see FIG. 7) of the sections of the flat tubes 11 a to 11 f in which the refrigerant flow paths 112 are formed. Thus, here, the width W3 of the intermediate flow paths 133 a to 133 f (specifically, the intermediate flow path forming portions 134 a to 134 f forming the intermediate flow paths 133 a to 133 f) formed in the second member 133 is equal to or greater than the width W2 of the sections of the flat tubes 11 a to 11 f in which the refrigerant flow paths 112 are formed. Because of this, the exchange of the refrigerant between the first member 131 and the plural flat tubes 11 a to 11 f can be performed easily.

(5) Regarding the Refrigerant Main Flow Path 131 a

The length L1 [m], in the direction orthogonal to the longitudinal direction of the first member 131, of the refrigerant main flow path forming portion 13 a forming the refrigerant main flow path 131 a can be decided using equality 1 below.
$\begin{matrix} \frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} & (Equality 1) \end{matrix}$
Here, π is pi. g is gravitational acceleration [m/s²]. m is the circulating volume [kg/s] of the refrigerant in a gas-liquid two-phase state flowing through the refrigerant main flow path 131 a. x is inlet quality, which is the ratio of the mass flow rate of the refrigerant in a gas-phase state with respect to the total mass flow rate of the refrigerant in a gas-liquid two-phase state inside the first header 13 or the second header 14 functioning as the inlet header. ρ_Gis the density [kg/m³] of the refrigerant in a gas-phase state flowing through the refrigerant main flow path 131 a and, in the present embodiment, is a value decided by the evaporation temperature. D is the distance [m] between the upper surface of the uppermost flat tube 11 a and the undersurface of the lowermost flat tube 11 f (see FIG. 4). C₁and C₂are constants.
From the above equality 1, it will be understood that the length L1 is decided by the constants C₁and C₂and the distance D. The distance D is a value unequivocally decided in accordance with the type of the headers 13 and 14.
Here, the inventors of the present invention performed an experiment and discovered the constants C₁and C₂with which flow dividing ability becomes equal to or greater than a predetermined ability (in the present embodiment, 90%). “Flow dividing ability” is an ability indicating how equally the refrigerant can be allowed to flow from the refrigerant main flow path 131 a to the refrigerant connection flow paths 231 a to 231 f and therefore to the refrigerant flow paths 112 in the flat tubes 11 a to 11 f; if the flow dividing ability is equal to or greater than 90%, it can be said that the flow dividing ability is high.
FIG. 9 is a graph showing the relationship between the constants C₁and C₂and the flow dividing ability that is the result of the experiment described above. The experiment that led to the graph of FIG. 9 was performed under the conditions that carbon dioxide refrigerant was used as the refrigerant, headers 13 and 14 in which D was 300 mm to 500 mm and L1 was 5 mm to 15 mm were used, the evaporation temperature was 0° C., and x was 0.2. The same results (that is, values of C₁and C₂with which the flow dividing ability is high) are obtained even if the experimental conditions (e.g., the evaporation temperature and the value of x) are changed somewhat.
In this experiment, a value calculated from expression 2 below is used as a substitute value of the constants C₁and C₂(U_gsis gas speed).
$\begin{matrix} \frac{U_{gs}}{{(gD)}^{0.5}} & (Expression 2) \end{matrix}$
This is because the relationship of equality 4 below can be derived when equality 1 above is divided by the gas speed U_gsdefined from expression 3 below.
$\begin{matrix} U_{gs} = \frac{m \cdot x}{ρ_{G} (\frac{π L 1^{2}}{4})} & (Expression 3) \\ C_{1} \leq \frac{U_{gs}}{{(gD)}^{0.5}} \leq C_{2} & (Expression 4) \end{matrix}$
Looking at the graph of FIG. 9, the value of C₁with which the flow dividing ability becomes equal to or greater than 90% is 0.16, and the value of C₂is 1.5. Further, the value of C₁with which the flow dividing ability becomes equal to or greater than 95% is 0.24, and the value of C₂is 1.1.
Therefore, the value of L1 with which the flow dividing ability is high can be decided using equality 1 and the values of the constants C₁and C₂derived from the graph of FIG. 9.
For example, in a case where D is 500 mm, the evaporation temperature is 7° C. (ρ_Gdecided from this evaporation temperature becomes 122.3 kg/m³), x is 0.15, and m is 100 kg/hr, it suffices to design L1 in such a way that L1 becomes 3.6 mm to 11.0 mm if one wants to obtain a flow dividing ability of 90%, and it suffices to design L1 in such a way that L1 becomes 4.2 to 9.0 mm if one wants to obtain a flow dividing ability of 95%.

(6) Characteristics

(6-1)
For example, in a case where the flat tubes are inserted into the inside spaces of the headers through which the refrigerant mainly travels, there is concern that the pressure loss of the refrigerant will occur. Further, in a heat exchanger of this configuration, when joining together the flat tubes and the headers, it is assumed that brazing filler metal will flow into the headers from the end portions of the flat tubes. In this case, there is concern that the flow path through which the refrigerant mainly travels will end up being blocked as a result of brazing filler metal clogs or the like occurring.
Thus, in the present embodiment, the plural flat tubes 11 a to 11 f are held using the flat tube holding member 132 that is separate from the first member 131 having formed therein the refrigerant main flow path 131 a through which the refrigerant mainly travels. Further, the intermediate flow paths 133 a to 133 f for allowing the refrigerant to flow from the plural flat tubes 11 a to 11 f to the refrigerant main flow path 131 a and for allowing the refrigerant from the refrigerant main flow path 131 a to flow to the flat tubes 11 a to 11 f are formed in the second member 133 that is separate from the first member 131, and the refrigerant connection flow paths 231 a to 231 f for allowing the refrigerant to flow from the refrigerant main flow path 131 a to the intermediate flow paths 133 a to 133 f are formed in the first member 131. Therefore, a configuration in which the flat tubes 11 a to 11 f are not inserted into the refrigerant main flow path 131 a is employed. Because of this, brazing filler metal clogs can be suppressed from occurring in the refrigerant main flow path 131 a through which the refrigerant travels. Further, the pressure loss of the refrigerant can be suppressed.
Further, by employing this configuration, the diameter of the first header 13 and the refrigerant main flow path 131 a do not have to be formed to match the width of the flat tubes 11 a to 11 f. That is, the length L1, in the direction orthogonal to the longitudinal direction of the first member 131, of the refrigerant main flow path forming portion 13 a forming the refrigerant main flow path 131 a (that is, the inner diameter of the refrigerant main flow path forming portion 13 a) can be made smaller than the width W22 of the flat tubes 11 a to 11 f. Therefore, the diameter of the flow path through which the refrigerant mainly travels can be reduced and the pressure-resistant strength of the first header 13 can be improved. Moreover, because the diameter of the refrigerant main flow path 131 a can be reduced, a drop in the flow speed of the refrigerant flowing through the refrigerant main flow path 131 a can be suppressed and the flow dividing ability can be kept high.
(6-2)
In the present embodiment, the second member 133 has a flat panel shape. Holes can be formed easily in the second member 133, so the intermediate flow paths 133 a to 133 f can be formed easily. Therefore, it is easy for a constructor to execute construction.
(6-3)
The width W3 of the intermediate flow paths 133 a to 133 f (specifically, the intermediate flow path forming portions 134 a to 134 f) is equal to or less than the width W22 of the flat tubes 11 a to 11 f. Because of this, the longitudinal direction end surfaces of the flat tubes 11 a to 11 f can be placed in contact with the second member 133, and the positioning of the flat tubes 11 a to 11 f can be performed easily. That is, the flat tubes 11 a to 11 f can be easily secured in such a way that their longitudinal direction end surfaces are positioned in substantially the same position as the end surface of the second member 133 on the flat tube side of the second member 133 in the thickness direction of the second member 133. Further, because of this, spaces (that is, the intermediate flow paths 133 a to 133 f) can be easily formed between the first member 131 and the flat tubes 11 a to 11 f.
(6-4)
In the present embodiment, the width W3 of the intermediate flow path forming portions 134 a to 134 f is equal to or greater than the width W2 of the sections of the flat tubes 11 a to 11 f in which the refrigerant flow paths 112 are formed. Because of this, the width W1 of the refrigerant connection flow paths 231 a to 231 f can be set to the minimum dimension necessary for the refrigerant to travel through, and the pressure-resistant strength of the first header 13 improves.
(6-5)
In the present embodiment, the flat tube holding member 132 covers the second member 133 from outside, and both ends of the flat tube holding member 132 are in contact with and joined by brazing to the first member 131.
Here, the second member 133 can be easily secured by the flat tube holding member 132.
Further, in the present embodiment, the inwardly bent end portions of the flat tube holding member 132 are positioned in the recessed portion spaces S formed by the first portion 331 a and the second portion 331 b of the first member 131.
Here, because the recessed portion spaces S are formed by the first portion 331 a and the second portion 331 b of the first member 131, the securing of the flat tube holding member 132 can be performed easily.
(6-6)
In the present embodiment, clad metal different from other members (the flat tube holding member 132) is used for the second member 133. Specifically, the clad metal used for the second member 133 has a higher melting point than that of the clad metal used for other members.
This is to ensure that the brazing filler metal of the second member 133 does not flow to the end surfaces of the flat tubes 11 a to 11 f when joining together the second member 133 and the flat tube holding member 132 because the end surfaces of the flat tubes 11 a to 11 f are positioned between the second member 133 and the flat tube holding member 132. Therefore, brazing filler metal clogs in the refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f can be suppressed.
(6-7)
In the present embodiment, the first member 131, the second member 133, and the flat tube holding member 132 are configured from clad metal, so it is not necessary to use separate brazing filler metals when a constructor brazes these. Therefore, the number of man-hours in the brazing work can be reduced and costs can be suppressed.
(6-8)
In the present embodiment, the length L1, in the direction orthogonal to the longitudinal direction of the first member 131, of the refrigerant main flow path forming portion 13 a forming the refrigerant main flow path 131 a with which the flow dividing ability becomes higher can be easily arrived at from equality 1 above. Specifically, L1 with which the flow dividing ability becomes higher is arrived at by deriving, from the graph shown in FIG. 9, the values of the constants C₁and C₂with which the flow dividing ability becomes higher.

(7) Modifications

(7-1) Modification 1A

An embodiment of the present invention has been described above on the basis of the drawings, but the specific configurations thereof are not limited to those in the above-described embodiment and can be changed without departing from the gist of the invention.
FIG. 10 is a longitudinal cross-sectional view showing the flat tube holding member 132 pertaining to a modification.
In the above-described embodiment, only the flat tube-use holes 132 a to 132 f are formed in the flat tube holding member 132, but the present invention is not limited to this.
In addition to the flat tube-use holes 132 a to 132 f, plural holes 232 a to 232 e may also be formed in the flat tube holding member 132.
Here, although it is not mentioned above, when joining together the flat tube holding member 132 and the flat tubes 11 a to 11 f and joining together the flat tube holding member 132 and the second member 133, a flux is applied and thereafter these are connected by brazing or the like. Therefore, when performing the brazing, it is assumed that the flux will volatilize.
Therefore, by forming the plural holes 232 a to 232 e in the flat tube holding member 132, it becomes easier to remove volatilized gas, so airtightness between the flat tube holding member 132 and the flat tubes 11 a to 11 f and between the flat tube holding member 132 and the second member 133 can be ensured.

(7-2) Modification 1B

In the above-described embodiment, the second member 133 is described as being disposed between the first member 131 and the flat tube holding member 132, but the present invention is not limited to this and the second member 133 does not have to be disposed. That is, a configuration in which the end surface of the first member 131 on the flat tube holding member side and the end surface of the flat tube holding member 132 on the first member side are in contact with each other may also be employed.
In modifications 1C to 1G below, employable configurations of the headers 13 and 14 (below, only the first header 13 is indicated) and the flat tubes 11 a to 11 f in this case will be described.

(7-3) Modification 1C

FIG. 11 is a plan view, pertaining to the present modification 1C, of the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member has been removed. FIG. 12 is a side view, pertaining to the present modification 1C. of the first member 131 as seen from the side of the flat tubes 11 a to 11 f.
In the heat exchanger 1 pertaining to the present modification 1C, as shown in FIG. 11 and FIG. 12, a recessed portion 234 a that is inwardly recessed across the vertical direction of the first member 131 is formed in the end portion of the first member 131 on the flat tube holding member side. The recessed portion 234 a functions as the intermediate flow paths 133 a to 133 f of the above-described embodiment. That is, a recessed portion forming portion 234 forming the recessed portion 234 a corresponds to the intermediate flow path forming portions 134 a to 134 f of the above-described embodiment.
In the heat exchanger 1 pertaining to the present modification 1C, even in a case where the second member 133 is not disposed between the first member 131 and the flat tube holding member 132, effects that are the same as those of the above-described embodiment can be expected because the recessed portion 234 a having the function of the intermediate flow paths 133 a to 133 f is formed in the first member 131. Further, a width W31 of the recessed portion forming portion 234 is, like in the above-described embodiment, equal to or less than the width W22 of the flat tubes 11 a to 11 f, so when connecting the flat tubes 11 a to 11 f to the headers 13 and 14, the longitudinal direction end surfaces of the flat tubes 11 a to 11 f come into contact with the first member (specifically, the periphery of the recessed portion forming portion 234). Because of this, the positioning of the flat tubes 11 a to 11 f can be performed easily.

(7-4) Modification 1D

FIG. 13 is a plan view, pertaining to the present modification 1D, of the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member has been removed. FIG. 14 is a side view, pertaining to the present modification 1D, of the first member 131 as seen from the side of the flat tubes 11 a to 11 f.
In the heat exchanger 1 pertaining to the present modification 1D, as shown in FIG. 14, recessed portions 254 a to 254 f that are inwardly recessed are formed in the end portion of the first member 131 on the flat tube holding member side only in positions corresponding to the height positions of the flat tubes 11 a to 11 f (specifically, substantially the same height positions). That is, in the first member 131 pertaining to the present modification 1D, plural recessed portions 254 a to 254 f are formed. The recessed portions 254 a to 254 f function as the intermediate flow paths 133 a to 133 f of the above-described embodiment. That is, recessed portion forming portions 244 a to 244 f forming the recessed portions 254 a to 254 f correspond to the intermediate flow path forming portions 134 a to 134 f of the above-described embodiment.
Therefore, in the heat exchanger 1 pertaining to the present modification 1D, even in a case where the second member 133 is not disposed between the first member 131 and the flat tube holding member 132, effects that are the same as those of the above-described embodiment can be expected because the recessed portions 254 a to 254 f having the function of the intermediate flow paths 133 a to 133 f are formed in the first member 131. Further, a width W32 of the recessed portion forming portions 244 a to 244 f is equal to or less than the width W22 of the flat tubes 11 a to 11 f, so effects that are the same as those of modification 1C are also achieved.

(7-5) Modification 1E

FIG. 15 is a plan view, pertaining to the present modification 1E, of the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member has been removed.
In the heat exchanger 1 pertaining to the present modification 1E, as shown in FIG. 15, recessed portions that are inwardly recessed are formed in the end portions of the flat tubes 11 a to 11 f on the first member side (in FIG. 15, of the recessed portions formed in the flat tubes 11 a to 11 f, only a recessed portion 265 a formed in the flat tube 11 a is shown). The recessed portions function as the intermediate flow paths 133 a to 133 f of the above-described embodiment. That is, recessed portion forming portions forming the recessed portions (in FIG. 15, of the recessed portion forming portions formed in the flat tubes 11 a to 11 f, only a recessed portion forming portion 255 a formed in the flat tube 11 a is shown) correspond to the intermediate flow path forming portions 134 a to 134 f of the above-described embodiment.
In the heat exchanger 1 pertaining to the present modification 1E, even in a case where the second member 133 is not disposed between the first member 131 and the flat tube holding member 132, effects that are the same as those of the above-described embodiment can be expected because the recessed portions having the function of the intermediate flow paths 133 a to 133 f are formed in the flat tubes 11 a to 11 f. Further, a width W33 of the recessed portion forming portions is, like in the above-described embodiment, equal to or less than the width W22 of the flat tubes 11 a to 11 f. Therefore, when connecting the flat tubes 11 a to 11 f to the headers 13 and 14, the longitudinal direction end surfaces of the flat tubes 11 a to 11 f come into contact with the first member 131. Because of this, the positioning of the flat tubes 11 a to 11 f can be performed easily.

(7-6) Modification 1F

FIG. 16 is a plan view, pertaining to the present modification 1F, of the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member has been removed.
In the heat exchanger 1 pertaining to the present modification 1F, as shown in FIG. 16, both longitudinal direction end portions of the flat tubes 11 a to 11 f have convex shapes as seen in a plan view. Specifically, the flat tubes 11 a to 11 f have corner portions (in FIG. 16, only a corner portion 121 a of the flat tube 11 a is shown) cut squarely as seen in a plan view. The outer surfaces of the corner portions of the flat tubes 11 a to 11 f are in contact with the flat tube holding member 132 (specifically, the outer surfaces of the corner portions of the flat tubes 11 a to 11 f are in contact with the outer surface of the flat tube holding member 132 and the inner surfaces of the sections forming the flat tube-use holes 132 a to 132 f).
Further, the corner portions of the flat tubes 11 a to 11 f are formed in such a way that, in a state in which the outer surfaces of the corner portions of the flat tubes 11 a to 11 f are in contact with the flat tube holding member 132, a space S1 is formed between the flat tube holding member 132, the flat tubes 11 a to 11 f, and the first member 131. Additionally, this space S1 functions as the intermediate flow paths 133 a to 133 f of the above-described embodiment. A longitudinal direction width W34 of the space S1 (that is, the distance between sections 332 of the flat tube holding member 132 that form the space S1) is smaller than the width W22 of the flat tubes 11 a to 11 f.
As described above, in the heat exchanger 1 pertaining to the present modification 1F, even in a case where the second member 133 is not disposed between the first member 131 and the flat tube holding member 132, effects that are the same as those of the above-described embodiment can be expected because the space S1 functions as the intermediate flow paths 133 a to 133 f. Further, the positioning of the flat tubes 11 a to 11 f can be performed easily.

(7-7) Modification 1G

FIG. 17 is a plan view, pertaining to the present modification 1G of the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member has been removed.
In the heat exchanger 1 pertaining to the present modification 1G, as shown in FIG. 17, convex portions 171 are formed on both width direction end portions of both longitudinal direction end portions of the flat tubes 11 a to 11 f. The outer surfaces of the convex portions 171 opposing the flat tube holding member 132 are in contact with the flat tube holding member 132 in a state in which the flat tubes 11 a to 11 f are positioned in their regular positions. The convex portions 171 are formed in positions such that a space S2 is formed between the flat tube holding member 132, the flat tubes 11 a to 11 f, and the first member 131 in a state in which the flat tubes 11 a to 11 f are positioned in their regular positions. The space S2 functions as the intermediate flow paths 133 a to 133 f of the above-described embodiment. In this state, a longitudinal direction width W35 of the space S2 is the same as the width W22 of the flat tubes 11 a to 11 f.
As described above, in the heat exchanger 1 pertaining to the present modification 1G, because of the convex portions 171, the positioning of the flat tubes 11 a to 11 f can be performed easily and effects that are the same as those of the above-described embodiment are also achieved.

(7-8) Modification 1H

In the above-described embodiment, the length, in the direction orthogonal to the longitudinal direction of the headers 13 and 14, of the refrigerant main flow path forming portions forming the refrigerant main flow paths in the headers 13 and 14 is the same from the upper ends to the lower ends of the headers 13 and 14, but the present invention is not limited to this.
For example, the length of the header through which liquid refrigerant flows may also be made smaller than the length of the header through which gas refrigerant flows. Because of this, a drop in the refrigerant flow speed of the liquid refrigerant can be suppressed and the flow dividing ability can be improved.

Second Embodiment

Next, a second embodiment will be described. In the description below, the same reference signs will be given to components and so forth that are the same as those in the first embodiment and description will be omitted.
That which mainly differs in the second embodiment from the first embodiment is that a securing member 210 for more stably securing the flat tubes 11 a to 11 f is interposed between the flat tube holding member 132 and the second member 133. Therefore, the securing member 210 will be described below.

(1) Securing Member 210

FIG. 18 is a plan view of the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member has been removed. FIG. 19 is a longitudinal cross-sectional view in a case where the first header 13 and the flat tubes 11 a to 11 f in a case where the upper end member and the lower end member have been removed are cut along line XIX-XIX shown in FIG. 18. FIG. 20 is a longitudinal cross-sectional view in a case where the securing member 210 is cut along line XX-XX shown in FIG. 18.
As shown in FIG. 18 and FIG. 19, the securing member 210 is sandwiched between the flat tube holding member 132 and the second member 133. Further, the securing member 210 has the role of securing the end portions of the plural flat tubes 11 a to 11 f together with the flat tube holding member 132. The securing member 210 is configured from a metal member such as clad metal and has a long and narrow flat panel shape extending in the vertical direction.
As shown in FIG. 20, plural flat tube securing holes 210 a to 210 f having long and narrow shapes in the width direction of the securing member 210 are formed in the securing member 210 at predetermined intervals apart from each other along the longitudinal direction of the securing member 210. Specifically, the flat tube securing holes 210 a to 210 f are formed by flat tube securing hole forming portions 220 a to 220 f of the securing member 210. The flat tube securing hole forming portions 220 a to 220 f have projecting portions 230 a to 230 f at which both height direction edges of each of the flat tube securing hole forming portions 220 a to 220 f become closer to each other. A height direction length H2 of the spaces formed by the projecting portions 230 a to 230 f is smaller than the thickness of the flat tubes 11 a to 11 f. Because of this, the flat tubes 11 a to 11 f are held. The flat tube securing holes 210 a to 210 f are formed by stamping.
The method of manufacturing the heat exchanger 1 of the second embodiment is substantially the same as that of the first embodiment simply as a result of adding, to the process of the method of manufacturing the heat exchanger 1 of the first embodiment, forming the securing member 210, joining together the second member 133 and the securing member 210, and joining together the securing member 210 and the flat tube holding member 132.

(2) Characteristics

(2-1)
In the second embodiment, by interposing the securing member 210 between the flat tube holding member 132 and the second member 133, the flat tubes 11 a to 11 f can be more stably secured. Further, by interposing the securing member 210, the sections of the flat tubes 11 a to 11 f inserted into the first header 13 can be changed in the range of the thickness of the securing member 210. Therefore, when joining together the first header 13 and the flat tubes 11 a to 11 f, inflow of the brazing filler metal from the second member 133 into the refrigerant flow paths 112 formed in the flat tubes 11 a to 11 f can be suppressed.
(2-2)
The securing member 210 has a flat panel shape as described above. Because of this, the flat tube securing holes 210 a to 210 f can be easily formed in the securing member 210. Therefore, it is easy for a constructor to execute construction.
(2-3)
The flat tube holding member 132 in the second embodiment covers the securing member 210 from outside in addition to the second member 133, so not just the second member 133 but also the securing member 210 can be easily secured.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a variety of heat exchangers configured from headers that extend in a vertical direction and plural flat tubes that extend in a direction orthogonal to the length of the headers and are inserted into the headers.

REFERENCE SIGNS LIST

1 Heat Exchanger
11 a to 11 f Flat Tubes
13, 14 Headers
112 Refrigerant Flow Paths in Flat Tubes
131 First Member
131 a Refrigerant Main Flow Path (Main Flow Path)
132 Flat Tube Holding Member
133 Second Member
133 a to 133 f Intermediate Flow Paths
210 Securing Member
231 a to 231 f Refrigerant Connection Flow Paths
W1 Width of Refrigerant Connection Flow Paths
W2 Width of Sections of Flat Tubes in Which Refrigerant Flow Paths are Formed
W3 Width of Intermediate Flow Paths

CITATION LIST

Patent Literature

Patent Citation 1: JP-A No. 2006-284133

Claims

1. A heat exchanger comprising:

a pair of headers extending in an up-and-down direction, the pair of headers being configured to carry a refrigerant flow therein; and

plural flat tubes connected to the headers at different height positions, the plural flat tubes extending along a direction intersecting a longitudinal direction of the headers,

each of the headers including

a first member having a main flow path extending in the up-and-down direction and configured to carry the refrigerant flow therein, and refrigerant connection flow paths extending from the main flow path to an end surface in the direction intersecting the longitudinal direction in order to circulate the refrigerant flow between the main flow path and plural refrigerant flow paths formed in the flat tubes, and

a flat tube holding member with end portions of the flat tubes adhered thereto, the flat tube holding member holding the flat tubes, and

intermediate flow paths interconnecting the refrigerant connection flow paths and the plural refrigerant flow paths in the flat tubes, the intermediate flow paths being formed in at least one of

the headers and

the flat tubes.

2. The heat exchanger according to claim 1, wherein

a width of the intermediate flow paths is no more than a width of the flat tubes.

3. The heat exchanger according to claim 1, wherein

each of the headers further includes a second member sandwiched between the first member and the flat tube holding member, and

in a case where the intermediate flow paths are at least partially formed in the headers, the intermediate flow paths are at least partially formed in the second member.

4. The heat exchanger according to claim 1, wherein

in a case where

L1 is a length in a direction orthogonal to a longitudinal direction of the first member of a main flow path forming portion forming the main flow path,

π is pi,

g is a gravitational acceleration,

m is a circulating volume of refrigerant in a gas-liquid two-phase state flowing through the main flow path,

x is an inlet quality, the inlet quality being a ratio of a mass flow rate of the refrigerant in a gas-phase state with respect to a total mass flow rate of the refrigerant in a gas-liquid two-phase state inside an inlet header of the pair of headers, the refrigerant flows from outside into the inlet header,

ρ_Gis a density of the refrigerant in a gas-phase state flowing through the main flow path,

D is a distance between the uppermost flat tube and a lowermost flat tube, and

C₁and C₂are constants,

a relationship

\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}

holds true, and

C₁=0.16 and C₂=1.5.

5. The heat exchanger according to claim 1, wherein

in a case where

π is pi,

g is a gravitational acceleration,

D is a distance between the uppermost flat tube and a lowermost flat tube, and

C₁and C₂are constants,

a relationship

\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}

holds true, and

C₁=0.24 and C₂=1.1.

6. The heat exchanger according to claim 3, further comprising

a securing member sandwiched between the flat tube holding member and the second member, the securing member securing the end portions of the plural flat tubes together with the flat tube holding member.

7. The heat exchanger according to claim 3, wherein

the second member has a flat panel shape.

8. The heat exchanger according to claim 3, wherein

the flat tube holding member covers the second member, and both ends of the flat tube holding member are in contact with and brazed to the first member.

9. The heat exchanger according to claim 1, wherein

plural holes are formed in the that tube holding member.

10. The heat exchanger according to claim 1, wherein

a length in a direction orthogonal to a longitudinal direction of the first member, of a main flow path forming portion forming the main flow path, is smaller than a width of the flat tubes.

11. The heat exchanger according to claim 2, wherein

12. The heat exchanger according to claim 2, wherein

in a case where

π is pi,

g is a gravitational acceleration,

D is a distance between the uppermost flat tube and a lowermost flat tube, and

C₁and C₂are constants,

a relationship

\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}

holds true, and

C₁=0.16 and C₂=1.5.

13. The heat exchanger according to claim 2, wherein

in a case where

π is pi,

g is a gravitational acceleration,

m is a circulating volume of refrigerant in a gas-liquid-phase state flowing through the main flow path,

D is a distance between the uppermost flat tube and a lowermost flat tube, and

C₁and C₂are constants,

a relationship

\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}

holds true, and

C₁=0.24 and C₂=1.1.

14. The heat exchanger according to claim 3, wherein

in a case where

π is pi,

g is a gravitational acceleration,

D is a distance between the uppermost flat tube and a lowermost flat tube, and

C₁and C₂are constants,

a relationship

\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}

holds true, and

C₁=0.16 and C₂=1.5.

15. The heat exchanger according to claim 3, wherein

in a case where

π is pi,

g is a gravitational acceleration,

D is a distance between the uppermost flat tube and a lowermost flat tube, and

C₁and C₂are constants,

a relationship

\frac{4}{C_{2} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}} \leq L 1^{2} D^{0.5} \leq \frac{4}{C_{1} \cdot π} \frac{m \cdot x}{ρ_{G} g^{0.5}}

holds true, and

C₁=0.24 and C₂=1.1.

16. The heat exchanger according to claim 6, wherein

the second member and the securing member have flat panel shapes.

17. The heat exchanger according to claim 6, wherein

the flat tube holding member covers one of

the second member and

the second member and the securing member

from outside, and

both ends of the flat tube holding member are in contact with and brazed to the first member.

18. The heat exchanger according to claim 7, wherein

the flat tube holding member covers one of

the second member and

the second member and the securing member

from outside, and