JPH08145580A - Heat exchanger - Google Patents

Abstract

PURPOSE: To reduce internal pressure loss and improve heat exchanging efficiency by a method wherein a flat tube is bent in the widthwise direction of the tube at a proper place in the lengthwise direction of the same while the bent part is twisted to produce a twisted bent part. CONSTITUTION: A flat tube l is bent so as to obtain a U-shape bent part in the widthwise direction of the tube 1 at the intermediate part in the lengthwise direction of the tube 1 while the bent part is twisted by a predetermined angle with respect to the straight tube type parts of both sides 2, 3 to constitute a twisted bent part 4. The twisting angle or an angle at the twisted and bent part 4 with respect to the straight tube type parts 2, 3 is set so as to be an angle slightly smaller than 90 deg., for example. Under this state, the twisted and bent parts 4 of neighboring tubes 1 are retained while being abutted against each other under superposed and engaged arranging condition mutually. According to this method, an internal pressure loss can be reduced and a heat exchanging rate can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used as an evaporator, a condenser or the like in a car air conditioning system, a room air conditioning system or the like, and in particular, a heat exchange tube is bent at an appropriate position in its longitudinal direction. Type heat exchanger.

[0002]

2. Description of the Related Art Recently, for example, as an evaporator or a condenser in a car air-conditioning system, a plurality of straight tubular flat tubes arranged in parallel with each other at a predetermined interval in the thickness direction. A so-called multi-flow or parallel-flow type heat exchanger having a pair of hollow headers arranged at both ends of the tube and having tube ends communicated with each other has been widely used.

This type of heat exchanger is for exchanging heat between a heat exchange medium flowing through the inside thereof and air passing through an air circulation gap formed between adjacent tubes. In response to a request for further improvement of the water vapor, the convenience of treatment of condensed water, or the downsizing according to the installation location, for example, as disclosed in Japanese Patent Application Laid-Open No. 63-28490 (Japanese Patent Application Publication), A bent heat exchanger having a structure in which each of the flat tubes, which is a constituent member of the exchanger, is bent in the tube width direction at an intermediate portion in the longitudinal direction is known.

However, it is technically very difficult to bend the flat tube in the width direction without crushing the internal passage.

As a solution to this problem, US Pat. No. 5,279,360 and US Pat.
41,870,
It is also known that a large number of bending grooves are formed in advance on both side edges in the width direction of a planned bending portion so that bending work in the tube width direction can be easily performed.

According to this proposal, however, it is necessary to predetermine the bending portion of each flat tube and form bending grooves on both side edges of the flat tube.
Not only the number of working steps is increased, but also the bending portion is limited. In addition, the formation of the bending groove reduces the cross-sectional area of the passage at the bent portion and increases the internal pressure loss.

On the other hand, instead of the structure in which the flat tube is bent in the width direction as described above, Japanese Patent Laid-Open No. 4-1879.
As disclosed in Japanese Patent Application Publication No. 90 (Japanese Patent Application Publication No. 90), folding using a tube bent while being twisted so that the straight tubular portions on both sides of the planned bending portion are reversed from each other. A curved heat exchanger has been proposed.

In the heat exchanger according to this proposal, it is possible to avoid the disadvantage that the internal passage is crushed at the bent portion and the cross-sectional area of the internal passage is significantly reduced.

However, when manufacturing and assembling the heat exchanger, all the tubes must be bent and formed in advance as described above, and then the tubes and the header must be assembled. It was troublesome. In addition, a perforated flat tube is used as the flat tube, and the tube is bent and formed as described above, and the air passing through the air flow gap between the straight tube portions of one of the tubes is passed between the straight tube portions of the other. In the case of a heat exchanger that passes through the air circulation gap, the windward unit passage in one straight tubular portion of each flat tube constitutes the windward unit passage in the other straight tubular portion. Become. Therefore, there is a problem in that the heat exchange efficiency is different between the unit passages of the flat tube, and the heat exchange efficiency is deteriorated as a whole.

In view of the problems of the prior art, the present invention has a plurality of flat tubes arranged in parallel to each other at a predetermined interval in the thickness direction, and tube ends arranged at both ends of the tubes. Although it is a bent heat exchanger having a pair of headers connected in communication with each other and bent in the tube width direction at an appropriate portion in the longitudinal direction of the tube, its manufacture can be easily performed and the internal pressure It is an object of the present invention to provide a heat exchanger with low loss and excellent heat exchange efficiency.

[0011]

To achieve the above object, the present invention is directed to a plurality of flat tubes arranged in parallel with each other at a predetermined interval in the thickness direction, and tube ends arranged at both ends of the tubes. The tube comprises a pair of hollow headers connected in communication with each other, and each of the tubes is bent and formed in the tube width direction at an appropriate position in the longitudinal direction, and the bent parts are formed with respect to the straight tubular parts on both sides thereof. A heat exchanger characterized by comprising a twisted bent portion provided with a twist of a predetermined angle, further comprising fins arranged between adjacent straight tubular portions. It is a summary.

For the purpose of facilitating the manufacture of the heat exchanger and improving the strength of the entire heat exchanger, the heat exchanger is further provided between the adjacent straight tubular portions and outside the outermost tube. Arranged fins, tube insertion holes corresponding to each of the tubes are provided in a row, an intermediate strip plate-shaped portion in which the boundary portion between the straight tubular portion and the twisted bent portion of each tube is inserted into the insertion hole, A strip plate shape having an outer strip plate portion that is bent and extended from both ends of the intermediate strip plate portion, and is integrally joined to a fin arranged outside the outermost tube in a juxtaposed arrangement state. It may be provided with a reinforcing plate.

Further, in order to improve the strength of the heat exchanger on the side of the twisted bent portion, the adjacent twisted bent portions may be brought into contact with each other in an overlapping state.

[0014]

The flat tubes are bent in the tube width direction at appropriate places in the longitudinal direction, and the bent portions are twisted at a predetermined angle with respect to the straight tubular portions on both sides thereof. This is what constitutes the bending part.

With this configuration, when the twisted bent portion of the flat tube is processed, a plurality of straight tubular flat tubes are arranged in parallel in the thickness direction at predetermined intervals, and a pair of headers is provided at both ends thereof. All tubes are simultaneously bent in the tube width direction at appropriate points in the longitudinal direction of the tube in a state in which they are arranged and the tube ends are connected in communication with the header. On the other hand, a twist bending process that imparts a twist of a predetermined angle may be performed. As a result, the processing of the twisted bent portion of each tube is technically very easily performed.

Further, tube insertion holes corresponding to the respective tubes are provided in a row, and an intermediate strip plate-shaped portion in which a boundary portion between the straight tubular portion and the twisted bent portion of each tube is inserted into the insertion hole, and the intermediate portion. A strip plate-shaped reinforcing plate that is bent and extends from both ends of the strip plate portion, and has outer strip plate portions that are integrally joined to fins arranged outside the outermost tube in a juxtaposed arrangement state. In the case of the one provided with, the influence of twisting, bending, etc. on the straight tubular portion is less likely to occur during the above-mentioned twist bending process. Therefore, the twist bending process can be performed easily and reliably with a smaller radius of curvature.
Moreover, the presence of the reinforcing plate improves the strength of the entire heat exchanger.

When the twisted bent portions of adjacent tubes are brought into contact with each other in a state of being overlapped with each other, the strength on the twisted bent portion side is improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The heat exchanger according to the present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) FIGS. 1 to 16 show an embodiment applied to an evaporator for a car air conditioning system.

In the heat exchanger shown in FIG. 1, (1)
Is a flat tube for heat exchange. As shown in FIG. 10, each flat tube (1) has an elliptical cross-section outer peripheral shape, and has a plurality of connecting walls (1b) connecting the upper and lower planar walls (1a) (1a) therein. The tubes are arranged side by side in the width direction, and the inside of the tube is divided into a plurality of unit passages (1c).

The flat tube (1) is a so-called harmonica tube made of aluminum extruded material.
However, in the present invention, instead of the harmonica tube made of the extruded material as described above, a corrugated fin may be inserted and arranged in an electric resistance welded tube having a flat cross section, or other known structure. It may be one.

As shown in FIGS. 1 and 2, the flat tube (1) is bent in the tube width direction at the middle portion in the longitudinal direction, and the bent portions are straight tubular portions on both sides thereof. (2) The twisted bent portion (4) is provided with a twist of a predetermined angle with respect to (3). In this embodiment, the flat tube (1) is bent and formed in a U-shape at the twisted bent portion (4) so that the straight tubular portions (2) and (3) are parallel to each other at a predetermined interval. Has been done.

In addition to the U-shaped bending, the both straight tubular portions (2) and (3) are bent at a predetermined angle, for example, V-shaped. It may be. The point is that the straight tubular portions (2) and (3) are bent and formed so as to form a predetermined angle with each other.

Further, the bent portion is not limited to the middle portion in the longitudinal direction of the tube (1) as in the embodiment, as long as it is located at an appropriate position in the longitudinal direction.

Particularly, as shown in FIG. 6, the twisted bent portion (4) has an outer edge side thereof at the straight tubular portion (2).
It is formed by twisting so as to be substantially parallel to (3).

The twist angle, that is, the angle θ formed by the twisted bent portion (4) with respect to the straight tubular portions (2) and (3).
Is set to be slightly below 90 °.

The twisted and bent portion (4) is usually set as short as possible in consideration of the limit of twisting and bending, and the whole is usually formed in a curved arc shape. The bent shape and radius of curvature are not particularly limited as long as the inner passage of the tube (1) is not crushed and the passage cross-sectional area is not narrowed.

The U-shaped flat tubes (1) formed by twisting and bending as described above have their twisted and bent portions (4) arranged downward and the straight tubular portions (2) and (3). In a vertical arrangement, the flat tubes (1) are arranged in parallel at a predetermined interval in the left-right direction, and the hollow headers (5) (6) made of aluminum communicate with the upper ends of the flat tubes (1). It is connected to the.

In this state, the twisted bent portions (4) of the adjacent tubes (1) are held in contact with each other in a fitting arrangement in which they overlap each other as shown in FIG. . As a result, the strength of the heat exchanger on the twisted and bent side is improved. The twisted bent portions (4) may be joined and integrated by brazing or the like to further improve the strength.

Between the straight tubular portions (2) located on the leeward side and outside the straight tubular portions (2) located on the outermost side, and between the straight tubular portions (3) also located on the leeward side, and between the straight tubular portions (3). Fins for improving heat exchange efficiency, for example, corrugated fins (11) (12) made of aluminum, are arranged on the outer side of the straight tubular portion (3) located on the outer side, and are integrated by brazing. . As shown in FIG. 2, the fin pitch of the leeward corrugated fin (11) is set relatively larger than that of the leeward corrugated fin (12).

Further, in the heat exchanger according to this embodiment, a pair of front and rear bands are provided so as to surround the group of straight tubular portions (2) on the leeward side and the group of straight tubular portions (3) on the leeward side. Plate-shaped reinforcing plates (13) and (14) are attached.

This strip-shaped reinforcing plate (13) (14)
Is a substantially upward U-shape in a front view, which is composed of an intermediate strip plate portion (15) and a pair of outer strip plate portions (16) (16) bent and extended from both ends thereof. It is a bent plate.

As shown in FIG. 7, in the intermediate strip plate-like portion (15), tube insertion holes (15a) corresponding to the respective flat tubes (1) are arranged in rows at predetermined intervals. The boundary portion between the straight tubular portions (2) and (3) and the twisted and bent portion (4) of each corresponding tube (1) is inserted through 15a) and integrated by brazing.

As shown in FIG. 1, the outer strip-shaped portions (16) (16) are arranged in a juxtaposed state with fins (11) (12) arranged outside the outermost tube (1). Is
It is integrated with brazing. In order to facilitate the above brazing, it is desirable to use, as the reinforcing plate, one having a brazing material layer coated on one surface or both surfaces of the core material.

By mounting the reinforcing plates (13) and (14), not only the strength of the core portion of the heat exchanger can be improved, but also the tube to be described later is twisted or twisted to other portions at intended limited portions. Torsional bending can be performed without adverse effects such as bending.

The reinforcing plates (13) (14)
The intermediate strip plate portion (15) may be provided with a drainage hole (15b) and / or a drainage gutter (15c) as shown in FIG. 13 so that condensed water does not easily accumulate.

The headers (5) and (6) are formed by cylindrically molding a brazing sheet made of aluminum in which both sides or one side of a core material is coated with a brazing material layer, and the abutting edges (5a) ( 6a) A sushi is electric resistance welded. As shown in FIG. 2, the headers (5) and (6) have a so-called kamaboko shape in which the tube insertion side peripheral surface is formed flat and the opposite side peripheral surface is formed in an arc. It is supposed to be presented. Such a cross-sectional shape is inferior to the one having a circular cross-section in terms of pressure resistance, but in the case of an evaporator, it is not required to have pressure resistance as high as that of a condenser. It can withstand pressure sufficiently.

The cross-sectional shapes of the headers (5) and (6) are so-called kamaboko shapes as described above for the following reason.
That is, when the header has a circular cross-section, when the flat tube (1) is inserted and connected from the tube insertion hole formed in the header in the circumferential direction, the tube end portion reaches the approximate center axis of the header. The effective core area is reduced because it must be inserted. On the other hand, when the header (5) (6) has a flat peripheral surface on the tube end insertion side as in the above-described embodiment, the insertion amount of the tube end is small, and the header is effective. This is because the core area can be increased.

For the same reason, the header (5)
As shown in FIG. 11, the sectional shape of (6) may be an elliptical sectional shape on the tube insertion side and a circular sectional shape on the opposite side. In addition, as shown in FIG. 12, the baffle member (10) is inserted and arranged in the headers (5) and (6) so as to be positioned between the adjacent tubes from the peripheral surface on the opposite side of the tube insertion side, so that the heat exchange medium is disposed. May be efficiently divided into each tube (1). The baffle plate (10) is composed of an outer peripheral edge portion (10a) which is attached to the outer peripheral surfaces of the headers (5) and (6) and a baffle plate (10b) which protrudes inward from the inner peripheral surface thereof. It is a thing.

Therefore, as shown in FIG. 1, the heat exchange medium fed from the inlet pipe (7) connected to the end of the hollow header (6) located on the leeward side is indicated by an arrow. As described above, the flat tubes (1) are circulated in a U shape, flow into the hollow header (5) on the windward side, and the outlet pipe (8) is connected to the end of the header (5) for communication. Sent out from. In this way, the heat exchange medium flowing through the flat tube (1) exchanges heat with the air (white arrow) flowing through the heat exchanger in the front-rear direction.

However, as shown in FIG. 14, the inlet pipe (7) and the outlet pipe (8) may be provided on the same end side of both the headers (5) and (6). This arrangement allows the heat exchange medium to flow in and out from the same side of the heat exchanger. In addition, in the header (6) on the entrance side,
The inner pipe (60) having a plurality of holes (60a) for branching the heat exchange medium is coaxially arranged, and the inlet pipe (7) is connected for communication so as to promote the diversion of the heat exchange medium to each tube. May be.

The heat exchanger having the above structure is manufactured, for example, as follows.

That is, as shown in FIG. 8 (a), straight flat tubes (1) made of aluminum extruded material are arranged parallel to each other at a predetermined interval in the thickness direction. Then, as shown in FIG. 8B, the tube (1)
The strip-shaped reinforcing plates (13) and (14) are inserted and arranged from both sides. As shown in FIG. 8C, the headers (5) and (6) are connected to both ends of the tube (1) so that the tubes (1) are connected to each other and the outermost tube (1) and the outer side of the tube (1) are connected to each other. The corrugated fins (11) and (12) are loaded between the strip plate portion (16). In addition, with the necessary brazing parts assembled, this heat exchanger assembly is collectively brazed to join and integrate the whole.

As shown in FIG. 9, the heat exchanger integrally brazed and joined in this manner is bent in the tube width direction at the longitudinal intermediate portion of the tube (1) to form the tube (1). The straight tubular parts should be parallel to each other. At the time of forming the bend, a force may be applied in the twisting direction by using an appropriate jig so that all the planned bending portions of the tubes (1) are twisted in the same direction. As described above, the heat exchanger having the refraction structure is obtained.

As is clear from the above description, each tube (1) is bent in the tube width direction at an appropriate position in the longitudinal direction, and the bent parts are formed on the straight tubular portions on both sides thereof. Since the twisted bent portion (4) is given a twist of a predetermined angle, in the processing of the twisted bent portion (4), the flat tube (1) is bent at the planned bending portion. In the tube width direction, it may be formed by bending it at the same time, or in tandem therewith, and the bending portion may be twisted to impart a predetermined angle of twist to the straight tubular portions on both sides thereof. Division (4)
Can be formed very easily in terms of processing technology.

Particularly, in the structure in which the flat tube (1) has a U-shaped bending like the heat exchanger shown in the above embodiment,
The radius of curvature of the twisted bent portion (4) needs to be machined to a very small one, but the twisted bent structure (4) having such a small radius of curvature is machined by adopting the above-described twisted bending structure. Is technically very easy to carry out.

Furthermore, the straight tubular portion (2) of the tube (1)
In the heat exchanger for an evaporator in which the side edges in the width direction of (3) face each other in the front-back direction, the fins (1
1) The fin pitch of ... is large, and the leeward fins (1
Since the structure in which the fin pitch of 2) is set small is adopted, the heat exchange performance as the evaporator can be improved.

In the manufacture of the heat exchanger, the flat heat exchanger is assembled and then the flat tubes (1) are collectively bent to manufacture the refraction heat exchanger. Therefore, the heat exchanger can be manufactured with high productivity.

In the above embodiment, the heat exchange medium that has flowed into the leeward header (6) is shunted to all the tubes (1) that are communicatively connected to the header (6) and then flows into the windward header (5). The so-called one-pass type is shown, but a partition member for partitioning the inside in the longitudinal direction is arranged in the headers (5) and (6) to allow the heat exchange medium to flow in the heat exchanger. It may be a so-called multi-pass type heat exchanger that flows in a meandering shape.

However, in the case of the heat exchanger as the evaporator having the structure as shown in this embodiment, the one-pass type is excellent in heat exchange performance. For the purpose of clarifying this point, a performance comparison was made between the one-pass evaporator and the two-pass evaporator.

As the sample, the evaporator having the structure shown in the above-mentioned embodiment, and the core size: height 23
5 x width 258 mm, effective core size: height 178 x width 2
59 mm, effective core area: 0.046 m ² , tube pitch: 11.7 mm, fins: width 22 x height 10 mm,
The fin pitch: 1.1 mm and the number of tubes: 21 were set respectively. For a 2-pass evaporator, the number of tubes was 10 in the first pass and 10 in the second pass. The one provided with a partition member so as to be 11 pieces was adopted. The test conditions were as follows: heat exchange medium: HFC134a, heat exchange medium temperature before expansion valve: 53.
5 ° C, inlet air dry bulb temperature: 27 ° C, outlet air wet bulb temperature:
Exchange heat (kca) at 19.5 ° C., SH: 5 deg
(l / h) and the outlet pressure (kg / cm ² ) of the evaporator are shown in Fig. 15, and the heat exchange medium side pressure loss (kg /
The relationship between cm ² ) and the same medium flow rate (kg / h) is shown in FIG. As is clear from the result, it can be seen that the one-pass type evaporator is superior to the two-pass type evaporator in both the heat exchange amount and the pressure loss.

(Second Embodiment) FIGS. 17 to 21 show an embodiment in which the present invention is applied to an evaporator for a car air conditioning system, as in the above embodiments.

The evaporator according to this embodiment is substantially the same as the above embodiment, but differs in the cross-sectional shape of the header, the presence or absence of the reinforcing plate, the shape of the twisted bent portion, and the like. Therefore, here, the points different from the above embodiment will be described.

Tube (1) that constitutes this heat exchanger
Is twisted so that the twisted bent portion (4) forms an angle of 90 degrees with the straight tubular portions (2) (3) on both sides of the twisted bent portion (4) and the adjacent twisted bent portions (4) and the like. It differs from the above-described embodiment in that the axes are arranged in a spaced manner as shown in FIG.

Further, the headers (5) and (6) are different from the above-mentioned embodiments in that the headers (5) and (6) have a circular cross section in order to further improve the pressure resistance.

The heat exchanger according to this embodiment is not equipped with the strip-shaped reinforcing member as shown in the above embodiment.

Further, as shown in FIG. 19, the tube (1) is preliminarily twist-molded as described above and the tube (1) is used to manufacture the heat exchanger as shown in FIG. This is done by forming the assembly and then bending the heat exchanger assembly as shown in FIG. However, also in this heat exchanger, the tube may be twisted and bent in the same manner as in the above embodiment.

The other parts of the configuration are the same as those of the above-mentioned embodiment, and the corresponding parts are designated by the same reference numerals and the description thereof is omitted.

(Third Embodiment) FIGS. 22 and 23 show an embodiment in which the present invention is applied to a condenser for a car air conditioning system.

The condenser according to this embodiment has the header (5) of the heat exchanger having the structure shown in the first embodiment.
(6) is the vertical direction, the straight tubular portion (2) of the tube (1)
(3) is arranged in the horizontal direction,
It differs from the heat exchanger having the structure shown in the above embodiment only in the cross-sectional shapes of the headers (5) and (6) and the presence or absence of a partition member. Condenser header according to this embodiment (5)
(6) is because an internal pressure higher than that of the evaporator is added,
It has a circular cross section. As shown in FIG. 23, the headers (5) and (6) are provided with partition members (20) and (20) for partitioning the inside of the headers (5) and (6) in the longitudinal direction. . As a result, the heat exchange medium circulates in a meandering manner in the heat exchanger.

Since the other construction is exactly the same as that of the first embodiment, the corresponding portions are designated by the same reference numerals and the description thereof will be omitted.

[0062]

As described above, each flat tube of the heat exchanger according to the present invention is bent in the tube width direction at an appropriate position in the longitudinal direction, and the bent portions are straight tubular portions on both sides thereof. And a twisted bent portion provided with a twist of a predetermined angle.

With this structure, when the twisted bent portion of the flat tube is processed, a plurality of straight tubular flat tubes are arranged in parallel at predetermined intervals in the thickness direction, and a pair of headers are provided at both ends thereof. All tubes are bent simultaneously in the tube width direction at appropriate portions in the longitudinal direction of the tubes in a state in which they are arranged and the tube ends are connected to the header, and straight tubular portions on both sides of the bent portion of each tube It suffices to apply a twist bending process for imparting a twist of a predetermined angle to. Therefore, the processing of the twisted and bent portion of the tube is technically very easy to carry out, and thus a bent heat exchanger of this kind can be easily manufactured.

Further, during such twist-bending of the tube, there is a problem that the twist-bent portion of the tube is crushed and the internal passage cross-sectional area is narrowed to increase the internal pressure loss. It can be avoided.

Further, tube insertion holes corresponding to each tube are provided in a row, and an intermediate strip plate-shaped portion in which a boundary portion between the straight tubular portion and the twisted bent portion of each tube is inserted into the insertion hole, and the intermediate portion. A strip plate-shaped reinforcing plate that is bent and extends from both ends of the strip plate portion, and has outer strip plate portions that are integrally joined to fins arranged outside the outermost tube in a juxtaposed arrangement state. When the tube is bent, the straight tubular portion is less likely to be twisted or bent, so that the tube can be surely bent with a small radius of curvature. .

When the twisted bent portions of adjacent tubes are brought into contact with each other in a state of being overlapped with each other, the strength on the bent portion side can be improved.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a heat exchanger (evaporator) according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a front view of the above heat exchanger.

FIG. 4 is a plan view of the above heat exchanger.

FIG. 5 is a bottom view of the above heat exchanger.

FIG. 6 is an enlarged front view of the twisted and bent portion of the tube of the heat exchanger of the above.

FIG. 7 is a partially enlarged perspective view of a strip plate reinforcing plate.

8 (a) to (c) are explanatory views showing the manufacturing process of the heat exchanger in the same as above.

FIG. 9 is an explanatory view showing bending of the heat exchanger of the above.

FIG. 10 is a perspective view showing a part of a flat tube of the above heat exchanger.

FIG. 11 is a cross-sectional view showing a modified example of the header.

FIG. 12 is a cross-sectional view according to a modified example showing a state in which the baffle member is loaded in the header.

FIG. 13 is a partially enlarged perspective view of a strip plate reinforcing plate according to a modification.

FIG. 14 is a plan view of a heat exchanger according to a modified example.

FIG. 15 is a graph showing the relationship between the amount of heat exchanged and the outlet pressure.

FIG. 16 is a graph showing the relationship between heat exchange medium side pressure loss and the same medium flow rate.

17 to 21 show a heat exchanger (evaporator) according to a second embodiment of the present invention.
FIG. 3 is a front view of the heat exchanger.

18 is a sectional view taken along line XVIII-XVIII in FIG.

FIG. 19 is a perspective view of a tube that has been twist-formed.

FIG. 20 is a front view showing a state before bending and forming the heat exchanger.

FIG. 21 is a plan view showing a state after the heat exchanger is bent and formed.

22 and 23 show a heat exchanger (condenser) according to a third embodiment of the present invention, and FIG. 22 is an overall perspective view of the heat exchanger.

FIG. 23 is a left side view of the above heat exchanger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flat tube 2 Straight tubular part 3 Straight tubular part 4 Torsional bent part 5 Hollow header 6 Hollow header 11 Corrugated fin 12 Corrugated fin 13 Strip plate-shaped reinforcing plate 14 Strip plate-shaped reinforcing plate 15 Intermediate strip plate-shaped portion 15a Tube insertion hole 16 Outer strip plate

Claims (3)

[Claims] 1. A plurality of flat tubes arranged in parallel to each other at a predetermined interval in the thickness direction, and a pair of hollow headers arranged at both ends of the tubes and having tube ends communicating with each other. Each of the tubes is formed by bending in the tube width direction at an appropriate position in the longitudinal direction, and the bending portion has a twisted bending portion in which the straight tubular portions on both sides thereof are twisted at a predetermined angle. The heat exchanger characterized in that a fin is interposed between the adjacent straight tubular portions. 2. A plurality of flat tubes arranged in parallel with each other at a predetermined interval in the thickness direction, and a pair of hollow headers arranged at both ends of the tubes and having tube ends connected to communicate with each other. Each of the tubes is formed by bending in the tube width direction at an appropriate position in the longitudinal direction, and the bending portion has a twisted bending portion in which a twist of a predetermined angle is applied to the straight tubular portions on both sides thereof. Further, the fins arranged between the adjacent straight tubular portions and outside the outermost tube, and tube insertion holes corresponding to the tubes are arranged in a row,
An intermediate strip plate-shaped portion in which the boundary portion between the straight tubular portion and the twisted bent portion of each tube is inserted into the insertion hole, and bent and extended from both ends of the intermediate strip plate-shaped portion, respectively, the outermost portion A heat exchanger, comprising: a strip-shaped reinforcing plate having an outer strip-shaped portion integrally joined to a fin arranged outside the tube in a juxtaposed arrangement. 3. The heat exchanger according to claim 1, wherein the twisted bent portions of adjacent tubes are in contact with each other in an overlapping state.