JPH09138093A - Drawn cup type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drawn cup type heat exchanger having a superior anti- corrosion characteristic in which a peeling-off corrosion characteristic at a connecting part of a tank segment is restricted and a cathode anti-corrosion effect is attained also at a plate segment. SOLUTION: This heat exchanger is constructed such that a large number of tube elements 1 having tank segments formed at both ends by overlapping two core plates 7, 7 and having a plate part with a coolant passage at an intermediate part and some fins 2 are piled up alternatively and brazed integrally to each other. Then, the core plates 7 are made of brazing aluminm material formed with brazing layers 9a, 9b at both surfaces of a core member 8. An outside brazing material layer 9a positioned at an outer surface of the tube element 1 is made of material which is less pin hole potential than that of the core member 8, and further a pin hole potential at a connecting part of each of the tank segments of the adjoining tube element 1 is set to be more noble than that of the outside brazing material 9a.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a drone cup type heat exchanger having excellent corrosion resistance.

[0002]

2. Description of the Related Art For example, a laminated type heat exchanger called a "Drone cup type" is often used as an aluminum heat exchanger used as an air conditioner evaporator for an automobile, an industrial radiator, or an oil cooler. .

This drone cup type heat exchanger is made of a brazing sheet, which is press-formed into a dish shape so as to form a heat exchange medium flowing portion and a tank portion communicating therewith.
A tube element is formed by laminating a plurality of core plates to form a tube element, and the fins and the fin are alternately laminated in a plurality of stages to be integrated by brazing.

Such a drone cup type heat exchanger may be constructed to have corrosion resistance in order to withstand use in a corrosive environment. However, the conventional anticorrosion concept is as follows. The core material of the core plate is made of an Al alloy corresponding to JIS A3003, and the core material of the fin is made of an alloy equivalent to JIS A3203 having a low pitting potential, Zn, I
The fins are made of an Al alloy to which an element having a sacrificial corrosion effect such as n and Sn is added, and the fins are used for cathodic protection of the tube element (for example, JP-A-63-24).
1137).

[0005]

However, in an environment where the entire heat exchanger gets wet, corrosion resistance is secured by the sacrificial corrosion effect of the fins, but in an environment where the heat exchanger is partially wet, the tube elements are brazed to each other. There is a problem that the part, that is, the joint part of the tank part, rather promotes the progress of peeling corrosion.

The present invention has been made in view of the above technical background, and it is a drone cup type which is excellent in corrosion resistance and which suppresses peeling corrosion at a joint portion of a tank portion and has a cathodic protection effect even at a plate portion. The purpose is to provide a heat exchanger.

[0007]

In order to achieve the above-mentioned object, the Delon cup type heat exchanger according to the present invention has two dish-shaped core plates (7) and (7) superposed on each other so as to face each other. Allows the tank parts (3a) (3b) to be bulged at both ends in the length direction.
And a flat tube element (1) in which a plate portion (5) having a refrigerant passage (4) communicating with the tank portions (3a) and (3b) is formed in the middle portion, and a fin (2) And a large number of layers are alternately laminated, the plate portion (5) of the tube element (1) and the fins (2) are brazed, and the tank portions (3a) (3) of the adjacent tube elements (1) (3)
(a), (3b) and (3b) are connected to each other by brazing so as to be integrated with each other.
(7) is made of a brazing aluminum material in which brazing material layers (9a) and (9b) are formed on both surfaces of the core material (8), and the outer brazing material layer (9a) located on the outer surface of the tube element (1) is The tank parts (3a) (3a), (3) of the tube element (1), which are formed of a material having a pitting potential lower than that of the core material (8) and are adjacent to each other,
b) (3b) The pitting corrosion potential of the mutual joint is the outer brazing filler metal layer (9
Basically, it is set to you rather than a).

In the Delon cup type heat exchanger of the present invention,
Regarding the pitting potential, the brazing filler metal layer (9a) outside the core material (8) of the core plate (7) constituting the tube element (1) is made base and the core material (8) is cathodically protected by the surface layer, while adjacent Tank parts (3a) (3a), (3b) (3) of tube element (1)
b) A core material that makes the joints more precious than the outer brazing material layer (9a)
By reducing or eliminating the potential difference between (8) and the surface layer (junction), the cathodic protection effect of the core material (8) by the surface layer is suppressed. That is, the pitting potential of the surface layer of one tube element (1) is determined by the fin (2) and the plate portion (5) to be brazed.
In order to improve the corrosion resistance of the entire heat exchanger, it is made less base than the core material (8), and the adjacent tube elements (1) and the brazed tank parts (3a, 3b) are made to approximate the core material (8). ing. The pitting corrosion potential of the joint may be noble or base with respect to the core material (8) of the core plate (7), but in order to significantly improve the corrosion resistance, the pitting corrosion potential should be the same or slightly base. Preferably there is.

The preferred pitting potential difference for improving the corrosion resistance is 150 mV or more, particularly preferably 200 mV or more between the core material (8) and the outer brazing material layer (9a), and the outer brazing material layer
(9a) and the insert material (13) are 80 mV or more, particularly preferably 150 mV or more, and the core material (8) and the joint part are 200 mV or more.
Less, particularly preferably less than 150 mV.

The structure of each part of the heat exchanger is not limited as long as the pitting potential difference as described above can be generated. In particular, the tank parts (3a) (3
a), (3b) (3b) as means for setting the pitting corrosion potential of the mutual joint to be nobler than the outer brazing filler metal layer (9a), the tank portion to be joined (3a) (3a), (3b), (3b), an insert material (13) having a pitting corrosion potential higher than that of the outer brazing material layer (9a) is interposed, and the insert material (13) and the outer brazing material layer ( 9a) and the method of fusing can be recommended.

Further, the constituent material of each part of the heat exchanger is not limited as long as the pitting potential difference as described above can be generated. In particular, as a material capable of setting a predetermined pitting potential difference, various materials having the following compositions can be exemplified.

First, in the brazing aluminum material constituting the core plate (7), the core material (8) is Mn;
5 to 2.0 wt% and Cu; 0.1 to 1.0 wt%, the balance consisting of Al and impurities, Fe as impurities is 1.0 wt% or less, Si is 1.0 wt% or less, and Mg is 1.0 wt% or less, Cr 0.5 wt% or less, Zn 0.5
It is preferable that the aluminum alloy is made of an Al alloy whose wt% or less and Ti is 0.2 wt% or less. Here, Mn is an element effective in making the potential noble and easily providing a difference in pitting potential between the core material (8) and the outer brazing filler metal layer (9a) and improving the strength. If it is less than the above range, the effect of addition is poor, and if it exceeds the upper limit, the intermetallic compound becomes large and work hardening becomes remarkable, resulting in deterioration of formability. A particularly preferable lower limit of the Mn content is 0.7 wt%, a more preferable lower limit thereof is 0.8 wt%, a particularly preferable upper limit thereof is 1.8 wt%, and a further preferable upper limit thereof is 1.5 wt%. Also, Cu is an element effective for making the potential noble, and if it is less than the lower limit value, the addition effect is poor, and if it exceeds the upper limit value, it diffuses to the surface through the brazing filler metal grain boundaries and the corrosion resistance is poor. Become. A particularly preferred lower limit of the Cu content is 0.
2 wt%, a more preferable lower limit is 0.3 wt%, a particularly preferable upper limit is 0.9 wt%, and a more preferable upper limit is 0.7 wt%. Further, Fe and S as impurities
When the content of each of i, Mg, Cr, Zn, and Ti is high, the corrosion resistance or formability may decrease, but there is no problem if the content is below the upper limit. Particularly preferable regulation values for each of these elements are 0.8 wt% or less for Fe and 0.
6 wt% or less, Mg 0.5 wt% or less, Cr 0.3 wt%
Hereinafter, Zn is 0.3 wt% or less and Ti is 0.1 wt% or less.

The outer brazing material layer (9a) of the aluminum material for brazing achieves good brazing and
To make the pitting potential less base than the core material (8), A
An alloy based on an 1-Si alloy to which an element having a base pitting potential is added, that is, containing Si: 6 to 14 wt% and further Z
n: 0.6 to 2.5 wt%, In: 0.02 to 0.1 wt%
%, Sn; at least one of 0.02-0.1 wt%
An Al alloy containing a seed and the balance consisting of Al and impurities can be recommended. Of the additional elements, Si is preferably added in an amount within the above range in order to secure an appropriate melting point as a brazing material. A particularly preferred lower limit of Si content is 7 wt%, a more preferred lower limit is 8 wt%, a particularly preferred upper limit is 12 wt%, and a more preferred upper limit is 11%.
wt%. Here, Zn, In, and Sn have the effect of making the pitting potential base. From the viewpoint of this effect, these are equivalents, and it is sufficient that at least one kind is contained, and particularly Zn is used in flux brazing and I is used in vacuum brazing.
n or Sn may be used. However, if Zn is less than 0.6 wt%, In is less than 0.02 wt% and Sn is less than 0.02 wt%, the above effect is poor. On the other hand, if Zn exceeds 2.5 wt%, In exceeds 0.1 wt%, and Sn exceeds 0.1 wt%, not only the effect is saturated, but also in the case of In and Sn, the workability deteriorates. A particularly preferred lower limit of the Zn content is 0.9 wt%, a more preferred lower limit is 1.2 wt%, a particularly preferred upper limit is 2.2 wt%, and a more preferred upper limit is 1.8 wt%. Particularly preferable lower limits of In content and Sn content are 0.03 wt%, respectively, and particularly preferable upper limits thereof are 0.07 wt%, and further preferable upper limits thereof are 0.06 wt%, respectively.

The outer brazing material layer (9a) is made of an Al alloy in which Mg is further added to the above-mentioned additional elements Si, Zn, In and Sn, that is, Si; 6 to 14 wt% and Mg;
5 to 2 wt% Zn, 0.6 to 2.5 wt%
%, In; 0.02-0.1 wt%, Sn; 0.02-
It contains at least one of 0.1 wt% and the balance is A
It is also preferable to use an Al alloy composed of 1 and impurities. Mg has a getter action in a vacuum, and particularly has an effect of improving brazing property in vacuum brazing. Mg
If the content is less than 0.5 wt%, the above effect is poor, and 2.
The effect is saturated even if it exceeds 0 wt%. A particularly preferred lower limit of the Mg content is 0.8 wt%, a more preferred lower limit thereof is 1.0 wt%, and a particularly preferred upper limit thereof is 1.7 wt%,
A more preferable upper limit value is 1.5 wt%.

The inner brazing material layer (9b) of the brazing aluminum material is used for forming one tube element (1) by joining two core plates (7) and (7) together. After attachment, it will be the inside of the heat exchanger. Therefore, the environment of use is not much affected by corrosion, and the outer brazing material layer (9
Nobleness of pitting potential is not a problem as in a). Therefore,
The composition of the inner brazing material layer (9b) is not particularly limited, but Al: Si containing 6 to 14 wt% of Si in view of the brazing temperature.
System alloys are preferred.

In the brazing aluminum material,
The most common method of forming the brazing filler metal layers (9a) and (9b) on both surfaces of the core material (8) is a method of clad by rolling. The brazing material layers (9a) and (9b) have a clad ratio of 8 on one side.
It is better to set it to ~ 20%. If it is less than 8%, the brazing fillet may be insufficient and the brazing property may be inferior. If the cladding ratio exceeds 20%, Si erosion may increase.
There is a thermal spraying method as another method for forming the brazing material layers (9a) and (9b).

The insert material (13) has a pitting potential which is nobler than the outer brazing material layer (9a) of the brazing aluminum material, and the outer brazing material layer (9a) is heated by heating during brazing.
And the pitting corrosion potential of the core material (8) are approximated to suppress the cathodic protection effect of the outer brazing filler metal layer (9a) on the core material (8). Therefore, the composition of the insert material (13) is relatively determined by the composition of the outer brazing material layer (9a). For example, an Al alloy based on an Al-Si alloy in relation to the brazing temperature and containing an element effective for noble potential, Si: 6 to 14 wt% is contained, Mn: 2.0 wt% or less, An Al alloy brazing material containing at least one of Cu; 1.0 wt% or less, Ti: 0.2 wt% or less, Fe: 1.0 wt% or less, and the balance being Al and impurities can be exemplified. Mn, Cu, Ti, F
Each of e is an element that makes the pitting potential noble, and if each exceeds the upper limit, the melting point of the insert material (13) becomes high and the brazing property is hindered. A particularly preferred lower limit of the Mn content is 0.1 wt%, a more preferred lower limit is 0.2 wt%, a particularly preferred upper limit is 1.0 wt%, and a more preferred upper limit is 0.8 wt%. A particularly preferable lower limit of the Cu content is 0.2 wt%, and a further preferable lower limit thereof is 0.3 wt%.
%, A particularly preferable upper limit value is 0.9 wt%, and a further preferable upper limit value is 0.7 wt%. A particularly preferred lower limit of the Ti content is 0.001 wt%, a more preferred lower limit thereof is 0.003 wt%, and a particularly preferred upper limit thereof is 0.1
wt%, and a more preferable upper limit value is 0.07 wt%. F
A particularly preferred lower limit of the e content is 0.05 wt%, a more preferred lower limit is 0.1 wt%, a particularly preferred upper limit is 0.8 wt%, and a more preferred upper limit is 0.6 wt%.

Further, as the outer brazing material layer (9a), Zn, In, S having a base potential on the Al-Si alloy base is used.
When an Al alloy added with one or more of n is used, Zn in the Al alloy is used as the insert material (13),
Even if an Al alloy containing a small amount of added In and Sn is used, the potential can be made relatively nobler than that of the outer brazing material layer (13). Zn: less than 0.6 wt%, In: less than 0.02 wt%, Sn: less than 0.02 wt% is preferable to ensure a significant potential difference between the insert material (13) and the outer brazing material layer (9a). . However, in the composition of the insert material (13),
When the element added for the purpose other than adjusting the potential makes the potential noble as a result, even if the content of Zn, In and Sn exceeds the above range, it is significant for the outer brazing filler metal layer (9a). A potential difference can be generated.

As shown in FIG. 1, the insert material (13) may be composed of only an Al alloy brazing material having the above-mentioned composition, and as shown in FIG. A laminated body in which the Al alloy brazing filler metal layers (21) and (21) having the above composition are formed may be used. In the latter case, the material of the core material (20) is not particularly limited, but an Al alloy having the same composition as or close to that of the core material (8) of the core plate (7), 1000 series pure Al, 3000
A system Al alloy etc. are preferable.

The appropriate thickness of the insert material (13) depends on the composition of the core material (8) of the core plate (7), the composition and thickness of the outer brazing material layer (9a), and the composition of the insert material (13). It is determined. This is because the insert material (13) is used to form a layer having a pitting potential close to that of the core material (8) by fusing with the outer brazing material layer (9a). However, the insert material (1
If the thickness of 3) is too thick, Si erosion of the core material (8) of the core plate (7) tends to increase, so the thickness of the insert material (13) is 0.06 to 0.12 mm or the outer brazing material layer (9a). 100-200% of the thickness of () is preferable.

In the Delon cup type heat exchanger of the present invention,
Core plates (7) that make up the tube element (1)
Is an aluminum material for brazing in which a brazing filler metal layer (9a) having a pitting potential lower than that of the core material (8) is formed on the outside of the core material (8), and the tank portion of the adjacent tube element (1) is used. (3a) (3a), (3b) (3b) Since the pitting corrosion potential of the mutual joint is set to be nobler than that of the outer brazing filler metal layer (9a),
In the plate part (5) where (2) is joined, the core plate
The core material (8) of (7) is covered with a surface layer having a lower pitting potential, and the tank portions (3a) and (3b) are covered with a surface layer whose pitting potential is similar to that of the core material (8). Therefore, the core material (8) is
While the outer brazing filler metal layer (9a) of (5) protects against corrosion, the joints of the tank parts (3a) and (3b) suppress the anticorrosion effect, and the tank parts (3a) (3a), (3b) ) The occurrence of exfoliation corrosion at the joint interface of (3b) is prevented.

During brazing, the pitting corrosion potential is higher than that of the outer brazing filler metal layer (9a) between the tank portions (3a) (3a), (3b) and (3b) of the adjacent tube elements (1). Noble insert material
When the (13) is interposed, a layer in which the outer brazing filler metal layer (9a) and the insert material (13) are fused is formed in the joint portion of the tank portions (3a) and (3b), and the pitting corrosion potential is It becomes more noble than the outer brazing filler metal layer (9a) and has a pitting potential similar to that of the core material (8).

[0023]

1 to 6 show an example of a drone cup type heat exchanger according to the present invention, which is applied to an aluminum alloy evaporator for an air conditioner of an automobile.

In the overall view of the evaporator shown in FIG. 6, (1)
Is a plurality of flat tube elements that are vertically stacked in the left-right direction, (2) is between the adjacent tube elements (1) and (1) and the outermost tube element (1)
It is a corrugated fin that is arranged on the outer side of and is integrated with brazing.

Each of the tube elements (1) is shown in FIGS.
As shown in FIG. 6, bulging tank parts are provided at both ends in the length direction.
(3a) and (3b), and a plate portion (5) that constitutes a flat refrigerant passage (4) that connects both tank portions (3a) and (3b) to the middle portion in the longitudinal direction. . The tube elements (1) are adjacent to each other and the tank parts (3a) (3b)
At the same time, they are brazed and joined to each other, and the adjacent tank portions are in communication with each other via the refrigerant circulation holes (6) and (6) provided in the tank portions (3a) and (3b).

In each of the tube elements (1), two dish-shaped core plates (7) are attached to their peripheral end joint surfaces (7a).
In the above, they are formed in such a manner that they are overlapped with each other in an opposed manner and integrated by brazing. The core plate (7) is formed by pressing, and the core material (8) is used for the purpose of easily joining the core plates (7) to each other and brazing the corrugated fins (2) together. On both sides of the brazing material layer (9
A brazing sheet in which a) and (9b) are clad by rolling is used.

As shown in FIG. 5, the core plate (7)
Except for the outer core plate (7 ') that constitutes the outermost tube element (1), outwardly projecting cup portions (10) are formed at both ends, and the core plate (10) is formed on the top wall thereof. Three refrigerant flow holes (6) are formed along the width direction of (7). As shown in FIG. 5, the outer core plate (7 ') of the outermost tube element (1) is flat at both ends, and has three refrigerant flow holes (6) along the width direction at the lower end. ) Has been drilled.

[0028] And, such two core plates
By stacking (7) (7) or (7) (7 ') in an opposed manner, the tank portions (3a) (3b) are formed in the cup portion (10), and the refrigerant flow holes (6) are formed. Tank parts (3a) (3a) or (3b) (3b) of tube elements (1) that are adjacent to each other through
They are in communication with each other. However, in the overall view of the evaporator shown in Fig. 6, the lower tank part (3) of the tube elements (1) (1) located at the fourth and fifth positions from the right
b) Mutual joint surface of (3b) and upper tank part (3a) (3a) of tube element (1) (1) located at the same 8th and 9th position
Of the cup portion (10) constituting the mutual joint surface of the tube element (1) (1) and the mutual joint surface of the lower tank portion (3b) (3b) of the tube element (1) located at the 13th position, respectively. In the top wall, the above-mentioned refrigerant flow holes are not bored,
Tank section of tube element (1) with its top wall adjacent
(3a) or (3b) act as partitions to each other, whereby a refrigerant passage constituted by all tube elements is formed in a meandering passage.

On the other hand, on the inner surface of each core plate (7), there is a concave shape that extends straight from one cup portion (4) toward the other cup (4) and also functions as a groove for draining condensed water. Inward protruding ribs (11) are formed at predetermined intervals in the width direction of the core plate (7). Then, by overlapping the two core plates (7) and (7) having such ribs (11), the peripheral end joint surfaces (7a) are joined together, and the solid line and the dash-dotted line are shown in FIGS. 2 and 3. As shown by and
The ribs (11) and (11) of both core plates (7) and (7) are arranged alternately, and the tips of the ribs (11) are arranged so that the ribs (11) of the opposing core plates (7) are ) Flat part between each other (12)
A plurality of units that are joined in an alternating arrangement abutting against each other and extend straight from the lower tank part (3b) toward the upper tank part (3a) in the refrigerant passage (4) of the tube element (1). A refrigerant passage (4a) is formed.

As shown in FIG. 1, a plurality of the above-mentioned chive elements (1) are arranged with corrugated fins (2) interposed between them, and the adjacent ones are adjacent to each other. The portions (3a) and (3b) are brazed in contact with each other via the insert material (13). Here, the core plates (7) are joined to each other via the inner brazing material layer (9b) of the core plate (7), and the tube element (1) and the corrugated fins (2) are joined to each other. ) Through the outer brazing material layer (9a) of the brazing sheet. Further, the adjacent tube elements (1) (1) are joined to each other through the outer brazing material layer (9a) of the brazing sheet and the insert material (13), and after brazing, the outer brazing material layer (9a). And the insert material (13) are fused to form an integrated fillet. In addition, in the lower tank part (3b) of the right outermost tube element (1), the refrigerant inlet pipe (14)
However, in the lower tank portion (3b) of the left outermost tube element (1), the refrigerant outlet pipe (15) is provided in each of the refrigerant circulation holes.
Connected via (6). 5 and 6, (16) is a side plate disposed outside the outermost corrugated fin, and these side plates (16) are also formed by a brazing sheet, and the outermost corrugated fin (16) is formed. It was brazed to 2).

In the evaporator as described above, the refrigerant inlet pipe (14)
The refrigerant that has flowed in from the inside of the tube element (1) divided by the partition changes its direction and flows in a meandering manner, and flows out of the evaporator from the outlet pipe (15). During this time, heat is exchanged with the air flowing through the air flow gap including the corrugated fins (2) formed between the tube elements (1).

Thus, each core plate (7) constituting the tube element (1) has an outer brazing filler metal whose base material (8) has a pitting potential lower than that of the core material (8) so as to cover the outside of the core material (8). Layer (9
a) will exist. As a result of preferential corrosion of the outer brazing filler metal layer (9a), the core material (8) of the tube element (1) is protected from corrosion, and thus pitting corrosion of the tube element (1) is prevented. Further, in the joint portion of the tank portions (3a) (3a), (3b) (3b), the fusion layer formed by the outer brazing material layer (9a) and the insert material (13) is an outer brazing material layer. (9a)
Since the pitting corrosion potential is nobler than that, corrosion is prevented by the outer brazing material layer (9a), and peeling corrosion between the tank portions (3a) (3a), (3b) (3b) is also prevented.

[0033]

Next, an embodiment of the present invention will be described.

As shown in FIGS. 1 to 6, a plurality of core plates (7) and (7) having the same composition are laminated and a plurality of them are alternately laminated with corrugated fins (2). It was temporarily assembled in the Delon cup type heat exchanger.

The brazing aluminum material forming the core plate (7) includes a plurality of compositions shown in Table 1 as materials for the core material (8), the outer brazing material layer (9a) and the inner brazing material layer (9b). Various kinds of materials were prepared and clad by rolling on both surfaces of the core material (8) with the combinations shown in Table 2 to prepare a brazing sheet, which was press-formed into a required shape. The thickness of the brazing sheet core material (8) is 0.4 mm, and the brazing material layers (9a) (9b)
The clad rate of each was 12%. Also, insert material (1
As 3), an Al alloy brazing material having the composition shown in Table 1 was prepared.
Among these insert materials, a-1 has the same composition as the core-2 and has a thickness of 0.024 on both surfaces of a core material having a thickness of 0.152 mm.
mm is a laminate having a brazing filler metal layer formed thereon, and the others have a thickness of 0.
It is a single layer of 1 mm. As the corrugated fin (2), a JIS3203Al alloy to which 0.05 wt% of In was added was used, and the thickness was set to 0.12 mm. Also, heartwood
Table 1 shows the pitting corrosion potentials of (8), the brazing material layers (9a) (9b), and the insert material (13).

Next, the above heat exchanger assemblies were brazed. Brazing was carried out by heating each heat exchanger of Examples 2 and 4 in vacuum at 600 ° C. for 5 minutes, and for other heat exchangers, immersing in a suspension of fluoride flux and drying. After that, 600 ° C in an inert gas atmosphere
It was carried out by heating for 5 minutes.

Then, for each of the obtained heat exchangers, the pitting corrosion potential of the fusion layer of the outer brazing filler metal layer (9a) and the insert material (13) was measured, and the corrosion test of the entire heat exchanger was conducted. .

The corrosion test is carried out by immersion in a test solution, natural drying, dew condensation (30 minutes), wet (30 minutes) and drying (45 ° C. ×).
The pitting corrosion depth of the tube element (1) was measured when 100 cycles were repeated for 1 hour) and repeated for 2 hours. The test solution was an acidic solution of pH 5 (5% NaCl + 5 ppm H ₂ S
O ₄ + 5% CaCl ₂ · 2H ₂ O + kaolin + sea sand) and an alkaline solution of pH 9 (7.5% CaCl ₂ · 2H ₂ O)
+ 5% NaCl).

The results are also shown in Table 2.

[0040]

[Table 1]

[0041]

[Table 2]

As can be seen from the results in Table 2, it was confirmed that the product of the present invention had excellent corrosion resistance without peeling corrosion on the joint surface of the tank portion.

[0043]

As described above, according to the present invention, by stacking two dish-shaped core plates so as to face each other, bulging tank portions are formed at both ends in the longitudinal direction, and an intermediate portion is formed. A flat tube element in which a plate portion having a refrigerant passage communicating with the tank portion is formed in a portion, and a large number of fins are alternately laminated, and the plate portion of the tube element and the fin are brazed together, In a drone cup type heat exchanger in which tank parts of adjacent tube elements are integrally brazed in a mutually communicating state, the core plate is made of a brazing aluminum material in which a brazing material layer is formed on both surfaces of a core material, The outer brazing filler metal layer located on the outer surface of the tube element is formed of a material having a pitting potential lower than that of the core material, and adjacent to the tube element. Since the pitting corrosion potential at the joint between the tank parts is set to be nobler than that of the outer brazing filler metal layer, the core material is protected by the outer brazing filler metal layer of the plate portion and at the joint portion of the tank part. Since the effect is suppressed, peeling corrosion at the joint interface can be prevented, the corrosion resistance of the tube element can be improved, and by extension, a drone cup heat exchanger having excellent corrosion resistance can be provided.

When an insert material having a higher pitting potential than the outer brazing material layer is interposed between the tank portions of the adjacent tube elements, the outer brazing material layer and the insert material are brazed to each other. By fusing, the pitting corrosion potential of the joint portion between the tank portions can be set to be nobler than that of the outer brazing material layer.

Further, the difference in the pitting potential required for improving the corrosion resistance is M as the core material of the aluminum material for brazing.
n: 0.5 to 2 wt% and Cu: 0.1 to 1 wt%, the balance consisting of Al and impurities, Fe as an impurity is 1 wt% or less, Si is 1 wt% or less, Mg is 1 wt% or less, Cr less than 0.5 wt%, Zn less than 0.5 wt%, T
An Al alloy in which i is regulated to 0.2 wt% or less is used, Si: 6 to 14 wt% is contained as an outer brazing material layer, and Zn: 0.6 to 2.5 wt%, In: 0.02 ~ 0.1
wt%, Sn; 0.02 to 0.1 wt%, at least one of which is Al alloy brazing material consisting of Al and impurities, or Si; 6 to 14 wt% and Mg;
5 to 2.0 wt%, and Zn; 0.6 to 2.5
wt%, In; 0.02-0.1 wt%, Sn; 0.02-
It contains at least one of 0.1 wt% and the balance is A
1 and an Al alloy brazing material consisting of impurities are used, the insert material contains Si; 6 to 14 wt%, Mn; 2.0 wt% or less, Cu; 1.0 wt% or less, T
It can be easily realized by using an Al alloy brazing material containing at least one of i: 0.2 wt% or less and Fe: 1.0 wt% or less, and the balance of Al and impurities. Furthermore, when using the Al-Si alloy brazing material added with at least one of Zn, In, and Sn described above or further added with Mg as the outer brazing material layer, as the insert material, , S
i: 6 to 14 wt%, and at least one of Zn, In, and Sn is contained in a smaller amount than the Al alloy constituting the outer brazing material layer, and the balance is Al and impurities. It can be easily realized by using an Al alloy brazing material.

[Brief description of the drawings]

1 is an enlarged cross-sectional view showing the vicinity of a tank portion of a tube element, showing a Delon cup type heat exchanger according to an embodiment of the present invention.

FIG. 2 is a plan view of a core plate forming a tube element as seen from a refrigerant passage side.

3A is a sectional view taken along line III-III in FIG. 2, and FIG. 3B is a partially enlarged view of FIG.

4A is a sectional view taken along line IVa-IVa in FIG. 2, and FIG. 4B is a sectional view taken along line IVb-IVb.

FIG. 5 is a perspective view showing a part of the Delon cup heat exchanger in a separated state.

FIG. 6 is an overall front view of a Delon cup heat exchanger.

FIG. 7 is an enlarged cross-sectional view of the vicinity of a tank portion of a tube element using another insert material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tube element 2 ... Fins 3a, 3b ... Tank part 4 ... Refrigerant passage 5 ... Plate part 7 ... Core plate 8 ... Core material 9a ... Outer brazing material layer 9b ... Inner brazing material layer 13 ... Insert material

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuhiro Kobori 224 Kaiyamacho, Sakai City Showa Aluminum Co., Ltd.

Claims (7)

[Claims] 1. Bulging tank portions (3a) (3b) are formed at both ends in the lengthwise direction by stacking two dish-shaped core plates (7) (7) facing each other. At the same time, a flat tube element (1) having a plate portion (5) having a refrigerant passage (4) communicating with the tank portions (3a) and (3b) in an intermediate portion
And a plurality of fins (2) are alternately laminated, and the plate portion (5) of the tube element (1) and the fins (2) are brazed, and adjacent tube elements (1)
In a drone cup type heat exchanger in which the tank parts (3a), (3a), (3b) and (3b) of the above are integrally brazed in a mutually connected state, the core plate (7) has both sides of the core material (8). Nisel layer (9a)
(9b) made of brazing aluminum material,
The outer brazing filler metal layer (9a) located on the outer surface of the tube element (1) is formed of a material having a lower pitting potential than the core material (8), and the tank portion (3a) of the adjacent tube element (1) is ) (3
A drone cup heat exchanger characterized in that the pitting corrosion potential at the joints of a), (3b) and (3b) is set to be nobler than that of the outer brazing filler metal layer (9a). 2. An insert material having a higher pitting potential than the outer brazing material layer (9a) between the tank portions (3a), (3a), (3b) and (3b) of adjacent tube elements (1). By interposing 13) and fusing with the outer brazing material layer (9a) by brazing, the pitting corrosion potential at the joint between the tank portions (3a), (3a), (3b) and (3b) is the outer brazing material. The drone cup heat exchanger according to claim 1, wherein the drone cup heat exchanger is set to be nobler than the material layer (9a). 3. A core material of the brazing aluminum material.
(8) is Mn; 0.5 to 2.0 wt% and Cu; 0.1
.About.1.0 wt%, with the balance being Al and impurities, Fe as impurities being 1.0 wt% or less, and Si being 1.
0 wt% or less, Mg 1.0 wt% or less, Cr 0.5 wt%
The Delon cup type heat exchanger according to claim 1 or 2, wherein Zn is regulated to 0.5 wt% or less and Ti is regulated to 0.2 wt% or less. 4. The outer brazing material layer (9a) of the brazing aluminum material contains Si; 6 to 14 wt%, and further Z
n: 0.6 to 2.5 wt%, In: 0.02 to 0.1 wt%
%, Sn; at least one of 0.02-0.1 wt%
The seed containing material, the balance consisting of Al and impurities.
The drone cup heat exchanger according to any one of 1 to 3. 5. The outer brazing material layer (9a) of the brazing aluminum material comprises Si; 6 to 14 wt% and Mg; 0.5.
~ 2.0 wt%, Zn; 0.6-2.5 wt%
%, In; 0.02-0.1 wt%, Sn; 0.02-
It contains at least one of 0.1 wt% and the balance is A
The drone cup type heat exchanger according to claim 1, which comprises l and impurities. 6. The insert material (13) is Si; 6-1
4 wt%, Mn; 2.0 wt% or less, Cu;
1.0 wt% or less, Ti; 0.2 wt% or less, Fe; 1.0
At least one of wt% or less is contained, and the balance is Al
The Delon cup type heat exchanger according to any one of claims 2 to 5, comprising: and impurities. 7. The insert material (13) is Si; 6-1
Al that constitutes 4% by weight and at least one of Zn, In and Sn constitutes the outer brazing material layer (9a).
The Delon cup type heat exchanger according to claim 4 or 5, wherein the content is smaller than the content of the alloy and the balance is Al and impurities.