JP2003227692A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger which inhibits mixing of both brazing materials in brazing by using two kinds of brazing materials. <P>SOLUTION: The heat exchanger comprises: a tube 110 including a first plate shaped member 111 and a second plate shaped member 112, including a fluid passage 110a formed inside, and laminated in a plurality of layers; and a fin 130 with a cross section in an uneven shape, and interposed between each of the tubes 110. An outer peripheral part or a part of the outer peripheral part of the tube 110 includes a fastening part 110d which is formed by fastening the first plate shaped member 111 by the second plate shaped member 112, and the fastening part 110d is joined by a first brazing material. The tube 110 and the fin 130 are joined by a second brazing material different from the first brazing material, and a terminal part 131 of the fin 130 in a direction of the uneven shape is joined to the second plate shaped member 112 of the tube 110. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat exchanger for exchanging heat between a fluid and a combustion gas, and is particularly suitable for use as a heat exchanger for a water heater.

[0002]

As a conventional technique, for example, Japanese Patent Laid-Open No. 9-1
There is a heat exchange device described in Japanese Patent No. 26554. This heat exchange device includes a main heat exchanger that recovers sensible heat of combustion gas to heat hot water, and a sub heat exchanger that is arranged downstream of the main heat exchanger in the flow direction of combustion gas. The sub heat exchanger also recovers the latent heat of condensation of the combustion gas to heat the hot water before being heated by the main heat exchanger.

[0003]

However, in the above sub heat exchanger, the temperature of the combustion gas is the dew point temperature (50 to 6).
Nitrogen oxide (NO) in combustion gas
x) and sulfide oxide (SOx) dissolved acidic condensed water is generated.

Therefore, when a so-called drone cup type heat exchanger capable of ensuring a large heat transfer area is used as the auxiliary heat exchanger, the joint between the fin and the tube directly exposed to the condensed water and the hot water supply flow. This causes the problem of corroded joints of the tubes.

That is, a tube used in a Delon cup type heat exchanger is usually formed by combining two heat transfer plates (tube plates) in the plate thickness direction and brazing the peripheral portions of both. ing. Furthermore, a plurality of these tubes are laminated, fins are interposed between the tubes, and the fins and the tubes are brazed. If a Cu-based brazing material is used for these joints, the generated condensate will cause brazing. This means that the materials will corrode and it will not be possible to secure sufficient joint strength (durability).

To solve this problem, for example, Japanese Patent Laid-Open No. 9-2
As described in Japanese Patent No. 85888, it is known that brazing may be performed with a Ni-based brazing material. However, according to WHO (World Health Organization) guidelines for drinking water quality, Cu is 0.5 mg / L, whereas Ni is 0.02 mg / L, which is severe, so there is a possibility of direct exposure to hot water. It is not desirable to use Ni-based brazing material at the joints of certain tubes.

Therefore, the present inventors have used a Ni-based brazing material for brazing between the fin and the tube which is directly exposed to the combustion gas (condensed water), and the joint portion of the tube which is directly exposed to the hot water. It was thought that both corrosion resistance and safety should be ensured by using a Cu-based brazing material. Furthermore, considering the compactness of the joints of the tubes, we considered the structure to be a winding structure to secure a long brazing length to improve the corrosion resistance. A new problem was discovered that the materials could be mixed.

The present invention has been made based on the above circumstances, and an object thereof is to provide a heat exchanger capable of suppressing the mixing of both brazing filler metals when brazing with two types of brazing filler metals. To provide.

[0009]

The present invention employs the following technical means in order to achieve the above object.

According to the first aspect of the invention, a tube which is composed of the first plate-shaped member (111) and the second plate-shaped member (112) and which has the fluid passage (110a) formed therein, and which is laminated in plurality. (110), the cross section is formed in an uneven shape,
Fins (130) interposed between the tubes (110)
And a fluid passageway (110a) of the tube (110).
In the heat exchanger for exchanging heat between the internal fluid flowing through the tube and the external fluid flowing through the fin (130), the outer peripheral portion of the tube (110) or a part of the outer peripheral portion of the first plate member (111 ) Forms a winding portion (110d) which is wound by the second plate member (112), and
The tightening portion (110d) is joined by a first brazing material, the tube (110) and the fins (130) are joined by a second brazing material different from the first brazing material,
The uneven end portion (131) of the fin (130) is
It is characterized in that it is adapted to be joined to the second plate-shaped member (112) of the tube (110).

As a result, while securing the heat dissipation area of the fin (130), the winding end portion (11) of the end portion (131) of the fin (130) in the uneven direction and the winding fastening portion (110d).
0e) can be made longer, and mixing of two different types of brazing filler metal during brazing can be suppressed.

Then, as in the invention described in claim 2,
At the time of brazing, the inner fluid as the heat exchanger is the hot water, the outer fluid is the combustion gas, the first brazing material is the Cu-based brazing material, and the second brazing material is the Ni-based brazing material. It is possible to suppress the mixing of the two types of brazing filler metal in (1) and (2) above to obtain a heat exchanger having excellent corrosion resistance against combustion gas and safety against hot water.

The reference numerals in parentheses of the above means indicate the corresponding relationship with the concrete means described in the embodiments described later.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of the present invention will be described with reference to the drawings shown in FIGS. The heat exchanger 100 of the present invention is used in a water heater to perform heat exchange between hot water as an internal fluid and combustion gas as an external fluid. As shown in FIGS. The tubes 110 are stacked, and the fins 130 are interposed between the tubes 110 to form a heat exchanger 100 of a so-called drone cup type. It should be noted that all the members (described below) constituting the heat exchanger 100 are made of stainless steel materials here, and are manufactured by integral brazing after the entire shape is assembled.

As the tube 110, a tube plate (first plate member) 111 shown in FIG. 4 and a tube plate (second plate member) 112 shown in FIG. It is formed by And as a whole shape, a flat tube portion 110b forming a U-shaped flowing water passage (fluid passage) 110a therein and a pair of tank portions 110c communicating with both ends of the flowing water passage are provided.
A communication port 111a is opened at 10c.

Flange portions 111b are provided on the outer peripheral portions of the tube plates 111 and 112, and a punching portion 111c for forming the flowing water passage 110a in a U-shape is provided inside. Further, the tube plate 112 has a flange portion 11 on the outer peripheral portion with respect to the tube plate 111.
A claw portion 112a is provided over the entire circumference of 1b.

In forming the tube 110, the tube 111 and 112 are provided with a winding structure so that the tubes 111 and 112 are compact and the length of the joint portion 113 is long in order to improve corrosion resistance.

That is, as shown in FIG. 1, after the two tube plates 111 and 112 are combined, the tube plate 1 is attached to the flange portion 111b of the tube plate 111.
The claw portions 112a of 12 are tightened by winding to form a tightening portion 110d, and the length of the joint portion 113 is earned.
The joint 113 is joined by a Cu-based brazing material (first brazing material) in consideration of safety against hot water.

Both tube plates 1 abutting each other
Similarly, the embossed portions 111c of 11, 112 are also joined by a Cu-based brazing material.

The tank portion 110c is provided with a thickness width larger than that of the flat tube portion 110b, and the outer surfaces of the tube plates 111 and 112 forming the tank portion 110c are
A flat portion 111d is annularly provided around the communication port 111a.

As shown in FIG. 3, the plurality of tubes 110 are formed by stacking the tank portions 110c of each other in series and joining the flat portions 111d provided around the communication port 111a. As a result, the running water passage 1 of each tube 110 is passed through the communication port 111a opening to the tank portion 110c.
10a communicate with each other. Inner fins may be inserted inside the tube 110 to increase the heat transfer area.

The fins 130 are formed by bending a thin plate material into an uneven shape, and are arranged so that the combustion gas flows from the upper side to the lower side in the uneven space, and the tube plates 111, 112 forming the flat tube portion 110b. On the surface of Ni
They are joined by using a system brazing material (second brazing material). The Ni-based brazing material is selected in consideration of improving the corrosion resistance against the condensed water of the combustion gas.

The tube plate 111 of the fin 130,
When brazing to 112, the feature of the present invention is that the end portions 131 of the fins 130 in the concave-convex direction are arranged in the direction shown in FIG.
As shown in FIG. 3, the tube plate 112 is joined.

As shown in FIG. 2, a hot water supply port 140 and a hot water supply port 150 are joined to the tank portion 110c of the tube 110 arranged on one end side in the stacking direction.
Reinforcing plates 160 are joined to both ends in the stacking direction.

Next, a method for manufacturing the heat exchanger 100 will be briefly described. First, the tube plate 111 and the tube plate 112 are aligned in the middle, and the claw portion 112a is formed.
The tube 110 is assembled by winding and tightening. At this time, a Cu-based brazing material (brazing sheet) is interposed in the joining portion 113 of the winding tightening portion 110d. When the inner fin is inserted into the tube 110, a Cu-based brazing material (brazing sheet) is interposed between the inner fin and the tube plates 111 and 112. (Tube assembly).

Next, the flat tube portion 110b of the tube 110.
Ni-based brazing material is applied to the surface of the
A Cu-based brazing material is applied to the surface of the flat portion 111d of c. (Applying brazing material).

Next, the tubes 110 and the fins 130 are alternately laminated on the reinforcing plate 160, and another reinforcing plate 160 is set on the uppermost tube 110. Then, the stacked tubes 110, fins 130 and reinforcing plates are fixed by a predetermined jig or the like, and the hot water inlet 140 and the hot water outlet 150 are temporarily fixed to the tube 110 on one end side by caulking or the like to assemble the heat exchanger. The body. (Heat exchanger assembly).

Finally, the above assembly is put into a furnace and each member is brazed together. (Integral brazing).

In this heat exchanger 100, hot water is supplied from the hot water supply port 140 to one tank portion 1 of each tube 110.
10c, flows from one of the tank portions 110c through the flowing water passage 110a formed in the flat tube portion 110b, flows into the other tank portion 110c, and the other tank portion 1c.
It flows out from 10c through the tap hole 150.

On the other hand, as shown in FIG. 2, the combustion gas flows from the upper side to the lower side of the heat exchanger 100, and when passing through the heat exchanger 100, heat is exchanged with the hot water to heat the hot water. . At this time, the combustion gas contains at least the heat exchanger 10.
On the outlet side of 0, the temperature is lowered to a temperature below the dew point temperature (for example, 30 to 50 ° C.), and condensation is performed. That is, this heat exchanger 100 is
Not only the sensible heat of the combustion gas but also the latent heat released when the combustion gas is condensed can be absorbed to heat the hot water.

In the present invention, two types are used from the viewpoints of improving the corrosion resistance to condensed water produced by condensing combustion gas (acidic condensed water described in the section of the above-mentioned prior art) and improving safety against hot water. A brazing material (Cu-based and Ni-based) is used, but the terminal end portion 13 of the fin 130 in the uneven shape direction is used.
Since 1 is regulated and joined to the tube plate 112 side, the winding of the winding tightening portion 110d is greater than when the terminal end portion 131 of the fin 130 is joined to the tube plate 111 side (two-dot chain line in FIG. 1). The distance from the tightened end 110e can be increased (X> Y), and the heat dissipation area of the fins 130 can be secured, while mixing of two different types of brazing filler metal can be suppressed during integral brazing. That is, it is possible to ensure safety on the hot water supply side.

(Other Embodiments) In the first embodiment, the heat exchanger 100 is applied to a water heater and the fluids that exchange heat with each other are hot water and combustion gas. However, the present invention is not limited to this. It is also possible to target the above fluid.

Also, the winding tightening portion 110d of the tube 110
Although it has been described that it is provided on the outer peripheral portion, it may be provided on a part thereof.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment. (It is sectional drawing of the AA part in FIG. 2.)

FIG. 2 is a front view showing a heat exchanger according to the first embodiment.

3 is a view from the direction B in FIG.

4A is a top view, FIG. 4B is a front view, and FIG. 4C is a bottom view of the first tube plate.

5A is a top view, FIG. 5B is a front view, and FIG. 5C is a bottom view showing a second tube plate.

[Explanation of symbols]

100 heat exchanger 110 tubes 110a running water passage (fluid passage) 110d winding part 111 tube plate (first plate member) 112 Tube plate (second plate member) 130 fins 131 Terminal

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B23K 101: 14 B23K 101: 14 F term (reference) 3L036 AA01 AA42 AE03 3L103 AA01 AA12 AA27 AA43 BB43 CC06 CC27 DD13 DD32 DD34

Claims (2)

[Claims] 1. A fluid passageway (110) comprising a first plate-shaped member (111) and a second plate-shaped member (112).
a), a plurality of stacked tubes (110) and fins (130) having an uneven cross section and interposed between the tubes (110) are provided. A heat exchanger for exchanging heat between an internal fluid flowing through a fluid passage (110a) and an external fluid flowing through the fin (130), wherein an outer peripheral portion of the tube (110) or a part of the outer peripheral portion is A winding tightening portion (110) in which the first plate-shaped member (111) is wound around the second plate-shaped member (112).
d) is formed, the tightening portion (110d) is
Joined by a first brazing material, the tube (110) and the fin (130)
Are joined by a second brazing material different from the first brazing material, and the fin-shaped end portion (13) of the fin (130) in the concave-convex direction is joined.
1) is a heat exchanger characterized by being joined to the second plate-shaped member (112) of the tube (110). 2. The internal fluid is hot water, the external fluid is combustion gas, the first brazing filler metal is a Cu-based brazing filler metal, and the second brazing filler metal is Ni. The heat exchanger according to claim 1, wherein the heat exchanger is a brazing filler metal.