KR19990086401A - Brazing method of tube-fin assembly of heat exchanger. - Google Patents

Abstract

The present invention relates to a brazing joining method of a tube-fin assembly of a heat exchanger, and includes a plurality of plate-shaped tubes (4) for fluid connection between fluid tanks, and zigzag-shaped thin plates disposed between and fixed to the tubes (4). The tube-fin of the tube-fin assembly of the heat exchanger having the bent chain fin 5 is formed as a bare material which is formed by extrusion molding or press molding, which is a material such as aluminum, and flux and silicon. (Slury) in which a mixture of (Si) is dissolved in a solvent and spray-coated with a spray gun to carry out brazing to weld a tube-pin; the flux and silicon (Si) are mixed in a 2: 1 weight ratio. ) And the slurry is mixed with alcohol or water in a 1: 1 weight ratio to form a slurry solvent;

The brazing joining method of the tube-pin assembly of the heat exchanger of the present invention is a useful invention that solves the problems of poor bonding, increased air handling, and cost improvement caused by processing as a conventional clad material.

Description

Brazing method of tube-fin assembly of heat exchanger.

The present invention relates to a brazing joint method of a tube-fin assembly of a heat exchanger, and more particularly, to the manufacture of a component having a (center) fin disposed between a plurality of tubes and tubes such as a car condenser, an evaporator, a radiator, and the like. It relates to the improvement of suitable brazing joining methods.

Automobiles, heat exchangers, air conditioners, etc. are provided with heat exchangers of various configurations such as condensers as heat exchange means,

The heat exchanger is different in size, shape, fluid flow configuration, etc., but the basic shape is a center that is a folding pin member for performing heat exchange with outside air by being fixed between a plurality of tubes and tubes connecting the fluid flow spaces at both ends. It is common to have a pin.

It is very cumbersome to make a fixed joint by forming a plurality of tubes and a pin connecting each tube, and it takes a lot of time and effort.

Conventionally, in the assembling structure of the tube-fin assembly of such a heat exchanger, in fixing the tube and the fin which is a thin zigzag-folded iron body which connects between tubes and arranges a plurality of louvers,

After the base material is coated on each member with a low melting point joining metal, the entire assembly is put into a brazing furnace so that the clad material coated on each member is welded and fixed to each other.

However, in the case of the above configuration, there is a cumbersome process process to ensure the fluidity of the clad metal at the time of brazing, and to apply a flux material which is a solvent for removing impurities on the surface of the tube and the fin.

Clad metals are expensive compared to conventional bare surface tubes and fins, and thus problems of manufacturing cost also exist.

In addition, it is not easy to set the optimum brazing temperature to fix the tube and the fin, and there is also a problem such as poor welding at the inner connection where no flux is applied in the assembly of the tube-pin.

1 is an exploded perspective view showing a condenser as an example of a heat exchanger to which the brazing joint method of the tube-pin assembly of the heat exchanger of the present invention is applied.

Fig. 2 is a partial perspective view showing a tube-pin portion in which the brazing joint method of the tube-pin assembly of the heat exchanger of the present invention is applied.

3 is an operation diagram showing the application of the brazing joint method of the tube-fin assembly of the heat exchanger of the present invention.

Figure 4 is a perspective view and a front view showing the tube-pin portion joined by the brazing bonding method of the tube-pin assembly of the heat exchanger of the present invention.

FIG. 5 is an enlarged cross-sectional micrograph showing the joint by brazing bonding of the tube-pin assembly of a heat exchanger of the present invention.

* Explanation of symbols used in the main part of the drawing *

C: condenser

2,3: header-header tank assembly

4: tube

5: pin

In view of the problems of the brazing bonding method of the tube-fin assembly of the heat exchanger of the conventional configuration as described above, the brazing bonding method of the tube-fin assembly of the heat exchanger of the present invention has the different processes, thus eliminating the above-mentioned problems, thereby reducing productivity and cost. It aims at making savings possible.

The brazing method of the tube-fin assembly of the heat exchanger of the present invention to achieve this object is;

The tube-pin of the tube-fin assembly of the heat exchanger having a plurality of plate-shaped tubes fluidly connected between the fluid tanks and fins which are zigzag-shaped thin plate bending bodies disposed and fastened between the tubes as a material such as aluminum. It is composed of a bare material that is formed by conventional extrusion molding or press molding, and a slurry mixed with flux and silicon is dissolved in a solvent, sprayed with a spray gun, and brazed by welding. The flux and silicon (Si) are mixed in a 2: 1 weight ratio to form a slurry, and the slurry is mixed with alcohol or water in a 1: 1 weight ratio to form a slurry solvent.

The construction and effect of the brazing joining method of the tube-fin assembly of the heat exchanger of the present invention together with the accompanying drawings will be described in more detail.

1 is an exploded perspective view showing a condenser that is an example of a heat exchanger to which the brazing joint of the tube-pin assembly of the heat exchanger of the present invention is applied, and FIG. 2 is a brazing joint of the tube-fin assembly of the heat exchanger of the present invention to be applied. Fig. 3 is a working view showing the application of the brazing joint of the tube-fin assembly of the heat exchanger of the present invention, and Fig. 4 is the brazing of the tube-fin assembly of the heat exchanger of the present invention. A perspective view and a front view showing the tube-pin section joined by the joining method, FIG. 5 is an enlarged cross-sectional micrograph showing the joint section by the brazing joining method of the tube-pin assembly of the heat exchanger of the present invention.

As an exemplary configuration to which the brazing bonding method of the tube-fin assembly of the heat exchanger of the present invention is applied, as in FIG.

Comprising an entire capacitor (C), the capacitor (C) is a plurality of equally spaced plate-like tube (4) disposed between the header-header tank assembly (2, 3), the fluid receiving portion at both ends and the tube (4) It has a pin (5), which is a zigzag thin plate bending body that is also disposed between and fixed.

Accordingly, the tube 4 and the pin 5 fluidly connecting the header-header tank assemblies 2 and 3 should be firmly welded and have a fixed connection G as shown in FIG. 2.

Conventionally, the outer surface of the tube 4 and the outer surface of the fin 5 to form a clad material having a relatively low melting point compared to the material of the tube 4 and the fin 5 in order to implement the above-described configuration By mechanically assembling each of the above members and putting them in a brazing furnace, the cladding material on the surface of each member is melted to fix each other.

Brazing bonding methods of tube-fin assemblies of such conventional heat exchangers include;

(1) forming of tube-pins

(2) Clad repaint of tube-pin

(3) assembly

(4) Flux spraying after assembly

(5) Brazing melting

Through the multi-steps of the process, the above-mentioned problems such as the complexity of the process, a decrease in productivity, and a cost increase were found.

The following describes the brazing method of tube-fin assembly of the heat exchanger of the present invention.

In the present invention, silicon is mixed as a flux and clad material to simplify the process by including injection.

The commercialized flux and silicon (Si) are mixed in a 2: 1 weight ratio to a slurry state. This slurry is mixed with alcohol or water as a solvent in a 1: 1 weight ratio and sprayed with a spray gun or the like.

In this case, the assembly of the tube and the fin to be spray-coated is a bare material which is formed by conventional extrusion molding or press molding as a material such as unclad aluminum. An embodiment of this welding method will be described.

Example

Flux and silicon (Si) are mixed in a 2: 1 weight ratio to make a slurry (Slury), and then mixed in an alcohol or water in a 1: 1 weight ratio, and evenly sprayed onto an assembly of a tube and a fin formed by using a spray gun.

The sprayed slurry solvent is dried at about 150 degrees Celsius for about 5 minutes to form a coating layer.

Again, the assembly is put into a brazing furnace in a nitrogen (N ₂ ) atmosphere, the temperature rises at a rate of about 90 degrees Celsius / minute, and the junction temperature is raised to 590 degrees Celsius, which is maintained for about 2 minutes to achieve bonding.

Tube-fin assembly of the heat exchanger bonded as an embodiment as described above;

A relatively low viscosity flux solvent penetrates into the tube-pin connection surface and shows a good bonding state. As shown in FIG. 4, it can be seen that uniform bonding is made along the tube-pin connection line.

After cold-mounting the cross section by cutting the junction of the tube-pin formed as said process,

In the cross section observed at a magnification of 50 times, a fillet 6, which is a welded portion formed by bonding, is formed between the tube 4 and the fin 5, and the fillet 6 is formed of an Al-Si process. It can be seen that a strong bond is made as a tissue.

The brazing joining method of the tube-fin assembly of the heat exchanger according to the above method has an advantage as opposed to the above-described conventional method,

By applying the flux solvent, the cladding material required for brazing is supplied so that the cladding material mixed with the flux easily penetrates into the narrow tube-pin connection part.

Uniform connection fixing is achieved overall, thus avoiding the use of expensive cladding materials.

The brazing joining method of the tube-fin assembly of the heat exchanger of the present invention as described above is a useful invention that eliminates problems such as poor bonding, increased air handling, and cost improvement caused by processing as a conventional clad material.

Claims (3)

In a tube-fin assembly of a heat exchanger having a plurality of plate-shaped tubes (4) for fluid connection between fluid tanks and fins (5), which are zig-zag-shaped thin plate bending bodies disposed and assembled between the tubes (4), ; The tube-pin is configured as a bare material which is formed by extrusion molding or press molding, which is common as a material such as aluminum, A method of brazing and joining a tube-fin assembly of a heat exchanger, characterized in that a slurry containing a mixture of flux and silicon (Si) is dissolved in a solvent and sprayed with a spray gun to perform brazing to deposit a tube-fin. The tube-fin assembly of a heat exchanger having a plurality of plate-shaped tubes 4 fluidly connected between the fluid tanks and fins 5, which are zigzag thin plate-folded bodies arranged and assembled between the tubes 4, The tube-pin is made of a raw material made of aluminum such as aluminum by extrusion molding or press molding, and a slurry containing a mixture of flux and silicon is dissolved in a solvent and sprayed. Performing spray coating and brazing to deposit the tube-pin; The flux and silicon (Si) are mixed in a 2: 1 weight ratio to form a slurry, and the slurry is mixed with alcohol or water in a 1: 1 weight ratio to form a slurry solvent. Brazing method of pin assembly. The method according to claim 1 or 2, The slurry solvent applied to the tube-pin is dried at about 150 degrees Celsius for 5 minutes to form a coating layer, and the assembly of the tube-pin is put into a brazing furnace in a nitrogen (N ₂ ) atmosphere to increase the temperature at a rate of about 90 degrees Celsius. Brazing joining method of the tube-fin assembly of the heat exchanger, characterized in that the temperature is raised to 590 degrees Celsius per minute / minute and maintained for about 2 minutes.