JPH0577039A - Manufacture of header pipe for heat exchanger - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the adhesion between the header pipe and the heat exchange pipe, prevent the heat exchange medium from leaking, and prevent the header pipe from deforming due to brazing filler metal etc. [Structure] After forming a heat exchange tube insertion hole 4 in the header pipe 1, the header pipe 1 is conveyed by a conveying means 7,
The brazing material 5 is sprayed from the spray nozzle 8 toward the insertion hole portion of the header pipe 1 and the peripheral surface of the header pipe 1 being conveyed. As a result, the brazing material 5 is uniformly clad on the inner surface 4a of the insertion hole 4 of the header pipe 1 and the hole peripheral surface portion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a header pipe for a heat exchanger, and more particularly to a method for manufacturing a header pipe for a heat exchanger for brazing a heat exchange pipe.

[0002]

2. Description of the Related Art For example, as a heat exchanger used in an air conditioner for automobiles or households, as shown in FIG. 4, a pair of header pipes 1, 1 and a connection between these header pipes 1, 1 are connected. A plurality of flat heat exchange tubes 2,
2 and a heat exchange fin 3 arranged between the heat exchange tubes 2 and 2 are known. In the heat exchanger configured as described above, conventionally, a brazing sheet in which a brazing material is clad on both sides or one side is used as the header pipe 1 as an electric resistance welded pipe or a welded pipe. Then, in order to assemble the heat exchange pipe 2 to the header pipe 1, after forming it into an electric resistance welded pipe or a welded pipe, a flat heat exchange pipe insertion hole 4 as shown in FIG. The heat exchange tube 2 was inserted into the heat exchanger 4 and brazed together with the heat exchange fins 3.

[0003]

However, in the conventional header pipe 1 for a heat exchanger of this type, the brazing filler metal 5 is cladded over the entire surface of the header pipe 1, so that the heat exchange pipe insertion hole 4 is not covered. Not only is the brazing material 5 at a distant position unnecessary, but also the flow in the direction of gravity during brazing in the furnace causes a brazing material pool 6 as shown in FIG. There was a problem of becoming a thing. Further, when the heat exchange tube insertion hole 4 is formed by press working, as shown in FIG. 7, there is no brazing filler metal in the contact portion between the heat exchange tube 2 and the inner surface of the heat exchange tube insertion hole 4. However, there is a serious problem that a brazing filler metal is defective and a heat exchange medium such as a refrigerant leaks.

As a method of solving the above problem, it is conceivable to place a brazing filler metal on the connecting portion of the heat exchange pipe 2 to the header pipe 1, but in this method, a large number of heat exchange pipes 2 are used.
Since brazing filler metal has to be placed in all of the above, a large amount of labor and time are required, and there is a problem that work efficiency is reduced.

The present invention has been made in view of the above circumstances, and is a method for manufacturing a header pipe for a heat exchanger, which improves the adhesion between the header pipe and the heat exchange pipe by a simple operation and also improves the heat exchange performance. It is intended to provide.

[0006]

In order to achieve the above object, a method of manufacturing a header pipe for a heat exchanger according to the present invention comprises:
The brazing material is sprayed onto the inner surface of the heat exchange tube insertion hole of the header pipe and the peripheral surface of the heat exchange tube insertion hole.

In the present invention, any method may be used for spraying the brazing material. For example, a spray gun for spraying the brazing material may be fixed, and the header pipe may be moved to move the brazing material to the inner surface of the heat exchange tube insertion hole and heat. The peripheral surface of the exchange tube insertion hole may be sprayed, or the header pipe may be fixed and the spray gun may be scanned. Further, both may be moved to spray the brazing material. In this case, the positional relationship between the header pipe and the spray gun may be arbitrary, but it is preferable to dispose the spray gun on the upper side of the header pipe and spray the brazing material from the upper side.

Examples of the brazing material include Zn-Al alloys, Zn alloys, Cd-Zn alloys, in addition to Al-Si alloys.
Sn-Zn alloy, Sn-Pb alloy, etc. can be used. Further, by spraying Si fine powder in addition to the brazing material, Si of the sprayed portion may be alloyed with Al of the base material at the brazing temperature to perform brazing.

[0009]

[Operation] After a hole for heat exchange pipe insertion is drilled in a header pipe not clad with a brazing filler metal, the brazing filler metal is inserted by a spray gun or the like into the inner surface of the heat exchange pipe insertion hole of the header pipe and the heat exchange pipe insertion. By spraying around the hole,
A sufficient amount of brazing material can be attached to the heat exchange pipe connection portion of the header pipe. Further, since the brazing material is not attached to other than the connecting portion of the heat exchange pipe, the brazing material does not flow due to gravity during brazing in the furnace to form a brazing material pool. Furthermore, even when the heat exchange tube insertion hole is formed by press working, a sufficient amount of brazing material can be attached to the inner surface of the heat exchange tube insertion hole.

[0010]

Embodiments of the present invention will be described in detail below. Since this embodiment is a method of manufacturing the header pipe for the heat exchanger shown in FIG. 4, the same parts will be described with the same reference numerals.

FIG. 1 is a schematic perspective view showing a state in which a brazing material is attached to a header pipe according to the present invention. In FIG. 1, reference numeral 7 is a conveying means for conveying the header pipe 1, which is formed of, for example, a belt conveyor. Two spraying nozzles 8 for spraying the brazing material 5 toward the header pipe 1 are arranged above the carrying means 7 so as to be swingable along the carrying direction of the header pipe 1.

In order to clad the brazing filler metal 5 on the header pipe 1, first, a flat heat exchange pipe insertion hole is provided at an appropriate interval on the heat exchange pipe connecting side surface of the header pipe 1 where the brazing filler metal is not clad. 4 (hereinafter referred to as an insertion hole) is drilled. Next, the header pipe 1 is placed on the conveying means 7 with the insertion hole 4 on the upper side and conveyed, and the brazing material is sprayed from the upper side of the header pipe 1 during conveyance by the spray nozzle 8 to insert the insertion hole. The brazing material 5 can be clad around the inner surface 4 a of the metal plate 4 and the periphery of the insertion hole 4.

In this way, as shown in FIG. 2, the heat exchange tube 2 is moved toward the insertion hole 4 of the header pipe 1 in which the brazing material is clad on the inner surface 4a of the insertion hole 4 and the peripheral surface of the insertion hole 4. By inserting and brazing in the furnace together with the fins 3 for heat exchange, the header pipe 1 and the heat exchange pipe 2 can be brazed, and the heat exchanger can be assembled. At this time, as shown in FIG. 3, the brazing filler metal 5 is uniformly clad on the inner side surface 4a of the insertion hole 4 and the peripheral surface thereof, so that the brazing filler metal 5 of the header pipe 1 and the heat exchange tube 2 adhere Is good,
Brazing becomes reliable. Further, since the brazing filler metal 5 is not clad at a position away from the periphery of the insertion hole 4, the brazing filler metal does not flow down due to gravity during brazing in the furnace to form a brazing filler metal pool, which does not deform the header pipe 1.

Next, the experimental results of the brazing of the header pipe in the present invention will be described.

Experimental conditions ★ Shape of header pipe 1 ・ Diameter: 20 mm ・ Thickness: 1.2 mm ・ Material: A3003 extruded tube ・ Length: 320 mm ★ Heat exchange tube insertion hole 4 ・ Number of holes: 30 ・ Hole shape : 16mm × 2mm ・ Hole pitch: 10mm ★ Spraying method ・ Brazing material: Al (12%)-Si (powder) alloy ・ Atmosphere: In air ・ Spraying pressure: 50psi ・ Spraying voltage: 30V ・ Spraying current: 160A ・ Spraying gun : 2 ・ Header pipe speed: Moved under 2 spray guns at 10 mm / sec. When an experiment was conducted under the above conditions, header pipe 1
800-1000 μm around the outer surface of the substrate, that is, around the insertion hole 4.
Of Al-Si brazing material was formed on the inner surface 4a of the insertion hole 4.

Further, the header pipe 1 in which the Al-Si brazing material 5 is clad as described above is brazed at a temperature of 600 ° C. using a fluoride-based flux in a furnace in a nitrogen atmosphere. However, the number of leaks from the brazing portion between the header pipe 1 and the heat exchange pipe 2 was 0 in 100. (In the conventional example, leakage of 3 to 5% occurred.) Further, the brazing filler metal 5 accumulated in the lower portion of the header pipe 1 was 1
It was 0 out of 00 cars. (In the conventional example, almost 100% brazing filler metal pool 6 was generated.)

[0017]

As described above, according to the present invention, the brazing material can be uniformly clad on the inner side surface of the header pipe for inserting the heat exchange tube and the inner side surface and the hole peripheral surface. Adhesion between the brazing filler metal part of the pipe and the heat exchange pipe can be improved, and the header pipe and the heat exchange pipe are brazed securely, preventing the heat exchange medium from leaking from the brazing part. can do. In addition, the brazing material can be clad only in the parts required for brazing, and the brazing material is not clad except in the brazing part.
The efficiency of brazing work can be improved, waste of brazing material can be saved, and the header pipe can be prevented from being deformed due to the accumulation of brazing material during brazing in the furnace.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a brazing state of a header pipe according to the present invention.

FIG. 2 is a perspective view showing a connected state of a header pipe and a heat exchange pipe.

FIG. 3 is an enlarged cross-sectional view of a portion of the header pipe of the present invention in which a brazing material is clad.

FIG. 4 is a front view showing a heat exchanger.

FIG. 5 is a perspective view showing a connected state of a conventional header pipe and a heat exchange pipe.

FIG. 6 is a schematic cross-sectional view showing a conventional brazing state of a header pipe and a heat exchange pipe in a furnace.

FIG. 7 is an enlarged sectional view of a portion of a conventional header pipe in which a brazing material is clad.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Header pipe 2 Heat exchange pipe 4 Insertion hole (hole for heat exchange pipe insertion) 4a Inner surface 5 Brazing material 7 Conveying means 8 Thermal spray nozzle

Claims (1)

[Claims] 1. After forming a heat exchange tube insertion hole in the header pipe, a brazing material is sprayed onto the inner surface of the heat exchange tube insertion hole of the header pipe and the peripheral surface of the heat exchange tube insertion hole. A method for manufacturing a header pipe for a heat exchanger, which is characterized.