JP2005007433A - Method for manufacturing finned tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the manufacturing cost and to prevent the development of looseness in winding when a finned tube composed of an aluminum-made hoop-state fin base stock 2 constituting the fin 3 on the outer peripheral surface of a titanium-made heat transmitting tube 1 is manufactured by continuously winding as a spiral-state. <P>SOLUTION: To the heat transmitting tube 1, the starting end part 2a and the finishing end part 2b of the fin base stock 2, are brazed by using a brazing filler metal composed of silver, or containing silver as the main component, in an inert gas atmosphere at least near this starting end part and the finishing end part by filling the inert gas into the heat transmitting tube. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a fin tube in which a large number of aluminum heat dissipating fins are provided on the outer periphery of a titanium heat transfer tube.
[0002]
[Prior art]
Patent Document 1 as a prior art describes a manufacturing method in which a hoop-shaped (band-shaped) fin material is continuously wound in a spiral shape around the outer periphery of a heat transfer tube when manufacturing this type of fin tube. Yes.
[0003]
This prior art is a method in which a hoop-shaped fin material is continuously wound in a spiral shape around the outer periphery of the heat transfer tube, and the fin material is welded to the heat transfer tube by high-frequency resistance welding or the like. The heat tube and fin can be easily applied in the case of materials that can be welded together.
[0004]
However, when the heat transfer tube is made of titanium for the purpose of enhancing the corrosion resistance and heat dissipation in the fin tube as in the present invention, both the titanium and aluminum are high when the fin is made of aluminum. In addition to being extremely oxidative at temperature, they do not melt together and cannot be welded together. As in the prior art, the fin material is spirally wound around the heat transfer tube. However, it is not possible to employ the method of welding.
[0005]
Therefore, while manufacturing the heat transfer tube made of titanium while the fin tube made of aluminum fins, the starting end portion of the fin material made into a hoop shape with aluminum is made to the titanium heat transfer tube with these. Is fixed using a separate metal fitting, and in this state, the fin material is continuously wound in a spiral shape in close contact with the outer peripheral surface of the heat transfer tube, and its end portion is attached to the heat transfer tube. In addition, a method of fixing by using a metal fitting separately formed from these is adopted.
[0006]
As described above, when loosening of the fin material is wound around the heat transfer tubes, the adhesion of the fins to the heat transfer tubes decreases, and consequently, the heat transfer coefficient between them decreases. The starting end portion and the terminal end portion of the wound fin material must be fixed to the heat transfer tube so as not to loosen the winding of the fin material.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-254642
[Problems to be solved by the invention]
However, in the past, the starting end and the terminal end of the wound fin material that has been wound are fixed using a separate metal fitting, so that the winding is not loosened. In particular, there is a problem that not only a great deal of labor and skill are required, but there is a slight slack in winding.
[0009]
In addition, due to the use over many years, loosening due to corrosion or the like is likely to occur due to corrosion by the metal fitting, and when loosening occurs in this fixed part, the winding of the fin material is loosened, and the adhesiveness related to the heat transfer tube is reduced. This leads to a situation in which the heat transfer coefficient between them decreases.
[0010]
In addition, conventionally, since a separate metal fitting is required, the number of parts increases, leading to an increase in manufacturing cost and weight, and a problem of deterioration in appearance.
[0011]
An object of the present invention is to provide a manufacturing method that solves these problems.
[0012]
[Means for Solving the Problems]
In order to achieve this technical problem, claim 1 of the present invention provides:
“At least a step of continuously winding a hoop-shaped fin material made of aluminum that constitutes a fin around the outer peripheral surface of a titanium heat transfer tube in a spiral shape, and the heat transfer tube with the start end portion of the fin material being applied to the heat transfer tube Brazing using a brazing material containing silver or silver as a main component in a state where an inert gas is filled in the tube and an atmosphere of an inert gas is provided at least in the vicinity of the starting end, and termination of the fin material Using a brazing material mainly composed of silver or silver in a state where an inert gas is filled in the heat transfer tube with respect to the heat transfer tube, and at least the vicinity of the terminal portion is in an inert gas atmosphere And brazing. "
It is characterized by that.
[0013]
Further, claim 2 of the present invention provides
In the description of claim 1, the brazing at the start end and the brazing at the end are performed by generating an arc between the electrodes in an inert gas flow blown against the start end and the end. It ’s brazing. ”
It is characterized by that.
[0014]
[Operation and effect of the invention]
By fixing the start and end portions of the fin material wound around the heat transfer tube to the heat transfer tube by brazing using silver or a brazing material containing silver as a main component, silver or Since the brazing material mainly composed of silver is metal-bonded to both the titanium heat transfer tube and the aluminum fin material, the fin material can be firmly fixed to the heat transfer tube.
[0015]
In addition, by performing the brazing described above in an inert gas atmosphere, the outer peripheral surface of the heat transfer tube and the surface of the fins can be prevented from being oxidized. Decrease in heat dissipation and corrosion resistance, and discoloration can be reliably reduced.
[0016]
Moreover, since the inner surface of the heat transfer tube can be prevented from being oxidized by filling the heat transfer tube with an inert gas during the brazing described above, the heat dissipation and corrosion resistance are reduced due to the oxidation of the heat transfer tube inner surface. Can be reliably reduced.
[0017]
Thus, according to the present invention, the start and end portions of the fin material wound around the outer peripheral surface of the heat transfer tube made of titanium are brazed to the heat transfer tube so that the heat dissipation and corrosion resistance of the heat transfer tube and the fin are reduced. Since it can be firmly and firmly fixed without deteriorating or discoloring, it is possible to reliably reduce the occurrence of slack in the winding of the fin material as in the past, and to reduce the external shape. In addition, there is an effect that the number of parts can be reduced without requiring a separate metal fitting as in the prior art, the manufacturing cost can be reduced, and the weight can be reduced.
[0018]
In particular, according to the claims, the inert gas atmosphere can be formed in the vicinity of the portion to be brazed by spraying the inert gas. There is an advantage that the cost can be further reduced by reducing the amount of the atmosphere.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings of FIGS.
[0020]
In these drawings, reference numeral 1 denotes a heat transfer tube made of titanium, reference numeral 2 denotes a fin material 2 which is made of aluminum and has a long hoop shape with an L-shaped cross section, and the fin material 2 is indicated as the heat transfer tube. A fin tube 4 is formed by continuously winding the outer periphery of 1 in a spiral shape to form the fin 3.
[0021]
When the fin material 2 is wound around the heat transfer tube 1, the starting end 2a of the fin material 2 is brought into contact with the outer peripheral surface of the heat transfer tube 1 as shown in FIGS. In the state, it adheres by brazing by the method mentioned later. In addition, the build-up in this brazing is shown with the code | symbol 5. In FIG.
[0022]
As shown in FIG. 2, the brazing is performed by using a brazing head 6 in which a tungsten electrode 6b is provided inside a gas nozzle 6a for injecting an inert gas such as argon gas. 2 by approaching the starting end 2a and applying a direct current between the tungsten electrode 6b and the heat transfer tube 1 and the fin material 2, an arc is generated in an inert gas flow atmosphere ejected from the gas nozzle 6a. It is generated by melting a brazing material containing 99% silver or a brazing material 7 mainly composed of silver such as BAg-8 according to JIS standards.
[0023]
Further, when brazing at the starting end 2a, the inside of the heat transfer tube 1 is filled with an inert gas such as argon gas.
[0024]
In this way, when the starting end 2a of the fin material 2 is fixed to the heat transfer tube 1 by brazing, the heat transfer tube 1 and the fin material 2 are rotated while the heat transfer tube 1 is rotated as shown in FIG. By moving either one or both relatively in the axial direction of the heat transfer tube 1, the fin material 2 is continuously wound around the outer periphery of the heat transfer tube 1 in a spiral shape.
[0025]
In this winding, the fin material 2 is made to be in close contact with the heat transfer tube 1 by strengthening the winding.
[0026]
Next, as shown in FIG. 6, the end portion 2 b of the fin material 2 is held in the same manner as described above with the strong heat wrapping of the fin material 2 around the heat transfer tube 1 around the heat transfer tube 1. The brazing head 6 is fixed by brazing using a brazing material containing 99% silver or a brazing material 7 mainly composed of silver such as BAg-8 according to JIS standard. The build-up at the time of brazing is indicated by reference numeral 8.
[0027]
Also, when brazing at the end portion 2b, the inside of the heat transfer tube 1 is filled with an inert gas such as argon gas.
[0028]
As described above, the brazing material 7 containing silver or silver as a main component is used to fix the start end portion 2a and the end end portion 2b of the fin material 2 wound around the heat transfer tube 1 to the heat transfer tube 1. By performing brazing, silver or the brazing material 7 containing silver as a main component is metal-bonded to both the heat transfer tube 1 made of titanium and the fin material 2 made of aluminum. Therefore, the fin material 2 is used as the heat transfer tube. 1 can be firmly fixed to 1.
[0029]
When the brazing is performed, the vicinity of the start end portion 2a and the end end portion 2b of the fin material 2 and the inside of the heat transfer tube 1 are in an atmosphere of an inert gas such as argon gas. Since the oxidation of the material 2 is suppressed, the brazing described above can be performed reliably.
[0030]
According to the experiment, when brazing in the above-described embodiment, the applied direct current is 30 to 50 (Amp.) And the voltage is 15 to 20 (V), while the argon gas from the gas nozzle 6a is used. The amount of squirting was set to 15 to 20 (liters per minute), and the brazing could be performed in a preferable state by using a brazing material 7 of BAg-8 with a wire diameter of 1.6 mm according to JIS standards. .
[0031]
In the embodiment, first, the start end 2a of the fin material 2 is brazed to the heat transfer tube 1, and then the end portion 2b is brazed to the heat transfer tube 1 after the fin material 2 is wound. However, the present invention is not limited to this order, and the fin material 2 is wound around the heat transfer tube 1 first, and both the start end 2a and the end end 2b are held in the wound state. May be brazed to the heat transfer tube 1.
[Brief description of the drawings]
FIG. 1 is a view showing a state in which a starting end portion of a fin material is brazed to a heat transfer tube.
2 is a diagram showing a state of brazing in the sectional view taken along the line II-II of FIG. 1;
FIG. 3 is a view showing a state in the middle of winding a fin material around a heat transfer tube.
FIG. 4 is a view showing a state in which a fin material is wound around a heat transfer tube.
5 is a longitudinal front view of FIG. 4. FIG.
6 is a diagram showing a state of brazing in a cross-sectional view taken along line VI-VI in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Heat-transfer tube 2 Fin material 2a Fin material start part 2b Fin material end part 3 Fin 4 Fin tubes 5 and 8 Brazing build-up part 6 Brazing head 7 Brazing material

Claims (2)

At least a step of continuously winding a hoop-like fin material made of aluminum constituting a fin around the outer peripheral surface of a heat transfer tube made of titanium in a spiral shape;
Silver or silver will be the main component in a state in which the start end of the fin material is filled with an inert gas in the heat transfer tube with respect to the heat transfer tube, and at least the vicinity of the start end is in an inert gas atmosphere. Brazing using a material,
Silver or silver will be the main component with the end portion of the fin material filled with an inert gas in the heat transfer tube and at least the vicinity of the end portion in an inert gas atmosphere. Brazing using a material,
The manufacturing method of the fin tube characterized by comprising. In the description of claim 1, the brazing at the start end and the brazing at the end are performed by generating an arc between the electrodes in the inert gas flow blown against the start end and the end. A method of manufacturing a fin tube, characterized by being attached.

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