JPH0979773A - Manufacture of heat pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it easy to control an amount of working medium fluid in a pipe and make it possible to prevent the working medium from bumping and make it unnecessary to vacuum-degas an interior of the pipe under. SOLUTION: A heat pipe is manufactured by implementing the steps of pouring working medium 2 in a liquid state into a pipe 1 one end of which is closed, closing another end of the pipe 1 in a state in which the working medium 2 is heated to a temperature lower than a boiling point of the working medium 2 to make a closed pipe of the pipe 1, heating the pipe 1 to a temperature not lower than the boiling point of the working medium, cutting and removing top side part of the pipe 1 and closing a cut portion of the pipe 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a heat pipe.

[0002]

2. Description of the Related Art A heat pipe is one in which a large number of grooves are formed on the inner surface of a pipe made of a metal having good thermal conductivity (such as copper) or stainless steel, and a working medium is enclosed in the pipe. By evaporating and condensing the working medium, the heat in the pipe is transferred in the form of latent heat of vaporization from the liquid phase side of the working medium (one end side of the pipe) to the gas phase side of the working medium (the other end side of the pipe). Is to be transported.

An example of a conventional heat pipe manufacturing method is as follows:
2 (a)-(c). First, as shown in FIG. 2A, a groove 9 (not shown, for example, as shown in FIG. 5) is formed on the entire inner surface, and one end (lower end) side is sealed, and is made of, for example, copper or the like. A working medium 2 made of, for example, pure water is injected into the pipe 1 in an amount larger than a desired amount of liquid.

Next, as shown in FIG. 2 (b), this pipe 1 is placed in, for example, a constant temperature bath 4 and heated oil 5 is put in it.
The working medium 2 is heated and maintained at a high temperature above its boiling point (for example, 150 ° C. for pure water) by being immersed in the medium. By evaporating the working medium 2 in the pipe 1 by boiling in this way, the working medium 2 ′ in the gaseous state moves to the upper end side in the pipe 1, and the non-condensable substance 3 such as air existing in the pipe 1 is removed from the pipe 1. You can get out.

Here, in order to completely expel the non-condensable substance 3 from the inside of the pipe 1 in this way, when the heat pipe is completed with the non-condensable substance 3 remaining and the heat pipe is operated, the non-condensable substance 3 is non-condensable. This is because the partial pressure of the working medium 2 on the gas phase side is kept low because of the substance 3, and the heat exchange efficiency by the heat pipe is lowered.

Thus, the non-condensable substance 3 is discharged from the pipe 1.
Finally, as shown in FIG. 2C, the upper end of the pipe 1 is sealed to complete the heat pipe.

Another example of the conventional heat pipe manufacturing method is shown in FIGS. 3 (a) to 3 (e), FIG. 4 and FIG. First, FIG.
(A) As shown in FIG. 4, in the same manner as the above-mentioned one, the vacuum pump 11 and the water supply are provided on the pipe 1 having the groove portion 9 (not shown) formed on the inner surface and having one end (lower end) side sealed. Bowl 12
One end of the conduit 10 that is switchably connected to and is connected. In this state, the path of the pipeline 10 is switched to the vacuum pump 11 side, and the inside of the pipe 1 is evacuated by the vacuum pump 11. Next, the path of the pipe line 10 is switched to the water supply device 12 side, and a working medium 2 made of, for example, pure water is injected into the pipe 1 that is in a substantially vacuum state, as shown in FIG. 3B.
Fill the entire pipe 1.

The vacuum deaeration in the pipe 1 (that is, the suction of the working medium 2) and the filling of the working medium 2 are repeated several times to completely fill the inside of the pipe 1 with the working medium 2.
After the non-condensable substance 3 such as air does not remain in the inside, as shown in FIG. 3C, the inside of the pipe 1 is evacuated again to suck the working medium 2, As it is,
As shown in FIGS. 3D and 3E, the other end (upper end) side of the pipe 1 is sealed by caulking and TIG welding.

Even if the working medium in the pipe 1 is sucked and removed in this way, due to the surface tension between the groove 9 on the inner surface of the pipe 1 and the working medium 2, as shown in FIG. The medium 2 remains in the heat pipe more than necessary. Moreover, since the non-condensable substance 3 does not remain in the pipe 1,
A heat pipe with good heat transfer characteristics can be obtained.

[0010]

However, FIG.
In the method shown in (c), it is necessary to keep the working medium 2 at a high temperature above the boiling point for a long time until the non-condensable substance 3 is completely expelled from the inside of the pipe 1. The working medium 2'in a gaseous state also escapes to the bottom. As a result, it has been difficult to accurately control the liquid amount of the working medium 2 in the pipe 1 with a certain fixed amount.

In this method, it is necessary to control the temperature of not only the pipe 1 but also the working medium 2.
When the working medium 2 at a temperature close to room temperature is injected into the pipe 1 heated to a temperature equal to or higher than the boiling point of the working medium 2, the working medium 2 bumps in the pipe 1 and overflows to the outside of the pipe 1. I will end up. In this method, in particular, the smaller the diameter of the pipe 1, the greater the number of bumping occurrences of the working medium 2 described above. As a result, the liquid amount of the working medium 2 in the pipe 1 is
It became difficult to manage accurately with a certain amount.

Therefore, it was difficult to manufacture heat pipes of the same quality by the method shown in FIGS. 2 (a) to 2 (c).

Further, in the method as shown in FIGS. 3 (a) to 3 (e), FIG. 4 and FIG. 5, since the inside of the pipe 1 is vacuum deaerated,
For example, the work process becomes complicated, such as switching the path of the pipeline 10 between the vacuum pump 11 and the water supply device 12. Moreover, since this is repeated many times, it takes a lot of time and labor until the heat pipe is completed. Was needed.

In addition, in this method, the liquid volume of the working medium 2 remaining in the pipe 1 when the working medium 2 in the pipe 1 is finally vacuum-sucked is the amount of the working medium 2 and the groove 9 on the inner surface of the pipe 1. Since it depends on factors such as surface tension between which it is difficult to control, it was difficult to control accurately with a certain fixed amount. Therefore, it was difficult to manufacture the heat pipes of the same quality as shown in FIGS. 3A to 3E, 4 and 5 with a good yield.

The present invention has been made to solve the above problems, and an object thereof is to easily manage the liquid amount of a working medium in a pipe and prevent bumping of the working medium.
Moreover, it is to provide a method for manufacturing a heat pipe that does not require vacuum deaeration inside the pipe.

[0016]

A method of manufacturing a heat pipe according to the present invention comprises a step of injecting a working medium in a liquid state into a pipe whose one end is sealed, and a temperature of the pipe lower than the boiling point of the working medium. A sealing pipe is produced through a step of sealing the other end side of the pipe in a state where the sealing pipe is heated to a temperature higher than the boiling point of the working medium, and the upper end of the sealing pipe is heated. It is characterized in that a part of the side is cut and removed, and the cutting port of the sealing pipe thus formed is sealed.

In the method for manufacturing a heat pipe of the present invention, first, a working medium in a liquid state is injected into a pipe whose one end side is sealed, and the pipe is heated to a temperature lower than the boiling point of the working medium, Seal the other end of the pipe.

By first heating the pipe in this manner, the working medium in the pipe starts to evaporate from the surface of the liquid layer while remaining in a non-boiling state, and a part of the working medium becomes a gas state. The non-condensable substance in the inside is exhausted through the upper end side of the pipe while being pushed by the working medium in the gaseous state. Also, after this, since the upper end side of the pipe is sealed to make this pipe a sealed pipe,
The inside of the pipe is almost filled with the working medium in the gas state and the liquid state, so that the amount of the non-condensable substance remaining in the pipe is very small, if any.

Therefore, in order to expel even a very small amount of the non-condensable substance from the inside of the pipe, the pipe is heated to a temperature equal to or higher than the boiling point of the working medium. As a result, the partial pressure of the working medium in the gaseous state increases, and the non-condensable substance remaining in the pipe stays in the compressed upper state inside the pipe. In this state, a part of the upper end of the pipe is cut and removed to remove the non-condensable substance from the pipe. Then, by sealing the cut opening of the pipe thus formed, the pipe is again made into a sealed pipe.

As described above, the non-condensable substance remaining in the pipe can be easily removed to the outside of the pipe to manufacture a high quality heat pipe. Moreover, according to this method, the liquid amount of the working medium in the pipe hardly changes from the time when the working medium is injected into the pipe, so that the liquid amount can be easily controlled.

Further, in the present invention, as in the conventional case,
Since there is no need to degas the inside of the vacuum tube, the heat pipe can be manufactured with almost no complicated work.

In addition, in the present invention, while the upper end side of the pipe is open, the work is carried out while the pipe is not heated above the boiling point of the working medium, so the working medium is injected into the pipe at room temperature. However, the possibility that the working medium bumps and scatters outside the pipe is reduced.

In the present invention, however, the step of heating the pipe to a temperature lower than the boiling point of the working medium may be before or after the step of injecting the working medium into the pipe. The point is that the pipe is heated in such a manner. Then, it suffices if the other end of the pipe can be sealed.

Further, a step of cutting and removing a part of the upper end side of the pipe in a state where the pipe is heated to a temperature equal to or higher than the boiling point of the working medium, and a step of sealing a cutting port of the pipe formed thereby That is, it is preferable to perform the operation quickly without providing a time interval because the amount of the gaseous working medium in the pipe leaking out of the pipe is reduced.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1A to 1D show a method of manufacturing a heat pipe, which is an example of an embodiment of the present invention. First, as shown in Fig. 1 (a), a pipe 1 (for example, made of copper, having an inner diameter of 2.) that has a groove 9 (not shown; for example, as shown in Fig. 5) sealed on the lower end side is formed.
5 mm, length 320 mm) is heated to a predetermined temperature (for example, 98 ° C. for pure water) below the boiling point of the working medium 2 described later by, for example, immersing in heated oil 5 in a constant temperature bath 4, In that state, a proper amount (for example, 0.3 cc) of the working medium 2 made of, for example, pure water was quantified and injected into the pipe 1 at room temperature. However, the working medium 2 is heated to 98 ° C. in advance, and thereby the dissolved gas is removed from the inside.

A sensor 7 attached to the water vapor sensor 6 is attached near the opening on the upper end side of the pipe 1, and the working medium 2 '(water vapor) near the opening is attached by the sensor 7. The temperature of the pipe 1 was maintained at the above-mentioned predetermined temperature while checking the presence or absence of the above condition as needed. As a result, the working medium 2 in the pipe 1 rises in temperature and evaporates, and the working medium 2 ′ in the gas state expels the non-condensable substance 3 remaining in the pipe 1 out of the pipe 1.

Thus, as shown in FIG. 1B, when the working medium 2'in a gaseous state rises from the inside of the pipe 1 and the water vapor sensor 6 and the sensor 7 sense the working medium 2 ', That is, as soon as the non-condensable substance 3 has almost disappeared in the pipe 1, as shown in FIG.
The upper end side of the pipe 1 was sealed, and this pipe 1 was used as a sealed pipe.

Next, the pipe 1 whose inside is sealed is heated to 150 ° C. (above the boiling point of pure water) by, for example, a block heater 8. In this way, the non-condensable substance 3 remaining in the pipe 1 was retained at the upper end side inside the pipe 1. However, a pipe 1 in the same internal sealed state was manufactured in advance, and by examining this, it was found that the non-condensable substance 3 stays within about 15 mm from the uppermost end in the pipe 1. ing.

Therefore, based on this result, as shown in FIG. 1 (d), the pipe 1 is temporarily sealed at a distance of 20 mm from the upper end side, for example, by caulking, and then the upper end side at that portion. Cut off. And finally, for example, TIG
The temporarily sealed portion (cutting port) of the pipe 1 was completely sealed by welding or the like to obtain a sealed pipe again.

The heat pipe (inner diameter 2.5 mm, length 300 mm) produced as described above has excellent heat transfer characteristics, and heat pipes of the same quality can be produced with good yield under the same production conditions. I was able to.

Here, in the example of the present embodiment, the pipe 1 is made of copper and the working medium 2 is pure water. However, in the present invention, the material of the pipe 1 and the working medium 2 are different. The component may be any as long as it is used as a heat pipe.

In the example of this embodiment, the pipe 1
Was preheated to a temperature close to and lower than the boiling point of the working medium 2, but in the present invention, the heating temperature of the pipe 1 does not necessarily have to be close to the above-mentioned boiling point.

Further, in the example of the present embodiment, if the time required from the injection of the working medium 2 into the pipe 1 to the sealing of the upper end side of the pipe 1 is recorded and managed, the heat will be applied from the next time. When manufacturing a pipe, it is preferable to seal the upper end side of the pipe 1 by using the above-mentioned required time as a guide.

In addition, in the example of the present embodiment, the length 30
An example of manufacturing one 0 mm heat pipe was shown.
In the same manner as in the above case, for example, a long heat pipe having a length of 3000 mm or the like is manufactured, and the heat pipe is made to have a horizontal direction in its longitudinal direction. It is also possible to manufacture the heat pipes collectively, such as forming a pipe.

[0035]

According to the method of manufacturing a heat pipe of the present invention, since the liquid amount of the working medium in the pipe hardly changes from the time when the working medium is injected into the pipe, the liquid amount management is easy. is there. Further, according to the present invention, there is no need to degas the inside of the pipe under vacuum unlike the conventional case, so that the heat pipe can be manufactured with almost no complicated work. In addition, in the present invention, while the upper end side of the pipe is open, the work is carried out in an atmosphere having a temperature lower than the boiling point of the working medium, so that the working medium can be prevented from bumping and scattering outside the pipe.

[Brief description of drawings]

FIG. 1A, FIG. 1B, FIG. 1C, and FIG. 1D are explanatory views showing each step in a heat pipe manufacturing method as an example of an embodiment of the present invention.

2A, 2B, and 2C are explanatory views showing each step in an example of a conventional method for manufacturing a heat pipe.

3 (a), (b), (c), (d), (e).
Explanatory drawing which shows each process in the other example of the manufacturing method of the conventional heat pipe.

FIG. 4 is a diagram showing exhaust and water supply paths for manufacturing the heat pipe shown in FIG.

5 is an enlarged vertical sectional view of a part of the pipe shown in FIG.

[Explanation of symbols]

 1 Pipe 2 Working Medium (Liquid) 2'Working Medium (Gas) 3 Non-Condensable Substance 4 Constant Temperature Bath 5 Oil 6 Water Vapor Detector 7 Sensor 8 Block Heater 9 Groove 10 Pipeline 11 Vacuum Pump 12 Water Supplyer

Claims (1)

[Claims] 1. A step of injecting a working medium in a liquid state into a pipe whose one end is sealed, and sealing the other end of the pipe while the pipe is heated to a temperature lower than the boiling point of the working medium. To produce a sealed pipe through the steps of heating the sealed pipe to a temperature above the boiling point of the working medium,
A method for manufacturing a heat pipe, characterized in that a part of an upper end side of the sealing pipe is cut and removed, and a cutting port of the sealing pipe thus formed is sealed.