JPH03110392A - Heat pipe - Google Patents

Abstract

PURPOSE:To determine abnormal rise of inner pressure based on the an external appearance and to gradually leak operating fluid in a plenty of time if a flat superposed part is damaged by so pressurizing at least a part of a small- diameter cylinder in a state that a connection port for connecting the interior of a tube to the cylinder remains that the wall surfaces are superposed to each other to form a thin flat superposed part. CONSTITUTION:A small-diameter cylinder 3 is formed at the end of a tube 1 by contracting, a thin flat superposed part 5 so caulked into a flat shape that wall surfaces superposed to each other are formed on parts at a predetermined distance from the end of the tube 1 side of the cylinder 3, and the end 5a of the part 5 is brazed by a brazing material 7 and sealed. When the inner pressure of the tube 1 is abnormally raised, the pressure is transmitted to the superposed part 5b of the part 5 through a connection port 9 for connecting the tube interior 1 to the cylinder 3 to gradually open the superposed part, and the part 5 is swelled. Thereafter, when the pressure is further raised, the part 5 is damaged, and operating fluid is gradually leaked in a plenty of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention (1) relates to a heat pipe in which a working fluid circulates within a sealed tube to transport heat.

[Prior Art 1] Conventionally, how to seal off the end of the tube body in such a heat pipe has been a major problem, and various proposals have been made. As an example of this, the end of the tube is embossed to provide a small diameter cylindrical portion for injecting and degassing the working fluid;
A heat pipe is known in which the tip of the small-diameter cylindrical portion is heated and welded to seal it (eg.
Publication No.).

By the way, in such a heat pipe (above), if the internal pressure rises abnormally, some part of the small-diameter cylinder part may break and the working fluid spouts out to the outside. A heat pipe has been proposed that has a thin-walled part that opens when it breaks, making it possible to know in advance the location and direction from which the working fluid will eject, thereby preventing damage to people or property. ("Heat pipe" described in Japanese Patent Application Laid-Open No. 62-245086).

[Problems to be Solved by the Invention] However, even in conventional heat pipes that have such thin walled parts, if the pressure in one part of the heat pipe exceeds a predetermined pressure, the thin walled parts will break down without any warning. damaged,
There was still the problem that the working fluid suddenly spouted out to the outside, and there was a problem that the safety was not sufficient.
With a conventional heat pipe, thin cracks may occur in the thin wall part due to excessive pressure rise and the working fluid may spout to the outside, but since there is little change in appearance, it can be visually confirmed that the heat pipe has failed. Therefore, if the user of the heat pipe misses the ejection of the working fluid for some reason, the user of the heat pipe continues to use the heat pipe without noticing that it has failed. This was done in view of the problem,
Avoid sudden ejection of working fluid, improve safety, and
The purpose is to provide a heat pipe with high maintainability against failure detection.

[Means for Solving the Problems] In order to achieve the above object, the present invention adopts the following configuration as a means for solving the problems. Namely, the end of the tube is connected to the inside of the tube and the other end is connected to the inside of the tube. In a heat pipe that is closed by providing a sealed small-diameter cylindrical portion, at least a portion of the small-diameter cylindrical portion is formed such that the wall surfaces thereof overlap each other, while leaving a communication opening that communicates the inside of the tube with the small-diameter cylindrical portion. This is the structure of a heat pipe characterized by forming a thin flat overlapping portion by applying pressure.

[Function] In a heat pipe configured as described above (Table 1), when the pressure inside the tube increases abnormally, the pressure is absorbed through the communication port that communicates the inside of the tube with the small diameter cylinder. It is transmitted to the overlapping part of the flat overlapping part that follows.As a result, since the flat overlapping part has a thin wall, as the pressure inside the tube increases, the overlap of the flat overlapping part is gradually opened and the flat overlapping part expands. , Then, when the pressure increases further, it acts to damage the thin-walled flat overlying part. That is,
As the pressure increases, the flat polymerized portion is temporarily deformed (expanded) and then breaks. In addition, even if the flat overlapping part is damaged, the working fluid flowing out from the communication port will flow through the gap in the flat overlapping part that has been opened, so the flow rate will not be that high, so fluid will not leak from the damaged part. , it erupts gradually over time rather than suddenly.

In addition, the pipe body A as shown in FIGS. 5(a) and (b)
A beat having a structure in which the small diameter cylindrical part formed in 1 is pressurized from the root on the side of the pipe body A1 to form a flat overlapping part A2 without leaving a communication port that communicates the inside of the pipe body A with the small diameter cylindrical part. In the pipe (friend), the inner side A3 of the tube body A1 on the side of the flat overlapping part A2 has a hemispherical shape and does not have a communication port as described above, and therefore,
The pressure inside the tube body A1 is not transmitted to the overlapping portion of the flat overlapping portion A2, and the unique functions and effects of the present invention as described above are not achieved.

Examples] Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1(a) is a plan view showing a sealed portion of a heat pipe according to a first embodiment of the present invention. FIG. 1(b) is a sectional view taken along line A--A in FIG. 1(a).

In these figures, ] is the tube body as the main body of the heat pipe, and in this example, it is made of a molded copper material with an outer diameter of 12.7 nm, a wall thickness of 0.8 mm, and a length of 250 mm.
It is cylindrical. At the end of such tube body 1 (front
Outer diameter 3~41Tr11. Length 3-4mm
Further, the small diameter cylindrical portion 3 of the small diameter cylindrical portion 3 is formed.
1 mm from the end of tube 1 (at least 0.5
A thin wall (thickness of 0.68 mm or more is required) is caulked into a flat shape so that the wall surfaces overlap each other.
~0. A flat overlapping portion 5 of 78 mm) is formed.

The end portion 5 a Jj of the flat overlapping portion 5 is brazed and sealed with a brazing filler metal 7 . Note that since the caulked portion (flat overlapping portion 5) of the small diameter cylindrical portion 3 is located 1 mm away from the end of the tube (as described above), there is no communication with the inside of the tube of the small diameter cylindrical portion 3. Mouth 9 (Top) It is left as it is without being pickled.

A heat pipe constructed in this manner (after forming a small diameter cylindrical part 3 at the end of the pipe body 1 by drawing, from the small diameter cylinder part 3 to the pipe body) there is a working fluid (in the case of this example, pure water) inside the heat pipe.
The working fluid is boiled using a boiling method, and then the flat overlapping portion 5 is caulked to form the end portion 5.
It is sealed in the procedure of brazing a.

How the heat pipe configured as described above operates in response to an abnormal increase in internal pressure will be described below.

Tube] When the internal pressure rises abnormally, the pressure is released through the communication port 9 that communicates the inside 1 of the tube and the small diameter cylindrical portion 3.
It is transmitted to the overlapping portion 5b of the flat overlapping portion 5 following the communication port 9. As a result, the flat overlapping portion 5 has a thin wall, as shown in FIG. 2(a).

As shown in (b), as the pressure increases, the overlap of the flat overlapping parts 5 is gradually opened, and the flat overlapping parts 5 swell.

Thereafter, when the pressure increases further, the thin flat overlapping portion 5 is damaged, and the working fluid gradually leaks from the damaged portion over time.

According to the inventor's experiments, the number of test pieces is 2.
The heating temperature of both heat pipes is 370-390°C
Then, the flat polymerized part 5 swelled, and its appearance became clearly deformed.
The working fluid leaked slowly from the swollen flat polymerized portion 5 at 1 to 437°C over a period of 5 seconds to 2 minutes and 16 seconds.Also, even after the leakage, the flat polymerized portion 5 remained in a swollen appearance. Therefore, with the heat pipe of this embodiment configured as described above, [f.
The abnormal pressure increase can be determined from the appearance, and as a result, damage to humans or property can be prevented, resulting in excellent safety. Moreover, even if the abnormal pressure rise continues and the flat overlying section 5 is damaged, the working fluid will not leak outside rapidly but will gradually leak over time, resulting in even greater safety. ing.

Further, if the working fluid leaks, the flat overlapping portion 5 always bulges and deforms, so failure of the human pipe can be determined just by looking at the appearance, and maintenance is excellent in terms of early detection of failure.

In the above example, the thickness of the flat overlapping portion 5 was set to 0.6
8 to 0.78 m The length of the non-caulked portion of the small diameter tube portion 3 (distance from the end of the tube body 1 to the flat overlapping portion 5) is 1 mm.
However, these thickness and length may be arbitrary values, and by changing these values, the pressure at which the flat overlapping portion 5 begins to deform and the pressure at which the working fluid begins to leak can be changed as appropriate. .

Next, a second embodiment of the present invention will be described.

FIG. 3(a) is a plane showing the sealed part of a human vibrator as a second embodiment of the present invention. FIG. 3(b) is a plane showing the third embodiment of the human vibrator.
It is a sectional view taken along the line CC in Figure (a).

The heat pipe of the second embodiment (1 mm as shown in these drawings) is attached to the end of the tube body 11.
A small diameter cylindrical portion 13 with a long length of mm is formed, and a portion 1 with 1 mm left at both ends of the small diameter cylindrical portion 13:
A flat overlapping part 15 is formed, and the tip +3a of the small diameter cylindrical part 13 on the flat overlapping part 5 side (right side in the figure) is filled with a brazing material 17.
This is a brazed structure.

The heat pipe of the second embodiment constructed in this way (above, similar to the first embodiment, has excellent effects on safety and maintainability, and furthermore, since the part to be brazed with the brazing material) 7 is cylindrical. 1mm It also has the effect of making brazing work easier.

Next, a third embodiment of the present invention will be described.

FIG. 4(a) is a plan view showing a sealed portion of a heat pipe as a third embodiment of the present invention. FIG. 4(b) is a sectional view taken along the line DD of FIG. 4(a).

Heat Pipe of Third Embodiment] As shown in these drawings, a disk-shaped plug 22 is joined to the end 21a of the tube 21, and the inside of the tube 21 and the communication port 23 are connected to the plug 22. A small-diameter cylindrical portion 24 that communicates with the via is formed by patterning, and a flat overlapping portion 25 is formed on the small-diameter cylindrical portion 24 at a distance of 1 mm from the stopper in the same manner as in the first embodiment. (iii) The end portion 25a of the flat overlapping portion 25 is brazed with a brazing material 27.

As with the first embodiment, the heat pipe of the third embodiment constructed in this way has an excellent effect on maintainability.

Although several embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way.
For example, it is possible to implement the present invention in various ways without departing from the gist of the present invention, such as a structure in which the sealing part at the tip is sealed by welding such as TIG welding instead of being sealed by brazing. Of course.

[Effects of the Invention] As detailed above, the heat pipe of the present invention has
When the internal pressure of the heat pipe increases abnormally, the flat overlapping part deforms, so the abnormal pressure increase can be determined from the external appearance, and as a result, it is possible to prevent damage to people or property. , excellent safety. Moreover, even if the abnormal pressure rise continues and the flat overlying part is damaged, the working fluid will not leak out to the outside quickly, but will leak gradually over time, making it even safer. There is.

Furthermore, even if the user of the heat pipe misses the ejection of the working fluid, he or she can easily notice the failure of the heat pipe due to the expansion and deformation of the flat overlapping part, making it possible to minimize the disadvantages associated with malfunction. be.

[Brief explanation of drawings]

FIG. 1(a) is a plan view showing a sealed portion of a heat pipe as a first embodiment of the present invention. FIG. 1(b) is a sectional view taken along the line A-A of FIG. Figure (a) is the first
The plane of the sealed portion of the heat pipe showing the operation of the embodiment is shown in Fig. 2(b), and the cross section taken along line B-B in Fig. 2(a) is shown in Fig. 3(a), which shows the second embodiment of the present invention. FIG. 3(b) is a plan view showing the sealed portion of the heat pipe as a heat pipe according to a third embodiment of the present invention. FIG. FIG. 4(b) is a plane showing the sealed portion of the pipe, and FIG. Figure 5(b) is a flat plate showing the sealed portion of the heat pipe except for one.
It is an E-line sectional view. 1.21...Tube body 3.24...Small diameter cylindrical part 5.25...Flat overlapping part B 27...Brazing material 3...Communication port

Claims (1)

[Scope of Claims] A heat pipe closed by providing a small-diameter cylindrical portion at an end of the tube that communicates with the inside of the tube and whose other end is sealed, comprising: a communication port that communicates between the inside of the tube and the small-diameter cylindrical portion; The heat pipe is characterized in that at least a portion of the small-diameter cylindrical portion is pressurized so that the wall surfaces thereof overlap each other to form a thin flat overlapping portion.