JPH03211394A - Manufacture of heat pipe - Google Patents

Abstract

PURPOSE:To enable a heat pipe deteriorated in performance to be easily regener ated, by inserting a hose into a pipe which is open at one end and closed at the other end, through the open end to a position near the closed end, and gradually drawing the hose out of the pipe while ejecting a gas from the tip of the hose into the pipe. CONSTITUTION:A hose 4 is inserted into a pipe which is open at one end and closed at the other end, via the open end to a position near the closed end. Next, the hose 4 is gradually drawn out of the pipe while ejecting a gas from the tip of the hose 4 into the pipe, whereby foreign matter is discharged from the pipe by the gas. After a cap 3 is attached to the open end of the pipe, the pipe is evacuated, and an appropriate working fluid is sealed in the pipe. Thereby, a heat pipe 1 can be regenerated securely and easily. The heat pipe 1, which has conventionally had to be replaced by a new one, can be continually used through regeneration, leading to an increase in the operating efficiency of an installation or apparatus using the heat pipe 1.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a method for manufacturing a heat pipe, and more particularly to a manufacturing method suitable for work at a heat pipe installation site.

Conventional technology The general structure of a heat pipe is that a condensable fluid such as water, fluorocarbon, or alcohol that evaporates and condenses within the operating temperature range is placed inside a sealed tube from which non-condensable gases such as air are completely exhausted. This is a structure in which a wick such as a wire mesh or narrow groove is provided inside a sealed tube to enclose liquid as a working fluid and cause the liquid-phase working fluid to circulate. And the heat pipe
By applying heat to one end and removing heat from the other end, the working fluid evaporates and the vapor flows to the other end, radiating heat and condensing, resulting in a liquid-phase working fluid. is returned to the heating section via the wick.

Such circulation of the working fluid accompanied by evaporation and condensation means that the working fluid vapor continues to flow into the cooling part due to the pressure drop due to condensation of the working fluid at the end where heat is transferred to the outside, that is, the cooling part, and the condensation occurs. The liquid-phase working fluid generated in this process continues to flow back to the heating section under the capillary pressure of the wick. Therefore, in heat pipes, it is necessary to sufficiently exhaust the non-condensable gas inside. Otherwise, the evaporation of the working fluid will be inhibited, and the non-condensable gas will be forced into the cooling part, causing cooling. with the section blocked,
That is, a state occurs in which the wall surface of the cooling section is shielded from the working fluid vapor, and heat transport by the working fluid is inhibited. In other words, the performance of the heat pipe is reduced or heat conduction is no longer performed.

Problems to be Solved by the Invention As mentioned above, in heat pipes, it is necessary to almost completely exhaust non-condensable gas, except in special cases. In addition, the materials for the pipe and working fluid should be selected so that they do not react with each other, and when sealing the working fluid, sufficient vacuum suction and heating should be used to heat and boil the working fluid in the open pipe. The working fluid is filled in using the expulsion method, or flushing is performed by repeatedly introducing a small amount of working fluid and heating and vaporizing it, and the nozzle used to inject the working fluid is crushed and then welded to make it airtight. is doing various work. However, as is clear from its use or function, heat pipes are repeatedly heated and cooled, and their performance deteriorates over time because they are in a high vacuum state when they are cooled and, conversely, they are in a high pressure state when they are heated. Sometimes. In other words, for example, in a heat pipe in which water is sealed as a working fluid inside a steel pipe, hydrogen gas is generated, and if a thin-walled pipe is used to improve heat conduction and reduce heat capacity, pinholes may occur. This causes a decrease in airtightness and the intrusion of non-condensable gases, and furthermore, the precipitation of residual impurities, the reaction between the working fluid and the pipe material, or the generation of foreign matter due to the decomposition of either of these. evaporation and condensation of the working fluid may be inhibited, and as a result, the heat transport ability of the heat pipe may be reduced.

When a heat pipe is in such a so-called defective state, it is necessary to open the pipe and completely replace the gas and fluid inside, but in the past, there was no easy way to do this, so the heat pipe that was already installed was If it becomes defective, it has to be replaced with a new one, which has the problem of requiring a long construction period and increasing the cost.

The present invention was made against the background of the above-mentioned circumstances, and an object thereof is to provide a method by which a heat pipe whose performance has deteriorated can be easily regenerated.

Means for Solving the Problems In order to achieve the above object, the method of the present invention involves inserting a hose into a pipe whose one end is open and whose other end is closed, from the open end to near the closed end. The hose is gradually pulled out from inside the pipe while squirting gas into the pipe from the tip of the hose, and the gas is used to remove foreign matter.Then, after attaching a cap to the open end of the pipe, the inside of the pipe is removed. This method is characterized by performing vacuum degassing and further sealing an appropriate working fluid in the pipe.

Further, in the method of the present invention, the hose may have a double pipe structure of an inner tube and an outer tube, and the gas may be ejected from either the inner tube or the outer tube and sucked from the other.

Operation In the method of the invention, a hose is used to drain foreign objects or existing working fluid from the interior of a pipe, and for this purpose one end of the pipe is first opened.

In this case, if an existing heat pipe is used, as one end of the heat pipe is opened, outside air is rapidly absorbed or working fluid is ejected. A hose is inserted into the open end of the pipe, its tip is brought close to the closed end of the pipe, and in this state, the hose is gradually removed from the pipe while blowing out gas from the tip of the hose. Therefore, since new gas is supplied to the innermost part of the pipe, foreign matter and existing working fluid within the pipe are expelled to the open end side of the pipe. In that case, if a hose with a double pipe structure is used, and the gas is ejected from one of the inner or outer pipe and sucked from the other, the foreign matter can be discharged more reliably or quickly. After removing foreign matter, etc., a cap is attached to the open end of the pipe, from which the gas is vacuum-suctioned and new working fluid is injected.Finally, an opening for vacuum suction and new working fluid injection is opened. Close it and use it as a heat pipe. Therefore, with this method, the gas replacement work that also serves as cleaning inside the pipe becomes easy, so it becomes possible to perform the work at the installation site.

EXAMPLES Next, the method of the present invention will be explained in detail based on examples.

When a heat pipe 1 with an abnormality such as a decrease in heat transport capacity is found, one end of the pipe (hereinafter referred to as a container) 2 is cut off (FIG. 1).

In that case, if the temperature of heat pipe 1 is low,
Since the internal pressure is a vacuum pressure, outside air is sucked in. Further, since the cut end portion is attached with a cap 3 to make it airtight as described later, it is preferable to perform a finishing process to adjust the shape. Next, the hose 4 is inserted from the open end of the container 2, and its tip is brought close to the closed end of the container 2, as shown in FIG. Here, the hose 4 has a double tube structure consisting of an inner tube 5 and an outer tube 6. The inner tube 5 is connected to a gas supply source (not shown), and the outer tube 6 is connected to a suction source (not shown) such as a vacuum pump. It is connected. Further, a plurality of suction ports 61 are formed in the outer circumferential wall of the distal end of the outer tube 6. Therefore, gas is directly supplied to the innermost part of the closed end of the container 2, so the pressure in this part increases, and the remaining working fluid and foreign matter in the container 2 are pushed out from the innermost part to the open end. It will be done. Also, by suctioning from the outer tube 6, these working fluids and foreign substances to be discharged are sucked into the outer tube 6 from the tip of the outer tube 6 and the suction port 6, and are then discharged through the outer tube 6. It is discharged to a designated location. The gas used for such discharge work is preferably one that does not react with the container 2 and does not condense and remain as a liquid inside the container 2. Specifically, it is preferable to use N2 gas. can. Then, by gradually pulling out the hose 4 from the container 2 while blowing out the gas (as shown in FIG. 3), the gas is discharged over the entire length of the container 2.

After cleaning the inside of the container 2 as described above, as shown in FIG. The gas is vacuum-suctioned from inside the container 2 and exhausted. After that, apply the appropriate working fluid to the nozzle 7.
from the inside of the container 2 (Fig. 5). Note that these vacuum suction and injection of the working fluid may be performed multiple times with flushing, or may be performed in the same manner as conventionally known working fluid filling methods, such as using a heating expulsion method. After the vacuum degassing of the gas supplied from the hose 4 and the injection of new working fluid are completed, the nozzle 7 is crushed as shown in FIG. 6, and its open end is sealed by welding. In order to prevent the nozzle sealed in this manner from being damaged, an appropriate cover cap (not shown) may be attached.

Therefore, according to the above method, residual working fluid and foreign matter are sent from the closed end side to the open end side, so even if the container 2 has a small diameter or is long, it can be reliably and easily. The inside of the container 2 can be kept clean.

In addition, since the above method only requires opening one end of the container 2, it can also be applied to the installed heat pipe 1. Therefore, the above method does not require replacing the installed heat pipe 1. This is effective when playing this without

In the embodiments described above, the case where a hose 4 having a double-pipe structure is used is used as an example, but the present invention is not limited to the above-mentioned embodiments, and even if a single-pipe hose is used. good. Further, although the description has been made for a heat pipe without a wick, the method of the present invention can also be applied to a heat pipe provided with a wick such as a wire mesh, in the same manner as in the above embodiments. Furthermore, when using a hose with a double tube structure, contrary to the case shown in the above embodiment, gas may be ejected from the outer tube and sucked from the inner tube.

Effects of the Invention As is clear from the above explanation, according to the method of the present invention, gas and foreign matter inside the container are sent out to the open end side by blowing out gas from the hose inserted from one open end of the container. Even if a small-diameter container or a long container is used, and even if it is installed and cannot be changed in its position, or only one side can be opened, it is possible to regenerate heat pipes reliably and in a continuous manner. can. Therefore, according to the method of the present invention, it is possible to regenerate and continue using the lid heat pipe, which conventionally had to be replaced with a new one, increasing the operating rate of equipment using heat pipes, and making it possible to regenerate the heat pipe. Effects such as being able to reduce the cost required for this can be obtained.

[Brief explanation of drawings]

1 to 6 are schematic cross-sectional views for explaining the process of manufacturing a human pipe according to the method of the present invention. 1... Heat pipe, 2... Container, 3
...Cap, 4...Hose, 5...Inner pipe,
6...Outer tube.

Claims (2)

[Claims] (1) Insert a hose into a pipe with one end open and the other end sealed, from the open end to near the closed end, and insert the hose into the pipe while blowing gas from the tip of the hose into the pipe. The pipe is gradually pulled out to remove foreign matter using the gas, and then a cap is attached to the open end of the pipe, and the inside of the pipe is vacuum degassed.
A method for manufacturing a heat pipe, further comprising sealing an appropriate working fluid inside the pipe. (2) The hose has a double pipe structure of an inner pipe and an outer pipe, and the gas is ejected from either the inner pipe or the outer pipe,
A method for manufacturing a heat pipe, characterized in that the heat pipe is sucked from the other side.