JPH038477B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for manufacturing a heat pipe, and in particular to a heat expulsion method for evacuation of non-condensable gas and injection of condensable fluid from the inside of a tube body for a heat pipe. The present invention relates to a method for manufacturing a heat pipe.

BACKGROUND ART As is well known, a heat pipe has a structure in which only a condensable fluid such as water is sealed inside a sealed tube as a working fluid, and heats one end of the tube while heating the other end. Setting up a temperature difference in the tube by cooling it, such that the working fluid evaporates at the heated end and its vapor flows to the cooled end, where the working fluid vapor condenses and liquefies. This transports heat as latent heat accompanying the phase change of the working fluid. Therefore, in a heat pipe, in order to smooth the evaporation and condensation of the working fluid and the flow of the working fluid vapor, the inside of the tube is filled with non-condensable material such as air that does not condense within the operating temperature range. It is necessary to exhaust gases almost completely. Therefore, conventionally,
Various methods are used to inject the working fluid, such as heating expulsion method, gas liquefaction method, vapor expulsion method,
Methods such as the vacuum pump method are known. Among these methods, the heating expulsion method involves injecting a condensable fluid as a working fluid into a heat pipe tube, heating the tube to evaporate the working fluid, and releasing the vapor together with air. This is a method of discharging non-condensable gases such as, for example, from the inside of the pipe body, and because of its good workability, it is a method that is preferred when using a non-toxic fluid such as water as the working fluid.

Problems to be Solved by the Invention However, when a non-condensable gas is exhausted from the inside of a pipe by the heating expulsion method, it is necessary to heat the working fluid inside the pipe to near its boiling point. Simply heating the bottom of the pipe may cause bumping, which is particularly noticeable when the inner diameter of the pipe is small. When the fluid is sealed, there is a problem that the working fluid leaks due to bumping and contaminates the working environment. Furthermore, as mentioned above, since the working fluid leaks due to bumping, there is a problem in that it is difficult to control the amount of the working fluid remaining in the tube.

This invention was made in view of the above circumstances, and aims to provide a method for exhausting non-condensable gas by heating and expelling without causing bumping phenomenon. be.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention has a method of putting a condensable fluid as a working fluid into a tube for a heat pipe whose one end is sealed, and exposing the tube to the outside. When manufacturing a heat pipe by heating the tube body to discharge non-condensable gas together with condensable fluid vapor and then sealing the tube body, use a tube body whose inner diameter at the open end is narrowed. ,
The tube is arranged vertically with the open end facing upward, and the condensable fluid is filled with the lower end of the tube as a non-heating section to a position above the non-heating section. This method is characterized in that the non-condensable gas inside the tube is exhausted together with the condensable fluid vapor by heating the portion of the tube above the non-heated portion.

Effect Therefore, in the method of the present invention, the upper part of the tube containing the condensable fluid is heated except for the unheated part at the lower end, and the condensable fluid inside the tube is heated. Since the vapor pressure at the condensable fluid is increased, evaporation of the condensable fluid occurs at its liquid level, and as a result there is less risk of overheating and associated bumping phenomena occurring within the condensable fluid. In addition, since the upper end (opening) of the tube body is constricted, even if a bumping phenomenon occurs, the liquid splashed by the bumping will adhere to the inner wall of the tube at the constricted open end and return to the inside of the tube. Therefore, leakage or scattering of the condensable fluid to the outside due to bumping can be effectively prevented. Furthermore, since the lower end of the tube is a non-heating part, if the amount of condensable fluid decreases to the non-heating part, evaporation of the condensable fluid will no longer occur, so the final condensable fluid The amount of liquid, that is, the amount of liquid to be sealed in the tube can be automatically set to a constant amount up to the non-heated part. Therefore, according to the method of the present invention, it is possible to effectively prevent the condensable fluid inside the tube from leaking or scattering to the outside due to bumping, and at the same time, it is possible to accurately control the amount of condensable fluid to be contained within the tube. It becomes possible to control the

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing a situation in which the method of the present invention is implemented, and a tube body 1 for a heat pipe has a sealed structure in which the inner diameter of one end is narrowed to form a nozzle 2. A non-toxic condensable fluid such as water or alcohol is placed inside the body 1 as a working fluid 3. In order to exhaust non-condensable gas such as air from the inside of the tube 1, first, the tube 1 filled with the working fluid 3 is oriented vertically so that the nozzle 2 is on the upper side. In this state, the upper part of the tubular body 1 is heated by the heater 4, and the lower end part is set as a non-heating part 5, so that that part is not heated by the heater 4. That is, the tubular body 1 is heated with a temperature difference set above and below so that the temperature is higher on the upper side. As a result, the working fluid 3
Evaporation occurs from the upper side, and the non-condensable gas inside the tube body 1 is exhausted by the vapor. In that case, since the working fluid 3 is heated from above, there is little risk of bumping occurring, and even if bumping occurs, the working fluid 3 will not be splashed to the outside by the nozzle 2 whose inner diameter is narrowed. Prevented. Furthermore, when the amount of working fluid 3 decreases to the non-heating portion 5 at the lower end, evaporation of the working fluid 3 no longer occurs, so the final amount of working fluid 3 is automatically maintained at a constant level up to the non-heating portion 5. Can be set.

FIG. 2 is a schematic diagram showing another implementation state of the present invention, and in this example, the temperature gradient is set so that the temperature is higher on the upper side, and the pipe body 1 is heated and the working fluid 3 is vaporized. Non-condensable gases are evacuated by Such heating can be achieved, for example, by configuring the heater 4 with a heating coil and increasing the number of turns of the coil on the upper side. In other words, the example shown in FIG. 2 is a method of heating by continuously changing the temperature difference between the top and bottom, and even in such a heating state, the working fluid 3
evaporates from the liquid surface, thereby preventing the occurrence of bumping.

Incidentally, in each of the above embodiments, the tube body 1 is set vertically for heating, but the present invention is not limited to the above embodiments, and in short, the tube body 1 is set to be placed vertically so that the nozzle 2 is on the upper side. It is only necessary to install the tubular body 1, and the tubular body 1 may be inclined.

Effects of the Invention As is clear from the above explanation, the method of the present invention has a heat pipe tube with one end sealed.
A heat pipe is manufactured by filling a condensable liquid as a working fluid, heating the tube from the outside, expelling non-condensable gas along with condensable fluid vapor, and then sealing the tube. , the tube body is arranged vertically with its open end facing upward, and the lower end of the tube body is used as a non-heating section, and the condensable fluid is filled to a position above the non-heating section; By heating the part of the tube above the unheated part, the non-condensable gas inside the tube is exhausted together with the condensable fluid vapor, so the working fluid inside the tube evaporates from the liquid surface side and the liquid phase is activated. There is less risk of overheating in the fluid and the accompanying bumping phenomenon, and since the pipe body has a narrowed inner diameter at the upper open end, even if bumping occurs, the working fluid will It is possible to prevent leakage and scattering to the outside, and since the lower end of the tube is not heated as a non-heating section, the amount of working fluid remaining inside the tube can be controlled by the height of the non-heating section. can do. As described above, according to the method of the present invention, it is possible to effectively prevent the condensable fluid inside the tube from leaking or scattering to the outside due to bumping, and at the same time, it is possible to reduce the amount of condensable fluid to be contained within the tube. It becomes possible to control accurately.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one example of the implementation situation of this invention, and FIG. 2 is a schematic diagram showing another example of the implementation situation of this invention. 1... Pipe body, 3... Working fluid.

Claims (1)

[Claims] 1. In a heat pipe tube with one end sealed,
A heat pipe is manufactured by filling a condensable liquid as a working fluid, heating the tube from the outside, expelling non-condensable gas along with condensable fluid vapor, and then sealing the tube. , Use a pipe whose opening end has a narrowed inner diameter, and arrange the pipe vertically so that the opening end is located on the upper side, and place the lower end of the pipe in a non-heating part. The liquid condensable fluid is poured to a position above the non-heating part, and the non-condensable gas inside the pipe is exhausted together with the condensable fluid vapor by heating the part of the pipe above the non-heating part. A method for manufacturing a heat pipe characterized by: