JP2536770B2 - Manufacturing method of small heat pipe - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a heat pipe having a relatively small inner diameter, and more particularly to a method for enclosing an appropriate amount of working fluid.

2. Description of the Related Art As is well known in the art, a heat pipe encloses only a working fluid that evaporates and condenses water, etc., inside a container having a closed structure, and a wick that causes a capillary pressure for refluxing the working fluid in the container. When heat is applied to a part of the container provided inside, the working fluid evaporates in that part, the steam flows to the part with low temperature, then radiates heat and condenses, resulting in the operation of the liquid phase By returning the fluid to the location where evaporation has occurred by the wick, heat is transported as latent heat of the working fluid. Such a circulating flow of the working fluid is caused by completely exhausting the non-condensable gas which does not condense at the target operating temperature such as air from the inside of the container, and therefore, in the manufacturing process thereof, The non-condensable gas is exhausted together with the injection of the working fluid.

Traditionally, the injection of working fluid with the exhaust of non-condensable gas is
Mainly, the vacuum method or the heat-discharging method was used.
Here, the vacuum method is a method of decompressing the inside of the container with a vacuum pump, injecting a dissolved working fluid into the container, and then further depressurizing the inside of the container while heating the container to exhaust the non-condensable gas. . In addition, the heating-discharging method pre-fills the container with working fluid in excess of the amount enclosed.
And by heating the container with the container temporarily tightened, the inside of the container is filled with the working fluid vapor, and then the temporary tightening of the container is released to eject the working fluid vapor, thereby This is a method of exhausting non-condensable gas.

Problems to be Solved by the Invention However, in the vacuum method, it is difficult to completely exhaust the non-condensable gas only by vacuum suction from the inside of the container, so so-called flushing is performed together with vacuum suction. Therefore, in the case of a small heat pipe with a small inner diameter, there is a risk that the working fluid may blister during flushing and eject an excessive amount of working fluid. Therefore, there is a problem that it is difficult to inject the working fluid into the container due to the surface tension of the working fluid. In any case, when manufacturing a small heat pipe, the vacuum method has a workability. I had a bad problem.

On the other hand, the heat-expulsion method can be easily performed on a harmless working fluid such as water, but heats and evaporates the working fluid in the container, and the resulting working fluid vapor expels the non-condensable gas from the container. Since it is a method of discharging, a large pressure difference between the internal pressure of the container when heated and the atmosphere in which the container is open causes a large amount of working fluid to blow out all at once, and as a result, the amount of working fluid enclosed There was a problem that it became difficult to control.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method capable of discharging non-condensable gas while appropriately maintaining the amount of working fluid enclosed.

Means for Solving the Problems In order to achieve the above object, the method of the present invention discharges a non-condensable gas by the working fluid vapor while suppressing the pressure difference between the inside and the outside of the container to a small value. More specifically, the working fluid for evaporating and condensing to transport heat is preliminarily injected into the container provided with the liquid injection nozzle part, and the liquid injection nozzle part A gas chamber filled with an inert gas for the working fluid is connected while maintaining airtightness, the working fluid is evaporated by heating the container, and the gas pressure in the gas chamber is adjusted to the inside of the container. By maintaining the pressure slightly lower than the pressure, the non-condensable gas in the container is transferred into the gas chamber by the vapor of the working fluid, and then the liquid injection nozzle is sealed. Is the method.

Function In the method of the present invention, the working fluid in the liquid phase is initially injected into the container, and the non-condensable gas such as air is contained in the container. Connecting. The gas in the gas chamber is an inert gas for the working fluid, and there is no reaction between the two. The container is heated to vaporize the working fluid therein and to increase the pressure in the gas chamber to a pressure slightly below the container internal pressure. Therefore, even if the container has a small diameter, sudden boiling of the working fluid and blowing of the working fluid do not occur therein, and the non-condensable gas in the container is gradually pushed out into the gas chamber by the working fluid vapor. Then, after the non-condensable gas is expelled by the working fluid vapor for a predetermined period of time, the liquid injection nozzle is sealed to complete the exhaust of the non-condensable gas from the container and the filling of the working fluid.

EXAMPLES Next, the method of the present invention will be described with reference to the examples shown in the drawings.

FIG. 1 is a schematic view showing a situation in which a non-condensable gas is being exhausted from the inside of a container 1 by the method of the present invention. The container 1 has one end sealed and a thin pouring on the other end. A small-diameter pipe provided with a liquid nozzle 2,
A condensable working fluid 3, which evaporates at a target temperature, such as water, is injected into the container 1. The amount is
The amount is a little larger than the required amount determined by the volume of the container 1 and the operating temperature. The container 1 is installed so that the liquid injection nozzle 2 faces upward, and the gas chamber 5 is connected to the liquid injection nozzle 2 while maintaining an airtight state by an O-ring 4.
The gas chamber 5 is for storing a gas inert to the working fluid 3, for example, an argon gas, a helium gas, a nitrogen gas, or the like, and a valve 6
It is connected to the gas cylinder 7 via. A heater 8 for heating to increase the internal pressure is attached to the outer periphery of the gas chamber 5.

The working fluid 3 can be injected into the container 1 by inserting a small-diameter tube (not shown) into the liquid injection nozzle 2 and performing the small-diameter tube. After connecting the gas chamber 5 to 1 in an airtight state, the container 1 is heated to evaporate the working fluid 3 therein. In that case, the pressure inside the gas chamber 5 is set to, for example, 6 kg / cm ² G in advance, and when the container 1 uses water as the working fluid, a temperature corresponding to the vapor pressure pressure (for example, at 160 ° C. of 5.3 kg). Heat to kg / cm ² G). After heating in this way, the internal pressure of the gas chamber 5 is gradually lowered to heat the container 1 while maintaining the differential pressure between the two low so that the internal pressure of the gas chamber 5 becomes slightly lower than the internal pressure of the container 1. To continue. In this case, the gas pressure may be adjusted by heating the gas chamber 5 similarly to the container 1.

By maintaining the pressure between the container 1 and the gas chamber 5 as described above, rapid boiling or blowing of the working fluid 3 inside the container 1 is prevented, and the non-condensable gas inside the container 1 becomes the working fluid vapor. Is gradually moved to the gas chamber 5 side. The container 1 is continuously heated for a predetermined time, and the liquid injection nozzle 3 is sealed (pinch off) when the working fluid 3 is evaporated in an amount exceeding the required residual amount. In this state, the inside of the container 1 is filled with only the vapor of the working fluid 3, so that the non-condensable gas can be completely exhausted from the inside of the container 1.

EFFECTS OF THE INVENTION As described above, the method of the present invention is basically a heating-discharging method. However, the gas pressure in the gas chamber is different from the internal pressure of the container caused by heating the container and evaporating the working fluid. Therefore, the pressure difference between the inside and the outside of the container becomes small, and as a result, even if the container has a small diameter, the working fluid inside the container does not boil or blow out suddenly. Therefore, according to the method of the present invention, in addition to the ease of operation by the heating-discharging method and the reliable exhaust of the non-condensable gas, it is possible to reliably prevent abnormalities such as bumping of the working fluid that frequently occur when the container has a small diameter. The amount of working fluid enclosed can be adjusted accurately, and according to the invention as a whole, a small heat pipe can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a situation in which the method of the present invention is being carried out. 1 ... Container, 2 ... Injection nozzle, 3 ... Working fluid,
5 ... Gas chamber.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Shinichi Sugihara 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Cable Co., Ltd. (72) Koichi Masuko 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (72) Inventor Masahiko Ito 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Cable Co., Ltd.

Claims (1)

(57) [Claims] 1. A working fluid for vaporizing and condensing to transport heat is preliminarily injected into a container provided with a liquid injection nozzle, and the liquid is inert to the liquid injection nozzle. Gas chambers filled with various gases are connected while maintaining airtightness, the container is heated to evaporate the working fluid, and the gas pressure in the gas chamber is maintained at a pressure slightly lower than the internal pressure of the container. The non-condensable gas in the container is transferred into the gas chamber by the vapor of the working fluid, and then the liquid injection nozzle is sealed, and the method for manufacturing a small heat pipe.