JPS5854358B2 - How to make a heat pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a heat pipe as a heat exchanger, characterized in that a working fluid is sealed in a container of the heat pipe using a novel method.

In the conventional manufacturing of heat pipes, the method of sealing a working fluid such as water, alcohol, or mercury in the container is generally as illustrated in FIG.

In FIG. 1, 1 is a heat pipe container, 2 is an exhaust pipe, 3 is a distiller connected to the heat pipe container 1 and the exhaust pump, and 5 is a heater for heating the distiller 3 from the outside.

First, the exhaust pump 2 is operated to exhaust the air inside the heat pipe container, and then the working fluid 4 in the distiller 3 is heated and evaporated by the heater 5, and then introduced into the heat pipe container 1. When the required amount of working fluid 4 has been condensed inside and has been introduced into the container 1, the opening of the container is opened at A-A.
It is cut and sealed at the end.

However, in the conventional method described above, the vapor of the working fluid adheres to the piping or moves to the exhaust pump side during the process of distillation and purification of the working fluid, resulting in large losses, and it is difficult to control the amount of the working fluid sealed. Furthermore, it is difficult to manufacture high-performance heat pipes with uniform operating characteristics because the air is insufficiently expelled.

Additionally, since this method involves evaporating and condensing the working fluid and injecting it into the container, the injection time is long, and therefore it is not suitable for manufacturing large or long heat pipes that require a large amount of working fluid. .

Furthermore, as a very simple method, when the working fluid is water, for example, as shown in FIG.
There is a method in which the working fluid is heated to evaporate, the air inside the container 1 is expelled by the vapor, and then the opening of the container 10 is cut and sealed at the A-A section.

Furthermore, as the simplest method, there is a method in which a working fluid is injected into the heat pipe container in advance and the air inside the container is vacuum-exhausted using an exhaust pump.

Although these simple methods require less time to enclose the working fluid, they have the same drawbacks as the method shown in FIG. 1 above.

The present invention was made in view of the shortcomings of the conventional method of enclosing a working fluid in the manufacture of heat pipes, and uses an enclosing method that allows easy injection of the working fluid and reliably controls the amount of the enclosing fluid. The purpose is to provide a new method for manufacturing a heat pipe.

The basic feature of the invention is that an appropriate amount of pre-purified working fluid is injected into a heat pipe container, then the container is cooled by a refrigerant to solidify the working fluid, and then all the air in the container is evacuated. Afterwards, the container is sealed.

According to the above configuration, since the working fluid injected into the heat pipe container is cooled and solidified, the amount of evaporation when all the air in the container is exhausted can be almost ignored.

Therefore, a desired amount of working fluid can be accurately injected into the container.

In particular, it becomes easier to inject a low boiling point working fluid with a high saturated vapor pressure at room temperature into the container.

However, in the above configuration, if the melting point of the working fluid is very low, while the working fluid in the heat pipe container is being cooled by the refrigerant, components in the air may liquefy and be contained in the working fluid, or a chemical reaction may occur. There is a risk of causing

Therefore, a further feature of the invention is that in the above arrangement, the air in the heat pipe container is replaced with an inert gas after or before injecting the working fluid into the heat pipe container.

The inert gas is unlikely to dissolve or cause a chemical reaction with the working fluid, so there is no room for impurities to enter the previously purified working fluid, and as a result, a heat pipe with excellent operating characteristics can be obtained.

Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

FIG. 3 illustrates the basics of an embodiment of the invention.

In FIG. 3, 10 is a heat pipe container, 11 is a cooler for cooling the lower part of the container 10 from the outside with a refrigerant, 1
2 is an exhaust pump.

The narrow opening 14 at the top of the container 10 is connected to the exhaust pump 12.
It is sealed and introduced into a connecting jig 13 at the tip of a conduit 15 leading to the pipe.

In the above device, the working fluid 16 is purified in advance and then injected into the container 10 in a fixed amount.

Next, the cooler 11 is filled with refrigerant 11 .

The refrigerant 17 is for solidifying the working fluid 16,
Any substance may be used as long as it has a temperature lower than the freezing point of the working fluid.

If the working fluid is water, for example, a mixture of dry ice and acetone is suitable.

The working fluid 16 in the container 10 is cooled and solidified by the coolant 17 over a certain period of time, and the solidified working fluid is further brought to a sufficiently low temperature.

Next, the exhaust pump 12 is operated to evacuate the air inside the container 10.

The working fluid 16 within the air 10 is cooled and solidified, and has a very low saturated vapor pressure.

As is well known, the saturated vapor pressure decreases as the temperature of the working fluid decreases.

For example, in the case of water, at 20°C it is 17.5), -60
At °C (ice) it changes to 8.1 x 10-3 torr and at -100 °C 9.7 g/cltsec
), 1,4×10' (f/cyltsec), 1.
8X10-7 (f/cyst sec).

Therefore, if the upper half of the working fluid is cooled and solidified to a low temperature as described above, the amount of evaporation of the working fluid when deaerating the air in the container 10 will be almost negligible, and the amount of working fluid will not be reduced. , a sufficient vacuum state can be obtained within the container 10.

After deaerating the air in the container 10, the opening 14 of the container 10 is
- By cutting and sealing at part A, the heat pipe can be completed.

FIG. 4 illustrates an embodiment of the present invention based on the basic configuration shown in FIG.

In FIG. 4, the same reference numerals as in FIG. 3 indicate the same members.

In this embodiment, an inert gas cylinder 18 is installed, and the cylinder 18 and the inside of the heat pipe 10 are connected to a conduit 19.
It is connected with

That is, the conduit 19 is inserted into the connection jig 13 in a sealed manner, and its tip end is inserted into the mouth 14 of the container 100.

In this embodiment, a pre-purified quantity of working fluid 16 is injected into the heat pipe container 10, and an inert gas is introduced into the container 10 through a cylinder 18.

The air inside the container 10 is expelled from the gap between the pipe line 19 and the mouth part 14 of the container by the introduced inert gas, passes through the connecting jig 13 and the pipe line 15, and enters the league valve provided in the pipe line 15. 20 to the outside.

After all the air in the container 10 has been completely replaced with inert gas, the refrigerant 17 is filled into the cooler 11.

The purpose of replacing the inert gas with the air in the container 10 is to prevent components in the air from liquefying, dissolving, or reacting in the working fluid during cooling of the working fluid.

Therefore, when the working fluid 16 is cooled and solidified by the refrigerant 17, the inert gas must not be liquefied.In other words, the inert gas must have a boiling point lower than that of the refrigerant.

For example, when liquid nitrogen (boiling point -196°C) is used as the refrigerant, helium gas (boiling point -268.9°C) is used as the inert gas.

After the working fluid 16 is cooled and solidified by the refrigerant 17 and further cooled to a low temperature, the pipe 19 is connected to the connecting jig 1 at its tip.
3, and cut it at the B-B section near the connection jig 13 to seal it.

Thereafter, the exhaust pump 12 is operated to exhaust the inert gas inside the container 10 and make the inside of the container 10 a high vacuum.

During this deaeration, the amount of evaporation of the solidified working medium is almost negligible, as explained in the basic invention above.

After making the inside of the container 10 a high vacuum, the opening of the container is cut at the A-A section and sealed, thereby completing one heat pipe.

In the above embodiment, the working fluid 16 is injected into the container 1 in advance, but in another embodiment, the working fluid is injected into the container 1 after all the air in the container 1 has been replaced with an inert gas. It may be injected within 10 minutes.

As described above, in addition to the effects of the above-mentioned basic configuration, the present invention, of course, replaces the air in the container with an inert gas. Since it is possible to prevent the heat pipe from liquefying and dissolving, it is possible to accurately manufacture heat pipes that can be used with various working fluids and have good operating characteristics.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams showing a conventional heat pipe manufacturing method, respectively, and FIGS. 3 and 4 are explanatory diagrams of a heat pipe manufacturing method according to the present invention. 10... Heat pipe container, 11...
Cooler, 12...Exhaust pump, 13...
・Connection jig, 14... Mouth of container 10, 15・
... Pipe line, 16 ... Working fluid, 17 ...
... Refrigerant, 18 ... Inert gas cylinder, 1
9... Conduit, 20... League valve.

Claims (1)

[Claims] 1. Injecting an appropriate amount of previously purified working fluid into a heat-vibe container, then also before replacing all the air in said container with an inert gas having a lower boiling point than the refrigerant, and then
A method for manufacturing a heat pipe, characterized in that the container is cooled by the refrigerant to solidify the working fluid, and then all the inert gas in the container is evacuated, and then the container is sealed.