JPS63129297A - Heat pipe - Google Patents

Abstract

PURPOSE:To provide a heat pipe which does not deteriorate in its heat transfer performance for a long period and is simple to manufacture and of low cost by providing at the condensing section a wick having the nature that it oxidizes hydrogen gas and converts it into water. CONSTITUTION:A heat pipe 1 consists of a container 2 which is made, for example, of cupro-nickel of Cu-Ni material and a uniform material wick 3 which is loaded on the inner face of the container 2 and has the nature to oxidize hydrogen gas to convert it into water. After the container 2 is loaded on to the container main body 4 by brazing pure copper mesh to the container main body 4 in the state of two-layer winding, this container main body 5 with a wick is subject to heating treatment in the air to oxidize the wick 3, and an end cap 6 is formed on the side of the evaporation section 1b, and an end cap 7 having a nozzle is formed by welding on the side of the condensation section 1c, then after pouring pure water into them, the nozzle opening is sealed to produce the heat pipe 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a heat pipe in which water is used as a working fluid and iron, copper, or the like, which reacts with water to generate hydrogen gas, is used as a container material.

In this specification, the term "iron" includes not only pure iron but also iron alloys such as stainless steel and carbon steel. Furthermore, the term "copper" includes copper alloys in addition to pure copper.

Prior Art and Its Problems For example, heat pipes in which water is sealed in an iron container are widely used because of the high strength of the container and the high performance of water as a working fluid. However, such a heat pipe has a problem in that iron and water react to generate hydrogen gas, which deteriorates the heat transfer performance of the heat pipe in a short period of time.

In other words, the generated hydrogen gas diffuses within the container wall in an atomic state, and some of it is released outside the container at a constant rate, but most of it gradually accumulates in the condensation area inside the container and occupies the condensation area. This prevents the condensation of steam and leads to deterioration of the heat transfer performance of the heat pipe. Furthermore, since this deterioration progresses and increases at an accelerated rate over time, the life of the heat pipe is rapidly shortened as the usage time increases. Furthermore, the outer surface of iron containers may be aluminized for the purpose of imparting corrosion resistance and vacuum brazing of aluminum fins with a brazing layer, but containers that have been subjected to such treatment may Hydrogen gas that has diffused inside the wall is blocked by the formed aluminized film and cannot exit the container.

Therefore, in order to prevent the generation of hydrogen gas as described above and the performance deterioration of heat vibrators due to the generation of hydrogen gas, the condensing part of the container was made of palladium, which has good hydrogen permeability. (See Publication No. 49064),
Alternatively, by inserting a palladium wire into the condensation part of the container (see Utility Model Publication No. 142/1982), hydrogen gas accumulated inside the heat vibrator can be discharged to the outside of the heat vib through the palladium. things are provided. However, in such a heat vibrator, the permeation and discharge of hydrogen gas cannot keep up with the increased generation of hydrogen gas when used at high temperatures, and it is not only impossible to completely prevent deterioration of heat transfer performance. However, there was a problem in that the manufacturing cost was high because expensive palladium was required.

Furthermore, in a heat vibrator (see Japanese Patent Application No. 60-95391), which is an invention already disclosed by the present applicant and in which a solid oxidizing agent is disposed in the condensing part to oxidize hydrogen gas and return it to water, heat transfer is possible. Although it is excellent in suppressing performance deterioration, it cannot be said that it is easy to manufacture because it requires modification to place the oxidizing agent inside the container, and the manufacturing cost is also high. be.

An object of the present invention is to provide a heat vibrator that solves the above-mentioned problems, does not cause deterioration of heat transfer performance over a long period of time, is simple to manufacture, and is inexpensive.

Means for Solving the Problems The heat vibrator according to the present invention uses water as the working fluid and uses a container material that reacts with water to generate hydrogen gas. It is characterized by a wick that oxidizes hydrogen gas and returns it to water.

In the above, iron such as carbon steel, stainless steel, or copper is used as the material for the container.

In the above, wicks that have the property of oxidizing hydrogen gas and returning it to water include, for example, wicks made of various metals that have been widely used in the past, oxidized in a predetermined manner, and wicks that have the ability to oxidize hydrogen gas and return it to water. A porous sintered body, other homogeneous wicks with hydrogen gas oxidation ability may be used, a cylindrical porous sintered body such as CuO whose inner surface is covered with a fine wire mesh, and other A composite wick with hydrogen gas oxidation capability may also be used.

These wicks may be disposed only in the condensing section of the heat vibrator, or may be disposed on the entire inner surface of the heat pipe including the condensing section.

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

Example 1 In FIGS. 1 and 2, the heat vibrator (1) is 7
A cupronickel split container (2) of 0% Cu-'30% Ni, and a homogeneous wick (2) that is attached to the inner surface of the container (2) and has the property of oxidizing hydrogen gas and returning it to water.
3), in which pure water (path shown) is sealed as a working fluid in a container (2), and it was manufactured as shown in Figure.

That is, the container (2) has an outer diameter of 25.4 mm.

A container body (4) consisting of a circular tube with an inner diameter of 23.4 mm and a length of 100'Oa++n is filled with #80 cut to the specified size.
After inserting a double-wound pure copper mesh into the container body (4) and attaching the double-wound mesh to the container body (4) by brazing it so that it contacts the entire inner surface of the container body (4), the wick is attached. Heat the container body (5) to 560°C
The wick (3) was oxidized by heat treatment in air for 10 hours. Next, an end cap (6) is welded to one end of the container body (5) with a wick that will be on the evaporation section (1b) side, and a nozzle attachment is welded to the other end of the container body (5) that will be on the condensation section (1c) side. The container (2) was formed by welding the end cap (7). After filling the container (2) with pure water using a known method, the nozzle mouth was sealed to complete the production of the heat pipe (1).

Example 2 In FIGS. 3 and 4, a heat pipe (11) is attached to the same container (2) as in Example 1 and to the inner surface of the container (2), and is used to oxidize hydrogen gas and return it to water. Example 1
Same as , pure water (path shown) is sealed.

This composite wick (13) connects the inner surface of a cylindrical CuO sintered body (13a) that contacts the entire inner surface of the container body (4) with a #150 stainless mesh cylinder (13b).
The cylinder (13b) is tightly covered with the outer surface of the container body (4), and both ends of the cylinder (13b) are brazed to the inner surface of the container body (4).

Note that an end cap (6) is attached to the end of the heat pipe (11) on the evaporation part (llb) side, and an end cap with a nozzle (7) is attached to the end of the heat pipe (11) on the condensation part (lie) side. is also the same as in Example 1.

Heat pipe (1) (11) of Example 1 or Example 2
During use, hydrogen gas generated by the reaction between water, which is a working fluid, and the container (2) is oxidized by the wicks (3) and (13), and is released into water by the next reaction.

Cu O+H2=Cu +H20 Next, a test conducted to evaluate the heat transfer performance of the heat pipe according to the present invention will be described.

First, the heat pipe (1) of Example 1 is prepared, and as shown in FIG. ) and a horizontal heating furnace (20) consisting of the same heat vibrator (1).
from the evaporation part (1b) side until the center of its length reaches the opening edge of the heater part (20a) of the heating furnace (20), and then insert it into the condensation part (
1c) side is the heater part (2) in the heating furnace (20).
The heat vibrator (1) was placed horizontally in a state where it was exposed to the external air of 0a). In this arrangement state, the heating furnace (20
), and heat insulation of the heat vibrator (1) corresponding to one half of the length from the opening edge of the heater part (20a) to the opening edge of the covering part (20b) in the heating furnace (20) is increased. The temperature TA ('C) of the point (A point) in part (1a) is 2
Heating was carried out for 2000 hours while maintaining the temperature at 40°C. And the same heat vibe after 2000 hours (
1) Temperature T at the center point (0 point) of the tip on the condensing part (lc) side
c ('C) and the difference between both temperatures (TA - Tc-24
0-Tc-ΔT+) was determined. After that, the heated heat vibrator (1) is naturally cooled in the above arrangement,
Tc (°C) when the temperature reached TA-50°C was measured, and the difference between the two temperatures (TA - Tc - 50 - Tc - ΔT2) was determined.

Next, the heat pipe (11) of Example 2 was prepared, and ΔT1 and ΔT2 were determined under the same conditions as above.

Finally, for comparison, although the wick is made of the same material and the same dimensions as in Example 1, it is not subjected to the oxidation heat treatment as in Example 1, and in other respects is substantially the same as in Example 1. A heat pipe with the same configuration was prepared, and ΔT and ΔT2 were determined under the same conditions as above.

Table 1 shows the results of heat transfer performance evaluation tests conducted using the three types of heat pipes described above.

Table 1 As is clear from Table 1, in the two products of the present invention equipped with a wick capable of oxidizing hydrogen gas and returning it to water, the insulation part and condensation part remained the same even after 2000 hours. The temperature difference between the two does not exceed 1°C, and the heat transfer performance is extremely good.

On the other hand, with the comparative product, which has a wick but does not have the property of oxidizing hydrogen gas and returning it to water, the above temperature difference is quite large and is transmitted in a short period of time. It can be seen that the thermal performance deteriorates.

Effects of the Invention According to the heat vibrator of the present invention, a wick having the property of oxidizing hydrogen gas and returning it to water is disposed at least in the condensing part, so that water, which is the working fluid, reacts with the container and generates hydrogen. Even if gas is generated, this hydrogen gas is oxidized by the wick and returns to water. Therefore, deterioration of the heat transfer performance of the heat vibrator due to the generated hydrogen gas can be suppressed.

In addition, a wick that has the property of oxidizing hydrogen gas and returning it to water can be formed relatively easily by oxidizing a conventionally widely used metal wick using a predetermined method. The vibrator can be manufactured more easily and at lower manufacturing cost than conventional ones that require special work to place the oxidizing agent inside the container.

Furthermore, unlike the conventional products described above, expensive materials such as palladium are not used, so according to the present invention, it is possible to provide a heat vibrator that is inexpensive to manufacture.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a first embodiment of the heat vibrator according to the present invention, FIG. 2 is a cross-sectional view of the heat vibrator shown in FIG. 1, and FIG. FIG. 4 is a cross-sectional view of the heat vibrator shown in FIG. 3, and FIG. 5 is a vertical cross-sectional view showing the method of the heat transfer performance evaluation test of the present invention. (1)(11)...Heat vibe, (2)...Container, (lc)'(ILc)...Condensing section, (3)(1
3)...Wick. that's all

Claims (1)

[Claims] In a heat pipe in which water is used as the working fluid and a container material that reacts with water to generate hydrogen gas is used, at least the condensing part has a wick that has the property of oxidizing hydrogen gas and returning it to water. A heat pipe characterized by being arranged.