JPH0678872B2 - Heat pipe - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pipe in which water is used as a working fluid, and iron, copper, etc. that generate hydrogen gas by reacting with water are used as a material for a container. .

In this specification, the term "iron" includes pure iron and other iron alloys such as stainless steel and carbon steel. Further, the term “copper” includes copper alloy in addition to pure copper.

2. Description of the Related Art Conventional technology and its problems For example, heat pipes in which water is enclosed in an iron container are widely used because of the high strength of the container and the high performance as a working fluid of water. However, such a heat pipe has a problem that iron and water react with each other to generate hydrogen gas, which deteriorates the performance of the heat pipe in a short time. That is, the generated hydrogen gas diffuses inside the wall of the container in an atomic state and is partly discharged outside the container at a constant speed, but most of it gradually accumulates in the condensation part inside the container and occupies the condensation part. Therefore, it hinders the condensation of steam and deteriorates the heat transfer performance of the heat pipe. Moreover, this type of degradation increases proportionally with time, thus accelerating the life of the heat pipe. Further, the outer surface of the iron container may be subjected to aluminized treatment for the purpose of corrosion brazing and vacuum brazing of aluminum fins having a brazing layer.
In this case, the hydrogen gas diffused inside the wall of the container is blocked from being discharged to the outside of the container by the formed aluminized film.

Therefore, in order to prevent the generation of hydrogen gas as described above and the performance deterioration of the heat pipe due to the generation of hydrogen gas, the following methods have been conventionally used.

To suppress the reaction between water and iron by adding an inhibitor to water.

To plate the inner surface of the iron container with metal such as copper.

 Provide a hydrogen storage material in the container.

A linear hydrogen permeable member made of Pd may be provided so that the inside and the outside of the container may communicate with each other (see Japanese Utility Model Publication No. 56-142), and the condensing part may be formed of Pd having good hydrogen permeability (Actual development number 50). -49064 publication).

However, even with the above method, the generation of hydrogen gas could not be suppressed.

Further, in the case of the above method, the hydrogen gas occlusion or permeation and discharge did not catch up with the generation of hydrogen gas which further increases during use at high temperature. Therefore, even with the above methods, it was not possible to sufficiently suppress the performance deterioration of the heat pipe.

An object of the present invention is to solve the above problems and to provide a heat pipe which does not cause performance deterioration for a long period of time and is low in cost.

Means for Solving Problems A heat pipe according to the present invention is a heat pipe in which water is used as a working fluid and hydrogen gas is generated as a material of a container by reacting with water. A mesh for partitioning the inside of the container at a predetermined distance from the container end is provided in the condensing part, and a granular or powdery oxidizer for oxidizing hydrogen gas to return to water is provided between the mesh and the container end. It is characterized by being included.

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

In the above, as the oxidizer for oxidizing the hydrogen gas to return it to water, it is preferable to use an oxidizer that causes a reaction of H ₂ + MO → H ₂ O + M (M represents a metal element). Of these, C _U2 O and C _U O are used because they do not adversely affect the performance of the heat pipe when placed in the heat pipe, are cheap, and have excellent hydrogen gas oxidation effects. Is good. The amount of oxidant must be sufficient to oxidize the hydrogen generated in the heat pipe. For example, a 3 m long heat box filled with water in an iron container
In pipes, even if an anticorrosive film is formed on the inner surface of the container, a maximum of 2cc of hydrogen gas is generated per day. Therefore, if this heat pipe is to be used for 10 years, 30 g of C _{U 2} O (0.32 mol or more) should be placed in the container.

Effect According to the heat pipe of the present invention, the hydrogen gas generated by the reaction between water and the container is oxidized by the oxidant and returns to water, and is not accumulated in the condensing section in a gas state. Also, since the oxidizing agent is in the form of granules or powder,
Since the surface area is large, the reaction efficiency between hydrogen gas and the oxidizing agent is improved.

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

In Fig. 1, the heat pipe (1) is an STB35 long pipe (2a) and an ST welded to one end of the long pipe (2a).
A container body (2) made of B35 short pipe (2b),
Inside a container (5) consisting of an SS41 end cap (3) welded to one end of the container body (2) and an SS41 nozzle end cap (4) welded to the other end of the container body (2) Pure water (not shown) as a working fluid is sealed so as to fill 20% of the entire inner volume of the container (5). A copper mesh (6) is brazed with silver brazing to a portion of the short pipe (2b) near the long pipe (2a). Then, between the copper mesh (6) and the end cap (3), a granular oxidizer (7) composed of C _{U 2} O
Is included in 30g. The copper mesh (6) prevents the oxidizer (7) from moving to the long pipe (2a) side.

In this heat pipe (1), the short pipe (2b) side is used as a condensation section (8) and the opposite side is used as an evaporation section (9). Then, the hydrogen gas generated by the reaction between the working fluid, water, and the container (5) is oxidized by the oxidant (7) and causes the next reaction to return to water.

C _U O + H ₂ → C _U + H ₂ O Next, the tests conducted to evaluate the performance of the heat pipe according to the present invention will be described.

First, a STB35 long pipe (2a) with a diameter of 31.8 mm, a wall thickness of 4.5 mm, and a length of 2900 mm and a diameter of 31.8 mm, a wall thickness of 4.5 mm, and a length of 100 mm
The short pipes (2b) were prepared, and the inner surfaces of these pipes were brushed with a wire brush, and then degreased with an ascent. Then, # 80 copper mesh (6) was brazed into the short pipe (2b). Then, after the granular oxidizer (7) made of C _{U 2} O is put in the short pipe (2b), the end cap (3) is welded to one end of the short pipe (2b) and the short pipe (2b) The other end was welded to one end of the long pipe (2a). Then, the end cap (4) with a nozzle was welded to the other end of the long pipe (2a) to form a container (5). Then, pure water was sealed in the container (5) by a known method. Thus, the heat pipe (1) was manufactured.

Then, as shown in FIG. 2, the water cooling jacket (11) is put on the condenser part (8) side half of the heat pipe (1) and the electric heater wire ( 12) was wound and covered with a heat insulating material (13) from above. Then, the heat pipe was placed in a state of being tilted by 6 degrees with respect to the horizontal plane so that the end on the side of the condensing part (8) was on the upper side. In this state, while cooling water is supplied and circulated in the water cooling jacket (11) to cool half of the heat pipe (1), the other half is cooled by the electric heater wire (12).
20mm from the tip of the condensing part (8) while heating to 0 ℃ (P
The temperature of 1) and the temperature of the point (P2) at the center of the length outside the water cooling jacket (11) are measured every predetermined time, and the temperature difference (ΔT) between both points (P1) and (P2) Was measured. At this time,
The amount of heat transferred from the evaporation section (9) to the condensation section (8) is always 4000.
I set it to W. The results are shown in FIG.

For comparison, a heat pipe having substantially the same configuration as that of the above-mentioned example except that an oxidant was not placed in the condensing part was used, and its performance evaluation test was conducted under the same conditions as above. Was done. The results are shown in FIG.

As is clear from the graph shown in FIG. 3, the condensing part (8)
In the product of the present invention in which the oxidizer (7) was put inside, the temperature difference (ΔT) was about 3 ° C. even after 1000 hours, showing that the heat transfer performance was still good. On the other hand, in the comparative product, the temperature difference (ΔT) becomes considerably large, and it can be seen that the heat transfer performance deteriorates in a short time.

In the above embodiment, the case where the heat pipe of the present invention is applied to the heat pipe having no wick is shown, but it is also applicable to the heat pipe having the wick.

EFFECTS OF THE INVENTION According to the heat pipe of the present invention, since the oxidizing agent that oxidizes hydrogen gas and returns it to water is arranged in the condensing portion,
Even if hydrogen, which is a working liquid, reacts with the container to generate hydrogen gas, the hydrogen gas is oxidized by the oxidant and returns to water. Therefore, the deterioration of the heat pipe performance due to the generated hydrogen gas can be suppressed. further,
By disposing an oxidizing agent in an amount capable of oxidizing the total amount of hydrogen gas that is expected to be generated, it is possible to reliably suppress performance deterioration for a long period of time. In addition, even if the amount of hydrogen gas generated increases during use at high temperatures,
This can be quickly returned to water, and the performance deterioration of the heat pipe can be suppressed. Moreover, since the oxidizing agent is in the form of granules or powder, the surface area thereof is large, and the reaction efficiency between hydrogen gas and the oxidizing agent is improved. Therefore, the generated hydrogen gas can be quickly returned to water. Moreover, the mesh prevents the oxidant from moving from the condensing part.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a heat pipe according to the present invention with the middle part omitted and a part cut away, and FIG. 2 shows the first part.
The partially cut-away front view showing the method of the performance evaluation test of the heat pipe shown in the figure, and FIG. 3 are graphs showing the results of the performance evaluation test of the heat pipe shown in FIG. 1 together with the results of the comparative product. . (1) ... Heat pipe, (5) ... Container, (7) ...
Granular oxidizer, (8) ... Condensing part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuichi Furukawa 6224, Kaiyamacho, Sakai City, Osaka Prefecture Showa Alminium Co., Ltd. (72) Inventor Issei Noguchi 6224, Kaiyamacho, Sakai City, Osaka Showa Al Minium Co., Ltd. (56) Reference JP-A-61-41889 (JP, A) Actually developed Shou 62-29568 (JP, U)

Claims (1)

[Claims] 1. A heat pipe in which water is used as a working fluid and a material that reacts with water to generate hydrogen gas is used as a material of a container, in a condensing part of the container,
A mesh for partitioning the inside of the container is provided at a predetermined distance from the end of the container, and a granular or powder oxidizer for oxidizing hydrogen gas to return to water is placed between the mesh and the end of the container. A heat pipe characterized by that.