JPS6045358B2 - Heat pipe and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sulfur heat pipe in which sulfur is vacuum sealed in a double pipe in which an aluminum or aluminum alloy pipe is fitted inside a steel pipe, and a method for manufacturing the same.

As is well known, a heat pipe is a system in which a condensable working substance is sealed in a sealed vacuum container, and the working substance is evaporated and condensed at different locations in the container, thereby performing heat propagation using the latent heat of the working substance. It is something that can be done.

Heat pipes are used for industrial heat recovery.

In particular, various materials have been reported for heat pipes used in the temperature range of 500 to 1000 degrees Celsius, but representative examples include pure nickel, nickel, cobalt, molybdenum-based alloys, and Sodium, potassium, lithium, etc. are used as working substances. In this way, expensive Ni, NiNCo, or Mo-based alloys are used as container constituent materials, and
Since the above-mentioned working substances are easily oxidized, sufficient care must be taken to prevent oxidation during the production of heat pipes, and they have disadvantages such as being troublesome to handle and causing problems with corrosion of containers and wood. . Therefore, a heat pipe was proposed in Japanese Patent Application Laid-Open No. 154151/1983 that overcomes these shortcomings and is capable of withstanding the above-mentioned operating temperature range, is easy to manufacture, and is inexpensive. The heat pipe described in the publication is "a steel pipe whose inner wall surface J is coated with aluminum ice and in which sulfur is vacuum-sealed as a working fluid." Although the proposed sulfur heat pipe exhibits excellent characteristics as a heat pipe for industrial heat recovery as described above, there are the following problems in the manufacturing method of the heat vibrator. (1) In order to improve sulfur corrosion resistance, the inner wall surface of the steel pipe is aluminized, so the sealing of the sealing nozzle is significantly affected by the presence of the Fe-A1 alloy layer between the iron and aluminum plating layers. Requires skill and care.

(2) In the case of a sulfur heat vibrator that has concave grooves (groups) in the longitudinal direction on the inner surface of a steel tube and an aluminized coating applied to the entire inside of the tube, it is difficult to perform group processing on the inner wall surface of the steel tube. At the same time, it becomes difficult to make the shape of the group appropriate when performing aluminization.

In view of the above-mentioned problems, the heat vibrator manufacturing method requires great care when using a tube with aluminized inner wall surface of the steel pipe, and has disadvantages in the manufacturing method such as poor productivity. The present invention has been devised for the purpose of providing a heat vibrator that improves the drawbacks of the heat vibrator proposed above in terms of its manufacturing method.

The present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a heat vibrator as a completed product.

In the figure, reference numeral 1 indicates a steel pipe, and an aluminum pipe 2 is fitted inside this pipe to form a sealed double-walled double pipe. Groups 3 are grooved at predetermined intervals in the longitudinal direction of the inner wall of the aluminum tube, a predetermined amount of sulfur 4 is sealed in the double tube, and steel caps 5 are provided at both ends of the steel vibrator.
is covered with the sealed side end of the aluminum vibrator.
A heat vibe is constructed by forming an air chamber 6 between them.
Number 7 in the figure indicates a nozzle pipe. The specific manufacturing method for this heat vibrator is to shrink-fit an aluminum vibrator inside a steel vibrator, fit it in by fitting a wiper tube, etc. to form a double tube, and then After machining groups with a predetermined depth and width at predetermined intervals on the inner wall surface of the vibrator, an end cap of the same quality is welded to one end of the vibrator, and a predetermined amount of sulfur (e.g. , 15±5% of the inner volume of the tube), then weld an end cap equipped with a suction nozzle tube to the other end of the vibrator, connect the suction nozzle tube to a vacuum system, and perform a predetermined After suctioning to a vacuum level, the nozzle pipe is sealed off at a position close to the end face of the cap, and the steel cap is fixed to both ends of the steel vibrator by screwing, brazing, etc. It will be done.

According to the heat vibrator and the manufacturing method thereof of the present invention, the following advantages will be exhibited.

[1] The outer steel vibrator has high temperature strength against the external environment, and the inner aluminum vibrator is used as the heat vibrator, so when enclosing sulfur,
Since the suction nozzle pipe can be sealed very easily, productivity is significantly improved.

■] Grooving of the inner wall surface of the aluminum vibrator is extremely easy, and the shape of the group can be maintained properly.

[■] In the aluminized steel described in JP-A-52-154151, Fe in the contact area between the steel and aluminum is
Although it is easy to diffuse in the -A1 alloy layer, in the case of the present invention, there is no fear of diffusion deterioration due to mechanical contact.

■] As for the contact thermal resistance of the contact surface between the steel vibrator and the aluminum vibrator, since a double tube can be manufactured at room temperature, the inner aluminum vibrator has a higher coefficient of thermal expansion at the temperature when the heat vibrator is used. There is no need to be seriously concerned.

However, a double tube with a steel vibrator on the inside and an aluminum vibrator on the outside is not preferable because the contact thermal resistance increases. ■] Since air exists in the gap between the aluminum vibrator and the steel caps that cover both ends of the aluminum vibrator, which is closed at both ends, air pressure increases considerably at the operating temperature, and this pressure acts to offset the pressure of the encapsulated sulfur,
Reduces the load on the aluminum vibrator.

Examples of the present invention will be shown below to clarify the effects. Steel pipe (STB35: outer diameter 25.47 m, wall thickness 1.67
m1 length 85Tmn), depth 0.2 on the inner wall surface.
Tn! n, width 1.0[
After fitting the expanded tube (wall thickness: 1.6 mm), a homogeneous end cap was welded to one end of the aluminum tube, and 15% of the internal volume of the aluminum tube was charged into the tube.

Next, attach an outer diameter of 3Wr to the other end of the tube. N1 inner diameter 2mm, length 3h with suction nozzle pipe? Welded aluminum end cap. Connect this nozzle tube to the vacuum system,
Vacuum degree 10-7? After suctioning up to Hg, the nozzle pipe is sealed and the outer diameter 37Wfi1 depth 35 is installed at both ends of the steel pipe.
A 7wt cap was screwed together to create an air layer between the end face and the steel vibrator tube. A performance evaluation test of the thus obtained heat vibrator was conducted.

As a comparative heat vibrator, a heat vibrator manufactured using the aluminized steel mentioned above and manufactured in the same manner as in this example was used. As shown in Figure 2, the evaluation test method involved applying heat insulating material A to one side of the heat vibrator over a length of 130 mm.
It was heated with a sheathed heater B covered with

The temperature distribution was measured by measuring the temperature at the location indicated by the number indicating the mounting position of the thermocouple in the same figure, and the measurement results are shown in FIG. 3 in correspondence with each other. In FIG. 2, the dimensions (unit: 7!n) of the mounting position of the thermocouple are marked. Further, since the symbols attached to the heat vibrator appear in the same way as the symbols in FIG. 1, explanations thereof will be omitted. As seen in the temperature distribution in FIG. 3, it can be seen that the heat vibrator of the present invention exhibits better performance than the comparative heat vibrator.

The above example shows a heat vibrator with groups grooved on the inner wall of the aluminum tube that makes up the double tube, but even if it is a heat vibrator with a normal wick or a thermosiphon without a group, Similar performance can be obtained.

Furthermore, when grooves are provided on the inner wall surface of the aluminum pipe, they may be provided in advance before constructing the double pipe, or may be provided after constructing the double pipe. To be determined as appropriate.

The gap between the air spaces formed by covering the steel cap is determined by taking into account the length of the sulfur-filled aluminum tube, but there is no need to limit it to exact dimensions. According to the present invention, it is possible to obtain a heat vibrator that satisfies the advantages described above and has excellent performance.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the heat vibrator of the present invention, FIG. 2 is an explanatory diagram showing the temperature distribution measurement position ζ of the heat vibrator of the present invention, and FIG. 3 is a graph showing the measurement results showing the temperature distribution. Explanation of symbols, 1...Steel vibrator, 2...Aluminum vibe, 3...Group, 4...Sulfur, 5...
...Steel cap, 6...Air chamber or air gap.

Claims (1)

[Claims] 1. An aluminum pipe is fitted inside a steel pipe, and sulfur is vacuum-sealed in a double tube with both ends of the aluminum pipe sealed, and both ends of the steel pipe are sealed. A heat pipe in which an air chamber is formed between the aluminum pipe and the side end surface of the aluminum pipe by covering the cap with a cap. 2 Fit an aluminum pipe inside the steel pipe, weld an end cap of the same quality to one end of the aluminum pipe, charge sulfur into the pipe, and then attach a nozzle pipe to the other end. After welding an end cap with a A heat pipe manufacturing method characterized by fixing the cap.