JPH0227596B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pipe, and particularly to a heat pipe for transporting heat over long distances.

As is well known, heat pipes have a thermal conductivity that is tens to hundreds of times higher than that of copper, which has the highest thermal conductivity, so they can be used in heat exchangers, solar water heaters, and even medical equipment. It is used in various fields, and recently it has also been used for indirect cooling of power cables.

When a power cable is indirectly cooled by a heat pipe, the power cable generates heat over its entire length, so a considerably long heat pipe is required, and it is difficult to transport such a long heat pipe. In order to install or install the heat pipe, it is desirable to wrap the heat pipe around a drum, and it is also necessary to install the heat pipe at different heights to match the power cable. Therefore, it is desirable for a heat pipe for indirect cooling of power cables to have sufficient flexibility, as well as to have high capillary pressure and low pressure loss between the liquid-phase working fluid and the gas-phase working fluid. required.

However, as a flexible heat pipe, a heat pipe with a corrugated pipe as an exterior body has been known, but in such a heat pipe, the inner peripheral surface of the corrugated pipe is undulating, so Even when using a metal mesh, it is extremely difficult to bring the metal mesh into close contact with the inner circumferential surface of a corrugated pipe, and various problems arise in manufacturing. In order to solve this problem, it is possible to make the exterior body a straight metal tube with a certain degree of flexibility, but if the exterior body is simply made of a flexible metal tube, the heat pipe If it is bent, there is a risk that it may bend locally, and the pipe may become separated from the inner circumferential surface of the metal pipe, resulting in a narrowing of the flow path for the gas-phase working fluid or a constriction of the pipe. There is a problem in that the pressure loss of the liquid-phase working fluid increases due to

In addition, grooves, metal nets, porous sintered metal, etc. are known as conventional heat pipes, but conventional heat pipes using grooves have a low capillary pressure, and the heat can be kept for a long time. It is not suitable for indirect cooling of power cables that need to be transported over long distances. In addition, heat pipes made of metal mesh or porous sintered metal can obtain higher capillary pressure than the aforementioned heat pipes made of grooves, but on the other hand, metal mesh or porous sintered metal In solid metal, the fine pores that serve as return channels for liquid-phase working fluid are intricately curved and intertwined vertically and horizontally, so the pressure loss of liquid-phase working fluid is large, and furthermore, when porous sintered metal is used as a wick, However, the flexibility of the heat pipe as a whole is lost, and as a result, it is difficult to indirectly cool power cables using conventional heat pipes.

This invention was made in view of the above circumstances, and has sufficient flexibility, high capillary pressure, and low pressure loss of liquid-phase working fluid and gas-phase working fluid. The object of the present invention is to provide a heat pipe capable of transporting heat over long distances, such as for indirect cooling of cables, and even when there is a certain degree of height difference. In other words, the features of this invention are:
The exterior body is formed of a flexible tubular body, and a large number of ultra-thin wires that act as a wick are closely arranged on the inner peripheral surface of the tubular body, and a large number of The structure is such that a corrugated tube having a small hole is inserted and the corrugated tube presses the ultrafine wire against the inner peripheral surface of the tubular body.

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a partial cross-sectional view showing one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the - line in FIG. A large number of ultra-fine wires 3 that act as a wick are closely arranged along the axial direction of the tubular body 2 on the inner circumferential surface of the tube, and a corrugated tube 4 is inserted into the inner circumferential side of the ultra-fine wires 3. After the non-condensable gas in the tubular body 2 is evacuated, an appropriate working fluid is sealed in the tubular body 2.

The tubular body 2 is formed into a tubular shape by, for example, curving both sides of a metal tape in the same direction and welding the ends of the tape against each other, and has flexibility as a whole. Further, the ultrafine wire 3 is made of glass fiber, carbon fiber, etc. with a diameter of about 5 to 100 μm, and is flexible in itself, and there is space between each fiber in the longitudinal direction, that is, in the axial direction of the tubular body 2. A fine gap is formed along the line, and the gap serves as a reflux path for the liquid-phase working fluid and generates capillary pressure. Further, the corrugated tube 4 is used to press the ultrafine wire 3 against the inner circumferential surface of the tubular body 2, and is formed with a large number of small holes 5 that communicate the inner circumferential side and the outer circumferential side of the corrugated tube 4. . Therefore, the corrugated pipe 4 separates a flow path for the gas-phase working fluid and a flow path for the liquid-phase working fluid.

Therefore, in the heat pipe 1 configured as described above, since the tubular body 2, the ultrafine wire 3, and the corrugated tube 4 all have flexibility, the whole has flexibility, Therefore, even if the heat pipe 1 is quite long, it can be transported or installed by being wrapped around a drum, for example, and when it is bent to be wrapped around a drum, the corrugated pipe 4 can cover the entire length. Since the guide is curved in an arc, there is no possibility of local bending or constriction. In addition, in the heat pipe 1 described above, when a suitable part of the heat pipe 1 is heated and another suitable part is cooled, the working fluid evaporated in the heating part passes through the small hole 5 formed in the corrugated pipe 4 and the corrugated pipe 4 is heated. It reaches the inner periphery, flows through the inner periphery to the cooling section with low vapor pressure, radiates heat and condenses in the cooling section, and evaporates the working fluid in the heating section, creating capillary pressure. Through the gap between the lines 3 the liquid phase working fluid flows back towards the heating section. In this case, in the heat pipe 1 described above, the return path from the cooling section to the heating section is linear due to the ultrafine wire 3, so the pressure loss of the liquid-phase working fluid is reduced, and the ultrafine wire 3 Since the gap between the wires 3 is extremely narrow, the effective capillary radius is extremely small and the capillary pressure increases. Since the flow path of the liquid-phase working fluid is divided into the The liquid-phase working fluid flowing in the line 3 does not scatter, and therefore, in the heat pipe 1 described above, even when the distance between the heating section and the cooling section is long, the liquid-phase working fluid can be sufficiently refluxed. In other words, heat can be transported over a long distance, and even if the heating section is located at a certain high position, heat can be transported.

In other words, the heat pipe described above can transport heat over long distances, be curved during transportation or installation, and provide sufficient indirect cooling for power cables that must be installed at different heights. .

As is clear from the above description, according to the heat pipe of the present invention, the exterior body is formed of a flexible tubular body, and the ultra-fine wire that acts as a wick is closely arranged on the inner peripheral surface of the tubular body. Furthermore, a corrugated tube having a large number of small holes is inserted into the inner circumferential side of the ultra-fine wire, and the corrugated tube presses the ultra-fine wire against the inner circumferential surface of the tubular body. As the effective capillary radius becomes smaller, high capillary pressure can be obtained, and the flow path of the liquid-phase working fluid formed within the ultra-thin wire that acts as a wick is linear. In addition, since the liquid-phase working fluid flow path and the gas-phase working fluid flow path are separated by the corrugated pipe, the pressure loss of the liquid-phase working fluid and the gas-phase working fluid is small. Heat can be transported over long distances, and the exterior body, wick, and corrugated tube are flexible, and the corrugated tube acts as a guide to smoothly curve the entire structure, so it does not bend locally. The entire body can be curved smoothly without bending, and since the ultra-fine wire is held down by the corrugated tube, the ultra-fine wire will not separate from the inner peripheral surface of the tubular body when it is bent. It can be prevented. Therefore, overall, the heat pipe of the present invention allows indirect cooling of power cables to be performed satisfactorily.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the - line in FIG. 1...Heat pipe, 2...Tubular body, 3...Extremely fine wire, 4...Corrugated tube, 5...Small hole.

Claims (1)

[Claims] 1. A corrugated tube in which a large number of ultra-fine wires are closely arranged on the inner circumferential surface of a flexible tubular body along the axial direction of the tubular body, and has a large number of small holes,
A long heat pipe for heat transport, wherein the ultra-thin wire is inserted into the inner circumferential side of the tubular body so as to be pressed against the inner circumferential surface of the tubular body, and a working fluid is sealed in the tubular body.