JPH0463316B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a heat pipe, which has excellent heat transport ability when transporting heat over a relatively long distance or when the heating part is slightly higher than the cooling part. This relates to a heat pipe that is effective when the following is required.

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

Heat pipes used in various fields have different lengths depending on their purpose.
In some cases, properties such as flexibility and the ability to transport heat even if there is a certain level difference are required. Even when these mutually different characteristics are required, it is necessary not to impair heat transport ability, but for example, with conventional heat pipes using grooves (groups), the capillary pressure obtained is low and In addition, since the grooves as the wicks are along the axial direction of the heat pipe, it is difficult to sufficiently spread the liquid phase working liquid over the entire inner circumferential surface. Pipes have a relatively low heat transport capacity, making it difficult to transport heat over long distances. In addition, heat pipes using metal mesh or porous sintered metal as the wick have been known, but such heat pipes have a higher capillary pressure than the aforementioned heat pipes that use grooves as the wick. The liquid phase working liquid can be distributed over the entire inner peripheral surface to a certain extent. However, on the other hand, in metal nets and porous sintered metals, the micropores that serve as return paths for the liquid-phase working liquid are intricately curved and intertwined vertically and horizontally, resulting in a large pressure loss for the liquid-phase working liquid. When sintered metal was used as the heat pipe, there was a problem that the heat pipe as a whole lacked flexibility.

Therefore, the present applicant has made the ultra-fine wires by arranging a large number of ultra-fine wires with diameters of about 5 to 100 μm along the axial direction of the sealed tube on the inner circumferential surface of the sealed tube that forms the exterior body. We have already proposed a heat pipe (Special Publication No. 61-41398). With a heat pipe configured like this, not only can the obtained capillary pressure be high, but the return path for the liquid-phase working fluid is linear and the pressure loss is small, so the return flow of the liquid-phase working fluid to the heating section is low. can be promoted to sufficiently increase the heat transport ability, and since the ultrafine wire itself has flexibility, it is also possible to make a flexible heat pipe. However, in the case of a wick constructed of ultra-fine wires, the gaps between the ultra-fine wires serve as return paths for the liquid-phase working fluid, so it is not possible to integrate the ultra-fine wires with adhesive, for example. When attaching the ultra-fine wire to the inner circumferential surface of the sealed tube forming the exterior body, conventionally, one ultra-fine wire is
One or more tubes were inserted into the sealed tube and placed in close contact with the inner circumferential surface of the tube, but this operation was very troublesome and took a long time. In addition, the ultra-fine wire attached to the inner circumferential surface of the sealed tube as described above is pressed and fixed in the radial direction against the inner circumferential surface of the sealed tube by an appropriate holding device inserted into the inner circumferential side. For example, JP-A-55-
The heat pipe shown in No. 68589 is fixed by pressure by inserting a spiral-shaped retainer inside, but the fixing force in the circumferential direction does not actively act, so it is difficult to prevent vibrations or other causes. When an external force is applied, the ultra-fine wire shifts in the circumferential direction of the sealed tube, impairing the uniformity of the ultra-fine wire in each part, and as a result, the reflux of the liquid-phase working fluid is inhibited, resulting in a reduction in heat transport capacity. It was hot.

Purpose of the Invention The present invention has been made in view of the above circumstances, and it is possible to easily and uniformly attach the ultra-fine wire constituting the wick to the inner circumferential surface of the sealed tube forming the exterior body, and the ultra-fine wire It is an object of the present invention to provide a heat pipe which has an excellent heat transport ability, which does not shift, has a high capillary pressure, and has a small pressure loss of a liquid-phase working fluid.

Structure of the Invention In other words, the present invention adds a wick that generates capillary pressure to the inner circumferential surface of a sealed tube, and
In the heat pipe in which a working fluid is sealed in the sealed tube, the wick moves a large number of longitudinally extending ultra-fine wire bundles along the axial direction of the sealed tube, and crosses the ultra-fine wire bundles and runs along the axial direction of the sealed tube. It has an integrated structure knitted with weft yarns arranged at regular intervals in the direction, and the volume ratio of the weft yarns to the longitudinally extending ultra-fine wire bundle is set to 0.1 or less, and the weft yarns are arranged on the inner circumferential side. It is characterized in that it is brought into close contact with the inner circumferential surface of the sealed tube by a presser inserted into the tube.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a partial sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view taken along the - line in FIG.
In this method, a wick 4 made of a large number of ultra-thin wire bundles 3 is placed on the inner circumferential surface of a sealed tube 2 forming an exterior body, and the wick 4 is further held by a presser 5 inserted into the inner circumferential side of the sealed tube 2. It is configured such that it is brought into close contact with the inner peripheral surface, and after a non-condensable gas such as air is sucked out from the inside of the sealed tube 2, an appropriate working fluid is sealed.

That is, the ultrafine wire bundle 3 has a diameter of 5 to 100μ.
It has a structure in which a large number of filament bodies such as carbon fibers and glass fibers with a diameter of about It is said that Further, the presser tool 5 is, for example, a metal band-shaped material curved into a spiral shape, and is formed so that its diameter expands due to elastic force. Therefore, the wick 4 knits an ultra-fine wire bundle 3 with weft threads 6, rolls the ultra-fine wire bundle 3 from a sheet state into a cylindrical shape so as to face the axial direction, inserts it into the sealed tube 2, and further reduces the diameter by applying elasticity. By inserting the deformed presser 5 into the inner circumferential side of the wick 4, the wick 4 is brought into close contact with the inner circumferential surface of the sealed tube 2 by the elastic force of the presser 5.

In the heat pipe 1 configured as described above, the gaps formed inside the ultra-fine wire bundles 3 and between the ultra-fine wire bundles 3 serve as reflux paths for the liquid-phase working fluid.
The ultra-thin wire bundle 3 is arranged along the axial direction of the sealed tube 2, and usually one end of the sealed tube 2 is used as a heating section and the other end is used as a cooling section, so that the liquid phase working fluid does not flow through the reflux path. The heat pipe becomes a linear flow path along the direction in which the flow should originally occur, and therefore a heat pipe with low flow resistance to the liquid-phase working fluid. Furthermore, since the gaps between the filament bodies constituting the ultrafine wire bundle 3 are extremely narrow, the effective capillary radius becomes small, that is, high capillary pressure can be obtained.

Note that it is preferable that the weft thread 6 is usually made of the same material as the ultrafine wire bundle 3. Further, the weft threads 6 are arranged at regular intervals along the axial direction of the sealed tube 2. Here, since the weft thread 6 intersects with the ultrafine wire bundle 3, it acts to inhibit the reflux of the liquid phase working fluid. Accordingly, the present inventors conducted experiments and found that it is preferable that the volume ratio of the weft yarn 6 to the ultrafine wire bundle 3 is 0.1 or less. In other words, the heating section was made slightly higher (slanted The heat pipe was operated in the so-called top heat mode (angle 5°), and the temperature distribution at each point of each heat pipe was measured. The results are shown in Figure 4, and the heat pipe with a volume ratio of 1 (curve A)
It was found that both the heat pipe and the heat pipe using a metal mesh (curve B) had a large temperature gradient, whereas the heat pipe 1 of the present invention (curve C) had an extremely small temperature gradient. In other words, it is known that if the liquid-phase working fluid flows back to the heating section sufficiently, the temperature inside the heat pipe becomes equal.
From the above results, the volume ratio of the ultrafine wire bundle 3 and the weft thread 6 can be determined.
It was found that when the value is 0.1 or less, sufficient reflux of the liquid-phase working fluid to the heating section occurs, resulting in excellent heat transport ability.

On the other hand, in the heat pipe 1 having the above-described configuration, the movement of the ultra-fine wire bundle 3 constituting the wick 4 in the circumferential direction is regulated by the weft thread 6, so that the ultra-fine wire bundle 3 is not displaced and the uniformity is impaired. Therefore, it is possible to keep the capillary pressure high and the pressure loss in the reflux path small for a long period of time.

In addition to the threaded strip material, various other materials such as a metal net or a metal wire rolled into an annular shape may be used as the presser.

Effects of the Invention As is clear from the above description, according to the heat pipe of the present invention, the heat pipe is made by knitting together a large number of longitudinally extending ultra-fine wire bundles along the axial direction of the closed tube with weft threads crossing the ultra-fine wire bundles. Furthermore, since the wick is in close contact with the inner circumferential surface of the sealed tube by a presser inserted into the inner circumferential side, the effective capillary tube is reduced due to the use of ultra-thin wire. Since the radius is small, high capillary pressure can be obtained, and the flow path of the liquid-phase working fluid formed within the longitudinally running ultrafine wire bundles and between the longitudinally running ultrafine wire bundles, which acts as a wick, is aligned with the axis of the sealed tube. It has a straight line shape along the direction, and the volume ratio of the weft thread that intersects with the longitudinally running ultra-fine wire bundle is less than 1/10 of the longitudinally running ultra-fine wire bundle, so the weft thread has a flow rate with respect to the working fluid. There is extremely little risk of inhibiting the flow, and therefore the pressure loss between the liquid phase working fluid and the gas phase working fluid is small, and therefore heat can be transported over long distances. In addition, since the ultra-fine wire bundle is knitted and integrated by the weft, it can be easily inserted into the sealed tube that forms the exterior body, and the ultra-fine wire bundle is knitted by the weft. In addition, the weft threads are arranged at regular intervals, so the ultra-fine wire bundles do not shift due to vibrations, etc., so the distribution of the ultra-fine wire bundles can always be uniform, resulting in long-term lifespan. Effects such as being able to maintain heat transport ability in a good state throughout the period can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG.
The figure is a front view showing the heat pipe expanded, and FIG. 4 is a diagram showing the experimental results, and is a diagram showing the temperature distribution in the axial direction of the heat pipe. 1...Heat pipe, 2...Sealed tube, 3...Superfine wire bundle, 4...Witch, 5...Press tool, 6...
Weft.

Claims (1)

[Claims] 1. A heat pipe in which a wick that generates capillary pressure is attached to the inner circumferential surface of a sealed tube and a working fluid is sealed in the sealed tube, in which the wick has a large number of longitudinally extending ultra-fine wicks extending along the axial direction of the sealed tube. It has an integrated structure in which a wire bundle is knitted with weft threads that intersect the ultra-fine wire bundle and are arranged at regular intervals along the axial direction of the sealed tube, and the weft threads for the longitudinally-aligned ultra-fine wire bundle are knitted. A wick made of ultra-fine wire, characterized in that the volume ratio is set to 0.1 or less, and the wick is brought into close contact with the inner circumferential surface of the sealed tube by a presser inserted into the inner circumferential side of the wick. Heat pipe with.