JPH0630672U - Corrugated heat pipe - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the heat transport characteristics of a corrugated heat pipe by activating the evaporation of the working fluid in the accumulation part of the working fluid. When a corrugated pipe 20 is used as a sealed pipe for enclosing a working fluid in a heat pipe, a plurality of narrow grooves 21 extending in the longitudinal direction of the pipe 20 are formed on the inner surface of the corrugated pipe 20.
Was formed. Therefore, even when the corrugated pipe 20 is used in a horizontal state, the evaporation and boiling of the liquid phase working fluid retained in the recessed portion on the lower side thereof are activated by the action of the narrow groove 21.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a corrugated heat pipe using a corrugated tube as a sealed tube for enclosing a working fluid.

[0002]

[Prior art]

 For example, when cooling the inside of a cave for power transmission cables with a long heat pipe that reaches several thousand meters, it is necessary to bend and install the heat pipe according to the bend and swell of the cave, and to prevent thermal expansion. In order to absorb it, it is necessary to bend the heat pipe into a predetermined shape at multiple points along the way. On the other hand, when installing a long heat pipe that is often bent in the field in a cave that is narrow and poor in workability, in order to improve the workability even a little, use a closed pipe for enclosing the working fluid in the heat pipe. A corrugated pipe that can be easily bent is used.

[0003]

[Problems to be solved by the device]

 However, when the corrugated pipe is used as the sealed pipe for enclosing the working fluid, if the evaporation part of the heat pipe is installed horizontally as shown in FIG. 3, the liquid-phase working fluid L of this heat pipe will cause the lower part of the corrugated pipe 20. There is a problem that the working fluid stays in the recess 20a and a thick liquid film is formed in this portion, so that evaporation or boiling of the working fluid hardly occurs. Especially for long heat pipes intended for long-distance heat transport, if the liquid-phase working fluid does not stay in the sealed pipe for enclosing the working fluid and smooth evaporation does not occur, the amount of heat transport decrease will be large. , The heat pipe capacity is significantly reduced.

The present invention has been made in order to solve the above problems, and an object thereof is to provide a corrugated heat pipe capable of actively causing evaporation or boiling of a working fluid. is there.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a corrugated heat pipe using a corrugated tube as a sealed tube for enclosing a working fluid, wherein the corrugated heat pipe has a corrugated shape. A plurality of narrow grooves extending in the longitudinal direction of the pipe are formed on the inner surface of the pipe.

[0006]

[Action]

 If the sealed pipe for enclosing the working fluid of the heat pipe is configured with a corrugated pipe, when the evaporating part of the heat pipe is arranged horizontally, the liquid phase working fluid is retained at the bottom of the corrugated pipe of this evaporating part. Occurs. Even in this stagnation part, since the surface area is increased by forming the narrow groove on the inner surface of the corrugated pipe, the amount of heat transfer to the working fluid increases, and the evaporation or boiling of the working fluid becomes active. The amount of heat transport as a heat pipe increases.

[0007]

【Example】

 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a conceptual perspective view of a heat pipe type cooling device for cooling the inside of an underground cave. In the figure, 1 is a long loop type heat pipe consisting of an evaporation section 10 and a condensation section 11. Shows. The heat pipe 1 is a vacuum degassed closed tube in which a fluid such as CFC or alcohol that evaporates and condenses in a target temperature range is enclosed as a working fluid. The evaporation section 10 absorbs heat from the outside. After evaporating the working fluid and moving this working fluid to the condensing section 11, the condensing section 11 cools and condenses the working fluid vapor, and the heat absorbed by the evaporating section 10 is transferred to the outside by the condensing section 11. To release. The loop heat pipe is a heat pipe configured so that a vapor passage for a working fluid and a liquid recirculation passage are separated to form a circulation pipe as a whole.

The evaporation part 10 of the heat pipe 1 is installed over a long section in the cave 3 where the underground power cable 5 is laid, and absorbs heat generated from the power cable 5 in the cave 3. The condensing part 11 of the heat pipe 1 is installed outside the cave 3 and is forcibly cooled by the refrigerator 2. In this case, the condensing part 11 of the heat pipe 1 is installed at a position higher than the evaporating part 10, and the liquid is refluxed by the action of gravity.

The evaporation section 10 of the heat pipe 1 communicates with the condensing section 11 by a liquid tube section 10 a for a liquid phase working fluid serving as an outward tube and a steam tube section 10 b for sending working fluid vapor to the condensing section 11. Has been done. Therefore, the circulation line is formed as a whole.

As shown in FIG. 1, a corrugated pipe 20 that is easy to bend and has a compressive strength is used for the closed pipe that is the container of the heat pipe 1, and the corrugated pipe inside the narrow cave 3 is used. The installation work of the heat pipe 1 is facilitated. The corrugated pipe 20 is a normal cylindrical pipe having a corrugated shape in the longitudinal direction thereof, and the corrugated shape may be concentric or spiral.

Further, in particular, on the inner surface of the corrugated pipe 20 of the evaporation portion 10 of the heat pipe 1, as shown in FIG. 1, a plurality of fine grooves 21 extending in the longitudinal direction of the pipe are formed in the circumferential direction of the pipe. ing. The narrow groove 21 has a width size and a depth ranging from several hundreds μm to several mm, and a circumferential pitch ranging from several hundreds μm to several mm. The size and pitch are the same as those of the corrugated pipe 20. A suitable one is selected according to the size of the unevenness of the formed corrugation. The cross-sectional shape of the fine groove 21 may be rectangular, trapezoidal, arcuate, or the like, and the shape in the longitudinal direction thereof may be linear or spiral.

The corrugated pipe 20 having the narrow groove 21 is formed by, for example, forming a pipe by spirally bending and welding a metal tape having a predetermined groove on the inner surface side of the pipe. It can be easily manufactured by corrugating this pipe from the outside through a mold or the like.

Next, the operation of the evaporation unit 10 of the heat pipe 1 in which the plurality of narrow grooves 21 are formed on the inner surface of the corrugated pipe 20 will be described. When the evaporation unit 10 of the heat pipe 1 is installed horizontally, a corrugated portion is formed on the lower side of the corrugated pipe 20 that constitutes the evaporation unit 10, but the working fluid in the liquid phase accumulates in this concave portion and stays there. There is a strong tendency to If the inner surface of the corrugated pipe, which is in direct contact with the working fluid, is thickly covered with the liquid-phase working fluid, evaporation / boiling of the working fluid is hindered, and it becomes difficult to absorb heat in this portion. However, by forming the above-mentioned narrow groove 21 in the corrugated pipe 20, the contact area between the liquid-phase working fluid and the corrugated pipe 20 is increased, and even if the liquid film is thick, the working fluid is not evaporated or boiled. Become active.

By constructing the container of the long heat pipe 1 with the corrugated pipe 20 as described above, the workability of the heat pipe 1 at the site is improved and the liquid in the evaporation unit 10 is improved. Even if the phase working fluid stays, the multiple narrow grooves 21 are formed to activate evaporation and boiling of the working fluid in the stagnant portion, and as a result, the entire working length of the evaporation section 10 is increased. The working fluid can be evaporated smoothly. Therefore, it is possible to increase the heat transport amount of the horizontally installed corrugated pipe type heat pipe 1.

In the above embodiment, the corrugated tube 20 having the narrow groove 21 is used only in the evaporation section 10 of the heat pipe 1, but the corrugated tube 20 having the narrow groove 21 is also used for other purposes. can do.

In addition to the long loop heat pipe 1 as described above, a heat pipe using a non-loop type corrugated pipe or a relatively long loop type heat pipe used for snow melting on the road surface is used. Even for a heat pipe or the like using a short corrugated pipe, the same effect can be obtained by forming a plurality of thin grooves on the inner surface of the evaporation portion.

[0017]

[Effect of device]

 As is clear from the above description, according to the present invention, when a corrugated pipe is used as a sealed pipe for enclosing a working fluid, a plurality of narrow grooves oriented in a predetermined direction are formed on the inner surface of the pipe. Therefore, the evaporation and boiling of the working fluid can be activated even in the staying portion of the liquid-phase working fluid, and the heat transport characteristics of this type of heat pipe can be improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view of a corrugated tube used as a sealed tube for enclosing a working fluid in an evaporation section of a heat pipe.

FIG. 2 is a perspective view conceptually showing a heat pipe type cooling device.

FIG. 3 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

1 ... Heat pipe, 20 ... Corrugated pipe, 21 ... Fine groove.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Masahiko Ito 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Creator Yuuji Saito 1-5-1, Kiba, Koto-ku, Tokyo Fujikura (72) Inventor Fumiaki Aoyama 1-5-1 Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A corrugated heat pipe using a corrugated tube as a sealed tube for enclosing a working fluid,
A corrugated heat pipe, wherein a plurality of narrow grooves extending in the longitudinal direction of the corrugated pipe are formed on the inner surface of the corrugated pipe.