JPS6166086A - Heat pipe - Google Patents

Abstract

PURPOSE:To obtain a heat pipe which has no reversible heat transfer characteristic and which is capable of transferring heat only in one direction, by the provision of wick made of a shape memory alloy. CONSTITUTION:A wick 20 is made in the form of a net by intertwining a shape memory alloy wire. In its appropriate temperature condition, the wick has suitable meshes 1a and 1b as shown and performs its intrinsic function, that is, allowing a liquid to flow thereon due to a surface tension. When the temperature elevates to exceed the transformation temperature of the shape memory alloy, the net structure of the wick is deformed to contract itself in the direction of the thickness thereby interrupting the flow of the operating fluid. Thus, as the heat pipe transfers heat only in one direction, it is possible to use the wick in a variety of applications including the collection of heat from a heat source showing severe temperature variations.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to heat pipes.

(Prior Art) An example of a conventional heat pipe is shown in FIG. 5, in which a working fluid is sealed inside a sealed tube (1), and one end (
1 (Z) is placed in a high temperature atmosphere, and the other end (Ih) is placed in a low temperature atmosphere. and each end (1α) of the tube (1),
(Ib) has fins on the outer surface to increase the amount of heat transfer.
21, (31) are provided, and a wick (4) is provided on the inner surface of the tube (1).

The vapor of the working fluid moves through the center of the tube (11) to the low-melting end (IA), where it is cooled and condensed into liquid.

The liquid working fluid moves through the wick (4) to the high temperature end (1α) due to surface tension, where it is heated and evaporated. Due to the above circulation of the working fluid, the heat absorbed at the high side end (1) is sent to the low temperature side end (1b).The l end (1cL) is placed in a low temperature atmosphere, and the other end (1h) t,
6 If placed in a high temperature atmosphere, heat will flow from the end (1b) to (lα)
will be transferred to.

(Problem to be solved by the invention) In space bases, space satellites, slabs, etc., the heat generated by people and equipment inside the space is radiated into space through radiators installed on the outside. When a heat pipe is used, heat is radiated from the radiator when the radiator faces a cold, dark area, but when the radiator faces the sun due to the rotation of the satellite, the radiator is heated by the sunlight.
There is a problem with heat flowing back inside the satellite.

(Means for Solving the Problems) The present invention aims to eliminate the reversibility of heat transfer and provide a heat pipe that can transfer heat only in one direction. The flow of a liquid working fluid at a temperature below or above a specified temperature? : A heat pipe characterized by having a wick that blocks the heat.

(Embodiment) An embodiment of the present invention is shown in FIG. 1, in which (Ia) is a partial perspective view of the quick under appropriate temperature conditions;
(Ib) Figure is a sectional view taken along line A-A in Figure (Ia).
Fig. la) is a partial perspective view of the wick under inappropriate temperature conditions, and Fig. (Ilb) is a sectional view taken along line A--A in Fig. (Ia).

The wink blade is made into a net shape by braiding shape memory alloy wires. and under appropriate temperature conditions (I
As shown in a) and (Ib), appropriate voids are formed to allow the wick's original function, that is, to allow the liquid working fluid to flow due to its surface tension.

When the temperature rises and exceeds the transformation temperature of the shape memory alloy, G[a
) As shown in (Irb), the net deforms and contracts in its thickness direction, blocking the flow of the liquid working fluid.

FIG. 3 shows a second embodiment of the invention, in which a reticulated wick made of a shape memory alloy is continuous under suitable temperature conditions (as shown in FIG. 11, but under unsuitable conditions). Under certain temperature conditions (as shown in Figure Ill), it contracts in the length direction and becomes discontinuous, blocking the flow of the liquid working fluid.

A third embodiment of the present invention is shown in FIG. Under these conditions, it contracts in the circumferential direction as shown in Figure (I[) and blocks the flow of the liquid working fluid.

Therefore, if one end (10α) of the heat pipe 0 according to the present invention is located inside the space satellite and the other end (ioh) is located in the outside world as shown in Figure 4 (a), the outside world will be at a low temperature. In this case, the temperature gradient will be as shown by the solid line 501 in Figure 4 (portion C), and the central part where the wick is located will be at a temperature between the internal temperature and the outside temperature, and at this temperature the quick will become liquid. Set to allow flow of working fluid. Then, if the outside temperature rises, Figure 4 (b)
If there is a temperature gradient as shown by a broken line 502, the temperature at the center where the wick is provided rises. At this temperature, the wick deforms beyond the transformation temperature of the shape memory alloy, blocking the flow of the liquid working fluid, and the heat pipe does not transfer heat.

Note that in the above embodiment, the transfer of heat is stopped when the temperature rises, but depending on the method of manufacturing the shape memory alloy, it is possible to stop the transfer of heat when the temperature falls. .

(Operations and Effects of the Invention) Although the embodiments have been specifically described above, the heat pipe of the present invention includes a wick that is made of a shape memory alloy and blocks the flow of liquid working fluid at a temperature below or above a predetermined temperature. Under appropriate temperature conditions, the wick will perform its original function, i.e., allow the flow of liquid working fluid, but if the wick temperature changes beyond a predetermined temperature, i.e., the transformation temperature of the shape memory alloy, the wick will deform. to shut off the flow of liquid working fluid and stop heat transfer.

In this way, since this heat-ξ-wave transfers heat only in one direction, it can be widely used for heat recovery from heat sources with rapid temperature changes.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the invention, of which (Ia) is a partial perspective view of the wick under suitable temperature conditions (It
)) The figure is (Ia) A sectional view along line A in figure A, (II
a) The figure is a partial perspective view of the wick under unsuitable temperature conditions, (Figure H is Cma) a sectional view taken along the line A-A of the figure. FIG. 2 shows a second embodiment of the present invention, (I) is a longitudinal cross-sectional view showing the state under appropriate temperature conditions, (Il
FIG. 1 is a vertical cross-sectional view showing the state under inappropriate temperature conditions. 3 shows a third embodiment of the present invention, (I) is a cross-sectional view showing the state under appropriate temperature conditions, (II)
) is a cross-sectional view showing the situation under inappropriate temperature conditions. Fig. 4 is an explanatory diagram for explaining the operating principle of the present invention, (a) is a layout diagram of the heat pipe, and (b) is a diagram of the same arrangement as above, sub-agent, patent attorney Shigefumi Okamoto, and 3 others. Figure 1 Figure 2 (I) (II) Figure 4

Claims (1)

[Claims] 1. A heat pipe comprising a wick made of a shape memory alloy that blocks the flow of a liquid working fluid at a temperature below or above a predetermined temperature.