JPS58106388A - Heat pipe and production thereof - Google Patents

Abstract

PURPOSE:To contrive to enhance heat transfer peformance, by a method wherein a supporting pipe provided with small holes at both end parts thereof is concentrically fitted into an outer casing pipe, and a porous particles and a working fluid are sealed between the pipes, in a heat pipe with porous wick. CONSTITUTION:A supporting pipe 3 is concenterically fitted and fixed in an outer casing pipe 2, and small through-hole 3a are provided at both end parts of the pipe 3. Adsorptive porous particles 4 of synthetic zeolite or the like are packed between the outer casing pipe 2 and the supporting pipe 3 in the condition of close contact with each other, a working fluid is poured between the pipes 2 and 3, and both ends of the pipes are closed by end plates 5a, 5b. In this construction, the vapor of the working fluid flows along the inside periphery of the pipe 3 from one end side to the other end side, and releases heat. The condensed liquid of the working fluid enters into the layer of the porous particles 4 through the small holes 3a, and is returned to a heating part by passing between the particles. Accordingly, since a capillary pressure is generated in the entire part of the layer of the particles 4, a high capillary pressure can be obtained, and heat transfer capability can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type of heat pipe using a porous material, and a method for manufacturing the same. It forms a reflux path and generates the capillary pressure necessary to reflux a one-liquid phase working fluid. Conventionally, the wick is made of metal mesh, porous sintered metal, or 61 (61) formed on the inner surface of an exterior pipe. group) is known. By the way, the maximum capillary pressure Pmaz
Among the above wicks, for those made of metal mesh or porous sintered metal, the maximum capillary pressure Pm&X
If the effective capillary radius re is made as small as possible in order to increase There were drawbacks. In addition, in the case of lie and ri, the flow resistance is small because there is nothing that crosses the streamline of the liquid-phase working fluid, but on the other hand, the effective capillary radius re is large, so the maximum capillary pressure Pm&g obtained is small, and the shift For example, this method has drawbacks such as being unsuitable for a top heat mode in which the heating section is set at a high position and a one-liquid phase working fluid is refluxed against gravity.

This invention was made in view of the above circumstances, and is intended to produce a heat pipe with high capillary pressure and low flow resistance to liquid-phase working fluid, in other words, a heat pipe with high capacity for transporting materials, and the heat pipe. The purpose is to provide a method for

Embodiments of the present invention will be described below with reference to the attached drawings. ◇ First, an embodiment of the heat pipe of the present invention will be explained. 1. Figure 1 is a vertical cross-sectional view, and Figure 2 is a longitudinal cross-sectional view of the heat pipe.
1 is a sectional view taken in the direction of arrow 1, in which a support pipe 3 having a smaller diameter than the outer pipe 2 and having small holes 3a at both ends that are open to the inner and outer circumferential surfaces is inserted almost concentrically into the interior of the outer pipe 2.・Porous particles 4 are placed between each of these pipes 2 and 2 in a state in which they are in close contact with each other, 1 and a working fluid is injected inside, and both ends are sealed with end plates 5a and 5b. has been done. Here, the porous particles 4 are particles of synthetic zeolite, activated aluminium, etc., which are known as adsorbents, preferably particles of about 100 mesh, and the gaps between the particles 4 exhibit liquid phase operation. Since the pores that constitute the main flow path of the liquid and that the particles 4 themselves have are micropores with a diameter of about 10-4 to 1O-5IIs1, high capillary pressure is generated. 4
As a whole, it acts as a wick.

Therefore, in the heat pipe 1 having the above configuration, when heat is applied to one end of the heat pipe, the internal working fluid evaporates and vaporizes, and the vapor flows through the inner peripheral side of the support pipe 3 to the other end. At the other end, heat is radiated and S condenses and liquefies.
After the liquid-phase working fluid passes through the small hole 3a formed in the support pipe 3 and enters the layer made of porous particles 4, 1 mainly uses the gaps between the particles 4 as a flow path to the one end, that is, the heating section side. Heat transport is carried out by repeating this circulation flow of the working fluid.

In the heat pipe 1 described above, the capillary pressure for refluxing the liquid-phase working fluid is generated not only in the gaps of the porous particles 4 on the heating section side but also in the pores of the porous particles 4 themselves. As mentioned above, the pores are micropores with a diameter of about 10 to 1011%, so it is possible to obtain an unprecedentedly high capillary pressure, and the liquid phase working fluid is made of porous particles that are in close contact with each other. M with the gap as the main flow path? +tt, the operating resistance against the liquid-phase working fluid can be significantly reduced compared to conventional heat pipes that use metal mesh or porous sintered metal as the wick. Therefore, in the heat pipe 1 described above, the capillary pressure is high and the flow resistance to the liquid-phase working fluid is low, and in addition, the return path for the liquid-phase working fluid and the flow path for the gas-phase working fluid are separated by the support vibro. Therefore, even if the flow rate of the gas-phase working fluid is high, the liquid-phase working fluid that is flowing back to the heating part side will not be torn off and scattered by the gas-phase working fluid on the way, resulting in a high Heat transport ability can be obtained.

Note 1: In the above heat pipe, the support pipe 3
In some cases, it is necessary to make the small pores 3a smaller than the particle size of all porous particles 4;
It is sufficient to wrap a wire mesh with a mesh smaller than the grain size around the support vibro.

Next, the procedure for manufacturing the heat pipe 1 described above, that is, the manufacturing method of the present invention will be explained. First of all, use the base pipe for the dopipe, that is, the exterior pipe 2.The exterior pipe 2 may be any suitable metal pipe such as a 1&14 pipe or an aluminum pipe, but it is preferable to use one with good thermal conductivity. The surrounding surface should be thoroughly cleaned by degreasing, etc. When a support pipe 3 having a smaller diameter and having small holes 6a formed at both ends is inserted into the exterior pipe 2 almost concentrically as shown in FIG. 6(2), the exterior pipe 2
An end plate 5b is attached to one open end of the opening to seal it.

As a means for attaching the end plate 5b, TIG welding or brazing welding may be employed. After that, the exterior pipe 2
Between the support vibro and the supporting vibro, porous particles 4 of about 100 mesh, such as synthetic zeolite or activated alumina, are placed between the
). The particles 4 are then applied to each pipe 2.6 to reduce the distance between the sheathing pipe 2 and the support pipe 3. Methods for this include expanding the support vibro by bulging the support pipe 3 or inserting an appropriate plug into the support pipe 3, or inserting the support pipe 3 and porous particles 4 into the exterior pipe 2. After inserting the outer pipe 2 as described above, the diameter of the outer pipe 2 is reduced by drawing the outer pipe 2, or the outer pipe 2 is heated and expanded in advance, and the support pipe 3 and porous particles are inserted in that state. 4 may be inserted into the exterior pipe 2 as described above, and then the exterior pipe 2 may be cooled and reduced in diameter. In addition, when carrying out the method described in 1- in order to narrow the interval between each pipe 2.6, appropriate sealing means is applied to prevent the porous particles 4 from leaking from between each pipe 2.3. Of course.

Next, as shown in FIG. 3, an end plate 5a having an injection pipe 6 is attached to the other open end of the exterior pipe 2 to close it. A suitable working fluid is sealed inside. The working fluid may be sealed by a conventional method, and for general reference, after the non-condensable gas in the exterior pipe 2 is vacuum-suctioned and exhausted through the injection pipe 6. , an appropriate amount of working fluid is injected into the exterior nozzle 2 through the injection pipe 6, 1 the injection pipe 6 is crushed and sealed, and 1 is cut off at the tip end side of the sealed part. good.

As is clear from the above description, according to the present invention, the porous particles filled between the exterior pipe and the support pipe inserted therein so as to be in close contact with each other function as a wick, so that the particles themselves have fine pores. Because it has a high capillary pressure, it is possible to generate a high capillary pressure, and at the same time, since the particles are closely attached to each other without using a binder, the gaps between the particles become flow paths for the liquid phase working fluid ( Therefore, according to the present invention, the liquid phase drawing fluid can be efficiently refluxed to the heating part side, so that a heat pipe with high heat transport ability can be obtained. Moreover, in the method of the present invention, by narrowing the gap between the exterior pipe and the support pipe, the porous particles filled between them are brought into close contact with each other. There is no possibility that the pores of the particles themselves will be blocked, and therefore a heat pipe with good performance can be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view showing one embodiment of the heat pipe of the present invention, Fig. 2 is a view taken along the line ■-■ in Fig. 1, and Fig. 3 (A
) CB)) are schematic cross-sectional views showing the manufacturing process according to the method of the present invention. 1... Heat pipe, 2... Exterior pipe, 3...
Support pipe, 3 &... small hole, 4... porous particle Applicant Fujikura Electric Cable Co., Ltd. Agent Patent attorney Taketo Toyota (1 person)

Claims (1)

[Claims] 1. Porous particles are filled in close contact with each other between the exterior pipe and a support pipe inserted substantially concentrically into the interior thereof and having small holes at both ends; A heat pipe with a working fluid sealed inside the pipe. 2. After inserting support pipes with small holes at both ends into the exterior pipe in a substantially concentric manner, 1. Filling the space between these pipes with porous particles, and then narrowing the interval between each of the pipes. A method for manufacturing a heat pipe, comprising: bringing the porous particles into close contact with each other; then sealing the exterior pipe; and after evacuating the non-condensable gas inside the exterior pipe, a working fluid is injected into the exterior pipe. 6. A heat pipe manufacturing method according to claim 2, characterized in that the support pipe is expanded in order to narrow the distance between the pipes so that the porous particles are brought into close contact with each other. In order to narrow the distance between the pipes so that the porous particles are brought into close contact with each other, the outer pipe is subjected to a drawing process after being filled with the porous particles to reduce the diameter of the outer pipe. A method for manufacturing a heat pipe according to claim 2. 5. In order to narrow the distance between the pipes in order to bring the porous particles into close contact with each other, the exterior pipe is heated and expanded in advance, and in this state, the support pipe is inserted into the exterior pipe, and 1. 3. The method of manufacturing a heat pipe according to claim 2, wherein porous particles are filled between the pipes, and then the outer pipe is cooled and reduced in diameter.