KR20020077696A - Heat pipe with sintered wick structure - Google Patents

Abstract

PURPOSE: A heat pipe with metallic powder sintered wick structure having superior capillary phenomenon manufactured by injecting an operating fluid into the pipe and sealing the pipe under vacuum after covering and sintering metal powder on a metal plate to a certain thickness and forming the metal plate in a cylindrical pipe is provided. CONSTITUTION: The method for manufacturing a heat pipe(10) comprises the processes of covering metal powder with a particle size corresponding to a sieve size of 100 to 250 meshes on a metal plate to a certain thickness of 0.2 to 2 mm; sintering the metal powder covered metal plate in a vacuum furnace or a reduction environment furnace of a mixed gas of nitrogen and hydrogen, or hydrogen and argon gas at a temperature ranging from 700 to 1500 deg.C for 10 minutes to 3 hours; forming the sintered metal plate in a cylindrical shape; and injecting an operating fluid into the formed pipe with wick(12) structure, and forming a sealing part(18) by sealing both ends(11a,11b) of the operating fluid injected pipe with wick(12) structure under the vacuum state at the same time, wherein irregular grooves, V and U shaped fine grooves are formed on the metal pipe in a length direction of the pipe, the metal powder is covered and sintered on parts where irregular grooves, V and U shaped fine grooves are formed on the metal pipe in a length direction of the pipe, and the metal powder is copper powder, 1 to 10 % tin powder alloyed to copper and 1 to 10 % zinc powder mixed with copper are used in the copper powder to promote sintering.

Description

HEAT PIPE WITH SINTERED WICK STRUCTURE}

The present invention relates to a heat pipe, and more particularly, to coat and sinter a metal powder to a metal plate to a certain thickness, process it into a cylindrical pipe, and then sinter the metal powder having excellent capillary effect, which is made by injecting and sealing a working fluid under vacuum. Wick structure heat pipe.

Conventional capillary development heat pipes have a thin and fine metal mesh attached to the inner wall of the metal pipe, form a dense and fine groove on the inner wall of the metal pipe, or methyl alcohol, acetone, When one end of a heat pipe in which a working fluid such as water (distilled water) is injected is heated by an external heat source, the working fluid evaporates at the heated end, and the evaporated working fluid is not heated through the hollow portion of the heat pipe in a gaseous state. Moving to the other end, the latent heat of evaporation is transferred around the outside of the heat pipe to condense, and the condensed fluid returns to the heating site, ie, to the end by capillary action through a metal mesh or groove and evaporates again. The delivery is configured to take place.

Conventionally, a heat pipe using such a dense metal mesh has been most used, but such a heat pipe has to adhere a dense metal mesh to the inner wall of the entire pipe, so that the heat pipe is difficult to manufacture when the heat pipe is thin or long, thus manufacturing cost Will rise. In addition, when the heat pipe needs to be bent, it is quite difficult to bond the metal mesh to the inner wall while the pipe is bent, and when the heat pipe is manufactured after bending the metal mesh, the metal mesh is damaged in the bent portion. There was a problem that the heat transfer is not good. In addition, such a heat pipe has a problem that the working fluid movement force is low due to the capillary phenomenon.

Due to this problem, a wick having a relatively good working fluid movement force due to a capillary phenomenon is present in the form of a wick sintered with a metal powder sintered with metal powder on the inner wall of the pipe. Since the fluid flow force is relatively good due to the capillary phenomenon through these pores, the thermal conductivity is excellent. However, such a heat pipe is placed in the center of the pipe and sintered after filling the metal powder between the pipe and the rod. Since the manufacturing process is complicated and the manufacturing cost is high.

In order to solve the above problems, the present invention is a new type of production method that is completely different from the conventional method, and the manufacturing process of the heat pipe using a dense groove and a fine one or a metal mesh or a combination of both is difficult and the manufacturing cost is high. On the contrary, the heat pipe of the wick structure using the sintered metal powder sintering has a relatively good working fluid movement force due to capillary action, but the manufacturing process is complicated and the price increases. In order to solve the problem that the powder is difficult to insert at the same time, the present invention improved the production method completely different from the conventional production method in the prior art when manufacturing the heat pipe in the prior art to manufacture the wick insert into the pipe or inserted into the pipe, Mass production is difficult because the metal powder is added and sintered. First of all, metal powder is coated on a metal plate to a certain thickness, and then processed into a cylindrical shape, which is not only easy to mass-produce, but also easy to manufacture a long heat pipe, and a narrow diameter heat pipe can be used by drawing a wide tube. The heat pipe can be easily manufactured.

1A is a side view of a metal plate coated with a metal powder of the invention and sintered

FIG. 1B is a front view of a pipe made of the metal plate of FIG. 1A cylindrically

Figure 2 is a longitudinal sectional view showing a heat pipe of the present invention

<Description of the symbols for the main parts of the drawings>

10: heat pipe 12: wick (WICK)

18: sealing part

The invention is now described in more detail with the accompanying drawings.

1A to 2 show the structure of the heat pipe 10 and the drawing method thereof according to the present invention.

The heat pipe 10 according to the present invention includes a hollow metal pipe 11 having both ends 11a and 11b sealed in a vacuum state, a wick 12 attached to an inner wall of the metal pipe 11, and a hollow pipe ( 11) It includes a working fluid filled therein and a manufacturing method thereof.

Heat pipe 10 of the present invention configured as described above is connected to each other by welding as shown in Figure 1b both sides of the metal plate 13 is attached to the wick 12 is fired metal powder as shown in Figure 1a To produce a pipe, and the both ends 11a and 11b of the pipe are sealed in a vacuum state as shown in FIG.

In the method of manufacturing the metal plate 13 with the wick 12 shown in FIG. 1A, 100 to 250 mesh metal powder is coated on the metal plate 13 to a predetermined thickness of 0.2 to 2 mm under vacuum at a temperature of 700 to 1500 ° C., Sintering is carried out for 10 minutes to 3 hours in a reducing atmosphere furnace of nitrogen, hydrogen, or a reducing gas of a mixed gas in which hydrogen and argon gas are mixed.

Since the heat transfer of the heat pipe 10 is made through the pipe wall of the metal pipe 11, the metal plate 13 is excellent in thermal conductivity and copper and iron which can sufficiently withstand the pressure inside the sealed heat pipe and can be used for a long time use. Manufactured from aluminum and stainless steel, but mainly copper. Slotted metal plates may also be used to speed up the flow of the working fluid. In addition, the metal plate (13) in the longitudinal direction in order to accelerate the flow of the working fluid and increase the heat dissipation area A fine grooved metal plate having a V U shape may be used.

The metal powder of the wick 12 includes copper, iron, aluminum, and stainless steel, but mainly copper powder is used. The particle diameter is 100-250 mesh spherical particles, preferably 150 mesh size. In some cases, in order to achieve sintering quickly, a powder in which tin is alloyed with 1 to 10% of copper or a powder in which zinc is mixed with 1 to 10% of copper may be used.

Preferable temperature for sintering copper or copper alloy powder is about 850 degreeC-950 degreeC. In the case of 850 degreeC or less, a sintering time will become slow and in the case of 950 degreeC or more, there exists a possibility that a copper powder may melt | dissolve and a preferable wick structure cannot be formed. In order to prevent oxidation, sintering is performed in a reducing atmosphere furnace for 10 minutes to 3 hours. Sintering is not continued within 10 minutes, and copper powder is melted for 3 hours or more, thereby making it difficult to form fine pores.

The working fluid is a liquid such as ammonia, freon, methanol, water, and an organic medium (acetone) having excellent vaporization. Working fluids are classified as shown in Table 1 below, depending on the operating temperature range and their compatibility with the vessel material.

Operating temperature (℃) Working fluid Compatibility with container material (0: suitable X: not suitable) iron Copper aluminum Stainless steel -60 to 50 ammonia 0 X 0 0 -40 to 120 Freon 0 0 0 10 to 200 Methanol 0 X X 30 to 200 water X 0 X X 150 to 300 Organic medium 0 0 0

The sealing unit 18 may be attached by sealing a metal or plastic cap, or may be sealed by PVC, bakelite, Teflon, or the like.

(Example)

150 mesh copper powder is uniformly coated on a copper plate made of rolls 600 mm wide and 0.7 mm thick to 0.6 mm thick and sintered in a continuous heat treatment furnace at 800 to 1000 ° C. for 30 minutes to 2 hours. After fabricating a metal plate, a pipe having a diameter of 38.7 mm was cut into several rolls (Rol) l and a pipe having a diameter of 12.70 mm with a wick as shown in FIG. At this time, phosphorus ("P") in the copper solder prevents oxidation of copper.

The pipe thus made was cut to 300 mm in length, and both ends 11a and 11b of the pipe were condensed as shown in FIG. To complete.

Conventional capillary development type heat pipe has a problem that the manufacturing process is complicated and expensive by mainly inserting or firing metal mesh or sintered metal powder into the pipe, but in the present invention, as described above, the metal plate coated and fired on the metal plate By manufacturing and using the pipe after the process, not only is the process simpler than the prior art, but also the wick and the metal plate are completely attached by sintering so that the bendability is good. It also has an excellent effect on sex and economics.

Claims (4)

100-250 mesh metal powder was coated on the metal plate 13 in a constant thickness of 0.2-2 mm, and then in a vacuum furnace at a temperature of 700 ° C. to 1500 ° C. or a reducing atmosphere of a mixed gas mixed with nitrogen, hydrogen, hydrogen, and argon gas. A method of manufacturing a heat pipe, characterized in that the metal plate (FIG. 1A) sintered for 3 minutes to a cylindrical shape (FIG. 1B) is processed into a cylindrical shape (FIG. 1B), and the working wick structure is sealed while injecting a working fluid under vacuum. The method of manufacturing a heat pipe according to claim 1, wherein the metal plate (13) is formed with grooves, grooves and V-shaped fine grooves in the longitudinal direction of the pipe. The method of manufacturing a heat pipe according to claim 1, wherein the metal plate (13) is formed by coating and sintering a metal powder in a portion where the uneven groove, the V and the U-shaped fine grooves are formed in the longitudinal direction of the pipe. The metal powder according to claim 1, 2 or 3, wherein the metal powder is copper powder, and to promote sintering, powders alloyed with copper 1-10% tin and powders mixed with zinc 1-10% zinc are used. Method for producing a heat pipe, characterized in that.