KR20060033624A - Heat pipe manufacturing method and heat pipe manufactured by the method - Google Patents

Abstract

The present invention relates to a heat pipe manufacturing method and a heat pipe manufactured by the method, the pipe is sealed in a vacuum state, the working fluid contained in the pipe, and the metal powder is sintered on the inner wall of the pipe Claims [1] A method for manufacturing a heat pipe comprising a formed sintering wick, the method comprising: applying a binder to an inner wall of the pipe; Sprinkling metal powder on a binder applied to an inner wall of the pipe; A sintering step of sintering the metal powder to form a sintered wick; An injection step of injecting a working fluid into the pipe; And a vacuum sealing step of vacuuming and sealing the pipe. According to the heat pipe manufacturing method of the present invention, there is an effect that the heat pipe is simple, the production cost is low, and the thickness of the sintered wick is thin and the overall uniformity, so that the heat pipe excellent in efficiency and productivity can be produced.

Description

Method of manufacture heatpipe and heatpipe manufactured using the method

1 is a view for explaining the operation of the heat pipe produced by a conventional manufacturing method,

2a to eh 2d are views for explaining a conventional heat pipe manufacturing method,

3 to 6 are views for explaining a heat pipe manufacturing method according to the manufacturing method of the present invention.

7 is a view for explaining another embodiment of the heat pipe according to the manufacturing method of the present invention,

8 is a view for explaining another embodiment of the heat pipe according to the manufacturing method of the present invention,

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

1, 1a, 1b ... heat pipe 10 ... pipe

12 ... inner wall 20 ... working fluid

30 ... Sintered wick 32 ... Metal powder

40 ... Binder 50 ... Coating Rod

52 ... rod part 54 ... applicator part                 

60, 62 ... stopper

The present invention relates to a method for manufacturing a heat pipe and a heat pipe manufactured by the method, and more particularly, to a method for manufacturing a heat pipe consisting of a pipe, a working fluid and a sintered wick, The present invention relates to a heat pipe manufacturing method capable of forming the thickness of a sintered wick thinly and uniformly without a mandrel used essentially, and a heat pipe manufactured by the method.

The heat pipe takes advantage of the latent heat caused by the phase change of the working fluid therein, and takes the heat from the heat source and transfers it to the heat sink.

Referring to Figure 1, the structure and operation of a general heat pipe will be described.

The heat pipe 100 includes a pipe 101, a sintered wick 102 and a working fluid.

The pipe 101 is in the shape of an elongated cylinder, the inside of which is vacuumed and sealed. The sintered wick 102 is provided on the inner wall of the pipe 101. The sintered wick 102 is formed by sintering metal powder and has a fine space therein. The working fluid 103 is present in the inner space of the pipe 101 or in the minute space inside the sintered wick 102.

The heat transfer process of the heat pipe 100 having such a configuration will be briefly described. When heat (H) is transferred to the heat absorbing portion 105 that is thermally coupled to a heat source (not shown), the working fluid, which is located in the sintering wick 102 of the heat absorbing portion 105, changes due to the gas phase. It absorbs a lot of heat. The working fluid in the gaseous state is rapidly moved to the heat generating unit 106 through the steam flow passage 104 as shown by the arrows shown in FIG. The moved gas transfers heat (H) to a heat sink (not shown) that is thermally coupled to the heat generating unit 106, and condenses to change into a liquid state. The working fluid in the liquid state is moved back to the heat absorbing portion 105 by capillary action. This operation is repeated and heat is transferred.

As described above, the conventional method of manufacturing the heat pipe 100 provided with the sintered wick is described with reference to FIGS. 2A to 2D.

A pipe 101 having a cross section is prepared (see FIG. 2A). In this case, an end forming portion 113 having a reduced diameter is formed at the lower end of the pipe 101.

The mandrel 110 having an outer diameter smaller than the inner diameter of the pipe 101 is inserted into the previously prepared pipe 101, and the metal powder 111 is inserted into the space formed between the inserted mandrel 110 and the inner wall of the pipe 101. ) (See FIG. 2B). In this state, the metal powder is heated in the electric furnace so as to be sintered. After the metal powder is sintered to become the sintered wick 102, the mandrel 110 inserted is removed.

After removing the mandrel 110 from the pipe 101, a stopper 112 is formed by a method such as welding to block the upper end of the pipe 101 (see Fig. 2C). Then, after the upside and downside of the pipe 101 is reversed, the working fluid is injected through the end forming part 113, the inside of the pipe 101 is vacuumed, and the end forming part 113 is welded or the like. It is sealed using the method to complete the heat pipe 100 (see FIG. 2D).

It is true that the heat pipe 100 manufactured by the conventional method as described above also performs better than any other means in terms of heat transfer. However, the conventional manufacturing method has various problems caused by using the mandrel 11 in the process of forming the metal powder into the sintered wick on the inner wall of the pipe.

In other words, it is difficult to insert the mandrel into the pipe to maintain a constant distance from the inner wall of the pipe, so first of all, the cost of the work is excessive, and the gap is filled with metal powder and then sintered. When the sintered wick is formed, the thickness of the sintered wick may not be constant. This may cause problems in the operation of the heat pipe.

In addition, the length of the heat pipe that can be manufactured is limited because the mandrel has to enter the inside of the pipe to maintain a constant spacing and to be removed after sintering again. At present, the heat pipe produced by the conventional method does not exceed 300mm. Therefore, it is impossible to manufacture a longer heat pipe.

In addition, since the sintering is performed while the mandrel enters the inside of the pipe, it is not easy to remove the mandrel after sintering itself, and during the removal process, the formed sintered wick is damaged by the mandrel, which may cause defects. Becomes high. The longer the pipe, the higher the probability of failure.                         

In addition, since the metal powder must be filled between the inner wall of the pipe and the outer circumferential surface of the mandrel while the mandrel is positioned inside the pipe, not only workability but also the thickness of the sintered wick formed by sintering the metal powder I cannot thin it to some extent. In fact, the heat transfer efficiency was tested using a heat pipe and found that reducing the space occupied by the sintering wick in the inner space of the pipe increased the space of the vapor flow passage through which the gaseous working fluid flows. In the case of using a pipe having a constant inner diameter, if the thickness of the sintered wick is reduced, the steam flow passage becomes wider, and the heat transfer efficiency is increased. However, in the case of the heat pipe produced by the conventional method, it is manufactured to about 0.7 mm or less. There is a problem that is difficult to do. In addition, when the thickness of the sintered wick is thinned, the working fluid moves better by capillary action.

Meanwhile, in the case of the heat pipe 100 produced by the conventional manufacturing method, referring to FIG. 2D, since there is no sintered wick in each of the lower end and the upper end, heat transfers are performed by the lengths h1 and h2 of the respective parts. Does not contribute significantly to As such, if there is a portion that occupies a volume while not contributing to heat transfer, if the heat pipe is actually used in any heat transfer apparatus, there may be a problem in the capacity of heat transfer as well as waste of space.

The present invention is to solve the above problems, without the use of a mandrel, a heat pipe manufacturing method and a heat pipe manufactured by the method so that a thin sintered wick can be formed uniformly on the inner wall of the pipe The purpose is to provide.

In order to achieve the above object, the present invention includes a pipe which is sealed in a vacuum state, a working fluid contained in the pipe, and a sintering wick formed by sintering metal powder on the inner wall of the pipe. A method of manufacturing a heat pipe, comprising: a coating step of applying a binder to an inner wall of the pipe; Sprinkling metal powder on a binder applied to an inner wall of the pipe; A sintering step of sintering the metal powder to form a sintered wick; An injection step of injecting a working fluid into the pipe; And a vacuum sealing step of vacuuming and sealing the pipe.

On the other hand, the step of applying a binder on the inner wall of the pipe, the coating having a rod portion that can be inserted into the inside of the pipe and the coating portion of the material provided at the end of the rod portion to apply the binder to the inner wall of the pipe It is preferably carried out by a rod.

In addition, the step of applying the binder on the inner wall of the pipe, it is also preferably carried out by the method of flowing a binder in a liquid state into the inside of the pipe.

In addition, the thickness of the sintered wick is preferably 0.1mm to 0.5mm.

On the other hand, the manufacturing method, the outer surface is flat, has the same cross-sectional shape as the pipe, it is preferable to further include a step of sealing at least one end of the both ends of the pipe with a stopper fitted to the pipe. .                     

In addition, the stopper is formed with a through hole penetrated in the thickness direction, and after injecting the working fluid through the through hole, the pipe is preferably sealed.

As another aspect of the present invention, a heat pipe is disclosed. The heat pipe includes a pipe sealed in a vacuum state, a working fluid contained in the pipe, and metal powder sintered on an inner wall of the pipe. In the heat pipe comprising a formed sintering wick (sintering wick), the sintered wick is characterized in that the metal powder is sprayed on the binder applied to the inner wall of the pipe and then sintered.

On the other hand, it is preferable that at least one end of both ends of the pipe has a flat outer surface, has the same cross-sectional shape as the pipe, and is provided with a stopper for sealing the pipe by being fixed to the pipe.

Hereinafter, a method of manufacturing a heat pipe according to the present invention will be described in detail with reference to the accompanying drawings. Figure 3 is a view for explaining the coating step in the manufacturing industry according to the present invention, Figures 4 and 5 is a view for explaining the step of spraying the metal powder, the sintering step, Figure 6 is a completed heat It is a figure which shows a pipe.

The heat pipe manufacturing method according to the present invention comprises a binder coating step, spraying a metal powder, a sintering step, a working fluid injection step and a vacuum sealing step.

The binder applying step is to apply the binder 40 to the inner wall 12 of the pipe 10. The binder 40, which is generally used in a sintering process, is viscous and, when applied to the inner wall 12 of the pipe 10, adheres to the inner wall 12 while maintaining a constant thickness. When the metal powder 32 to be described later is sprayed on, the metal powder 32 does not fall off from the inner wall 12 and serves to adhere to the inner wall 12 while maintaining a constant thickness. Then, the binder 40 is burned or evaporated by the heated heat during the sintering step to be described later, and after the sintering step, the sintering wick 30 formed from the metal powder 32 as well as the inner wall of the pipe 10. ) Will not remain.

On the other hand, if the type of oil used as the binder 40 is appropriately selected, the thickness of the metal powder 32 is applied to the inner wall 12 and maintained according to the viscosity of the selected oil can be adjusted to a desired degree. That is, the meaning of adjusting the thickness of the metal powder 32 means that the thickness of the sintered wick 30 formed according to the selection of the binder 40 can be adjusted.

In the case of the present embodiment, the step of applying the binder 40 is performed by the coating rod 50 (see Fig. 3). The coating rod 50 is composed of a rod portion 52 and an application portion 54.

The singer rod part 52 is a thin and long rod which can be inserted into the pipe 10. The application part 54 is provided at one end of the rod part 52. The application portion 54 is generally made of cloth or cotton such as cloth. Therefore, if the binder 40 is sufficiently buried and absorbed before being inserted into the pipe 10, and then passed through the inside of the pipe 10, the binder 40 is applied to the inner wall 12 of the pipe 10. do. At this time, the size of the applicator 54 is adjusted to fit the inner diameter of the pipe 10, so that the binder 40 remains after being applied to the inner wall 12 to an appropriate thickness.

In the case of this embodiment, an end forming portion 14 is formed at the lower end of the used pipe 10 so as to reduce the diameter (see Fig. 3).

On the other hand, in the present embodiment, the method of applying the binder 40 to the inner wall of the pipe 10 is a method of using the proposed coating bar 50, in addition to this method, the binder 40 on the inner wall of the pipe 10 Can be applied as long as it can be applied. In other words, when the binder 40 flows through the pipe 10 having both ends open, the binder 40 flowing along the inner wall 12 of the pipe 10 is applied to the inner wall 12. . In addition, the binder 40 may be applied to the inner wall 12 of the pipe 10 by dipping the entire pipe 10 in a container containing the binder 40 and then removing it.

Next, the step of spraying the metal powder 32 after the binder 40 evenly applied to the inner wall 12 of the pipe 10 is performed.

The metal powder 32 is copper powder, and the size of each powder is usually between 1 μm and 800 μm in diameter. When the metal powder 32 is sprayed onto the binder 40 coated on the inner wall 12, the metal powder 32 adheres to the binder 40 having a constant viscosity, and consequently, the metal having a constant thickness on the inner wall 12. A layer of powder is formed (see FIG. 4). As mentioned above, the thickness of the metal powder 32 which adheres to the inner wall 12 can be adjusted by appropriate selection of the binder 40 which considered the viscosity.

Next, the step of sintering the metal powder 32 is performed.                     

The inner wall 12 of the pipe 10 is sintered by applying heat to the metal powder 32 having a predetermined thickness to form a sintered wick 30.

The thickness of the sintered wick 30 is preferably between about 0.1 mm and 0.5 mm. If the thickness is thinner than 0.1 mm, the movement of the working fluid may not be sufficient due to capillary action, and if it is thicker than 0.5 mm, it may not only be good for the moving fluid, but especially the inner diameter is not large enough. There is a problem that the passage for the steam flow of the pipe is not sufficiently secured.

In the present embodiment, the pipe 10 has an outer diameter of 6 mm and a thickness of 0.7 mm, in which the thickness of the sintered wick 30 is approximately 0.2 mm, the capillary phenomenon of the working fluid 20 and the internal steam flow. Considering the width of the passage, it is preferable.

In this example, the temperature for heating for sintering is between 800 ° and 1200 °. The formed sintered wick 30 has voids therein, and the void ratio represents the ratio of the volume occupied by the entire volume of the sintered wick 30. This porosity is related to the movement of the working fluid, which will be described later, by capillary action. Therefore, the temperature and time of heating for the sintering of the metal powder 32 are determined according to the kind of the metal powder 32 and the desired porosity. After the sintering ends, the lid 16 is formed by a method such as welding to block the upper end of the pipe 10 on which the sintered wick 30 is formed (see FIG. 5).

The next step is to inject the working fluid (20).

After inverting the pipe 10 in the state shown in FIG. 5, the working fluid 20 is injected into the pipe 10 through the andering forming unit 14. Then, the working fluid penetrates into the internal space of the pipe 10 or the internal void of the sintered wick 30.

As described in the related art, the working fluid 20 serves to transfer heat of a heat source to a heat sink while undergoing a phase change. As the working fluid 20, ammonia, mentanol, distilled water, sodium or lithium may be selected and used as necessary.

The next step is to vacuum seal the pipe 10.

After the working fluid 20 is injected, the air inside the pipe 10 is drawn out to create a vacuum state, and the endless forming unit 14 is welded to seal the inside of the pipe 10. 6 shows a heat pipe 1 manufactured by the heat pipe manufacturing method of the present invention.

Referring to the partially enlarged view of FIG. 6, the sintered wick 30 thinner than the thickness of the pipe 10 is uniformly formed in the heat pipe 1 according to the manufacturing method of the present invention. In addition, compared with the heat pipe manufactured by the conventional method, the thickness is not only different but also differs in the surface state of the sintered wick 30. That is, in the conventional method, the metal powder is pressed by the mandrel and sintered in the pressed state so that the surface is flat as if the cement is finished, whereas in the method of the present invention, the sintered wick 30 is made of metal It is formed by sintering after the powder has been sprayed, and the surface is naturally rough.

Since the heat transfer operation of the heat pipe 1 is the same as the conventional heat pipe described above, it is omitted. However, the difference from the heat pipe made by the conventional method is that the binder 40 is applied to the inner wall 12 of the pipe 10 and the metal powder thereon, without using the mandrel of the conventional method for forming the sintered wick. After spraying (32), the sintering method was used. The advantage is that it can solve all of the problems caused by the use of the conventional mandrel mentioned above.

That is, the workability of forming the sintered wick on the inner wall of the pipe is much better than in the prior art. Conventionally, the mandrel had to be filled with metal powder, sintered and removed the mandrel while the mandrel was put in a pipe, but since the method of the present invention does not have all of these processes, the production of heat pipes is quick and inexpensive and the quality of products This is constant.

In addition, since the sintered wick is formed on the inner wall of the pipe by applying a binder and sprinkling metal powder on the inner wall of the pipe, the thickness of the formed sintered wick is prematurely thin but uniform and uniform. Therefore, the incidence of defective products is extremely low. In addition, since the thickness of the sintered wick can be formed thinly, the width of the steam flow passage in the pipe becomes relatively wider, and heat transfer is more efficient.

In addition, although the length of a conventionally manufactured heat pipe was limited to approximately 300 mm, the method according to the present invention also allows the production of longer pipes since the use of a mandrel is not required.

On the other hand, in the case of the present embodiment, the heat pipe to be manufactured is exemplified as a straight line as in the prior art, but in the manufacturing method of the present invention, since the mandrel is not used, a curved heat pipe that is not straight is also manufactured as necessary. It is possible to do

That is, in the step of applying the binder to the inner wall of the pipe, the inner wall of the pipe is applied, not straight, by using the elastic material that can bend the rod portion of the coating rod. As described above, a method of applying an inner wall by flowing a binder into the pipe without using a coating rod may be used.

After the binder is applied, the metal powder is blown into the pipe using wind or the like, and the metal powder is sprayed onto the binder. Thereafter, sintering is performed to form a sintered wick, a working fluid is added, and a vacuum sealing step is performed to manufacture a curved heat pipe rather than a straight line.

On the other hand, in FIG. 7, the heat pipe 1a of the embodiment further includes the step of using a stopper to seal the pipe 10.

In the present embodiment, the step of applying the binder, sprinkling the metal powder and the sintering step are the same as in the above-described embodiment, but not only by welding, but also by the plug 60 to seal the pipe 10 after sintering. The difference is that the step of sealing the pipe 10 is added.

The stopper 60 has the same cross section as the pipe 10. In the case of the present embodiment, since the pipe 10 is cylindrical, its cross section is circular. Therefore, the stopper 60 is a disk having a thickness. The outer diameter of the stopper 60 is formed to be similar to the inner diameter of the pipe 10 and fitted to the pipe 10. After the plug 60 is fitted, the interface is joined by welding to seal one end of the pipe 10.

As described above, the stopper 60 may be joined by a separate welding after the sintering step. Alternatively, the stopper 60 may be inserted into one end of the pipe 10 after the step of spraying the metal powder. At the same time as the sintering process of sintering the metal powder, the stopper 60 may be bonded to the pipe 10 to be fixed. At this time, a through hole (not shown) is formed in the thickness direction in the center portion of the stopper 60 for the sintering process, and an appropriate material is coated on the outer circumferential surface of the stopper 60 so as to be fused to the pipe well. .

8 shows the heat pipe 1b of the embodiment in which the stoppers 60 and 62 are used at both ends of the pipe 10. In this embodiment, both ends of the pipe 10 are sealed by the stoppers 60 and 62 without the end forming portion.

One stopper 60 is the same as in the embodiment of FIG. 7, and the other stopper 62 is formed with a through hole 64 in the thickness direction. The through hole 64 is a hole into which a working fluid is injected after the sintering step is completed. After the working fluid is injected, the through hole 64 is sealed by a method such as welding.

In the conventional heat pipe manufacturing method, a portion which occupies only a volume but does not contribute to heat transfer has occurred at both ends of the pipe. However, the heat pipes 1a and 1b according to the present invention shown in Figs. 7 and 8 reduce these parts to one or remove both parts, thereby making various heat transfers using the heat pipes 1a and 1b. When manufacturing the device, there is an advantage that it is possible to increase the space utilization, and also to increase the heat transfer efficiency.

According to the heat pipe manufacturing method according to the present invention and the heat pipe produced by the method, the production process is simple and the production cost can be reduced, and since the sintered wick is formed using a binder without using a mandrel, The effect that it can form thinly and uniformly can be acquired.

Claims (10)

In the method of manufacturing a heat pipe comprising a pipe sealed in a vacuum state, a working fluid contained in the pipe, and a sintering wick formed by sintering metal powder on the inner wall of the pipe, An application step of applying a binder to an inner wall of the pipe; Sprinkling metal powder on a binder applied to an inner wall of the pipe; A sintering step of sintering the metal powder to form a sintered wick; An injection step of injecting a working fluid into the pipe; And a vacuum sealing step of vacuuming and sealing the pipe. The method of claim 1, Applying a binder to the inner wall of the pipe, And a coating rod having a rod portion insertable into the pipe and an application portion provided at an end portion of the rod portion to apply the binder to the inner wall of the pipe. The method of claim 1, Applying a binder to the inner wall of the pipe, Heat pipe manufacturing method, characterized in that carried out by the method of flowing a binder in a liquid state into the inside of the pipe. The method of claim 1, Heat pipe manufacturing method, characterized in that the thickness of the sintered wick is 0.1mm to 0.5mm. The method of claim 1, And a plug having a flat outer surface, the same cross-sectional shape as the pipe, and a plug fixed to the pipe, the sealing end of at least one of both ends of the pipe. The method of claim 5, The stopper is formed in the through-hole penetrating in the thickness direction, after the injection of the working fluid through the through-hole, the heat pipe manufacturing method characterized in that for sealing the pipe. The heat pipe manufactured by the method of any one of Claims 1-6. A heat pipe comprising a pipe sealed in a vacuum state, a working fluid contained in the pipe, and a sintering wick formed by sintering metal powder on an inner wall of the pipe, The sintered wick is a heat pipe, characterized in that formed by sintering after the metal powder is sprayed on the binder applied to the inner wall of the pipe. The method of claim 8, The sintered wick, the heat pipe, characterized in that the thickness of 0.1mm to 0.5mm. The method of claim 8, At least one end of both ends of the pipe, A heat pipe having a flat outer surface, the same cross-sectional shape as the pipe, and having a stopper for sealing the pipe by being fitted and fixed to the pipe.

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