KR100604234B1 - Appatatus for filling working fluid in heat pipe - Google Patents

Abstract

The present invention is a steam injection step of injecting operating steam from the lower end of the body of the heat pipe is closed and the bottom open, a blow to open the top of the heat pipe to discharge the mixed gas of air gas and steam Step (blow step), a working fluid's steam filling step of filling the operating steam inside the heat pipe by closing the upper end when the discharge of the mixed gas is completed, and a seal closing the bottom of the body of the heat pipe Disclosed is a working fluid filling method for a heat pipe including a sealing step and a filling device therefor.

Heat pipe

Description

APPLICATION FOR FILLING WORKING FLUID IN HEAT PIPE

1 is a block diagram of a general heat pipe.

2 is a view for explaining a conventional steam blow process.

3 is a view showing a working fluid filling apparatus of a heat pipe according to the present invention.

4 is an explanatory view of a working fluid filling method of a heat pipe according to the present invention;

5 is a block diagram of a working fluid filling method of a heat pipe according to the present invention.

Figure 6 is a block diagram relating to the operating steam filling process of the pressure vessel according to the present invention.

7 is a graph showing the characteristics of the working fluid filling method according to the present invention.

The present invention relates to a working fluid filling apparatus of a heat pipe, and more particularly to a working fluid filling apparatus of a heat pipe capable of filling a working fluid in a small diameter small heat pipe.

In recent years, the trend toward higher density packaging of components and systems has become a common phenomenon throughout the electronics industry, including electronics / communication devices, and heat dissipation and cooling of systems are also becoming more serious. When the generated heat of electronic equipment is neglected, it is a major cause of deterioration of the performance of equipment and system and reduction of lifespan. Therefore, a cooling method is required to dissipate effectively. The size of the cooling device is also to be able to be formed in a fine size.

As a cooling technology for dissipating heat generated in electronic equipment, a heat sink or a fan is attached to the heat sink. However, when the size of the heat sink decreases, Not only does the heat dissipation rate decrease relatively with the decrease, but there is a limitation in producing a fan with a small size and a limitation of noise generation. In recent years, a cooling method using a heat pipe as a method to replace the fan has been discussed. It is becoming.

The heat pipe is a heat exchanger that effectively transfers heat without a force even at a small temperature difference by using latent heat of evaporation of a working fluid therein, and FIG. 1 illustrates the operation principle of this general heat pipe.

The pipe body 101 of the heat pipe is largely divided into an evaporation unit 102 (heat absorption unit), a transfer unit 103 (heat insulation unit), a condensation unit 104, a heat radiation unit, and operates in the evaporation unit 102 where the heat source is located. The fluid absorbs heat, diffuses into the pipe body in a vapor state, and passes heat through the transfer part 103 to release heat from the condensation part 104. The working fluid which has released the heat from the condensation unit 104 is condensed and then becomes a liquid and returns to the evaporation unit 102 on the wall of the wick 105 of the pipe body. The working fluid transfers heat in the heat pipe by successively repeating condensation and evaporation. The evaporation unit 102 and the transfer unit 103 have a higher temperature than the condensation unit 104, and the vapor pressure in each portion becomes saturated, and the relationship between the vapor pressures is that the pressure between the evaporator 102 and the transfer unit 103 is the condensation unit. Higher than As a result of this, the vapor is transferred from the evaporator to the condenser 104 via the conveyer 103. This happens very quickly because the heat transfer rate is close to the speed of sound.

The performance of this type of heat pipe can be affected by various variables such as the wick structure circulating the working fluid, the type and filling amount of the working fluid, the vacuum and cleanliness of the pipe body, and especially the heat pipe. Due to the miniaturization, the filling of the working fluid is an important problem in the heat pipe manufacturing process.

2 is a view for explaining a steam blow process which is a working fluid filling process of a conventional heat pipe.

Referring to the drawings, first the working fluid is injected into the heat pipe body and then sealed (a). The sealed pipe body is heated, and in this case, the mixed gas is formed in the heat pipe when the air gas (including inert gas such as air or argon gas) and steam filled in the heat pipe before sealing are mixed. (B). At this time, when the opening is opened to one end of the heat pipe, the mixed gas in which the impurities are collected by the internal and external pressure difference is blown away, and only the low density hot steam gas is left inside (c). When the opening is sealed after a predetermined time, the low-density hot steam gas is cooled and fluidized to obtain a vacuum filled with a predetermined amount of working fluid inside the pipe body (d).

However, such a conventional steam blow process has a disadvantage in that it cannot be applied to a micro heat pipe (MPH) or a flat plate micro heat pipe (FPMPH) having a small diameter. In the case of a micro heat pipe with a small diameter, not only is it difficult to inject the working fluid, but also when the opening is opened after heating even if the working fluid is injected (see FIG. By flying away it is almost impossible to fill a certain amount of working fluid inside.

In particular, Korean Patent Laid-Open Publication No. 2003-0053424 discloses a fine heat pipe having a cross section of a polygonal structure using an extrusion and drawing process, wherein the fine heat pipe is formed by capillary forces generated at each capillary portion of the polygonal structure. By allowing the working fluid to flow, it is possible to miniaturize the heat pipe. That is, the conventional heat pipe is a wick structure for circulating the working fluid, which is used by a mesh type that produces a wick structure through a copper mesh or a sintered type that produces a wick structure by sintering fine copper particles. Conventional heat pipes have to be provided with such a wick structure inside the pipe body, there is a certain limit in reducing the diameter.

However, since the edges of the polygonal structures replace the wick structures, the fine heat pipes can make the heat pipes having a wickless type wick structure smaller than 3 mm in diameter. However, in the case of such a fine heat pipe, it is impossible to fill the working fluid by the conventional steam blow process as described above, and a method using a vacuum pump and a syringe has been proposed.

In the vacuum pump and syringe method, the vacuum pump is connected to the fine heat pipe and the inside is vacuumed to inject the working fluid into the pipe by the suction force of the vacuum. Afterwards, the remaining working fluid is frozen using liquid nitrogen. Thereafter, the inside of the pipe is evacuated again using a vacuum pump. At this time, since the working fluid inside is frozen, only the space inside the pipe is evacuated without being accompanied by the suction pressure of the vacuum pump. Then, when the opening of the pipe is sealed, the inside of the pipe is in a vacuum state filled with a predetermined amount of working fluid.

However, this method is not only complicated in the process including cooling and removing a part of the working fluid injected using a syringe, but also has a disadvantage in that it is difficult to leave an appropriate amount of working fluid in consideration of the diameter of the syringe needle. have. There is also the possibility that some losses will occur when the vacuum is used to vacuum the interior, leaving only a frozen working fluid.

The present invention has been made to solve the above problems, an object of the present invention is to provide a working fluid filling apparatus of a heat pipe capable of filling the working fluid in a small diameter small heat pipe.

An object of the present invention, the steam injection step of injecting the operating steam from the bottom of the body of the heat pipe is closed and the bottom open, the upper end of the heat pipe, the mixed gas of air gas and steam Blowing step (blow step), the working fluid's steam filling step for filling the operating steam in the heat pipe by closing the top when the discharge of the mixed gas is completed, and the body of the heat pipe It is achieved by a method of filling a working fluid of a heat pipe comprising a sealing step of closing the bottom.

Another object of the present invention, the working fluid and the working fluid is formed by vaporizing the working fluid therein, the opening is formed so that the working vapor can communicate with the outside, is attached to the opening side to operate through the opening A pressure vessel for opening and closing the control of the communication of steam, a connection tube for connecting the opening of the pressure vessel and the inside of the body of the heat pipe to communicate with the steam, and a heating coil capable of heating the pressure vessel in an overheating state It is achieved by the working fluid filling device of the heat pipe.

The heat pipe uses latent heat of evaporation of the working fluid inside to transfer heat without power even at a small temperature difference. Therefore, the performance of the heat pipe is greatly influenced by the filling of the working fluid. That is, precise injection of working fluid, filling amount of working fluid, internal vacuum degree and chemical reactivity of working fluid and heat pipe are important.

When there is chemical reactivity between the heat pipe material and the working fluid, even when the working fluid is filled while maintaining a constant vacuum degree, the working fluid circulates inside to generate an inert gas by reacting with the heat pipe, and the inert gas circulates in the working fluid. Interfere with this and cause performance degradation and lifespan. Therefore, the heat pipe and the working fluid need to be matched with materials that are not chemically reactive with each other. In general, when the heat pipe is made of copper, the working fluid is pure water, and when it is made of aluminum, the working fluid is acetone.

On the other hand, in relation to working fluid injection, the present invention uses steam injection to enable working fluid injection even inside a heat pipe having a diameter of 3 mm or less. This steam injection process takes advantage of the property that the volume of the fluid is greatly increased when it is vaporized, the gas increases in density as the pressure increases under the same temperature, and the different gases are uniformly mixed with each other under normal conditions.

According to the present invention, the operating steam is injected into the heat pipe by steam injection, and thus the working steam can be injected into the fine heat pipe having a diameter of 1.5 mm to 3.0 mm. The mixture is uniformly mixed with the air gas and the inert gas and discharged to the outside in a state in which these gases are collected, and the heat pipe is sealed with only pure operating steam filled therein. The working steam fills the inside of the heat pipe in a vapor state, but when cooled, the volume is greatly reduced, and the space other than the space occupied by the working fluid remains in a vacuum state. That is, the steam injection process according to the present invention makes it possible to achieve the degree of vacuum and the working fluid filling inside the heat pipe.

In addition, the present invention utilizes the property that the same gas is constantly changed according to three values of pressure, temperature and volume and one physical value depends on the other. Therefore, it is possible to control the pressure by appropriately controlling the temperature in the volume condition. In addition, once the pressure, temperature and volume values are determined, in an ideal state it is possible to determine the mole amount of the filling gas by PV = nRT, and finally the filling amount of the working fluid can be determined accurately. Of course, the high temperature steam gas has similar characteristics to the ideal gas, but may have a constant correction value by an equation determined experimentally. The experimentally determined correction value depends on the capacity characteristics of the equipment and depends on the equipment characteristics and is determined experimentally.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a working fluid filling apparatus of a heat pipe according to the present invention, Figure 4 is a view for explaining a working fluid filling method of a heat pipe according to the present invention, Figure 5 is a heat pipe according to the present invention 6 is a block diagram illustrating a method of filling a working fluid, and FIG. 6 is a block diagram illustrating a process of preparing working steam in a pressure vessel according to the present invention.

Referring to FIG. 3, the heat pipe filling apparatus according to the present invention includes a pressure vessel 10, a connection tube 20, and a heating coil 30.

The pressure vessel 10 according to the present invention is provided with an opening 12 in which the working fluid and the working fluid formed by vaporizing the working fluid are accommodated therein and the working steam is movable. On the side of this opening 12, a control valve 15 for controlling the communication of the fluid through the opening is attached.

According to the present invention, the opening 12 is equipped with a connection tube 20 connecting the heat pipe 1 and the opening 12 of the pressure vessel 10. The connection tube 20 is configured to fit the heat pipe 10 into one end when a fill tube is used. That is, one end of the fill tube 20 is fitted into the opening of the pressure vessel 10 and the other end is fitted to the lower end of the heat pipe 1.

The working fluid contained in the pressure vessel 10 is a working fluid filled in the heat pipe. Therefore, water is used when the heat pipe 1 is made of copper, and acetone is used when it is made of aluminum.

Since the pressure vessel 10 supplies the working fluid inside the heat pipe 1, the working steam filled in the pressure vessel 10 should not include an inert gas. Therefore, the pressure vessel 10 is made of a material that does not generate an inert gas by chemically reacting with the working fluid, and considering that the working fluid is commercially water or acetone, the pressure vessel 10 is preferably made of stainless steel Do.

The present invention includes a heating coil 30 for heating the pressure vessel (10). The heating coil may be installed integrally with the pressure vessel 10 so as to heat the pressure vessel 10. The heating coil 30 can control the amount of heat generated to maintain the inside of the pressure vessel 10 at the required temperature.

According to a preferred embodiment of the present invention, the pressure sensor 10 further includes a temperature sensor 40 for sensing a temperature and a pressure sensor 50 for sensing pressure. The temperature sensor 40 and the pressure sensor 50 have display parts 45 and 55 displaying the sensing value. The operator determines the temperature inside the pressure vessel 10 through the temperature sensor 40 to control the amount of heat so that the heating coil 30 heats the pressure vessel 10 in an overheating state, and the inside of the pressure vessel 10 The amount of heat generated can be controlled so that the temperature is kept constant.

According to the present invention, the heating coil 30 may be connected to a watt meter (62) and the slits (64, slidacs) for the heating value control. The wattmeter 62 makes it possible to check the power consumed by the heating coil 30, and the slide 64 is a device that directly adjusts the power applied to the heating coil 30. Therefore, the operator can maintain the temperature inside the pressure vessel 10 at the required temperature by adjusting the slidance 64 while watching the watt meter 62 and the displayed value.

Preferably, the apparatus of the present invention may be configured to include a controller (not shown) so that the operation of the apparatus to be described below is automatically controlled.

4 to 6, the operation of the apparatus of the present invention and the working fluid filling method of the heat pipe according to the present invention will be described.

The working fluid filling method of the heat pipe according to the present invention includes a steam injection step (S30), a blow (Slow) step (S40), a working steam filling step (S50), and a sealing step (S60) do. Preferably, the operation steam injection of the steam injection step (S30) is made after the pressure vessel connection step (S10) and the fluid communication step (S20), the pressure vessel (10) connected in the pressure vessel connection step (S10) is operated. Fluid injection step (S110), mixed gas filling step (S120), mixed gas discharge step (S130), and operating steam filling step (S140) is performed to fill the working steam inside.

In the steam injection step (S30) according to the invention the operating steam is supplied from the lower end of the body of the heat pipe 1 is injected into the operating steam inside the body of the heat pipe (1). Working steam means the working fluid is vaporized.

According to the invention the working steam is provided from the pressure vessel 10. Referring to Figure 6 describes the process of filling the working vessel in the pressure vessel 10 as follows.

First, a working fluid is injected into the pressure vessel 10 (S110).

After the injection of the working fluid, the control valve 15 located at the opening 12 side of the pressure vessel 10 is closed, and fluid communication is blocked to separate the inside and the outside of the pressure vessel 10. Subsequently, the inside of the pressure vessel 10 is heated while the slide duct 64 is adjusted to supply power to the heating coil 30. At this time, the temperature to be heated is heated to the over heating (over heating) temperature above the vaporization point, but if the working fluid is water is heated to about 110 ℃ ~ 130 ℃.

Then the mixed gas filling step (S120) is performed.

The working fluid is heated to vaporize the working steam, the pressure vessel 10 inside the pressure gradually increases by the working steam. When the fluid is vaporized, its volume increases very much, and the gas increases its density when the pressure increases under the same temperature, so that the inside of the pressure vessel 10 has a high temperature and high temperature due to the continuously supplied working steam. It is in a state. At this time, since the gases are uniformly mixed with each other, the working vapor collects the air gas existing in the pressure vessel 10 and the inert gas in the pressure vessel 10 to form a mixed gas phase while uniformly mixing. That is, the mixed gas is filled in the pressure vessel 10 in a high temperature and high density state.

Subsequently, the mixed gas discharge step S130 is performed.

When the control valve 15 is opened to open the opening 12 of the pressure vessel 10, the mixed gas is discharged to the outside of the pressure vessel 10 due to the pressure difference. Since the inside of the pressure vessel 10 is an overheating state, the operating steam is continuously supplied from the working fluid of the lower surface, and the pressure inside the pressure vessel 10 is lowered by the opening 12, but is still higher than the outside. The outside air gas is not introduced into the pressure vessel 10, only the outflow is made inside the pressure vessel 10 is filled with only the working steam.

Subsequently, as the operating steam filling step (S140), when it is determined that the mixed gas inside the pressure vessel 10 is completely discharged in the mixed gas discharge step, the control valve 15 is closed to close the opening 12, and the lower surface is operated. Only the pure working steam supplied from the fluid is filled in the container 10.

At this time, it is preferable to maintain a constant heating value so that the pressure vessel 10 is filled with operating steam at a constant temperature and pressure. In the pressure vessel 10, the volume is determined by the pressure vessel 10 used, and the temperature and pressure change while having a correlation with each other, so that if the temperature is properly controlled through the calorific value of the heating coil, the inside of the pressure vessel 10 It is possible to charge working steam at a constant pressure.

Referring back to FIG. 5, when the pressure vessel 10 is filled with the working steam as described above, the pressure vessel connection step S10 for connecting the opening of the pressure vessel 10 to the lower end of the heat pipe with the fill tube 20 is performed. Is performed. At this time, the lower end of the heat pipe 1 is an open state, that is, an open state, and the upper end is a closing state, that is, a closed state.

In general, the closing of the heat pipe 1 is performed by cool welding by pinch off. The bonding method by the pinch-off is generally called cool welding. When the heat pipe 10 is picked up using forceps, it means a phenomenon in which line contact occurs while being bent due to pressure and sticks to each other. Bonding is performed only by pressurization at room temperature, not heating, so it is called cool welding. Ductile materials such as copper or aluminum are reliably joined so that closing, ie, fluid communication, is prevented even by cool welding by pinch-off. Of course, in the present invention, the closing may be implemented by other methods, and the process itself for joining one end to block fluid communication is referred to as closing.

On the other hand, when opening the heat pipe closed by the pinch-off can be used to cut the cool welding surface using a high speed cutter or to use the forceps to straighten the bent portion.

When the heat pipe is connected to the pressure vessel 10, and then in the fluid communication step (S20), the control valve 15 is opened to open the inside of the body and the pressure vessel 10 of the heat pipe 1, the upper end of which is closed. Fluid communication. By the fluid communication, the working steam inside the pressure vessel 10 is injected into the heat pipe 1 while being injected by the pressure difference.

In the steam injection step (S30) in which the operating steam is injected into the heat pipe, while the operating steam is supplied into the heat pipe, the operating steam collects air gas in the heat pipe 1 to form a mixed gas phase, and heat The inside of the pipe 1 achieves a high temperature and high density state.

Then, as the blow step (S40), the upper end of the heat pipe (1) is opened and the mixed gas of air gas and working steam filled in the heat pipe (1) by the pressure difference is blown through the upper end off. At this time, the operating steam in the pressure vessel 10 is continuously supplied from the bottom of the heat pipe (1) body.

Subsequently, as the operation steam filling step (S50), when the discharge of the mixed gas inside the heat pipe 1 is completed, the upper end of the heat pipe is closed again and the operating steam is filled therein. Although the pressure inside the pressure vessel 10 is slightly lowered through opening of the upper end of the heat pipe 1, when the heat generation amount of the heating coil 30 is constantly controlled, the temperature and pressure inside the pressure vessel 10 are kept constant. It is possible to be. That is, since the inside of the pressure vessel 10 and the heat pipe 1 is in a state in which the movement of the working steam is freely communicated with each other, the inside of the pressure vessel 10 and the heat pipe 1 are in the same temperature and pressure state. When the inside of the pressure vessel 10 is maintained at a constant temperature and pressure through the heating coil, the heat pipe 1 is also filled at a constant temperature and pressure. Since the working steam amount of the heat pipe 1 is affected by temperature and pressure, if the working steam inside the heat pipe is filled at a constant temperature and pressure in the mass production process, this means that the working fluid amount is constantly filled.

On the other hand, according to the present invention, it is possible to precisely determine the amount of working fluid in the heat pipe 1. That is, under the condition equation, the volume is a condition given by the heat pipe 1, and the temperature and pressure are changing while having a correlation with each other. Therefore, if the temperature is appropriately adjusted through the calorific value of the heating coil 30, it is possible to appropriately control the pressure inside. By controlling P and T simultaneously under the condition n = PV / RT, it is possible to determine the molar amount of the working fluid filled in the heat pipe 1, which means that the working fluid amount can be determined.

After the filling of the working steam as a sealing step (S60), by closing the bottom of the body of the heat pipe (1) the heat pipe seals the interior of the filled state only a certain amount of working steam.

When the heat pipe cools at room temperature, the working steam is fluidized in a reduced volume state, and the remaining space becomes a vacuum state (S70). In other words, the vibration and the working fluid filling can be achieved at the same time.

7 is a graph showing the characteristics of the working fluid filling method according to the present invention.

Referring to FIG. 7, it can be seen that the working fluid can be injected into the fine heat pipe very precisely according to the change of the temperature and the pressure variable of the pressure vessel. In particular, in contrast to the method using a vacuum pump and a syringe which is one of the working fluid filling method of the fine heat pipe, in the above method, the controlled working fluid filling amount is the solution filling amount before the vacuuming step, so that the vacuum pumping step Although it is difficult to inject a partly variable and precisely controlled working fluid, it can be seen that the present invention can directly fill a more precise working fluid by directly controlling the actual injection amount.

The present invention fills a predetermined amount of solution for each heat pipe and heats it again to remove the degassing process or re-vacuum treatment after rapid cooling, and the working fluid of the heat pipe continuously after filling the pressure vessel 10 with working steam. Filling is possible, which improves continuous productivity. Further, according to the present invention, it is possible to constantly control the amount of working fluid filled in the heat pipe.

Moreover, the present invention enables the working fluid to be filled in the fine heat pipe by allowing the working steam to be naturally transferred into the heat pipe using the pressure difference through steam injection.

Claims (8)

delete delete delete delete delete delete The operating fluid and the working fluid is vaporized to receive the working vapor formed therein, the opening is formed so that the working vapor can communicate with the outside, attached to the opening side to open and control the communication of the working steam through the opening Pressure vessel; A connection tube connecting the opening of the pressure vessel and the inside of the body of the heat pipe to allow the working steam to communicate; A heating coil capable of heating the pressure vessel in an overheating state; And Including a temperature sensor for sensing the temperature inside the pressure vessel, And a heat generating amount of the heating coil is adjustable so that the temperature inside the pressure vessel recognized by the temperature sensor can maintain a required value. The method of claim 7, wherein The working fluid filling apparatus of the heat pipe further comprises a pressure sensor for sensing the pressure inside the pressure vessel.

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