Method for sealing a heat transfer unit

The present invention relates to a method for sealing a heat transfer unit, which includes the steps of providing a heat transfer unit having at least one opening, welding the opening to form a welding section and close the opening, and pinching off the welding section and cutting part of the welding section to form a cutting end and complete sealing the opening of the heat transfer unit. By means of the method of the present invention, an extremely short dead zone can be obtained and high heat conduction efficiency is enhanced, further having the effects of reducing the arrangement space and shrinking steps of the heat pipe.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a method for sealing a heat transfer unit and in particular to a method for sealing a heat transfer unit, which significantly reduces the length of the dead zone and improves heat conduction efficiency.

Description of Prior Art

With the rapid development of electronic information industry, the processing capability of the electronic device such as a CPU increasingly grows with the increasing generated heat. The heat-dissipation module combining a heat-dissipation fin and a fan has not been able to meet the requirement of heat dissipation, especially for a notebook computer. The heat pipe is a currently and commonly used device for heat transfer. The heat pipe can be considered a passive heat transfer device with high heat conductivity. Using the mechanism of two-phase heat transfer, the heat transfer capability of the heat pipe is hundreds times as large as copper having the same size. The heat pipe used as a medium of heat transfer has the advantages of fast response and small heat resistance. Therefore, the highly efficient heat-dissipation module developed from the heat pipe or its derived product is suitable to solve the heat-dissipation problems caused by high performance electronic products.

As for the traditional method for sealing a heat pipe, the heat pipe is firstly vacuumed through a pipe opening and a working liquid is filled in the heat pipe. Then, the pipe opening is stretched and shrinks to form a necking end. Next, welding (e.g., argon welding) is performed at the necking end. In this way, the necking end is sealed. However, the necking section of the traditional heat pipe cannot conduct heat, which results in a dead zone of heat transfer. The dead zone will lower heat conduction efficiency of the heat pipe (that is, poor heat conduction of the heat pipe). Also, the necking section of the heat pipe is longer, which shortens the effective heat transfer length of the heat pipe such that when the heat pipe is installed in a smart mobile device such as a smart watch, a smart phone, or a wearable device, the occupied space of the heat pipe will make the assembly of the smart mobile device difficult, which is unfavorable to the shrinking of the smart mobile device.

Therefore, how to overcome the above problems and disadvantages is the focus which the inventor and the related manufacturers in this industry have been devoting themselves to.

SUMMARY OF THE INVENTION

Thus, to effectively overcome the above problems, the primary objective of the present invention is to provide a method for sealing a heat transfer unit, which can effectively reduce the length of the dead zone and improves heat conduction efficiency

Another objective of the present invention is to provide a method for sealing a heat transfer unit, which can effectively reduce the arrangement space when the sealed heat pipe is used.

Yet another objective of the present invention is to provide a method for sealing a heat transfer unit, which can reduce the shrinking steps of the heat pipe.

To achieve the above objectives, the present invention provides a method for sealing a heat transfer unit, which includes the steps of (a) to (c). Step (a) provides a heat transfer unit having a chamber and forming at least one opening, wherein an inner wall of the chamber forms at least one wick structure, wherein a working fluid is filled in the chamber; Step (b) welds the opening to form a welding section and close the opening; and Step (c) pinches off the welding section and cuts part of the welding section to form a cutting end and complete sealing the opening of the heat transfer unit. By means of the method of the present invention, an extremely short dead zone can be obtained and high heat conduction efficiency is enhanced, further having the effects of reducing the arrangement space and shrinking steps of the heat pipe.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is to provides a method of removing the dead zone of a flat heat pipe. Please refer toFIG. 1, which is a flow chart of the method for sealing a heat transfer unit according to the first embodiment of the present invention. Please also refer toFIGS. 2A, 2B, 2C, 2D, and 3. In the current embodiment, a cylindrical heat pipe is used as an example of the heat transfer unit1for explanation. The method for sealing a heat transfer unit includes the following steps.

Step (100): providing a heat transfer unit having a chamber and forming at least one opening, wherein an inner wall of the chamber forms at least one wick structure, wherein a working fluid is filled in the chamber.

The heat transfer unit1which is a cylindrical heat pipe is provided. The heat transfer unit1has a chamber11therein; each of two ends of the heat transfer unit1has an opening12communicating with the chamber11. An inner wall of the chamber11forms at least one wick structure13. In the current embodiment, sintered powder is used as an example of the wick structure13for explanation, but not limited to this. In practice, the wick structure13may be grooves, a metal net, or a fiber net. A working fluid14(e.g., pure water, inorganic compound, alcohols, ketones, liquid metal, coolant, or organic compound) is filled in the chamber11. Two dead zones15are individually defined between the wick structure13and each of the two opposite openings12at two ends of the heat transfer unit1. The wick structure13is not formed in the dead zones15, which helps the working fluid14be filled into the chamber11. Therefore, the dead zones15of the heat transfer unit1cannot be used for heat transfer.

Step (101): welding the opening to form a welding section and close the opening.

Two openings12at two ends of the heat transfer unit1have the dead zones15. In the current embodiment, the dead zones15are the portions which cannot carry out heat transfer on the heat transfer unit1and in which the wick structure13is not formed. Ultrasonic welding is performed on the dead zones15via ultrasonic welding equipment5. The inner wall in the portion of welding is welded and closed. Also, a certain range of the inner wall is required to be closed during the ultrasonic welding. Thus, after the ultrasonic welding is performed on two openings12of the heat transfer unit1, two welding sections2will be produced individually to close the individual openings12. Besides, the chamber11is vacuumed during the closing process to become a vacuumed chamber11.

Step (102): pinching off the welding section and cutting off part of the welding section to form a cutting end and complete sealing the opening of the heat transfer unit.

After the ultrasonic welding is performed, two ends of the heat transfer unit1individually form the welding section2. Besides, a certain range of the welding section2is required to be closed during the welding. Therefore, the pinch-off equipment6is used to pinch off the welding section2and cut off part of the welding section2. At the pinch-off location of the welding section2, the pinch-off equipment6closes the welding section2again to form a cutting end3such that the welding section2and the cutting end3can be closed effectively and thus the heat transfer unit1is sealed.

Therefore, the design of the present invention can be directly applied in a common finished heat transfer unit1, such as the above-mentioned cylindrical heat pipe, the flat heat pipe, the heat conducting plate or vapor chamber formed by an upper plate and an lower plate stacked to each other, to reduce the length of the dead zone15and minimize the area disposed by the dead zone15. As a result, the heat conduction efficiency of the heat transfer unit1can be relatively improved. (That is, the heat transfer unit1is almost the effective area.). In addition, after the dead zone15is effectively reduced by means of the design of the present invention, the whole length of the heat transfer unit1can be effectively reduced, resulting in a heat transfer unit1with a short and small size. In this way, when the heat transfer unit1of the present invention is applied in a smart mobile device such as a smart watch, smart phone, or wearable device, it occupies little space and has a space saving effect, facilitating size reduction of smart mobile devices.

Please also refer toFIGS. 1, 4A, 4B, 4C, 4D, and 5, which are flow charts of a method for sealing a heat transfer unit according to the second preferred embodiment of the present invention. The current embodiment uses a flat heat pipe for explanation, instead of a cylindrical heat pipe as the heat transfer unit1of the first embodiment. In the current embodiment, the method for sealing a heat transfer unit mainly includes the following steps. First, a heat transfer unit1is provided, which is a finished product of the flat-pressed heat pipe. The heat transfer unit1has a chamber11therein; each of two ends of the heat transfer unit1has an opening12. The inner wall of the chamber11forms the wick structure13; the working fluid14is filled in the chamber11. Two dead zones15are individually defined between the wick structure13of an inner wall of the heat transfer unit1and each of the two opposite openings12at two ends of the heat transfer unit1. Then, the two ends of the heat transfer unit1form the welding sections2after the ultrasonic welding is performed. Next, the welding sections2are pinched off using the pinch-off equipment6and part of the welding sections2are cut off. At the pinch-off location of the welding section2, the pinch-off equipment6closes the welding section2again to form a cutting end3such that the welding section2and the cutting end3can be closed effectively and thus the heat transfer unit1is sealed. In the way, after the dead zone15is effectively reduced by means of the design of the present invention, the whole length of the heat transfer unit1can be effectively reduced, resulting in a heat transfer unit1with a short and small size. Therefore, when the heat transfer unit1of the present invention is applied in a smart mobile device such as a smart watch, smart phone, or wearable device, it occupies little space and has a space saving effect, facilitating size reduction of smart mobile devices.

Please refer toFIGS. 1, 6A, 6B, 6C, 6D, and 7, which are flow charts of a method for sealing a heat transfer unit according to the third preferred embodiment of the present invention. The current embodiment uses a flat vapor chamber formed by an upper plate and a lower plate stacked to each other as an example of the heat transfer unit1for explanation, instead of the heat transfer unit1of the first embodiment. In the current embodiment, the method for sealing a heat transfer unit mainly includes the following steps. First, a heat transfer unit1is provided, which is a flat vapor chamber. The heat transfer unit1has a chamber11therein and a filling section4at one end thereof. An opening12is formed in the filling section4. The inner wall of the chamber11is provided with the wick structure13; the working fluid14is filled in the chamber11. The wick structure13is not disposed in the filling section4and thus the filling section4is a dead zone15in the current embodiment. Next, the filling section4of the heat transfer unit1is welded by the ultrasonic welding to form a welding section2. The welding sections2are pinched off using the pinch-off equipment6and part of the welding sections2are cut off. At the pinch-off location of the welding section2, the pinch-off equipment6closes the welding section2again to form a cutting end3such that the welding section2and the cutting end3can be closed effectively and thus the heat transfer unit1is sealed. In the way, after the dead zone15is effectively reduced by means of the design of the present invention, the whole length of the heat transfer unit1can be effectively reduced, resulting in a heat transfer unit1with a short and small size. Thus, when the heat transfer unit1of the present invention is applied in a smart mobile device such as a smart watch, smart phone, wearable device, or tablet computer, it occupies little space and has a space saving effect, facilitating size reduction of smart mobile devices.

In summary, compared with the traditional method, the present invention has the following advantages.

1. The length of the dead zone can be reduced.

2. The heat conduction efficiency of the heat transfer unit can be improved.

3. The space is saved.

The above-mentioned embodiments are only the preferred ones of the present invention. All variations regarding the above method, shape, structure, and device according to the claimed scope of the present invention should be embraced by the scope of the appended claims of the present invention.