Method for fabricating wick microstructures in heat pipes

Abstract

The invention provides a method for fabricating wick microstructures in heat pipes, comprising the following steps: providing a flat plate and a mold with several molding holes; filling a dry powder material in the several molding holes and putting the mold to cover the flat plate so as to form an object to be sintered; sintering the object; and removing the mold to form a flat plate with wick microstructures. The wick microstructures are arranged on the flat plate in a form of microgrooves, microcylinders or any combination of them. The flat plate with wick microstructures is further processed to form a heat pipe with a characteristic shape and having two kinds of wick microstructures such that the heat transferred by the heat pipe is increased and the occurrence of dry out of the heat pipe is delayed.

Description

CROSS REFERENCE TO RELATED DOCUMENT[0001]This application is a continuation-in-part of U.S. patent application Ser. No. 11 / 132,220 filed on May 19, 2005 for Method For Fabricating Wick Microstructures in Heat Pipes”.FIELD OF THE INVENTION[0002]The present invention relates to a method for fabricating wick microstructures in heat pipes, more particularly to a method for fabricating wick microstructures in heat pipes, in which the wick microstructures are arranged in any size on any area of inner surface of heat pipes by sintering.BACKGROUND OF THE INVENTION[0003]As time goes by, heat generated in each unit electronic component is increasing. Besides, miniaturizing of electronic packages and integrating more functions into a microsystem are occurring simultaneously. Thus, the density of giving out heat in electronic components is higher and higher such that thermal management is more and more difficult. If thermal management of an electronic system is not good, increased junction temp...

AI Technical Summary

Benefits of technology

[0009]The primary objective of the present invention is to provide a method for fabricating wick microstructures in heat pipes, which utilizes sintering and processing a flat plate to form two wick microstructures such that the heat transferred is increased.

[0010]The secondary objective of the present invention is to provide a method for fabricating wick microstructures in heat pipes, in which a mold with several molding holes is utilized to control arrangements and sizes of the sintered microstructures on the surfaces of heat pipes such that the heat transferred is increased.

[0011]Another objective of the present invention is to provide a method for fabricating wick microstructures in heat pipes, in which a mold with several molding holes is utilized to control arrangements and sizes of the sintered microstructures on the surfaces of heat pipes such that the occurrence of dry out of heat pipes is delayed.

[0012]To achieve the foregoing objectives, the present invention provides a method for fabricating wick microstructures in heat pipes, comprising the following steps: providing a flat plate and a mold with several molding holes; filling a dry powder material in the several molding holes and putting the mold to cover the flat plate so as to form an object to be sintered; sintering the object; and removing the mold to form a flat plate with wick microstructures. The wick microstructures are arranged on the flat plate in a form of microgrooves, microcylinders or any combination of them. The flat plate with wick microstructures is further processed to form a heat pipe with a characteristic shape and having two kinds of wick microstructures such that the heat transferred by the heat pipe is increased and the occurrence of dry out of the heat pipe is delayed.

[0014]To make the examiner easier to understand the objectives, structure, innovative features, and function of the invention, preferred embodiments together with accompanying drawings are illustrated for the detailed descriptions of the invention.

Problems solved by technology

Thus, the density of giving out heat in electronic components is higher and higher such that thermal management is more and more difficult.

If thermal management of an electronic system is not good, increased junction temperature will cause decreased clock speed and operation efficiency, even a shortened usage life of the electronic component.

Therefore, thermal management of electronic components is becoming a key issue concerned by electronic product manufacturers.

In addition, when heat given out by electronic components such as CPU of a personal computer is increased, a difficult problem of heat being not uniformly given out is accompanied simultaneously thus hot spots will be formed on surfaces of the electronic components.

(1) sintered wick structures: (a) U.S. Pat. No. 4,274,479 disclosing wick structures in heat pipes by using sintered grooves, wherein the grooves may be made in any desired crossectional configuration. Thus, the wick structures on inner surface of the heat pipe are in the shapes of groove or others and are longitudinally extended along the heat pipe. Besides, the bottom of each groove forms a continuous layer for providing lateral flowing passage for working fluids. However, the bottoms of the sintered wick structures are connected to form a continuous layer so that it will form an obstacle when boiling bubbles escape.

(b) U.S. Pat. No. 5,076,352 disclosing a capillary structure formed of at least two layers of perforated material separated by granules of powdered material so as to increase permeability of the wick structure.

(2) grooved wick structures: Taiwan Patent Publication No. 528,151 disclosing a multiple-layer wick structure comprising an externally sealed container and an inner container in heat pipes, wherein grooves are arranged around the containers to form the wick structure.

Although grooved wick structures operate horizontally can remove huge heat, the heat removed will decreases rapidly once a tilting angle occurs when the heat pipe operates because the capillary pumping of grooved wick structures is not strong.

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