WO2008100007A1

WO2008100007A1 - Flat plate heat pipe and method for manufacturing the same

Info

Publication number: WO2008100007A1
Application number: PCT/KR2007/006280
Authority: WO
Inventors: Yong-Duck Lee; Hyun-Tae Kim; Hyuck-Jin Kwon; Su-Hyeon Kim; Hwan-Hee Oh
Original assignee: LS Cable Ltd; LS Mtron Ltd
Current assignee: LS Mtron Ltd; LS Cable and Systems Ltd
Priority date: 2007-02-16
Filing date: 2007-12-05
Publication date: 2008-08-21
Anticipated expiration: 2009-08-16
Also published as: KR20080076423A; TW200835898A

Abstract

A flat plate heat pipe includes a flat plate case having a plurality of grooves formed in an inner side thereof and having a successive circumferential surface such that both ends thereof are finally sealed with a coolant being injected into an inner space thereof; and a screen mesh put into the inner space of the flat plate case.

Description

FLAT PLATE HEAT PIPE AND METHOD FOR MANUFACTURING THE SAME

Technical Field

[1] The present invention relates to a flat plate heat pipe and a method for manufacturing the same, and more particularly to a flat plate heat pipe having a non-joining flat plate case and a method for manufacturing the same. Background Art

[2] Various electronic devices suffer from heat generated from inner electronic parts therein in operation. To efficiently emit out the heat, a predetermined flat plate heat transfer device is preferably attached to a corresponding heat source such that the heat is transferred to a heat emitting unit such as a heat sink.

[3] Generally, a flat plate heat transfer device is configured such that a coolant is filled in a sealed metal case with a small thickness, and a wick structure is formed on an inner side of the metal case. Thus, heat generated from a heat source is transferred to the wick structure contacting with the heat source, and in this region, a coolant contained in the wick structure is evaporated and diffused in all directions through an inner space of the metal case. Then, the coolant is condensed after emitting heat at the wick structure in a cooling area where the heat sink is installed. The heat emitted during the condensation process is transferred to the heat sink, and then emitted out in a forced convection manner using a cooling fan.

[4] According to the flat plate heat transfer device configured as mentioned above, a coolant in a liquid state absorbs heat from a heat source and is then evaporated, and the evaporated vapor should be moved again to the cooling area, so a space for flowing the vapor should be ensured. However, it is not easy to form such a vapor diffusion channel in the flat plate heat transfer device with a small thickness. In particular, since the inside of the case of the flat plate heat transfer device is kept in vacuum (or, in a decompressed state), upper and lower plates of the case may be crushed or distorted during a manufacture process, which deteriorates reliability of a product.

[5] Meanwhile, in a conventional flat plate heat transfer device, upper and lower cases are joined to form the flat plate case, as disclosed in Korean Patent Registration No. 495,699 (entitled as a flat plate heat transfer device and its manufacturing method). However, this method has drawbacks since the joining process of the upper and lower cases is not easy and consumes much cost, thereby increasing a product price.

[6] As an alternative, a flat plate heat pipe that forms a flat plate case by compressing a pipe is also suggested. However, such a conventional heat pipe is insufficient for giving a satisfactory wick structure, not easy for manufacture of a flat plate heat pipe with a small thickness, and difficult to keep its shape since a deforming force occurs in a thickness direction due to the difference between inner and outer pressures. Disclosure of Invention

Technical Problem

[7] The present invention is designed to solve the problems of the prior art, and therefore it is an object of the present invention to provide a flat plate heat pipe that may have a flat plate case in a non-joining manner, be provided with a wick structure of high efficiency, and be capable of keeping a case shape. The present invention is also directed to providing a method for manufacturing the flat plate heat pipe. Technical Solution

[8] In order to accomplish the above object, the present invention provides a flat plate heat pipe, which includes a flat plate case having a plurality of grooves formed in an inner side thereof and having a successive circumferential surface such that both ends thereof are finally sealed with a coolant being injected into an inner space thereof; and a screen mesh put into the inner space of the flat plate case.

[9] Preferably, the grooves are extended in a length direction of the flat plate case and formed at regular intervals along an inner circumferential direction of the flat plate case.

[10] In another aspect of the present invention, there is also provided a method for manufacturing a flat plate heat pipe, which includes preparing a pipe with a circular section; forming a plurality of grooves in an inner side of the pipe; compressing the pipe into a shape of a flat plate case; putting a screen mesh into the flat plate case; and injecting a coolant into the flat plate case and then sealing the flat plate case.

[11] In still another aspect of the present invention, there is also provided a method for manufacturing a flat plate heat pipe, which includes extruding a flat plate case to have a plurality of grooves formed in an inner side thereof; putting a screen mesh into the flat plate case; and injecting a coolant into the flat plate case and then sealing the flat plate case..

[12] Preferably, the grooves are extended in a length direction of the flat plate case and formed at regular intervals along an inner circumferential direction of the flat plate case.

[13] The inside of the flat plate case may kept in vacuum before the coolant is injected therein.

[14] As an alternative, a flushing process for removing non-condensed gas except the coolant may be conducted after the coolant is injected into the flat plate case. Brief Description of the Drawings [15] Other objects and aspects of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawing in which:

[16] FIG. 1 is a perspective view showing a flat plate heat pipe according to a preferred embodiment of the present invention;

[17] FIG. 2 is a flowchart illustrating a method for manufacturing the flat plate heat pipe according to one embodiment of the present invention; and

[18] FIG. 3 is a flowchart illustrating a method for manufacturing the flat plate heat pipe according to another embodiment of the present invention.

[19] < Reference Numerals of Essential Parts in the Drawings >

[20] 100: flat plate case 101 : groove

[21] 102: screen mesh

Best Mode for Carrying Out the Invention

[22] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the invention, so it should be understood that other equivalents and modifications could be made thereto without departing from the spirit and scope of the invention.

[23] FIG. 1 is a perspective view showing a flat plate heat pipe according to a preferred embodiment of the present invention.

[24] Referring to FIG. 1, the flat plate heat pipe according to the preferred embodiment of the present invention includes a flat plate case 100 finally sealed with a coolant filled therein, and a screen mesh 102 put into the flat plate case 100.

[25] The flat plate case 100 has a plurality of grooves 101 formed in an inner side thereof, and a circumferential surface of the flat plate case 100 is formed in a successive structure without any joining. Such a flat plate case 100 may be provided in a way of compressing a pipe with a circular section into a plate shape or extruding a flat plate pipe shape using a mold.

[26] The grooves 101 are preferably extended in a length direction of the flat plate case

100, and a plurality of grooves are preferably formed at regular intervals along an inner circumferential direction of the flat plate case 100. Such grooves 101 give a wick structure that may contain a coolant in the flat plate heat pipe. [27] The screen mesh 102 is put into an inner space of the flat plate case 100 to prevent the flat plate case 100 from being deformed in a thickness direction and also give channels for a coolant in a vapor or liquid state.

[28] That is to say, the flat plate case 100 is finally sealed at both ends thereof while a coolant is filled in the inner space, so a pressure is applied in a thickness direction due to the difference between inner and outer pressures. At this time, if the screen mesh 102 is provided in the flat plate case 100, the screen mesh 102 supports the flat plate case 100, thereby preventing the flat plate case 100 from being deformed in a thickness direction. The screen mesh 102 in which wires are woven up and down in turns ensures a coolant channel to give a heat transfer and diffusion function. This principle is well disclosed in the Korean Patent Registration No. 495,699, so it is not described in detail here.

[29] The flat plate heat pipe configured as mentioned above is mounted such that a part of its outer side is contacted with a heat source that should be cooled. The heat generated from the heat source is transferred to the inner side of the flat plate case 100, and in this area, a coolant contained in the grooves 101 is evaporated and then diffused in all directions through the inner space of the flat plate case 100 and the screen mesh 102. The coolant then emits heat in the grooves 101 in a cooling area where the heat sink is mounted, and is then condensed. The heat emitted in the condensation process is transferred to the heat sink, and then emitted out in a forced convection manner using a cooling fan. In addition, the condensed coolant returns to the heat sink again by means of a capillary force by the grooves 101 and the screen mesh 102, and then the above process is repeated.

[30] FIG. 2 is a flowchart illustrating a method for manufacturing a flat plate heat pipe according to one embodiment of the present invention.

[31] Referring to FIG. 2, the method for manufacturing a flat plate heat pipe according to one embodiment of the present invention includes the steps of preparing a pipe with a circular section (Step SlOO), forming a plurality of grooves 101 in an inner side of the pipe (Step SlOl), compressing the pipe into a shape of a flat plate case 100 (Step S 102), putting a screen mesh 102 into the flat plate case 100 (Step S 103), and injecting a coolant into the flat plate case and finally sealing the flat plate case (Step S 104).

[32] In the step of forming the grooves 101 (Step SlOl), the inner side of the flat plate case 100 is grooved in a length direction of the flat plate case 100, and it is preferred that the grooves are formed at regular intervals along an inner circumferential direction of the flat plate case 100.

[33] The Step S 104 may selectively adopt a process for keeping the inside of the flat plate case 100 in a vacuum state before the coolant is injected, or a flushing process for removing non-condensed gas except the coolant after the coolant is injected. [34] FIG. 3 is a flowchart illustrating a method for manufacturing a flat plate heat pipe according to another embodiment of the present invention.

[35] Referring to FIG. 3, the method for manufacturing a flat plate heat pipe according to another embodiment of the present invention includes the steps of extruding a flat plate case 100 with grooves 101 formed therein (Step S200), putting a screen mesh 102 into the flat plate case 100 (Step S201), and injecting a coolant into the flat plate case and then finally sealing the flat plate case (Step S202).

[36] The Step S200 is progressed as an extruding process using a mold with a shape corresponding to the flat plate case 100 and the grooves 101. The flat plate case 100 prepared by the extruding process has no joining on its circumference, and a plurality of grooves 101 extended in a length direction are formed in its inner side.

[37] Similarly to the former embodiment, the Step S202 may adopt a process for keeping the inside of the flat plate case 100 in a vacuum state before the coolant is injected, or a flushing process for removing non-condensed gas except the coolant after the coolant is injected.

[38] The present invention has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. Industrial Applicability

[39] According to the present invention, a flat plate case may be processed in a non- joining manner, so it is possible to facilitate its manufacture and lower a product cost.

[40] In addition, a wick structure for promoting evaporation and condensation of a coolant may be provided by means of the grooves in the inner side of the flat plate case, and also it is possible to prevent compression of the flat plate heat pipe owing to the screen mesh and also ensure vapor and liquid channels of the coolant.

Claims

[1] A flat plate heat pipe, comprising: a flat plate case having a plurality of grooves formed in an inner side thereof and having a successive circumferential surface such that both ends thereof are finally sealed with a coolant being injected into an inner space thereof; and a screen mesh put into the inner space of the flat plate case. [2] The flat plate heat pipe according to claim 1, wherein the grooves are extended in a length direction of the flat plate case and formed at regular intervals along an inner circumferential direction of the flat plate case. [3] A method for manufacturing a flat plate heat pipe, comprising: preparing a pipe with a circular section; forming a plurality of grooves in an inner side of the pipe; compressing the pipe into a shape of a flat plate case; putting a screen mesh into the flat plate case; and injecting a coolant into the flat plate case and then sealing the flat plate case. [4] A method for manufacturing a flat plate heat pipe, comprising: extruding a flat plate case to have a plurality of grooves formed in an inner side thereof; putting a screen mesh into the flat plate case; and injecting a coolant into the flat plate case and then sealing the flat plate case. [5] The method for manufacturing a flat plate heat pipe according to claim 3 or 4, wherein the grooves are extended in a length direction of the flat plate case and formed at regular intervals along an inner circumferential direction of the flat plate case. [6] The method for manufacturing a flat plate heat pipe according to claim 3 or 4, wherein the inside of the flat plate case is kept in vacuum before the coolant is injected therein. [7] The method for manufacturing a flat plate heat pipe according to claim 3 or 4, wherein a flushing process for removing non-condensed gas except the coolant is conducted after the coolant is injected into the flat plate case.