Heat pipe having a composite wick structure and method for making the same

Abstract

A heat pipe having a composite wick structure includes a first pipe, a second pipe, a third wick structure, a working fluid, an evaporating section, a condensing section and a transferring section. The inner wall of the first pipe is provided with a first wick structure. The evaporating section is formed on one side of the first pipe. The condensing section is formed on the other side of the first pipe. The transferring section is formed in the first pipe between the evaporating section and the condensing section. The second pipe is received in the first pipe and located in the transferring section. The outer wall of the second pipe is provided with a second wick structure. The third wick structure is provided between the first wick structure and the second wick structure. The working fluid is filled in the first pipe. By this structure, the condensed working fluid in the first pipe can quickly flow from the condensing section through the transferring section back to the evaporating section. The present invention also provides a method for making such a heat pipe.

1 . A heat pipe having a composite wick structure, including:
 a first pipe provided with a first wick structure on its inner wall;   an evaporating section formed on one side of the first pipe;   a condensing section formed on the other side of the first pipe away from the evaporating section;   a transferring section formed in the first pipe between the evaporating section and the condensing section;   a second pipe received in the first pipe and located in the transferring section, an outer wall of the second pipe being provided with a second wick structure;   a third wick structure provided between the first wick structure and the second wick structure; and   a working fluid filled in the first pipe.   
     
     
         2 . The heat pipe having a composite wick structure according to  claim 1 , wherein the first wick structure is constituted of a plurality of grooves formed on the inner wall of the first pipe. 
     
     
         3 . The heat pipe having a composite wick structure according to  claim 2 , wherein the second wick structure is constituted of a plurality of grooves formed on the outer wall of the second pipe. 
     
     
         4 . The heat pipe having a composite wick structure according to  claim 3 , wherein the grooves of the first pipe are aligned with the grooves of the second pipe respectively. 
     
     
         5 . The heat pipe having a composite wick structure according to  claim 3 , wherein the grooves of the first pipe are staggered with respect to the grooves of the second pipe respectively. 
     
     
         6 . The heat pipe having a composite wick structure according to  claim 1 , wherein the second wick structure is made of sintered metal powder. 
     
     
         7 . The heat pipe having a composite wick structure according to  claim 1 , wherein the second wick structure is made of metallic woven meshes. 
     
     
         8 . The heat pipe having a composite wick structure according to  claim 1 , wherein the third wick structure is made of sintered metal powder. 
     
     
         9 . The heat pipe having a composite wick structure according to  claim 1 , wherein the third wick structure is made of metallic woven meshes. 
     
     
         10 . The heat pipe having a composite wick structure according to  claim 1 , wherein the third wick structure is made of a bundle of fibers. 
     
     
         11 . The heat pipe having a composite wick structure according to  claim 1 , wherein an inner wall surface of the second pipe is a smooth surface. 
     
     
         12 . The heat pipe having a composite wick structure according to  claim 1 , wherein a solid body is formed in the evaporating section, the solid body is constituted of the first wick structure and the third wick structure. 
     
     
         13 . The heat pipe having a composite wick structure according to  claim 1 , wherein a hollow body is formed in the condensing section, the hollow body is constituted of the first wick structure and the third wick structure. 
     
     
         14 . The heat pipe having a composite wick structure according to  claim 1 , wherein the interior of the condensing section has the first wick structure. 
     
     
         15 . A method for making a heat pipe having a composite wick structure, including steps of:
 a) providing a first pipe having a first wick structure, narrowing and sealing one end of the first pipe;   b) providing a second pipe having a second wick structure, inserting the second pipe into the first pipe to form a filling space between the first wick structure and the second wick structure;   c) providing a third wick structure, filling the third wick structure into the filling space;   d) providing a heating apparatus for heating the first wick structure, the second wick structure and the third wick structure to form a composite wick structure;   e) providing a working fluid, filling the working fluid into the first pipe; and   f) providing a degassing and soldering apparatus for degassing and sealing the first pipe.   
     
     
         16 . The method according to  claim 15 , wherein the first wick structure is formed of a plurality of grooves on an inner wall of the first pipe. 
     
     
         17 . The method according to  claim 16 , wherein the second wick structure is constituted of a plurality of grooves on an outer wall of the second pipe. 
     
     
         18 . The method according to  claim 17 , wherein the grooves of the first pipe are aligned with the grooves of the second pipe respectively. 
     
     
         19 . The method according to  claim 17 , wherein the grooves of the first pipe are staggered with respect to the grooves of the second pipe respectively.