Heat pipe

Abstract

A heat pipe includes a metal tube and a sintered powder layer. An inner sidewall of the metal tube thereon defines a clearance area. The sintered powder layer is formed on the inner sidewall without covering the clearance area, such that the clearance area is exposed out without being covered by the sintered powder layer. Because of no sintered powder on the clearance area, the heat pipe can be bent at the clearance area without damaging the capillary structure formed by the sintered powder. The flow path of the working fluid is not interrupted or influenced, so the heat transfer efficiency can be maintained, which overcomes the decrement of the heat transfer efficiency of a bent heat pipe in the prior art.

What is claimed is: 
     
         1 . A heat pipe, comprising:
 a metal tube, an inner sidewall of the metal tube defining a clearance area; and   a sintered powder layer formed on the inner sidewall, the clearance area being exposed out without being covered by the sintered powder layer.   
     
     
         2 . The heat pipe of  claim 1 , wherein the metal tube is a copper tube, and the sintered powder layer is a sintered copper powder layer. 
     
     
         3 . The heat pipe of  claim 1 , wherein the metal tube extends in a direction, and the clearance area extends in the direction to an end portion of the metal tube. 
     
     
         4 . The heat pipe of  claim 3 , wherein a thickness of a portion of the sintered powder layer opposite to the clearance area is thicker than that of other portions of the sintered powder layer. 
     
     
         5 . The heat pipe of  claim 1 , wherein the metal tube has a bent portion, and the clearance area is at an inner side or an outer side of the bent portion. 
     
     
         6 . The heat pipe of  claim 5 , wherein a value of a bending radius of the bent portion is smaller than three times a value of a diameter of the metal tube.