Flat heat pipe and method for manufacturing the same

Abstract

An exemplary flat heat pipe with an evaporator section and a condenser section at opposite ends thereof includes a hollow flat casing, a first wick structure and a solid and sintered second wick structure. The first wick structure includes a top plate and a bottom plate opposite to the top plate. The first wick structure is received in the casing, and extends from the evaporator section to the condenser section. The second wick structure is disposed in the casing at the evaporator section. The second wick structure contacts the top and bottom plates and joins the first wick structure. A method for manufacturing the heat pipe is also provided.

1 . A flat heat pipe with an evaporator section and a condenser section at opposite ends thereof, the flat heat pipe comprising:
 a hollow flat casing comprising a top plate and a bottom plate opposite to the top plate;   a first wick structure received in the casing and extending from the evaporator section to the condenser section; and   a solid, sintered second wick structure disposed in the casing at the evaporator section, the second wick structure contacting the top and bottom plates and joining the first wick structure.   
     
     
         2 . The flat heat pipe of  claim 1 , wherein the second wick structure is disposed along a center axis of the evaporator section. 
     
     
         3 . The flat heat pipe of  claim 1 , wherein the first wick structure is a hollow tube made of woven wires. 
     
     
         4 . The flat heat pipe of  claim 1 , wherein the first and second wick structures cooperatively form a composite wick structure via sintering. 
     
     
         5 . The flat heat pipe of  claim 4 , wherein a vapor channel is defined between the composite wick structure and a lateral inner surface of the casing. 
     
     
         6 . The flat heat pipe of  claim 1 , further comprising another first wick structure, the second wick structure disposed between the two first wick structures. 
     
     
         7 . The flat heat pipe of  claim 6 , wherein the casing further comprises two side plates interconnecting the top and bottom plates, one of the two first wick structures and one of the two side plates cooperatively define a first vapor channel therebetween, and the other first wick structure and the other side plate cooperatively define a second vapor channel therebetween. 
     
     
         8 . The flat heat pipe of  claim 1 , wherein the first wick structure is enclosed in the second wick structure at the evaporator section. 
     
     
         9 . The flat heat pipe of  claim 8 , wherein the casing further comprises two side plates interconnecting the top and bottom plates, one of two lateral sides of the second wick structure and one of the two side plates cooperatively define a first vapor channel therebetween, and the other lateral side of the second wick structure and the other side plate cooperatively define a second vapor channel therebetween. 
     
     
         10 . The flat heat pipe of  claim 1 , further comprising another two first wick structures, wherein two of the three first wick structures are disposed at opposite sides of the second wick structure, respectively, and the other first wick structure is enclosed in the second wick structure at the evaporator section. 
     
     
         11 . The flat heat pipe of  claim 10 , wherein the casing further comprises two side plates interconnecting the top and bottom plates, one of the two first wick structures disposed at opposite sides of the second wick structure and one of the two side plates cooperatively define a first vapor channel therebetween, and the other of the two first wick structures disposed at opposite sides of the second wick structure and the other side plate cooperatively define a second vapor channel therebetween. 
     
     
         12 . A flat heat pipe with an evaporator section and a condenser section at opposite ends thereof, the flat heat pipe comprising:
 a hollow flat casing cooperatively formed by a top plate, a bottom plate opposite to the top plate, and two side plates interconnecting the top and bottom plates; and   a composite wick structure disposed in the casing, the composite wick structure comprising a first wick structure in the form of woven wires, and a solid, sintered second wick structure joining the first wick structure, the first wick structure extending from the evaporator section to the condenser section, the second wick structure disposed only in the evaporator section, and the first and second wick structures contacting the top and bottom plates of the casing.   
     
     
         13 . The flat heat pipe of  claim 12 , wherein the second wick structure is disposed along a center axis of the evaporator section. 
     
     
         14 . The flat heat pipe of  claim 12 , wherein a first vapor channel and a second vapor channel are respectively defined between two lateral sides of the structure and the two side plates of the casing. 
     
     
         15 . The flat heat pipe of  claim 14 , wherein the first wick structure is enclosed in the second wick structure in the evaporator section, and the first and second vapor channels are respectively defined between two lateral sides of the second wick structure and the two side plates of the casing. 
     
     
         16 . The flat heat pipe of  claim 14 , wherein the composite wick structure further comprises another one first wick structure, the second wick structure is disposed between the two first wick structures, and the first and second vapor channels are respectively defined between the two first wick structures and the two side plates of the casing. 
     
     
         17 . The flat heat pipe of  claim 16 , wherein the composite wick structure further comprises another one first wick structure enclosed in the second wick structure in the evaporator section. 
     
     
         18 . A method for manufacturing a heat pipe, the method comprising:
 providing a cylindrical mandrel, a hollow cylindrical tube and a first wick structure, the mandrel defining a longitudinal slot in a circumferential surface thereof, one end of the mandrel defining a cutout in the circumferential surface, the cutout communicating with the slot, and an inner diameter of the tube being substantially equal to an outer diameter of the mandrel;   inserting the mandrel and the first wick structure into the tube, the first wick structure received in the slot of the mandrel;   filling an amount of metal powder into the cutout of the mandrel in the tube, and sintering the metal powder to form a solid second wick structure, wherein the second wick structure is joined to the first wick structure and part of an inner surface of the tube;   drawing the mandrel out of the tube;   injecting a working medium into the tube, and evacuating and sealing the tube; and   flattening the tube until the second wick structure contacts another part of the inner surface of the tube, the two parts of the inner surface of the tube being at opposite sides of the flattened tube.   
     
     
         19 . The method for manufacturing a heat pipe of  claim 18 , wherein the cutout is axially shorter than the slot. 
     
     
         20 . The method for manufacturing a heat pipe of  claim 19 , wherein the cutout defines a generally rainbow-shaped cross section.