Heat transfer device and method of making same

• US 7,028,759 B2
• Filed: 01/27/2004
• Issued: 04/18/2006
• Est. Priority Date: 06/26/2003
• Status: Expired due to Fees

• Current Assignee: Thermal Corporation (Roper Technologies, Inc.)
• Original Assignee: Thermal Corporation (Roper Technologies, Inc.)
• Inventors: Rosenfeld, John H., Ernst, Donald M.
• Primary Examiner(s): DUONG, THO V
• Application Number:
  US10/765,660
• Publication Number:
  US 20050022984A1
• Time in Patent Office: 812 Days
• Field of Search: 165/104.26, 165/104.21, 165/185, 165/80.3, 165/133, 165/907, 419/2, 419/6, 361/700, 298/900.32, 174/15.2, 257/715
• US Class Current: 165/104.26
• CPC Class Codes: B22F 2201/013 Hydrogen
• CPC Class Codes: B22F 2201/20 Use of vacuum
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/1103 with particular physical characteristics
• CPC Class Codes: F28D 15/0233 the conduits having a particular shape, e.g. non-circular cross-section, annular F28D15/0241, F28D15/0266 take precedence
• CPC Class Codes: F28D 15/046 characterised by the material or the construction of the capillary structure
• CPC Class Codes: F28F 2275/04 by brazing
• CPC Class Codes: H01L 23/427 Cooling by change of state, e.g. use of heat pipes by liquefied gas H01L23/445
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: Y10T 29/49353 Heat pipe device making

Abstract

A capillary structure for a heat transfer device, such as a heat pipe is provided having a plurality of particles joined together by a brazing compound such that fillets of the brazing compound are formed between adjacent ones of the plurality of particles and one or more vapor vents are defined in the capillary structer. In this way, a network of capillary passageways are formed between the particles and vapor-vents through the capillary structure so as to aid in the transfer of working fluid by capillary action, while the plurality of fillets provide enhanced thermal transfer properties between the plurality of particles so as to greatly improve over all heat transfer efficiency of the device. A method of making the capillary structure according to the invention is also presented.

Claims

1. A capillary structure for a heat transfer device comprising:

a plurality of particles joined together by a brazing compound comprising about sixty-five percent weight copper and thirty-five percent weight gold such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles wherein at least one vapor vent is defined through said capillary structure.

2. A capillary structure according to claim 1 wherein said plurality of particles comprise a first melting temperature and said brazing compound comprises a second melting temperature that is lower than said first melting temperature.

3. A capillary structure according to claim 1 wherein said plurality of particles are selected from the group consisting of carbon, tungsten, copper, aluminum, magnesium, nickel, gold, silver, aluminum oxide, and beryllium oxide.

4. A capillary structure according to claim 1 wherein said plurality of particles comprise a shape selected from the group consisting of spherical, oblate spheroid, prolate spheroid, ellipsoid, polygonal, and filament.

5. A capillary structure according to claim 1 wherein said plurality of particles comprise at least one of copper spheres and oblate copper spheroids having a melting point of about one thousand eighty-three °

C.

6. A capillary structure according to claim 1 wherein said brazing compound comprises six percent by weight of a finely divided copper/gold.

7. A capillary structure according to claim 1 wherein said brazing compound is present in the range from about two percent to about ten percent by weight.

8. A capillary structure according to claim 1 wherein said plurality of particles comprise copper powder comprising particles sized in a range from about twenty mesh to about two-hundred mesh.

9. A capillary structure for a heat transfer device comprising:

a plurality of particles joined together by a brazing compound comprising about sixty-five percent weight copper and thirty-five percent weight gold such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles wherein a plurality of vapor vents are defined through said capillary structure.

10. A capillary structure according to claim 9 wherein said vapor vents comprise a cross-sectional profile selected from the group consisting of cylindrical, conical, frustoconical, triangular, pyramidal, rectangular, rhomboidal, pentagonal, hexagonal, octagonal, polygonal and curved.

11. A heat pipe comprising:

a hermetically sealed and partially evacuated enclosure, said enclosure comprising internal surfaces;

a wick disposed on at least one of said internal surfaces and comprising a plurality of particles joined together by a brazing compound comprising about sixty-five percent weight copper and thirty-five percent weight gold such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles wherein at least one vapor vent is defined through said capillary structure; and

a two-phase fluid at least partially disposed within a portion of said wick.

12. A heat pipe according to claim 11 wherein said plurality of particles comprise a first melting temperature and said brazing compound comprises a second melting temperature that is lower than said first melting temperature.

13. A heat pipe according to claim 11 wherein said plurality of particles are selected from the group consisting of carbon, tungsten, copper, aluminum, magnesium, nickel, gold, silver, aluminum oxide, and beryllium oxide.

14. A heat pipe according to claim 11 wherein said plurality of particles comprise a shape selected from the group consisting of spherical, oblate spheroid, prolate spheroid, polygonal, and filament.

15. A heat pipe according to claim 11 wherein said plurality of particles comprise at least one of copper spheres and oblate copper spheroids having a melting point of about 1083°

C.

16. A heat pipe according to claim 11 wherein said brazing compound is present in the range from about two percent to about ten percent by weight.

17. A heat pipe according to claim 11 wherein said plurality of particles comprise copper powder comprising particles size in a range from about twenty mesh to about two-hundred mesh.

18. A heat pipe comprising:

a hermetically sealed and partially evacuated enclosure, said enclosure comprising internal surfaces;

a wick disposed on at least one of said internal surfaces and comprising a plurality of particles joined together by a brazing compound comprising six percent by weight of a finely divided copper/gold brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles wherein at least one vapor vent is defined through said capillary structure; and

a two-phase fluid at least partially disposed within a portion of said wick.

19. A heat pipe comprising a sealed and partially evacuated tubular enclosure having an internal surface covered by a brazed wick comprising a plurality of copper particles joined together by a brazing compound comprising about sixty-five percent weight copper and thirty-five percent weight gold such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles and including a plurality of vapor vents defined through said wick;

and

a working fluid disposed within said tubular enclosure.

20. A heat pipe comprising:

a hermetically sealed and partially evacuated enclosure, said enclosure comprising internal surfaces;

a wick disposed on at least one of said internal surfaces and comprising a plurality of aluminum and magnesium particles joined together by an aluminum/magnesium intermetallic alloy brazing compound such that fillets of said brazing compound are formed between adjacent ones of said plurality of particles so as to form a network of capillary passageways between said particles wherein at least one vapor vent is defined through said capillary structure; and

a two-phase fluid at least partially disposed within a portion of said wick.