Structure of a heat pipe

• US 4,921,041 A
• Filed: 06/15/1988
• Issued: 05/01/1990
• Est. Priority Date: 06/23/1987
• Status: Expired due to Term

• Current Assignee: Actronics Kabushiki Kaisha
• Original Assignee: Actronics Kabushiki Kaisha
• Inventors: Akachi, Hisateru
• Primary Examiner(s): DAVIS JR, ALBERT
• Application Number:
  US07/207,318
• Time in Patent Office: 685 Days
• Field of Search: 165/104.29, 165/104.22, 165/104.24, 165/104.26
• US Class Current: 165/104.29
• CPC Class Codes: F28D 15/00 Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies F28D17/00, F28D19/00, F28D20/00 take precedence
• CPC Class Codes: F28D 15/0266 with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers F28D15/043 takes precedence
• CPC Class Codes: F28D 15/0275 Arrangements for coupling heat-pipes together or with other structures, e.g. with base blocks; Heat pipe cores
• CPC Class Codes: F28D 15/06 Control arrangements therefor
• CPC Class Codes: F28F 13/18 by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
• CPC Class Codes: F28F 2013/001 Particular heat conductive materials, e.g. superconductive elements for thermal joints F28F2013/006

Abstract

A structure of a loop-type heat pipe is disclosed in which a heat carrying fluid, preferably a bi-phase non-condensative fluid, circulates in a loop form in itself under its own vapor pressure at a high speed within an elongate pipe so as to repeat vaporization and condensation, thus carrying out a heat transfer. A structure of the loop-type heat pipe includes the elongate pipe, both ends thereof being air-tightly interconnected to form a loop-type container, the heat carrying fluid, at least one heat receiving portion and at least one heat radiating portion, both being placed at given portions of a elongate pipe, and at least one check valve for limiting a stream direction of the heat carrying fluid. A check valve(s) propels and amplifies forces generated by the heat carrying fluid and its vapor to move toward the stream direction limited by the check valve(s) so that the heat carrying fluid circulates in the stream direction through the closed-loop passage defined by the elongate pipe at the high speed, repeating vaporization at the heat receiving and radiating portions.

Claims

1. A structure of a loop-type heat pipe, comprising:

(a) a continuous elongate tube of continuous capillary dimension having both ends thereof air-tightly connected to each other to form a continuous capillary loop-type flow passage;

(b) a heat carrying fluid within the elongate tube in an amount sufficient to allow flow of the fluid through the loop flow passage in a closed state defined by the elongate tube;

(c) at least one heat receiving portion located on a first part of the elongate tube for heating the fluid therein;

(d) at least one heat radiating portion located on a second part of the elongate tube for cooling the fluid therein; and

(e) flow control means located within the loop-type flow passage for limiting flow of the heat carrying fluid to a single direction in the flow passage, the flow control means together with mutual actions of vapor pressure generated due to the vaporization at the heat receiving portion and attracting force generated due to condensation of vapor at the heat radiating portion providing propelling force and amplifying the propelling force for the heat carrying fluid so as to circulate the heat carrying fluid in the single direction in the flow passage from the heat receiving portion to the heat radiating portion.

2. A structure of the loop-type heat pipe as set forth in claim 1, wherein the heat carrying fluid includes a bi-phase changeable condensative fluid and the amount of the heat carrying fluid filled in the flow passage is below substantially 95 percent with respect to a volume of the flow passage.

3. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe has an inner diameter capable of circulating the heat carrying fluid through the flow passage irrespective of the amount of the heat carrying fluid.

4. A structure of the loop-type heat pipe as set forth in claim 1, wherein at least either of the heat receiving or radiating portions has a sufficiently extended heat transmission area.

5. A structure of the loop-type heat pipe as set forth in claim 1, wherein the heat carrying fluid comprises a predetermined amount of a predetermined working liquid mixed with a predetermined amount of non-condensative gas.

6. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe is made of a soft metal and wherein the heat carrying fluid is a working liquid such that a total product value of numerical values of a saturated vapor pressure thereof indicated in a predetermined temperature region and of an inverse number of a liquid-phase dynamic viscosity coefficient at each same temperature is greater than that of Freon-11 at each same temperature.

7. An structure of the loop-type heat pipe as set forth in claim 6, wherein the elongate pipe is made of pure copper.

8. A structure of the heat pipe as set forth in claim 6, wherein the elongate pipe is made of aluminum.

9. A structure of the loop-type heat pipe as set forth in claim 1, wherein all or predetermined part of the elongate pipe is completely annealed or softened so that the elongate pipe is universally flexed.

10. A structure of the loop-type heat pipe as set forth in claim 1, wherein the heat receiving portion and heat radiating portion are provided in an elongate pipe in a couple for each part of the elongate pipe and wherein the first means comprises two check valves located so as to sandwich the couple of the heat receiving and radiating portions.

11. A structure of the loop-type heat pipe as set forth in claim 10, wherein a predetermined portion between a heat receiving portion and heat radiating portion is formed of another pipe made of an electrically insulating material capable of resisting the internal and external pressures and resisting a predetermined number of temperature cycles and the working liquid comprises an electrically insulative working liquid.

12. A structure of the loop-type heat pipe as set forth in claim 10, wherein a plurality of elongated pipes corresponding to forward and rearward stream passages of the working liquid are provided to form the loop-type container, the plurality of elongate pipes being mutually twisted at a predetermined part thereof.

13. A structure of the loop-type heat pipe as set forth in claim 12, wherein the predetermined part is a heat receiving portion and is held within a metallic tube, all clearance within the metallic tube being filled with a filling material.

14. A structure of the loop-type heat pipe as set forth in claim 12, wherein the predetermined part is the heat radiating portion.

15. A structure of the loop-type heat pipe as set forth in claim 10, wherein the elongate pipe has a plurality of bent portions having a predetermined radius of curvatures to form a zig-zag shaped loop-type container, the bent portions forming stream direction switching portions of the working liquid.

16. A structure of the loop-type heat pipe as set forth in claim 15, wherein each turned portion of the elongate pipe is formed of a heat insulating portion, the heat insulating portions being bundled, inserted, and held into a predetermined tubular structure, all clearances within the tubular structure being air-tightly filled with a predetermined filling material.

17. A structure of the loop-type heat pipe as set forth in claim 15, wherein the elongate pipe constitute a heat exchanger.

18. A structure of the loop-type heat pipe as set forth in claim 1, wherein the first means comprises at least one check valve disposed in the flow passage of the elongate pipe except the heat receiving and radiating portions.

19. A structure of the loop-type heat pipe as set forth in claim 18, wherein the check valve includes a valve seat formed of a thin capillary in an internal wall of the flow passage, a valve body formed of a ball made of corundum (Al₂ O₃), and valve body stopper for maintaining A valve body float at a position within a predetermined distance from the valve seat.

20. A structure of the loop-type heat pipe as set forth in claim 19, wherein the valve body is made of aluminum.

21. A structure of the loop-type heat pipe as set forth in claim 19, wherein the valve body is made of pure copper.

22. A structure of the loop-type heat pipe as set forth in claim 1, wherein the first part of the elongate pipe is disposed in parallel to the second part of the elongate pipe, with a portion thereof linking both first and second parts being bent through a predetermined radius of curvature to form a direction switching portion of the heat carrying fluid.

23. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe is constituted by a plurality of mutually juxtaposed thin pipes, one end of the juxtaposed pipes being linked through a linkage member.

24. A structure of the loop-type heat pipe as set forth in claim 23, wherein the linkage member comprises a header which integrally links a plurality of the elongate pipes to form a stream direction switching portion of the working liquid.

25. A structure of the loop-type heat pipe as set forth in claim 23, wherein the linkage member comprises a bent pipe having a predetermined radius of curvature which links one group of the juxtaposed pipes in which the working liquid streams toward the bent pipe with another group of the juxtaposed pipes in which the working liquid streams from the bent pipe.

26. A structure of the loop-type heat pipe as set forth in claim 25, wherein each of the juxtaposed pipes has any one of cross sections in circular, elliptical, square, rectangular shapes, and a multiple number of capillary grooves.

27. A structure of the loop-type heat pipe as set forth in claim 1, wherein an outer surface of an elongate pipe is covered with an electrically insulating coating having a heat resistant characteristic according to a use temperature of the elongate pipe and a good heat conductivity.

28. A structure of the loop-type heat pipe as set forth in claim 27, wherein the electrically insulating coating is an enamel paint baked coating.

29. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe constitutes a winding used in an electric motor, generator, transformer, and electromagnet.

30. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe constitutes a conductor of an electric wire used to cool an insulating coating for preventing fire of the wire.

31. A structure of the loop-type heat pipe as set forth in claim 30, wherein the elongate pipe comprises a plurality of loop-type containers incorporated into a sealed metallic tube, the sealed metallic tube having a cavity chamber constituting the stream direction switching portion of the working liquid at each one end of the loop-type containers.

32. A structure of the loop-type heat pipe as set forth in claim 31, wherein the cavity chamber is provided with a rotary turbine which rotates in response to the stream of the working fluid and means for outputting a rotation energy of the rotary turbine externally.

33. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe constituting the loop-type container is formed as a hollow electric wire.

34. A structure of the loop-type heat pipe as set forth in claim 33, wherein the hollow electric wire is coated with an electrically insulating fiber.

35. A structure of the loop-type heat pipe as set forth in claim 34, wherein the hollow electric wire is coated with an enamel painting in which any one of tung oil, polyurethane, polyester, polyamide, or polyimide is a main constituent.

36. A structure of the loop-type heat pipe as set forth in claim 1, wherein the first means includes a heat radiating portion and heat receiving portion, the heat radiating portion being wound on a conduit of an electric power cable in an underground, the heat radiating portion being extended in a soil.

37. A structure of the loop-type heat pipe as set forth in claim 1, which further comprises a plurality of optical fibers extended around the elongate pipe, a flame resistant layer extended around the optical fibers, and a heat resistant layer extended around the flame resistant layer.

38. A structure of the loop-type heat pipe as set forth in claim 37, wherein the optical fibers are extended around the elongate pipe via grooves.

39. A structure of the loop-type heat pipe as set forth in claim 1, which further comprises a super conductive object coating layer extended around an outer periphery of the elongate pipe and a metallic tubular coating extended around the super conductive object coating layer.

40. A structure of the loop-type heat pipe as set forth in claim 39, wherein the metallic tubular coating is made of pure copper.

41. A structure of the loop-type heat pipe as set forth in claim 39, wherein the super conductive object coating layer, the metallic tubular coating, and elongate pipe are integrated by drawing or swaging process.

42. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe has a cross section in a rectangular shape and which further comprises a plurality of super conductive objects in tape forms grasped by means of the elongate pipe container.

43. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe has a cross section in a rectangular shape and which further comprises a plurality of wires made of super conductive objects.

44. A structure of the loop-type heat pipe as set forth in claim 1, wherein the elongate pipe comprises a plurality of pipes in a group, the pipe group being placed within a metallic tube and an outer periphery thereof being coated with a super conductive material, all gaps provided between the inner wall of the metallic tube and the pipe group being filled with a super conductive material and wherein the working fluid includes a low temperature workable liquid which operates sufficiently at a temperature lower than a critical temperature of the super conductive material.