Abstract: A pulsating heat pipe (10) includes an elongate capillary tube (11), a working fluid (15) disposed within the elongate tube and an artery mesh (13) disposed in the elongate tube. The capillary tube includes a plurality of heat receiving portions (112) located on a first predetermined part of the elongate tube, and a plurality of heat radiating portions (114) located on a second predetermined part of the elongate tube. The heat receiving and heat radiating portions are alternatively disposed on the elongate tube. The working fluid is propelled to flow between the heat receiving and heat radiating portions via a first channel (132) defined in the artery mesh and a second channel (133) defined between the artery mesh and the elongate tube.

Abstract: A heat pipe (10) includes a longitudinal casing (12) having an evaporator section (121) and a condenser section (122), a major wick structure (14) disposed in an inner wall of the casing, at least one assistant wick structure (16) contacting with an inner wall of the major wick structure and extending between the evaporator section and the condenser section, and working medium filling the casing and saturating the major and assistant wick structures. A diameter of a cross section of the assistant wick structure is smaller than a diameter of a cross section of the major wick structure. The assistant wick structure cooperates with the major wick structure to form a composite wick structure, which increases the capillary force inside the heat pipe and further increases the heat transfer capability of the heat pipe.

Abstract: A heat pipe (20) includes a metal casing (22) having an evaporating section (70) and a condensing section (80). A first type of capillary wick (241) is provided in the evaporating section and a second type of capillary wick (242) is provided in the condensing section. The average capillary pore size of the second type of capillary wick is larger than that of the first type of capillary wick. The second type of capillary wick provides a low flow resistance to the liquid condensed in the condensing section to flow back and the first type of capillary wick develops a large capillary force to draw the liquid back to the evaporating section from the condensing section. Thus, the condensed liquid is brought back from the condensing section to the evaporating section in an accelerated manner.