BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the present apparatus and method can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 is a longitudinal cross-sectional view of a heat pipe in accordance with a first embodiment of the present invention;
FIG. 2 is a radial cross-sectional view of the heat pipe of FIG. 1, taken along line II-II thereof;
FIG. 3 is a radial cross-sectional view of a mandrel used for manufacturing the heat pipe of FIG. 1;
FIG. 4 is a longitudinal cross-sectional view of the mandrel of FIG. 3, taken along line IV-IV thereof;
FIG. 5 is a radial cross-sectional view of the mandrel of FIG. 3 and a piece of capillary wick;
FIG. 6 is a longitudinal cross-sectional view of the mandrel and the piece of capillary wick of FIG. 5, taken along line VI-VI thereof;
FIG. 7 is a longitudinal cross-sectional view of the heat pipe before the mandrel is drawn out therefrom;
FIG. 8 is similar to FIG. 7, but with the mandrel having been drawn out from the heat pipe;
FIGS. 9-11 are radial cross-sectional views of mandrels different from the mandrel of FIG. 3;
FIG. 12 is a longitudinal cross-sectional view of a heat pipe in accordance with a second embodiment of the present invention;
FIG. 13 is a radial cross-sectional view of the heat pipe of FIG. 12, taken along line XIII-XIII thereof;
FIG. 14 is a longitudinal cross-sectional view of a heat pipe in accordance with a third embodiment of the present invention;
FIG. 15 is a radial cross-sectional view of the heat pipe of FIG. 14, taken along line XV-XV thereof; and
FIG. 16 is s longitudinal cross-sectional view of a heat pipe in accordance with related art.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 and 2 illustrate a heat pipe 10 in accordance with a first embodiment of the present invention. The heat pipe 10 comprises a straight tubular shell 120 having working media contained therein, a first capillary wick 140 positioned on an inner surface of the shell 120 and a rod-shaped second capillary wick 160 positioned on an inner side of the first capillary wick 140. A vapor channel 180 is enclosed by the first and second capillary wicks 140, 160 for transporting vapor in the shell 120. The first capillary wick 140 is circumferentially and longitudinally spread on the inner side of the shell 120. A longitudinal arched groove 142 is defined in the first capillary wick 140 for receiving the second capillary wick 160 therein. The second capillary wick 160 is attached to the first capillary wick 140 and extended into the vapor channel 180 from the longitudinal groove 142. In this embodiment the first capillary wick 140 is made via sintering metallic or ceramic powders and the second capillary wick 160 is made of fiber. Alternatively, the second capillary wick 160 can be formed using other types of wicks, such as mesh-type of wick, beehive-type wick, micro-tubes, and metallic foil.
FIGS. 3-8 illustrate a process of manufacturing the heat pipe 10. First, a cylindrical mandrel 110 is provided. The mandrel 110 longitudinally defines an arched slot 112 therein. Second, the second capillary wick 160 is partially accommodated in the slot 112 in this embodiment, as shown in FIGS. 5-6, for facilitating mass-production. Also referring to FIG. 7, the mandrel 110 and the second capillary wick 160 are inserted into the shell 120. A space between the mandrel 110 and the shell 120 is filled with metallic or ceramic powder 140a. Then, the shell 120 having the mandrel 110, the metallic or ceramic powder 140a and the second capillary wick 160 therein is sintered, so that the powder 140a becomes the first capillary wick 140 and that the second capillary wick 160 is joined with the first capillary wick 140. Simultaneously, the first capillary wick 140 is positioned on the inner side of the shell 120 due to the sintering process. After that, the mandrel 110 is drawn out from the shell 120 and the first and second capillary wicks 140, 160 are held in position in the shell 120 firmly as shown in FIG. 8. Subsequent processes such as injecting working media into the shell 120, vacuuming and sealing the shell 120 can be performed using conventional ways. Thus, a straight heat pipe 10 as shown in FIGS. 1-2 is attained. The heat pipe 10 finally can be bent to have L-shaped or U-shaped configurations. The heat pipe 10 can also be flattened to have a rectangular cross-section, such as those shown in FIGS. 13, 15 for example.
The locations of the first and second capillary wicks 140, 160 are fixed in the shell 120 of the heat pipe 10. Thus, movement of the first and second capillary wicks 140, 160 in the vapor channel 180 is prevented, even if the heat pipe is bent or flattened.
In practice, other mandrels having different configurations can be substituted for the mandrel 110 of FIG. 3. FIGS. 9-11 show examples of mandrels suitable to substitute for the mandrel 110 of FIG. 3. Correspondingly, the configuration of the second capillary wick 160 can be changed accordingly (see FIGS. 13, 15).
FIGS. 12-13 show a heat pipe 20 in accordance with a second embodiment of the present invention. The heat pipe 20 is U-shaped and flattened to have a rectangular cross-section. The heat pipe 20 comprises a shell 220, a first capillary wick 240 and a second capillary wick 260. The first capillary wick 240 is arranged on an inner surface of the shell 220. The second capillary wick 260 is united together with the first capillary wick 240 and located adjacent to an outer wall 224 of the shell 220.
FIGS. 14-15 show a heat pipe 30 in accordance with a third embodiment of the present invention. The heat pipe 30 is similar to the heat pipe 20, but the second capillary wick 360 is located adjacent to an inner wall 324 of the shell 320.
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Patent Application
20070267179
