HEAT PIPE

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority of China Patent Application No. 202421755924.8, filed on Jul. 23, 2024, the entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a heat pipe, and, in particular, to a heat pipe with capillary structures inside.

Description of the Related Art

Heat pipes currently in use mainly consist of a closed body, a capillary structure disposed inside the body, and a heat transfer fluid filled inside the body. The heat pipe can be divided into an evaporating section and a condensing section. When in operation, the evaporating section of the heat pipe is close to the heat source, and the heat generated by the heat source causes the heat transfer fluid in the evaporating section to evaporate or vaporize. The resulting vapor flows to the condensing section, where it releases the latent heat and condenses back into liquid, which is then guided back to the evaporating section by the capillary structure. In this way, the heat pipe can achieve the purpose of heat dissipation from the heat source.

Mesh and fiber are used to form the capillary structures. However, conventional capillary structures have certain disadvantages, such as higher thermal resistance, they take up too much space inside the bodies, they are difficult to manufacture, and they are not very compatible with different heat sources.

Therefore, it is important to increase the space for heat transfer and improve heat dissipation without affecting the manufacturing process.

BRIEF SUMMARY OF THE INVENTION

According to some embodiments of the present disclosure, a heat pipe is provided, including a body, a first capillary structure, and a second capillary structure. The body has a hollow structure. The first capillary structure is disposed inside the body, extends in an axial direction of the body, and has a 3D structure. The second capillary structure surrounds the first capillary structure, is attached to a pipe wall of the body, and has a 2D structure. The first and second capillary structures are bonded together outside the body, and then they are disposed inside the hollow structure. The second capillary structure has an opening, from which the first capillary structure is exposed. The exposed portion of the first capillary structure is in contact with the pipe wall.

In some embodiments, the length of the second capillary structure extending along the pipe wall is three quarters of the circumference of a cross-section of the body in a direction that is perpendicular to the axial direction.

In some embodiments, the body includes one evaporating section and two condensing sections. The evaporating section is located between the two condensing sections. The evaporating section corresponds to one or more heat sources outside the heat pipe.

In some embodiments, the first capillary structure is located at the evaporating section and the two condensing sections, and the second capillary structure is located only at the evaporating section.

In some embodiments, the portions of the first capillary structure that is located at the two condensing sections only contact the pipe wall on one side.

In some embodiments, the two condensing sections, the first capillary structure, and the second capillary structure are all symmetrical to a centerline of the evaporating section.

In some embodiments, a length of the opening of the second capillary structure in the axial direction corresponds to a length of the one or more heat sources.

In some embodiments, a width of the opening of the second capillary structure in a direction perpendicular to the axial direction is greater than a diameter of the first capillary structure.

In some embodiments, the second capillary structure further comprises a supporting portion that is disposed at the middle portion of the opening, dividing the opening into a first opening and a second opening.

In some embodiments, the lengths of the first and second openings in the axial direction are different, respectively corresponding to lengths of a plurality of heat sources outside the heat pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It should be noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1A shows a longitudinal cross-section of the heat pipe when viewed perpendicular to the axial direction, in accordance to some embodiments of the present disclosure.

FIG. 1B shows a radial cross-section of the heat pipe when viewed in the axial direction, in accordance to some embodiments of the present disclosure.

FIG. 2A shows a schematic view of the position of the heat pipe relative to the heat source, in accordance to some embodiments of the present disclosure.

FIG. 2B shows a schematic view of the connection between the first capillary structure and the second capillary structure, in accordance to some embodiments of the present disclosure.

FIG. 2C shows a schematic view of the connection between the first capillary structure and the second capillary structure, in accordance to other embodiments of the present disclosure.

FIG. 3A shows a schematic view of the position of the heat pipe relative to the heat source, in accordance to other embodiments of the present disclosure.

FIG. 3B shows a schematic view of the connection between the first capillary structure and the second capillary structure, in accordance to some embodiments of the present disclosure.

FIG. 3C shows a schematic view of the connection between the first capillary structure and the second capillary structure, in accordance to yet other embodiments of the present disclosure.

FIG. 4 is a broken line graph showing the effect of different capillary structures on the maximum heat transfer.

FIG. 5 shows a schematic view of the connection between the first capillary structure and the second capillary structure outside the body, in accordance to other embodiments of the present disclosure.

FIG. 6 shows a schematic view of the configuration of the first capillary structure and the second capillary structure inside the body, in accordance to other embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact.

In addition, the present disclosure may repeat reference numerals and/or letters in the various embodiments. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a feature on, connected to, and/or coupled to another feature in the present disclosure that follows may include embodiments in which the features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the features, such that the features may not be in direct contact. In addition, spatially relative terms, for example, “vertical,” “above,” “over,” “below,”, “bottom,” etc. as well as derivatives thereof (e.g., “downwardly,” “upwardly,” etc.) are used for ease of the present disclosure of one features relationship to another feature. The spatially relative terms are intended to cover different orientations of the device including the features.

Referring to FIG. 1, FIG. 1 shows a schematic view of the cross-section of the heat pipe 100, in accordance to some embodiments of the present disclosure. FIG. 1A shows a longitudinal cross-section of the heat pipe 100 when viewed perpendicular to the axial direction A, and FIG. 1B shows a radial cross-section of the heat pipe 100 when viewed in the axial direction A.

As shown in FIG. 1A, the heat pipe 100 mainly includes a body 110, a first capillary structure 120, and a second capillary structure 130.

The body 110 is formed to be in a closed pipe shape. A hollow structure 111 is formed therein. The hollow structure 111 is surrounded by the pipe wall 112. The hollow structure 111 is filled by heat transfer fluid (not shown). Heat dissipation can be achieved through a cycle of vaporization and liquefaction of the heat transfer fluid within the body 110. Furthermore, as shown in FIG. 1A, the body 110 may include an evaporating section E and two condensing sections C. The evaporating section E is located between the two condensing sections C. In some embodiments, the evaporating section E may correspond to one or more heat sources outside the heat pipe 100, e.g. the heat source 200 shown in FIG. 2A or the first heat source 201 and the second heat source 202 shown in FIG. 3A.

The first capillary structure 120 is disposed inside the body 110, extends in an axial direction A of the body 110, and has a 3D structure. In some embodiments, the first capillary structure 120 may be a fiber structure, and be formed into a long strip. As shown in FIG. 1A, the first capillary structure 120 is located at the evaporating section E and the two condensing sections C of the body 110. That is, the first capillary structure 120 is disposed in every section of the body 110.

The second capillary structure 130 is also disposed inside the body 110, surrounds the first capillary structure 120 (as shown in FIG. 1B), attached to the pipe wall 112 of the body 110, and has a 2D structure. In some embodiments, the second capillary structure 130 may be a mesh structure, and be formed into a sheet (as shown in FIG. 2B). The structure of the second capillary structure 130 will be described in detail below. As shown in FIG. 1A, the second capillary structure 130 is located only at the evaporating section E. This is advantageous for enhancing the heat absorption efficiency of the evaporating section E and preserving the internal space of the body in the condensing section C.

FIG. 1B shows the internal structure of the heat pipe 100 in the evaporating section E and the condensing sections C when viewed in the axial direction A. The cross-sections on the left and right side of FIG. 1B are the cross-sections along the sectional line M2 and the sectional line M3 in FIG. 1A, respectively. The cross-section in the middle of FIG. 1B is the cross-section along the centerline M1 in FIG. 1A.

As shown in FIG. 1B, the portions of the first capillary structure 120 that is located at the two condensing sections C only contact the pipe wall 112 on one side (the lower side in the drawing). As such, in addition to improving the heat dissipation efficiency on the contacted side, it also ensures that there is enough space for vapor to flow inside the tube in the condensing section C. Also, the portion of the first capillary structure 120 that is located at the evaporating section E contacts the pipe wall 112 on one side as well, in order to improve the heat dissipation efficiency.

As shown in FIG. 1B, in the evaporating section E, the second capillary structure 130 surrounds the first capillary structure 120 and is attached to the pipe wall 112. In some embodiments, the length of the second capillary structure 130 extending along the pipe wall 112 (the length L1 shown in FIG. 2B) is about three quarters of the circumference of the cross-section of the body 110 in a direction perpendicular to the axial direction A (such as the cross-section shown in the middle of FIG. 1B). As such, it effectively reduces thermal resistance and maximizes heat transfer in a limited space.

Referring to FIG. 2A to FIG. 2C and FIG. 5 to FIG. 6, FIG. 2A shows a schematic view of the position of the heat pipe 100 relative to the heat source 200, in accordance to some embodiments of the present disclosure; FIG. 2B shows a schematic view of the connection between the first capillary structure 120 and the second capillary structure 130, in accordance to some embodiments of the present disclosure; FIG. 2C shows a schematic view of the connection between the first capillary structure 120 and the second capillary structure 130′, in accordance to other embodiments of the present disclosure. The structures shown in FIG. 2B and FIG. 2C are suitable for the heat pipe 100 shown in FIG. 2A. FIG. 5 shows a schematic view of the connection between the first capillary structure 120 and the second capillary structure 130′ outside the body 110, in accordance to other embodiments of the present disclosure; FIG. 6 shows a schematic view of the configuration of the first capillary structure 120 and the second capillary structure 130′ inside the body 110, in accordance to other embodiments of the present disclosure.

In some embodiments, the heat source 200 is located substantially in the middle of the heat pipe 100. The heat pipes 100 shown in FIG. 2A and FIG. 6 both have bended structure that corresponds to the heat source 200. However, the shape of the heat pipe 100 is not limited thereto. It depends on actual needs. In FIG. 2A to FIG. 2C, the section of the heat pipe 100 that corresponds to the heat source 200 is the evaporating section E, the sections that do not correspond to the heat source 200 are the two condensing sections C.

In some embodiments, the first capillary structure 120 and the second capillary structure 130 are bonded together outside the body 110, and then disposed inside the hollow structure 111. For example, FIG. 2B shows the first capillary structure 120 and the second capillary structure 130 before they are disposed inside the body 110. At this time, the second capillary structure 130 is simply fixed onto the first capillary structure 120. As shown in FIG. 2B, the second capillary structure 130 may have an opening 135. The first capillary structure 120 is exposed from the opening 135. After disposing the first capillary structure 120 and the second capillary structure 130 inside the hollow structure 111, the exposed portion of the first capillary structure 120 is in contact with the pipe wall 112 (as shown in FIG. 1B) to improve heat dissipation efficiency.

In some embodiments, the length of the opening 135 of the second capillary structure 130 in the axial direction A (FIG. 1A) corresponds to the length of the heat source 200. For example, in FIG. 2B, the length L2 of the opening 135 corresponds to the length L5 of the heat source 200. That is, the length of the opening 135 of the second capillary structure 130 depends on the length of the heat source. It can be adjusted according to actual requirements, thereby enhancing the compatibility of the heat pipe 100.

In some embodiments, the width of the opening 135 of the second capillary structure 130 in the direction perpendicular to the axial direction A (FIG. 1A) is greater than the diameter of the first capillary structure 120. For example, in FIG. 2B, the width W of the opening 135 is greater than the diameter D of the first capillary structure 120. As such, it ensures that the first capillary structure 120 has a sufficient area that is exposed from the opening 135. This effectively reduces thermal resistance.

Another embodiment is shown in FIG. 2C and FIG. 5. In this embodiment, the second capillary structure 130′ has different structure than the second capillary structure 130 in FIG. 2B. Compared with the second capillary structure 130, the second capillary structure 130′ further includes a supporting portion 136 that is disposed at the middle portion of the opening 135, dividing the opening 135 into a first opening 137 and a second opening 138. Similar to the opening 135 of the second capillary structure 130, the first capillary structure 120 can also be exposed from the first opening 137 and the second opening 138 of the second capillary structure 130′.

FIG. 5 shows the first capillary structure 120 and the second capillary structure 130′ before they are disposed inside the body 110. An operator may fix the first capillary structure 120 and the second capillary structure 130′ together beforehand, and then set both of them into the body 110. Specifically, as shown in FIG. 5, the operator may pass the first capillary structure 120 through the first opening 137 of the second capillary structure 130′ from bottom to top, around the supporting portion 136, and then through the second opening 138 from top to bottom. As such, the bond between the first capillary structure 120 and the second capillary structure 130′ may be strengthened. They can be effectively secured, and their stability is improved.

After disposing the first capillary structure 120 and the second capillary structure 130′ inside the body 110, to secure the second capillary structure 130′, the upper and lower ends of the sheet-like second capillary structure 130′ are joined together, so that it adheres to the pipe wall 112. Specifically, the connecting points P shown in FIG. 2B is the joint of the second capillary structure 130. The operator may surround the first capillary structure 120 with the second capillary structure 130 so that the connecting points P on the upper and lower ends are connected. The connecting point P shown in FIG. 1B is where the two connecting points P in FIG. 2B overlap. The second capillary structure 130′ is joined using a similar method.

The state of the first capillary structure 120 and the second capillary structure 130′ after they are disposed inside the body 110 is shown in FIG. 6. FIG. 6 shows the state when the body 110 is cut open and lifted upward. The upper half of FIG. 6 shows the body 110 (only the pipe wall 112), and the lower half shows the first capillary structure 120 and second capillary structure 130′ disposed inside the body 110. As shown in FIG. 6, the first capillary structure 120 may be exposed from the first opening 137 and the second opening 138, being in contact with the pipe wall 112 above, and reducing thermal resistance to increase maximum heat transfer.

In addition, in the embodiment shown in FIG. 2C, in the axial direction A (FIG. 1A), the length of the first opening 137 and the length of the second opening 138 are the same. The total length of the first opening 137 and the second opening 138 may correspond to the length L5 of the heat source 200 (FIG. 2A).

In the embodiments shown in FIG. 2A to FIG. 2C, the two condensing sections C, the first capillary structure 120 and the second capillary structure 130 (or the second capillary structure 130′) are all symmetrical to the centerline (such as the centerline M1 shown in FIG. 1A) of the evaporating section E. The symmetrical structure has the advantage that the temperature difference between the two ends of the heat pipe 100 is small.

Referring to FIG. 3A to FIG. 3C, FIG. 3A shows a schematic view of the position of the heat pipe 100 relative to the first heat source 201 and the second heat source 202, in accordance to other embodiments of the present disclosure; FIG. 3B shows a schematic view of the connection between the first capillary structure 120 and the second capillary structure 130, in accordance to some embodiments of the present disclosure; FIG. 3C shows a schematic view of the connection between the first capillary structure 120 and the second capillary structure 130″, in accordance to yet other embodiments of the present disclosure. The structures shown in FIG. 3B and FIG. 3C are suitable for the heat pipe 100 shown in FIG. 3A.

The embodiments shown in FIG. 3A to FIG. 3C are similar to the embodiments shown in FIG. 2A to FIG. 2C. One of the differences is that a plurality of heat sources, rather than a single heat source, are included in FIG. 3A.

In some embodiments, the evaporating section E of the heat pipe 100 may correspond to a plurality of heat sources, such as the first heat source 201 and the second heat source 202 shown in FIG. 3A. In this case, the length of the opening 135 of the second capillary structure 130 shown in FIG. 3B in the axial direction A (FIG. 1A) may correspond to the sum of lengths of the plurality of heat sources (such as the sum of the length L6 of the first heat source 201 and the length L7 of the second heat source 202).

Another embodiment is shown in FIG. 3C. In this embodiment, the second capillary structure 130″ has a different structure than the second capillary structure 130′ in FIG. 2C. Compared with the second capillary structure 130′, although the second capillary structure 130″ also has a supporting portion 136, a first opening 137, and a second opening 138, the first opening 137 and the second opening 138 of the second capillary structure 130″ have different lengths in the axial direction (FIG. 1A) that correspond to lengths of different heat sources. For example, as shown in FIG. 3A and FIG. 3C, the length L3 of the first opening 137 of the second capillary structure 130″ corresponds to the length L6 of the first heat source 201, and the length LA of the second opening 138 corresponds to the length L7 of the second heat source 202. However, the term “correspond” does not mean that length L3 equals length L6, and length LA equals length L7. Rather, it means the length L3 of the first opening 137 may be greater than the length LA of the second opening 138 when the length L6 of the first heat source 201 is greater than the length L7 of the second heat source 202, and vice versa. Therefore, by disposing openings with adjustable lengths, the compatibility of the second capillary structure 130 with different heat sources is further improved.

In addition, although not shown, in other embodiments, the second capillary structure 130 may also include a plurality of supporting portions 136 so that the opening 135 is separated into more than two openings. This, in addition to further enhancing the bonding between the first capillary structure 120 and the second capillary structure 130, may also be adapted to different configurations or numbers of heat sources.

FIG. 4 is a broken line graph showing the effect of different capillary structures on the maximum heat transfer (Qmax). As shown, the maximum heat transfers achieved by three capillary structures are shown. The “mesh “0”” shown in the figure represents a capillary structure without a second capillary structure 130, which has the lowest maximum heat transfer. The “mesh “½”” shown in the figure represents a capillary structure with the second capillary structure 130 only attached to one half of the circumference of the pipe wall, which has the second highest maximum heat transfer. The “mesh “¾”” shown in the figure represents a capillary structure with the second capillary structure 130 attached to three quarters of the circumference of the pipe wall according to the present disclosure, which has the highest maximum heat transfer. As can be seen, the capillary structure according to the present disclosure can indeed enhance the maximum heat transfer in the heat pipe. According to some embodiments of the present disclosure, the maximum heat transfer of the heat pipe can be increased by up to 10%.

In addition, although FIGS. 5 and 6 show the first capillary structure 120 joined with the second capillary structure 130′, it should be understood that, in the embodiments shown in FIGS. 5 and 6, the second capillary structure 130 or the second capillary structure 130″ or other suitably sized mesh structures may also be utilized instead of the second capillary structure 130′ without limitation to the embodiments illustrated in the present disclosure.

In summary, the present disclosure provides a heat pipe 100 with a first capillary structure 120 and a second capillary structure 130 that are pre-joined outside the body 110. In addition to reducing process difficulty, saving material costs, and enhancing reliability, the design of the openings further reduces the thermal resistance from the evaporating section to the condensing section to increase the maximum heat transfer. In addition, the form of the opening of the second capillary structure 130 can be changed according to the actual configuration of the heat source, which effectively improves the compatibility with different heat sources. Moreover, the second capillary structure 130 of the present disclosure only needs to be located in the evaporating section E in the center of the heat pipe 100, which ensures that the condensing section C has enough space for heat transfer and enhances heat dissipation capability.

While the invention has been described by way of example and in terms of the preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.