TWI457528B - Plate type heat pipe - Google Patents

Description

Flat heat pipe

The present invention relates to a heat transfer device, and more particularly to a flat heat pipe.

The heat pipe is widely used because of its characteristics of ultra-quiet, high thermal conductivity, light weight, small size, simple structure and versatility. The basic structure is that the inner wall of the closed pipe is provided with a capillary structure layer which easily absorbs the working liquid, and the central portion thereof The space is in the state of the hollow body, and the working fluid is injected into the vacuum-tight closed pipe. The heat pipe is divided into an evaporation section and a condensation section according to the position of absorption and heat dissipation; the working principle is to transfer heat through the vapor-liquid two-phase change of the working liquid. First, the working liquid absorbs heat from the heat source in the evaporation section, causes the working liquid to evaporate and quickly passes the steam through the inner space of the tube, reaches the condensation section to cool and condense into a liquid and releases the heat energy, and the working liquid of the condensation section passes through the inner wall of the heat pipe. The capillary force provided by the capillary structure layer is returned to the evaporation section such that the heat pipe transfers heat through a continuous phase change of thermal energy circulation.

At present, the capillary structure in the heat pipe is usually a single type of capillary structure, and the heat pipe of the single type capillary structure has a capillary structure in which the condensed liquid flows back in the condensation section, and the heat pipe is used in the same position as the heat source. The maximum heat flux density that can be tolerated locally is almost uniform, and it is not possible to have both a small liquid reflux resistance and a large capillary force. To this end, the industry uses a multi-layer composite capillary structure to enhance the capillary force, and this arrangement reduces the flow space of the gaseous working medium inside the heat pipe, especially in the case where the heat pipe is flattened to a thin thickness. Will affect it Thermal conductivity.

In view of this, it is necessary to provide a flat heat pipe that takes into account a large capillary force and a large gaseous working medium flow space.

A flat heat pipe includes a sealed casing, a cavity formed in the casing, and a working medium filled in the cavity. The flat heat pipe has an evaporation section and a condensation section, and the casing has a first portion a capillary structure and a second capillary structure connected to the first capillary structure, the first capillary structure being attached to a portion of the inner wall of the evaporation section and longitudinally spaced apart from the condensation section, the second capillary structure being disposed on the housing The axial position is extended along the evaporation section of the flat heat pipe to the condensation section.

Compared with the prior art, the flat heat pipe is combined with the second capillary structure and the first capillary structure is only disposed on a part of the inner wall of the evaporation section, and the second capillary structure is disposed on the casing. The position of the axial center extends along the evaporation section of the flat heat pipe to the condensation section thereof, so that the flat heat pipe has a small liquid return resistance and a large capillary force, and the capillary force of the flat heat pipe near the heat source is improved, and It can ensure that the internal cavity of the flat heat pipe has a large space to prevent the flow space of the gaseous working medium from being insufficient due to the flattening.

100, 100a‧‧‧flat heat pipe

10‧‧‧shell

20‧‧‧Working media

30‧‧‧First capillary structure

40‧‧‧Second capillary structure

50‧‧‧ cavity

110‧‧‧Evaporation section

120‧‧‧Condensation section

101‧‧‧ bottom wall

103‧‧‧ top wall

105‧‧‧Left wall

107‧‧‧ right wall

301, 301a‧‧

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic axial cross-sectional view of a first embodiment of a flat heat pipe of the present invention.

Figure 2 is a schematic cross-sectional view of the flat heat pipe evaporation section of Figure 1.

Figure 3 is a schematic cross-sectional view showing a second embodiment of the evaporation section of the flat heat pipe of the present invention.

1 is a schematic axial cross-sectional view showing an embodiment of a flat heat pipe of the present invention. The flat heat The tube 100 includes a tubular housing 10, an appropriate amount of working medium 20 filled in the housing 10, and a first capillary structure 30 and a second capillary structure 40 attached to the inner wall of the housing 10. The flat heat pipe 100 has an evaporation section 110 at one end and a condensation section 120 at the other end.

Referring to FIG. 2 at the same time, the housing 10 has a flat cross section, and includes a bottom wall 101, a top wall 103 opposite to the bottom wall 101, and a left side wall connected between the bottom wall 101 and the top wall 103. 105 and right side wall 107. The casing 10 may be made of a metal material having good thermal conductivity such as copper or aluminum. A closed cavity 50 is formed in the housing 10, and the cavity 50 is typically evacuated or nearly vacuumed to facilitate thermal evaporation of the working medium 20. The working medium 20 may be a liquid having a higher latent heat such as water, alcohol, ammonia, or a mixture thereof.

The first capillary structure 30 is attached to a portion of the inner wall of the evaporation section 110 and longitudinally spaced apart from the condensation section 120. In this embodiment, the first capillary structure 30 is a sintered capillary structure attached to the inner surfaces of the top wall 103, the bottom wall 101 and the right side wall 107 of the evaporation section 110, and on the inner surface of the left side wall 105. The first capillary structure 30 is not provided, that is, the first capillary structure 30 forms an opening 301 at the left side wall 105. The second capillary structure 40 extends from the evaporation section 110 to the condensation section 120 along the axial line of the flat heat pipe 100, and is fixedly coupled to both ends of the flat heat pipe 4100. The second capillary structure 40 abuts against the inner wall of the upper and lower sides of the first capillary structure 30 at the position of the evaporation section 110, and is spaced apart from the inner wall of the casing 10 at the position of the condensation section 10. The second capillary structure 40 has an elongated hollow tubular shape. Inside the hollow tubular shape, a gas flow passage 401 through which steam can pass is formed, and a plurality of fine pores are formed in the wall portion. In this embodiment, the second capillary structure 40 is a wire mesh capillary structure woven from a wire made of a material such as copper or stainless steel. The second capillary structure 40 abuts within the first capillary structure 30 to enhance the tightness of the second capillary structure 40 to the inner wall of the housing 10. Since the flat heat pipe 100 employs a sintered first capillary structure 30 and a wire mesh second capillary structure The combination of 40, and the first capillary structure 30 is only disposed on a portion of the inner wall of the evaporation section 110, and the second capillary structure 40 extends along the axis of the flat heat pipe 100, so that the flat heat pipe 100 has a small liquid reflux resistance and The larger capillary force increases the capillary force of the flat heat pipe 100 near the heat source, enhances the thermal conductivity, and ensures that the internal cavity 50 of the flat heat pipe 100 has a large space to prevent the gaseous working medium from being flattened. Insufficient flow space.

3 is a longitudinal cross-sectional view of the evaporation section of the second embodiment of the flat heat pipe 100 of the present invention. The flat heat pipe 100a of the present embodiment has substantially the same structure as the flat heat pipe 100 of the first embodiment, and the difference is that the first A capillary structure 30a is attached to the bottom wall 101, the left side wall 105, the right side wall 107 and a portion of the top wall 103 of the housing, that is, the opening 301a is correspondingly disposed at the top wall 103c of the flat heat pipe 100a.

In a specific implementation, the number and arrangement positions of the openings 301 and 301a on the first capillary structure 30, 30a are not limited to the above embodiment, and one opening 301, 301a may be provided, or two or more may be provided. The opening 301, 301a, the opening 301, 301a may be disposed corresponding to the left side wall 105, or may be corresponding to the right side wall 107, as long as the first capillary structure 30, 30a must be provided for the inner wall of the evaporation section 110 corresponding to the heat source position. In addition, the other inner wall of the evaporation section 110 may be appropriately changed depending on the situation. The type of the first capillary structure 30, 30a and the second capillary structure 40 is not limited to the above embodiment. The first capillary structure 30, 30a may be a sintered type, or may be a wire mesh type, and the second capillary structure 40 It can be wire mesh or fiber bundle or powder sintered. When the first capillary structure 30, 30a is a wire mesh capillary structure, the first capillary structure 30, 30a may be crimped into a cylindrical shape by a wire having openings 301, 301a, and then attached to the evaporation section 110. On the inside wall.

In summary, the present invention complies with the requirements of the invention patent and submits a patent application according to law. but The above description is only the preferred embodiment of the present invention, and equivalent modifications or variations made by those skilled in the art will be included in the following claims.

100‧‧‧flat heat pipe

10‧‧‧shell

20‧‧‧Working media

30‧‧‧First capillary structure

40‧‧‧Second capillary structure

50‧‧‧ cavity

110‧‧‧Evaporation section

120‧‧‧Condensation section

Claims (9)

A flat heat pipe comprising a sealed casing, a cavity formed in the casing and a working medium filled in the cavity, the flat heat pipe having an evaporation section and a condensation section, the improvement being: the casing The utility model comprises a bottom wall, a top wall opposite to the bottom wall and two side walls connected between the top wall and the bottom wall, wherein the housing is provided with a first capillary structure and a second capillary connected to the first capillary structure a structure, the first capillary structure is attached from a bottom wall to a top wall via a side wall and attached to a portion of the inner wall of the evaporation section and longitudinally spaced apart from the condensation section, so that the evaporation section is not provided with the first capillary structure An opening is formed between the inner wall and the first capillary structure to communicate with the cavity, and the second capillary structure is disposed at an axial position of the housing and extends along the evaporation section of the flat heat pipe to the condensation section. The flat heat pipe according to claim 1, wherein the first capillary structure is disposed only on a bottom wall, a top wall and a side wall of the evaporation section, and the first capillary structure is not disposed on the other side wall. The flat heat pipe of claim 1, wherein the first capillary structure is provided with an opening in a top wall or a side wall of the evaporation section. The flat heat pipe according to any one of claims 1 to 3, wherein the second capillary structure is fixedly coupled to both ends of the flat heat pipe. The flat heat pipe of claim 4, wherein the second capillary structure abuts against an inner wall of the first capillary structure at an evaporation section of the heat pipe, and is spaced apart from an inner wall of the casing at a position of the condensation section open. The flat heat pipe of claim 1, wherein the second capillary structure is disposed at an axial position of the heat pipe. The flat heat pipe according to claim 1, wherein the first capillary structure is a sintered capillary structure, and the second capillary structure is a wire mesh capillary structure. The flat heat pipe according to claim 1, wherein the first capillary structure is a wire mesh capillary structure, the first capillary structure is a sintered capillary structure, and the first capillary structure is provided thereon The open screen is crimped in a cylindrical shape and attached to the inner wall of the evaporation section. The flat heat pipe of claim 1, wherein the working medium is water, alcohol, ammonia, and a mixture thereof.