Patent Application
20140138056
1. Field of the Invention
The present invention relates to heat pipe technology and more particularly, to a low-profile composite heat pipe that is formed of two flat pipe components and has low profile and uniform heat transfer characteristics.
2. Description of the Related Art
Various heat pipe designs have been disclosed for use in electronic products for quick transfer of waste heat. Following the market trend of the electronic industry toward a low profile design, the vertical installation space in an electronic device for heat pipe must be minimized. Thus, flat heat pipes are created. A conventional flat heat pipe may be made by making flow-guide grooves on the inside wall of a round pipe and then flatting the round pipe into a flat condition to reduce pipe height. Further, in order to comply with the arrangement of electronic components in an electronic product, or in order to comply with the demand for space arrangement in an electronic product, a heat pipe may be bent into a particular shape. However, bending a heat pipe into a particular shape can destruct the structure of the flow-guide grooves, lowering the heat transfer performance of the heat pipe. Further, employing an extrusion or roller ramming technique to make flow-guide grooves, the density of flow-guide grooves is limited, lowering the flow guide performance. Further, when flattening a curved heat pipe into a flat condition, if the wall is too thin or the flattening degree is too large, the flattening force can easily break the curved portion.
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a low-profile composite heat pipe, which has a low profile, and intersected or parallel flow-guide grooves located on the inside to enhance flowing of the internal working fluid.
To achieve this and other objects of the present invention, a heat pipe comprises a flat plate-like first pipe component shaped like a flat plat member and having flow-guide grooves located at the inner surface between two opposite ends thereof and a wick structure sintered on the surface of the flow-guide grooves, a flat plate-like second pipe component having flow-guide grooves located at the inner surface between two opposite ends thereof and a wick structure sintered on the surface of the flow-guide grooves, an enclosed cavity defined in between the first pipe component and the second pipe component and surrounded by the wick structures of the first and second pipe components, and a working fluid contained in the enclosed cavity.
Further, the first pipe component comprises at least one first curved potion disposed between two opposite ends thereof; the second pipe component comprises at least one second curved portion disposed between two opposite ends thereof corresponding to the at least one first curved portion of the first pipe component.
Referring to
The first pipe component 1 is a narrow, elongated, curved, hollow flat member, defining a plurality of curved portions 11. Further, the first pipe component 1 comprises a base wall 12, a plurality of flow-guide grooves 4 longitudinally formed inside the base wall 12 in a parallel manner between the two opposite ends thereof by means of extrusion or roller ramming, and an endless upright wall 13 perpendicularly extended around the border of the base wall 12. The second pipe component 2 is a narrow, elongated, curved, hollow flat member configured subject to the configuration of the first pipe component 1, defining a plurality of curved portions 21 corresponding to the curved portions 11 of the first pipe component 1 and flow-guide grooves 4 at one side thereof. Further, a wick structure 5 is formed on an inner surface of the endless upright wall 13 of the first pipe component 1 and flow-guide grooves 4 of the first pipe component 1 and second pipe component 2 by sintering.
The second pipe component 2 is covered on the first pipe component 1 and sealed thereto by welding or ultrasonic fusion bonding, and thus an enclosed cavity 3 is defined in between the first pipe component 1 and the second pipe component 2. After formation of the heat pipe 10, the cavity 3 is kept in an airtight condition. Further, before closing the second pipe component 2 on the first pipe component 1, a working fluid 6 is filled in the space surrounded by the base wall 12 and endless upright wall 13 of the first pipe component 1. After filling of the working fluid 6 in the first pipe component 1, the second pipe component 2 is covered on the first pipe component 1 and sealed thereto air-tightly.
In conclusion, the invention provides a low-profile composite heat pipe 10 that has the advantages and features as follows:
1. The low-profile composite heat pipe 10 is made by sealing a flat, elongated first pipe component 1 and a flat, elongated second pipe component 2 together, having a low profile characteristic.
2. The low-profile composite heat pipe 10 is made by sealing a flat, elongated first pipe component 1 and a flat, elongated second pipe component 2 together that are configured subject to the desired shape and processed by extrusion or roller ramming to provide flow-guide grooves 4 at the inner surface thereof. When the flat, elongated first pipe component 1 and the flat, elongated second pipe component 2 are bonded together, the flow-guide grooves 4 are kept intact for quick heat transfer. Further, by means of extrusion or roller ramming, a large amount of flow-guide grooves 4 can be densely made in the limited surface area of the flat, elongated first pipe component 1 and the flat, elongated second pipe component 2.
3. The low-profile composite heat pipe 10 is made by sealing a flat, elongated first pipe component 1 and a flat, elongated second pipe component 2 together. Thus, the desired flow-guide grooves 4 can be made at the flat, elongated first pipe component 1 and the flat, elongated second pipe component 2 before bonding, and can be kept intact after the flat, elongated second pipe component 2 are bonded together.
