US20030121646A1 - Heat pipe - Google Patents

Abstract

A heat pipe has a tube with an open end and a closed end. Copper powder is sintered onto an inner surface of the tube to form a porous lining. Air is then evacuated to form a substantially vacuum state in the tube from the open end. Working fluid is added into the tube and the open end is sealed afterwards. In operation, heat generated by an electronic component is absorbed by the heat pipe and forms a heated region in the tube. Working fluid in the heated region evaporates and travels to a cool region and condenses. The working fluid is then driven by capillary force to circulate back to the heat region through the porous lining. This thermodynamic cycle continues as the heat is transferred and dissipated throughout the heat pipe in an extremely high efficiency.

Description

BACKGROUND OF THE INVENTIONS
• 1. Field of the Invention [0001]
• The present invention relates to a heat pipe, and more particularly to a heat pipe used to efficiently transfer heat throughout the heat pipe for cooling an electronic component. [0002]
• 2. Description of Related Art [0003]
• A heat pipe is an efficient heat transfer device commonly used for cooling an electronic component generating undesired heat, the component being typically of a portable computer or a personal digital assistant (PDA). With reference to FIGS. 4 and 5, a conventional heat pipe is shown and has a tube ([0004] 70). The tube (70) further has a closed end (72) and a sealed end (74), wherein the sealed end (74) is originally an open end and sealed after the tube (70) has been evacuated to a substantially vacuum state. In operation, the tube (70) is attached to the electronic component and heat generated thereby is transferred throughout the heat pipe so as to cool the component.
• However, with rapid improvements of the electronic technology, the heat generated by the electronic component has increased considerably, and therefore excess heat has become a major problem that needs to be overcome. That is, the conventional heat pipe can no longer meet today's heat dissipation requirements. [0005]
• Therefore, the present invention intends to provide an improved heat pipe to overcome the mentioned heat-generation problem. [0006]
SUMMARY OF THE INVENTION
• The objective of the present invention is to provide a heat pipe having a tube. The tube is filled with working fluid and copper powder is sintered onto an inner surface of the tube such that the heat pipe has an extremely high heat-dissipating efficiency. [0007]
• Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.[0008]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIGS. [0009] 1A-D are a series of schematic, cross-sectional views showing the steps of producing a heat pipe in accordance with the present invention;
• FIG. 2 is a perspective view of the heat pipe of the present invention; [0010]
• FIG. 3 is a cross-sectional view of the heat pipe taken along line [0011] 3-3 of FIG. 2;
• FIG. 4 is a perspective view of a conventional heat pipe; and [0012]
• FIG. 5 is a cross-sectional view of the conventional heat pipe taken along line [0013] 5-5 of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• With reference to FIGS. [0014] 1A-D, to produce a heat pipe in accordance with the present invention, a tube (10) preferably made of copper is first prepared as shown in FIG. 1A. The tube (10) has an open end (12) and a closed end (14). Second, a copper rod (20) is inserted into the tube (10) via the open end (12) and the area between the interior of the tube (10) and the copper rod (20) is filled with copper powder as shown in FIG. 1B. Then the tube (10) together with the copper rod (20) and the copper powder are heated so that the copper powder is sintered onto an inner surface of the tube (10) to form a porous lining. Third, the copper rod (20) is withdrawn from the tube (10), thereby forming a center hole (35) defined by the copper powder as shown in FIG. 1C. Fourth, air in the tube (10) is evacuated until a substantial vacuum state is reached. Working fluid such as pure water is further added into the tube (10) as shown in FIG. 1D and the open end (12) is tightly sealed to form a sealed end (12′) as shown in FIG. 2.
• In operation, the heat pipe is attached to a component generating undesired heat of an electronic device such as a portable computer or a personal digital assistant (PDA). Heat generated by the component heats a region of the tube ([0015] 10) and evaporates the working fluid so that vapor is created in that heated region. The vapor then travels in the tube (10) to a cool region and condenses to carry the heat from the heated region to the cool region. The working fluid further circulates back to the heated region through the porous lining of copper powder by capillary force. This thermodynamic cycle repeats as the heat is transferred and dissipated throughout the heat pipe in an extremely high efficiency.
• While this invention has been particularly shown and described with references to the preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. [0016]

Claims (1)

What is claimed is:

1. A heat pipe comprising:

a vacuum tube having an open end and a sealed end;

copper powder sintered onto an inner surface of the vacuum tube to form a porous lining; and

working fluid contained in the vacuum tube,

whereby the working fluid is evaporated in a heated region of the heat pipe and travels in the vacuum tube in a gas phase and condenses in a cool region of the heat pipe, the working fluid then circulates back to the heated region by a capillary force via the porous lining such that a thermodynamic cycle is formed to transfer heat throughout the heat pipe.

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