Metal working – Method of mechanical manufacture – Heat exchanger or boiler making
Reexamination Certificate
2000-05-11
2001-05-29
Rosenbaum, Irene Cuda (Department: 3726)
Metal working
Method of mechanical manufacture
Heat exchanger or boiler making
C029S890030
Reexamination Certificate
active
06237223
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to the cooling of heat generating surfaces and objects. More specifically, the present invention relates to apparatuses for dissipating heat generated by such objects. In addition, the present invention relates to cooling of heat generating objects passively by use of a phase-change media without the use of external fans or devices to assist in cooling.
In industry, there are various parts and components that generate heat during operation. For example, in the electronics and computer industries, it is well known that computer components generate heat during operation. Various types of electronic device packages and integrated circuit chips, such as the PENTIUM central processing unit chip (CPU) manufactured by Intel Corporation and RAM (random access memory) chips are such devices that generate heat. These integrated circuit devices, particularly the CPU microprocessor chips, generate a great deal of heat during operation which must be removed to prevent adverse effects on operation of the system into which the device is installed. For example, a PENTIUM microprocessor, containing millions of transistors, is highly susceptible to overheating which could destroy the microprocessor device itself or other components proximal to the microprocessor.
There are a number of prior art methods to cool heat generating components and objects to avoid device failure and overheating, as discussed above- A block heat sink or heat spreader is commonly placed into communication with the heat generating surface of the object to dissipate the heat therefrom. Such a heat sink typically includes a base member with a number of individual cooling members, such as fins, posts or pins, to assist in the dissipation of heat. The geometry of the cooling members is designed to improve the surface area of the heat sink with the ambient air for optimal heat dissipation. The use of such fins, posts of pins in an optimal geometrical configuration greatly enhances heat dissipation compared to devices with no such additional cooling members, such as a flat heat spreader.
To further enhance air flow and resultant heat dissipation, fans and devices have been used, either internally or externally. However, these external devices consume power and have numerous moving parts. As a result, heat sink assemblies with active devices are subject to failure and are much less reliable than a device which is solely passive in nature.
It has been discovered that more efficient cooling of electronics can be obtained through the use of passive heat pipes which require no external power source and contain no moving parts. Generally, the heat pipe is in the form a vacuum-tight vessel in a particular geometric shape which is evacuated and partially filled with a working fluid. The heat pipe passively transfers heat from a heat source to a heat sink where heat is dissipated. As the heat is conducted into the heat pipe, the fluid is vaporized in an evaporator section creating a pressure gradient in the heat pipe. This forces the vapor to flow along the heat pipe to the condenser section, where the vaporized fluid is condensed and turned back to its fluid state by giving up its latent heat of vaporization. The working fluid is then returned to the evaporator section to repeat the process of removing the heat generated by the heat source. One method used to achieve cooling by use of a heat pipe places the evaporator section at the lower end and the condenser section at the upper end where the heat pipe is in a substantially vertical position. Once the working fluid has been condensed, the liquid flows by gravity back to the evaporator section. Internal wick structures may be used to assist liquid flow back to the evaporator section by capillary action to reduce the effect of gravity on the device.
In view of the foregoing, there is a demand for a heat sink assembly that is capable of dissipating heat. There is a demand for a passive heat sink assembly with no moving parts that can provide heat dissipation without the use of active components. In addition, there is a demand for a complete heat sink assembly that can provide greatly enhanced heat dissipation over prior art passive devices.
SUMMARY OF THE INVENTION
The present invention preserves the advantages of prior art heat dissipation, heat exchanger devices and heat pipes. In addition, it provides new advantages not found in currently available devices and overcomes many disadvantages of such currently available devices.
The invention is generally directed to the novel and unique phase change heat sink assembly with particular application in cooling heat generating components and objects. The heat sink assembly of the present invention enables the simple, easy and inexpensive assembly, use and maintenance of a heat dissipation device which is extremely reliable with, essentially, no maintenance during the life of the device. The assembly of the present invention has particular application in providing heat dissipation for electronic components which are particularly sensitive to overheating.
The phase change heat sink of the present invention includes a base member and a number of individual heat dissipating members. The base member is hollow and defines an evaporation chamber therein. A number of heat dissipating members are connected to the base member. Each of the heat dissipating members are substantially tubular in configuration with a closed end and an open end and defining respective condensation chambers therein. The open ends of the heat dissipating members are connected to the base member with the condensation chambers and are in fluid communication with the evaporation chamber. A heat transporting media resides in the base member which is movable into the condensation chambers upon application of heat to the base member. Heat is dissipated through the heat dissipating members. Further, the present invention preferably includes a wick structure within the base and individual heat dissipating members. The wick structure in the heat dissipating members assists, by capillary action, in returning condensate back to the base evaporator region. The present invention simultaneously provides both the advantages of a phase change heat pipe and the improved geometry of a heat sink to provide a greatly enhanced heat dissipating device.
It is therefore an object of the present invention to provide a method of forming a heat dissipating device that can provide enhanced heat dissipation for a heat generating component or object.
It is an object of the present invention to provide a method of forming a heat dissipating device that can provide enhanced heat dissipation passively without the use of active components.
It is a further object of the present invention to provide a method of forming a heat dissipating device that has no moving parts.
Another object of the present invention is to provide a method of forming a heat dissipating device that does not consume power.
It is a further object of the present invention to provide a method of forming a heat dissipating device that has the advantages of both a phase change heat pipe and the improved cooling member geometry of a heat sink.
Another object of present invention is to provide a method of forming a heat dissipation device that is a combination heat pipe and heat sink configuration that is substantially insensitive to gravity.
A further object of the present invention is to provide a method of forming a heat dissipation device that is inexpensive to manufacture.
Another object of the present invention is to provide a method of forming a heat dissipation device that has a thermal conductivity greater that conventional heat pipe and heat sink designs.
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patent: 5046553 (1991-09-01), Lindner
patent: 5213153 (1993-05-01), Itoh
patent: 5216580 (1993-06-01), Davidson et al.
patent: 52537
Barlow Josephs & Holmes, Ltd.
Chip Coolers, Inc.
Cuda Rosenbaum Irene
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