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1. Field of the Invention
The present invention generally relates to a cooling device using a liquid, such as water, as coolant, for cooling particularly a computer system, and in particular to a coolant tray of the cooling device that is positionable on a heat generating device of the computer system for effectively and efficiently removing heat from the heat generating device with the coolant flowing through an internal channel of the coolant tray.
2. The Related Art
Conventionally, a heat sink, such as an aluminum extrusion having spaced fins, is positioned on and in physical engagement with a heat generating device, such as a central processing unit, of a computer system for removing heat from and maintaining proper operation temperature of the central processing unit. Such a heat sink is an air-cooling device that removes heat from the central processing unit with airflows. However, such an aluminum extrusion heat sink is subject to limitation in removing a great amount of heat.
A water based cooling device is thus employed in computer systems of high speed that generate a great amount of heat to replace the conventional aluminum extrusion heat sink. In addition to the enhanced capacity of heat removal, the liquid based cooling device is advantageous in small size, which is of particular importance in the current trend of miniaturization of the computer industry, and is thus particularly suitable for portable computers, which is of a much smaller size than a fixed computer, and often requiring much higher heat removal rate.
A liquid based cooling device for computers is comprised of a coolant tray positionable on and in physical contact with a heat generating device of the computer, such as a central processing unit, and a radiator spaced from the coolant tray and often located in surroundings having temperature lower than that of the central processing unit. A coolant pump is arranged between the coolant tray and the radiator for circulating a liquid coolant, such as water, between the coolant tray and the radiator, which transfers the heat absorbed by the coolant flowing through the coolant tray to the radiator at which the heat is dissipated into the surroundings.
Conduits, such as pipes, are connected among the coolant pump, the coolant tray, and the radiator to complete a circulation loop of the coolant. In practice, at least three pipes are required, respectively for connection between the coolant tray and the coolant pump, connection between the coolant pump and the radiator, and connection between the coolant tray and the radiator. Such an arrangement makes the assembling of the cooling device complicated for there are a great number of parts, including those pipes, which must be individually coupled to the coolant tray, the coolant pump, and the radiator. In addition, such a great number of the parts makes the cooling device expensive in manufacturing and bulky in size, which is against the trend of down-cost and miniaturization of the computer or electronic industry and is thus not suitable for applications in portable devices.
Thus, the present invention is aimed to provide a coolant tray of a liquid based cooling device that overcomes, or at least alleviates, the above-discussed problems.
A primary objective of the present invention is to provide a liquid based cooling device comprising a coolant tray, a pump, and a radiator, wherein the pump and the coolant tray are combined together as a single unitary device in order to simplify the structure and manufacturing of the liquid based cooling device.
To achieve the above objective, in accordance with the present invention, a coolant tray for a liquid based cooling device is provided. The liquid based cooling device comprises a pump for driving a coolant through the coolant tray that is positionable on a heat generating device and a radiator that dissipates the heat into the surrounding. The coolant tray comprises a housing on which coolant inlet and outlet are formed for receiving the coolant from the pump and discharging the coolant to the radiator. The coolant tray also forms a recess in which a thermally conductive base forming a coolant channel is received in a liquid tight manner. The pump comprises a casing in which coolant inlet and outlet are formed. The inlet of the coolant tray is integrally connected to the outlet of the pump and the housing of the coolant tray and the casing of the pump are integrally formed with each other with an integrally formed conduit connected therebetween.
Since three parts, including the housing of the coolant tray, the casing of the pump, and the conduit connected between the housing and the casing are integrally formed together with the same material as a single unitary member, the structure and manufacturing of the cooling device is simplified and the overall size reduced, making the cooling device in accordance with the present invention particularly suitable for portable electronic devices that have a very limited interior space for accommodation of the cooling device, while requiring efficient removal of heat.
The present invention will be apparent to those skilled in the art by reading the following description of a preferred embodiment thereof, with reference to the attached drawings, in which:
FIG. 1 is a perspective view of a liquid based cooling device in which a coolant tray constructed in accordance with the present invention is incorporated;
FIG. 2 is an exploded view of the coolant tray and a coolant pump in accordance with the present invention; and
FIG. 3 is a cross-sectional view of a combined unitary device of the coolant tray and the coolant pump in accordance with the present invention.
With reference to the drawings and in particular to FIG. 1, a liquid based cooling device is shown. The cooling device is operated with a liquid coolant, such as water, for cooling for example an electronic device 29, such as a computer central processing unit mounted on a circuit board 28 of the computer system (see FIG. 3), which generates heat that must be removed to maintain the temperature of the electronic device 29 within a proper range. The cooling device is comprised of a coolant tray 20 having a surface positionable on and in physical contact with the electronic device 29, a radiator 30 spaced from the coolant tray 20 and located in a low temperature surrounding, and a pump 10 connected to the radiator 30 and the coolant tray 20 by pipes to complete a circulation loop among the coolant tray 20, the pump 10, and the radiator 30. The pump 10 circulates a coolant between the coolant tray 20 and the radiator 30. Heat carried by the coolant to the radiator 30 is dissipated into the surrounding by natural convection and radiation. Preferably, a fan 40 is combined with the radiator 30 to induce force convection for more efficiently dissipating the heat into the surrounding.
Also referring to FIGS. 2 and 3, the pump 10 comprises a casing 11 defining an upper chamber 12 delimited by a side wall (not labeled) forming an outlet 13. The upper chamber 12 is closed by a lid 16 in which an inlet 17 is formed and in fluid communication with the upper chamber 12. A blade assembly comprised of a plurality of blades 15 extending from a hub to which a magnet 14 is attached. The blade assembly is rotatably fit over a shaft 19 extending in the upper chamber 12 to serve as a rotor of the pump 10.
The coolant tray 20 constructed in accordance with the present invention comprises a flat housing 21 having a top surface in which a coolant inlet 24 and a coolant outlet 25 are formed. The flat housing 11 has a bottom surface opposite to the top surface and defining a recess (not labeled and shown in FIG. 4) in which a base 22 is received in a liquid-tight manner. The base 22 is secured to the housing 21 by means of fasteners 26, such as bolts. The base 22 is made of thermally conductive materials, such as metal, to enhance heat transfer between the heat generating device 29 and the coolant.
The base 22 of the coolant tray 20 has a top received in the recess of the housing 21 and a bottom exposed for positionability on and tight contact with the central processing unit 29. The positioning of the coolant tray 20 on the central processing unit 29 can be secured by fasteners, such as bolts 27, tightened on the circuit board 28.
The top of the base 22 forms a coolant channel 23 having opposite ends (not labeled) respectively corresponding in position to and in fluid communication with the inlet and outlet 24, 25 of the housing 21 whereby the coolant flowing through the inlet 24 is allowed to enter an end of the channel 23, and then flowing along the channel 23 toward the other end at which the coolant is allowed to discharge through the outlet 25.
The coolant outlet 25 of the coolant tray 20 is connected by a pipe 50 to the radiator 30 where heat carried by the coolant is dissipated to the surrounding. The coolant flowing through the radiator 30 is guided to the pump 10 through the coolant inlet 17 that is connected to the radiator 30. A pipe 18 is connected between the coolant outlet 13 of the pump 10 and the coolant inlet 24 of the coolant tray 20, guiding the coolant that is driven by the pump 10, into the coolant tray 20.
The coolant inlet 24 of the coolant tray 20 is connected by the pipe 18 to the coolant outlet 13 of the upper chamber 12 of the pump 10. The pipe 18 is integrated with the housing 21 of the coolant tray 20 and the casing 11 of the pump 10. In other words, the housing 21 of the coolant tray 20, the pipe 18, and the casing 11 of the pump 10 are integrally formed together as a unitary member made with the same material. Thus, three parts, including the housing 21 of the coolant tray 20, the pipe 18, and the casing 11 of the pump 10, are combined together as a single unitary part. In addition, the couplings between the pipe 18 and the coolant inlet 24 of the coolant tray 20 and between the pipe 18 and the coolant outlet 13 of the pump 10 are eliminated. Consequently, the number of parts of the cooling device is reduced to quite an extent and the manufacturing thereof is substantially simplified.
In addition, due to the integration of the housing 21 of the coolant tray 20 and the casing 11 of the pump 10, the pump 10 and the coolant tray 20 are fixed with respect to each other and the spatial relationship is fixed. The distance between the pump 10 and the coolant tray 20 can be minimized, whereby the amount of space occupied by the cooling device is minimized. This makes the cooling device a perfect choice for portable electronic devices that have a very limited interior space for accommodation of the cooling device.
Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.