Patent Publication Number: US-2012044634-A1

Title: Heat dissipation apparatus

Description:
BACKGROUND 
     1. Technical Field 
     The disclosure generally relates to a heat dissipation apparatus, especially to a heat dissipation apparatus used to dissipate heat from memory chips in a computer. 
     2. Description of Related Art 
     All-in-One computers are desktop computers that combine the monitor into the same case as the CPU. A typical all-in-one computer includes a motherboard, a heat sink and a cooling fan. A plurality of heat sources (e.g., CPU, north bridge chip, south bridge chip, hard disc, memory chip) are attached on the motherboard. In order to save space in the All-in-One computers, the memory chips are positioned parallel on the motherboard. Cold airflow enters the computer, passes through an air channel between the hard disc and the motherboard, and dissipates heat from the hard disc, the CUP and other heat sources. In addition, the heated airflow is then sucked out from the computer by a plurality of fans. The cold airflow only flows through a top of the memory chips. A special fan for the memory chips is needed and the typical heat dissipation apparatus has low heat dissipation efficiency. 
     Therefore there is a need for improvement in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments can be better understood with references to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an exploded, isometric view of an embodiment of a heat dissipation apparatus. 
         FIG. 2  is an assembled view of an embodiment of the heat dissipation apparatus of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
     Referring to  FIG. 1 , an embodiment of a heat dissipation apparatus includes a computer case  10 . The computer case  10  includes a base plate  11 , a first side plates  12  and a second side plate  13 , a front plate  14  and a back plate  15 . The first and second side plates  12 ,  13 , the front plate  14  and the back plate  15  are perpendicular to the base plate  11 . 
     The base plate  11  includes a motherboard  20  positioned thereon. The motherboard  20  includes a first heat source (not shown) thereon. A heat sink  21  is positioned on the first heat source and is in thermal contact with the first heat source. The heat sink  21  includes a plurality of fins  211 . A width of the fins  211  at two sides of the heat sink  21  is less than that of the fins  211  in the middle. The motherboard  20  includes a second heat source  22  positioned thereon at a first side of the heat sink  21 . The motherboard  20  includes an air duct  23  and a fan  24  positioned thereon at a second side of the heat sink  21 . An angle between the second heat source  22  and the base plate  11  is greater than 0 degrees and less than 90 degrees. The airflow from outside is sucked into the computer case  10 , and the airflow diagonally passes through the surface of the second heat source  22  to dissipate heat for the first heat source and the second heat source  22 . The front plate  14  defines a plurality of air inlet holes  141  that open towards the second heat source  22 . In one embodiment, the angle is 30 degrees; the second heat source  22  includes a first memory chip  221  and a second memory chip  222 ; and the first heat source is a CPU. 
     The air duct  23  includes an air inlet opening  231  and an air outlet opening  232 . The air inlet opening  231  opens towards the second side of the heat sink  21 . The air outlet opening  232  opens towards the fan  24 . The back plate  15  defines a plurality of air outlet holes  151  thereon. The plurality of air outlet holes  151  open towards the fan  24 . The airflow passing through the second heat source  22  and the heat sink  21  is blown out of the computer case  10  by the plurality of air outlet holes  151 . 
     When the computer is powered up, the fan  24  can rotate. The cool air from outside the computer case  10  is sucked into the computer case  10  by the fan  24  through the air inlet holes  141 . A speed of the cool airflow is accelerated when passing through the first and second memory chips  221 ,  222 , and the heat sink  21 . Some of the cool airflow diagonally passes through a bottom surface of the first memory chip  221  and a top surface of the second memory chip  222 . And some of the cool airflow passes through a top surface of the first memory chip  221  and a bottom surface of the second memory chip  222  through a gap between the first and second memory chips  221  and  222 . The cool air displaces the warm air heated by the first and second memory chips  221 ,  222  and the heat sink  21 . The warm air is blown out of the computer case  10  by the fan  24  through the air duct  23  and the air outlet holes  151 . 
     Using a software application called Icepak to simulate the efficiency of the heat dissipation system, the following results of one embodiment shown below were obtained. The simulated conditions are set to: initial ambient temperature 35 degrees Celsius. A power dissipation of the first heat source is 95 W. A power dissipation of the second heat source  22  is 20 W. The heat sink  21  has a dimension of 85.3 millimeter (mm)×81 mm×87.7 mm (length×width×height). The fan  24  has a dimension of 92 mm×92 mm×25 mm (length×width×height). A maximum air flow rate of the fan  24  is 35.32 cubic feet per minute (cfm). A rated speed of the fan  24  is 2000 revolutions per minute (rpm). A maximum static pressure of the fan  24  is 0.084 inch-H 2 O. The simulation according to the set conditions shows that the maximum temperature on the surfaces of the first and second memory chips  221 ,  222  is 71.9354 degrees Celsius when the heat dissipation apparatus of the disclosure. A threshold value of the temperature on the surfaces of the first and second memory chips  221 ,  222  is 85 degrees Celsius. The maximum temperature on the surfaces of the first and second memory chips  221 ,  222  is less than the threshold value. The fan for the first and second memory chips  221 ,  222  in the typical heat dissipation apparatus is not needed and heat dissipation efficiency is improved. 
     It is to be understood, however, that even though numerous characteristics and advantages have been set forth in the foregoing description of preferred embodiments, together with details of the structures and functions of the preferred embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.