Heat dissipation system

Abstract

A heat dissipation system comprises a printed circuit board and at least a heat dissipation device mounted on the printed circuit board for dissipating heat generated by an electronic member mounted on the printed circuit board. The at least a heat dissipation device comprises a base, a plurality of fins extending upwardly from the base and an air guiding member located at a corner of the base. These fins are spaced from each other to define a plurality of heat exchange passages. Non-fins are disposed at a side of the base to define a cooling air passage. The cooling air passage is parallel to the heat exchange passages of the fins. The air guiding member is located in the cooling air passage for controlling open and close of the cooling air passage.

1 . A heat dissipation system comprising:
 a printed circuit board;   at least a heat dissipation device mounted on the printed circuit board and comprising:
 a base secured to the printed circuit board and adapted for engaging an electronic member mounted on the printed circuit board; 
 a plurality of fins extending upwardly from a top face of the base, the fins defining a plurality of heat exchange passages therebetween; 
 a cooling air passage defined over the top face of the base, located beside the fins and being parallel to the heat exchange passages of the fins; and 
 an air guiding member located in the cooling air passage for controlling open and close of the cooling air passage to enable airflow to flow through the cooling air passage, or block the airflow from flowing through the cooling air passage. 
   
   
   
       2 . The heat dissipation system as claimed in  claim 1 , wherein the air guiding member comprises a holder secured on the base, a body pivotally engaging a top of the holder, and a wing integrally extending from an outer surface of the body. 
   
   
       3 . The heat dissipation system as claimed in  claim 2  further comprising a fastener securing the holder of the air guiding member on the base for preventing the holder from rotating with respect to the base. 
   
   
       4 . The heat dissipation system as claimed in  claim 3 , wherein the fastener comprises a bolt extending through the holder of the air guiding member and a spring sandwiched between the holder and an upper head of the bolt. 
   
   
       5 . The heat dissipation system as claimed in  claim 2 , wherein the body has a tie-in at a bottom end thereof, the tie-in protruding two clasps at two opposite sides thereof, the holder defining four evenly spaced slots in an inner wall thereof, the clasps of the tie-in clasping with corresponding two of the four slots for positioning the wing of the air guiding member at one of positions for controlling open and close of the cooling air passage. 
   
   
       6 . The heat dissipation system as claimed in  claim 5 , wherein the slots of the holder of the air guiding member each have a V-shaped configuration. 
   
   
       7 . The heat dissipation system as claimed in  claim 6 , wherein two adjacent ones of the four slots of the holder each have an angle not larger than 90 degrees, the other two adjacent ones of the four slots each having an angle larger than 90 degrees, when one of the clasps of the body is blocked in one of the two adjacent ones of the four slots having an angle not larger than 90 degrees, the wing of the air guiding member being positioned to be parallel to the cooling air passage, when the one of the clasps is blocked in the other one of the two adjacent ones of the four slots having an angle not larger than 90 degrees, the wing being positioned to be perpendicular to the cooling air passage. 
   
   
       8 . The heat dissipation system as claimed in  claim 1 , wherein non-fins are located at a side of the base to define a blank region for forming the cooling air passage. 
   
   
       9 . The heat dissipation system as claimed in  claim 1 , wherein a width of the cooling air passage is larger than that of the heat exchange passage. 
   
   
       10 . A heat dissipation system for dissipating heat generated by two electronic members in a computer system comprising:
 an airflow path in the computer system;   a first heat dissipation device located in the airflow path and near an intake of the airflow path, the first heat dissipation device comprising a first heat exchange passage and a first cooling air passage being parallel to the first heat exchange passage; and   a second heat dissipation device located in the airflow path and away from the intake of the airflow path, the second heat dissipation device comprising a second heat exchange passage and a second cooling air passage, the second heat exchange passage and the second cooling air passage being parallel to the first heat exchange passage of the first heat dissipation device;   wherein the first cooling air passage of the first heat dissipation device is open, and the second cooling air passage of the second heat dissipation device is close.   
   
   
       11 . The heat dissipation system as claimed in  claim 10 , wherein the first heat dissipation device is the same as the second heat dissipation device. 
   
   
       12 . The heat dissipation system as claimed in  claim 11 , wherein the first cooling air passage of the first heat dissipation device faces the second heat exchange passage of the second heat dissipation device. 
   
   
       13 . The heat dissipation system as claimed in  claim 11 , wherein the first and second heat dissipation devices each comprise a base and a plurality of parallel spaced fins extending upwardly from the base, the fins of the first heat dissipation device defining the first heat exchange passage therebetween, the fins of the second dissipation device defining the second heat exchange passage therebetween, non-fins being located at a side of the base, the non-fins located at a side of the base of the first heat dissipation device forming the first cooling air passage, the non-fins located at a side of the base of the second dissipation device forming the second cooling air passage. 
   
   
       14 . The heat dissipation system as claimed in  claim 13 , wherein the first and second heat dissipation devices each further comprise an air guiding member, the air guiding member comprising a holder secured on the base, a body pivotally engaging a top of the holder, and a wing extending from an outer surface thereof. 
   
   
       15 . The heat dissipation system as claimed in  claim 14 , wherein the wing of the first heat dissipation device is located near the intake of the airflow path and is parallel to the first cooling air passage of the first heat dissipation device, the wing of the second heat dissipation device being perpendicular to the second cooling air passage of the second heat dissipation device.