Thermosiphon with flexible boiler plate

Abstract

A thermosiphon cooling assembly includes a housing having a lower portion and an upper portion. A refrigerant is disposed in the lower portion for liquid-to-vapor transformation. A boiler plate defines an outer bottom wall of the housing for transferring heat from the electronic device to the refrigerant. This transfer of heat to the refrigerant leads to a liquid-to-vapor transformation and a pressure build up in the housing. The boiler plate is flexible for reacting with the electronic device in response to the pressure build up in the housing. The boiler plate includes an inflexible first area for overlying the electronic device and a flexible second area which surrounds the first area of the boiler plate. The second area has a thickness t 2 less than the thickness t, of the first area thus allowing the boiler plate to flex in the second area.

1 . A thermosiphon cooling assembly for cooling a flat electronic device disposed on a support and comprising; 
 a housing being hermetically sealed and defining a lower portion and an upper portion,    a refrigerant disposed in said lower portion of said housing for liquid-to-vapor transformation, and    a boiler plate defining an outer wall of said housing for transferring heat from the electronic device to said refrigerant for liquid-to-vapor transformation and a pressure build up in said housing,    said boiler plate being flexible for reacting with the electronic device in response to said pressure build up in said housing.    
   
   
       2 . An assembly as set forth in  claim 1  including a biasing mechanism for connection to the support to facilitate movement of said housing as said boiler plate reacts with the electronic device.  
   
   
       3 . An assembly as set forth in  claim 1  wherein said boiler plate includes a first area being inflexible for overlying the electronic device and a second area being flexible in a thickness less than the thickness of said first area of said boiler plate for allowing said boiler plate to flex in said second area.  
   
   
       4 . An assembly as set forth in  claim 3  including a grease reservoir disposed on said boiler plate to surround the electronic device for receiving grease from a grease layer disposed between said first area and the electronic device as said boiler plate reacts with the electronic device.  
   
   
       5 . An assembly as set forth in  claim 3  wherein said second area surrounds said first area.  
   
   
       6 . An assembly as set forth in  claim 5  including a plurality of heat transfer fins disposed on said first area in said lower portion of said housing.  
   
   
       7 . An assembly as set forth in  claim 3  including a biasing mechanism for connection to the support to facilitate movement of said housing as said boiler plate reacts with the electronic device.  
   
   
       8 . An assembly as set forth in  claim 7  wherein said biasing mechanism includes at least one coil spring for compressing in response to movement of said housing away from the electronic device.  
   
   
       9 . An assembly as set forth in  claim 8  wherein said housing includes flanges disposed on opposite sides of said housing, one of said coil springs reacting with each of said flanges, and a connector for interconnecting each of said coil springs and the support for compressing each of said coil springs in response to movement of said housing away from the electronic device.  
   
   
       10 . An assembly as set forth in  claim 7  including a grease reservoir disposed on said first area to surround the electronic device for receiving grease from a grease layer disposed between said first area and the electronic device as said boiler plate reacts with the electronic device.  
   
   
       11 . An assembly as set forth in  claim 10  including the grease layer disposed on said first area of said boiler plate and in said reservoir for enhancing the thermal interface between said boiler plate and the electronic device.  
   
   
       12 . An assembly as set forth in  claim 10  wherein said upper portion includes a plurality of spaced radiation chambers extending through said housing and a plurality of cooling fins disposed within said radiation chambers.  
   
   
       13 . An assembly as set forth in  claim 12  wherein said housing is generally cubical.  
   
   
       14 . An assembly as set forth in  claim 13  including an air moving device for moving air through said radiation chambers and over said cooling fins.  
   
   
       15 . A thermosiphon cooling assembly for cooling a flat electronic device disposed on a support and comprising; 
 a housing being generally cubical and hermetically sealed and defining a lower portion and an upper portion with said upper portion having a plurality of spaced radiation chambers extending through said housing,    a plurality of cooling fins disposed within said radiation chambers,    an air moving device for moving air through said radiation chambers and over said cooling fins,    a refrigerant disposed in said lower portion of said housing for liquid-to-vapor transformation,    a boiler plate defining a bottom wall of said housing for transferring heat from the electronic device to said refrigerant for liquid-to-vapor transformation and a pressure build up in said housing,    said boiler plate having a first area for overlying the electronic device and a second area surrounding said first area of said boiler plate,    a grease layer disposed between said first area and the electronic device for enhancing the thermal interface between said boiler plate and the electronic device,    a plurality of heat transfer fins disposed on said first area in said lower portion of said housing for enhancing heat transfer to said refrigerant,    said boiler plate being flexible for reacting with the electronic device in response to said pressure build up in said housing by said first area of said boiler plate being inflexible and said second area of said boiler plate being flexible in a thickness less than the thickness of said first area of said boiler plate for allowing said boiler plate to flex in said second area,    a grease reservoir disposed on said first area of said boiler plate to surround the electronic device for receiving grease from said grease layer as said boiler plate reacts with the electronic device,    a biasing mechanism for connection to the support to facilitate movement of said housing as said boiler plate reacts with the electronic device,    said housing including flanges disposed on opposite sides of said housing,    said biasing mechanism including a coil spring reacting with each of said flanges, and    a connector for interconnecting each of said coil springs and the support for compressing each of said coil springs in response to movement of said housing away from the electronic device.    
   
   
       16 . A method of cooling a flat electronic device disposed on a support comprising the steps of; 
 generating heat by the electronic device,    transferring heat from the electronic device to a boiler plate defining an outer wall of a housing being hermetically sealed with the housing defining a lower portion and an upper portion,    transforming a refrigerant disposed in the lower portion of the housing from liquid-to-vapor and increasing a pressure in the housing in response to heat being transferred from the electronic device, and    flexing the boiler plate to react with the electronic device in response to increasing the pressure in the housing.    
   
   
       17 . A method as set forth in  claim 16  further including supporting the housing for movement relative to the electronic device and biasing against such movement of the housing away from the electronic device.