Patent Publication Number: US-2012044633-A1

Title: Extruded server case

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a Division of application Serial No. 13/182,866 filed on Jul. 14, 2011, which claims the benefit of U.S. Provisional Application 61/378,046 filed Aug. 30, 2010, which applications are incorporated by reference herein in their entirety. 
    
    
     FIELD 
     This disclosure relates to a liquid submersion cooled computer, for example a server computer or a personal computer. 
     BACKGROUND 
     Examples of liquid submersion cooled computers are disclosed in U.S. Pat. No. 7,403,392 and in U.S. Patent Application Publication No. 2009/0260777. 
     SUMMARY 
     A liquid submersion cooled computer is described that includes a seamless, extruded main body used to form a liquid-tight case holding a cooling liquid that submerges components of the computer. By forming the main body as a seamless extrusion, the number of possible leakage paths from the resulting liquid-tight case is reduced. No seams are provided on the main body, and there are no openings through the walls of the main body, so liquid cannot leakage through the main body. Any leakage paths are limited to joints between the main body and end walls which are sealingly attached to the main body to form the liquid-tight case. 
     The liquid submersion cooled computer can be any type of computer. For example, the computer can be a server computer. A liquid submerged server computer is described in U.S. Patent Application Publication No. 2009/0260777 which is incorporated herein by reference in its entirety. In another example, the computer can be a personal computer. A liquid submerged personal computer is described in U.S. Pat. No. 7,403,392 which is incorporated herein by reference in its entirety. 
     The extruded main body can be formed from any extrudable material. For example, the main body can be extruded from a metal including, but not limited to, aluminum, or from a polymeric material such as a thermosetting plastic. 
     In one embodiment, a liquid submersion cooled server computer includes a liquid-tight case having a main body that includes a plurality of walls defining an interior space. The main body also includes a first end and a second end. The main body is seamless and formed from an extruded material. In addition, the walls of the main body are devoid of openings therethrough so that the interior space is not in communication with an exterior of the main body through the plurality of walls. The case further includes a first end wall closing the first end and a second end wall closing the second end. A server logic board is disposed in the interior space of the main body, and heat generating computer components, including a processor, are disposed on the server logic board. A dielectric cooling liquid is disposed within the interior space and submerges the plurality of heat generating computer components, including the processor, disposed on the server logic board. In addition, a liquid inlet for dielectric cooling liquid and a liquid outlet for dielectric cooling liquid are provided on the first end wall or on the second end wall. 
     The term “seamless” is intended to mean that the walls of the main body are not initially separate from each other and then joined together. The joining of separate walls to form the main body would create seams between the walls which increases the chances of a failure or defect in the joint between two of the walls, thereby creating a leakage path for the cooling liquid from the interior of the case. In contrast, by forming the main body as a seamless extrusion, the walls of the main body are integrally formed, and there are no seams between the walls. As a result, there are no leakage paths through the main body. 
     In another embodiment, a server computer case comprises a plurality of walls defining an interior space, the walls having a first end and a second end. The walls are seamless and are formed from an extruded material, and the walls are devoid of openings therethrough so that the interior space is not in communication with ambient air through the plurality of walls. Ridges are formed on outer surfaces of the plurality of walls at the first end and the second end, and the ridges include threaded holes at the first end and the second end for receiving threaded fasteners that are used to secure end walls to the case to define a liquid-tight case. 
    
    
     
       DRAWINGS 
         FIG. 1  is a perspective view of a liquid submersion cooled server computer with an extruded case as described herein. 
         FIG. 2  is a perspective view from the rear of the liquid submersion cooled server computer of  FIG. 1 . 
         FIG. 3  is a perspective view similar to  FIG. 1  with a side wall and top wall of the extruded main body made transparent to show the interior of the case. 
         FIG. 4  shows the server computer with a tray assembly partially removed through the rear of the extruded case. 
         FIG. 5  shows the tray assembly. 
         FIG. 6  is an end view of the extruded main body showing edges of the server logic board received in extruded slots. 
         FIG. 7  is an end view of another embodiment showing edges of the tray assembly received in extruded slots. 
         FIG. 8  is a perspective view of an embodiment of the extruded main body that includes heat exchange fins on the interior and exterior of the main body. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 and 2  illustrate a liquid submersion cooled computer  10  in the form of a blade server computer. The concepts described herein can also be applied to a liquid submersion cooled personal computer. 
     The computer  10  includes a sealed, liquid-tight case  12  that contains therein a cooling liquid that submerges heat generating components of the computer so that the submerged components are in direct contact with the cooling liquid inside the case  12 . The cooling liquid can be, but is not limited to, a dielectric liquid. Dielectric liquids that can be used include, but are not limited to: 
     Engineered fluids like 3M™ Novec™ 
     Mineral oil 
     Silicone oil 
     Natural ester-based oils, including soybean-based oils 
     Synthetic ester-based oils 
     The liquid can be single phase or two-phase. It is preferred that the liquid have a high enough thermal transfer capability to handle the amount of heat being generated by the submerged components so that the liquid does not change state. Enough of the liquid is present in the case  12  in order to submerge the heat generating components of the computer that one wishes to submerge. So in some instances the liquid may fill substantially the entire case  12 , while in other instances the liquid may only partially fill the case  12 . 
     The heat generating components in the case  12  that can be submerged are those that are electronically and/or thermally active. Examples of heat generating components that are electronically and/or thermally active are processors, power supply units, memory and storage devices, management hardware, and other components. 
     With reference to  FIGS. 1 ,  2  and  6 , the case  12  includes a main body  14  that includes a plurality of walls  20   a ,  20   b ,  20   c ,  20   d  defining an interior space  22 , a first end wall  16  closing a first open end of the main body and a second end wall  18  closing a second open end of the main body. When the first end wall  16  and the second end wall  18  are attached to the main body  14 , a sealed, liquid-tight space is created for containing the server electronics and the cooling liquid. As will be described further below, the second end wall  18  includes a valved liquid inlet and a valved liquid outlet to allow cooling liquid to enter and exit the interior space. Therefore, a sealed, liquid-tight space is intended to mean that there is no unintentional leakage or other unintentional movement of cooling liquid from the case  12 , despite there being the ability for cooling liquid to intentionally flow into and out of the case  12  through the inlet and the outlet. 
     The main body  14  is formed from an extruded material so that the walls  20   a ,  20   b ,  20   c ,  20   d  are integrally formed and the main body  14  is seamless. The extruded main body can be formed from any extrudable material that one finds suitable for use on a server. For example, the main body  14  can be extruded from a metal including, but not limited to, aluminum, or from a polymeric material such as a thermosetting plastic. Extruding the main body  14  from aluminum helps to reduce the weight of the resulting case  12 , and using aluminum (or other metal) for the main body helps to dissipate heat from the cooling liquid inside the case via conduction. Further, extruding the main body  14  eliminates seams between the walls, so that the main body is seamless. This eliminates any leakage paths through the main body. The process of extruding metals and polymeric materials is well known to those of ordinary skill in the art. 
     Unlike conventional server and other computer housings which have holes or other openings in the housing to allow air to flow between the inside and outside of the housing, the main body  14  is devoid of any openings in the walls  20   a - d  so that the interior space  22  is not in communication with the exterior of the main body or ambient air through the walls. 
     As shown in  FIGS. 1-3 , the extruded main body  14  includes a plurality of raised ridges  24  formed on exterior surfaces of the plurality of walls  20   a - d . The ridges  24  extend continuously from the first end of the main body to the second end and form means by which the end walls  16 ,  18  can be secured to the main body. In particular, the ridges  24  include threaded holes  26  at the first end and the second end (the threaded holes  26  at the first end of the main body are visible in  FIG. 7 ) that receive threaded fasteners  28 , such as screws, to secure the end walls  16 ,  18  to the main body. The threaded holes  26  do not extend through the entire length of the ridges  24 . Instead, the threaded holes  26  need only extend a sufficient distance into each ridge  24  to receive the threaded fasteners. 
     In the embodiment of the main body illustrated in  FIGS. 1-4 , the interior surfaces of the walls  20   a - d  are generally smooth and flat. However, as shown in the embodiments in  FIGS. 6 and 7 , the two walls  20   b ,  20   d  disposed opposite each other can be formed with extruded slots  30   a ,  30   b  on their interior surfaces. The slots  30   a ,  30   b  extend continuously from the first end of the main body to the second end. As will be described further below, the slots  30   a ,  30   b  slidably receive opposite edges of a logic server board ( FIG. 6 ) or opposite edges of a tray on which the logic server board is mounted ( FIG. 7 ) to facilitate insertion and removal of the server board. 
     In addition to extruded slots, or separately from slots, the main body  14  can be extruded with a plurality of integral heat exchange fins  32  illustrated in  FIG. 8 . The heat exchange fins  32  can be formed on one or more interior surfaces of the walls  20   a - d , and/or formed on one or more exterior surfaces of the walls  20   a - d . The provision of heat exchange fins  32  would increase the conductive heat transfer from the cooling liquid inside the case to the ambient air. 
     Turning to  FIGS. 1-5 , the end walls  16 ,  18  are secured to the first and second ends of the main body, and are sealed therewith, to close the interior space  22  and define an interior volume for holding the cooling liquid. The end walls  16 ,  18  are preferably formed of the same material used to form the extruded main body  14 , but could be formed of different material. The means for forming the seal between the end walls  16 ,  18  and the main body are the same for each end wall  16 ,  18  and will be described with respect to the end wall  18 . 
     With reference to  FIGS. 4 and 5 , the end wall  18  is generally rectangular in shape. A continuous raised lip  40  is formed on the inside surface of the end wall  18  and is sized and shaped to fit closely with the interior surfaces of the walls  20   a - d  at the second end. A sealing gasket  42  is disposed around the lip  40 . The gasket  42  seals with the interior surfaces of the walls  20   a - d , and a perimeter edge  44  of the end wall around the lip  40  is engaged with the end faces of the walls  20   a - d . This creates a liquid-tight seal to prevent leakage of cooling liquid from the interior. 
     The end wall  18  is also provided with a liquid inlet  46  to allow cooling liquid to enter the case  14  and a liquid outlet  48  to allow cooling liquid to exit the case. The inlet  46  and the outlet  48  are provided with quick connect/disconnect valves that are designed to automatically open/close upon connection/disconnection with mating fluid conduits. Although the inlet  46  and the outlet  48  are described as being on the end wall  18 , the locations of the inlet and the outlet could vary. For example, in certain embodiments, the inlet and outlet could be on the end wall  16 . In addition, the inlet could be on one end wall and the outlet could be on the other end wall. 
     The inlet and the outlet are connected to a thermal dissipation or recovery device (not shown). The thermal dissipation or recovery device can be any device that is suitable for dissipating heat or allowing recovery of the heat from the cooling liquid from inside the case. For example, the device can be a simple heat exchanger, such as a radiator, for dissipating heat. Air or liquid could be used as the heat exchanging medium. In addition, the heat exchanger could be disposed underground to allow the relatively cool ground to cool the liquid. The external heat exchanger can take on a number of different configurations, as long as it is able to cool the liquid down to an acceptable temperature prior to being fed back into the case. Examples of thermal dissipation devices include, but are not limited to, a cooling stack, evaporation, and an in-ground loop. A pump is used to pump the cooling liquid from the case, to the thermal dissipation or recovery device, and back into the case. Further information on thermal dissipation or recovery devices can be found in U.S. Patent Application Publication No. 2009/0260777. 
     With continued reference to  FIGS. 4 and 5 , the end wall  18  further includes pass-through input/output (I/O)  50  and power  52  connectors. The I/O connector  50  engages with an input/output bus to pass external component I/O, storage I/O into and out of the case  14  to and from the server logic board and its components. The power connector  52  passes electrical power, such as AC power, into the case from an external power source. The connectors  50 ,  52  can be any type of connectors suitable for passing I/O and power into and from the case. Each of the connectors  50 ,  52  is sealingly fixed to the end wall  18  in a manner to prevent fluid leakage past the connectors. 
     The perimeter edge of the end wall  18  is provided with a plurality of spaced ears  54  that correspond in location to the ridges  24 . The ears  54  abut against the ridges  24  and are provided with holes  56  through which the threaded fasteners  28  extend to secure the end wall  18  to the main body  14 . 
     With reference to  FIGS. 1 and 3 , the end wall  16  is constructed somewhat similarly to the end wall  18  so as to seal with the first end of the main body in the same manner as the end wall  18 . The end wall  16  includes a plurality of user interface devices such as an on/off button  60  and status indicators  62 . Each interface device is sealingly fixed to the end wall  16  in a manner to prevent fluid leakage past the interface device. 
     The perimeter edge of the end wall  16  is provided with a plurality of spaced ears  64  that correspond in location to the ridges  24 . The ears  64  abut against the ridges  24  and are provided with holes through which the threaded fasteners  28  extend to secure the end wall  16  to the main body  14 . 
     A plurality of electronically and/or thermally active computer components that together form a complete computing system, for example forming a server computing system, are disposed within the case  12 . Examples of computer components that are electronically and/or thermally active include, but are not limited to, processors, one or more power supply units, memory and storage devices, management hardware, and other components. 
     For a server computer, the computer components are mounted on a server logic board  70 . In the embodiment illustrated in  FIGS. 1-5 , the logic board  70  is in turn mounted on a metal tray  72  that is slidably disposed within the interior space of the main body  14  to allow the tray  72  and the logic board  70  mounted thereon to be removed from and inserted into the main body as shown in  FIG. 4 . As shown in  FIG. 5 , the tray  72  includes a side wall  74  to which the logic board  70  is attached, and a pair of upturned flanges  76 ,  78  extending the length of the tray  72 . One end of the tray  72  is fixed to the end wall  18  and is designed to be removed from second end of the main body  14  when the end wall  18  is removed. Alternatively, the tray can be fixed to the end wall  16  so as to removable from the main body through the first end when the end wall  16  is removed. 
     Two curved guides  80 ,  82  are formed on the flanges  76 ,  78  at the end opposite the end wall  18 . The guides  80 ,  82  match the curvature between the walls  20   a ,  20   c  and the walls  20   b ,  20   d  to help stabilize the tray within the case and to guide the tray as it is removed from and installed into the case  12 . 
     With reference to  FIG. 6 , instead of using a tray, opposite edges of the logic board  70  can be slidably disposed within the extruded slots  30   a ,  30   b .  FIG. 7  illustrates an embodiment where opposite edges of a tray  90 , to which the logic board  70  is attached, are slidably disposed within the extruded slots  30   a ,  30   b.    
     Once the computing system is disposed within the case  12  and the end walls  16 ,  18  are secured to the main body  14 , the case is filled with the cooling liquid. The cooling liquid is introduced through the inlet  46 . The interior space of the case is filled with the cooling liquid to a level to submerge the desired computing components in the cooling liquid. The cooling liquid is also filled to the level of the outlet  48 . If only certain of the components need to be submerged, and those components are located lower on the logic board, then the liquid need only fill a portion of the interior space. In that instance, the location of the outlet  48  would need to be changed so as to be lower on the end wall  18  at or below the level of the liquid, or the outlet location  48  can remain the same but a fluid connection established between the outlet and the liquid. 
     The concepts described may be embodied in other forms without departing from the spirit or novel characteristics thereof. The examples disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.