Abstract:
A chassis may include a front section that contains a first electronic circuit board oriented in a first plane, a rear section that contains a second electronic circuit board oriented in a second plane, where the first plane and the second plane are substantially orthogonal, a midplane dividing the front and the rear sections, and a fan tray assembly including a plurality of fans to cool both the first electronic circuit board of the front section and the second electronic circuit board of the rear section.

Description:
BACKGROUND 
       [0001]    Various schemes may be employed for cooling printed circuit boards (PCBs) (e.g., line cards) and other components within a chassis of a device. In instances where a device includes orthogonally oriented PCBs (e.g., horizontal PCBs and vertical PCBs) in a midplane design, there may be at least two fan systems. For example, there may be one fan system to cool the horizontal PCBs and another fan system to cool the vertical PCBs. However, even when employing two fan systems, air flow may not be evenly distributed and may not adequately cool a loaded chassis. 
       SUMMARY 
       [0002]    According to one aspect, a chassis may include a front section that contains a first electronic circuit board oriented in a first plane, a rear section that contains a second electronic circuit board oriented in a second plane, where the first plane and the second plane are substantially orthogonal, a midplane dividing the front and the rear sections, and a fan tray assembly including a plurality of fans to cool both the first electronic circuit board of the front section and the second electronic circuit board of the rear section. 
         [0003]    According to another aspect, a method for cooling a device having a midplane design. The method may include directing a first airflow having a first direction to provide a second airflow having a second direction, the second direction being orthogonal to the first direction, cooling, via the second airflow, a first electronic circuit board of the device, the first electronic circuit board being orthogonal to the midplane, redirecting the second airflow to provide a third airflow having a third direction, the third direction being orthogonal to the second direction, redirecting the third airflow to provide a fourth airflow having a fourth direction, the fourth direction being orthogonal to the third direction, and cooling, via the fourth airflow, a second electronic circuit board of the device. 
         [0004]    According to still another aspect, a device may include a first array of circuit boards oriented in a first direction in a first compartment of a chassis, a second array of circuit boards oriented in a second direction in a second compartment of the chassis, the second direction being different than the first direction, a midplane connecting one or more circuit boards of the first array of the array of circuit boards with one or more circuit boards of the second array of circuit boards, and a fan tray assembly having a plurality of fans disposed on a plane of the first compartment to cool both the first array of circuit boards and the second array of circuit boards. 
         [0005]    According to yet another aspect, a device may include a first plurality of circuit boards oriented in a horizontal direction, a second plurality of circuit boards oriented in a vertical direction, a vertically oriented midplane providing a connection between one or more circuit boards of the first plurality of circuit boards and one or more circuit boards of the second plurality of circuit boards, and a fan system oriented on a plane that is parallel to the second plurality of circuit boards to cool both the first plurality of circuit boards and the second plurality of circuit boards. 
         [0006]    According to still another aspect, a device may include a midplane connecting a first circuit board oriented orthogonal to a second circuit board, a chassis, and a cooling mechanism oriented on a plane corresponding to a side of the chassis, where the cooling mechanism pulls air to cool both the first circuit board and the second circuit board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments described herein and, together with the description, explain aspects of the invention. In the drawings: 
           [0008]      FIG. 1  is a diagram illustrating concepts described herein; 
           [0009]      FIG. 2  is a diagram illustrating an exemplary device that may operate according to the concepts described herein; 
           [0010]      FIG. 3  is a diagram illustrating an exemplary baffle that may correspond to the baffle depicted in  FIG. 2 ; 
           [0011]      FIGS. 4 and 5  are diagrams illustrating exemplary airflow patterns associated with the concepts described herein; and 
           [0012]      FIG. 6  is a flow diagram illustrating a process that may be associated with the concepts described herein. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. 
         [0014]    Spatially relative terms, such as “horizontal,” “vertical,” “front,” and “rear” and the like, may be used herein for ease of description to describe an element or the element&#39;s relationship to another element as illustrated in the figures. Thus, these terms do not necessarily have only one operational meaning and are not intended to be limiting. The same is true for such terms as “beneath,” “below,” “lower,” “above,” “upper,” and the like. 
         [0015]    For example, it will be understood that the spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device illustrated in the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly. 
         [0016]    The term “connect” and variations thereof (e.g., connected or connection) may be direct or indirect. As used herein, the term “and/or” includes any and all combinations of one or more of the associated list items. 
         [0017]      FIG. 1  is a diagram illustrating a device  100  in which concepts described herein may be implemented. As illustrated, device  100  may be, for example, a network device that includes a multi-slot chassis  105  employing a midplane design. Multi-slot chassis  105  may have a generally rectilinear configuration with a front face  110 , a rear face  115 , and a side face  125 . Baffles  120  may be located proximate to rear face  115 . Baffles  120  may include a calibrated perforation density to regulate airflow within device  100 . A matrix of fans  130  may be located proximate to side face  125  that may be used to cool device  100 . 
         [0018]    In accordance with this architecture, a single fan system may cool both horizontally oriented PCBs  135  and vertically oriented PCBs  140  of device  100 . For example, horizontally oriented PCBs  135  may be proximate to front face  110  and vertically oriented PCBs  140  may be proximate to rear face  115 . Additionally, as will be described below, baffles  120  may provide for an even distribution of airflow within device  100 . 
         [0019]    As a result of the foregoing, a single fan system having baffles to regulate air flow may adequately cool a device and PCBs associated therewith. That is, unlike other implementations that may require a fan system (not illustrated) proximate to rear face  115  to cool PCBs  140  and another fan system proximate to side face  125  to cool PCBs  135 , a single fan system  130  may cool PCBs  135  and PCBs  140 . The concepts described herein have been partially described in connection to  FIG. 1 . Accordingly, variations to the above will be described below. 
       Exemplary Device  
       [0020]      FIG. 2  is a diagram illustrating an exemplary device  200  that may operate according to the concepts described herein. As illustrated, device  200  may include, among other components, a chassis  205 , a front face  210 , a rear face  215 , a side face  220 , a side face  225 , PCBs  230 , PCBs  235 , a midplane  240 , baffles  245 , and a fan tray assembly  250 . 
         [0021]    Chassis  205  may be any housing structure to support components of device  200 . In one implementation, chassis  205  may have a rectilinear configuration and may be made of, for example, metal, plastic, etc. Chassis  205  may include slots and/or guides (not illustrated) for receiving and housing a plurality of modules, such as PCBs. As will be described below, in one implementation, the slots and/or guides may receive and house PCBs oriented in a horizontal and vertical fashion in accordance with a midplane design. That is, chassis  205  may be divided into a front compartment  207  and a rear compartment  209  by a transverse midplane, such as midplane  240 . The size and/or dimensions of chassis  205  may be based on the size and number of PCBs to be housed. 
         [0022]    Chassis  205  may include front face  210 , rear face  215 , side face  220 , and side face  225 . Proximate to front face  210 , device  200  may include PCBs  230  oriented in a horizontal fashion, and proximate to rear face  215 , device  200  may include PCBs  235  oriented in a vertical fashion. PCBs  230  and PCBs  235  may each include an array of PCBs, where each PCB is substantially parallel to another PCB within the array. 
         [0023]    Midplane  240  may be any connector for mating one or more PCBs of PCBs  230  with one or more other components, such as one or more PCBs of PCBs  235 . Midplane  240  may be oriented orthogonal to both PCBs  230  and PCBs  235 . Midplane  240  may connect to a power supply (not illustrated). Midplane  240  may permit communication between one or more PCBs  230  and one or more PCBs  235 . 
         [0024]    Baffles  245  may include a structure to regulate airflow within a device. For example, baffles  245  may be metal plates each having a calibrated perforation density to regulate airflow proximate to PCBs  235 . For example, airflow may be regulated based on baffles  245  being positioned and oriented in such a way to create an obstruction to prevent high velocity airflow build-up and minimize re-circulating zones of airflow proximate to PCBs  235 . As illustrated in  FIG. 2 , in one implementation, one baffle of baffles  245  may reside below PCBs  235  and another baffle of baffles  245  may reside above PCBs  235 . Baffles  245  may be orthogonal to PCBs  235 .  FIG. 3  is a diagram illustrating an exemplary baffle  245 . As illustrated, baffle  245  may include multiple holes  305  to regulate airflow. The size, shape, number, and arrangement of holes  305  depicted in  FIG. 3  are exemplary. A perforation density associated with holes  305  may be calibrated. 
         [0025]    For example, baffles  245  may include round holes whose diameters may be varied from 0.140″ to 0.500″ patterned in such a way to maximize the percentage of opening (e.g.,  60 % or more). In certain areas, such as connector area, where no airflow is required, the perforation may be ignored so that the airflow may be concentrated to other areas. 
         [0026]    Fan tray assembly  250  may include a frame having a matrix of fans to cool device  200 . As illustrated, in one implementation, fan tray assembly  250  may be proximate to side face  220 . For example, fan tray assembly  250  may be orthogonal to PCBs  230 . Fans of fan tray assembly  250  may pull air out and/or circulate air to cool device  200 . 
         [0027]    Although  FIG. 2  illustrates an exemplary device  200 , in other implementations fewer, additional, or different components may be utilized. For example, in other implementations, PCBs  230  could be in a rear compartment  209  of device  200  and PCBs  235  could be in a front compartment  207  of device  200 . Additionally, or alternatively, fans of fan tray assembly  250  may push air to cool device  200 . 
         [0028]      FIG. 4  is a diagram illustrating an exemplary airflow pattern associated with the concepts described herein. In  FIG. 4 , device  200  is illustrated from a left side, frontal view. Airflows are illustrated by arrows that correspond to a direction of airflow. An airflow illustrated in  FIG. 4  may be based on, for example, fan tray assembly  250 , air pressure differences, chimney effect, etc. 
         [0029]    As illustrated, airflow  410  may enter device  200  through an opening  405  of front face  210 . For example, opening  405  may be a vented portion of device  200  to permit air to enter device  200 . Airflow  410  may traverse along a bottom face  415  of device  200  toward rear face  215 . Thereafter, airflow  410  may travel upward as airflow  420 . As will be further illustrated and described in connection to  FIG. 5 , airflow  420  may travel through baffles  245  while cooling PCBs  235 . Thereafter, airflow  430  may travel along a plenum existing between a top face  425  of device  200  and PCBs  230 . Finally, airflow  435  may travel toward fan tray assembly  250  of side face  220  to exit device  200  while cooling PCBs  230 . 
         [0030]    Although  FIG. 4  illustrates an exemplary airflow pattern, in other instances, the airflow pattern may include additional and/or different airflows. 
         [0031]      FIG. 5  is a diagram illustrating a partial airflow pattern from a perspective of side  220  that may correspond to the concepts described herein. As previously described, airflow  410  may enter from front face  210  of device  200  toward rear face  215 . Airflow  420  may move upward through baffles  245  to cool PCBs  235 . Based on baffles  245  and their respective perforation density, airflow  420  may be evenly distributed in the rear of device  200 . For example, baffles  245  may regulate airflow  420  to minimize high velocity build-up and/or minimize a re-circulating zone that may have a low velocity epicenter. 
         [0032]    Although  FIG. 5  illustrates an exemplary airflow pattern, in other instances, the airflow pattern may include additional, and/or different airflows. 
         [0033]      FIG. 6  is a flow diagram illustrating a process that may be associated with the concepts described herein. 
         [0034]    Process  600  may begin with an airflow having a first direction being received via an opening of a device (Block  610 ). For example, airflow  410  may be received via opening  405 . Airflow  410  may travel in a first direction, such as a direction from front face  210  to rear face  215 . 
         [0035]    The airflow may be redirected to a second direction that is orthogonal to the first direction (block  620 ). For example, airflow  420  may be directed to a second direction that is orthogonal to the direction of airflow  410 , as illustrated in  FIGS. 4 and 5 . The redirected airflow  420  may cool one or more electrical circuits of device  200 , such as one or more electrical circuits having a first orientation. For example, airflow  420  may cool one or more electrical circuits, such as PCBs  235  that have a vertical orientation. In one implementation, airflow  420  may travel in the second direction via baffles  245 . That is, baffles  245  may redirect airflow  420  upwards. 
         [0036]    The airflow may be redirected to a third direction that is orthogonal to the second direction (block  630 ). For example, airflow  430  may be directed to a third direction that is orthogonal to the direction of airflow  420 . For example, the third direction may correspond to a direction from rear face  215  to front face  210 , as illustrated in  FIG. 4 . 
         [0037]    The airflow may be redirected to a fourth direction that is orthogonal to the third direction (block  640 ). For example, airflow  435  may be directed to a fourth direction that is orthogonal to the direction of airflow  430 , as illustrated in  FIG. 4 . The fourth direction may correspond to a direction from side face  225  to side face  220 . The redirected airflow  435  may cool one or more electrical circuits of device  200 , such as one or more electrical circuits that have a second orientation that is orthogonal to the first orientation. For example, airflow  435  may cool one or more electrical circuits, such as PCBs  230  that have a horizontal orientation. 
         [0038]    In block  650 , the airflow may then exit the device. For example, airflow  435  may exit device  200  via fan tray assembly  250  based on fan tray assembly pulling air from device  200 . For example, fans of fan tray assembly  250  may pull air from device  200  in a direction corresponding to airflow  435 . 
         [0039]    Although  FIG. 6  illustrates an exemplary process, in other instances, process  600  may include fewer, additional, and/or different operations. For example, the airflows described may travel differently if, for example, fan tray assembly  250  pushes air instead of pulling air. Additionally, or alternatively, the description of directions in relation to faces of device  200  may be different. For example, if PCBs  230  were in a rear compartment  209  of chassis  205  and PCBs  235  were in a front compartment  207  of chassis  205 , airflow  410  may travel in a direction from rear face  215  to front face  210 , and the remaining airflows may travel in a manner corresponding to that described above. 
       CONCLUSION 
       [0040]    The foregoing description of implementations provides an illustration, but is not intended to be exhaustive or to limit the implementations to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the teachings. 
         [0041]    In addition, while a series of blocks has been described with regard to the process illustrated in  FIG. 6 , the order of the blocks may be modified in other implementations. Further, non-dependent blocks may be performed in parallel. Further, it may be possible to omit blocks within the process of  FIG. 6 . 
         [0042]    Even though particular combination of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the invention. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. 
         [0043]    No element, block, or instruction used in the present application should be construed as critical or essential to the implementations described herein unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.