Abstract:
An electronic system enclosure including cooling units to regulate temperature of electrical components therein. In one embodiment, the electronic system enclosure includes field replaceable units which facilitate concurrent maintenance. In this embodiment, air pressure within the electronic system enclosure is maintained while a field replaceable unit is removed. Also in this embodiment, cooling of the remaining electrical components of the electronic system enclosure is continued during removal of a field replaceable unit.

Description:
BACKGROUND 
       [0001]    The present invention relates to an electronic system enclosure, and, more specifically, relates to an enclosure having a first removable unit and a second removable unit that may include power supplies and cooling fans. 
         [0002]    Electronic system enclosures may include cooling systems to regulate the temperature of their electrical components. One type of cooling system is a forced air system that relies on a plurality of air movers to blow air over the electrical components in order to cool the components. Replacement of a failed cooling unit or performing maintenance on the electrical components involves the extraction of the power supply from the electronic system enclosure. 
       SUMMARY 
       [0003]    An example embodiment of the present invention is an electronic system enclosure which includes a plurality of field replaceable enclosures. The field replaceable enclosures include side vents. Also included in the electronic system enclosure is a plurality of biased flaps attached to the electronic system enclosure below the field replaceable enclosures. When one of the field replaceable enclosures is removed from the electronic system enclosure, the flaps are actuated into position and create an airflow path to a side vent of another field replaceable enclosure remaining in the electronic system enclosure. The embodiment may include a mid-plate located above the field replaceable enclosures. The mid-plate defines a top chamber in the electronic system enclosure. The mid-plate includes a plurality of openings configured to facilitate airflow from the top chamber to the field replaceable enclosures. 
         [0004]    The example embodiment may further include two flaps. The first flap and the second flap are actuated in tandem when one of the field replaceable enclosures is removed from the electronic system enclosure. In this example configuration the first flap is configured to substantially prevent airflow from directly entering the side vent of the field replaceable enclosure remaining in the electronic system enclosure. The second flap is configured to substantially prevent positively pressurized airflow from circulating back into the second field replaceable enclosure remaining in the electronic system enclosure through the side vent. 
         [0005]    Further, the field replaceable enclosures of the example embodiment may include cooling fans that are configured to provide airflow throughout the electronic system enclosure. The field replaceable enclosures may also include power supplies. 
         [0006]    Another example of the embodiment of the present invention is an electronic system enclosure which includes a plurality of field replaceable enclosures which include side vents. The example electronic system enclosure also includes a plurality of flaps attached to the electronic system enclosure above the field replaceable enclosures. The flaps of the example electronic system enclosure are actuated when one of the field replaceable enclosures is removed from the electronic system enclosure. The actuated flaps create an airflow path to a side vent of another field replaceable enclosure remaining in the electronic system enclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0008]      FIG. 1  shows an example electronic system enclosure including a plurality of field replaceable enclosures contemplated by the invention. 
           [0009]      FIG. 2  shows an example electronic system enclosure with one of the field replaceable enclosures removed. 
           [0010]      FIG. 3  shows a sectional view of electronic system enclosure with one of the field replaceable enclosures removed. 
           [0011]      FIG. 4  shows a cross-sectional side view of an example electronic system enclosure with the first flap and second flap actuated to an upright position. 
           [0012]      FIG. 5  shows a cross-sectional side view of a field replaceable enclosure partially inserted into the example electronic system enclosure with the second flap actuated to an upright position. 
           [0013]      FIG. 6  shows a particular embodiment of the invention wherein the cooling fans in the field replaceable enclosures embodied as a counter-rotating fan housing two independent rotors. 
           [0014]      FIG. 7  shows an alternative example of the electronic system enclosure where the flaps are positioned above the field replaceable enclosures hinged from the top of the electronic system enclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The present invention is described with reference to embodiments of the invention. Throughout the description of the invention reference is made to  FIGS. 1-7 . 
         [0016]    Aspects of the invention relate to equipment placed in a server rack. For example, once the electronic enclosure is placed in the server rack it can typically be accessed from either the front or the back to perform service; all other internal components are generally inaccessible. There is usually little room in the front and the back compared to the amount of components in the electronic enclosure. Cool airflow, air pressure and power should be maintained throughout the electronic enclosure when the enclosure is inserted in the rack and when a field replaceable unit is extracted for maintenance or repair. 
         [0017]    The challenge is to use a minimum number of fans necessary for cooling. It is important to keep the use of the cooling fans to a minimum because cooling fans tend to be noisy, expensive and failure prone. Also, it is beneficial to have the fans in a location such that if some of the fans break, they can be replaced while maintaining functionality of and power to the enclosed equipment. For example, positioning the cooling fans in a field replaceable unit, as opposed to behind disk drives, can have an added benefit of not requiring the removal of the disk drives to access the cooling fans. Also, hard drives may be serviced in place reducing potential errors to the hard drives caused by removal. 
         [0018]      FIG. 1  illustrates an example electronic system enclosure  102  contemplated by the invention. In one embodiment, the electronic system enclosure  102  is a rack-mount device designed to be rack-mounted in a standardized frame or enclosure. The electronic system enclosure  102  may be constructed from sheet metal, plastic and/or other suitable materials known by those skilled in the art. The electronic system enclosure  102  includes a plurality of field replaceable enclosures  104  and  106 . 
         [0019]    As discussed in more detail below, the field replaceable enclosures  104  and  106  may be removed and reinserted into the electronic system enclosure  102  by actuating a handle which disengages the field replaceable enclosure permitting them to be slid in and out. Removal of a field replaceable enclosure can facilitate access and service of components within the field replaceable enclosure, as well as the electronic system enclosure  102 . 
         [0020]    In a particular embodiment, the electronic system enclosure  102  includes an array of storage units  108 . The storage units  108  may, for example, include hard drives, tape drives, or other devices for storing computer data. The electronic system enclosure  102  may further include assembly port expander cards embedded with storage unit control electronics  110  located between the storage units  108 . As discussed below, the field replaceable enclosures  104  and  106  may include power supplies configured to supply power in a redundant manner to the storage units  108  and other devices in the electronic system enclosure  102 . 
         [0021]    Turning now to  FIG. 2 , the electronic system enclosure  102  is shown with one of the field replaceable enclosures  104  removed. As shown, each field replaceable enclosure  104  may include one or more cooling fans  206 . The cooling fans  206  are configured to provide airflow throughout the electronic system enclosure  102 . For example, the cooling fans  206  can create a top to bottom airflow, drawing air down from above the field replaceable enclosure  104  and circulating the air within the electronic system enclosure  102 . In a particular embodiment, the cooling fans  206  may be replaced or repaired by removing a field replaceable enclosure  104  and extracting the cooling fans  206 . As detailed further below, the fans may be of the counter rotating variety  206 . 
         [0022]    Each field replaceable enclosure  104  and  106  may include a top vent  202  and side vents  204 . The top vent  202  is configured to facilitate airflow from a top chamber into the field replaceable enclosures. In one embodiment, the top vent  202  may include a series of openings to facilitate circulation of air throughout the electronic system enclosure. 
         [0023]    The side vents  204  of the field replaceable enclosure  104  allow airflow due to the cooling fans  206  to enter the field replaceable enclosure  104 . Each field replaceable enclosure has at least one side vent  204 . In one embodiment, each field replaceable enclosure includes a left side vent  204  and a right side vent  204 . In one embodiment, the side vents  204  may include a series of openings to facilitate circulation of air throughout the electronic system enclosure. 
         [0024]    Each field replaceable enclosure  104  may include one or more power supplies  210 . The power supplies  210  are electrically coupled in parallel circuit such that power is maintained without interruption to other devices in the electronic system enclosure when one of the field replaceable enclosures is removed from the electronic system enclosure  102 . 
         [0025]      FIG. 3  shows a sectional view of the electronic system enclosure  102  with one field replaceable enclosure removed. The electronic system enclosure  102  includes a mid-plate  310  above the field replaceable enclosures  104  and  106 . The mid-plate  310 , along with a back wall  306 , define an upper chamber  320  within the electronic system enclosure  102 . The mid-plate  310  further comprises a plurality of openings which are configured to facilitate airflow from the top chamber  320  to the field replaceable enclosures  104  and  106 . As mentioned above, the top chamber  320  may contain, for example, disk drives  108  and card assembly port expander cards embedded with storage unit control electronics  110  located between the storage units  108 . 
         [0026]    The cooling fans  206  of the field replaceable enclosure  104  create top to bottom airflow. Air is drawn down from above the field replaceable enclosures  104 , through the openings of the mid-plate  310 , and is then circulated through rest of the electronic system enclosure  102 . 
         [0027]    The system enclosure  102  may further include a back chamber  318  behind the field replaceable enclosures  104  and  106 . In one embodiment, the back chamber  318  includes a plurality of PCI slots  308 . The PCI slots may be used for connecting PCI circuit boards in the electronic system enclosure  102 . 
         [0028]    Airflow throughout the electronic system enclosure  102  is further facilitated through the PCI slots  308  which are located downstream from the airflow path exiting the field replaceable enclosures  104 . Front to back airflow may be maintained throughout the field replaceable enclosure  102 . Air is pulled into the field replaceable enclosure  104  and exits the rear of the electronic system enclosure  102  in parallel. 
         [0029]    As shown, the electronic system enclosure  102  includes a plurality of spring loaded flaps  312  and  314 , located beneath the field replaceable enclosures  104  and  106  when the field replaceable enclosures  104  are installed. In one embodiment, the field replaceable enclosures  104  may include a first flap  312  and a second flap  314 . The electronic system enclosure  102  further includes an airflow wall  316  behind the field replaceable enclosures  104  and  106 . The airflow wall includes a series of openings allowing air to pass. 
         [0030]    On removal of a field replaceable enclosure  104 , flaps  312  and  314  are actuated into an upright position. When flaps  312  and  314  are in the upright position, an air channel is formed with suction through the side vent of the remaining field replaceable enclosure. This suction allows the remaining field replaceable enclosure  106  to cool the entire electronic system enclosure  102  without disrupting operation of devices in the electronic system enclosure  102 . 
         [0031]    Actuated flaps  312  and  314  may form a uniform pressure region or plenum  322  in front of PCI cards  306 . Cooling of the electronic system enclosure  102  may be maintained even with the field replaceable enclosure  104  and the corresponding power supply  210  removed. Thus, the flaps  312  and  314  beneficially maintain cool airflow and positive pressure throughout the field replaceable enclosure  102  even when one of the field replaceable enclosures is removed. 
         [0032]    In one embodiment of the invention, the electronic system enclosure  102  includes a first flap  312  and second flap  314  below each field replaceable enclosure. The first flap  312  and second flap  314  are actuated in tandem when a field replaceable enclosure is removed from the electronic system enclosure  102 . 
         [0033]    The first flap  312  is configured to substantially prevent airflow from directly entering the side vent of the remaining field replaceable enclosure  106  without first entering the top chamber  320 . The second flap  314  is configured to substantially prevent positively pressurized airflow of the plenum  322  from recirculating back into the second field replaceable  106  enclosure through the side vent  204  of the remaining field replaceable enclosure  106 . 
         [0034]      FIG. 4  shows a cross-sectional side view of the electronic system enclosure  102  with the first flap  312  and second flap  314  actuated to an upright position. As discussed above, the first flap  312  is configured to substantially prevent airflow  402  from directly entering the side vent of the remaining field replaceable enclosure  106  without first entering the top chamber  320 . Furthermore, the second flap  314  is configured to substantially prevent positively pressurized airflow  404  within the plenum  322  from circulating back into the second field replaceable enclosure through the side vent  204  of the remaining field replaceable enclosure  106 . It is noted that the parallelogram shape of the side vent  204  is completely enclosed by the channel created between the first flap  312  and second flap  314  actuated in the upright position. 
         [0035]      FIG. 5  shows a cross-sectional side view of a field replaceable enclosure  104  partially inserted into the electronic system enclosure  102 . In this position, it can be seen that flaps  312  and  314  can work independently of each other. The second flap  314  is actuated into position by the removal of the first field replaceable enclosure  104 , which substantially prevents airflow from the plenum  322  from entering the side vent  204  of the remaining second field replaceable enclosure  106 . Thus, the plenum  322 , partially defined by the second flap  314 , stays pressurized such that there is no backflow into the remaining second field replaceable enclosure  106  through its side vent  204 . 
         [0036]    Flaps  312  and  314  not only block backflow. Actuated flaps  312  and  314  also redirect airflow to continue cooling components of the electronic system enclosure  102 . The actuated flaps  312  and  314  create a negatively pressurized region which draws air from components upstream of the airflow path (i.e., in the top chamber  320 ) entering the remaining second field replaceable enclosure  106 . 
         [0037]      FIG. 6  shows a particular embodiment of the invention wherein the cooling fans  206  in the field replaceable enclosures are embodied as a counter-rotating fan housing two independent rotors. In this embodiment, a cooling fan  206  is comprised of a first rotor in its own housing  602  and a second rotor in its own housing  604 . It is further contemplated that the first rotor  602  and the second rotor are independent of each other. For example, each rotor  602  and  604  includes a separate power supply and control mechanism to reduce the chances that both rotor  602  and  604  will fail at the same time. In this configuration, if either the first rotor  602  or the second rotor  604  fails, circulation of cool air is maintained in the electronic system enclosure  102  without backflow. This can be accomplished because one of the cooling rotor remains operable, thus preventing air recirculation back to the field replaceable enclosure  104 . 
         [0038]    The cooling rotor may be positioned such that the air exiting the first rotor  602  enters the second rotor  604 . Also, the first rotor  602  is configured to rotate in the opposite direction of the second rotor  604 , thereby reducing turbulence and amplifying airflow. Further, space is saved by the ability of placing the rotor closely next to each other. 
         [0039]    In  FIG. 7 , an alternative embodiment of the electronic system enclosure  702  is shown. In this embodiment, the flaps  704  and  706  are positioned above the field replaceable enclosures  708  and can be actuated, for example, by gravity. As discussed above, when one of the field replaceable enclosures  708  is removed from the electronic system enclosure  702  the flaps  704  and  706  create an airflow path to a side vent of another field replaceable enclosure  708  remaining in the electronic system enclosure  702 . 
         [0040]    While the preferred embodiments to the invention have been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. For example, the electronic system enclosure described above may be used to house and power many types of electronic devices, not only I/O and disk drive devices. Thus, the claims should be construed to maintain the proper protection for the invention first described.