Abstract:
A cooling apparatus of an array of fan cradles holding fans where a movable baffle assembly directs airflow and blocks removal of more than one fan at a time. A plurality of fans held in a fan cradle assembly in which the fan cradle for a fan to be replaced mechanically moves and is engaged with the movable baffle assembly to prevent removal of the other fans. A method is provided by which an operator may remove and replace an existing fan in an array of fans.

Description:
TECHNICAL FIELD 
     This disclosure relates generally to cooling systems for electronics and more particularly to a cooling system that redirects airflow when removing a fan and provides for removal of only one fan in an array of fans at a time. 
     BACKGROUND 
     One aspect of thermally managing and maintaining electronic systems involves properly cooling equipment to provide for reliability and proper performance. Properly cooling equipment typically requires generating airflow to remove heat generated by the equipment and maintain the temperature of various components within a suitable operating range. Air moving in parallel airflow paths impelled by air moving devices such as fans cools the components. 
     An individual fan may not supply the cooling needs of a system as a whole. Thus, multiple fans operate simultaneously to achieve the airflow necessary to cool the system. Though overall cooling system fan configurations vary, each individual fan in an array of fans contributes to the overall airflow. In addition, systems that use forced air cooling frequently use multiple fans so that if one fan fails another can continue to provide cooling for the system. 
     SUMMARY 
     In an embodiment, this disclosure relates to a cooling apparatus to direct and redirect airflow when removing and replacing a fan while also providing for removal of only one fan at a time through use of a movable baffle assembly. The cooling apparatus may include at least two fan cradles, at least two fans, and the movable baffle assembly. The movable baffle assembly may direct and redirect airflow and also may block removal of at least one fan. 
     In an embodiment, the cooling apparatus may be positioned in a home position directing airflow and blocking removal of fans or may be positioned in a swap position redirecting airflow and blocking removal of a fan. In another embodiment, this disclosure relates to a method for an operator to remove and replace an existing fan in an array of fans by manipulating a baffle, substituting fans, and manipulating a fan cradle where the baffle assembly blocks removal of fans still operating. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  diagrammatically depicts an embodiment of a cooling apparatus in a home position. 
         FIG. 2  diagrammatically depicts an embodiment of a cooling apparatus in a swap position. 
         FIG. 3  is a flowchart according to an embodiment of a method to remove and replace an existing fan in an array of fans. 
     
    
    
     DETAILED DESCRIPTION 
     Information technology systems such as servers, storage systems, and switches generate significant amounts of heat and often require numerous fans to cool the components. In many such settings, the impracticalities of shutting down a system to remove and replace fans call for the maximization of system uptime by swapping fans without shutting down the system, or hot-swapping. To continue cooling of the system as a whole, other fans must stay in place when removing and replacing a fan. When removing and replacing a fan, the system may cool better by allocating airflow from a remaining fan or fans to the area previously cooled by the fan being removed and replaced. 
     An aspect of the disclosure includes limiting the number of nonoperational fans by removing only one fan at a time during replacement. Another aspect of the disclosure includes allocating airflow from operational fans to an area previously cooled by a nonoperational fan. This may deter overheating or cause less stress on components in the area the nonoperational fan no longer cools. This may help components that have less ability to throttle and protect themselves from overheating. Embodiments of the described disclosure include an apparatus that can direct and redirect airflow when removing and replacing a fan while also providing for removal of only one fan at a time. 
       FIG. 1  diagrammatically depicts an embodiment of a cooling apparatus in a home position. The home position may represent a standard operating state with working fans. A movable baffle assembly  100  may include an airflow diverter plate  101  coupled with a fan stop plate  102 . The fan stop plate  102  may block removal of a first fan  310  and a second fan  320 . The blocking may mechanically occur by the fan stop plate  102  without operator action. The airflow diverter plate  101  may segregate airflow into paths which may be parallel. The airflow diverter plate  101  may direct a first airflow  410  from the first fan  310  and a second airflow  420  from the second fan  320 . A fan cradle  210  may hold the first fan  310  and a fan cradle  220  may hold the second fan  320 . In other embodiments, more fan cradles may be provided, for example, three fan cradles. In a three fan cradle embodiment, a movable baffle assembly could allow for removal of a single fan while blocking the removal of the two remaining fans. In further embodiments, a two fan cradle or three fan cradle may be provided in which each fan cradle carried a twin fan combination in which the twin fan combination would be the replaceable component. 
     A cradle biasing mechanism  213  may orient the fan cradle  210 . The cradle biasing mechanism  213  may mechanically favor orienting the fan cradle  210  in a swap position as in  FIG. 2 . However, in the home position depicted in  FIG. 1 , the fan stop plate  102  may obstruct the cradle biasing mechanism  213  from orienting the fan cradle  210 . A baffle biasing mechanism  103  may orient the movable baffle assembly  100 . The baffle biasing mechanism  103  may mechanically favor orienting the movable baffle assembly  100  in the home position depicted in  FIG. 1 . Embodiments according to the disclosure may include spring-loading the cradle biasing mechanism  213  or the baffle biasing mechanism  103 . In  FIG. 1  or  FIG. 2 , the spring-loaded feature may be considered to be within the cradle biasing mechanism  213  or the baffle biasing mechanism  103 . 
       FIG. 2  diagrammatically depicts an embodiment of a cooling apparatus in a swap position. The swap position represents a machine operating state where an operator, such as service personnel, may replace a fan. The airflow diverter plate  101  may allocate airflow into paths. The fan stop plate  102  may permit removal of the first fan  310  and block removal of the second fan  320 . The blocking of the second fan  320  may mechanically occur by the fan stop plate  102  without operator action. Circle  600  identifies that the fan stop plate  102  may block the second fan  320  from removal. With no mechanical or other restriction, circle  600  also identifies that the first fan  310  may be removed as the fan stop plate  102  may have no effect on either the first fan  310  or the fan cradle  210 . Airflow from the first fan  310  may not exist. The airflow diverter plate  101  may direct airflow  421  and airflow  422  from the second fan  320 . Airflow  421  may cool a path that may resemble airflow  420  in  FIG. 1 . Airflow  422  may cool a path that may resemble airflow  410  in  FIG. 1 . The second fan  320  may compensate for the increased cooling demands by ramping up in revolutions per minute. 
     The cradle biasing mechanism  213  may orient the fan cradle  210  in its mechanically favored swap position. According to some embodiments, the cradle biasing mechanism  213  may tilt or rotate a fan cradle from a first position to a second position such as the elevated and tilted position diagrammatically illustrated in  FIG. 2 . In other aspects, other changes in the mechanical position of the fan cradle may be used to produce the appropriate swap position for a fan while blocking removal of another fan or fans. Unlike the home position depicted in  FIG. 1 , in a swap position the fan stop plate  102  may unblock the first fan  310  or the fan cradle  210 . Arrow  513  represents the course of the disposition to the swap position that the cradle biasing mechanism  213  may prefer. 
     The baffle biasing mechanism  103  may mechanically favor orienting the movable baffle assembly  100  in the home position but the first fan  310  or the fan cradle  210  may block the movable baffle assembly  100  from returning to the home position. According to some embodiments, the baffle biasing mechanism  103  may pivot or rotate from a first position to a second position such as the pivoted and rotated position diagrammatically illustrated in  FIG. 2 . In other aspects, other changes in the mechanical position of the movable baffle assembly  100  may be used to produce the appropriate swap position for a fan while blocking removal of another fan or fans. Arrow  503  represents what may constitute the course of the movable baffle assembly  100  to the preferred disposition of the baffle biasing mechanism  103  but for the movable baffle assembly  100  being blocked by fan cradle  210  identified by circle  600 . Thus, the embodiment depicted in a swap position in  FIG. 2  includes an apparatus that can direct airflow when removing and replacing a fan while also providing for removal of only one fan at a time. 
       FIG. 3  is a flowchart showing operation  700  in accordance with an embodiment to remove and replace an existing fan in an array of fans. When a fan fails, an operator may replace the failed fan. The operator may manipulate a baffle assembly to set it to a swap position  710 . Setting to the swap position  710  may include moving the baffle assembly from the home position shown in  FIG. 1  to the swap position shown in  FIG. 2 . The manipulation may occur to move the movable baffle assembly  100  in either direction, towards fan cradle  210  or towards fan cradle  220 , depending on which corresponding fan may need removal. The manipulation may stabilize or lock into place the movable baffle assembly  100 . The stabilization or locking may utilize a detent or clip. The manipulation may result in directing airflow from a manner such as  420  in  FIG. 1  to a manner such as  421  or  422  in  FIG. 2 . The manipulation may continue to restrict access to an existing fan such as  320  in  FIG. 2 . The manipulation may pivot the fan stop plate  102  out of the way to enable the cradle biasing mechanism  213  to orient a fan cradle  210  in its favored swap position, permitting access to an existing fan such as  310  in  FIG. 2 . 
     The operator may substitute a replacement fan for an existing fan in an array of fans. The operator may remove a nonoperational fan  720  in an array of fans. The removal may occur in the swap position shown in  FIG. 2 . The operator may complete the removal manually. The operator may install a new fan  730  in place of the fan removed. The installation may occur in the swap position shown in  FIG. 2 . The operator may complete the installation manually. The operator may manipulate a fan cradle to set it to a home position  740 . Setting to the home position  740  may include orienting a fan cradle such as  210  from the swap position shown in  FIG. 2  to the home position shown in  FIG. 1 . The manipulation may enable a baffle biasing mechanism  103  to orient the movable baffle assembly  100  in the home position as the fan cradle may no longer block the movable baffle assembly  100  from its favored home position. The movable baffle assembly  100  in the home position restricts access to existing fans such as  310  and  320  in  FIG. 2 . The orientation may stabilize or lock into place the movable baffle assembly  100 . The stabilization or locking may utilize a detent or clip. The manipulation may result in directing airflow from a manner such as  421  or  422  in  FIG. 2  to a manner such as  420  in  FIG. 1 . 
     In other embodiments, the movable baffle assembly may perform the same function of directing or redirecting airflow from multiple cooling fans while allowing removal and replacement of a particular fan unit. Embodiments may exist with more fans and more fan cradles. For example, an embodiment may include a pair of fans on either side of the movable baffle assembly.