Patent Publication Number: US-2022228603-A1

Title: Air filtration ceiling fan

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/392,043, filed on Apr. 23, 2019, which claims the benefit of U.S. Provisional Patent Application No. 62/661,479, filed Apr. 23, 2018, the entire contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     Ceiling fans are commonly used to circulate air through a room. Ceiling fans attach to a ceiling and typically have wiring that passes through a vertical downrod or shaft to power a motor of the ceiling fan. Blades of the ceiling fan are turned by the motor, which push air to move the air through the room. 
     SUMMARY 
     An illustrative air filtration ceiling fan apparatus includes a ceiling fan unit and an air filtration unit. The ceiling fan unit includes a motor and a plurality of fan blades operably coupled to the motor. The air filtration unit includes a filter element and a filter fan configured to move air through the filter element. The ceiling fan unit is operably connected to the air filtration unit to form the air filtration ceiling fan, and the air filtration ceiling fan is configured to attach to a ceiling. 
     An illustrative air filtration apparatus includes a housing, a filter element within the housing, an air intake, and an exhaust port. The air filtration apparatus further includes a filter fan configured to move air into the housing through the air intake, through the filter element, and out of the housing through the exhaust port. The air filtration apparatus is also configured to attach to a ceiling fan. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an example air filtration ceiling fan with an air intake on the bottom of an air filtration unit of the air filtration ceiling fan. 
         FIG. 2A  is a perspective view of an example air filtration ceiling fan with a ring light. 
         FIG. 2B  is a perspective view of an example ceiling fan with a three-light configuration. 
         FIG. 2C  is a perspective view of an example air filtration ceiling fan with a three-light configuration. 
         FIG. 2D  is a perspective view of the example air filtration ceiling fan of  FIG. 2C  showing an example air flow through an air filtration unit. 
         FIG. 3  is a partially-exploded perspective view of a portion of an example air filtration ceiling fan. 
         FIG. 4A  illustrates a simulated airflow analysis of the air filtration ceiling fan of  FIG. 1  based on the blades of the fan rotating in a first direction. 
         FIG. 4B  is an enlarged view of a portion of the analysis of  FIG. 4A . 
         FIG. 5A  a simulated airflow analysis of the air filtration ceiling fan of  FIG. 1  based on the blades of the fan rotating in a second direction. 
         FIG. 5B  is an enlarged view of a portion of the analysis of  FIG. 5A . 
         FIG. 6A  is a partial cross-sectional view of an example air filtration ceiling fan, illustrating air exhaust flow vectored upwards through a vertical flow channel in a ceiling fan unit of the air filtration ceiling fan. 
         FIG. 6B  is a partial cross-sectional view of an alternate example air filtration ceiling fan, illustrating air exhaust flow vectored upwards through a vertical flow channel in a ceiling fan unit of the air filtration ceiling fan. 
         FIG. 6C  is a top view of the air filtration ceiling fan of  FIG. 6B . 
         FIG. 7  is a partial cross-sectional view of an example air filtration ceiling fan with an air filtration unit fan positioned within a ceiling fan unit of the air filtration ceiling fan. 
         FIG. 8A  is a partial side view of an example air filtration ceiling fan with a diverting structure on a fan blade. 
         FIG. 8B  is a partial perspective view of the air filtration ceiling fan with the diverting structure of  FIG. 8A . 
         FIG. 9  is partial side view of an example air filtration ceiling fan with a diverting structure on a housing of a ceiling fan unit. 
         FIG. 10  is a cross-sectional view of an example downrod for an air filtration ceiling fan. 
         FIG. 11A  is a perspective view of an example air filtration ceiling fan with an air intake at the top of an air filtration unit of the air filtration ceiling fan. 
         FIG. 11B  is a side view of the example air filtration ceiling fan of  FIG. 11A . 
         FIG. 12A  is a perspective view of an air filtration ceiling fan with fan blades of a first type. 
         FIG. 12B  is a perspective view of an air filtration ceiling fan with fan blades of a second type. 
         FIG. 13  is a partially-exploded perspective view of a portion of an air filtration ceiling fan with a removed filter element. 
         FIG. 14A  illustrates a simulated airflow analysis of the air filtration ceiling fan of  FIG. 11A  based on the blades of the fan rotating in a first direction. 
         FIG. 14B  is an enlarged view of a portion of the analysis of  FIG. 14A . 
         FIG. 15A  illustrates a simulated airflow analysis of the air filtration ceiling fan of  FIG. 11A  based on the blades of the fan rotating in a second direction. 
         FIG. 15B  is an enlarged view of a portion of the analysis of  FIG. 15A . 
         FIG. 16A  is a top perspective view of an air filtration unit with an air intake at the top of an air filtration unit. 
         FIG. 16B  is a partially-exploded top perspective view of the air filtration unit of  FIG. 16A . 
         FIG. 17  is a cross-sectional view of the air filtration unit of  FIG. 16A . 
         FIG. 18A  is a bottom perspective view of the air filtration unit of  FIG. 16A . 
         FIG. 18B  is an exploded perspective view of the air filtration unit of  FIG. 16A   
         FIG. 19  illustrates examples of three different impeller-style filter fans. 
     
    
    
     DETAILED DESCRIPTION 
     Described herein are various embodiments of assemblies comprising a filter fan assembly (or air filtration unit) and a ceiling fan assembly (ceiling fan unit), combined into a single air filtration ceiling fan. The combined air filtration unit (AFU) and ceiling fan unit (CFU) advantageously may have a symbiotic relationship. For example, the function of the AFU may benefit from having a larger CFU (that is, larger relative to the AFU) circulate air throughout the room, thereby exposing more air to the AFU to be filtered and moving filtered air throughout the room. The function of the CFU may benefit from the air in the room being filtered, thereby reducing the amount of dust in the room. This may reduce the amount of dust that may collect on the ceiling fan blades, and further may prevent dust from collecting on or entering the housing/motor components of the CFU. 
     Positioning the AFU on the ceiling—as opposed to other locations in the room—may also provide advantages. By attaching the AFU to a ceiling fan, the AFU may be positioned centrally in a room and above all furnishings and other items in the room. This positioning may enable efficient air circulation and filtering, as the AFU is distanced from furnishings or other items that may block air flow to or from the AFU. Furthermore, attaching an AFU to a ceiling fan also may position the AFU in a central location of the room without occupying floor space or otherwise displacing a furnishing or item that is desired to be at the center of the room. The placement of the AFU centrally also enables efficient airflow and filtering throughout the room. 
     Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the drawings, like reference numerals refer to the same or similar features. First, with respect to  FIGS. 1, 2A-2D, and 3 , example air filtration ceiling fans with an air intake on the bottom of an AFU will be described. With respect to  FIGS. 4A, 4B, 5A, and 5B , computer flow analyses of example air filtration ceiling fans with an air intake on the bottom of an AFU will be described. With respect to  FIGS. 6A, 6B, and 6C , example air filtration ceiling fans with an air exhaust flow vectored upwards through a vertical flow channel in a CFU will be described. With respect to  FIG. 7 , an example air filtration ceiling fan with an AFU fan positioned within a CFU will be described. With respect to  FIGS. 8A, 8B, and 9 , air filtration ceiling fans with diverting structures will be described. With respect to  FIG. 10 , an example downrod for an air filtration ceiling fan will be described. With respect to  FIGS. 11A, 11B, 12A, 12B, 13, 16A, 16B, 17, 18A, and 18B , an example air filtration ceiling fan with an air intake at the top of an AFU will be described. With respect to  FIGS. 14A, 14B, 15A, and 15B , computer flow analyses of example air filtration ceiling fans with an air intake at the top of an AFU will be described. Finally, with respect to  FIG. 19 , examples of three different impeller style filter fans will be described. 
       FIG. 1  shows a ceiling fan  100  including an air filtration module, in accordance with various embodiments.  FIGS. 2A, 2C, and 2D  show other embodiments that are functionally similar to, but aesthetically different from the embodiment of  FIG. 1 .  FIG. 2B  shows an example ceiling fan without an air filtration unit. 
     The ceiling fan  100  includes a ceiling fan unit  110  (CFU) that may include conventional ceiling fan components, such as a fan motor and blade attachments. The ceiling fan  100  also includes an attachment mechanism  190  for attaching the ceiling fan  100  to the ceiling. The attachment mechanism  190  may attach, for example, to a junction box, such that wiring to power and/or control a motor of the ceiling fan and a filter man may be connected. Such wiring may pass through a downrod of the attachment mechanism  190  to the CFU  110 . The ceiling fan  100  also includes an air filtration unit  120  (AFU) positioned below and mechanically and operably coupled to the CFU  110 . In other words, the AFU  120  is attached to the CFU  110  on a side of the CFU  110  opposing the attachment mechanism  190 . In other embodiments, the AFU  120  may be positioned above the CFU  110 . In other embodiments, components of the CFU  110  and the AFU  120  may also exist in a common housing, such that the CFU  110  and the AFU  120  are not above or below one another. 
     As shown in  FIG. 1 , the AFU  120  intakes ambient air (as illustrated by the upward-oriented arrows) through an air intake  130  located on and/or proximate to a bottom surface of the AFU  120 . The AFU  120  exhausts ambient air (as illustrated by the laterally-oriented arrows in  FIG. 1 ) through an exhaust port  140  (which may comprise, for example, a series of small slots) located on a sidewall of the AFU  120 . The AFU  120  of  FIG. 1  is generally cylindrical in shape, and thus the exhaust port  140  may extend all the way around the circumference of the AFU  120  (e.g., around the entirety of a sidewall defining that circumference). Alternately, the exhaust  140  may be positioned on either a diagonal wall bridging the sidewall and upper surface of the AFU  120 , or solely on an upper surface of the AFU  120  proximate to the CFU  110 . In some embodiments, such arrangements may have some separation between the AFU  120  and CFU  110  to enable adequate passage of air from the AFU  120  exhaust port  140  to the surrounding ambient environment. It should be appreciated that a variety of fan types (including impeller and axial fan types) may support the directional flow patterns illustrated in  FIG. 1 . 
     Although the flow pattern of  FIG. 1  shows air moving in a single direction, the air through the AFU  120  may alternately move in the opposite direction. In some embodiments, a filter fan of the AFU  120 , or any of the other example AFUs described herein, may be operated to selectively rotate in multiple directions, such that air may be directed through the AFU in either direction, as desired. Control of the filter fan may be independent of control of the ceiling fan motor or may be tied to control of the ceiling fan motor. For example, if the AFU is only configured to move air in a single direction, it may operate independently if it can be turned on or off (or have a speed adjusted) without the operation of the ceiling fan motor changing. The control of the filter fan may be tied to the ceiling fan motor if it is only turned on or off (or its speed adjusted) when the ceiling fan motor operation is changed. In another example, control of the filter fan may be tied to the ceiling fan motor where the direction in which the filter fan moves air through the AFU changes when a direction that the ceiling fan motor rotates is changed. In some embodiments, an AFU may be more or less efficient operating to move air in a particular direction based on the direction the ceiling fan motor is rotating. Accordingly, the ceiling fan motor and the filter fan motor directions may be tied together so that the AFU operates in a more efficient manner. 
       FIG. 2A  shows an example air filtration ceiling fan with a ring light  200 . An air intake  210  of the example of  FIG. 2A  is within the bounds of the ring light  200 .  FIG. 2B  shows an example ceiling fan without an AFU. Such an example with three lights can also be implemented with an AFU, as demonstrated in  FIGS. 2C and 2D . 
       FIG. 3  is an exploded view of the AFU  120  of  FIG. 1 , in accordance with various embodiments of the present invention. As shown, the AFU  120  may include one or more filter elements  150  positioned to fully or partially intercept air passing from the air intake  130  to the exhaust  140  of the AFU  120 . A filter element edge  170  may be configured to fit radially inside of an intake edge  160 . In some embodiments, the filter element  150  may be positioned in the air flow path between the AFU intake  130  and a filter fan (not visible) to minimize contaminant accumulation on the blades of the AFU fan. Alternately, one or more filter elements  150  may be positioned at any point in the air flow channel between the intake  130  and the exhaust  140 , including within the intake or exhaust ports and/or before/after the filter fan in the flow path. In embodiments in which multiple filter elements  150  are used, those elements  150  may be arranged serially with respect to the flow path so as to increase filtration efficiency. Further, in the case of multiple filter elements  150 , coarser filter elements  150  may be arranged closer to the air intake  130  to prevent larger-sized contaminant particles from accumulating on the surfaces of the finer filter elements  150 . 
     Filter media area is an important consideration for maximizing both the quality of exhausted AFU air and a service (cleaning, replacement) interval for the filter media. In some embodiments, filter area contained within a fixed size frame may be maximized by pressing the filter media into a pleated or corrugated form. Accordingly, the filter element  150 , or any other filter elements described herein may have a pleated or corrugated surface. 
     The AFU  120  may also include certain features to facilitate removal of the filter element  150  from the AFU  120  for the purpose of cleaning and/or replacing. For example, the AFU  120  may include the intake edge  160  that extends up around the filter element edge  170 . The air intake  130  and filter element  150  may be removed together, may be taken to a remote location, and may then be separated for cleaning and replacement of the filter assembly, thereby providing a way for the user to prevent dislodging of accumulated contaminants into areas of the home that need to be kept clean. Because the intake edge  160  may extend up around the filter element edge  170 , some of the accumulated contaminants may be held in place on the filter element  150  by the air intake  130  until the components are taken apart for cleaning. 
     The AFU  120  may also include a lamp  180  for illuminating the space surrounding the AFU  120  and/or CFU  110 . In the illustrated embodiment, a ring-shaped lamp  180  is shown that accommodates the positioning of other elements, specifically the filter element  150  and air intake  130 . However, a variety of other lamp configurations are available to manage the inclusion and positioning of the intake  130 , lamp  180  and other elements. The ability of the lamp  180  to deliver adequate illumination of the associated room is influenced by a number of factors, including: the lumen rating of the bulb and/or LED assembly; the refraction of light from the bulb and/or LED assembly through a lamp cover; and the area of the lamp cover. For instance, a small area lamp cover refracting a fixed lumen lamp output might appear excessively bright to the viewer. Increasing the area of the lamp cover (i.e., diffusing the light) may therefore be a means of softening the appearance of the lighting. In this respect, the choice of lamp cover shape (e.g., ring versus dome, single lamp versus multiple lamps) as well as lumen ratings, etc. may be considered as factors for different embodiments of air filtration ceiling fans that include one or more lights/lamps to reduce excessive strain on a user&#39;s vision. 
       FIGS. 4A and 4B  show a computer-simulated airflow analysis for the fan  100  of  FIG. 1 . The effectiveness of the AFU  120  may be partly dependent upon how its air flow patterns interact with those of the CFU  100 . The computer flow analysis of  FIGS. 4A and 4B  suggest that vectoring the exhaust flow of the AFU  120  to the CFU  110  flow stream increases the overall effectiveness of the product in the filtration of room air. In  FIGS. 4A and 4B , the CFU  110  is circulating air up toward the ceiling. As shown in the detail of  FIG. 4B , the air exhausted is pushed out into the flow being taken up toward the ceiling by the ceiling fan blades, thereby increasing the effectiveness of the AFU. 
       FIGS. 5A and 5B  show a computer flow analysis for an alternate flow pattern. As illustrated, the alternate air flow pattern suggesting less effective room air filtration. In particular, the exhaust air tends to recirculate back to the intake  130  of the AFU  120 , as shown in the detail of  FIG. 5B . A variety of design modifications may be implemented to minimize recirculation, including but not limited to a higher exhaust velocity to impart momentum to the exhaust stream and/or baffling to vector the exhaust air stream away from the intake. In the example of  FIGS. 5A and 5B , the ceiling fan is pushing air down toward the floor, in contrast with  FIGS. 4A and 4B . Accordingly, in some embodiments, AFUs configured in different ways may work more efficiently or less efficiently depending on the direction in which the fan blades are rotated. In some embodiments, the direction in which an AFU moves air (e.g., vertically upward or vertically downward from intake to exhaust) may be changed to adjust accordingly to a direction in which the ceiling fan blades rotate to maximize efficiency of the AFU. 
       FIGS. 6A and 6B  illustrate exhaust flows from an AFU which are vectored upwards through vertical flow channels in the CFU, in accordance with various embodiments of the present invention. In some embodiments, such an exhaust flow may aid efficient air flow in a room and between an AFU and CFU to direct exhaust air up through the CFU above the ceiling fan blades. This exhaust flow may also keep the AFU below the CFU so that the filter elements may be accessed for service, replacement, etc. 
     In  FIG. 6A , an example air filtration ceiling fan  600  includes an air intake  610  through which air may be pulled through a filter element  615  by a filter fan  620 . The air may be pulled into an AFU housing  605  and directed up into a CFU housing and out the top of the CFU. As such, the air may be directed around a rod  640  which connects the filter motor  620  and a CFU fan blade connector  635 . The CFU fan blade connector  635  may be connected to a fan blade  625  via a spoke  660  and a fan blade  630  via a spoke  655 . The fan blades  625 ,  630  may create, at the connection point with the spokes  660 ,  655 , a CFU housing through which exhaust air from the AFU is pushed out the top of the CFU. The CFU fan blade connector  635  may also be connected to a drive shaft  665  and a fan motor  645 . The fan motor  645  may be attached to a ceiling with an attachment mechanism  650  (such as, for example, a downrod, as illustrated in  FIG. 6A ). 
       FIG. 6B  illustrates another example of an air filtration ceiling fan  670  that exhausts air up through a CFU. Air may be drawn up through an air intake  682  and through a filter element  685  into an AFU housing  680  by an impeller  675  (an example type of filter fan). The air may then pass around fan blade spokes  695 ,  696  that are connected to a ring deflector  693 . The ring deflector, also shown from above in  FIG. 6C , creates, in conjunction with other components, a CFU  691  housing that may channel air upward above the ceiling fan blades  690 ,  692 , such that the air is above the blades when it is exhausted. The air may also pass around a fan motor  674 . Advantageously, the embodiments of  FIGS. 6A-6C  may also aid in cooling the fan motor because additional air passes around the fan motor. 
       FIG. 7  illustrates an alternate configuration, according to various embodiments, in which a filter fan  705  is positioned within a CFU  715 . In such an arrangement, the AFU elements may not all be positioned below the CFU  715 . The filter fan  705  may turn a filter drive shaft  725  that rotates fan or impeller blades within an AFU (not pictured). The filter drive shaft  725  may be housed by a shaft  735 , and both the filter drive shaft  725  and shaft  735  may pass through a fan motor  710 . The fan motor  710  may turn a fan drive shaft  730  to rotate fan blades  720  and  740 . The filter drive shaft  725  and shaft  735  may pass through the fan drive shaft  730 . In such an embodiment, the AFU may be smaller because it does not house the filter fan  705 . 
     In various embodiments, the ceiling fan blades and a filter fan may be powered by the same motor. However, it may be desirable for the ceiling fan and filter fan to turn at different rates. Accordingly, one or more gear boxes may be used to adjust the rotational rate of a drive shaft of a shared motor to output a different rotational rate to one or both of the filter fan or the ceiling fan. In some embodiments, even when two motors are used (one for each of the filter fan and the ceiling fan) a gear box may be included that adjusts a rotational rate of the ceiling fan and/or filter fan. In some embodiments, the rotation rates of the ceiling fan and/or filter fan may be varied (e.g., low, medium, high). Such speeds may be implemented by applying different levels of power to the respective or shared motors, and/or may be adjusted using different gears of a gear box. As described herein, the ceiling fan and the filter fan may be controlled independently or together, including for setting rotation rates of the filter fan and ceiling fan. 
       FIG. 8A  is a partial side view, and  FIG. 8B  is a partial perspective view, of a fan  800  including a diverting structure  820 , according to various embodiments of the present invention. As shown, a fan blade  810  connected to the CFU  800  has a flow diverting structure  820 . The flow diverting structure  820  may create additional air flow due to the rotation of the CFU main blades  810 , thereby distributing AFU exhaust air into the room more effectively. The diverting structure  820  may be shaped differently than the rest of the fan blade  810 , such that exhaust air from an AFU is specifically diverted by the diverting structure  820  to better distribute the air into the room and/or into the air flow created by the rest of the fan blade  810  (or the other fan blades not pictured). In particular, the example diverting structure  820  of  FIGS. 8A and 8B  have a narrower portion  830  at the bottom of the diverting structure  820 . Various configurations of diverting structures may be used in alternate embodiments. In some embodiments, diverting structures may also be used to divert air toward an intake of an AFU (rather than diverting exhaust air away from an AFU). In various embodiments, a respective diverting structure  820  may be provided on one or two or more (e.g., all) fan blades of a fan. 
       FIG. 9  is a partial side view of a fan  900  including a diverting structure  930 , according to various embodiments of the present invention. As shown, a ceiling fan motor housing  915  (attached to the ceiling by a downrod  910 ) of the CFU includes a flow diverting structure  930 . Such a flow diverting structure  930 , in conjunction with an AFU  905  exhaust on the top of the AFU  905 , would deflect vertically upward flowing AFU exhaust air into the CFU stream (e.g., a stream created by rotation of a fan blade  920  connected to the ceiling fan motor by a spoke  925 ). Other diverting structures attached to a ceiling fan motor housing may also be used in other embodiments. 
     Comparing  FIGS. 8A-B  to  FIG. 9 , it should be appreciated that the diverting structure in  FIG. 9  would be effective regardless of whether the CFU  110  is on (i.e., blades rotating) or off, whereas the diverting structure in  FIGS. 8A-B  may be effective only when the CFU  110  is on. 
       FIG. 10  is a cross-sectional view of a downrod  1000  for a ceiling fan, in accordance with various embodiments of the present invention. Most ceiling fans utilize a stationary and hollow vertical downrod or shaft to affix a ceiling fan to a ceiling. A typical downrod also serves as a hollow conduit for electrical wiring between the junction box and the CFU for the operation of motors and lights. As shown in  FIG. 10 , a downrod  1000  according to various embodiments includes an extruded center portion  1010 . The center portion  1010  includes an exterior groove  1020  in which wiring  1030  may be routed, rather than through a centrally positioned hollow passage through the shaft. An outer tube  1040  may then be provided to conceal the wiring  1030  for aesthetic and safety purposes. Such a configuration may provide for a downrod that is stronger and may hold more weight relative to a hollow downrod, which may be advantageous for the various embodiments described herein, where an air filtration ceiling fan would have more weight and components than a typical ceiling fan. 
       FIGS. 11A and 11B  are perspective and side views, respectively, of a ceiling fan  1100  including an air filtration module, in accordance with various embodiments.  FIGS. 12A and 12B  show other embodiments with air filtration units (AFUs) that are functionally similar to, but aesthetically different from the embodiment of  FIGS. 11A and 11B , and also have differently styled fan blades. With reference to  FIG. 11A , the fan includes a CFU  1110  and an AFU  1120  positioned below the CFU  1110 . Alternately, the AFU  1120  may be positioned above the CFU  1110 . 
     As shown in  FIG. 11B , the AFU  1120  intakes ambient air through an air intake  1130  located on and/or proximate the top surface of the AFU  1120 . The AFU  1120  laterally and/or downwardly exhausts air through an exhaust port  1140  located on the bottom surface of the AFU  1120 . In other embodiments, the exhaust  1140  might be positioned on either a diagonal wall bridging the side wall and lower surface of the AFU  1120 , or solely on the side surface of the AFU  1120 . The style of intake described above may receive air through a gap between the CFU  1110  and AFU  1120 , and/or through vertically oriented passageways through the CFU  1110 . In the example of  FIGS. 11A and 11B , a gap does exist between the CFU  1110  and the AFU  1120 . 
     It should be appreciated that a variety of fan types (including impeller and axial fan types) may support the directional flow patterns illustrated in  FIG. 11B . As described herein, various embodiments of filter fans may also support reversing the flow patterns shown by reversing the direction in which the filter fan rotates. 
       FIG. 13  is a partial view of a fan  1100  with a filter assembly  1170  illustrated exploded, in accordance with various embodiments. The AFU  1120  includes one or more filter elements  1150  that are positioned to fully or partially intercept air passing from the intake  1130  to the exhaust  1140  of the AFU  1120 . The filter element may be positioned in the air flow path between the AFU intake  1130  and the internal AFU filter fan to minimize contaminant accumulation on the blades of the fan. Alternately, filter elements  1150  can be positioned at any point in the air flow channel between the intake  1130  and the exhaust  1140 , including within the intake or exhaust ports, and/or including both before and after the filter fan. Where multiple filter elements  1150  may be used, those elements may be arranged serially with respect to the flow path. In the case of multiple filter elements  1150 , the coarser elements may arranged closer to the air intake  1130  to prevent larger-sized contaminant particles from accumulating on the surfaces of the finer elements. 
     The AFU  1120  may include one or more features to facilitate the removal of the filter element  1150  therefrom for the purpose of cleaning and/or replacing. A laterally sliding integrated filter media and filter assembly  1170  is shown in  FIG. 13 . In the example of FIGS.  11 A,  12 A,  12 B, and  13 , contaminants are expected to accumulate solely or largely on the top surface of the filter media  1150 , thereby remaining on the filter media  1150  upon and after removal of the filter media  1150  from the AFU  1120 . The assembly  1170  may be removed together then taken to a remote location for cleaning and replacement. The assembly  1170  also defines a space  1155 , such that an edge  1175  serves as a handle for easily removing and/or replacing the filter assembly  1170 . Advantageously, the filter assembly is also removable from the AFU  1120  in a lateral movement manner, such that the filter assembly does not have to be turned vertically or upside down during removal (or at any time before cleaning, for that matter), which may displace particles from the filter media  1150  during removal. 
     Again referencing  FIGS. 11A, 12A and 12B , a lamp  1180  may be included for illumination of the space surrounding the AFU  1120  and/or CFU  1110 . Dome lamps are shown as examples which accommodate positioning of the air intake  1140  around the outside of the lamp (ring lights may also be used and may enable an air intake positioned around the outside of the lamp and/or within the ring-shaped lamp). In general, a variety of lamp configurations may be used to manage the inclusion and positioning of the exhaust  1140 , lamp  1180  and other elements of the fan. 
     Referencing  FIG. 14A and 14B , the effectiveness of an AFU may be partly dependent upon how its air flow patterns interact with those of the CFU. The computer flow analysis of  FIGS. 14A and 14B  illustrate a computer flow analysis of the air filtration ceiling fan of  FIGS. 11A, 11B, and 13 , with the fan blades rotating in first ( FIG. 14A ) and second ( FIG. 14B ) directions. The analysis shown suggests that vectoring the exhaust flow of the AFU to the CFU flow stream increases the overall effectiveness of filtration of room air. In particular the detail of  FIG. 14B  shows that air exhausted out of the AFU is not exhausted back to the air intake, but rather that the air moving into the air intake of the AFU is from the flow of the ceiling fan blades. 
     Referencing  FIGS. 15A and 15B , an alternate air flow pattern is shown suggesting less effective room air filtration. Note the recirculation of exhaust air to the intake of the AFU in the detail of  FIG. 15B . A variety of design implementations may be available to minimize recirculation, including a higher exhaust velocity to impart momentum to the exhaust stream and baffling to vector the exhaust air stream, implementing air diverting structures, reversing flow direction of the AFU, etc. 
       FIG. 16A  illustrates a perspective view of an AFU  1600 . The AFU  1600  may include an attachment mechanism  1615  for attaching the AFU  1600  to a CFU housing, a filter assembly  1610 , and an AFU housing  1605 . The attachment mechanism  1615  may include screw holes  1630  that may slot onto the head of a screw to attach the AFU  1600  to a CFU housing. In various embodiments, other attachment mechanisms may be utilized to attach the AFU  1600  to a CFU housing. A leg  1635  may extend down from the attachment mechanism  1615  to the AFU housing  1605 . The AFU  1600  may have other legs which are not visible in  FIG. 16A . The legs separate the attachment mechanism  1615  from the AFU housing  1605  to define a space between a bottom surface of the attachment mechanism  1615  and the filter assembly  1610  (and, consequently, a space between the filter assembly  1610  and the CFU to which the AFU  1600  is attached). In this way, air may be pulled through the filter assembly into the AFU housing  1605  through the space between the lower surface of the attachment mechanism  1615  and the filter assembly  1610 . 
       FIG. 16B  shows the AFU  1600  with the filter assembly  1610  removed from the AFU  1600  housing  1605 . The filter assembly  1610  may be generally disk shaped, and may have a corrugated or pleated filter element  1660  that has a surface area of most of the filter assembly  1610  to maximize filtering capacity (and the filter element  1660  may also therefore be disk shaped). The filter assembly  1610  may also include a portion that extends radially outward from the filter element  1660  that may include a handle portion  1650 , which provides an easy place for a person to grasp to remove the filter assembly  1610  from the AFU  1600 . In addition, the space between the attachment mechanism  1615  and the filter assembly  1610  provides space for a person to grab the handle portion  1650 . The filter assembly  1610  may also include a feature  1655  that compression fits with the housing  1605  to secure the filter assembly within the housing  1605 . This is advantageous because the AFU  1600  may vibrate from movement of the filter fan in the AFU  1600  and/or from the ceiling fan movement itself. In various embodiments, other features to secure the filter assembly  1610  in the housing  1605  may be utilized. 
       FIG. 17  shows a cross-section of the AFU  1600 . An intake  1725  shows where air may enter through the filter assembly  1610  in between the filter assembly  1610  and the attachment mechanism  1615 . An impeller intake  1720  receives air that has passed through the filter element  1660 . The air is pulled/pushed by impeller blades  1745  of an impeller  1740  through impeller exhaust  1715  and into exhaust ports  1760  formed by the housing  1605  and/or the exhaust grate  1710 . An impeller-type fan may be used to provide less turbulence than an axial fan of a similar flow rate rating, providing superior power efficiency and lower noise, in some embodiments. The housing  1605  also may include a flare  1735  that extends outward away from an axis of the cylindrically shaped AFU  1600 . This flare  1735  may impart a lateral flow vector component on the exhaust flow of air, thereby promoting the combination of at least a portion of AFU exhaust air with a CFU air flow pattern. Also shown in  FIG. 17  is an opening  1770  in the leg  1635  through which wiring may pass from the CFU to the impeller  1740  and/or a light  1705 . 
     Dimension A of  FIG. 17  represents an air intake clearance height between the bottom of the attachment mechanism  1615  and the top of the intake  1725  where air is drawn into the filter assembly  1610 . Dimension B of  FIG. 17  represents a height or thickness of the filter element  1660  of the filter assembly  1610 . Dimension C of  FIG. 17  represents a fan inlet clearance height that corresponds with the bottom of the filter element  1660  of the filter assembly  1610  and the top of the impeller  1740  (and corresponds with the impeller intake  1720 ). The air intake clearance height (dimension A), the height/thickness of the filter element  1660  (dimension B), and/or the fan inlet clearance height (dimension C) may impact airflow filtration efficiency of the AFU  1600 . In order to achieve efficient airflow through the AFU  1600 , the air intake clearance height (dimension A) may be, for example, anywhere from one-eighth of an inch (⅛th in.) or 3.175 millimeters (mm) to one and a half inches (1½ in.) or 38.1 mm. For example, the air intake clearance height (dimension A) may be any of ⅛th in. (3.175 mm), ¼th in. (6.35 mm), ⅜th in. (9.525 mm), ½ in. (12.7 mm), ⅝th in. (15.875 mm), ¾th in. (19.05 mm), ⅞th in. (22.225 mm), 1 in. (25.4 mm), 1⅛th in. (28.575 mm), 1¼th in. (31.75 mm), 1 ⅜th in. (34.925 mm), or 1½ in. (38.1 mm). In order to achieve efficient airflow through the AFU  1600 , the height/thickness of the filter element  1660  (dimension B) may be, for example, anywhere from one inch (1 in.) or 25.4 mm to four inches (4 in.) or 101.6 mm. For example, the height/thickness of the filter element  1660  (dimension B) may be any of 1 in. (25.4 mm), 1¼th in. (31.75 mm), 1½ in. (38.1 mm), 1¾th in. (44.45 mm), 2 in. (50.8 mm), 2¼th in. (57.15 mm), 2½ in. (63.5 mm), 2¾th in. (69.85 mm), 3 in. (76.2 mm), 3¼th in. (82.55 mm), 3½ in. (88.9 mm), 3¾th in. (95.25 mm), or 4 in. 101.6 mm. In order to achieve efficient airflow through the AFU  1600 , the fan inlet clearance height (dimension C) may be, for example, anywhere from one-sixteenth of an inch ( 1/16th in.) or 1.5875 mm to six inches (6 in.) or 152.4 mm. For example, the fan inlet clearance height (dimension C) may be any of 1/16th in. (1.5875 mm), ⅛th in. (3.175 mm), 3/16th in. (4.7625 mm), ¼th in. (6.35 mm), 5/16th in. (7.9375 mm), ⅜th in. (9.525 mm), 7/16th in. (11.1125 mm), ½in. (12.7 mm), ⅝th in. (15.875 mm), ¾th in. (19.05 mm), ⅞th in. (22.225 mm), 1 in. (25.4 mm), 1⅛th in. (28.575 mm), 1¼th in. (31.75 mm), 1⅜th in. (34.925 mm), 1½ in. (38.1 mm) 1¾th in. (44.45 mm), 2 in. (50.8 mm), 2¼th in. (57.15 mm), 2½ in. (63.5 mm), 2¾th in. (69.85 mm), 3 in. (76.2 mm), 3¼th in. (82.55 mm), 3½ in. (88.9 mm), 3¾th in. (95.25 mm), 4 in. or (101.6 mm), 4¼th in. (107.95 mm), 4½ in. (114.3 mm), 4¾th in. (120.65 mm), 5 in. (127 mm), 5¼th in. (133.35 mm), 5½ in. (139.7 mm), 5¾th in. (146.05 mm), or 6 in. (152.4 mm). 
       FIG. 18A  provides a bottom view of the AFU  1600 . The lamp  1705  is a centrally positioned dome-like structure that provides sufficient space outside of its perimeter for the exhaust ports  1760  of the AFU  1600 . 
       FIG. 18B  is an exploded view of the AFU  1600  illustrated in  FIGS. 16A, 16B, 17, and 18A . In particular, as illustrated in  FIG. 18B , the attachment mechanism  1615  may be disposed on to the top of the housing  1605 , the filter assembly  1610  may be disposed in the housing  1605 , and the impeller  1740  may be disposed inside the housing  1605 . Additionally, the exhaust grate  1710  may be attached to the housing  1605  at the bottom of the housing  1605  (e.g., at a surface that would be below the CFU), and the lamp  1705  attaches to a side of the exhaust grate  1710  opposing the side of the exhaust grate  1710  to which the housing  1605  attaches. 
       FIG. 19  illustrates 3 types of an impeller style fan. A backward-swept fan blade, shown at the top of  FIG. 19 , may generally provide quieter operation than would a straight fan blade (bottom of  FIG. 19 ) or forward-swept fan blade (middle of  FIG. 19 ), and may therefore be used where noise reduction is desired. 
     Various feature types and their variations may be used in CFUs, AFUs, and combined CFU/AFU units. For example, minimum efficiency reporting value (MERV) 6, 8, 11, and/or 13 type filters may be used. In addition, active carbon may be used for odor control in a filter element. Alternating current (AC) or direct current (DC) motors may be used for the ceiling fan and/or filter fan motors. An AC motor may have, for example, three speeds (high, medium, low) and an off setting. A DC motor, for example, may be quieter and may have a greater number of speed settings/range (e.g., a 1-9 range speed settings). The lamp of an air filtration ceiling fan may be a light emitting diode (LED), for example, such as a single brightness (on/off) LED, a dimmable LED, a color change white LED (e.g., 2700K to 7000K), or a color change red/green/blue (RGB) LED. The AFUs described herein may also be used with different fan types and styles, including being optimized for fans with varying blade types. Other features may also be implemented with the air filtration ceiling fans described herein, including implementing an indicator for a dirty fan (e.g., an indicator that the filter should be changed), wireless (e.g., internet, Bluetooth, infrared) connectivity to control ceiling and/or filter fan and/or monitor filter dirtiness, etc. 
     While this disclosure has described certain embodiments, it will be understood that the claims are not intended to be limited to these embodiments except as explicitly recited in the claims. On the contrary, the instant disclosure is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the disclosure. Furthermore, in the detailed description of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it will be obvious to one of ordinary skill in the art that apparatuses, systems, and methods consistent with this disclosure may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure various aspects of the present disclosure.