Patent Publication Number: US-9410716-B2

Title: Ventilation apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a Continuation-In-Part of prior U.S. patent application Ser. No. 13/597,476, which claims priority under 35 U.S.C. §119 to Korean Application No. 10-2011-0088645 filed on Sep. 1, 2011 and 10-2011-0092643 filed on Sep. 14, 2011, whose entire disclosures are hereby incorporated by reference. 
    
    
     BACKGROUND 
     1. Field 
     This relates to a ventilation apparatus. 
     2. Background 
     In general, a ventilation apparatus may supply exterior air to an interior space and exhaust interior air to the exterior, and may minimize interior heat loss by performing heat-exchange between the interior air and the exterior air. Such a ventilation apparatus may include an exhausting blower exhausting interior air to the exterior, an air-supplying blower supplying exterior air to the interior, and a heat transfer heat exchanger performing heat-exchange between the interior air exhausted by the exhausting blower and the exterior air air-supplied by the air-supplying blower. Such a ventilation apparatus may be, for example, embedded into a ceiling, with a ceiling insert type ventilation apparatus connecting the interior and the exterior by ducts to exhaust the interior air to the exterior through the ducts and to supply the exterior air to the interior through the ducts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein: 
         FIG. 1  is a perspective view of a ventilation apparatus in accordance with an embodiment as broadly described herein. 
         FIG. 2  is a disassembled perspective view of the ventilation apparatus shown in  FIG. 1 . 
         FIG. 3  is a front interior view of the ventilation apparatus shown in  FIGS. 1 and 2 . 
         FIG. 4  is a rear interior view of the ventilation apparatus shown in  FIGS. 1 and 2 . 
         FIG. 5  is a plan view of a service cover and an interior air filter of the ventilation apparatus shown in  FIGS. 1 and 2 . 
         FIG. 6  is a disassembled perspective view of the ventilation apparatus having a front panel thereof separated therefrom. 
         FIG. 7  is a disassembled perspective view of a ventilation apparatus in accordance with another embodiment as broadly described herein. 
         FIG. 8  is a cross sectional view of a plurality of service covers of the ventilation apparatus shown in  FIG. 7 . 
         FIG. 9  is a cross sectional view of a plurality of service covers of a ventilation apparatus in accordance with another embodiment as broadly described herein. 
         FIG. 10  is a disassembled perspective view of a ventilation apparatus in accordance with another embodiment as broadly described herein. 
         FIG. 11  is a disassembled perspective view of a ventilation apparatus, in accordance with an embodiment as broadly described herein. 
     
    
    
     DETAILED DESCRIPTION 
     A ventilation apparatus in accordance with the embodiment shown in  FIGS. 1-5  may include a casing  2  that defines an exterior of the apparatus thereof. The ventilation apparatus may be positioned in a space to be ventilated and may be connected to the exterior by a ventilating duct  3 . The ventilating duct  3  may provide for communication between an interior and an exterior of the casing  2 . The ventilating duct  3  may extend through a wall of a building. A partition  3 ′ may be formed in the inside of the ventilating duct  3  to partition an air supply passage from an exhaust passage in the duct  3 . The casing  2  may include interior air suction ports  4 ,  6 , an interior air discharge port  8 , an exterior air suction port  10  and exterior air discharge ports  12 ,  14 . The ventilation apparatus may suction interior air in through the interior air suction ports  4 ,  6  and may discharge the suctioned interior air to the exterior through the ventilation duct  3 . The ventilation apparatus may suction exterior air in through the ventilation duct  3  and may discharge the suctioned exterior air into the interior through the exterior air discharge ports  12 ,  14 . 
     The casing  2  may include a base  16 , a rear panel  18 , a front panel  20 , and a top cover  22 . 
     The base  16  may define a bottom surface of the ventilation apparatus. The base  16  may include a bottom plate  16 A, a left plate  16 B that protrudes upward from a left end of the bottom plate  16 A, and a right plate  16   c  that protrudes upward from a right end of the bottom plate  16 A. An adjusting leg  17  including a screw portion and a bracket supporting the screw portion may be provided at the base  16 . When the screw portion is turned in one direction, such as, for example, rotated clockwise or counterclockwise, the bracket moves away from the base  16  to adjust (increase) a height of the ventilation apparatus. Inversely, when the screw portion is turned in the opposite direction, the bracket and the base  16  approach each other to adjust (decrease) the height of the ventilation apparatus. 
     The rear panel  18  may define the back surface of the ventilation apparatus, with the interior air discharge port  8  and the exterior air suction port  10  extending therethrough. As shown in  FIG. 4 , the rear panel  18  may be formed so that the interior air discharge port  8  and the exterior air suction port  10  may be vertically spaced apart from each other. For example, the interior air discharge port  8  may be positioned above the exterior air suction port  10 . The ventilation duct  3  may be connected to the rear panel  18  so that the exhaust passage formed above the partition  3 ′ may communicate with the interior air discharge port  8  and the air supply passage formed below the partition  3 ′ may communicate with the exterior air suction port  10 . 
     The front panel  20  may define the front surface of the ventilation apparatus. 
     At least one of the rear panel  18  or the front panel  20  may also include portions thereof that define the lateral side surfaces of the ventilation apparatus. In one embodiment, the rear panel  18  may define the back surface of the ventilation apparatus, and the front panel  20  may define the front surface and both lateral side surfaces of the ventilation apparatus. However, in alternative embodiments, the rear panel  18  may define the back surface and both lateral side surfaces of the ventilation apparatus, and the front panel  20  may define the front surface of the ventilation apparatus. Alternatively, the rear panel  18  may define the back surface of the ventilation apparatus, the front panel  20  may define the front surface of the ventilation apparatus, and portions of the rear panel  18  and the front panel  20  may together define the two lateral side surfaces of the ventilation apparatus. 
     The rear panel  18  may include a back plate  18 A in which the interior air discharge port  8  and the exterior air suction port  10  are formed, a left plate  18 B that protrudes forward from the left end of the back plate  18 A, and a right plate  18 C that protrudes forward from the right end of the back plate  18 A. Further, the front panel  20  may include a front plate  20 A, a left plate  20 B that protrudes backward from the left end of the front plate  20 A, and a right plate  20 C that protrudes backward from the right end of the front plate  20 A. The interior air suction ports  4 ,  6  may be formed in one of the left side surface and/or the right side surface of the casing  2 . In particular, the interior air suction ports  4 ,  6  may be respectively formed in the left and right plate  18 B,  18 C of the rear panel  18 , or in the left and right plate  20 B,  20 C of the front panel  20 , depending on how the front panel  20  and the rear panel  18  are configured. 
     There may be a gap at an area where the front panel  20  contacts the rear panel  18 . When a length of the left and right side plates  20 B,  20 C of the front panel  20  in the front and back direction is greater than a length of the left and right side plates  18 B,  18 C of the rear panel  18  in the front and back direction, a gap between the rear panel  18  and the front panel  20  is not easily seen or noticed in the interior space in which the ventilation apparatus is installed. Thus, in the exemplary embodiment shown in  FIGS. 1-5 , the left and right side plates  20 B,  20 C of the front panel  20  are formed longer in the front and back direction than the left and right side plates  18 B,  18 C of the rear panel  18 , and the interior air suction ports  4 ,  6  are formed in the left and right plates  20 B,  20 C of the front panel  20 . 
     The interior air suction ports  4 ,  6  may be formed at positions corresponding to interior air passages  38 ,  39  to be described later. 
     A top cover  22  may define a top surface of the ventilation apparatus. The top cover  22  may have the exterior air discharge ports  12 ,  14  formed therein. 
     Heat transfer heat exchangers  32 ,  34  may be installed in the casing  2  to perform heat-exchange between the interior air to be exhausted to the exterior and the exterior air to be supplied to the interior. The heat exchangers  32 ,  34  may have exterior air passages  36 ,  37  to guide the flow of the exterior air and interior air passages  38 ,  39  to guide the flow of the interior air. 
     The exterior air passages  36 ,  37  may extend in one direction, for example, vertically. The heat transfer heat exchangers  32 ,  34  may be disposed so that the exterior air is introduced into the bottom surface of the exterior air passages  36 ,  37  and discharged at the top surface of the exterior air passages  36 ,  37 . The interior air passages  38 ,  39  may extend in another direction, for example, horizontally. The heat transfer heat exchangers  32 ,  34  may be disposed so that the interior air is introduced into one of the left or the right side surface thereof and discharged at the other of the left or the right side surface thereof. 
     A front shield member may be positioned at front surfaces of the heat exchangers  32 ,  34 , and a rear shield member may be positioned at rear surfaces of the heat exchangers  32 ,  34 . A plurality of heat transfer members may be disposed between the front shield member and the rear shield member to facilitate heat exchange between the exterior air and the interior air while also partitioning the exterior air passages  36 ,  37  and the interior air passages  38 ,  39 . 
     The exterior air passages  36 ,  37  and the interior air passages  38 ,  39  may be alternately formed in the front and back direction. The left and right surfaces of the exterior air passages  36 ,  37  may be blocked, and the top and bottom surfaces thereof may be opened. The top and bottom surfaces of the interior air passages  38 ,  39  may be blocked, and the left and right surfaces thereof may be opened. 
     An exhaust fan  42  may draw the interior air into the interior air passages  38 ,  39 , and air supply fans  44 ,  46  may draw the exterior air into the exterior air passages  36 ,  37 . 
     The exhaust fan  42  suctions the interior air into the interior air suction ports  4 ,  6 , through the interior air passages  38 ,  39  of the heat transfer heat exchangers  32 ,  34  horizontally, and then, may discharge the interior air through the interior air discharge port  8 . The air supply fans  44 ,  46  suction the exterior air into the exterior air suction port  10 , through the exterior air passages  36 ,  37  of the heat transfer heat exchangers  32 ,  34  vertically, and then, may discharge the exterior air through the exterior air discharge ports  12 ,  14 . 
     A frame  50 , in which at least one of the heat exchangers  32 ,  34 , the exhaust fan  42  and/or the air supply fans  44 ,  46  is disposed, may be provided in the inside of the casing  2 . The frame  50  may be disposed on top of the base  16 , with the rear panel  18  behind the frame  50 , the front panel  20  in the front of the frame  50  and the top cover  22  on top of the frame  50 . In certain embodiments, the heat exchangers  32 ,  34  may be disposed in the frame  50  and the exhaust fan  42  may be positioned next to the heat exchangers  32 ,  34 , in the rear panel  18 , with the air supply fans  44 ,  46  positioned in the frame  50 . 
     The frame  50  may include lower frames  52 ,  54 , vertical frames  80 ,  82 , and upper frames  84 ,  86 . The heat exchangers  32 ,  34  may be fixed into the lower frames  52 ,  54 , vertical frames  80 ,  82 , and upper frames  84 ,  86 . In particular, the heat exchangers  32 ,  34  may be seated on the lower frames  52 ,  54 , and the vertical frames  80 ,  82  and the upper frames  84 ,  86  may limit movement of the heat exchangers  32 ,  34  seated on the lower frames  52 ,  54 . 
     The frame  50  may form exterior air suction passages  56 ,  58  between the heat exchangers  32 ,  34  and the base  16 . 
     The lower frames  52 ,  54  may allow the bottom surfaces of the heat exchangers  32 ,  34  to be spaced apart from the base  16 . The lower frames  52 ,  54  may define the exterior air suction passages  56 ,  58  together with the bottom surface of the heat exchangers  32 ,  34  and the bottom plate  16 A of the base  16 . The exterior air blown from the air supply fans  44 ,  46  passes through the exterior air suction passages  56 ,  58  and may be moved into the exterior air passages of the heat exchangers  32 ,  34 . The lower frames  52 ,  54  may form openings  60 ,  62  that guide the exterior air blown from the air supply fans  44 ,  46  to the exterior air passages  36 ,  37 . The openings  60 ,  62  may be formed in the bottom of the heat exchanger  32 ,  34 . The lower frames  52 ,  54  may include first lower horizontal frames  64 ,  66  disposed on the bottom plate  16 A of the base  16  and second lower horizontal frames  68 ,  70  vertically spaced apart from the first lower horizontal frames  64 ,  66 . The lower frames  52 ,  54  may also include first lower connecting frames  72 ,  74  connecting one end of the first lower horizontal frames  64 ,  66  to a corresponding end of the second lower horizontal frames  72 ,  74  and second lower connecting frames  76 ,  78  connecting the other end of the first lower horizontal frames  64 ,  66  to a corresponding end to a corresponding end of the second lower horizontal frames  68 ,  70 . 
     The vertical frames  80 ,  82  may be arranged vertically with respect to the lower frames  52 ,  54 . The vertical frames  80 ,  82  may form openings  81 ,  83  that guide the interior air from the interior air passages  38 ,  39  to the exhaust fan  42 . 
     The upper frames  84 ,  86  may be disposed on top of the vertical frames  80 ,  82 . The upper frames  84 ,  86  may form openings  85 ,  87  that guide the exterior air from the exterior air passages  36 ,  37  into the interior space. 
     The ventilation apparatus may include interior air filters  88 ,  90  positioned between the interior air suction ports  4 ,  6  and the interior air passages  38 ,  39 . The interior air filters  88 ,  90  may filter the interior air suctioned into the interior air passages  38 ,  39  and prevent foreign substances from entering into the interior air passages  38 ,  39  of the heat transfer heat exchangers  32 ,  34 . If, for example, the interior air is suctioned through the left surfaces of the heat exchangers  32 ,  34 , the interior air filters  88 ,  89  may be positioned between the left surfaces of the heat exchangers  32 ,  34  and the interior air suction ports  4 ,  6 . If instead the interior air is suctioned through the right surfaces of the heat exchangers  32 ,  34 , the interior air filters  88 ,  90  may be positioned between the right surfaces of the heat exchangers  32 ,  34  and the interior air suction ports  4 ,  6 . 
     The frame  50  may include filter frames  92 ,  94  to which the interior air filters  88 ,  90  may be attached/detached. The filter frames  92 ,  94  may include openings  91 ,  93  that guide interior air toward the interior air passages  38 ,  39 . The filter frames  92 ,  94  may include filter guides  96 ,  98  that slidably receive and guide movement of the interior air filters  88 ,  90  in the front and back direction. The filter frames  92 ,  94  may connect the lower frames  52 ,  54  and the upper frames  84 ,  86 . The heat exchangers  32 ,  34  may be fixed by the filter frames  92 ,  94 , the lower frames  52 ,  54 , the vertical frames  80 ,  82 , and the upper frames  84 ,  86 . 
     The air supply fans  44 ,  46  may be positioned next to the lower frame  52 . The frame  50  may further include air supply fan mounts  100 ,  102  in which the air supply fans  44 ,  46  are supported. The air supply fan mounts  100 ,  102  may be coupled with the lower frames  52 ,  54  and vertically positioned in the inside of the casing  2 . 
     The frame  50  may also include a partition plate  112  that partitions an exterior air suction chamber  108  in which the air supply fans  44 ,  46  are positioned, and an interior air exhaust chamber  110  in which the exhaust fan  42  is positioned. The partition plate  112  may prevent mixing of the interior air suctioned from the interior with the exterior air suctioned from the exterior. The exterior air suction chamber  108  may be formed between the bottom plate  16 A of the base  16  and the partition plate  112 . The interior air exhaust chamber  110  may be formed between the top cover  22  and the partition plate  112 . The top surface of the partition plate  112  may form an interior air passage, and the bottom surface of the partition plate  112  may form an exterior air passage. The partition plate  112  may establish an installation space for the air supply fans  44 ,  46  while also allowing space for a maximum height of the heat exchangers  32 ,  34 . The partition plate  112  may include a horizontal plate  114  positioned next to the heat exchangers  32 ,  34  and inclination plates  116 ,  118  extending at an incline from opposite edges of the horizontal plate  114  toward the bottom end of the heat exchangers  32 ,  34 . 
     The frame  50  may include a shield plate  120  positioned between the exhaust fan  42  and the top cover  22  to prevent exterior air discharged at the top of the exterior air passages  36 ,  37  of the heat exchangers  32 ,  34  from flowing backward into the exhaust fan  42 . 
     The ventilation apparatus may also include a controller  122  received on the shield plate  120  and controlling the exhaust fan  42  and the air supply fans  44 ,  46 . The shield plate  120  may include a controller receiving space  121  defined by a bottom plate on which the controller  122  is mounted, side plates extending upward from the bottom plate and spaced apart from the heat exchanger holders  76 ,  78 , and top plate extending outward from the respective side plates to the top of the heat exchanger holders  76 ,  78 . The front surface of the controller receiving space  121  may remain open service of the controller  122 . 
     As shown in  FIG. 2 , the exhaust fan  42  may include a fan housing  130 , a blower  132  in the fan housing  130 , and a motor  136  connected to the blower  132  by a rotation shaft. In certain embodiments, the fan housing  130  may be disposed in the rear panel  18 . An air suction port suctioning the interior air into the inside of the fan housing  130  may be formed in each of the left and right surfaces thereof, and an air discharge port  138  discharging the interior air may protrude backward from the fan housing  130 , in communication with the interior air discharge port  8 . 
     As shown in  FIG. 2 , the air supply fans  44 ,  46  may each include a fan housing  140 , a blower  142  rotating in the fan housing  140 , and a motor  144  disposed in the fan housing  140  and rotating the blower  142 . The fan housing  140  may be disposed in air supply fan mounts  100 ,  102  of the frame  50 . An air suction port suctioning the exterior air into the inside of the fan housing  140  may be formed in each of the front and back surface thereof, and an air discharging port  146  discharging the exterior air may extend outward in a side direction from an outer circumferential thereof, excluding the front and rear surfaces of the fan housing  140  where air suction ports are formed. 
     The ventilation apparatus may include exterior air filters  151 ,  152  that filter the exterior air directed toward the exterior air passages  36 ,  37 . The exterior air filters  151 ,  152  may be disposed at the bottom of the heat exchangers  32 ,  34  to prevent foreign substances from entering into the exterior air passages  36 ,  37  of the heat exchangers  32 ,  34 . The exterior air filters  151 ,  152  may be disposed within the heat exchangers  32 ,  34 , or provided on the lower frames  52 ,  54 . Hereinafter, simply for ease of discussion it will be assumed that the exterior air filters  151 ,  152  are disposed in the heat exchangers  32 ,  34 . The heat exchangers  32 ,  34  may include a plurality of heat transfer members  153 ,  154 , heat transfer member frames  155 ,  156  respectively supporting the plurality of heat transfer members  153 ,  154 , and exterior air filter guides  157 ,  158  in the bottom of the heat transfer member frames  155 ,  156  that allow the exterior air filters  151 ,  152  to be slidably detached, in a front and back direction, from the exterior air filter guides  157 ,  158 . 
     The ventilation apparatus may include a service cover  160  coupled with the frame  50  and covering a front surface of the frame  50 . When separating the front panel  20 , the service cover  160  may remain in place so that the heat exchangers  32 ,  34 , air supply fans  44 ,  46 , and exhaust fan  42  are not exposed to the outside. The service cover  160  may be fastened to the frame  50  by fasteners such as, for example, screws. The filter frames  92 ,  94  may remain exposed with the service cover  160  installed on the frame  50  so that the interior air filters  88 ,  90  may be removed and replaced without separating the service cover  160 . A groove  162  may be formed in front of the controller  122  to allow the controller  122  to be serviced without separating the service cover  160 . 
     In a ventilation apparatus as embodied and broadly described herein, the heat exchangers  32 ,  34  may include the left heat exchanger  32  and the right heat exchanger  34  spaced apart from each other, side by side, in the inside of the casing  2 , with the left air supply fan  44  moving exterior air into the left heat exchanger  32  and the right air supply fan  46  moving exterior air into the right heat exchanger  34 . 
     The left interior air suction port  4  may be formed on the left lateral side of the front panel  20  corresponding to the left heat exchanger  32  and the right interior air suction port  6  may be formed on the right lateral side of the front panel  20  corresponding to the right heat exchanger  34 . 
     The left exterior air discharge port  12  may be formed in the top cover  22  corresponding to the top of the left heat exchanger  32  and the right exterior air discharge port  14  may be formed in the top cover  22  corresponding to the top of the right heat exchanger  34 . 
     In a ventilation apparatus as embodied and broadly described herein, the lower frames  52 ,  54  may include the left lower frame  52  on which the left heat exchanger  32  is seated and the right lower frame  54  on which the right heat exchanger  34  is seated, with the left vertical frame  80  supporting the right side of the left heat exchanger  32  and the right vertical frame  82  supporting the left side of the right heat exchanger  34 , and the left upper frame  84  fixed to the top of the left heat exchanger  32  and the right upper frame  86  fixed to the top of the right heat exchanger  34 . 
     The left filter frame  92  may be connected to the left lower frame  52  and the left upper frame  84 , and the right filter frame  94  may be connected to the right lower frame  54  and the right upper frame  86 . 
     In a ventilation apparatus as embodied and broadly described herein, the left interior air filter  88  may be provided at the left of the left heat exchanger  32  and the right interior air filter  90  may be provided at the right of the right heat exchanger  34 . 
     The left of the partition plate  112  may be connected to at least one of the left lower frame  52  or the left vertical frame  80  and the right of the partition plate  112  may be connected to at least one of the right lower frame  54  or the right vertical frame  82 . 
     The left of the shield plate  120  may be connected to at least one of the left vertical frame  80  or the left upper frame  80  and the right of the shield plate  120  may be connected to at least one of the right vertical frame  82  or the right upper frame  86 . 
     The left exterior air filter  151  may be provided at the bottom of the left heat exchanger  32  and the right exterior air filter  152  may be provided at the bottom of the right heat exchanger  34 . 
       FIG. 5  is a plan view of a service cover and an interior air filter of the ventilation apparatus shown in  FIGS. 1-4 . 
     A width D 1  of the service cover  160 , between the left and right ends thereof, may be shorter than a separation distance D 2  between the left interior air filter  88  in the left filter frame  92  and the right interior air filter  90  in the right filter frame  94 . 
     When separating the front panel  20 , the service cover  160 , the left interior air filter  88 , and the right interior air filter  90  may be exposed. The left interior air filter  88  may be withdrawn at the left end of the service cover  160  without separating the service cover  160  from the frame  50 . Similarly, the right interior air filter  90  may be withdrawn at the right end of the service cover  160  without separating the service cover  160  from the frame  50 . 
     As shown in the disassembled perspective view of  FIG. 6 , the ventilation apparatus may also include a plurality of cover brackets  164 ,  166  coupled to the service cover  160 , and a plurality of panel brackets  168 ,  170  provided on the front panel  20 . In the embodiment shown in  FIG. 6 , the plurality of cover brackets  164 ,  166  are disposed horizontally to reinforce strength of the service cover  160 . The plurality of cover brackets  164 ,  166  may be fixed to the service cover  160  by fasteners such as, for example, screws, or by adhering means such as adhesives, or by welding such as spot welding. The plurality of cover brackets  164 ,  166  may include an upper cover bracket  164  provided closer to the top of the service cover  160  and a lower cover bracket  166  provided in parallel to the upper cover bracket  164  and closer to the bottom of the service cover  160 . 
     The plurality of panel brackets  168 ,  170  may be positioned to correspond to the plurality of cover brackets  164 ,  166 , such as, for example, horizontally to reinforce strength of the front panel  20 , as shown in  FIG. 6 . When installing the front panel  20 , the plurality of panel brackets  168 ,  170  may be inserted into the plurality of cover brackets  164 ,  166 , thereby increasing the strength of the front panel  20  and the service cover  160  and preventing random separation of the front panel  20 . The plurality of panel brackets  168 ,  170  may be fixed to the front panel  20  by the adhering means such as adhesives, or by welding such as the spot welding. The plurality of panel brackets  168 ,  170  may include an upper panel bracket  168  and a lower panel bracket  170 , with the upper panel bracket  168  positioned near the upper cover bracket  164  to contact the upper cover bracket  164  and the lower panel bracket  170  positioned near the lower cover bracket  166  to contact the lower cover bracket  166 . 
     In an alternative embodiment, a separation distance between the plurality of panel brackets  168 ,  170  may be larger than that between the plurality of cover brackets  164 ,  166  so that the plurality of cover brackets  164 ,  166  are positioned therebetween, or a separation distance between the plurality of panel brackets  168 ,  170  may be smaller than that between the plurality of cover brackets  164 ,  166  so that the plurality of panel brackets  168 ,  170  are positioned between the plurality of cover brackets  164 ,  166 . 
     Operation of the ventilation apparatus configured as above will now be described. 
     First, when driving the air supply fans  44 ,  46 , exterior air is suctioned into the exterior air suction chamber  108  through the exterior air suction port  10  and blown into the bottom of the heat exchangers  32 ,  34  by the air supply fans  44 ,  46 . At this point, the moving direction is changed to an upward direction, and foreign substances are filtered from the exterior air by the exterior air filters  151 ,  152 . 
     The exterior air passing through the exterior air filters  151 ,  152  is introduced into the exterior air passages  36 ,  37  through the bottom surface of the heat exchangers  32 ,  34 , undergoes heat-exchange with the interior air passing through the interior air passages  38 ,  39 , and is discharged through the top surface of the heat exchangers  32 ,  34 . The exterior air discharged through the top surface of the heat exchangers  32 ,  34  is directly discharged into the interior space to be ventilated through the exterior air discharge ports  12 ,  14  of the top cover  22 . 
     The moving direction of the exterior air is first horizontally converted in the exterior air suction chamber  108  and is then vertically converted at the bottom of the heat exchangers  32 ,  34 . Therefore, after converting its moving direction twice, the heat-exchanged exterior air is discharged into the interior space. 
     When driving the exhaust fan  42 , the interior air is suctioned from the interior space into the ventilation apparatus through the interior air suction ports  4 ,  6 , where foreign substances are filtered from the interior air by the interior air filters  88 ,  90 . 
     The interior air passing through the interior air filters  88 ,  90  undergoes heat-exchange with the exterior air in the exterior air passages  36 ,  37  while passing through the interior air passages  38 ,  39  of the heat exchangers  32 ,  34 , is suctioned into the interior air exhaust chamber  110 , through the exhaust fan  42 , and is discharged to the outside through the interior air discharge port  8 . 
     The moving direction of the interior air is horizontally converted in the interior air exhaust chamber  110 . Therefore, after converting moving direction only once the interior air is discharged to the outside. 
       FIG. 7  is a disassembled perspective view of a second embodiment of ventilation apparatus as broadly described herein, and  FIG. 8  is a cross sectional view of service covers of the ventilation apparatus shown in  FIG. 7 . 
     As shown in  FIGS. 7 and 8 , a plurality of service covers  200 ,  202 ,  204 ,  206 ,  208  may be mounted on the frame  50  by fasteners, such as screws, and may be separated from the frame  50  by releasing the fasteners. The plurality of service covers may include first service covers  202 ,  204  shielding the front of the heat exchangers  32 ,  34 , and a second service cover  206  shielding the fronts of the air supply fans  44 ,  46  and the exhaust fans  42 . 
     The first service covers  202 ,  204  may prevent the exterior air blown from the air supply fans  44 ,  46  from leaking through the exterior air discharging ports  12 ,  14  through the fronts of the exterior air filters  151 ,  152  and the heat exchangers  32 ,  34 . The exterior air blown from the air supply fans  44 ,  46  may be blocked by the first service covers  202 ,  204  and guided to the exterior air filters  151 ,  152  and the exterior air passages  36 ,  37  of the heat exchangers  32 ,  34  for discharge through the exterior air discharge ports  12 ,  14 . The first service covers  202 ,  204  may prevent the exhaust fan  42  from suctioning interior air through the fronts of the heat exchangers  32 ,  34 . Rather, the interior air suctioned by the exhaust fan  42  is blocked by the first service covers  202 ,  204  and guided to the interior air passages  38 ,  39  of the heat exchangers. The first service covers  202 ,  204  may cover the space between the ends of the vertical frames  80 ,  82  and the filter frames  92 ,  94  and may cover the space between the ends of the upper frames  84 ,  86  of the lower frames  52 ,  54 . The first service covers  202 ,  204  may leave the front of the interior air filters  88 ,  90  exposed so that the interior air filters  88 ,  90  may be serviced without removing the first service covers  202 ,  204 . The first service covers  202 ,  204  may include a first left service cover  202  detachably coupled to the frame  50  and shielding the front of the left heat exchanger  32 , and a first right service cover  204  detachably coupled to the frame  50  and shielding the front of the right heat exchanger  34 . The first service covers  202 ,  204  may shield the fronts of the heat exchangers  32 ,  34  and also the exterior air filters  151 ,  152 . 
     The second service cover  206  may cover the space between the ends of the left lower frame  52  and the right lower frame  54 , the space between the ends of the left vertical frame  80  and the right vertical frame  82 , and the space between the ends of the left upper frame  84  and the right upper frame  86 . The second service cover  206  may also cover the space between the ends of the base  16  and the shield plate  120 . A groove  207  may be formed in the second service cover  206 , in the front of the control box  122 , so that the controller  122  may be serviced without removing the second service cover  206 . 
     The plurality of service covers may further include third service covers  208 ,  210  detachably coupled to the frame  50  and shielding the front of the exterior air suction passages  56 ,  58 . The third service covers  208 ,  210  may prevent the exterior air blown from the air supply fans  44 ,  46  from leaking into the exterior air discharge ports  12 ,  14  through the fronts of the exterior air suction passages  56 ,  58 , the exterior air filters  151 ,  152 , and the heat transfer heat exchangers  32 ,  34 . The exterior air blown from the air supply fans  44 ,  46  is guided to the exterior air suction passages  56 ,  58 , the exterior air filters  151 ,  152 , and the exterior air passages  36 ,  37  of the heat exchangers  32 ,  34  for discharge through the exterior air discharge ports  12 ,  14 . The third service covers  208 ,  210  may cover the front surface of the lower frames  52 ,  54 . The third service covers  208 ,  210  may include a third left service cover  208  shielding the left exterior air suction passage  56  at the bottom of the left heat exchanger  32 , and a third right service cover  210  shielding the right exterior air suction passage  58  at the bottom of the right heat exchanger  34 . The third left service cover  208  may cover the front surface of the left lower frame  52 , and the third right service cover  210  may cover the front surface of the right lower frame  54 . 
       FIG. 9  is a cross sectional of a plurality of service covers of a ventilation apparatus in accordance with a third embodiment. 
     As shown in  FIG. 9 , first service covers  202 ′ and  204 ′ may be detachably coupled to the frame  50  to shield the front of the heat transfer heat exchangers  32 ,  34  while leaving the front of the exterior air filters  151 ,  152  exposed. Third service covers  208 ′ and  210 ′ may be detachably coupled to the frame  50  to shield the fronts of the exterior air suction passages  56 ,  58  and also the exterior air filters  151 ,  152 . 
     In this embodiment, to service the exterior air filters  151 ,  152 , removal of the third service covers  208 ′,  210 ′, which are smaller in size, rather than the first service covers  202 ′,  204 ′, which are larger size, the exterior air filter  151 ,  152  may be more easily accessed. 
       FIG. 10  is a disassembled perspective view of a ventilation apparatus in accordance with a fourth embodiment. 
     Similar to the second and third embodiments, the ventilation apparatus of the embodiment shown in  FIG. 10  may include a plurality of service covers, and the plurality of service covers may include the first service covers  202 ′,  204 ′ and the second service cover  206 ′. 
     Similarly, the first service covers  202 ′,  204 ′ may be detachably coupled to the frame  50  to shield the front of the heat transfer heat exchangers  32 ,  34  and the exterior air filters  151 ,  152  together. Like the second embodiment, the first service covers  202 ′,  204 ′ may be detachably coupled to the frame  50  to shield the fronts of the heat exchangers  32 ,  34  while leaving the fronts of the exterior air filters  151 ,  152  exposed. 
     The second service cover  206 ′ may shield the fronts of the air supply fans  44 ,  46 , the exhaust fan  42 , and the exterior air suction passages  56 ,  58 . When the first service covers  202 ′,  204 ′ shield the fronts of the heat exchangers  32 ,  34  and do not shield the fronts of the exterior air filters  151 ,  152 , the second service cover  206 ′ may shield the fronts of the air supply fans  44 ,  46 , the exhaust fan  42 , the exterior air suction passages  56 ,  58 , and the exterior air filters  151 ,  152 . 
     In the alternative embodiment shown in  FIG. 11 , a frame structure is provided within the casing, the casing including a front panel including a front plate, left plate having an interior air suction port and right plate having an interior air suction port. The front plate, the left plate and the right plate may be respectively formed and assembled together. The embodiment shown in  FIG. 11  includes many of the components shown in the previously described embodiments. As can be seen in  FIG. 11 , connection and assembly of the various frame components may be adjusted for ease of manufacture and assembly. This may also facilitate installation of the various fans and filters and access thereto. 
     In a ventilation apparatus in accordance with various embodiments as broadly described herein, exterior and interior air passages may be simplified, thereby simplifying structures and to enhancing efficiency. The frame may efficiently guide the movement of the interior and exterior air without hindering the interior and exterior air and adding unnecessary flow resistance while also supporting the heat transfer heat exchanger. Further, it is possible to minimize losses of interior air and exterior air that have not passed through the heat transfer heat exchanger, thereby enhancing heat exchange performance of the heat transfer heat exchanger. 
     Additionally, the exterior air filter and/or the interior air filter may be easily accessed for service. 
     In a ventilation apparatus as embodied and broadly described herein, all of an exterior side air passage and an interior side air passage may be formed horizontally, making structures of the air passage complex, with complex internal structures generating large losses. 
     A ventilation apparatus as embodied and broadly described herein may include a base, frames disposed in the base, a rear panel disposed in the back of the frames and formed with an interior air discharge port and exterior air suction port, a top cover disposed in the top of the frame and formed with the exterior air discharge port, a front panel disposed in the front of the frame and formed with the interior air discharge port, a heat transfer heat exchanger disposed in the frame and formed with an interior air passage and an exterior air passage, an exhaust fan moving an interior air into the interior air passage; and an air supply fan moving an exterior air into the exterior air passage, wherein the frames include a lower frame formed with an opening passing the exterior air blown from the air supply fan; a vertical frame vertical to the lower frame and formed with the opening passing the interior air moved from the interior air passage, and an upper frame disposed in the top of the vertical frame and formed with the opening passing the exterior air moved from the exterior air passage. The front panel may be formed with the interior air suction port next to the interior air passage. 
     The ventilation apparatus may also include an exterior air filter, disposed in the bottom of the heat transfer heat exchanger, purifying the exterior air suctioned toward the exterior air passage. 
     The heat transfer heat exchanger may include a plurality of heat transfer members; a heat transfer member frame supporting the plurality of heat transfer members; and an exterior air filter guide detached with the exterior air filter and disposed in the bottom of the heat transfer member frame. 
     The lower frame may enable the bottom surface of the heat transfer heat exchanger to space apart from the base. 
     The ventilation apparatus may also include an interior air filter, disposed between the interior air suction port and the interior air passage, purifying the interior air suctioned into the interior air passage. 
     The frame may be formed with an opening passing the interior air moved toward the interior air passage, and the ventilation apparatus may further include a filter frame detached with the interior air filter. 
     The ventilation apparatus may also include a service cover coupled with the frame and covering the front surface of the frame. 
     The ventilation apparatus may also include a first service cover detached from the frame and shielding the front of the heat transfer heat exchanger; and a second service cover detached from the frame and shielding the fronts of the air supply fan and the exhaust fan. 
     The first service cover may be detached from the frame not to shield the front of the interior air filter. 
     The first service cover may be detached to shield the fronts of the heat transfer heat exchanger and the exterior air filter together. 
     The frame may form the exterior air suction passage suctioned with the exterior air in the bottom surface of the heat transfer heat exchanger between the heat transfer heat exchanger and the base. 
     The second service cover may be disposed to shield the fronts of the air supply fan, the exhaust fan and the exterior air suction passage together. 
     The second service cover may be disposed to shield the fronts of the air supply fan, the exhaust fan, the exterior air suction passage and the exterior air filter together. 
     The ventilation apparatus may also include a third service cover disposed in the frame and shielding the front of the exterior air suction passage. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.