Abstract:
A ceiling damper system that comprises a damper housing having an input opening to accept air from a heating, ventilation and air conditioning HVAC system, and an output opening to supply the HVAC air to a room. The system further comprises a damper mechanism to substantially block the flow of air through the damper housing when the temperature around the housing reaches a predetermined level. Two or more cross members are included, each of which is mounted between fixed points in the ceiling in a position to allow the cross members to support and hold the damper housing. The damper housing rests on the cross members and is mounted to the cross members. A method for mounting a ceiling damper that comprises providing a ceiling damper having a damper housing for accepting air from a HVAC system and providing the HVAC system air to a room. It further comprises mounting at least two cross members across fixed points in a room ceiling in a position to support the damper housing. It then comprises arranging the damper housing on the cross members so that the damper rests on the cross members and is affixed to the cross members in a position to provide HVAC air to the room. HVAC system air is then provided to the ceiling damper.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to dampers and more particularly to fire dampers mounted in ceilings.  
         [0003]     2. Description of the Related Art  
         [0004]     A major consideration in the design of commercial and residential buildings is the spread of fire and smoke in the event that a fire breaks out within the building. The walls and ceilings within the buildings serve as the primary barriers to the spread of fire and are most effective if they have no breaks or openings.  
         [0005]     Most buildings have heating, ventilation, and air conditioning (HVAC) systems that distribute conditioned/heated air throughout the building by air ducts. The ducts carrying either heated or cooled air are directed to various rooms in the building and the air enters the rooms through openings or vents in the ceilings, floors or walls. These openings and vents, however, penetrate the ceiling, floors or walls, providing a hole that reduces the ability to prevent the spread of fire and smoke. To address this problem, dampers are often provided in the ducts or at the openings and vents that allow air to pass when open, but block airflow, flames, and hot gasses when closed. At elevated temperatures (such as in the case of fire) the dampers automatically close, effectively closing the duct and vent holes and restoring the full integrity of the fire and/or smoke barrier.  
         [0006]     One type of conventional ceiling damper used in ceilings, can be arranged between components of the ceiling, such as trusses, joists and TJI beams (referred to collectively as “trusses”). The damper is mounted in the ceiling by a hanging arrangement wherein two or more wires, or some other similar hardware, are connected between the top of the damper and a fixed point above the damper. Ceiling material is mounted to the trusses and serves as the ceiling for the room, with the damper mounted between the ceiling and the top of the structure. The output of the damper is disposed in a hole in the ceiling material and the input is coupled to an HVAC system such that air from the HVAC system passes through the damper and into the room when the damper is open.  
         [0007]     The damper can be hung in the ceiling using many different methods, with a typical method comprising mounting a horizontal angle or wood support stud between adjacent trusses, near the top of the trusses, with the support stud providing a fixed point for connection. The damper is then hung from the horizontal angle or wood support stud by two or more vertical angles or hanger wires that are connected between the damper and the horizontal support stud.  
         [0008]     One disadvantage of hanging a damper in a ceiling is that the ceiling area between the trusses is small. It can be awkward and difficult to install the horizontal angle and wood stud support between the trusses and then hang the damper vertical angles or wires in such a small area. It is also difficult to cut the vertical angles or wires and connect them at the correct length so that the opening of the damper is at the same level as the ceiling material. If the damper is hung at the wrong level, the vertical angles or wire must be adjusted until the hanging height is correct. This can require repeatedly working the small ceiling area between the trusses until the damper is properly installed.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention provides a ceiling damper system that allows a damper to be mounted in a ceiling without hanging and provides a method for installing a ceiling damper without hanging. One embodiment of a ceiling damper system according to the present invention comprises a damper housing having an inlet opening to accept air from a heating, ventilation and air conditioning (HVAC) system, and an outlet opening to supply the HVAC air to a room. The system further comprises a damper mechanism to substantially block the flow of air through the damper housing when the temperature around the housing reaches a predetermined level. Two or more cross members are included, each of which is mounted between fixed points in the ceiling. The cross members are arranged to support and hold the damper housing such that the damper housing rests on the cross members and is mounted to the cross members.  
         [0010]     One embodiment of a method for mounting a ceiling damper according to the present invention comprises providing a ceiling damper having a damper housing for accepting air from a HVAC system and providing the HVAC system air to a room. It further comprises mounting at least two cross members across fixed points in a room ceiling in a position to support the damper housing. The damper housing is arranged on the cross members so that the damper rests on the cross members and is affixed to the cross members in a position to provide HVAC air to the room. HVAC system air is then provided to the ceiling damper.  
         [0011]     These and other further features and advantages of the invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of one embodiment of a damper according to the present invention;  
         [0013]      FIG. 2  is a top view of the damper shown in  FIG. 1 ;  
         [0014]      FIG. 3  is an elevation view of the damper shown in  FIG. 1 ;  
         [0015]      FIG. 4  is an elevation view of the lower left portion of the damper in  FIG. 1 , with a boot rail;  
         [0016]      FIG. 5  is a perspective view of one embodiment of a boot rail according to the present invention;  
         [0017]      FIG. 6  is a sectional view of the damper in  FIG. 1 , taken along section lines  6 - 6 ;  
         [0018]      FIG. 7  is a bottom perspective view of one embodiment of a damper according to the present invention installed in a ceiling using boot rails;  
         [0019]      FIG. 8  is a top perspective view of the damper shown in  FIG. 7 ;  
         [0020]      FIG. 9  is a side elevation view of one embodiment of an installed damper according to the present invention with a connected flex duct; and  
         [0021]      FIG. 10  is a front elevation view of the installed damper shown in  FIG. 9 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]      FIGS. 1-3  and  6  show one embodiment of a damper  10  that can be used in a ceiling damper system according to the present invention. It should be understood that the invention could also be used with many different types of dampers having different shapes and sizes. The damper  10  generally comprises a box shaped lower section  12  and a cylindrical upper damper frame  14 . The lower section  12  and upper damper frame  14  can be made of many different rigid materials, with a suitable material being galvanized steel that is approximately 30 GA.  
         [0023]     The lower section  12  has a square/rectangular shaped opening  16  in its bottom surface  17  and a circular opening  18  in its top surface  19 . The circular opening  18  can be in different locations on the top surface  19 , with a suitable location having the center of the opening  18  aligned with the center of the top surface  19 . The cylindrical damper frame  14  has substantially the same diameter as the circular opening  18  and the damper frame  14  is mounted to the top surface of the lower section  12 , in alignment with the circular opening  18 . The damper frame  14  opens to the interior of the lower section  12  through the circular opening  18 .  
         [0024]     A spring loaded butterfly blade mechanism  20  is mounted within the damper frame  14  and generally comprises two half circle damper butterfly blades  22 ,  24 . The blades  22 ,  24  can be made of many different rigid materials, with a preferred material being galvanized steel that is approximately 22 GA. The radius of each of the half circles is substantially the same and when added together approximately equal the diameter of the upper damper frame  14 . The straight base sections of each of the blades are rotatably mounted to a cross section  25  (shown in  FIGS. 1 and 6 ) such that each of the blades  22 ,  24  can be rotated between a horizontal and vertical position, with the blades  22 ,  24  in the vertical position in  FIGS. 1-3  and  6 . Alternative dampers according to the present invention can comprise a single damper blade or more than two damper blades.  
         [0025]     A closure spring  27  (shown in  FIG. 6 ) is included at the base of each of the blades  22 ,  24  that urges the blades  22 ,  24  to the horizontal position. Many different springs can be used, with a preferred spring being a conventional zinc plated closure spring. When the blades  22 ,  24  are in a horizontal position they form a circle that substantially covers the opening of the damper frame  14 , blocking most air from passing. When the blades  22 ,  24  are held in the vertical orientation, the damper is “open” and air is allowed to pass through it. When they are in the horizontal position, the damper is “closed” and air is prevented from passing.  
         [0026]     As shown in  FIG. 1-3  and  6 , the damper blades  22 ,  24  are held in a vertical “open” orientation by a fuse link  26  mounted between the top of the two blades  22 ,  24 . Fuse links are commercially available and are typically held together by a section that melts at a predetermined temperature such that the fuse link separates into two pieces. The fuse link  26  is arranged between the blades  22 ,  24  with each of the blades  22 ,  24  connected to a respective one of two pieces of the fuse link  26 . At the predetermined ambient temperature, the melting section melts, and the fuse link separates into two pieces. The blades are then no longer held in vertical orientation by the fuse link  26  and the closure spring  25  causes the blades  22 ,  24  to rotate to the horizontal orientation.  
         [0027]     In other embodiments, the fuse link can be positioned in different locations and more than one fuse link can be used. In still other embodiments other devices other than a fuse link can be used which separate a predetermined temperature. Many different commercially available fuse links can be used according to the present invention, with a suitable fuse link provided by Elsie Manufacturing, Inc, Model B. This fuse link has a melting temperature in the range of 165 to 212 degrees Farenheit, although other fuse links with other separation temperatures can be used.  
         [0028]     Referring now to  FIG. 6 , the interior of the lower section  12  can be covered by a layer of thermal insulation  28  that helps maintain the temperature of the air passing through the damper. Different types of insulation material can be used, with a suitable material being fiberglass R-6.0 insulation that is approximately 1½ inches thick. The inside of the cylindrical damper frame  14  can include a blade ledge  30  that runs axially around the inside surface of the cylindrical damper frame  14 . The ledge  30  is at substantially the same height as the bottom of the vertically damper blades  22 ,  24 . When the fuse link  26  separates and the blades  22 ,  24  are moved to the horizontal orientation by the damper spring, the outside edge of the blades  22 ,  24  rest on the ledge  30 . The ledge  30  helps insure that when the fuse link  26  is separated, the blades  22 ,  24  come to rest in a horizontal orientation. The ledge also helps to block air from passing through any space that may be between the outer edge of the blades  22 ,  24  and the inside surface of the damper frame  14 .  
         [0029]     Referring now to  FIGS. 3 through 5 , a damper  10  according to the present invention can be mounted in a ceiling by attachments at the bottom of the damper&#39;s lower section  12 , instead of being hung in place. Accordingly, when installing the damper  10 , the hardware to hang the damper does not need to be installed in the confined area of the ceiling between the trusses. Instead, the installation hardware can be installed at the bottom of the trusses, which can be reached from the interior of the room where the space is generally not confined.  
         [0030]     The damper  10  can be mounted from the bottom in many different ways using many different mechanisms according to the present invention. Any rigid cross-member can be used that can be mounted to fixed points in the ceiling so that the lower section can rest on the cross members without interfering with the flow of HVAC air in or out of the damper. The cross-member should also comprise a mechanism for holding the damper on the cross members.  
         [0031]     A suitable cross member according to the present invention comprises an elongated boot rail  32  that is arranged to cooperate with the bottom surface  17  of the lower section  12 . The boot rail  32  can be mounted in many different ways such as between adjacent trusses, joists or TJI beams (referred to collectively as “trusses”) in a ceiling. As more fully described below, at least two boot rails  32  are needed for the mounting of each damper. After the boot rails  32  are mounted to the damper  10 , the damper is mounted in the ceiling.  
         [0032]     The square/rectangular opening  16  in the lower section&#39;s bottom surface  17  is smaller than the bottom surface  17  so that there is a boot flange  34  between the edge of the opening  16  and the bottom surface&#39;s edge. A boot lip  36  is also included around the bottom surfaces edge that extends horizontally from the boot flange  34 . The boot rail  32  has a generally S-shaped cross section and when mounting the damper  10  on the boot rail, the lip  36  is inserted into and fits within the boot rail&#39;s first section  38  in the direction as shown by arrow  37 . With boot rails on at least two opposing sides of the lower section  12 , the damper  10  is held between the boot rails with the opposing edge lips  36  held in their respective first section  38 . The boot flange  34  rests on the boot rail&#39;s straight section  40 . The outside surface of the lower section  12  butts against the boot rail&#39;s first section  38 .  
         [0033]     A vertical hood  42  is included around the square opening  16  and when ceiling material is installed the edge of the opening in the ceiling material abuts the hood  42  with the bottom edge of the hood  42 . The bottom opening and its hood should be flush with the ceiling material when the damper is installed. When the boot rails are installed, the hood  42  of the opening  16  rests against the boot rails second curved section  44 .  
         [0034]      FIGS. 7 and 8  show the damper  10  mounted on first and second boot rails  50 ,  52  that are affixed between first and second ceiling trusses  54 ,  56 . The damper  10  should be supported by at least two boot rails with the ends of the boot rails  50 ,  52  connected to the trusses. Many different attachment devices can be used such as nails, screws or bolts, with suitable nails being  16 d nails, suitable screws being No. 8 screws, and suitable bolts being 2 inches long. One or more of these mounting devices can be used at each end of the boot rails  50 ,  52 . The boot rails  50 ,  52  can be mounted to many different locations on the trusses, with a suitable location as shown in  FIGS. 7 and 8  being the lower surface of each of the trusses. The boot rails  50 ,  52  can also be mounted at different angles in relation to the trusses  54 ,  56  with a suitable angle being transverse to the trusses  54 ,  56 .  
         [0035]     The boot rails  50 ,  52  should be positioned on the trusses  54 ,  56  so that the first sections (shown in  FIG. 4 ) of the boot rails can mate with the lip and flange of the damper&#39;s lower section to hold the damper. When the damper is installed, the lip (also shown in  FIG. 4 ) along one edge of the lower section mates with the first boot rail  50  and the lip on the lower sections opposite edge mates with the second boot rail  52 . The boot flange along these opposite lower section edges rest on their respective first or second boot rails  50 ,  52 . This arrangement allows the first and second boot rails  50 ,  52  to hold the damper in place by the connection at the bottom of the damper to the boot rails  50 ,  52 .  
         [0036]     The damper  10  can be placed on the boot rails  50 ,  52  after they are installed or the boot rails  50 ,  52  can be positioned on the damper  10  first and then the boot rails  50 ,  52  can be mounted to the trusses. Alternatively, one of the boot rails can be mounted to one of the trusses and the second boot rail can be position on the damper  10 . The damper can then be placed on the mounted first boot rail and the second boot rail can be mounted in place to one of the trusses. There can be many different variations of these mounting procedures depending on the number of boot rails used.  
         [0037]      FIGS. 9 and 10  show part of a ceiling damper system  70  utilizing a damper  72  mounted in a ceiling according to the present invention, although it should be understood that the damper  72  can be used in other systems, such as a simple ventilation system. Boot rails  74 , 76  are mounted to the damper  72  by mating the lower section lip with the boot rails  74 , 76  as described above. The damper  72  is then mounted between trusses  78 , 80  as also described above. The damper  72  is then connected to the HVAC system using a duct  82 . Many different conventional ducts  82  can be used, with the preferred duct being flex duct identified as United Laboratories (UL) classified Air Duct Class 0 or Class 1. The duct can be coupled to the damper&#39;s damper frame using many different coupling methods, with suitable methods being steel clamp, plastic strap or  18  swg steel wire. Air passing through the duct, either heated or cooled, passes into the damper  72 .  
         [0038]     RC channels are typically included as part of a ceiling construction and comprise a steel channel that is attached to the structure so that ceiling panels can be attached. This allows the drywall to be supported by, but not rigidly connected to, the structure. Each damper that is installed is considered a ceiling penetration that can compromise the ability of the ceiling to prevent the spread of fire. When installing a damper  72  according to the present invention, ceiling penetrations should be located between adjacent trusses  78 ,  80  and between RC channels without requiring cuts in the RC channel. If required, one RC channel can be cut to enable proper damper location and installation.  
         [0039]     Once the damper  72  is mounted between the trusses  78 ,  80  on the boot rails  74 ,  76 , ceiling panels  83 , such as drywall or gypsum wall board, can be mounted to the RC channel and/or trusses  78 ,  80  to form the ceiling. A cutout is included in the ceiling material for the bottom opening  84  (also shown as  16  in  FIGS. 1-4  and  6 ) of the damper  72  with the edge of each drywall opening fitting against the edge of the hood damper opening  84 . The distance between the edge of the bottom opening and the edge of the cutout in the ceiling material should not exceed approximately ⅛ of an inch on any side. After the ceiling material is installed, a grille  86  can be fastened to the damper, over the bottom opening  84 . Many different mounting devices can be used, with a preferred mounting device being No.  8  screws. The grille  86  is typically mounted by securing it to the lower section  88  of the damper so the ceiling material is sandwiched between the grille  86  and the lower section  88 .  
         [0040]     In operation, the HVAC system  70  provides heated or cooled air to a room by first passing the air into the duct  82 . The air then passes into the room through the damper  72 . If a fire breaks out in the room below the damper or in the structure around the damper  72 , and if the temperature around the damper exceeds the melting temperature for the fuse holding the blades open, the fuse will separate and the blades will close. This closes the damper and prevents most air from passing through it, which effectively restores the ability of the ceiling to prevent the spread of fire by blocking the hole created for the damper.  
         [0041]     Although the present invention has been described in considerable detail with reference to certain preferred configurations, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the preferred variations described above.