Abstract:
A system for preventing growth of mold and mildew in buildings comprises an air diffusion device covering an opening of a heating ventilation and air conditioning duct. A heating cable is affixed to a flange of the air diffusion device that extends along a periphery of a screen covering the opening. The cable is activated to heat the surfaces of the air diffusion device to a temperature above dew point and prevent condensation.

Description:
[0001]     This application claims priority of Provisional Patent Application Ser. No. 60/498,206, filed on Aug. 26, 2003. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention pertains, generally, to heating ventilation and air conditioning systems. More specifically, the invention pertains to those problems associated with the growth of mold and mildew on or around such systems.  
         [0003]     Mold and mildew growth in buildings is a serious problem. In particular, areas in close proximity to large bodies, and/or areas having high or consistent humidity, experience problems with the growth of mold and mildew in buildings. Condensation forms on surfaces, for example heating ventilation and/or air conditioning vents in buildings, which are below dew point temperature and are exposed to warm, humid air. These surfaces may contain dust or dirt, which is a food source for the growth mold and mildew.  
         [0004]     Common mold and mildew grows in temperatures ranging from about forty degrees to one hundred twenty degrees Fahrenheit, which includes the typical environment in which people live. When condensation forms on an interior surface of a building an environment is created for the growth of mold or mildew. Mold growth is typically eliminated by removal of fungi spores, which is performed by sophisticated HVAC filtration systems. However, a need exists for an inexpensive system and method for controlling the growth of mold and mildew.  
       SUMMARY OF THE INVENTION  
       [0005]     The invention for the system for preventing the growth of mold or mildew comprises an air diffusion device for covering an opening in a wall and/or at the end of a ventilation duct. The air diffusion device has at least one flange extending along at least a portion of a screen on the air diffusion device that covers the opening. At least one heating cable is affixed to the flange. When the heating cable is activated it raises the surface temperature of the flange and/or other parts of the air diffusion device above a dew point preventing condensation from forming on or near the air diffusion device. The term “dew point” is the temperature at which water vapor condenses onto a surface. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]      FIG. 1  is a sectional of an air diffusion device with a heating cable affixed thereto.  
         [0007]      FIG. 2  is a front elevational view of an air diffusion device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0008]     The system  10  is shown in the sectional view illustrated in  FIG. 1  and a front elevational view illustrated in  FIG. 2 . The system generally includes a heating cable  14  applied to a surface of an air diffusion device  11  that is used with a heating ventilation air conditioning system for a building. In the embodiment shown in  FIG. 1 , a vent is shown as including an opening  12  in a wall  13  and an air duct  15 , with an air diffusion device  11  mounted on the wall  13  over the opening  12 . The invention is not limited to an air diffusion device  11  mounted over an opening  12  in a wall, but may include an air diffusion device  11  that is mounted to an end of a duct that is for example not contained within a wall system.  
         [0009]     The air diffusion device  11  includes a screen  25  that covers the opening  12 . The term screen as used in this disclosure includes a covering that has openings through which air may pass, and may include a perforated metal covering. The embodiment shown in  FIGS. 1 and 2  the screen  25  includes a plurality of vanes  18  that cover opening  12 . The opening  12  is in fluid communication with the duct  15  for discharge of air into a room of the building.  
         [0010]     The air diffusion device  11  includes at least one flange that extends along at least a portion of a periphery of the screen  25  or vanes  18 . The air diffusion device  11  shown in  FIG. 1  includes a first flange  16  for fastening the air diffusion device  11  to the wall  13 . A second flange  17 , extending along a periphery of the vanes  18 , extends substantially perpendicular to a vertical disposition of the air diffusion device  11  and into the opening  12  of the wall  13  for alignment of the vanes  18  with respect to the opening  12  and duct  15 .  
         [0011]     In the embodiment shown in  FIG. 1 , the heating cable  14  is affixed to a back surface  23  of the first flange  16 . As shown in  FIG. 2 , the heating cable  14  preferably extends around a periphery of the vanes  18 . The heating cable  24  may also be applied to the second flange  17 . The heating cable  14  may be affixed to the flange  16  using known mechanical fasteners. For example, clips (not shown) may be operatively connected to the flanges  16  and  17  for attachment of the cable  14 . Alternatively, an adhesive may be applied to the cable or surface of the flanges  16  or  17  for attachment of the cable  14 . Depending on building code requirements and the cable  14  voltage, the cable may have to be contained within a conduit.  
         [0012]     The heating cable  14  may be a standard heating cable that is used for heating pipes and having a voltage rating ranging from about 120 volts to about 240 volts AC power. Such heating cables are available at known wholesale distributors and building/home supply stores, such as, W. W. Grainger, Johnstone Supply, Home Depot or Lowe&#39;s. Lower voltage heating cables, i.e., 24 volts AC or DC power, may be desirable because such a lower voltage cable typically is not required to be contained within a conduit.  
         [0013]     The heating cables  14  typically include electrical leads  20  that are connected to a junction box  21  mounted on an interior of the building wall  13 . A power cable  22  is connected from the power junction box  21  to a power source  24  for the activation of the heating cable  14 . The size of the heating cable  14  will depend, in part, on the size of the air diffusion device  11 , and the amount of surface area to be heated. The heating cable  14  selected should be such that it raises the surface temperature of the air diffusion device  11  to a temperature exceeding dew point temperature.  
         [0014]     The practice of the method includes the step of applying the heating cable  14  to the surface of the air diffusion device  11 . The heating cable  14  is then activated to elevate a temperature surface of the air diffusion device  11 . In doing so, the surface temperature of the diffuser is raised to a point exceeding dew point temperature. An additional benefit is that the air discharged from the HVAC system is further dried. When warm or hot, humid and wet air is allowed into the room the moisture in the room air will not condense on, at, or near the air diffusion device, which would otherwise create an environment for the growth of mildew or mold.  
         [0015]     While the invention has been described in what is presently considered to be a preferred embodiment, many variations and modifications will become apparent to those skilled in the art. Accordingly, it is intended that the invention not be limited to the specific illustrative embodiment, but be interpreted within the full spirit and scope of the appended claims.