Abstract:
A fabric air duct of an HVAC system includes a discharge air register with an air deflector that extends along the length of the duct. Rotating or twisting the deflector adjusts the volume and/or direction of the air being discharged from the register. Even though the deflector is disposed inside the duct, the deflector can be twisted or rotated by manipulating the exterior fabric wall of the duct.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The subject invention generally pertains to fabric air ducts and more specifically to a vent for such a duct.  
           [0003]    2. Description of Related Art  
           [0004]    HVAC systems (heating, ventilating and air conditioning systems) often include a network of sheet metal air ducts for conveying conditioned air through a building. The ductwork often includes several registers for discharging the air into certain rooms or areas within the building. To balance the distribution of airflow throughout the building, each register may include a damper for adjusting the amount or direction of airflow through individual registers. Currently, there is a wide assortment of registers and dampers that are readily available for use on ductwork made of sheet metal.  
           [0005]    Sheet metal, however, is not necessarily the best material for air ducts. In many applications, such as food-processing facilities, the ducts are preferably made of a fabric or other type of pliable, non-corrosive material. Fabric and other pliable materials are often preferred when cleanliness, even air dispersion, condensation control, or appearance is a significant concern.  
           [0006]    Unfortunately, conventional metal dampers and register are not readily incorporated into fabric ductwork. Metal hardware can be difficult to attach to fabric, the weight of the metal may pull and tear on fabric, and metal registers would most likely need to be removed before a fabric duct could be machined washed.  
           [0007]    Some adjustable registers, nonetheless, have been designed specifically for use with fabric air ducts. An example of such a register is disclosed in U.S. Pat. No. 6,280,320. In this example, the register includes an elongate member that can be slid lengthwise to adjust the volume of air discharged from the duct. Although effective for its intended purpose, the volume of air through the register is substantially uniform over its entire length, and the register cannot adjust the direction of airflow.  
           [0008]    To avoid creating an uncomfortable draft or to avoid discharging air directly against food products, in some cases it may be more desirable to redirect the airflow or to block off certain portions of it rather than to restrict the airflow along the entire length of the register. Thus, there is a need for providing fabric air ducts with a register that can change the volume and direction of airflow and perhaps do so at various locations along the length of the register.  
         SUMMARY OF THE INVENTION  
         [0009]    In some embodiments, a fabric air duct includes an air deflector for adjusting the direction or volume of discharge air.  
           [0010]    In some embodiments, an air deflector is mountable inside a fabric air duct and can be repositioned by manipulating the outer surface of the duct.  
           [0011]    In some embodiments, a fabric air duct includes an elongate air deflector that can be twisted to change the airflow at varying degrees along the length of the deflector.  
           [0012]    In some embodiments, a fabric air duct includes an elongate air deflector that has an oblong cross-sectional area.  
           [0013]    In some embodiments, a fabric air duct includes a pliable air permeable strip of material for holding an air deflector inside the duct.  
           [0014]    In some embodiments, the air permeable material is a fabric mesh that provides less airflow resistance than a plurality of holes in the fabric air duct.  
           [0015]    In some embodiments, a fabric air duct includes an internal fabric sheath that allows an elongate air deflector to be readily removable from within the duct. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a side view of an air duct assembly with a cutaway view showing an air deflector.  
         [0017]    [0017]FIG. 2 is a cross-sectional view taken along line  2 - 2  of FIG. 1.  
         [0018]    [0018]FIG. 3 is a cross-sectional end view showing the pliable wall of an air duct being manually manipulated to move an internally disposed air deflector.  
         [0019]    [0019]FIG. 4 is similar to FIG. 1 but showing the deflector in another position.  
         [0020]    [0020]FIG. 5 is a cross-sectional view taken along line  5 - 5  of FIG. 4.  
         [0021]    [0021]FIG. 6 is similar to FIG. 1 but showing the deflector in yet another position.  
         [0022]    [0022]FIG. 7 is a cross-sectional view taken along  7 - 7  of FIG. 6.  
         [0023]    [0023]FIG. 8 is similar to FIG. 1 but with two cutaway views showing two portions of a twisted deflector.  
         [0024]    [0024]FIG. 9 is a cross-sectional view taken along line  9 - 9  of FIG. 8.  
         [0025]    [0025]FIG. 10 is a cross-sectional view taken along line  10 - 10  of FIG. 8.  
         [0026]    [0026]FIG. 11 is similar to FIG. 1 but with two cutaway views showing two portions of another twisted deflector.  
         [0027]    [0027]FIG. 12 is a cross-sectional view taken along line  12 - 12  of FIG. 11.  
         [0028]    [0028]FIG. 13 is a cross-sectional view taken along line  13 - 13  of FIG. 11.  
         [0029]    [0029]FIG. 14 is similar to FIG. 1 but with another type of air deflector installed inside the duct.  
         [0030]    [0030]FIG. 15 is a side view of a helical air deflector.  
         [0031]    [0031]FIG. 16 is similar to FIG. 1 but showing another embodiment of an air duct assembly.  
         [0032]    [0032]FIG. 17 is a partial side view of a segmented air deflector.  
         [0033]    [0033]FIG. 17 a  is a cross-sectional view taken along line  17   a - 17   a  of FIG. 17.  
         [0034]    [0034]FIG. 17 b  is a cross-sectional view taken along line  17   b - 17   b  of FIG. 17.  
         [0035]    [0035]FIG. 17 c  is a cross-sectional view taken along line  17   c - 17   c  of FIG. 17.  
         [0036]    [0036]FIG. 17 d  is a cross-sectional view taken along line  17   d - 17   d  of FIG. 17 b.   
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0037]    An air duct assembly  10 , shown in FIGS. 1 and 2, comprises a tubular air duct  12  that has a pliable wall  14  made of fabric or some other type of pliable material. Duct  4  can be of any tubular cross-sectional shape including, but not limited to, round, semicircular, quarter-round, square, rectangular, triangular, etc. A source of pressurized air  16 , such as a blower, forces air  18  into duct  12 . To disperse the pressurized air into a room or other area of a building, the pliable wall  14  of duct  12  is air permeable in at least certain areas. The air permeability can be provided in various ways, including but not limited to making pliable wall  14  of a porous material or by perforating an otherwise impervious material.  
         [0038]    For the illustrated example, the permeability of wall  14  is provided by a matrix of holes or openings  20 . In some cases, the openings are about 0.188 inches in diameter and have a center-to-center spacing of about 0.625 inches. The openings may be evenly distributed over an area that is about two inches high and extending along a substantial length of duct  12 . However, various other hole sizes and distribution patterns are well within the scope of the invention.  
         [0039]    To allow adjustment of the volume and/or direction of the air discharging through openings  20 , duct  12  includes a movable air deflector  22 . Deflector  22  is preferably installed inside duct  12 ; however, it is also well within the scope of the invention to install deflector  12  on the exterior of the duct. In some cases, deflector  22  has an oblong cross-sectional area, as shown in FIG. 2, and may be of any length (e.g., one-foot, eight-feet, twenty-feet, or longer). In the example shown in FIG. 2, deflector  22  has a major thickness  24  and a minor thickness  26  with a plurality of holes  28  extending through the minor thickness  26 . In some embodiments, major thickness  24  is 1.75 inches, minor thickness  26  is about one inch, and holes  28  have a diameter of about 0.5 inches with a center-to-center spacing of about 0.75 inches. Holes  28  serve as nozzles that direct pressurized air  18  through openings  20 . FIGS. 1 and 2 show deflector  22  directing the airflow in a generally downward direction.  
         [0040]    To hold deflector  22  in place, an air permeable pliable strip  30  (e.g., fabric netting, fabric screen, perforated plastic, etc.) holds deflector  22  up against an inner surface  32  of wall  14 . Upper and lower edges of strip  30  can be sewn, bonded, or otherwise attached to inner surface  32  of wall  14 . In effect, surface  32  and strip  30  provide a sheath  34  through which deflector  22  can be installed while still allowing periodic removal of the deflector so that wall  14  of duct  12  can be machine-washed.  
         [0041]    To adjust the volume or direction of discharged air, the entire length of deflector  22  can be rotated or portions of its length can be twisted within sheath  34  by manually manipulating the exterior of wall  14 , as shown by a hand  36  in FIG. 3. Arrows  38  and  40  represent manually exerted pressure that rotates or twists deflector  22  as indicated by arrow  42 . To enable the twisting of just portions the deflector&#39;s length, deflector  22  may need to be sufficiently flexible about its longitudinal centerline  44 . This can be achieved by various combinations of deflector shape, size, and material. In some embodiments, deflector  22  is made of PVC.  
         [0042]    To direct the discharged air in a generally upward direction, deflector  22  can be rotated to the position shown in FIGS. 4 and 5.  
         [0043]    To stop or minimize the airflow through openings  20 , deflector  22  can be rotated to the position shown in FIGS. 6 and 7. In this position, deflector  22  obstructs most or all of openings  20 .  
         [0044]    Referring to FIGS. 8, 9 and  10 , deflector  22  can be twisted about itself to move a first portion  22   a  of deflector  22  to the position shown in FIG. 9 and to move a second portion  22   b  of deflector  22  to the position shown in FIG. 10. In this configuration, some of the discharge air is directed downward (FIG. 9) and some is directed upward (FIG. 10). Numerous other combinations include, but are not limited to, some areas with upward flow and other areas with no flow, some areas with horizontal flow and other areas with downward flow, some areas with horizontal flow and other areas with upward flow, etc. The number of discrete areas having their own particular direction or volume of flow is based on the deflector&#39;s length and rotational flexibility.  
         [0045]    In another embodiment, shown in FIGS. 11, 12, and  13 , a normally flat, thin deflector  46  is inserted between strip  30  and wall  14  of duct  12 ′. Deflector  46  can be twisted about itself with one portion  46   a  lying flat against surface  32  to block off flow through openings  20  and another portion  46   b  being positioned to direct the airflow in a generally horizontal or upward direction. Or the entire deflector can turned in the same direction to provide uniform airflow or no airflow across the entire length of the duct. Deflector  46  does not need any holes  28  since deflector  46  is sufficiently thin to allow air to pass by it when turned at an angle as shown in FIG. 13. Deflector  46  can be made of plastic, steel, or any other appropriate material.  
         [0046]    In a similar embodiment, shown in FIGS. 14 and 15, a relatively thin deflector  48  has a permanent helical twist. When inserted within sheath  34  (FIG. 2), deflector  48  disperses the discharge air  18  in various directions: upward, downward, and horizontal. The direction of airflow at various areas along the length of the duct is determined by the rotational position of deflector  48  within sheath  34 .  
         [0047]    In another embodiment, shown in FIGS. 16 and 17, an air duct assembly  10 ′ includes an air deflector  50  that is segmented, so individual segments (e.g.,  50   a ,  50   b ,  50   c , etc.) can be rotated independently of each other. This allows one segment to redirect the discharge airflow at certain areas along the length of duct assembly  10 ′while minimizing that segment&#39;s affect on other areas of the duct. Deflector  50  comprises at least two deflector segments (e.g.,  50   a ,  50   b ,  50   c , etc.) that can be installed end-to-end within a sheath  34 ′. Pins  52  inserted into axial cavities  54  can help align the series of segments, or the segments can simply abut one another without the use of pins  52 . To minimize the number of pieces for a given deflector, pins  52  can be an integral extension of one end of each segment, so each segment would have a male and female end that allow the segments to be interconnected.  
         [0048]    If it is desired to have some areas in a room provided with less air than others, an air duct assembly may have certain areas along its length that are void of openings  20 . Air duct assembly  10 ′, for example, has areas  56  and  58  where the airflow is completely blocked off. In this case, segment  50   a  may be adjacent to openings  20   a , and segment  50   c  may be adjacent to openings  20   c . Segments  50   a  and  50   c  can simply be spaced apart from each other with no segment by area  56  (i.e., omitting segment  50   b ), or segment  50   b  can be interposed between segments  50   a  and  50   c  as shown in FIG. 17. If segment  50   b  is used and is placed adjacent to area  56 , then segment  50   b  would only serve as a spacer between segments  50   a  and  50   b . Of course, if openings  20   a  and  20   c  extended continuously without areas  56  and  58  as shown in FIG. 1, then all of the segments  50   a ,  50   b , and  50   c  could be used to direct airflow.  
         [0049]    Although the invention is described with reference to a preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the claims that follow.