Abstract:
The improved dryer flexible exhaust ducting of the present invention is comprised of a flexible exhaust ducting with a nonconductive, high temperature polymer treated coupling member. The dielectric dryer coupling member prevents the travelling of electrical current from an inadvertently energized dryer chassis to the attached flexible ducting and thus prevents the ducting from overheating or melting from the electrical current or igniting flammable materials nearby or contained within the ducting.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application is a continuation in part of U.S. application Ser. No. 15/208,317 filed Jul. 12, 2016 which claims the benefit of and priority to a U.S. Provisional Patent Application No. 62/191,899 filed Jul. 13, 2015, the technical disclosures of which are incorporated by reference. This application claims the benefit of and priority to a U.S. Provisional Patent Application No. 62/371,717 filed Aug. 6, 2017, the technical disclosures of which are incorporated by reference. 
     
    
     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
       [0003]    The present invention relates generally to consumer and commercial appliances, and more particularly to consumer and commercial clothes dryers. This invention relates to clothes dryers having an improved output exhaust duct. 
       2. Description of Related Art 
       [0004]    Clothes dryers are a leading cause of residential fires in the United States. In 2010, clothes dryers and washing machines accounted for 4.5% of all reported home structure fires, 1.9% of associated civilian deaths, 2.8% of associated civilian injuries, and 3.1% of associated direct property damage. Clothes dryers accounted for 92% of these fires; washing machines 4%, and washer and dryer combinations accounted for 4%. The risk of fire is roughly equal for gas and electric dryers. 
         [0005]    From 2006-2010, the National Fire Protection Association NFPA reported a yearly average of over 15 thousand dryer fires in the United States per year, resulting in a yearly average of 29 deaths, 402 injuries, and approximately $192 million in direct property damage. The leading cause of home clothes dryer and washer fires was failure to clean 32%, followed by unclassified mechanical failure or malfunction 22%. Eight percent were caused by some type of electrical failure or malfunction. Out of these fires, the leading item first ignited in a clothes dryer fire was dust, fiber, or lint, causing 29% of the fires and 85% of the deaths. 
         [0006]    Many fires are caused each year by ignition of the flexible exhaust ducting that carries lint and exhaust air from the clothes dryer exhaust outlet to a vent system that is part of the residence. A standard flexible exhaust ducting is comprised of thin, conductive material such as aluminum or a nonconductive material such as vinyl. In flexible exhaust ducting made of nonconductive material, the walls of the ducting typically contain a conductive steel helical spring, in order to retain the tubular shape of the ducting and prevent collapse. The present mode of clothes dryer construction, gas or electric, relies on ridged sheet metal for the output exhaust duct on the dryer. Typically, the exhaust duct (which is part of factory construction and constructed of rigid sheet metal) is conductive. Similarly, the external dryer vent built into residences is typically constructed of conductive metal. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is a high temperature polymer coupling member to the flexible exhaust ducting for connecting the flexible exhaust ducting to the dryer exhaust duct and/or the external exhaust vent. This dielectric coupling member prevents any potential electrical current from being conducted through the flexible exhaust ducting. Additionally, this dielectric coupling member can prevent arcing between the flexible exhaust ducting and the dryer chassis, dryer exhaust duct, or the external exhaust duct in the wall. Ridges and external shoulders encircling the coupling member create additional barriers to prevent arcing. For purposes of this patent, a high temperature polymer is defined as one that in the intended usage does not suffer from chemical or mechanical changes that would make it unsuitable for its intended use. The exact temperature characteristics and composition of the polymer may well vary among different designs of clothes dryers. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    A more complete understanding of the apparatus of the present invention may be had by reference to the following detailed description when taken in conjunction with the accompanying drawings, wherein: 
           [0009]      FIG. 1  is an elevation view of the rear of a standard electric or gas dryer; 
           [0010]      FIG. 2  is a side view of a standard electric or gas dryer; 
           [0011]      FIG. 3  is a side view of an embodiment of the coupling member. 
           [0012]      FIG. 4  is a side view of an embodiment of the dielectric flexible exhaust ducting; 
           [0013]      FIG. 5  is a side view of a dryer exhaust system with an embodiment of the dielectric flexible exhaust ducting; 
           [0014]      FIG. 6  is a cross section view of line  6 - 6  in  FIG. 5  showing the coupling member of the dielectric flexible exhaust ducting connected to the exhaust duct. 
           [0015]      FIG. 7  is a cross section view of another embodiment of a coupling member of the dielectric flexible exhaust ducting connected to the exhaust duct. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIGS. 1 and 2  depict the back and side views, respectively, of a standard clothes dryer. The rear chassis  10  of the dryer is typically made of conventional sheet metal. The dryer exhaust duct  14  protrudes from the rear chassis  10  of the dryer. The dryer exhaust duct  14  is typically a tubular structure having an outer surface  16  and. an outlet  18 . The dryer exhaust duct  14  is typically crafted of the same conventional sheet metal as the rear chassis  10  of the dryer itself. 
         [0017]    Referring to  FIGS. 3, 4 and 6 , the flexible exhaust ducting  30  comprises a coupling member  40  and ducting member  50 . The coupling member  40  further comprises a generally tubular first sleeve  41  having an inner surface  42  and outer surface  43  connected to a generally tubular second sleeve  45  having an inner surface  46  and outer surface  47 . The inner diameter of the first sleeve  41  is greater than the outer diameter of the dryer exhaust duct  14  and the inner diameter of the second sleeve  45 . The second sleeve  45  is positioned within the first sleeve  41  such that a portion of the second sleeve&#39;s  45  outer surface  47  is in contact with a portion of the first sleeve&#39;s  41  inner surface  42 . An internal shoulder  44  is positioned between the first sleeve&#39;s  41  inner surface  42  and the second sleeve&#39;s  45  inner surface  46 . The outer diameter of the first sleeve  41  is greater than the outer diameter of the second sleeve  45  creating an external shoulder  48 . 
         [0018]    In a preferred embodiment, the first sleeve  41  and second sleeve  45  are integrally constructed as one piece. In another embodiment, the second sleeve  45  may be attached to the first sleeve  41  by adhesive or frictional means. The coupling member  40  is constructed of a high temperature polymer. In another embodiment, the inner surfaces  42 ,  46  of the coupling member  40  are coated with a high temperature polymer. In both embodiments, the coupling member  40  is dielectric. 
         [0019]    Referring to  FIGS. 4 and 6 , the ducting member  50  is generally tubular in shape having an open first end  51 , sidewall  52 , and an open second end  53 . The inner diameter of the ducting member  50  generally corresponds to the outer diameter of the second sleeve  45  such that the first end  51  of the ducting member  50  may slide over the outside surface  47  of the second sleeve  45 . The inner surface  54  of the ducting member  50  may be frictionally engaged with the outside surface  47  of the second sleeve  45 . The ducting member  50  abuts the external shoulder  48 . 
         [0020]    Alternatively, or in addition to, a mechanical device, such as a clamp, may be used to secure a portion of the second sleeve  45  within ducting member  50 . The ducting member  50  may be constructed of traditional ducting material such as a thin, conductive material such as aluminum or a nonconductive material such as vinyl, with a steel helical spring to maintain the tubular shape. In another embodiment, the coupling member  40  and the ducting member  50  are integral. 
         [0021]    Referring to  FIG. 6 , the coupling member  40  is fitted to the dryer such that the dryer exhaust duct  14  is positioned within the first sleeve  41  of the coupling member  40 . The inner diameter of the first sleeve  41  generally corresponds to the outer diameter of the dryer exhaust duct  14  such that friction secures the coupling member  40  to the dryer exhaust duct  14 . The coupling member  40  may be positioned such that it abuts the rear chassis  10  of the dryer but it is not required. The dryer exhaust duct  14  is positioned within the first sleeve  41  such that it abuts the internal shoulder  44 . The internal shoulder  44  prevents the dryer exhaust duct  14  from being positioned with the second sleeve  45 . The external shoulder  48  prevents the first end  51  of the ducting member  50  from contacting the dryer exhaust vent  14  or the rear chassis  10  of the dryer. 
         [0022]    The inner diameter of the dryer exhaust duct  14  generally corresponds to the inner diameter of the second sleeve  45  to prevent any restriction of exhaust flow. 
         [0023]    The outer diameter of the dryer exhaust duct  14  generally corresponds to the outer diameter of the second sleeve  45 . This permits a traditional ducting member  50  to be positioned around the second sleeve  45  of the coupling member  40 . 
         [0024]      FIG. 4  depicts an overall dryer exhaust system  60 . The dryer exhaust system comprises a dryer exhaust duct  14 , flexible exhaust ducting  30 , and an external exhaust duct  26  built into the wall  21  of a residence. Dryer lint  24  is also shown in the interior of the ducting member  50 . The coupling member  40  is positioned in such a manner that the conductive dryer exhaust duct  14  is not in contact with the conductive ducting member  50 . The construction of the coupling member  40  further prevents the potential for arcing. A traditional dryer, with a traditional flexible exhaust duct may be fitted with the coupling member to prevent current flow and arcing. Alternatively, an integral coupling member and ducting member may be utilized. 
         [0025]    Another embodiment is disclosed in  FIG. 7 . The flexible exhaust ducting  130  comprises a coupling member  140  and ducting member  150 . The coupling member  140  further comprises a generally tubular first section  141  connected to a generally tubular ridged second section  145 . The inner diameter of the first section  141  is greater than the outer diameter of the dryer exhaust duct  14 . An external shoulder  148  encircles the first section  141  approximately at the junction where the first section  141  and second section  145  join. Multiple ridges  149  may encircle the second section  145 . The ducting member  150  connects to the second section  145 . The coupling member  140  is fitted to the dryer such that the dryer exhaust duct  14  is positioned within the coupling member only and preferably within the first section  141 . The inner diameter of the first section  141  generally corresponds to the outer diameter of the dryer exhaust duct  14  such that friction secures the coupling member  140  to the dryer exhaust duct  14 . The coupling member  140  is constructed of a high temperature polymer. In another embodiment, the inner surfaces of the coupling member  140  are coated with a high temperature polymer. In both embodiments, the coupling member  140  is dielectric. 
         [0026]    Although the invention hereof has been described by way of a preferred embodiment, it will be evident that other adaptations and modifications can be employed without departing from the spirit and scope thereof. The terms and expressions employed herein have been used as terms of description and not of limitation; and thus, there is no intent of excluding equivalents, but on the contrary it is intended to cover any and all equivalents that may be employed without departing from the spirit and scope of the invention.