Patent Publication Number: US-7895771-B2

Title: Clothes dryer with thermal insulation pad

Description:
FIELD OF THE INVENTION 
     The present invention relates to a clothes dryer having a thermal insulation pad strategically placed in the dryer cabinet relative to the blower fan housing to reduce the risk of fire starting in this area of the dryer cabinet or spreading through this area between the dryer drum and the lower portion of the dryer cabinet. 
     BACKGROUND OF THE INVENTION 
     Clothes dryers for domestic use typically comprise a rotating drum in which clothes are tumbled as warm air moves through the drum. Airflow through the drum is induced by a centrifugal fan, or blower fan, located in an exhaust duct that has an opening facing into the front open end of the dryer drum. This opening is typically covered by a grill. The exhaust duct has a lint filter for trapping lint particles from continuing to flow through the exhaust duct. The blower fan is in airflow communication with this exhaust duct to draw air from the duct through the fan and out through a tangential duct which airflow then turns and goes through an exhaust duct pipe exiting to the rear of the dryer. The blower fan is mounted generally within a blower wheel housing and the fan is driven by a motor. The blower fan is typically located below the dryer drum to one side thereof so as to optimize the use of space within the dryer cabinet. 
     In recent tests to determine fire hazards within the dryer, cheese cloth has been placed in a confined space between the outside wall of the blower wheel housing and the closest adjacent side wall panel of the dryer cabinet. The cheese cloth represents either dust or lint particles which over time might collect in this confined space. During the testing, the operation of the blower fan drawing heated air out of the dryer has a tendency to warm the blower wheel housing causing the cheese cloth placed in this location during the testing to catch fire. Moreover, this has resulted in additional cheese cloth placed outside the dryer side wall adjacent the location of the blower wheel housing to catch fire when the cheese cloth within the dryer catches fire due to heat being conducted by and through the cabinet side wall. Also, the confined space may act as a pathway along which fire may spread between the dryer drum and lower portion of the dryer cabinet. Accordingly, there is a need to reduce the risk of fire starting in the confined area between the blower wheel housing and the side wall of the dryer cabinet closest to the housing and to reduce the risk of fire spreading between the dryer drum and lower portion of the dryer cabinet via the confined space. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention relates to a clothes dryer having a thermal insulation pad that is placed within a confined space between the blower wheel housing and the dryer cabinet side wall closest thereto. By placing a thermal insulation pad strategically in this location, the pad fills up much of, if not all of, the volume of the confined space between the blower housing and the side wall of the cabinet closest thereto. Hence, the thermal insulation pad prevents the accumulation of combustible dust or lint over time in the confined space while also preventing the flow of oxygen to the confined space. Accordingly, the thermal insulation pad reduces the risk of a fire starting in the confined area of the dryer cabinet between the blower wheel housing and the adjacent side wall of the cabinet. Also, the thermal insulation pad acts as a barrier reducing the risk of fire, should one occur in the dryer drum or lower portion of the dryer cabinet, from spreading via the confined space between the dryer drum and lower portion of the dryer cabinet. 
     It should be understood that the thermal insulation pad utilized by the present invention may comprise any pad of material that has for example a plastic or woven material outer jacket with a fibrous filled material. The material does not have to resist high levels of heat because the blower fan housing does not rise to overly high temperatures during operation. Hence the thermal insulation pad only requires limited thermal insulation capabilities. In practice it has been found that padded material suitable for sound proofing works in this environment. Accordingly another advantage associated with a thermal insulation pad is that it provides some noise buffering or dampening by its placement in the confined space. 
     It should be further understood that the thickness of the thermal insulation pad may be chosen to be slightly greater than the width of the confined space where the blower wheel housing is closest to the closer one of the side walls whereby the thermal insulation pad is press fit into position. The width of the thermal insulation pad may be longer than the depth of the blower housing such that the thermal insulation pad extends beyond the blower housing and partially back rearwardly of the dryer adjacent the motor for driving the centrifugal fan of the blower housing. The length of the thermal insulation pad may be chosen to be greater than that of the height of the blower housing such that the thermal insulation pad may be bent to follow the rounded contour of the blower wheel and may be held in place by simple means of suitable tape, such as, for example, duct tape adhering to both the thermal insulation pad and the blower wheel housing. 
     In accordance with one embodiment of the present invention, a clothes dryer comprises a cabinet having a pair of side walls, a drum mounted for rotation in the cabinet, and a blower wheel housing supporting a blower fan for moving air through the drum. The blower wheel housing is mounted in the cabinet generally below the dryer drum and to one side thereof, and is closer to one of the pair of side walls. A confined space is located between the blower wheel housing and the closer one of the side walls. The clothes dryer further comprises a thermal insulation pad positioned in the confined space between the blower wheel housing and the closer one of the side walls. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more thorough understanding of the nature and objects of the present invention reference may be had, by way of example, to the accompanying diagrammatic drawings in which: 
         FIG. 1  is a perspective view of an exemplary clothes dryer that may benefit from the present invention; 
         FIG. 2  is a side sectional view of an exemplary clothes dryer that may benefit from the present invention wherein a front lower portion of the drum has been broken away in the illustration; 
         FIG. 3  is an enlarged perspective view of the exemplary clothes dryer showing the thermal insulation pad located in the dryer cabinet partially surrounding the blower wheel housing; and, 
         FIG. 4  is a front sectional view showing the location of the thermal insulation pad relative to the blower housing and side wall of the cabinet. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 and 2  show perspective and side sectional views of an exemplary clothes dryer  10  that may benefit from the present invention. The clothes dryer  10  includes a cabinet or a main housing  12  having a front wall  14 , a rear wall  16 , a pair of side walls  18  and  20  spaced apart from each other by the front and rear walls, a floor  21  and a top cover  24 . Within the housing  12  is a drum or container  26  mounted for rotation around a substantially horizontal axis. A motor  44  rotates the drum  26  about the horizontal axis through, for example, a pulley  40  and a belt  42 . The drum  26  is generally cylindrical in shape, has an outer cylindrical wall  28 , and has an open end  27  that typically comprises a metal ring  29  attached by welding to the drum  26  for reducing the diameter of the opening of the drum  26  to match a front bulkhead wall or front bearing  30 . The bearing  30  further defines an opening  32  into the drum  26 . Clothing articles and other fabrics are loaded into the drum  26  through the opening  32 . A plurality of tumbling ribs (not shown) are provided within the drum  26  to lift the articles and then allow them to tumble back to the bottom of the drum as the drum rotates. The drum  26  includes a rear wall  34  rotatably supported within the main housing  12  by bearing  35 . The rear wall  34  includes a plurality of holes (not shown) that receive hot air that has been heated by a heater such as electrical heating elements (not shown) in the heater housing  22 . The heater housing  22  receives ambient air via an inlet  36 . Although the exemplary clothes dryer  10  shown in  FIG. 1  is an electric dryer, it could just as well be a gas dryer having a gas burner. 
     Heated air is drawn from the drum  26  by a blower fan  48  which is also driven by a second motor  49  in the embodiment shown. In an alternative embodiment, motor  44  could be used to drive blower fan  48 . The air passes through a grill  45  and screen filter  46 . Grill  45  keeps clothing articles tumbling in the drum  26  from contacting the filter  46  and touching the lint trapped by the filter  46  within the trap duct  50 . As the air passes through the screen filter  46 , it flows through lower duct portion  51  and is drawn by blower wheel  48  attached to motor  49  out of the clothes dryer through an exhaust duct  52 . In this embodiment, the drum  26  is in air flow communication with the trap duct  50  whose lower duct portion  51  has an outlet that is in air flow communication with the blower wheel  48  and the exhaust duct  52 . The exhaust duct  52  passes through the rear panel  16  and is usually connected to suitable venting (not shown) that provides an exhaust path for the dryer heated air to leave the room where the dryer  10  is located. 
     After the clothing articles have been dried, they may be removed from the drum  26  via the opening  32 . Opening  32  is shown closed by a window or port-hole like door  60 . Door  60  has a handle  62  for pivotally opening the door about hinge  64 . 
     The dryer  10  is shown to have a control panel  54  with touch and or dial controls  56  that permit the user to control operation of dryer  10 . 
     Referring to  FIGS. 2 ,  3  and  4 , there is shown a thermal insulation pad  74  positioned to partially surround the outer circumference of the blower wheel housing  70 . The thermal insulation pad  74  is located in confined space  76  between the side wall  18  and the cylindrical end wall  73  of the blower wheel housing  70 . It should be noted from the drawings that the side wall  18  is the closer of side walls  18  and  20  to the blower wheel housing  70 . 
     As best seen in  FIG. 4 , the thermal insulation pad  74  is press fit into a confined space  76  between side wall  18  and the cylindrical end wall  73  of the blower wheel housing  70 . The thermal pad  74  has a thickness  75  which is greater than the distance  71  between the side wall  18  and the blower wheel housing  70 . Thermal insulation pad  74  is bent to follow the contour of the end wall  73  and a piece of duct tape  78  is used to secure the thermal insulation pad  74  relative to the blower wheel housing  70 . The blower wheel has a width  80  (see  FIG. 3 ) which is greater than the depth  82  of the blower wheel housing  70  such that the pad  74  extends rearwardly of the dryer cabinet and partially overlaps a portion of the motor  49  used to drive the blower fan  48  found in the blower wheel housing  70 . As shown in  FIG. 3 , the length of the thermal insulation pad  74  between its lower end  84  and its upper bent end  86  is greater than the height  88  of the blower wheel housing so as to allow the thermal insulation pad to be partially bent and overlap an upper portion of the cylindrical end wall  73  of the blower wheel housing  70 . It should be understood that in an alternative embodiment the length and/or width of the thermal pad  74  maybe chosen to be different so long as its overall dimensions reduce the risk of fire starting in the confined space  76 . 
     The thermal insulation pad  74  preferably comprises a fiberglass woven material located within either a woven material jacket or a plastic enclosure such that the pad  74  fills much of the volume of the confined space  76  between the blower wheel housing  70  and the adjacent side wall panel  18 . This prevents the accumulation of lint or dust over a period of time and also does not allow oxygen into this area thereby precluding the starting of a fire in this confined space  76  of the cabinet  12 . It should be understood that any suitable insulation material may be used and that the insulation material need not necessarily be flexible to bend around the cylindrical end wall  71  of the blower wheel housing  70 . In an alternative embodiment it is envisaged that a stiffer material may be utilized which extends vertically up between the blower wheel housing and the side panel  18 . Furthermore, the thermal insulation provided by the thermal insulation pad  74  acts as sound proofing insulation. Accordingly a secondary advantage associated with the use of a thermal insulation pad is it provides a sound buffer or dampener for noise associated with the blower wheel housing  70  adjacent the side wall  18 . 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the scope of the present invention as disclosed herein.