Abstract:
A revolving door deicer/dryer system including a floor grate having a bottom side and a heating system associated with the bottom side of the floor grate. The heating system includes at least one shaped plate and at least one heating element serpentinely routed on the at least one shaped plate.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the invention 
         [0002]    The present invention relates to a rotary door floor heating system, and, more particularly, to a rotary door floor deicing and drying system. 
         [0003]    2. Description of the Related Art 
         [0004]    Under floor heating systems date back thousands of years including Roman and Korean heating system where stone slabs are installed on an upper part of flues in a hypocaust connected with a fuel feeding port and a chimney. A burning fuel, such as wood or coal is burnt thereby heating the floor from the underneath side. The problem with this system is that a lot of thermal energy is drawn off by way of the fuel feeding hole and the chimney when a fire is not kindled therein. Some modern floor heating systems include the circulation of a heated thermal medium fluid through long, thin seamless pipes disposed beneath a floor. A floor heating system that involves the circulation of a thermal medium fluid has a portion of a floor that is heated to a higher temperature than a portion of the floor associated with the end of the circulation path. For example, the temperature of the heated thermal medium as it circulates gradually decreases in temperature causing the portion that is first heated to be heated to a higher temperature than the area of the floor associated with the end of the circulation path. 
         [0005]    Building entryways often have grate systems for the dissipation of water that is tracked in by pedestrian traffic. Grate systems often have a channel for the diverting of moisture to a drain that is located beneath the grid system. Grid systems are often located in an exterior environment, such as with a rotary door having a sector of the floor grid being exposed to the outer ambient environment. The temperature of the outer environment may be below freezing, which can result in a buildup of ice on the exposed exterior portion of the floor. Another problem with rotary doors is that moisture is tracked from the entrance sector to adjacent sectors, which can result in a transition from ice or snow to melted water. The problem with water on floor grates of rotary door systems is that the grate system is made of a resilient material, such as metal and the presence of ice and/or moisture thereon can cause the surface to have a reduced frictional characteristic. 
         [0006]    What is needed in the art is a simple to install system for the deicing and drying of entrance door floor grates. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a modular installation system for heating rotary door floor grates. 
         [0008]    The invention comprises, in one form thereof, a revolving door deicer/dryer system including a floor grate having a bottom side and a heating system associated with the bottom side of the floor grate. The heating system includes at least one shaped plate and at least one heating element serpentinely routed on the at least one shaped plate. 
         [0009]    An advantage of the present invention is that the heating system is inserted underneath a sector of a floor grate from a rotary door system. 
         [0010]    Another advantage of the present invention is that the presence of ice and/or moisture is sensed and controlled, and the drain is heated by heating elements that extend thereinto. 
         [0011]    Another advantage of the present invention is that power is supplied to the heated floor sector by way of existing plumbing that serves as a drain for the subfloor beneath the rotary door grate system. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0013]      FIG. 1  is a perspective view of a rotary door system including floor grates heated by an embodiment of the present invention; 
           [0014]      FIG. 2  is a top view of the rotary door system of  FIG. 1 , showing a cutaway with the heating system of the present invention being illustrated thereunder; 
           [0015]      FIG. 3  is an underneath view of a floor grate sector of  FIGS. 1 and 2  showing the modular heating elements installed thereon; 
           [0016]      FIG. 4  is an exploded view of a floor grate heating system of  FIGS. 1-3 ; 
           [0017]      FIG. 5  is a cross-sectional view of the heated floor grate of  FIGS. 1-4 ; 
           [0018]      FIG. 6  is an enlarged cross-sectional view of a portion of the floor grate heating system of  FIGS. 1-5 ; and 
           [0019]      FIG. 7  is a schematical representation of the floor grate heating system of  FIGS. 1-6 . 
       
    
    
       [0020]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    Referring now to the drawings, and more particularly to  FIGS. 1 and 2 , there is illustrated a rotary door system  10  including a rotary door  12 , an enclosure  14 , floor grates  16  and an ice melting/drying system  18 . Rotary door system  10  provides a quasi-air-lock system for entry into a building. A substantially cylindrical enclosure  14  extends a circumferential distance, that precludes a direct airway between the interior and the exterior of the building, as door  12  rotates. Door  12  rotates in a particular direction, normally counter-clockwise when viewed from above. A person enters an outer portion of rotary door system  10  and normally proceeds to the right causing door  12  to rotate counter-clockwise and allows the person to enter by way of the rotating sector of space in which the individual is temporarily enclosed. 
         [0022]    Now, additionally referring to  FIGS. 3-7 , floor grates  16  include channels  20 , drain holes  22  and support fins  24 . Floor grates  16  are generally shaped as shown in  FIGS. 3 and 4  to extend over approximately one quadrant of the floor so as to allow a single floor grate  16  to be lifted up for maintenance purposes, while door  12  is positioned to allow the removal of the appropriate sector. Channels  20  on a top surface of grate  16  allow for the flow of water that is melted to travel to drain holes  22  allowing the water to drain through the surface of floor grates  16  and for its eventual removal from the system. Support fins  24  extend from a bottom surface of floor grate  16  to provide rigidity for grates  16  and to contact with portions of subfloor  26 . Support fins  24  while providing rigidity for grates  16 , introduces obstacles, which the present invention works around in order to provide heat to floor grate  16 . Subfloor  26  additionally has a floor drain  28  for the removal of water that drains through floor grate  16 . 
         [0023]    Ice melting/drying system  18  includes plates  30  having slots  32  therein. System  18  additionally includes heater conductors  34 , tape  36 , heated leads  38 , an electrical connection  40 , conductors  42 , a sensor  44 , sensor conductors  46  and a controller  48 . Plates  30  have slots  32 , which accommodate support fins  28  of grates  16 . Slots  32  allow for plate  30  to be seated against a surface of the underneath side of grate  16  to allow the conduction of heat into grates  16 . In the example shown in  FIGS. 3 and 4  two plates  30  each having slots  32  are used to provide heat to one floor grate sector  16 . Heater conductors  34  are routed upon a surface of plate  30  in a serpentine manner and are covered with heating tape  36 , which may be in the form of a metallic adhesive tape that bonds well with plate  30 . At an end of the conduction paths of heater conductors  34 , heater conductors  34  extend away from plate  30  and be electrically connected at electrical connection  40 . The extension of heater conductors  34  is shown and identified as heated leads  38  that extend into drain  28 . This advantageously provides heat in drain  28  to prevent the accumulation of ice therein. At some point along heater leads  38  electrical connection  40  is utilized to connect heated conductors  34  and heated leads  38 , which are arranged in a serial electrical connection to power supplying conductors  42 . Conductors  42  extend back to controller  48 , which supplies power to heater conductors  34  and heated leads  38 . 
         [0024]    A sensor  44  detects the presence of moisture which may be liquid or frozen and provides information by way of sensor conductors  46  to controller  48 . While what is shown in  FIG. 7  is one sensor  44  it can be understood that each flooring grate  16  may include at least one sensor  44 . Information regarding the presence of moisture on grating  16  causes controller  48  to provide power to heating conductors  34  and heated leads  38 . 
         [0025]    Since floor grating  16  should provide a safe dry surface for pedestrians the mere melting of snow may be insufficient and a drying operation is needed to remove the moisture from grates  16 . Although it can be understood that sensor  44  may be a temperature sensor the mere heating of floor grate  16  when it is cold may not be necessary if moisture is not present. While the control system can be utilized to simply heat floor grating  16  based on the temperature thereof sensor  44  detects moisture on grates  16 . As shown in  FIG. 7 , conductors  42  and sensor conductors  46  are routed through existing plumbing fixtures, which provides two advantages. One advantage is that no other wire routing system is necessary. Another advantage is that heated leads  38  prevent a buildup of frozen water in drain pipe  28 . 
         [0026]    Often doors  12  are restrained to rotate in one direction, which advantageously allows the installation of ice melting/drying system  18  in a first grate  50 , which is located on an exterior side of door  12 . One adjacent sector grate  52  may additionally be heated in the event that moisture may be carried from grate  50  onto grate  52 . Advantageously the present invention allows the installer to decide how many grates  16  the present invention is applied to based on the likely exposure of rotary door system  10  to moisture. 
         [0027]    In the event that door system  10  is in a busy portion of a building the present invention allows for the easy removal/installation of melting/drying system  18  to and from grates  16 . 
         [0028]    While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.