Abstract:
An air curtain resistant heating system including multiple heating coils integrated within blower fan cages. The multiple heating coils defining an inflow venture air pattern for increased heat transfer and fan cage internal flow vortex dependent on coil flow conveyance. Coil orientation placement assures limited impact to effect blower pressure and therefore minimizes loss of air performance parameters. Multiple phase electrical supply for multiple paired heating coils positioned in corresponding multiple blower fan units in an air curtain assembly.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to the field of air curtains used to create an airflow defined barrier in openings in buildings between interior and exterior or different conditioned spaces within the building for reduced energy use by environmental retention therebetween. 
     2. Description of Prior Art 
     Prior art devices of this type have been directed towards air curtains and associated air blower assemblies that include airstream conditioning such as heating. Typically, air curtains are limited to ambient air recirculation with the inclusion of heaters to condition the airflow as it leaves the blower through a directional outlet nozzle to form a laminar airflow barrier between openings. All known air curtain configurations condition the airflow pre or post blower, see for example U.S. Pat. No. 5,984,649. 
     Other heated air blower units have been developed for a variety of air heating applications with associated electric resistant coils, see for example U.S. Pat. No. 4,988,847 for defogging a bathroom mirror and well known portable electric heaters used for auxiliary point of use heating too numerous to list. 
     SUMMARY OF THE INVENTION 
     An air curtain unit with multiple blower fans having integrated heating coils positioned within intake air stream venturies defined by their interior of the impellor fan cage as such the heating coils conform to and define a venture airflow characteristic by integrated coil dimension augmentation for maximum heat transfer from respective opposing heat coil placements with minimal air outflow impact. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front top elevational view of the air curtain heating system of the invention with portions cut away. 
         FIG. 2  is an enlarged side elevational view with portions cut away. 
         FIG. 3  is an enlarged partial side elevational view with portions cut away of an outer heating coil assembly positioned within the fan cage. 
         FIG. 4  is an enlarged partial end elevational view thereof. 
         FIG. 5  is a graphic illustration of the three phase power supply circuit associated with the energization of the multiple heating coil assemblies therewith. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1  of the drawings, an air curtain assembly  10  of the invention can be seen having a generally rectangular support pan  11  with a pair of air blower assemblies  12  and  13  positioned thereon in opposing aligned relation to one another. The air blower assemblies  12  and  13  are identical with an interconnected drive electric motor assembly  14  mounted therebetween for bi-directional driving as will be explained in detail hereinafter. 
     The electric motor assembly  14  has an upstanding motor support frame mount  15  with an electric drive motor  16  mounted thereon. The drive motor  16  has a pair of oppositely disposed extending power drive shafts  17  and  18  with respective associated bearing assemblies  17 A and  18 A and a power is controller  19  as is well known and understood within the art. The power controller  19  is in electrical communication with a power supply motor control circuit C well known and understood within in the art in such industrial applications. 
     As noted, each of the blower assemblies  12  and  13  are identical having a blower housing cylindrical casings  20  and  21  with integrated rectangular extending nozzle outlets  20 A and  21 A formed thereon secured to the support pan  11  as best seen in  FIG. 2  of the drawings. Each air blower has a fan cage  22  supported in rotational relationship therewithin on corresponding respective free ends of the drive shafts  17  and  18  by a central impellor mounting disk  23 . Each fan cage  22  comprises a plurality of cross-sectionally contoured impellor blades  24  which are supported, as noted, by the central mounting disk  23  registering annularly thereabout and respective oppositely disposed annular cage end impellor support rings  25  for engagement and support of the corresponding parallel annularly spaced multiple contoured impellor blades  24  fabricated by typical manufacturing methods well known within the art. 
     Outer end multiple heating coil mounting brackets  26 , best seen in  FIGS. 1 ,  2  and  3  of the drawings are fitted within respective open ends  22 A of the fan cages  22 . 
     The mounting brackets  26  support multiple annular spaced coil engagement elements  27 , each bracket having multiple half arcuate coil receiving notches  26 A,  26 B and  26 C therewithin. The mounting brackets  26  extend from outside the impellor&#39;s fan cage  22  inwardly holding the assistant heating coils  27 A,  27 B and  27 C of different annular dimensions. 
     In this example, the coils  27 B and  27 C are of identical dimension with coil  27 A of an increased diameter dimension so as to form a venturi shaped air intake flow V (illustrated by flow arrows) feeding into and within the fan cages  22  during operational rotation by the drive shafts  17  and  18  as hereinbefore described. 
     Referring now to  FIG. 3  of the drawings, the “inner” inside end mounting coil configuration can be seen on the blower assembly  12  wherein modified coil mounting brackets  28  are positioned in spaced annular relation to mount respective split heating coils  29 A and  29 B inside the respective cage ends  22 B facing the aforedescribed drive motor  16 . The heating coils  29 A and  29 B are split with a gap at  30  allowing insertion and removal around the respective drive shaft extensions  17  and  18  passing through the center of the coils to the central mounting disks  23  on the drive shaft&#39;s respective free ends and the electric motor  16 , as noted. Given the reduced coil diameter of the inside end coils  29 A and  29 B so positioned within the respective cage ends  22 B, a venturi shaped inflow airstream V is also created therewithin with the associated enhanced efficiency and economy of co-laminar airflow over the coils for maximum heat transfer with the cage ends  22 B. 
     Referring now to  FIG. 5  of the drawings, an electrical supply coil energizing circuit  31  is graphically illustrated for distributing measured equal power supply to the multiple heating coils defined for clarity as outside coil assemblies  31  and  34  and corresponding inner heating coil assemblies  32  and  33  shown graphically. As noted, each of the heating coil assemblies  31 ,  32 ,  33  and  34  have multiple coils hereinbefore described as outside coil element pairs  27 A,  27 B,  27 C and inside coil element pairs  29 A and  29 B within respective coil assemblies  31  and  34  and  32  and  33  noted. 
     It will be seen when a three phase commercial power source is used defined in the graphic electrical supply circuit  31  as L 1 , L 2  and L 3  each of, in this example, 208 volts the outside coil pair assemblies  31  and  34  are supplied by L 2  at approximately 4.66 kw each and the inside coil pair coil assemblies  32  and  33  are supplied in parallel at 2.33 kw each thus defining an equal power supply of 4.66 kw each coil configuration as will be understood by those skilled in the art. 
     It will be evident that the hereinbefore described integrated inner venturi heaters for air curtains provides a unique combination of integrated fan inclusively positioned airflow determinant heating coil assemblies in the respective ends of corresponding impellor fan cages of blower assembly used within an air curtain configuration to impart a modified venturi air intake effect over the respective heating coil surfaces for increased efficiency and enhanced heat transfer with the utilization of a unique three power phase supply electrical energy distribution into corresponding four coil assembly use of equal power intake available only in the configuration set forth in the above referred to description and embodiment. 
     It will thus be evident that a new and novel air curtain venturi integrated heater configurations have been illustrated and described and it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.