Patent Publication Number: US-6902287-B2

Title: Environmentally controlled appliance enclosure

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is directed to an appliance enclosure. More particularly, the invention concerns an appliance enclosure having a heater assembly that maintains a uniform temperature within the enclosure. 
   2. Reference to Related Art 
   Appliances such as emergency horns and strobe lights and the covers for those appliances are well known in the art. For example, the STI-1210 Series horn and strobe enclosures manufactured by Safety Technology, Inc. of Waterford, Mich., are known to include a spacer that may be mounted on a wall or similar surface and a transparent plastic cover that is secured to the spacer. A gasket may be provided in a joint between the spacer and cover to provide a waterproof seal. 
   Another commercially available product is the FARADAY® Model 2705 weatherproof strobe. This device uses a waterproof backbox for waterproof applications. 
   U.S. Pat. No. 4,320,949 is directed to a weatherized housing assembly for a camera. The weatherized housing includes a unitary plastic molded opaque housing that is generally shaped in the form of a frusto-conical inverted cup. A camera is positioned in the housing and a cover or dome is secured to the housing to enclose the camera. A fan is secured to an opening in the housing. Furthermore, a pair of electrical resistance heaters is positioned within the housing. If the temperature in the housing becomes too high, the fan is activated and circulates the air within the housing. If the temperature within the housing approaches freezing, a thermostatic switch in the housing is closed to energize the heaters to heat the air within the housing. Finally, a lamp can be provided on the exterior of the housing. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to an environmentally controlled appliance enclosure. The enclosure includes an enclosed spacer and a heater assembly positioned within the spacer. A heater unit(s) and fan are secured to the heater assembly. An appliance, such as a strobe light, is secured to an appliance mounting plate that is affixed to the heater assembly. Finally, a transparent plastic cover is secured to the spacer to thereby enclose the appliance. Once sealed, the heater unit(s) and fan of the heater assembly operate to maintain a uniform temperature within the enclosure. 
   Particularly preferred applications for the present invention include, but are not limited to, refrigerators, freezers, meat packaging plants, arctic environments, ocean rigs, slaughterhouses, etc. The enclosure of the present invention will also advantageously prevent build up of snow or the entry of moisture in wash-down areas to assure that the appliance (particularly strobes) remains clearly visible. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention will be had upon reference to the attached drawings wherein like reference numerals refer to like parts throughout and wherein: 
       FIG. 1 , is a perspective view of an environmentally controlled appliance (with attached appliance) constructed in accordance with a preferred embodiment of the present invention; 
       FIG. 2 , is an exploded perspective view of enclosure of in  FIG. 1 ; 
       FIG. 3 , is a perspective view of the heater assembly of the enclosure of in  FIG. 1 ; and 
       FIG. 4 , is a schematic view of the high and low voltage circuits for the enclosure of FIG.  1 . 
   

   DETAILED DESCRIPTION 
   Referring now to  FIGS. 1 and 2 , there is shown an environmentally controlled appliance enclosure  10  constructed in accordance with the present invention. Preferably, the enclosure  10  includes a spacer or “backbox”  12 , a heater assembly  14  positioned within the spacer  12 , a heater unit(s)  16  and a fan  18  that are each secured to the heater assembly  14 , an appliance mounting plate  20  that is secured to the heater assembly  14  and spacer  12  for use in mounting an appliance  100  and a cover  22  that is secured to the spacer  12 . 
   Still referring to  FIGS. 1 and 2 , and as best shown in  FIG. 2 , the spacer  12  is an enclosed spacer having a circular base  24  and a wall  26  that extends from the base  24 . The space  12  is preferably constructed of a polycarbonate material. However, it will be appreciated that other materials having the requisite characteristics of formability and strength, including composites, plastics, metals, alloys, etc. may also be used in the construction of the spacer  12 . The circular base  24  and wall  26  of the spacer  12  each have a preferred thickness in the range of 0.1-0.3 inches. In a particularly preferred embodiment, the circular base  24  has a thickness of 0.125 inches and the wall  26  has a thickness of 0.2 inches. 
   Referring now to  FIG. 2 , a pair of apertures  28 ,  30  are defined in the wall  26  in an opposed relationship to each other. The apertures  28 ,  30  permit a user to secure conduit connectors  102  for separate high (through aperture  30 ) and low (through aperture  28 ) voltage lines (not show) to the enclosure  10 . The conduit connectors  102  preferably include a high  104  and low  106  voltage sealing hub, a pair of rain tight hubs  108  and a pair of nibbles  110  for securing the sealing hubs  104 ,  106  to the rain tight hubs  108 . 
   Still referring to  FIG. 2 , a plurality of internally threaded spacer mounts  32  are provided along the exterior surface  34  of the wall  26  of the spacer  12 , proximate the circular base  24  for use in fixing the spacer  12  to a wall (not shown) or similar surface through the use screws (not shown) or the like. Likewise, a plurality of internally threaded cover mounts  36  are positioned along the exterior surface  34  of the wall  26  of the spacer  12  and, as discussed below, are used for securing the cover  22  to the spacer  12 . Finally, a plurality of internally threaded assembly mounts  38  are positioned along an interior surface  40  of the wall  26  of the spacer  12  for use in securing the heater assembly  14  and the appliance mounting plate  20  to the spacer  12 . 
   Referring now to  FIGS. 2 and 3 , the heater assembly  14  is positioned within the space  12  on the circular base  24 . As best shown in  FIG. 3 , the heater assembly  14  includes a base plate  42  and a pair of longitudinally extending flanges  44  that extend from the base plate  42 . The longitudinally extending flanges  44  divide the base plate into a first  46  and a second  48  side portion and a center portion  50 . A support plate  52  extends from the base plate  42  near the top  54  of the base plate  42  and perpendicular to the longitudinally extending flanges  44 . A pair of L-shaped mounting arms  56  is secured to the side  58  of the base plate  42  along the first side portion  46 . A third L-shaped mounting arm  56  is secured to the side  60  of the base plate  42  along the second side portion  48 . Each mounting arm  54  is preferably secured at an angle to the base plate  42  so that the entire heater assembly  14  may be positioned within the spacer  12 . Additionally, each mounting arm  56  includes a threaded flange  62  for use in securing the mounting arms  56  (and thus the heater assembly  14 ) to the threaded assembly mounts  38  of the spacer  12 . A pair of stand-offs  64  extend from opposing corners  66 ,  68  of the base plate  42  and support the appliance mounting plate  20 . 
   Still referring to  FIGS. 2-4 , the heater unit(s)  16  is secured to a mounting arm  56  of the heater assembly  14  and electrically connected to the high voltage circuit  67  of the high voltage terminal block  69 . The heater unit  16  is preferably a silicone laminate heater. However, in a particularly preferred embodiment, a pair of 50 watt silicone laminate heater units are used. In operation, the heater unit(s)  16  cycle as required to maintain the correct range of operating temperatures inside the enclosure  10 . 
   Still referring now to  FIGS. 2-4 , the fan  18  is secured to the support plate  52  of the heater assembly  14  and is electrically connected to the low voltage circuit  70  of the low voltage terminal block  72 . Preferably, the fan  18  is a 24 VDC, 90 mA fan with a life of at least five years of continuous duty. In operation, the fan  18  runs continuously to maintain a uniform temperature inside the enclosure  10 . 
   Still referring to  FIGS. 2-4 , the low voltage terminal block  70  and a high voltage terminal block  69  are positioned on the first  46  and second  48  side portions, respectively, of the heater assembly  14 . High and low voltage wiring entering the spacer  12  of the enclosure  10  through the apertures  28 , 30  is thus connected to the high or low terminal block to supply power (see  FIG. 4 ) to the heater unit(s)  16 , fan  18 , the appliance  100 , the control thermostat  74  and/or the low temperature thermostat  76  (as discussed below). 
   Referring now to  FIG. 2 , the appliance mounting plate  20  is secured over the heater assembly  14  and to the assembly mounts  38  of the spacer  12 . The appliance mounting plate  20  includes a central aperture  78  that is alignable with the center portion  50  of the base plate  42  of the heater assembly  14 . This arrangement allows electrical wiring (not shown) to be extended to the appliance  100  and also creates an open space within the enclosure for the circulation of air by the fan  18 . 
   A cutout  80  in the appliance mounting plate  20  is shaped to accept and be securable around the support plate  52  of the heater assembly  14 . A warning label  82  or similar indicia may be provided on the appliance mounting plate  20  so as to provide information to the user (e.g., installation/repair dates). A low temperature thermostat  76  is positioned on one side of the appliance mounting plate. As best shown in  FIG. 4 , the low temperature thermostat preferably makes a circuit at +32 F (0 C) and clears the circuit at +50 F (+10 C). A control thermostat  76  is positioned on a side of the appliance mounting plate  20  opposite the low temperature thermostat  76 . The control thermostat  74  is operable to set a desired temperature level at which to maintain the enclosure. A fuse  84 , preferably a 2-amp fuse, is also positioned on the appliance mounting plate  20  above the control thermostat  74 . As best shown in  FIG. 4 , the fuse  84  is electrically connected to the high voltage circuit  67 . 
   Referring now to  FIG. 2 , an appliance  100  is secured to the appliance mounting plate  20  over the central aperture  78 . Preferably, the appliance  100  is a light-emitting device (e.g., a strobe light). Particularly preferred strobe lights include the Select-A-Strobe Series from AMESCO, the 2700 Series by FARADAY®, or the Commander Series by Gemtex. 
   Referring now to  FIGS. 1 and 2 , the cover  22  is a dome-shaped cover that is positionable over the appliance  100 . The cover  22  has a flange  88  that extends from the rim  90  of the cover  22  and includes a plurality of threaded mounting holes  92 . In operation, the mounting holes  92  are aligned with the cover mounts  36  of the spacer  12  with the two parts then being secured together by screws  94  (see FIG.  1 ). The cover  22  is preferably a transparent polycarbonate cover having a thickness in the range of 0.1 to 0.3 inches. In a particularly preferred embodiment, the cover  22  has a thickness of 0.2 inches. 
   Still referring to  FIG. 2 , a neoprene gasket  96  is positioned in the joint between the cover  22  and the spacer  12  to assist in sealing the enclosure  10 . 
   It should be understood that the invention encompasses various modifications and alternative forms of embodiments. It should also be understood that these specific embodiments are not intended to limit the invention, but are intended to cover all modifications, equivalents and alternatives falling within the scope of the claims.