Direct current air curtain

Abstract

Direct current air curtains are provided, which may be used to help reduce or prevent the exchange of heat between different areas. The direct current air curtain may be used in a variety of applications, including trailers, rail cars, vehicles and containers.

1 . A system comprising:
 a refrigerated trailer comprising:
 a door, the door having open and closed positions; and 
 a refrigeration unit attached to the refrigerated trailer, the refrigeration unit comprising a power source; and 
   an air curtain comprising:
 a housing comprising an air inlet and an air outlet, the housing being sized to fit within the trailer adjacent to the door, the air inlet being offset from the air outlet; 
 a direct current motor attached to the housing; 
 an electronic controller electrically coupled to the direct current motor and the power source of the refrigeration unit; 
 a fan operatively coupled to the direct current motor; and 
 a sensor positioned in the door and in communication with the electronic controller, 
   wherein the sensor signals the electronic controller when the door is in the open position, the electronic controller activating the direct current motor to rotate the fan after receiving the sensor signal,   wherein the fan pulls air from within the trailer into the housing unit through the air inlet and redirects the air so that the air is expelled through the air outlet.   
     
     
         2 . The system of  claim 1 , wherein the air curtain requires around 12 volts electric potential and between 20 and 40 amps current. 
     
     
         3 . The system of  claim 1 , wherein the direct current motor is a brushless direct current motor. 
     
     
         4 . The system of  claim 1 , wherein the air curtain is operable to generate an air flow of between 1000 and 1500 cubic feet per minute. 
     
     
         5 . The system of  claim 1 , wherein the air curtain is operable within an environment having a temperature of between −29 degrees C. and 43 degrees C. 
     
     
         6 . The system of  claim 1 , wherein the air curtain generates an air flow that is oriented within 0 to 20 degrees of a plane of a door opening. 
     
     
         7 . The system of  claim 1 , wherein the air curtain generates around 85 decibels or less noise when activated. 
     
     
         8 . The system of  claim 7 , wherein the air curtain generates approximately 80 decibels or less of noise when activated. 
     
     
         9 . The system of  claim 4 , wherein the air curtain generates an air flow of between 1100 and 1300 cubic feet per minute. 
     
     
         10 . The system of  claim 1 , wherein the power source of the refrigeration unit comprises an alternator and a battery, and
 wherein the direct current motor and the electronic controller are powered by an electrical output of the alternator, the battery, or the alternator and the battery of the refrigeration unit.   
     
     
         11 . The system of  claim 1 , wherein the air inlet is offset from the air outlet by roughly 90 degrees. 
     
     
         12 . The system of  claim 1 , wherein the fan is a tangential fan. 
     
     
         13 . An air curtain comprising:
 a housing comprising an air inlet and an air outlet;   a direct current motor attached to the housing, the direct current motor comprising an output shaft;   an electronic controller electrically coupled to the direct current motor;   a sensor in communication with the electronic controller and configured to signal the electronic controller to activate and deactivate the direct current motor; and   a fan positioned within the housing and mechanically coupled to the output shaft of the direct current motor,   wherein the air curtain generates air flow between 1000 and 1500 cubic feet per minute when in operation.   
     
     
         14 . The air curtain of  claim 13 , wherein the air curtain generates less than 85 decibels of noise 
     
     
         15 . The air curtain of  claim 14 , wherein the air curtain generates less than 80 decibels of noise when in operation. 
     
     
         16 . The air curtain of  claim 13 , wherein the air curtain generates air flow between 1100 and 1300 cubic feet per minute when in operation. 
     
     
         17 . The air curtain of  claim 13 , wherein the air curtain uses approximately 12 volts of electric potential and between 20 and 40 amps current. 
     
     
         18 . The air curtain of  claim 13 , wherein the direct current motor is moisture tight. 
     
     
         19 . The air curtain of  claim 13 , wherein the housing has outside dimensions of approximately 1 m in length, 25 cm in height and 22 cm or less in depth. 
     
     
         20 . The air curtain of  claim 13 , wherein the air outlet further comprises a positionable nozzle. 
     
     
         21 . The air curtain of  claim 13 , further comprising another fan,
 wherein the output shaft of the direct current motor extends away from the direct current motor on each end of the motor, and   wherein one of the fan and the other fan is mechanically coupled to the output shaft adjacent to each end of the direct current motor.   
     
     
         22 . The air curtain of  claim 13 , wherein the air curtain is operable within an environment having a temperature range of −29 degrees C. to 43 degrees C. 
     
     
         23 . The air curtain of  claim 13 , wherein the fan is a tangential fan.