Temperature distribution improvement in refrigerated container

Abstract

The fan of a refrigeration machine operatively connected to a container box is operated in one direction during normal operation and is periodically operated in the opposite direction in order to reverse the direction of airflow to and from the container box so as to thereby promote a more uniform temperature distribution within the container box. A door is automatically closed when operating in the reverse direction so as to accelerate the airflow speed into the container box.

1 . A method of operating a refrigerated container of the type having a refrigeration machine at one end of the container with the refrigeration machine having a fan for circulating warmer return air through an evaporator coil to be cooled and then to flow rearwardly to the container to cool its cargo, comprising the steps of:
 during normal operation, operating the fan in one direction so as to draw in return air at one end of the refrigeration machine and discharge it from the other end thereof; and   periodically reversing the direction of the fan so as to draw in return air at the other end of the refrigeration machine and discharge it from the one end thereof; whereby the air in the refrigerated container is mixed so as to provide a more uniform temperature distribution throughout.   
     
     
         2 . A method as set forth in  claim 1  wherein said fan operates in a blow-through mode during normal operation and as a draw-through mode during periodic reverse operation. 
     
     
         3 . A method as set forth in  claim 1  wherein said refrigeration machine one end is near the top thereof and the other end is near a bottom end thereof. 
     
     
         4 . A method as set forth in  claim 1  and including the steps of providing a door near said one end and opening said door when said fan is operating in said one direction and closing it when operating in said reverse direction. 
     
     
         5 . A refrigeration machine for use with a container of a type for holding cargo to be refrigerated, comprising:
 an evaporator coil;   a fan for causing warm air to be drawn in from one portion of the container box, to pass through the evaporator coil to be cooled, and then flow outwardly from the refrigeration machine to another portion of the container box; and   a control for selectively operating the fan in one direction so as to draw in air from said container box one portion and return cooled air to said container box other portion and, periodically, reversing the direction of the fan such that the air is drawn in from said container box other portion and the cooled air is returned to said container box one portion.   
     
     
         6 . A refrigeration machine as set forth in  claim 5  and including a door near said box one portion and so as to be automatically opened when said fan is operated in said one direction and closed when said fan is operating in said reverse direction.