Air defrost system using secondary air band components

A refrigerated display cabinet having an access opening for communicating a storage and display space within the cabinet with the ambient atmosphere, adjacent inner and outer outlets extending across one edge of said access opening;

• corresponding adjacent inner and outer inlets extending across an opposite edge of said access opening;
• a first conduit extending from said inner inlet around said cabinet to said inner outlet;
• a second conduit extending from said outer inlet around said cabinet in said outer outlet;
• refrigeration means is one of said first and second conduits;
• first air circulating means in said one conduit for propelling air over and/or through said refrigeration means to the outlet of said conduit and across said access opening in the form of a primary air curtain to the inlet of said one conduit, wherein said air circulating means maintains the flow of air through said one conduit continuously in the same direction to maintain a substantially continuous air curtain during refrigeration and defrost cycles of said display cabinet;
• second air circulating means for directing a flow of air through the other of said first and second conduits in a first direction during the refrigeration cycle and in a second direction, substantially opposite said first direction, during the defrost cycle;
• and means providing a directed air flow path from said other conduit to said one conduit upstream of the refrigeration means during the defrost cycle, whereby during the defrost cycle air is caused to flow from said other conduit into said one conduit and over and/or through said refrigeration means to defrost same.

In an upright refrigerated display cabinet having a top, a bottom, a rear, a front side, and an access opening in said front side for communicating a storage and display space within the cabinet with the ambient atmosphere, adjacent inner and outer outlets extending across one edge of said access opening;

• corresponding adjacent inner and outer inlets extending across the opposite edge of said access opening;
• a first conduit extending from said inner inlet around said cabinet to said inner outlet;
• a second conduit extending from said outer inlet around said cabinet to said outer outlet;
• refrigeration coil means in said first conduit;
• and first air circulating fan means in said first conduit for propelling air across said coil means, to said inner outlet, and across said access opening in the form of a primary air curtain to said inner inlet;
• the improvement comprising:
• second air circulating means for directing the flow of air through said second conduit in a first direction during the refrigeration cycle and for drawing ambinet air into said second conduit during a defrost cycle and directing the flow of air in a second direction, substantially opposite said first direction, during the defrost cycle;
• and
• means for directing air from said second conduit to said first conduit during the defrost cycle;
• wherein the flow of air through said first conduit is maintained continuously in the same direction to maintain a substantially continuously primary air curtain during both the refrigeration and defrost cycles.

A refrigerated display cabinet having an access opening for communicating a storage and display space within the cabinet with the ambient atmosphere;

• adjacent inner and outer outlets extending across one edge of said access opening;
• corresponding adjacent inner and outer inlets extending across an opposite edge of said access opening;
• a first conduit extending around said cabinet between said inner inlet and said inner outlet;
• a second conduit extending around said cabinet between said outer inlet and said outer outlet;
• refrigeration means in one of said first and second conduits;
• first air circulating means in said one conduit for circulating air through said one conduit and across said access opening during a refrigeration cycle in the form of a first air curtain;
• second air circulating means for circulating air through the other of said first and second conduits and across said access opening during a refrigeration cycle in the form of a second air curtain;
• and means for reversing the air flow direction of one of said first and second air circulating means and maintaining the air flow direction of the other of said first and second air circulating means during the defrost cycle, whereby said other air circulating means maintains a substantially continuous air curtain across said access opening during refrigeration and defrost cycles of said display cabinet, and whereby during the defrost cycle air is caused to flow around and/or through said refrigeration means to defrost same.