Air distribution means for a refrigerated meat case

Claim 1

A refrigerated display case having a refrigerated space and including: a support for articles to be stored in said refrigerated space, a plenum chamber located above said support, a second plenum chamber located below said support, an air duct between said second plenum chamber and said first plenum chamber including therein, means for maintaining the air in said second plenum chamber at less than atmospheric pressure and maintaining the air in said first plenum chamber at greater than atmospheric pressure, cooling means located in said air duct capable of maintaining the temperature of said air in said first plenum chamber lower than the temperature of the air in said second plenum chamber, porous conductive means located between said first plenum chamber and said refrigerated space capable of restricting the flow of air so as to diffuse the air as it passes from said first plenum chamber to said refrigerated space, whereby air is exhausted from the lower portion of said space into said second plenum chamber and thereafter circulated by said cooling means through said air duct to said first plenum chamber and moved through said porous conductive material from said first plenum chamber into said space and by gravity through said space to said second plenum chamber, to thereby cause the circulation of cool air through said space and past said support in a manner substantially equal to gravity flow.