Insulated cabinet with interchangeable heat transfer unit

Abstract

Insulated cabinets with interchangeable heat transfer units disposed on the top thereof are disclosed and means for improving the air circulation both in the heat transfer units and within the enclosed cabinet. The heat transfer units may be refrigeration type units, freezer type units, heating type units, warming type units or proofing units. Each of the heat transfer units includes a rectangular opening in the bottom thereof to which is attached a duct through which heated or cooled air is forced. The duct has parallel front and rear walls and inclined side walls which taper to reduce the cross section of the air flow. The duct is a sliding fit inside a tunnel which extends vertically along the back wall of the cabinet. The tunnel is provided with two columns of louvers along its entire length through which the air from the duct flows. Air exiting the louvers is deflected by a baffle plate which extends the full width of the rear of the cabinet. The edge portions of the baffle plate are perforated. The air thus must move out forward through the louvers then laterally across the solid portion of the baffle plate before turning forward again through the perforations in the baffle plate into the interior of the cabinet. The improved air flow greatly reduces temperature differences within the cabinet when used as an oven, and the air flow over the heating elements is more uniform, reducing hot spots and thus prolonging their life.