Low temperature display merchandiser

A refrigerated merchandiser having a cabinet with an open front product display area, primary air system means comprising evaporator means constructed and arranged for refrigerating primary air to maintain a predetermined exit air temperature during refrigerating operations and air moving means for circulating such primary air in a first direction to maintain a substantially uniform target temperature throughout the display area, said primary air circulating means forming a first primary air curtain discharged downwardly across the open front of the display area from the top of the merchandiser cabinet, vertically adjustable shelf means in said display area and having an upper product supporting surface, said shelf means being constructed and arranged with air channeling duct means forming a part of the primary air circulating means and discharging at least one additional curtain of primary air downwardly from the front of the shelf means immediately inwardly of the first primary air curtain at the open front of the display area, the air flow of said primary air curtains being the only positive air movement at said display area, at least one other air system means constructed and arranged for forming a secondary air curtain discharged downwardly across the open front of the display area immediately outwardly of said primary air curtains and returning said secondary air into the cabinet for recycling, and defrost means constructed and arranged for periodically defrosting said evaporator means including means for reversing said air moving means for circulating primary defrost air in a second reverse air flow defrosting direction through the evaporator means while maintaining the normal operation of said other air system means and inducing the return of primary defrost air into the cabinet with the secondary air.

A refrigerated food merchandiser having a cabinet with an open front product display area having a plurality of vertically adjustable shelves therein, a primary cold air recycling system constructed and arranged for maintaining substantially constant food product temperatures of about 0.degree. F. or lower in the product area, said primary air system including a primary air passage through the cabinet having a primary air discharge at the upper front of the display area and a primary air return at the lower front of the display area and including the formation of a first primary air curtain downwardly across the open front of the display area between said primary discharge and return openings, said shelves being constructed and arranged with air channeling duct means in communication with the primary air passage to receive refrigerated air therefrom and to form a plurality of other successive primary low temperature air curtains discharged downwardly across discrete display area sections of the open front and on the inward side of the first primary air curtain to the primary return opening, the primary air system having primary air moving means for circulating the primary air in a first refrigerating direction through the primary air passage in the cabinet and the shelf duct means to form said primary air curtains across the open front and to said primary return opening for recycling and discharging primary evaporator means constructed and arranged to cool such primary air in said primary air passage to maintain a predetermined coil exit air temperature of said primary air for providing the substantially constant product temperature in said display area, a secondary non-refrigerated air recycling system having a closed air passage through the cabinet with a secondary air discharge adjacent to the primary air discharge and a secondary air return adjacent to said primary air return, including secondary air moving means for circulating secondary air through said secondary passage and forming a downwardly discharged secondary air curtain across the open front of the cabinet on the outward side of the primary air curtains to said secondary air return, and defrost means associated with said primary air system and constructed and arranged for periodically defrosting said primary evaporator means thereof including means for reversing said primary air moving means for circulating heated primary defrost air in a second reverse air flow defrosting direction through and in heat exchange relation with said evaporator means and thence outwardly through the primary return opening while maintaining the normal operation of said secondary air system including air flow into the adjacent secondary air return to thereby induce the flow of primary defrost air into the secondary air return during defrosting operations.