Abstract: The present invention provides a method and apparatus for using hot gas to defrost sequentially each refrigerated display case (evaporator) in a group of refrigerated display cases (evaporators). A unique cross-feed line connects the distributor and the evaporator suction line for each evaporator in the group of evaporators. Like a typical hot gas defrost system, the sequential hot gas defrost system may be time-initiated and time-terminated or time-initiated and temperature-terminated. Each evaporator in the group of evaporators is defrosted in turn while the remaining evaporators in the group continue to operate in the refrigeration mode. A unitary combination check valve and orifice simplifies the sequential hot gas defrost refrigeration system.

Abstract: The invention is a method and a defroster control circuit to sequentially defrost a series of refrigerated display cases. The method begins by operating the series of refrigerated display cases during a normal refrigeration mode. At the beginning of the refrigeration mode, a refrigeration time is set to zero and an elapsed refrigeration time is subsequently monitored. When the refrigeration time equals an activation time, a defrost mode begins and a defrost cycle for the first case starts. The defrost mode for the first case terminates based either on a defrost time criterion or a defrost temperature criterion. After the first refrigerated display case is defrosted, a refrigeration mode is restarted for the first case. After the first refrigerated display case is defrosted, the other refrigerated display cases in the series of refrigerated display cases are then sequentially defrosted.

Abstract: The invention is for an enclosable evaporator/defroster unit for a refrigerated display case. The refrigerated display case has a cabinet with a floor, a ceiling, a front wall, a rear wall, and side walls. There is an access opening in one of the front wall, the rear wall and the side walls. An air duct extends around the cabinet for conducting a current of air. The air duct forms a substantially closed conduit. There is a gap in the conduit that coincides with the access opening in the cabinet. A fan circulates air in the air duct. An evaporator coil is positioned in the air duct to cool the circulating air. A defroster unit is also positioned near the evaporator coils to melt the condensation on the evaporator coil. The defroster unit has a heater, dampers, and an actuator for moving the dampers between an open and a closed position.

Abstract: The invention is a method and a defroster control circuit to sequentially defrost a series of refrigerated display cases. The method begins by operating the series of refrigerated display cases during a normal refrigeration mode. At the beginning of the refrigeration mode, a refrigeration time is set to zero and an elapsed refrigeration time is subsequently monitored. When the refrigeration time equals an activation time, a defrost mode begins and a defrost cycle for the first case starts. The defrost cycle for the first case terminates based either on a defrost time criterion or a defrost temperature criterion. After the first refrigerated display case is defrosted, a refrigeration cycle is restarted for the first case. After the first refrigerated display case is defrosted, the other refrigerated display cases in the series of refrigerated display cases are then sequentially defrosted.