Abstract: A freezer system which partially freezes food products through conductive heat transfer with rotating contact freezers prior to complete freezing of the food products in an enclosed convection freezer. Food products sequentially contact outer surfaces of two rotating contact freezers, which partially freezes the food products to first and second predetermined depths. The partially frozen food products then enter an enclosed convection freezer for complete freezing. Partial freezing of the food products prior to a complete freeze of the food products provides for a greatly increased rate of production of high quality frozen food products.

Abstract: A drum contact freezer system which reduces or eliminates a stagnant layer of refrigerant on an interior surface of the drum freezers is provided. A boiling refrigerant is sprayed into the interior of the drum freezers to scrub an interior surface thereof having the stagnant layer. This scrubbing reduces or eliminates the stagnant layer and thus provides an enhanced rate of heat transfer. The boiling refrigerant is preferably in a temperature range of approximately -100.degree. F. to -40.degree. F. at or near atmospheric pressure. Additionally, the boiling refrigerant may be circulated within the drum freezers by providing troughs on the interior surface thereof to help lift the boiling refrigerant and prolong contact between the boiling refrigerant and the interior surface of the drum freezers to provide a further enhanced rate of heat transfer.

Abstract: Refrigeration apparatus for cooling or freezing products such as protein materials includes a drum through which heat transfer fluid is circulated. A belt is wrapped around part of the drum surface and the product to be refrigerated is applied to the drum surface, being pressed thereagainst by the belt. Either liquid or triple point carbon dioxide is circulated through the drum to cool the product in contact therewith. Other heat transfer fluids such as D-Limonene or DOWTHERM may also be circulated through the drum. A tank and related apparatus for cooling the heat transfer fluid is also disclosed.

Abstract: Refrigeration apparatus for cooling or freezing products such as protein materials includes a drum through which heat transfer fluid is circulated. A belt is wrapped around part of the drum surface and the product to be refrigerated is applied to the drum surface, being pressed thereagainst by the belt. Either liquid or triple point carbon dioxide is circulated through the drum to cool the product in contact therewith. Other heat transfer fluids such as D-Limonene or DOWTHERM may also be circulated through the drum. A tank and related apparatus for cooling the heat transfer fluid is also disclosed.

Abstract: A cryogenic freezer having a thermally insulated tunnel-like enclosure with an entrance and an exit and means for conveying products being frozen therethrough. Products are contacted with liquid cryogen at a region generally near the entrance and a blower located closer to the entrance than to the exit controls flow of cryogen vapor. Upstream and downstream baffles and dampers associated with blower are linked together for complementary movement to selectively regulate the upstream and downstream flow of vapor discharged from the blower. Additional blowers circulate the cold cryogenic vapor transverse to the direction of the conveying means. The temperature of vapor leaving the region of the entrance is monitored the orientation of the baffle and damper arrangement is adjusted in accordance with the temperature monitored. The food products can be contacted by liquid nitrogen in a reservoir facilitates cleaning and retards inefficient vaporization.

Abstract: A cabinet freezer efficiently utilizes a liquid cryogen refrigerant in conjunction with a spiral conveyor which conveys a product load through a temperature gradient within the freezer. The freezer has a lower inlet and an upper outlet for the conveyor and food load thereon. The escape of cryogen vapors created in the freezer from the liquid cryogen is controlled such that at least about 80% of the vapors exit through the upper outlet which is at the warmest zone established as a part of the temperature gradient in the freezer.

Abstract: After baking bread dough goods in an oven at about 375.degree. F., their temperature is lowered to at least about 120.degree. F., and they are then cryogenically cooled to about 45.degree. F. or below in about 5 to about 15 minutes. The baked goods are then maintained at a temperature of about 37.degree. F. to about 45.degree. F. for at least about 25 minutes to effect substantial starch crystallization; after which time, slicing, bagging and freezing are carried out. Cryogenic cooling is preferably effected in a CO.sub.2 cooler, and the cooled baked goods are maintained at about 40.degree. F. for between about 25 and about 60 minutes prior to freezing by movement along an insulated conveyor which is cooled by circulation therethrough of cold CO.sub.2 vapor exhaust from the CO.sub.2 cooler.