Helical conveyor freezer

A food cooling apparatus for the continuous cooling of food products, comprising:

• a thermally insulated enclosure;
• a helical conveyor disposed within said enclosure including a hollow cylindrical frame driven for rotation about a vertical axis, said frame being surrounded by and in driving engagement with a plurality of superimposed flights of a continuous foraminous conveyor for transporting food products upwardly along a helical path;
• refrigeration apparatus within said enclosure including heat exchange means and blower means to cool an atmosphere gas within said enclosure and circulate said atmosphere gas through and across said conveyor into contact with said food products on said conveyor;
• means for circulating said cooled atmosphere gas from said refrigeration apparatus immediately in a horizontal plane across the food products on a plurality of the lowermost of said flights of said conveyor into said hollow cylindrical frame for rapidly cooling incoming food products, said blower means circulating the atmosphere gas from the lowermost flights of said conveyor upwardly within said hollow cylindrical frame to a height above the uppermost flight of said conveyor and then radially outwardly of said vertical axis and then downwardly through all of the flights of said conveyor other than said plurality of said lowermost of said flights of said conveyor;
• and
• horizontal wall means extending substantially horizontally to separate said lowermost flights of said helical conveyor from the remaining flights of said helical conveyor and to cause the downwardly directed atmosphere gas to move radially outwardly to said refrigeration apparatus.

A method of freezing food products using mechanical refrigeration means, comprising:

• providing a thermally insulated enclosure having top and bottom walls with an entrance opening adjacent one of said walls and an exit opening adjacent the other of said walls;
• providing a continuous conveyor for transporting food products from said entrance opening to said exit opening on a helical path around a vertical axis, said conveyor having a plurality of superimposed flights;
• refrigerating an atmosphere gas in said enclosure to a reduced temperature and circulating said atmosphere gas across and through said food products on said conveyor;
• subjecting a plurality of the flights of said conveyor adjacent to said one wall to the reduced temperature atmosphere gas produced by said refrigerating, thereby raising the temperature of a portion of the atmosphere gas;
• and
• circulating the raised temperature gas across the food products on said conveyor in a vertical direction opposite to the direction in which said conveyor transports said food products.

Apparatus for freezing food products in a continuous process with an initial fast cooling stage to create an outer frozen surface to inhibit moisture loss, and a second stage in which food products are frozen completely at a rate which is slower than the rate of cooling during the initial fast cooling stage comprising:

• an insulated enclosure having an inlet for introducing food products into said enclosure and an outlet through which frozen food products are discharged;
• a continuous open mesh helical conveyor extending from said inlet to said outlet along a helical path having a plurality of superimposed flights extending around a vertical axis;
• refrigeration apparatus within said enclosure to cool atmosphere gas and circulate said atmosphere gas through and across said conveyor into contact with food products on said conveyor;
• means defining a first cooling zone in which said initial fast cooling of said products is accomplished, a plurality of the flights of said conveyor adjacent said inlet being within said first cooling zone;
• all of the atmosphere gas cooled by said refrigeration apparatus being initially discharged into said first cooling zone across said plurality of flights of said conveyor to subject said food products in said first cooling zone to atmosphere gas of the lowest temperature within said enclosure;
• means defining a second cooling zone in which said second stage of cooling of said food products is accomplished;
• said flights of said conveyor in said second cooling zone including all but said plurality in said first cooling zone and including flights of said conveyor adjacent said outlet;
• and
• means circulating atmosphere gas from said first cooling zone to the end of said helical conveyor adjacent said outlet and then circulating said atmosphere gas vertically through said flights of said conveyor within said second cooling zone.