Abstract: An improved dry ice pelletizer and method for significantly increased pellet production. The improvement consists of multiple injection ports used for the timed introduction of liquid carbon dioxide into a dry ice extrusion cylinder so that the cylinder can be more completely filled with carbon dioxide snow before extrusion takes place. Part of the improvement stems from the use of a solid mass of carbon dioxide, called a puck, which is chamfered and serves to capture carbon dioxide vapor and snow within the compression cylinder. The resulting improvement in carbon dioxide pellet output is roughly 400% over that achieved by conventional methods. The inventive improvement may also be installed as a retrofit to conventional dry ice pellet extrusion machines.

Abstract: A method and apparatus for effecting the cooling of a stream of air or gas by sublimation of dry ice particles utilizes an upwardly directed, variable velocity stream of air to maintain a supply of dry ice particles provided on a moving perforated conveyor in a fluidized bed condition to maximize the rate of sublimation of the dry ice particles. The cooled air may then be employed to effect the rapid and efficient freezing of a plurality of food articles passing through the same insulated chamber as the dry ice particle conveyor is located, or an adjacent insulated chamber.