Abstract: A carbon dioxide snow generator is disclosed which has a purge conduit for controllably delivering a blast of pressurized fluid at the inner surfaces of the generator to dislodge and remove any residual or clogging deposits of carbon dioxide snow. A vapor loop for such a generator is also disclosed which provides an initial blast of relatively warm carbon dioxide gas at startup which gas entrains and removes any residual liquid before it can freeze in the apparatus.

Abstract: A system for heating or cooling articles conveyed in a vertical helical path is defined by an endless conveyor belt driven at its inner edge by contact with a rotating drum and a circulating heat exchange fluid propelled horizontally onto the articles by axial flow fans rotating in a vertical plane. The system features a novel arrangement employing scroll means for confining the circulating heat exchange fluid to a substantial portion of the helical path and location of fan means such that the heat exchange fluid is propelled in push-pull manner from the discharge side of one fan means to the intake or suction side of a second fan means. In the preferred embodiment directed to refrigeration of conveyed articles, more particularly foodstuffs to be frozen, the conveyor is located within an insulating housing. Further featured novelty includes location of the driving means for the rotating drum externally of the housing and directing of refrigerant, such as liquid CO.sub.

Abstract: A system for heating or cooling articles conveyed in a vertical helical path is defined by an endless conveyor belt driven at its inner edge by contact with a rotating drum and a circulating heat exchange fluid propelled horizontally onto the articles by axial flow fans rotating in a vertical plane. The system features a novel arrangement employing scroll means for confining the circulating heat exchange fluid to a substantial portion of the helical path and location of fan means such that the heat exchange fluid is propelled in push-pull manner from the discharge side of one fan means to the intake or suction side of a second fan means. In the preferred embodiment directed to refrigeration of conveyed articles, more particularly foodstuffs to be frozen, the conveyor is located within an insulating housing. Further featured novelty includes location of the driving means for the rotating drum externally of the housing and directing of refrigerant, such as liquid CO.sub.

Abstract: Scrap tires containing magnetic components and non-magnetic rubber and cord components are cooled in a cryogenic freezer to the embrittlement temperature, comminuted in a comminution device and passed through a series of screening and density classification operations followed by magnetic material separation and further cryogenic size reduction to produce a product rubber crumb having a particle size of about 1/20 inch or less.