IMPINGEMENT JET FREEZER, SPENT REFRIGERANT DRAWN INTO INCOMING COLD REFRIGERANT STREAM AND MIXTURE SPRAYED THROUGH REFRIGERANT JETS

摘要

An impingement freezer (1) having a zoned freezing chamber (10) in which the temperature of each zone (22,24,26) is independently controllable so that the temperature profile within the impingement freezer (1) is coldest at a zone (22) adjacent the outlet and warmest at a zone (26) adjacent the inlet (12) for maximum thermodynamic usage of the refrigerant. Additionally, the velocity of each of the impingement jets is independently adjustable from zone to zone so that in the zone adjacent the entrance (12) of the freezing chamber (10), the impingement jets can be adjusted to have maximum velocity to produce maximum heat transfer coefficients and thereby an acceptable rate of cooling within the impingement jet freezer (1). Impingement jets are formed within nozzles (28-48) that are tapered in two orthogonal directions to prevent frost build-up. Circulation within the impingement jet freezer (1) is produced by venturi-like devices (74-84) driven by vaporization of incoming refrigerant. IMAGE