Method and apparatus for ultrasonic freezing

Abstract

An apparatus for reducing a temperature of a product includes a housing in which cryogenic fluid is provided for being exposed to the product, and at least one ultrasonic transducer assembly disposed in the housing for generating ultrasonic energy to contact the cryogenic fluid and a surface of the product to facilitate heat transfer at the surface of the product. The cryogenic fluid can be selected from nitrogen and carbon dioxide.

1 . An apparatus for reducing a temperature of a product, comprising:
 a container;   a cryogenic substance provided to the container to reduce a temperature of at least a surface of the product;   a conveyor assembly for moving the product through the container for the surface of the product to be exposed to the cryogenic substance;   an ultrasonic transducer assembly disposed at the container in spaced relation from the product, the ultrasonic transducer assembly providing ultrasonic energy to the cryogenic substance to induce cavitation of nucleation at a surface of the product during exposure to the cryogenic substance.   
     
     
         2 . The apparatus according to  claim 1 , wherein the chamber comprises an immersion bath through which the conveyor and product are moved. 
     
     
         3 . The apparatus according to  claim 2 , wherein the ultrasonic transducer assembly is disposed in the immersion bath. 
     
     
         4 . The apparatus according to  claim 3 , wherein the ultrasonic transducer assembly is mounted to a sidewall of the container. 
     
     
         5 . The apparatus according to  claim 2 , wherein the ultrasonic transducer assembly is mounted above the immersion bath. 
     
     
         6 . The apparatus according to  claim 1 , wherein a transmission surface of the ultrasonic transducer assembly is disposed at a distance of up to 30 mm from the product. 
     
     
         7 . The apparatus according to  claim 1 , wherein the product is selected from a food product and a metallic product. 
     
     
         8 . The apparatus according to  claim 1 , wherein the cryogenic substance comprises nitrogen (N 2 ). 
     
     
         9 . The apparatus according to  claim 1 , further comprising a housing containing the container, the housing comprising an inlet and an outlet for the conveyor assembly. 
     
     
         10 . The apparatus according to  claim 9 , wherein the ultrasonic transducer assembly is mounted beneath the conveyor assembly. 
     
     
         11 . The apparatus according to  claim 9 , further comprising a barrier disposed in the container and having at least one nozzle through which the cryogenic substance may pass, the barrier aligned with the ultrasonic transducer assembly. 
     
     
         12 . An apparatus for reducing a temperature of a product, comprising:
 a housing in which cryogenic fluid is provided for being exposed to the product;   at least one ultrasonic transducer assembly disposed in the housing for generating ultrasonic energy to contact the cryogenic fluid and a surface of the product to facilitate heat transfer at the surface of the product.   
     
     
         13 . The apparatus according to  claim 12 , wherein the cryogenic fluid comprises a liquid bath. 
     
     
         14 . The apparatus according to  claim 13 , wherein the cryogenic fluid comprises nitrogen. 
     
     
         15 . The apparatus according to  claim 12 , wherein the cryogenic fluid comprises a fog. 
     
     
         16 . The apparatus according to  claim 15 , wherein the cryogenic fluid comprises nitrogen. 
     
     
         17 . A method of reducing a temperature of a product, comprising:
 exposing a surface of the product to a cryogenic substance for heat transfer at said surface;   providing ultrasonic energy to the cryogenic substance and the product for destroying nucleation at the surface of the product.   
     
     
         18 . The method according to  claim 17 , wherein the exposing comprises immersing at least a portion of the surface of the product in the cryogenic substance, and the destroying comprises cavitating the nucleation at the surface of the product. 
     
     
         19 . The method according to  claim 17 , wherein the exposing comprises spraying the surface of the product with the cryogenic substance. 
     
     
         20 . The method according to  claim 17 , wherein the cryogenic substance is selected from nitrogen and carbon dioxide.