Method and Apparatus for Cooling and/or Deep-Freezing Products, Especially Food Products, Implementing the Injection of Two Cryogenic Liquids

Abstract

The invention relates to a method for cooling materials, in particular food, in a cooling apparatus, the cooling being completely or partially carried out by contacting the materials with a cryogenic liquid. Said method is characterized in that the contacting is carried out by means of the injection of two cryogenic liquids, nitrogen and CO 2 . The liquid nitrogen and the liquid CO 2 are injected either separately, into at least two injection points of the apparatus, or by mixing both cryogenic fluids at the injection point. The invention is of use if the apparatus being utilized is a mixing, batch mixing, or grinding chamber, with the injection being carried out into the body of the material in the bottom portion of the chamber.

1 - 7 . (canceled) 
     
     
         8 . A process for chilling products in a chilling device, the device used being a chamber of a mixer, blender, or grinder containing a mass of product to be chilled, comprising injecting liquid nitrogen and liquid CO 2  within the mass of product in a bottom part of the chamber, the injection of liquid nitrogen and liquid CO 2  being performed separately at at least two injection points of the device. 
     
     
         9 . The chilling process of  claim 8 , wherein the device comprises a forced convection system in a top part of the chamber thereby allowing a recycle and use of a refrigerating power of cold gases that result from vaporization of the liquid nitrogen and liquid CO 2 . 
     
     
         10 . The chilling process of  claim 8 , further comprising the steps of:
 discontinuing the injection of the liquid nitrogen and liquid CO 2  for a given stop time; and   measuring a temperature in the mass of product to be treated, wherein:
 if the measured temperature is substantially equal to said setpoint temperature the device is changed to shutdown mode and the injection of liquid nitrogen and liquid CO 2  is completed; and 
 if the measured temperature is greater than the setpoint temperature, the continuous injection of liquid nitrogen and liquid CO 2  is resumed until the setpoint temperature is obtained. 
   
     
     
         11 . The chilling process of  claim 8 , wherein the device is provided with an overflow gas extractor having a break either in between the device and the extractor or in between opposite ends of the device, such that:
 due to the presence of the break, liquids condensing in the extractor are inhibited from being returned to the device; and   due to the presence of the break, a discharge velocity of cold gases resulting from vaporization of the injected liquid nitrogen and liquid CO 2  is limited to a value below a velocity that would otherwise allow any solid CO 2  present in the chamber from escaping the chamber with the cold gases.   
     
     
         12 . The chilling process of  claim 8 , wherein the products are food products.