Deep freezer and method of freezing products

Abstract

A device and method is provided for cooling products, with a conveying belt which conveys the products through a cooling zone in which the products are exposed to an atmosphere which, by means of low-temperature gases, is brought to a temperature required for cooling the products. The conveying belt leads partially through an immersion bath consisting of liquefied low-temperature gas. At least one ventilator is mounted below the conveying belt such that it causes the temperature distribution in the cooling zone to be more uniform. Injection devices for liquefied low-temperature gas are provided, the injection devices being arranged in the proximity of the placing of the product onto the conveying belt below the part of the conveying belt loaded with the product, with a spraying direction aimed onto the conveying belt.

1 . Device for cooling products, comprising: 
 a conveying belt which conveys the products through a cooling zone in which the products are exposed to an atmosphere which, by means of low-temperature gases, is brought to a temperature required for cooling the products,    wherein the conveying belt leads partially through an immersion bath of liquefied low-temperature gas,    wherein at least one ventilator is mounted below the conveying belt such that it causes the temperature distribution in the cooling zone to be more uniform, and    wherein injection devices for liquefied low-temperature gas are provided, the injection devices being arranged in a proximity of placing of products onto the conveying belt below the part of the conveying belt loaded with the product, with a spraying direction aimed onto the conveying belt.    
   
   
       2 . Device according to  claim 1 , wherein the injection devices are arranged such below the part of the conveying belt loaded with the product that the liquefied low-temperature gas is in a heat-conducting contact with the underside of the conveying belt.  
   
   
       3 . Device according to  claim 1 , wherein at least one of said at least one ventilators is provided as a lower ventilator disposed under the conveying belt which is constructed as an axial-flow ventilator.  
   
   
       4 . Device according to  claim 2 , wherein at least one of said at least one ventilators is provided as a lower ventilator disposed under the conveying belt which is constructed as an axial-flow ventilator.  
   
   
       5 . Device according to  claim 3 , wherein the at least one lower ventilator has an axis situated in a plane parallel to the conveying belt.  
   
   
       6 . Device according to  claim 4 , wherein the at least one lower ventilator has an axis situated in a plane parallel to the conveying belt.  
   
   
       7 . Device according to  claim 3 , wherein the at least one lower ventilator has an axis which is oriented essentially perpendicular to a conveying direction of the products on the conveying belt.  
   
   
       8 . Device according to  claim 4 , wherein the at least one lower ventilator has an axis which is oriented essentially perpendicular to a conveying direction of the products on the conveying belt.  
   
   
       9 . Device according to  claim 5 , wherein the at least one lower ventilator has an axis which is oriented essentially perpendicular to a conveying direction of the products on the conveying belt.  
   
   
       10 . Device according to  claim 1 , wherein two lower axial-flow ventilators are provided under the conveying belt, and 
 wherein a partition wall is provided between the two axial flow ventilators.    
   
   
       11 . Device according to  claim 2 , Device according to  claim 1 , wherein two lower axial-flow ventilators are provided under the conveying belt, and 
 wherein a partition wall is provided between the two axial flow ventilators.    
   
   
       12 . Device according to  claim 10 , wherein rotational axes of the ventilators extend in a plane parallel to the conveying belt.  
   
   
       13 . Device according to  claim 11 , wherein rotational axes of the ventilators extend in a plane parallel to the conveying belt.  
   
   
       14 . Device according to  claim 12 , wherein said axes extend essentially perpendicularly to a conveying direction of the conveying belts.  
   
   
       15 . Device according to  claim 13 , wherein said axes extend essentially perpendicularly to a conveying direction of the conveying belts.  
   
   
       16 . Device according to  claim 1 , wherein the conveying belt is essentially made of special steel.  
   
   
       17 . Device according to  claim 2 , wherein the conveying belt is essentially made of special steel.  
   
   
       18 . Device according to  claim 3 , wherein the conveying belt is essentially made of special steel.  
   
   
       19 . Device according to  claim 5 , wherein the conveying belt is essentially made of special steel.  
   
   
       20 . Device according to  claim 7 , wherein the conveying belt is essentially made of special steel.  
   
   
       21 . Device according to  claim 10 , wherein the conveying belt is essentially made of special steel.  
   
   
       22 . Method of cooling products, the products being conveyed on a conveying belt through a cooling zone in which the products are exposed to an atmosphere which, by means of low-temperature gases, is brought to a temperature required for cooling the products, 
 wherein, by the immersion into low-temperature liquefied gas and by the injection of low-temperature gases into the device and by the cold atmosphere circulated by at least one ventilator, the conveying belt is brought to a temperature by which the products are cooled.    
   
   
       23 . Method according to  claim 22 , wherein low-temperature liquefied gas is sprayed from below onto the conveying belt and arrives on the underside of the conveying belt, so that a heat-conducting contact is established between the low-temperature liquefied gas and the underside of the conveying belt.  
   
   
       24 . An assembly for cooling products comprising: 
 a movable conveying belt traveling through a cooling zone where low temperature gases are applied to cool products carried by the conveying belt,    an immersion bath disposed in a travel path of the conveying belt and containing liquefied low temperatures gas to pre-cool the conveying belt at a position upstream of a location where products to be cooled are placed on the conveying belt,    at least one lower ventilator mounted below the conveying belt and operable to improve the uniformity of exposure of the low temperature gas to the conveying belt, and    a plurality of injection devices for spraying liquefied low temperature gas onto the conveying belt at a location carrying products to be cooled.    
   
   
       25 . An assembly according to  claim 24 , wherein the injection devices are disposed to spray the liquefied low temperature gas onto the conveying belt at locations intermediate the immersion bath and the at least one ventilator in the travel path of the conveying belt.  
   
   
       26 . An assembly according to  claim 24 , comprising at least one upper ventilator disposed above the conveying belt along portions of its product carrying path.  
   
   
       27 . An assembly according to  claim 25 , comprising at least one upper ventilator disposed above the conveying belt along portions of its product carrying path.  
   
   
       28 . An assembly according to  claim 24 , wherein said low temperature gas is nitrogen gas.  
   
   
       29 . An assembly according to  claim 24 , wherein the injection devices are disposed and configured so that the liquefied low temperature gas is in a heat conducting contact with the underside of the conveying belt.  
   
   
       30 . An assembly according to  claim 24 , wherein the at least one lower ventilator is constructed as an axial flow ventilator.  
   
   
       31 . An assembly according to  claim 30 , wherein the at least one lower ventilator has a rotational axis disposed in a plane parallel to the conveying belt product carrying travel path.  
   
   
       32 . An assembly according to  claim 24 , wherein the at least one lower ventilator comprises two lower ventilators separated by a partition wall.  
   
   
       33 . An assembly according to  claim 32 , wherein the injection devices are disposed to spray the liquefied low temperature gas onto the conveying belt at locations intermediate the immersion bath and the at least one ventilator in the travel path of the conveying belt.  
   
   
       34 . An assembly according to  claim 33 , comprising at least one upper ventilator disposed above the conveying belt along portions of its product carrying path.  
   
   
       35 . A method for cooling products comprising: 
 feeding products to a movable conveying belt traveling through a cooling zone where low temperature gases are applied to cool products carried by the conveying belt,    immersing the conveying belt in an immersion bath disposed in a travel path of the conveying belt and containing liquefied low temperatures gas to pre-cool the conveying belt at a position upstream of a location where products to be cooled are placed on the conveying belt,    providing at least one lower ventilator mounted below the conveying belt and operable to improve the uniformity of exposure of the low temperature gas to the conveying belt, and    injecting liquefied low temperature gas utilizing a plurality of injection devices for spraying liquefied low temperature gas onto the conveying belt at a location carrying products to be cooled.    
   
   
       36 . A method according to  claim 35 , wherein the injection devices are disposed to spray the liquefied low temperature gas onto the conveying belt at locations intermediate the immersion bath and the at least one ventilator in the travel path of the conveying belt.  
   
   
       37 . A method according to  claim 35 , wherein said low temperature gas is nitrogen gas.  
   
   
       38 . A method according to  claim 35 , wherein the injection devices are disposed and configured so that the liquefied low temperature gas is in a heat conducting contact with the underside of the conveying belt.