Frost reduction by air curtain

Abstract

An ultra-low temperature freezer, including a cabinet with a freezer compartment maintained within a certain temperature range, a door providing a seal with the cabinet when engaged with the cabinet, a catch basin at the bottom of the cabinet for collecting air, and a distribution channel fluidly connected to the catch basin, for recirculating the air collected from the catch basin to the top of the cabinet, the distribution channel at the top of the cabinet pushing compressed air across the front of the cabinet and forming an air curtain and thermal barrier to incoming warmer air.

1 . An ultra-low temperature freezer, comprising:
 a cabinet with a freezer compartment maintained within a certain temperature range;   a door providing a seal with the cabinet when engaged with the cabinet;   a catch basin at the bottom of the cabinet for collecting air; and   a distribution channel fluidly connected to the catch basin, for recirculating the air collected from the catch basin to the top of the cabinet, the distribution channel at the top of the cabinet pushing compressed air across the front of the cabinet and forming an air curtain and thermal barrier to incoming warmer air.   
     
     
         2 . The apparatus of  claim 1 , wherein the distribution channel is disposed exterior to the cabinet and configured to compress the air. 
     
     
         3 . The apparatus of  claim 1 , further comprising nozzles disposed on the distribution channel at the top of the cabinet for outputting the compressed air. 
     
     
         4 . The apparatus of  claim 1 , further comprising at least two plates with an opening in between, on the distribution channel at the top portion of the cabinet for forming the air curtain. 
     
     
         5 . The apparatus of  claim 1 , wherein the distribution channel is disposed between insulation and an evaporator. 
     
     
         6 . The apparatus of  claim 1 , wherein the distribution channel includes a tortured path from a front of the freezer to the back of the freezer and back to the front of the freezer, where the front of the freezer is the plane where the door seals the cabinet. 
     
     
         7 . The apparatus of  claim 1 , wherein the distribution channel includes a middle portion between the door and a second door connected to the cabinet, providing an air curtain from the middle portion to the catch basin. 
     
     
         8 . An ultra-low temperature refrigeration apparatus, comprising:
 a cabinet with a freezer compartment maintained within a certain temperature range;   a door providing a seal with the cabinet when engaged with the cabinet;   a collection means at the bottom of the cabinet for collecting gas; and   a distribution means fluidly connected to the collection means, for recirculating the gas collected from the collection means to the top of the cabinet, the distribution means at the top of the cabinet pushing compressed gas across the front of the cabinet and forming a curtain and thermal barrier to warmer outside environment.   
     
     
         9 . The apparatus of  claim 8 , wherein the distribution means is disposed exterior to the cabinet. 
     
     
         10 . The apparatus of  claim 8 , further comprising nozzles disposed on the distribution means at the top of the cabinet for outputting the compressed gas. 
     
     
         11 . The apparatus of  claim 8 , further comprising at least two plates with an opening in between, on the distribution means at the top portion of the cabinet for forming the curtain. 
     
     
         12 . The apparatus of  claim 8 , wherein the distribution means is disposed between insulation and an evaporator. 
     
     
         13 . The apparatus of  claim 8 , wherein the distribution means includes a tortured path from a front of the apparatus to the back of the apparatus and back to the front of the apparatus, where the front of the apparatus is the plane where the door seals the cabinet. 
     
     
         14 . The apparatus of  claim 8 , wherein the distribution means includes a middle portion between the door and a second door connected to the cabinet, providing the curtain from the middle portion to the collection means. 
     
     
         15 . A method of an ultra-low temperature freezer, comprising:
 collecting air at a catch basin at the bottom of a freezer cabinet when opening a door of the freezer;   compressing and distributing the air collected from the catch basin to the top of the cabinet via a distribution channel; and   outputting the compressed air across the front of the cabinet from the top of the cabinet to the bottom of the cabinet toward the catch basin and forming an air curtain and thermal barrier to incoming warmer air.   
     
     
         16 . The method of  claim 15 , further comprising of recirculating the air outputted across the front of the cabinet and into the catch basin via a distributing channel. 
     
     
         17 . The method of  claim 15 , further comprising cooling the air through the distribution channel disposed adjacent to an evaporator. 
     
     
         18 . The method of  claim 15 , further comprising of actively cooling and compressing the air circulating through the distribution channel.