Cryogenic biological preservation unit with integrated cryocooler and nitrogen supply

Abstract

A system for the cryogenic preservation of biological material having a dedicated cryocooler integrated with an insulated vessel and preferably a membrane separator which processes feed air for supplying gaseous nitrogen into the insulated vessel for condensation by refrigeration provided by the dedicated cryocooler.

1 . A cryogenic biological preservation apparatus comprising: 
 (A) a nitrogen source, an insulated vessel, and means for providing gaseous nitrogen from the nitrogen source into the insulated vessel; and    (B) a cryocooler mounted on the insulated vessel, said cryocooler having a cold finger positioned to provide refrigeration to the insulated vessel.    
   
   
       2 . The apparatus of  claim 1  wherein the nitrogen source is a membrane separator, and further comprising means for providing feed air to the membrane separator.  
   
   
       3 . The apparatus of  claim 2  wherein the means for providing feed air to the membrane separator comprises a prefilter and an oil removal filter.  
   
   
       4 . The apparatus of  claim 1  wherein the insulated vessel contains a pool of liquid nitrogen.  
   
   
       5 . The apparatus of  claim 4  wherein the means for providing gaseous nitrogen from the nitrogen source into the insulated vessel includes a control valve which is adjusted based on the level of the pool of liquid nitrogen within the insulated vessel.  
   
   
       6 . The apparatus of  claim 4  wherein the means for providing gaseous nitrogen from the nitrogen source into the insulted vessel provides the gaseous nitrogen into the pool of liquid nitrogen.  
   
   
       7 . The apparatus of  claim 1  wherein the insulated vessel comprises a lid and further comprises means for vapor to flow out from the insulated vessel around the lid.  
   
   
       8 . The apparatus of  claim 1  wherein the cryocooler is a pulse tube refrigerator.  
   
   
       9 . The apparatus of  claim 4  further comprising at least one biological sample above the pool of liquid nitrogen.  
   
   
       10 . A method for operating a cryogenic biological preservation unit comprising: 
 (A) passing gaseous nitrogen from a nitrogen source into an insulated vessel containing at least one biological sample; and    (B) providing refrigeration from a cryocooler to the insulated vessel and condensing some of the gaseous nitrogen to form liquid nitrogen within the insulated vessel.    
   
   
       11 . The method of  claim 10  wherein the nitrogen source is a membrane separator, and further comprising separating feed air in the membrane separator to produce gaseous nitrogen.  
   
   
       12 . The method of  claim 10  wherein the gaseous nitrogen is passed continuously over a period of time from the nitrogen source into the insulated vessel.  
   
   
       13 . The method of  claim 12  wherein some gaseous nitrogen is passed out of the insulated vessel during the said period of time.  
   
   
       14 . The method of  claim 12  wherein the flowrate of gaseous nitrogen into the insulated vessel during the said period of time is changed at least once causing a change in the amount of liquid within the insulated vessel.  
   
   
       15 . The method of  claim 10  wherein the liquid nitrogen within the insulated vessel forms a pool and the gaseous nitrogen is passed from the nitrogen source into the pool of liquid nitrogen.  
   
   
       16 . The method of  claim 10  wherein the liquid nitrogen within the insulated vessel forms a pool having a surface, and the gaseous nitrogen is passed from the nitrogen source into the insulted vessel such that it impinges upon the surface of the pool of liquid nitrogen.