Apparatus and method for rapidly freezing small objects

Abstract

A compact desktop gas liquefaction system having a gas generator, a cooling unit having a Stirling, pulse-tube or Stirling-pulse-tube cooler, and an insulated container to receive the liquefied gas. The system may be used to produce liquid nitrogen, oxygen, argon, natural gas, or air. The insulated container can be quickly disengaged from the gas liquefaction system, thereby minimizing the risk associated with handling liquefied gases. This compact liquefier allows for on-demand and on-site cryogen generation. The system provides a condenser surrounded by an evacuated space for greater efficiency of operation in a limited space.

1 . A gas liquefaction system for producing liquefied gas from a gas, said gas liquefaction system comprising:
 a) a gas generator ( 20 ) for generating the gas;   b) a cooling unit ( 30 ) for liquefying the gas, said cooling unit comprising:
 i) a cooler ( 49 ); 
 ii) a condenser ( 37 ) wherein gas generated by said gas generator is cooled in said condenser sufficiently to liquefy the gas; 
 iii) a vacuum means ( 66 ); and, 
 iv) an evacuation chamber ( 35 ) surrounding said condenser, said evacuation chamber being in communication with said vacuum means, wherein said vacuum means is operative for evacuating said evacuation chamber whereby a vacuum is produced around said condenser; 
   c) a gas inlet ( 21 ,  39 ) in fluid communication with said gas generator and with one of said interior of said container and said cooling unit;   d) a container ( 40 ) for receiving and holding the liquefied gas, said container having an interior ( 55 ); and,   e) a conduit ( 42 ) connecting said cooling unit to said interior of said container.   
   
   
       2 . The gas liquefaction system of  claim 1 , wherein said gas inlet conducts the gas from said gas generator to said interior of said container, whereby said conduit conducts the gas from said interior of said container to said cooling unit and said conduit also conducts the liquefied gas back into said interior of said container. 
   
   
       3 . The gas liquefaction system of  claim 1 , wherein said gas inlet conducts gas from said gas generator to said cooling unit, whereby the gas generated by said gas generator flows through said gas inlet an into said cooling unit and the liquefied gas flows through said conduit and into said interior of said container. 
   
   
       4 . The gas liquefaction system of  claim 3 , wherein said gas inlet is in direct communication with said condenser. 
   
   
       5 . The gas liquefaction system of  claim 1 , wherein said cooling unit is one of a Stirling, a pulse-tube, or a Stirling-pulse-tube cooler. 
   
   
       6 . The gas liquefaction system of  claim 1 , configured to be sufficiently small to be positioned on a desktop. 
   
   
       7 . The liquefaction system of  claim 1 , wherein said cooling unit and said gas generator combined fit within a total volume of no more than approximately 102 liters. 
   
   
       8 . The gas liquefaction system of  claim 1 , wherein said container is coupled to said cooling unit. 
   
   
       9 . The gas liquefaction system of  claim 8 , wherein the coupling of said container to said cooling unit is accomplished by means of an elongated tube ( 61 ) surrounding said conduit and coupled to an orifice ( 62 ) in said cooling unit. 
   
   
       10 . The gas liquefaction system of  claim 9  wherein said elongated tube is sealed to the orifice of said cooling unit by at least one O-ring ( 23 A). 
   
   
       11 . The gas liquefaction system of  claim 8 , wherein said container can be disconnected from and reconnected to said cooling unit by lowering and raising, respectively, said container relative to said cooling unit. 
   
   
       12 . The gas liquefaction system of  claim 1  further comprising:
 a) a platform ( 29 ) for supporting said container;   b) a raising and lowering means ( 28 ,  29 ,  33 ,  57 ) for raising and lowering said platform whereby raising said platform by said raising and lowering means positions said container to be filled, and lowering said platform by said raising and lowering means positions said container to be accessed or removed.   
   
   
       13 . The gas liquefaction system of  claim 1 , further comprising:
 a) a platform ( 29 ) for supporting said container;   b) at least one pivotal arm ( 28 ) connected to said platform wherein said platform is raised and lowered by pivoting said pivotal arm; and,   c) a lever ( 57 ) connected to said pivotal arm for pivoting said pivotal arm in order to raise and lower said platform,   whereby raising said platform positions said container to be filled, and lowering said platform positions said container to be accessed or removed.   
   
   
       14 . The gas liquefaction system of  claim 1 , wherein said container is a handheld container. 
   
   
       15 . The gas liquefaction system of  claim 1 , wherein said gas generator is operative to generate nitrogen gas from air. 
   
   
       16 . The gas liquefaction system of  claim 1 , further comprising an extraction line ( 25 ) in communication with said interior of said container, wherein the liquid gas is extracted from said container through said extraction line without moving said container. 
   
   
       17 . The gas liquefaction system of  claim 16  wherein said extraction line has at least one insulated portion ( 25 C).