|  1/00  | Processes or apparatus for liquefying or solidifying gases or gaseous mixtures | 
|  1/02  | Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen | 
|  3/00  | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification | 
|  3/02  | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream (F25J 3/08 takes precedence) | 
|  3/04  | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification by rectification, i.e. by continuous interchange of heat and material between a vapour stream and a liquid stream (F25J 3/08 takes precedence) for air | 
|  3/06  | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification by partial condensation (F25J 3/08 takes precedence; by rectification F25J 3/02) | 
|  3/08  | Processes or apparatus for separating the constituents of gaseous mixtures involving the use of liquefaction or solidification Separating gaseous impurities from gases or gaseous mixtures (cold traps B01D 8/00) | 
|  5/00  | Arrangements of cold-exchangers or cold-accumulators in separation or liquefaction plants (heat-exchangers F28C, F28D, F28F) |