Method for the fractionation of air

Claim 1

IN THE CONTINUOUS FRACTIONATING OF AIR INTO COMPONENTS IN WHICH COMPRESSED AIR INCLUDING CONGEALABLE IMPURITIES IS REFRIGERATED BY HEAT INTERCHANGE WITH COLD PRODUCT GAS AND SUPPLIED TO A FRACTIONATING OPERATION INCLUDING A HIGH PRESSURE SEPARATION ZONE AND A LOW PRESSURE SEPARATION ZONE, DURING ONE PERIOD OF THE HEAT INTERCHANGE COMPRESSED AIR NEAR AMBIENT TEMPERATURE BEING PASSED IN ONE DIRECTION THROUGH A FIRST PATH IN HEAT EXCHANGE EFFECTING RELATIONSHIP WITH COLD PRODUCT GAS TO COOL THE COMPRESSED AIR TO A TEMPERATURE BELOW THE SOLIDIFICATION TEMPERATURE OF THE CONGEALABLE IMPURITIES SO THAT CONGEALABLE IMPURITIES ARE REMOVED FROM THE COMPRESSED AIR AND DEPOSITED IN THE COLDER PORTION OF THE FIRST PATH, DURING ANOTHER PERIOD OF THE HEAT INTERCHANGE THE COMPRESSED AIR BEING PASSED IN THE ONE DIRECTION THROUGH A SECOND PATH AND A STREAM OF SWEEPING COLD PRODUCT GAS BEING PASSED IN THE OPPOSITE DIRECTION THROUGH THE FIRST PATH, THE DIFFERENCE IN THE SPECIFIC HEAT OF THE COMPRESSED AIR AND THE SPECIFIC HEAT OF PRODUCT GAS IN HEAT EXCHANGE EFFECTING RELATIONSHIP THEREWITH PROGRESSIVELY INCREASING ALONG THE HEAT INTERCHANGE IN THE DIRECTION OF AIR FLOW SO THAT WITH EQUAL MASSES OF COMPRESSED AIR AND COLD PRODUCE IN HEAT EXCHANGE EFFECTING RELATIONSHIP THEREWITH THE CONGEALABLE IMPURITIES DEPOSITED IN THE FIRST PATH WOULD NOT BE COMPLETELY SUBLIMED BY THE STREAM OF SWEEPING COLD PRODUCT GAS FLOWING THROUGH THE FIRST PATH, THE METHOD COMPRISING WITHDRAWING COLD HIGH PRESSURE NITROGEN COMPONENT GAS FROM THE HIGH PRESSURE SEPARATION ZONE, PASSING WITHDRAWN HIGH PRESSURE NITROGEN COMPONENT GAS SUBSTANTIALLY AT THE HIGH PRESSURE THROUGH A SUPPLEMENTAL PATH IN AN OPPOSITE DIRECTION TO THAT OF THE COMPRESSED AIR IN THE FIRST PATH, THE SUPPLEMENTAL THE COMPRESSED AIR IN THE FIRST PATH, THE SUPPLEMENTAL AT LEAST THE COLDER PORTION OF THE FIRST PATH, EXPANDING WARMED HIGH PRESSURE NITROGEN COMPONENT GAS FROM THE SUPPLEMENTAL PATH, AND ADDING EXPANDED NITROGEN GAS TO COLD NITROGEN COMPONENT GAS FLOWING TO THE HEAT INTERCHANGE, THE MASS OF THE HIGH PRESSURE NITROGEN COMPONENT GAS PASSING THROUGH THE SUPPLEMENTAL PATH BEING CONTROLLED SO AS TO CONSTITUTE THE SOLE MEDIUM FOR COMPENSATING FOR SAID DIFFERENCE IN SPECIFIC HEATS TO THE EXTENT NECESSARY TO REDUCE THE TEMPERATURE DIFFERENCE OF THE COMPRESSED AIR AND THE STREAM OF SWEEPING COLD PRODUCT GAS AT THE COLD END OF THE HEAT INTERCHANGE TO 5*C. OR LESS, WHEREBY THE STREAM OF SWEEPING COLD PRODUCT GAS FLOWING THROUGH THE FIRST PATH SUBSTANTIALLY COMPLETELY SUBLIMES THE DEPOSITED CONGEALABLE IMPURITIES.