Inert gas purifying system

Claim 1

A combination of electrochemical cells for removing oxygen as an impurity from inert gases, comprising: a first electrochemical cell comprising a cathode chamber having an inlet for oxygen-contaminated inert gas and an outlet for semi-purified inert gas, an anode chamber having an outlet for oxygen gas, a solid, non-porous oxygen ion conducting electrolyte consisting essentially of ceria, a porous cathode coating containing perovskite metal oxides adherent to said electrolyte, a porous anode coating containing perovskite metal oxides adherent to said electrolyte, metallic current collectors adherent to the exposed surface of said cathode and anode; a second electrochemical cell comprising a cathode chamber having an inlet communicating with the outlet for semi-purified gas from the cathode chamber of said first electrochemical cell, said second electrochemical cell cathode chamber having an outlet for purified inert gas, an anode chamber having an outlet for oxygen gas, a solid, non-porous ceramic metal oxide electrolyte separating said cathode chamber from said anode chamber, said electrolyte having a high thermodynamic decomposition potential at elevated temperatures and said metal having only one thermodynamically stable ionic valence state, a porous cathode coating adherent to said electrolyte, said cathode being in said cathode chamber and consisting essentially of an electronically conducting metal, metal-cermet or a "n" type semiconducting oxides, a porous anode coating adherent to said electrolyte, said anode being in said anode chamber and comprising perovskite metal oxide electrode, and metallic current collectors adherent to the exposed surface of said cathode and said anode.