Oxygen analyzer

A device for analyzing the oxygen content in a sample, comprising:

• a closed gas flow path including a carrier gas inlet port, a vacuum formation port and a sample-introducing port for introducing a sample into said closed gas flow path;
• a pump for circulating a carrier gas along said closed gas flow path;
• an electrochemical oxygen pump for pumping oxygen from said closed gas flow by utilizing a solid electrolyte, said oxygen pump including:
• a heating furnace,
• a cylindrical solid electrolyte, comprising a zirconia material stabilized with one oxide selected from the group consisting of 5-5 mol % of calcium oxide, 6-10 mol % magnesia, and 4-12 mol % yttria housed in said heating furnace, and
• porous electrodes provided inside and outside of said solid electrolyte;
• said circulation pump and said electrochemical oxygen pump being provided in series in said closed gas flow path;
• a sample-melting furnace provided surrounding said closed gas flow path downstream of said sample-introducing port and upstream of said oxygen pump, said sample melting furnace including:
• a sample-melting chamber, and
• a heating furnace;
• a set of lead wires connected to said oxygen pump;
• means for applying a direct current voltage connected to said lead wires;
• means, connected to said lead wires, for measuring a quantity of electricity necessary for pumping oxygen from said closed gas flow path;
• means, provided so as to surround said closed gas flow path downstream of said sample-melting furnace and upstream of said oxygen pump, for cooling gas flowing in said closed gas flow path;
• and
• a filter provided in said closed gas flow path downstream of said cooling means and upstream of said oxygen pump.