PURPOSE: To produce gaseous nitrogen of desired purity by detecting the concn. of oxygen in gaseous nitrogen taken out through a cathode in an electrochemical cell and by controlling voltage impressed to the cell in accordance with the concn. of oxygen.
CONSTITUTION: A fixed volume of air is fed into an electrochemical cell 1 from a feeding inlet 12, and direct current is supplied between a cathode terminal plate 9 and an anode terminal plate 10 from a controller 3. Nitrogen is taken out of an outlet 15 through a chamber 2 for detecting the concn. of oxygen, and oxygen is exhausted from an exhausting outlet 14. The chamber 2 is provided with a galvanic cell type oxygen sensor, and the sensor detects the concn. of oxygen in nitrogen taken out through the chamber 2 and sends the signal to the controller 3. When the concn. of oxygen is higher than a prescribed value, the controller 3 increases voltage impressed to the cell 1 or electric current supplied to the cell 1. When the concn. of oxygen is lower than the prescribed vallue, the controller 3 reduces the voltage of electric current. Thus, the purity of nitrogen taken out of the outlet 15 is made constant.
KUDOU HISASHI
TANIGAWA IKUO
| JPS5525343A | 1980-02-23 |
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