Patent ID: 6383354
Filing Date: 2002-05-07
Classification: G01N

Abstract:
A gas concentration sensing apparatus comprising:a gas introducing portion for introducing a measurement gas; a first cell configured and disposed so as to be exposed to the measurement gas introduced via the gas introducing portion and configured to pump oxygen from the measurement gas in the gas introducing portion, the first cell comprising first and second first cell electrodes disposed on opposite sides of a first solid electrolytic layer; a second cell configured and disposed so as to be exposed to the measurement gas introduced via the gas introducing portion and configured to sense a concentration of a specific component of the measurement gas from which oxygen has been pumped by the first cell, the second cell comprising first and second second cell electrodes disposed on opposite sides of a second solid electrolytic layer; a reference gas chamber with respect to which one of the first and second cells is disposed such that the first electrode of said one of the first and second cells is exposed to a reference gas in the reference gas chamber and such that the second electrode of said one of the first and second cells is exposed to the measurement gas introduced via the gas introducing portion; and means for maintaining a voltage at the second electrode of said one of said first and second cells at a level greater than 0 V such that oxygen can be caused to be introduced into the gas introducing portion by means of said one of said first and second cells.