Parkhurst & Wendel, L.L.P.
Oxide sensor
 Disclosed is an oxide sensor in which O.sub.2 contained in a measurement gas introduced into a first chamber through a first diffusion rate-determining section is removed by the aid of a pumping voltage applied between pumping electrodes, and then the measurement gas is introduced into a second chamber through a second diffusion rate-determining section to remove excessive O.sub.2 by the aid of auxiliary pumping electrodes. A detecting electrode is arranged to satisfy d.gtoreq.t provided that d represents a distance from an end of the auxiliary pumping electrodes on the side of the second diffusion rate-determining section to an end of the detecting electrode on the side of the second diffusion rate-determining section, and t represents a height of the second chamber. A predetermined pumping voltage is applied to the detecting electrode to decompose oxides contained in the measurement gas by the aid of the detecting electrode or a catalyst. The amount of oxygen produced by the decomposition is measured to determine the concentration of the oxides. Accordingly, the amount of the oxides in the measurement gas can be measured extremely highly accurately without being affected by water and carbon dioxide contained in the measurement gas. 
NGK Insulators, Ltd.
G G
G01N G01N
inventional inventional
Kunihiko Nobuhide
Nakagaki Kato