Parkhurst & Wendel
Gas sensor
 Disclosed is a gas sensor comprising inner pumping electrodes arranged on upper and lower surfaces and both side surfaces in a first chamber so that O.sub.2 contained in a measurement gas introduced through a first diffusion rate-determining section is effectively removed by the aid of a pumping voltage applied between the inner pumping electrodes and an outer pumping electrode. After the removal of O.sub.2, the measurement gas is introduced into a second chamber through a second diffusion rate-determining section so that oxides contained in the measurement gas are decomposed by the aid of a detecting electrode, or O.sub.2 is bound to inflammable gases contained in the measurement gas. An amount of oxygen moved or transported in accordance therewith is measured to determine the concentration of the oxides or the inflammable gases. Accordingly, the oxygen contained in the measurement gas can be effectively controlled, making it possible to highly accurately measure the oxides or the inflammable gases. 
NGK Insulators, Ltd.
G G
G01N G01N
inventional inventional
Kunihiko Nobuhide
Nakagaki Kato