Arnold, White & Durkee
Heater-built-in oxygen sensor
 A heater-built-in oxygen sensor having an electrochemical cell, a reservoir formed in substantial communication with a reference electrode of the cell, an electrically insulating member held in communication with the reservoir, a heating element disposed in contact with the insulating member, and cooperating with the cell and insulating member to constitute a major portion of an oxygen sensing element, and a direct current power source which is located outside the sensing element and to which the heating element is electrically connected. The low-potential portion of the sensing element connected to the negative terminal of the power source is electrically connected to a measuring electrode of the cell, so that a leak current of at least 0.1 microampere flows from the high-potential portion of the heating element connected to the positive terminal of the power source, to the insulating member through the insulating layer, at an elevated operating temperature of the sensing element, whereby oxygen is pumped from the external measurement gas to which the measuring electrode is exposed, into the reservoir as a reference gas to which the reference electrode is exposed. The reservoir may be defined by a porous structure of the insulating member. 
NGK Insulators, Ltd.
G G
G01N G01N
inventional inventional
Nobuhide Yasuhiko
Kato Hamada