Parkhurst, Wendel & Rossi
Waterproof type oxygen sensor
 An oxygen sensor for measuring an oxygen concentration in exhaust gases discharged from an automobile including an oxygen sensing element having inner and outer electrodes which communicate with the atmospheric air serving as a reference oxygen and the exhaust gases, and a tube-like metal cap in which the sensing element is arranged. Within a space formed between the sensing element and the metal cap are arranged first and second compressed talc members serving as gas-tight sealing sections to constitute a first space which is isolated from the exhaust gases by means of the first and second talc members and a second space which is isolated from the exhaust gases by means of the second talc member. In the metal cap is formed an opening which is communicated with the second space, so that a very small amount of the exhaust gases which might be introduced into the second space is discharged through the opening and is effectively prevented from being further introduced into the first space via the first talc member. The first space is communicated on one hand with a reference gas space into which the inner electrode of the sensing element is exposed and on the other hand with the surrounding atmospheric air by means of an air introducing section which is constructed to pass the air but does not allow passage of water therethrough. 
NGK Insulators, Ltd.
G
G01N
inventional
Nobuhide Masanori
Kato Katsu