Oxygen sensor

An oxygen sensor for determining an oxygen partial pressure for a measurement gas in a measurement-gas space, comprising:

• an elongate planar oxygen sensing element with an outer peripheral portion, having an oxygen detecting portion adjacent to a first longitudinal end thereof, and electrical terminal means adjacent to a second longitudinal end thereof, said electrical terminal means comprises a plug including at least one pair of electrical contacts which are exposed on a surface of said planar oxygen sensing element;
• connector means disposed adjacent to said electrical terminal means, said connector means including electrical connectors which are held in direct electrical contact with said electrical terminal means, said electrical connectors comprising a resilient material and being held in a resilient pressed electrical contact with said at least one pair of electrical contacts of the electrical terminal means;
• tubular protective means having an inner surface and an outer surface for accommodating and protecting said oxygen sensing element therein, said tubular protective means comprising a first protective covering portion for protecting at least an end portion of said sensing elment which is located within said measurement-gas space and exposed to said measurement gas and which includes said oxygen detecting portion, said tubular protective means further comprising a second protective covering portion covering a remaining portion of said sensing element which is not exposed to said measurement gas;
• a retainer housing for attaching said tubular protective means to a partition wall defining said measurementgas space, said elongate planar oxygen sensing element having a length of at least 40 mm as measured from said partition wall to said second longitudinal end;
• and
• at least two air-tight masses of an inorganic particulate material which fill in at least portions of a space defined between the outer peripheral portion of the oxygen sensing element and the inner surface of the tubular protective means, said at least two air-tight masses being spaced apart from each other along a longitudinal axis of the tubular protective means, one of said at least two air-tight masses being located adjacent to said retainer housing and a second one of said at least two air-tight masses being located between said electrical terminal means and said one air-tight mass.