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US 5,635,044 AGranted
Electrode for zirconia oxygen sensors
OwnerThomas H. Lotze, William Thompson +1inventors
InventorsThomas H. Lotze, William Thompson, Theodore P. Berry
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Abstract
An oxygen sensor is provided with a virtual point contact electrode to improve performance, extend operational life and to minimize thermal shock breakage; it is also provided with reduced annular space between the protective sheath and zirconia electrolyte, and minimized communicating openings to the furnace atmosphere, in order to reduce burnoff air flow during probe conditioning.
Claims8
An oxygen sensor for measuring gas composition in a heat treating furnace, said oxygen sensor comprising:
- a tubular ceramic electrolyte with a convex end closure,
- said electrolyte having a tip with an inner reference surface connected to a reference electrode and an outer sensing surface in contact with a sensing electrode,
- said sensing electrode in substantially point contact with said outer sensing surface at said tip of said electrolyte at a point of tangency,
- said sensing electrode connected to a protective sheath that has an annular side wall which is spaced apart from and surrounds said electrolyte,
- a conductor means for transmitting a generated voltage from said electrodes to a measuring device,
- a plurality of communicating holes in said side wall of said sheath close to said tip of said electrolyte,
- said outer sensing surface is convex,
- said sensing electrode has a concave electrolyte contacting surface with a centrally located point contact region where said outer sensing surface of said electrolyte and said electrolyte contacting surface of said sensing electrode meet at said point of tangency, and
- said electrolyte contacting surface has a first radius of curvature greater than a second radius of curvature of said outer sensing surface of said electrolyte at said point of tangency.
6 more elements
Dependencies are inferred from the claim text.