Process for manufacturing platinum resistance thermometer

Abstract

A process for manufacturing a platinum resistance thermometer that is stable with reduced resistance value variation over service temperature range through clarification of a quantitative mechanism of resistance value variation with respect to the oxidation/reduction of platinum resistance wire. The process including the steps of (S1) enclosing a purge gas containing an inert gas and oxygen in a protection tube provided with a thermosensitive part of platinum resistance wire; (S2) raising the internal temperature of the protection tube to a temperature region in which the platinum is in reduced form at a partial pressure of oxygen in the purge gas as determined from platinum oxide formation free energy; (S3) replacing the purge gas with an inert gas wherein oxygen is 1 kPa or below; and (S4) sealing the protection tube under the replaced condition.

Dependencies are inferred from the claim text.