Stability of High Temperature Standard Platinum Resistance Thermometers at High Temperatures

Article English OPEN
  • Publisher: IFSA Publishing, S.L.
  • Journal: Sensors & Transducers (issn: 2306-8515, eissn: 1726-5479)
  • Subject: HTSPRT | Melting point of gallium | Triple point of water | Technology (General) | T1-995

An investigation of the stability of high temperature standard platinum resistance thermometers HTSPRTs has been carried out for two different designs thermometers (with nominal resistance 0.25 Ω and 2.5 Ω) from two different suppliers. The thermometers were heated for more than 160 hours at temperatures above 960 0C using a vertical furnace with a ceramic block. A study was made of the influence of the heat treatment on the stability of the resistance at the triple point of water, and on the relative resistance W(Ga) at the melting point of gallium. The thermometers showed a correlation between the drift note and the values of W(Ga). It was found also that the HTSPRT which has a sensor with strip shaped support and low nominal resistance is more stable than the HTSPRT which has a sensor in the form of a coil wound on silica cross. The 0.25 Ω thermometer has better stability @ 7x10-6 0C (at TPW) after 40 hour. Factors affecting the stability and accuracy of HTSPRT also will be discussed.
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