Effects of Heat Treatment on the Inhomogeneity of the Pt/Pd Thermocouple at the Cu Freezing Point

Ogura, H.; Numajiri, Haruhiko; Yamazawa, K.; Tamba, J.; Izuchi, M.; Arai, M.

doi:10.1063/1.1627173

Cited by 3 publications

(1 citation statement)

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“…At this point, a furnace anneal was performed to remove physical defects introduced during assembly and to improve the stability and thermoelectric homogeneity of the thermoelements. The annealing was performed for 3 h at a temperature of 1100 • C, followed by 100 h at 1030 • C, which, as previous measurements have shown, yields the smallest drift and inhomogeneity at the Cu fixed point [16]. The annealing was performed over a length of 1000 mm from the measuring junction in a horizontal tube furnace whose temperature uniformity was about ±2 • C over the 1000 mm length.…”

Section: Thermocouple Preparationmentioning

confidence: 99%

Evaluation of the Pd–C eutectic fixed point and the Pt/Pd thermocouple

et al. 2009

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A Pd–C eutectic fixed point cell (1492 °C) was constructed to investigate its utility for thermocouple calibration. The primary aim of the study was to evaluate the long-term stability, immersion characteristics (influence of heat conduction along the thermocouple stem) and robustness of a Pd–C fixed point using a Pt/Pd thermocouple, especially constructed for this purpose. The performance of both devices at this relatively high temperature could therefore be tested. The melting and freezing plateaux at the Pd–C eutectic point were measured using the Pt/Pd thermocouple. The total exposure to the Pd–C melting temperature was about 850 h for the fixed point cell and 550 h for the thermocouple. The standard deviations of the melting and freezing points were 1.03 µV (0.041 °C) and 0.77 µV (0.031 °C) respectively. The emfs of the thermocouple at the melting point were observed to drift by about 0.1 °C. The immersion measurements show that for the current cell design, the measuring junction should be at most 30 mm from the bottom of the thermowell to be properly immersed. The long-term performance and robustness of the fixed point indicate a promising future for its use as a fixed point for calibration of noble metal thermocouples.

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Section: Thermocouple Preparationmentioning

confidence: 99%

Evaluation of the Pd–C eutectic fixed point and the Pt/Pd thermocouple

et al. 2009

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Improving the reliability of temperature measurements up to 1550 °C

Arai¹,

Ogura²,

Izuchi³

2010

Synthesiology English edition

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Since late 1990's, the reliability of temperature measurements at high temperatures was remarkably upgraded by establishing the national measurement standards for calibration of thermocouples up to 1550 °C, and by implementing the traceability system. The traceability system, structured as a hierarchical link of calibrations between the national measurement standards and practical measurements, was designed in consideration of various elements such as availability of the measurement standards and sharing the responsibility with accredited calibration laboratories. The optimized scheme for industries in Japan was established by promoting a balanced combination of conventional techniques held by accredited calibration laboratories and progressive technology, taking into account the spread of the progressive technology.Improving the reliability of temperature measurements up to 1550 °C

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Uncertainty Evaluation on the Freezing Point of Copper for Calibration of Thermocouples

Ogura

Numajiri

Yamazawa

et al. 2003

T. SICE

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A copper freezing-point furnace and four copper freezing-point cells were constructed in our institute. The furnace was consisted of one main heater and two end-heaters. The copper freezing-point cells were open type cells with high-purity graphite crucibles that contained copper of 99.9999% purity. The uncertainty in realizing freezing-point for thermocouple calibration was evaluated using the Pt/Pd thermocouples. The main sources of the uncertainty investigated were reproducibility of the plateau, the temperature distribution in the cell and the impurity effect of the metal. The combined standard uncertainty was estimated to be 20.2mK.

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Effects of Heat Treatment on the Inhomogeneity of the Pt/Pd Thermocouple at the Cu Freezing Point

Cited by 3 publications

References 0 publications

Evaluation of the Pd–C eutectic fixed point and the Pt/Pd thermocouple

Evaluation of the Pd–C eutectic fixed point and the Pt/Pd thermocouple

Improving the reliability of temperature measurements up to 1550 °C

Uncertainty Evaluation on the Freezing Point of Copper for Calibration of Thermocouples

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