Blackbody comparator for thermocouple calibration

M. Ojanen, O.M. Hahtela, M. Heinonen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

2 Citations (Scopus)


MIKES is developing a measurement set-up for calibrating thermocouples in the temperature range 960°C-1500°C. The calibration method is based on direct comparison of thermocouples and radiation thermometers. We have designed a graphite blackbody comparator cell, which is operated in a horizontal single-zone tube furnace. The cell includes two blackbody cavities for radiation temperature measurements. The cavities have openings on opposite sides of the cell, allowing simultaneous measurement with two radiation thermometers. The design of the comparator allows three thermocouples to be calibrated simultaneously. The thermocouples to be calibrated are inserted in thermometer wells around one of the measurement cavities. We characterize the blackbody comparator in terms of repeatability, temperature distribution and emissivity. Finally, we validate the uncertainty analysis by comparing calibration results obtained for type B and S thermocouples to the calibration results reported by Technical Research Institute of Sweden (SP), and MIKES. The agreement in the temperature range 1000°C-1500°C is within 0.90°C, the average deviation being 0.17°C.
Original languageEnglish
Title of host publicationTemperature: Its Measurement and Control in Science and Industry
Subtitle of host publicationProceedings of the Ninth International Temperature Symposium
EditorsChristopher W. Meyer
PublisherAmerican Institute of Physics (AIP)
ISBN (Print)978-0-7354-1178-4
Publication statusPublished - 2013
MoE publication typeA4 Article in a conference publication
Event9th International Temperature Symposium, ITS9 - Los Angeles, CA, United States
Duration: 19 Mar 201223 Mar 2012

Publication series

SeriesAIP Conference Proceedings


Conference9th International Temperature Symposium, ITS9
Abbreviated titleITS9
Country/TerritoryUnited States
CityLos Angeles, CA


  • thermocouples
  • calibration
  • comparators
  • thermometers
  • emissivity


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