| Issue |
2019
19th International Congress of Metrology
|
|
|---|---|---|
| Article Number | 24002 | |
| Number of page(s) | 10 | |
| Section | Standards in Thermal Measurements / Références en Thermique | |
| DOI | https://doi.org/10.1051/metrology/201924002 | |
| Published online | 23 September 2019 | |
Improving fixed-point cell realization by modifying furnace heater shape
1
National Physical Laboratory, Teddington, TW11 0LW, UK
2
Thermo Gauge Instruments Inc, Fort Ashby, WV 26719, USA
* Corresponding author: dave.lowe@npl.co.uk
Recent changes to the SI make it possible to set up a primary temperature scale using established values for certain high-temperature fixed points. As the furnace used with the fixed points can itself have a significant impact on measurements, improving furnace temperature uniformity can help to reduce uncertainties. A thermal model was used to redesign heaters to reduce temperature gradients where the fixed-point cell is positioned in the furnace. A heater optimised for 1325 °C was compared to the standard one with a cobalt carbon high-temperature fixed-point cells, where the cell was installed in the middle, and also moved 10 mm to each end. The modified heater showed reduced melting range, improved plateau run-off and less sensitivity to fixed-point cell position. The improvements will reduce the uncertainties associated with this type of furnace.
© The Authors, published by EDP Sciences, 2019
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.