Platinum-Sheathed High-Temperature Platinum Resistance Thermometers for Use up to 1200°C

摘要

A new type of High-Temperature Platinum Resistance Thermometer (HTPRT) with a platinum sheath was developed. The stability of the resistance at temperatures above 1100°C up to 1170°C was studied. The HTPRTs have shown resistance changes of 1.0 mK/h at 1100°C, 0.7 mK/h at 1150°C and 0.2 mK/h at 1170°C, respectively. The values of W(29.7646°C) after exposure at 1170°C were found to be larger than 1.118 07. This fact may imply that the HTPRTs developed can be used as a standard thermometer in the ITS-90. Application of this HTPRT in a furnace control system produced a significant improvement in temperature control from +-27 mK by a thermocouple to +-0.3 mK by the HTPRT.