Improved High-Temperature Standard Platinum Resistance Thermometer

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Improved High-Temperature Standard Platinum Resistance Thermometer (360.89 KB)

To prevent short circuits, to improve stability, and to raise the upper temperature limit to the freezing point of copper (1084.62 ◦C), the high-temperature standard platinum resistance thermometer (HTSPRT) was redesigned. The most important change was an improvement in the structure of the sensor support. The strip support was replaced by a new specially designed cross support. The structure and design of the new HTSPRT are briefly described in this article. The test results of a group of thermometers are presented. The test included long-term drifts of the thermometers at the triple point of water and freezing point of silver during a period of a few hundred hours operation at 1085 ◦C, the short-term stability of R (tpw) and W (Ag) in a period of 5 days, and thermal cycles between 22 ◦C and 1085 ◦C. The test results show that the thermometer performance is improved, and the new HTSPRT can operate up to the freezing point of copper.