An Investigation into the Stability of Industrial Platinum Resistance Thermometers

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An Investigation into the Stability of Industrial Platinum Resistance Thermometers (262.44 KB)

The stabilities of more than 20 industrial platinum resistance thermometer (IPRT) elements from four manufactures were investigated. All elements were assembled into probes with a sheath, and the assembly technique was found to be important to stability and accuracy. A set of apparatus was set up for the investigation. The test results with different sheathing materials and assembly techniques are compared. Drift rates as low as 0.002°C per 100 hours at 650°C were achieved. Two vital characteristics, thermal hysteresis and dielectric effect, were tested and are discussed in detail. Further improvements to the stability and accuracy of assembled IPRTs are discussed.