Abstract:According to IEC 60751 and ASTM E644-11 international standards, we study the thermal hysteresis of quartz crystal type, platinum resistance type and thermistor type seismic water temperature observation instruments in the temperature ranges of 0 ℃ to 100 ℃, 0 ℃ to 70 ℃ and 0 ℃ to 50 ℃, and define the heat leakage effect of local immersion calibration. Further, we analyze the contribution of both to measurement uncertainty, and identify the instrument drift characteristics. The results show that the thermal hysteresis of thermometer reduces with the decrease of measuring point temperature, and the maximum value is 0.025 5 ℃(platinum resistance type, 50 ℃ measuring point). At the same temperature point, the thermal hysteresis of quartz crystal type thermometer is less than that of platinum resistance and thermistor types. When the local immersion method is used for calibration, the immersion depth of temperature sensing element should not be less than 30 cm, and the maximum heat leakage effect is about 0.01 ℃(100 ℃ measuring point). The thermal hysteresis component contributes the most to measurement uncertainty of platinum resistance thermometer(about 60.7%), and quartz crystal thermometer shows the best measurement accuracy. The measurement results of instrument drift for different sensor types are close, with a range of only 0.000 3 ℃/24 h. In the future, the instrument stability can be improved, and the heat leakage effect can be reduced, by replacing the temperature sensing element, optimizing the design, upgrading the process, using a large depth constant temperature bath, heat preservation device and modifying formula.
MING Xiaoran,TIAN Xingyu,WANG Zhongbiao et al. Experimental Study on Thermal Hysteresis, Heat Leakage Effect, and Instrument Drift of Seismic Water Temperature Observation Instruments[J]. jgg, 2024, 44(7): 764-770.