Study On The Performance Of On-site Comparator Based On Miniature Temperature Fixed Points

With the development and increased demand of flatness of value transmission,the precision of on-site calibration has been brought to more attention in the relevant industry.Therefore,in response to the specific demand for precise calibration of platinum resistance thermometers in industrial sites,this paper explores the development of the field comparator based on the miniature phase change fixed point technology through experimental and theoretical analysis of the phase change characteristics of miniature single and double temperature fixed points,and eventually providing the technical support for industrial field temperature measurement calibration.The details are as follows:(1)This paper starts from the development of two miniature temperature fixed points.To be more specific,the first type-a Ga metal single-temperature fixed point.And following with the second type-a miniature dual-temperature fixed point device(a miniature Ga、In fixed point and a miniature In、Sn fixed point),which is designed based on the first type.Through experiments,the reproducibility of the W value of micro-Ga fixed point is less than 2m K.The temperature repeatability of the two miniature dual temperature fixed points are better than 7m K.The technical indicators are higher than the requirements of industrial calibration and fully meet the needs of industrial field temperature measurement.(2)Then,this paper discusses the development of a miniature fixed point on-site comparator.The operating temperature range of the comparator is 0°C～200°C and the temperature control accuracy is 0.1.Experimental research proves that the vertical temperature field of the device is less than 0.05°C and the stability is ±0.0023°C/30 min.(3)In order to deepen the understanding of the phase transition process and improve the performance of the temperature fixed point,we use numerical calculation methods to study the miniature temperature fixed point phase transition process.By analyzing the effects of different temperature differences and different heating rates on the temperature plateau,we determined the optimal temperature difference and heating rate.Furthermore,we simulated the phase transition process of the miniature dualtemperature fixed point and compared with experimental measurement data of the simulation results of dual-temperature fixed points.The simulation results are in agreement with the experimental results,which explains the experimental phenomenon that the micro-fixed point phase transition temperature is higher than the standard value.The conclusions of this paper can provide a reference for the design and research of miniature temperature fixed points,as well as a reference for the research of industrial field thermometer calibration.