SUSU scientists are developing new measurement circuits and methods for diagnostics of the quality of operation of a temperature gauge – thermoelectric transducer (thermocouple). This development can find application in petrochemical industry, mechanical engineering, metallurgy, and electric power engineering. It will allow to improve the accuracy of temperature measurement using thermocouples and will ensure the safety of production processes thanks to early detection of thermocouples' failure.
This project is being fulfilled within the Priority 2030 program and is part of the Intelligent Manufacturing strategic project. In 2023 SUSU scientists have already obtained a patent for invention for a "Method of Determining the Veracity of Measurement Results Using a Thermoelectric Transducer".
The existing approaches to determining the veracity of measurements using thermocouples have a number of drawbacks. Some of them are expensive and take much time to complete (more than 4 hours), and others are characterized with high level of detected error (±10℃) and susceptibility to influence from external factors.
Using of the new measurement circuit created by the SUSU scientists will reduce the time of thermocouple diagnostics to 1-2 minutes, and the minimal estimated value of error will be ± 2℃. The approach to diagnostics of the accuracy of thermocouples measurement, that is being developed, is not susceptible to influence from technological processes inside which the thermocouple is operating.
The approach being proposed by the research fellows of the SUSU School of Electronic Engineering and Computer Science implies uniting several thermocouple conductors made of different materials. Thus, the new thermocouple measurement circuit is a multielectrode structure. Thanks to such solution, the scientists will be able to obtain more data on the parameters being measured, and this will improve the accuracy of the research.
"We are developing new measurement circuits for one-zone (temperature measurement in one point) and multi-zone (temperature measurement in several points) thermocouples. The obtained additional information on the device's functioning allows the temperature gauges to complete metrological self-validation. The metrological monitoring is the capability of a gauge to independently track the increase in its error and report to the user if the error exceeds the admissible limits," shares Ivan Fedosov, junior research fellow at the Research Laboratory for Self-Validating Sensors, Systems, and Advanced Instrumentation.
Processing of the obtained measurements information allows to form the status of the measurement results, which characterizes the increase in the value of the thermocouple error as compared to the admissible level.
"For example, a standard thermocouple simply measures the temperature and yields only one value as a result. And we do not know how high the error of this value is, whether it is still within the admissible limit, or has already increased significantly. Our solution will allow to display the result with not only the temperature value, but with the measurement status as well. For instance, there can be a system of 3 statuses: "confirmed" – all is well, the error being within the permissible limit; "warning" – the error is increasing, but the thermocouple can still be used; "not valid" – the obtained measurement result has a significant error, and the thermocouple must be replaced," explains the scientist.
The technology of thermocouples' metrological self-validation will allow to improve the quality of the manufactured products thanks to a more strict temperature control (reducing the process temperature deviation from the rated temperature by 2-5 times), as well as will make technological processes safer. Temperature gauges of thermocouples are used in vacuum furnaces, blast furnaces, rolling mills, autoclaves, as part of the equipment for diagnostics of electric drives, and so on.
At the next stage of the work, the scientists are planning on designing prototypes of smart temperature gauges for thermoelectric transducer. The gauges will have a new measurement circuit and will be capable of implementing the methods of status determining and correcting the measurement results. The developed solutions will be tested at the sites of industrial partners (Magnitogorsk Iron & Steel Works, United Engine Corporation, and Fortum company). Within the process of working on the topic of this research it is planned to file 2 more applications for invention patenting.
The results of this work will be published in top-rated journals, such as Measurement Science and Technology (Q2), Measurement (Q1), and IEEE Transactions on Instrumentations and Measurement (TOP 10).
South Ural State University is a university of transformations, where innovative research is conducted in most of the priority fields of science and technology development. In accordance with the strategy of scientific and technological development of the Russian Federation, the university is focused on the development of big scientific interdisciplinary projects in the field of digital industry, materials science, and ecology. In 2021 SUSU became the winner in the competition under the Priority 2030 program. The university acts as a regional project office of the World-class Ural Interregional Research and Education Centre (UIREC), which is aimed at solving the tasks of the Science and Universities National Project.