The industry need in this field lies in assuring and improving the quality of products, maximising process efficiency and optimising energy management for processes operating in the range from 232 °C to 1100 °C. Thermocouple performance is critically dependent upon uniformity of physical and chemical properties along the length of the thermoelement. With use, thermocouples lose homogeneity through heat, chemical exposure, or mechanical damage, causing the measured voltage to differ at the same temperature, resulting in error and severely reducing the temperature measurement accuracy.
The overall objective of the project is to develop novel methods and techniques that will significantly improve knowledge and facilities that will provide confidence in the verification of thermocouple performance and improving temperature measurement and control capability. The project will contribute to establishing low measurement uncertainty and reproducible process control in Europe.
The specific scientific and technical objectives of this project are:
- To develop and test novel methods and devices for the monitoring of thermocouple drift in-situ in the temperature range up to 1100 °C. These methods have to be suitable for implementation in critical industrial processes in order to assist the users in maintenance and replacement decisions.
- To develop and test easy-to-operate methods and instruments for the assessment of inhomogeneities of thermocouples for secondary calibration laboratories in the temperature range from 230 °C to 1100 °C.
- To design and construct novel measurement facilities that can provide confidence in the verification of thermocouple performance and to identify and quantify the range of drift of the thermocouples. The new facilities, targeting primary calibration laboratories, should have the ability to measure the physical changes and behaviour of thermocouples under typical conditions of production and distribution processes with a target uncertainty of less than 1.5 °C.
- For each participant, to develop an individual strategy for the long-term operation of the capacity developed, including regulatory support, research collaborations, quality schemes and accreditation. They will also develop a strategy for offering calibration services from the established facilities to their own country and neighbouring countries. The individual strategies will be discussed within the consortium, with other EURAMET NMIs/DIs and with a broad spectrum of stakeholders, through questionnaires and workshops organised in the local language. The individual strategies will lead to an overall strategy document to be presented to the EURAMET TC-T, to ensure that a coordinated and optimised approach to the development of traceability in this field is developed for Europe as a whole.
Progress beyond the state of the art
At all levels of the traceability chain, from final user to the primary laboratory there is a lack of both methods and devices for thermocouple performance metrics.
Novel devices and methods that will enable the partners and stakeholders to monitor the drift of their thermocouples in-situ will be developed, manufactured and tested.
The project will develop competence and capacity at each of the participant emerging NMIs/DIs for primary and secondary level metrological characterisation of base metal and platinum based thermocouples and establish validated procedures and measurement capabilities that are needed for the comprehensive study of the parameters that cause changes in thermocouples leading to inhomogeneity and drift.
The miniature fixed point cells will be combined with a newly developed phase-ratio sensing device and a Curie-point device suitable for drift, stability and inhomogeneity tests of thermocouples by providing longer lasting fixed-point plateaux.
The project builds research capacity at each of the emerging NMIs/DIs through collaboration and dissemination of knowledge between partners, including practical hands-on training delivered by experts from developed NMIs/DIs.
All of the participants from the emerging countries will develop a strategy for offering calibration services from the established facilities to their own country and neighbouring countries, in accordance with their needs.
This project will have an impact on a wide range of industries where temperature measurement and control are vitally important, as well as on healthcare, climate change and global warming monitoring. Control of temperature is critical to many industrial processes, yet the relevant sensors require regular calibration.