Temperature is one of the most important parameters that are often required to be measured. Thermocouples are & have been the main temperature sensor used in industry for over 100 years, particularly in the temperature range above 500 ˚C.
The problem with thermocouples is that they are often exposed to harsh conditions during use. This causes them to suffer from drift, a change in an output signal with time at temperature. This eventually leads to inaccurate measurement.
Current methods used to deal with drift in thermocouples range from, replacement at regular intervals, removal for re-calibration & on-location calibration. This is because the rate of thermocouple drift is difficult to predict. All these methods work but result in furnace downtime, additional labour & calibration costs.
Is there a Thermocouple drift solution?
Originally developed by the National Physical Laboratory (NPL) as a key objective of the EMPRESS Project, the INSEVA technology is a miniaturised version of the conventional fixed-point cells used in thermal calibration laboratories for the highest level of calibration. The INSEVA can provide validation of the thermocouple readings from within the furnace, confirming the true furnace temperature. This means the sensor can validate the furnace compliance when regularly replacing the sensor or re-calibrating is impractical.
What is fixed-point calibration?
A fixed point is a reproducible physical event that has a defined temperature value assigned on the ITS90. The reliable melting/freezing point of pure metal & more recently metal carbide eutectics are used to calibrate thermocouples at set fixed point temperatures. An example of a conventional fixed point used in temperature calibrations is Copper, which melts (goes through the transition from a solid to a liquid) at exactly 1084.62 °C. Under these conditions, the tightest of uncertainties of measurement & accuracies possible can be achieved for temperature sensor calibration.
With an outer diameter of just 4 mm, the miniaturised fixed-point cell can fit in a typical 7 mm outer diameter alumina insulated ceramic thermocouple assembly.
Just like a regular thermocouple assembly, the INSEVA Thermocouple can be highly customised with alternative cold end termination options such as; tails, plugs, sockets & cables. Additional stainless steel outer sheaths can also be added for protection from the hostile environments they encounter. The miniaturised cell can contain any stable pure metal or metal carbide eutectics, making the INSEVA highly customisable to fit the specific requirements of the end-user.
Developed in-house by our software team, the INSEVA software detects the voltage reading hesitation (or plateau) of the thermocouple as the thermal environment transits the melt/freeze point of the chosen cell material & triggers customer bespoke automation.
The software provides real-time information to monitor the calibration status of the INSEVA Thermocouple, enables predictive replacement & automates control of thermocouple life.
The INSEVA Thermocouple is set to alter how the industry uses temperature sensors & bring the dated techniques of manufacturing into the 21st century & beyond. With industry trails currently ongoing, the INSEVA is looking at launching in 2022.
Check out the introduction video above, or for more information on the INSEVA, contact us.
CCPI Europe was founded in 1984 on the outskirts of Sheffield, United Kingdom – known famously as “The Steel City” thanks to its global reputation for steel production during the industrial revolution.
With over 35 years of industry experience, we are the experts in the field of manufacturing and calibration of temperature sensors, working in partnership with our customers to ensure we don’t just meet but exceed their expectations.
NPL is the UK’s National Metrology Institute, developing and maintaining the national primary measurement standards. It is a Public Corporation owned by the Department of Business, Energy and Industrial Strategy (BEIS). It has a partnering agreement with BEIS and the University of Strathclyde and the University of Surrey. NPL is part of the National Measurement System (NMS) which provides the UK with a national measurement infrastructure and delivers the UK Measurement Strategy on behalf of BEIS.
A three-year project coordinated by the National Physical Laboratory (NPL) and funded by the European Association of National Metrology Institutes (EURAMET) to look at enhancing process efficiency through improved temperature measurement (EMPRESS).