* A design of a MoSi2 resistance thermometer, several designs have been tested. So far none of the thermometers have survived the high temperatures. Surprisingly, present thermometers appeared not to survive treatments that are similar as in the earlier project where such treatments were survived. Hypothesis on the cause of this failure based upon comparison of conditions in the earlier project and in this project, the thermometers design was amended and at present (time of writing this T.I.P.) such thermometers are being tested.
* A durable, strategic co-operation of several partners in Europe Several designs have been tested but did not survive the required pre-use heat treatment. The partners representing the industrial users of the thermometers could not test a thermometer. This project could therefore not lead to the co-operation that was envisaged in the project plan. A durable co-operation was however established between the research parties and contacts are continued to exist (at a lower level than planned) awaiting a possible solution to the problems.
* Knowledge transfer: In WPA knowledge has been exchanged between the partners. Partners were all involved in the design of the thermometer which led to thermometer requirements that are to be met by this thermometer: in terms of (amongst other) heat treatment, dimensions and mechanical ruggedness and electrical data analysis.
1. To be a replacement of base metal K and N-type and noble metal S and R-type thermocouples; measuring range: 1000 °C to 1500 °C (or possibly up to 1800 °C); At present the aim of a thermometer cannot be to range up to 1500 °C as the thermometers proved (so far) not able to withstand the temperature.
2. Measuring uncertainty as follows from a calibration with repeat measurements: 0.2% or better (i.e. better than 2 °C at 1000 °C); These criteria could not be tested.
3. Long term stability after 3 months of prolonged use at temperatures T > 1000°C: 0.5% or better (i.e. better than 5 °C at 1000 °C); These criteria could not be tested.
4. Response time equal or better than that of thermocouples in the same application; Measurements made on response time so far showed that the thermometers compare well with that of thermocouples used in these conditions.
5. Dimensions to match customer needs: generally 10 mm in diameter, any length can be made; Design has focussed on 12 mm diameter. Later, it was considered that where needed the design could still lead to smaller diameters, however partners in the project representing the industrial users considered this not a major issue where at present it is common practice to use diameters starting at 12 mm. Only the calibration laboratories are used to smaller diameters. NMi has designed its newly built testing and calibration furnace to fit 12 mm diameter thermometers.
6. Environmental durability against high pressures (up to 2000 bars), mechanical stresses, oxidising and reducing gases, EMI, microwave radiation for heating; These criteria could not be tested
7. Electrical connection with lead wires as is standardised, able to withstand high (100 °C) head temperatures; This objective has been met. Thermometer heads and the electrical connection therein can withstand temperatures of up to 200 °C.
8. In-situ recalibration possible through noise thermometry; This criterion could not be tested
9. Build-in current source to connect the thermometer with standard available temperature control and registration equipment, allowing easy exchangeability with thermocouples. Contacts were established with market parties that assured us that this is technically feasible. When MoSi2 thermometers would appear on the market present measurement equipment could be adjusted with existing technological options to adequately measure these thermometers. Within this project the thermometers could be measured to within sufficient accuracy with standard measurement equipment available from regular market parties such as Agilent (previously HP) and Keithley.
European consumers of process industry products are placing a growing emphasis on quality. Ever-stricter health, safety and hygiene standards are increasing the demand for monitoring of processes, causing continuously increasing demands for high quality sensors. Trends in industrial processing of high performance materials are for even higher processing temperatures and more use of special environments, like high pressures and reducing atmospheres. At present this part of industry is severely hampered by the lack of reliable and economical thermometers at temperatures in excess of 1000°C. During this project, a novel MoSi2 resistance thermometer will be developed that is expected to lower the cost of ownership by at least 40% compared to presently available thermometers, such as thermocouples. This new type of sensor will offer the possibility to correct for the effects of ageing and to apply in-situ calibrations. Moreover a 50% improved accuracy and resolution is expected, which enables considerable better thermal control of high-temperature industrial processing. This will lead to a better quality, reliability and yield, improved safety conditions, at least 10% reduction of energy costs and waste, and eventually to a rise of sales. The project comprises: - Research on sensor materials; - Research on sensor configurations adapted to requirements of high-temperature industrial processing; - Development of a standardised industrial demotype sensor. Long term tests on trial sensors will be carried out in various industrial processes and products to analyse the sensor's performance and prove its applicability in industry.
Funding SchemeCRS - Cooperative research contracts
PR9 9AG Southport
734 27 Halstahammar
2600 AR Delft
TW11 0LW Teddington
6534 AE Nijmegen