Moisture and temperature

Thermodynamic traceability

In the field of thermodynamic traceability we are investigating the feasibility of establishing direct traceability for cryoradiometers and electrical quantities for our reference pyrometer, over a range from 1000 °C to 2000 °C. 

At present, we have access to a fixed point for gold at 1064 °C, with comparisons against strip lamps for higher temperatures, which limits the uncertainty of measurement. 

Inhomogeneity in thermocouples

Inhomogeneity in thermocouples is another area that we regard as important in an industrial perspective.  This phenomenon directly causes measurement errors in many applications that are sufficiently large to create real problems.  This is very clearly demonstrated by the very different measurement results often produced by a practical measurement in comparison with a calibration measurement. 

We have previously developed a methodology for measurement of inhomogeneities, which is now being refined to make it more suitable for industrial thermocouples. 

Thermal capacitivity

Questions have arisen in recent years concerning the determination of specific thermal capacitivity of very different materials, for which existing methods used by SP are unsuitable.  The reasons can be such as inhomogeneities in the material, air inclusions, the size of test pieces, structure etc.  A calorimetric method can generally be used, but commercial instruments are available only for very small samples.  

We have developed a temperature sweep method that has so far been demonstrated to work from 5 °C to 60 °C, based on the known thermal capacitivity of water as a function of temperature.  Calorimeters have been constructed in several sizes in order to meet the requirements of a range of sizes of samples.