The Development of a Device for In Situ Calibration of Thermometers

Prototype comparator devices have been designed and constructed for the calibration of thermometers on-site and in situ. The uncertainties that can be obtained using this device can be compared with those of block calibrators. The system has reduced stem conduction losses by limiting gradients and consequent heat flows. Presently, the range of the prototype applications is limited to between −90 °C and +150 °C. The article shows details on the construction, discusses evaluation tests and calibration results, and gives example uncertainty budgets.