Reducing Uncertainty in a Type J Thermocouple Calibration Process

Abstract

Thermocouples are used in many manufacturing processes in order to read the actual temperature of the product. Calibration of thermocouples is critical wherever they are used. However, the uncertainties must be considered and the factors that affect the uncertainty value must be regarded during the calibration of thermocouples. In this study, design of experiments by Taguchi method has been performed in order to reduce uncertainty during calibration of Type J thermocouples. Within the scope of this study, parameters which are assumed to effect temperature oscillations have been determined and necessary experiments have been conducted using temperature well and proper inserts. The parameters were selected as insert material, thermocouple immersion depth and type. It can be concluded that the immersion type has the highest effect, whereas immersion depth has minimum effect on the uncertainty value. As a result of the study, a value for parameters which results in best possible temperature uniformity of the well is achieved.