Uncertainty evaluation in the calibration of Pt/Pd thermocouples up to copper freezing point at NIS-Egypt

Abstract

Abstract. The dissemination of traceability to the International Temperature Scale of 1990 (ITS-90) through comparison calibration of thermocouples, is playing an important role in metrology institutes, secondary laboratories and industrial measurements. The previous studies of the Pt/Pd thermocouples at NIS-Egypt, shows promise of achieving significant improvements uncertainty of temperature measurements up to 960 • C. In this paper we describe the uncertainty assessment on the measurements of the calibration of Pt/Pd thermocouples at fixed point cells up to the freezing point of copper and by the comparison technique following a defined heat treatment at 1100 • C. All the measurements on Pt/Pd thermocouples were carried out using NIS facilities.

Consistency of the national realization of dew-point temperature using NIS standard humidity generators

“…Also it was noted that the difference at À10°C is different from the differences at À20°C and 0°C. This was also noted previously [8,9] and thus confirms the reproducibility of each generator. These differences have no evidences of relevant systematic bias between the two generators.…”

“…The uncertainty budget comprises a composition of the uncertainties of each element in the humidity generator [8][9][10][11][12]. Table 1 shows an example of uncertainty budget at 0°C for the two generators.…”

NIS two-pressure humidity generator

“…International Journal of Metrology and Quality Engineering The expanded uncertainty of measurements is described by an uncertainty budget [6]. The measurement uncertainty for the temperature sensors of two-pressure humidity generator was estimated to be about ±0.2…”