Primary dew-point generation between 1°C and 60°C at LPM

EUROMET collaborative project has been set up between Finish Centre for Metrology and Accreditation (MIKES) and Croatian Laboratory for process measurements (HMI/FSB-LPM) with the objective to provide HMI/FSB-LPM with two new primary dew-point generators. Both generators operate on single pressure - single pass principle and together cover the dew-point temperature range from -70°C to 60°C, with gas flow rates up to 2.6L/min. This article presents the design of the high range generator (HRS), which operates in a dew-point range between 1°C and 60°C. To investigate how close the generator is to the ideal saturation, MIKES conducted several efficiency tests, which will also be described. Results of the tests show that HRS generator is sufficiently efficient for a primary realization of the dew-point temperature scale in the specified ranges. The estimated standard uncertainties due to the non-ideal saturation efficiency are found to be between 0.02 °C and 0.05 °C.