Abstract
The primary dew-point standard of National Metrology Institute of Japan (NMIJ) over the dew-point range of −10 °C to 95 °C is a humidity generator based on the two-pressure two-temperature method. In this generator, the dew-point temperature of generated air is calculated by using the pressure and temperature, assuming that the air in the saturator is in equilibrium with liquid water. Therefore, the evaluation of the degree of saturation of water vapor in the saturator is important. In this study, the saturation efficiency of the NMIJ two-pressure two-temperature humidity generator has been re-evaluated. The NMIJ humidity generator has a presaturator that consists of a water bath and a bubbling element that can supply water vapor to the airflow into the main saturator. The amount of water vapor in the air output from the PS is altered by changing the PS temperature. The dew-point temperatures of the generated air were measured by a chilled-mirror hygrometer under various conditions of PS pressure and temperature. The saturator efficiency of the generator has been evaluated from the relationship between the measured dew-point temperature and the PS temperature. When the temperature of the PS was lower than that of the saturator, the amount of water in the air was insufficient to achieve saturation. When the temperature of the PS was slightly higher than that of the saturator, saturation was obtained.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
