[12a-PA1-1~12] 1.5 Instrumentation, measurement and Metrology

[12a-PA1-2] Pressure Control of Two-Pressure Humidity Generator

〇Naoya Ishiwata¹, Tamio Niwa¹, Hisashi Abe¹ (1.National Metrology Institute of Japan (NMIJ), AIST)

Keywords:high humidity, humidity generator, pressure control

Humidity standard, which is a gas with known humidity, is needed for testing performance of hygrometers used in various industrial fields. In this study, the humidity generator for high humidity standard was automated in order to improve accuracy of generated dew point. The dew point of humid air generated by the instrument depends on temperature of saturation bath and air pressure in the generator. Therefore, fluctuations of bath temperature make accuracy of generated dew point worse. In order to address this problem, we developed an automated system for controlling dew point by regulating the air pressure in the generator. We applied this system to dew point generation under the condition that fluctuations of saturator temperature were large and compared generated dew point with dew points measured by chilled mirror hygrometers.