YI Hong, SUN Guohua, LI Zhanyuan, REN Changqing, YANG Ju

(National Institute of Metrology, Beijing 100013)

Abstract: Low Frost Point Generator (LFPG) for humidity transfer and intercomparison is very important. It consists of a singlepressure generation techniques. For preconditioning, a pre-saturator is used to bring the frost point of the inlet stream close to the saturator temperature and to assure the efficient saturation of main saturator for the LFPG. The temperature of saturator is stable within 0.01°C, and the difference between the saturator temperature and frost -point generated at the saturator outlet is less than 0.02°C. The humidity generators of our design have wide range and high accuracy. A preliminary comparison in a frost point temperature range from -60 °C to -20 °C was carried out. For the limited range of data studied, these agree within the stated uncertainty of the generator.

Key words:  dew/frost point generator, saturator, humidity standard, humidity measurement