Presentation Information
[2P36]Measurement of thermal transpiration effect for precise pressure measurement by capacitance diaphragm gauge and the uncertainty evaluation
*Hajime Yoshida1, Kimihiro Sato2, Yoshinori Takei1, Wataru Osada1, Tomoya Kanzaki2, Toru Yamaguchi2, Yasuhide Yoshikawa2 (1. National Institute of Advanced Industrial Science and Technology , 2. Azbil Corporation)
An experimental system was developed to measure the thermal transpiration effect at temperatures up to 100 ℃. The principle was based on a relative method using two pipes with significantly different inner diameters. Two capacitance diaphragm gauges (CDGs) with a sapphire diaphragm were employed to measure the thermal transpiration effect. The measurements were compared with calculations using Takaishi-Sensui (T-S) equation with six types of constants set A*, B* and C* proposed by Takaishi and Sensui, Furuyama, Yasumoto, Setina, York; and Iwata. The expanded measurement uncertainties ranged from 0.46 % to 0.30 % with the confidence level of 95 %. These were evaluated by combining various uncertainty sources related to the two CDGs, such as calibration, long-term instability, nonlinearity, zero instability, and the measurement reproducibility. Calculations of T-S equation with Yasumoto’s and Setina’s constants agreed with the experimental measurements within the uncertainty.