Effect of the kind of gas medium on calibration values of high gas pressure transducers

In an international comparison of high gas pressure standards up to 100 MPa, we have found that the calibration values of quartz Bourdon-type pressure transducers are affected by the kind of gas medium. In this study, focusing on the structure of the sensing element of the transducer and the density of the gas medium, we examined whether calibration values are affected by the weight of the pressure medium inside the sensing element or by the setting condition of the transducer. To evaluate the effect in detail, two horizontally mounted transducers were calibrated at different rotation angles. Changes in calibration values were expressed as a sinusoidal function of rotation angle. The rotation angles at which the calibration values were not affected by the kind of gas medium were identified. When the transducer was set at the identified rotation angle, the calibration values obtained by using nitrogen agreed well with those obtained by using helium.