Use of strain gauge pressure transducer as working pressure standard up to 500 MPa

This paper describes the calibration of a strain gauge transducer (700 MPa full scale) against a primary pressure standard (500 MPa full scale) maintained at the National Physical Laboratory (NPL), India, over a pressure range of 500 MPa. The calibration data obtained at the NPL are also compared with the calibration data taken at Istituto Di Metrologia ‘G. Colonnetti’ (IMGC), Italy, using the primary pressure standard of IMGC in the possible overlapping pressure region of 158 – 457 MPa, with particular reference to reproducibility, hysteresis and the calibration equations.It is found that the reproducibility between the calibration factor of the standard at NPL and that at IMGC is typically ± 5 X 10⁻⁴ and the highest difference in the pressure values of NPL and IMGC calcualted using the second-order polynomial calibration equation is well below 2 X 10⁻³, the expected uncertainty for the transducer. This suggests a possible use of the strain gauge transducer as a working pressure standard in this pressure range if the accuracy required in the pressure measurement is of the order of 2 X 10.⁻³.