Use of a higher order Heydemann–Welch model to characterize a controlled clearance piston gauge

• Published in: Measurement : journal of the International Measurement Confederation Vol. 45; no. 10; pp. 2469 - 2471
• Main Authors: Olson, Douglas A., Gelany, Shaker A., Eltawil, Alaaeldin A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2012
• Subjects: Controlled clearance piston gauge; Piston gauge; Pressure standard; Primary pressure standard; Controlled clearance piston gauge; Primary pressure standard; Pressure standard; Piston gauge
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2011.10.047

► A Heydemann–Welch model for characterizing piston gauges accounts for non-linear behavior at high jacket pressures. ► The model is applied to a 290MPa piston gauge that improves the agreement to the existing NIST hydraulic pressure scale. ► The relative standard uncertainty of the new gauge with the higher-order model is 17.6×10−6 or less up to 290MPa. We present a new method for characterizing a controlled-clearance piston gauge as a primary pressure standard. This method requires operating the piston gauge to jacket pressures of over 80% of the system pressure. We present measurements on a hydraulic piston gauge with a 290MPa maximum pressure and a nominal piston diameter of 3.27mm. Measurements showed that the cylinder becomes stiffer as the jacket pressure increases, and that non-linear models of the Heydemann–Welch parameters improve the determination of the effective area. The relative standard uncertainty in the effective area of the piston gauge ranges from 16.0×10−6 to 17.6×10−6, and the agreement to the present NIST pressure scale is within the standard uncertainty.