NIST Measurement Services: NIST Calibration Services for Gas Flow Meters. PistonProver and Bell Prover Gas Flow Facilities

摘要

This document provides a description of the small and medium range gas flowcalibration facilities at the National Institute of Standards and Technology (NIST) Fluid Flow Group, as reported in NIST Special Publication 250 (1) for Test Nos. 18010C-18040C and 18050S, Flow Rate Measurements. The Fluid Flow Group can perform gas meter calibrations and special tests at flows between 3.7 x 10(-5) m(3)/min and 1.4 m(3)/min (0.001 standard cubic feet per minute (SCFM) and 51 scfm, reference temperature and pressure are 293.15 K and 101325 Pa) using positive displacement techniques. The flow rate of gas passing through the meter under test is determined from pressure, temperature, volume, and transit time measurements of a displaced volume of gas. Two types of displacement devices are usedL mercury-sealed piston provers and bell gasometers, or bell provers. This report describes the techniques used for calibrating meters and presents the uncertainty analysis associated with such calibrations.