Analysis of surface texture and its affect [sic] on pressure balances

2018-07-02T13:19:11Z (GMT) by Wan A.M.W. Mohamed
There are two primary methods to derive pressure from the base units of mass, length and time, i.e. a liquid manometer and a pressure balance. The key problem associated with pressure measurement using a pressure balance is centred on the determination of the effective area of the piston-cylinder assembly (PCA) under the appropriate operating conditions. Dimensional measurements alone cannot provide formally recognised traceability to the SI unit, the pascal (Pa), without extreme levels of data and mathematical modelling, supported with extensive comparison histories with other instruments of proven performance. Intercomparisons have demonstrated that the uncertainty of measurements using pressure balances, have reached a plateau of approximately 5 to 10 ppm due to unexplained phenomena. The aim of this research is to identify any evidence of pressure dependency as a function of surface texture applied onto the piston of 35 mm diameter PCA, using a gas-operated (gas-lubricated) pressure balance. [Continues.]