A gravimetric flow standard system is established and in operation for the calibration of flowmeters with light oil (Calibration Oil K, Castrol). The Light Oil Flow Standard System (LOFSS), as one of the national flow standard system in Korea, can provide a direct primary calibration for any conventional oil flowmeter. The system, which is operated by the standing start and finish mode with the static weighing method, measures mass electronically from a gyroscopic scale. The flow of up to 350 m3/h is generated by two pumps and the main test line is designed with a 200 mm pipe diameter. For the uncertainty analysis of flow measurement by LOFSS, the equilibrium equation based on the calibration principle of the standard system was derived. The standard flow quantity is determined from the independent variables. Therefore the uncertainty of the independent variables were scrutinized with consideration of the operation conditions and combined for the expression of the uncertainty of the flow quantity determination. The evaluation procedure method follows the ISO Guide to the Expression of Uncertainty in Measurement. The expanded uncertainties in volume and mass flow measurement in the range of 18 and 350 m3/h are 0.04 and 0.01%, respectively. The uncertainty budget shows the contribution of the uncertainty of the independent variables to that of the flow quantity measurement.
Overview and Uncertainty Analysis for an Irrigation Flow Measurement Facility
