Volume Flow Rate

Process applications involve the measurement of volume or mass flow rate of a fluid, gas (such as air) or liquid (such as water). Some of the methods of measurement of volume/mass flow rate are: variable area type flow meters; drag effect type flow meter and other types of flow meters such as: positive displacement type flow meters, vortex shedding type flow meter and turbine type flow meter. Rotameter is also referred to as a drag effect meter since the volume/mass flow measurement is based on equilibrium of a body under the action of inertia and drag forces. This chapter discusses some of the factors to be considered in the selection of flow meters. Calibration is required only when the absolute accuracy of a meter is required. More expensive the fluid being metered higher is the desired accuracy and hence the more important the quality of calibration.