Flowmeters are used to measure Flow. Flow is a motion of fluids such as liquids, gas, or slurries.
Flow can be measured in volumetric or mass flow rates with units such as liters per second or kilograms per second.
The volumetric flow rate is denoted by Q
Q = v A
V = flow velocity
A = cross-sectional of the area
The mass flow rate is denoted by m
m = Q p
Q = volumetric flowrate
p = density
Flow can be measured in a variety of ways and the most commonly used flow meters are listed below
The following flow meters are for mass flow: Coriolis flow meter, thermal mass flowmeter, ultrasonic, and rotometers.
The following flow meters are for volumetric flow rate: vortex meter, turbine flowmeters, positive displacement meters, and differential pressure transmitter.
When measuring the flow of compressible liquids by using a volumetric flow meter, there will be an error if the density is not constant.
When the volumetric flow of incompressible liquid is measured, the presence of suspended bubbles will cause an error. So that it must be cleared before the fluid enters the meter.
Mass flow meters are insensitive to density, viscosity, pressure, and temperature changes. Hence Mass flow meters are accurate for measurements compared to volumetric flow meters.