What is the difference between Volumetric flow meter and Mass flow meter?

Interview Question: What is the difference between Volumetric flow meter and Mass flow meter?

Answer:

Volumetric flow meter gives flow rate in terms of volume viz liters/hr,gallon, m3/hr etc whereas mass flow meter gives direct mass flow rate viz kg/hr or tons/hr etc

mass = density* volume

volumetric flow = area*velocity

volumetric flow gives how much volume is passing through a given point,it does not give the real mass of fluid is passing.Mass flow is highly depends on the density as well as on temperature,change in these changes the mass flow.