Mass flow meters measure flow rate in units of mass flow, for example, lbs/min.  Mass flow meters can be configured to either measure liquid or gas flow.  Common mass flow meter technology types are thermal meters and Coriolis meters.  Thermal meters use a heated sensing element isolated from the fluid flow path.  The flow stream conducts heat from the sensing element.  The conducted heat is directly proportional to the mass flow rate.  In a Coriolis meter fluid is passed through a small vibrating flow tube causing a deflection of the flow tube proportional to the mass flow rate of material.  The basis of good flowmeter selection is a clear understanding of the requirements of the particular application. Measuring the flow of liquids and gases is a critical need in many industrial plants. In some operations, the ability to conduct accurate flow measurements is so important that it can make the difference between making a profit and taking a loss. In other cases, inaccurate flow measurements or failure to take measurements can cause serious (or even disastrous) results.