Measuring the mass of a substance that has passed a particular point in a specified time period.
The measurement of mass flow is called the mass flow rate, and this is defined as the amount of mass that will be transferred in a unit period of time i.e. ṁ = m / t.
Mass flow can be measured either directly using a mass flow meter, or indirectly by combining other parameters such as flow velocity, area, density, temperature and pressure.
There are many different units used for measuring mass flow rate. The type of substance, size of cross sectional area, flow speed, and geographic region, will all dictate the mass and time units which are the most convenient to use for a particular flow measurement. The mass flow rate unit derived from SI units is kilograms per second (kg/s).
Featured flow measurement products
10 kPa orifice plate differential pressure transmitter for water flow measurement - Pressure sensor for measuring the differential pressure generated by water flowing through an orifice plate in a pipe, and converting the output to a water flow measurement. 
Water system peak demand pressure and flow data logger - Identify peak demand and low-pressure events in your water system with the P-Triton-PF data logger. User-configurable logging regimes, 5-year battery life, and IrDA wireless communication.