Differential pressure flowmeters introduce a constriction in the pipe that creates a pressure drop across the flowmeter. When the flow increases, more pressure drop is created.

Impulse piping routes the upstream and downstream pressures of the flowmeter to the transmitter that measures the differential pressure to determine the fluid flow.

Different geometries are used for different measurements, including the orifice plate flow meter,segmental wedge flow meter, V-cone flow meter, and venturi tube flow meter, meter run flow meter and flow nozzle.