Differential pressure (DP) flow meters operate based on Bernoulli’s principle, which states that the pressure drop across an obstruction in a flowing fluid is proportional to the flow rate. These meters typically consist of a primary element (such as an orifice plate, Venturi tube, or flow nozzle) and a secondary element (a differential pressure transmitter). The most commonly used differential pressure flow meters are orifice meters and Venturi meters.