The Orifice Plate is a flow measurement device using the Venturi effect to produce a pressure drop from which the flow rate can be inferred. This primary element consists of a thin metal plate with a sharp-edged upstream aperture (orifice) inserted between two flanges at the location where the flow must be determined. This model is provided with three different plates.

The Orifice Plate requires the use of a differential-pressure transmitter to transform the pressure drop into a usable flow rate value.