Principle
An orifice meter is a piece of equipment used to measure the flow rate of a gas or a fluid. It mainly consists of an orifice plate, an orifice plate housing, and a meter tube.
The liquid or gas whose flow rate is to be determined is passed through the orifice plate.
This creates a pressure drop across the orifice plate which varies with the flow rate, resulting in a differential pressure between the outlet and inlet segments.
This pressure drop is measured and is used to calculate the flow rate of the fluid or gas.