Orifice Plate Flow Meter Working Principle

Orifice plate flow meter is a type of differential pressure flow meter that is commonly used in clean liquid, gas, and stream mass flow measurement. Using Bernoulli’s principle, the reduced area increases velocity and decreases pressure (vena contracta), where the flow rate is proportional to the square root of this differential pressure.

Founded by Daniel Bernoulli, this principle is derived from the conservation of energy. In a moving fluid, the sum of static pressure, kinetic energy per unit volume, and gravitational potential energy per unit volume remains constant along a streamline. When fluid velocity rises, its kinetic energy increases, requiring a compensating drop in pressure or potential energy. The equation applies to idealized conditions—neglecting viscosity and compressibility—to describe how pressure, velocity, and height interrelate in flow systems.