The coriolis mass flow meter is a highly accurate device designed to measure the mass flow rate of a fluid directly, unlike other meters that measure volume and require additional corrections for density. Its operation is based on the Coriolis principle, a phenomenon observed in rotating systems.

At its core, the meter contains one or two U-shaped or straight flow tubes through which the fluid passes. These tubes are vibrated electromechanically at their natural resonant frequency, similar to a tuning fork. When no fluid is moving, the tubes vibrate symmetrically.

The key operation begins when a fluid flows through the oscillating tubes. As the fluid moves toward the point of maximum vibration, it must accelerate to keep up with the tube’s motion. Conversely, as the fluid moves away from this point, it decelerates. This acceleration and deceleration generate an inertial force—known as the Coriolis force—which acts on the tube walls. This force causes the tube to twist slightly in a characteristic corkscrew motion.

This twisting, or deflection, is directly proportional to the mass flow rate of the fluid. Sensors, typically optical or electromagnetic, are positioned at the inlet and outlet sides of the tube to measure the phase shift (time difference) between the two sides. A greater mass flow results in a larger phase shift. The meter’s transmitter processes this sensor data to calculate the precise mass flow rate.

A major advantage of this technology is that it can also simultaneously measure the fluid’s density. The natural resonant frequency of the vibrating tube changes with the mass of the fluid inside it, allowing for density calculation.

In summary, by exploiting the Coriolis effect, these meters provide direct, highly accurate mass flow measurements independent of the fluid’s temperature, pressure, or viscosity, making them indispensable in industries from chemicals and oil and gas to food and beverage.