What best describes a Coriolis flowmeter?

• A. A mass flow meter with specially formed tubing that is oscillated at a right angle to the flowing mass.
• B. A volumetric flow meter using a turbine.
• C. A differential pressure flow meter with an orifice.
• D. An ultrasonic time-of-flight meter.

Answer: (A)

Coriolis flowmeters measure mass flow directly by vibrating a specially formed tube so that it oscillates perpendicular to the flowing fluid. When fluid moves through this vibrating tube, the Coriolis force acting on the moving mass causes a twist or phase change in the tube’s motion. Sensors detect this twist and, from the vibration rate and the amount of twist, compute the mass flow rate. This approach primarily yields mass flow (and can also provide density from the vibration behavior), which is why it’s distinct from other common meters: a turbine measures volumetric flow by counting rotating blades, a differential-pressure meter infers flow from pressure drop across an orifice, and an ultrasonic time-of-flight meter uses sound travel time to estimate flow.