Enhancing the Speed and Accuracy of Coriolis Flow Measurements

This article describes a number of new developments in Coriolis flowmeters, including high-speed signal processing for faster and more accurate measurements, robustness achieved through the use of an anti-vibration mechanism, and high accuracy density measurement.

A Coriolis flowmeter directly measures mass flow rate, density, and temperature at the same time. Moreover, based on these directly measured three variables, the volume flow rate and concentration of mixture can be calculated.

The mass flow rate is measured by a Coriolis meter based on the interaction of Coriolis forces generated between the flowing fluid and vibrating measurement tube. The principle is outlined in Fig.1. The U-shaped tube is repeatedly swung around the fixed end as a pivot like a cantilever. When fluid flows in this tube, Coriolis forces are generated at both the inlet and outlet sides of the tube according to the ascent and descent of the tube. Since the directions of the forces generated at inlet and outlet sides are opposite, torque is created, generating a torsion angle in the tube. Because the Coriolis force is proportional to the mass flow of the fluid, the mass flow can be measured by detecting the torsion angle.