Industry Insight: Coriolis Mass Flow Meters

Coriolis Flow Meters (commonly known as mass flow or inertial flow meters) measure the mass flow rate of a liquid or gas passing through a pipe or enclosed tube.

Because mass flow is measured, the measurement is not affected by fluid density changes. Coriolis mass flow meters can measure flow extremely accurately so they are often used to measure high value products or the introduction of fluids that affect the production of high value products.

Coriolis flow meters measure the force resulting from the acceleration caused by mass moving toward (or away from) a center of rotation.

This effect can be experienced when riding a merry-go-round, where moving toward the center will cause a person to have to “lean into” the rotation so as to maintain balance.

The effect can be demonstrated by flowing water in a loop of flexible hose that is “swung” back and forth in front of the body with both hands. Because the water is flowing toward and away from the hands, opposite forces are generated and cause the hose to twist.

In a Coriolis flow meter, the “swinging” is generated by vibrating the tube(s) in which the liquid or gas flows. The amount of twist is proportional to the mass flow rate of fluid passing through the tube(s).

Sensors attached to the tube measure the twist and generate a linear flow signal.

coriolis flow meter diagram

Early Coriolis mass flow meters were single-tube designs with a U-tube shape similar to the garden hose (described above). These flow meters could be significantly affected by vibration in all but the smallest sizes.

Subsequent designs split the flow into two flow streams that measure the relative twist between the two tubes. These designs were much less susceptible to vibration and allowed Coriolis mass flow meters to be installed in “normal” piping systems without extensive mechanical supports.

Electronic and mechanical improvements allow more recent designs to include single-tube Coriolis mass flow meters with straight tubes that reduce pressure drop and reduce the probability of plugging.

Most Coriolis mass flow meters can measure fluid flow, fluid density, and the temperature of the outside wall of the pipe in the flow meter. Some Coriolis meters can also measure the fluid viscosity, while other Coriolis mass flow meters can measure two-phase flow accurately.

Coriolis Flow Meter Applications

Coriolis Flow Meters are very useful in measuring mass flow of liquid fluids such as acids, chemicals, water, caustics. In addition, it can also be used for measuring flow of gases and vapours.

In case of measuring mass flow of gases, it is necessary to reduce the pressure drop to attain accurate measurements.

They are widely-used throughout the chemical, mining, paper, petroleum, petrochemical, power, water, pulp & paper industries.

Coriolis mass flow meters are designed for specialised implementations; providing a source of ultra-accurate flow information, leading to improved system productivity and greater process cost efficiency.

Application Cautions

If pressure drop is not an issue, then a Coriolis Flow Meter should be applied at the upper portion of the flow. At lower flow rate, the overall accuracy of the measurement is reduced.

——

Coriolis Flow Meters Supplier

PWA Group can supply a range of high quality, precise Coriolis flow meters.