Coriolis Flow Meter: Working principle

Gaspard Gustave de Coriolis – a French scientist developed a new method for measuring the flow of gas or liquids in pipelines based on his principle called the Coriolis Effect.

Coriolis Flow Meter.

A single or dual tube is located inside the pipeline of each Coriolis flow meter. An exciter causes the tube to oscillate constantly. If there is now flow, the tube oscillates uniformly. As soon as the flow starts to flow in the tube, an additional twist is imposed on the oscillations as a result of liquid inertia.

Sensors are located at the inlet and outlet of the tube and register this basic oscillation precisely.  Now due to the Coriolis effect, the inlet and outlet sections of the tube oscillate in different directions at the same time. Highly sensitive sensors pick up this change of time and space.  This is called a phase shift. This is a direct measurement of how much gas, the liquid is flowing through the pipe.  Higher the phase shift, the more the flow in the tube vice versa.

Density can also be measured by measuring the oscillation frequency. The frequency of oscillations for water-filled tube is more, whereas honey-filled tube is less. This is due to the density difference.

Advantages:

Coriolis flowmeter is insensitive to viscosity, pressure, and temperature.

Coriolis flowmeter can be configured to measure flow in either the forward or reverse direction.

Coriolis flowmeter can be configured to measure flow in either the forward or reverse direction.

Coriolis flowmeters do not have any internal obstructions that can be damaged or plugged by viscous slurries or other types of particulate matter in the flow stream.

The operation of the flowmeter does not depend on the Reynolds number.

Coriolis flowmeters provide a direct mass flow measurement without the addition of any external measurement instruments.

They display outstanding accuracy. The flow meters are highly linear over the entire flow range.

Rangeability is on the order of 20:1. Coriolis flowmeters have been successfully applied at flow rates 100 times lower than their rated scale flow rate.

The operation of the flow meter is independent of flow characteristics such as turbulence and flow profile. Therefore, the requirement of upstream and downstream straight pipe run requirements and flow conditioning is not required.

Limitation of Coriolis Flowmeters:

Coriolis flowmeters are expensive.

Coriolis flowmeters are difficulty in measuring the flow rate of low-pressure gas.

Coriolis flowmeters are not available for the large pipelines.