Coriolis Mass Flow Meter Main Features Advantages Disadvantages explained in this blog
Main Features
A Coriolis meter can be applied for variety of applications ranging from adhesives and coatings to liquid nitrogen.
Typical rangeability of curved tube designed Coriolis meters vary from 100:1 to 200:1 whereas for straight-tube meters its rangeability is limited i.e. about 30:1 to 50:1. Besides, accuracy of straight tube meters is low.
In case of Coriolis meters, no compensation is needed for temperature and pressure variations. Also mass measurement is insensitive to changes in viscosity and density.
They are particularly helpful for handling liquids whose viscosity changes according to velocity while temperature and pressure remains constant.
These are called universal meters, since they are capable enough to measure nearly all liquids, slurries and gases. They can measure all liquid flows such as Newtonian, non-Newtonian and moderately dense gases as well.
They can be employed to measure liquid density also.
No Reynolds number restrictions are allied with Coriolis flow meters.
They are also not affected by deformations in velocity profile.
The advantages & limitations of Coriolis flow meter are:
Advantages of Coriolis Meters
Coriolis flow meter is capable of measuring a wide range of fluids that are often incompatible with other flow measurement devices. The operation of the flow meter is independent of Reynolds number; therefore, extremely vicious fluids can also be measured. A Coriolis flow meter can measure the flow rate of Newtonian fluids, all types’ non-Newtonian fluids, and slurries. Compressed gases and cryogenic liquids can also be measured by some designs.
Coriolis flow meters provide a direct mass flow measurement without the addition of external measurement instruments. While the volumetric flow rate of the fluid will vary with changes in density, the mass flow rate of fluid is independent of density changes.
Coriolis flow meters have outstanding accuracy. The base accuracy is commonly on the order of 0.2%. In addition, the flow meters are linear over their entire flow range.
The rangeability of flow meters is usually on the order of 20:1 or greater. Coriolis flow meters have been successfully applied at flow rates 100 times lower than their full scale flow rate.
A Coriolis flow meter is capable of measuring mass flow rate, volumetric flow rate, fluid density and temperature — all from one instrument.
The operation of the flow meter is independent flow characteristics such as turbulence and profile. Therefore, upstream and downstream straight run requirement and flow conditioning are not necessary. They can also be used in installations that have pulsating flow.
Coriolis flow meters do not have internal obstructions witch can be damaged or plugged by slurries or other types of particulate matter in the flow stream. Entrained gas or slugs of gas in the liquid will not damage the flow meter. There are no moving parts witch will wear out require replacement. These design features reduces the need for routine maintenance.
The flow meter can be configured to measure flow in either the forward or the reverse direction. In revere flow there will still be a time or phase difference between the flow detector, but the relative difference between the two detector signals will be reversed.
Coriolis flow meter designs are available witch allow for use in sanitary applications, and for the measurement of shear sensitive fluids. Materials are available to permit the measurement of corrosive fluids.
Disadvantages of Coriolis Meters
Coriolis flow meters are not available for large pipelines. The largest Coriolis flow meter that is currently available has a maximum flow rating of 25,000 lb/min (11,340 kg/min), and is equipped with 6 in. (15 cm) flanges. When larger flow rates must be measured, two or more flow meters mounted in parallel are required.
Some flow meter designs require extremely high fluid velocities in order to achieve a significant amount of time or phase difference between the flow detector signals. This can result in extremely high pressure drops across the flow meter.
Coriolis flow meters are expensive. However, the cost of a Coriolis meter is often comparable to (or below) the cost of a volumetric meter plus densitometer used together to determine the mass flow rate.
Coriolis flow meters have difficulty measuring the flow rate of low- pressure gas. Application with pressure less than 150 psig are marginal with the flow meter designs that are currently available. Low-pressure gases have low density, and their mass flow rate is usually very low.
In order to generate enough mass flow rates to provide sufficient Coriolis force to be measured, the gas velocity must be extremely high. This in turn may lead to prohibitively high pressure drops across the meter.