A Coriolis Flow Meter is also known as a Coriolis Mass Flow Meter. It is mainly used where high accuracy of measurement is required. A Magnetic Flow Meter is also known as an Electromagnetic Flow Meter. It is mainly used to measure the flow of conductive liquids.
Both Coriolis flow meters and magnetic flow meters are capable of measuring the flow of different media. But they have different characteristics in many ways. This article will compare the Coriolis flow meter and the magnetic flow meter. We hope we can help you choose the right device for measuring flow.
What is a Coriolis Flow Meter?
A Coriolis flow meter is a device that measures the mass flow of a fluid in a pipe using the Coriolis principle. It is proportional to the mass flow. A Coriolis Flow Meter consists of a transducer and a flow detection element.
Advantage:
1. A Coriolis flow meter can meet most industrial needs in terms of corrosion, dirt, explosion and wear resistance. It can measure oil, chemical media, paper black liquor, slurry, gas, solid particles, and high-viscosity objects.
2. There is no obstruction inside the pipe, and no moving parts; it is not easy to wear. It is easy to carry out cleaning, routine maintenance, and other operational tasks.
3. The inlet and outlet directions of the sensor tubes of different sizes can be adjusted according to the needs of the site. The import and export of straight pipe section configuration requirements are low.
4. A Coriolis flow meter can measure the flow of multi-phase fluids.
5. It can be synchronized to obtain the volume flow rate, temperature, density and other parameters. Less sensitive to common influences such as pressure, temperature, density, viscosity, and flow rate distribution.
Disadvantage:
1. Cannot measure low-density media and low-pressure gases.
2. Not vibration-resistant, more sensitive to vibration.
3. Expensive, mostly used in the measurement of demanding occasions.
4. Can not be used for larger pipe diameter measurement; the current maximum pipe diameter is DN150.
What is Magnetic Flow Meter?
A magnetic flow meter uses Faraday’s law of electromagnetic induction and it mainly measures conductive liquid volume flow.
Large large-diameter magnetic flow meter is more often used in water supply and drainage projects. Small and medium diameter is commonly used in solid-liquid dual-phase and other difficult-to-measure fluids or high requirements of the place.
For example, the paper industry pulp liquid and black liquid, non-ferrous metallurgical industry, mineral slurry, coal slurry plant, chemical industry, the strong erosion of liquid and iron and steel industry blast furnace, wind mouth cooling water control and monitoring leakage, long interval pipeline coal hydraulic transmission of flow measurement and control. Small small-diameter magnetic flow meter is commonly used in the pharmaceutical industry, food industry, biological engineering and other places with health requirements.
Advantage:
1. A magnetic flow meter is suitable for measuring liquid-solid two-phase fluids containing solid particles or fibers. such as pulp, coal water slurry, slurry, mud and sewage.
2. A magnetic flow meter does not produce pressure loss due to the formation of the detection of flow. Instrument resistance is only a uniform length of pipe along the resistance. For the requirements of low resistance loss of a large diameter water supply pipeline is most suitable.
3. A magnetic flow meter to measure the volume flow. It is not subject to fluid density, viscosity, temperature, pressure and conductivity changes significantly.
4. Compared with other flow meters, the front straight pipe section requirements are lower.
5. The measurement range degree is large, usually 20:1 ~ 50:1. The optional flow range is wide. Full-scale liquid flow rate can be selected in the 0.5 ~ 10m / s.
6. The magnetic flow meter caliber range than other varieties of flow meters. It can measure positive and negative bidirectional flow, and can also measure pulsating flow.
7. A variety of lining materials can be used to measure aggressive fluids.
Disadvantage:
1. A magnetic flow meter can not measure the conductivity of the liquid that is very low, gas, steam and contains large bubbles of liquid.
2. A general magnetic flow meter can not be used for liquids above 200 ℃. Because of the limitations of lining materials and electrical insulation materials. At the same time, it can not be used for low-temperature media. Because the measuring tube outside the condensation or frost will damage the insulation.
The Differences of Coriolis Flow Meter and Magnetic Flow Meter
Based on Sino-Inst’s many years of experience in flow measurement, the main differences between Coriolis and Magnetic Flow Meters are as follows:
Different Working Principle
Magnetic Flow Meters work based on Faraday’s electromagnetic induction. The magnetic flow meter operates based on Faraday’s Law of Electromagnetic Induction. When an electrically conductive fluid flows through a magnetic field, an induced potential is created in the fluid. The induced potential is directly proportional to the flow rate of the liquid. By measuring the induced potential, a magnetic flow meter can accurately calculate the volume flow rate of a liquid.
Read More about: How Does a Magnetic Flow Meter Work？
Coriolis flow meters operate based on the mechanics of motion. As the fluid enters the sensor, the fluid will separate. During the measurement process, the drive coil excites the pipe to vibrate in phase with its intrinsic resonant frequency. As the pipe vibrates, a sine wave is created by the voltage generated across each sensor. This can represent the motion of one pipe relative to the other. The time lag between the two sine waves is called Delta-T and is proportional to the mass flow rate.
Different Applicable Media
Coriolis flow meters are suitable for measuring the mass flow of gases, liquids and multiphase fluids. Coriolis flow meters can measure a wide range of fluids, including slurries, non-Newtonian fluids, high-viscosity fluids, liquids with traces of gases, suspensions, single-phase fluids, and medium- to high-pressure gases with sufficient density.
A magnetic flow meter is suitable for measuring the volume flow of liquids and conductive liquids. Magnetic flow meter mainly measures acid, alkali, salt and other solutions, slurry, sewage water, tap water and so on. But the magnetic flow meter can not measure non-conductive liquids.
Different Precision
The Coriolis mass flow meter is one of the most accurate flow meters among all flow meters. It has an accuracy of 0.1%. Electromagnetic flow meters have an accuracy of 0.5%. Higher accuracy levels can be customized by contacting us.
Different Cost
Because Coriolis flow meters have the highest accuracy. Therefore, the cost of Coriolis flow meters is higher than electromagnetic flow meters.
Read More about: Turbine Flow Meter and Coriolis Mass Flow Meter-Difference and Selection
Sino-Inst Featured Coriolis Flow Meters and Magnetic Flow Meters
How to Choose the Coriolis Flow Meter and Magnetic Flow Meter?
Choosing a Suitable Magnetic Flow Meter:
It requires considering many factors. The following is a detailed selection guide for your actual needs:
1. Fluid Properties
We should ensure that the conductivity of the fluid to be measured is higher than that required by the instrument (usually 5 μS/cm). According to the chemical properties of the fluid to choose the appropriate lining materials (such as PTFE, rubber wear) and electrode materials (stainless steel, Hastelloy, etc.).
Fluids containing solid particles or fibers may require the selection of a wear-resistant lining and a more suitable electrode structure. For fluids containing impurities or suspended solids, the self-cleaning ability of the flow meter and ease of maintenance need to be considered.
2. The Flow Rate Range
Select a flow meter with a flow rate in the range of 1-10m/s at full flow. Avoid the flow rate being too low or too high, resulting in a decline in measurement accuracy. According to the actual working conditions of the flow range is used to determine the appropriate caliber. Avoid using too large a flow meter, resulting in a decrease in measurement accuracy.
Applications with low flow rates or low flow rates during start-up: consider selecting a model with a lower flow rate limit.
3. The Pressure and Temperature
According to the working pressure of the piping system to select the electromagnetic flow meter with the appropriate pressure level to ensure safe operation. Consider the working temperature of the fluid, select the lining material and sealing material that can withstand the temperature of the model.
Attention to one of the electromagnetic flow meters and the split of the different temperature ranges.
4. The Pipe Size and Installation
Sensor caliber is not necessarily the same as the pipe diameter. According to the flow rate to choose the appropriate caliber; if necessary, use of reducer connection.
Installation Types:
Flange: suitable for most pipeline connections, easy to install.
Insertion: Suitable for pipe diameters above DN300, easy to install. However, the accuracy is slightly lower than the one-piece pipe section.
Clamping type: suitable for special occasions. No need to cut the pipe, fast installation.
Read More about: Magnetic Flow Meter Installation Guide and Magnetic Flow Meter Calibration and Maintenance Guide.
5. Other Factors
We should ensure that the installation location can be well grounded to prevent external electromagnetic interference. Select the appropriate level of accuracy, magnetic flow meter accuracy up to 0.5% or higher.
We should choose a reputable brand with good after-sales service to reduce the failure rate and maintenance costs. Choose models that support fieldbus or wireless communication protocols to adapt to automation control systems. Select the appropriate protection level according to the harshness of the installation environment.
How to choose a Coriolis flow meter?
When selecting a model, you need to comprehensively consider many factors.
According to the different properties of the measurement medium. such as fluid type, temperature, pressure, viscosity and corrosivity, etc. At the same time, we should combine the actual application of the flow range. To avoid overloading or accuracy reduction due to improper selection of the measurement range. We have to consider the cost and the actual production of the demand for measurement accuracy.
We also need to consider the installation of the Coriolis flow meter. Depending on the fluid to be measured, such as liquids, gases or mixed slurries, we have to choose the correct installation square.
Environmental conditions, brands and manufacturers, as well as price factors, are also key points to focus on during the selection process. A harsh environment should be selected with the corresponding protection level of the flow meter.
Well-known brands and manufacturers with the strength to protect product quality and after-sales service. The price should be based on a comprehensive consideration of all aspects of product performance.
What is another name for the Coriolis flow meter?
The Coriolis flow meter is also known as the Coriolis mass flow meter.
What is the difference between an ultrasonic and a magnetic flow meter?
Magnetic flow meters working principle:
Magnetic flow meters work according to Faraday's law of electromagnetic induction. When an electrically conductive liquid flows through a measuring tube and cuts the magnetic lines of force generated by an excitation coil. An induced electromotive force proportional to the flow rate of the liquid is generated on electrodes that are perpendicular to both the liquid's flow direction and the direction of the magnetic field.
By measuring the magnitude of the induced electromotive force can be deduced from the fluid flow. This formula determines that the principle of measurement is relatively direct and with a variety of physical properties of the fluid is not very relevant.
Ultrasonic flow meter working principle:
When the ultrasonic beam propagation in the liquid, the liquid flow will make the propagation time produce small changes. Ultrasonic propagation time change is proportional to the liquid flow rate. Zero flow, the two sensors transmit and receive sound waves, and take the same time. Medium flow, counter-current direction of the acoustic wave transmission time is greater than the downstream direction of the acoustic wave transmission time.
Magnetic flow meter for the measurement of conductive liquids. It featured high accuracy, a wide range, no pressure loss, and other advantages. But it can only measure conductive liquids and is susceptible to electromagnetic interference and has high installation requirements.
An ultrasonic flow meter is a non-contact measurement. It can measure a variety of media, is easy to install. However, its stability is affected by a variety of factors and the requirements of the straight section of the demanding.
In the choice of a flow meter, if the measurement of conductive liquids and very high precision, the production environment of electromagnetic interference is small at the same time as the installation conditions to meet the requirements, the magnetic flow meter may be a better choice. When the measurement of non-conductive media or the need for installation without stopping production, as well as large diameter pipeline flow measurement, the ultrasonic flow meter is more advantageous. A magnetic flow meter can measure the fluid with impurities. Ultrasonic flow meters are mostly used to measure clean and separate media.
Read More about: Ultrasonic Flow Meter Technical Guide
What is the accuracy of a magnetic flow meter?
Magnetic flow meters typically have accuracy ratings ranging from 0.25-2.5%. Sino-Inst can customize higher accuracy ratings to meet user needs.
All in all, both Coriolis flow meters and magnetic flow meters have excellent performance in many industrial processes. However, we need to consider various factors when choosing them. I’m sure you have a general understanding of their differences after reading this post.
If there are still questions, you can always contact us. Our relevant technicians will provide you with free technical support. We can also customize the measurement solution for you according to your needs.
