Electromagnetic flow meter is an instrument widely used in the field of industrial fluid measurement. Electromagnetic water flow meter estimates the flow rate by measuring the induced potential generated when the conductive liquid moves in a magnetic field. It has the advantages of accurate measurement, fast response speed and high reliability. Therefore, it has been widely used in liquid flow measurement.
How does an electromagnetic Water flow meter work?
The electromagnetic flowmeter generates a constant alternating magnetic field through the switching direct current I with alternating polarity, and the direction of the magnetic field is perpendicular to the direction of medium flow. During flow measurement, the medium flows through the magnetic field, and the flowing medium is equivalent to a moving conductor, which induces an electromotive force Ue proportional to the flow velocity of the medium, as hown in Figure 1.
Ue = B*L*v
B: Magnetic strength
L: Electrode spacing
V: Medium flow rate
The electromagnetic flowmeter detects the induced electromotive force through two measuring electrodes and transmits it to the converter for processing. Based on the cross-sectional area A of the measuring pipe, the volume flow Q of the fluid can be calculated.
Q = A·v
What is the Range of the Electromagnetic Water Flow Meter?
There are many types of electromagnetic flowmeters according to different application scenarios and detection media. The range and flow rate under different application conditions are different. Its inner diameter size range is wide, from DN6 to DN2200. The range ratio can reach 1:120, and the flow rate of the measured medium can be selected within the range of 0.5~12m/s, which can meet the needs of most industrial applications.
What is the Life Expectancy of an Electromagnetic Water Flow Meter?
The service life of electromagnetic flowmeter is generally about 8-10 years. However, the specific service life is affected by the following factors:
- Usage environment: Electromagnetic flowmeters are often used in various harsh environments, such as high temperatures, strong acids, strong alkalis and corrosive liquids, which may cause damage to the flowmeter.
- Fluid properties: Different types of fluids have different chemical compositions and pH values, which may cause different degrees of corrosion and damage to the material of the electromagnetic flowmeter. Therefore, when choosing an electromagnetic flowmeter, users should consider the properties of the fluid.
- Material selection: A good flowmeter depends not only on the material and lining, but also on the electrode selection of the medium. If measuring corrosive media, the 316 electrode is recommended.
- Maintenance: Regular maintenance and maintenance are important measures to extend the life of the electromagnetic flowmeter. Timely cleaning, inspection, replacement of parts and other work can effectively reduce the occurrence of failures and extend the service life.
What are the Advantages of an Electromagnetic Water Flow Meter?
- High measurement accuracy, up to ±0.2% or ±0.5% of the indicated value, and available for measuring forward and reverse direction flows.
- Wide measuring range of up to 1,500:1.
- Wide measuring range: Generally, it can measure the flow rate in the range of 0.1m/s to 12m/s. It can adapt to the measurement of pipelines with different flow rates and different diameters.
- Low requirements for conductivity: minor influence by medium viscosity, temperature, pressure, and density. Liquid with a conductivity of 2 μS/cm is allowed for measurement.
- Strong corrosion resistance: Different electrodes and lining materials can be selected to measure a variety of corrosive media.
- Neither additional energy loss nor clogging will be caused due to the absence of flow restriction and moving parts in the measuring tube.
- Strong anti-interference ability: Unique noise treatment technology and digital filtering allow for filtering of the interference caused by dirt attached to pipelines and electrodes.
- Rich display content: The total amount, instantaneous flow rate, flow velocity, and percentage flow are displayed.
- Low installation requirements: 5D for the front straight pipe section and 2D for the rear straight pipe section.
What are the different types of magnetic flow meters?
Different industries that manage flow rates need metering devices tailored to their specific operational requirements. This principle also applies when selecting an electromagnetic flow meter. The variety of electromagnetic flow meters available ranges from basic, cost-effective models to more advanced and precise ones, with the latter being more expensive due to their complexity and accuracy.
There are three common types of electromagnetic flow meters: insertion, in-line, Battery Powered, Sanitary, Split Type and low flow. The choice among these types depends on the specific needs of the application and the type of data required.
Insertion Magnetic Flow Meters
Insertion magnetic flow meters can be installed through a ball valve or by drilling a hole in the pipe where hot tap or insertion installation is desired. They can be installed in pipelines with an internal diameter of two to 360 inches through a small tapping. As with other magnetic flow meters, insertion magnetic flow meters have an electromagnetic sensor and flow converter. A major benefit of insertion flow meters is that they can be installed where there is limited space.
To install the flow meter, it is screwed into a pipe joint. During installation, ensure that the indicators are aligned parallel to the pipe and the direction of the fluid flow. The probe should be inserted so that the sensor is centered within the pipe, following the meter’s installation depth guidelines.
Sanitary Magnetic Flowmeter
Sanitary Type electromagnetic flowmeter is a flow measurement device specially designed for food, hygiene and chemical industry, which adopts new hygienic lining material and lining process to ensure compliance with hygienic requirements of food industry. It adopts stainless steel shell and stainless steel clamp connection, which is convenient for quick disassembly and cleaning of electromagnetic flowmeter. Therefore, the sanitary type electromagnetic flowmeter is not easy to contaminate in the process of use, can effectively prevent the measurement of liquid residue in the measurement tube, in dairy and beverage processing has been widely used.
Battery-powered Electromagnetic Flowmeter
Battery-powered electromagnetic flowmeter is a flow measurement instrument that does not require an external power supply and is powered by a built-in battery. It is usually used in places where there is no access to the power grid or the power supply is unstable, such as remote areas, temporary installation points, remote monitoring, etc.
It is widely used in urban water supply, sewage treatment, irrigation systems and other places, and can monitor flow without an external power supply.
A Wide Range of Applications
Magnetic flow meters are crucial across numerous industries due to their versatility and precision, particularly in applications involving conductive materials. These devices play a vital role in ensuring accurate measurements and maintaining safety and quality standards across various sectors. They are most suitable for industries dealing with conductive fluids, ensuring optimal performance and reliability.
- Chemical Processing: Ensuring precise measurements for complex chemical reactions and maintaining safety and quality standards.
- Industrial Water Management: Efficiently managing water usage and treatment processes, ensuring sustainability and regulatory compliance.
- Mining & Metal Processing: Monitoring slurry flows and other challenging applications with high accuracy and reliability.
- Pulp and Paper: Managing flow rates in pulp production and paper manufacturing processes, ensuring consistency and quality.
