Magnetic flow meter is also called electromagnetic flow meter, mag flow meter or magmeter. Magnetic flow meter is a volumetric flow meter. Measures liquids or liquid slurries that have a minimum conductivity of 5 µS/cm.
Magnetic flow meter can be used to measure the volume flow of conductive fluid in a closed pipeline. Magnetic flow meter is ideal for water and wastewater applications which is conductive or water based. Magnetic flow meter also applied in the flow measurement and control in the fields of chemical and petroleum industry.
Learn more about how magnetic flow meters work and the technology behind Sino-Inst’s Magnetic flow meters.
Sino-Inst offers a variety of Magnetic Flow Meters for flow measurement. If you have any questions, please contact our sales engineers.
Featured Magnetic Flow Meters
What are Magnetic Flow Meters?
Magnetic Flow Meters (Electromagnetic Flowmeters) are abbreviated as EMF. It is a new type of flow measurement instrument that developed rapidly with the development of electronic technology in the 1950s and 1960s.
Electromagnetic flow meters are volumetric flow meters which do not have any moving parts to wear. Reducing the need for maintenance or replacement. Electromagnetic flow meters are based on the principle of electromagnetic induction. The flow of conductive fluid is measured based on the electromotive force induced by the conductive fluid through an external magnetic field Of an instrument.
Magnetic Flow Meters perform extremely well in many municipal and processing applications. And have become the meter of choice for measuring conductive liquids such as water or slurry.
Electromagnetic Flow Meters Features
- The measurement is not affected by changes in fluid density, viscosity, temperature, pressure and conductivity;
- There are no parts obstructing the flow in the measuring pipe. There is no pressure loss, and the requirements for straight pipe sections are lower. Unique adaptability to slurry measurement;
- Reasonably choose sensor lining and electrode materials. That is, it has good corrosion resistance and wear resistance;
- The converter adopts a novel excitation method, with low power consumption, stable zero point and high accuracy. The flow range can reach 150:1;
- The converter and the sensor can be integrated or separated;
- The converter adopts 16-bit high-performance microprocessor. 2x16LCD display. Convenient parameter setting. Reliable programming;
- The flowmeter is a two-way measurement system with three totalizers inside. The total forward volume, the reverse total volume and the total difference value. It can display the forward and reverse flow rates. It has a variety of outputs. Current, pulse, digital communication , HART;
- The converter adopts surface mount technology (SMT). It has self-check and self-diagnosis functions;
- The measurement accuracy is not affected by changes in fluid density, viscosity, temperature, pressure and conductivity. The sensor induced voltage signal has a linear relationship with the average flow rate, so the measurement accuracy is high.
- There are no obstructions in the measuring pipeline, so there is no additional pressure loss. There are no moving parts in the measuring pipeline, so the sensor has an extremely long life.
- Since the induced voltage signal is formed in the entire space filled with magnetic field, it is the average value of the pipe surface. Therefore, the straight pipe required by the sensor is shorter, and the length is 5 times the pipe diameter.
- The converter adopts the latest and most advanced single-chip microcomputer (MCU) and surface mount technology (SMT) in the world. It has reliable performance, high precision, low power consumption, stable zero point and convenient parameter setting. Display cumulative flow, instantaneous flow, flow rate, flow percentage, etc.
- Two-way measuring system, which can measure forward flow and reverse flow. Using special production technology and high-quality materials. Ensure that the performance of the product remains stable for a long time.
Types of Magnetic Flow Meter
How are electromagnetic flowmeters classified?
Electromagnetic flowmeter is one of the most widely used liquid flowmeters for measuring the flow of liquid fluids (satisfying a certain conductivity). Many users have no way to start when choosing electromagnetic flowmeters. It is because of the types of electromagnetic flowmeters and the applicable range of materials Do not really understand.
Therefore, this article first elaborates on the classification of electromagnetic flowmeters and how the types are divided.
Classified by excitation method
1) DC excitation type
This kind of electromagnetic flowmeter is very small. It is only used to measure the flow of liquid metal. Such as mercury at normal temperature and liquid sodium and potassium at high temperature.
2) AC power frequency excitation type
The earlier electromagnetic flowmeter used 50Hz power frequency mains excitation. Now it has been gradually replaced by low frequency rectangular excitation.
But when measuring the liquid-solid two-phase flow such as mud and ore slurry, the low-frequency rectangular wave excitation method cannot overcome the peak noise generated by the solid rubbing the surface of the electrode. However, the power frequency AC excitation instrument does not have this shortcoming. So domestic and foreign Some electromagnetic flowmeters still use AC excitation.
3) Low-frequency rectangular wave excitation type
It is used for low-frequency rectangular wave excitation with low power consumption and stable zero point, which is the main excitation method for electromagnetic flowmeters at present.
The waveform has two values: “positive-negative” and “positive-zero-negative-zero” three values.
The excitation frequency of some electromagnetic flowmeters can be set by the user. Generally, small-diameter instruments use higher frequencies. Large-diameter instruments use lower frequencies.
4) Dual frequency excitation type
The waveform of the excitation current is a high-frequency rectangular wave superimposed on a low-frequency rectangular wave. The main purpose is to overcome the slurry noise and flow noise in the binary rectangular wave excitation. Improve the stability and response characteristics of the instrument.
Classified by the composition of sensors and converters
1) Separate type
This is the main type of electromagnetic flowmeter.
The sensor is installed on the flow pipeline. The converter is installed in the instrument room or near the sensor that is easy to install and operate. The distance is generally tens to hundreds of meters.
The advantage is that the converter can be far away from the harsh environmental conditions on site. The inspection, adjustment and parameter measurement of electronic devices are more convenient.
The sensor and the converter are assembled together. It is installed on the process pipeline and directly outputs the current (or frequency) standard signal reflecting the flow rate.
The advantage is that the connection length of the flow signal line and the excitation line between the sensor and the converter is shortened. There is no external wiring of this kind. Therefore, the electrical wiring is simple and the price is relatively cheap.
But it is easy to be restricted by pipeline layout. If it is installed in a place that is not easily accessible to people, maintenance is very inconvenient. In addition, the electronic devices in the converter are installed on the pipeline, which is susceptible to the influence of liquid temperature and pipeline vibration.
Classified by connection method
According to the connection mode of the sensor and the pipeline, it can be divided into flange connection, flangeless clamp connection and threaded connection.
Classified by purpose
1) Universal type
General electromagnetic flowmeters used in industrial fields such as water supply and drainage, sewage treatment, medicine, food, biology and fine chemicals are the main types of electromagnetic flowmeters. There is a range requirement for the conductivity of the measured medium, which generally cannot exceed the upper and lower limits.
2) Explosion-proof type
Used in places with explosive atmosphere.
Due to the large energy of the excitation current, the flameproof type is still the main type at present.
In recent years, an intrinsically safe type, namely a safe spark electromagnetic flowmeter, has appeared in foreign countries. The excitation power is greatly reduced, and it can be made into an integrated type, and all are installed in dangerous areas.
Electromagnetic flowmeters used in industries such as medicine, food, and biochemistry. They must meet the relevant hygiene requirements in terms of regular bacteria arrival and easy disassembly and cleaning.
4) Waterproof type
Used for sensors installed under the ground. Can withstand short-term water immersion.
5) Diving type
It is used to measure the flow when the free surface of the open channel or underfilled channel is free. The sensor is under the open channel interception baffle and works under water for a long time. The structure and use are different from the general electromagnetic flowmeter.
6) Insert type
Electromagnetic flow sensor for large pipe diameter. The sensor is inserted radially from the pipe opening to measure the local flow rate and estimate the flow rate. The accuracy is low, but the price is cheap, and it is suitable for control systems.
Classified by whether in contact with the liquid to be measured:
(1) Contact type electrode electromagnetic flowmeter
The electrode in contact with the liquid is the traditional structure of EMF, usually a pair of electrodes.
There are two pairs of electrodes in the large-diameter instrument industry.
Partial tube EMF can also use 3 pairs of motors or strip electrodes.
(2) Non-contact electrode electromagnetic flowmeter
The large-area electrode is closely attached to the outer surface of the lining (or insulating measuring tube), and the flow signal is picked up by capacitive coupling. The electromagnetic flowmeter that can measure the capacitance of the contact electrode is referred to as the capacitive electromagnetic flowmeter.
Covering the inner surface of the lining with a non-conductive layer such as grease or a thin insulating structure layer will not affect the measurement. However, if the covering layer is a conductive film, the meter will not indicate.
Classified according to the flow sensor structure:
(1) Short tube type electromagnetic flowmeter
The short tube structure is like the structure of the traditional electromagnetic flowmeter. The flow sensor is connected to the pipeline system with a measuring pipe section.
(2) Plug-in electromagnetic flowmeter
The plug-in electromagnetic flowmeter sensor is essentially an electromagnetic flow rate sensor. The excitation coil and the electrode are assembled into a rod shape. It is inserted from the opening on the pipeline to be measured. The measured flow rate is multiplied by the coefficient of the pipeline area preset by the converter. Take the flow. In addition to single-point “point flow velocity”, there are also those who measure multi-point “radial velocity”.
This type of instrument is suitable for large pipelines. Because the local flow velocity is measured to estimate the fluid flow, the measurement accuracy is much lower than that of the short tube type. Usually only used for process control, not suitable for trade accounting measurement. But the price is relatively cheap.
Classified according to the connection mode of the flow sensor and the pipeline:
(1) Flange connection electromagnetic flowmeter
The traditional connection method for flange connection. There are connecting flanges at both ends of the sensor, which are fixed with bolts between the flanges of the pipeline and can be installed in one direction. Large-caliber sensors all use this connection method. The volume and weight are larger than the clamping connection method.
(2) Clamping and connecting electromagnetic flowmeter
The connection method developed in recent years during the clamping connection. The sensor itself cannot be flanged, and is clamped between the two flanges of the pipeline to connect to the piping system with a longer bolt. The sensor of this method is small in size and light in weight, and has strong adaptability to different pressure specifications and standard pipe flange hole spacing. But it is only suitable for smaller pipe diameters (below 200mm), and the working pressure of the liquid is lower.
(3) Sanitary electromagnetic flowmeter
Hygienic connection, connected with IDF blessing piece of International Dairy Federation. Realize quick disassembly and installation, convenient for daily and frequent cleaning.
(4) Threaded connection electromagnetic flowmeter
Thread connection method for small-diameter instruments. This type of instrument is mostly used in industries such as medicine and food, and places such as pharmaceutical injection.
Threaded connections are also mostly used in petroleum and geological prospecting for high pressure water injection or cement slurry flow measurement above 16-25MPa, and the thread shape is trapezoidal.
Typical Applications of Electromagnetic Flowmeter
Electromagnetic flowmeters have been used for more than 50 years and have been widely used worldwide. The fields involve water/sewage, chemical, pharmaceutical, paper, food and other industries.
Large-caliber meters are mostly used in water supply and drainage projects.
Small and medium calibers are often used in places where solid and liquid are both equal and difficult to detect fluids or high requirements.
Small calibers and tiny calibers are often used in places with hygiene requirements such as the pharmaceutical industry, food industry, and biological engineering.
- Water / Wastewater Industry
- Food and Beverage
- Brewing, Distilling, and Wine makening
- Pulp and Paper
- Mining, Mineral Processing
Magnetic Flow Meter Working Principle
Magnetic flow meters use the principle of Faraday’s Law of Electromagnetic Induction to measure the flow rate of liquid in a pipe. In the magnetic flowmeter pipe parts, a magnetic field is generated, and channeled into the liquid flowing through the pipe.
Faraday’s Law states that the voltage generated is proportional to the movement of the flowing liquid. A conductor moving through a magnetic field produces an electric signal within the conductor. And the singal is proportional to the velocity of the water moving through the field.
As fluid flows through the magnetic field, conductive particles in the fluid create changes. This variation is used to measure and calculate the velocity of water flow through the pipe. When the fluid moves faster, more voltage is generated. The electronic transmitter processes the voltage signal to determine liquid flow.
What is the principle of magnetic flow meter? – Faraday’s Formula
E is proportional to V x B x D where:
E = The voltage generated in a conductor
V = The velocity of the conductor
B = The magnetic field strength
D = The length of the conductor
To apply this principle to flow measurement with a magnetic flow meter. First is to state that the fluid being measured must be electrically conductive for the Faraday principle to apply.
As applied to the design of magnetic flow meters, Faraday’s Law indicates that:the signal voltage (E) is dependent on V, B, D.V is the average liquid velocity ;
B is the magnetic field strength ;
D is the length of the conductor ( which in this instance is the distance between the electrodes).
To learn more about Magnetic Flow Meters, this video by Emerson gives a good explanation.
Video source: https://www.youtube.com/watch?reload=9&v=lRSjYjg9WRo
Advantages of using Electromagnetic Flow Meters.
- High precision and stability
- Two-way measurement
- No pressure loss
- No moving parts
- May be for sanitary purposes
- Large size available
- Dirty liquid and mixed fructose are ok
Disadvantages of using Magnetic Flow Meters
- Can not be used to measure gas, steam and liquids containing a lot of gas;
- Cannot be used to measure liquid media with very low conductivity. The electromagnetic flowmeter cannot measure petroleum products or organic solvents and other media;
- Cannot be used to measure high temperature media. At present, it is restricted by the lining material and electrical insulation material of the measuring tube of the electromagnetic flowmeter for general industry;
- The electromagnetic flowmeter is easily affected by external electromagnetic interference.
Magnetic Flow Meter Price
Magnetic Flow Meter has different calibers, different materials, different media, different linings, different meter heads, and different functions, so the price is different!
The Magnetic Flow Meter price list is attached below for reference only!
The final quotation is subject to the parameters!
|Diameter/DN||Lining rubber (USD)||Lined with PTFE (USD)||Electrode||Power||Material|
|DN15||485||647||316L (Standard configuration)||24V/220V||Carbon steel|
|DN20||493||647||316L (Standard configuration)||24V/220V||Carbon steel|
|DN25||500||647||316L (Standard configuration)||24V/220V||Carbon steel|
|DN32||537||654||316L (Standard configuration)||24V/220V||Carbon steel|
|DN40||566||654||316L (Standard configuration)||24V/220V||Carbon steel|
|DN50||588||662||316L (Standard configuration)||24V/220V||Carbon steel|
|DN65||618||676||316L (Standard configuration)||24V/220V||Carbon steel|
|DN80||676||691||316L (Standard configuration)||24V/220V||Carbon steel|
|DN100||706||750||316L (Standard configuration)||24V/220V||Carbon steel|
|DN150||728||794||316L (Standard configuration)||24V/220V||Carbon steel|
|DN200||757||838||316L (Standard configuration)||24V/220V||Carbon steel|
|DN250||809||985||316L (Standard configuration)||24V/220V||Carbon steel|
|DN300||926||1118||316L (Standard configuration)||24V/220V||Carbon steel|
|DN350||985||1368||316L (Standard configuration)||24V/220V||Carbon steel|
|DN400||1081||1441||316L (Standard configuration)||24V/220V||Carbon steel|
|DN500||1184||1765||316L (Standard configuration)||24V/220V||Carbon steel|
|DN600||1368||1904||316L (Standard configuration)||24V/220V||Carbon steel|
|DN700||1640||3574||316L (Standard configuration)||24V/220V||Carbon steel|
|DN800||2556||3868||316L (Standard configuration)||24V/220V||Carbon steel|
|DN900||3088||4574||316L (Standard configuration)||24V/220V||Carbon steel|
|DN1000||4044||5926||316L (Standard configuration)||24V/220V||Carbon steel|
Factors affecting the price of Magnetic Flow Meters
- The larger the diameter of the flowmeter, the higher the price. For example, DN250 electromagnetic flowmeter is more expensive than DN25 electromagnetic flowmeter. On the contrary, the smaller the diameter, the lower the price.
- The flowmeter is divided into: integrated type and split type. Split type electromagnetic flowmeter is more expensive than integrated type electromagnetic flowmeter. The high reason is that the expensive money for the split type is shielded wire money.
- The flowmeter is divided into: ordinary type, anti-corrosion type, anti-corrosion type. The price of electromagnetic flowmeter is higher than that of ordinary electromagnetic flowmeter. The reason for the higher price is that the lining is distinguished. The anti-corrosion type is tetrafluoroethylene lining, mainly for measuring acid Alkaline medium. The common type is rubber lining, mainly for measuring sewage and ordinary water medium.
Sino-Inst offer over 50 Magnetic Flow Meters, with Best Price.
A wide variety of Magnetic Flow Meters options are available to you, such as free samples, paid samples.
Sino-Inst is Magnetic Flow Meters suppliers, located in China. Magnetic Flow Meters products are most popular in North America, Mid East, and Eastern Europe. The United States, and India, which export 99%, 1%, and 1% of Magnetic Flow Meters respectively.
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Magnetic flow meter is also called electromagnetic flow meter, mag flow meter or magmeter. Magnetic flow meter is a volumetric flow meter. Measures liquids or
Product SKU: Magnetic Flow Meters
Product Brand: Sino-Inst
Product Currency: USD
Product Price: 400
Price Valid Until: 2036-09-02T14:06:24
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