Magnetic flowmeters, also known as simply mag meters, offer a number of practical advantages over traditional flow metering technologies which employ mechanical measuring techniques. The minimally invasive, no-moving-parts design of the electromagnetic flow meter is the key to these advantages.
The mag meter only has two non-moving parts that contact the measured fluid media – a liner which protects the flow body from the fluid and a pair of electrodes which detect the velocity of the flowing fluid. Compared to traditional mechanical flow measurement techniques such as turbine and positive displacement which rely on rotating mechanical gears and bearings, the mag meter’s simple construction provides for longer life, less maintenance, lower pressure drop, and overall lower cost of ownership. This design allows the mag meter to be used with virtually any conductive liquid regardless of density, viscosity, chemical composition, or fluid condition/particulate count.
These factors, combined with the mag meter’s superior accuracy and ease of installation, have made it the flowmeter of choice in many industries and applications including municipal/wastewater, factory au.tomation, food & beverage and pulp & paper
SmartMeasurementTM offers a complete line of mag meters to address any flow measurement application where an electromagnetic flowmeter may be the preferred technology. For general purpose applications, the value-priced ALMAG-WP is the meter of choice. This meter is offered with wafer type and ANSI & DIN flanged process connections and features an easy-to-read OLED display module that provides a variety of industry standard outputs including frequency/pulse, analog 4-20 mA, RS-485/modbus, Profibus, and HART. A wide variety of material selections are available for the ALMAGWP’s liner and electrodes, insuring that it can be fabricated to be compatible with virtually any conductive fluid.
A number of special purpose mag meters are also available from SmartMeasurement. For applications where either no power or only solar power are available, such as oil-water separators found in the oil & gas industry, the battery powered ALMAG-BAT is offered. This meter features its own internal long-life lithium-ion battery which may or may not be supplemented with a solar panel, along with special firmware that de-energizes and re-energizes the electromagnetic coils at predetermined intervals in order to extend battery life. The battery-powered magnetic flowmeter is also popular in irrigation applications where there is no power available at the installation site, as seen in the agricultural industry.
For large pipe sizes where it may not be practical to use a traditional in-line mag meter, the insertion-mounted ALMAG-IS is offered. This meter can accommodate line sizes of up to 120” (3000 mm) at a fraction of the purchase cost of an inline magnetic flow meter sized for the same pipe. The insertion mounting method provides further savings opportunities via reduced installation costs. The insertion mag meter is frequently used in municipal applications where larger pipe sizes are common.
Another special purpose electromagnetic flowmeter offered by SmartMeasurement is the ALMAG-EG. The ALMAG-EG is actually a multi-component system that consists of an inline electromagnetic flowmeter, two RTD temperature sensors, and a flow computer. The RTD sensors allow for a supply and return line temperature measurement to be made and used in conjunction with the flow rate measurement provided by the mag meter in order for the flow computer to calculate a BTU/energy consumption rate. This system is frequently used for BTU/energy measurement required in building automation applications.
Finally, SmartMeasurement also offers the ALMAG-HP for high pressure applications up to 6000 psi working pressure. This product is a specialized version of the general purpose electromagnetic flowmeter that features a heavy wall flow tube to accommodate higher pressures and high-pressure flanged process connections such as ANSI 900# RTJ and ANSI 1500# RTJ type. This mag meter may be used in any application where high pressure conductive fluids need to be measured, such as high-pressure water injection in the oil & gas industry, or fluid-power/hydraulic applications that are employing water-based hydraulic fluids.
For a more detailed discussion of the operating principle of our electromagnetic flow meter designs, please visit our Magnetic Measuring Principle page.
Request a quote today, or contact SmartMeasurement for more information on our electromagnetic flow meter models.
Magnetic Flow Meter Operation And Application Considerations
Magnetic flow meters rely Faraday’s law of electromagnetic induction which states that an inductive voltage is generated when a conductor moves through a magnetic field. Inside of the mag meter’s flow tube, when a conductive fluid passes through the magnetic field generated by the meter’s electromagnetic coils at a right angle to the field, the voltage induced at the electrode is directly proportional to the density of the magnetic field, the distance between the sense electrodes, and the velocity of the fluid. Therefore, the voltage measured across the meter’s electrode, measured in mV, is directly proportional to the fluid velocity of the measured media. Since the area inside of the flow tube is a known quantity, the measured velocity can then very easily be used to accurately calculate the volumetric flow rate through the meter.
Magnetic flow meters, also known as mag meters, do not contain any moving parts, rotating gears, turbines, or bearings. Instead, they rely on two electrodes to measure the density of the induced magnetic field that results from an electrically conductive fluid, such as water, flowing through a pipe. The density of the magnetic field is directly proportional to the fluid velocity of the flowing liquid. They offer a number of practical advantages over traditional flow metering technologies which employ mechanical measuring techniques. The only real limitation of the electromagnetic flow meter is that the measured fluid media must be electrically conductive (> 5μS/cm). Non-conductive fluids, such as oil and other petroleum-based fluids, cannot be measured with mag meter technology.
Because the only wetted components in a SmartMeasurement electromagnetic flow meter are the electrodes and the liner, these components can be fabricated from a variety of materials to make the mag meter compatible with virtually any electrically conductive fluid, including aggressive acids. Provided that the electrical conductivity of the fluid is ≥ 5μS/cm, magnetic flowmeters can detect the flow of any clean, multi-phase, dirty, corrosive, erosive, or viscous liquids, or slurries.
The non-invasive, no moving parts nature of the electromagnetic flowmeter allows users to select a suitable meter for applications in many different industries, ranging from factory automation to food and beverage processing to mining, municipal/wastewater treatment, and pulp & paper production.
FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION