What are the advantages and disadvantages of electromagnetic flow meters?

working of electromagnetic flow meter emerged rapidly in the 1960s with the development of electronic technology. Their principle is based on Faraday's law of electromagnetic induction, and they are used to measure the volumetric flow of conductive fluids in pipelines, including strongly corrosive liquids such as acids, alkalis, and salts. Electromagnetic flow meters are widely used in industries such as oil, chemical, metallurgy, textiles, food, pharmaceuticals, papermaking, as well as in environmental protection, municipal management, and water conservancy projects. This time, AUTO Instruments will explain the characteristics and drawbacks of electromagnetic flow meters to provide you with more knowledge about them.

Main Characteristics of Electromagnetic Flow Meters:

1. Simple structure of the transmitter: water flow meter electromagnetic have a simple transmitter structure with no moving parts and no throttling components that obstruct fluid flow. Therefore, they do not cause additional pressure loss when the fluid passes through, and they do not cause problems like wear or clogging. This makes them particularly suitable for measuring slurries, sewage, and other liquid-solid two-phase flows containing solid particles, as well as viscous liquids. Additionally, because they have no moving parts, they can be made with corrosion-resistant insulating linings and electrodes made from durable materials (known as anti-corrosion electromagnetic flow meters), making them highly resistant to corrosion and suitable for measuring various corrosive media.

2. Unaffected by temperature, viscosity, density, and conductivity: As a volumetric flow measurement instrument, the electromagnetic flow meter is not affected by the temperature, viscosity, density, or conductivity (within a certain range) of the measured medium. Therefore, once calibrated with water, it can be used to measure the flow of other conductive liquids without the need for additional corrections.

3. Wide measuring range: The electromagnetic meter for water has an extremely wide range, with the range ratio of a single electromagnetic flow meter reaching up to 1:100. Furthermore, the flow meter's signal is only proportional to the average flow velocity of the measured medium and is not affected by the flow conditions (whether laminar or turbulent) as long as the flow distribution is axisymmetric.

4. No mechanical inertia and sensitive response: Electromagnetic flow meters have no mechanical inertia and respond quickly, making them capable of measuring instantaneous pulsed flow. They also have good linearity, allowing the measured signal to be directly converted into a standard output signal by the converter. The measurement data can be displayed on-site or transmitted remotely.

Although electromagnetic meter has these excellent characteristics, there are still some limitations, which are as follows:

Disadvantages:

1. Limited to conductive liquids: Electromagnetic flow meters can only measure conductive liquids and cannot be used to measure gases, steam, or liquids containing a large amount of gas.

2. Temperature and pressure limitations: Due to the insulation material used in the measurement tube, which is limited by temperature, current industrial electromagnetic flow meters cannot measure high-temperature or high-pressure fluids.

3. Influenced by flow distribution: The electromagnetic flow meter's flow signal is proportional to the average flow velocity under axisymmetric flow conditions. Therefore, the meter requires a certain length of straight pipe sections before and after the measuring tube to ensure accurate measurements.

4. Efficiency improvements in human and material resources: Electromagnetic flow meters contribute to the optimization of product value and input through physical and chemical process improvements, leading to more efficient services for human life.