As one of the major types of process instruments, flow meters for industrial play an irreplaceable role in ensuring safe production and reducing energy consumption.When designing a sewage flow monitoring system for an industrial park, the selection of an appropriate flow meter is crucial. Based on an understanding of the measurement medium, a comprehensive comparison of the principles, application ranges, and performance characteristics of several commonly used flow meters is conducted. The goal is to select a flow meter that operates reliably and provides accurate flow data, serving as a reference for engineering and technical personnel.
Electromagnetic Flow Meter for Industrial
Faraday’s Law of Electromagnetic Induction is the fundamental principle behind electromagnetic flow meters for industrial . Structurally, an electromagnetic flow meter consists of two main parts: an electromagnetic flow sensor and a converter. The sensor is installed in the industrial sewage discharge pipeline, where it detects the induced electromotive force generated by the conductive medium moving through the magnetic field. The converter receives this signal, amplifies it, and outputs a standard electrical signal proportional to the flow rate. This enables flow display, accumulation, and control adjustments.
Application Scope of Electromagnetic Flow Meters for Industrial
Electromagnetic Flow Meters for Industrial are primarily used to measure the volumetric flow rate of various conductive liquids, with a minimum conductivity requirement of greater than 10⁻⁷ S/m. They cannot be used for non-conductive fluids (such as oil), liquids containing large air bubbles, or steam. Based on structure, electromagnetic flow meters are categorized into integrated and remote types. The remote type is used in environments with strong vibrations, explosive gases, or high-temperature fluids, while the integrated type is sufficient for general applications.
Electromagnetic flow meters for industrial for industrial are particularly suitable for:
- Highly corrosive wastewater containing acids, alkalis, and salts
- Abrasive fluids such as cement slurry, mineral slurry, and fiber solutions
- Hygienic applications like dairy products, alcoholic beverages, and syrups
For water supply and drainage projects, large-diameter flow meters are commonly used, whereas in more demanding or difficult measurement scenarios, small-diameter flow meters are preferred.
Application Features of Electromagnetic Flow Meters for Industrial
Electromagnetic flow meters for industrial have minimal energy consumption and are unaffected by fluid quality, pressure, temperature, viscosity, or density. They offer a wide velocity adjustment range, typically from 0.2 to 12 m/s, with an optimal range of 2–5 m/s. The meter size can be selected according to the pipeline diameter to meet measurement accuracy requirements.
To minimize wear on the liner, the sensor’s flow velocity can be reduced, or it can be increased to prevent solid sedimentation. To avoid electrode wear due to wastewater with solid particles, larger-diameter sensors are typically chosen, maintaining a velocity below 3 m/s. Additionally, extending the straight pipe length upstream and downstream helps ensure symmetrical flow distribution.
For accurate measurement, Electromagnetic flow meters for industrial require full-pipe conditions. The ideal installation method is vertical mounting with upward fluid flow, allowing heavier particles to settle while grease floats away from the electrodes, ensuring reliable flow data. If vertical installation is not possible, the electrodes should be positioned along the horizontal axis to avoid air bubble interference.
Ultrasonic Flow Meter
Ultrasonic flow meters utilize various measurement methods, with Doppler and transit-time ultrasonic flow meters being the most commonly used types. The Doppler ultrasonic flow meter transmits sound waves into the flowing liquid and measures the Doppler frequency shift (fd) of the signal reflected from suspended particles or bubbles. This phase shift is used to determine the flow velocity.
Application Scope of Ultrasonic Flow Meter
Transit-time ultrasonic flow meters are suitable for clean, homogeneous fluids with minimal bubbles or suspended particles (impurity content <10g/L, particle size <1mm), such as municipal water and industrial process water.
Doppler ultrasonic flow meters are better suited for fluids containing reflectable particles or bubbles, such as industrial discharge water, untreated sewage, and process liquids with stable impurity content.
Application Features of Ultrasonic Flow Meter
Ultrasonic flow meters require minimal maintenance. Different models, including standard, high-temperature, explosion-proof, and wet-type variants, can accommodate different media, environments, and pipeline conditions. However, they require long straight pipe sections for installation, and precise sensor placement is crucial. In practice, Z-shape sensor installation with an inclination angle of less than 45° to the horizontal plane provides higher accuracy and stability.
Ultrasonic flow meters are particularly advantageous for large-diameter pipeline monitoring. Unlike other flow meters, their cost does not increase significantly with larger diameters.
Comprehensive Comparison of Flow Meters
Both Electromagnetic flow meters for industrial and ultrasonic flow meters can be used for industrial sewage monitoring. However, ultrasonic flow meters have stricter requirements for the measurement medium. For metering and billing industrial sewage discharge in industrial parks, Electromagnetic flow meters for industrial offer higher stability and accuracy compared to ultrasonic flow meters. Additionally, ultrasonic flow meters require long straight pipe sections, limiting their installation flexibility.
Electromagnetic flow meters for industrial are better suited for harsh environments and provide high measurement accuracy. Industrial-grade Electromagnetic flow meters for industrial are available in diameters ranging from a few millimeters to several meters, with the largest reaching 3 meters. They measure volumetric flow and are unaffected by viscosity, temperature, or density. Electromagnetic flow meters demonstrate excellent operational stability and accuracy.
The fluctuating characteristics of industrial sewage—such as varying discharge volumes, impurity levels, and corrosiveness—pose significant challenges to reliable and accurate flow measurement. After analyzing, comparing, and verifying the performance of several flow meters, it is concluded that electromagnetic flow meters are the optimal choice for industrial sewage flow monitoring.
