Selection Principle of Electromagnetic Flowmeter?

Electromagnetic flowmeter selection to ensure measurement accuracy, improve production efficiency is of great significance. In the selection process, you need to fully consider the measurement medium, measurement range, pipe size, environmental factors and economic factors, in order to select the appropriate brand and model. At the same time, in the actual application should pay attention to the installation location, installation direction, maintenance and troubleshooting and other aspects of the problem, in order to ensure the normal operation of the electromagnetic flowmeter and measurement accuracy. However, different application scenarios on the electromagnetic flowmeter performance and parameter requirements are different, so the selection of the right type directly affects the use of the flowmeter.

1. Pipe and Installation Conditions

Generally, the caliber of the electromagnetic flowmeter should be consistent with the measured pipeline.

• Nominal Diameter (DN): Available from DN6 to DN2200. Select the size matching your pipeline.

• Flow Range: Ensure it meets your expected flow velocity (0.2 to 15 m/s).

• Straight Pipe Requirements: Typically needs ≥5D upstream and ≥2D downstream for accurate readings.

2. Lining and electrodes

The lining and electrodes of the electromagnetic flowmeter must be selected according to the chemical and physical properties of the measured medium (for example, when the medium flows, the temperature and pressure inside the pipeline must be lower than the temperature and pressure that the lining can bear). If the electrode and lining are not properly selected, the electromagnetic flowmeter will be damaged, even the lining will leak, and the flowmeter will not be able to measure the flow.

Electrodes: Choose based on chemical compatibility:

• 316L Stainless Steel: For general water applications

• Hastelloy C/Titanium/Tantalum: For strong acids, alkalis, and aggressive chemicals

• Platinum/Iridium: For highly corrosive and high-temperature applications

• Liner Material: Select based on the fluid type:

• PTFE (Teflon): For strong acids, alkalis, and high temperatures

• Rubber: For slurry, wastewater, and general industrial use

3. Fluid Characteristics

• Conductivity: The fluid must have a minimum conductivity of ≥2 µS/cm (e.g., water, wastewater, slurries, acids, and base

• Composition: Suitable for liquids with solid content, slurries, and corrosive chemicals, as there are no moving parts to get clogged.

• Temperature & Pressure: Ensure the flowmeter can handle the maximum process temperature (up to 180°C) and pressure ratings of your system.

4. Process Conditions

• Temperature Range: Standard: -20°C to +60°C; high-temp linings up to 180°C.

• Pressure Rating: Typically PN10–PN40, but some go up to PN100 for high-pressure lines.

• Explosion-Proof Certification (Ex d/Ex i): Required for hazardous areas.

5. Output & Communication

• Analog (4–20 mA, 0–10 V): Standard for PLC/DCS integration.

• Pulse/Frequency Output: For totalizing flow.

• Digital (HART, Modbus, Profibus, Foundation Fieldbus): Smart diagnostics and remote configuration.

6. Power Supply

• AC (220V/110V): Industrial fixed installations.

• DC (24V): Common for battery-powered or loop-powered systems.

• Intrinsic Safety (IS): For hazardous zones.

7. Compliance & Standards

Ensure the flowmeter meets relevant industry standards (ISO, CE, FDA, etc.) for your application, especially in food, beverage, or pharmaceutical industries.

8. Other features and compatibility

Communication protocol: Select the model that supports fieldbus or wireless communication protocol to adapt to the automation control system.

Protection level: Select the appropriate protection level (e.g. IP65, IP68) according to the harshness of the installation environment.