How to Choose an Electromagnetic Flow Meter: 5 Practical Tips from Industry Experts

Selecting the right electromagnetic flow meter is not just a technical decision—it directly affects measurement accuracy, system stability, and long-term operating costs. With a wide range of specifications, materials, and brands available, making the correct choice requires a clear understanding of both process conditions and instrument performance.

This guide outlines five practical, field-proven tips to help you choose an electromagnetic flow meter that truly fits your application.
 

Tip 1: Clearly Define the Measured Medium and Operating Conditions

Before comparing models or brands, start with your actual process conditions.

Medium Characteristics

• The fluid must be conductive (typically ≥ 5 μS/cm).

• Check for corrosive properties, abrasive solids, or entrained air.

• Corrosive fluids require special electrode materials (e.g. platinum, Hastelloy) and chemical-resistant liners (PTFE, PFA).

Temperature and Pressure

• Liner material must match operating temperature:

  • Rubber liner: ≤ 80°C

  • PTFE liner: ≤ 180°C

• Ensure the rated pressure of the meter exceeds pipeline pressure (common ratings: 1.6 MPa, 4.0 MPa).

Pipe Diameter

• Typical sizes range from DN10 to DN3000.

• For very large pipelines, insertion-type electromagnetic flow meters can significantly reduce cost.

Tip 2: Match Core Performance Parameters Accurately

Correct parameter selection ensures reliable and repeatable measurement.

Accuracy Class

• Standard industrial accuracy: ±0.5%

• High-precision applications: ±0.2% to ±0.3%

• Water treatment usually accepts ±0.5%, while dosing or custody transfer may require higher accuracy.

Flow Velocity Range

• Recommended range: 0.1 to 15 m/s

• Extremely low velocities (<0.1 m/s) may affect measurement stability.

Signal Output and Communication

• Standard output: 4–20 mA

• Optional digital communication: RS485, HART, PROFIBUS, Modbus

• Choose based on control system integration needs.

Power Supply

• 220 VAC for standard installations

• 24 VDC or battery-powered options for remote or hazardous locations

Tip 3: Select the Right Electrodes, Liners, and Protection Levels

Material selection is critical for durability and measurement stability.

Electrode Materials

• 304 / 316L Stainless Steel: clean water, mild liquids

• Hastelloy C: strong acids, chlorides

• Platinum-Iridium: oxidizing acids (e.g. nitric acid)

• Tungsten Carbide: abrasive slurries

Liner Materials

• Neoprene Rubber: cost-effective, abrasion-resistant

• Polyurethane Rubber: excellent wear resistance

• PTFE / PFA: strong acid and alkali resistance

Protection and Explosion Rating

• Protection class:

  • IP65: splash-proof

  • IP68: suitable for long-term submersion

• Explosion-proof certification (e.g. Ex d IIC T6) is required for chemical and oil & gas environments.

Tip 4: Consider Installation and Maintenance Convenience

Improper installation is one of the most common causes of inaccurate measurement.

Meter Configuration

• Compact type: easy maintenance, limited space

• Remote type: suitable for high temperature, vibration, or hard-to-access locations

Installation Orientation

• Horizontal installation: electrodes must be horizontal to avoid air bubbles

• Vertical installation: flow direction should be bottom to top

Straight Pipe Requirements

• Upstream: ≥ 5 DN

• Downstream: ≥ 3 DN

• Avoid installing near pumps, valves, or elbows.

Grounding

• For non-metal pipes or poorly grounded systems, grounding rings or grounding electrodes are essential.

Tip 5: Evaluate Brand Reputation and Technical Support

A reliable brand ensures long-term stability and after-sales support.

Certifications and Standards

• ISO 9001 quality system

• Explosion-proof approvals (ATEX, IECEx)

• Third-party calibration certificates

Brand Options

• International manufacturers: Endress+Hauser, KROHNE, Yokogawa, Siemens

• High-value Chinese brands: SGAIC, Aister, suitable for standard industrial applications

Cost Consideration

• Avoid choosing solely based on price.

• Consider service life, failure rate, maintenance cost, and technical support availability.

Additional Features Worth Considering

• Empty pipe detection and alarm functions

• Electrode contamination diagnostics

• Low-power design for battery-powered installations

• Special certifications for food, beverage, or pharmaceutical use (e.g. 3A approval)

• Custom solutions for extreme temperature or pressure applications

Conclusion: Make an Informed and Application-Oriented Choice

Choosing an electromagnetic flow meter is not about finding the most expensive or most famous product—it is about selecting the right configuration for your specific process conditions. By clearly defining your application, matching key parameters, selecting appropriate materials, and working with reliable suppliers, you can achieve accurate measurement, stable operation, and long-term cost efficiency.

A well-selected electromagnetic flow meter is not just an instrument—it is a long-term investment in process reliability and performance.

If you need professional advice or product recommendations, feel free to contact us anytime.