Which medium cannot be measured by electromagnetic flowmeters?

Electromagnetic flowmeters are not universal; they are mainly unsuitable for low-conductivity media, media containing strong interfering components, and media exceeding the meter’s rated operating conditions.

1. Low-conductivity media

• Media with conductivity below the meter’s threshold (usually ＜5μS/cm) cannot be measured, such as pure water, distilled water, petroleum, gasoline, and diesel.
• Various organic solvents (e.g., ethanol, methanol, acetone) fail to form effective induced currents, resulting in weak or no signals.

2. Media containing strong interfering components

• Media with a large amount of magnetic particles will disrupt the magnetic field distribution inside the meter and damage the measurement principle.
• High-concentration suspensions (e.g., slurries with a lot of sediment or metal powder) are prone to clogging electrodes or causing uneven flow fields, and may wear the lining.

3. Media exceeding rated operating conditions

• Media with temperature and pressure beyond the meter’s calibrated range, such as high-temperature melts and high-pressure supercritical fluids, will damage the lining and electrodes.
• Highly corrosive media that exceed the tolerance of the electrode/lining. Without selecting special corrosion-resistant materials, component damage will occur, leading to inaccurate measurement.