TABLE OF CONTENTS Magnetic flowmeters depend on the principle that motion between a conductor (the flowing fluid) and a magnetic field develops a voltage in the conductor proportional to the velocity of the fluid.
Coils outside the pipe generate a pulsed DC magnetic field. Material to be measured flows through the meter tube, which is lined with a non-conductive material such as Teflon, polyurethane, or rubber. Measuring electrodes protrude through the liner and contact the fluid and sense the generated voltage.
The flowing fluid must be conductive, but there are very few other restrictions; most aqueous fluids are suitable. There are fewer Reynolds number limitations. The instrument is the full diameter of the pipe, so there is no pressure loss. A wide range of sizes are available from very small (1/8 inch, for example) up to 10 feet in diameter. The flowing material can be liquids, slurries and suspended solids, and there are minimum straight run requirements.
