A magnetic flow meter primarily measures which type of fluid?

Magnetic flow meters operate on the principle of electromagnetic induction, which fundamentally requires that the fluid being measured is conductive. This means that these meters rely on the fluid’s ability to conduct an electric current to generate a measurable voltage when the fluid flows through a magnetic field.

For a magnetic flow meter to function effectively, it needs a minimum level of electrical conductivity, which is typically found in liquids like water, slurries, and other conductive fluids. The operation of the meter does not depend on the fluid's viscosity or whether it is a gas or non-conductive. In fact, using a magnetic flow meter for non-conductive fluids (like oils or certain types of chemicals), or gaseous fluids would not yield accurate measurements, as there would be no induced voltage for measurement.

Thus, the essence of magnetic flow meters lies in their design and principle of operation, making conductive fluids the correct context for their application.