MAGNETIC FLOWMETER

A flowmeter (10) for measuring the velocity of a fluid has a means (50) for producing a magnetic field transverse to the direction (A) of fluid velocity thereby inducing a voltage potential in the fluid. The magnetic field producing means could use either electromagnets or permanent magnets. Two primary electrodes (40) in electrical contact with the fluid, spaced apart along a first line transverse to the direction of the magnetic field and transverse to the direction of the fluid velocity sense the induced voltage potential and a background voltage across the fluid. Two secondary electrodes (42) in electrical contact with the fluid, spaced apart along a plane parallel to the direction of the magnetic field and parallel to the direction of the fluid velocity sense the background voltage across the fluid. A signal processing means (72), responsive to the primary and secondary electrodes, generates a velocity signal representative of the magnitude of the velocity of the fluid. A magnetic sensor means (52) senses the magnetic of the magnetic field across the fluid and means in the signal processing means corrects the velocity signal for any fluctuations in the magnetic field.