Abstract: An electromagnetic flowmeter whose primary includes a flow tube through which the fluid to be metered is conducted to intersect a magnetic field and thereby induce a voltage therein that is transferred to electrodes to produce an electrode signal as a function of flow rate, which signal includes a noise voltage. The electrode signal is applied to the input amplifier of a secondary whose output is fed to one input of a summing stage, the output of which is fed to a range amplifier that yields a test voltage, the input and range amplifiers producing offset voltages. To compensate for the noise and offset voltages, a compensation voltage is derived from the test voltage and applied to the other input of the summing stage. This compensation voltage is produced only when the test voltage exceeds a predetermined threshold value.

Abstract: An electromagnetic flowmeter capable of measuring fluids having any degree of conductivity, including fluids having dielectric properties. The fluid to be measured is fed through a dielectrically-lined flow tube to intersect a transverse magnetic field, thereby inducing a voltage in a pair of planar detecting electrodes disposed within the dielectric lining. Each detecting electrode and an associated planar shielding electrode are unitized in an assembly wherein the electrodes are embedded in a liner segment formed of rigid dielectric material, connections to the electrodes being made by means of a coaxial line extending radially through an opening in the flow tube, the line having an outer conductor attached to the shielding electrode and an inner conductor attached to the detector electrode, the space between the line conductors being filled with the same dielectric material as that of the segment.

Abstract: An electromagnetic flowmeter system capable of measuring fluids having any degree of conductivity, including fluids having dielectric properties. The fluid to be measured is conducted through a dielectrically-lined flow tube to intersect a transverse magnetic field produced by an electromagnet, thereby inducing a voltage in a pair of planar electrodes mounted within the dielectric lining, each electrode being provided with a driven shield. The electromagnet is excited by a direct voltage which is periodically interrupted to produce a periodic steady state field whereby unwanted in-phase and quadrature components are minimized.