Capacitance type electromagnetic flowmeter

摘要

A capacitance type electromagnetic flowmeter which is capable of measuring flow rates of fluid without being affected by the flow velocity distribution. When the flow tube of the flowmeter is an open conduit, the measurement is made without being affected by variations in the liquid level. The flowmeter comprises a flow tube insulated at least on an inner surface thereof; an exciting means for applying a magnetic field to the fluid, and a pair of detecting electrodes disposed in the flow tube, which are electrically insulated from the fluid and extend at right angles to the flow tube axis and magnetic field. The length of the electrodes is proportional to the cosine of an angle between a line normal to the wall of the flow tube and an axis perpendicular to both axes of the flow tube and magnetic field. Where a conduit is used, the liquid has a free surface, and currents produced from the detecting electrodes are converted by a current-to-voltage converter into voltage signals.