Magnetic current meter for open channel flow measurement

摘要

A magnetic current meter adapted to sense the flow of liquid through an open channel to produce a mean flow velocity signal that is independent of fluctuations in the level of liquid in the channel. The meter includes a tube of insulation material so positioned in the channel that its longitudinal axis is normal to the direction of flow. Disposed in the tube is a rod having a coil wound thereon, the coil being excited by a low-frequency alternating current to produce an external magnetic field. A pair of electrodes are mounted on opposite sides of the tube on the outer surface thereof whereby the flow of liquid which intercepts the external field induces a voltage signal in the electrodes proportional to the mean flow velocity. The height of the meter exceeds the depth of the channel and is higher, therefore, than the liquid level regardless of fluctuations therein.