초록 ▼

An electromagnetic flowmeter for measuring the mean velocity of a fluid flowing through a duct is described. In one embodiment the electrodes are shaped to provide a uniform weighting function relating fluid velocity distribution over the duct cross section to flowmeter output voltage representative

An electromagnetic flowmeter for measuring the mean velocity of a fluid flowing through a duct is described. In one embodiment the electrodes are shaped to provide a uniform weighting function relating fluid velocity distribution over the duct cross section to flowmeter output voltage representative of mean velocity. Flowmeters are described in which using large insulated electrodes sensitivity is made independent of velocity profile by either ensuring that the applied magnetic field is uniform and the virtual current in the duct is two dimensional, or vice versa.

대표청구항 ▼

A magnetic flowmeter for measuring the flow rate of a fluid conducted through a pipe having a longitudinal axis Z, the fluid intercepting a magnetic field whose lines of flux are essentially parallel to a transverse axis X, which is normal both to axis Z and a diametric axis Y, said flowmeter furthe

A magnetic flowmeter for measuring the flow rate of a fluid conducted through a pipe having a longitudinal axis Z, the fluid intercepting a magnetic field whose lines of flux are essentially parallel to a transverse axis X, which is normal both to axis Z and a diametric axis Y, said flowmeter further comprising: A. a pair of electrode assemblies mounted on the pipe on opposite sides of the X axis in the region of the magnetic field; and B. a converter whose input terminals are connected to the electrode assemblies to produce a signal which is proportional to flow rate and is substantially immune to the influence of a non-axisymmetric flow profile, said electrode assemblies being out of contact with the fluid and being capacitively coupled thereto to detect a potential present on the fluid surface, the effective coupling capacitance of the assemblies decreasing in a manner substantially proportional to the cosine of an angle defined with respect to the Y axis.