| 摘要 |
An electromagnetic flowmeter includes a measuring tube ( 1 ) through which a fluid to be measured flows, electrodes ( 2 a , 2 b) which detect an electromotive force generated by a magnetic field applied to the fluid and the flow of the fluid, an exciting coil ( 3 ) which applies, to the fluid, a time-changing magnetic field asymmetrical to a plane (PLN) which includes the electrodes ( 2 a , 2 b) and is perpendicular to the axial direction of the measuring tube, a signal conversion unit ( 5 ) which extracts a ∂A/∂t component from the resultant electromotive force of the electromotive force based on the ∂A/∂t component irrelevant to the flow velocity of the fluid and the electromotive force based on a vxB component originating from the flow velocity of the fluid, which are detected by the electrodes ( 2 a , 2 b), and a flow rate output unit ( 6 ) which removes a variation factor for a span as a coefficient applied to the magnitude (V) of the flow velocity of the vxB component in the resultant electromotive force, on the basis of the ∂A/∂t component, and calculates the flow rate of the fluid from the result obtained by removing the variation factor.
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