| 摘要 |
PROBLEM TO BE SOLVED: To correct zero-point errors, without exactly correcting the span and making the flow of objective fluid zero exact. SOLUTION: The electromagnetic flowmeter comprises the measurement tube 1; a pair of electrodes 2a, 2b for detecting the electromotive force generated by the magnetic field impressed on the fluid and the flow of the fluid; a pair of exciting coils 3 for impressing asymmetric magnetic field to the plane, including the electrodes 2a, 2b perpendicular to the axis of the measurement tube; the zero-point correction part 51 for extracting the v×B component by eliminating theδA/δt component detected by the letcrodes 2a, 2b (Here,δrepresents partial differentiation symbol) from the resultant electromotive force ofδA/δt component independent of the flow velocity of the fluid and the v×B component, depending on the flow velosity; the span correcting part 52 for extractingδA/δt component from the combined power and for eliminating the fluctuation factor of the span that is the factor to the magnitude of the flow velocity V of the v×B component, on the basis of theδA/δt component; and the flow output part 6 for computing the flow of the fluid from the v×B component with the fluctuation factor eliminated. COPYRIGHT: (C)2006,JPO&NCIPI
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