| 摘要 |
PROBLEM TO BE SOLVED: To precisely measure the flow by correctly span correcting automatically, regarding the automatic span correction technology for correcting the coefficient relating with the component of flow speed oriented from the flow of the fluid to be measured among the electromotive forces detected by the electrodes. SOLUTION: The magnetic flowmeter comprises: a measurement tube 1 in which the fluid to be measured flows through; electrodes 2a, 2b for detecting the electromotive force generated by the magnetic field impressed on the fluid and the flow of the liquid; an excitation coil 3 for exciting the fluid with non-symmetrically modified magnetic field to a plane PLN which includes the electrodes 2a, 2b and is perpendicular to the axial direction of the measurement tube; a signal converter 5 for extracting theΔA component from the resultant electromotive force of theΔA component detected by the electrodes 2a, 2b, independent from the flow speed (herein,ΔA represents partial differential of t by A) and an electromotive force v×B component oriented from the flow speed of the fluid; and a flow output part 6 for calculating the flow of fluid from the result eliminated with the variation factor based on the extractedΔA component eliminating the variation factor of the span being the coefficient of the magnitude of the flow speed V of the v×B component in the resultant electromotive force. COPYRIGHT: (C)2006,JPO&NCIPI
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