| 摘要 |
A nuclear magnetic resonance flowmeter measuring flow rate of the organic portion only in the flow of mixtures made of aqueous, organic and gaseous components comprises a flow passage disposed intermediate two magnetic poles providing a constant transverse magnetic field generally perpendicular to the central axis of the flow passage, which flow passage extends through a first coil generating a first alternating axial magnetic field parallel to the central axis of the flow passage and oscillating at the Larmor frequency, which first alternating magnetic field is generated in pulses with a frequency substantially greater than the inverse of the spin-lattice relaxation time of the aqueous component in the mixture, and through a second coil downstream to the first coil, that generates a second alternating axial magnetic field oscillating at the Larmor frequency, which second alternating magnetic field is generated in pulses at a frequency substantially greater than the inverse of the spin-lattice relaxation time of the organic component in the mixture. The first alternating magnetic field completely scrambles the nuclei magnetic moments of the aqueous component only, while the second alternating magnetic field completely scrambles the nuclei magnetic moments of the aqueous component and completely or partially scrambles the nuclei magnetic moments of the organic component. A radio frequency receiver including an antenna coil disposed at a midsection of the second coil detects the nuclear magnetic resonance radio frequency emission from the organic component of the mixture, wherein the intensity of the NMR emmission increases as the velocity of the organic component increases. The velocity of the organic component in the mixture as well as the mass or volume fraction of the organic component in the mixture is determined from the intensity of the NMR RF emission from the organic component.
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