# US 2017/0284847 A1 · Method for operating a nuclear magnetic flowmeter and nuclear magnetic flowmeter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0284847 A1 - Document ID: US20170284847A1 - Status: Published application - Kind: A1 - Application number: 15/507,423 - Filed: 2015-07-02 - Published: 2017-10-05 - Earliest claimed: 2014-08-29 - Assignees: Krohne AG - Applicants: Krohne AG - Inventors: Cornelis Johannes Hogendoorn; Lucas Matias Ceferino Cerioni; Rutger Reinout Tromp; Marco Leendert Zoeteweij; Olaf Jean Paul Bousché - Web page: https://patentgrep.com/patent/US20170284847A1 ## CPC - G01F 1/716: using electron paramagnetic resonance [EPR] or nuclear magnetic resonance [NMR] - G01F 1/74: Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid - G01F 25/10: of flowmeters - G01N 24/08: by using nuclear magnetic resonance (G01N24/12 takes precedence) - G01R 33/307: {specially adapted for moving the sample relative to the MR system, e.g. spinning mechanisms, flow cells or means for positioning the sample inside a spectrometer} - G01R 33/50: based on the determination of relaxation times {, e.g. T1 measurement by IR sequences; T2 measurement by multiple-echo sequences} - G01R 33/56308: {Characterization of motion or flow; Dynamic imaging} - G01F 1/56: by using electric or magnetic effects (G01F1/66 takes precedence) - G01R 33/44: using nuclear magnetic resonance [NMR] (G01R33/24, G01R33/62 take precedence) - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## Abstract A method for measuring the flow rate of a multi-phase medium flowing through a measuring tube using a nuclear magnetic resonance flow meter can be used to measure the flow rate of a multi-phase medium in a simplified manner. For this purpose, a measuring device is used which implements, at the end of each pre-magnetization path, 2D tomography in the measurement tube cross-sectional plane with stratification in the z direction; the measurement tube cross-sectional plane is subdivided into layers that are thin compared to the measurement tube diameter; nuclear magnetic resonance measurements are carried out in every layer to determine measurement signals, using pre-magnetization paths of different lengths; the flow rates are measured in every layer based on the measurement signals; and the time is determined from the signal ratios of the amplitudes of the measurement signals in every layer. ## Claims ### Claim at position 1 1-17. (canceled) ### Claim 18 A method for determining the flow of a multi-phase medium flowing through a measuring tube with a nuclear magnetic flowmeter having a pre-magnetization device and a measuring device, the pre-magnetization device having at least two pre-magnetization sections with different known lengths L1, L2, . . . , Ln, the method comprising: using a measuring device that implements 2D tomography at the end of each pre-magnetization section in measuring planes perpendicular to a longitudinal axis of the measuring tube, identically dividing the measuring planes into voxels, the dimensions of the voxels being chosen such that only one phase of the medium flows in each voxel, carrying out nuclear magnetic measurement for determining measuring signals, determining the flow velocity of the medium in each voxel in each measuring plane, determining an average flow velocity of the medium for each voxel over all measuring planes from determined values of the flow velocity of each corresponding voxel of the individual measuring planes, determining a signal ratio of measuring signals of each corresponding voxel of the different measuring planes relative to one another, and with the known values for the lengths L1, L2 . . . Ln of the pre-magnetization sections, determining spin-lattice relaxation time T1 in each voxel using the signal ratios. ### Claim 19 (depends on 18) The method according to claim 18, wherein a respective hydrogen index HI in each voxel is determined with the respective spin-lattice relaxation time T1 and wherein using the spin-lattice relaxation time T1 and the hydrogen index HI, different phases of the medium and sections of the different phases are determined. ### Claim 20 (depends on 19) The method according to claim 19, wherein the flow rates are determined by integration over the different sections of the medium and multiplication with the respective flow velocities. ### Claim 21 (depends on 18) The method according to claim 18, wherein the nuclear magnetic measurement is implemented with a Carr Purcell Meiboom Gill (CPMG) sequence. ### Claim 22 (depends on 18) The method according to claim 18, wherein the velocity of the medium in every voxel in each plane is determined using the “convective decay” method. ### Claim 23 (depends on 18) The method according to claim 18, wherein amplitudes of the measuring signals at a time t=0 are used for determining the signal ratios. ### Claim 24 (depends on 18) The method according to claim 18, wherein a temporal course of the measuring signals is used for determining the signal ratio. ### Claim 25 (depends on 18) The method according to claim 18, wherein the at least two pre-magnetization sections are implemented by variable RF coils and wherein the measuring planes at the end of each pre-magnetization section are realized by different planes. ### Claim 26 (depends on 18) The method according to claim 18, wherein the at least two pre-magnetization sections are implemented by rotating magnetic arrangements and wherein the measuring planes at the end of each pre-magnetization section are realized in a single spatial plane. ### Claim 27 (depends on 18) The method according to claim 18, wherein the at least two pre-magnetization sections are implemented by RF coils transmitting spoil pulses and wherein the measuring planes at the end of each pre-magnetization section are realized in a single spatial plane. ### Claim 28 A method for determining the flow of a multi-phase medium flowing through a measuring tube with a nuclear magnetic flowmeter having a pre-magnetization device and a measuring device, the pre-magnetization device having at least two pre-magnetization sections with different known lengths L1, L2, . . . Ln, the method comprising: using a measuring device that implements 2D tomography at the end of each pre-magnetization section in a measuring tube cross sectional plane in a z direction, dividing the measuring tube cross sectional plane into thin layers in relation to the measuring tube diameter, carrying out nuclear magnetic measurements in every layer for determining measuring signals with at least two pre-magnetization sections of different lengths, determining the flow velocity in each individual layer using the measuring signals, and determining the spin-lattice relaxation time T1 time using the signal ratios of the amplitudes of the measuring signals in each layer. ### Claim 29 (depends on 28) The method according to claim 28, wherein the portions of the individual phases in the medium are determined using the absolute amplitudes of the measuring signals. ### Claim 30 (depends on 28) The method according to claim 28, wherein a water to liquid ratio for lower layers in the measuring tubes is determined layer for layer from bottom to top in the measuring tube, wherein a water to liquid curve depending on the position of the layer in the measuring tube is generated using the determined values, wherein a curve is extrapolated based on a last determined value over the entire measuring tube cross section, wherein expected measuring signal amplitudes for the upper layers in the measuring tube are calculated from the extrapolated curve, and wherein a gas volume portion in the upper layers is determined using a difference between the expected measuring signal amplitude and the actual measuring signal amplitude. ### Claim 31 Nuclear magnetic flowmeter for determining the flow of a medium flowing through a measuring tube, comprising: a pre-magnetization device and a measuring device, wherein the pre-magnetization device implements at least two pre-magnetization sections of differing lengths with the lengths L1, L2, . . . Ln, and wherein the measuring device is adapted to implement 2D tomography at the end of each pre-magnetization section either in a measuring plane perpendicular to a longitudinal axis of the measuring tube or in a measuring tube cross sectional plane in a z-direction. ### Claim 32 (depends on 31) Nuclear magnetic flowmeter according to claim 31, further comprising variable RF coils by which the different lengths L1, L2, . . . Ln, of the pre-magnetization section are implemented and wherein the measuring planes at the end of every pre-magnetization section fall in the area of the respective RF coil. ### Claim 33 (depends on 31) Nuclear magnetic flowmeter according to claim 31, further comprising rotating magnetic arrangements by which the different lengths L1, L2, . . . Ln of the pre-magnetization section are implemented and wherein the measuring planes at the end of each pre magnetization section are realized in a single spatial plane. ### Claim 34 (depends on 31) Nuclear magnetic flowmeter according to claim 31, further comprising variable RF coils which transmit spoil pulses by which the different lengths L1, L2, . . . Ln of the pre magnetization section are implemented, and wherein the measuring planes at the end of each pre-magnetization section are realized in a single spatial plane.