Abstract: A method for determining a liquid portion of a flowing medium with a nuclear magnetic flowmeter includes: generating a gradient magnetic field in a measuring tube volume of the flowmeter; exposing the medium to the gradient magnetic field and a magnetic field generated by a magnetizing device of the flowmeter; generating and irradiating an excitation signal into the magnetized medium for exciting nuclear magnetic resonances therein; measuring nuclear magnetic resonances excited by the excitation signal in the magnetized medium as a measuring signal; determining frequencies of the nuclear magnetic resonances in the measuring signal; assigning the determined frequencies to positions along a first gradient direction in the measuring tube volume; assigning the nuclear magnetic resonances at the positions to liquid and gaseous portions of the medium; and determining a liquid portion of the medium in the measuring tube volume from the positions of the nuclear magnetic resonances.

Abstract: A method for operating a nuclear-magnetic flowmeter in which, when determining a velocity of the medium through a measuring tube, the dependency on properties or the state of a medium is at least reduced. The method exciting a first volume of the magnetized medium flowing at a first velocity within a first measuring section to nuclear-magnetic resonances and a first signal sequence is formed characterizing the nuclear-magnetic resonances of the medium in the first volume, and then, exciting a second volume of the magnetized medium flowing at a second velocity within the first measuring section is excited to nuclear-magnetic resonances and a second signal sequence is formed characterizing the nuclear-magnetic resonances of the medium in the second volume. A quotient sequence is determined from each of the first and second signal sequences, and the first velocity and/or the second velocity is/are determined using the quotient sequence.

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.

Abstract: A method for operating a nuclear magnetic flowmeter for determining the flow of a slug flow medium flowing through a measuring tube, with which “tuning” parameters and “matching” parameters are set for a slug zone a film zone, reflected power is measured over time. If the reflected power in a system set for slug zone is low for the slug zone and high for the film zone and if the reflected power in a system set for film zone is low for the film zone and high for the slug zone, relative dwell time of the slug zone and the film zone in the RF coil and the relative frequency of the slug zones and film zones in the flowing medium are determined using the reflected power with a jump in the value of the reflected power from a high value to a lower value used to trigger measurement initiation.

Abstract: A method for operating a nuclear magnetic flowmeter in which the necessary time for determining a longitudinal relaxation time constant of the medium is reduced in comparison to the prior art by at least one nuclear-magnetic measuring process being carried out on a magnetized medium in the measuring tube. The at least one nuclear-magnetic measuring process includes an inversion pulse and acquisition sequences, each acquisition sequence beginning at a starting point in time in respect to the at least one nuclear-magnetic measuring process and has an activating pulse, a first waiting interval, a first refocusing pulse, an echo interval with a duration, a second refocusing pulse, a second waiting interval and a deactivating pulse. An echo signal is measured in the echo interval, and a longitudinal relaxation time constant of the medium is determined using the echo signals.

Abstract: A nuclear magnetic flowmeter (1) for determining the flow of a medium flowing through a measuring tube (2), having a magnetic field generator (3) having permanent magnets for generating a magnetic field interfusing the medium over a magnetic field section LM, having a pre-magnetization section LVM located within the magnetic field section LM and having a measuring device also located in the magnetic field section LM including a coil-shaped antenna (4) with the length L1 serving as a measuring antenna. At least one coil-shaped antenna (5) is provided in the pre-magnetization section LVM for generating a pulse or pulse sequence spoiling the magnetization of the medium in the direction of the magnetic field.

Abstract: A method for operating a nuclear-magnetic flowmeter in which, when determining a velocity of the medium through a measuring tube, the dependency on properties or the state of a medium is at least reduced. The method exciting a first volume of the magnetized medium flowing at a first velocity within a first measuring section to nuclear-magnetic resonances and a first signal sequence is formed characterizing the nuclear-magnetic resonances of the medium in the first volume, and then, exciting a second volume of the magnetized medium flowing at a second velocity within the first measuring section is excited to nuclear-magnetic resonances and a second signal sequence is formed characterizing the nuclear-magnetic resonances of the medium in the second volume. A quotient sequence is determined from each of the first and second signal sequences, and the first velocity and/or the second velocity is/are determined using the quotient sequence.

Abstract: A method for operating a nuclear magnetic flowmeter in which the necessary time for determining a longitudinal relaxation time constant of the medium is reduced in comparison to the prior art by at least one nuclear-magnetic measuring process being carried out on a magnetized medium in the measuring tube. The at least one nuclear-magnetic measuring process includes an inversion pulse and acquisition sequences, each acquisition sequence beginning at a starting point in time in respect to the at least one nuclear-magnetic measuring process and has an activating pulse, a first waiting interval, a first refocusing pulse, an echo interval with a duration, a second refocusing pulse, a second waiting interval and a deactivating pulse. An echo signal is measured in the echo interval, and a longitudinal relaxation time constant of the medium is determined using the echo signals.

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.

Abstract: A method for operating a nuclear magnetic flowmeter for determining the flow of a slug flow medium flowing through a measuring tube, with which “tuning” parameters and “matching” parameters are set for a slug zone a film zone, reflected power is measured over time. If the reflected power in a system set for slug zone is low for the slug zone and high for the film zone and if the reflected power in a system set for film zone is low for the film zone and high for the slug zone, relative dwell time of the slug zone and the film zone in the RF coil and the relative frequency of the slug zones and film zones in the flowing medium are determined using the reflected power with a jump in the value of the reflected power from a high value to a lower value used to trigger measurement initiation.

Abstract: A nuclear magnetic flowmeter (1) for determining the flow of a medium flowing through a measuring tube (2), having a magnetic field generator (3) having permanent magnets for generating a magnetic field interfusing the medium over a magnetic field section LM, having a pre-magnetization section LM located within the magnetic field section LM and having a measuring device also located in the magnetic field section LM including a coil-shaped antenna (4) with the length L1 serving as a measuring antenna. At least one coil-shaped antenna (5) is provided in the pre-magnetization section LVM for generating a pulse or pulse sequence spoiling the magnetization of the medium in the direction of the magnetic field.