FIELD: measurement technology.
SUBSTANCE: use for measuring longitudinal relaxation time in a current medium. Summary of invention consists in the fact that measuring the flow of the analysed fluid, the radio-frequency field amplitude, the frequency and amplitude of the constant magnetic field modulation, at which the amplitude of the nuclear magnetic resonance absorption signal reaches a maximum value, then measuring the optimum flow rate range, within which the amplitude of the current liquid nuclear magnetic resonance absorption signal is reduced by a fixed value determined by the signal / noise ratio, for the measured flow interval of the analysed fluid, the corresponding values of the longitudinal relaxation time are determined from the calibration curve of the signal amplitude, followed by similar measurements of flow rate of reference flowing fluid, amplitude of radio-frequency field, frequency and amplitude of modulation of constant magnetic field, at which the amplitude of the nuclear magnetic resonance absorption signal reaches a maximum value for the reference fluid with a known value of longitudinal relaxation time, the value of which is within the range of values of longitudinal relaxation time of the test sample, then reducing consumption of reference fluid to value q*, corresponding to the nuclear magnetic resonance absorption signal amplitude, reduced by half compared to the maximum value, constructing calibration curve of relative amplitude of absorption signal of nuclear magnetic resonance of flowing fluid at flow rate q* from longitudinal relaxation time in the range of values of longitudinal relaxation time of the analysed liquid, reference fluid is replaced by the analysed fluid and the amplitude of the absorption signal of nuclear magnetic resonance is measured relative to the maximum amplitude at the same values of flow rate q*, amplitude of radio-frequency field, frequency and amplitude of constant magnetic field modulation, which were fixed during measurement of signal amplitude reduced twice from reference fluid, method includes comparing the relative amplitude of the absorbance signal of nuclear magnetic resonance of the analysed fluid with the obtained calibration curve data and of the observed signal and based on a given functional dependence of signal amplitude on longitudinal relaxation, determining the value of said time for analysed flowing fluid.
EFFECT: high accuracy of measuring longitudinal relaxation time of nuclei in a flowing fluid.
1 cl, 7 dwg
