METHOD FOR DETERMINING DIFFUSION COEFFICIENT IN SHEET ORTHOTROPIC CAPILLARY-POROUS MATERIALS Russian patent published in 2023 - IPC G01N13/00 G01N15/08 

FIELD: measuring technology.

SUBSTANCE: invention can be used in the study of mass transfer processes and to determine the diffusion coefficients of solvents in orthotropic capillary-porous materials in paper, light, construction and other industries. The method for determining the diffusion coefficient of solvents in sheet orthotropic capillary-porous materials consists in the fact that a uniform initial content of the solvent distributed in the solid phase is created in the test sheet material, then the test material is placed on a flat substrate made of a solvent-impermeable material, the upper surface of the material is waterproofed; in the initial moment of time, the test material is pulse-moistened in a straight line by a moving solvent source of constant productivity in a given direction of the orthotropic material, the electrodes of two galvanic converters are made in the form of straight segments and placed on both sides of the pulsed moistening line on straight lines parallel to the pulsed moistening line and at different distances r₁ and r₂ from it, fix the moments of time τ₁ and τ₂, at which the same values of the signals of the first sensor E₁ and the second sensor E₂ are achieved, respectively, from the range (0.7 - 0.9) E_e on the descending branches of the curves of changes in the signals over time of these two sensors and the diffusion coefficient is calculated. The diffusion coefficient is measured under the condition that in the experiment the maximum signal E_max2 is reached, which is more distant from the line of application of the impulse action of the second galvanic sensor, equal to (0.75 - 0.95) E_e, and the desired diffusion coefficient is calculated with the values of the signals of both sensors E₁ and E₂, approximately equal to (E_max2 - 0.05 E_e), where E_e is the maximum possible value of the sensor signal corresponding to the transition of the solvent from the region of the material under study associated with the solid phase to the region of the free state.

EFFECT: increased accuracy of measuring the diffusion coefficient of solvents in sheet orthotropic capillary-porous materials.

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