METHOD FOR DETERMINING DIFFUSION COEFFICIENT IN SHEET 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 in products made of sheet capillary-porous materials in paper, light, construction and other industries. The method for determining the diffusion coefficient in sheet 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, at the initial moment time, pulse point moistening of the upper surface of the tested product with a dose of solvent is carried out, then the change in time of the signals of two galvanic converters located at different distances r₁ and r₂ from the point of application of the pulse with a dose of solvent is measured, the moments of time τ₁ and τ₂ are fixed, 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 point 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.

2 cl, 3 dwg, 1 tbl