METHOD FOR DETERMINING THE DIFFUSION COEFFICIENT IN SHEET CAPILLARY-POROUS MATERIALS Russian patent published in 2021 - IPC G01N13/00 G01N15/08 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measuring equipment and can be used to determine the diffusion coefficients in products from sheet capillary-porous materials in the paper, light and construction 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 investigated sheet material, then the test material is placed on a flat substrate made of a material impermeable to the solvent, the upper surface of the material is waterproofed, at the initial moment of time, the pulsed point moistening of the upper surface of the test item with a dose of solvent is carried out, then the change in time of the signal of the galvanic converter is measured at a given distance from the point of application of the pulse with a dose of the solvent, the moment of time of reaching the set value of the galvanic sensor signal is recorded and the diffusion coefficient is calculated, while the change in time of the signal of the additional galvanic sensor is measured at a different distance from the point of application of the pulse with a dose of the solvent, the moments of time τ₁ and τ₂ are fixed, at which the same signal values are achieved, respectively, of the first sensor E₁ and the second sensor E₂ from the range (0.7 - 0.9) E_e on the descending branches of the curves of signal changes in time of these two sensors, and the calculation of the coefficient diffusion is carried out according to the formula: , where r₁ and r₂ are the distance between the electrodes, respectively, of the first and second galvanic transducer and the point of exposure to the dose of the solvent on the surface of the controlled product; E_e is the maximum possible value of the sensor signal corresponding to the transition of the solvent from the region associated with the solid phase of the test material to the region of the free state.

EFFECT: improving the accuracy and speed of measuring the diffusion coefficient of solvents in sheet products made of capillary-porous materials.

1 cl, 1 dwg