SOLVENTS DIFFUSION COEFFICIENT IN THE SHEET CAPILLARY-POROUS MATERIALS DETERMINING METHOD

摘要

FIELD: measuring equipment.;SUBSTANCE: invention relates to the measuring equipment and can be used in the mass transfer processes studying and to determine the solvents diffusion coefficients in articles from the sheet capillary-porous materials in paper, light, construction and other industries. Solvents in sheet products from capillary-porous materials diffusion coefficient determining method consists in creation of uniform initial content of distributed in solid phase substances in analyzed sample, bringing the sample flat surface into contact with the solvent dose pulse dot source, measuring the galvanic transducer signal time variation when its electrodes are located on that surface along the concentric circle relative to the solvent dose exposure point and calculating the unknown diffusion coefficient, fixing the time moments τ₁ and τ₂, at which the galvanic transducer signals E₁ and E₂, respectively, equal values are achieved on the signal change curve in time ascending and descending branches, making 0.7–0.9 of this signal maximum possible value E_e, corresponding to the solvent transition from the associated with the material under study solid phase region into the free state region, and the solvent introduced dose at the pulse action and the required diffusion coefficient are calculated by formulas: where ρ₀ is the analyzed sample density in dry state; U_p is the solvent equilibrium concentration in the analyzed sample upon contact with the solvent saturated vapors at the given temperature; r₀ is the distance between the galvanic transducer electrodes and the solvent action point on the article surface; h is the sheet material thickness.;EFFECT: technical result is increase in the solvents in sheet products of capillary-porous materials diffusion coefficient measuring accuracy and speed.;1 cl, 1 dwg, 1 tbl