FIELD: measuring equipment.
SUBSTANCE: invention relates to measurement equipment and can be used in investigation of mass transfer processes in capillary-porous materials for determination of diffusion coefficients of solvents in construction materials and structures. Method of determining the diffusion coefficient in solid articles from orthotropic capillary-porous materials involves creating in the analyzed sample a uniform initial content of a solvent distributed in a solid phase, bringing the flat surface of the sample into contact with a solvent dose source, pulse dampening in the specified direction of the analyzed orthotropic material along a straight line with a constant solvent constant flow source, performing electrodes of a galvanic converter in the form of rectilinear sections and their arrangement on both sides of a pulse humidification line on direct parallel lines of pulse moistening and located at the same specified distance from it, measuring time variation of EMF of galvanic converter, wherein measurement of diffusion coefficient is carried out under condition of achievement in experiment of maximum signal of galvanic sensor Emax, which is 0.75–0.95 of maximum possible value of given signal Ee, corresponding to transition of solvent from region associated with solid phase of analyzed material into free state region, fixing time moments τ1 and τ2, at which identical values of signals of galvanic sensor E1 and E2 are achieved from range (0.7–0.9) Ee respectively, on the ascending and descending branches of the signal variation curve in time, and the diffusion coefficient is calculated by the formula: D=r02(τ2-τ1)/[4τ2τ1ln(τ2/τ1)], where r0 is distance between electrodes of galvanic converter and point of action of solvent dose on surface of controlled article.
EFFECT: high accuracy of measuring diffusion coefficient of solvents in solid articles from orthotropic capillary-porous materials.
1 cl, 1 dwg, 1 tbl
