METHOD FOR DETERMINING POROSITY PARAMETERS FOR MATERIALS Russian patent published in 2006 - IPC G01N15/08 

FIELD: measuring equipment engineering, possible use for estimating quality of various porous materials.

SUBSTANCE: measuring barrel 1 is connected to controlled material 2, forming a measuring chamber 3. measuring chamber 3 is vacuumized. By means of pressure indicator 6 and time indicator 7, changes of pressure in chamber 3 are recorded in time. By means of signal amplifier 9, signal about change of pressure increment in chamber 3 is amplified and each following pressure increment is recorded by memorizing device 10. comparison of following pressure increment with previous one and signal transformer 12 is performed, gas pressure increment in chamber 3 is transformed to increment of gas volume, and coefficients of filtering (K_f), penetrability (K₀), diffusion (D), solubility(Henry constant - K_H) and porosity (P) are determined from mathematical expressions: solubility coefficient: - filtering coefficient: - porosity coefficient: - gas penetrability coefficient: diffusion coefficient: where or where V_u - volume of gas, flowing during time unit t_u at pressure P_u into measuring chamber, m³; F - area of controlled material, limited by measuring chamber, m²; R₀ - gas constant, Joule/(kg·K); μ - dynamic viscosity coefficient, Pa·s; P_c, t_c - pressure (Pa) and time (s) in measuring chamber, appropriate for transition from Knudsen to lamellate gas flow mode; P_u, t_u - current value of pressure (Pa) and rime (s), t_u>t_c; P_a - atmospheric pressure, Pa; ν - kinematic viscosity coefficient, m²/s; l - thickness of researched material, m; d - diameter of material, limited by measuring chamber, m.

EFFECT: increased precision.

1 dwg