METHOD FOR MEASUREMENT OF THE SPECIFIC SURFACE-AREA OF HIGHLY DISPERSE POWDERS BY GAS FILTRATION

A new method for measurement and calculation of the specific surface a rea by gas permeability of the compact powder layer is developed. Acco rding to this method, the values of the specific surface area of highl y disperse powders are invariant with respect to the degree of compact ness (porosity) in the layer and are proportional to their real values . The calculation formulas are transformed into the Kozeny-Carman form ula for coarse and medium disperse powders and viscous gas flow. The m ethod developed retains the practical advantages inherent in the Kozen y-Carman method (simplicity, reliability, express testing, and availab ility). The experimental data for air filtration under atmospheric pre ssure confirms the correctness of calculations. An instrument involvin g the automatic compensation of temperature variations in air viscosit y is developed. Automation of measurements and computer calculations s ignificantly enhance the accuracy of results and technological design of the instrument.