PROCESS DETERMINING ACTIVE POROSITY OF MATERIALS Russian patent published in 2002 - IPC

FIELD: measurement technology. SUBSTANCE: in correspondence with proposed process closed air-tight spaces are formed in front of sample and behind it. Harmonic vibrations of gas with variable frequency are formed in closed air-tight space in front of sample, changes of amplitude of pressure of gas in front of sample and behind it are measured, difference of amplitudes is computed and three values of frequency is found from condition of equality of amplitudes. Active porosity is determined by relations of amplitudes in closed space behind sample and in front of it which correspond to specific values of frequencies. EFFECT: increased accuracy of measurement of porosity of materials. 2 dwg