Patent ID: 6990848

Claim:
A method of nondestructively determining a property of a porous sample having a mass, said method comprising: evacuating a first vessel to a sub-atmospheric pressure; establishing a test pressure in a second vessel having the sample disposed therein, the test pressure being greater than the sub-atmospheric pressure; equalizing the pressures of the first and second vessels by opening a valve mechanism operably engaged between the first and second vessels, each of the first and second vessels thereby experiencing a pressure change, the pressure change in the second vessel exhibiting an initial pressure drop followed by a transition to an equalization pressure on a pressure vs. time curve; determining an envelope volume of the sample from a minimum pressure attained by the second vessel upon initial opening of the valve mechanism, the minimum pressure being related to the initial pressure drop; and determining an envelope density of the sample as a quotient of the mass and the envelope volume of the sample.