Patent ID: 6766682
Filing Date: 2004-07-27
Classification: G01N

Abstract:
A method for determining the gas transmission rate through a barrier material comprising the steps of:a) providing a sealable box within which at least a portion of said material is placed; b) sealing said material within said box to form a test gas chamber extending from one side of said material and a measurement chamber extending from the opposite side of said material, said measurement chamber encompassing a sealed area of said material sufficient to allow uniform diffusion of a gas through said material; c) continuously metering a set quantity of said gas into and out of said test gas chamber by controlling a rough vacuum to determine the concentration of said gas in said test gas chamber as a function of time; d) drawing a vacuum in said measurement chamber by a molecular vacuum pump to a final vacuum of at least about 2Ã—10âˆ’4 Torr; e) providing a mass spectrometer in direct valved communication with said measurement chamber; and f) determining the transmission rate of said gas through said material by partial pressure readings of said mass spectrometer.