Patent ID: 7004010

Claim:
Method for determining the penetration rate of a gaseous substance into a closed package made of a package material, characterised in that the method comprises: flushing the package with an inert gas for a sufficiently period to ensure that the interior of the package contains only small amounts of the gaseous substance, and then seal off the package against the ambient atmosphere, exposing the closed package to ambient atmosphere containing a known quantity of the gaseous substance for a first specified time period, when reaching the end of the first time period, determine a first concentration of the gaseous substance within the package at the end of the first time period, allowing the package to be exposed to the ambient gas for a second time period, when reaching the end of the second time period, determine a second concentration of the gaseous substance within the package at the end of the second time period, and employ the two measured concentrations of the gaseous substance in the equation ⅆ V Oxygen ⅆ t = V ⁢ ⁢ κ p otm ⁢ ( p 0 - p 1 ) ⁢ e - κ ⁡ ( t - t 1 ) to predict the penetration rate of the gaseous substance into the closed package as a function of time.