Patent ID: 7090093

Claim:
In a two-part container where the two-part container consists of an outer container and an inner container and wherein the inner container contains a partially-to fully-volatile fluid, and further wherein the two-part container is disposed in gas-filled surroundings, and wherein the inner container has walls that are impenetrable to diffusion to only a limited extent vis-à-vis the fluid it contains, and is collapsible, and wherein the outer container has walls that are impenetrable to diffusion and which walls are rigid, and wherein the outer container is sealingly connected to the inner container and a gas-filled intermediate space is present between the two containers, the improvement which comprises a pressure compensation device having at least one channel which communicates the gas-filled intermediate space between the outer container and the inner container with the gas-filled surroundings of the two-part container, which channel has a cross-sectional surface area with an equivalent diameter of between 10 μm and 500 μm, and the channel further is in length equal to between five thousand times and one tenth of the equivalent diameter of such channel.