Rigid packaging using gas-permeable membrane

Method for producing a rigid container, which provides for selective separation of an emitted off-gas from solid particulate container contents while maintaining hermetic-sealing integrity of such contents and separated off-gas prior to opening the container, comprising

• (A) providing an elongated configuration rigid container body formed from flat-rolled sheet metal which is impervious to ambient atmosphere,
• such container body:
• (i) defining a centrally-located axis for such rigid container, and
• (ii) having an elongated side wall symmetrically disposed in relation to such centrally-located axis for the container;
• (B) providing end closure means formed from material impervious to ambient atmosphere so as to be capable, in combination with such container body, of forming a hermetically-sealed container for such contents;
• (C) defining an enclosed chamber within such container by
• (D) providing an imperforate membrane film, which is permeable to a selected off-gas emitted by container contents,
• (E) positioning such film between such end closure means and such container body means in fixed transverse relationship to such centrally-located axis, with
• such film being intermediate such end closure means and such container contents so as to provide for receiving and retaining such off-gas while such container is hermetically-sealed.

Packaging procedure for solid particulate contents, which emit off-gases including carbon dioxide during storage, comprising the steps of

• providing a container body with a side wall defining a centrally-located axis for a container,
• such container body being fabricated from rigid packaging material which is impervious to ambient atmosphere and capable of withstanding an internal level of pressure selected from the group consisting of a vacuum level and an inert gas purging pressure level, for use in hermetically-sealed packaging of container contents;
• providing an end closure structure, made from rigid flat-rolled sheet metal which is impervious to ambient atmosphere and capable of withstanding such a selected level of pressure and capable of combining with such container body to provide a hermetically-sealed container;
• providing for an internal chamber space, within such a hermetically-sealed container, which can be separated from remaining space for container contents;
• providing an imperforate membrane film which is permeable to carbon dioxide emitted by such container contents;
• establishing such membrane film in fixed transverse relationship to such centrally-located axis separating such internal chamber space from remaining space for container contents, with
• such membrane film, in combination with such internal chamber space, forming an enclosed chamber for receiving and holding such emitted carbon dioxide after passage through such membrane so as to be held in separated relationship from such container contents;
• and
• hermetically-sealing such container including such enclosed chamber.