Container assembly and pressure-responsive penetrable cap for the same

A container assembly comprising:

• a container defining an opening therein, the container comprising an outer surface and an inner surface accessible via the opening;
• and
• a penetrable cap configured to be capable of cooperating with the container to selectively close the opening, the penetrable cap comprising:
• an annular sealing portion extending into the container and having a radially-outward surface and a radially-inward surface, the radially-outward surface configured to sealingly engage, via abutting contact, the inner surface of the container, the radially-inward surface having a proximal edge and a distal edge, the distal edge being disposed substantially within the container;
• an annular substantially rigid portion operably engaged with and extending radially inward from the radially-inward surface of the annular sealing portion at a selected angle relative to the radially-inward surface of the annular sealing portion, the annular substantially rigid portion having a distal end;
• an annular transition portion operably engaged with and extending radially inward from the distal end of the annular substantially rigid portion, the transition portion being capable of flexing relative to the annular substantially rigid portion;
• a penetrable portion operably engaged with and extending radially inward from the annular transition portion, the penetrable portion being capable of elastically deforming about the annular transition portion towards the proximal edge of the annular sealing portion in response to a positive pressure generated within the container while the annular substantially rigid portion remains oriented at the selected angle relative to the radially-inward surface of the annular sealing portion such that the penetrable portion exerts a radially outward force that is transmitted by the annular substantially rigid portion to the radially-outward surface of the annular sealing portion so as to reinforce a seal between the radially-outward surface of the annular sealing portion and the inner surface of the container, and the penetrable portion having a thickness less than the annular substantially rigid portion to facilitate piercing by a piercing tool.