Patent ID: 8187227

Claim:
A movable barrier device for separating parts of a breastpump, as to prevent contamination and convey a pressure change from one side of the barrier to the other, comprising: a barrier including a barrier circumference, a central axis, and a formed shape of convexity in an unassembled condition, wherein in an assembled condition said barrier is mounted within and separates parts of a housing and is compressed along said central axis through engagement with a part of said housing such that said barrier cannot reach said formed shape of convexity of said unassembled condition; a distended state to which said barrier moves in response to an air pressure change applied to one side of said barrier; and an initial state to which said barrier has a preset bias to return to, wherein said barrier achieves said initial state in response to the release of said pressure applied to said barrier; wherein in said initial state said barrier is in said assembled condition and is compressed along said central axis; wherein in said distended state, at least a part of said barrier passes along said central axis such that said barrier is in a position inverted from said formed shape of convexity.