US Patent 7556614 Separation assembly for drug delivery device

A separation assembly for initially keeping a first component separate from a second component includes a generally cylindrical body slidably supported within a container between the first and second components. The body includes a seal structure having an inner seal member that initially seals the first component from the second component. In response to a predetermined operating condition, the inner seal member allows the first component to flow through at least one flow path in the seal structure to mix with the second component. The body further includes a flow distributing member disposed adjacent the seal structure to evenly distribute the first component into the second component. The seal structure and the flow distributing member form a single unit.