US Patent 7201165 Medication delivery apparatus and system having a visual indicator

A flow indicating system that includes a conduit that contains a substance, wherein the conduit defines a path along which the substance primarily flows and a viewing port attached to the conduit and the viewing port prevents substantially non-ambient atmosphere gases and substances from escaping therefrom and allows visualization of an internal space defined by the viewing port. A flow indicator that is positioned within the conduit so as to be viewed via the viewing port and is positioned so as to not to substantially interfere with a flow of the substance along the path.