A delivery system comprising a chamber (108) adapted to contain a substance in an interior volume of space formed within said chamber； an opening adapted for receiving said substance in said volume of space and for introducing said substance to a downstream path upon which said substance primarily flows along； an interface adapted for receiving said substance from said opening； and a flow indicator (138) that is positioned so as to not substantially interfere with a flow of said substance along said path, said flow indicator being hingedly connected relative to said interface so that said flow indicator is pivotable about a hinge axis.
