Patent ID: 8337470

Claim:
An apparatus for flow control, comprising: a housing defining first and second chambers, wherein the second chamber is in fluid communication with a body lumen of a patient; a wall disposed between said first and second chambers, said wall defining a single central hole and a plurality of arc-shaped openings, said arc-shaped openings encircling the central hole; and a valve, comprising: a canopy disposed within said first chamber and configured to permit fluid flow through said arc-shaped openings from the second chamber to the first chamber when an infusion pressure in the first chamber reaches a predetermined threshold; and a duck-bill stem extending through the central hole and configured to permit fluid flow from the first chamber to the second chamber when a negative pressure is applied in the first chamber wherein the duck-bill stem has a substantially conical shape, and wherein each of an inner diameter, an outer diameter, and a wall thickness of said duck-bill stem decrease substantially linearly from a distal opening of the duck-bill stem to a proximal end of the duck-bill stem.