US Patent 7887505 Flow condition sensor assembly for patient infusion device

A device for delivering fluid to a patient including an exit port assembly adapted to connect to a transcutaneous patient access tool, a flow path extending from the exit port assembly, and a flow condition sensor assembly including a resilient diaphragm having opposing first and second surfaces. The first surface of the diaphragm is positioned against the flow path, and a chamber wall is positioned adjacent the second surface of the diaphragm and defines a sensor chamber against the second surface of the diaphragm. At least one sensor is arranged to provide a threshold signal when the second surface of the diaphragm expands into the chamber in response to at least one predetermined fluid flow condition occurring in the flow path.