Patent ID: 8353864

Claim:
A method for detecting an upstream occlusion in an infusion apparatus having a flexible tube, wherein the tube opens to fill with fluid from an upstream fluid source and is collapsed by an armature to pump fluid to a downstream patient, the method comprising: applying a first force to the armature to collapse the tube; sensing the collapsing of the tube, wherein sensing the collapsing of the tube includes sensing a first position of the armature with the tube collapsed; applying a second force to the armature to allow the tube to open; sensing the opening of the tube, wherein sensing the opening of the tube includes sensing a second position of the armature with the tube open; measuring the time required for the tube to move from a collapsed state to an open state; and detecting an upstream occlusion when the time to move the tube from the collapsed state to the open state is greater than a reference time, wherein measuring the time required for the tube to move from the collapsed state to the open state includes measuring an elapsed time between sensing the first position of the armature and sensing the second position of the armature, and wherein detecting an upstream occlusion includes detecting an upstream occlusion when the elapsed time is greater than the reference time.