Patent ID: 7645127

Claim:
A peristaltic pump comprising: a pump housing having an inlet and an outlet; and a compressible pump tube having a fluid inlet end and a fluid outlet end, and positioned within the pump housing; and two or more occluding members rotatably mounted within the pump housing; and a pump tube track positioned within the housing; and where the pump tube is positioned along the pump tube track between the two or more occluding members and the pump tube track so that the occluding members occlude the pump tube during rotation and provide a flow of fluid through the pump tube; and the inlet end of the pump tube has a first constant internal diameter D extending to a position inside the pump housing where the pump tube then tapers down to a second constant internal diameter d, where the tapering occurs such that when the second occluding member rotates onto the second constant internal diameter d portion of the pump tube, the first occluding member continues to occlude a portion of the second constant internal diameter d, wherein when the first occluding member exits occlusion of the pump tube, a volume of compensating fluid is transported in the direction of first occluding member to compensate for a void created when the first occluding member exits occlusion; wherein the constant diameter d portion of the pump tube begins at a position just over 90 degrees within the pump tube housing.