Patent ID: 8292594

Claim:
A pumping system comprising: a reciprocating positive-displacement pump comprising: a hemispherical rigid chamber wall; a rigid limit structure; a flexible membrane attached to the rigid chamber wall and interposed between the rigid chamber wall and the rigid limit structure, such that the flexible membrane and rigid chamber wall together define a pumping chamber and the flexible membrane and the rigid limit structure together define an actuation chamber, and wherein the rigid limit structure is constructed and positioned to limit movement of the membrane and limit the maximum volume of the pumping chamber; an inlet for directing flow through the rigid chamber wall into the pumping chamber; an outlet for directing flow through the rigid chamber wall out of the pumping chamber; and an actuation system that alternately provides either a positive or a negative pressure to the actuation chamber; wherein the actuation system includes: a reservoir containing a control fluid at either a positive or a negative pressure, and a valving mechanism for controlling a flow of control fluid between the actuation chamber and the reservoir; an actuation-chamber pressure transducer for measuring a pressure of the actuation chamber; and a controller that receives pressure information from the actuation-chamber pressure transducer and controls the valving mechanism, wherein the controller determines a first measure of an integral of pressure information from the actuation-chamber pressure transducer as a function of time during a stroke, and uses said first measure in determining the presence of an aberrant flow condition.