Patent ID: 7563076

Claim:
A wellbore pumping system comprising: a motor, wherein said motor has an operating speed; a pump coupled to said motor, wherein said pump has a volumetric displacement; a fluid end coupled to said pump, wherein said fluid end is operable to draw a fluid from an input and provide the fluid to an output that is in fluid communication with a wellbore; a control system operable to regulate said motor and said pump in order to provide the fluid to the output at a selected pressure and flow rate within a continuous range of pressures and flow rates between a peak horsepower output and a peak torque output of said motor; and a displacement controller coupled to said pump and operable to vary the volumetric displacement of said pump, wherein said displacement controller comprises a hydraulic cylinder and a coupler operable to axially translate a rotating shaft, wherein the axial translation of the rotating shaft varies a stroke of the pump.