Patent ID: 8523540

Claim:
A fluid pump system comprising an electrical drive unit and a rotary pump comprising a rotatable shaft and a drive element attached to the shaft for causing flow within a process fluid; the electrical drive unit comprising an electrical stator and an electrical rotor attached to the shaft; the electrical stator being disposed within a first casing and the rotary pump and the electrical rotor being disposed within a second casing; wherein the first casing contains a first lubricant fluid and the second casing contains a second lubricant fluid sealed from the process fluid and the arrangement being such that the electrical stator is disposed adjacent to the electrical rotor, wherein the fluid pump system comprises a second external fluid cooling circuit comprising an inlet section connected to the second casing and an outlet section connected to the second casing; at least one second impeller causing a flow of the second lubricant fluid from within the second casing through the second external cooling circuit.