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Submersible electric motor driven inducer equipped centrifugal pump units, especially suitable for the pumping of cryogenic fluids or fluids at their boiling point, and capable of maintaining full flow under low submergence conditions are provided by disconnecting the inducers from co-rotation with

Submersible electric motor driven inducer equipped centrifugal pump units, especially suitable for the pumping of cryogenic fluids or fluids at their boiling point, and capable of maintaining full flow under low submergence conditions are provided by disconnecting the inducers from co-rotation with the main impeller shaft while still retaining the main shaft for support and are powered by a source in the unit such as a slip coupling, a hydraulic turbine driven by pumpage from the pump impeller, or a separate electric motor. These power sources drive the inducer at speeds slower than the pump impeller to develop the desired suction head for the impeller without drawing excessive power or producing undesirable thrusts and reduce pump-out time for the last few feet of cargo. A hydraulic or magnetic clutch coupling with the main electric motor drive may be used in combination with the turbine power source for the inducer to start the pumping action. The inducers preferably have two spiral blades and are preferably driven at about one-half to two-thirds the speed of the main impeller.

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In a submersible electric motor driven centrifugal pump unit with an inducer in the pump inlet ahead of the pump impeller supported on a hollow motor driven impeller shaft, the improvements of a second shaft extending through said hollow shaft coupled to said inducer, a turbine in the top end of sai

In a submersible electric motor driven centrifugal pump unit with an inducer in the pump inlet ahead of the pump impeller supported on a hollow motor driven impeller shaft, the improvements of a second shaft extending through said hollow shaft coupled to said inducer, a turbine in the top end of said unit driven by pumpage from the impeller and driving said second shaft at a lower speed than said hollow shaft, and a coupling driving the inducer from the hollow shaft during start-ups of the unit.