A submersible well pump assembly has upper and lower seal sections connected between the pump and a motor. The seal sections have drive shafts with thrust runners that engage thrust bearing bases. The upper drive shaft will undergo a limited amount of downward movement toward the lower drive shaft in response to wear of the upper thrust bearing base. A spring between ends of the drive shafts transfers a portion of the down thrust on the upper drive shaft to the lower drive shaft prior to the limited amount of downward movement of the upper drive shaft toward the lower drive shaft being reached. A rigid stop member in the coupling transfers down thrust directly from the upper drive shaft to the lower drive shaft, bypassing the spring, only after the limited amount of downward movement of the upper drive shaft toward the lower drive shaft has been reached.

A submersible well pump assembly has upper and lower seal sections connected between the pump and a motor. The seal sections have drive shafts with thrust runners that engage thrust bearing bases. The upper drive shaft will undergo a limited amount of downward movement toward the lower drive shaft in response to wear of the upper thrust bearing base. A spring between ends of the drive shafts transfers a portion of the down thrust on the upper drive shaft to the lower drive shaft prior to the limited amount of downward movement of the upper drive shaft toward the lower drive shaft being reached. A rigid stop member in the coupling transfers down thrust directly from the upper drive shaft to the lower drive shaft, bypassing the spring, only after the limited amount of downward movement of the upper drive shaft toward the lower drive shaft has been reached.

A system and a method for starting a rotor of an implantable blood pump are described. For example, a blood pump system includes a rotary motor having a stator and a rotor. The rotor has permanent magnetic poles for magnetic levitation of the rotor, and the stator has a plurality of pole pieces arranged circumferentially at intervals. The blood pump system includes a controller configured to control a start phase of the rotor, wherein the start phase is prior to the rotor being positioned in a predefined geometric volume for pumping blood and wherein the start phase includes performing a rotation of the rotor by an angle larger than an angle corresponding to a quarter of an angular distance between two neighboring magnetic poles of the rotor.

A system and a method for starting a rotor of an implantable blood pump are described. For example, a blood pump system includes a rotary motor having a stator and a rotor. The rotor has permanent magnetic poles for magnetic levitation of the rotor, and the stator has a plurality of pole pieces arranged circumferentially at intervals. The blood pump system includes a controller configured to control a start phase of the rotor, wherein the start phase is prior to the rotor being positioned in a predefined geometric volume for pumping blood and wherein the start phase includes performing a rotation of the rotor by an angle larger than an angle corresponding to a quarter of an angular distance between two neighboring magnetic poles of the rotor.

A water cooled inverter is disclosed herein. More specifically, disclosed is a water cooled inverter for attachment to a water pump housing that defines a water chamber therewithin, the water cooled inverter comprising a pump seal plate, including a sealing wall that has a pump seal plate aperture therethrough, the pump seal plate aperture configured to receive a motor shaft to allow an impeller coupled to the motor shaft to propel water within the water chamber, and an inverter assembly, wherein the pump seal plate thermally couples the inverter assembly to the water chamber.

A centrifugal pump for pumping fluid includes a volute having an upstream inlet that receives the fluid and a downstream outlet that discharges the fluid. An impeller is disposed in the volute and comprises a plurality of impeller vanes. The impeller is configured to rotate about an axis of rotation so that the plurality of impeller vanes accelerates the fluid radially outwardly from the upstream inlet to the downstream outlet. The impeller is further configured to discourage air-lock of the centrifugal pump by expelling air away from the upstream inlet as the impeller rotates about the axis of rotation.

A centrifugal pump for pumping fluid includes a volute having an upstream inlet that receives the fluid and a downstream outlet that discharges the fluid. An impeller is disposed in the volute and comprises a plurality of impeller vanes. The impeller is configured to rotate about an axis of rotation so that the plurality of impeller vanes accelerates the fluid radially outwardly from the upstream inlet to the downstream outlet. The impeller is further configured to discourage air-lock of the centrifugal pump by expelling air away from the upstream inlet as the impeller rotates about the axis of rotation.

A centrifugal electric pump includes a motor casing, containing in turn, an electric motor with a transmission shaft and a hydraulic part. The transmission shaft is connected to at least one impeller present disposed in the hydraulic part. The motor casing is provided internally with a housing in which the electric motor is accommodated. An external surface of the housing defines a cooling surface adapted to be flowed over by pumping liquid that arrives from the hydraulic part. The cooling surface is provided with a covering that is resistant to oxidation. The covering is constituted by a hydraulically isolating sheath, which is contoured to affect the cooling surface.

A centrifugal electric pump includes a motor casing, containing in turn, an electric motor with a transmission shaft and a hydraulic part. The transmission shaft is connected to at least one impeller present disposed in the hydraulic part. The motor casing is provided internally with a housing in which the electric motor is accommodated. An external surface of the housing defines a cooling surface adapted to be flowed over by pumping liquid that arrives from the hydraulic part. The cooling surface is provided with a covering that is resistant to oxidation. The covering is constituted by a hydraulically isolating sheath, which is contoured to affect the cooling surface.

A current generator for a swimming system may include multiple entrainment pumps that discharge a flow of water into a pool. The entrainment pumps may each have a nozzle, a venturi and an entrainment inlet. In use, the flow of water from the nozzle into the venturi causes water at the entrainment inlet to flow into the venturi along with water from the nozzle. Each entrainment pump is arranged such that the fluid that flows out of the venturi passage is directed within a main passage, and the flow from multiple venturis may be combined and may be directed at least partially against the force of gravity before that fluid is directed out of the main passage outlet and into the pool. In at least some implementations, the fluid flows for at least one foot between the venturi and the main passage outlet.