In a rotary direct-drive single-stage or multi-stage centrifugal pump (1) for cryogenic liquids, having a pump housing (2) for the pump (1) and an electric drive motor unit (12) in a motor housing (10) serving as a pump drive, wherein a shaft (11) of the drive motor unit (12) is mounted on two roller bearings (20; 21), and wherein at least one roller bearing (20; 21) is an unlubricated roller bearing, the structural design of the centrifugal pump (1) should be kept as simple as possible. This is achieved in that at least a first communicating connection, in particular a direct connecting channel (16), is configured between the pressure side (D) in the pump housing (2) and the roller bearing (21) on the pump housing side for a diverted part (F.sub.A1) of the main conveying flow (F.sub.H) of the cryogenic pumped medium to the roller bearing (21), and that a second communicating connection is configured between the roller bearing (21) on the pump housing side and the suction side (S) for the diverted part (F.sub.A2) of the cryogenic pumped medium back to the suction side (S) in the main conveying flow (F.sub.H) of the cryogenic pumped medium, so that a circulation of the diverted part (F.sub.A1, F.sub.A2) of the cryogenic pumped medium is ensured between the pressure side (D) in the pump housing (2) and only the roller bearing (21) on the pump housing side.

In a rotary direct-drive single-stage or multi-stage centrifugal pump (1) for cryogenic liquids, having a pump housing (2) for the pump (1) and an electric drive motor unit (12) in a motor housing (10) serving as a pump drive, wherein a shaft (11) of the drive motor unit (12) is mounted on two roller bearings (20; 21), and wherein at least one roller bearing (20; 21) is an unlubricated roller bearing, the structural design of the centrifugal pump (1) should be kept as simple as possible. This is achieved in that at least a first communicating connection, in particular a direct connecting channel (16), is configured between the pressure side (D) in the pump housing (2) and the roller bearing (21) on the pump housing side for a diverted part (F.sub.A1) of the main conveying flow (F.sub.H) of the cryogenic pumped medium to the roller bearing (21), and that a second communicating connection is configured between the roller bearing (21) on the pump housing side and the suction side (S) for the diverted part (F.sub.A2) of the cryogenic pumped medium back to the suction side (S) in the main conveying flow (F.sub.H) of the cryogenic pumped medium, so that a circulation of the diverted part (F.sub.A1, F.sub.A2) of the cryogenic pumped medium is ensured between the pressure side (D) in the pump housing (2) and only the roller bearing (21) on the pump housing side.

An electrical submersible pump (ESP) and method for pumping fluid from a wellbore. The ESP has a motorized pump with an external rotor motor topology. The motorized pump fits into casing in the wellbore. The motorized pump includes a motor having a motor stator and a motor rotor. The motor stator is at a radial center of the motorized pump. The motorized pump has a centrifugal pump radially surrounding the motor stator. The centrifugal pump includes an impeller and a diffuser.

An electrical submersible pump (ESP) and method for pumping fluid from a wellbore. The ESP has a motorized pump with an external rotor motor topology. The motorized pump fits into casing in the wellbore. The motorized pump includes a motor having a motor stator and a motor rotor. The motor stator is at a radial center of the motorized pump. The motorized pump has a centrifugal pump radially surrounding the motor stator. The centrifugal pump includes an impeller and a diffuser.

In a cross section of a flow passage formed to conduct a flow of air from an inside/outside air box to an upper air passage of a scroll casing while the cross section of the flow passage is taken along an imaginary plane which includes an outer edge of an air guide plate and is parallel to a rotational axis of an impeller, a passage section, which is located on one radial side of a separation tube where a nose of the scroll casing is placed, is defined as a first opening section, and another passage section, which is located on an opposite radial side of the separation tube, which is opposite to the nose, is defined as a second opening section. A passage cross-sectional area of the second opening section is larger than a passage cross-sectional area of the first opening section.

In a cross section of a flow passage formed to conduct a flow of air from an inside/outside air box to an upper air passage of a scroll casing while the cross section of the flow passage is taken along an imaginary plane which includes an outer edge of an air guide plate and is parallel to a rotational axis of an impeller, a passage section, which is located on one radial side of a separation tube where a nose of the scroll casing is placed, is defined as a first opening section, and another passage section, which is located on an opposite radial side of the separation tube, which is opposite to the nose, is defined as a second opening section. A passage cross-sectional area of the second opening section is larger than a passage cross-sectional area of the first opening section.

A multistage pump for installation on a sea ground includes a common housing, a pump unit arranged in the common housing, a drive unit arranged in the common housing, and a coupling. The common housing includes a pump inlet and a pump outlet, the pump unit including a plurality of impellers to convey a compressible fluid from the pump inlet to the pump outlet, and a pump shaft, on which each impeller is mounted, each impellepr being a radial or semi-axial impeller. The drive unit includes a drive shaft to drive the pump shaft, and an electric motor configured to rotate the drive shaft about an axial direction. The coupling couples the drive shaft to the pump shaft. The pump unit conveys the fluid in a dense phase at the pump outlet, and at least two impellers of the plurality of impellers have a different specific speed.

An engine fuel or pump system includes a centrifugal pump having an impeller for imparting energy to an associated fluid for an associated downstream engine fuel system. A regenerative start stage is in selective fluid communication with the pump. And ejector includes an inlet that communicates with the pump outlet and an outlet that communicates with the pump inlet. Further, a regulator valve is interposed between the pump outlet and the regenerative start stage that selectively regulates associated flow from the regenerative start stage. The associated method include directing flow from the centrifugal pump to a regenerative start stage in order to supply an associated downstream flow circuit. During low speed starting, a portion of the flow from the regenerative start stage is provided to an ejector that recirculates to an inlet of the centrifugal pump. Once the centrifugal pump provides a predetermined level of at least one of the flow and pressure requirements of the associated flow circuit, the method includes terminating flow from the regenerative start stage.

An engine fuel or pump system includes a centrifugal pump having an impeller for imparting energy to an associated fluid for an associated downstream engine fuel system. A regenerative start stage is in selective fluid communication with the pump. And ejector includes an inlet that communicates with the pump outlet and an outlet that communicates with the pump inlet. Further, a regulator valve is interposed between the pump outlet and the regenerative start stage that selectively regulates associated flow from the regenerative start stage. The associated method include directing flow from the centrifugal pump to a regenerative start stage in order to supply an associated downstream flow circuit. During low speed starting, a portion of the flow from the regenerative start stage is provided to an ejector that recirculates to an inlet of the centrifugal pump. Once the centrifugal pump provides a predetermined level of at least one of the flow and pressure requirements of the associated flow circuit, the method includes terminating flow from the regenerative start stage.

Methods and devices for a self-contained device including a hydraulic motor and a hydraulic pump. Preferably, the motor is incorporated either within the interior of the pump, on the exterior of the pump, or a combination of the two. The pump increases the kinetic energy of the fluid by centrifugal means, and in some embodiments is a viscous impeller pump. Applications include building flow systems, industrial processes, and biological circulatory systems.