An assembly structure of a multi-stage impeller and wheel housing for use in a submersible pump that includes a connecting seat having a drainage channel, shaft, intermediate unit which has a wheel housing, inner guide cover, and impeller. The wheel housing has a central partition plate, with an upper ring housing and lower ring canopy extending upward and downward, respectively, along the perimeter of the central partition plate. The intermediate unit has the upper ring housing connected to the canopy of the connecting seat by a swivel snap structure. A bottom unit has a bottom impeller and bottom wheel housing, which has a water suction port, a bottom plate and a bottom ring housing that extends upward along the perimeter of the bottom plate. A bottom ring canopy of an intermediate unit is connected by a rotating snap structure, and the bottom ring housing is pressed by a sealing ring.

A multistage centrifugal pump for conveying a fluid includes a pump housing with an inlet to receive the fluid and an outlet to discharge the fluid, a first stage impeller and a last stage impeller to convey the fluid from the inlet to the outlet, a shaft to rotate the first stage impeller and the last stage impeller about an axial direction, a suction chamber arranged upstream of the first stage impeller and in fluid communication with the inlet, a recirculation path for the fluid including a return opening and extending from the return opening to the suction chamber, the return opening located at or in the flow path downstream of the first stage impeller and upstream of the last stage impeller, and a flow control rod disposed in the recirculation path, the flow control rod to adjust a recirculation flow through the recirculation path into the suction chamber.

The present invention relates to a sealing system for a pump configured to pressurize a volatile liquid, such as liquid ammonia. The sealing system (2) includes a stuffing box (35) forming a barrier chamber (30) and a pump-side seal chamber (43), a mechanical seal (20) arranged in the barrier chamber (30), and a barrier-gas supply system (32) for supplying a barrier gas into the barrier chamber (30). The barrier gas has a pressure higher than a pressure of the volatile liquid in the pump-side seal chamber (43). The pump-side seal chamber (43) is located between an impeller (7) of the pump (1) and the mechanical seal (20). The barrier-gas supply system (32) includes a pressure control valve (50) configured to maintain a constant difference between pressure in the barrier chamber (30) and pressure in the pump-side seal chamber (43).

A mixed-flow impeller for an electric submersible pump can include a lower end and an upper end; a hub that includes a through bore that defines an axis; blades that extend at least in part radially outward from the hub where each of the blades includes a leading edge and a trailing edge; an upper balance ring that includes a radially inward facing balance chamber surface and a radially outward facing diffuser clearance surface; and an upper guard ring disposed radially outwardly from the upper balance ring where the upper guard ring includes an axially facing diffuser clearance surface that is disposed axially between the trailing edges of the blades and the upper end.

A mixed-flow impeller for an electric submersible pump can include a lower end and an upper end; a hub that includes a through bore that defines an axis; blades that extend at least in part radially outward from the hub where each of the blades includes a leading edge and a trailing edge; an upper balance ring that includes a radially inward facing balance chamber surface and a radially outward facing diffuser clearance surface; and an upper guard ring disposed radially outwardly from the upper balance ring where the upper guard ring includes an axially facing diffuser clearance surface that is disposed axially between the trailing edges of the blades and the upper end.

A liquid pressurizing apparatus, comprises a tank provided on a device installation surface for storing liquid so that a fluid level is located above the device installation surface; and a vertical pump including a suction port connected to the tank, multi-stage impellers arranged in a vertical direction, and a discharge port for discharging the liquid passing through the multi-stage impellers. The multi-stage impellers include a first stage impeller positioned at the lowest part of the multi-stage impellers and being configured such that the liquid from the suction port flows into the first stage impeller. The first stage impeller is disposed below the device installation surface.

A liquid pressurizing apparatus, comprises a tank provided on a device installation surface for storing liquid so that a fluid level is located above the device installation surface; and a vertical pump including a suction port connected to the tank, multi-stage impellers arranged in a vertical direction, and a discharge port for discharging the liquid passing through the multi-stage impellers. The multi-stage impellers include a first stage impeller positioned at the lowest part of the multi-stage impellers and being configured such that the liquid from the suction port flows into the first stage impeller. The first stage impeller is disposed below the device installation surface.

An arrangement for monitoring a centrifugal pump is provided. receiving the residual axial thrust of a centrifugal pump. The arrangement includes a load-relieving device configured to receive the residual axial thrust developed during pump operation, an axial bearing, and a sensor ring is associated with the axial bearing. The ring (10) is divided into segments having sensors at the segment dividing regions.

An arrangement for monitoring a centrifugal pump is provided. receiving the residual axial thrust of a centrifugal pump. The arrangement includes a load-relieving device configured to receive the residual axial thrust developed during pump operation, an axial bearing, and a sensor ring is associated with the axial bearing. The ring (10) is divided into segments having sensors at the segment dividing regions.

An electric submersible pump (ESP) assembly. The ESP assembly comprises an electric motor, a centrifugal pump, and a hybrid magnetic thrust bearing, wherein the hybrid magnetic thrust bearing is disposed inside the electric motor or disposed inside the centrifugal pump.