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.

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.

A multi-stage fluid pump system can include a first stage configured to provide a first pressure and a second stage configured to provide a second pressure. The pump system can be configured to prevent output of the second stage in a first stage mode such that only the first pressure is output from the first stage and second stage and to allow output of the second stage in a multi-stage mode such that there is a combined pressure output from the first stage and the second stage.

A back-to-back centrifugal pump comprising a pump inlet, a pump outlet, a pump shaft, a set of first stages, and a set of second stages in a back-to-back arrangement. Between the two sets of stages an intermediate crossover module is arranged. The first and second sets of stages comprise respective first outer diaphragms and second outer diaphragms. The outer diaphragms and the intermediate crossover module are stacked together and form a pump casing. The intermediate crossover module forms at least one axial transfer channel between the two sets of stages, and a fluid connection between the set of second stages and the pump outlet. The second diaphragms comprise each at least one peripherally arranged through aperture. The through apertures are aligned to form at least one passageway, which fluidly connects the axial transfer channel with a most upstream one of the impellers of the second set of stages.

A back-to-back centrifugal pump comprising a pump inlet, a pump outlet, a pump shaft, a set of first stages, and a set of second stages in a back-to-back arrangement. Between the two sets of stages an intermediate crossover module is arranged. The first and second sets of stages comprise respective first outer diaphragms and second outer diaphragms. The outer diaphragms and the intermediate crossover module are stacked together and form a pump casing. The intermediate crossover module forms at least one axial transfer channel between the two sets of stages, and a fluid connection between the set of second stages and the pump outlet. The second diaphragms comprise each at least one peripherally arranged through aperture. The through apertures are aligned to form at least one passageway, which fluidly connects the axial transfer channel with a most upstream one of the impellers of the second set of stages.

Systems and methods are provided for mitigating recirculation of backflow fluid through a fan. The fan includes a housing having a channel that extends from an inlet to an outlet of the housing. A rotor assembly is positioned within the channel and is configured to direct a fluid flow from the inlet to the outlet. The rotor assembly includes a hub, a plurality of fan blades, and a shroud disposed about a circumference of the fan blades, where a radial gap extends between the shroud and the housing. The radial gap is configured to receive a portion of the fluid flow from the outlet as backflow fluid. The rotor assembly also includes an inlet flange that is configured receive the backflow fluid from the radial gap and to direct the backflow fluid in a direction away from the inlet prior to discharge of the backflow fluid from the radial gap.

Systems and methods are provided for mitigating recirculation of backflow fluid through a fan. The fan includes a housing having a channel that extends from an inlet to an outlet of the housing. A rotor assembly is positioned within the channel and is configured to direct a fluid flow from the inlet to the outlet. The rotor assembly includes a hub, a plurality of fan blades, and a shroud disposed about a circumference of the fan blades, where a radial gap extends between the shroud and the housing. The radial gap is configured to receive a portion of the fluid flow from the outlet as backflow fluid. The rotor assembly also includes an inlet flange that is configured receive the backflow fluid from the radial gap and to direct the backflow fluid in a direction away from the inlet prior to discharge of the backflow fluid from the radial gap.

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.

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.

A multi-switch pump assembly is disclosed that facilitates switched flow and/or mixed flow from the pump assembly. The multi-switch pump assembly comprises a pump body, an electric motor, a rotating motor shaft, a first pump stage and impeller, and a second pump stage and impeller. The first pump stage includes a first inlet and first and second outlets disposed about the pump body. The second pump stage includes a second fluid inlet connected to a mix chamber. The mix chamber further connected to the second fluid outlet of the first pump stage. The second stage further includes a second and a third outlet disposed about the pump body. An actuator connected to a valve assembly is arranged to operate and place the valve assembly into at least a first, a second, a third and a fourth switched positions to direct fluid flow between the first and the second pump stages and the first, second, third and fourth fluid outlets.