A submersible well fluid pump has diffusers non-rotatably mounted in a pump housing. A drive shaft rotates an impeller between each of the diffusers. A bearing is positioned between and in abutment with two of the diffusers. An annular recess encircles an outer wall of the bearing. A wave spring has undulations with inward protruding indentations in contact with a base of the recess and outward protruding indentations in engagement with an inner wall of the housing. The wave spring is split and radially compressed between the base of the recess and the housing inner wall.

A submersible well fluid pump has diffusers non-rotatably mounted in a pump housing. A drive shaft rotates an impeller between each of the diffusers. A bearing is positioned between and in abutment with two of the diffusers. An annular recess encircles an outer wall of the bearing. A wave spring has undulations with inward protruding indentations in contact with a base of the recess and outward protruding indentations in engagement with an inner wall of the housing. The wave spring is split and radially compressed between the base of the recess and the housing inner wall.

A multistage centrifugal pump for conveying a fluid includes a pump housing with an inlet and an outlet, first and second stage impellers for conveying the fluid from the inlet to the outlet, and a shaft for rotating each impeller about an axial direction. Each impeller is a double suction impeller, having a first suction side, a second suction side for receiving the fluid and a discharge side for discharging the fluid. The discharge side of the first stage impeller includes two separate exits, a first exit for discharging the fluid into a first crossover line, and a second exit for discharging the fluid into a second crossover line. The first crossover line is in fluid communication with the first suction side of the second stage impeller, and the second crossover line is in fluid communication with the second suction side of the second stage impeller.

A multistage centrifugal pump for conveying a fluid includes a pump housing with an inlet and an outlet, first and second stage impellers for conveying the fluid from the inlet to the outlet, and a shaft for rotating each impeller about an axial direction. Each impeller is a double suction impeller, having a first suction side, a second suction side for receiving the fluid and a discharge side for discharging the fluid. The discharge side of the first stage impeller includes two separate exits, a first exit for discharging the fluid into a first crossover line, and a second exit for discharging the fluid into a second crossover line. The first crossover line is in fluid communication with the first suction side of the second stage impeller, and the second crossover line is in fluid communication with the second suction side of the second stage impeller.

A submersible well fluid pump has diffusers non-rotatably mounted in a pump housing. A drive shaft rotates an impeller between each of the diffusers. A bearing is positioned between and in abutment with two of the diffusers. An annular recess encircles an outer wall of the bearing. A wave spring has undulations with inward protruding indentations in contact with a base of the recess and outward protruding indentations in engagement with an inner wall of the housing. The wave spring is split and radially compressed between the base of the recess and the housing inner wall.

A submersible well fluid pump has diffusers non-rotatably mounted in a pump housing. A drive shaft rotates an impeller between each of the diffusers. A bearing is positioned between and in abutment with two of the diffusers. An annular recess encircles an outer wall of the bearing. A wave spring has undulations with inward protruding indentations in contact with a base of the recess and outward protruding indentations in engagement with an inner wall of the housing. The wave spring is split and radially compressed between the base of the recess and the housing inner wall.

A dual stage grinder pump (10) includes a housing (12) with a liquid inlet (20) and an outlet (26). An impeller (36) includes first impeller vanes (52) on a first axial side, and second impeller vanes (60) on a second axial side. A grinder (40) operates to reduce the size of suspended solids in the liquid that enters the pump inlet. Liquid passes from the inlet to a first fluid passage (30) and is acted upon by first vanes of the impeller in a first stage, and then passes through a second fluid passage (72). Liquid is acted upon by the second vanes of the impeller in a second stage and is passed through a third fluid passage (88) to the outlet.

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.

The invention provides a centrifugal pump, distinctive in that the pump comprises two or more stages; the last stage in the direction of flow has been adapted so that it provides a larger equilibrium droplet size than the upstream stages. Method of designing the pump and use of the pump.