Electric Submersible Pumps

A submersible pump, which has a tightly sealed motor attached to the body, is a device used for pushing fluid to the surface, from the ground up. They are also referred to as electric submersible pump and are more efficient that jet pumps. The whole device, as its name goes, is submerged in the fluid or water to be pumped.

An electric submersible pump is a multistage centrifugal pump that operates in a vertical position. Although its operational and constructional design underwent a constant evolution over the past few years, their basic operational function remains the same.

After being subjected to extreme centrifugal forces caused by the high rotational speed of the impeller, produced liquids lose their kinetic energy in the diffuser where a conversion of kinetic to pressure energy occurs. This is the primary operational mechanism of radial and mixed flow submersible pumps.

The pump shaft is fitted to the gas divider or the protector by a mechanical coupling underneath the pump. Well fluids enter the pump through an inlet screen and are hoisted by the pump stages.

Other parts include the radial bushings distributed along the length of the shaft giving radial foundation to the pump shaft running at high rotational speeds. An alternative thrust bearing consumes part of the axial forces coming from the pump but most of those forces are absorbed by the thrust bearing of the protector.

Submersible pumps are can be used in many applications. Individual-stage pumps are used for sewage pumping, general industrial pumping, drainage, and slurry pumping. They can also be used for aquarium filters.

Multi-stage submersible pumps are commonly lowered down a borehole and used for abstraction of fluids in oil wells as well as water wells. Attention to details to the type of electric submersible pump is needed when using certain types of liquids.

Electric submersible pumps that are commonly used on board Navy ships cannot be used for de-watering contaminated flooded areas. These use a 440-volt A/C motor that runs on a small centrifugal pump.

The pumped liquid is swirled around the motor for it to cool down. There is a chance that the gas will leak into the pump and causing short circuit that might result to fire, damaging the pump. Hot water and flammable liquids should be avoided and dealt with great caution.

Submersible pumps are used in oil production to provide an efficient form of artificial lift, able to operate across a wide range of flow rates and depths