Submersible pumps, or sump pumps as they are often referred to, are a type of fluid transfer pump that is completely submerged into the liquid that it is designed to pump. With its hermetically sealed motor close coupled to the pump body, a submersible pump works by pushing the fluid to the surface rather than pulling it up. A benefit of the sump pump design is that because the pump is immersed in the liquid and the suction is flooded, pump cavitation is not an issue. It is much easier for a pump to pump or push a liquid than it is to suck or create a vacuum to draw liquid to the impeller.
Different impeller types are used depending on the fluid or solid content being pumped. For example should the submersible pump be handling sewage, a macerator impeller to obliterate solids or a vortex impeller to allow the solids to pass through the pump may be used.
Single stage submersible pumps are commonly used in applications concerning:
Water draining
Sewage pumping
Slurry pumping
Water transfer
Pond filters
Multistage submersible pumps however tend to be lowered down a borehole and utilised for:
Water extraction
Deep water well drilling
Offshore oil drilling rigs
Emergency deballasting
