Submersible pumps are centrifugal, typically vertical, and can operate when immersed in the liquid to be pumped.
The motor and pump are made from a single block. As the motor has to work while immersed in the liquid to be pumped, it is made to be perfectly waterproof.
A submersible pump, however, is different from a submersed pump, which is designed to be installed at great depths. Submersed pumps, also commonly known as bore-hole pumps, are made to work constantly under head (installed below the minimum level of the bore) and typically guarantee a high outflow head (necessary for raising the water from the depths of the bores). They are therefore multistage.
Submersible pumps, instead, can operate even if only partially immersed, and are typically designed to empty flooded areas or tanks (that contain both clean and dirty water), for extracting water from pools, waterways, rainwater collection tanks and for irrigation.
How does it work?
It works in the same manner a centrifugal pump. When the liquid enters the body-pump, the rotor (powered by the motor) directs the fluid to the body-pump periphery because of the centrifugal force produced by the rotor speed: in this manner, the liquid stores an energy (potential) that is transferred into flow rate and head (or kinetic energy).
The typical heads of these machines are low because, as they mainly empty, the difference in level and the load losses to be regained are contained. Their efficiency is lower than the typical efficiency of centrifugal pumps because, in order to guarantee the possibility of working even with dirty water (that can also contain large solids), the play between the rotor and the volute can be very high.
Because of their applications, submergible pumps are usually moved by a float that can be incorporated in the pump or connected to it through the control panel.
- rotor that is retreated or with increased passages for pumping liquids that contain solid elements
- double shaft seal, with oil chamber in between. This means that maximum reliability can be guaranteed, even in the presence of “loaded” and particularly aggressive liquids, and it also guarantees protection from dry operation.