Environmental Engineering Reference
In-Depth Information
Check
valve
Electrical
connection
Drop pipe
Inlet screen
Bowls and
impellers
Inlet screen
Electric
motor
figure 3.14 Submersible pump.
3.3.9.1 Submersible Pumps
The submersible pump is, as the name suggests, placed directly
in the wet well or groundwater well. It uses a waterproof electric motor
located below the static level of the well to drive a series of impellers. In
some cases, only the pump is submerged, while in other cases the entire
pump-motor assembly is submerged. Figure 3.14 illustrates this system.
3.3.9.1.1 description
The submersible pump may be either a close-coupled centrifugal
pump or an extended-shaft centrifugal pump. If the system is a close-cou-
pled system, then both motor and pump are submerged in the liquid being
pumped. Seals prevent water and wastewater from entering the inside of
the motor, protecting the electric motor in a close-coupled pump from
shorts and motor burnout. In the extended-shaft system, the pump is sub-
merged and the motor is mounted above the pump wet well. In this situa-
tion, an extended shaft assembly must connect the pump and motor.
3.3.9.1.2 applications
The submersible pump has wide applications in the wastewater
treatment industry. It generally can be substituted in any application of
other types of centrifugal pumps; however, it has found its widest appli-
cation in distribution or collector system pump stations.
