Submersible pumps are designed to function with both pump and motor submerged in the fluid to be pumped. The motor of this centrifugal pump is sealed in a way that prevents liquid from seeping in, protecting against short-outs.
Because the motors are below grade, submersible pumps cost less to install and allow for floor space to be better utilized. They also tend to have lower maintenance costs and are less noisy than pumps that have the motor mounted at grade. Since the impeller and casing are always submerged and there is no suction pipe with this pump, there is no concern for priming. Cavitation is also not a worry.
The components of a submersible pump depend on the type application and the pump’s installation. There are two main types of pumps: those that operate in a bored well and those that operate in a basin, sump, or wet well.
A bored well application usually includes a thin submersible motor located at the bottom of the pump. Just above the motor is an inlet screen and suction bell, which directs the fluid into the centrifugal pump stages. These are made up of impellers and diffuser bowls. Usually these submersible pumps are multi-stage, meaning they have more than one impeller and diffuser, to make them more effective at pumping at great depths.
Submersible pump flow range from fewer than 10 gallons per minute in a residential version, to several thousand gallons per minute for industrial, municipal or irrigation applications.
Iron construction is common in submersible pumps that handle clean water, dirty water or sewage. Meanwhile home well pumps and lighter duty sump or utility pumps are usually made from plastic, though some manufacturers make submersible pumps in more exotic alloys for corrosive and abrasive applications.
Some wastewater submersible pumps feature graining teeth on the impeller to chop or grind the waste. Often these pumps include a level control as part of the equipment. Some are sold in duplex arrangements that offer an alternator, which switches between motor when high levels are reached in the sump. This prevents both motors from starting too often, which could cause a motor starter to fail.
Submersible pumps are used in a range of applications including irrigation, dewatering, and oil production. They’re also commonly found used to pump wastewater that seep into homes and other buildings, as well as in ponds, industrial plants and municipal wastewater collection and treatment systems.
Written by PumpScout.com staff.