A submersible pump is a kind of centrifugal pump that is designed to work with the entire pump as its motor completely submerged in the liquid to be pumped. The motor in a submersible pump is sealed to prevent the liquid being pumped from seeping through the motor, which would short out the motor.
A submersible pump does not use a motor above grade, which helps in saving floor space and reducing overall installation costs. These types of pumps tend to be less costly to maintain and also keep noise levels to a minimum. Additionally, they do not require any priming and present less concerns about cavitations because the casing and impeller are always fully submerged and they don’t have a suction pipe.
How They Work
The particular type of pump and motor that consist of a submersible pump will usually depend on the application as well as installation details. There are two general types of the submersible pump, those that operate inside a bored well and ones that operate inside a wet well, sump or basin.
The type of submersible pump that operates inside a bored well usually comes with a thin/flat submersible motor at the base of the pump. Right above the motor is a suction bell and inlet screen that directs the liquid into the centrifugal pump sections consisting of impellers and diffuser cavities. These pumps are usually multi-stage, which means that they have multiple impellers and diffuser cavities and are appropriate for pumping liquids from very deep wells.
The flow rates for a submersible pump ranges from less than 10 gallons per minute (gpm) for residential applications, to several thousands gpm for industrial, municipal or irrigation application. Some types of the submersible pump meant for wastewater include grinding teeth on the impeller to chop waste. They often include a level control to prevent the motor from starting too often, which might damage the motor starter.
A submersible pump can handle clean and dirty water or even sewage, and most are constructed from iron. Light duty sump or utility pumps and home well pumps are often constructed from plastic, but some pump types meant for abrasive and corrosive applications are made from more exotic alloys.
Applications
The submersible pump has a wide range of applications. The kinds that operate in a well are used for irrigation, drinking water supply, dewatering as well as in oil production. The other kinds that operate in pits, sumps, basins or wet wells are usually used for pumping wastewater from groundwater that may seep into buildings or equipment and floor drains in buildings. They are also common in municipal wastewater treatment and collection plants.
