What is the Difference Between Centrifugal Pump and Submersible Pump?

A submersible pump is infact a centrifugal pump. It works along the same principle of drawing water into vaacum(low pressure suction region) created by a rotating impellor (blades). The kinetic energy of the blades is transferred to the fluid and this energy is made to convert into pressure energy as a function of the shape of the pump casing.

The most common type of centrifugal pump that one can closely relate to is the End Suction Centrifugal pump.

These pumps installed on the surface unlike a submersible pump require manual priming that is filling the suction or inlet pipe of the pump with water before operating as the pump cannot drive water into it due to the presence of air column that encroaches into the pump casing when inoperative.

The submersible pump is a configuration in which the motor used to drive the pump along with the pump remains sealed and submerged underwater. This allows the pump to work without the need for priming as the unit is submerged in water.

Here are the main point between those two types of slurry pumps

• Normally a centrifugal pump has suction and a delivery side. Atmospheric suction for water service has a limitation of approximately 26 feet at sea level and reduces as you live at higher elevations.
• But in Many applications the suction varies a lot. When a pump is fitted in a well the water levels vary considerably. In such situation is a better option over a Jet Pump.
• Submersible pump is designed with a hermetically sealed motor with no moisture ingress even if it is fully submerged in water. and its electrical connection is also completely water proof with electrical connection done though a gland, filled with water repellent jelly or Grease.
• In a Submersible pump, the suction is always flooded, meaning the water is completely covering the suction port.
• The pump is usually connected to the motor by extendable shaft which is kept as close as possible , But as far as possible just above expected high water mark. But if water level exceeds even then and motor getting submerged will not create any problems.
• In open wells intake port guarded with a wire mesh to prevent ingress of leaves, Fish, frogs and, Toads etc,
• This avoids the the Suction side limitations of Centrifugal Pumps such as Air lock, foot valve, Cavitation etc.
• As the pump sometimes needs to be kept well below the ground, a lifting hook, tackle and chain are provided to lift the motor for servicing.

The installation difference

• Centrifugal Water pump: Above ground installation.
• Submersible Water Pump: Below Surface submerged installation.

Also, we have to said that, of course a submersible pump is a type of centrifugal pump but with a sealed motor to avoid water short circuiting the motor.

And there are centrifugal pumps out there that can be submerged in water.

A self priming Centrifugal water pump can be used to pump water from a depth instead of using a Submersible water pump.