What is a Submersible pump? Principle, Types, Advantages Disadvantages

Submersible water pumps are a type of centrifugal pump that work immersed in a fluid and serve to pump the water from wells. With a submersible pump, water is pushed up toward the surface rather than pulling it upside. They are specially designed and always submerged in water to be pumped.  

submersible pump icon

The entire assembly comprising the motor and pump is completely submerged in liquid to be processed. A submersible pump unit is a hermetically sealed body, with a pump closely coupled to it.  Generally, it complies with EU and ISO directives.

Submersible Pump Working Principle

The submersible pump is usually introduced into the liquid to push it from one place to another. It is shown in the below figure.

Submersible Pump Working Principle

The submersible pump motor converts kinetic energy into centrifugal energy. Finally, pressure energy lifts the water out of the well.

various types of submersible pumps

Submersible pump specifications

The following are the specifications of submersible pumps that must be considered.

Maximum power (Watts): Depending on this parameter, submersible pumps will move more or less of a fluid.

Maximum pressure height (meter): It is the maximum height up to which the fluid can be pumped.

Maximum discharge flow (liters/hr.): Capacity of the pump to move a certain volume per unit of time.

Maximum immersion depth: Being submerged in a fluid, they must have a range of pressures that they can withstand. This data indicates the depth to which the pump can be subjected.

Pressure Switch: Control panel of the unit that indicates the different operating pressures.

Maximum Size of the solids (mm): Factor that will indicate the maximum size of the residues of the fluids to be pumped.

Automatic stop system: The pumps usually work continuously, without having to turn them on or off. The automatic stop system stops the pump’s motor when there is no fluid to transport and prevents the motor from overheating with possible damage.  

Type of Power: Power can be single-phase or tri-phasic.

Maximum fluid temperature (°C): Working with high-temperature fluids can cause the motor to overheat, causing machine breakdown.

A pump is used to raise liquid using an electric motor to which a submersible pump is connected. It is also used to drain a basin, a tank, a pit, a well, or a flooded basement. It is called a submersible pump because it can be put up submerged underwater.

A submersible pump is capable of draining different types of water: clean water, clear rainwater, wastewater, dirty water, heavy construction site water, and water from sewers.

Please note that not all submersible pumps are suitable for lifting all water. A submersible pump can also be used to distribute water in aquariums, ponds, or other fountains. A low-power pump is sufficient in this case.

How does a submersible pump work?

A submersible pump can be manually turned ON or equipped with a float as shown in the below figure. The float allows it to operate automatically as with the rise and fall of water to be pumped. Some models start and stop immediately, while others need to idle somewhat before stopping.

How does a submersible pump work?

The pumps operate using an electrical power supply: they can be directly connected to the mains in the case of low-power devices or coupled to an electric motor. This device is equipped with a non-return valve which guarantees the movement of water in one direction, preventing it from going back down.

Care should be taken to thoroughly clean the submersible pump after use to reduce the spread of dirt or grease inside the system.

Different types of submersible pumps

The main types of submersible pumps are follows.

  • Deep well pump
  • Bottom suction pump
  • Stainless steel pump
  • Oil filled pump
  • Submersible utility pump
  • Water cooler pump
  • Mixed and axial flow pump

We can further classify the pumps as-

  • Submersible pumps are intended for the discharge of clean water. They are called low-voltage pumps and have short operating autonomy.
  • Lift pumps for dirty water or clear water, resulting from the flooding of a basement, a garage, a cellar, or present in a basin. They are called vacuum pumps.
  • Submersible pumps are used to suck in and then push back clear water, fresh water, and deep water.
  • Submersible pumps are specific to aquariums, and water coolers.
  • Single-stage submersible pumps are mostly used in domestic sewage pumping, drains, and aquariums. Multi-stage are used for underground wells, and oil fields

What about other types of electrical models?

Even if they have a common function which is to be able to operate under a liquid, submersible pumps are distinguished by their device.

The motor of a submersible pump does not soak in the liquid to be drained, whereas the whole of the equipment of a submersible pump is submerged motor included.

Useful for watering green spaces, parks, and gardens, as well as emptying ponds or fountains.

This equipment is suitable when the water levels to be drained are below a height of 8 meters. Beyond this limit, a submersible pump must be used.

Main Parts of Submersible Pump

The following are the main parts of a submersible pump.

  • Clamps
  • Impeller
  • Relief valves
  • Drain valves
  • Check valve
  • Inlet and outlet valve
  • Submersible pump
  • Pressure switch
  • Sediment filter
  • Torque arrester
  • Pump cable
  • Safety rope
  • Tank tees

Advantages of submersible pump

  • The main advantage of a submersible pump is that it never needs to be primed since it is already submerged in fluid.
  • Submersible pumping is a cost-effective method to lift large volumes with less energy consumption.
  • No cavitation threat. A centrifugal pump is prone to cavitation because of low pressure in the suction head. However, the submersible pump pushes water instead of pulling water, thus the probability of developing negative head gets almost eliminated.
  • They are efficient they don’t consume too much energy lifting from deep wells. (Oil exploration).
  • Some submersible pumps can easily handle solids while others are better for liquids only.
  • Their operation is silent, no noise is heard.

Disadvantages of Submersible Pump

  • Over a period, the seals of the pump can become corroded. When this happens, water seeps into the engine making it a useless unit that requires repair.
  • If the submersible pump is not submerged properly inside the water, the pump may get damaged. The dry running of pump may cause overheating of the pump.
  • The submersible water pump is completely hermetically sealed, as a result pump may get rusted over time.
  • These pumps are not one-size-fits-all.
  • Single-stage pumps are used mostly in home and light industrial pumping. This involves pumping sewage, or sumps for drains.
  • The multi-stage ones are used for underground tasks such as oil or water well.

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