Single-Stage Pump vs Multi-Stage Pump

What are the Different Stages of Submersible Pumps?

A submersible pump is a sealed pump device that operates by pushing liquid, rather than pulling it, during the pumping process. As the name suggests, the pump is fully submerged in the liquid being pumped, which enables it to function in this manner. To prevent pump cavitation, which can damage moving parts by creating vapor bubbles, the pump can be lowered into a shallow hole before use. Submersible pumps are used in a wide range of industrial and commercial applications.

How do the impellers of a submersible pump contribute to its efficient operation?

In a submersible pump, the impeller rotates and transfers mechanical energy from the driving motor to increase the speed of water flow away from the center of rotation. The number of impellers in a submersible pump is known as the “stage”. There are two types of submersible pumps, single-stage pumps, and multistage pumps.

What is a single-stage pump in a submersible pump?

A single-stage pump is a type of submersible pump that is commonly used in industrial, agricultural, and residential water supply and drainage systems. Compared to multistage or two-stage pumps, single-stage pumps are more energy-efficient and easier to manufacture.

The quality of a single-stage:

The quality of a single-stage submersible water pump can be ensured by manufacturing it with a stator, pump body, inlet, and outlet, and using a stabilizer during pump operation. Skilled professionals use punching machines to create a smooth stator for optimal performance. Additionally, high-quality equipment is used to conduct thorough pump testing.

Single Stage Work Principle:

A single-stage submersible pump operates using a single impeller. When in use, water is drawn into the pump body through the inlet and then enters the impeller section. As the impeller rotates at high speed, water is expelled from the pump body along with the impeller. This creates a large vacuum in the inlet, starting the process all over again. In general, the impeller in a single-stage submersible pump is positioned near the pump inlet. The pump’s head and flow are determined by the motor’s power, which must remain submerged throughout the operation.

Single-Stage Applications:

Due to their compact design and shape, single-stage submersible pumps have a wide range of applications, including industrial and mining water supply and irrigation, residential water supply and transportation, as well as city drainage and supply.

What is a Multistage Pump? 

A multistage pump is a type of pump that consists of two or more impellers arranged in series. Each impeller is mounted on a common shaft and separated by a diffuser or a stage casing. When the pump operates, the fluid is gradually pressurized as it passes through each impeller stage, resulting in a higher discharge pressure at the outlet. Multistage pumps are commonly used in high-pressure applications, such as water supply systems, boiler feedwater, and oil and gas production.

Multistage Pressure Capability:

Multistage submersible pumps are a popular choice when a single-stage pump is unable to meet the necessary pressure requirements, due to their effective use of impellers installed and rotated on a single shaft, functioning as independent pumps. This design significantly increases pressure capability compared to single impeller pumps, as the head increases proportionally with the flow from one stage to the next.

Multistage Efficiency:

The use of multiple impellers in a multistage pump allows for smaller impeller diameters and tighter clearances between the impeller and volute, resulting in maximum hydraulic efficiency for each impeller. This efficiency enables multistage pumps to operate with smaller motors and consume less energy, while still providing high performance.

Multistage Application:

Multistage pumps are commonly used in applications where high pressure and low viscosity fluids are involved, as the tight impeller clearance with the pump volute cannot handle solids and abrasive content. Some of the popular applications for multistage water pumps include :

  • Increasing water supply for boilers
  • Reverse osmosis processes 
  • Irrigation
  • Firefighting
  • Heating and cooling systems
  • water flow control.

The difference between a Single-Stage Pump and a Multi-Stage Pump:

The Maximum lift is different:

A submersible pump with a single-stage, single-suction design can only achieve a maximum head of 125 meters. However, a multistage water pump is capable of achieving more than 125 meters of the head. Therefore, when pumping heights exceed 125 meters, multistage pumps should be considered, whereas a single-stage pump is sufficient for heights under 125 meters.

Different Stages of the Pump:

 Single-Stage refers to pumps that have only one stage, and as a result, there has been a trend toward increasing the number of stages in single-stage pumps. 

Different Number of Impellers:

A single-stage pump has only one impeller, while a multistage pump has two or more impellers. Both pumps are capable of handling liquid medium heads greater than 125 meters. However, for heads exceeding 125 meters, a horizontal multistage pump must be used.

Which one is Better?

When it comes to choosing between single-stage and multistage water pumps, the decision ultimately depends on the specific operating conditions and requirements of the site. While multistage pumps are often more cost-effective, the choice should be based on actual needs and operating data.

It’s important to note that the compression stage is a key factor in determining the effectiveness of a pump, and this can vary between single-stage and multistage pumps. In addition to the impeller, other components such as the stator holding ring and inter-stage seal also play a role in the compression stage of the pump.

Wrapping Up!

This blog shares a lot about the different stages of Submersible Pumps

To know more about the different elements stages of Submersible Pumps,

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