What is a Multistage Pump? | Multistage Pump VS Single Stage Pump

What is a Multistage Pump?

A multistage pump is a type of centrifugal pump that pressurizes the fluid in multiple stages (two or more stages). Because this pump uses more than one stage, therefore, it is known as a multistage pump. Each stage has guide vanes, a diffuser, and an impeller, and these components are enclosed in the pump casing. A multistage pump uses an impeller to increase the pressure of the water instead of a piston. The types of impellers for each stage may be different or identical.

A multi-stage pump is a type of pump that has a pull rod.  In the case of these pumps, the water pressure on the outlet of the pump is very high than the inlet water pressure. These types of pumps rely on the impeller revolution to obtain centrifugal force.

This centrifugal pump uses multiple chambers. When the water enters into the chamber of 1st stage, the impeller increases its speed, and the diffuser further converts this speed of water into pressure. After passing through the 1st stage, the pressurized water sends to the 2nd stage. In this way, this process continues until the water reaches its desired pressure and pumps to the desired area. The suction, compression, and discharge process of the multistage pump is based on changes in the volume of the pump chamber. Therefore, it is a centrifugal pump that has a changeable volume.

multistage pump

These pumps mostly use for applications that require high pressure to transport liquids. Because such high pressure can only achieve by using a multistage centrifugal pump, generally, the liquid goes through several stages; due to that, its pressure increases, and it can efficiently pump over longer distances. Therefore, pressure-raising systems generally use multistage pumps that require constant flow and pressure. A ring-section pump is an example of multistage pumps that use for irrigation systems and boiler feed systems.  

Read Also: Different Types of Pumps

Working of Multistage Pump

As we discussed earlier that a multistage pump has multiple stages. It works in more than one stages. A multistage pump works in the following way:

  • First of all, the fluid introduces from the outside into the impeller eye of the 1st stage.
  • As the fluid strikes the impeller vanes, the vanes provide kinetic energy and increase fluid speed.
  • A centrifugal force inside the impeller moves the fluid axially and radially 
  • Due to the centrifugal force, this fluid discharge from the impeller blades and enters into the diffuser.
  • The diffuser increases the fluid pressure by reducing its speed and sending it into the 2nd stage.
  • This process continues until fluid passes from all the stages of the pump, and then it discharges and pumps to the desired area. 

For a better understanding, watch the following video:

Multistage Pump Types

The multistage pumps have two major types:

  1. Horizontal multistage centrifugal pumps
  2. Vertical multistage centrifugal pumps

1) Horizontal Multistage Centrifugal Pumps

This multistage centrifugal pump has a segmented pump housing with modular intermediate parts. The spinning parts are fixed between the bearing housings, which improves the balance of the parts under high pressure.

In general, this pump can handle higher flow rates compared to a vertical multistage pump (except for a vertical turbo pump). It shows excellent productivity and high-quality material.

multistage horizontal pump

Applications of Horizontal Multistage Pump

The horizontal multistage centrifugal pump uses for the following applications:

  • Mine dewatering
  • Condensate
  • Snowmaking
  • High-Pressure Cleaning
  • Pressure Boosting
  • Cogeneration
  • Reverse Osmosis
  • Spray
  • Boiler Feed
  • Shower
  • Pressure Boosting
  • Boiler feed systems
  • Condensate

2) Vertical Multistage Centrifugal Pump

A vertical multistage pump is a famous centrifugal pump that has more than one runner. These runners are mounted on the same shaft if a single shaft drives the pump. The runner gets mechanical power from an external source, such as an electric motor through a shaft.  This runner moves according to the movement of the shaft.

vertical pump, multistage pump

This type of pump uses a centrifugal force to transfer the fluid from the impeller to the diffuser. A diffuser uses to increase the pressure of the fluid by reducing its speed. Vertical multistage pumps can easily install in the low space location. However, they need small space for their installation due to their vertical design.

Applications of Vertical Multistage Pumps

Vertical pumps install for high-pressure applications.  Some major applications of these pumps are given below:

  • Agricultural
  • Irrigation
  • Municipal water supply
  • High rise building
  • Industrial
  • Medical
  • Commercial
  • Desuperheater feed
  • Boiler feedwater
  • High-pressure shower system

Applications of Multistage Pump

A multistage pump uses for different applications all over the world. The common applications of the multistage pumps are given below:

  • Water circulation
  • Cooling/heating conditioning
  • Fire fighting
  • Irrigation
  • Boiler feed
  • Water supply boosting
  • Reverse osmosis
  • Desuperheater feed
  • Boiler feedwater
  • Medical
  • Commercial

What is a Single Stage Pump?

A single-stage pump pressurizes the fluid in only a single stage. For example, this pump has only one stage. Therefore, it uses only one impeller and diffuser for pressurizing the fluids. The impeller of the pump is connected with a shaft driven by an engine or electric motor. It can lift water up to 125 meters.

single stage pump

This pump has the simplest design and available in multiple designs.  There are many design changes to meet the load requirements of the application. The design of the single stage pump impeller has been modified to accommodate solid-filled, unclean, and clean fluids with a variety of mechanical seal types to accommodate it according to the application requirements.

Advantages of Single stage Pump

  • A single stage pump has a simple structure
  • It has stable performance
  • This pump has high speed
  • Small volume
  • It has lightweight than a multistage pump
  • It has high efficiency
  • Large flow
  • These pumps have an easy operation and repairing
  • Single-stage centrifugal pumps are available in horizontal, vertical, single-suction, double-suction designs.
  • It has easy maintenance.
  • Long service life
  • Highly reliable

Disadvantages of Single Stage Pump

  • It has low efficiency
  • It has only one stage for the fluid. Therefore, it can only pump fluids for a short distance.

Applications of Single Stage Pump

  • These pumps use for sewage technology
  • These use for industrial cleaning applications
  • This centrifugal pump uses for energy technology
  • It uses for cooling applications

Single Stage Pump VS Multistage Pump

Single Stage PumpMultistage Pump
The single stage pump can pump fluid up to 125mA multistage pump can pump fluid more than 125m.
It has a low-pressure headIt has a high-pressure head
This pump has an only single stageIt has more than one stages
It works with only a single impellerThis pump has multiple impellers
It provides low pressurize fluidThis pump provides high pressurize fluid
Single stage pump has less efficiencyIt is more efficient than single stage pump

See Also:

1) How does a Centrifugal Pump Work?

2) How does a Reciprocating Pump work?

Leave a Comment