The pumps are most commonly used to pump non-compressible fluids. This article explains the multistage pump working, its types, its application, and the difference between the single-stage pump and multistage 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.
It contains two or more chambers. Each compression stage contains guide vanes, a diffuser, and an impeller. 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 design of the impeller varies for each stage.
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 type of centrifugal pump uses multiple chambers for pressurizing the working fluid. When the water enters 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 is transferred 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 processes of the multistage pump are based on the change in the volume of the pump chamber. It is known as a centrifugal pump because it has changeable volumes.
Multistage pumps are most commonly used for applications that require high pressure to pump liquids. Such high pressure can only be achieved by using a multistage centrifugal pump. In this pump, the liquid goes through several stages; due to that, its pressure increases, and it can efficiently pump over longer distances.
Therefore, systems that require constant flow and pressure generally use multistage pumps. A ring-section pump is an example of a multistage pump 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 stage. A multistage pump works in the following way:
- Firstly, the fluid enters from the outside into the impeller eye of the 1st stage.
- As the fluid strikes the impeller blades, the blades provide kinetic energy and increase fluid speed.
- A centrifugal force moves the fluid axially and radially inside the impeller.
- Due to the centrifugal force, this fluid is discharged from the impeller blades and enters 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 is discharged and pumped to the desired area.
For a better understanding, watch the following video:
Multistage Pump Types
Multistage pumps have the following types:
- Horizontal multistage centrifugal pumps
- Vertical multistage centrifugal pumps
1) Horizontal Multistage Centrifugal Pump
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.
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
Read More: Different types of Centrifugal Pumps
2) Vertical Multistage Centrifugal Pump
A vertical multistage pump is a famous centrifugal pump that has more than one impeller. These impellers are mounted on the same shaft if a single shaft drives the pump.
The impeller gets from an electric motor or engine through a shaft. This impeller rotates according to the movement of the shaft.
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 a small space for their installation due to their vertical design.
Read Also: Working of Booster Pump
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 multistage pumps are most commonly used for:
- 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 one stage. Therefore, it has only one impeller and diffuser for pressurizing the fluids. The impeller of the pump is connected to a shaft driven by an engine or electric motor. It can lift the water up to 125 meters.
This pump has the simplest design and is 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 according to the application requirements.
Advantages and Disadvantages of Single-Stage Pump
The single-stage pumps have the following advantages and disadvantages:
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 easy operation and repair.
- Single-stage centrifugal pumps are available in horizontal, vertical, single-suction, and double-suction designs.
- It has easy maintenance.
- Long service life.
- Highly reliable.
Disadvantages of Single-Stage Pump
- The single-stage pump 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 are used for industrial cleaning applications.
- It uses for cooling applications.
Single Stage Pump VS Multistage Pump
The main difference between the single-stage pump and the multistage pump is given below:
| Single Stage Pump | Multistage Pump |
|---|---|
| The single-stage pump can pump fluid up to 125m. | A multistage pump can pump the fluid of more than 125m. |
| It has a low-pressure head. | It has a high-pressure head. |
| This pump has only a single stage. | It has more than one stage. |
| It works with only a single impeller. | This pump has multiple impellers. |
| It provides low pressurize fluid. | This pump provides high pressurize fluid. |
| The single-stage pump has low weight. | The multistage pumps are heavy pumps. |
| Single-stage pump has less efficiency | It is more efficient than single stage pump |
| It needs a small installation place. | It requires a large installation area. |
FAQ Section
What is a Single Stage Pump?
A centrifugal pump that pressurizes the working fluid in a single stage is known as a single-stage pump
What are the parts of the Single Stage Pump?
The single-stage pump has the following major parts:
- Diffuser
- Compression cylinder
- Impeller
- Shaft
What is the difference between the single-stage pump and multi-stage pump?
The main difference between a single-stage pump and a multi-stage pump is that a single-stage pump completes the pressurization process in a single stage, while a multi-stage pump completes pressurization in more than one stage.