Centrifugal pumps are one of the most popular and frequently used pumps in the world. They can be found in numerous industrial applications. Depending on the application, the right centrifugal pump has to be chosen. If you're in the market shopping for centrifugal pumps, you would have come across the term "multistage centrifugal pumps." Wondering if it's the right choice for your needs? Allow us to help.
Single-stage Centrifugal Pump vs Multistage Centrifugal Pump: What's the Difference?
As the names imply, the key difference between the two is the number of impellers (also known as stages). Single-stage centrifugal pumps have only one impeller. On the other hand, multistage pumps have two or more impellers.
The impeller plays a crucial role in the operation of a centrifugal pump. It pressurizes and transfers the fluid/liquid. Since multistage pumps have more than one impeller, the flow rate and pressure ranges in a multistage are more efficient than single-stage pumps.
Inside a multistage pump, each impeller acts like a stand-alone single-stage centrifugal pump. Hence, it works like a chain of single-stage pumps connected linearly. As the liquid moves from one stage to the next, the pressure rises while the flow remains constant.
As a result, multistage centrifugal pumps generate higher power and higher pressure with small motors, thereby using less energy.
Where are multistage centrifugal pumps used?
Multistage centrifugal pumps are used in various industrial applications due to their ability to transfer fluids at higher pressures. Here are some industries that use multistage centrifugal pumps:
Fire fighting – Generates high-pressure water used in extinguishing fires.
Boiler feedwater – To pump feedwater into a steam boiler.
High-pressure cleaning – Generates a high-pressure stream of water to clean dirt and dust off objects like cars, windows, etc.
Reverse Osmosis – Used for desalination.
Irrigation – Multistage pumps are used to pump water via an irrigation system.
Water circulation – Multistage pumps add pressure to the system, helping in the continuous circulation of water.
Snowmaking – Used in pressurizing water for artificial snow generation.
Different Types of Multistage Centrifugal PumpsMultistage centrifugal pumps can be classified into two types:
Horizontal centrifugal pumps
Vertical centrifugal pumps
What are horizontal multistage centrifugal pumps?
Horizontal multistage pumps are the most commonly used pumps and are used in several of the applications mentioned above. In this pump, the liquid travels horizontally through several impellers. Horizontal pumps can handle higher flow rates than vertical pumps (the one exception to this rule is vertical turbine pumps that can handle higher flow rates). It's easy to identify horizontal multistage pumps via their segmented casing.
Despite all the benefits, horizontal multistage pumps have certain drawbacks. They are:
Need skilled pump operators
It can be more expensive compared to vertical multistage pumps
What are vertical multistage centrifugal pumps?
Vertical pumps are not extensively used like horizontal pumps. Their applications are limited. As the name implies, these pumps are vertically oriented, with the impellers are placed on top of each other. The clearances in vertical pumps are smaller than their horizontal counterparts. This makes them ideal for clean-water applications.
These pumps are ideal for applications that don't have ample floor space. They can deliver higher pressures with just one motor and a single pump body. Vertical multistage pumps have certain limitations like:
They cannot handle solids or debris
More likely to deadhead
Deadheading is when the water inside the pump churns continuously, thereby converting the water into vapour. Deadheading causes irreversible damage to centrifugal pumps.