Types of Pump Casing in Centrifugal Pumps
Centrifugal pumps are widely used across industries because of their simple design, high efficiency, and ability to handle various fluids. One of the most important components that determines pump performance is the casing. The casing guides the fluid, maintains pressure, reduces losses, and protects the internal parts of the pump. Understanding the types of casing in centrifugal pump design helps you choose the right pump for your application.
In this blog, we will explain the pump casing types, how each design works, and when they are used — in a clear, user-friendly, and SEO-optimized way.
What Is Pump Casing?
The pump casing is the outer shell that houses the impeller. Its main roles include:
- Collecting and directing the fluid from the impeller
- Converting velocity energy into pressure (head)
- Supporting and protecting the pump’s mechanical components
- Ensuring smooth and efficient flow without turbulence
Different processes require different casing designs, which is why centrifugal pumps use volute casing, vortex casing, and diffuser casing.
1. Volute Casing
Volute casing is the most widely used casing of centrifugal pump. It features a spiral-shaped chamber that gradually increases in area from the tongue region to the discharge.
How It Works
As water leaves the impeller, the volute shape collects the high-velocity fluid. The gradually expanding area reduces velocity and converts it into pressure before discharge.
Advantages
- Simple and efficient design
- Good pressure conversion
- Handles different flow rates
- Suitable for a wide range of applications
Applications
- Water supply
- Industrial pumps
- HVAC systems
- Chemical and process industries
Volute casing is the standard option when looking for reliable pressure generation from a centrifugal pump.
2. Vortex Casing
The vortex casing in centrifugal pump design includes a circular chamber around the impeller, creating a vortex motion in the fluid.
How It Works
The vortex effect helps increase pressure by reducing friction losses. The swirling motion improves flow stability inside the casing.
Advantages
- Higher efficiency compared to simple volute
- Reduced shock losses
- Better for handling suspended particles
- Lower chances of clogging
Applications
- Sewage pumps
- Slurry pumps
- Wastewater management
- Applications requiring smooth passage of solids
If your process involves fluids with particles, vortex casing provides better performance and longer service life.
3. Diffuser Casing
Diffuser casing uses a set of fixed guide vanes around the impeller to convert velocity energy into pressure more efficiently.
How It Works
The fluid leaves the impeller at high speed and passes through the diffuser vanes. These vanes slow the flow, increasing pressure with minimal loss.
Advantages
- High efficiency
- Stable performance
- Best for high-pressure applications
- Reduces vibration and noise
Applications
- Multi-stage pumps
- Boiler feed pumps
- Oil & gas installations
- High-pressure industrial systems
Diffuser casings are ideal when consistent pressure and energy efficiency are priority requirements.
Volute Casing vs. Vortex Casing: What’s the Difference?
Both designs are commonly discussed together as volute and vortex casing. Here’s a simple comparison:
| Feature | Volute Casing | Vortex Casing |
|---|---|---|
| Design | Spiral-shaped | Circular chamber with vortex zone |
| Efficiency | Good | Very good |
| Solids handling | Moderate | Excellent |
| Pressure conversion | Effective | Smooth with fewer losses |
| Best for | Clean liquids, general industry | Wastewater, slurry, solids-loaded fluids |
How to Choose the Right Pump Casing Type
When selecting the types of casing in pump design, consider:
- Nature of the fluid (clean, dirty, slurry, chemical)
- Required pressure and flow rate
- Pump size and installation space
- Operating efficiency
- Maintenance requirements
Each casing type serves a specific purpose — choosing correctly ensures long-term performance and energy savings.
Conclusion
The types of casing in centrifugal pumps — volute, vortex, and diffuser — each play a unique role in improving pump performance and efficiency. Understanding these pump casing types helps industries select the right centrifugal pump for water supply, chemical processing, wastewater, or high-pressure applications.
Choosing the correct casing in centrifugal pump ensures smoother operation, reduced losses, and better overall reliability.
If you need assistance in selecting the right pump for your application, MKFlow provides expert-engineered solutions for all industrial pumping needs.
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