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Volute Pumps vs. Diffuser Pumps: What’s the Difference?

By PumpWorks / January 17, 2025
Volute Pumps vs. Diffuser Pumps

When it comes to choosing a pump for your system, it’s important to understand the differences between the two main types: volute and diffuser pumps. We’ve been in the industry for years, we’ve seen these pumps in action, and each has its place.

Volute Pumps

What is a Volute Pump?

A volute pump is a type of centrifugal pump. It’s one of the most common pump designs used in industries like water treatment, manufacturing, and HVAC systems. The volute refers to the spiral-shaped casing that surrounds the impeller. This casing is what sets the volute pump apart, directing the fluid flow and allowing the pump to function efficiently.

How Do Volute Pumps Work?

In a volute pump, the impeller is the heart of the system. When the pump operates, the impeller spins, drawing fluid into the center. As the fluid moves through the impeller blades, it gains speed and is then forced into the spiral-shaped volute casing. This casing gradually expands, allowing the fluid to slow down, which causes the pressure to increase.

Pros of Volute Pumps:

  • Easy to maintain
  • Less complex
  • Reliable for general applications

Diffuser Pumps

What is a Diffuser Pump?

Diffuser pumps are similar to volute pumps in that they are also centrifugal pumps, but they differ in how they handle fluid flow. Instead of a single spiral casing, diffuser pumps use a series of stationary vanes or diffusers placed around the impeller. These diffusers help slow down the fluid as it moves through the pump, allowing for better control over pressure and flow rate.

How Do Diffuser Pumps Work?

When a diffuser pump operates, the impeller spins and draws the fluid in, much like the volute pump. However, as the fluid moves through the pump, it passes through the stationary vanes. These vanes help guide the fluid in a controlled path, slowing it down while increasing the pressure. This makes diffuser pumps (especially useful in applications that require high-pressure performance or where more precise control of fluid flow is needed.)

Pros of Diffuser Pumps:

  • Better at handling higher flow rates
  • More efficient at high pressures
  • Ideal for more demanding applications

A Closer Look at the Differences

Design and Construction

Volute Pumps

A volute pump has a spiral-shaped casing around the impeller. This spiral gradually widens to slow the fluid down and increase its pressure. The design is simple, which makes the pump easy to maintain and cost-effective.

Diffuser Pumps

Diffuser pumps use multiple stationary vanes (diffusers) around the impeller. These vanes slow the fluid and control its flow more precisely. This design helps increase pressure more efficiently (especially in high-flow or high-pressure situations.)

Performance/Efficiency

Volute Pumps

These pumps are great for moderate pressures and lower flow rates. Reliable, and easy to maintain, making them ideal for everyday industrial use  like water treatment or HVAC systems.

Diffuser Pumps

Diffuser pumps are designed for higher pressures and larger volumes. (more efficient in handling high-flow, high-pressure situations)

Maintenance/Cost

Volute Pumps

Because of their simple design, volute pumps are easy to maintain and repair. They’re also more affordable, with fewer parts that require attention.

Diffuser Pumps

Diffuser pumps are more complex and tend to be more expensive to manufacture and maintain. However, their ability to handle high pressure makes them worth the investment in demanding applications.

FeatureVOLUTE PUMPDIFFUSER PUMP
DesignSpiral-shaped volute casingMultiple stationary vanes (diffusers)
Fluid FlowSimple spiral flowControlled flow with diffusers
EfficiencyGood for moderate pressures and flowsBest for high pressures and large flow rates
MaintenanceEasier to maintain, fewer componentsMore complex, requires more attention
ApplicationsGeneral industrial use, water treatment, HVACHigh-pressure, high-flow, heavy-duty industries
CostMore affordableMore expensive

Which One is Right for You?

The choice between a volute and a diffuser pump depends largely on your needs. If you’re dealing with smaller systems or lower flow requirements, a volute pump might be the way to go. But, if you’re dealing with high-flow, high-pressure environments, a diffuser pump could be the better fit.

Contact PumpWorks Today

If you need more help deciding, don’t hesitate to reach out. With years of experience, the experts at PumpWorks are always happy to lend a hand and provide insights.

Contact our team here.

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