PSG

# Centrifugal Pump Basics: Types Of Impellers And Specific Speed

By: PSG

In the latest edition of the Centrifugal Pump Minute, we discuss the different types of impellers as well as specific speed and how it is calculated.

As we go forward, you have obviously a variety of different impeller designs; closed impellers, semi-open, and open impellers. The hydraulic performance of these impellers is going to be defined by how the impellers are designed.

There’s a value that’s called specific speed that people within the pump world are going to talk about. The specific speed it’s a dimensionless theoretical quantity that characterizes the pump’s performance and head flow speed. You always calculate this within or at the pump’s best efficiency point. What’s on the slide here are the equations that are used to calculate specific speed. I’m not going to go into that in detail, but I do want to show you the chart that’s shown towards the bottom of the screen.

To give you kind of a different look at this, there are a few different impellers, the design of these impellers, and where they would land on a specific speed chart. On the far left here, you have what would be a traditional ASME b73.1 low flow impeller, and this impeller is a complete radial design impeller. It’s going to generate very high head pressures very low flow rate. You can tell that by the impeller design. Then as you start moving towards the left, you can see that the vein the profile starts getting wider or taller, and the flow begins to be less radial in nature, more axial in nature, and the specific speed begins to increase.

Watch another Centrifugal Pump Minute video.

# Centrifugal Pump Basics: Types Of Impellers

In this edition of the Centrifugal Pump Minute, James Farley, Senior Director of Product Management for Griswold, takes a look…

# Centrifugal Pump Basics: History

Do you know the history of centrifugal pumps? In this Centrifugal Pump Minute, we provide a brief overview of centrifugal…

# Centrifugal Pump Basics: How It Works

In this edition of the Centrifugal Pump Minute, James Farley, Senior Director of Product Management for Griswold, goes through how…

## Related Whitepapers

### Blackmer® MAGNES Series Sliding Vane Pumps Solve Legacy Pain Points

Introduction There are some things you just can’t avoid: death, taxes, and a pump’s common operational pain points- leaks, dry run, solids handling, cavitation-causing NPSH…

### Buffer & Barrier Fluids

Author: Mark Savage, FSA Member As operators of pumping equipment become more focused on the safety, reliability and environmental impact resulting from shaft seal leakage,…

### Where mechanical seals meet pumps: What is the next generation?

Almost all centrifugal and rotary pumps require a sealing system to provide sealing integrity of the drive shafts carrying the impellers and protect against pumped…

### Using Power Sensing To Monitor and Protect Pumps

Pumps play an increasingly important role in today’s manufacturing. The global market for pumps is over \$60B, and is expected to continue growing 6% into…