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Flexible Impeller Pump Overview

A flexible impeller pump is a positive displacement pump, including a rubber vane and impeller. These pumps are usually present in pumping houses where large amounts of liquids must be filled or transferred.

The flexible impeller pumps are best known for their versatility as they can handle thin and viscous liquids.


These pumps can also handle solids in suspension up to 25mm on average. The flexible impeller pump offers multiple benefits. Let us first understand how these pumps work.

Flexible Impeller Pump Brands

Jabsco Logo

Ideal Jabsco Applications:

  • Waste
  • Dewatering
  • Portable Utility
  • Mixing
Oberdorfer Logo

Ideal Oberdorfer Applications:

  • Irrigation
  • Industrial heat transfer
  • Waste
  • Dewatering
  • Portable utility
  • Filtration
  • Mixing
  • Fire Fighting

How do Flexible Impeller Pumps Work?

The impeller starts storing liquid through the inlet and moving the fluid through positive displacement when turned on. The vanes begin to change their motion once the liquid reaches the discharge port.

The impeller deforms while moving inside the pump, allowing the liquid to pass from the inlet to the outlet at a steady, spike-free, and pulse-free rate.

The space between each vane creates an individual chamber for the liquid to pass and acts as several valves in the machine.

The flexible impeller pump’s simple mechanism and self-priming abilities make it ideal for dosing, filtration, transfer, and many other tasks.

Benefits of Flexible Impeller Pumps

Following are the top benefits of using a flexible impeller pump for liquid pumping and transferring needs.

Fluid Variety

The impellers in the flexible impeller pumps consist of different materials, including rubber, nitrile, and silicon. Each of these materials has its benefits, such as liquid and chemical resistance, making them ideal for industrial and commercial applications.

The rubber bends allow more viscous liquid to flow through the pump. The vanes of the flexible impeller pump also bend, preventing machine damage.

Self Priming Abilities

The flexible impeller pumps can prime themselves up to 6m dry, making them ideal for long-term use. These pumps maintain a tight seal with the walls of the pump, making the pumps ideal for tasks requiring good suction lift capacity.

The tightly sealed mechanism makes the flexible impeller pumps ideal for tasks like removing fluid from sumps and stripping IBCs without priming during the installation.

Low Pulsating Flow

The flexible impeller pumps create a smooth flow because of their unique design and adaptable components. The output flow is softer, without any pressure spikes, and has consistent transferring capabilities.

The smooth flow makes flexible impeller pumps ideal for long liquid transfers. These impeller pumps are also great for tank-to-tank transfer as they rarely have any suction issues.

Reversible Operations

Impeller pumps can make the liquid move in both directions, meaning that the pump controls the direction the fluid flows in. Dual-direction flow allows the pump to return any access liquid once a container is full, drying the pipelines or tanks.

Low Shear Operations

The flexible impeller pumps provide consistent operating options as the pumps can transfer liquids even with low motor speed. The low motor power operating saves the fluids from any shear damage or compromise of their structure. Some common examples of such liquids include the following:

  • Glue
  • Olives
  • Creams

Bottom Line

The flexible impeller pumps include rubber or silicon vanes allowing consistent, spike-free liquid transfer between containers. These pumps are ideal for handling viscous and thin liquids and soft solids. 

The tech guys at Jabsco and Rule thought “How cool would it be to show what’s going on inside an impeller pump!” Well, with the help of our machinist who made us a clear end-cover and the addition of some dish-washing liquid, we were able to show you how the vanes fold over and push the liquid out of the pump head. 

Ready to Tackle Your Next Pump Installation or Maintenance Project?