Submersible pump impellers make or break the pump

The impeller on a submersible pump makes a big difference in preventing blockages. Whether it’s for storm water or sewage, for high peak flows or just occasional use, choosing the right option will have long-lasting benefits. Every type balances the need for efficiency and the need to handle varying solids sizes and quantities. Each manufacturer has their own range of precisely designed versions, and the four main choices of submersible pump impeller are described below.

Vortex impeller

A ‘vortex’, or whirlpool, is created in the impeller bowl by the recessed vortex impeller. This whirlpool sucks the water into the bowl and pushes it out through the discharge. As the water doesn’t pass through the impeller, solids up to the size of the discharge of the pump can pass through. It is an inefficient pumping method, which isn’t suitable for high head applications.

Single channel impeller

Liquid actually passes through a single channel impeller. This means that it is more likely to get clogged by long, fibrous material in the water, although solids can still be handled. The advantage over the vortex impeller is a much higher efficiency.

Screw impeller

Normally used for pumping liquids with higher viscosity, such as sludge or slurry. They have a ‘screw’ instead of a standard impeller with vanes. It uses the viscosity of the liquid to carry it through the pump and out of the discharge, with good efficiency and no vanes to clog the pump.

Macerator

Actually a two-stage impeller, the macerator impeller first chops any solids into smaller, manageable pieces, then pumps it using an efficient multi-channel impeller. This would be prone to blockages if the solids weren’t already dealt with.