Wilfley invented the dynamic expeller almost a century ago and has continued to lead advancements in hydrodynamic sealing technologies ever since

It has been the foundation for every Wilfley pump design, dating all the way back to the ground-breaking Model A slurry pump in 1919.

How the Dynamic Expeller Works

The Wilfley dynamic expeller provides ZERO leakage during pump operation. At startup, the pump fluid is pulled away from the shaft by the centrifugal forces generated by the expeller. This liquid interface effectively isolates the pump fluid from the shaft. At shutdown, the static seal closes before any pump fluid can escape.

The dynamic expeller, combined with one of Wilfley’s proprietary static seals, provides superior sealing compared to conventional sealing systems like mechanical seals and compression packing.