Pump action stops leaks

Freudenberg DPSM rotary shaft seals from Oswald Seals have a pumping action which causes lubricant, that might otherwise leak and ruin finished products, to be returned to the cavity from which it originated.

The design of the dynamic DPSM seal features a lip that is formed in such a way that the reaction between it and the rotating shaft creates a pumping action. The action works exactly the same regardless of the direction of shaft rotation.