US Patent 7891670 Multi-directional shaft seal

A dynamic seal provides for the return of captured lubricant to the lubricant side regardless of the direction of rotation between the seal and the shaft. The seal uses bi-directional pumping elements to facilitate the hydrodynamic pumping of the captured lubricant in response to relative rotation. The seal includes a valve portion that can change a pumping rate of particular pumping elements such that more lubricant is pumped toward the lubricant side than the non-lubricant side.