REDUNDANT SEAL APPARATUS AND METHOD

摘要

An apparatus includes a rotatable shaft having a shaft surface and a first seal disposed in a sealing engagement with the shaft surface. At least a second seal is disposed in a first position relative to the rotatable shaft where the second seal is not in sealing engagement with the shaft surface and is movable to a second position relative to the rotatable shaft where the second seal is in sealing engagement with the shaft surface.