Maintenance and Emergency Run Secondary Seal

A maintenance and emergency run secondary seal mountable to a rotatable shaft is described. The seal includes a housing; a sealing ring having a double-tapered receiving channel located between two exterior surfaces and an interior wear surface; a lantern ring having a double-tapered profile for enabling engagement within the receiving channel of the sealing ring to form an air chamber between the sealing ring and the lantern ring; and an arrangement for directing and controlling pressurized air to the air chamber. The operating positions for the sealing ring are: where the sealing ring is spaced from the shaft, where a portion of the interior wear surface of the sealing ring is closed-in on the shaft to enable an emergency run secondary seal to permit shaft rotation and where the sealing ring is in full contact with the shaft to enable a static seal.