Patent ID: 8622690

Claim:
An inter-propellant thrust seal for a rocket engine comprising: a stationary housing; a rotor shaft rotatably supported within the stationary housing; a forward first seal and a forward second seal forming a forward purge chamber between the stationary housing and the rotor shaft; an aft first seal and an aft second seal forming an aft purge chamber between the stationary housing and the rotor shaft; a purge fluid line extending through the stationary housing to provide a purge fluid to the forward and aft purge chambers through the forward second seal and the aft second seal; an axial thrust piston extending from the rotor shaft and forming a chamber wall of the aft purge chamber; and, a fluid reacting surface area of the aft purge chamber being larger than a fluid reaction surface area of the forward purge chamber such that the purge fluid pressure in the aft purge chamber produces an axial thrust on the rotor shaft.