Patent ID: 7261300

Claim:
In a gas riding annular face seal for mounting between a first structure and an adjacent second structure so that the annular face seal separates a first region from a second region, at least one of the structures being rotatable relative to the other, the improvement comprising: the face seal comprises a flexible annular top plate for mounting on such first structure; the top plate having an undulate face surface, at least when such structures are rotating relative to each other, for generating a riding gas film between the top plate and such second structure, the top plate (a) being sufficiently flexible to be compliant to out-of-flat distortions between the first and second relatively rotating structures, and (b) having a plurality of sector plates on the face surface; a support spring system for rendering the top plate compliant to out-of-flat distortions and axial excursions between the rotating structures while maintaining the riding gas film; and a seal ring positioned between the top plate and the structure on which the face seal is mounted to establish a barrier to gas flow across the face seal, whereby the face seal is able to maintain a pressure differential between the first and second regions.