Patent ID: 8657297

Claim:
An air-riding seal system comprising: (a) a primary seal assembly movable between a seal runner extending from a rotatable shaft and a housing structure, said primary seal assembly including: (i) an annular seal ring having a cross section that is substantially L-shaped and a surface with a step face and a circumferential dam, said surface disposed opposite of a sealing surface along said seal runner; and (ii) an arcuate support arm attached at one end to said annular seal ring and having a tooth at another end adjacent to an outermost circumferential surface along said seal runner, said tooth and said outermost circumferential surface separated by a radial gap, a cavity or a depression machined into or formed onto said seal runner so that said cavity or said depression is disposed along and bounded by said outermost circumferential surface, said tooth adjacent to and movable over said cavity or said depression, a maximum axial distance between said circumferential dam and said sealing surface minimizes said radial gap, a minimum axial distance between said circumferential dam and said sealing surface opens said radial gap, said radial gap at said maximum axial distance smaller than said radial gap at said minimum axial distance; (b) a secondary seal ring disposed between and contacting said primary seal assembly and said housing structure so as to form a bore seal and a face seal therewith; and (c) a structure along said surface which increases stiffness of a thin film between said surface and said sealing surface, said structure having a plurality of radial dams disposed along said surface in an outward radial arrangement with respect to said circumferential dam.