Patent ID: 8272643

Claim:
An air-tiding 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 extending to an end which is adjacent to an outermost circumferential surface along said seal runner and is separated from said outermost circumferential surface by a gap; (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 or at least one hydrodynamic pocket disposed along said surface in an outward radial arrangement with respect to said circumferential dam, said outermost circumferential surface along said seal runner has a notch that varies said gap depending on relative position between said circumferential dam and said sealing surface, a maximum distance between said circumferential dam and said sealing surface results in a minimum clearance of said gap, a minimum distance between said circumferential dam and said sealing surface results in a maximum clearance of said gap.