Patent ID: 8434766

Claim:
A seal for preventing axial leakage through a radial gap between a stationary structure and a rotating structure, wherein the radial gap is defined by an inner radial surface that opposes an outer radial surface across the radial gap, the seal comprising: at least one land disposed on one of the inner radial surface and the outer radial surface, the at least one land comprising an upstream surface that is configured to slope upstream at an angle from about 10 degrees to about 40 degrees with respect to a radial axis; at least one first tooth that projects from the other of the inner radial surface and the outer radial surface; at least one second tooth that projects from the other of the inner radial surface and the outer radial surface, the at least one second tooth configured to be shorter than the at least one first tooth; wherein at least one of the first tooth and second tooth, is configured to extend at a first angle upstream, the first angle defined between a radial surface from which the first tooth or second tooth projects and an upstream surface of at least one of the first and second tooth, and wherein the first angle is less than or equal to about 80 degrees.