Abstract: A seal for preventing leakage around a rotary shaft extending through a structural casing comprising an annular stationary rigid seal secured to the structural casing for surrounding the rotary shaft. The stationary rigid seal has a smooth sealing surface for establishing a seal, and a resilient rotary seal adapted to be secured to the rotary shaft and having an annular projecting edge for contacting the smooth sealing surface under a biased pressure to form a seal in conjunction therewith. The projecting edge is formed by the convergence of inner and outer forward surfaces. A radial surface extends to the inner concentric forward surface from a torque point at its forward cylindrical base. An outer rearward surface extends to the outer concentric forward surface from a pivot point at its rearward cylindrical base. The outer forward surface forms an angle with the central axis of the seal in a plane through the central axis of the seal of from 40.degree. to 60.degree..

Abstract: A dry-face sealing method for preventing leakage around a rotary shaft uses an annular rigid seal having a smooth sealing surface and an annular resilient seal having a projecting sealing edge aligned coaxially therewith. The annular resilient seal has a breaking elongation of at least about 100 percent of its original length, the resilient seal being stretched at least about 20 percent and less than 40 percent of its breaking elongation in a direction substantially parallel to the smooth sealing surface to align polymeric resilient seal components in a direction parallel with the smooth sealing surface and smooth the sealing surface thereof. The projecting edge, because of its shape and position, functions as a stress concentrator, concentrating the stress hardening effect on the sealing surface of the projecting edge.