Abeyance seal for high temperature, high pressure applications

摘要

An abeyance seal includes a polymer actuation ring, which defines a flexible sealing lip normally spaced from the shaft. When subjected to leakage, this element collapses against the shaft and forms an initial sealing. Secondarily, a metal sealing/anti-extrusion ring provides a second seal during leakage. The polymer ring provides the initial sealing function during leakage at low differential pressure, and once the polymer ring seals to the shaft, increased sealed pressure loads the polymer ring against the metal sealing/anti-extrusion ring causing it to deform so that the metal ring comes into contact with the shaft to form a second seal.

主权项

1. An abeyance seal which prevents leakage of sealed fluid to environment along a rotatable shaft and radially opposed housing, said abeyance seal comprising:
a polymer actuation ring, which provides a first seal against a shaft surface during leakage, said actuation ring comprising a flexible sealing lip and projecting radially inwardly such that said sealing lip is normally spaced from the shaft surface, said actuation ring having opposite first and second sides facing axially in inboard and outboard directions, said actuation ring resisting deformation when subjected to a first fluid pressure of sealed fluid acting on said inboard first side of said actuation ring, and said actuation ring being deformable radially inwardly when subjected to a second fluid pressure of sealed fluid greater than said first fluid pressure so as to collapse against the shaft surface to initially form the first seal by said settling lip contacting the shaft surface; and a metal sealing/anti-extrusion ring which provides a second seal during leakage, said metal ring including a sealing flange which projects radially inwardly so as to be normally spaced from the shaft surface when subjected to said first and second pressures, and is disposed axially adjacent to said actuation ring on said outboard second side, said sealing flange being stiffer than said actuation ring so as to be deformable against the shaft surface under increased sealed pressure loads generating a third fluid pressure of sealed fluid greater than said second fluid pressure, the polymer ring being pressed against the metal ring after deformation causing said metal ring to also deform so that an inside diameter of the metal ring comes into contact with the shaft surface to form the second seal.