Combination seal for sealing between two machine parts

Abstract

For sealing between two opposed surfaces of two machine elements (1, 2) a combination seal is provided to be fitted into an open groove (3) in one of the machine elements (2). The seal comprises an electomeric expansion ring (4, 5) at the bottom of the groove (3), an intermediate ring (6) made of a viscous-elastic material, e.g. PTFE and having a sealing surface (6b) to contact the mating machine element (2), and an elastomeric outer ring (8) fitted into a separate groove (7) in the sealing surface (6b) of the intermediate ring. Especially in cases where the seal is to separate fluid and gas an improved distribution of the contact pressure at the sealing surface (6b) and also an effective hydrodynamic relief of the outer ring (8) preventing its exposure to injurious pressures and subsequent damage is obtained by designing the intermediate ring (6) at the ends of the sealing surface (6b) with comparatively sharp corners (16, 17), the parts of the sealing surface between these corners and the separate groove (7) forming conical faces (14, 15) which at a narrow slit angle converge towards the separate groove (7). The intermediate ring may also be biassed by the two expansion rings (4, 5) placed on each side of the separate groove (7).

Dependencies are inferred from the claim text.