Patent ID: 7144015

Claim:
A tandem gas seal assembly for forming a seal between a rotor and a casing of a rotary machine, the tandem gas seal comprising: two sealing stages for mounting axially adjacent to one another in the rotary machine, each of the sealing stages comprising a rotating sub-assembly for mounting on the rotor and a stationary sub-assembly for mounting in the casing, wherein: each rotating sub-assembly includes a support sleeve mounted on the rotor, a rotating mating ring with a front face, a locking sleeve slideably mounted on top of the support sleeve and a fastener releasably securing the locking sleeve and the support sleeve to one another, a first end of the locking sleeve bearing against the front face of the mating ring thereby retaining the mating ring in the rotating sub-assembly; each rotating sub-assembly of the two sealing stages including the support sleeve is totally separable from one another and each stationary sub-assembly of the two sealing stages is totally separable from one another, each of the two stages is capable of functioning as a seal when separated from the other, and mating formations formed at adjacent axial ends of the rotating sub-assembly of the two sealing stages to maintain the two sealing stages in axial alignment with one another.