Non-contacting gas seal for relatively rotating parts

Claim 1

A non-contacting seal for reducing fluid flow between relatively rotatable components of a machine comprises a seal ring having a sealing face, the seal ring being adapted to be disposed, in operation, on one of the components with its sealing face confronting a cooperating sealing face on the other component to form a seal therebetween, means for locating the seal ring in a housing with freedom of movement in a direction normal to said sealing faces, the seal ring being formed in a plurality of segments, each having a face which includes a sealing area and a lifting area, said sealing area forming part of the sealing face of the ring, and further means for providing a seal between the ring and the housing, characterised in that: the lifting area of each segment extends substantially from a leading end to a trailing end thereof, the leading end of each segment being arranged to overlap the trailing end of an adjacent segment in such a manner as to provide a step between the ends of the adjacent segments whereby, in use, a tapering gap which converges towards the trailing end of each segment is produced between at least the lifting area of each segment face and the confronting sealing face of said other component, said tapering gap for generating lift to maintain non-contact between at least the lifting area of each segment face and the confronting sealing face of said other component, and, means for maintaining the relative circumferential positions of the segments while allowing radial movements of the segments relative thereto.