Endface gap sealing for steam turbine diaphragm interstage packing seals and methods of retrofitting

摘要

Spline seals are disposed in circumferentially registering slots of adjacent arcuate packing seal segments disposed in grooves on inner hooks of a steam turbine diaphragm assembly. The spline seals extend in a gap between the endfaces of the segments and minimize or preclude steam leakage flows past the endfaces. The spline seals may be oriented in axial and circumferential directions to minimize leakage flow paths in a generally radial direction and/or may be inclined radially in a downstream direction to seal against steam leakage flow in an axial direction. The spline seals are disposed in the slots which may be formed as part of original equipment manufacture or may be machined in segments with spline seals provided as retrofits.