System for sealing an inner retainer segment and support ring in a gas turbine and methods therefor

A turbine comprising:

• a plurality of nozzle segments arranged about a turbine axis with each segment having at least one stator vane and an inner platform carrying an inner platform rail;
• inner nozzle support rings in part in spaced axial registration with said rails and on one axial side of said rails;
• a plurality of inner retainer segments secured to said inner supporting rings and in part in axial spaced registration relative to said rails on an axial side of said rails from said support rings;
• and
• a seal assembly between said inner retainer segments and said rails, said seal assembly including a plurality of circumferentially spaced inner retainer seals each including a plurality of circumferentially spaced seal fingers for sealing engagement with said rails, each said retainer seal including first and second sets of circumferentially adjacent seal fingers overlying one another and secured to each of said inner retainer segments, said first and second sets of fingers of each inner retainer seal having at least one gap between circumferentially adjacent fingers and said second set of seal fingers having at least one gap between circumferentially adjacent fingers thereof, said first and second sets of seal fingers being staggered in a circumferential direction relative to one another with a finger of said first set of fingers overlying the one gap between the circumferentially adjacent fingers of said second set thereof.

A method of installing a seal assembly in a turbine having a plurality of nozzle segments arranged about a turbine axis with each segment having at least one stator vane and an inner platform carrying an inner platform rail and inner nozzle support rings in part in spaced axial registration with said rails and on one axial side of said rails for sealing between high and low pressure regions on opposite sides of said rails, comprising the steps of:

• providing a plurality of inner retainer segments secured to said inner supporting rings and in part in axial spaced registration relative to said rails on an axial side of said rails opposite from said support rings;
• securing a plurality of circumferentially spaced inner retainer seals each including a plurality of circumferentially spaced seal fingers to said inner retainer segments;
• securing said inner retainer segments with said seals secured thereto to said support rings with said seals extending from said segments into sealing engagement with said rails on said axially opposite sides thereof from said support rings;
• providing first and second overlapping sets of said inner retainer seals with each set of seals having at least one gap between circumferentially adjacent fingers thereof, and staggering said first;
• and
• second sets of seals in a circumferential direction relative to one another enabling a finger of said first set of seals to overlie a gap between adjacent fingers of said second set of seals.