Apparatus and methods for removing and installing a selected nozzle segment of a gas turbine in an axial direction

A retention system for nozzles of a turbine, comprising:

• a nozzle retention ring for disposition about an axis of the turbine;
• a plurality of circumferentially adjacent nozzle segments carried by said nozzle retention ring;
• anti rotation pins extending in generally axial directions and engaging between said retention ring and said nozzle segments, respectively, to restrain movement of the nozzle segments in a rotational direction about the turbine axis;
• wherein said retention ring includes an axially facing surface, said anti rotation pins being exposed through said surface and at least one retention plate segment overlying the axially facing surface, precluding removal of the pins in an axially direction;
• and
• wherein said retention plate segment comprises one of a plurality of arcuate retention plate segments arranged in an annular array thereof about the axis, said arcuate retention plates being bolted to said retention ring.

A method of removing in an axial direction a selected nozzle segment of an annular array of nozzle segments forming a stage of a turbine from a retention ring carrying the annular array of nozzle segments, comprising the steps of:

• (a) removing in a generally axial direction substantially axially extending pins from a plurality of nozzle segments of the annular array thereof, including the selected nozzle segment, and said retention ring, thereby releasing nozzle segments adjacent said selected nozzle segment for sliding movement about an axis of the turbine in a circumferential direction away from the selected nozzle segment;
• (b) sliding the released nozzle segments adjacent said selected nozzle segment in a circumferential direction about the axis away from the selected nozzle segment;
• and
• (c) removing the selected nozzle segment in a generally axial direction.

A method of installing a selected nozzle segment into an opening in an annular array of nozzle segments for forming a stage of a turbine, comprising the steps of:

• (a) inserting the selected nozzle segment in a generally axial direction into said opening;
• (b) inserting a pin in an axial direction through the selected nozzle segment and the retention ring to secure the selected nozzle segment to the nozzle retention ring;
• (c) sliding nozzle segments adjacent the inserted selected nozzle segment in a circumferential direction toward said selected nozzle segment into predetermined circumferential positions about the turbine axis;
• and
• (d) securing said adjacent nozzle segments to said retention ring in said predetermined circumferential positions.