Low-pressure turbine shroud

A turbine for a gas turbine engine having an inlet, an outlet and an annular passageway for gas flow from said inlet to said outlet, comprising;

• a) an outer casing surrounding said annular passageway, said outer casing having an annular groove;
• b) a nozzle stage arranged inside said outer casing and supported thereby, said nozzle stage comprising an outer platform having a shroud portion which forms a part of said annular passageway, said shroud portion having a forwardly projecting annular tip;
• c) a plurality of butted turbine shroud segments circumferentially arrayed to form a ring, each of said turbine shroud segments having a first, axially forward end seated in said annular groove of said outer casing and a second, axially aft end seated on a radially outer surface of said annular tip of said shroud portion;
• and
• d) spring means for urging said second, axially aft end of said shroud segment radially inwardly to bear against said radially outer surface of said annular tip of said shroud portion.

A turbine for a gas turbine engine having an inlet, an outlet and an annular passageway for gas flow from said inlet to said outlet, comprising;

• a) an outer casing surrounding said annular passageway, said outer casing having an annular groove;
• b) a nozzle stage arranged inside said outer casing and supported thereby, said nozzle stage comprising an outer platform having a shroud portion which forms a part of said annular passageway, said shroud portion having a forwardly projecting annular tip;
• c) a plurality of butted turbine shroud segments circumferentially arrayed to form a ring, each of said turbine shroud segments having a first end seated in said annular groove of said outer casing and a second end seated on a radially outer surface of said annular tip of said shroud portion;
• and
• d) spring means for urging said second end of said shroud segment radially inwardly to bear against said radially outer surface of said annular tip of said shroud portion;
• e) wherein said spring means is seated on said shroud segment and comprises
• i) a first plurality of circumferentially distributed resilient fingers which bear against a substantially radially inwardly facing surface of said outer casing, and
• ii) a second plurality of circumferentially distributed resilient fingers which bear against a substantially axially forwardly facing surface of said outer casing;
• and
• f) wherein said substantially radially inwardly facing surface and said substantially axially forwardly facing surface are surfaces of an annular flange projecting from said outer casing, said outer platform of said nozzle stage being hooked onto said annular flange of said outer casing.

A turbine for a gas turbine engine having an inlet, an outlet and an annular passageway for gas flow from said inlet to said outlet, comprising;

• a) an outer casing surrounding said annular passageway, said outer casing having an annular groove;
• b) a nozzle stage arranged inside said outer casing and supported thereby, said nozzle stage comprising an outer platform having a shroud portion which forms a part of said annular passageway, said shroud portion having a forwardly projecting annular tip;
• c) a plurality of butted turbine shroud segments circumferentially arrayed to form a ring, each of said turbine shroud segments having a first end seated in said annular groove of said outer casing and a second end seated on a radially outer surface of said annular tip of said shroud portion;
• d) spring means for urging said second end of said shroud segment radially inwardly to bear against said radially outer surface of said annular tip of said shroud portion;
• e) wherein each pair of adjacent shroud segments has opposing abutments with axial and radial seals arranged therebetween;
• f) wherein each of said shroud segments comprises a radially extending annular flange and a backing sheet, wherein said backing sheet comprises a substantially conical segment and an annular curved segment connecting the radially outer periphery of said radially extending annular flange with the portion of said substantially conical segment of said backing sheet having the maximum radius of curvature thereof, said radially extending annular flange, said substantially conical segment and said annular curved segment all forming a part of a continuous sheet of metal;
• and
• g) wherein each of said abutments having first slot means for receiving said axial seal and a second slot means for receiving said radial seal.