| 摘要 |
In a gas turbine having a chordal hinge seal between an inner rail (52) of each nozzle segment and an annular axially facing sealing surface (54) of a nozzle support ring (44), a supplemental seal (70) is disposed between the support ring and inner bands of the nozzle segments on a lower pressure side of the chordal hinge seals. To minimize or prevent leakage flow across the chordal hinge seals, a generally U-shaped supplemental seal (70) having reversely folded U-shaped marginal portions (74) is received in a cavity formed in the axially extending sealing surface of the inner rail (52) of the nozzle segment. At operating conditions, the marginal portions (74) seal against the base of the cavity and the annular sealing surface (54) of the nozzle support ring to prevent leakage flow past the chordal hinge seal from entering the hot gas path. To install the supplemental seal, the seal is first compressed and maintained in a compressed state by applying one or more wraps about the supplemental seal or an epoxy to secure the seal when compressed in the cavity. At operating temperatures, the retention means releases the seal to engage marginal portions against opposite sealing surfaces of the nozzle segment and support ring. <IMAGE> |
