STEAM TURBINE OVERSHROUD SEAL Russian patent published in 2003 - IPC

FIELD: mechanical engineering; turbines. SUBSTANCE: proposed seal contains sealing ring consisting of segments, each being made in form of cylindrical shell with one-piece turned tongues and T-shaped shank. Segments are arranged in T-shaped ring slot of stator part over shroud of working cascade. Support radial belts made at edges of shells from side of stator part are in contact with stator part, segments are made of material with linear expansion coefficient larger than that of stator part material and sufficient for pressing segments over support belts to stator part owing to thermal expansion of segments in process of operation of turbine. Shells of segments cover shroud of stage working cascade and tongues of shells form labyrinth of overshround seal with row of expansion chambers. Such design provides reliable operation of segments at high temperatures and density of steam making it possible to use segments with one-piece turned tongues for sealing working cascade of first stages of steam turbine. EFFECT: provision of high reparability of seal and effective labyrinth overshround sealing of stages in zones of high temperatures and density of steam. 3 cl, 1 dwg