GB1295025A - - Google Patents

Abstract

1295025 Gas turbines WESTINGHOUSE ELECTRIC CORP 19 April 1971 [23 April 1970] 23594/71 Headings FIT and F1G The turbine of a gas turbine engine includes an inter-stage seal assembly 21 defining an annular cooling air chamber 22 between rotor discs 15 and comprising an annular housing member 23 having an axially extending portion 24 defining a labyrinth seal 29 with the rotor and a radially extending flange 25 sealingly engaging surface 27 of projections 26 on the inner shroud segments 13 of stator vanes 11 with freedom for radial expansion. Angularly spaced bolts 43 extend through flange 25 to support at their forward ends two staggered layers of thin sheet metal segments 31 defining one end of chamber 22. Circumferentially adjacent segments 31 are spaced slightly apart to permit expansion and each segment engages a seal surface 32 on shroud segments 13 but is spaced a small distance 'B' from annular rotor surface 33 to limit leakage of cooling air. Segments 31 are spaced from flange 25 by spacers 44 each of which engages a shoulder 45 on the head of each bolt 43, a spring washer 46 being disposed between the respective segment 31 and the end of spacer 44. Thus the loading on segments 31 is limited so that they can slide relative to the bolt heads. The bolts 43 also support overlapping segments 34 on the downstream side of flange 25 which sealingly engage a surface 35 on housing member 23 and the surface 36 of shroud projections 26. Segments 34 include axially extending portions 37 defining a small clearance 'A' with projection 38 on rotor disc 15. Housing member 23 is held concentric with rotor axis 16 by six keys 52 mounted on some of the bolts 43 on the lower half of the housing member, the keys 52 being disposed in radial slots 53 in shroud projections 26. The keys 52 are adjustable by means of eccentric bushings 54 on the bolts 43.