Abstract: Apparatus and method for minimizing and maintaining substantially constant the effective blade tip clearance between the outer free ends of rotor blades and an adjacent casing shroud of an axial-flow turbine of a gas turbine engine. The casing shroud includes a portion facing the hot gas stream and the outer rotor blade ends and a packing of high heat-resistance, high erosion-resistance ceramic elements secured to the shroud via a metal ring to face the blade tips. A heat insulator is interposed between the packing and the metal ring. A perforated conduit is mounted outside the metal ring for blowing cooling fluid against the metal ring on the side thereof remote from the insulator for equalizing the expansion of the metal ring to that of the turbine wheel. The ceramic packing includes projections facing the outer ends of the blades which are tapered so that they are easily broken off when coming into contact with the blades during running-in of the apparatus.

Abstract: An annular sleeve surrounds a turbine rotor and is fixed to a stationary part, the sleeve being elastically deformable in a radial direction. A wear ring is carried by the sleeve, the wear ring being composed of segments arranged end-to-end circumferentially. The adjacent ends of the segments are spaced apart at all operating conditions of the turbine. The thermal expansions of the turbine rotor and of the sleeve and ring are so related that under operating conditions of the turbine, when the engine of which it forms a part is running, the sleeve thermally expands radially. The rate of thermal expansion of the stationary part is directly related to the rate of thermal expansion of the turbine rotor. Air leaving the compressor is directed against the sleeve and the stationary part carrying the sleeve. The wear ring and portion carrying the sleeve may be insulated. The sleeve may be mounted on a combustion chamber surrounding the turbine.

Abstract: An annular sleeve surrounds a turbine rotor and is fixed with respect to the turbine casing, the sleeve being elastically deformable in a radial direction. A wear ring is carried by the sleeve, the wear ring being composed of segments arranged end-to-end circumferentially. The adjacent ends of the segments are spaced apart when the turbine is cold or idling. The thermal expansions of the turbine rotor and of the sleeve and ring are so related that in one operating temperature range of the turbine the spaces between the adjacent ends of the ring segments close and the segment ends engage each other, and in a higher operating temperature range of the turbine the sleeve expands. Air leaving the compressor is directed against the sleeve and the stationary part carrying the sleeve. The wear ring and portion carrying the sleeve may be insulated. The sleeve may be mounted on a combustion chamber surrounding the turbine.