US 5,104,287 AGranted

Blade tip clearance control apparatus for a gas turbine engine

AssigneeGeneral Electric Company

InventorJohn J. Ciokajlo

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Abstract

A mechanical clearance control apparatus is operable for controlling the clearance between the rotor blade tips and the casing shroud of a gas turbine engine. The apparatus includes a shroud segment which defines a circumferential portion of the casing shroud and is disposed in an opening defined by a mounting section of the stationary casing, a channel defined between radially spaced portions of the shroud segment and the stationary casing mounting section, and a wave spring disposed in the channel and preloaded against the shroud segment and mounting section for biasing the shroud segment to move radially inward toward the rotor. Flanges on opposite sides of the shroud segment and on the stationary casing mounting section at opposite sides of the opening cooperate to define inner and outer limits of radial movement of the shroud segment as the shroud segment is moved toward and away from the rotor. A mechanism is rotatably mounted to the stationary casing mounting section, threadably coupled to the shroud segment and pivotaly linked to a unison ring for moving the shroud segment toward and away from the rotor to set the clearance between the shroud segment and the rotor blade tips upon rotational movement of the unison ring.

Claims9

Dependent claims

In a gas turbine engine including a rotatable rotor having a row of blades with outer tips and a stationary casing with a shroud and being disposed in concentric relation with said rotor, an apparatus for controlling the clearance between said rotor blade tips and casing shroud, said apparatus comprising:

(a) a shroud segment defining a circumferential portion of said casing shroud, being separate from and disposed in an opening defined in said stationary casing;
(b) a channel defined between radially spaced portions of said stationary casing and said shroud segment;
(c) means disposed in said channel and being preloaded against said spaced portions of said stationary casing and said shroud segment for biasing said shroud segment to move radially inwardly toward said rotor;
and
(d) a mechanism coupled to said shroud segment and said stationary casing and being operable for radially moving said shroud segment toward and away from said rotor to reach a selected position relative to said rotor at which a desired clearance is established between said shroud segment and said rotor blade tips, said mechanism further being operable for holding said shroud segment at said selected position to maintain said desired clearance between said shroud segment and said rotor blade tips;
(e) said mechanism including at least a pair of threaded drive members rotatably mounted to said stationary casing, said shroud segment including an elongated arcuate body and a pair of threaded connectors spaced from one another and fixedly attached on said arcuate body, said connectors threadably coupled to said drive members such that rotation of said drive members in one direction causes radial movement of said shroud segment toward said rotor, whereas rotation of said drive members in an opposite direction causes radial movement of said shroud segment away from said rotor.

3 more elements

Dependencies are inferred from the claim text.