Abstract: A low pressure turbine casing has a conical annular shell circumscribed about a centerline. A forward flange depends from a forward end of the annular shell and a forward hook extends aftwardly from the forward flange. First and second rails having first and second hooks, respectively, extend aftwardly from the annular shell. First and second cooling holes extend through the first and second rails, respectively. Cooling air feed holes extend through the forward flange. The first and second cooling holes may be radially disposed through the first and second rails, respectively, with respect to the centerline or disposed through the first and second rails at an oblique angle with respect to the centerline. A low pressure turbine casing and shroud assembly further includes a first annular cavity in fluid flow communication with the first cooling holes and the second cooling holes. A second annular cavity is in fluid flow communication with the first and second cooling holes.

Abstract: A low pressure turbine casing has a conical annular shell circumscribed about a centerline. A forward flange depends from a forward end of the annular shell and a forward hook extends aftwardly from the forward flange. First and second rails having first and second hooks, respectively, extend aftwardly from the annular shell. First and second cooling holes extend through the first and second rails, respectively. Cooling air feed holes extend through the forward flange. The first and second cooling holes may be radially disposed through the first and second rails, respectively, with respect to the centerline or disposed through the first and second rails at an oblique angle with respect to the centerline. A low pressure turbine casing and shroud assembly further includes a first annular cavity in fluid flow communication with the first cooling holes and the second cooling holes. A second annular cavity is in fluid flow communication with the first and second cooling holes.

Abstract: A low pressure turbine shroud includes a backplate and abradable material attached to said backplate. The backplate includes an upstream end, a downstream end, and a body extending between the upstream end and the downstream end. The body includes a first portion and a second portion. The body first portion has a first thickness greater than a body second portion second thickness. The abradable material attaches to an inner surface of the backplate and includes at least one segment having a thickness greater than remaining segments of abradable material.

Abstract: Apparatus for controlling the clearance between the tips of a row of rotor blades and an array of surrounding shroud segments in a gas turbine engine. A torque tube is rotatably mounted on the engine casing and has a cam positioned inside the casing. First and second members are positioned inside the casing so as to be only axially moveable and so as to have their cam-engaging surfaces axially surround the cam, and they are biased such that the cam-engaging surfaces engage the cam. A shroud hanger, to which a shroud segment may be attached, includes axially spaced apart hooked flanges positioned to be engaged by hooked flanges of the first and second members. The flanges have axially inclined slide surfaces for such engagement, and the shroud hanger is biased radially inward to engage such slide surfaces. Clearance is controlled by rotation of the torque tube which axially moves the first and second members which radially moves the shroud segment.