Stator vane asssembly for an axial flow rotary machine

A stator assembly for an axial flow rotary machine having an axis of rotation, an annular flowpath for working medium gases, a casing outwardly of the flowpath and an array of stator vanes extending radially inward from the casing across the working medium flowpath, which comprises:

• A. a plurality of stator vanes each having an inner platform which extends circumferentially and which has a side region spaced from the side region of the inner platform of the adjacent vane leaving a circumferential clearance gap G therebetween, the inner platform having
• 1. an upstream flange having a circumferentially extending groove facing in an axial direction, the groove being bounded by an axially extending surface which faces radially outward,
• 2. a downstream flange spaced axially from the upstream flange leaving a circumferentially extending channel therebetween, the downstream flange having a circumferentially extending groove facing in the opposite axial direction, the groove being bounded by an axially extending surface which faces radially outward;
• B. an inner air seal having a circumferentially extending element which extends axially between the flanges to bound the channel, the element having an upstream leg which extends into the upstream groove of the upstream flange and a downstream leg which extends into the downstream groove of the downstream flange, each of the legs having an outwardly facing surface which overlaps the inwardly facing surface of the leg and adapts the leg to slidably engage the flange, the flanges and the legs cooperating to restrict movement of the inner air seal beyond an acceptable amount in the radial and axial directions;
• C. a circumferentially extending spring disposed in the channel which urges the inner air seal radially inwardly into abutting contact with the vane, the spring having a circumferentially extending base and two circumferentially extending joined to the base arms which are inclined toward each other,
• 1. the base in the uninstalled condition being bowed toward the arms and in the installed condition being less bowed to cause the base to contact the adjacent surface of the vane,
• 2. each arm being attached to an axial end of the base such that the spring member has a height h.sub.f in the uninstalled condition and a height h.sub.i in the installed condition which is less than the height h.sub.f,
• 3.

A stator assembly for an axial flow rotary machine having an axis of rotation, a case outwardly of a working medium flowpath and an array of stator vanes extending inward therefrom, which comprises:

• a stator vane having an inner end and a surface which is adapted to slidably engage a seal segment, the inner end including an inner platform which extends circumferentially and which is spaced from the adjacent stator vanes leaving a circumferential gap G therebetween;
• a seal segment which extends circumferentially with respect to the axis of rotation, which slidably engages the inner end of the stator vane in the circumferential direction and which axially overlaps the inner end of the stator vane and has a surface which is adapted to slidably engage the stator vane;
• means for urging the seal segment in the radial direction which is slidable on at least the stator vane or the seal segment and which exerts a radial force on the seal segment and on the stator vane such that the surface of the seal segment abuttingly engages the surface on the stator vane and is slidable thereon in a non-radial direction to provide frictional damping to the stator vane and to the inner air seal;
• wherein the means extends across the gap G between the vanes to block the leakage of working medium fluid gases from the working medium flowpath.