The composite seal structure includes a carrier ring and a seal element housed in an annular groove formed between a circumferential outer wall and two side walls of the carrier ring. The seal element has a first region in surface-to-surface contact with the annular groove and a second, seal-ing region protruding from the annular groove. A fastening arrangement couples the seal element and the carrier ring to one another. The fastening arrangement comprises a plurality of fastening pins circumferentially arranged around the axis of the carrier ring. Also disclosed is a method for manufacturing the seal structure.

A steam turbine has a diffuser that is configured to guide steam to an outside of a casing. The diffuser has an outer guide that gradually expands to an outer side in a radial direction and an inner guide that is disposed at intervals to an inner side in the radial direction with respect to the outer guide. The inner guide has an inner curved diameter-expanded portion that gradually expands to the outer side in the radial direction while being curved from the first side to the second side in the axial direction. The outer guide has a first diameter-expanded portion that gradually expands to the outer side in the radial direction with a first radius of curvature, and a second diameter-expanded portion that gradually expands to the outer side in the radial direction with a second radius of curvature larger than the first radius of curvature.

A steam turbine has a diffuser that is configured to guide steam to an outside of a casing. The diffuser has an outer guide that gradually expands to an outer side in a radial direction and an inner guide that is disposed at intervals to an inner side in the radial direction with respect to the outer guide. The inner guide has an inner curved diameter-expanded portion that gradually expands to the outer side in the radial direction while being curved from the first side to the second side in the axial direction. The outer guide has a first diameter-expanded portion that gradually expands to the outer side in the radial direction with a first radius of curvature, and a second diameter-expanded portion that gradually expands to the outer side in the radial direction with a second radius of curvature larger than the first radius of curvature.

A sealing device according to at least one embodiment includes not less than three arc-shaped fins arranged in an axial direction. The arc-shaped fins include: a first fin which is one of two outermost fins located on an outermost side in the axial direction; a second fin disposed adjacent to the first fin in the axial direction; and at least one third fin disposed opposite to the first fin across the second fin in the axial direction. It is preferable that the third fin is disposed to be inclined with respect to a radial direction such that a tip end portion is located on a side of the first fin in the axial direction relative to a base end portion, and the third fin has a larger inclination angle than the first fin or the second fin with respect to the radial direction.

A sealing device according to at least one embodiment includes not less than three arc-shaped fins arranged in an axial direction. The arc-shaped fins include: a first fin which is one of two outermost fins located on an outermost side in the axial direction; a second fin disposed adjacent to the first fin in the axial direction; and at least one third fin disposed opposite to the first fin across the second fin in the axial direction. It is preferable that the third fin is disposed to be inclined with respect to a radial direction such that a tip end portion is located on a side of the first fin in the axial direction relative to a base end portion, and the third fin has a larger inclination angle than the first fin or the second fin with respect to the radial direction.

A split labyrinth seal assembly having split stationary and rotary sealing elements, and a split clamping mechanism. The clamping mechanism is configured to secure the rotary element to a rotating shaft. The rotary element can also include an integrally formed valve element that moves between a contacting and a non-contacting position in response to rotation of the shaft. The rotary element and the clamping mechanism can have surface features associated therewith to promote nesting between the components.

A split labyrinth seal assembly having split stationary and rotary sealing elements, and a split clamping mechanism. The clamping mechanism is configured to secure the rotary element to a rotating shaft. The rotary element can also include an integrally formed valve element that moves between a contacting and a non-contacting position in response to rotation of the shaft. The rotary element and the clamping mechanism can have surface features associated therewith to promote nesting between the components.

A labyrinth seal, has: rotating and static components rotatable relative to one another relative to a central axis, the rotating component securable to a shaft via a tight fit engagement at an engagement location on the rotating component, the static component securable to a housing; teeth protruding from one of the rotating and static components towards a seal land defined by the other one of the rotating and static components; and clearances between the teeth and the seal land, a first clearance of the clearances greater than a second clearance of the clearances, the first clearance located closer to the engagement location of the rotating component than the second clearance.

A labyrinth seal, has: rotating and static components rotatable relative to one another relative to a central axis, the rotating component securable to a shaft via a tight fit engagement at an engagement location on the rotating component, the static component securable to a housing; teeth protruding from one of the rotating and static components towards a seal land defined by the other one of the rotating and static components; and clearances between the teeth and the seal land, a first clearance of the clearances greater than a second clearance of the clearances, the first clearance located closer to the engagement location of the rotating component than the second clearance.

A turbine section has: a rotor rotatable about a central axis, the rotor having blades each protruding radially outwardly from a platform relative to the central axis; a stator having vanes each protruding radially outwardly from a shroud; a rim seal between the platform and the shroud, the rim seal having: an axial overlap between the platform and the shroud, and a lip protruding in a direction having a radial component relative to the central axis from one of the platform and the shroud toward the other of the platform and the shroud, the lip axially overlapping the other of the platform and the shroud, the lip having a radial height such that a radial gap remains between the lip and the other of the platform and the shroud when the turbine section is in operation.