摘要:
A seal arrangement for a rotary machine, such as a turbine, includes a main seal segment such as a labyrinth seal segment, a brush seal segment disposed in a slot in the main seal segment and having a layer of bristles secured between upstream and downstream plates of the brush seal segment, and at least one passage radially formed through the main seal segment to communicate a balancing pressure from a pressure source located exteriorly of an outer periphery of the main seal segment to a cavity defined in the downstream plate of the brush seal segment at a downstream side of the layer of bristles of the brush seal segment.
摘要:
A brush seal segment useful, when circumferentially arrayed with other such segments, to seal the gap between a rotor and a surrounding casing of a rotary machine such as a steam turbine. An annular backing plate has a rim radially-inwardly bounding together upstream-facing and downstream-facing surfaces. Canted bristles abut the upstream-facing surface. The rim is designed to allow the bristles to recover from a rotor rub. In one design, the rim acts as a labyrinth-seal tooth and is shaped to deform, under a radial force, longitudinally away from the upstream-facing surface. In another design, the rim has a more-inwardly projecting second portion near a radially-aligned edge, and only this second portion acts as a labyrinth-seal tooth.
摘要:
Circumferentially extending sealing segments (45) are disposed about a rotary component (16) and have seal face (34) carrying a plurality of labyrinth seal teeth (36) and a brush seal (37). The segments are movable between large and small clearance positions relative to the rotor at start-up and steady-state operating conditions, respectively. In one form, springs (31) bias the segments radially outwardly at start-up and steam pressure displaces the segments to the small clearance positions at steady-state operations. In a further embodiment, springs bias the segment for movement to the small clearance position, the extent of movement being determined by thermal expansion of centering rings mounting the segments to the stationary components.
摘要:
A method for overhauling a steam turbine to increase its power without increasing its overall length. Existing seal assemblies containing seals other than brush seals are replaced with longitudinally-shorter replacement seal assemblies having only brush seals. An existing turbine section, such as a high-pressure turbine section, is replaced with a longitudinally-longer replacement turbine section having additional stages (i.e., additional rows of rotating buckets or blades).
摘要:
A steam turbine having a shaft and a first (e.g., high-pressure) turbine section. A first embodiment also includes a first bearing longitudinally spaced apart from the first turbine section and further includes a first brush-seal assembly, having bristles, longitudinally positioned between the first turbine section and the first bearing and radially positioned proximate the shaft. The steam turbine is devoid of any backup seal to the bristles. In a second embodiment, a second brush seal assembly is positioned between the first and second (e.g., intermediate-pressure) turbine sections which lack any intervening bearing.
摘要:
Bucket covers for the buckets of a rotating component of a turbomachine are in radial opposition to a stationary component containing a circumferentially extending brush seal having bristles extending into engagement with sealing surfaces of the covers as the covers rotate by the bristles. The leading edges of the covers for the buckets in the plane of rotation and in the plane containing the brush seal have ramps or rounded surfaces which minimize the wear on the bristles and degradation of the performance of the seal as the bucket covers are rotated past the brush seal.
摘要:
A brush seal is comprised of arcuate seal segments having ends cut in a radial direction with bristles “canted” at an approximate 45° angle relative to radii of the segments, leaving triangular regions adjacent one end of each segment devoid of bristles at the segment interfaces. The brush seals are retrofit into conventional labyrinth seals with the backing plate for the bristles comprising a labyrinth tooth profile extending fully 360° about the seal, including those areas where bristles are not present. The sealing capacity is not substantially degraded, while affording significant sealing improvements over conventional labyrinth seals. Additionally, when retrofit into labyrinth seals with radial movement, the individual labyrinth seal segments are free to move radially independently of one another during transients.
摘要:
A brush seal is comprised of arcuate seal segments having ends cut in a radial direction with bristles “canted” at an approximate 45° angle relative to radii of the segments, leaving triangular regions adjacent one end of each segment devoid of bristles at the segment interfaces. The brush seals are retrofit into conventional labyrinth seals with the backing plate for the bristles comprising a labyrinth tooth profile extending fully 360° about the seal, including those areas where bristles are not present. The sealing capacity is not substantially degraded, while affording significant sealing improvements over conventional labyrinth seals. Additionally, when retrofit into labyrinth seals with radial movement, the individual labyrinth seal segments are free to move radially independently of one another during transients.
摘要:
Brush seals are retrofitted into existing turbine labyrinth seal rings to create a fail-safe seal design at locations wherever labyrinth seals are currently used, including interstage shaft seals, rotor end seals, bucket (or blade) tip seals and spill strips. Brush seals, per se, when used in place of labyrinth seals, can result in considerable span reductions of steam turbines, or machines with more turbine stages for a given span. Application to end packings results in the potential elimination of gland sealing/exhauster systems. Brush seal life can be improved by retrofitting brush segments to labyrinth seal segments that are either spring-backed, or use pressure loads to obtain design clearances only after steady state operating conditions are achieved. The brush seals are provided with backing plates shaped like labyrinth teeth, resulting in a fail-safe design. Also, the use of existing labyrinth teeth as bristle backing plates results in a brush seal with diminished susceptibility to hysteresis when compared to conventional brush seal designs. Low friction coatings can also be used to reduce brush seal hysteresis. Incorporation of brush seals in labyrinth seal rings that are either spring-backed or held in place by pressure forces results in extremely low brush seal wear.
摘要:
A turbine brush seal protection device includes an annular substrate having an outer periphery and defining a slot open at the outer periphery. The slot is for receiving a portion of an annular brush seal of a gas turbine subassembly during installation of a gas turbine and such that the annular substrate at least partially covers the annular brush seal of the gas turbine subassembly. The annular substrate at the outer periphery and within the slot thereof is removably mounted to a stationary portion of the gas turbine subassembly. A turbine brush seal protection method includes the steps of providing the annular substrate, placing the annular substrate over a portion of an annular brush seal of a gas turbine subassembly such that the seal portion is inside the slot of the annular substrate during installation of a gas turbine and the annular substrate at least partially covers the annular brush seal of the gas turbine subassembly, mounting the annular substrate at the outer periphery and within the slot thereof to a stationary portion of the gas turbine subassembly, and removing the annular substrate from the stationary portion of the gas turbine subassembly before completion of installation of the gas turbine subassembly.