摘要:
A combined labyrinth/brush seal is provided in a seal between rotating and stationary components. The seal includes a plurality of arcuate sealing segments, each having one or more labyrinth teeth extending radially toward the surface of the rotating component. As original equipment or retrofit, a brush seal is provided among the labyrinth teeth in a slot formed in the sealing face of the seal segment. In one form, backing and/or forward plates for the brush seal have a tongue extending into an axially extending groove of the seal segments to prevent relative radial movement of the brush seal and seal ring segments. The end faces of the brush seal and seal ring segments may be bored and filled with weld material to prevent relative circumferential movement. Where a single radially extending slot is provided in the sealing ring segment, the brush seal may be stitch-welded to the seal ring segment along opposite sides of the brush seal.
摘要:
A combined labyrinth/brush seal is provided in a seal between rotating and stationary components. The seal includes a plurality of arcuate sealing segments, each having one or more labyrinth teeth extending radially toward the surface of the rotating component. As original equipment or retrofit, a brush seal is provided among the labyrinth teeth in a slot formed in the sealing face of the seal segment. In one form, backing and/or forward plates for the brush seal have a tongue extending into an axially extending groove of the seal segments to prevent relative radial movement of the brush seal and seal ring segments. The end faces of the brush seal and seal ring segments may be bored and filled with weld material to prevent relative circumferential movement. Where a single radially extending slot is provided in the sealing ring segment, the brush seal may be stitch-welded to the seal ring segment along opposite sides of the brush seal.
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:
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 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 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 brush seal is comprised of arcuate seal segments having ends cut in a radial direction with bristles "canted" at an approximate 45.degree. 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.degree. 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 labyrinth brush seal combination for a rotating machine comprising an arcuate segment of predetermined axial extent carrying a plurality of axially spaced, circumferentially and radially extending tapered seal teeth, and at least one circumferentially extending array of discrete bristles carried by the segment at a predetermined axial location therealong and projecting beyond the radial extent of the teeth, the bristles having an elongated, flexible carrier strip slidably and removably received within a slot in the segment.
摘要:
A number of sealing segments 20 mounts a brush seal about a rotor. The tips of the brush seal 46 are maintained out of contact with the rotor surface throughout the entire operating range of the turbomachinery. Thus, the increase in temperature resultant from rubs between the bristle tips and the rotor 12 which effectively increase vibrations of the turbomachinery are eliminated. Brush seals are therefore maintained out of contact with the rotor throughout the entire operating range of the turbomachinery and thus do not affect the dynamic behavior of the rotor.