Seal for a joint or juncture – Seal between fixed parts or static contact against... – Contact seal for other than internal combustion engine – or...
Reexamination Certificate
1999-01-11
2001-02-27
Knight, Anthony (Department: 3626)
Seal for a joint or juncture
Seal between fixed parts or static contact against...
Contact seal for other than internal combustion engine, or...
C277S644000, C415S135000, C415S138000
Reexamination Certificate
active
06193240
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to static seal structures. In particular, the invention relates to static seals for turbines, such as gas and steam turbines.
Seals are used between nozzle segments in turbines, engines, and other similar devices to prevent fluid flow between the segments. One known static seal assembly
101
for a nozzle segment is illustrated in FIG.
1
. The seal assembly
101
comprises a metallic seal
100
, which is an essentially flat, un-curved piece of metal. The metallic seal
100
defines generally flat, contact regions
104
. The metallic seal
100
fits into grooves
102
in nozzle segments
103
. The metallic seal
100
bridges a gap
105
formed by the grooves
102
and seals against the nozzle segments
103
at the contact regions
104
. Thus, the seal assembly
101
reduces leakage at the grooves
102
.
The above-described seal assembly
101
reduces leakage, however these seal assemblies depend on differential pressure to seal at the contact regions
104
. The differential pressure is applied across the metallic seal
100
in direction
120
to force the contact regions
104
against the nozzle segments
103
. The differential pressure maintains the contact regions
104
against the nozzle segments
103
. The differential pressure against the metallic seal
100
may not always be sufficient for maintaining sealing pressure. Thus, these prior art seal assemblies may result in an inadequate seal.
Further, the differential pressure may vary due to operation of the turbine. Thus, the contact region
104
may not be forced with sufficient sealing pressure to be positioned and form a seal against the nozzle segments
103
. The lack of sufficient sealing pressure is further apparent when the nozzle segments
103
move with respect to each other. The movement may result from one nozzle segment moving direction
103
, regardless of the movement's cause. The generally flat, contact regions
104
do not move and may not remain in contact with the nozzle segments due to their flat configuration. Accordingly, the prior art metallic seal
100
may not exhibit an adequate seal against the nozzle segments
103
.
Therefore, a static seal assembly that provides for enhanced sealing pressure is desirable. Additionally, a seal assembly that provides enhanced sealing pressure, regardless of differential pressure across it, is needed.
SUMMARY OF THE INVENTION
An exemplary embodiment of the invention provides a seal assembly that is adapted to be inserted into a groove to seal a gap formed by the groove. The seal assembly comprises a seal body, a biasing element, and a connection that connects the seal body to the biasing element to form the seal assembly. The seal assembly further comprises a concave-shaped center section and convex-shaped contact portions at each end of the seal body. The biasing element is formed from an elastic material and comprises a convex-shaped center section and concave-shaped biasing zones at each end of the biasing element that are opposed to the convex-shaped contact portions. The biasing element is adapted to be compressed to change a width of the seal assembly from a first width to a second width that is smaller than the first width. In the compressed state, the seal assembly can be disposed in the groove. After release of the compressing force, the seal assembly expands. The contact portions will move toward a surface of the groove and the biasing zones will move into contact with another surface of the groove. The biasing zones will bias the contact portions of the seal body against the surface of the groove to seal against the surface.
These and other aspects, advantages and salient features of the invention will become apparent from the following detailed description, which, when taken in conjunction with the annexed drawings, where like parts are designated by like reference characters throughout the drawings, disclose embodiments of the invention.
REFERENCES:
patent: 4537024 (1985-08-01), Grosjean
patent: 5158430 (1992-10-01), Dixon et al.
patent: 5249920 (1993-10-01), Shepherd et al.
patent: 5577472 (1996-11-01), Banta
patent: 5865600 (1999-02-01), Mori et al.
Johnson Roger Neal
Longfritz William David
General Electric Company
Johnson Noreen C.
Knight Anthony
Peavey Enoch E.
Stoner Douglas E.
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