Rotary kinetic fluid motors or pumps – Bearing – seal – or liner between runner portion and static part – Labyrinth seal
Reexamination Certificate
1999-12-17
2001-04-24
Lopez, F. Daniel (Department: 3745)
Rotary kinetic fluid motors or pumps
Bearing, seal, or liner between runner portion and static part
Labyrinth seal
C416S205000
Reexamination Certificate
active
06220815
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to inter-stage seal retainers used in gas turbine engine assemblies and, more particularly, to inter-stage seal retainers and assemblies to mount inter-stage turbine seals to nozzles or vane assemblies of gas turbine engines.
2. Discussion of the Background Art
Conventional turbine inter-stage seal retainers are often installed in assemblies that are configured such that they cannot be visually reviewed by the assembler after installation and after complete torquing of the attaching bolt and nut of the retainer. As a result, if too much relative rotation between the retainer and the item to be retained, such as a seal assembly in a turbine section of a gas turbine engine, is allowed, improper assembly is possible. Improper assembly includes having the retained part being clamped inadvertently in the bolted joint or for it to be damaged by the retainer upon application of clamp force due to the bolt during torquing.
The seal assembly in the turbine is intended to be able to translate relative to a nozzle stage of the turbine and the retainer is used to maintain its mounting to the nozzle while allowing limited axial movement.
In the past, proper retainer installation relied upon the experience and feel of the assembler. Radially extending tabs welded on nut cages of the retainer were also used to “fool proof” or insure proper orientation and installation of the retainer.
SUMMARY OF THE INVENTION
A retainer which, in an exemplary embodiment of the invention, is used in a gas turbine engine inter-stage seal assembly to retain an annular seal ring flange of a seal ring against an annular platform flange extending radially inwardly from an inner platform of an annular nozzle stage having nozzle vanes. The retainer includes a body having a central portion through which a bore is formed around a bore axis and a central tab extends radially outwardly from the central portion with respect to the bore axis. First and second arms, respectively, extend in opposite respective first and second tangential directions, with respect to the bore axis, away from the central portion and each other. Axial spacers extending aftwardly from first and second free ends of the first and second arms, respectively, and anti-rotation feet depend from the first and second free ends in an opposite direction from which the central tab extends. A pedestal assembly extends aft from the central portion and is located aft of the central tab. In the exemplary embodiment, the pedestal assembly has a semi-annular cylindrical inner surface and a semi-annular cylindrical outer surface circumscribed around the bore axis wherein the semi-annular cylindrical outer surface extends between generally parallel spaced apart radially inner and outer flats, respectively, with respect to the bore axis, and the radially inner flats are coplanar and the radially outer flats are coplanar. Chamfers are formed along the radially inner and outer flats, respectively. The retainer is an integrally cast unit including the body, the central portion, the central tab, the first and second arms, the axial spacers, the anti-rotation feet, and the pedestal assembly.
In the exemplary embodiment, the pedestal assembly includes first and second mirror image pedestals, respectively, extending aft from the central portion. The first and second pedestals are semi-annular in shape and includes the semi-annular cylindrical outer surface and the cylindrical inner surface which is semi-annular and extends between the inner and outer flats. The anti-rotation feet preferably have rounded ends. The cylindrical inner surface is substantially continuous with a bore surface inside of the bore. The central tab is flush with a flat central aft facing surface of the central portion.
The present invention provides various improvements and advantages over the prior art. The chamfers on the pedestals and the axial location of central tab provide a combination of “fool proofing” and a better angle of installing the pedestals of the retainer in the slots of the seal flange. The shape of the pedestals together with the chamfers provide a more repeatable and accurate seating of the retainer and the pedestals disposed through the slots so as to prevent improper clamping which could cause the pedestals to fail. The rounded ends of the anti-rotation feet provide improved insertion of the pedestals in the slot and proper seating of the retainer as well as improved anti-torquing capabilities.
REFERENCES:
patent: 4767267 (1988-08-01), Salt et al.
patent: 5211541 (1993-05-01), Fledderjohn et al.
patent: 5343694 (1994-09-01), Toborg et al
patent: 5848874 (1998-12-01), Heumann et al.
patent: 5921749 (1998-12-01), McLaurin et al.
GE Aircraft Engines “CF6-80C2 Engine Manual”, Low Pressure Trubine Stator/Pressure Balance Seal Assembly, Oct. 1, 1995.
GE Aircraft Engines “CF6-80C2 Engine Illustrated Parts Catalog”, GE Engine Services Distribution, L.L.C., Sep. 1, 1999.
Barber Daniel J.
Cody William E.
Maue Gregory P.
McMahan Kevin W.
Rainous Edward A.
General Electric Company
Herkamp Nathan D.
Hess Andrew C.
Lopez F. Daniel
McAleenan James M.
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