U.S. patent application number 13/771135 was filed with the patent office on 2013-10-31 for separable seal assembly for a gas turbine engine.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to David William Crall, Andrew Mark Del Donno, Jason Francis Pepi, Richard Alan Wesling.
Application Number | 20130287551 13/771135 |
Document ID | / |
Family ID | 48182815 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130287551 |
Kind Code |
A1 |
Del Donno; Andrew Mark ; et
al. |
October 31, 2013 |
SEPARABLE SEAL ASSEMBLY FOR A GAS TURBINE ENGINE
Abstract
A seal assembly for sealing a rotatable shaft in a gas turbine
engine, wherein the shaft includes sections of greater shaft
diameter located both forward and aft of the seal shaft coupling
point is provided. The seal assembly includes a first semi-annular
segment with a first end, a second end, and a plurality of seal
teeth, where the first and second ends each include an overlap
joint. The seal assembly also includes a second semi-annular
segment with a first end, a second end, and a plurality of seal
teeth, where the first and second ends each include an overlap
joint. The first end of the second segment is coupled to the first
end of the first segment, and the second end of the second segment
is coupled to the second end of the first segment.
Inventors: |
Del Donno; Andrew Mark;
(Wakefield, MA) ; Crall; David William; (Loveland,
OH) ; Pepi; Jason Francis; (North Andover, MA)
; Wesling; Richard Alan; (Cincinnati, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY |
Schenectady |
NY |
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
48182815 |
Appl. No.: |
13/771135 |
Filed: |
February 20, 2013 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61639403 |
Apr 27, 2012 |
|
|
|
Current U.S.
Class: |
415/170.1 |
Current CPC
Class: |
F01D 11/02 20130101;
F01D 25/00 20130101 |
Class at
Publication: |
415/170.1 |
International
Class: |
F01D 25/00 20060101
F01D025/00 |
Claims
1. A seal assembly for sealing a rotatable shaft in a gas turbine
engine comprising: The rotatable shaft comprising sections of
greater shaft diameter located both forward and aft of the seal
shaft coupling point, said seal assembly comprising: a first
semi-annular segment comprising a first end, a second end, and a
plurality of seal teeth, said first and second ends each including
an overlap joint; and a second semi-annular segment comprising a
first end, a second end, and a plurality of seal teeth, said first
and second ends each including an overlap joint, said first end of
said second segment being coupled to said first end of said first
segment, and said second end of said second segment being coupled
to said second end of said first segment.
2. The seal assembly of claim 1 further comprising: a seal coupled
to a first shaft, the seal being separable from the shaft and
including at least two segments; the seal being capable of being
installed or removed on a complete shaft without a need to provide
clearance on either end of the shaft; the at least two segments
facilitating installation of the seal on the shaft to include
shafts having a greater diameter on both sides of a seal
installation point, thereby providing a multiplicity of choices for
location of the seal with respect to the shaft.
3. A seal assembly for sealing a rotatable shaft in a gas turbine
engine comprising: The shaft comprising sections of greater shaft
diameter located both forward and aft of the seal shaft coupling
point, said seal assembly comprising: a first half circle-shaped
segment and a second half circle-shaped segment; the first segment
including a first end having a connector and a second end having a
connector; and, the second segment including a first end having a
connector and a second end having a connector.
4. The seal assembly of claim 3 further comprising: The first
segment and the second segment being assembled by an overlap joint,
wherein mating connectors and, are joined with co-mating
connectors; and, the overlap joint thereby allowing the seal to
carry a hoop load.
5. The seal assembly of claim 4 further comprising segments, each
segment including a plurality of seal teeth.
6. The seal assembly of claim 5 further comprising a primary
retention for the seal being an interference fit between seal and a
shoulder of shaft wherein the first segment includes a shoulder
that enables secondary axial and tangential retention on the
shaft.
7. The seal assembly of claim 6 further comprising the assembly of
the first and second segments and about the shaft being
accomplished by heating both the first and the second segments to a
predetermined temperature, sliding first segment in from a side of
shaft, and sliding second segment axially such that the connectors
of one segment engage the mating halves of connectors on the other
segment, respectively.
8. The seal assembly of claim 7 further comprising allowing
temperature to equalize within the shaft thereby providing an
interference fit being generated between first and second segments
and shaft; the first and second segments enabling the ring formed
by their coupling to carry hoop stress; the first and second
segments being secured together by a retaining ring that is
expanded into a slot; an alignment pin being placed in an alignment
orifice that is disposed between the first and second segments;
and, the retaining ring being installed last, thereby securing the
alignment pin.
9. A seal assembly for sealing a rotatable shaft in a gas turbine
engine comprising: the shaft comprising sections of greater shaft
diameter located both forward and aft of the seal shaft coupling
point; and, said seal assembly comprising a first inner ring
segment, a second inner ring segment, a first outer ring segment,
and a second outer ring segment.
10. The seal assembly of claim 9 further comprising the first outer
ring segment and the second outer ring segment coupled together
about first and second inner ring segments and wherein the outer
ring segments and each include a plurality of seal teeth.
11. The seal assembly of claim 10 further comprising the primary
retention of seal being accomplished by an interference fit to
shaft, and secondary axial retention being accomplished by
protrusions on the inner diameter of seal on either side of a
shoulder of shaft.
12. The seal assembly of claim 11 further comprising that secondary
tangential retention is provided by a tab which engages with a
keyway on the shaft; The four ring segments are coupled along two
360 degree seams between the segments; and, the segments being
coupled by a securing method chosen from the group welding,
brazing.
13. The seal assembly of claim 12 further comprising that an
initial assembly of first and second segments and about shaft is
accomplished by: heating both first and second inner ring segments;
sliding first inner ring segment in from the side, and sliding
second inner ring segment axially such that connector engages the
mating half of connector, while a corresponding set of connectors
engages in a similar fashion on the other side of the seal; and,
When allowed to equalize in temperature with shaft, an interference
fit is generated between first and second inner ring segments and
shaft, enabling segments to carry hoop stress.
14. The seal assembly of claim 13 further comprising that following
the initial assembly steps of claim 13: two 180 degree segments
being the first outer ring segment and the second outer ring
segment, are coupled to the ring created by first and second inner
ring segment; the 180 degree segments being welded in place wherein
the weld joint is formed along two 360 degree seams between the
outer ring segments, and the inner ring segments; and, Seal teeth
are finish machined following assembly and welding of segments
thereby ensuring that tooth alignment and tip runout requirements
are met.
15. A seal assembly for sealing a rotatable shaft in a gas turbine
engine comprising: the shaft comprising sections of greater shaft
diameter located both forward and aft of the seal shaft coupling
point; and, said seal assembly comprising a plurality of identical
segments.
16. The seal assembly of claim 15 further comprising the plurality
being four identical segments connected to the shaft by a dovetail
joint and wherein each segment includes a plurality of seal
teeth.
17. The seal assembly of claim 16 further comprising that assembly
of segments about the shaft is accomplished by: inserting the
segments through a load slot formed in the shaft; and, rotating the
segments around the load slot, repeating until all segments are in
place.
18. The seal assembly of claim 17 further comprising installing a
set screw through a tapped hole located in each segment.
19. The seal assembly of claim 18 wherein the set screw engages
with a dimple in shaft thereby providing secondary retention.
20. The seal assembly of claim 15 wherein each segment has formed
upon it a dovetail pressure face over a central 50% of its arc
length, thereby allowing a corresponding reduction in the size of
the load slot.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/639403, filed Apr. 27, 2012, which is
incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The field of the invention relates generally to gas
turbines, and more particularly to methods and a system for a seal
assembly for an inter-shaft seal in a gas turbine engine.
[0003] Labyrinth seals are widely used on rotatable shafts to
regulate secondary air flows and provide a radial clearance between
low speed shafts and high speed shafts in gas turbine engines.
Generally, in more detail, the seals include a series of parallel
teeth that facilitate regulating a flow past the teeth and
capturing any excess oil. The tips of the teeth provide the
clearance between the two shafts. Newer generation engines include
shafts made of strong, but brittle materials that may not be as
tolerant of the rubbing that typical seal teeth endure during
engine operation. The rubbing can cause localized micro-cracking in
the shaft. Seals made of a single unit that are integral to the
shaft may not be allowable in some situations due to material or
stress concerns. Additionally, sections of greater shaft diameter
located both forward and aft of the seal can prevent implementation
of the seal on an unbroken ring of material. Accordingly, a seal
that is separable and not subject to the torque load of the shaft,
which results in greater flexibility in design at a lower cost for
repair and maintenance is desirable.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In one aspect, a seal assembly for sealing a rotatable shaft
in a gas turbine engine, wherein the shaft includes sections of
greater shaft diameter located both forward and aft of the seal
shaft coupling point is provided. The seal assembly includes a
first semi-annular segment with a first end, a second end, and a
plurality of seal teeth, where the first and second ends each
include an overlap joint. The seal assembly also includes a second
semi-annular segment with a first end, a second end, and a
plurality of seal teeth, where the first and second ends each
include an overlap joint. The first end of the second segment is
coupled to the first end of the first segment, and the second end
of the second segment is coupled to the second end of the first
segment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a cross-sectional view of an exemplary gas turbine
engine assembly for use in propelling an aircraft.
[0006] FIG. 2 is an enlarged cross-sectional view of the exemplary
seal shown in FIG. 1 in relation to the first and second
shafts.
[0007] FIG. 3 is a perspective view of an exemplary seal in
accordance with the present invention.
[0008] FIG. 4 is a cross-sectional view of the seal on the first
shaft taken at line 4-4 in FIG. 3.
[0009] FIG. 5 is a perspective view of an alignment pin connecting
the two segments of the seal shown in FIGS. 3 and 4.
[0010] FIG. 6 is a perspective view of an alternate embodiment of
the seal in accordance with the present invention.
[0011] FIG. 7 is a cross-sectional view of the seal on the first
shaft taken at line 7-7 in FIG. 6.
[0012] FIG. 8 is a perspective view of an alternate embodiment of
the seal in accordance with the present invention.
[0013] FIG. 9 is a cross-sectional view of the seal on the first
shaft taken at line 9-9 in FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
[0014] The following detailed description illustrates an
inter-shaft seal and a method of assembling the same by way of
example and not by way of limitation. The description enables one
of ordinary skill in the art to make and use the disclosure, and
the description describes several embodiments of the disclosure,
including what is presently believed to be the best mode of
carrying out the disclosure. The disclosure is described herein as
being applied to a preferred embodiment, namely, an inter-shaft
seal and a method of assembling the same. However, it is
contemplated that this disclosure has general application to shaft
seals in a broad range of systems and in a variety of industrial
and/or consumer applications.
[0015] FIG. 1 is a cross-sectional view of an exemplary gas turbine
engine (GTE) 10. GTE 10 includes a fan assembly 12, a core gas
turbine engine section 14 coupled downstream from fan assembly 12,
and a low-pressure turbine 16 coupled downstream from the core gas
turbine engine section 14. In the exemplary embodiment, core gas
turbine engine section 14 includes a multi-stage booster compressor
18, a high-pressure compressor 20, a combustor 22, and a
high-pressure turbine 24. GTE 10 also includes an inlet 26 and an
exhaust 28. In the exemplary embodiment, low-pressure turbine 16
and booster compressor 20 are coupled together via a first drive
shaft 30, and compressor 18 and high-pressure turbine 24 are
coupled together via a second drive shaft 32.
[0016] In operation, air is drawn into engine inlet 26, and
compressed through booster compressor 18 and high pressure
compressor 20. The compressed air is channeled to combustor 22
where it is mixed with fuel and ignited to produce air flow through
high pressure turbine 24 and low pressure turbine 16, and exits
through exhaust 28.
[0017] FIG. 2 is an enlarged cross-sectional view of the gas
turbine engine shown in FIG. 1. GTE 10 includes a seal 34 coupled
to first shaft 30. Seal 34 is separable from shaft 30 and includes
at least two segments such that it may be installed or removed on a
complete shaft without needing clearance on either end of the
shaft. Moreover, being made of at least two segments facilitates
installation of seal 34 on a shaft even when the shaft has a
greater diameter on both sides of seal 34 installation point, which
provides much greater flexibility in where seal 34 is located on a
shaft. Seal 34 may include, as desired, labyrinth tooth material of
the same material, or different material, as/than the shaft 30,
respectively. Seal 34 may be coupled to shaft 30 in multiple ways,
which are described below.
[0018] FIG. 3 is a perspective view of an exemplary seal 34 in
accordance with the present invention. Seal 34 includes a first
half circle-shaped segment 300 and a second half circle-shaped
segment 302. First segment 300 includes a first end having a
connector 304 and a second end having a connector 306. Second
segment 302 includes a first end having a connector 308 and a
second end having a connector 310. First segment 300 and second
segment 302 assemble by an overlap joint, by joining connectors 304
and 308, and connectors 306 and 310. The overlap joint allows seal
34 to carry a hoop load. Segments 300 and 302 each include a
plurality of seal teeth 312.
[0019] FIG. 4 is a cross-sectional view of seal 34 (shown in FIG.
3) coupled to a shaft taken at line 4-4 in FIG. 3. In the exemplary
embodiment, the shaft is shaft 30 (shown in FIG. 1). The primary
retention for seal 34 is an interference fit between seal 34 and a
shoulder 400 of shaft 30. First segment 300 includes a shoulder 402
(shown in FIG. 3) that enables secondary axial and tangential
retention on shaft 30.
[0020] Assembly of first and second segments 300 and 302 about
shaft 30 is accomplished by heating both first and second segments
300 and 302 to a predetermined temperature, sliding first segment
300 in from a side of shaft 30, and sliding second segment 302
axially such that connectors 308 and 310 engage the mating halves
of connectors 304 and 306, respectively. When allowed to equalize
in temperature with shaft 30, an interference fit is generated
between first and second segments 300 and 302 and shaft 30. First
and second segments 300 and 302 enable the ring formed by their
coupling to carry hoop stress. To hold first and second segments
300 and 302 together, a retaining ring 404 is expanded into a slot
406. Moreover, with reference to FIG. 5, an alignment pin 500 is
placed in an alignment orifice 502 formed between first and second
segments 300 and 302 (shown in FIGS. 3 and 4). Alignment pin 500 is
then trapped by the retaining ring, which is installed last.
[0021] FIG. 6 is a perspective view of an alternative embodiment of
seal 34 in accordance with the present invention. Seal 34 includes
first inner ring segment 600, second inner ring segment 602, first
outer ring segment 604, and second outer ring segment 606. First
and second inner ring segments 600 and 602 are similar to first and
second segments 300 and 302, as described in FIGS. 3-5, less the
retaining ring, and are coupled to a shaft in the same manner. Seal
34 also includes first outer ring segment 604 and second outer ring
segment 606 coupled together about first and second inner ring
segments 600 and 602. Outer ring segments 604 and 606 each include
a plurality of seal teeth 608.
[0022] FIG. 7 is a cross-sectional view of seal 34 on shaft 30
(shown in FIG. 1) taken at line 7-7 in FIG. 6. The primary
retention of seal 34 is accomplished by an interference fit to
shaft 30, and secondary axial retention is accomplished by
protrusions 701 on the inner diameter of seal 34 on either side of
a shoulder 700 of shaft 30. Secondary tangential retention is
provided by a tab 702 which engages with a keyway 704 on shaft 30.
The four ring segments 600, 602, 604, and 606 are coupled along two
360 degree seams 708 between the segments. Segments 600, 602, 604,
and 606 may be coupled by welding and brazing.
[0023] Assembly of first and second segments 600 and 602 about
shaft 30 is accomplished by heating both first and second inner
ring segments 600 and 602, sliding first inner ring segment 600 in
from the side, and sliding second inner ring segment 602 axially
such that connector 610 engages the mating half of connector 612,
and another set of connectors (not shown) engage on the other side
of seal 34. When allowed to equalize in temperature with shaft 30,
an interference fit is generated between first and second inner
ring segments 600 and 602 and shaft 30, enabling segments 600 and
602 to carry hoop stress. Following this initial assembly step, two
180 degree segments, first outer ring segment 604 and second outer
ring segment 606, are coupled to the ring created by first and
second inner ring segments 600 and 602, and welded in place. The
weld joint is formed along the two 360 degree seams between outer
ring segments 604 and 606, and inner ring segments 600 and 602.
Seal teeth 608 are finish machined following assembly and welding
of segments 600, 602, 604, and 606 to ensure tooth alignment and
tip runout requirements are met.
[0024] FIG. 8 is a perspective view of an alternate embodiment of
seal 34 in accordance with the present invention. FIG. 9 is a
cross-sectional view of separable seal 34 on a shaft taken at line
9-9 in FIG. 8. Seal 34 is comprised of a plurality of identical
segments 800. In the exemplary embodiment, seal 34 includes four
identical segments 800. Segments 800 are connected to shaft 30
(shown in FIG. 1) by a dovetail joint. Segments 800 each include a
plurality of seal teeth 802.
[0025] Segments 800 are assembled about shaft 30 (shown in FIG. 1)
by inserting them through a load slot 804 in shaft 30. Segments 800
are then rotated around load slot 804 until all segments 800 are in
place. For each segment 800, a set screw (not shown) is installed
through a tapped hole 806 located in each segment 800. The screw
engages with a dimple 900 in shaft 30 to provide secondary
retention. Each segment 800 has only a dovetail pressure face over
the central 50% of its arc length, allowing load slot 804 to be
smaller in size.
[0026] The seal assembly described herein enables installation of a
separable seal on a shaft where integral teeth and/or a one piece
ring are not usable. The seal assembly provides a 360 degree ring
that can be installed on a completed shaft without needing
clearance on either end for installation. The assembly provides
different connection options depending on the specifications
required.
[0027] While multiple inventive embodiments have been described and
illustrated herein, those of ordinary skill in the art will readily
envision a variety of other means and/or structures for performing
the function and/or obtaining the results and/or one or more of the
advantages described herein, and each of such variations and/or
modifications is deemed to be within the scope of the invent of
embodiments described herein. More generally, those skilled in the
art will readily appreciate that all parameters, dimensions,
materials, and configurations described herein are meant to be
exemplary and that the actual parameters, dimensions, materials,
and/or configurations will depend upon the specific application or
applications for which the inventive teachings is/are used. Those
skilled in the art will recognize, or be able to ascertain using no
more than routine experimentation, many equivalents to the specific
inventive embodiments described herein. It is, therefore, to be
understood that the foregoing embodiments are presented by way of
example only and that, within the scope of the appended claims and
equivalents thereto, inventive embodiments may be practiced
otherwise than as specifically described and claimed. Inventive
embodiments of the present disclosure are directed to each
individual feature, system, article, material, kit, and/or method
described herein. In addition, any combination of two or more such
features, systems, articles, materials, kits, and/or methods, if
such features, systems, articles, materials, kits, and/or methods
are not mutually inconsistent, is included within the inventive
scope of the present disclosure.
[0028] Examples are used to disclose the embodiments, including the
best mode, and also to enable any person skilled in the art to
practice the apparatus and/or method, including making and using
any devices or systems and performing any incorporated methods.
These examples are not intended to be exhaustive or to limit the
disclosure to the precise steps and/or forms disclosed, and many
modifications and variations are possible in light of the above
teaching. Features described herein may be combined in any
combination. Steps of a method described herein may be performed in
any sequence that is physically possible.
[0029] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms. The indefinite articles "a" and "an," as used
herein in the specification and in the claims, unless clearly
indicated to the contrary, should be understood to mean "at least
one." The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
[0030] It should also be understood that, unless clearly indicated
to the contrary, in any methods claimed herein that include more
than one step or act, the order of the steps or acts of the method
is not necessarily limited to the order in which the steps or acts
of the method are recited.
[0031] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," "composed of," and
the like are to be understood to be open-ended, i.e., to mean
including but not limited to. Only the transitional phrases
"consisting of" and "consisting essentially of" shall be closed or
semi-closed transitional phrases, respectively, as set forth in the
United States Patent Office Manual of Patent Examining Procedures,
Section 2111.03.
* * * * *