U.S. patent application number 10/968959 was filed with the patent office on 2006-04-27 for grouped reaction nozzle tip shrouds with integrated seals.
This patent application is currently assigned to General Electric Company. Invention is credited to Robert James Bracken, David Orus Fitts, Ronald Wayne Korzun, Mark William Kowalczyk.
Application Number | 20060088409 10/968959 |
Document ID | / |
Family ID | 36143517 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060088409 |
Kind Code |
A1 |
Bracken; Robert James ; et
al. |
April 27, 2006 |
Grouped reaction nozzle tip shrouds with integrated seals
Abstract
A reaction turbine stator vane segment comprising an integral
grouping of plural vanes, an arcuate tip shroud connected between
radially inner tips of the vanes, and an arcuate mounting portion
extending across radially outer tips of the vanes, the arcuate tip
shroud formed with plural seal components extending radially
inwardly from the tip shroud.
Inventors: |
Bracken; Robert James;
(Niskayuna, NY) ; Fitts; David Orus; (Ballston
Spa, NY) ; Korzun; Ronald Wayne; (Clifton Park,
NY) ; Kowalczyk; Mark William; (Amsterdam,
NY) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
36143517 |
Appl. No.: |
10/968959 |
Filed: |
October 21, 2004 |
Current U.S.
Class: |
415/170.1 |
Current CPC
Class: |
F16J 15/4472 20130101;
Y10T 29/37 20150115; F01D 11/001 20130101; F05D 2240/56 20130101;
F16J 15/3288 20130101 |
Class at
Publication: |
415/170.1 |
International
Class: |
F04D 29/08 20060101
F04D029/08 |
Claims
1. A reaction turbine stator vane segment comprising an integral
grouping of plural vanes, an arcuate tip shroud connected between
radially inner tips of the vanes, and an arcuate mounting portion
extending across radially outer tips of the vanes, said arcuate tip
shroud formed with plural seal components extending radially
inwardly from said tip shroud.
2. The reaction turbine stator vane segment of claim 1 wherein said
plural seal components include a combination of strip seals and
brush seals.
3. The reaction turbine stator vane segment of claim 1 wherein said
plural seal components include a combination of labyrinth seal
teeth and brush seals.
4. The reaction turbine stator vane segment of claim 1 wherein said
plural seal components include a pair of strip seals, one on either
side of a brush seal.
5. The reaction turbine stator vane segment of claim 1 wherein said
plural seal components include a pair of labyrinth seal teeth, one
on either side of a brush seal.
6. The reaction turbine stator vane segment of claim 1 wherein said
plural seal components are mounted in an arcuate insert and said
arcuate insert is received within a groove in said tip shroud.
7. The reaction turbine stator vane segment of claim 6 wherein said
plural seal components include a brush seal flanked by a pair of
labyrinth seal teeth.
8. The reaction turbine stator vane segment of claim 1 wherein said
integral grouping is machined from a single solid block.
9. The reaction turbine stator vane segment of claim 1 wherein said
plural seal components include a brush seal insert received in a
groove in said tip shroud, with additional seal components on
opposite sides of said brush seal insert.
10. The reaction turbine stator vane segment of claim 9 wherein
said additional seal components comprise strip seals.
11. The reaction turbine stator vane segment of claim 9 wherein
said additional seal components comprise labyrinth seal teeth.
12. A reaction turbine stator vane segment comprising a unitary
machined grouping of plural vanes, an arcuate tip shroud connected
between radially inner tips of the vanes, and an arcuate mounting
portion extending across radially outer tips of the vanes, said
arcuate tip shroud formed with plural seal components extending
radially inwardly from said tip shroud, wherein said plural seal
components include a brush seal insert received in a groove in said
tip shroud, with additional seal components on opposite sides of
said brush seal.
13. The reaction turbine stator vane segment of claim 12 wherein
said additional seal components comprise strip seals mounted in a
radially inner face of the tip shroud.
14. The reaction turbine stator vane segment of claim 12 wherein
said additional seal components comprise labyrinth seal teeth
integrally formed with a radially inner face of the tip shroud.
15. The reaction turbine stator vane segment of claim 12 wherein
said additional seal components are mounted in said brush seal
insert.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to steam turbines having seals
between rotating and non-rotating components, and more
particularly, to seal configurations incorporated into integral tip
shrouds of grouped stator vanes in a reaction turbine.
[0002] Each stage of a reaction steam turbine includes a plurality
of circumferentially spaced buckets mounted on a drum rotor
surrounded by a plurality of stationary reaction stator vanes. The
buckets and nozzles form one stage of the turbine, and define the
main steam flow path. By way of contrast, in an impulse turbine,
the buckets are mounted on the periphery of rotor wheels and the
nozzle partitions are supported in surrounding diaphragms. It is
highly desirable in any case to minimize or eliminate as many steam
leakage paths as possible that stem from the main steam flow
path.
[0003] One source of leakage in a reaction turbine is a radial gap
between grouped sets of reaction stator vanes provided with
integral tip shrouds, and opposed radially outer portions of the
rotor. One known technique for sealing this radial gap involves the
utilization of insertable strip seals on the rotor that oppose seal
lands on the reaction stator tip shrouds that have been sprayed
with an abradable coating. Another prior technique involves the
incorporation of radially projecting labyrinth teeth at the inner
free ends of the nozzle or stator vanes that form labyrinth seals
with radially opposed component parts of the turbine rotor. See,
for example, commonly owned U.S. Pat. No. 6,786,699. The
combination of labyrinth seal teeth with brush seals has also been
utilized at the interface between diaphragm inner webs at the
radially inner ends of nozzle partitions and rotor lands in impulse
turbines. See, for example, commonly owned U.S. Pat. No. 6,669,443
and commonly owned U.S. Pat. No. 6,290,232.
[0004] There remains a need, however, for effective seal
configurations for use with grouped reaction turbine stator vanes
having integral tip shrouds that will effectively reduce the radial
gap between the tip shrouds and the opposed rotor lands.
BRIEF DESCRIPTION OF THE INVENTION
[0005] The present invention is directed toward novel seal
configurations for grouped reaction stator vane segments with
integral tip shrouds. The exemplary embodiments relate to
integrated one-piece stator vane segments incorporating multiple
vanes and seal configurations that may include a combination of
strip seals, brush seals or integral seal teeth that oppose rotor
seal lands in the assembled steam turbine.
[0006] For purposes of this invention, the term "grouped reaction
stator vanes with integral tip shrouds" refers to a plurality (2 or
more, and up to about 50) of reaction turbine stator vanes with
integral cover shrouds that have been grouped together by machining
as a one-piece or unitary group, where two or more groups make up a
360.degree. ring; or by welding or brazing individual vanes to form
a group, where two or more groups also make up a 360.degree.
ring.
[0007] In a first configuration, a machined one-piece stator vane
segment includes a plurality of vanes, integral tip shroud and
integral dovetail (or other mounting configuration). The stator tip
shroud extends over the plurality of vanes, connecting the tips
thereof, and is provided with a generally centered insert. The
insert includes a brush seal, and the insert is flanked by
conventional caulked strip seals upstream and downstream of the
brush seal. In a second exemplary configuration, the integral
stator tip shroud is provided with a generally axially centered
(i.e., in a flow direction) insert having a brush seal with
integral machined labyrinth seal teeth located upstream and
downstream of the insert. In a third configuration, the stator tip
shroud is machined to include a dovetail slot into which a seal
strip assembly may be inserted. The insertable seal strip assembly
is provided with an axially centered brush seal with integral
labyrinth seal teeth upstream and downstream of the brush seal.
[0008] For all of the configurations, the opposed rotor surface may
be machined to include a high-low-high land configuration or, a
low-high-low land configuration to match a similar seal arrangement
in the tip shrouds. In addition, the specific number of seals,
opposed seal lands, and choice of specific seals and/or combination
of seals may vary based upon specific application.
[0009] Accordingly, the present invention in its broader aspects
relates to a reaction turbine stator vane segment comprising an
integral grouping of plural vanes, an arcuate tip shroud connected
between radially inner tips of the vanes, and an arcuate mounting
portion extending across radially outer tips of the vanes, the
arcuate tip shroud formed with plural seal components extending
radially inwardly from the tip shroud.
[0010] In another aspect, the invention relates to reaction turbine
stator vane segment comprising a unitary machined grouping of
plural vanes, an arcuate tip shroud connected between radially
inner tips of the vanes, and an arcuate mounting portion extending
across radially outer tips of the vanes, the arcuate tip shroud
formed with plural seal components extending radially inwardly from
the tip shroud, wherein the plural seal components include a brush
seal insert received in a groove in the tip shroud, with additional
seal components on opposite sides of the brush seal.
[0011] The invention will now be described in detail in connection
with the drawings identified below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a grouped reaction stator
vane segment;
[0013] FIG. 2 is a partial end elevation of a grouped reaction
stator vane segment incorporating a seal configuration in
accordance with a first exemplary embodiment of the invention;
[0014] FIG. 3 is a partial end elevation of a grouped reaction
stator vane segment incorporating a seal configuration in
accordance with a second exemplary embodiment of the invention;
and
[0015] FIG. 4 is a partial end elevation of a grouped reaction
stator vane segment incorporating a seal configuration in
accordance with a third exemplary embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] With reference to FIG. 1, a grouped reaction stator vane
segment 10 includes a plurality of reaction vanes 12, an integral,
arcuate tip shroud 14 at the radially inner ends of the vanes, and
a dovetail or other mounting configuration 14 at the radially outer
ends of the vanes. While the figure shows a group of four vanes 12,
it is to be understood that the segment may include other numbers
of vanes, for example, 6, 8, 12, up to as many as 50 vanes or more,
the latter forming a 180.degree. segment. Together, two or more
such segments form a closed 360.degree. ring of reaction vanes.
[0017] In the preferred arrangement, the segment 14 is machined
from a single block of metal material, preferably a stainless steel
alloy, but individual vanes may also be grouped by welding, brazing
or other suitable means to form a segment.
[0018] Turning now to FIG. 2, the segment 10 and, specifically, the
tip shroud 14 is provided with a combined strip and brush seal
arrangement. Specifically, a brush seal insert 16 is slidably
received within a groove 18 formed in a radially inner face 19 of
the tip shroud 14. The insert incorporates brush seal elements 20
that extend radially inward to a location closely adjacent a land
22 on the turbine rotor 24. A pair of strip seals 26, 28 are seated
in respective grooves 30, 32 in the face 19 of the tip shroud on
opposite sides of the brush seal insert, and secured by, for
example, peening. These strip seals extend inwardly with the tips
closely adjacent respective lands 34, 36 of the rotor 24. Note that
the strip seals 26, 28 lie, respectively, upstream and downstream
of the generally axially centered brush seal 16 (relative to the
direction of steam flow), in a high-low-high arrangement vis-a-vis
the turbine lands. It will be understood that the turbine land
configuration could be reversed, with appropriate relocation of
seal tips in a low-high-low configuration.
[0019] FIG. 3 illustrates an alternative arrangement in connection
with a reaction stator vane segment 38. In this embodiment, the tip
shroud 40 is fitted with a generally axially centered brush seal
insert 42, seated in a groove 43 formed in the radially inner face
44 of the tip shroud, with brush seal elements 45 similar to the
insert 16 in FIG. 2. Labyrinth seal teeth 46, 48, respectively, are
formed integrally with the tip shroud 40 and lie upstream and
downstream of the brush seal insert 42, interacting with lands 50
and 52 on the rotor 54. The brush seal elements 44 extend inwardly
to a turbine land 56. Here again, a high-low-high land
configuration is illustrated but, as in the case of FIG. 2, that
configuration may be reversed to a low-high-low arrangement.
[0020] FIG. 4 illustrates yet another embodiment of the invention
where the reaction vane segment 58 includes an integrated tip
shroud 60, the radially inner face 61 of which is formed with a
dovetail-like groove 62 that receives a seal strip assembly insert
64. The insert 64 is provided with a generally axially centered
brush seal 66 having brush seal elements 68 that extend inwardly to
a location closely adjacent the turbine land 70. The insert 64 is
also formed with integrated upstream and downstream labyrinth seal
teeth 72, 74 which extend radially inwardly to a location closely
adjacent respective lands 76, 78 of the rotor 80. As in the prior
embodiments, the high-low-high land configuration may be reversed
to a low-high-low configuration, with suitable modification of the
sealing elements. It will be appreciated that the labyrinth seal
teeth 72, 74 could be replaced with strip seals similar to those in
FIG. 2.
[0021] The above-described seal configurations reduce the radial
gap between the rotor and the reaction stator vane tip shrouds, and
at the same time reduce assembly time for the rotor and eliminate
the need for an abradable coating on the reaction stator's integral
tip shroud. It will be appreciated that the tip shrouds may
incorporate seals and/or seal inserts with any combination of strip
seals, brush seals, or labyrinth seal teeth.
[0022] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *