U.S. patent application number 09/682335 was filed with the patent office on 2003-02-27 for transition piece side sealing element and turbine assembly containing such seal.
Invention is credited to Cromer, Robert Harold.
Application Number | 20030039542 09/682335 |
Document ID | / |
Family ID | 24739239 |
Filed Date | 2003-02-27 |
United States Patent
Application |
20030039542 |
Kind Code |
A1 |
Cromer, Robert Harold |
February 27, 2003 |
Transition piece side sealing element and turbine assembly
containing such seal
Abstract
The gas-path leakage seal is provided for generally sealing a
gas-path leakage-gap between spaced-apart first and second members
of a turbine. The seal includes an elongated seal member having an
elongated, imperforate, and flexible first portion and a rigid
second portion that defines a mounting bracket. The first portion
has first and second surfaces and raised longitudinal edges that
extend a generally identical distance above the first surface and
generally the aforesaid identical distance below the second
surface. A cloth layer having a thickness generally equal to or
slightly greater than the aforesaid identical distance is
superimposed on the second surface between the raised edges.
Inventors: |
Cromer, Robert Harold;
(Johnstown, NY) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
1100 N GLEBE ROAD
8TH FLOOR
ARLINGTON
VA
22201-4714
US
|
Family ID: |
24739239 |
Appl. No.: |
09/682335 |
Filed: |
August 21, 2001 |
Current U.S.
Class: |
415/135 ;
415/139 |
Current CPC
Class: |
F01D 11/005
20130101 |
Class at
Publication: |
415/135 ;
415/139 |
International
Class: |
F01D 011/00 |
Claims
1. A turbine seal comprising an elongated seal member having a
length and having opposing first and second ends bounding said
length, an elongated, imperforate, and flexible first portion, and
a rigid second portion lengthwise adjoining said first portion,
wherein said first portion is lengthwise disposed between said
first end and said second portion, wherein said second portion is
lengthwise disposed between said first portion and said second end,
wherein said flexible first portion includes a shim-layer
assemblage having opposing first and second surfaces and having two
longitudinally extending raised edge regions, wherein each of said
raised edge regions extends a generally identical distance above
said first surface and each of said raised edge regions extends
generally said identical distance below said second surface; and
wherein said flexible first portion further includes a cloth layer
assemblage having a thickness generally equal to or slightly
greater than said identical distance and superimposed on said
second surface between said raised edge regions, and wherein said
second portion defines a mounting bracket.
2. The turbine seal of claim 1, wherein said shim-layer assemblage
has a first thickness and includes at least first and second metal
strips, wherein said second portion has a second thickness and
comprises a metal plate, and wherein said second thickness is at
least five times greater than said first thickness.
3. The turbine seal of claim 1, wherein said second portion
includes a generally right-angle bend, and wherein said mounting
bracket is an angled mounting bracket.
4. The turbine seal of claim 1, wherein said cloth layer assemblage
is mechanically secured to said shim-layer assemblage.
5. The turbine seal of claim 4, wherein said cloth layer assemblage
is spot welded to said shim-layer assemblage.
6. The turbine seal of claim 4, wherein said second portion is
mechanically secured to corresponding sections of said shim-layer
and cloth layer assemblages of said first portion.
7. The turbine seal of claim 1, wherein said raised edge regions
are generally mirror images of each other.
8. The turbine seal of claim 1, wherein each of said raised edge
regions has a first portion disposed at said identical distance
above said first surface, wherein each of said raised edge regions
has a second portion disposed at said identical distance below said
second surface, and wherein each of said raised edge regions has a
connecting portion joining together said first and second portions,
and wherein in said cross section said connecting portion has a
curved shape.
9. A turbine assembly comprising: a) a first turbine member having
a first surface groove; b) a second turbine member proximate and
spaced apart from said first turbine member so as to define a
fluid-path leakage gap therebetween, said second turbine member
having a second surface groove facing and generally aligned with
said first surface groove; and c) a turbine seal including an
elongated turbine seal member having a length and having opposing
first and second ends bounding said length, an elongated,
imperforate, and flexible first portion, and a rigid second portion
lengthwise adjoining said first portion, wherein said first portion
is lengthwise disposed between said first end and said second
portion, wherein said second portion is lengthwise disposed between
said first portion and said second end, wherein said flexible first
portion includes a shim-layer assemblage having opposing first and
second surfaces and having two longitudinally extending raised edge
regions, wherein each of said raised edge regions extends a
generally identical distance above said first surface and each of
said raised edge regions extends generally said identical distance
below said second surface; and wherein said flexible first portion
further includes a cloth layer assemblage having a thickness
generally equal to or slightly greater than said identical distance
and superimposed on said second surface between said raised edge
regions, wherein said second portion defines a mounting bracket,
and wherein said turbine seal member is disposed in said gap with
said first edge engaged in said first surface groove and with said
second edge engaged in said second surface groove.
10. The turbine assembly of claim 9, wherein said shim-layer
assemblage has a first thickness and includes at least first and
second metal strips, wherein said second portion has a second
thickness and comprises a metal plate, and wherein said second
thickness is at least five times greater than said first
thickness.
11. The turbine assembly of claim 9, wherein said second portion
includes a generally right-angle bend, and wherein said mounting
bracket is an angled mounting bracket.
12. The turbine assembly of claim 9, wherein said cloth layer
assemblage is mechanically secured to said shim-layer
assemblage.
13. The turbine assembly of claim 12, wherein said cloth layer
assemblage is spot welded to said shim-layer assemblage.
14. The turbine assembly of claim 12, wherein said second portion
is mechanically secured to corresponding sections of said
shim-layer and cloth layer assemblages of said first portion.
15. The turbine assembly of claim 9, also including a third turbine
member, and wherein said mounting bracket defined by said second
portion is secured to said third turbine member.
16. The turbine assembly of claim 15, wherein said second portion
includes a generally right-angle bend, and wherein said mounting
bracket is an angled mounting bracket.
17. The turbine assembly of claim 16, wherein said turbine assembly
is a power-system gas turbine assembly, wherein said first and
second turbine members are circumferentially-adjacent transition
pieces of said gas turbine assembly, and wherein said third turbine
member is a first stage nozzle of said gas turbine assembly.
18. The turbine assembly of claim 16, further comprising a mounting
block for securing the mounting bracket to the third turbine
member, the mounting block having a bolt hole and the third turbine
member having a threaded bolt hole for receiving a common bolt to
secure the mounting block to the third turbine member.
19. The turbine assembly of claim 18, wherein the mounting block
includes first and second slots, the right-angle bend of the second
portion engaging one of said slots to secure the seal member to the
third turbine member.
20. The turbine assembly of claim 9, wherein each of said raised
edge regions has a first portion disposed at said identical
distance above said first surface, wherein each of said raised edge
regions has a second portion disposed at said identical distance
below said second surface, and wherein each of said raised edge
regions has a connecting portion joining together said first and
second portions, and wherein in said cross section said connecting
portion has a curved shape.
Description
BACKGROUND OF INVENTION
[0001] The present invention relates generally to seals, and more
particularly to a spline seal for a turbine.
[0002] Turbines include gas and steam turbines. Gas turbines
include, but are not limited to, gas turbine power generation
equipment and gas turbine aircraft engines.
[0003] A gas turbine has a gas path which typically includes, in
serial-flow relationship, an air intake (or inlet), a compressor, a
combustor, a turbine, and a gas outlet (or exhaust nozzle).
Gas-path leakage occurs through gaps between gas turbine
subassemblies such as through gaps between the combustor and the
turbine, and gas-path leakage occurs through gaps between the
components that make up a gas turbine subassembly, such as through
gaps between combustor casing segments. Such components and
subassemblies have surfaces of different shapes, suffer from
assembly misalignment, and undergo vibration. Hot-section
components thermally experience hot gas flow and typically undergo
different thermal growths.
[0004] Gas leakage, either out of the gas path or into the gas
path, from an area of higher pressure to an area of lower pressure,
is generally undesirable. For example, gas-path leakage in the
turbine or compressor area of a gas turbine, between the rotor of
the turbine or compressor and the circumferentially surrounding
turbine or compressor casing, will lower the efficiency of the gas
turbine leading to increased fuel costs. Additionally, gas-path
leakage in the combustor area of a gas turbine will require an
increase in burn temperature to maintain power level, such
increased burn temperature leading to increased pollution, such as
increased NOx and CO production.
[0005] Steam turbines (which can be considered a special type of
gas turbine) include, but are not limited to, steam turbine power
generation equipment. A steam turbine includes a steam inlet, a
turbine, and a steam outlet, wherein steam is the gas which turns
the turbine rotor. The turbine of a steam turbine is similar to the
turbine of a gas turbine and suffers from steam-path leakage the
way the turbine of a gas turbine suffers from gas-path leakage.
[0006] Seals are used to minimize leakage of fluids. A known
fluid-path leakage seal is a cloth seal having a generally
impervious and uniformly-thick shim assemblage and a cloth
assemblage generally surrounding the shim assemblage. Cloth seals
may be used in many applications including, but not limited to,
seal assemblies for steam turbines and gas turbines used for power
generation and seal assemblies for gas turbines used for aircraft
and marine propulsion.
[0007] Commonly owned U.S. Pat. No. 5,934,687 relates to a cloth
seal that incorporates a metal sheet having raised edges that are
pushed against the associated turbine members to provide improved
sealing. However, no provision is made for facilitating the quick
assembly of the seal to the turbine members, and thus the metal
sheet component design limits functional, manufacturing, and
assembly options.
[0008] Another fluid-path leakage seal for sealing the gap between
two circumferentially-adjacent (and non-rotating) transition pieces
of a power-system gas turbine is disclosed in commonly owned U.S.
Pat. No. 6,162,014. This seal is a manually-flexible metal seal
that has a uniform thickness in the general shape of an elongated
rectangular metal sheet, and has a fiber-fabric cloth layer wrapped
around the metal sheet. One elongated edge of the metal bar is
engaged in a surface groove of one transition piece. The other
elongated edge of the metal bar is engaged in a matching and
aligned surface groove of the other transition piece. One end of
the metal bar serves as a mounting bracket, having a right-angle
bend, which is used to secure the seal to a (non-rotating)
first-stage nozzle. The grooves of transition pieces are not
perfectly machined, and the grooves of transition pieces installed
in power-system gas turbines are not perfectly aligned. As a
result, in spite of the flexibility of the metal seal an effective
seal may not be achieved between the transition pieces. In
addition, the metal sheet component design limits functional,
manufacturing and assembly options.
[0009] What is needed is an leakage seal for a turbine that
improves upon the seals of the '687 and '014 seal configurations so
as to be easy to assemble and install, and so as to provide a more
effective seal between components that are not perfectly aligned,
and that increases functional, manufacturing and assembly
options.
SUMMARY OF INVENTION
[0010] The gas-path leakage seal according to an embodiment of the
invention is for generally sealing a gas-path leakage-gap between
spaced-apart first and second members of a turbine.
[0011] In one aspect, the turbine seal of the present invention
includes an elongated seal member having a length and having
opposing first and second ends bounding said length, an elongated,
imperforate, and flexible first portion, and a rigid second portion
lengthwise adjoining said first portion, wherein said first portion
is lengthwise disposed between said first end and said second
portion, wherein said second portion is lengthwise disposed between
said first portion and said second end, wherein said flexible first
portion includes a shim-layer assemblage having opposing first and
second surfaces and having two longitudinally extending raised edge
regions, wherein each of said raised edge regions extends a
generally identical distance above said first surface and each of
said raised edge regions extends generally said identical distance
below said second surface; and wherein said flexible first portion
further includes a cloth layer assemblage having a thickness
generally equal to or slightly greater than said identical distance
and superimposed on said second surface between said raised edge
regions, and wherein said second portion defines a mounting
bracket.
[0012] In an exemplary embodiment, the cloth layer assemblage and
the shim-layer assemblage are attached together by spot welds, and
the raised edges have curved portions.
[0013] In another aspect of the invention, a turbine assembly is
provided that includes a) a first turbine member having a first
surface groove; b) a second turbine member proximate and spaced
apart from said first turbine member so as to define a fluid-path
leakage gap therebetween, said second turbine member having a
second surface groove facing and generally aligned with said first
surface groove; and c) a turbine seal including an elongated
turbine seal member having a length and having opposing first and
second ends bounding said length, an elongated, imperforate, and
flexible first portion, and a rigid second portion lengthwise
adjoining said first portion, wherein said first portion is
lengthwise disposed between said first end and said second portion,
wherein said second portion is lengthwise disposed between said
first portion and said second end, wherein said flexible first
portion includes a shim-layer assemblage having opposing first and
second surfaces and having two longitudinally extending raised edge
regions, wherein each of said raised edge regions extends a
generally identical distance above said first surface and each of
said raised edge regions extends generally said identical distance
below said second surface; and wherein said flexible first portion
further includes a cloth layer assemblage having a thickness
generally equal to or slightly greater than said identical distance
and superimposed on said second surface between said raised edge
regions, wherein said second portion defines a mounting bracket,
and wherein said turbine seal member is disposed in said gap with
said first edge engaged in said first surface groove and with said
second edge engaged in said second surface groove.
[0014] Advantageously, in one embodiment, the turbine seal is
vibrationally excited within a range of vibrational frequencies by
motion of generally only the first and second turbine members
during operation of the turbine, and the turbine seal is devoid of
any resonant frequency within the range of vibrational
frequencies.
[0015] In an exemplary application, the turbine assembly is a
power-system gas turbine assembly, the first and second turbine
members are circumferentially-adjacent transition pieces, and the
mounting bracket is secured to a third turbine member comprising a
first stage nozzle.
[0016] Several benefits and advantages are derived from the
invention. The manually-flexible main body of the turbine seal
member allows all transition-piece turbine spline seals in a
standard power-system gas turbine to be replaced in generally half
a day instead of the several days required for prior-art seals.
Furthermore, manually flexible main body, which may be a metal
sheet, provides good sealing of gas flow as the raised edges are
pushed against the first and second turbine members by gas from the
higher-pressure side of the seal. The first cloth layer provides
some sealing and good wear resistance. The flexible metal sheet and
the inherent flexibility of the cloth layer provides good seal
flexibility which means the seal is very compliant and can
accommodate surfaces of different shapes, assembly misalignment,
vibration, and differential thermal growth. The spot welds make it
easier to assemble the seal, and the curved portions make it easier
to install the seal.
BRIEF DESCRIPTION OF DRAWINGS
[0017] FIG. 1 is a perspective view of a first embodiment of the
turbine seal of the present invention;
[0018] FIG. 2 is a top plan view of a seal strip embodying the
invention;
[0019] FIG. 3 is a cross-sectional view taken along line 3-3 of
FIG. 2;
[0020] FIG. 4 is a fragmentary view of the seal assembly of FIG. 1
illustrating an exemplary welding pattern;
[0021] FIG. 5 is a top plan view of the seal assembly of FIG.
1;
[0022] FIG. 6 is a side elevational view of the assembly of FIG.
5;
[0023] FIG. 7 is a view of a section of a turbine including a seal
assembly embodying the invention; and
[0024] FIG. 8 is a cross-sectional view taken along line 8-8 of
FIG. 7 showing the edges of the seal assembly engaged in the
surface groove of first and second turbine members in an embodiment
of the invention.
DETAILED DESCRIPTION
[0025] Referring now to the drawings, wherein like numerals
represent like elements throughout, FIG. 1 shows a first embodiment
of the turbine seal of the present invention. The turbine seal is
defined by an elongated turbine seal member 10 that has having a
length and first and second ends 12 and 14. The turbine seal member
includes an elongated, imperforate first portion 16 and also
includes a second portion 18 lengthwise adjoining the first
portion. In an exemplary embodiment, the first portion 16 defines
the main body of the seal member and is manually-flexible. The
second portion 18 defines a mounting bracket of the seal member and
is manually-rigid. By "manually-flexible" it is meant that the
first portion 16 can be flexed by hand by an adult person of
average strength. By "manually-rigid" it is meant that the second
portion 18 cannot be flexed by hand by an adult person of average
strength. The first portion is lengthwise disposed between the
first end and the second portion, the second portion is lengthwise
disposed between the first portion and the second end.
[0026] In a first embodiment, as seen in FIGS. 3, 5 and 6, the
first portion 16 is comprised of an imperforate shim-layer
assemblage 20 that has a first thickness and the second portion 18
is defined from a bent strip or plate 22 that has a second
thickness. In an exemplary embodiment, the second thickness is on
the order of at least about five times greater than the first
thickness.
[0027] The shim-layer assemblage comprises at least one shim layer
or plate of uniform thickness, and may comprise at least two
superimposed, generally identical shim layers or plates. In this
exemplary embodiment, the assemblage has no more than four layers.
Each shim layer is impervious to gas and comprises a metal,
ceramic, and/or polymer sheet. The choice of materials for the shim
and the choice of the thickness for a shim layer are made by the
artisan to meet the sealing, flexibility, and resilience
requirements of a particular seal application. Usually, the
shim-layer has a thickness of generally between about five and
twenty thousandths of an inch, for example, about ten thousandths
of an inch where two shim layers are provided. In one embodiment,
each shim layer comprises a high-temperature, cobalt-based
super-alloy, such as HS-188. It is noted that the shim layers can
comprise different materials and/or have different thicknesses
depending on the particular seal application.
[0028] In the illustrated embodiment, the first portion of the seal
member is comprised of two superimposed and identical shim layers
24, 124, formed from metal. To integrate the assembly, the first
end 12 of the seal member is edge-welded. Further, to facilitate
placement of the seal member, the first end 12 is chamfered as
shown at 26.
[0029] Thus, a flexible and generally imperforate shim-layer
assemblage 20 is provided having opposing first and second
surfaces, defined in the illustrated embodiment by the top surface
28 of shim plate 24 and the bottom surface 30 of shim plate 124,
respectively. The shim-layer assemblage further includes to raised
edges 32, 132. In the illustrated embodiment, one raised edge 32 is
formed entirely from one of the edges of one metal shim sheet 24,
and the other raised edge 132 is formed entirely from one of the
edges of another metal shim sheet 124. Each of the raised edges
extends a generally identical distance above the first surface 28,
and each of the raised edges extends generally that same identical
distance below the second surface 30. It is noted that the
directions "above" and "below" are relative directions applying to
the seal as viewed in FIGS. 1 and 3. In the illustrated embodiment,
the raised edges 32, 132 are generally mirror images of each
other.
[0030] As will be understood from the discussion above, in a first
exemplary embodiment, the shim-layer assemblage is an elongated
metal strip assemblage having a centerline running midway between
the raised edges and having a cross section (shown in FIG. 3)
generally perpendicular to the centerline. Here, each of the raised
edges has a first portion 34, 134 disposed at the
previously-defined generally identical distance above the first
surface 28 of the metal sheet assemblage, each of the raised edges
has a second portion 36, 136 disposed at the previously-defined
generally identical distance below the second surface 30. In the
previously-defined cross section the first portion has a curved
shape. Also, in the previously-defined cross-section the raised
edges each terminate proximate the second portion 36, 136.
Furthermore, each of the raised edges has a connecting portion 38,
138 joining together the first and second portions. The connecting
portions 38, 138 have a curved shape, more specifically a generally
bowed shape, pointing away from each other as illustrated in FIG.
3. Such curved bowed shape facilitates seal installation in many
seal applications, as described in greater detail below. In an
exemplary mode of making the seal, each sheet metal member is
stamped or rolled to form the curved raised edges. It is noted that
seal can be made by pressing seal between two pressing plates (not
shown).
[0031] The seal member further includes a cloth layer assemblage
40. In the illustrated embodiment, the cloth layer assemblage 40
has a thickness generally the same as or slightly greater than
(e.g. by the thickness of one of the metal sheets or shims
comprising the shim-layer assemblage) the previously defined
identical distance (i.e., the identical distance the first and
second raised edges extend above the first surface). The cloth
layer assemblage 40 is superimposed on the second surface between
the raised edges. The cloth layer assemblage comprises at least one
cloth layer, only one of which is shown in FIG. 3. Each cloth layer
comprises metal, ceramic, and/or polymer fibers that have been
woven, knitted, or pressed into a layer of fabric. The choice of
layer construction (i.e., woven, knitted, or pressed), the choice
of materials for the cloth, and the choice of the thickness for a
layer are made by the artisan to meet the wear resistance,
flexibility, and sealing requirements of a particular seal
application. It is noted that such multiple cloth layers can
comprise different materials, different layer construction (i.e.,
woven, knitted, or pressed) and/or have different thicknesses
depending on the particular seal application. In this exemplary
embodiment, the cloth layer assemblage has no more than two cloth
layers. In one embodiment, each cloth layer is a woven cloth layer
comprising L605 or Haynes-25. An exemplary cloth layer is a twilled
metal cloth layer. By "twilled" is meant a cloth having a twill
weave (such as a twill weave which floats weft threads over two
warp threads and which staggers these floats regularly). In an
exemplary construction, the cloth layer has 30 warp wires per inch
and 250 weft wires per inch with each warp and weft wire having a
thickness of 7-10 mils and with the cloth layer having an overall
thickness of about 0.052 inch. An exemplary cloth-layer assemblage
is a Dutch Twill weave cloth assemblage comprising a
high-temperature, cobalt-based super-alloy, such as L-605. It is
noted that a Dutch Twill weave will allow a small controlled
leakage which provides cooling, as can be appreciated by the
artisan.
[0032] In an exemplary embodiment, the cloth layer assemblage 40 is
superimposed on generally the entire second surface 30. In the
illustrated construction, the cloth layer assemblage 40 and the
metal shim-layer assemblage 20 are attached together by a plurality
of spot welds 42 (as shown in FIG. 4). In another examplary
construction, seam welds (not shown) are used in place of spot
welds.
[0033] Thus, the first portion 16 of the turbine seal member is
defined by its corresponding sections of the shim-layer and
cloth-layer assemblages. The second portion 18 of the turbine seal
member 10 includes a base portion 44 lengthwise overlapping the
corresponding section of the cloth-layer assemblage 40 of the first
portion and attached (such as by spot welding 46) to the
corresponding sections of the cloth-layer and shim-layer
assemblages. The second portion 18 of the turbine seal member 10,
which may be made of stainless steel, includes a generally
right-angle bend 48 to define mounting bracket 22 having a support
portion 50 adjoining the base portion 44.
[0034] FIGS. 7 and 8 schematically show a first embodiment of the
gas-path leakage seal of the present invention. Although the
invention is described in terms of a gas turbine, it is understood
to be equally applicable to a steam turbine, which can be
considered a special type of gas turbine. The gas-path leakage seal
is for generally sealing a gas-path leakage-gap between
spaced-apart first and second members of a gas turbine (only a
small portion of which is shown in FIG. 7). The turbine assembly
includes a first turbine member 52, a second turbine member 54
which is proximate and circumferentially spaced apart from the
first turbine member so as to define a fluid-path leakage gap 56
therebetween, and a turbine seal 10 embodying the invention. The
first turbine member 52 has a first surface groove or slot 58, and
the second turbine member has a second surface groove or slot 60
facing and generally aligned with the first surface groove 58. A
fluid-path leakage gap as used herein includes, without limitation,
a steam-path leakage gap of a turbine of a steam turbine, a
compressed-air leakage gap of a compressor of a gas turbine, and a
combustion-gas leakage gap in or downstream of a combustor of a gas
turbine. In a power-system gas turbine, downstream of the combustor
includes the transition pieces, first-stage nozzle and turbine
sections.
[0035] The turbine seal 10 is identical to the previously-described
turbine seal shown in FIGS. 1-6. The gas-path leakage seal member
is disposed in the gap to extend partially in the first groove and
partially in the second groove with one of the raised edges
disposed entirely within the first groove and the other of the
raised edges disposed entirely within the second groove. The
gas-path leakage-gap has a higher-pressure end and a lower-pressure
end. This pressure differential seats the seal such that the raised
edges can resiliently and unattachedly contact the first and second
members respectively along the lower pressure side of the
respective first and second slots and such that the second cloth
layer assemblage can also unattachedly contact the first and second
members and along the lower pressure side of the first and second
slots. The resilient contact of the metal sheet assemblage
maintains sealing in the "plane" of the seal while allowing for
different surface shapes, assembly misalignment, vibration, and/or
thermally-induced relative movement between the first and second
members. In an embodiment of the invention, the way in which the
seal assembly is inserted with respect to the turbine members is
controlled so that the cloth layer 40 may only be provided on one
side of the seal strip, as illustrated. Specifically, the cloth is
provided on the downstream, pressure side of the junction. Thus,
the cloth layer assemblage is pushed by the differential pressure
into contact with the first and second members (as shown in FIG.
8). The cloth layer assemblage protects the metal sheet assemblage
20 against wear. The installed seal is not welded or otherwise
attached to the first and/or second members allowing for ease of
installation.
[0036] During operation of the turbine, the turbine spline seal is
vibrationally excited within a range of vibrational frequencies by
motion of generally only the first and second turbine members 52,
54. The turbine spline seal is devoid of any resonant frequency
within the range of vibrational frequencies, as is within the skill
of the artisan to design by choosing, for example, an appropriate
thickness and length of the mounting bracket 22.
[0037] The turbine assembly also includes a third turbine member
62, and the mounting bracket 22 is secured to the third turbine
member 62. In one application of the present invention, the turbine
assembly is a power-system gas turbine assembly, the first and
second turbine members 52, 54 are circumferentially-adjacent
transition pieces of the gas turbine assembly, and the third
turbine member 62 is a first stage nozzle of the gas turbine
assembly. Here, the installed turbine seal member 10 is radially
aligned, with the mounting bracket 22 located at its radially-outer
end, and a mounting block 64 is used to secure the mounting bracket
35 to the third turbine member 62. The mounting block has a bolt
hole 66 and the third turbine member has a threaded bolt hole (not
shown). A bolt 68 passes through the bolt hole in the mounting
block and threadably-engages the threaded bolt hole of the third
turbine member.
[0038] Mounting block 64 also has a first slot 70 and a second slot
72. In the illustrated embodiment, the right-angle bend 48 of the
second portion 18 engages the lower of the two slots. It is pointed
out that the first slot 70 is the lower slot in FIG. 7. It is noted
that the mounting block 64 may be rotated one half turn about bolt
66. As rotated, the second slot 72 will become the lower slot for
engagement with the right-angle bend 48 of the second portion 18 of
the turbine seal member 10.
[0039] As previously mentioned, the manually-flexible first portion
16 of the turbine seal member 10 allows all transition-piece
turbine spline seals in a standard power-system gas turbine to be
replaced in generally half a day instead of the several days
required for prior-art seals. It has been found that some prior-art
seals had a dominant resonant frequency which was excited by the
vibration (including twisting) motion of the transition pieces
leading to early seal failure. The manually-rigid second portion 18
of the turbine seal member of the turbine seal 10 has its length
and thickness chosen, as can be appreciated by those skilled in the
art, to avoid the installed turbine seal from having any resonant
frequencies which can be excited by the vibrational motion
(typically between 80 and 200 Hertz) of the transition pieces
during operation of the turbine.
[0040] 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.
* * * * *