U.S. patent application number 13/690541 was filed with the patent office on 2014-03-06 for spring-loaded seal assembly.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to Victor John Morgan, Neelesh Nandkumar Sarawate, David Wayne Weber, Christopher Edward Wolfe.
Application Number | 20140062032 13/690541 |
Document ID | / |
Family ID | 50186424 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140062032 |
Kind Code |
A1 |
Wolfe; Christopher Edward ;
et al. |
March 6, 2014 |
SPRING-LOADED SEAL ASSEMBLY
Abstract
A seal assembly is provided. The seal assembly includes a first
outer shim and a second outer shim The second outer shim is
operably coupled to the first outer shim and comprises at least one
substantially impermeable portion that spans across a gap between
at least two turbomachine components. The second outer shim further
engages the at least two turbomachine components to substantially
seal the gap. The substantially impermeable portion is
substantially planar at least along a width of the seal assembly.
The seal assembly further includes a resilient member that is
either coupled to at least a portion of an outer surface of the
first outer shim or comprises an integral portion of the first
outer shim The resilient member engages the seal assembly to
contact bottom surfaces of a cavity defined between the at least
two turbomachine components.
Inventors: |
Wolfe; Christopher Edward;
(Niskayuna, NY) ; Morgan; Victor John;
(Simpsonville, SC) ; Sarawate; Neelesh Nandkumar;
(Niskayuna, NY) ; Weber; David Wayne;
(Simpsonville, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY; |
|
|
US |
|
|
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
50186424 |
Appl. No.: |
13/690541 |
Filed: |
November 30, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13560357 |
Jul 27, 2012 |
|
|
|
13690541 |
|
|
|
|
Current U.S.
Class: |
277/590 |
Current CPC
Class: |
F16J 15/128 20130101;
F05D 2240/57 20130101; F01D 11/005 20130101 |
Class at
Publication: |
277/590 |
International
Class: |
F01D 11/00 20060101
F01D011/00 |
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH &
DEVELOPMENT
[0002] This invention was made with Government support under
contract number DE-FC26-05NT42643, awarded by the Department Of
Energy. The Government has certain rights in the invention.
Claims
1. A seal assembly comprising: a first outer shim; a second outer
shim operably coupled to the first outer shim, wherein the second
outer shim comprises at least one substantially impermeable portion
configured to span across a gap between at least two turbomachine
components and further configured to engage the at least two
turbomachine components to substantially seal the gap, wherein the
substantially impermeable portion is substantially planar at least
along a width of the seal assembly; and a resilient member coupled
to at least a portion of an outer surface of the first outer shim
or comprising an integral portion of the first outer shim, wherein
the resilient member is configured to engage the seal assembly to
contact bottom surfaces of a cavity defined between the at least
two turbomachine components.
2. The seal assembly of claim 1, wherein the resilient member
comprises: a substantially planar portion configured to extend at
least along the portion of the width of the seal assembly; a first
arm portion including a first end and a second end; and a second
arm portion including a first end and a second end, wherein the
first end of the first arm portion and the first end of the second
arm portion are operably coupled to opposing ends of the
substantially planar portion of the resilient member.
3. The seal assembly of claim 2, wherein the second end of the
first arm portion and the second end of the second arm portion are
operably coupled to top surfaces of the cavity defined between the
at least two turbomachine components.
4. The seal assembly of claim 1, further comprising at least one
inner layer disposed between the first outer shim and the second
outer shim.
5. The seal assembly of claim 4, wherein the at least one inner
layer comprises at least one of a wire mesh woven cloth, a flat
ribbon mesh woven cloth, a honeycomb structure, a corrugated shim,
or a compliant shim.
6. The seal assembly of claim 1, further comprising a first
extension and a second extension, operably coupled to opposing end
portions of the first outer shim and configured to extend at least
along a first portion of a thickness of the seal assembly.
7. The seal assembly of claim 1, further comprising a third
extension and a fourth extension, operably coupled to opposing end
portions of the second outer shim and configured to extend at least
along a second portion of a thickness of the seal assembly.
8. The seal assembly of claim 1, wherein the second outer shim, the
resilient member, and the first outer shim are operably coupled by
one of a weld or a braze positioned in a medial portion of the
width of the seal assembly, the weld or the braze configured to
extend along a thickness of the seal assembly.
9. The seal assembly of claim 1, further comprising an adhesive or
a fastener for operably coupling the second outer shim, the
resilient member, and the first outer shim.
10. The seal assembly of claim 1, wherein the seal assembly is
configured to be disposed in the cavity defined between the at
least two turbomachine components, wherein the cavity includes a
thickness less than a thickness of the seal assembly.
11. The seal assembly of claim 1, wherein the resilient member
includes a creep resistant nickel based alloy.
12. The seal assembly of claim 1, wherein at least the first outer
shim and the resilient member comprise an integral element.
13. A turbomachine comprising: at least two turbomachine
components; a seal assembly disposed in a cavity defined between
the at least two turbomachine components, wherein the seal assembly
comprises: a first outer shim; a second outer shim operably coupled
to the first outer shim, wherein the second outer shim comprises at
least one substantially impermeable portion configured to span
across a gap between the at least two turbomachine components, and
further configured to engage the at least two turbomachine
components to substantially seal the gap, wherein the substantially
impermeable portion is substantially planar at least along a width
of the seal assembly; and a resilient member coupled to at least a
portion of an outer surface of the first outer shim or comprising
an integral portion of the first outer shim, wherein the resilient
member is configured to engage the seal assembly to contact bottom
surfaces of the cavity defined between the at least two
turbomachine components.
14. The turbomachine of claim 13, wherein the resilient member
comprises: a substantially planar portion configured to extend at
least along a portion of the width of the seal assembly; a first
arm portion including a first end and a second end; and a second
arm portion including a first end and a second end, wherein the
first end of the first arm portion and the first end of the second
arm portion are operably coupled to opposing ends of the
substantially planar portion of the resilient member.
15. The turbomachine of claim 14, wherein the second end of the
first arm portion and the second end of the second arm portion are
operably coupled to top surfaces of the cavity defined between the
at least two turbomachine components.
16. The turbomachine of claim 13, wherein the seal assembly further
comprises at least one inner layer disposed between the first outer
shim and the second outer shim.
17. The turbomachine of claim 13, wherein the seal assembly further
comprises a first extension and a second extension, operably
coupled to opposing end portions of the first outer shim and
configured to extend at least along a first portion of a thickness
of the seal assembly.
18. The turbomachine of claim 13, wherein the seal assembly further
comprises a third extension and a fourth extension, operably
coupled to opposing end portions of the second outer shim and
configured to extend at least along a second portion of a thickness
of the seal assembly.
19. A seal assembly comprising: an outer shim comprising at least
one substantially impermeable portion configured to span across a
gap between at least two turbomachine components and further
configured to engage the at least two turbomachine components to
substantially seal the gap, wherein the substantially impermeable
portion is substantially planar at least along a width of the seal
assembly; and a resilient member configured to engage the seal
assembly to contact bottom surfaces of a cavity defined between the
at least two turbomachine components.
20. The seal assembly of claim 19, wherein the seal assembly
further comprises at least one inner layer disposed between the
outer shim and the resilient member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application No. 13/560,357, entitled "Layered Seal For
Turbomachinery," filed on Jul. 27, 2012, the entire contents of
which are hereby incorporated by reference.
BACKGROUND
[0003] The invention relates generally to a seal assembly and, more
particularly, to seal assemblies for reducing or substantially
eliminating leakage in a turbomachine such as a heavy-duty gas
turbine or an aero-derivative gas turbine.
[0004] A turbomachine has a gas path, which typically includes, in
serial-flow relationship, an air intake (or inlet), a compressor, a
combustor, a turbine area, and a gas outlet (or exhaust nozzle).
Leakage of high pressure cooling flows between adjacent stator
components in the turbomachine such as shrouds, nozzles, and
diaphragms into a low pressure hot gas path may lead to reduced
efficiency and may require an increase in burn temperature, and
thereby an increase in NO.sub.x. Turbine efficiency may thus be
improved by reducing or eliminating leakage locations.
[0005] Preventing leakage between adjacent stator components with
seals may be challenging due to the fact that the seals must be
durable enough to withstand several thousand hours of operation and
flexible enough to compensate for assembly misalignment, different
engaging surfaces, vibration during operation, and unequal thermal
expansion between adjacent stator components.
[0006] Thus, there is a need to provide a seal assembly to reduce
or substantially eliminate leakages between adjacent stator
components. It is further desirable that such seals are durable
enough to withstand several thousand hours of operation and
flexible enough to compensate for assembly misalignment, different
engaging surfaces, vibration during operation, and unequal thermal
expansion between adjacent stator components.
BRIEF DESCRIPTION
[0007] The inventors of the present application have identified
that a through leakage occurs through a gap left under a central
metallic shim that does not extend to the bottom of the seal and an
end-face leakage occurs through a gap between the ends of the cloth
seal and the ends of a mating slot or cavity defined between
adjacent stator components in conventional cloth seal embodiments.
The use of the combination of a biasing resilient member on the top
of a seal assembly and an impermeable outer shim on the bottom of
the seal assembly is expected to reduce leakages.
[0008] In accordance with one embodiment, a seal assembly is
provided. The seal assembly includes a first outer shim and a
second outer shim The second outer shim is operably coupled to the
first outer shim and comprises at least one substantially
impermeable portion configured to span across a gap between at
least two turbomachine components. The second outer shim is further
configured to engage the at least two turbomachine components to
substantially seal the gap. The substantially impermeable portion
is substantially planar at least along a width of the seal
assembly. The seal assembly further includes a resilient member
that is either coupled to at least a portion of an outer surface of
the first outer shim or comprises an integral portion of the first
outer shim The resilient member is configured to engage the seal
assembly to contact bottom surfaces of a cavity defined between the
at least two turbomachine components. The resilient member may
include a spring that may be configured to push the seal assembly
downwards so that the second outer shim maintains a desired contact
with the bottom surfaces of the cavity.
[0009] In another embodiment a seal assembly is provided. The seal
assembly includes an outer shim comprising at least one
substantially impermeable portion configured to span across a gap
between at least two turbomachine components. The outer shim is
further configured to engage the at least two turbomachine
components to substantially seal the gap. The substantially
impermeable portion is substantially planar at least along a width
of the seal assembly. The seal assembly further includes a
resilient member that is configured to engage the seal assembly to
contact bottom surfaces of a cavity defined between the at least
two turbomachine components.
[0010] In yet another embodiment a turbomachine is provided. The
turbomachine includes at least two turbomachine components and a
seal assembly disposed in a cavity defined between the at least two
turbomachine components. The seal assembly includes a first outer
shim and a second outer shim The second outer shim is operably
coupled to the first outer shim and comprises at least one
substantially impermeable portion configured to span across a gap
between the at least two turbomachine components. The second outer
shim is further configured to engage the at least two turbomachine
components to substantially seal the gap. The substantially
impermeable portion is substantially planar at least along a width
of the seal assembly. The seal assembly further includes a
resilient member that is either coupled to at least a portion of an
outer surface of the first outer shim or comprises an integral
portion of the first outer shim The resilient member is configured
to engage the seal assembly to contact bottom surfaces of a cavity
defined between the at least two turbomachine components.
DRAWINGS
[0011] These and other features, aspects, and advantages of the
present invention will become better understood when the following
detailed description is read with reference to the accompanying
drawings in which like characters represent like parts throughout
the drawings, wherein:
[0012] FIG. 1 is a cross-section of a portion of a turbomachine
including a first turbomachine component, a second turbomachine
component, and a seal assembly comprising a resilient member and
first and second outer shims in accordance with one embodiment.
[0013] FIG. 2 is a seal assembly in accordance with another
embodiment wherein one or more inner layers are present between the
first and second outer shims.
[0014] FIG. 3 is a seal assembly in accordance with another
embodiment, wherein the resilient member and the first outer shim
are integral.
[0015] FIG. 4 is a seal assembly illustrating perpendicular
extensions of the first and second outer shims, in accordance with
one embodiment.
[0016] FIG. 5 is a seal assembly illustrating angled extensions of
the first and second outer shims, in accordance with one
embodiment.
[0017] FIG. 6 is a seal assembly illustrating perpendicular and
angled extensions of the first and second outer shims, in
accordance with one embodiment.
[0018] FIG. 7 is a seal assembly including extensions of the first
outer shim beyond a horizontal axis, in accordance with one
embodiment.
[0019] FIG. 8 is a seal assembly including the extensions of the
first outer shim to the horizontal axis, in accordance with one
embodiment.
[0020] FIG. 9 is a seal assembly including a curved "shepherds
hook" first outer shim, in accordance with one embodiment.
[0021] FIG. 10 is a seal assembly including the curved "shepherds
hook" first outer shim, in accordance with another embodiment.
[0022] FIG. 11 is a seal assembly where the extensions of the first
outer shim are joined to extensions of the second outer shim, in
accordance with one embodiment.
[0023] FIG. 12 is a seal assembly in accordance with another
embodiment which includes a single outer shim
DETAILED DESCRIPTION
[0024] Unless defined otherwise, technical and scientific terms
used herein have the same meaning as is commonly understood by one
of ordinary skill in the art to which this disclosure belongs. The
terms "first", "second", and the like, as used herein do not denote
any order, quantity, or importance, but rather are used to
distinguish one element from another. Also, the terms "a" and "an"
do not denote a limitation of quantity, but rather denote the
presence of at least one of the referenced items. The term "or" is
meant to be inclusive and mean one, some, or all of the listed
items. The use of terms such as "including," "comprising," or
"having" and variations thereof herein are meant to encompass the
items listed thereafter and equivalents thereof as well as
additional items. The terms "top," "bottom," "side," "middle,"
"outer" and "interior" as used herein are meant to reflect
relative, as opposed to absolute positions.
[0025] Also, the term "substantial" or "substantially" as used
herein is a qualifier term to indicate that the characteristic is
present but some deviation is allowed. The amount of allowable
deviation can vary depending on the particular context. For
example, "substantially planar" indicates a surface or plane is
close to being exactly planar, but small deviations are included,
for example, either an overall or local deviation of two to five
degrees. The term "substantially impermeable" indicates a material
that is either completely impervious to movement of any material or
composition, or combination of materials or compositions, or
reduces leakage to an acceptable limit (for example, in one
embodiment, the leakage rate is reduced to half of the leakage rate
in existing seals). Also, the term "substantially seal" indicates
that the seal is firmly contacted with a surface or plane such that
the possibility of leakage is eliminated (that is, leakage is nil)
or is reduced to an acceptable limit. Components, aspects,
features, configurations, arrangements, uses and the like
described, illustrated or otherwise disclosed herein with respect
to any particular seal embodiment may similarly be applied to any
other seal embodiment disclosed herein.
[0026] Various embodiments of the present invention describe seal
assemblies that may be configured for, or used with, any number or
type of turbomachine components requiring a seal to reduce or
substantially eliminate leakage between the turbomachine
components.
[0027] FIG. 1 is a cross-section of a portion of a turbomachine 100
including a first turbomachine component 102 and a second
turbomachine component 104, in accordance with one embodiment. In
some embodiments, the first and second turbomachine components 102
and 104 may be two adjacent stator components such as, but not
limited to, shrouds, nozzles, or diaphragms. In some embodiments,
as shown in FIG. 1, the first and second turbomachine components
102 and 104 may be spaced apart so as to define a gap or gas
leakage path 106 therebetween. The gap 106 may allow flow, such as
airflow, between the first and second components 102 and 104. In
some configurations, the first and second components 102 and 104
may be positioned between a first airflow 108, such as cooling
airflow, and a second airflow 110, such as hot combustion airflow.
The term "airflow" as used herein refers to the movement of any
material or composition, or combination of materials or
compositions, translating through the gap 106 between the first and
second components 102 and 104.
[0028] As shown in FIG. 1, in some embodiments, the first
turbomachine component 102 has a first recess 112 comprising a top
surface 114 and a bottom surface 116. Similarly, as shown in FIG.
1, the second turbomachine component 104 has a second recess 118
comprising a top surface 120 and a bottom surface 122. In various
embodiments, the first and second recesses 112 and 118 may be
substantially aligned with each other for receiving a seal assembly
124 to reduce or substantially eliminate leakage between the first
and second turbomachine components 102 and 104. In order to provide
the alignment, the bottom surfaces 116 and 122 of the first and
second recesses 112 and 118, respectively, may lie on a common
plane and the top surfaces 114 and 120 of the first and second
recesses 112 and 118, respectively, may lie on another common plane
to provide even surfaces at the bottom and top surfaces of the
first and second recesses 112 and 118. However, the first and
second recesses 112 and 118 may have any size, shape, or
configuration capable of accepting a seal therein. The area between
the first and second recesses 112 and 118 defines a slot or a
cavity that extends from within the first turbomachine component
102, across the gap 106, and into the second turbomachine component
104. In some embodiments, the seal assembly 124 may be disposed
between the first and second turbomachine components 102 and 104
such that the seal assembly 124 may contact bottom surfaces of the
cavity, which may be same as the bottom surfaces 116 and 122 of the
first and second recesses 112 and 118, respectively. As shown in
FIG. 1, in some embodiments, the seal assembly 124 may span across
the gap 106 and engage the first and second turbomachine components
102 and 104 to thereby seal the gap 106. Also, as shown in FIG. 1,
in some embodiments, the seal assembly 124 may not completely cover
the bottom surfaces 116 and 122 but is in contact with substantial
portion of the bottom surfaces 116 and 122. In some other
embodiments, the seal assembly 124 may completely cover the bottom
surfaces 116 and 122.
[0029] In some embodiments (not shown), due to manufacturing and
assembly limitations or variations, as well as thermal expansion,
movement and the like during operation, the first and second
recesses 112 and 118 may be skewed, twisted, angled, or otherwise
misaligned. In such embodiments, the seal assembly used may be
flexible enough to account for such misalignment. For example,
above referenced U.S. patent application No. 13/560,357 describes
flexible seals to account for such misalignments.
[0030] As illustrated in FIG. 1, in some embodiments, the seal
assembly 124 may include a first outer shim 126 and a second outer
shim 128. The second outer shim 128 may be operably coupled to the
first outer shim 126. The first outer shim 126 may include a first
end portion 130, a second end portion 132, and a substantially
impermeable intermediate portion 134 connecting the first and
second end portions 130 and 132. As shown in FIG. 1, the
intermediate portion 134 may be substantially planar (hereinafter
referred to as "planar portion 134") at least along a width "W1" of
the seal assembly 124, in accordance with various embodiments of
the invention. The second outer shim 128 may include a first end
portion 136, a second end portion 138, and a substantially
impermeable and planar portion 140 (hereinafter referred to as
"planar portion 140") configured to couple the first and second end
portions 136 and 138 and further configured to extend at least
along the width "W1" of the seal assembly 124. Further, in some
embodiments, the width "W1" of the seal assembly 124 may be less
than a width "W2" of the cavity defined by the first and second
recesses 112 and 118. In some embodiments, in addition to being
impermeable to prevent the passage of airflow through the seal
assembly 124, the first and second outer shims 126 and 128 may be
resistant, or at least tolerant, to high temperatures being
produced within the turbomachine 100. In an exemplary embodiment,
the first and second outer shims 126 and 128 may include a metal
such as a cobalt-based alloy, for example, but not limited to,
Haynes.RTM. 188 or Haynes.RTM. 25 (L605). In one embodiment, the
thickness of each of the first and second outer shims 126 and 128
may be about 10 mils to about 100 mils In another embodiment, the
thickness of the first and second outer shims 126 and 128 may range
between about 10 mils to about 30 mils.
[0031] As shown in FIG. 1, in some embodiments, the planar portion
140 may be configured to span across the gap 106 between the first
and second turbomachine components 102 and 104 and further
configured to engage the turbomachine components 102 and 104 to
substantially seal the gap 106. The sealing of the gap 106 achieved
by the second outer shim 128 may be more efficient than the
existing cloth seals when the material used to manufacture the
second outer shim 128 is substantially impermeable. The leakage
rate is reduced due to the portion 140 being substantially
impermeable and planar. The planar aspect facilitates the portion
140 to be completely or substantially engaged with the bottom
surfaces 116 and 122 of the first and second recesses 112 and
118.
[0032] As shown in FIG. 1, the seal assembly 124 further includes a
resilient member 142, such as for example, a spring. In some
embodiments, the resilient member 142 may be configured to engage
the seal assembly 124 to contact the bottom surfaces 116 and 122 of
the first and second recesses 112 and 118, respectively. In an
exemplary embodiment, when the pressure difference across the seal
assembly 124 may not be sufficient by itself to engage the seal
assembly 124 into contact with the bottom surfaces 116 and 122, the
resilient member 142 may be configured to constantly push the seal
assembly 124 downwards so that the second outer shim 128 maintains
a desired contact with the bottom surfaces 116 and 122. In one
embodiment, the desired contact indicates that a substantial
portion of a bottom surface (not shown) of the planar portion 140
of the second outer shim 128 is in contact with the bottom surfaces
116 and 122 such that the seal assembly 124 may substantially seal
the gap 106. In another embodiment, the desired contact indicates
that the entire bottom surface of the planar portion 140 is in
contact with the bottom surfaces 116 and 122. In some embodiments,
constant pressure by the resilient member to push the substantially
impermeable shim 128 to achieve the desired contact, and thus
substantially seal the gap 106, may result in reducing or
substantially eliminating through (shown in FIG. 1) and end-face
leakages between the two adjacent stator components.
[0033] Referring still to FIG. 1, the resilient member 142 may
include a substantially planar portion 143. The substantially
planar portion 143 may be configured to extend at least along a
portion of the width "W1" of the seal assembly 124, in accordance
with some embodiments. The term "at least along a portion" as used
herein refers to extension along a small part of, a major part of,
entire, or beyond, for example, width "W1" of the seal assembly
124. As illustrated in FIG. 1, in some embodiments, the resilient
member 142 may further include a first arm portion 144 including a
first end 146 and a second end 148, and a second arm portion 150
including a first end 152 and a second end 154. The first end 146
of the first arm portion 144 and the first end 152 of the second
arm portion 150 may be operably coupled to opposing ends 156 and
158, respectively, of the substantially planar portion 143 of the
resilient member 142, in accordance with one embodiment. Also, as
shown in FIG. 1, in some embodiments, the second end 148 of the
first arm portion 144 may be operably coupled to a portion of the
top surface 114 of first recess 112, and the second end 154 of the
second arm portion 150 may be operably coupled to a portion of the
top surface 120 of the second recess 118. As used herein, "operably
coupled" refers to a second end (148 or 154) of an arm portion (144
or 150) of the resilient member 142 being configured to contact
with a top surface (114 or 120) of a recess (112 or 118) during
operation. The resilient member may have any shape, size,
configuration, or composition without deviating from the scope of
the invention. For example, commonly assigned U.S. Patent
Publication No. 2009/0085305 discloses different shapes, sizes,
configurations, or compositions of springs, and is herein
incorporated by reference in its entirety. One such embodiment is
illustrated in FIG. 2, where the resilient member may comprise a
leaf spring such that the planar portion 143, the first arm portion
144 and the second arm portion 150 may be formed from an integral
bent sheet.
[0034] Referring again to FIG. 1, in one embodiment, the resilient
member 142 may be coupled to at least a portion of an outer surface
160 of the first outer shim 126. The term "at least a portion" as
used herein refers to a small part of, a major part of, entire, or
extension beyond, for example, the outer surface 160 of the first
outer shim 126. In another embodiment, the resilient member 142 may
be integrated with the first outer shim 126 such that the resilient
member 142 may comprise an integral portion of the first outer shim
126.
[0035] In one exemplary embodiment, the resilient member 142 may
include, but is not limited to, spring steel or other
wear-resistant material capable of withstanding the environment of
the turbomachine 100, which the seal assembly 124 may experience.
In another exemplary embodiment, the resilient member 142 may
include a high-temperature creep resistant material selected from,
for example, an austenitic nickel-chromium alloy such as Inconel
X-750.TM., a nickel based alloy such as Rene-41.TM., or the like.
The material of the resilient member 142 may be selected such that
it provides flexibility to the resilient member 142 to bend,
stretch or compress (and thus may have high tensile strength) to
various shapes and sizes. In some embodiments, the resilient member
142 may have a thickness of about 3 mils to about 50 mils.
[0036] In some embodiments, a thickness of the seal assembly 124
before being disposed in the cavity may be greater than a thickness
"T" of the cavity defined by the first and second recesses 112 and
118. In such embodiments, the thickness of the seal assembly 124
may be reduced during installation in the cavity to a thickness,
which may be equal to the thickness T of the cavity, so as to
accommodate the seal assembly 124 within the cavity. In such
embodiments, the seal assembly 124 may be compressed to fit within
the cavity, and thereby may include portions or components
configured for such compression. In some embodiments, the
compression may be achieved due to flexibility of the resilient
member 142, which may be bent, stretched or compressed to any shape
or size. For example, U.S. Patent Publication No. 2009/0085305 and
U.S. patent application No. 13/306,090 are directed to seals with
such "compression fit" features. U.S. patent application No.
13/306,090 is herein incorporated by reference in its entirety.
[0037] The first outer shim 126 and the second outer shim 128 may
be operably coupled to one another using any known fastening means.
In one exemplary embodiment, a weld or a braze may be positioned in
a medial portion 162 of the width "W1" of the seal assembly 124. In
such embodiments, the weld or braze may be configured to extend
along the thickness of the seal assembly 124. Alternatively, in
some other embodiments, other types of known fastening means such
as an adhesive or a fastener may be used. In embodiments wherein
the resilient member 142 and the first outer shim 126 are discrete
components, the first outer shim 126, the second outer shim 128,
and the resilient member 142 may be similarly operably coupled by
any known fastening means, such as, but not limited to, weld,
braze, adhesive, or fastener, or any combination thereof. U.S.
Patent Publication No. 2009/0085305 and U.S. patent application No.
13/560,357 describe the use of various fastening means to couple
various components of a seal assembly.
[0038] In various embodiments, the shapes and configurations of the
first outer shim, the second outer shim, or the resilient member
may vary. Moreover, in some embodiments, the seal assembly may
include additional layers. Examples of such variations are provided
in FIGS. 2-12.
[0039] FIG. 2 is a seal assembly 200 including a first inner layer
202 and a second inner layer 204 disposed between the first and
second outer shims 126 and 128. In an exemplary embodiment, the
inner layers 202, 204 may include a wire mesh woven cloth, a flat
ribbon mesh woven cloth, a honeycomb structure, a corrugated shim,
or a compliant shim, or any combination thereof. In one embodiment
where the inner layers 202 and 204 are shims, the shape, size and
configuration of the shims 202 and 204 may or may not be the same
as that of the first and second outer shims 126 and 128. Although
the seal assembly 200 depicts the first and second inner layers 202
and 204, the seal assembly 200 may include any number or type of
inner layers. The first and second inner layers 202 and 204 may be
any material, shape, size and configuration. In some embodiments,
the first and second inner layers 202 and 204 may be more porous or
flexible as compared to other components (such as the first and
second outer shims 126 and 128) of the seal assembly 200. U.S.
patent application No. 13/560,357 describes various shapes, sizes
and configurations of exemplary shims and inner layers.
[0040] The seal assembly 200 of FIG. 2 includes a leaf spring 206
with a different shape than the resilient member 142 of FIG. 1. In
some embodiments, the leaf spring 206 may include the planar
portion 143, the first arm portion 144 and the second arm portion
150 that may be formed from an integral bent sheet. Various
embodiments described above for the seal assembly 124 may be
equally applied to the seal assembly 200. In one embodiment, the
leaf spring 206 in FIG. 2 may be replaced with the resilient member
142 of FIG. 1. The fastening means described above with reference
to FIG. 1 may be used to couple the inner layers 202 and 204 to the
rest of the seal assembly 200.
[0041] The shapes of the first outer shim 126 or the second outer
shim 128 or both may vary. FIGS. 3-12 depict different exemplary
shapes of the outer shim 126, 128.
[0042] As shown in FIGS. 4-10, in some embodiments, the first outer
shim 126 may additionally include a first extension 302 and a
second extension 304 that may be operably coupled to the opposing
first and second end portions 130 and 132, respectively, of the
first outer shim 126. In some embodiments, the first and second
extensions 302 and 304 may be configured to extend at least along a
first portion (not shown) of the thickness of the seal assembly.
The thickness or height of the first portion along which the first
and second extensions 302 and 304 extend may vary across different
embodiments, as shown in FIGS. 4-10.
[0043] As shown in FIGS. 3-6 and FIG. 12, in some embodiments, the
second outer shim 128 may additionally include a third extension
306 and a fourth extension 308 that may be operably coupled to the
opposing end portions 136 and 138, respectively, of the second
outer shim 128. In some embodiments, the third and fourth
extensions 306 and 308 may be configured to extend at least along a
second portion (not shown) of the thickness of the seal assembly.
The thickness or height of the second portion along which the third
and fourth extensions 306 and 308 extend may vary across different
embodiments, as shown in FIGS. 3-6 and FIG. 12. As used herein for
the extensions 302, 304, 306, and 308, "operably coupled" refers to
the extensions being either curved or bent integral to the
respective outer shim or shims 126, 128, or separate elements that
are physically attached to the respective outer shim or shims 126,
128. Similar to the planar portions 134 and 140, in various
embodiments of the invention, the extensions 302, 304, 306, and 308
may also be substantially impermeable.
[0044] Due to the addition of the extensions 302, 304, 306 and 308
in the first and second outer shims 126 and 128, increased
stiffness may be provided to the overall structure of the seal
assembly. Moreover, due to the extensions 302, 304, 306 and 308,
any possibility of unwanted material at the edges of the planar
portions 134 and 140, for example, because of sharp edges of the
planar portions 134 and 140 is avoided.
[0045] Referring to FIG. 3, this figure illustrates that in some
embodiments, the resilient member 142 in the seal assembly 300 is
an integral portion of the first outer shim 126. Additionally, the
seal assembly 300 includes the third and fourth extensions 306 and
308 oriented substantially perpendicular to the planar portion 140
of the second outer shim 128.
[0046] FIG. 12 is a seal assembly 1200 in accordance with another
embodiment wherein no first outer shim 126 is present. In this
embodiment, the resilient member 142 and the second outer shim 128
are either coupled or integrated. In such embodiments, the second
outer shim 128 may be interchangeably referred to as outer shim
128. As shown in FIG. 12, in some embodiments, the resilient member
142 in the seal assembly 300 may be operably coupled indirectly to
at least a portion (not shown) of an inner surface 1202 of the
outer shim 128, that is, via the optional first and second inner
layers 202 and 204, which may be disposed between the outer shim
128 and the resilient member 142. Alternatively, in some other
embodiments (not shown) where the first and second inner layers 202
and 204 are not present, the resilient member 142 may be either
directly coupled to at least the portion of the inner surface 1202
of the outer shim 128 or an integral portion of the outer shim 128.
In an exemplary embodiment, the resilient member 142 may be coupled
(directly or indirectly) to some or entire top surface 1204 (which
may be, for example, equivalent to a planar part of the inner
surface 1202) of the planar portion 140 of the outer shim 128.
Irrespective of whether the coupling is direct or indirect, the
coupling between different components may be achieved using any
known fastening means as described above.
[0047] Various embodiments described above for the seal assemblies
100, 200, and 1200 may be equally applied to the seal assembly 300
and seal assemblies of FIGS. 4-11. In one exemplary embodiment, the
shape and configuration of the outer shim 128 or the resilient
member 142 or both shown in FIGS. 3 and 12 may be replaced with the
type shown in the seal assembly 100, 200. In another exemplary
embodiment, the shape and configuration of the outer shim 128 shown
in FIGS. 3 and 12 may be replaced with the type shown in any of
FIGS. 4-11.
[0048] Referring to FIG. 4, in some other embodiments, the
resilient member 142 in the seal assembly 400 is shown as being
discrete from the first outer shim 126. As shown in FIG. 4, in some
embodiments, the seal assembly 400 may include the first and second
extensions 302 and 304 oriented substantially perpendicular to the
planar portion 134 (shown in FIG. 4) of the first outer shim 126,
in addition to the third and fourth extensions 306 and 308 oriented
substantially perpendicular to the planar portion 140 of the second
outer shim 128. Gaps 402 and 404 are provided between adjacent
pairs of the extensions 302, 306 and 304, 308 to allow for
flexibility and tolerance changes during seal compression.
[0049] Referring to FIG. 5, in some embodiments, a seal assembly
500 is depicted where the first and second extensions 302 and 304
of the first outer shim 126, and the third and fourth extensions
306 and 308 of the second outer shim 128 may be angled from the
planar portions of the first and second outer shims 126 and 128
instead of being oriented in a substantially perpendicular
manner.
[0050] Referring to FIG. 6, in some other embodiments, a seal
assembly 600 is depicted where the first and fourth extensions 302
and 308 may be angled from the planar portions 134 and 140,
respectively, and the second and third extensions 304 and 306 may
be oriented substantially perpendicular to the planar portions 134
and 140, respectively. As shown in FIG. 6, the first extension 302
may extend to a horizontal axis X-X' defined along the width of the
bottom surface 116 of the first recess 112 (see FIG. 1) such that a
bottom surface 602 of the first extension 302 may lie on the same
plane as defined by the bottom surface 116.
[0051] Alternatively, in another embodiment (not shown), instead of
the fourth extension 308, the second extension 304 may be angled
from the planar portion 134 such that a bottom surface of the
second extension 304 may extend to the horizontal axis X-X' such
that the bottom surface of the second extension 304 may lie on the
same plane as defined by the bottom surface 122 of the second
recess 118.
[0052] Referring to FIG. 7, a seal assembly 700 is depicted where
the first and second extensions 302 and 304 of the first outer shim
126 may extend slightly beyond the horizontal axis X-X' defined
along the width of the bottom surfaces 116 and 122 (not shown in
FIG. 7) of the cavity such that a plane defined by the bottom
surface 602 and a bottom surface 702 of the first and second
extensions 302 and 304, respectively, may be slightly below a plane
defined by the bottom surfaces 116 and 122. The extension slightly
beyond the horizontal axis X-X' may facilitate in providing
additional resistance to any through leakage that may occur in
embodiments where the extension is only to the horizontal axis
X-X', in accordance with various embodiments. A thickness "T1" of a
portion of the first extension 302 and a thickness "T2" of a
portion of the second extension 304 defined between the bottom
surfaces 116 and 122 of the cavity and the bottom surfaces 602 and
702 of the first and second extensions 302 and 304, respectively,
may be small. Small thicknesses T1 and T2 may allow the planar
portion 140 of the second outer shim 128 to be still completely or
substantially engaged with the bottom surfaces 116 and 122 of the
cavity. In some embodiments, the thicknesses T1 and T2 may be
different or same.
[0053] As illustrated in FIG. 8, in some embodiments, a seal
assembly 800 is depicted where the first and second extensions 302
and 304 of the first outer shim 126 may extend to the horizontal
axis X-X', such that the bottom surfaces 602 and 702 of the second
extensions 302 and 304, respectively, are on the same plane as the
bottom surfaces 116 and 122 of the cavity (See FIG. 1).
[0054] Referring to FIG. 9, a seal assembly 900 is depicted where
the shape of the first outer shim 126 is a curved "shepherds hook",
in accordance with one embodiment. As shown in FIG. 9, in some
embodiments, the first and second extensions 302 and 304 of the
first outer shim 126 may be curved portions that may extend beyond
the horizontal axis X-X' such that a plane defined by the bottom
surfaces 602 and 702 of the first and second extensions 302 and
304, respectively, may be below the plane defined by the bottom
surfaces 116 and 122 (not shown in FIG. 9) of the cavity. Similar
to the seal assembly 700 depicted in FIG. 7, the thicknesses T1 and
T2 may be small enough to allow the planar portion 140 of the
second outer shim 128 to still completely or substantially engage
with the bottom surfaces 116 and 122 of the cavity.
[0055] FIG. 10 depicts a seal assembly 1000 where the shape of the
first outer shim 126 is the curved "shepherds hook", in accordance
with another embodiment. As shown in FIG. 10, in some embodiments,
the first and second extensions 302 and 304 of the first outer shim
126 may be curved portions that may extend to the horizontal axis
X-X', such that the bottom surfaces 602 and 702 of the first and
second extensions 302 and 304, respectively, are on the same plane
as the bottom surfaces 116 and 122 (not shown in FIG. 10) of the
cavity.
[0056] As described above, the extension of the first and second
extensions 302 and 304 to or slightly beyond the bottom surfaces
116 and 122 of the cavity may be helpful to provide additional
resistance to the through leakage. Irrespectively, in some
embodiments, the end-face and through leakages may be eliminated or
substantially reduced using the planar portion 140 of the second
outer shim 128 without the first, second, third, and/or fourth
extensions 302, 304, 306, 308.
[0057] Referring to FIG. 11, a seal assembly 1100 is depicted that
is similar to the seal assembly 400 depicted in FIG. 4, except that
the first and third extensions 302 and 306 are joined to close a
gap 402 therebetween, and the second and fourth extensions 304 and
308 are joined to close another gap 404 therebetween. The seal
assembly 1100 may result in a structure that is much stiffer than
that provided when there are no extensions. Moreover, due to the
closed enclosure, collection of unwanted material at the edges of
the planar portions is avoided.
[0058] The seal assemblies disclosed in accordance with various
embodiments of the invention may reduce the leakage between
adjacent turbomachine components so as to improve overall system
performance and efficiency. Various embodiments of the invention
describe the use of the combination of a biasing resilient member
(such as 142 or 206) on the top of a seal assembly (such as 124,
200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, or 1200) and an
impermeable outer shim (such as the second outer shim 128) on the
bottom of the seal assembly to reduce leakages. A planar portion
(such as 140) of the impermeable outer shim may engage with bottom
surfaces of a cavity that extends between a first turbomachine
component (such as 102) and a second turbomachine component (such
as 104) to eliminate or substantially reduce the through and
end-face leakages. The impermeable outer shim on the bottom of the
seal assembly may also result in reducing other types of leakages
such as around leakage that may otherwise occur around the seal
assembly. In some exemplary embodiments, the cooling airflow may
enter in the area between the impermeable outer shims on top and
bottom of the seal assembly; however, the cooling airflow will be
blocked by the planar portion (such as 140) of the impermeable
outer shim on the bottom from merging with the hot combustion
airflow, thereby preventing around leakage.
[0059] Moreover, some extensions (302, 304, or any combination
thereof) of the impermeable outer shim, for example, to or slightly
beyond the bottom surfaces (such as 116 and 122) of the cavity may
be helpful to provide additional resistance to the through leakage.
Overall leakage rate through the seal assemblies of various
embodiments of the invention may be reduced by, for example, thirty
percent or more than that achieved using the existing cloth seals.
Specifically, various embodiments of the invention may reduce or
substantially eliminate end-face and through leakages between
adjacent turbomachine components.
[0060] Seal assemblies as described in accordance with various
embodiments are durable enough to withstand several thousand hours
of operation and flexible enough to compensate for assembly
misalignment, different engaging surfaces, vibration during
operation, and unequal thermal expansion between adjacent stator
components. In some embodiments, the resilient member or "spring"
may be resilient enough to accommodate vibrations during
operation.
[0061] While the dimensions and types of materials described herein
define the parameters of various embodiments, they are by no means
limiting and are merely exemplary. It is to be understood that a
skilled artisan will recognize the interchangeability of various
features from different embodiments and that the various features
described, as well as other known equivalents for each feature, may
be mixed and matched by one of ordinary skill in this art to
construct additional systems and techniques in accordance with
principles of this disclosure. It is, therefore, to be understood
that the appended claims are intended to cover all such
modifications and changes as fall within the true spirit of the
invention.
[0062] While only certain features of the invention have been
illustrated and described herein, many modifications and changes
will occur to those skilled in the art. It is, therefore, to be
understood that the appended claims are intended to cover all such
modifications and changes as fall within the true spirit of the
invention.
* * * * *