U.S. patent application number 13/019018 was filed with the patent office on 2012-08-02 for stiffening system for steam turbine casing.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Rajendra Gonoor, Erik Eduardo Lopez Partida, Daniel Ross Predmore, Robert James Sherwood.
Application Number | 20120195752 13/019018 |
Document ID | / |
Family ID | 46511587 |
Filed Date | 2012-08-02 |
United States Patent
Application |
20120195752 |
Kind Code |
A1 |
Lopez Partida; Erik Eduardo ;
et al. |
August 2, 2012 |
STIFFENING SYSTEM FOR STEAM TURBINE CASING
Abstract
A steam turbine casing stiffening system is disclosed. In one
embodiment, a steam turbine inner casing stiffening system is
disclosed, including: an inner casing segment; and a stiffening
member affixed to and extending radially outward from an external
surface of the inner casing segment, the stiffening member
configured to support at least a portion of the inner casing
segment.
Inventors: |
Lopez Partida; Erik Eduardo;
(Clifton Park, NY) ; Gonoor; Rajendra; (Bangalore,
IN) ; Predmore; Daniel Ross; (Ballston Lake, NY)
; Sherwood; Robert James; (Fonda, NY) |
Assignee: |
GENERAL ELECTRIC COMPANY
Schenectady
NY
|
Family ID: |
46511587 |
Appl. No.: |
13/019018 |
Filed: |
February 1, 2011 |
Current U.S.
Class: |
415/213.1 |
Current CPC
Class: |
F01D 25/265 20130101;
F01D 25/24 20130101; F05D 2220/31 20130101 |
Class at
Publication: |
415/213.1 |
International
Class: |
F01D 25/28 20060101
F01D025/28 |
Claims
1. A steam turbine inner casing stiffening system comprising: an
inner casing segment; and a stiffening member affixed to and
extending radially outward from an external surface of the inner
casing segment, the stiffening member configured to support at
least a portion of the inner casing segment.
2. The steam turbine inner casing stiffening system of claim 1,
wherein the stiffening member extends axially along the external
surface of the inner casing segment.
3. The steam turbine inner casing stiffening system of claim 1,
wherein the stiffening member extends at least partially annularly
along the external surface of the inner casing segment.
4. The steam turbine inner casing stiffening system of claim 1,
wherein the stiffening member includes an axially extending portion
and an at least partially annularly extending portion.
5. The steam turbine inner casing stiffening system of claim 1,
wherein inner casing segment includes a steam inlet.
6. The steam turbine inner casing stiffening system of claim 5,
further comprising an at least partially radially extending
stiffening member disposed about an external surface of the steam
inlet.
7. The steam turbine inner casing stiffening system of claim 5,
wherein the stiffening member includes an attachment member
configured to receive a displacement member for actuating movement
of the inner casing segment.
8. The steam turbine inner casing stiffening system of claim 1,
wherein the stiffening member extends through an inner surface of
the inner casing segment.
9. A steam turbine inner casing stiffening system comprising: an
inner casing segment having a first half and a second half; and a
plurality of stiffening members disposed about and extending
radially outward from an external surface of the first half or the
second half of the inner casing segment, the plurality of
stiffening members configured to support at least one of the first
half or the second half of the inner casing segment.
10. The steam turbine inner casing stiffening system of claim 9,
wherein each of the plurality of stiffening members extend axially
along the external surface of the first half or the second half of
the inner casing segment.
11. The steam turbine inner casing stiffening system of claim 9,
wherein at least one of the plurality of stiffening members extend
at least partially annularly along the external surface of the
first half or the second half of the inner casing segment.
12. The steam turbine inner casing stiffening system of claim 9,
wherein at least one of the plurality of stiffening members include
an axially extending stiffening member and an at least partially
annularly extending stiffening member.
13. The steam turbine inner casing stiffening system of claim 9,
wherein the first half of the inner casing segment includes a steam
inlet.
14. The steam turbine inner casing stiffening system of claim 13,
further comprising an at least partially radially extending
stiffening member disposed about an external surface of the steam
inlet.
15. The steam turbine inner casing stiffening system of claim 13,
wherein at least one of the plurality of axially extending
stiffening members disposed about the external surface of the first
half includes an attachment member configured to receive a
displacement member for actuating movement of the first half of the
inner casing segment.
16. The steam turbine inner casing stiffening system of claim 9,
wherein one of the plurality of stiffening members extends through
an inner surface of the second half of the inner casing
segment.
17. A steam turbine comprising: a rotor member; and a stator member
at least partially surrounding the rotor member, the stator member
including: an external casing; and an inner casing stiffening
system disposed between the external casing and the rotor member,
the inner casing stiffening system including: an inner casing
segment; and a stiffening member affixed to and extending radially
outward from an external surface of the inner casing segment, the
stiffening member configured to support at least a portion of the
inner casing segment.
18. The steam turbine of claim 17, wherein the stiffening member
extends axially along the external surface of the inner casing
segment.
19. The steam turbine of claim 17, wherein the stiffening member
extends at least partially annularly along the external surface of
the inner casing segment.
20. The steam turbine of claim 17, wherein the stiffening member
include an axially extending portion and an at least partially
annularly extending portion.
Description
BACKGROUND OF THE INVENTION
[0001] The subject matter disclosed herein relates to a steam
turbine casing. Specifically, the subject matter disclosed herein
relates to a steam turbine casing including an externally disposed
stiffening system.
[0002] Conventional steam turbine casings include stiffening
structures disposed along the interior of the inner casing wall. In
some instances, these stiffening structures extend through the
width of the inner casing wall and remain flush with the outer
portion of the inner casing wall. However, in all instances, these
conventional stiffening structures include stiffening members
extending into the steam flow path on the interior of the inner
casing wall. These stiffening structures may cause clearance and
flow-related issues in the steam turbine.
BRIEF DESCRIPTION OF THE INVENTION
[0003] A steam turbine casing stiffening system is disclosed. In
one embodiment, a steam turbine inner casing stiffening system is
disclosed, including: an inner casing segment; and a stiffening
member affixed to and extending radially outward from an external
surface of the inner casing segment, the stiffening member
configured to stiffen at least a portion of the inner casing
segment.
[0004] A first aspect of the invention includes a steam turbine
inner casing stiffening system having: an inner casing segment; and
a stiffening member affixed to and extending radially outward from
an external surface of the inner casing segment, the stiffening
member configured to stiffen at least a portion of the inner casing
segment.
[0005] A second aspect of the invention includes a steam turbine
inner casing stiffening system having: an inner casing segment
having a first half and a second half; and a plurality of
stiffening members disposed about and extending radially outward
from an external surface of the first half or the second half of
the inner casing segment, the plurality of stiffening members
configured to stiffen at least one of the first half or the second
half of the inner casing segment.
[0006] A third aspect of the invention includes a steam turbine
having: a rotor member; and a stator member at least partially
surrounding the rotor member, the stator member including: an
external casing; and an inner casing stiffening system disposed
between the external casing and the rotor member, the inner casing
stiffening system including: an inner casing segment; and a
stiffening member affixed to and extending radially outward from an
external surface of the inner casing segment, the stiffening member
configured to stiffen at least a portion of the inner casing
segment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] These and other features of this invention will be more
readily understood from the following detailed description of the
various aspects of the invention taken in conjunction with the
accompanying drawings that depict various embodiments of the
invention, in which:
[0008] FIG. 1 shows a three-dimensional perspective view of a steam
turbine inner casing stiffening system according to embodiments of
the invention.
[0009] FIG. 2 shows a three-dimensional perspective view of a steam
turbine inner casing stiffening system according to embodiments of
the invention.
[0010] FIG. 3 shows a partial cut-away top view of inner casing
stiffening system according to embodiments of the invention.
[0011] FIG. 4 shows a partial cut-away bottom view of inner casing
stiffening system according to embodiments of the invention.
[0012] FIG. 5 shows a three-dimensional perspective view of a
plurality of stiffening bars, arranged in different circumferential
positions, according to embodiments of the invention.
[0013] FIG. 6 shows a rough schematic cut-away top view of a
portion of a steam turbine apparatus according to embodiments of
the invention.
[0014] It is noted that the drawings of the invention are not to
scale. The drawings are intended to depict only typical aspects of
the invention, and therefore should not be considered as limiting
the scope of the invention. In the drawings, like numbering
represents like elements between the drawings.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Aspects of the invention provide for a steam turbine casing.
Specifically, the subject matter disclosed herein relates to a
steam turbine inner casing including an externally disposed
stiffening system.
[0016] As described herein, conventional steam turbine casings
include stiffening structures disposed along the interior of the
inner casing wall. In some instances, these stiffening structures
extend through the width of the inner casing wall and remain flush
with the outer portion of the inner casing wall. However, in all
instances, these conventional stiffening structures include
stiffening members extending into the steam flow path on the
interior of the inner casing wall. These stiffening structures may
cause clearance and steam sealing issues within the steam
turbine.
[0017] In contrast to conventional stiffening structures for steam
turbine inner casings, aspects of the invention provide for an
external stiffening system for an inner steam turbine casing,
providing for minimal impact on the steam flow path. In some
embodiments, the stiffening system includes substantially parallel
axially extending members disposed (e.g., affixed) annularly about
the outer surface of the inner steam turbine casing.
[0018] In other embodiments, the stiffening system includes
substantially parallel annularly extending members disposed axially
about the outer surface of the inner steam turbine casing. In this
embodiment, the stiffening system may include a plurality of
annular rings disposed along (e.g., affixed to) the outer surface
of the inner casing in the axial direction.
[0019] In other embodiments, the stiffening system includes both
annularly extending members and axially extending members providing
stiffening along the outer surface of the inner casing. In yet
other embodiments, stiffening members may extend partially axially
and partially annularly along the outer surface of the inner
casing. In any case, the technical effect of the stiffening systems
described herein is to provide mechanical stiffening for a steam
turbine inner casing without disrupting the steam flow path and
sealing surfaces inside the inner casing.
[0020] Turning to FIG. 1, a three-dimensional perspective view of a
steam turbine inner casing stiffening system 2 is shown according
to embodiments. In this embodiment, the steam turbine inner casing
stiffening system 2 includes an inner casing segment 4, and a
stiffening member 6 (a plurality shown) affixed to and extending
radially outward from an external surface 8 (or, wrapper external
surface) of the inner casing segment 4. In one embodiment, the
stiffening member 6 is configured to stiffening (e.g., mechanically
support) at least a portion of the inner casing segment 4. In
contrast to conventional stiffening systems for inner casing
segments (e.g., inner casing segment 4), the stiffening system 2
shown and described herein includes radially outwardly extending
stiffening member(s) 6, which do not extend into the steam flow
path defined on the internal surface 10 of the inner casing segment
4.
[0021] In one embodiment, the stiffening member(s) 6 extend axially
along the external surface 8 of the inner casing segment 4. That
is, in some cases, stiffening member(s) 6 may extend in a direction
substantially parallel with the axis of the steam turbine
(indicated in phantom by the line A-A. This may allow for axial
support of the inner casing segment. In some embodiments, the
stiffening member(s) 6 may extend along an axial length of more
than one stage of the steam turbine (which is further explained
herein with respect to the stages shown and described with
reference to the internal surface 10). Further, the stiffening
member(s) 6 may extend along or across turbine section joint
segments 12 where adjacent axial sections of the inner casing are
joined. In some embodiments, stiffening member(s) 6 may have
substantially smooth radially inwardly facing surfaces (not shown
in this embodiment), which may be configured to fit substantially
flush against the substantially smooth external surfaces 8 of inner
casing segment 4. These substantially smooth radially inward facing
surfaces are dissimilar to the radially inward facing surfaces of
conventional stiffening structures for inner casing segments, as
those conventional stiffening structures are located along the
internal surfaces (e.g., internal surface 10) of the inner casing
segment and are corrugated to mate with internal steam flow path
components.
[0022] In one embodiment, at least one stiffening member 6 may
include an attachment member 14 configured to receive a
displacement member (not shown) for actuating movement of the inner
casing segment 4. In one embodiment, the attachment member 14 may
be a loop (either closed or adaptable to open), a hook, a notch,
etc., configured to receive a displacement member, which may
similarly be a loop (either closed or adaptable to open), a hook, a
notch, etc., configured to mate with the attachment member 14. One
or more displacement members may attach to the one or more
attachment members 14 (e.g., as shown, at least two) to actuate
movement of the inner casing segment 4. In some cases, attachment
member(s) 14 may allow for placement, removal and/or replacement of
inner casing segment 4 from a steam turbine system.
[0023] It is understood that as shown, inner casing segment 4
includes a portion of an upper half of a steam turbine inner
casing. In a complete steam turbine inner casing section, this
inner casing segment 4 will be joined at a horizontal joint surface
with a second inner casing segment (e.g., a lower half of a steam
turbine inner casing) that will form one or more steam paths around
a rotor. As shown, inner casing segment 4 (and its counterpart
lower casing segment, shown and described with respect to FIG. 2)
is part of a double-flow steam turbine system. However, it is
understood that the teachings described herein may be applied to
axial flow steam turbine systems as well.
[0024] Also included in inner casing segment is an inlet 16 for
receiving steam flow through a steam flow path 18. In the case that
the inner casing segment 4 is an upper half of a double-flow steam
turbine inner casing segment (e.g., in a low pressure section),
inlet 16 will allow steam to flow through flow path 18 and divide
between axially forward and axially rearward sections of the steam
turbine. Inlet 16 has an external surface 20 and an internal
surface (not shown), and in some embodiments, a stiffening member 6
may be affixed to an external surface 20 of inlet 16. In one
embodiment, the stiffening member(s) 6 may extend axially across
surface 20 (sometimes referred to herein as axially extending
stiffening members), while in another embodiment, stiffening
member(s) 6 may extend at least partially radially along the
surface 20 of inlet 16 (e.g., substantially parallel with flow path
18).
[0025] In another embodiment, axially extending stiffening
member(s) 6 may include, or be operably connected with one or more
annularly extending stiffening members 22, configured to provide
radial support to the inner casing segment 4. In some cases,
annularly extending stiffening members 22 may be connected to
axially extending stiffening members 6 via welds, pins, clamps,
adhesives, etc. In other cases, these stiffening members (6, 22)
may be integrally cast or formed form a continuous pieces of
material. As described herein, stiffening members (e.g., axially
extending stiffening members 6 and/or annularly extending
stiffening members 22) may be formed of a metal (e.g., steel) or
composite capable of providing support to the inner casing segment.
While stiffening members (e.g., axially extending stiffening
members 6 and/or annularly extending stiffening members 22) are
shown running substantially parallel, or substantially
perpendicular with the steam turbine's central axis A, it is
understood that one or more stiffening members may be configured to
extend at least partially annularly and at least partially axially
along external surface 8 (e.g., diagonally between portions of
external surface). In this case, the stiffening member may provide
both axial and radial support to inner casing segment 4.
[0026] It is understood that the axially extending stiffening
member(s) 6 described herein may allow for axial stiffening of
inner casing segment 4, thereby aiding in the retention of axial
joints formed between one or more casing segments (e.g., inner
casing segment 4 and an adjoining segment, further described
herein). However, in some embodiments, where the steam turbine
inner casing is radially sealed, the annularly extending stiffening
members 22 may aid in retaining radial joints formed between one or
more casing segments.
[0027] Turning to FIG. 2, a three-dimensional perspective view of a
steam turbine inner casing stiffening system 24 is shown according
to embodiments of the invention. In this embodiment, the inner
casing stiffening system 24 includes a second inner casing segment
26 (e.g., a lower half of an inner casing segment configured to
mate with the inner casing segment 4 of FIG. 1). It is understood
that like numbering between figures may represent substantially
like elements. As shown, the inner casing stiffening system 24
includes stiffening bars 28 configured to retain the inner casing
segment 26 within an external casing segment (e.g., a lower
external casing segment) as is known in the art. As is similarly
described with reference to FIG. 1 and inner casing segment 4, one
or more stiffening bars 6 may be disposed about one or more of the
external surfaces 8 of second inner casing segment 26, thereby
providing support to second inner casing segment 26. Further,
annularly extending stiffening bars 22 may also be disposed about
one or more of the external surfaces 8 of second inner casing
segment 26, e.g., to provide radial support.
[0028] Turning to FIGS. 3-4, a partial cut-away top view of inner
casing stiffening system 2 (including inner casing segment 4), and
a partial cut-away bottom view of inner casing stiffening system 24
(including second inner casing segment 26), respectively, are shown
according to embodiments of the invention. As mentioned herein, in
some instances, the inner casing is referred to as a "wrapper." For
ease of reference in FIGS. 3-4, inner casing segment 4 is referred
to as upper casing segment, while second inner casing segment 26 is
referred to as lower casing segment.
[0029] Upper casing segment 4 and lower casing segment 26 include a
plurality of steam flow channels 30, which extend substantially
annularly about a rotor apparatus (omitted for clarity of
illustration). That is, the steam flow channels 30 illustrated in
FIGS. 3-4 extend between the lower casing segment 26 and upper
casing segment 4 so as to provide a continuous steam flow path
about the central axis A (indicated in phantom) when the casing
segments are adjoined. Separating the steam flow channels 30 are
annular ledge rings 32, which allow for fluid isolation between
different stages of the low pressure steam turbine. As will be
described further herein, ledge rings 32 extend substantially
radially inwardly from the inner casing wall, and aid in defining
the steam flow channels 30. In contrast to conventional inner
casing stiffening systems, aspects of the invention allow for
minimal impact on the steam flow channels 30 by the stiffening
system (including, e.g., stiffening bars 6 and/or stiffening bars
22) described herein. For example, as shown in FIGS. 3-4, only a
portion of stiffening bar 6 may extend through the interior surface
10 of upper casing segment 4.
[0030] FIG. 5 shows a three-dimensional perspective view of a
plurality of stiffening bars 6, arranged in different
circumferential positions, according to embodiments of the
invention. As described with reference to FIG. 1, stiffening bars 6
may include substantially smooth radially inward surfaces (or,
faces) 34, which may be configured to attach flush against one or
more external surfaces of an inner casing segment (e.g., external
surfaces 8). Additionally, as described with reference to FIG. 1,
one or more stiffening bars 6 may include at least one attachment
member 14.
[0031] FIG. 6 shows a rough schematic cut-away top view of a
portion of a steam turbine 36 according to embodiments of the
invention. The steam turbine 36 may include a rotor member 38
affixed to one or more buckets 40, and a stator member 42 at least
partially surrounding the rotor member 38. The stator member 42 may
include an external casing 44 and an inner casing stiffening system
46 (hidden from this cut-away view) Inner casing stiffening system
46 may be positioned radially inward of external casing 44 (between
external casing 44 and rotor member 38), and may include an inner
casing 48 (having a plurality of inner casing segments, such as
inner casing segments 4, 24). It is understood that the inner
casing stiffening system 46 may include one or more components
described with reference to the inner casing stiffening systems 2,
24 of FIGS. 1-2. That is, although not visible from this
perspective, inner casing stiffening system 46, a portion of which
is included in steam turbine apparatus 36, may include one or more
inner casing segments (e.g., inner casing segments 4, 24) and one
or more stiffening members (e.g., stiffening members 6, 22)
described herein. In contrast to conventional steam turbine
apparatuses, the steam turbine apparatus 36 shown according to
embodiments allows for stiffening of the inner casing 48 with
minimal effect on the steam flow path between the rotor member 38
(and buckets 40) and the interior surfaces of inner casing 48.
[0032] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the disclosure. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
[0033] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
* * * * *