U.S. patent application number 09/997235 was filed with the patent office on 2003-06-05 for steam turbine nozzle plate having 360 discharge.
Invention is credited to Ahl, Dennis Roger, Chevrette, Richard Jon, Farineau, Thomas Joseph, Hamlin, Michael Thomas, Hilt, George Edward JR., Kim, Tai Joung, Palmer, Jeffrey Louis, Vogan, James Harvey.
Application Number | 20030103845 09/997235 |
Document ID | / |
Family ID | 25543780 |
Filed Date | 2003-06-05 |
United States Patent
Application |
20030103845 |
Kind Code |
A1 |
Hamlin, Michael Thomas ; et
al. |
June 5, 2003 |
Steam turbine nozzle plate having 360 discharge
Abstract
An inner shell of a steam turbine has discrete arcuate steam
outlet ports through an axial face. In axial opposition is a nozzle
ring including a pair of nozzle ring segments joined at a
horizontal midline. At the midline joint, split partitions are
employed to provide a full 360.degree. discharge through the nozzle
ring. The split partitions are split in an axial direction to
define discrete partition portions in each of the nozzle ring
segments adjacent the midline joint.
Inventors: |
Hamlin, Michael Thomas;
(Schoharie, NY) ; Ahl, Dennis Roger; (Sprakers,
NY) ; Vogan, James Harvey; (Schenectady, NY) ;
Kim, Tai Joung; (Schenectady, NY) ; Palmer, Jeffrey
Louis; (Schenectady, NY) ; Farineau, Thomas
Joseph; (Schoharie, NY) ; Chevrette, Richard Jon;
(Troy, NY) ; Hilt, George Edward JR.;
(Schenectady, NY) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
8th Floor
1100 North Glebe Road
Arlington
VA
22201
US
|
Family ID: |
25543780 |
Appl. No.: |
09/997235 |
Filed: |
November 30, 2001 |
Current U.S.
Class: |
415/191 ;
415/202; 415/209.2 |
Current CPC
Class: |
F01D 9/04 20130101 |
Class at
Publication: |
415/191 ;
415/202; 415/209.2 |
International
Class: |
F01D 009/04 |
Claims
What is claimed is:
1. A nozzle plate for a turbine comprising: nozzle plate segments
forming an annular array of nozzles, each segment including inner
and outer band portions and circumferentially spaced partitions
extending between said inner and outer band portions, adjacent ends
of said segments forming a joint therebetween; at least one of said
joints including a split partition with a first portion of the
split partition forming part of an end of one segment and a second
portion of the split partition forming part of an adjacent end of
another segment.
2. A nozzle plate according to claim 1 including a port bridge
disposed in front of said split partition.
3. A nozzle plate according to claim 1 wherein each of said
segments subtends an arc of 180.degree., another of said joints
between said segments including a second split partition with a
first portion thereof forming part of an end of said one segment
and a second portion thereof forming part of an adjacent end of
said another segment.
4. A nozzle plate according to claim 3 including a port bridge
disposed between said inner and outer bands in an upstream
direction relative to said split partitions.
5. A nozzle plate according to claim 1 wherein the split partition
is split in an axial direction.
6. A nozzle plate according to claim 1 wherein each of said
segments subtends an arc of 180.degree., another of said joints
between said segments including a second partition split in an
axial direction with a first portion thereof forming part of an end
of said one segment and a second portion thereof forming part of an
adjacent end of said another segment, said split partitions being
split in axial directions.
7. A nozzle plate according to claim 1 wherein each of said
segments subtends an arc of 180.degree., another of said joints
between said segments including a second partition split in an
axial direction with a first portion thereof forming part of an end
of said one segment and a second portion thereof forming part of an
adjacent end of said another segment, including a port bridge
disposed in front of each said split partition, and a weld buildup
between a leading edge of each split partition and the port
bridge.
8. A steam turbine comprising: an inner shell having an axial face
and a plurality of axially opening arcuately shaped steam outlet
ports about said face with bridging portions between said outlet
ports, a pair of said bridging portions being located at a
horizontal midline of the turbine; a plurality of nozzle segments
forming an annular array of nozzles in axial registration with said
axial faces of said inner shell, each segment including inner and
outer band portions and circumferentially spaced partitions
extending between said inner and outer band portions, adjacent ends
of said segments forming joints therebetween with a pair of said
joints lying along said horizontal midline of the turbine; the
joints between said segments along said horizontal midline lying in
axial registration with bridging portions of the inner shell at
said horizontal midline, each joint including a split partition
with a first portion of the split partition forming part of an end
of one segment and a second portion of the split partition forming
part of an end of the adjacent segment, thereby enabling steam flow
through adjacent outlet ports on opposite sides of the horizontal
midline to in part flow along opposite sides of said split
partition.
9. A turbine according to claim 8 including a port bridge disposed
in front of each said split partition.
10. A turbine according to claim 8 wherein each of said segments
subtends an arc of 180.degree..
11. A turbine according to claim 8 including a port bridge disposed
in front of each said split partition, and a weld buildup between a
leading edge of each split partition and the port bridge.
12. A turbine according to claim 8 wherein each of said split
partitions are split in an axial direction.
13. A turbine according to claim 12 including a port bridge
disposed in front of each said split partition, and a weld buildup
between a leading edge of each split partition and the port bridge.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a steam turbine nozzle
plate for discharging steam received from discrete supply ports of
the turbine inner shell in a continuous uninterrupted 360.degree.
arc and particularly relates to a steam turbine nozzle plate having
split partitions at the horizontal midline of the turbine for
eliminating flow restrictions or blockages typical of prior nozzle
designs at the horizontal midline.
[0002] In a typical steam turbine, an inner shell is provided
having, e.g., four inlet ports for receiving steam in directions
generally normal to the axis of the turbine. Conventionally, a pair
of valved inlet ports are provided on the upper half of the inner
shell and a similar pair of valved inlet ports are provided on the
lower half of the inner shell. These discrete steam flow passages
turn the steam from a flow direction generally normal to the axis
of the turbine into a unidirectional axial flow for flow through
associated discrete steam outlet ports in an end axial face of the
inner shell. These discrete outlet ports are arcuate and are spaced
one from the other by bridging portions. For example, at the
horizontal midline of the steam turbine, the bridging portions
define the extreme ends of the outlet ports. Similarly, bridging
portions are also provided in the inner shell along the vertical
centerline of the turbine and define the opposite extreme ends of
the outlet ports. It will thus be appreciated that the steam outlet
flow through the discrete ports of the inner shell enables partial
arc admissions into the nozzles of the steam turbine depending upon
the valved inlet flows and precludes a full 360.degree. arc
admission. Typically, and with all inlet valves open, a steam
admission of about 340.degree. arc maximum is obtained.
[0003] The nozzles for the turbine typically include inner and
outer bands with stator vanes or partitions extending in generally
radial directions between the inner and outer bands. The nozzle
ring is provided in 180.degree. segments which are joined to one
another along the horizontal midline of the turbine. The axial
inlet side of the nozzle ring bears against the axial face of the
inner shell such that the nozzles receive the steam flowing through
the discrete outlet ports of the inner shell as partial arc steam
admissions. Typically, the nozzle segments, for design and other
reasons, have end blocks adjacent the horizontal midline. These end
blocks have a circumferential extent which blocks part of the
admission from the axially adjoining outlet port of the inner
shell. The nozzle segments also included port bridges which are
aligned with the vertical bridging portions of the inner shell upon
assembly. As a consequence of this construction, particularly the
large end blocks at the horizontal midline of the turbine, the
steam flow from the outlet ports of the inner shell is interrupted
by the discontinuity of the end blocks. The resulting partial arc
admission of steam to and through the nozzles has limited efforts
to upgrade flow rates through the turbine and, hence, inhibited
desired increases in efficiency.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In accordance with a preferred embodiment of the present
invention, there is provided a nozzle plate which affords increased
full load efficiency in the steam turbine through employment of a
continuous uninterrupted 360.degree. inlet nozzle design.
Particularly, the nozzle plate is fabricated similarly as prior
nozzle plates, preferably in 180.degree. segments. However, the end
blocks which previously occupied a substantial circumferential
extent of the nozzle plate are entirely eliminated and partitions
are provided which extend 360.degree. about the rotor axis without
interruption from ancillary structure. More particularly, a split
partition is provided at each of the horizontal midline joints
between the nozzle ring segments such that steam from the outlet
ports of the inner shell on opposite sides of the horizontal
midline flows along opposite sides of the split partition. Each
nozzle segment has, at the midline joint, a partition portion which
mates with another partition portion of the adjacent segment upon
assembly of the segments to form a split partition whereby steam
flows from adjacent outlet ports of the inner shell along opposite
sides, respectively, of the split partition. The partition is thus
split in the axial direction of the turbine.
[0005] Additionally, a port bridge is disposed in the nozzle in
front of each of the split partitions at the horizontal midline.
The port bridges axially register with the bridging portions
between the pairs of adjacent outlet ports of the inner shell at
opposite sides of the horizontal midline. A weld buildup is
provided between each split partition and its associated port
bridge to form a continuous surface for guiding the steam flow from
the inlet ports along respective opposite sides of the split
partition. As a consequence, full 360.degree. steam admission is
provided.
[0006] In a preferred embodiment according to the present
invention, there is provided a nozzle plate for a turbine
comprising nozzle plate segments forming an annular array of
nozzles, each segment including inner and outer band portions and
circumferentially spaced partitions extending between the inner and
outer band portions, adjacent ends of the segments forming a joint
therebetween, at least one of the joints including a split
partition with a first portion of the split partition forming part
of an end of one segment and a second portion of the split
partition forming part of an adjacent end of another segment.
[0007] In a further preferred embodiment according to the present
invention, there is provided a steam turbine comprising an inner
shell having an axial face and a plurality of axially opening
arcuately shaped steam outlet ports about the face with bridging
portions between the outlet ports, a pair of the bridging portions
being located at a horizontal midline of the turbine, a plurality
of nozzle segments forming an annular array of nozzles in axial
registration with the axial faces of the inner shell, each segment
including inner and outer band portions and circumferentially
spaced partitions extending between the inner and outer band
portions, adjacent ends of the segments forming joints therebetween
with a pair of the joints lying along the horizontal midline of the
turbine, the joints between the segments along the horizontal
midline lying in axial registration with bridging portions of the
inner shell at the horizontal midline, each joint including a split
partition with a first portion of the split partition forming part
of an end of one segment and a second portion of the split
partition forming part of an end of the adjacent segment, thereby
enabling steam flow through adjacent outlet ports on opposite sides
of the horizontal midline to in part flow along opposite sides of
the split partition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a fragmentary perspective view illustrating upper
and lower nozzle segments constructed in accordance with a
preferred embodiment of the present invention;
[0009] FIG. 2 is an enlarged fragmentary side elevational view
illustrating the nozzle ring and inner shell;
[0010] FIG. 3 is an axial end view of the axial face of the inner
shell which registers with the inlet side of the nozzle ring with
portions of the nozzle plate superimposed;
[0011] FIG. 4 is a schematic fragmentary cross-sectional view of
one of the horizontal joints of the nozzle segments in conjunction
with the inlet ports, the view being folded out in plan;
[0012] FIG. 5 is a schematic illustration of the upper and lower
nozzle ring segments folded in plan illustrating the split
partitions at the horizontal midline; and
[0013] FIG. 6 is a fragmentary view of a nozzle segment at its
horizontal joint folded out in plan view according to the prior art
illustrating the end blockage.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Referring now to the drawings, particularly to FIGS. 1 and
2, there is schematically illustrated a portion of a diaphragm,
generally designated 10, for use in steam turbines and includes a
nozzle plate or ring 12 having inner and outer bands 14 and 16,
respectively. A plurality of stator vanes or partitions 18 are
spaced circumferentially one from the other about the nozzle ring
12 and extend generally in radial directions between the inner and
outer bands 14 and 16. As illustrated in FIG. 1, the nozzle ring is
separated into preferably a pair of upper and lower nozzle ring
segments 20 and 22 which are joined one to the other along the
horizontal midline of the steam turbine at installation. As
illustrated in FIG. 2, the nozzle ring 10 forms part of the
diaphragm for receiving steam from an inner shell 24. As
illustrated in FIG. 2, the partitions 18 receive steam from outlet
ports, described below, and discharge the steam to drive the
buckets 26 of the first stage of the steam turbine rotor 28.
[0015] Referring to FIGS. 2 and 3, the inner shell 24 includes a
plurality of valved steam admission ports. In the illustrated form,
a pair of steam inlet ports 30 are formed along the upper side of
the inner shell 24, while a similar pair of valved inlet ports 30
are disposed along the lower half of the inner shell 24. The inner
shell 24 includes passages 32 associated with each of the inlet
ports 30 for turning the steam from an inlet direction generally
normal to the axis of rotation of the turbine to an axial direction
for flow through steam outlet ports 34 in the axial face 36 in
axial registration with the nozzle ring 12. From a review of FIG.
3, it will be appreciated that each steam outlet port 34 is
associated with a valved steam inlet port 30 and is generally
arcuate in configuration, each outlet port 34 subtending an arc
less than 900. Bridging portions 39 are provided adjacent steam
outlet ports 34 along opposite sides of the horizontal midline 37
and bridging portions 38 are provided along the vertical centerline
to maintain the outlet ports 34 segregated one from the other.
Valved steam admission through the segregated steam outlet ports 34
is useful when one or more of the valved inlet ports 30 are used to
supply steam while the other valved inlet port(s) do not supply
steam. Consequently, it will be appreciated that in the
illustrative embodiment, the steam inlet ports 34 are arcuate about
the rotor axis, lie in quadrants less than 90.degree. and are
separated one from the other by bridging portions 39 and 38 along
the axial face of the inner shell 24. Also illustrated in FIG. 3 is
a superimposition in schematic form of the nozzle ring 12 and
partitions 18 illustrating their location relative to the steam
inlet ports 34.
[0016] Referring to FIG. 6, there is illustrated a portion of a
prior art nozzle ring segment laid out in plan to illustrate an end
block portion 50 along the horizontal midline. Particularly as
illustrated, the nozzle ring 52 includes a plurality of partitions
54 which extend generally radially and an end block portion 50
which extends a discrete circumferential extent. The end block 50,
in combination with the end block 50 of the opposing nozzle ring
segment, as well as end blocks along the diametrically opposite
side of the nozzle ring occupy circumferential extents which
otherwise could receive a number of partitions, e.g., five or six
partitions each. It will be appreciated, however, that because of
the end block portions 50, a full 360.degree. discharge through the
nozzle ring 52 cannot be achieved.
[0017] In accordance with a preferred embodiment of the present
invention and with reference to FIGS. 4 and 5, a full 360.degree.
uninterrupted flow of steam through the nozzle ring 12 hereof is
provided. To accomplish this, the end block typically provided on
each of the upper and lower nozzle segments adjacent each of the
midline joints is entirely eliminated and replaced by a number of
additional partitions and a split partition. Particularly, the
partitions 18 are provided in the areas adjacent the midline joints
of the nozzle segments, a split partition 60 being provided at each
of the midline joints. More particularly, the split partition 60
includes along one midline joint of one of the nozzle ring segments
a suction side partition portion 62. The adjacent segment of the
nozzle ring segment includes a pressure side portion 64 of the
split partition 60. The split partition portions, upon assembly,
are joined one to the other along an axially extending split line
66, e.g., by welding. It will be appreciated that the number of
partitions 18 illustrated in FIGS. 4 and 5 are reduced from the
actual number of partitions for clarity.
[0018] For example, as illustrated in FIG. 4, the upper nozzle ring
segment 20 includes a suction side partition portion 62 along one
end thereof and a pressure side partition portion 64 along its
opposite end. The lower nozzle ring segment 22 includes a suction
side partition portion 62 and a pressure side partition portion 64
adjacent opposite ends. When the upper and lower segments 20 and 22
are assembled, the suction and pressure side portions 62 and 64,
respectively, mate with one another to form a single complete
partition 60. The partition 60 is spaced from and configured
similarly as the adjacent partitions 18 about the nozzle ring.
[0019] As illustrated in FIGS. 4 and 5, the leading edges of the
partitions 18 are axially inset from the leading edge of the nozzle
diaphragm. Additionally, strength bridges 68 are disposed between
the inner and outer rings at periodic circumferentially spaced
positions forwardly of the partitions 18. As best illustrated in
FIG. 4, it will be appreciated that each of the horizontal joints
between the upper and lower nozzle ring segments 20 and 22,
respectively, lie in axial registration with the bridging portions
36 of the inner shell 24 at the horizontal midline 37. To provide
strength to the nozzle ring and continuous flow of steam along
opposite sides of each split partition 60 from the adjacent steam
outlet ports 34, a port bridge 70 extends between the inner and
outer rings forwardly of the leading edge of the split partition
60. Additionally, a weld buildup 72 is provided between the port
bridge 70 and the split partition 60 to form the continuous surface
along opposite sides of the split partition. Similarly, at the
vertical centerlines of the nozzle segments in axial opposition to
the bridging portions 38 between the steam outlet ports 34 of the
inner shell, port bridges 74 are provided (FIG. 5). By providing
the port bridges 70 and 74, partial arc admissions of steam may be
provided from one or more of the valved inlet ports 30. It will be
appreciated, however, that when steam is provided through each of
the valved inlet ports 30 for flow through the outlet ports 34, the
nozzle ring provides a full 3600 discharge of steam onto the
buckets of that stage.
[0020] 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.
* * * * *