U.S. patent application number 10/248172 was filed with the patent office on 2004-06-24 for methods and apparatus for securing turbine nozzles.
This patent application is currently assigned to GENERAL ELECTRIC COMPANY. Invention is credited to Couture, Bernard Arthur, Korzun, Ronald Wayne.
Application Number | 20040120813 10/248172 |
Document ID | / |
Family ID | 32592774 |
Filed Date | 2004-06-24 |
United States Patent
Application |
20040120813 |
Kind Code |
A1 |
Couture, Bernard Arthur ; et
al. |
June 24, 2004 |
METHODS AND APPARATUS FOR SECURING TURBINE NOZZLES
Abstract
A method for assembling a turbine, wherein the method includes
coupling at least one nozzle assembly including an outer band, an
inner band, a nozzle, and a dovetail, to a stator that includes a
plurality of dovetail slots and channels defined therein, slidably
coupling the at least one nozzle assembly into a respective
dovetail slot, and fixedly securing the at least one nozzle
assembly to the stator with a load pin that extends between the
nozzle assembly and the dovetail slot.
Inventors: |
Couture, Bernard Arthur;
(Schenectady, NY) ; Korzun, Ronald Wayne; (Clifton
Park, NY) |
Correspondence
Address: |
JOHN S. BEULICK
C/O ARMSTRONG TEASDALE, LLP
ONE METROPOLITAN SQUARE
SUITE 2600
ST LOUIS
MO
63102-2740
US
|
Assignee: |
GENERAL ELECTRIC COMPANY
1 River Road
Schenectady
NY
|
Family ID: |
32592774 |
Appl. No.: |
10/248172 |
Filed: |
December 23, 2002 |
Current U.S.
Class: |
415/209.2 ;
29/889.22; 415/209.4 |
Current CPC
Class: |
F01D 25/246 20130101;
Y10T 29/49323 20150115; F05D 2220/31 20130101; F01D 9/041 20130101;
F05D 2230/64 20130101 |
Class at
Publication: |
415/209.2 ;
415/209.4; 029/889.22 |
International
Class: |
F01D 009/04 |
Claims
1. A method for assembling a turbine, said method comprising:
coupling at least one nozzle assembly including an outer band, an
inner band, a nozzle, and a dovetail, to a stator that includes a
plurality of dovetail slots and channels defined therein; slidably
coupling the at least one nozzle assembly into a respective
dovetail slot; and fixedly securing the at least one nozzle
assembly to the stator with a load pin that extends between the
nozzle assembly and the dovetail slot.
2. A method in accordance with claim 1 further comprising forming a
channel that extends at least partially through the stator dovetail
slot and is sized to receive a load pin therein.
3. A method in accordance with claim 1 wherein fixedly securing the
at least one nozzle assembly to the stator comprises inserting the
load pin through the stator channel.
4. A method in accordance with claim 1 further comprising forming a
plurality of channels that each extend at least partially through
the stator dovetail slot, and are sized to receive at least one
load pin therein.
5. A method in accordance with claim 1 wherein fixedly securing the
at least one nozzle assembly further comprises fixedly securing the
at least one nozzle assembly to the stator using at least one load
pin that has a substantially semi-circular cross-sectional
shape.
6. A method in accordance with claim 1 wherein fixedly securing the
at least one nozzle assembly further comprises fixedly securing the
at least one nozzle assembly to the stator using at least one load
pin fabricated from at least one of a brass, a bronze, and a steel
material.
7. A stator assembly for a turbine, said stator assembly
comprising: a stator comprising a plurality of dovetail slots and
channels; at least one nozzle assembly secured to said stator, said
at least one nozzle assembly comprising an outer band, an inner
band, a nozzle, and a dovetail, said nozzle extending radially
outwardly from each said dovetail; and at least one load pin for
securing said at least one nozzle assembly to said stator such that
said load pin extends between said at least one nozzle assembly
dovetail and said at least one stator dovetail slot.
8. A stator assembly in accordance with claim 7 wherein said at
least one load pin comprises a substantially semi-circular
cross-sectional profile.
9. A stator assembly in accordance with claim 7 wherein said at
least one load pin comprises at least one of a brass, a bronze, and
a steel material.
10. A stator assembly in accordance with claim 7 wherein said at
least one load pin extends through a portion of said stator
dovetail slot.
11. A stator assembly in accordance with claim 7 wherein said at
least one load pin extends through a portion of said stator
channel.
12. A stator assembly in accordance with claim 7 wherein said at
least one load pin further comprises an upstream load pin and a
downstream load pin.
13. A turbine comprising: at least one rotor assembly; at least one
stator assembly in flow communication with said at least one rotor
assembly, said at least one stator assembly comprising a stator
comprising a plurality of dovetail slots and channels; at least one
nozzle assembly secured to said stator, said at least one nozzle
assembly comprising an upstream side, a downstream side, a vane and
a dovetail, said vane extending radially from said dovetail; and at
least one load pin for securing said at least one nozzle assembly
to said stator such that said load pin extends between said nozzle
assembly dovetail and said stator dovetail slot.
14. A turbine in accordance with claim 13 wherein said at least one
load pin comprises a substantially semi-circular cross-sectional
profile.
15. A turbine in accordance with claim 13 wherein said at least one
load pin comprises at least one of a brass, a bronze, and a steel
material.
16. A turbine in accordance with claim 13 wherein said at least one
load pin extends through a portion of said stator channel.
17. A turbine in accordance with claim 13 wherein said at least one
load pin extends through a portion of said stator dovetail
slot.
18. A turbine in accordance with claim 13 wherein said at least one
load pin further comprises an upstream load pin and a downstream
load pin.
Description
BACKGROUND OF INVENTION
[0001] This invention relates generally to turbine engine and more
particularly, to methods and apparatus for securing turbine
nozzles.
[0002] At least some known turbine stator assemblies include a
plurality of stationary turbine nozzles that channel flow towards a
turbine. More specifically the nozzles are arranged in
axially-spaced stages within a turbine stator and each nozzle
includes an airfoil vane that extends outwardly from a dovetail
that couples the nozzle to a complimentary-shaped slot defined in
the stator.
[0003] An overall operating efficiency of a turbine engine is
related to the flow dynamics within the turbine, and as such,
engine efficiency may be limited by the ability of aerodynamic
components to remain in alignment. Moreover, securing aerodynamic
components, such as nozzle assemblies, facilitates reducing flow
variations and increasing engine efficiency.
[0004] However, during operation, the nozzles may be urged in a
tangential direction as steam flows through the nozzle vanes. The
loads are transmitted from the nozzles to the stator through the
complementary dovetail surfaces. However, overtime the stress
loading may loosen the nozzle dovetail with regard to the slot, and
as a result, a useful life of the nozzle may be reduced.
SUMMARY OF INVENTION
[0005] In one aspect, a method is provided for assembling a
turbine. The method includes coupling at least one nozzle assembly
including an outer band, an inner band, a nozzle, and a dovetail,
to a stator that includes a plurality of dovetail slots and
channels defined therein, slidably coupling the at least one nozzle
assembly into a respective dovetail slot, and fixedly securing the
at least one nozzle assembly to the stator with a load pin that
extends between the nozzle assembly and the dovetail slot.
[0006] In another aspect, a stator assembly for a turbine is
provided including a stator that includes a plurality of dovetail
slots and channels, at least one nozzle assembly secured to the
stator, wherein the at least one nozzle assembly includes an outer
band, an inner band, a nozzle, and a dovetail, and wherein the
nozzle extends radially outwardly from each dovetail. The stator
assembly also includes at least one load pin for securing the at
least one nozzle assembly to the stator such that the load pin
extends between the at least one nozzle assembly dovetail and the
at least one stator dovetail slot.
[0007] In yet another aspect, a turbine is provided that includes
at least one rotor assembly, at least one stator assembly in flow
communication with the at least one rotor assembly, wherein the at
least one stator assembly includes a stator that includes a
plurality of dovetail slots and channels. The turbine also includes
at least one nozzle assembly that is secured to the stator, wherein
the at least one nozzle assembly includes an upstream side, a
downstream side, a vane and a dovetail, and wherein the vane
extends radially from the dovetail. The turbine further includes at
least one load pin for securing the at least one nozzle assembly to
the stator such that the load pin extends between the nozzle
assembly dovetail and the stator dovetail slot.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 is a partial perspective of an exemplary turbine
engine;
[0009] FIG. 2 is an enlarged schematic cross-sectional view of a
portion of the turbine engine shown in FIG. 1;
[0010] FIG. 3 is an enlarged cross-sectional side view of a load
pin used in the turbine nozzle assembly shown in FIG. 2; and
[0011] FIG. 4 is an end view of the load pin shown in FIG. 3.
DETAILED DESCRIPTION
[0012] FIG. 1 is a partial perspective view of a steam turbine 10
including a rotor assembly 12 and a stator assembly 14. Rotor
assembly 12 includes a shaft 16 and a plurality of bucket
assemblies 18. Each bucket assemblies 18 include a plurality of
buckets 20 arranged in rows extending circumferentially around
shaft 16.
[0013] Stator assembly 14 includes a stator 22 and a plurality of
nozzle assemblies 28. Nozzle assemblies 28 include a plurality of
nozzles 30 arranged in rows extending inward circumferentially
around stator 22. Nozzles 30 cooperate with buckets 20 to form a
turbine stage and to define a portion of a steam flow path through
turbine 10.
[0014] In operation, steam 24 enters an inlet 26 of turbine 10 and
is channeled through nozzles 30. Nozzles 30 direct steam 24
downstream against buckets 20. Steam 24 passing through the turbine
stages imparts a force on buckets 20 causing shaft 16 to rotate. At
least one end of turbine 10 may extend axially away from shaft 16
and may be attached to a load or machinery (not shown), such as,
but not limited to, a generator, and/or another turbine.
Accordingly, a large steam turbine unit may actually include
several turbines that are all co-axially coupled to the same shaft
16. Such a unit may, for example, include a high-pressure turbine
coupled to an intermediate-pressure turbine, which is coupled to a
low-pressure turbine. In one embodiment, steam turbine 10 is
commercially available from General Electric Power Systems,
Schenectady, N.Y.
[0015] FIG. 2 is an enlarged schematic cross-sectional view of a
portion of turbine engine 10 shown in Figure including rotor
assembly 12 and stator assembly 14. Each stator assembly 14
includes a plurality of dovetail slots 32 and channels 33, and at
least one radial load pin 34. Dovetail slots 32 are circular or
arcuate in configuration when viewed axially and facilitates
coupling each nozzle assembly 28 to stator 22. Dovetail slots 32
are defined by a first side slot wall 35 and a second side slot
wall 36 and a radially inward slot wall 37. Substantially annular
retaining rings 38 extend from each side slot wall 35 and 36.
Channels 33 are generally complimentary in shape to load pins 34.
In the exemplary embodiment, a pair of channels 33 extend along
each inward slot wall 37 configured to receive at least one radial
load pin 34.
[0016] Nozzle assemblies 28 include nozzles 30 that each include an
airfoil 42 that extends between a radially outer band 44 and a
radially inner band 46. Nozzle dovetail 40 extends radially outward
from airfoil 42. Airfoil 42 includes a first contoured sidewall 48
and second contoured sidewall 50. First sidewall 48 is convex and
defines a suction side of airfoil 42. Second sidewall 50 is concave
and defines a pressure side of airfoil 42. Sidewalls 48, 50 are
joined at a leading edge 52 and at an axially spaced trailing edge
54 of airfoil 42.
[0017] Nozzle dovetail 40 is generally complimentary in shape to
stator dovetail slots 32. Nozzle dovetail 40 includes an upstream
side 56 and a downstream side 58. In the exemplary embodiment,
upstream side 56 and downstream side 58 are parallel. Nozzle
assemblies 28 has a first axial face 60 and an opposite second
axial face 62 that each extend between upstream and downstream
sides 56, 58. Upstream side 56 includes a side shoulder 64, known
as an outer tang, that extends substantially perpendicularly from
upstream side 56 and defines an overhang 66. A dovetail tang 68
also extends substantially perpendicularly from the upstream side
56 and is substantially parallel to the side shoulder 64, such that
an upstream side slot 70 is defined between dovetail tang 68 and
shoulder 64.
[0018] Nozzle assembly downstream side 58 includes a side shoulder
72 that extends substantially perpendicularly from downstream side
58. In an exemplary embodiment, shoulder 72 is substantially
co-axially aligned with respect to upstream shoulder 64. Side
shoulder 72 defines a downstream side overhang 74. A dovetail tang
76 also extends substantially perpendicularly from the downstream
side 58 and is substantially parallel to side shoulder 72, such
that a downstream side slot 78 is defined between. In the exemplary
embodiment, downstream dovetail tang 76 is substantially co-axially
aligned with respect to upstream dovetail tang 68.
[0019] During assembly of stator assembly 14, each respective
nozzle assembly 28 is inserted into dovetail slot 32, then
circumferentially slid through dovetail slot 32. Nozzle assemblies
28 are then secured to stator 22 by inserting at least one radial
load pin 34 into at least one channel 33. Additional nozzle
assemblies 28 are then slidably coupled to stator assembly 14 in a
similar fashion about stator 22.
[0020] Load pin 34 is substantially elongate, and is disposed in
channel 33 having a substantially semi-circular cross-sectional
profile. In one embodiment, channel 33 extends from slot wall 37
through dovetail slot 32. Load pin 34 secures each nozzle assembly
28 to stator 22.
[0021] FIG. 3 is an enlarged cross-sectional side view of load pin
34 used in the turbine nozzle assembly 28 shown in FIG. 2. FIG. 4
is an end view of load pin 34 shown in FIG. 3. Load pin 34 includes
a first end 100, a second end 102, and a body 104 extending
therebetween. Load pin 34 has a substantially semi-circular
cross-sectional profile that includes a substantially circular
portion 106 with a center point 107 and a radius 108, and a
substantially straight portion 110. Load pin 34 further includes a
length 112 and a height 114. In the exemplary embodiment, radius
108 is approximately 0.158, length 112 is approximately 0.920, and
height 114 is approximately 0.200. In one embodiment, radius 108 is
approximately between 0.157 and 0.159, length 112 is approximately
between 0.915 and 0.925, and height 114 is approximately between
0.198 and 0.202. In another embodiment, radius 108 is approximately
between 0.153 and 0.163, length 112 is approximately between 0.910
and 0.930, and height 114 is approximately between 0.195 and 0.205.
In the exemplary embodiment, load pin 34 is fabricated from brass.
In another embodiment, load pin 34 is fabricated from bronze. In an
alternate embodiment, load pin 34 is fabricated from steel.
[0022] The above-described stator assembly is efficient and
cost-effective device. The stator assembly includes a radial load
pin that facilitates securing a nozzle assembly to the stator
assembly, thus reducing the chances of unpredictable flow path
dynamics. Furthermore, the radial load pin is inexpensive and easy
to manufacture. As a result, the radial load pin facilitates
stabilizing flow path dynamics in an efficient and cost-effective
manner.
[0023] Exemplary embodiments of stator and nozzle assemblies are
described above in detail. The systems are not limited to the
specific embodiments described herein, but rather, components of
each assembly may be utilized independently and separately from
other components described herein. Each stator and nozzle assembly
component can also be used in combination with other stator and
nozzle assemblies and turbine components.
[0024] While the invention has been described in terms of various
specific embodiments, those skilled in the art will recognize that
the invention can be practiced with modification within the spirit
and scope of the claims.
* * * * *