U.S. patent application number 11/233057 was filed with the patent office on 2007-03-29 for integrated nozzle and bucket wheels for reaction steam turbine stationary components and related method.
This patent application is currently assigned to General Electric Company. Invention is credited to Robert James Bracken, Clement Gazzillo, John Thomas Murphy, Jeffrey Simkins, Stephen Swan.
Application Number | 20070071605 11/233057 |
Document ID | / |
Family ID | 37061444 |
Filed Date | 2007-03-29 |
United States Patent
Application |
20070071605 |
Kind Code |
A1 |
Gazzillo; Clement ; et
al. |
March 29, 2007 |
Integrated nozzle and bucket wheels for reaction steam turbine
stationary components and related method
Abstract
Integrated nozzle and bucket wheels for turbine stator and rotor
components, respectively, include a three hundred sixty degree
wheel formed from a single piece of stock material. The nozzle
wheels include radially inner portions formed to include a
plurality of nozzles, while the bucket wheels are each formed to
include a plurality of buckets. The nozzle and bucket wheels may be
split into plural arcuate segments.
Inventors: |
Gazzillo; Clement;
(Schenectady, NY) ; Murphy; John Thomas;
(Niskayuna, NY) ; Swan; Stephen; (Clifton Park,
NY) ; Bracken; Robert James; (Niskayuna, NY) ;
Simkins; Jeffrey; (Rensselaer, NY) |
Correspondence
Address: |
NIXON & VANDERHYE P.C.
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Assignee: |
General Electric Company
Schenectady
NY
|
Family ID: |
37061444 |
Appl. No.: |
11/233057 |
Filed: |
September 23, 2005 |
Current U.S.
Class: |
416/222 |
Current CPC
Class: |
F01D 9/041 20130101;
F05D 2230/10 20130101; F01D 5/34 20130101 |
Class at
Publication: |
416/222 |
International
Class: |
F01D 5/30 20060101
F01D005/30 |
Claims
1. An integrated bucket wheel for a turbine rotor component
comprising a three hundred sixty degree wheel formed from a single
piece of stock material, a radially outer portion of said wheel
manufactured to include a plurality of buckets, each having an
airfoil portion and a radially outer tip shroud portion; and a
radially inner portion of said bucket wheel manufactured to include
one or more assembly features.
2. The integrated bucket wheel of claim 1 wherein said assembly
features include a plurality of tie-rod or bolt holes radially
inward of said airfoil portions.
3. The integrated bucket wheel of claim 2 wherein said tie-rod or
bolt holes are circumferentially spaced about said radially inner
portion.
4. The integrated bucket wheel of claim 1 wherein said bucket wheel
is split into two or more arcuate segments.
5. The integrated bucket wheel of claim 1 wherein said stock
material comprises a forged stock.
6. The integrated bucket wheel of claim 1 wherein said stock
material comprises rolled ring stock.
7. The integrated bucket wheel of claim 1 wherein said stock
material comprises generally flat plate stock.
8. The integrated bucket wheel of claim 1 including a center
opening adapted to receive a turbine rotor.
9. An integrated bucket wheel for a rotor component of a reaction
turbine comprising a unitary 360.degree. piece of stock material
having a radially outer portion machined to include a plurality of
buckets, each having an airfoil portion and a radially outer tip
shroud portion; and a radially inner portion machined to include a
plurality of tie-rod or bolt holes circumferentially spaced about
said radially inner portions.
10. The integrated bucket wheel of claim 9 wherein said stock
material comprises a forged stock.
11. The integrated bucket wheel of claim 9 wherein said stock
material comprises rolled ring stock.
12. The integrated bucket wheel of claim 9 wherein said stock
material comprises generally flat plate stock.
13. A method of making a turbine bucket wheel comprising forming
flat stock material into an annular ring; machining a radially
outer portion of said annular ring to include a plurality of
buckets, each comprising an airfoil portion, and machining a
radially inner portion of said annular ring to include assembly
features.
14. The method of claim 13 wherein said assembly features include a
center opening and a plurality of circumferentially spaced tie-rod
or bolt holes.
15. The method of claim 13 including machining a 360.degree. shroud
cover on radially outer tips of said airfoil portions.
16. The method of claim 13 wherein said stock material comprises a
forged stock.
17. The method of claim 13 wherein said stock material comprises
rolled ring stock.
18. The method of claim 13 wherein said stock material comprises
generally flat plate stock.
Description
[0001] This application is a continuation-in-part of application
Ser. No. ______ (Attorney Dkt. No. 839-1738), entitled, "INTEGRATED
NOZZLE WHEEL FOR REACTION STEAM TURBINE STATIONARY COMPONENTS AND
RELATED METHOD," filed on Sep. 7, 2005.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to steam turbine
construction and, more specifically, to integrated nozzle and
bucket wheel constructions for a reaction steam turbine.
[0003] Current integral-cover reaction nozzle stages are made up of
large quantities of individual reaction nozzles that are assembled
into a machined stator casting or nozzle carrier. More
specifically, individual nozzles are loaded into a dovetail groove
and secured within the carrier using individual radial loading
pins. Each nozzle tip is machined with a specified tip seal
configuration for interaction with the turbine rotor so as to
minimize leakage along the hot gas path.
[0004] Similarly, current integral-cover reaction bucket stages are
also made up of large quantities of individual reaction buckets,
assembled into a machined rotor forging using individual radial
loading pins. After assembly, the buckets are secured with
retention hardware, the bucket tips are machined to the specified
tip seal configuration.
[0005] The time and cost associated with the manufacture of the
stator casting, stator machining, nozzle stock material and nozzle
machining, and stator assembly, as well as the rotor forging, rotor
machining, bucket stock material, bucket machining and assembly add
significant costs overall to the reaction steam path.
BRIEF DESCRIPTION OF THE INVENTION
[0006] In accordance with an exemplary embodiment of this
invention, the nozzle and bucket manufacturing/assembly processes
are simplified, and the overall cost of the reaction steam path is
reduced without impacting the integrity of the overall reaction
steam turbine design.
[0007] In the exemplary embodiment, a full row of reaction nozzles
is machined into a 360.degree. piece of flat stock material. It
will be understood that the stock material may be forged, rolled
ring or plate stock. The 360.degree. ring is placed into a
machining center where the ID, OD, inlet blends, airfoils, airfoil
radii, cover shroud sealing configuration, retention features and
the balance of the standard nozzle features are machined.
Thereafter, the integrated nozzle wheel may or may not be split
into two or more arcuate segments in preparation for the final
steam path assembly process.
[0008] Similarly, a single stage of reaction airfoils may be
machined into a 360.degree. piece of flat stock material that also
may be forged, rolled ring or plate stock. The bucket seal tip
geometry, mating axial face rabbet fits and retention features may
also be machined into the integrated bucket wheel.
[0009] It is also possible to incorporate into the integrated
nozzle and bucket wheels, adjacent stator and rotor surfaces, that
are forward and/or aft of the nozzle and/or bucket airfoils,
respectively, and utilized to facilitate axial stacking of plural
nozzle wheels in an alternating arrangement with respective bucket
wheels.
[0010] Accordingly, in one aspect, the present invention relates to
an integrated bucket wheel for a turbine rotor component comprising
a three hundred sixty degree wheel formed from a single piece of
stock material, a radially outer portion of the wheel manufactured
to include a plurality of buckets, each having an airfoil portion
and a radially outer tip shroud portion; and a radially inner
portion of the bucket wheel manufactured to include one or more
assembly features.
[0011] In another aspect, the invention relates to an integrated
bucket wheel for a rotor component of a reaction turbine comprising
a unitary 360.degree. piece of stock material having a radially
outer portion machined to include a plurality of buckets, each
having an airfoil portion and a radially outer tip shroud portion;
and a radially inner portion machined to include a plurality of
tie-rod or bolt holes circumferentially spaced about the radially
inner portions.
[0012] In still another aspect, the invention relates to a method
of making a turbine bucket wheel comprising forming flat stock
material into an annular ring; machining a radially outer portion
of the annular ring to include a plurality of buckets, each
comprising an airfoil portion, and machining a radially inner
portion of the annular ring to include assembly features.
[0013] The invention will now be described in detail in connection
with the drawings identified below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view of an integrated nozzle wheel
in accordance with an exemplary embodiment of the invention;
[0015] FIG. 2 is a perspective view of another integrated nozzle
wheel in accordance with the invention;
[0016] FIG. 3 is a perspective view of the nozzle wheel of FIG. 1
assembled in a lower turbine casing component;
[0017] FIG. 4 is a perspective view similar to FIG. 3, but with an
upper turbine casing component located over the upper nozzle wheel
segment; and
[0018] FIG. 5 is a perspective view of an integrated turbine rotor
bucket wheel in accordance with another embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] With initial reference to FIG. 1, an integrated nozzle wheel
10 is shown, split into upper and lower 180.degree. segments or
halves 12, 14. It will be appreciated that splitting the wheel
facilitates assembly in the upper and lower turbine casing
components or sections, with the nozzle wheel segments surrounding
the rotor.
[0020] In the exemplary embodiment, the wheel 10 is manufactured
from a single 360.degree. piece of flat stock material that could
be forged, rolled ring or plate stock. The annular ring is
thereafter machined to include a plurality of airfoils 16, in a
circumferential array at the radially inner portion of the wheel.
The radially inner ends of the airfoils 16 are also machined to
include an integral cover shroud sealing configuration 18 that
determines the ID of the wheel. The remainder of the wheel,
specifically the radially outer portion 20, is formed to include
assembly bolt or tie-rod holes 22 and any other rim or rabbet
configuration to facilitate axial stacking with similar wheels, or
with discrete spacer rings therebetween that accommodate the
rotating stages on the rotor.
[0021] FIG. 2 illustrates another integrated nozzle wheel 24 where
one side 26 of the wheel is machined to include a blended
toroidal-shaped inlet 28 extending axially upstream of the
integrated nozzles 30. Here again, bolt or tie-rod holes 32 are
provided in the radially outer region 34 to facilitate axial
stacking.
[0022] FIG. 3 illustrates the nozzle wheel 10 of FIG. 1 located in
a lower turbine casing component 36 with a plurality of tie rods or
bolts 38 extending through the holes 22 and secured by nuts 40 or
the like to facilitate axial stacking of multiple nozzle
wheels.
[0023] FIG. 4 illustrates the arrangement in FIG. 3 but with an
upper casing component 42 assembled over the lower casing component
32. It will be appreciated that the upper and lower nozzle wheel
segments 12, 14 and the upper and lower casing components 36, 42
will be secured, respectively, to each other, using conventional
retention/securement hardware configurations (not shown). In the
case of the nozzle wheel segments, the retention/securement
features will be machined into the segments consistent with the
invention described herein.
[0024] Turning to FIG. 5, a reaction turbine rotor bucket wheel 44
is formed from a single, circular flat plate of stock material
(forged, rolled ring or plate stock). The wheel 44 is formed with a
center bore 46, a radially inner portion 48 and a radially outer
portion 50. It will be appreciated that the bore 46 may be machined
to the desired geometry, depending on the associated rotor size,
configuration, etc.
[0025] The radially inner portion 48 is provided with fastening
features which, in the example illustrated, includes a plurality of
bolt or tie-rod holes 52 circumferentially spaced about the
radially inner portion. The radially outer portion 50 is machined
to include a plurality of buckets 54, each including an airfoil
portion 56 and an integral shroud or tip cover 58 that extends
360.degree. , over all of the radially outer tips of the air foil
portions 56.
[0026] As in the case of the turbine nozzle wheel shown in FIG. 1,
the bucket wheel 44 may be split into a pair of 180.degree. arcuate
segments to facilitate assembly, particularly for field replacement
of a single wheel. In other instances, the bucket wheel 44 may
remain, and be assembled as a unitary, integrated, 360.degree.
bucket wheel.
[0027] In addition to the airfoil portion 56 and shroud or tip
cover 58, the machining operation may also include finish machining
of the wheel OD, ID, inlet blends, airfoil radii and any other
standard bucket features.
[0028] Adjacent rotor surfaces that are forwarded and aft of the
bucket airfoil portions, may also be integrated into the bucket
wheel. For example, a single adjacent rotor surface (forward or
aft) may be incorporated into the bucket wheel, and may be integral
or added on after the air foils have been machined. Alternatively,
double adjacent rotor surfaces (forward and aft) may be
incorporated into the bucket wheel and may be integral or added on
after the airfoils have been machined. Some applications may not
require any added adjacent rotor surfaces.
[0029] By machining the airfoils in the fashion disclosed
hereinabove, the following obstacles associated with current
reaction bucket design may be eliminated: [0030] Cover shroud
interference; [0031] Untwist of cover shrouds during operation;
[0032] Axial clearance issues related to the untwist for assembling
multiple individual bucket/pins for each stage. [0033] The need to
perform in process assembly checks such as twist, shingling and
throat area measurements; [0034] The need for standing assembled
modal test and the associated costs of each test; and [0035]
Ergonomic concerns related to assembling individual loading pins
for individual buckets.
[0036] In addition to eliminating the items above, the integrated
bucket wheel may also accomplish the following: [0037] Increase the
ability to service/repair rows of buckets; [0038] Create a
known/repeatable boundary condition; [0039] Reduce the number of
parts per stage; [0040] Reduce the amount of variation within an
assembled stage; [0041] Reduce the amount of unused (wasted)
material from the bucket and rotor manufacturing processes; [0042]
Reduce the size, weight and cost of the rotor forging; [0043]
Prevent assembly in the wrong location and/or direction; [0044]
Reduce the number of resources needed to support
manufacturing-fewer manufacturing processes, fixtures, operators,
inspections, program and attendant opportunities for errors; and
[0045] Significantly reduce the amount of material required versus
individual parts.
[0046] 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.
* * * * *