EP1722070A2 - Method of manufacturing segmented stators for a steam turbine - Google Patents
Method of manufacturing segmented stators for a steam turbine Download PDFInfo
- Publication number
- EP1722070A2 EP1722070A2 EP06252184A EP06252184A EP1722070A2 EP 1722070 A2 EP1722070 A2 EP 1722070A2 EP 06252184 A EP06252184 A EP 06252184A EP 06252184 A EP06252184 A EP 06252184A EP 1722070 A2 EP1722070 A2 EP 1722070A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- segments
- flat plate
- plate stock
- nozzle
- airfoils
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
- F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
- F01D9/041—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector using blades
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D9/00—Stators
- F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
- F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
Definitions
- This invention relates to a method of producing steam turbine components and, specifically, dovetailed reaction nozzle segments.
- a plurality of nozzles are manufactured by machining from a single piece of flat plate stock.
- a single solid donut-shaped ring is cut from flat plate stock and then cut into two 180° segments.
- the cut ends of the segments may then be configured for temporary attachment to a machining jig or the like, or the segments may be temporarily joined together (by, e.g., bolts) on a jig and subsequently machined to include integral shroud covers, airfoils and dovetails.
- the two 180° segments are loaded into the nozzle carrier or casing dovetail in the usual manner.
- four 90° segments may be cut from the solid ring and subsequently machined to each include 25% of the required nozzles.
- arcuately shorter segments may be machined to include as few as two integral nozzle airfoils, thus still reducing the nozzle components by half.
- the invention relates to a method of manufacturing reaction nozzles for a turbine comprising (a) providing a piece of flat plate stock of predetermined size and thickness; and (b) machining the piece of flat plate stock to form a unitary, arcuate reaction nozzle segment including at least two adjacent nozzle airfoils.
- the invention in another aspect, relates to a method of manufacturing reaction nozzles for a turbine comprising (a) providing a single piece of flat plate stock of predetermined size and thickness; and (b) cutting the flat plate stock to form a 360° ring; (c) cutting the 360° ring into two or more arcuate segments; and (d) machining each of the segments to include a plurality of nozzle airfoils.
- the invention relates to a reaction nozzle component for a steam turbine comprising a unitary arcuate segment formed to include a plurality of adjacent nozzle airfoils.
- a conventional steam turbine reaction nozzle 10 includes an airfoil 12 and an integral radially inner tip shroud or cover 14.
- the radially outer end of the nozzle is formed with a base 16 having a dovetail configuration.
- the base or dovetail 16 is provided with a pair of flanges 18 and 20 projecting in both axially upstream and downstream directions, defining recesses 22 therebetween.
- the nozzle casing or carrier (not shown) is provided with generally correspondingly shaped dovetail grooves which allow the nozzles 10 to be individually loaded into the carrier or casing at a conventional notched cut-out.
- each nozzle can be loaded into the dovetail slot in the carrier until the entire row of nozzles has been assembled.
- the dovetail arrangement may be reversed, with the dovetail groove component formed in the nozzle and the dovetail hook component formed on the carrier or casing.
- Figure 2 illustrates a unitary arcuate dovetail reaction nozzle component or segment manufactured in accordance with an exemplary embodiment of the invention.
- the segment 24 is machined from a single piece of flat metal plate stock and includes a plurality of adjacent airfoil portions (or simply “airfoils") 26 with an integral, common tip shroud or cover 28 at the radially inner ends of the airfoils, and an integral, common dovetail hook 30 at the radially inner ends of the airfoils.
- the arcuate length of the segments may be varied as desired to include as few as two airfoils or as many as 50% of the airfoils required for a full 360° reaction nozzle ring.
- the common dovetail comprises a centerline support mechanism for a 180° segment.
- the segments 38 and 40 are then machined to include the airfoils 26, integral tip shrouds or tip covers 28, and dovetail hooks 30 as shown in Figure 2, but noting that Figure 2 illustrates an arcuately shorter segment. After machining, the segments 38 and 40 are disassembled or removed from the jig and are ready for insertion into the carrier or casing dovetail groove.
- a solid ring 48 may be cut from the flat plate stock into four individual 90° segments 50, 52, 54 and 56 and machined to each include 25% of the required airfoils.
- the arcuate length of the airfoil segments may be altered as desired with each segment including at least two airfoils.
- the flat plate stock 38 may be high grade 400 Series stainless steel with 12% chromium, or other suitable material.
- shims of appropriate thickness may be placed between the segments at the dovetail.
- the segments may be held in place in the dovetail via conventional radial end or axial shims which eliminate the radial end or axial gap between the segment dovetail and the dovetail groove in the casing or carrier.
- machined segment concept in accordance with aspects of this invention also improves the ability to service/repair rows relative to current practice; creates a known/repeatable/unvarying boundary condition; reduces the number of parts per stage; and insures that segments are assembled in the correct location/direction.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Turbine Rotor Nozzle Sealing (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Description
- This invention relates to a method of producing steam turbine components and, specifically, dovetailed reaction nozzle segments.
- Current fixed reaction nozzle stages that are located between rotating turbine stages (or wheels) are made up of individual nozzles that are individually inserted within a dovetail slot in a fixed nozzle carrier or turbine casing. The nozzles are formed with integral dovetails at their radially outer ends and integral tip shrouds at their radially inner ends. These nozzles are designed to maintain tip shroud contact throughout operation by incorporating appropriate cover or tip shroud interference along with a pre-twisted cold airfoil portions. During assembly of such nozzles, it has been difficult to confirm that the required cover or tip shroud interference has been obtained. In addition, the process of pre-twisting the nozzle airfoils at assembly causes the airfoils to deviate from the "design" airfoil shape. This can potentially reduce the efficiency of the airfoil.
- Various embodiments of the present invention substantially eliminate many issues relating to individually formed nozzle airfoils. In accordance with an exemplary embodiment, a plurality of nozzles are manufactured by machining from a single piece of flat plate stock. For example, in one exemplary embodiment, a single solid donut-shaped ring is cut from flat plate stock and then cut into two 180° segments. The cut ends of the segments may then be configured for temporary attachment to a machining jig or the like, or the segments may be temporarily joined together (by, e.g., bolts) on a jig and subsequently machined to include integral shroud covers, airfoils and dovetails. After machining, the two 180° segments are loaded into the nozzle carrier or casing dovetail in the usual manner.
- In another arrangement, four 90° segments may be cut from the solid ring and subsequently machined to each include 25% of the required nozzles.
- Alternatively, arcuately shorter segments may be machined to include as few as two integral nozzle airfoils, thus still reducing the nozzle components by half.
- In all cases, proper spacing between arcuate nozzle segments can be maintained through the utilization of shims of appropriate thickness placed between the segments and the carrier or casing dovetail.
- Accordingly, in one aspect, the invention relates to a method of manufacturing reaction nozzles for a turbine comprising (a) providing a piece of flat plate stock of predetermined size and thickness; and (b) machining the piece of flat plate stock to form a unitary, arcuate reaction nozzle segment including at least two adjacent nozzle airfoils.
- In another aspect, the invention relates to a method of manufacturing reaction nozzles for a turbine comprising (a) providing a single piece of flat plate stock of predetermined size and thickness; and (b) cutting the flat plate stock to form a 360° ring; (c) cutting the 360° ring into two or more arcuate segments; and (d) machining each of the segments to include a plurality of nozzle airfoils.
- In still another aspect, the invention relates to a reaction nozzle component for a steam turbine comprising a unitary arcuate segment formed to include a plurality of adjacent nozzle airfoils.
- The invention will now be described in connection with the drawings identified below, in which:
- FIGURE 1 is a perspective view of a known steam turbine reaction nozzle;
- FIGURE 2 is a perspective view of a unitary arcuate reaction nozzle segment in accordance with an exemplary embodiment of this invention;
- FIGURE 3 is a plan view of a piece of flat plate stock marked for cutting a 360° ring from the stock;
- FIGURE 4 is a plan view of the ring removed from the plate stock of Figure 3 and cut to form two 180° arcuate segments;
- FIGURE 5 is an exploded view of the two 180° arcuate segments of Figure 4 modified for temporary attachment to a jig or to each other for machining; and
- FIGURE 6 is a plan view of a solid ring cut into four 90° segments for subsequent machining in accordance with another embodiment of the invention.
- With reference initially to Figure 1, a conventional steam
turbine reaction nozzle 10 includes anairfoil 12 and an integral radially inner tip shroud orcover 14. The radially outer end of the nozzle is formed with abase 16 having a dovetail configuration. Specifically, the base ordovetail 16 is provided with a pair offlanges recesses 22 therebetween. It will be appreciated that the nozzle casing or carrier (not shown) is provided with generally correspondingly shaped dovetail grooves which allow thenozzles 10 to be individually loaded into the carrier or casing at a conventional notched cut-out. Thus, each nozzle can be loaded into the dovetail slot in the carrier until the entire row of nozzles has been assembled. It will also be appreciated that the dovetail arrangement may be reversed, with the dovetail groove component formed in the nozzle and the dovetail hook component formed on the carrier or casing. - Figure 2 illustrates a unitary arcuate dovetail reaction nozzle component or segment manufactured in accordance with an exemplary embodiment of the invention. The
segment 24 is machined from a single piece of flat metal plate stock and includes a plurality of adjacent airfoil portions (or simply "airfoils") 26 with an integral, common tip shroud orcover 28 at the radially inner ends of the airfoils, and an integral,common dovetail hook 30 at the radially inner ends of the airfoils. As will be described further below, the arcuate length of the segments may be varied as desired to include as few as two airfoils or as many as 50% of the airfoils required for a full 360° reaction nozzle ring. In one embodiment, the common dovetail comprises a centerline support mechanism for a 180° segment. - Turning to Figure 3, a donut-
shaped ring 36 is initially cut from a single piece offlat plate stock 38, using any conventional cutting technique, for example, wire electrical discharge machining (EDM). With thering 36 removed from the plate stock as shown in Figure 4, the ring is cut into two 180°segments separated segments segments segments airfoils 26, integral tip shrouds or tip covers 28, anddovetail hooks 30 as shown in Figure 2, but noting that Figure 2 illustrates an arcuately shorter segment. After machining, thesegments - In an alternative arrangement as shown in Figure 6, a
solid ring 48 may be cut from the flat plate stock into four individual 90°segments - In the exemplary embodiment, the
flat plate stock 38 may be high grade 400 Series stainless steel with 12% chromium, or other suitable material. - In order to maintain proper circumferential spacing of the airfoils, shims of appropriate thickness may be placed between the segments at the dovetail. The segments may be held in place in the dovetail via conventional radial end or axial shims which eliminate the radial end or axial gap between the segment dovetail and the dovetail groove in the casing or carrier.
- By machining airfoils in this fashion, a number of issues associated with the current individual reaction nozzle design can be substantially eliminated or at least minimized including:
- tip shroud interference and associated manufacturing and assembly difficulties;
- untwist of shrouds and airfoils during operation;
- axial clearance issues related to the piece-part twist variation at assembly and during operation;
- assembling individual nozzle/pins for each stage;
- the need to perform in-process assembly checks such as twist, shingling and throat area measurements;
- the need for standing assembled modal tests and associated costs and scheduling impacts of each test;
- ergonomic concerns related to assembling individual loading pins for individual nozzles.
- In addition to eliminating the issues above, the machined segment concept in accordance with aspects of this invention also improves the ability to service/repair rows relative to current practice; creates a known/repeatable/unvarying boundary condition; reduces the number of parts per stage; and insures that segments are assembled in the correct location/direction.
- 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.
Claims (10)
- A method of manufacturing reaction nozzles for a turbine comprising:(a) providing a piece of flat plate stock (38) of predetermined size and thickness; and(b) machining said piece of flat plate stock (38) to form a unitary, arcuate reaction nozzle segment (24) including at least two adjacent nozzle airfoils (26).
- The method of claim 1 wherein said reaction nozzle segment (24) also includes a common tip shroud cover (28) and a common dovetail hook (30) at opposite ends of, and spanning, said at least two adjacent nozzle airfoils (26).
- The method of claim 1 or claim 2 wherein said flat plate stock (38) is comprised of a stainless steel alloy.
- The method of claim 3 wherein said stainless steel alloy comprises a 400 Series stainless steel with 12% chromium.
- The method of any preceding claim wherein each of said arcuate segments (24) spans substantially 180°.
- The method of any one of claims 1 to 4 wherein each of said arcuate segments (24) spans substantially 90°.
- A method of manufacturing reaction nozzles for a turbine comprising:(a) providing a single piece of flat plate stock (38) of predetermined size and thickness; and(b) cutting said flat plate stock (38) to form a 360° ring (36);(c) cutting said 360° ring (36) into two or more arcuate segments (40, 42); and(d) machining each of said segments to include a plurality of nozzle airfoils (26).
- The method of claim 7 wherein, during step (d), each segment also includes an integral, common tip shroud cover (28) and an integral, common dovetail component (30).
- The method of claim 7 or claim 8 wherein steps (b) and (c) are carried out with wire EDM.
- The method of any one of claims 7 to 9 wherein, during step (c), said ring is cut into four 90° segments (50, 52, 54, 56).
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/115,371 US20060245923A1 (en) | 2005-04-27 | 2005-04-27 | Arcuate nozzle segment and related method of manufacture |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1722070A2 true EP1722070A2 (en) | 2006-11-15 |
EP1722070A3 EP1722070A3 (en) | 2011-10-12 |
Family
ID=36994715
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP06252184A Withdrawn EP1722070A3 (en) | 2005-04-27 | 2006-04-22 | Method of manufacturing segmented stators for a steam turbine |
Country Status (4)
Country | Link |
---|---|
US (1) | US20060245923A1 (en) |
EP (1) | EP1722070A3 (en) |
CN (1) | CN1880731B (en) |
RU (1) | RU2006114341A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1764482A2 (en) * | 2005-09-07 | 2007-03-21 | General Electric Company | Single piece nozzle wheel and manufacturing method |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070071605A1 (en) * | 2005-09-23 | 2007-03-29 | General Electric Company | Integrated nozzle and bucket wheels for reaction steam turbine stationary components and related method |
EP2735707B1 (en) * | 2012-11-27 | 2017-04-05 | Safran Aero Boosters SA | Axial turbomachine guide nozzle with segmented inner shroud and corresponding compressor |
EP3967846B1 (en) | 2020-09-10 | 2024-04-03 | General Electric Technology GmbH | Nozzle segment, steam turbine with diaphragm of multiple nozzle segments and method for assembly thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6425738B1 (en) * | 2000-05-11 | 2002-07-30 | General Electric Company | Accordion nozzle |
EP1764482A2 (en) * | 2005-09-07 | 2007-03-21 | General Electric Company | Single piece nozzle wheel and manufacturing method |
EP1785594A2 (en) * | 2005-11-11 | 2007-05-16 | General Electric Company | Stacked reaction steam turbine stator assembly |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3091383A (en) * | 1957-02-14 | 1963-05-28 | Stalker Corp | Bladed rotor for fluid machines |
US3056583A (en) * | 1960-11-10 | 1962-10-02 | Gen Electric | Retaining means for turbine shrouds and nozzle diaphragms of turbine engines |
US3302926A (en) * | 1965-12-06 | 1967-02-07 | Gen Electric | Segmented nozzle diaphragm for high temperature turbine |
SE463702B (en) * | 1989-06-01 | 1991-01-14 | Abb Stal Ab | SET TO MAKE A SHARED CIRCULAR RING |
US5174715A (en) * | 1990-12-13 | 1992-12-29 | General Electric Company | Turbine nozzle |
US5438755A (en) * | 1993-11-17 | 1995-08-08 | Giberson; Melbourne F. | Method of making a monolithic shrouded impeller |
US6183192B1 (en) * | 1999-03-22 | 2001-02-06 | General Electric Company | Durable turbine nozzle |
GB9922248D0 (en) * | 1999-09-21 | 1999-11-17 | Rolls Royce Plc | Improvements in or relating to methods and apparatus for machining workpieces |
JP4040922B2 (en) * | 2001-07-19 | 2008-01-30 | 株式会社東芝 | Assembly type nozzle diaphragm and its assembly method |
CA2366325A1 (en) * | 2001-12-27 | 2003-06-27 | Todd Howley | Method of forming turbine blade root |
US6722848B1 (en) * | 2002-10-31 | 2004-04-20 | General Electric Company | Turbine nozzle retention apparatus at the carrier horizontal joint face |
FR2873940B1 (en) * | 2004-08-03 | 2008-01-04 | Snecma Moteurs Sa | METHOD FOR MANUFACTURING CONSTITUENT PIECES OF A HOLLOW DRAW BY ROLLING |
US20070071605A1 (en) * | 2005-09-23 | 2007-03-29 | General Electric Company | Integrated nozzle and bucket wheels for reaction steam turbine stationary components and related method |
-
2005
- 2005-04-27 US US11/115,371 patent/US20060245923A1/en not_active Abandoned
-
2006
- 2006-04-22 EP EP06252184A patent/EP1722070A3/en not_active Withdrawn
- 2006-04-26 RU RU2006114341/06A patent/RU2006114341A/en not_active Application Discontinuation
- 2006-04-27 CN CN2006100771495A patent/CN1880731B/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6425738B1 (en) * | 2000-05-11 | 2002-07-30 | General Electric Company | Accordion nozzle |
EP1764482A2 (en) * | 2005-09-07 | 2007-03-21 | General Electric Company | Single piece nozzle wheel and manufacturing method |
EP1785594A2 (en) * | 2005-11-11 | 2007-05-16 | General Electric Company | Stacked reaction steam turbine stator assembly |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1764482A2 (en) * | 2005-09-07 | 2007-03-21 | General Electric Company | Single piece nozzle wheel and manufacturing method |
EP1764482A3 (en) * | 2005-09-07 | 2010-05-05 | General Electric Company | Single piece nozzle wheel and manufacturing method |
Also Published As
Publication number | Publication date |
---|---|
EP1722070A3 (en) | 2011-10-12 |
CN1880731B (en) | 2010-05-12 |
RU2006114341A (en) | 2007-11-10 |
CN1880731A (en) | 2006-12-20 |
US20060245923A1 (en) | 2006-11-02 |
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