EP1772595A2 - Steam turbine exhaust diffuser - Google Patents
Steam turbine exhaust diffuser Download PDFInfo
- Publication number
- EP1772595A2 EP1772595A2 EP06255126A EP06255126A EP1772595A2 EP 1772595 A2 EP1772595 A2 EP 1772595A2 EP 06255126 A EP06255126 A EP 06255126A EP 06255126 A EP06255126 A EP 06255126A EP 1772595 A2 EP1772595 A2 EP 1772595A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- steam
- volute
- flow path
- exhaust
- turbine
- 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- Withdrawn
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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
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/30—Exhaust heads, chambers, or the like
-
- 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
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/28—Supporting or mounting arrangements, e.g. for turbine casing
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- F05D2220/00—Application
- F05D2220/30—Application in turbines
- F05D2220/31—Application in turbines in steam turbines
Definitions
- the present invention relates to steam turbines and particularly relates to an exhaust diffuser in the shape of a volute.
- the inner case of the steam turbine for example a double flow down exhaust unit has an encompassing exhaust hood split vertically and extending along opposite sides and ends of the turbine.
- This large box-like structure houses the entire low pressure section of the turbine.
- the exhaust steam outlet from the turbine is generally conically shaped and the steam exhaust is redirected from a generally axial extending flow direction to a flow direction 90° relative to the axial flow direction.
- This 90° flow direction may be in any plane, downwardly, upwardly or transversely.
- the prior exhaust hoods for steam turbines constitute a large rectilinear structure at the exit end of the conical section for turning and diffusing the steam flow at right angles. The steam flow path was thus tortuous resulting in losses and adverse pressure drop.
- an axial flow steam turbine flow path comprising: a rotor and a casing defining the axial steam flow path; and an exhaust diffuser for the turbine including a volute for diffusing the exhaust steam and turning the exhaust steam from a generally axial flow direction to a generally transverse and tangential direction.
- FIG. 1 there is illustrated a portion of a steam turbine, generally designated 10, including a rotor 12 mounting a plurality of turbine buckets 14.
- An inner casing 16 is also illustrated mounting a plurality of diaphragms 18.
- a centrally disposed generally radial steam inlet 20 applies steam to each of the turbine buckets and stator blades on opposite axial sides of the turbine to drive the rotor.
- the stator vanes of the diaphragms 18 and the axially adjacent buckets 14 form the various stages of the turbine forming a flow path and it will be appreciated that the steam is exhausted from the final stage of the turbine for flow into a condenser not shown.
- an outer exhaust hood 22 which surrounds and supports the inner casing of the turbine as well as other parts such as the bearings.
- the turbine includes steam guides 24 for guiding the steam exhausting from the turbine into an outlet 26 for flow to one or more condensers.
- FIG. 2 there is illustrated an aspect of the present invention wherein like reference numerals as in Figure 1 are applied to like parts preceded by the numeral 1.
- the diffuser 40 includes a diffusing conical section 42 coupled to the inner casing 116 by a flexible joint 44.
- the volute 40 has an axis parallel to the axis of rotation of the rotor 112.
- the axis of volute 40 is generally perpendicular to the direction of the general spiral flow about the axis and through the volute. Consequently, the exhaust steam flowing substantially in an axial direction from the final stage of the turbine flows into the volute 40 where it changes its flow direction by about 90°.
- the volute 40 By using the volute 40, the geometry of the volute enables the steam to expand reducing its pressure.
- the volute 40 also guides the diffused steam through an outlet 46 coupled to one or more condensers, not shown.
- the volute 40 includes an internal passage 48 which increases in cross-sectional area in a direction toward the outlet 46 thereby diffusing the exhaust steam.
- the exit or outlet 46 need not be a down exhaust but can be a side or upwardly directed exhaust.
- a single volute can exhaust a single flow steam turbine or a pair of volutes may exhaust steam from double flow steam turbines.
- a double walled volute is illustrated having a divider wall 50 forming a pair of diffuser exit passages.
- the flexible connection may be of many different types such as an expansion bellows to allow for differential thermal expansion.
- the previously utilized exhaust hood is no longer necessary for the support of the turbine bearings.
- the bearings 54 may be supported on stanchions 56 in turn directly supported by the foundation of the turbine.
- the stanchions provide a rigid support for the bearings with improved turbine reliability as a result.
- the volute may be formed of a composite material, steel plate or pipe, structural steel, fiber-reinforced plastic or any combination of these materials to obtain the required structural integrity and desired steam flow diffusion characteristics.
Abstract
Description
- The present invention relates to steam turbines and particularly relates to an exhaust diffuser in the shape of a volute.
- In prior steam turbines, the inner case of the steam turbine, for example a double flow down exhaust unit has an encompassing exhaust hood split vertically and extending along opposite sides and ends of the turbine. This large box-like structure houses the entire low pressure section of the turbine. The exhaust steam outlet from the turbine is generally conically shaped and the steam exhaust is redirected from a generally axial extending flow direction to a flow direction 90° relative to the axial flow direction. This 90° flow direction may be in any plane, downwardly, upwardly or transversely. Thus the prior exhaust hoods for steam turbines constitute a large rectilinear structure at the exit end of the conical section for turning and diffusing the steam flow at right angles. The steam flow path was thus tortuous resulting in losses and adverse pressure drop. It will also be appreciated that access to various parts of the turbine, for example, the bearing for maintenance purposes was difficult in that it necessitated the removal of the upper half of the exhaust hood. Further, it will be appreciated that the exhaust hood in conventional steam turbines typically supports the inner casing of the turbine and the associated steam path parts such as diaphragms and the like. Accordingly, there has been found a need to provide a new geometry to improve exhaust steam pressure recovery and overall performance of the turbine.
- In a preferred embodiment of the invention, there is provided an axial flow steam turbine flow path comprising: a rotor and a casing defining the axial steam flow path; and an exhaust diffuser for the turbine including a volute for diffusing the exhaust steam and turning the exhaust steam from a generally axial flow direction to a generally transverse and tangential direction.
- Embodiments of the present invention are described, by way of example only, with reference to the accompanying drawings, in which:
- FIGURE 1 is a fragmentary schematic illustration of half of a double flow down exhaust steam turbine according to the prior art.
- FIGURE 2 is a fragmentary side cross-sectional view of a steam turbine illustrating an exhaust diffuser having a volute configuration; and
- FIGURES 3 and 4 are axial end views of two embodiments of volutes which may be employed to receive the exhaust steam from the steam turbine.
- Referring now to the drawings, particularly to Figure 1 there is illustrated a portion of a steam turbine, generally designated 10, including a
rotor 12 mounting a plurality ofturbine buckets 14. Aninner casing 16 is also illustrated mounting a plurality ofdiaphragms 18. A centrally disposed generallyradial steam inlet 20 applies steam to each of the turbine buckets and stator blades on opposite axial sides of the turbine to drive the rotor. The stator vanes of thediaphragms 18 and the axiallyadjacent buckets 14 form the various stages of the turbine forming a flow path and it will be appreciated that the steam is exhausted from the final stage of the turbine for flow into a condenser not shown. - Also illustrated in Figure 1 is an
outer exhaust hood 22 which surrounds and supports the inner casing of the turbine as well as other parts such as the bearings. In the illustration of Figure 1, the turbine includessteam guides 24 for guiding the steam exhausting from the turbine into anoutlet 26 for flow to one or more condensers. With the use of an exhaust hood supporting the turbine, bearings and ancillary parts, the exhaust steam path is tortuous and subject to pressure losses with consequent reduction in performance and efficiency. - Referring now to Figure 2, there is illustrated an aspect of the present invention wherein like reference numerals as in Figure 1 are applied to like parts preceded by the numeral 1. As illustrated, the
exhaust hood 22 of the prior art is completely eliminated in favor of avolute diffuser 40. Thediffuser 40 includes a diffusingconical section 42 coupled to theinner casing 116 by aflexible joint 44. Thevolute 40 has an axis parallel to the axis of rotation of therotor 112. The axis ofvolute 40 is generally perpendicular to the direction of the general spiral flow about the axis and through the volute. Consequently, the exhaust steam flowing substantially in an axial direction from the final stage of the turbine flows into thevolute 40 where it changes its flow direction by about 90°. Additionally, by using thevolute 40, the geometry of the volute enables the steam to expand reducing its pressure. Thevolute 40 also guides the diffused steam through anoutlet 46 coupled to one or more condensers, not shown. As illustrated in Figure 3, thevolute 40 includes aninternal passage 48 which increases in cross-sectional area in a direction toward theoutlet 46 thereby diffusing the exhaust steam. It will be appreciated that the exit oroutlet 46 need not be a down exhaust but can be a side or upwardly directed exhaust. In either configuration, a single volute can exhaust a single flow steam turbine or a pair of volutes may exhaust steam from double flow steam turbines. In Figure 4, a double walled volute is illustrated having adivider wall 50 forming a pair of diffuser exit passages. - Apart from the increased performance due to the diffusion of the steam in a volute on the steam exhaust side of the turbine, there are additional advantages. For example, the exhaust hood in prior conventional steam turbines is entirely eliminated and there is no longer a need to support the inner casing and associated steam path parts, such as diaphragms from the exhaust hood. Cost reduction is also realized because an exhaust hood is no longer used to enclose the inner casing. Also the overall dimensions of the turbine are reduced. Steam guides previously necessary are also entirely eliminated. Importantly, the inner casing and the volute of the turbine are each supported directly from the foundation of the turbine. To facilitate this, a flexible connection 44 (Figure 2) is provided between the inner casing and the
volute 40. The flexible connection may be of many different types such as an expansion bellows to allow for differential thermal expansion. Further, the previously utilized exhaust hood is no longer necessary for the support of the turbine bearings. As illustrated in Figure 2, thebearings 54 may be supported onstanchions 56 in turn directly supported by the foundation of the turbine. Thus, the stanchions provide a rigid support for the bearings with improved turbine reliability as a result. The volute may be formed of a composite material, steel plate or pipe, structural steel, fiber-reinforced plastic or any combination of these materials to obtain the required structural integrity and desired steam flow diffusion characteristics. - 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 (7)
- An axial flow steam turbine flow path comprising:a rotor (12) and a casing (16) defining the axial steam flow path; andan exhaust diffuser for the turbine including a volute (40) for diffusing the exhaust steam and turning the exhaust steam from a generally axial flow direction to a generally transverse and tangential direction.
- A flow path according to claim 1 wherein said volute (40) has an axis generally parallel to an axis of the flow path.
- A flow path according to claim 1 wherein said exhaust diffuser and said casing are independently mounted relative to one another on a foundation.
- A flow path according to claim 1 including a flexible joint (44) between said exhaust diffuser and said casing (16).
- A flow path according to claim 1 wherein said volute (40) has an axis generally parallel to an axis of the flow path, said volute terminating in an outlet (46) facing in a downward, upward or transverse direction.
- A flow path according to claim 1 wherein said volute (40) has an axis generally parallel to an axis of the flow path, said exhaust diffuser and said casing being independently mounted relative to one another on a foundation.
- A flow path according to claim 6 including a flexible joint (44) between said exhaust diffuser and said casing.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/243,974 US20070081892A1 (en) | 2005-10-06 | 2005-10-06 | Steam turbine exhaust diffuser |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1772595A2 true EP1772595A2 (en) | 2007-04-11 |
EP1772595A3 EP1772595A3 (en) | 2009-02-25 |
Family
ID=37395898
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP06255126A Withdrawn EP1772595A3 (en) | 2005-10-06 | 2006-10-04 | Steam turbine exhaust diffuser |
Country Status (4)
Country | Link |
---|---|
US (1) | US20070081892A1 (en) |
EP (1) | EP1772595A3 (en) |
JP (1) | JP2007100701A (en) |
CN (1) | CN1944962A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015156804A1 (en) * | 2014-04-10 | 2015-10-15 | Siemens Aktiengesellschaft | Gas turbine exhaust system |
Families Citing this family (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2415749B (en) * | 2004-07-02 | 2009-10-07 | Demag Delaval Ind Turbomachine | A gas turbine engine including an exhaust duct comprising a diffuser for diffusing the exhaust gas produced by the engine |
US20110176917A1 (en) * | 2004-07-02 | 2011-07-21 | Brian Haller | Exhaust Gas Diffuser Wall Contouring |
US7785068B2 (en) * | 2007-05-17 | 2010-08-31 | General Electric Company | Steam turbine exhaust hood and method of fabricating the same |
US20100162705A1 (en) * | 2008-12-30 | 2010-07-01 | Sharrow Edward J | Methods, systems and/or apparatus relating to steam turbine exhaust diffusers |
US8161749B2 (en) * | 2009-04-07 | 2012-04-24 | General Electric Company | Cooled exhaust hood plates for reduced exhaust loss |
US8221054B2 (en) * | 2009-05-28 | 2012-07-17 | General Electric Company | Corrugated hood for low pressure steam turbine |
US8221053B2 (en) * | 2009-05-28 | 2012-07-17 | General Electric Company | Shaped and stiffened lower exhaust hood sidewalls |
EP2295732A1 (en) * | 2009-09-14 | 2011-03-16 | Alstom Technology Ltd | Axial turbine and method for discharging a flow from an axial turbine |
US8662821B2 (en) | 2010-12-29 | 2014-03-04 | General Electric Company | Removable steam inlet assembly for steam turbine |
US8668450B2 (en) | 2010-12-29 | 2014-03-11 | General Electric Company | Removable upper steam guide segment for steam turbine |
CN102588016A (en) * | 2011-01-05 | 2012-07-18 | 南阳汉冶特钢有限公司 | Volute type symmetrical discharger |
RU111580U1 (en) * | 2011-02-11 | 2011-12-20 | Альстом Текнолоджи Лтд | OUTLET DEVICE FOR STEAM TURBINE MODULE |
US9057287B2 (en) * | 2011-08-30 | 2015-06-16 | General Electric Company | Butterfly plate for a steam turbine exhaust hood |
US9062568B2 (en) * | 2011-10-14 | 2015-06-23 | General Electric Company | Asymmetric butterfly plate for steam turbine exhaust hood |
CN102434233B (en) * | 2011-12-09 | 2014-05-28 | 青岛捷能汽轮机集团股份有限公司 | Exhaust steam cylinder of miniature steam turbine |
ITFI20120221A1 (en) * | 2012-10-22 | 2014-04-23 | Nuovo Pignone Srl | "EXHAUST GAS COLLECTOR AND GAS TURBINE" |
US20140119910A1 (en) * | 2012-10-29 | 2014-05-01 | General Electric Company | Turbine exhaust hood and related method |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB105933A (en) * | 1916-02-04 | 1917-05-04 | Karl Baumann | Improvements in or relating to Steam Turbines. |
US4390319A (en) * | 1979-09-25 | 1983-06-28 | Garkusha Anatoly V | Turbine exhaust hood |
US4961310A (en) * | 1989-07-03 | 1990-10-09 | General Electric Company | Single shaft combined cycle turbine |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1269998A (en) * | 1915-02-01 | 1918-06-18 | Westinghouse Electric & Mfg Co | Steam-turbine. |
US1814629A (en) * | 1928-10-12 | 1931-07-14 | Westinghouse Electric & Mfg Co | Elastic fluid turbine |
US1781108A (en) * | 1928-12-12 | 1930-11-11 | Worthington Pump & Mach Corp | Exhaust connection for condensers |
US2047501A (en) * | 1934-05-03 | 1936-07-14 | Spontan Ab | Steam or gas turbine |
US2781057A (en) * | 1953-03-06 | 1957-02-12 | Power Jets Res & Dev Ltd | Turbine outlet ducting |
US2840342A (en) * | 1953-03-17 | 1958-06-24 | David H Silvern | Turbine exhaust |
US5104286A (en) * | 1991-02-08 | 1992-04-14 | Westinghouse Electric Corp. | Recirculation seal for a gas turbine exhaust diffuser |
US6134876A (en) * | 1997-11-26 | 2000-10-24 | General Electric Company | Gas turbine engine with exhaust expander and compressor |
US6419448B1 (en) * | 2000-03-20 | 2002-07-16 | Jerzy A. Owczarek | Flow by-pass system for use in steam turbine exhaust hoods |
-
2005
- 2005-10-06 US US11/243,974 patent/US20070081892A1/en not_active Abandoned
-
2006
- 2006-09-30 CN CNA2006101420320A patent/CN1944962A/en active Pending
- 2006-10-04 EP EP06255126A patent/EP1772595A3/en not_active Withdrawn
- 2006-10-05 JP JP2006273597A patent/JP2007100701A/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB105933A (en) * | 1916-02-04 | 1917-05-04 | Karl Baumann | Improvements in or relating to Steam Turbines. |
US4390319A (en) * | 1979-09-25 | 1983-06-28 | Garkusha Anatoly V | Turbine exhaust hood |
US4961310A (en) * | 1989-07-03 | 1990-10-09 | General Electric Company | Single shaft combined cycle turbine |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015156804A1 (en) * | 2014-04-10 | 2015-10-15 | Siemens Aktiengesellschaft | Gas turbine exhaust system |
CN106460562A (en) * | 2014-04-10 | 2017-02-22 | 西门子公司 | Gas turbine exhaust system |
CN106460562B (en) * | 2014-04-10 | 2018-06-26 | 西门子公司 | Combustion turbine exhaustion system |
Also Published As
Publication number | Publication date |
---|---|
EP1772595A3 (en) | 2009-02-25 |
US20070081892A1 (en) | 2007-04-12 |
CN1944962A (en) | 2007-04-11 |
JP2007100701A (en) | 2007-04-19 |
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