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US3915588A - Two-shell axial-plane split casing structure for high-capacity low-pressure sections of a steam turbine - Google Patents

Two-shell axial-plane split casing structure for high-capacity low-pressure sections of a steam turbine Download PDF

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Publication number
US3915588A
US3915588A US503386A US50338674A US3915588A US 3915588 A US3915588 A US 3915588A US 503386 A US503386 A US 503386A US 50338674 A US50338674 A US 50338674A US 3915588 A US3915588 A US 3915588A
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US
United States
Prior art keywords
frustum
casing
inner casing
steam
shaped shells
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.)
Expired - Lifetime
Application number
US503386A
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English (en)
Inventor
Kurt Brandstatter
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BBC Brown Boveri AG Switzerland
Original Assignee
Bbc Brown Boveri & Cie
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Bbc Brown Boveri & Cie filed Critical Bbc Brown Boveri & Cie
Application granted granted Critical
Publication of US3915588A publication Critical patent/US3915588A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
    • F01D25/26—Double casings; Measures against temperature strain in casings

Definitions

  • a steam turbine casing for a high-capacity lowpressure section of two-shell construction divided along an axial plane comprises an inner casing in the [30] Foreign Apphc'atlon Pnonty Data form of a guide blade carrier to which the guide Oct. 16, 1973 SwItzerland 14646/73 blades are attached and an outer casing provided with a thermally-resilient lead-through for a steam inlet [52] 415M003 HS/103; 415/219 R pipe.
  • the inner casing is constructed from three frus- [51] Int. Cl.
  • This invention relates to an improvement in a steam turbine casing for high-capacity low-pressure sections of two-shell construction divided on an axial plane, comprising an inner casing in the form of a guide-blade carrier to which the guide blades are attached, and an outer casing provided with thermally resilient leadthroughs for the steam pipe.
  • the inner casing comprises essentially a number of annular discs arranged in radial planes and divided on an axial plane and which act as supporting elements.
  • the annular discs are supported with respect to each other, at the outer circumference, by means of cylindrical shell plates, and at the inner circumference by struts or bracing plates arranged parallel to the blade passage. Between the annular discs and the outer shell are chambers which are used for the extraction points for the various stages.
  • a further known technique in the case of steam turbine casings for low-pressure sections is to fit the inner casing with an internal casing structure for part of the guide blading, such that the inner casing can be considered as containing another inner casing.
  • the principal object of the invention is to provide a steam turbine casing which is simpler from the design standpoint and takes due account of hydrodynamic and thermodynamic considerations.
  • the inner casing essentially comprises frustum-shaped shells which are arranged approximately normal to each other and, in the region of the end of the steam inlet pipe, are joined to a cylindrical shell, the guide blading being carried by split rings fixed respectively to that circumference of the frustum-shaped shells which has the smaller diameter.
  • the steam inlet pipe or stub connection located on the inner casing can be of much larger diameter, the two inner frustom-shaped shells forming the steam inlet connection, for example, when the low-pressure section has a center-intake and steam flows in opposite directions to the discharge ends.
  • no actual stub connection needs to be provided in the inner casing.
  • the exhaust steam space between the outer casing and the outlet diffusor of the inner casing has a hydrodynamically more favorable shape, conforming better to the requirements of the condenser.
  • the smaller diameter ends of the frustum-shaped shells of the inner casing are provided with a ring flange to accommodate the guide blading.
  • the frustum-shaped shells of the inner casing for the internal rows of guide blades are connected by struts.
  • This version has the advantage that the struts are parallel to each other throughout, making them much easier to align during manufacture and erection.
  • the use in previous designs of struts and bracing plates in positions offset relative to each other has repeatedly necessitated extensive and difficult subsequent corrections during manufacture and erection of such casings.
  • the inner casing l is enclosed by an outer casing 2.
  • the inner casing 1 is formed by a frame comprising frustum-shaped shells 3, 4, 5, the shells 5 being enclosed at their larger circumference by a cylindrical shell '6.
  • the central steam inlet connection 7 terminates in this cylindrical shell 6, so that bounds of the inlet steam space 8 are determined by the frustum-shaped shells 5.
  • a number of steam inlet connections 7 can be located around the circumference of cylindrical shell 6.
  • the frustum-shaped shells 4 and 5 are preferably arranged approximately normal to frustum-shaped shell 3 and joined together by welding. This configuration results in small stresses at the joints or intersections while the inner casing is undergoing thermal expansion.
  • the broken line 23 indicates the outline of the frame established by shells 3, 4 and 5. From this it can be seen that linear expansion of frustum-shaped shells 3, 4 and 5 gives rise to virtually no change in the clearance between the fixed guide blades and moving blades on the rotor. Deformation arising from constraining or bending forces are also completely eliminated, thus providing a simple means of dealing more effectively with expansion due to thermal effects in such casings.
  • Support rings l3, l4 and 15 are rigidly fixed to the smaller diameters of frustum-shaped shells 3, 4 and 5, respectively. These rings are divided along an axial plane 24 corresponding to the basic construction of the casing.
  • the support rings 14 and 15 pertaining to frustumshaped shells 4 and 5 are braced relative to each other by means of struts 12.
  • the actual guide blade carrier 11, which forms the outer boundary of the flow passage 22, is fixed to the support rings 13, 14 and 15.
  • the guide blade carrier 11 consists of a number of segments 16, 17, 18, the innermost segment 18 forming the steam inlet stage.
  • the first row of guide blades 20 of this is arranged axially, for example, i.e., the steam is passed radially through one row of guide blades.
  • the carrier segments 18 are joined together by studs 21 and are adjustable.
  • Guide blades 19 are attached to segment 16 and also to the other segments 17 and 18. Segment 16 is at the same time contoured to form a diffusor at the steam outlet.
  • annular gaps 26 Between carrier segments 16 and 17 and between 17 and 18 are annular gaps 26 through which extraction steam is drawn off.
  • the extraction steam passes into spaces 9 and 10, where it can also be dewatered.
  • the spaces 9 and 10 are provided with manholes, not shown, thus allowing access.
  • the frustum-shapecl shells 4 and 5 and the segments 16, 17 and 18 of the guide blade carrier 11, which are divided along the axial plane of separation 25 of the casing, can be joined pennanently on the side of the inner casing 1 facing the flow passage 22.
  • connection flanges provided at the plane of separation 25 of the guide blade carrier segments 16, 17 and 18 do not have to project beyond the frame of the inner casing formed by frustum-shaped shells 3 to 6, but bring about a reduction in the cost of construction and the space required. Also, bringing the joint closure to the flow passage 22 has the effect of improving the tightness of the seal between the flanges, thus preventing the joints between the flanges from opening as a result of thermal expansion or other influences during operation.
  • the configuration of the inner casing 1 with the outer frustum-shaped shells 3 provides a hydrodynamically favourable shape for the exhaust steam spaces 24 at each end of the turbine, even though the construction results not only in a lighter casing, but also saves space for the same, or higher, unit capacity.
  • a steam turbine casing for a high-capacity lowpressure section of two-shell construction divided along an axial plane comprising an inner casing in the form of a guide blade carrier to which the guide blades are attached, and an outer casing provided with a thermally-resilient lead-through for a steam inlet pipe, said inner casing comprising three frustum-shaped shells two of which are arranged approximately normal to the other shell and in the region of said steam inlet pipe the other shell being joined to a cylindrical shell through which said steam inlet pipe passes, said guide blade carrier being supported by axially-divided rings fixed respectively to the circumference at the ends of the frustum-shaped shells which have the smaller diameter.
  • a dual-flow center-intake steam turbine casing for high-capacity low-pressure sections of two-shell construction divided along an axial plane comprising a dual-flow path inner casing in the form of a guide blade carrier to which the guide blades are attached, and an outer casing provided with at least one thermally resilient lead-through for the center-inlet steam pipe, wherein for each flow-path said inner casing essentially comprises three frustum-shaped shells two of which are arranged approximately normal to the other shell and said other shells in the region of the end of said centerinlet steam pipe are joined to the opposite ends of a cylindrical shell through which said center-inlet steam pipe passes, said guide blade carrier being supported by axially-divided rings fixed respectively to the circumference at the ends of the frustum-shaped shells which have the smaller diameter.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
US503386A 1973-10-16 1974-09-05 Two-shell axial-plane split casing structure for high-capacity low-pressure sections of a steam turbine Expired - Lifetime US3915588A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1464673A CH564680A5 (nl) 1973-10-16 1973-10-16

Publications (1)

Publication Number Publication Date
US3915588A true US3915588A (en) 1975-10-28

Family

ID=4402634

Family Applications (1)

Application Number Title Priority Date Filing Date
US503386A Expired - Lifetime US3915588A (en) 1973-10-16 1974-09-05 Two-shell axial-plane split casing structure for high-capacity low-pressure sections of a steam turbine

Country Status (11)

Country Link
US (1) US3915588A (nl)
BE (1) BE821026A (nl)
CA (1) CA1011125A (nl)
CH (1) CH564680A5 (nl)
DE (1) DE2358160A1 (nl)
ES (1) ES430998A1 (nl)
FR (1) FR2247612B1 (nl)
GB (1) GB1446267A (nl)
NL (1) NL7413452A (nl)
PL (1) PL94553B1 (nl)
SE (1) SE391374B (nl)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4277223A (en) * 1979-11-29 1981-07-07 Guy F. Atkinson Company Case construction for multi-stage pump
ES2052427A2 (es) * 1991-02-01 1994-07-01 Westinghouse Electric Corp Disposicion de soporte para optimizar las caracteristicas estructurales del cilindro interior de una turbina de vapor de baja presion.
US20070104572A1 (en) * 2005-11-07 2007-05-10 General Electric Company Methods and apparatus for channeling steam flow to turbines
US20080213091A1 (en) * 2007-03-02 2008-09-04 Heinrich Lageder Steam Turbine
US20090116957A1 (en) * 2004-08-23 2009-05-07 Max Wiesenberger Steam turbine with two steam chambers
EP2690253A1 (de) * 2012-07-27 2014-01-29 Siemens Aktiengesellschaft Niederdruck-Turbine
US9359913B2 (en) 2013-02-27 2016-06-07 General Electric Company Steam turbine inner shell assembly with common grooves
US10677092B2 (en) * 2018-10-26 2020-06-09 General Electric Company Inner casing cooling passage for double flow turbine

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH676735A5 (nl) * 1988-08-03 1991-02-28 Asea Brown Boveri
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

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2367134A (en) * 1943-05-29 1945-01-09 Westinghouse Electric & Mfg Co Steam chest construction
US3529901A (en) * 1968-11-18 1970-09-22 Westinghouse Electric Corp Turbine motive fluid inlet seal structure
US3594095A (en) * 1968-12-03 1971-07-20 Siemens Ag Casing for low-pressure stages of steam turbines of completely welded multishell construction
US3773431A (en) * 1970-12-08 1973-11-20 Bbc Brown Boveri & Cie Multiple shell turbine casing for high pressures and high temperatures

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2367134A (en) * 1943-05-29 1945-01-09 Westinghouse Electric & Mfg Co Steam chest construction
US3529901A (en) * 1968-11-18 1970-09-22 Westinghouse Electric Corp Turbine motive fluid inlet seal structure
US3594095A (en) * 1968-12-03 1971-07-20 Siemens Ag Casing for low-pressure stages of steam turbines of completely welded multishell construction
US3773431A (en) * 1970-12-08 1973-11-20 Bbc Brown Boveri & Cie Multiple shell turbine casing for high pressures and high temperatures

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4277223A (en) * 1979-11-29 1981-07-07 Guy F. Atkinson Company Case construction for multi-stage pump
ES2052427A2 (es) * 1991-02-01 1994-07-01 Westinghouse Electric Corp Disposicion de soporte para optimizar las caracteristicas estructurales del cilindro interior de una turbina de vapor de baja presion.
US20090116957A1 (en) * 2004-08-23 2009-05-07 Max Wiesenberger Steam turbine with two steam chambers
US8221063B2 (en) * 2004-08-23 2012-07-17 Siemens Aktiengesellschaft Steam turbine with two steam chambers
US7322789B2 (en) * 2005-11-07 2008-01-29 General Electric Company Methods and apparatus for channeling steam flow to turbines
CN1963158B (zh) * 2005-11-07 2011-05-25 通用电气公司 流动分离器和双流动蒸汽涡轮
US20070104572A1 (en) * 2005-11-07 2007-05-10 General Electric Company Methods and apparatus for channeling steam flow to turbines
JP2008240725A (ja) * 2007-03-02 2008-10-09 Alstom Technology Ltd 蒸気タービン
US20080213091A1 (en) * 2007-03-02 2008-09-04 Heinrich Lageder Steam Turbine
EP2690253A1 (de) * 2012-07-27 2014-01-29 Siemens Aktiengesellschaft Niederdruck-Turbine
WO2014016272A1 (de) * 2012-07-27 2014-01-30 Siemens Aktiengesellschaft Niederdruck-turbine
US9359913B2 (en) 2013-02-27 2016-06-07 General Electric Company Steam turbine inner shell assembly with common grooves
US10677092B2 (en) * 2018-10-26 2020-06-09 General Electric Company Inner casing cooling passage for double flow turbine

Also Published As

Publication number Publication date
BE821026A (fr) 1975-02-03
DE2358160A1 (de) 1975-04-17
PL94553B1 (pl) 1977-08-31
CA1011125A (en) 1977-05-31
FR2247612B1 (nl) 1978-07-07
NL7413452A (nl) 1975-04-18
GB1446267A (en) 1976-08-18
FR2247612A1 (nl) 1975-05-09
ES430998A1 (es) 1976-10-16
CH564680A5 (nl) 1975-07-31
SE391374B (sv) 1977-02-14
SE7412783L (nl) 1975-04-15

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