US3915123A - Steam generator - Google Patents

Steam generator Download PDF

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Publication number
US3915123A
US3915123A US526944A US52694474A US3915123A US 3915123 A US3915123 A US 3915123A US 526944 A US526944 A US 526944A US 52694474 A US52694474 A US 52694474A US 3915123 A US3915123 A US 3915123A
Authority
US
United States
Prior art keywords
shroud
tube
plate
casing
bundle
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
US526944A
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English (en)
Inventor
Raimund Reisacher
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.)
Kraftwerk Union AG
Original Assignee
Kraftwerk Union AG
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
Priority claimed from DE19732358829 external-priority patent/DE2358829C3/de
Application filed by Kraftwerk Union AG filed Critical Kraftwerk Union AG
Application granted granted Critical
Publication of US3915123A publication Critical patent/US3915123A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B1/00—Methods of steam generation characterised by form of heating method
    • F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
    • F22B1/023—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers with heating tubes, for nuclear reactors as far as they are not classified, according to a specified heating fluid, in another group
    • F22B1/025—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers with heating tubes, for nuclear reactors as far as they are not classified, according to a specified heating fluid, in another group with vertical U shaped tubes carried on a horizontal tube sheet

Definitions

  • a steam generator of the type conventionally used as part of the coolant loop of a pressurized-water reactor comprises a vertical casing having its lower portion closed by a horizontal tube plate in which the bottoms of the tubes of the hot and cold legs of a U-tube bundle are mounted, the tube bundle extending upwardly within the casing and being encircled by a shroud having a bottom end spaced above the tube plate but adjacent to this plate, the shroud extending upwardly around the tube bundle to at least slightly above the top of the bundle.
  • This shroud forms an annular space between itself and the inside of the casing, the latter having a feed-water inlet and an enlarged upper portion having a top closed by a steam dome with a steam output nozzle, this enlarged portion normally containing an array of horizontally interspaced water separators mounted on top of the shroud.
  • a primary header below the tube plate sends the coolant from the reactor through the tube bundles hot leg and from the cold leg back to the reactor for cooling the reactors core.
  • Feed-water in the casing rises up through the shroud and the two tube bundle legs, while vaporizing, water separated from the steam by the separators, together with an input feed water feed through the feed-water inlet, descending in the annular descent space and flowing over the top of the tube plate to again rise within the shroud.
  • the feed water is maintained in circulation within the steam generator casing.
  • German Utility Model No. 7,226,418 suggests the possibility of positioning plates at the bottom of the shroud above the tube plate, the plates having holes formed in them and being inclined towards the tube plate to form with this plate a duct of wedgeshaped cross section.
  • the purpose is to equalize the flow over the tube plate but this arrangement substantially increases the flow resistance because the flow must not only be through the tubes of the tube bundle, but also is hampered by the flow equalizing plates.
  • the U-tube bundle has a generally cylindrical outside contour encircled by the shroud which is also generally cylindrical, the two legs being substantially semicylindrical in contour with flat interfacing sides formed by the innermost rows of the tubes. Because of the tube return bends at the top of the bundle, these flat sides are necessarily horizontally interspaced. The result is that the U-tube bundle contains a vertically extending corrodor free from tubes, extending vertically from the tube plate to the tube return bends of the innermost tubes and horizontally for the width of the tube bundle.
  • the feed water vaporizes to steam while rising through the shroud, through the tube bundle, and this space enclosed around the tube bundle: is normally called the boiling space. However, the feed water rising in the corridor is not in direct contact with the heat ex changer tubes and, therefore, receives no direct heat exchange from the reactor coolant.
  • interspaced, upstanding walls enclose the previously referred to corridor within and respect to the previously referred to flat sides of the tube bundle, but leaving this corridor open adjacently above the tube plate.
  • These walls extend transversely between and connect with the shroud and the shroud has openings above the tube plate and connecting with the corridor between the walls, and with the descent space formed between the shroud and the inside of the steam generators casing.
  • a duct is formed having narrow open sides, opening through the shroud, so that this duct forms a second descent space within the area formerly representing the corridor and up through which, with the prior art construction, the feed water ascended.
  • the feed water through the transverse openings through the shroud has access to the enclosed descent space between the two legs of the U-tube bundle, so that the down-flow, is through this second descent space, into the central portion of the tube plate.
  • downwardly converging baffle plates are positioned between the two walls forming the new descent space, and which define an opening substantially directly above or open to the central portion of the tube plate.
  • the two walls which define this new descent space between the two flat sides of the legs of the tube bundle may also be enclosed between their tops, and the funnel-like bottom of the new descent space may open at right angles with respect to the interspacing flat sides of the tube bundle, for flow over the tube plate, starting substantially at the center of the tube plate, and extending counterflow to the normal flow introduced peripherally towards the center of the: tube plate by the usual opening formed between the bottom of the shroud and the tube plate.
  • FIG. 1 is a vertical section through the described type of steam generator and oriented at right angles to the corridor formed between the two generally semicircular legs of the tube bundle;
  • FIG. 2 is the same as FIG. 1 but is taken on a plane rotated approximately with respect to the FIG. I view;
  • FIG. 3 is a cross section taken on the line IIIIII in FIG. 1.
  • FIG. 1 show a pressurized-water reactor steam generator comprising a mainly cylindrical vertical casing 1 having a lower end closed by a horizontal tube plate 2 below which is shown the usual semispherical header 3 forming an inlet or hot chamber 5 and an outlet or cold chamber 6, these chambers being separated by a partition 4.
  • the inlet chamber 5 has a nozzle 7 for connection into the coolant loop of a pressurized-water reactor (not shown), while the chamber 6 has a generally corresponding nozzle 8 for connection with the pipe of the loop that returns the coolant to the reactor, normally through the main coolant pump (not shown).
  • the bottom ends of the tubes of the hot leg 10 and cold leg 11 of the U-tube bundle 12, which may comprise around 1,000 tubes, are mounted in the tube plate -2 in the usual manner.
  • the two legs are, of course, interconnected by the top bend 13, the individual tubes all being U-shaped.
  • the casing 1 has above the tube bundle the usual enlarged portion which defines a space 14 into which the steam discharges and passes through the steam output in the steam dome (not illustrated).
  • this enlarged portion of the casing 1 there is a space 14 in which the water separators 16 are located by being mounted on top of the cylindrical shroud 15 which encircles the U-tube bundle of the heat exchanger.
  • Steam dryers are normally located above the separator 16 and within the steam dome which is not shown.
  • the steam represents the useful power output of the steam generator and, in turn, of the reactor (not shown).
  • the cylindrical shroud 15 has the bottom end spaced above the top of the tube plate 2, and a top end above the upper end of the U-tube bundle, as previously indicated.
  • the shroud forms an annular descent space 18 between itself and the inside of the casing l.
  • the casing 1 has a feed-water inlet 20 which through an annular distributing manifold 20a, feeds water uniformly above the annular descent space 18 formed between the cy lindrical shroud 15 and the cylindrical inside 1 of the casing.
  • the innermost tubes of the U-tube bundle heat exchanger shown at 21 and 22 where they extend through the tube plate 2, vertically define the corridor previously referred to and up through which the feed water normally ascends with the prior art constructions.
  • two downwardly converging baffle plates 40 are positioned between the two walls 25 and 26, the bottom ends of these walls opening above the tube plate 2 adjacent to its central portion, the previously referred to slots 15a extending downwardly only so far as is required to reach the tops of the converging baffle plates 40 which form a funnel of the lower portion of the new descent space.
  • the two walls 25 and 26 may have bottom ends substantially contacting the top of the tube plate 2, making allowance for thermal expansion clearance requirements, and both plates may have cutouts forming transverse outlets 34 and 35, and other cutouts 42 and 43 adjacent to the outer edges of the two plates.
  • the space between the two legs now forms a descent space.
  • the flow having access through the slots formed in the shroud, can be discharged inwardly and downwardly as shown by the arrows 40 in FIG. 2, with the flow discharging through the transverse openings 34 and 35, the downward descent flow thus being directed centrally to the generally centralized portion of the plate 2 and from there horizontally outwardly and into the two legs, now each substantially enclosed by the shroud l5 and one or another of the walls 25 and 26.
  • the openings 34 and 35 have differing cross-sectional areas.
  • the opening 34 leading over the plate beneath the hot leg 10 is from 50 to 500% larger than the opening 35 which feeds the Water from the new descent space, over the portion of the tube plate 2 below the cold leg.
  • the cross section ratio between the openings 34 and 35 is preferably about 4:1 so that the division of the flow rate between the two legs 10 and 11 in the ratio of 2:1 is provided.
  • the feed water descending normally in the descent space 15 can distribute over the top of the tube plate 2 by way of the cutouts 42 and 43.
  • the bottom edge of the shroud 15 is provided with inwardly extending flanges 45 which extend inwardly across at least several rows of the tubes of the two legs of the U-tube bundle, thus deflecting water from the descent space 15 inwardly, thus to some extent bypassing the descent water.
  • vertically disposed rods 61 can be positioned between the two walls 25 and 26 above the tube plate 2.
  • baffles may be arranged in the normal annular descent space outside of the shroud.
  • three rings 36, 37 and 38, provided with slots 39 may be positioned in the usual annular descent space 18.
  • One or another of these rings may be rotative relative to the. balance so that the slots 39 may be more or less mutually registered.
  • the feed-water supply indicated by the arrows 41 may have 40 to preferably 60%, of the total descent feed of water.
  • the passage openings 34, for the water descending through the new descent space 28 may be from 50 to 500% larger than the passage openings 35 which lead into the cold leg 1 l.
  • the cross sectional ratio between the openings 35 is preferably about 4:1 so that the division of the flow rate between the two legs 10 and 11 in the ratio of 2:1 is provided.
  • the two declining or converging plates or partitions 40 reduce the cross section of the new descent space 28 to less than one-third of the width of this space, thus providing a high velocity flow of the descending feed water directed against the generally central portion of the tube plate 2. It is this portion where with prior art constructions, water boiling is most apt to occur.
  • the inclined angles of the parts 40 is shown as being in the area of about 45%, but this angularity can be varied.
  • a steam generator comprising an upstanding casing having a lower portion, a tube plate closing said portion, a U-tube bundle heat exchanger inside of said casing and having upstanding legs with lower ends mounted in said plate, said bundle having a top formed by return tube bends joining said legs at said top and said legs forming flat'interfacing upstanding interspaced sides defining an upstandingcorridor between the legs below said top, a shroud having an open top and bottom encircling said bundle inside of said casing and forming an annular descent space between the shroud and the inside of said casing, the bottom of said shroud being spaced adjacently above said plate, means below said plate for passing a primary fluid through said bundle, means for introducing feed-water into said casing, a steam outlet for said casing, and interspaced, upstanding walls enclosing said corridor within and with respect to said flat sides of the tube bundle but leaving said corridor open adjacently above said tube plate, said walls extending transversely between and connecting with said shroud and the shroud having opening
  • the generator of claim 1 having means for forming a funnel for said corridor between said walls and above said plate and having an outlet mouth substantially over the center of the plate.
  • said funnelforming means comprise two downwardly converging baffle plates extending between said walls and with bottom ends adjacent to said plate, said openings in said shroud comprising slots formed longitudinally in the shroud from the upper ends of said walls down to the upper ends of said baffle plates.
  • one of said legs of said tube bundle is a hot leg and the other is a cold leg and the one of said openings facing said hot leg is larger than the one of the openings facing the cold leg.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Details Of Heat-Exchange And Heat-Transfer (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
  • Treatment Of Fiber Materials (AREA)
US526944A 1973-11-26 1974-11-25 Steam generator Expired - Lifetime US3915123A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19732358829 DE2358829C3 (de) 1973-11-26 Dampferzeuger

Publications (1)

Publication Number Publication Date
US3915123A true US3915123A (en) 1975-10-28

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US526944A Expired - Lifetime US3915123A (en) 1973-11-26 1974-11-25 Steam generator

Country Status (11)

Country Link
US (1) US3915123A (nl)
JP (1) JPS5828481B2 (nl)
AT (1) AT365761B (nl)
BE (1) BE822404A (nl)
CH (1) CH580252A5 (nl)
ES (1) ES432247A1 (nl)
FR (1) FR2252534B1 (nl)
GB (1) GB1485477A (nl)
IT (1) IT1025773B (nl)
SE (1) SE391019B (nl)
SU (1) SU745383A3 (nl)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4308914A (en) * 1979-03-19 1982-01-05 Anthony Ruhe Double plate flow distributor
US4736713A (en) * 1984-11-15 1988-04-12 Westinghouse Electric Corp. Foraminous or perforated flow distribution plate
US4967699A (en) * 1987-05-22 1990-11-06 Ab Asea-Atom Steam generator
EP2508799A1 (en) * 2011-04-04 2012-10-10 Mitsubishi Heavy Industries Steam generator
US20120294410A1 (en) * 2011-05-16 2012-11-22 Steinmoeller Franz E Pressurizer baffle plate and pressurized water reactor (pwr) employing same
US9558855B2 (en) 2011-11-10 2017-01-31 Bwxt Nuclear Energy, Inc. Pressurized water reactor with upper plenum including cross-flow blocking weir
US20170336147A1 (en) * 2016-05-19 2017-11-23 Borgwarner Emissions Systems Spain, S.L.U. Heat exchange device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103027098B (zh) * 2013-01-06 2014-12-10 河北诚业机械制造有限责任公司 一种真空制冷滚揉机

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3242909A (en) * 1964-12-04 1966-03-29 Foster Wheeler Corp Vapor generators
US3286696A (en) * 1965-10-29 1966-11-22 Combustion Eng Vertical steam generator with central downcomber
US3298358A (en) * 1964-12-30 1967-01-17 Combustion Eng Vertical steam generator with a central downcomer
US3329129A (en) * 1963-10-31 1967-07-04 Waagner Biro Ag Process and apparatus for generating steam

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3329129A (en) * 1963-10-31 1967-07-04 Waagner Biro Ag Process and apparatus for generating steam
US3242909A (en) * 1964-12-04 1966-03-29 Foster Wheeler Corp Vapor generators
US3298358A (en) * 1964-12-30 1967-01-17 Combustion Eng Vertical steam generator with a central downcomer
US3286696A (en) * 1965-10-29 1966-11-22 Combustion Eng Vertical steam generator with central downcomber

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4308914A (en) * 1979-03-19 1982-01-05 Anthony Ruhe Double plate flow distributor
US4736713A (en) * 1984-11-15 1988-04-12 Westinghouse Electric Corp. Foraminous or perforated flow distribution plate
US4967699A (en) * 1987-05-22 1990-11-06 Ab Asea-Atom Steam generator
EP2508799A1 (en) * 2011-04-04 2012-10-10 Mitsubishi Heavy Industries Steam generator
US9182113B2 (en) 2011-04-04 2015-11-10 Mitsubishi Heavy Industries, Ltd. Steam generator
US20120294410A1 (en) * 2011-05-16 2012-11-22 Steinmoeller Franz E Pressurizer baffle plate and pressurized water reactor (pwr) employing same
US8681928B2 (en) * 2011-05-16 2014-03-25 Babcock & Wilcox Canada Ltd. Pressurizer baffle plate and pressurized water reactor (PWR) employing same
US9558855B2 (en) 2011-11-10 2017-01-31 Bwxt Nuclear Energy, Inc. Pressurized water reactor with upper plenum including cross-flow blocking weir
US20170336147A1 (en) * 2016-05-19 2017-11-23 Borgwarner Emissions Systems Spain, S.L.U. Heat exchange device

Also Published As

Publication number Publication date
IT1025773B (it) 1978-08-30
ES432247A1 (es) 1977-02-01
JPS50112601A (nl) 1975-09-04
BE822404A (fr) 1975-03-14
FR2252534B1 (nl) 1979-08-24
DE2358829B2 (de) 1976-05-13
AT365761B (de) 1982-02-10
CH580252A5 (nl) 1976-09-30
SE7414308L (nl) 1975-05-27
ATA893774A (de) 1981-06-15
FR2252534A1 (nl) 1975-06-20
JPS5828481B2 (ja) 1983-06-16
DE2358829A1 (de) 1975-05-28
GB1485477A (en) 1977-09-14
SU745383A3 (ru) 1980-06-30
SE391019B (sv) 1977-01-31

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