US3886906A - Steam generator - Google Patents

Steam generator Download PDF

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Publication number
US3886906A
US3886906A US422288A US42228873A US3886906A US 3886906 A US3886906 A US 3886906A US 422288 A US422288 A US 422288A US 42228873 A US42228873 A US 42228873A US 3886906 A US3886906 A US 3886906A
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US
United States
Prior art keywords
tubes
bundle
tube sheet
water
chamber
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
US422288A
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English (en)
Inventor
Hubert Wolfgarten
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.)
Gutehoffnungshutte Sterkrade AG
Original Assignee
Gutehoffnungshutte Sterkrade 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 DE19722259629 external-priority patent/DE2259629C3/de
Application filed by Gutehoffnungshutte Sterkrade AG filed Critical Gutehoffnungshutte Sterkrade AG
Application granted granted Critical
Publication of US3886906A publication Critical patent/US3886906A/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

  • the pipe has openings at its bottom end to [58] Field of Search 122/32, 33, 34 allow the water to enter the pre-heating chamber, and openings at the top end above the top cover plate of [56] References Cited the shell encasing the tube bundle for supplying feed- UNITED STATES PATENTS water to the steam separators on the cover-plate.
  • the present invention concerns a steam generator in the casing of which U-shaped tubes are installed through which a heating agent flows and which are fixed in a tube sheet.
  • One of the features of the previously known steam generators is a strong variation in the heat flow density or heating-area loading along the flow path in the tubes, as a function of the design of the tube bundle and the temperature characteristics.
  • the heating-area loading and as a consequence the steam generation rate per unit of area are proportional to the differential temperature between the tube-side and shell-side media. This leads to more steam being generated by the heating area located on the tube-inlet side than by the area on the tube-outlet side.
  • the one vertical heating-area half will generate about 65% and the other-only about of the total steam quantity produced. In operation, this results in inadequate water admission rate to the higher loaded heating-area half closely above the tube sheet in the outer space therefor, leading to deposition of material and tube damage by corrosion.
  • an unequal steam generation rate over the cross-section of the generator is accompanied by an unequal distribution of the specific density of the steam/- water mixture, causing unilateral mechanical stresses in the tube bundle on account of cross flow.
  • the temperature of the tube-side heating medium changes along the flow path as a function of the heat transfer rate, with saturation temperature of the mixture prevailing on the outer tube side.
  • the U-tube leg through which the medium flows first has a higher average temperature than a lower one. In operation, this difference in the average temperatures will lead to a different elongation of the tube legs, causing unilateral mechanical stresses in the tubes, particularly in the curved area.
  • the task of the present invention was to eliminate the above disadvantages inherent in steam generators previously known, by a different way of supplying and preheating the feed water.
  • this task is accomplished by an symmetrical arrangement of the U-tubes and by a pre-heating chamber encircling the outlet legs of the tubes along the longitudinal axis near the tube sheet and the side walls of which extend in axial direction, further by the provision of supply openings for the admission of feed water to the preheating chamber.
  • a particularly favourable effect can be achieved by designing the steam generator so that the outlet legs of the tubes are arranged around the central longitudinal axis of the generator, and by further installing along this axis an inner feed-water supply pipe extending close to the tube sheet.
  • a steam generator designed in accordance with the present invention offers the advantage of direct contact being established between the feed water and the heating areas, with the feed-water temperature not being increased through mixing with the return water.
  • Admission of an adequate quantity of water to the hot tube areas above the tube sheet is ensured by preheated feed water flowing in from the one side and return water from the other. Therefore, deposition of material on account of an inadequate water admission rate cannot occur.
  • a central collection chamber is arranged within the distribution chamber, with the outlet nozzle of the former running across the latter.
  • This nozzle can be designed to be supported by the outer shell, in this way carrying the tube sheet, the thickness of which can thus be reduced.
  • outlet openings incorporating a flow throttling device to permit the proportioned admission of a flow of feed water can be arranged in the inner pipe at the level of the top cover plate on which the steam separators are mounted.
  • the feed water admitted at this point at a rate of about 10% of the entire feed-water quantity is to ensure condensation of any steam possibly present in the return water.
  • the steam generator comprises a casing 1 into which U-tubes 2 are installed which are fixed in a tube sheet 3.
  • the heating agent is supplied through a distribution chamber 4 arranged below the tube sheet 3. After passing through the tubes 2, the heating agent enters a collection chamber 5 from which it is led off.
  • the tubes 2 are encased in a shell 6 extending down to near the tube sheet 3, with an annular clearance provided beween the shell 6 and the casing 1.
  • the shell 6 is sealed off by a cover plate 7 on which the steam separators 8 are mounted.
  • the U-tubes 2 are arranged symmetrically along the longitudinal axis leaving a free inner space in the longitudinal axis of the steam generator, through which an inner pipe 9 runs and which is sealed off from the shell 6.
  • the feed-water supply main 10 extends into this inner pipe 9, with a siphon-type steam trap 11 arranged at the inlet.
  • the inner pipe 9 extends down to near the tube sheet 3 and is closed at the bottom. Openings 12 provided in the inner pipe ensure the supply of feed water to a pre-heating chamber 13 described below.
  • the pipe 9 fills the entire free inner chamber of the steam generator where no tubes 2 are installed. Therefore, it can be dimensioned to serve as a water storage reservoir. In such a case, the annular clearance between casing 1 and shell 6 can be correspondingly smaller.
  • the inner pipe 9 is accessible and provided with lock-up inspection doors 14, permitting the inspection of at least part of the tubes 2 which was not possible at all with the steam generators previously known.
  • the inner pipe 9 has further outlets 15 the cross-section of which can be adjusted. These outlets 15 permit a part of the feed-water flow to pass through, with the main flow being admitted to the steam generator through the supply openings 12.
  • the feed water admitted through outlets 15 is mainly intended to condense any steam present in the return water from the steam separators.
  • the pre-heating chamber 13 encircling the outlet legs of tubes 2 has closed side walls 16 extending in axial direction along the central axis of the symmetrically arranged tube bundles.
  • the pre-heating chamber is divided by radial baffle plates 17.
  • Another flow of water consisting of return water and the smaller feed-water supply and coming from the annular clearance between the casing wall and the shell flows into the space between the tubes of the bundle. In this way, water will flow around the tubes from all sides thus avoiding the deposition of material in the lower tubebundle area.
  • the distribution chamber 4 has the form of a ring and incorporates an inlet nozzle 18 for the admission of the heating agent.
  • the chamber is accessible to permit the plugging of individual tubes 2 from the tube sheet should the need arise.
  • the distribution chamber includes a manway 19.
  • the collection chamber 5 is separated from the distribution chamber 4 by a cup-shaped plate 20.
  • the outlet nozzle 21 of the collection chamber 5 extends across the ring-shaped distribution chamber 4.
  • the outlet nozzle is arranged centrally and provided with slots 22 through which the heating agent flows from the collection chamber 5 into the outlet nozzle 21.
  • the nozzle 21 further has the function of an intermediate carrying element for support of the tube sheet 3 via a dished head of the casing 1. As a consequence, the thickness of the tube sheet can be reduced.
  • the collection chamber is likewise accessible.
  • the manway 23 of this chamber is arranged opposite the manway 19 of the distribution chamber 4. Due to this, the manway 23 can be opened from the outside. It would also be possible to enter the collection chamber through a nozzle extending across the distribution chamber 4 and closed at the outside.
  • a steam generator comprising a casing, a tube sheet, a bundle of U-shaped tubes having inlet and outlet legs mounted within said casing directing the flow of the heating agent, a shell encasing said bundle having a top cover plate, steam separators on said top plate, said bundle of tubes fixedly secured to said tube sheet and arranged symmetrically about the longitudinal axis of the steam generator, a pre-heating chamber encircling said outlet legs near said tube sheet for preheatingthe feed-water, the sides of said chamber extending axially, the supply means lying between the tubes of the tube bundle and extending into said chamber for admitting feed-water into said pre-heating chamber, said supply means comprises a pipe extending near said tube sheet, said pipe comprises outlet openings above said top cover plate, and said outlet openings having a flow throttling means for permitting a specified portion of the feedwater to flow around said steam separators.
  • a steam separator comprising a casing, a tube sheet, a bundle of U-shaped tubes having inlet and outlet legs mounted within said casing for directing the flow of a heating agent, a shall encasing said bundle having a top cover plate, steam separators on said plate, said bundle of tubes fixedly secured to said tube sheet and arranged symmetrically about the longitudinal axis of the steam generator, a pre-heating chamber encircling said outlet legs near said tube sheet for preheating the feed-water, the sides of said chamber extering said pipe.
US422288A 1972-12-06 1973-12-06 Steam generator Expired - Lifetime US3886906A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19722259629 DE2259629C3 (de) 1972-12-06 Dampferzeuger

Publications (1)

Publication Number Publication Date
US3886906A true US3886906A (en) 1975-06-03

Family

ID=5863641

Family Applications (1)

Application Number Title Priority Date Filing Date
US422288A Expired - Lifetime US3886906A (en) 1972-12-06 1973-12-06 Steam generator

Country Status (5)

Country Link
US (1) US3886906A (fr)
FR (1) FR2210273A5 (fr)
GB (1) GB1406560A (fr)
IT (1) IT1005516B (fr)
SE (1) SE388266B (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4593653A (en) * 1980-10-30 1986-06-10 Kraftwerk Union Aktiengesellschaft Distributor for two-phase mixtures, especially water-steam mixtures in forced-circulation boilers
US4697550A (en) * 1986-02-21 1987-10-06 Borsig Gmbh Device for cooling a reactor

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES8704251A1 (es) * 1980-07-21 1987-03-16 Kraftwerk Union Ag Perfeccionamientos en recipientes a presion, especialmente de reactores nucleares
FR2487951A1 (fr) * 1980-07-31 1982-02-05 Framatome Sa Distributeur pour l'admission d'un fluide a vaporiser dans un generateur de vapeur
FR2700383B1 (fr) * 1993-01-11 1995-02-10 Framatome Sa Echangeur de chaleur dans lequel l'alimentation en fluide secondaire s'effectue en partie haute par un boîtier d'alimentation ouvert vers le bas.

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147743A (en) * 1962-05-08 1964-09-08 Combustion Eng Vertical recirculating type vapor generator
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
US3360037A (en) * 1965-08-24 1967-12-26 Babcock & Wilcox Co Heat exchanger u-bend tube arrangement
US3437077A (en) * 1966-01-21 1969-04-08 Babcock & Wilcox Co Once-through vapor generator
US3467066A (en) * 1966-12-29 1969-09-16 Combustion Eng Stack drier for shell and tube vapor generator
US3483848A (en) * 1967-12-01 1969-12-16 Ramona Bernice Green Vapor generator with integral economizer

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147743A (en) * 1962-05-08 1964-09-08 Combustion Eng Vertical recirculating type vapor generator
US3298358A (en) * 1964-12-30 1967-01-17 Combustion Eng Vertical steam generator with a central downcomer
US3360037A (en) * 1965-08-24 1967-12-26 Babcock & Wilcox Co Heat exchanger u-bend tube arrangement
US3286696A (en) * 1965-10-29 1966-11-22 Combustion Eng Vertical steam generator with central downcomber
US3437077A (en) * 1966-01-21 1969-04-08 Babcock & Wilcox Co Once-through vapor generator
US3467066A (en) * 1966-12-29 1969-09-16 Combustion Eng Stack drier for shell and tube vapor generator
US3483848A (en) * 1967-12-01 1969-12-16 Ramona Bernice Green Vapor generator with integral economizer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4593653A (en) * 1980-10-30 1986-06-10 Kraftwerk Union Aktiengesellschaft Distributor for two-phase mixtures, especially water-steam mixtures in forced-circulation boilers
US4697550A (en) * 1986-02-21 1987-10-06 Borsig Gmbh Device for cooling a reactor

Also Published As

Publication number Publication date
SE388266B (sv) 1976-09-27
DE2259629A1 (de) 1974-06-20
DE2259629B2 (de) 1975-11-27
IT1005516B (it) 1976-09-30
FR2210273A5 (fr) 1974-07-05
GB1406560A (en) 1975-09-17

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