US3907029A - Steam generator - Google Patents

Steam generator Download PDF

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Publication number
US3907029A
US3907029A US392523A US39252373A US3907029A US 3907029 A US3907029 A US 3907029A US 392523 A US392523 A US 392523A US 39252373 A US39252373 A US 39252373A US 3907029 A US3907029 A US 3907029A
Authority
US
United States
Prior art keywords
tube sheet
tube
feed water
steam
nest
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
US392523A
Other languages
English (en)
Inventor
Heinrich Klein
Eduard Weber
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.)
Siemens AG
Siemens Corp
Original Assignee
Siemens Corp
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 Siemens Corp filed Critical Siemens Corp
Application granted granted Critical
Publication of US3907029A publication Critical patent/US3907029A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
    • 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 long 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 long 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/06—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall the conduits having a single U-bend
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/22—Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/02—Header boxes; End plates
    • F28F2009/0285—Other particular headers or end plates
    • F28F2009/029—Other particular headers or end plates with increasing or decreasing cross-section, e.g. having conical shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/22—Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates
    • F28F2009/222—Particular guide plates, baffles or deflectors, e.g. having particular orientation relative to an elongated casing or conduit
    • F28F2009/224—Longitudinal partitions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/22—Arrangements for directing heat-exchange media into successive compartments, e.g. arrangements of guide plates
    • F28F2009/222—Particular guide plates, baffles or deflectors, e.g. having particular orientation relative to an elongated casing or conduit
    • F28F2009/226—Transversal partitions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S165/00—Heat exchange
    • Y10S165/355—Heat exchange having separate flow passage for two distinct fluids
    • Y10S165/40—Shell enclosed conduit assembly
    • Y10S165/401—Shell enclosed conduit assembly including tube support or shell-side flow director
    • Y10S165/405—Extending in a longitudinal direction
    • Y10S165/407—Extending in a longitudinal direction internal casing or tube sleeve
    • Y10S165/409—Extending in a longitudinal direction internal casing or tube sleeve including transverse element, e.g. fin, baffle

Definitions

  • a steam generator includes a U-shaped nest of tubes PP N05 392,523 having vertical legs with their lower ends mounted in the holes of a circular tube sheet and centrally form- [30] Foreign Application Priority Data ing a vertical corridor or passage extending upwardly S t 4 1972 G 2243417 from the tube sheet, the nest and the upper surface of 6p ermany the tube sheet being enclosed for containment of water and generated steam. Feed water flows radially l65/l6ll,28lf2;g; inwardly from the periphery of the tube sheet towards Fie'ld 159 16]. its center, the heating fluid flowing through the tubes nest via the tube sheets lower surface. To prevent the feed water from prematurely converting to steam, or boiling, on the upper surface of the tube sheet and in the corridor or passage, means are provided for reinforcing the inward radial flow force of the feed water,
  • a nuclear reactor using pressurized-water coolant produces useful power via a steam generator characteristically comprising an upstanding, inverted, U-shaped nest of tubes through which the coolant is passed as a heating fluid, the tubes having vertical legs with lower ends mounted in the holes of a horizontal circular tube sheet and centrally forming a vertical corridor or passage.
  • An enclosure for the tube sheets upper surface and the tube nest contains water and generated steam.
  • the enclosure has a steam outlet in its top and means for flowing feed water into the enclosure radially inwardly from the periphery of the tube sheet and over the latters upper surface for conversion to steam by upward circulation through the tube nest.
  • One object of the invention is to prevent such premature conversion of the water to steam, or localized boiling, in a steam generator of the type described.
  • this object is attained by providing such a steam generator with means for reinforcing the inward radial flow force of the feed water over the upper surface of the tube sheet and within the lower portion of the passage or corridor formed by the tube nest, to an extent preventing the waters conversion to steam, or boiling, locally adjacent to the center portion of the flow over the tube sheet and upwardly through the passage or corridor.
  • the reinforcing means comprise making the tube pitch of the vertical legs of the tubes of the tube nest, smaller around the periphery of the tube sheet than at its central portion.
  • the tubes vertical legs are interspaced more closely together around the periphery of the tube sheet than at its central portion.
  • the feed water When introduced to the steam generator the feed water, of course, has a relatively low temperature, substantially below its boiling temperature at the pressures involved, and with the present invention, the feed water remains in its liquid phase throughout not only the peripheral portion of the tube sheet and tube nest, but centrally as well, as the feed water flows upwardly from the tube sheet through the tube nest, thus eliminating, or at least substantially reducing, the risk that the feed water will locally prematurely convert to steam so as to result in the buildup of undesirable deposits.
  • the feed water flow reinforcing means comprise a series of vertically interspaced annular plates having outer peripheral proportions of substantially the same diameter positioned to receive the initial feed water flow, and having inner diameters which progressively increase from the uppermost one of this series of plates downwardly to the lowermost one.
  • the flow reinforcing means comprise the upper surface of the tube sheet having substantially a convex surface. This may be done by making the entire tube sheet convex and with substantially the same thickness throughout, the bottom of the tube sheet then having a corresponding convexity, as by thickening the tube sheet appropriately, in which case the bottom of the tube sheet is a plane or flat surface.
  • FIG. 1 in vertical section shows the essential portions of a steam generator to the extent required to understand the invention
  • FIG. 2 is like FIG. 1 but shows a second example
  • FIG. 3 illustrates a third example.
  • FIG. 1 shows a steam generator 1 of the type used for generation of steam from the heat of a pressurized-water coolant in circuit with the pressure vessel of a nuclear reactor using such a coolant.
  • FIG. 1 shows the inverted U-shaped nest of tubes having the vertical inlet legs 3 and corresponding outlet legs 4, the innermost of the legs 3 and 4 necessarily forming a vertical passage or corridor 5.
  • the lower ends of the legs 3 and 4 are mounted in the holes of a circular, horizontal tube sheet 8 which divides the lower end of the cylindrical wall 9 of the generators casing.
  • this casing has its upper end formed as a steam dome having an outlet for the steam.
  • a cylindrical shell 10 Spaced inwardly from the wall 9, a cylindrical shell 10 separates the boiling space 11 in which the feed water rises in the direction shown by the arrow 11a.
  • the annular space 12 between the cylindrical walls of the two parts 9 and 10 form the descent space 12 down through which feed water descends for preheating and thermal circulation of the water; a feed water inlet (not shown) located in the upper part of the steam generator casing or housing maintains an input of water.
  • the lower end 13 of the shell 10 is spaced above an outer peripheral portion of the tube sheet 8, the feed water descending through the space 12 and, as indicated by the arrow 14, flowing radially over the upper surface of the tube sheet 15 for upward flow as indicated by the arrow 1 1a.
  • This radial flow of water should reach the center 15 of the tube sheet 8 and flow upwardly without initially boiling, until it reaches a higher portion of the boiling space 11, if the undesirable dcposits are to be avoided.
  • the steam generators casing or housing forms a hemispherical chamber 9a divided by a wall 9b into inlet and outlet coolant manifolds 9c and 9d respectively. Therefore, the coolant flow through the tubes of the tube nest is via the lower surface of the tube sheet 8, resulting in the upper surface of the tube sheet having relatively higher temperatures.
  • the innermost ones of the vertical tube legs 3 and 4 of the tube nest provide shorter coolant flow paths than do the outermost ones of these legs. If the radial inward feed water flow indicated by the arrow 14 is inadequate to provide a sufficient flow to the center 15 of the tube sheet 8 and upwardly through the tube sheet, the water will convert to steam or boil prematurely and form the undesirable deposits.
  • a reinforcement or increase in the radial inward flow 14 is provided by this invention. As previously indicated, the flow is upwardly from the tube sheet 8, the flow 14 therefore having both a radial force component and an upward axial force component.
  • such reinforcing means is provided, the tube pitch, or radial interspacing, of the tube legs 3 and 4 throughout the innermost portion' of the tube nest, this annular area being indicated at 16, being substantially twice as large as in the area outwardly and more adjacent to the periphery of the tube sheet 8 and the tube nest, indicated at 17.
  • the feed water entering over the upper surface of the tube sheet 8 and into the outer portion of the tube nest has its normal upward axial component reduced because of the increase density of the tube pitch, or in other words, the closer interspacing of the vertical tube legs adjacent to the peripheral portion of the tube nest.
  • the inward radial component is therefore increased or reinforced relative to the upward component, preventing the formation of stagnant or dead water zones adjacent to the tube sheet center l and upward therefrom, such as would result in pre mature conversion of water to steam, or boiling, in those areas.
  • annular flat plates or baffles are vertically interspaced, these baffle plates having outer peripheries of substantially the same diameter positioned to receive the initial feed water flow, again indicated by arrow 14.
  • This series of annular baffle plates may have outer peripheries which become larger, the outer peripheries of this series being located adjacent to the lower end 13 of the shell which, with the housing or casing 9 and the tube sheet 8, define an annular feed water inlet.
  • These baffles are marked through 23, their outer peripheries having diameters approximately the same as the diameter of the shell 10.
  • the inside diameters of the series of baffles 20 through 23 progressively decrease downwardly with respect to the series of baffle plates.
  • the lowermost baffle 20 closest to the tube sheet 8 has the smallest inside diameter, and the baffle 23, which is farthest away, has the largest inside diameter.
  • FIG. 3 shows a third example of a means for increasing the radial feed water flow component relative to its upward axial flow component. This is done in this instance by making the upper surface of the tube sheet 8 with a convex shape. As previously indicated, this may be done by appropriately thickening the tube sheet so that its lower surface remains a plane flat surface or, although not shown, by making the tube sheet with the same thickness throughout and with a corresponding concave lower surface.
  • the convex upper surface increases the upward axial component of the feed water flow, adjacent to the tube sheet center 15, to a greater extent than near the peripheral portion, this of necessity increasing the radial flow component towards the center portion 15.
  • the convex shape may be contoured to fit the naturally developing flow as indicated in FIG. 3. That is to say, the curvature may be such that the convexity gradually increases in degree towards the center 15 of the tube sheet 8. In any event, the convexity should be such as to adequately increase or reinforce the radial component of the feed water flow sufficiently to prevent localized boiling with the consequent formation of deposits which should be avoided.
  • a steam generator including an upstanding, inverted U-shaped nest of tubes through which heating fluid is passed, said tubes having vertical legs, a horizontal circular tube sheet having holes formed therethrough and in which the lower ends of said legs are mounted, an enclosure for the tube sheets upper surface and the tube nest for containing water and generated steam, means for flowing feed water into the enclosure radially inwardly from the periphery of the tube sheet and over the latters upper surface for conversion to steam by upward flow therefrom through the tube nest, and means for flowing the heating fluid through the tube nests tubes via the tube sheets lower surface;
  • the improvement comprises means for reinv forcing the inward radial flow force of the feed water to an extent preventing its conversion to steam locally adjacent to the central portion of the tube sheet and nest of tubes, said reinforcing means comprising a series of vertically interspaced annular plates having outer peripheral edges of substantially the same diameter all of which are positioned to receive the initial feed water flow via all of said edges, and having inner diameters which progressively increase from the uppermost one of said series downwardly to the lowermost one of the plates.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Commercial Cooking Devices (AREA)
US392523A 1972-09-04 1973-08-29 Steam generator Expired - Lifetime US3907029A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19722243417 DE2243417B2 (de) 1972-09-04 1972-09-04 Dampferzeuger, insbesondere fuer druckwasserreaktoren

Publications (1)

Publication Number Publication Date
US3907029A true US3907029A (en) 1975-09-23

Family

ID=5855459

Family Applications (1)

Application Number Title Priority Date Filing Date
US392523A Expired - Lifetime US3907029A (en) 1972-09-04 1973-08-29 Steam generator

Country Status (10)

Country Link
US (1) US3907029A (enrdf_load_stackoverflow)
JP (1) JPS4967003A (enrdf_load_stackoverflow)
BE (1) BE804274A (enrdf_load_stackoverflow)
CH (1) CH560867A5 (enrdf_load_stackoverflow)
DE (1) DE2243417B2 (enrdf_load_stackoverflow)
ES (1) ES418426A1 (enrdf_load_stackoverflow)
FR (1) FR2198088B1 (enrdf_load_stackoverflow)
GB (1) GB1439498A (enrdf_load_stackoverflow)
IT (1) IT995252B (enrdf_load_stackoverflow)
SE (1) SE389182B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4585053A (en) * 1982-09-02 1986-04-29 The United States Of America As Represented By The United States Department Of Energy Heat exchanger for reactor core and the like
US20040081609A1 (en) * 1996-04-03 2004-04-29 Green Martin C. Heat exchanger
US20070139888A1 (en) * 2005-12-19 2007-06-21 Qnx Cooling Systems, Inc. Heat transfer system
US20130125839A1 (en) * 2010-08-02 2013-05-23 L'air Liquide Societe Anonyme Pour L'etude Et L' Exploitation Des Procedes Georges Claude U-tube vaporizer

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5849482Y2 (ja) * 1977-06-20 1983-11-11 川崎重工業株式会社 煙管式給水ヒ−タ
US4704994A (en) * 1986-04-16 1987-11-10 Westinghouse Electric Corp. Flow boosting and sludge managing system for steam generator tube sheet

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3238729A (en) * 1962-07-23 1966-03-08 Ass Elect Ind Steam turbine power plants
US3387652A (en) * 1966-07-06 1968-06-11 Borsig Ag Heat exchanger reinforcing means
US3503373A (en) * 1966-09-01 1970-03-31 Westinghouse Electric Corp Vapor generating apparatus
US3566961A (en) * 1967-09-06 1971-03-02 Basf Ag Tubular reactor for carrying out endothermic and exothermic reactions with forced circulation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3238729A (en) * 1962-07-23 1966-03-08 Ass Elect Ind Steam turbine power plants
US3387652A (en) * 1966-07-06 1968-06-11 Borsig Ag Heat exchanger reinforcing means
US3503373A (en) * 1966-09-01 1970-03-31 Westinghouse Electric Corp Vapor generating apparatus
US3566961A (en) * 1967-09-06 1971-03-02 Basf Ag Tubular reactor for carrying out endothermic and exothermic reactions with forced circulation

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4585053A (en) * 1982-09-02 1986-04-29 The United States Of America As Represented By The United States Department Of Energy Heat exchanger for reactor core and the like
US20040081609A1 (en) * 1996-04-03 2004-04-29 Green Martin C. Heat exchanger
US7328738B2 (en) * 1996-04-03 2008-02-12 Cabot Corporation Heat exchanger
US20070139888A1 (en) * 2005-12-19 2007-06-21 Qnx Cooling Systems, Inc. Heat transfer system
US20130125839A1 (en) * 2010-08-02 2013-05-23 L'air Liquide Societe Anonyme Pour L'etude Et L' Exploitation Des Procedes Georges Claude U-tube vaporizer
US9109795B2 (en) * 2010-08-02 2015-08-18 L'Air Liquide Société Anonyme Pour L'Étude Et L'Exploitation Des Procedes Georges Claude U-tube vaporizer

Also Published As

Publication number Publication date
DE2243417A1 (de) 1974-03-28
JPS4967003A (enrdf_load_stackoverflow) 1974-06-28
FR2198088B1 (enrdf_load_stackoverflow) 1974-11-08
DE2243417B2 (de) 1976-07-29
SE389182B (sv) 1976-10-25
BE804274A (fr) 1973-12-17
ES418426A1 (es) 1976-03-16
IT995252B (it) 1975-11-10
GB1439498A (en) 1976-06-16
FR2198088A1 (enrdf_load_stackoverflow) 1974-03-29
CH560867A5 (enrdf_load_stackoverflow) 1975-04-15

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