CA2341279C - Feedwater header joint assembly - Google Patents

Feedwater header joint assembly Download PDF

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Publication number
CA2341279C
CA2341279C CA002341279A CA2341279A CA2341279C CA 2341279 C CA2341279 C CA 2341279C CA 002341279 A CA002341279 A CA 002341279A CA 2341279 A CA2341279 A CA 2341279A CA 2341279 C CA2341279 C CA 2341279C
Authority
CA
Canada
Prior art keywords
nozzle
flanged
foot
pipe
ring
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 - Fee Related
Application number
CA002341279A
Other languages
French (fr)
Other versions
CA2341279A1 (en
Inventor
James T. Boyd
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.)
BWXT Canada Ltd
Original Assignee
Babcock and Wilcox Canada Ltd
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 Babcock and Wilcox Canada Ltd filed Critical Babcock and Wilcox Canada Ltd
Publication of CA2341279A1 publication Critical patent/CA2341279A1/en
Application granted granted Critical
Publication of CA2341279C publication Critical patent/CA2341279C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22BMETHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00Component parts or details of steam boilers
    • F22B37/02Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10Water tubes; Accessories therefor
    • F22B37/104Connection of tubes one with the other or with collectors, drums or distributors
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22BMETHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00Component parts or details of steam boilers
    • F22B37/02Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10Water tubes; Accessories therefor
    • F22B37/14Supply mains, e.g. rising mains, down-comers, in connection with water tubes
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22BMETHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00Component parts or details of steam boilers
    • F22B37/02Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10Water tubes; Accessories therefor
    • F22B37/20Supporting arrangements, e.g. for securing water-tube sets

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Flanged Joints, Insulating Joints, And Other Joints (AREA)
  • Branch Pipes, Bends, And The Like (AREA)

Abstract

A joint assembly for sealedly connecting an end of a pipe or nozzle to an opening through a wall. The end of the pipe or nozzle has an annular, outwardly extending foot having a surface which rests against the wall. A bottom face of the foot has a groove which provides a lip that serves to center the pipe or nozzle in the opening. A seal weld extends around the annular foot and seals the pipe or nozzle to the wall. A flanged ring extends around the end of the pipe or nozzle for pressing the surface of the annular, outwardly extending foot against the wall and bolts or threaded studs secure the flanged ring to the wall. The joint assembly is particularly suited for use in a feedwater header joint assembly for a steam generator and, with minor modifications, can be used for sealedly connecting one or both ends of a riser pipe interconnecting a feedwater header ring to an inlet opening of a steam generator.

Description

casE 6090 FEEDWATER HEADER JOINT ASSEMBLY
FIELD AND BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates generally to the field of once through steam generators (OTSG's) used to produce steam for expansion through a steam turbine for the generation of electric power and, in particular, to a new and useful feedwater header joint assembly for providing leak-tight fits at flanged connections within a feedwater header/riser assembly and at the feedwater header and steam generator connection points.
DESCRIPTION OF THE RELATED ART
Known OTSG designs have been fabricated with an external feedwater header ring which was comprised of two (2) 180° arc segments. As illustrated in Fig. 1, each of the feedwater header ring segments 2 is provided with a plurality of vertical riser pipes 4 (typically 16 such riser pipes 4 on each feedwater header ring segment 2) exiting off of a top surface 6 of the feedwater header ring segments 2. Each riser pipe 4 was topped off with a 90° elbow 8 which was provided with a gasket bolting ring or flange 10. Each of these gasketed bolting flanges 10 attached to one of thirty-two (32) corresponding gasketed sealing faces 12 provided around the circumference of an outer shell 14 of the OTSG vessel (not shown). A similar gasketed bolting flange 10 and corresponding gasketed sealing face 12 with a bolt circle ring was also provided at each connection point of the vertical riser pipe 4 to the feedwater header ring 2.
There are several problems with this design. During the installation of the OTSG's at a power plant site, the.OTSG vessel itself was first installed into place and then the feedwater ring headers were fitted up to the OTSG vessel. Numerous alignment problems could occur due to the precise alignment required to produce a leak-tight joint in such gasketed and threaded joint assemblies, even with flange fittings at both ends of the riser pipes. Upon completion of the fit up of the components, the gaskets were observed to leak, even though the alignment and bolting had appeared to be successful, indicating that the gasket seating alignment had not been adequately attained. The use of a gasketed and threaded joint assembly does not guarantee a leak-tight fit. Further problems ensued upon the application of heat up and operational transient conditions to the assembled component.
As such, it would be desirable to provide an improved feedwater header joint assembly which overcomes the problems of the prior art designs.
SUMMARY OF THE INVENTION
The present invention provides a solution to the two main problems encountered with the prior art feedwater ring header assembly, namely: (1) the geometric fit up problems associated with the mufti-terminal point requirements of the existing feedwater distribution design; and (2) the problem of leakage. The present invention solves these problems by replacing the prior art flanged connection points with particularly designed welded closures, in combination with a bolted flange ring for structural stability.
Accordingly, one aspect of the present invention is drawn to a feedwater header joint assembly for sealedly connecting a feedwater header ring to an inlet opening of a steam generator. A riser pipe has a first end connected to the inlet opening of the steam generator and a second end connected to the feedwater header ring. A first joint assembly secures the first end of the riser pipe to the steam generator, the first joint assembly including a nozzle with an annular, outwardly extending foot resting on an outside shell of the steam generator. A seal weld seals the nozzle to the outside shell of the steam generator. A flanged ring extends around the nozzle for pressing the annular, outwardly extending foot of the nozzle against the outside shell of the steam generator. Finally, fastening means are provided for securing the flanged ring to the outside shell of the steam generator.
With minor modifications, the present invention can be used for sealedly connecting one or both ends of the riser pipe interconnecting the feedwater header ring to the inlet opening of a steam generator.
However, since the present invention has other applications besides that described immediately above, another aspect of the present invention is drawn to a joint assembly for sealedly connecting an end of a pipe to an opening through a wall having a bore. In this embodiment, an annular, outwardly extending foot is provided on the end of the pipe having a surface which serves to position the pipe against the wall and a lip which serves to center the pipe within the bore of the opening. The outwardly extending foot rests against the wall, and a seal weld seals the pipe to the wall. A flanged ring extends around the end of the pipe for pressing the annular, outwardly extending foot provided on the end of the pipe against the wall, and fastening means are provided for securing the flanged ring to the wall.
It will be appreciated that the present invention can be easily adapted to sealedly connect an end of a nozzle to an opening through a wall having a bore with minor modifications.
Yet still another aspect of the present invention is drawn to a joint assembly for sealedly connecting an end of a pipe having a surface and a lip to a flanged nozzle having a bore. This embodiment of the invention comprises: an annular, outwardly extending foot provided on the end of the pipe, and a flanged nozzle including a top portion having a counterbore is provided which accepts the lip of the pipe and a surface which sets against the surface provided on the end of the pipe so that the end of the pipe is centered within the bore and positioned against the flanged nozzle. A seal weld seals the lip of the pipe to the flanged nozzle, a flanged ring extending around an outside of the pipe is provided for pressing the annular, outwardly extending foot of the pipe against the flanged nozzle, and fastening means are provided for securing the flanged ring to the flanged nozzle.
According to the present invention, since the flange connection points no longer have gaskets and instead comprise a seal welded configuration, the leakages associated with a gasketed design are eliminated. The details of the assembly between the flange piece and the mating component are such that a positive interface is created to ensure hard metal-to-metal contact and minimization of relative motions between the two components. The seal weld provided for leakage elimination is positioned outboard of the positive fit and thus the seal welds only fimction to provide a leak tight joint. The flanged ring is assembled over the seal welded connection and is fastened down with studs to firmly seat the welded connection, while providing the major structural rigidity and strength of the joint. Flanges at both ends of the riser pipe assembly ensure that fixture inspection and possible replacement requirements for the internal feedwater distribution components is maintained, simply by removing the flanged bolt components and removal of the seal welds by grinding.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure.
For a better understanding of the invention, its operating advantages and specific benefits attained by its uses, reference. is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a sectional side view of a single feedwater riser pipe assembly interconnected between a feedwater header ring and a shell of an OTSG;
Fig. 2 is an enlarged, cross-sectional view of the upper portion of Fig. 1, illustrating a flanged and welded joint assembly according to the present invention as applied to a shell of the OTSG; and Fig. 3 is an enlarged, cross-sectional view of the lower portion of Fig. 1, illustrating a flanged and welded joint assembly according to the present invention as applied to a feedwater header ring.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, in which like reference numerals are used to refer to the same or fimctionally similar elements, Fig. 1 shows an improved feedwater header joint assembly generally designated 20 for providing feedwater from a feedwater header ring 2 via a vertical riser pipe 4 to an OTSG through an opening 16 in an outside shell 14 of the OTSG (the balance thereof not shown). For clarity purposes, only a single vertical riser pipe 4 is shown, but it is understood that in an actual installation, plural feedwater riser pipes 4 would be employed in between the feedwater header ring 2 and the shell 14 of the OTSG. The present invention provides easier installation fit-up and alignment of the vertical riser pipes 4 in between the feedwater header ring 2 and the shell 14, while still providing easy access for maintenance and removal of feedwater header components should the need arise, and a leak-tight fit at the connection points on both the feedwater header ring 2 and the shell 14.
Referring now to Fig. 2, the upper end of the improved feedwater header joint assembly 20 (which is connected to the shell 14 of the OTSG) comprises a nozzle 30 having an annular, outwardly extending foot 40 which rests on an outside surface 50 of the shell 14. Nozzle 30 is axially aligned and centered with the bore 60 of the inlet opening 16 through the shell 14 of the OTSG. The alignment and centering functions are provided by a bottom face of the annular, outwardly extending foot 40 of the nozzle 30 which is provided with a groove 70 and a lip 75.
The lip 75 serves to center the nozzle 30 within the bore 60 of the opening 16 while the groove 70 provides a surface which positions the nozzle 30 against the shell 14. A
circumferential seal weld 80 is deposited at a junction between an outer edge of the foot 40 and the outside surface 50 of the shell 14 of the OTSG. Extending around the outside of the nozzle 30 there is provided a flanged ring 90 having a lip 95 around the circumference thereof which is provided with a plurality of apertures 100. The flanged ring 90 is also axially aligned with the bore 60 of the opening 16. The apertures 100 in the flanged ring 90 correspond in number and arrangement to a plurality of apertures 110 provided in the shell 14 from the outside surface SO thereof.
Fastening means 120, advantageously in the form of threaded bolts or threaded studs and nuts, are provided to press the flanged ring 90 against the outwardly extending foot 40 of the nozzle 30, thereby securing the nozzle 30 against the shell 14 of the OTSG.
ZS As will be seen from Fig. 3, at the lower end of the improved feedwater header joint assembly 20 (which is connected to the feedwater header ring 2) there is provided a somewhat similar construction. The lower end of the vertical riser pipe 4 is also provided with an annular, outwardly extending foot 130. A bottom face of the annular, outwardly extending foot 130 is again provided with a surface 140 and a lip 150. The surface 140 serves to position the riser pipe 4 against a corresponding flanged nozzle 160 extending from the feedwater header ring 2, while the lip 150 serves to center the riser pipe 4 within a bore 155 of the flanged nozzle 160. The top portion of the flanged nozzle 160 is provided with a corresponding counterbore 170 which accepts therein the lip 150 of the riser pipe 4. The surface 140 of the riser pipe sets against a corresponding~surface 180 of the flanged nozzle 160. A circumferential seal weld 190 is deposited at the junction between the outer edge of the foot 130 and the surface 180 of the flanged nozzle 160. Extending around the outside of the lower end of the riser pipe 4 there is provided a flanged ring 200 having a lip 210 around the circumference thereof which is provided with a plurality of apertures 220. The apertures 220 in the flanged ring 200 correspond in number and arrangement with a plurality of apertures 230 provided in the flanged nozzle 160.
Fastening means, advantageously in the form of threaded bolts and nuts (not shown), are provided to press the flanged ring 200 against the outwardly extending foot 130 of the riser pipe 4 against the surface 180 of the flanged nozzle 160, thereby securing the riser pipe 4 against the flanged nozzle 160. Accordingly, for both Figs. 2 and 3, the fastening technique is the same.
While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
For example, while the present invention has particular application to the aforementioned feedwater header assemblies, it can be applied in other settings. The invention can be used wherever a leak-tight joint is needed, and/or where there is a need for a joint which can be quickly assembled, such as in the field, but which in all likelihood will never need to be disassembled.
Further, the present invention contemplates applications where only one flanged joint assembly will be required, as well as applications where two or more 'flanged joint assemblies will be required in a given piping installation.

Claims (3)

1. A joint assembly for sealedly and rigidly connecting an end of a metallic nozzle to an opening through a wall having a bore, the joint assembly comprising:
an annular outwardly extending foot provided on the end of the nozzle and having a surface for positioning the nozzle against the wall and a lip for centering the nozzle within the bore, the foot resting against the wall and having an outer edge;
a circumferential seal weld sealing the outer edge of the foot to the wall;
a flanged ring extending around the end of the nozzle for circumferentially pressing the foot against the wall; and detachable fastening means for rigidly securing the flanged ring to the wall.
2. A joint assembly for sealedly and rigidly connecting an end of a metallic pipe having a surface and a lip to a flanged metallic nozzle having a bore, the joint assembly comprising:
an annular outwardly extending foot provided on the end of the pipe and having an outer edge, a top portion of the flanged nozzle having a counterbore for receiving the lip of the pipe and a surface which sits against the surface provided on the end of the pipe so that the end of the pipe is centered within the bore and positioned against the flanged nozzle;
a circumferential seal weld sealing the outer edge of the foot to the surface of the top portion of the flanged nozzle;

a flanged ring extending around the end of the pipe for circumferentially pressing the foot against the flanged nozzles and detachable fastening means for rigidly securing the flanged ring to the flanged nozzle.
3. A feedwater header joint assembly for sealedly and rigidly connecting a feedwater header ring to an inlet opening of a once through steam generator, the feedwater header joint assembly comprising:
at least one riser pipe having a first end connected to the inlet opening of the steam generator and a second end connected to the feedwater header ring a first joint assembly securing the first end of the riser pipe to an outside shell of the steam generator including a nozzle with an annular outwardly extending foot having an outer edge, the foot having a bottom face with a groove for positioning the nozzle against the shell of the steam generator and a lip for centering the nozzle within a bore of the inlet opening;
a circumferential seal weld sealing the outer edge of the foot to the outside shell of the steam generator a flanged ring extending around the nozzle for pressing the foot of the nozzle against the outside shell of the steam generator, the flanged ring being provided with a plurality of apertures corresponding in number and arrangement to a plurality of apertures provided in the shell of the steam generator from the outside surface thereof;
detachable threaded fastening means for rigidly securing the flanged ring to the shell of the steam generator a second joint assembly for sealedly and rigidly connecting the second end of the riser pipe to a flanged nozzle having a bore, the flanged nozzle being connected to the feedwater header ring, the second end of the riser pipe having a surface and a lip and being provided with an annular outwardly extending foot having an outer edge, a top portion of the flanged nozzle having a counterbore for receiving the last named lip and a surface which sits against the surface provided on the end of the riser pipe so that the end of the riser pipe is centered within the bore and positioned against the flanged nozzle;
a circumferential seal weld sealing the outer edge of the last named foot against the flanged nozzle;
a flanged ring extending around the second end of the riser pipe for circumferentially pressing the last named foot against the flanged nozzles and detachable threaded fastening means for rigidly securing the last named flanged ring to the flanged nozzle.
CA002341279A 2000-03-21 2001-03-16 Feedwater header joint assembly Expired - Fee Related CA2341279C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US53171000A 2000-03-21 2000-03-21
US09/531,710 2000-03-21

Publications (2)

Publication Number Publication Date
CA2341279A1 CA2341279A1 (en) 2001-09-21
CA2341279C true CA2341279C (en) 2006-03-14

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
CA002341279A Expired - Fee Related CA2341279C (en) 2000-03-21 2001-03-16 Feedwater header joint assembly

Country Status (2)

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KR (1) KR100670419B1 (en)
CA (1) CA2341279C (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6708651B1 (en) 2003-05-05 2004-03-23 Babcock & Wilcox Canada Ltd. Feedwater apparatus

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Publication number Publication date
KR100670419B1 (en) 2007-01-17
KR20010089162A (en) 2001-09-29
CA2341279A1 (en) 2001-09-21

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Effective date: 20180316