US2834327A

US2834327A - Cantilever superheater tube support

Info

Publication number: US2834327A
Application number: US375237A
Authority: US
Inventors: John J Banker
Original assignee: Babcock and Wilcox Co
Current assignee: Babcock and Wilcox Co
Priority date: 1953-08-19
Filing date: 1953-08-19
Publication date: 1958-05-13
Anticipated expiration: 1975-05-13
Also published as: BE531111A

Description

May 13, 1958 J. J. BANKER I 2,834,327

CANTILEVER SUPERHETER TUBE SUPPORT Filed 19, 1953 3 Sheets-Sheet 1 INVENTOR ESI/01m J anker ATTORNEY May 13, 1958 .1. J. BANKER 2,834,327

CANTILEVER SUPERHEATER TUBE SUPPORT Filed Aug. 19, 1955 3 Sheets-Sheet 2 OOOOQOO o0000000o Si 1* E o o 0 @8i-.3 i?) INVENTOR #511 J Banker ATTORNEY May 13, 1958 J. J. BANKER 2,834,327

CANTILEVER SUPERHEATER TUBE SUPPORT Filed Aug. 19, 1953 5. Sheets-Sheet 3 ATTORNEY United States Patent O CANTILEVER SUPERHEATER TUBE `SUPPORT John J. Banker, Cranford, N. J., assignor to The Babcock & Wilcox Company, New York, N. Y., a corporation of New Jersey Application August 19, 1953, Serial No. 375,231

8 Claims. (Cl. 122-510) The present invention relates to the construction and Operation of vapor generating and superheating units, and, more particularly, to marine type water tube steam boilers of the two-drum type in which the steam superheating tube surface is located within or alongside an upright bank of steam generating tubes connecting the vertically spaced horizontally arranged drums.

In steam boilers of the character described the steam superheating tubes are usually horizontally arranged U- shaped tubes with the tube ends connected to vertical headers and the leg and loop portions of the tubes supported from one or more large diameter tubes arranged between the tube 'legs through special support castings carried by those tubes. Under the designed operating conditions for steam boilers of this type, the superheater tubes and supporting elements are contacted by the high temperature heating gases immediately on leaving the furnace; and, when those gases contain corrosive constituents, these parts will be `subjected to damage due to these severe operating conditions. Accessibility to these parts for inspection and repair is ordinarily diicult in view of the congested condition of the space occupied by the superheater, and it is usually necessary in replacing a defective part to remove adjoining nondefective parts which would otherwise not require replacement at that time. The prior superheater'tube arrangement and support, and location of the connected headers, usually requires that, in the replacement of a single tube, a number of tube ends be cut away from the headers to get at the affected tube in order to withdraw it through the end of the boiler in which the looped ends of the superheater tubes are located. This requires a considerable tube withdrawal space to be available at that end of the boiler. When the superheater headers are located at the end of the boiler opposite to the tube withdrawal space, additional space is usually required for an enclosure for 4the headers andassociated parts.

The main object of the invention is the provision of a vapor generating and superheatng unit of the character described, with an improved construction of the supporting provisions for vapor superheating tubes within a superheater cavity in a vapor generating tube bank whereby the superheating tubes and the supports therefor are accessible and readily replaceable.

A further and more specilic object is the provision of a two drum marine steam boiler of the character described with an improved construction of the supporting provisions for steam superheating tubes which extend horizontally in a superheater cavity of an upright steam generating tube bank, whereby allthe superheating tubes, and the supports therefor, are accessible for cleaning or replacement, and whereby individual tubes may be readily replaced without disturbance or damage to the remaining tubes or supports.

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 specification. For

ICE

descriptive matter in which I have illustrated and de-.

scribed a preferred embodiment of the invention.

Of the drawings:

Fig. l is a sectional elevation of a two drum water tube steam boiler constructed in accordance with my in- Vention;

Fig. 2 is a sectional plan View taken on line 2 2 of Fig. 1;

Fig. 3 is a detailed partial elevation View of a portion o-f a supporting water tube with the superheater tube supporting elements attached.

Fig. 4 is a horizontal sectional view taken on the line 4 4 of Fig. 3;

Fig. Sis a. isometric view of a superheater tube supporting finger; and

Fig. 6 is an isometric view of a superheater tube supporting bracket.

The marine steam generating unit illustrated comprises a casing 10 having a front wall 12, a rear wall 14,

side walls

16, 18, and roof 20. The

walls

12, 13, 16, and roof 2li, aid in dening a furnace chamber 22 at one side of the unit which is fired by a plurality of uid fuel burners 24 arranged to discharge through burner ports 26 in the front wall 12. A discharge chamber floor 28 is positioned below the lowermost burners.

The lluid heating section of the unit comprises an upper steam and water drum 30 and a lower water drum 32, both of which are horizontally arranged with their longitudinal axes in vertical alignment. The entire unit is bottom-supported as indicated in Fig. l, the upper drum being supported on the lower drum through a bank of vertically arranged steam generating or water tubes 34 having their opposite ends bent and radially connected to the corresponding drum. The innermost rows of water tubes 34a are o-f larger diameter and bent laterally to dene two staggered rows of water screen tubes separating the furnace chamber 22 from a space 36 extending the full length of the tube bank. The steam generating surface of the unit also includes oor tubes 38 extending from the drum 32 to a side Wall header 40, tubes 42, extending from the header 4G along wall 16 and roof 20 tothe drum 3l), and rear wall tubes 44 extending between upper and lower

rear wall headers

46 and 48, which in turn are lconnected to the drums 30 and 32 respectively.

At the outer side of the tube bank 34 is arranged an economizer formed by laterally spaced vertical platens A of multi-looped horizontal tubes 40 having their upper ends connected to an inlet header 52 and their lower ends to an outlet header 54. The loop portions of the economizer tubes extend through and are supported by vertical plates 56 adjacent the loop portions thereof. The upper end of the economizer is located in a breeching 58 leading to a stack connection.

In accordance with the invention, the steam superheating section of the unit is defined by rows of horizontally arranged nested U-shaped tubes 60a, 60h positioned in the space 36 between the main bank of steam generating tubes 34 and the screen tubes 34a. In the embodiment shown each superheater row consists of two nested U-shaped tubes with the legs of the inner tube 6ila spaced apart sufficiently, for example, 13%", to permit a man to walk therebetween for inspection or repairs.

In the embodiment shown, the looped ends of the outer tubes 60h are slightly spaced from the rear wall 14 and the adjacent Wall portions integrally formed and cooled by wall tubes 44a. The ends of the tubes 60a, 60h are bent laterally and then forwardly for connection to laterally spaced headers 62 and 64, which are vertically arranged at the outer side of the front wall 12. The wall portion between the diverging bent portions of the tubes 60 and the headers 62 and 64 is closed by one or more heat insulated hinged doors 66, which are used for access to the space 36. The headers 62 and 64, and fuel burners 24 are enclosed by an outer panelled. casing 68 which is arranged parallel with the furnace chamber front wall 12. The section enclosing the headers may be separated from the portion enclosing the burners by a partition 69. Combustion air ows downwardly through the casing burner section to the burner ports 26. As indicated in Fig. l, the headers 62 and 64 and associated tubes 60a, 60b are substantially co-extensive with the height of the space 36.

In accordance with the invention, the superheater tubes 60a, 601; are supported so as to remain in their designed.

spaced relation during operation and yet so they can readily be removed when replacement is necessary. For this purpose, pairs of large diameter supporting water tubes 70 with their ends connected to the drums 30 and 32 are arranged at opposite sides of the superheater tubes 60b adjacent the water tubes 34 on one side and 34a on the other. The superheater tubes 60a and 60b are supported from the water tubes 70 by individual cantilevertype support fingers 72, which interengage with socket recesses on tube support brackets 74. The support brackets 74 are attached at spaced vertical intervals to the water tubes 70 by means ofwelds as shown in Figs. 3 and 4.

Referring to Figs. 3, 4 and 6, each of the superheater tube supporting brackets 74 has a vertically extending concave back or web portion 74a shaped to fit the support tubes 70. The outer or web corners 74a on each bracket are bevelled, as at 74b, to permit easy weld applications to the spaces formed between the bevels and the support tube 70 when the bracket is in place against this tube. Projecting forwardly from web 74a are two parallel projecting portions or

fianges

74C and 74d which aid in defining two superjacent rectangular shaped sockets or recesses, an upper one 74f and a lower one 74g. These recesses are further defined by the inner surface 74h of web 74a, vertical front projections 74j on the inner faces of flanges 74e, 74d, and horizontal portions 74k. The flanges 74e and 74d have inner edge contours including quarter circular curved recesses 74l spaced vertically above semi-circular curved recesses 74m. Each of the recesses has the same radius of curvature as the associated superheaterv tube wall.

The superheater tube support fingers, which normally fit into the brackets 74 when the

superheater tubes

68a and 68b are supported from the support tubes in proper position, include a normally vertical rectangular finger 72a, having lugs, or trunnions, 72b projecting from each side of the top. These trunnions are shaped to fit into the bracket recesses 74f or 74g. The vertical back portion 72a is shaped to fit down into the brackets between the socket recesses and the fianges`74c, 74d flush against the web surface 74h. The support finger also comprises a normally horizontal portion 72g having semi-circular

curved recesses

72e, 72d, and 72e, 72f extending from side to side on both top and bottom.

To install the

superheater tubes

68a and 68b, brackets A are welded at spaced vertical intervals to corresponding support tubes 74). The brackets are arranged so that the parallel projecting portions of one set face those of another set on correspondingly opposite tubes 70. After the brackets are welded to the tubes in proper spaced alignment along the height of each support tube, the lowermost support fingers are inserted into the bracket recesses. In this position the vertical rectangular portions 72a ofI the fingers fit between the flanges 74e` and 74d, and the trunnions 72b t into either the socket recesses 74f or 74g, lesending on the desired position of the lowermost superheater tube nest. In the illustrated example the lowermost ngers are placed into the upper bracket recesses 741. The top curved recesses 72e of the fingers 72 continue the contour of the upper recesses 741 of the brackets 74, when a finger is in correct alignment in an upper bracket recess. Y

The ends of the

tubes

68a and 68b are fitted into position in the headers 62 and 64 before they are lowered all the way down onto the finger recesses, and welded in place in the headers once they are set in the recesses. As shown in Fig. 3, the superheater tubes 68b iit into the

recesses

72e and 741 formed between the brackets and connecting fingers and the tubes 68a fit into the finger recess 72e. Each complete length of superheater tube is supported from the tubes 70 at four positions, two on each side of the space 36. The brackets and associated fingers are aligned on all of the tubes 70 so as to support the superheater tubes in a slightly inclined position. After the first superheater tube nest row is in place, a second set of support fingers are placed into the lower recesses 74g of the next higher brackets. In these positions the finger recesses 72d and 72j fit closely over the

tubes

68a and 68b respectively. The second row of nested tubes isinstalled in a manner similar to the first, and so on along the full height of the tubes 70. The completed bank ofv superheater tubes extends substantially coextensive with the height of the space 36.

When the unit is shut down for inspection orrepairs, one or more panels in the wall 68 are removed, and the door 66.0pened to permit a workman to enter the space' 26 and move throughout the length thereof to inspect the superheater tubes and associated supporting elements.

The tube support brackets 74 are designed to be cooledv by the heat absorbing action of the associated supporting tubes 70. They are placed on only the inside faces of the tubes '70 out of the direct path of the oncoming heatingy moved through the opening closed by the door 66. New` finger castings can be fixed in place merely by inserting one in the bracket recesses. becomes damaged, it is merely necessary to burn away the connections of the remaining portion of the bracket and' weld a new one to the tube 70.

The superheater tubes can be individually removed by first removing each finger casting from the brackets starting from the top until the affected tube is reached. To do this it is necessary to spring each succeedingly lower tube nest up to a slight distance and remove each. nest support finger from its bracket until the damaged nest is reached. When only one tube of the nest is damaged, it.

alone may be cut away from its connections to the header and lifted upwards out of the nest. To do this, the tube is sprung together at the ends until the bent portions clear the space between the two headers, and then it is pulled out between these headers. New tubes may be similarly inserted and the rows and support fingers replaced in a.

manner similar to the way in which they were removed.

The described superheater construction and support permits easier and faster erection of the unit, reduces the floor space requirements for tube removal by permitting the tubes to be removed at the burner end of the unit. without requiring additional space for superheater header..

enclosure, insures a high degree of accessibility to the entire superheater and associated headers and their sup. portingy elements, and permits quicker and easier inspection and repair of all parts.

The superheater tube supporting provisions described' are also adapted for use where the wall tubes 44a are In the event the bracket also.

omitted and an opening or openings provided in the rear wall 14 for withdrawing the superheater tubes through the rear end of the boiler unit after their ends have been severed from the headers 62 and 64.

The superheater headers 62. and 64 may be partitioned to provide a steam flow through the tubes in one or more passes, or more than one in line headers may be used to accomplish the same result. w

While in accordance with the provisions of the statutes I have illustrated and described herein the best form of the invention now known to me, those skilled in the art will understand that changes vmay be made in the form of the apparatus disclosed without departing from the spirit of the invention covered by the claims, and that certain features of the invention may sometimes be used to advantage without a corresponding use of other features.

What is claimed is:

l. In a vapor generating and superheating unit having a uid circulation system and a heating gas pass, a Vertical bank of return bend horizontally arranged vapor superheating tubes disposed in said heating gas pass, a vertically extending support tube arranged alongside and laterally spaced from said tube bank and connected into said fluid circulation system, a plurality of superheater tube supports each comprising a bracket and a cantilever member, each [bracket being mounted on said support tube at vertically spaced positions along the length thereof and having at least one socket and one tube positioning recess, each cantilever member being releasably engaged at one end in said socket and arranged between vertically adjacent superheater tubes, each cantilever member being formed with a plurality of recesses arranged to receive said superheater tubes and cooperate with said bracket and vertically adjacent superheater tube supports to restrain lateral and vertical movements ofthe superheater tubes while permitting longitudinal movement thereof, said bracket tube positioning recess and one of said cantilever member recesses cooperating to form a seat to support one of said superheater tubes.

2. A superheater tube supporting apparatus comprising an upright fluid cooled supporting tube subject to high temperature heating gases, a bracket having a recessed socket portion and attached to said supporting tube, and a cantilever member having one end shaped to releasably interengage in said bracket socket and a projecting portion having at least one closely fitting tube positioning recess on the top and bottom thereof, said bracket also being formed with tube positioning recesses and cooperating with said cantilever to carry superheater tubes and maintain the spacing thereof, each bracket tube positioning recess cooperating with one of said cantilever member recesses to form a seat to support one of said superheater tubes.

3. In a vapor generating and superheating unit having a fluid circulation system and a heating gas pass; a vertical bank of return bend horizontally arranged vapor superheating tubes disposed in said heating gas pass, a pair of vertically extending support tubes at opposite sides of and laterally spaced from said tube bank and connected into said fluid `circulation system, a plurality of superheater tube supportsy each comprising a bracket and a pair of cantilever members, each bracket being mounted on said support tube at vertically spaced positions along the length thereof and having a pair of vertically spaced sockets and a plurality of tube positioning recesses, each cantilever member being releasablyengaged at one end in one of said sockets and arranged between vertically adjacent superheater tubes, said cantilever members being said superheater tubes and cooperate with said bracket and vertically adjacent superheater tube supports to restrain lateral and vertical movement of the superheater tubes While permitting longitudinal movement thereof,

each bracket tube positioning recess cooperating with one of said cantilever member recesses to form a seat to support one of said superheater tubes.

4. A tube supporting apparatus subject to high tem` perature heating gases comprising a fluid cooled tubular supporting member, a cantilever member formed with tube positioning recesses, a bracket of U-shaped crosssection arrangedto cooperate with said cantilever member to support tubes and including side and back portions delining a socket adapted to receive said cantilever member, said back portion being attached to said tubular supporting member, the outer edges of said side portions being formed with corresponding tube positioning recesses each pair of which cooperates with one of said cantilever member recesses to form a seat to support one of said tubes.

5. A superheater tube supporting apparatus subject to high temperature heating gases comprising a fluid cooled tubular supporting member, a cantilever member formed with tube positioning recesses, a bracket of U- shaped cross-section arranged to cooperate with said cantilever member to support superheater tubes and including side and back portions defining a socket adapted to receive said cantilever member, said back portion being concave on its outer side for attachment to said tubular supporting member, the outer edge of said side portions being formed with correspondingly located tube positioning recesses each pair of which cooperates with one of said cantilever mem ber recesses to form a seat to support one of said superheater tube.

6. A superheater tube supporting apparatus subject to high temperature heat-ing gases comprising a Huid cooled tubular supporting member, a pair of cantilever members each formed with tube positioning recesses, a bracket of U-shaped cross-section arranged to cooperate with said cantilever member to support superheater tubes and including side and back portions dening a pair of vertically spaced sockets each adapted to receive one of said cantilever members, said back portion being concave on its outer side for attachment to said tubular supporting member, the outer edges of said side portions being formed with vertically spaced correspondingly located tube positioning recesses each pair of which cooperates with one of said cantilever member recesses to form a seat to.support one of said tubes.

7. A tube supporting apparatus subject to high ternperature heating gases comprising a bracket having tube positioning recesses, and a cantilever member supported by and arranged to cooperate with said bracket to support and position tubes, said cantilever member comprising two leg portions arranged in L-like form, one leg being arranged to be received by and maintained in operative relationship with said bracket, the other leg being formed with a plurality of tube positioning recesses, each bracket tube positioning recess cooperating with one of said cantilever member recesses to form a seat to support one of said tubes.

' 8. A superheater tube supporting apparatus subject to high temperature heating gases comprising a bracket Lhaving tube positioning recesses, and a cantilever member supported by and arrangedto cooperate with said bracket to support and position superheater tubes, said cantilever member comprising two leg portions arranged in L- like form and having bosses projecting from opposite sides at the juncture thereof, one leg being arranged to be received by said bracket and maintained in operative relationship therewith by said bosses, the other leg being rformed with a plurality of superheater tube positioning formed with a plurality of recesses arranged to receive recesses, each bracket tubepositioning recess cooperating with one of said cantilever member recesses to support one of said superheater tubes.

(References on following page) References Cited in the le of this patent` UNITED STATES PATENTS Reed Nov. 26, 1918 Nelis Nov. 27, 1923 l 5 Luedinghaus Jan. 17, 1928 Boland May 20, 1947 y Jenne Dec. 28, 1954` Freeman Aug. 30, 1955` 8 FOREIGN PATENTS France July 16, 1934 France Mar. 6, 1944 Germany Oct. 4, 1939 Sweden 1942