US3034485A - Tubular wall construction - Google Patents

Description

May 15, 1962 R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 1 Filed June 24, 1959 INVENTORS Rlchard H. Evans BY Leslie R Purple ATTORNEY May 15, 1962 R. H. EVANS ETAL 3,034,435.

TUBULAR WALL CONSTRUCTION Filed June 24, 1959 6 Sheets-Sheet 2 g io/c INVENTORS Richard H. Evans y Leslie P. Purple ATTORNEY May 15, 1962 R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 3 Filed June 24, 1959 IINVENTORS v Rlchard H.Evans Leslle P. Purple ATTORNEY May 15, 1962 R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 4 Filed June 24, 1959 INVENTORS Rlchard H. Evans BY Leslie P. Purple ATTORNEY May 15, 1962 R. H. EVANS ETAL TUBULAR WALL CONSTRUCTION 6 Sheets-Sheet 5 Filed June 24, 1959 May 15, 1962 R. H. EVANS ETAL 3,034,485

TUBULAR WALL CQNSTRUCTION Filed June 24, 1959 6 Sheets-Sheet 6 INVENTORS Richard H. Evans BY Lesl'geP. Purple ATTORNEY I United States Patent 3,034,485 TUBULAR WALL CONSTRUCTION Richard H. Evans, Leatherhead, and Leslie P. Purple,

London, England, assignors to Bahcock & Wilcox, Limited, London, England, a company of Great Britain Filed June 24, 1959, Ser, No. 822,481 Claims priority, application Great Britain Get. 17, 1953 7 Claims. (Cl. 122-510) This invention relates to tubular vapor generating and vapor heating units and ,more particularly to units adapted to generate steam at high pressures and to superheat the steam to high temperatures. In order to attain a required high temperature of superheat, the use of a section of radiant superheater may prove desirable or necessary. The section of radiant superheater may conveniently be suspended from above but the temperatures and pressures to which the tubes of the superheater are raised render them liable to become distorted unless guide or positioning means are provided.

An object of the invention is the provision of a furna ce Wall including both vapor generating and vapor superheating tube lengths, in which the superheating tube lengths are maintained in position, but from which the superheating tube lengths may readily be removed.

The above object and other features and advantages are attained in a vapor generating and vapor heating unit having a furnace chamber with a wall including a row of upright vapor generating tube lengths with suitable positioning means adapted to maintain the tube lengths in alignment with one another. Vapor superheating tube lengthsare disposed adjacent the vapor generating tube lengths and arranged to be exposed to radiant heat from the furnace chamber, the superheating tube lengths being maintained in position adjacent vapor generating tube lengths by coupling means which accommodate axial movements of the superheating tube lengths relative to the vapor generating tube lengths due to difierential thermal expansion. The coupling means are such that a superheating tube length may be uncoupled from the vapor generating tube lengths by an axial movement followed by a movement inwards of the furnace chamber.

According to the present invention, a group of at least two of the superheating tube lengths extends between two spaced vapor generating tube lengths and the coupling means, including a runner member, connects to all the superheating tube lengths of the group.

The invention will now be described, by way of example, with reference to the accompanying partly diagrammatic drawings in which:

FIG. 1 isa view of a fragmentary part of the furnace face of a furnace wall incorporating both vapor generating and vapor superheating tube lengths.

FIGS. 2A and 2B are sectional side elevations of a fragmentary portion of the vertical lower and'upper parts respectively of the wall taken on the line II-II of FIG. 1, FIG. 2B being drawn to a larger scale than FIG. 2A.

FIG. 3 is a sectional plan view of a fractional part of the wall taken on the line III-J11 of FIGS. 1 and 213.

FIG. 4 is a sectional plan view taken on the line 1VIV of FIG. 1.

FIGS. 5 and 6 are sectional plan views similar to the plan view of FIG. 3, but respectively showing two modified arrangements of positioning means coupling the which over a lower part of the wall are tangentially arranged and which are provided on their outer sides in usual manner with buckstays (not show) by which the tubes are maintained in alignment with one another and, Where-bent from the plane of the wall, at their desired spacing. A nun sheet metal casing 1:12, FIG. 2A, is disfrom the furnace chamber and is welded to channels 119 provided on certain of the tube lengths 101 at spaced intervals. The tube lengths 101 are connected at their lower and upper ends to suitable inlet and outlet headers (not shown) respectively.

Superheating tube lengths 105, suspended from above in convent onal manner and extending down the upper part of the furnace wall, are disposed in groups of six at regular intervals across the furnace wall face. Thus every fourth vapor generating tube length 101 (designated 101D) remains in the general plane of the furnace wall. Of the three remaining tube lengths 101A, 101B, and 1tl1C in each set of four, the center tube length 101B is bent outwardly from the plane of the wall at one level and its two flanking tube lengths 101A, 101C are bent outwardly in a similar manner at a somewhat lower level. The three tube lengths 101A, 101B, 101C above the higher of these two levels extend tangentially side by side to the top of the furnace wall. 7

Each group of six superheating tube lengths lies in one of the spaces so formed in the furnace wall face as a straight row of tangentially arranged tube lengths having their sides towards the furnace chamber arranged coplanar with the furnace chamber sides of the adjacent vapor generating tube lengths 101D. Thelower. ends of the superheater tube lengths 105 are welded to hollow stubs provided on a distributor 1&6 and, with the tube lengths 191A, 101B and 101C bent in this manner, apertures 107, 108 and 109 (see FIG. 4) are left'respectively between tube lengths 101D and 101A, tube lengths 101A and 101C, tube lengths 101C and ltllD and these facilirate the passage of the tube lengths 105 through the furnace wall.

Thus, identifying the superheater tube lengths 105 of a group from left to right of FIG. 4 by the reference numerals 105A to 1055, tube lengths 105A, 105C extend sidewardly through the aperture 107, tube lengths 1053 and 105E extend first under the center vapor generating tube 13113 and then through the aperture 108, while the tube lengths 105D, 105E extend sidewardly through the aperture 1S9. It will be noted that none of these tubes rise towards the distributor 106, and therefore they can be fully drained.

The sheet metal casing 102 extending over the part of the furnace Wall provided with the superheating tube lengths terminates above the distributor 106. To seal the Wall in the region of the distributor 106 against the escape of hot furnace gases a two part cowl 117, 118 is provided. Each part of the cowl is L-shaped in transverse cross-section. The upper part 117 is secured in gas-tight manner to a channel 119 to which is welded the lower end of the adjacent part of the casing 102 and part 117 is also Welded to a fin 120:extending from the distributor 106. The lower cowl is similarly secured in gastight manner to a Cl12111116l '121 welded to the upper end of a part of the casing 102 which extends below the distributor 106 and'to a fin 122 extending from the distributor. Below the distributor 106 the casing is welded to channels 121 welded to the'tubes 101. The ends of the space between the cowls and the furnace wall are closed in any suitable manner.

In theiembodiment of the invention illustrated, the vapor generating tube lengths 101,11ave an outside diameter of 3 inches, the superheating tube lengths 105 are of 1 /2 inches outside diameter.

Coupling means for maintaining the superheating tube lengths in position adjacent the vapor generating, tube lengths while accommodating axial movements of the superheating tube lengths relative to the vapor generating tube lengths due to differential thermal expansion are indicated generally at 130 in FIGS. 23 and 3. Such coupling means are provided at vertically spaced intervals along the superheating tube lengths, and in the embodiment illustrated occur at intervals of 8 feet.-

Referring to the embodiment of FIG. 3, each coupling be swung forwardly into the furnace chamber 103., By moving the superheating tube lengths upwardly, the bar means 133 passes over the tops of theguide'members 139 at each of the vertically spaced coupling means. The bar 133A is then removed laterally enabling the second bar 13313 to be moved in the direction of the furnace chamber to disengage the stirrups 131 from the vertical slots 144 and then withdrawn laterally from the stirrups. The six superheating tube lengths are then unconnected with one ranotherand can be replaced with new tube lengths, by a reversal of the above process, these new tube lengths then being welded at their ends to the stubs provided on the headers. i

The arrangement shownin FIG. 5 is'applicable to a furnace wall in which the superheating tube lengths extendnot only down an upper part of the furnace wall but also down to the foot of that wall. In such a case there is no need to bring the superheating tube lengths 105A to main quite close to the remaining vapor generatingtube lengths 101D, giving a relatively thin wall. The vapor me'ans'comprisessix G-shaped stirrups or brackets 131: 1

welded severally to the six superheating tube lengths 105, the stirrups extending away from the furnace chamber 103 and tie bar or runner means 133 extending through the stirrups 131, the runner means 133 being formed with a head portion 135 having near its opposite ends shoulders 137 facing the furnace chamber for engaging two guide members 139 welded respectively to two of the vapor generating tube lengths 101D. The guide members 139 connected to tubes 101D extend toward one another to reduce the free space between these tube lengths.

7 Thus each guide member 139 is in the form of a rectangular strip having a thickness of /2 inch and 7 inches long, the presence of these guide members thus reducing the free space between the two tube lengths 101]) in the region of the coupling means from 9 inches to 8 inches. The head portion 135 has an overall length of 8% inches. The space 143, FIG. 2B, inside each bracket or C-shaped stirrup 131 has a height of 3 /2 inches and a depth of 2% inches, and the bar means 133 have a height of 2 /2 inches. The bar means is in the form of two bars 133A and 133-B, the former being disposed closer to the furnace chamber 103. The bar 13313 which is 1% inches thick, forms the head portion 135 and is provided on its outer side with three vertical slots 144 for accommodating two of the stirrups 131. The bar 133A, that nearer the furnace chamber, is inch thick.

With the arrangement of vapor generating tube lengths 101 and superheating tube lengths 105 and coupling means 130 described above, the occurrence of differential thermal expansion between two superheating tube lengths 105 of the same group is accommodated by the arrangement of C-stirrups 131 and the bar means 133; Diiferential thermal expansion between the superheating tube lengths 105 and the vapor generating tube lengths 101 is accommodated by sliding movement of the bar means 133 relative to the guide members 139. Such movement will not be sufficient for the bar means to pass beyond the guide members 139, so that at all times the superheating tube lengths 105 are held in alignment with one another by the bar means 133 and held in place relative to the vapor generating tube lengths 101 by the coupling means.

When it is desired to replace one of the superheating tube lengths which has deteriorated in service, all six tubes of that group are disconnected at their ends from the associated headers or distributors, this involving cutting each tube length at each end adjacent the stub provided on the header. The superheating tube lengths 105 are then moved vertically upwards about three inches, so that the lower ends of the superheater tube lengths can generating tube lengths 101A, 10113 and 101C are spaced apart and diametrically opposite fins 301 provided on the tube length 101B and rearwardly directed fins 303 provided on the tubelengths 101D substantially close the inter-tube-length spaces between the tubes 101 and thus screen the thin metal casing 102 from heat radiated by the superheating tube lengths.

Of the six superheating tube lengths 105A to 105F', tube lengths 105B and 105E are providedwith C-shaped stirrups 131 through whichris threaded a bar or runner 133' having shoulders 137' arranged to contact guide members 139' Welded to the vapor generating tube lengths 101D. superheating tube lengths 105A, 1050* are secured to superheating tube lengths 1105B by short lengths of rod 305 which extend in the same direction as the tube lengths and are welded to' the tube length 105B and either tube length 105A or 105C on the side of those tube lengths remote from the furnace chamber 103.

' The guide member 139' is eight inches long and the coustirrups 131 do not fit within grooves in bar 133, this bar may be slid freeof the stirrups once the superheating tube lengths have been moved upwardly and forwardly into the furnace chamber, so releasing the tube lengths A to 1051 a FIGS. 6 and 7 show an arrangement in which, of the six superheating tube lengths 105A to 105F", the center four tube lengths 1053" to 105E are provided with brackets or G-shaped stirrups 131 fitted severally into slots 144" in bar 133B", and each of the end tube lengths 105A", 105F" is connected to the adjacent tube length 10513" or 105E" by hinges 461 arranged'with their axes parallel to those of the tube lengths. Thus the hinge 461 joining lengths 105E, 105F" comprises three tubular members 461A, 461B, 461C threaded on a hinge pin 461D secured by a weld 463' to the upper member 461A. The hinge 461 is disposed on the side of the superheating tube lengths remote from the furnace chamber, the members 461A, 461C being welded to the tube length 105E" and the member 461A being welded to the tube length 105E". Apart from these features, the construction of FIG. 5 is similar to that of FIG. 3 and the same numerals are used to denote similar parts.

In the various embodiments of the invention described above the coupling means between the superheating tube lengths and the vapor generating tube lengths permit differential thermal expansion of those tube lengths and'permit the removal of superheating tube lengths from the wall, after cutting of their ends, by a vertical movement followed by an outward movement into the furnace chamber.

While the instant invention has been disclosed with reference to a particular embodiment'thereof, his to be appreciated that the invention is not to be taken as limited to all of the details thereof as modification and variations thereof may be made without departing from the tube having an outer side, a readily detachable coupling.

means for maintaining said vapor heating tubes in relative alignment to each other and to said vapor generating tubes, said coupling means including aligned brackets mounted on the outer side of said vapor heating tubes, and a tie bar slidably received in said brackets and having end shoulder portions arranged to abuttingly engage said spaced vapor generating tubes for guiding the movement of said vapor heating tubes relative said generating tubes during thermal expansion and contraction thereof.

2. The invention as defined in claim 1 wherein said tie bar brackets have a C-shaped formation with opposed leg portions connected to said vapor heating tubes.

3. In a vapor generating and heating unit, a tubular wall arrangement defining a boundary wall portion of a chamber, said tubular wall including a pair of spaced, longitudinally extending, vapor generating wall tubes arranged tangent to the plane of said wall, a plurality of longitudinally extending vapor heating tubes occupying the space formed between said vapor generating tubes, said vapor heating tubes being disposed substantially tangent to said plane of said wall, and coupling means to maintain said vapor heating tubes in relative alignment to each other and to said vapor generating tubes, said coupling means accommodating longitudinal movement of said vapor heating tubes relative to said vapor generating tubes and to each other as occasioned by the differential thermal expansion therebetween, said coupling means including a guide member attached to each of said generating tubes so as to extend inwardly into the space formed between said generating tubes to reduce the distance therebetween, a plurality of brackets, each of said backets'being connected to one of said vapor heating tubes on a portion thereof opposite that portion of the tubes tangent to the plane of said wall, and a tie means adapted to be received in said brackets for maintaining said vapor heating tubes in coplanar alignment, said tie means including a bar means having shoulder portions to accommodate said guide members for maintaining said aligned vapor heater tubes in position relative to said generating tubes.

4. The invention as defined in claim 3 wherein said bar means is provided with a plurality of notches longitudinally spaced along the outer edge portion thereof and adapted to embrace said brackets, and a second bar extending transversely within said brackets and disposed between the vapor heating tubes and said bar means to hold said bar means-in position.

5. In a vapor generating and heating unit, a tubular wall arrangement defining a boundary wall portion of a chamber, said tubular wall including a pair of spaced, longitudinally extending, vapor generating wall tubes arranged tangent to the plane of said wall, a plurality of longitudinally extending vapor heating tubes occupying the space formed between said vapor generating tubes, said vapor heating tubes being disposed substantially tangent to sm'd plane of said wall and coupling means to maintain said vapor heating tubes in relative alignment to each other and to said vapor generating tubes, said coupling means accommodating longitudinal movement of said vapor heating tubes relative to said vapor generating tubes and to each other as occasioned by the differential thermal expansion therebetween, said coupling means includinga guide member attached to each of said generating tubes so as to extend longitudinally thereof and inwardly into the space formed between said generating tubes to reduce the distance therebetween, a bracket connected to eachrof said vapor heating tubes on a portion thereof opposite the portion thereof tangent to the plane of said wall, and a tie means adapted to be slidably received in said brackets for maintaining said vapor heating tubes in coplanar alignment, said tie means including a bar means having shoulder portions to accommodate said. guide members for maintaining said aligned vapor heater tubes in position relative to said generating tubes.

6. In a vapor generating and heating unit, a tubular Wall defining a boundary portion of a furnace chamber, said tubular wall comprising a row of longitudinally extending vapor generating tubes arranged substantially tangent to the plane of said wall, a portion of some of the vapor generating tubes in said row being outwardly displaced out of the plane of said wall intermediate the length thereof to form a space between a pair of'vapor generating tubes extending in the plane of said wall, a plurality of vapor heating tubes extending longitudinally in said space between said vapor generating tubes, said vapor heating tubes being substantially tangent to the plane of said wall and supported in said space independently of said generating tubes, a detachable coupling means for maintaining said vapor heating tubes in relative coplanar alignment in the space formed between said pair of vapor generating tubes, said coupling means accommodating relative thermal expansion of said vapor generating and vapor-heating tubes, and said coupling means including aligned brackets connected to said vapor heating tubes, a tie bar extending transversely of said vapor heating tubes and slidably received in said brackets, and said tie bar having end shoulder portions arranged to abuttingly engage said spaced vapor generating tubes for maintaining said vapor heating tubes in alignment relative to each other and to said spaced vapor generating tubes.

7. In a vapor generating and heating unit, a tubular wall defining a boundary portion of a furnace chamber, said tubular wall comprising a row of longitudinally extending vapor generating tubes arranged tangent to the plane of said wall, a portion of some of the vapor gen erating tubes in said row being laterally displaced out of t the plane of said wall intermediate the length thereof to form a space between a pair of vapor generating tubes extending in the plane of said wall, said laterally displaced portion of the generating tubes extending longitudinally in a plane spaced from and substantially parallel to the plane of said wall outwardly of said chamber, a plurality of vapor heating tubes extending longitudinally in the space formed between adjacent pairs of spaced vapor generating tubes, said vapor heating tubes being substantially tangent to plane of said wall and supported in said space independently of said generating tubes, and readily removable coupling means for maintaining said vapor heating tubes in relative coplanar alignment in the space between said pair of vapor generating tubes, said coupling means accommodating for relative thermal expansion of said vapor generating and vapor heating tubes, said coupling means including a guide member longitudinally attached to the spaced pair of said generating tubes extending tangent to the plane of said wall, said guide means extending inwardly into the space formed between said pair of vapor generating tubes to reduce the distance therebetween, a plurality of C-shaped brackets, each of said brackets having opposed leg portions and a connected bight portion, and the leg portions of each of said C-shaped brackets being connected to one of said vapor heating tubes to form a closed loop there with, each of said brackets being connected in transverse alignment to a portion of said vapor heating tubes opportion tangent to said displaced tubes, and a second bar,

extending transversely of said loops and occupying the remainder of said loop, said second bar including an edge portion tangent to said vapor heating tubes. w 7

. References Cited in the file of this patent UNITED STATES PATENTS 1,802,750 Black -Q Apr. 28, 1931 2,228,953 Hackett Jan. 14, 1941 2,244,144 Drewry June 3, 1941 2,354,222 Shellenberger July 25, 1944 2,681,641 Andrew et a1. Iune 22, 1954 2,834,324

Schoessow May 13, 1958 myr-

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