U.S. patent number 3,665,893 [Application Number 05/102,346] was granted by the patent office on 1972-05-30 for vapor generator tube arrangement.
This patent grant is currently assigned to The Babcock & Wilcox Company. Invention is credited to Carl Lieb Barberton, Murray Wiener.
United States Patent |
3,665,893 |
Barberton , et al. |
May 30, 1972 |
VAPOR GENERATOR TUBE ARRANGEMENT
Abstract
A forced flow vapor generator wherein at least one of the
upright boundary walls of the furnace has a lower and upper section
formed of a first and second group of parallel flow tubes
respectively, the tubes in each group being rigidly united
throughout most of their lengths and having portions thereof
interlaced and coextensive with each other, the interlaced portions
being detached from one another for the most part. Provisions for
interconnecting the tubes of the first and second groups including
having inlet and outlet portions of the tubes bent out of the plane
of the wall, the bent out portions being detached from one another
for the most part.
Inventors: |
Barberton; Carl Lieb (Akron,
OH), Wiener; Murray (Akron, OH) |
Assignee: |
The Babcock & Wilcox
Company (New York, NY)
|
Family
ID: |
22289375 |
Appl.
No.: |
05/102,346 |
Filed: |
December 29, 1970 |
Current U.S.
Class: |
122/6A;
122/510 |
Current CPC
Class: |
F22B
37/66 (20130101); F22B 37/141 (20130101) |
Current International
Class: |
F22B
37/00 (20060101); F22B 37/14 (20060101); F22B
37/66 (20060101); F22b 037/24 () |
Field of
Search: |
;122/6A,235A,46S,46ST,510 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sprague; Kenneth W.
Claims
What is claimed is:
1. In a forced circulation fluid heating unit, upright walls
forming a furnace chamber, at least one of the walls including a
first group of upwardly extending laterally spaced fluid heating
tubes rigidly united throughout most of their lengths and forming a
lower portion of said one wall, a second group of upwardly
extending laterally spaced fluid heating tubes rigidly united
throughout most of their lengths and forming an upper portion of
said one wall, means for supplying fluid to the tubes of the first
group, header means communicating with and receiving and mixing
fluids flowing from the tubes of the first group and distributing
mixed fluids to tubes of the second group, some of the tubes of the
first and second groups being bent out of the plane of the wall at
first and second levels, respectively for connection to the header
means, and interlaced with each other in the plane of the wall
between the first and second levels, said first level being
subjacent the second level, the remainder of the tubes of the first
and second tube groups being bent out of the plane of the wall at
about the second and first levels, respectively, for connection to
the header means, the improvement comprising means for supporting
said one wall including support lugs weld united only to the
interlaced portions of the second group of tubes, means for
transmitting the load of the first group of tubes to the support
lugs, and means for top supporting the second group of tubes, the
tube portions in the plane of the wall in the vicinity of the first
and second levels and the interlaced portions therebetween being
detached from one another for the most part.
2. In a forced circulation fluid heating unit according to claim 1
wherein the means for transmitting the load of the first group of
tubes to the support lugs includes a plurality of plates, each
plate slidably engaged with at least one support lug and weld
united to oppositely adjacent interlaced tube portions of the first
group of tubes.
3. In a forced circulation fluid heating unit according to claim 1
wherein the means for supporting said one wall includes supported
lugs weld united only to the interlaced portions of the first group
of tubes.
4. In a forced circulation fluid heating unit according to claim 3
wherein said support lugs and supported lugs are vertically spaced
from one another in the plane of the wall.
5. In a forced circulation fluid heating unit according to claim 4
wherein the means for transmitting the load of the first group of
tubes to the support lugs includes plate means interposed between
said support lugs and supported lugs and slidably engaged
therewith.
6. In a forced circulation fluid heating unit according to claim 3
wherein each of said support lugs and supported lugs extends normal
to the plane of the wall and includes a base portion weld united to
a corresponding tube and a finger portion spaced from said tube to
provide a saddle therebetween.
7. In a forced circulation fluid heating unit according to claim 3
wherein said support lugs and supported lugs are tube-shaped.
8. In a forced circulation fluid heating unit according to claim 7
wherein each supported lug is superposed to the adjacent support
lug and is axially aligned therewith to form a common bore
therethrough, a pin extending through at least a major portion of
the bore and weld united to said supported lug.
9. In a forced circulation fluid heating unit according to claim 3
wherein said support lugs and supported lugs are in the form of
elongated fixtures extending parallel to and intersecting a plane
common to the longitudinal axes of the interlaced tube
portions.
10. In a forced circulation fluid heating unit according to claim 9
wherein the support lug and supported lug of adjacent tubes are
superposed in end-abutting relationship.
11. In a forced circulation fluid heating unit according to claim
10 wherein one of the abutting-ends is formed with a tongue portion
and the other abutting-end is formed with a grooved portion, said
abutting-ends being slidably engaged with one another.
12. In a forced circulation fluid heating unit, upright walls
forming a furnace chamber, at least one of the walls including a
first group of upwardly extending laterally spaced fluid heating
tubes rigidly united throughout most of their lengths and forming a
lower portion of said one wall, a second group of upwardly
extending laterally spaced fluid heating tubes rigidly united
throughout most of their lengths and forming an upper portion of
said one wall, means for supplying fluid to the tubes of the first
group, header means communicating with and receiving and mixing
fluids flowing from the tubes of the first group and distributing
mixed fluids to tubes of the second group, some of the tubes of the
first and second groups being bent out of the plane of the wall at
first and second levels, respectively, for connection to the header
means, and interlaced with each other in the plane of the wall
between the first and second levels, said first level being
subjacent the second level, the remainder of the tubes of the first
and second tube groups being bent out of the plane of the wall at
about the second and first levels, respectively, for connection to
the header means, and means for supporting said one wall including
support lugs weld united only to the second group of tubes and
supported lugs weld united only to the first group of tubes, means
for transmitting the load of the first group of tubes to the
support lugs, and means for top supporting the second group of
tubes, the tube portions in the plane of the wall in the vicinity
of the interlaced portions therebetween being detached from one
another for the most part.
13. In a forced circulation fluid heating unit according to claim
12 wherein some of said support lugs are weld united to the
interlaced portions of the second group of tubes and the remaining
support lugs are weld united to the second group of tubes entering
the plane of the wall at the second level, and some of said
supported lugs are weld united to the first group of tubes leaving
the plane of the wall at the first level and the remaining
supported lugs are weld united to the interlaced portion of the
first group of tubes, the means for transmitting the load of the
first group of tubes to the support lugs including separate plate
means slidably engaged with the support lugs and supported lugs and
means for interconnecting said plate means.
14. In a forced circulation fluid heating unit according to claim
13 wherein the means for interconnecting said plate means includes
a plurality of support bars having end portions extending over at
least a portion of the plate means and being weld united thereto.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to the construction of a forced
flow fluid heating unit, and more particularly to improvements in
the construction and arrangement of the furnace fluid heating
circuits of a forced circulation oncethrough steam generating and
superheating unit.
The present invention is directed to improvements in the furnace
fluid heating circuitry of a forced flow vapor generator of the
type disclosed in U.S. application Ser. No. 447,699 wherein the
upright boundary walls of the furnace are subdivided into a
plurality of separate continuous upflow fluid heating passes with
the parallel flow tubes of one of the fluid heating passes being
interlaced and coextensive with the parallel flow tubes of another
of the heating passes, and with special provisions for supporting
and interconnecting the tubes of the fluid heating passes to
provide a serial flow of fluid successively through the respective
fluid passes to equalize fluid enthalpies as they flow from one
furnace heating pass to another.
In furnace walls of prior units of the character described,
portions of tubes of the separate heating passes form a common
plane wherein they are interlaced and coextensive, and above and
below this common plane, the tubes are bent outwardly of the plane
of the wall and connected to suitably arranged headers. Laterally
adjacent tubes are rigidly united to one another by metallic webs
above and below the interlaced area and the point at which the
tubes are bent outwardly from the plane of the wall. The intertube
spacing at the point where the tubes leave the plane of the wall
and at the interlaced and coextensive portions has been closed by
seal plates welded to laterally adjacent tubes, however, due to the
expansion and contraction of the wall during the heating and
cooling of the unit, excessive stresses are created by these seal
plates frequently resulting in cracking of the plates or tubes.
SUMMARY OF THE INVENTION
In accordance with the present invention, the forced circulation
fluid heating unit comprises upright walls forming a furnace for
heating gases, with at least one of the walls including a first
group of upwardly extending laterally spaced fluid heating tubes
rigidly united by metallic webs throughout most of their length to
for a lower portion of the wall, and a second group of upwardly
extending laterally spaced fluid heating tubes rigidly united by
metallic webs throughout most of their lengths to form an upper
portion of the wall. Headers are provided for receiving and mixing
fluid flowing from the tubes of the first group and distributing
the fluids to the tubes of the second group. Some of the tubes of
the first and second tube groups are bent out of the plane of the
wall at first and second levels, respectively, for connection to
the headers and interlaced with and laterally spaced from each
other in the plane of the wall between the first and second levels,
with the first level being subjacent the second level, the
remainder of the tubes of the first and second tube groups being
bent out of the plane of the wall at about the second and first
levels, respectively, for connection to the header means. An
arrangement for supporting the wall including support lugs weld
united only to the interlaced portions of the second group of
tubes, means for transmitting the load of the first group of tubes
to the support lugs, and means for top supporting the second group
of tubes, the tube portions in the plane of the wall in the
vicinity of the first and second levels and at the interlaced
portions therebetween being detached from one another for the most
part. An alternate arrangement with provisions for supporting the
wall including support lugs weld united only to the second group of
tubes and supported lugs weld united only to the first group of
tubes, means for transmitting the load of the first group of tubes
to the support lugs, and means for top supporting the second group
of tubes, the tube portions in the plane of the wall in the
vicinity of the interlaced portion therebetween being detached from
one another for the most part.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional side elevation of a once-through forced flow
steam generator embodying the invention;
FIG. 2 is an enlarged sectional side view of a portion of the fluid
collection, mixing and distribution system of the front wall shown
in FIG. 1;
FIG. 2A is a sectional plan detail view along line 2A--2A of FIG.
2;
FIG. 3 is a sectional front detail view of an embodiment of the
invention also shown in FIG. 2;
FIG. 3A is a sectional side detail view taken along line 3A--3A of
FIG. 3;
FIG. 4 is a sectional front detail view of an alternate embodiment
of the invention;
FIG. 4A is a sectional side detail view taken along line 4A--4A of
FIG. 4;
FIG. 5 is a sectional front detail view of a further alternate
embodiment of the invention.
FIG. 5A is a sectional side detail view taken along line 5A--5A of
FIG. 5;
FIG. 5B is a sectional plan view taken along line 5B--5B of FIG.
5;
FIG. 6 is still a further alternate embodiment of the
invention;
FIG. 6A is a detail view of the juncture of the superposed lugs
shown in FIG. 6;
FIG. 6B is a sectional plan detail view taken along line 6B--6B of
FIG. 6A;
FIG. 6C is a detail view of the juncture of the superposed lugs
taken along line 6C--6C of FIG. 6B;
FIG. 7 is a sectional front detail view of still another embodiment
of the invention;
FIG. 7A is a sectional side detail view taken along line 7A--7A of
FIG. 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, the invention has been illustrated as embodied in
a top-supported forced flow one-through steam generator intended
for central station use.
The main portions of the unit as illustrated in FIG. 1, include an
upright furnace chamber 10 of substantially rectangular horizontal
cross-section defined by front wall 11, rear wall 13, side walls
14, a roof 16 and a hopper 17 and having a gas outlet 18 at its
upper end opening to a horizontally extending gas passage 19 of
rectangular vertical cross-section formed by a floor 21 and
extensions of the furnace roof 16 and side walls 14. Gas passage 19
communicates at its rear end with the upper end of an upright gas
passage 22 of rectangular horizontal cross-secton formed by a front
wall 23, a rear wall 24, side walls 26, and an extension of the
roof of the gas passage 19.
The fuel firing section comprises vertically spaced rows of burners
27 disposed on opposite walls 11 and 13 at the lower portion of the
furnace chamber 10.
The gas passage 19 is occupied by a secondary superheater 28 and a
reheater 29 arranged in series with respect to gas flow while gas
passage 22 is occupied in the direction of gas flow by a primary
superheater 33 and an economizer 34.
In the normal operation of the fluid heating unit, combustion air
and fuel are supplied to the burners 37 and the fuel is burned in
the lower portion of the furnace. Heating gases flow upwardly
through chamber 10 to the furnace outlet, thence to gas passage 19
and then pass successively over and between the tubes of secondary
superheater 28 and reheater 29 in gas passage 19 and over and
between the tubes of primary superheater 33 and economizer 34 in
gas passage 22, and discharge to another heat trap, not shown,
before entering to the stack, now shown. It will be understood that
in accordance with well-known practice, each of the superheater and
reheater sections extend across the full width of its corresponding
gas passage and is formed for serial flow of steam by multiple
looped tubes.
The vapor generating system is top supported by structural members
including upright members 85 and cross beams 90, from which hangers
95, of which only a few are illustrated support all walls and
convection surfaces.
Feedwater at high pressure is supplied by a feed pump, not shown,
to economizer inlet header 25, then passes through economizer 34 to
outlet header 30, from which it flows through a downcomer 35 for
flow to the furnace boundary wall fluid heating circuitry.
Each of the upright boundary walls of the furnace and gas passages
19 and 22 are of gas tight construction and include parallel tubes;
front wall 23 having tubes 71 extending between inlet and outlet
headers 72 and 73, rear wall 24, having tubes 74 extending between
inlet and outlet headers 76 and 77, each side wall 26 having tubes
78 extending between inlet headers 79 and 83 and outlet headers 81
and 84. Floor 21 is formed by a row of tubes 86 having their inlet
ends connected to header 52 and their outlet ends to header 73,
with header 73 being connected for fluid flow to header 88 by a row
of screen tubes 89. Headers 72, 76, 79 and 83 are connected for
parallel supply of fluid from a conduit 69, while headers 77, 81,
84 and 88 are arranged for discharge to another collector header
91, from which fluid passes to the primary superheater via conduit
92 and inlet header 52. From primary superheater 33, the partly
superheated vapor passes through an outlet header 55 and in through
inlet header 57 to the secondary superheater 28, within which the
vapor receives its final superheating before passing through an
outlet header 59 to a high pressure turbine, not shown. Partially
expanded steam from the high pressure turbine passes through
reheater 29, and from thence to the reheat pressure turbine wherein
final expansion takes place.
Each of the upright boundary walls of furnace 10 is formed by
upwardly extending parallel tubes arranged to provide two upflow
fluid heating passes and having their intertube spacing closed
throughout most of their length by metallic webs welded to adjacent
tubes to provide a gas-tight construction. The first heating pass
comprises the first group of tubes and forms the lower portion of
each furnace wall and the second fluid heating pass comprises the
second group of tubes and forms the upper portion of each furnace
wall. Special header provisions are made for mixing the heat
absorbing medium intermediate its flow from one pass to another,
the mixing system from each of the fluid heating passes being
specifically for the purpose of keeping the wall tube temperature
differentials across the width of the furnace wall panel to a
minimum. With differences in furnace cleanliness as well as in the
flow rates in the multiple parallel fluid flow paths it is possible
to develop temperature differences between adjacent tubes of a
magnitude sufficient to induce high stresses in the tubes and in
the metallic webs therebetween. By limiting the total absorption in
a furnace heating pass, the degree of thermal imbalance within the
tubes comprising the parallel flow paths is also limited.
Accordingly, the boundary wall of the furnace is designed so that
the temperature at a particular level of furnace height or
elevation differs by no more than a predetermined value from the
calculated average fluid temperature of all furnace wall tubes at
that level; thus calculated maximum temperature differential
between adjacent tubes is below the predetermined critical limit to
minimize fluid flow imbalances; and so that the tubes of each fluid
heating pass are sufficient in flow area to provide an adequate
circulation rate. Further, all heated tubes of the furnace boundary
walls are arranged for upflow of fluid, since flow stability within
heating passes having their tubes so arranged is markedly improved
over that condition where flow circuitry has heated downflow as
well as upflow tubes. In other words, flow imbalances for the same
average and unbalanced heat absorption conditions are considerably
less severe with all upflow tubes than with both upflow and
downflow circuitry within a heat absorbing zone.
The front wall 11 comprises first pass upflow tubes 37A, 37A' and
second pass upflow tubes 37B, 37B'. Rear wall 13 includes first
pass upflow 38A, 38A' and second pass upflow tubes 38B, 38B' with
the second pass tubes forming a screen extending through gas
passage 19 and the remainder forming a nose arch 41. Each side wall
14 includes first pass upflow tubes 39A, 39A' and second pass
upflow tubes 39B, 39B'.
First pass upflow 37A, 37A', 38A, 38A', 39A, 39A' of the front,
rear and side walls of furnace 10 have their inlet ends connected
to inlet headers 44 associated with the corresponding walls and
their upper ends connected to intermediate outlet headers 49
associated with the corresponding walls. Inlet headers 44 are
supplied with fluid from conduit 35. Fluid passing through first
pass upflow tubes 37A, 37A', 38A, 38A', 39A, 39A' is collected in
intermediate or first pass outlet headers 49 and then passed
through conduit 51 to second pass inlet headers 52 arranged to
supply fluid to second pass upflow tubes 37B, 37B', 38B, 38B', 39B,
39B'. The second pass upflow tubes extend from inlet headers 52,
associated with the corresponding walls, to the top of the furnace,
tubes 37B, 37B' having their discharge ends connected to second
pass outlet header 53, some of the tubes 38B, 38B' having their
discharge ends connected to screen tube inlet header 73 and the
remainder to screen tube outlet header 88, and tubes 39B, 39B'
having their discharge ends connected to headers 63. The fluid
discharges from headers 53 and 63 flow through the tubes forming
the roof 16 and thereafter into the conduit 69.
From the above description it is evident that tubes 37A, 37A', 38A,
38A', 39A, 39A' constitute the first fluid heating pass of the
furnace, and tubes 37B, 37B', 38B, 38B', 39B, 39B' the second fluid
heating pass. The tubes of the first heating pass are substantially
coextensive within each respective wall and have their intertube
spaces closed by metallic webs 103, weld-united to the tubes along
substantially their entire parallel lengths. Tubes of the second
fluid heating pass, with the exception of screen tubes, have their
intertube spaces closed by metallic webs 104, weld-united to the
tubes along substantially their entire lengths. Tubes of the second
fluid heating pass of each upright wall, except for the rear wall
of the furnace, are coplanar along almost their entire length
within their respective walls and are also coplanar with the tubes
of the associated first fluid heating pass of the corresponding
wall.
Since the construction and arrangement of the fluid collection,
mixing and distribution systems and their associated tubes are
substantially the same in all walls, it will suffice to describe
the front wall system fluid heating passes.
Referring to FIG. 2 there is shown a sectional side view of a
portion of the fluid collection, mixing and distribution system of
the front wall wherein the discharge portion of the first pass
tubes 37A are bent outwardly from the plane of the wall 11 at the
first level 101 and then extend horizontally and downwardly for
radial connection to first pass outlet header 49. The discharge
portions of the first pass tubes 37A' are bent outwardly from the
plane of the wall 11 at about the second level 102A and extend
horizontally and downwardly for radial connection to first pass
outlet header 49. The fluids discharged from the first heating pass
tubes 37A, 37A', also referred to as the first group of tubes, are
collected and mixed in the header 49 to neutralize the differences
in amount of heat picked up before being passed to the second pass
inlet header 52 via exterior conduits 51 for uniform distribution
to the parallel flow tubes 37B, 37B', also referred to as the
second group of tubes, and comprising the front wall second fluid
heating pass. Inlet portions of the second pass tubes 37B extend
from inlet header 52 radially inward and then bend upwardly to
enter the front wall 11 at about the first level 101A from whence
they extend upwardly in the plane of the wall and in contiguous
relation with the adjacent portions of the first pass tubes 37A'.
Inlet portions of the second pass tubes 37B' extend radially
outward, vertically, then horizontally and then bend upwardly to
enter the front wall 11 at the second level 102 from whence they
extend upwardly and in contiguous relation with the second pass
tubes 37B which entered the plane of the wall at the about level
101A. Metallic webs 103 close the spaces between the first pass
tubes 37A, 37A' up to the first level 101, while metallic webs 104
close the spaces between the second pass tubes 37B, 37B' above the
second level 102. The wall intertube spaces intermediate the first
and second levels are partially closed by metallic fin plates 105
except at the points where tubes 37A, 37A', 37B, 37B' bend out of
the plane of the wall. Closure is provided at these points by
metallic scalloped plates 106 suitably shaped to fit the bent tube
portions. Metallic supported lugs 108 are welded to the interlaced
portions of the first heating pass tubes 37A' which are part of the
first group of tubes, and the support lugs 107 are welded to the
interlaced portions of the second heating pass tubes 37B which are
part of the second group of tubes. An elongated flat metal plate
109 lies contiguous to the wall 11 and extends across the width of
the wall and is interposed between and slidably engaged with the
support and supported lugs 107 and 108, respectively, to transmit
the load of the first group of tubes to the second group of tubes.
A wall box 99, formed by a welded metal casing 111 and including a
suitable refractory material 112, provides a gas-tight seal for the
detached tube area existing between the levels 101 and 102.
Thus at the locations where mixing of the fluids occurs as they
flow from one furnace fluid heating pass to another, the interlaced
tube portions of the first and second heating passes as well as the
points where the tubes of both these heating passes bend out of the
plane of the wall, are detached from one another with the first
pass heating tubes forming the lower portion of the wall and being
connected for support by the second pass heating tubes through a
slidable support arrangement capable of absorbing the expansion and
contraction of the tube wall during the heating and cooling of the
unit.
Referring to FIG. 2A there is shown a sectional plan detail view of
some of the interlaced tube portions of front wall 11 depicting
first and second pass heating tubes 37A' and 37B with their
intertube spacing partially closed by the fin plates 105 and backed
by a suitable refractory 112 to form a gas-tight seal.
Referring to FIGS. 3 and 3A there are shown sectional front and
side detail views, respectively, taken at the interlaced tube
portions and depicting an embodiment of the invention including a
section of the elongated metal plate 109 lying contiguous to a
section of the interlaced first and second pass tube portions 37A'
and 37B. The support lugs 107 are formed with a base portion 107A
and a finger portion 107B and have the base portion welded to the
interlaced portion of the second pass tubes 37B. The supported lugs
108 are formed with a base portion 108A and a finger portion 108B
and have the base portion welded to the interlaced portion of the
first pass tubes 37A'. Top and bottom sections of metal plate 109
are interposed between the support lugs and slidably engaged
therewith. The intertube spacing between the interlaced tube
portions is partially closed by the fin plates 105 and the spacing
between the levels 101 and 101A is partially closed by the
scalloped plates 106. The intertube spaces below the level 101
where the tubes 37A leave the plane of the wall are closed by
metallic webs 103.
The metallic fin plates 105 are arranged in rows disposed on
opposite sides of the interlaced tube portions and welded thereto.
One typical arrangement calls for two rows of plates spanning the
intertube spacing, each row being associated with one of two
adjacent tubes and including fin plates 105 measuring 1 to 3 inches
in length and spanning nearly one-half the width of the intertube
spacing, the fin plates being serially spaced one-sixteenth to
one-fourth inches and the adjacent rows being laterally spaced
one-sixteenth to one-fourth inches. Another arrangement has the fin
plates spanning nearly the entire width of the intertube spacing
and forming a single row welded to only one of two adjacent tubes.
Still another arrangement has fin plates spanning nearly the entire
width of the intertube spacing and forming two intermeshed rows
whereby alternate fins are welded to the other of two adjacent
tubes. These latter two arrangements which are not shown in the
drawings are also serially and laterally spaced in the range of
one-sixteenth to one-fourth inches. The scalloped plates 106
consist of two plates having adjacent sides shaped to fit the
contour of the tubes as they bend out of the plane of the wall and
having their opposite sides welded to adjacent interlaced tube
portions.
The weight-load of the first pass tubes 37A is transmitted to the
first pass tubes 37A' through the metallic webs 103. The combined
weight-load of the lower portion of the furnace as represented by
tubes 37A and 37A' is transmitted through the supported lugs 108,
associated with tubes 37A' to the elongated metal plate 109 which
in turn transmits the lower furnace portion weight-load to the
support lugs 107 associated with the second pass tubes 37B, the
latter together with the second pass tubes 37B' form the upper
portion of the furnace. The weight-load transmitted through the
lugs 107 is partially taken-up by the tubes 37B with the rest being
passed to the tubes 37B' through the metallic webs 104. The tubes
37B and 37B' attach to a fluid discharge header 53 which is
connected by hangers 95 for support by upright members 85 and cross
beams 90. The wall arrangement thus provided is capable of
absorbing the expansion and contraction of the tube sections at the
interlaced portion by leaving each of the support lugs 107 and the
corresponding supported lug 108 free to move independently of one
another along the bar 109.
Referring to FIGS. 4 and 4A there are shown sectional front and
side detail views, respectively, taken at the interlaced tube
portions and depicting an alternate embodiment of the invention
including a plurality of plates 110 lying contiguous to a section
of the interlaced first and second pass tube portions 37A' and 37B.
Each of the plates 110 being of rectangular shape and sized to
cover a section of a corresponding interlaced portion of second
pass tube 37B and to overlap sections of the oppositely adjacent
interlaced portions of first pass tubes 37A'. Each upright side of
the plate 110 is welded to the corresponding overlapped section of
first pass tube 37A'. The support lugs 107 are welded to the second
pass tubes 37B and are arranged to slidably engage a bottom section
of a corresponding plate 110. The intertube spacing between the
interlaced tube portions is partially closed by the fin plates 105
which are fully set forth in the description of FIGS. 3 and 3A.
The weight-load of the lower portion of the furnace is transmitted
through the individual plates 110 associated with the first pass
tubes 37A' to the support lugs 107 associated with the second pass
tubes 37B, these latter tubes are part of the upper portion of the
furnace wall which is connected for support to the structural steel
supporting the vapor generating system. The wall arrangement thus
provided allows each of the plates 110 and the corresponding
support lug 107 to move independently of one another.
Referring to FIGS. 5, 5A and 5B there are shown sectional front,
side and plan detail views, respectively, taken at the interlaced
tube portions and depicting an alternate embodiment of the
invention including tube-shaped support lugs 121 and tube-shaped
supported lugs 122. Each support lug 121 is welded along its axial
length to a section of a corresponding interlaced portion of a
second pass tube 37B and each supported lug 122 is welded along its
axial length to a section of a corresponding interlaced portion of
a first pass tube 37A'. There are two support lugs associated with
each tube 37B and two supported lugs associated with tube 37A'. The
support and supported lugs extend outwardly of the plane of the
wall in a radial direction so as to overlap the adjoining intertube
spacings and each supported lug 122 is superposed to the adjacent
support lug 121 and is axially aligned therewith to form a common
bore therethrough. A pin 113 is slidably fitted through the bore
and extends slightly beyond the ends of the bore. The upper end of
pin 113 is welded to a portion of the top cross-sectional surface
of supported lug 122. The support lug 121 remains free to move with
respect to the pin 113. The intertube spacing between the
interlaced tube portions is partially closed by the fin plates 105
which are fully set forth in the description of FIGS. 3 and 3A.
The weight load of the lower portion of the furnace is transmitted
through the support lugs 122 associated with the first pass tubes
37A' to the support lugs 121 associated with the second pass tubes
37B, these latter tubes are part of the upper portion of the
furnace wall which is connected for support to the structural steel
supporting the vapor generating system. The wall arrangement thus
provided allows each of the support lugs 121 and the corresponding
support lug 122 with its attached pin 113 to move independently of
one another.
Referring to FIGS. 6, 6A, 6B and 6C there are shown sectional
front, side and plan detail views, respectively, taken at the
interlaced tube portions and depicting a further alternate
embodiment of the invention including support lugs 114 and
supported lugs 115 in the form of elongated fixtures extending
parallel to and intersecting a plane common to the longitudinal
axes of the interlaced tube portions. Each support lug 114 is
welded along its axial length to a section of a corresponding
interlaced portion of a second pass tube 37B and each supported lug
115 is welded along its axial length to a section of a
corresponding interlaced portion of a first pass tube 37A', there
are two support lugs associated with each tube 37B and two
supported lugs associated with each tube 37A'. Each supported lug
115 is superposed to the adjacent support lug 114 with the abutting
ends being slidably engaged to one another. The abutting end of
each support lug 115 is formed with a grooved portion 115A sized to
slidably accommodate a tongue portion 114A formed on the abutting
end of each support lug 114. The intertube spacing between the
interlaced tube portions is partially closed by the fin plates 105
which are fully set forth in the description of FIGS. 3 and 3A.
The weight of the lower portion of the furnace is transmitted
through the supported lugs 115 associated with the first pass tubes
37A' to the support lugs 114 associated with the second pass tubes
37B, these latter tubes are part of the upper portion of the
furnace wall which is connected for support to the structural steel
supporting the vapor generating system. The wall arrangement thus
provided allows the support lug 115 and the corresponding support
lug 114 to move independently of one another.
Referring to FIGS. 7 and 7A there are shown sectional front and
side detail views, respectively, taken at the interlaced tube
portions and depicting still another embodiment of the invention
including the discharge portions of first pass tubes 37A which are
bent outwardly from the plane of the wall 11 at the first level 101
for connection to the first pass outlet header 49 (not shown). The
discharge portions of the first pass tubes 37A' are bent outwardly
from the plane of the wall 11 at about the second level 102A for
connection to first pass outlet header 49 (not shown). The inlet
portions of the second pass tubes 37B extend from the second pass
inlet header 52 (not shown) and bend upwardly to enter the front
wall 11 at about the first level 101A from whence they extend
upwardly in the plane of the wall and in contiguous relation with
adjacent portions of the first pass tubes 37A'. Inlet portions of
the second pass tubes 37B' extend from the second pass inlet header
52 (not shown) and bend upwardly to enter the front wall 11 at the
second level 102 from whence they extend upwardly and in contiguous
relation with the second pass tubes 37B which entered the plane of
the wall at the about level 101A. The supported lugs 108 are welded
to the first pass tubes 37A at a location subjacent to the level
101 and to the interlaced portions of the first pass tubes 37A' at
a location subjacent to the about level 102A. The support lugs 107
are welded to the interlaced portions of the second pass tubes 37B
at a location superjacent to the about level 101A and to the second
pass tubes 37B' at a location superjacent to the level 102.
Elongated flat metal plates 116A, B, C and D are substantially
equal in size and disposed in contiguous relationship to a section
of wall 11 and have their longitudinal extent lying across the
width of the wall. A top section of plate 116A is slidably engaged
with the supported lugs 108 attached to the tubes 37A. A bottom
section of plate 116B is slidably engaged with the support lugs 107
attached to the tubes 37B. The plates 116A and 116B are
interconnected by support bars 117 which have their respective end
portions extending across the width of these plates and are welded
thereto. A top section of plate 116C is slidably engaged with the
support lugs 108 attached to the tubes 37A'. A bottom section of
plate 116D is slidably engaged with the support lugs 107 attached
to the tubes 37B'. The plates 116C and 116D are interconnected by
support bars 117 in like manner to the interconnection of plates
116A and 116B. The intertube spacing between the interlaced tube
portions is partially closed by the fin plates 105 and the spacing
between the levels 101 and 101A and between the levels 102 and 102A
is partially closed by the scalloped plates 106. The intertube
spaces below the level 101 where the tubes 37A leave the plane of
the wall are closed by metallic webs 103 and the intertube spaces
above the level 102 where the tubes 37B' enter the plane of the
wall are closed by metallic webs 104. The aforementioned plates are
fully set forth in the description of FIGS. 3 and 3A.
The weight-load of the first pass tubes 37A is transmitted through
the support lugs 108, associated with the tubes 37A, to the plate
116A which is in turn supportingly connected to the plate 116B by
way of the support bars 117 associated therewith. The plate 116B
transmits this weightload to the tubes 37B through the support lugs
107 associated with the tubes 37B. The weight-load of the tubes
37A' is transmitted through the support lugs 108, associated with
the tubes 37A', to the plate 116C which is in turn supportingly
connected to the plate 116D by way of the support bars 117
associated therewith. The plate 116D transmits this weight-load to
the tubes 37B' through the support lugs 107 associated with the
tubes 37B'. The tubes 37B and 37B' form the upper portion of the
furnace wall which is connected for support to the structural steel
supporting the vapor generating system. The wall arrangement thus
provided allows each of the support lugs 107 and corresponding
support lugs 108 free to move independently of one another.
* * * * *