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Патент USA US2116546

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May 10, 1938.
c. 5. SMITH
Filed March 29, 1935
3 Sheets-Sheet 1
Fig: 1'
20 700.
Charles S. Smz‘z‘h
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May 10, 1938.
c. s. SMITH
Filed March 29, 1935
5 Sheets-Sheet 2
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May 10, 1938.
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Filed March 29, 1935
3 Sheets-Sheet 5
Charles 5 Smii/z I
Patented May 10, 1938
Charles S. Smith,‘ West?eld, N. J ., assignor to
The Babcock & Wilcox Company, Newark, N. J .,
a corporation of New Jersey
Application March 29, 1935, Serial No. 13,694
3 Claims. (Cl. 122-480)
creased superheat, but this may be prevented,
and a constant superheat maintained, in the il
lustrative apparatus, by control of the ?ow of the
gases passing over the secondary section of the
It is an object of the invention to provide for
the regulation of superheat over a wide range
this control will now be described.
This invention relates to fluid heat exchange
apparatus, and it is exempli?ed herein as an em
bodiment of a water tube steam boiler with a
of boiler capacity.
It is an inherent characteristic ‘of some super‘
heaters that they produce a variable superheat
10 in response to changes in boiler ratings.
is particularly true of a superheater which is
mainly heated by convection transmitted heat.
This is an undesirable condition in modern
steam power plants, and it is a further object of
this invention to provide means for overcoming
this defect.
Other objects of the invention will appear in
the accompanying description of the superheater
boiler shown in the drawings, in which:
Fig. l is a view in the nature of a vertical sec
tion through the steam boiler and superheater
Fig. 2 is a view in the nature of a partial verti
cal section taken on the line 2-2 of Fig. 1.
Fig. 3 is an enlarged view in the nature of a
vertical section of part of the structure indicated
in Fig. 1.
Fig. 4 is a detailed vertical sectional view of a
part of the control mechanism, taken on the line
30 4-4 of Fig. 3.
In the drawings, there is shown a superheater
H) of the multiple loop type. It receives satu'
rated steam through the supply conduits l2 and
the inlet header I 4 from the steam and water
drum l6 of the boiler and is contacted by the fur
nace gases after they have passed across the
bank of horizontally inclined steam generating
tubes l8.
The boiler shown in the drawings is substan
tially a single pass boiler, whereas the superheater
may be said to- have a primary section and a sec
ondary‘section subject respectively to contact
with the furnace gases in di?erent gas passes.
The superheater baffle 20 separates these gas
superheater. The apparatus shown for elfecting
When boiler capacity increases, the gas de~
flector, shown as pivotally mounted at 26, may
be moved toward its dotted line position indi
cated in Fig. 3. Such action provides another
path for the gases leaving the first section and
one of less resistance than that across the sec
ond section. This reduces the ?ow of the gases
passing over the secondary section ofthe super
heater and tends to counteract the tendency of
the superheater to produce higher superheats
at increased boiler ratings when all of the gases
sweep its surface. It will be seen that, as the
de?ector 24 is moved toward its dotted line po
sition, more and more of the furnace gases may
pass directly to the outlet 25 without sweeping
over the secondary section of the superheater.
The de?ector 24 is controlled from a position
outside of the boiler setting, by a mechanism in
cluding a link 28 connected to an arm 30 which‘ 25
is non-rotatably mounted upon the shaft 32. The
shaft 32 is rotatably supported in bearings which
are preferably formed upon the casing 34. With
in the casing there is shown a worm wheel 36
?xed upon the shaft 32 and arranged to be driven 30
by a worm 38 journaled in the casing and having
a handwheel 40 ?xed thereto at its end.
The shaft 32 may, as indicated in Fig. 2, be
connected to extension shafts 42 and M so that
a number of the deflectors may be operated in 35
unison. Fig. 2 shows an illustrative construc
tion in which there are two control mechanisms,
each extending halfway across the boiler instal
Fixed to arms iii are counter-balancing
weights 48 which facilitate the operation of the
control mechanism.
As indicated in the drawings, the links 28 are
located between the horizontal circulators 50 and
52, and they pass through openings 5d and 56 pro
vided in the gas con?ning walls of the boiler.
At the left of the balile 20 shown in Fig. 1, . These openings ‘are wide enough to provide for
the swinging of the links 28 from their full line
the primary section of the superheater is sub
ject to contact with the furnace gases leaving positions to their dotted line positions as indi
cated in Fig. 3 of the drawings, and to maintain
the water tube bank I8. After the gases have
been progressively cooled by passing over the the opening 56 substantially closed during the 50
operation of the control mechanism, cover plates
tubes of this section they normally pass down
wardly at the rightof the baffle 20 and over the 58 are provided. These plates slide in guidewa-ys
provided by guides 68 and ,62, and are formed
secondary section 22 of the superheater.
As boiler ratings increase it is the tendency of with openings M through which the links 28 are
Ur in . superheaters located as here shown to‘ give in
passed. Indicia 66 provided upon the casing 34
coact with the indicators 68 to show the positions
of the superheat control mechanism.
the circulators 50 and 52. On the gas side of the
portion 84 of the circulator, the tubes of each of
When the de?ectors 24 are in their full line
these upright rows are bent so that they form a
single horizontal row of superheater tubes as in
positions indicated in Fig. 3, a maximum weight
of furnace gases passes over the secondary sec
dicated at I22.
tion 22 of the superheater. In this position the
de?ectors cooperate with end ba?‘les herein shown
continue in successively lower horizontal rows to
as plates ‘Ill secured to the superheater tubes or
loops. The major portion, and if desirable, all
10. of the furnace gases pass between the wall ‘H1 and
the ba?le 2d at low boiler ratings. The top of the
wall 10 is preferably below the top of the bank of
tubes Ii). Furthermore, it will be noted that the
control mechanism including the de?ectors 24
15 and the plates 10 are positioned in zones where
the gas temperature is lower than elsewhere. This
arrangement promotes the durability and long life
of the control apparatus by preventing excessive
The particular steam boiler shown has down
take headers ‘I2 connected at their lower ends
to a mud drum 14 and at their upper ends to the
water space of the drum I6 by downtake nipples
16 which are offset as indicated at 18 and 80 to
25 afford a minimum resistance to the passage of
gases to the outlet 25. The downtake headers are
connected to uptake headers 82 by the steam gen
erating tubes I8 and the former are connected at
their upper ends to the steam space of the drum
30 I6 by the horizontal circulators which have the
upright portions 84. These portions may be said
to be uptake nipples.
The uptake headers are
preferably pendently supported by hangers 86
Thence the superheater loops
the lowermost row I24 from which horizontal row
the tubes are bent to form vertical rows of tubes
I29 connected to the inlet headers I4.
The downtake headers of the boiler may be 10
pendently supported by the nipples 16 from the
drum I6 which is secured in a well known man
ner by strips secured to the structural frame
In order that the superheater tubes may be
subject to a desirable gas distribution and gas
contact, tile I31] are supported upon some of the
tubes and preferably positioned between the up
right rows which are spaced to accommodate the
tubes 94 and IE6.
The drum I6 may be supplied with feed water
in any suitable manner, and the outlet header
I I2 of the superheater may be appropriately con
nected to apparatus which makes use of the su
perheated steam.
The furnace has walls I32 and I33, the latter of
which includes wall cooling tubes I34 connected
into ?uid circulation by any suitable devices
which may include the upper header I36.
Not only does this invention involve means for 30
obtaining a close control of superheat over wide
temperature ranges, but it also accomplishes this
result with a minimum increase in draft when
?xed to the stationary frame structure 88.
As shown in Fig. l of the drawings some of the
the gases are directed over a second section of the
tubes of the uppermost row of steam generating
which is transverse to the tubes of the super
heater. The superheater is provided with two
sections with gas ?owing transversely across the
tubes in each section. A damper is provided
tubes leading from the downtake headers 12 are
connected at their upper ends to a header 90,
which is a support for the superheater and which
is preferably hung from an overhead beam by the
hangers 92 and the auxiliary circulators 94. The
latter may be connected to the drum 90 and be
positioned between upright rows of the super
heater tubes so as to afford an internal flow of
45 boiler water for protecting the baffle 95 against
overheating. At their discharge ends the circula~
tors 94 are connected with the steam space of the
Fig. 1 of the drawings shows a second super
heater supporting header Ill? connected by tubes
IE2 to the upper parts of the downtake headers
This is all done with a gas flow 35
which can be made to regulate the amount of gas 40
?owing over the second section. With this ar
rangement, at high loads, the gas bypasses the
second section giving a low draft loss through
the superheater. At the low loads, where excess
draft capacity is available, the gas is forced over 45
the second section to increase the superheat.
What is claimed is:
1. In a drainable super-deck superheater for
a single pass B. 86 W. boiler, a ?rst baiile extending
across the tubes of the superheater and separat- .
ing ?rst and second gas passes, a second ba?le
‘I2. Between the header I00 and the row of
downtake headers 12 a heat resisting inter-tube
space ?ller or superimposed layer IE4 is sup
supported by the superheater tubes in the second
gas pass and spaced from the ?rst baffle, and a
ported by the tubes I02 to form a wall which, in
this instance, causes all of the gases leaving the
bank of water tubes It to pass to the superheater.
This layer may consist of tile secured to the tubes
Above the header IIJIJ, wall 20 is cooled by sup—
plementary circulators IE6 preferably located be
tween upright rows of the superheater tubes and
connected at their lower ends to the header Ill.
Their upper ends I68 communicate directly with
the steam space of the drum I6 and hangers ID
are connected to the upper parts of these circu— ,.
?rst and second ba?‘les to limit the opening of the
second pass and to vary the total weight of the
gases contacting with the superheater tubes in
lators as shown.
tion of the gases contacting the second part of
the superheater in order to maintain constant
superheat when boiler ratings vary, said
Fig. 1 of the drawings also shows a superheater
outlet header H2 supported by hangers H4 de~
70 pending from the stationary structural member
H5 and communicating with the superheater
loops through outlet tubes I I8. These outlet
tubes as well as the inlet tubes I20 are indicated
as positioned in vertical rows with each row lo
75 cated between adjacent upright portions 84 of
manually operable damper co-operating with the
the second gas pass.
2. In apparatus of the class described, a steam
boiler including a furnace and a bank of steam
generating tubes, a single bank of superheater
tubes, ba?ies compelling the furnace gases to
pass over the generating tubes and a part of the
superheater in a single gas pass and then pass
over another part of the superheater in a second 65
gas pass, and means for varying only the propor
extend 70
through one of the baffles to form both super
heater parts.
3. In a steam boiler, steam generating tubes, a
bank of superheater tubes extending across the
path of the furnace gases at a position beyond the 75
steam generating tubes, a ba?‘le wall extending
across the superheater tubes and joined with a
second baf?e wall so extending from a side wall
of the furnace as to shield a part of the bank
gas de?ector means positioned beyond said re
mainder of the superheater and adjustable to
control superheat by decreasing the proportion
of the gases contacting with said part of the
from contact with the furnace gases until after ‘ superheater as the boiler load increases.
they have contacted the remainder thereof, and
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