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Патент USA US2104937

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Jall- 11, 19358»l
c. s. TURNER
Filed sept. fr, 1934
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Jan. 11, 1938.
Filed Sept. 7, 1934
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Jan. 11, 1938.
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Filed Sept. 7, 1934
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Patented Jan. 11, 1938
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Charles S. Turner, Detroit, Mich.
Application September 7, 1934, Serial No. 743,068
8 Claims. (Cl. 122-481)
This invention relates to boiler superheaters,
A further object contemplated by this inven
and incorporates amo-ng its particular objects im
tion is the provision of a novel water-regulated
provement of superheaters of the varieties dis
radiant superheater adapted for use in locomo
closed in my copending applications Serial Nos.
tive boilers and of very compact construction, in
e: ;.- 496,868, filed November 20, 1930, “Superheater
which no steam inlet connections to the super 5
construction”; 512,675, ñled January 31, 1931, heater or discharge connections for the cooling
“Superheater construction”; 534,490, filed May 2, water channels, or headers for these portions,
1931, “Fluid cooled superheatei` construction”; need be located outside the boiler itself, and in
590,108, ñled February 1, 1932, “Superheater as
which the superheated steam is discharged at a
' l'. sembly”; and 699,541, ñled November 24, 1933,
“Superheater construction”.
A further aim of the present invention is to
provide an improved superheater particularly
suited for installation in fire tube boilers of the
-»' .f locomotive type.
It has been the common prac
tice, in the installation of superheaters in such
boilers, to place superheating elements in certain
of the lire tubes, which are enlarged to receive
Such superheaters work by convection,
and since they are not exposed to radiant heat,
and since the rate of possible heat absorption is
very much less when convection is relied upon, a
relatively very large superheating surface must
be used, and this method of installing the super
»„. heater elements accordingly detracts from the
efûciency of the boiler by unduly reducing the
number of ñre tubes eiïective to assist in steam`
generation. My invention therefore also compre
hends so installing a superheater in such boilers as
to offer no material obstruction to or reduction
ofthe effective number of ñre tubes.
Still another object is the development of a
superheater installation having an active portion
disposed directly within the fire box of such a fire
i. tube boiler at a point subjecting it to radiant heat
at a relatively higher temperature than the tubes
could withstand if empty, and the componentY
units of which are so operated and designed as to
be guarded against damage by overheating when
empty of steam.
Still further my present invention aims to so
arrange a water cooled superheater within the fire
box of a ñre tube boiler as to provide a support
for baffling means calculated to increase the
length of the path of gases of combustion andv
flame travel, and to replace or partly replace the
conventional water tubes now ordinarily employed
for that purpose.
Yet another object is the provision of an im
ì proved structural arrangement of such a super
heater _in a ñre tube boiler, in which the com
ponent superheater elements project through leg
Vwaiter walls of the boiler which form the ñre box,
yet are so arranged as to reinforce and strengthen
Cil ' .j the leg walls.
point so close to its destination as to enable the
use of even shorter steam pipes than are em.
ployed in a non-superheated locomotive boiler.
Other objects and advantages will be apparent
from the following description, wherein reference
is made to the accompanying drawings illustrat- `
ing preferred embodiments of my invention and
wherein similar reference numerals designate
similar parts throughout the several views.
In the drawings:
Figure l is a somewhat simplified and diagram
matic vertical section of the fire boX and adjacent
rear portions of a ñre tube locomotive boiler,
showing an illustrative installation of one of my
improved water regulated superheaters.
Figure 2 is a plan view of the superheater as
sembly, taken substantially on the line 2_2 of
Figure l and looking in the direction of the ar
rows, partly broken away and with the boiler and
baiiling arch portions omitted to añord a better
view of the superheater.
Figure 3 is an enlarged transverse section of a
header and the extremities of one tube assembly,
taken substantially on the line 3_3 of Figure 2
and looking in the direction of the arrows.
Figure 4 is a cross section of a tube assembly
taken substantially on the line 4_4 of Figure 2
and looking in the direction of the arrows.
Figure 5 is a longitudinal sectional elevation of
a locomotive boiler construction equipped with a
superheater incorporating my invention in some 40
what modiñed form.
Figure 6 is a horizontal detail section taken sub
stantially on the line 6_6 of Figure 5 and looking
in the direction of the arrows, and
Figure 7 is a view similar to Figure 4 of a modi
ñed tube assembly.
Referring now to the drawings, and particularly
first to Figure 1, which will be seen to illustrate
somewhat conventionally the rear portions of a
locomotive boiler typical in many respects, refer
ence character I 0 designates the main shell, from
which the crown sheet I2 is supported in the
usual or any desired manner, as by crown stays
I 4, to define a ñre box I5. Forwardly from the
fire box projects the main boiler section I6, con
taining íire tubes, as Il, while leg Walls, as 20-2 I ,
jacket the ñre box, the leg 2t constituting a down
ward extension of the front Wall, while the leg 2|
defines the rear wall of the iire box; all in known
It is desirable'that a bañiing arch, as 2l2, of
ñre brick or the like, be supported in such posi
tion within the fire box as to force the burning
and burned gases to double back and pass there
10 around. Such arches' have in the past been car
ried by water cooled supports constituting water
tubes connected to the iront and rear leg walls
and serving to assist in steam generation. Steam
generated in such water tubes, of which there
15 are ordinarily not more than five or six, is de
livered, in the conventional constructions re
ferred to, into the main boiler I6, and collected
with the remainder of the steam developed in the
boiler in a steam dome as 25, whence it was
20 either conducted through a dry pipe and‘to the
cylinders or delivered to a superheater of one of
the types previously used, ordinarily housed with
in certain of the fire tubes, as stated.
In carrying out my »invention` I replace both
25 of the usual elements last discussed, that is the
superheater units within the fire tubes and the
water tube arch supports, by water regulated
superheater assemblies each consisting of a cen
tral Water conduit portion 30 and a plurality of
30 circumferentially disposed steam tubes 313 as
sembled and contoured in the manner indicated
in Figures 2, 3 and 4. As shown -in Figures 3
and 4, the central water tube 3B is preferably
provided with a smoothly cylindrical interior sur
35 face to facilitate cleaning, while its external sur
face is provided with flutes defined by radially
projecting ribs 35. The ribs are preferably heli
cally disposed about Vthe >exterior of the tube as
shown in Figures 1 and 2, and the channels be
40 tween the ribs are curved conformably to the
radius of the steam tubes 33, which are ñtted
thereinto and welded in place, as at 36.
-A plurality of such water cooled superheater
conduit assemblies, five being shown, are extend
45 ed across the rire box, preferably from front to
back and at an angle to the horizontal, each as
the open ends of the extensions 3l, so that the
latter open thereinto, the water header being
welded to the steam header along its edges as
at 45 to form a semi-cylindrical enclosure.
Steam header 42’ constitutes the inlet for Ysteam
to be superheated, which is delivered thereinto
through a dry pipe lill from the steam dome 25.
The dry pipe may, as shown, beV projected
through the boiler between the main shell and
the crown sheet and connected to the steam in 10
let header 42’ at the rear of the boiler. The
cooling water is preferably fed to the assembly
through a take off pipe til, tapped into the bot
tom of the boiler and connected to Water inlet
header 44, while the offtake 48 delivers water 15
and steam generated in the water tubes from
outlet Water header 44’ to the boiler, within and
near the top `of which it discharges, as shown in
`Figure l. From the steam outlet header 42 a
pipe, as 5i), may conduct the superheated steam 20
to the cylinders (not shown) or other destina
The inflow of cooling vwater is preferably
throttled by means of an inlet valve, as 52,
adapted to so regulate the admission of Water 25
that the effective level thereof may be held at
any desired reduced point Within the .zone of
Preferably 'thermostatic ,controlling
means as 55 is Aprovided connected to the valve,
as by conduit 54, and arranged to open the valve 30
and so raise the water level upon a rise of super
heated steam temperature above a desired point,
and close the valve to depress the level upon a
fall of such temperature. Preferably a manually
operable bypass is arranged around the thermo 35
static valve, as at 59, so that when no steam
is flowing to control the thermostatic valve the
Water tubes may nevertheless be flooded, to pro
tect the dry steam tubes, by opening the hand
bypass. It will be obvious that the mechanical 40
arrangement of these and other lparts may be
varied in many ways. It will also be understood
that the generation of steam within the Water
tubes 30 in combination with the throttled inlet
makes possible »maintenance of a depressed level.
That is to say, while the presence of rising -steam
sembly being projected through îa bushing, as 40, bubbles ofl increasing size involves the presence
extending through and `flanged on 'either side of» of entrained water throughout ordinarily the full
one of the leg walls 2û--2l to seal it therein.
The bushings 40 and their l»securing ïaïnd sealing
flanges are preferably sufficiently heavy >to ma
terially strengthen and reinforce `the plates form
ing the jacket walls, thus not only compensating
for the weakening eifect of the apertures through
which the tube assemblies project, but serving as
reinforcing elements similar in action to 'stay
bolts. The assemblies may be slidable in the
bushings to provide for expansion and contrac
The ends of the tube assemblies project beyond
the leg walls and into transverse front and rear
header assemblies 42-44 and 42'--44' respec
tively. The steam header portions 42-42’ -are
shown as of rectangular section, as indicated in
65 Figure »3, and apertured along their facing Walls
to receive the open ends of the steam tubes 33
as well as the central water tube of each ele
ment. To the vcentral water tube 3D of each
element a projected extension 3l is 'attached
70 which extends across and through the opposite
wall of the steam header, in which it is'of course
sealed, and opens into a water header 44 or
44” shown las 'carried by vthe wall of 'the steam
header and formed of a half tube extending
75 along the-outsideV of the farther wall and over
height of each tube, so that the level may not
be ’a 'sharply defined one, and some heat absorb 50
ing power arising from the presence of Water
may exist all the Way to the top, there is never
the less a definite and controllable though grad
ual reduction of heat absorbing capacity from
the bottom to the top of the active portion of 55
the pipe, and such a throttling of the Water
inlet that gravity in effect maintains a reduced
level in the water tubes. The presence'of some
entrained water all the way to the top of the
tubes, however, is a valuable safety factor under 60
extremeV conditions, as it is sufficient to safe
guard 'the tube.
VIt will be understood that the throttle valve 152
actually constitutes an expansion valve, since
below it the pressure is greater than above by 65
reason of the head of water in the boiler, the
pressure in the steam tubes of the superheating
elements above the valve being less by reason of
the reduced quantity of liquid, and the free evap
oration of suchy liquid which there takes place. 70
By _reason of such free vaporization of the throt
tled quantity of water, only gravity tends to -hold
the 'water in the bottoms of the steam channels.
A sharply defined water level is thus avoided,
and the presence of some entrained iwater
throughout the steam tubes assured by the rising
bubbles of the rapidly boiling Water.
' Preferably a continuously rising gradient ob
tains throughout each water channel from its in
let until the discharge is reached; that is to say
that while a downward discharge may be used,
there are no return bends providing rising
gradients after a falling gradient, and all possi
bility of water traps and steam pockets is thus
10 eliminated.
Upon an inspection of Figure 4 it will be seen
that the welded areas 36 form the only integral
metallic connection between the water and steam
tubes 35i-33, and therefore the only heat bridge
15 through which any rapid heat transference can
take place. The heat-bridging welds 3% will be
seen to be arranged at the surface of the as
sembly in such fashion as to assist in the con
duction of heat to the steam within tubes 33 in
20 sections of the assembly containing virtually no
water in central tube 3D, while Where or when
water is present in the central tube, the tendency
of heat to flow to the coldest object and the rela
tive physical lengths of the heat paths between
254 the steam and the outside of the assembly on the
one hand, and the water and the outside of the
assembly on the other, renders the latter path
shorter than the former in terms of ease of heat
flow, so that heat is removed from the outside
30 of the assembly before it can reach the steam, and
the walls of the steam channels are prevented
from rising above a desired temperature. Be
cause of the absence of a direct integral radial
bridge between the water and steam channels,
35 however, water and saturated steam in the former
channel cannot desuperheat the steam in the lat
spiraled assembly of integrated steam tubes 33a
and a central Water channel portion which is in
this instance fabricated of a plurality of chan
neled plates 30a curved conformably to the tubes
33a and extended sufficiently far to project be 5
tween and space apart each two adjacent steam
tubes and provide exposed edges adapted to be
secured by the same welds 36m which secure the
The plates 30a, by Virtue of their Welded
integration with the surface of the assembly serve
to conduct heat directly from the outside to the
water where present on the one hand and on the
other hand to so greatly restrict as to virtually
prevent direct heat conduction between the steam
and water conduits by reason of the insulating
eñect of the schisms or planes of cleavage bc~
tween the plates and tubes. The operation and
characteristics of the assembly may be substan
tially the same as those of the form first de
scribed and shown cross sectionally in Figure 4.
The lire tubes of a lower bank, as lla, are
formed large enough to receive the forward ends
of the units, which are extended therethrough
and project into the smoke box 6B near the
bottom thereof. The section of each unit which 25
projects rearwardly into the fire box l5a from
the bulkhead 6| is disposed at such angle as to
properly Support the balliing arch 22a, and is y
looped around the rear edge of the arch and again
projected forwardly through the bulkhead 6|
near the top thereof. Each unit so projected
through the bulkhead may be sealed therein, as
by means of the sleeve 11, to which it is Welded,
while the looped U-sections preferably terminate
just inside the bulkhead, at which point each is
coupled to an extension as 'I8 serving to connect
ter by absorption directly through the walls.
it to headers 42h-Mb, the former constituting
The methods of calculation of rates of heat trans
ference and relative lengths of heat paths in pro
40 portion to relative temperatures, being well un
derstood in the art, they need not be set forth
tube discharge header. The headers 42h-44h
here, the important consideration being the pro
portioning of the fins 35 and positioning of the
may be assembled in a manner generally similar 40
to the headers ¿l2-44 previously described, and
of the superheater is only that above the effective
similarly connected to the component tubes of
the extensions 'i8 of the superheater units. The
header assembly is preferably located at a high
point, partly or entirely within the dome 25a, as
shown, and the inlet to the steam header may be
controllable by the throttle valve ‘I0 of the engine.
The tubes of the extension '18 need not be spi
raled since the considerations which motivate
the spiraling within the ñrebox (i e., equal ab~ 50
sorption of radiant heat) are here not present.
The discharge from the water tubes 3Q may be
water level, while the parts are so proportioned
that below such level substantial equilibrium is
ing from outlet header ¿4b and bent downwardly
welds 3E in such manner that despite the outer
45 disposition of the steam channels, the water takes
the excess heat from the outside Walls when and
Where present in substantial amounts, (and not
merely entrained with bubbles) thereby prevent
ing the heat from reaching the steam and guard
50 ing against over superheating in such areas.
Generally speaking, therefore, the active portion
55 maintained, so that steam passing downwardly
therethrough is not desuperheated, although it
cannot obtain more heat to be additionally super
heated. To preserve equilibrium and prevent de
superheating outside the zone of heat absorption,
60 the welded joints 35 are preferably terminated at
the boundary of the Zone of heating, as indicated
in Figure l at 35’.
In Figures 5, 6 and 7 a somewhat modiñed ar
rangement is shown in which no steam inlet or
65 Water tube outlet headers, or other connections,
need be arranged within the cab, and wherein sat
urated steam is delivered to the superheater di
rectly at the dome and within the boiler, while
the water tubes also terminate and discharge
70 within this portion of the boiler. In this con
struction the superheated steam discharge is at
the smoke box end of the boiler and close to the
steam chests„so that long delivery pipes are also
the steam inlet header and the latter the water
, The superheater umts are shown formed of a
through one or more outlet pipes as 38h emerg
to discharge above the water level in such man
ner as to both guard against the splashing or
surging of water into the water tubes and prevent
the discharge of saturated steam and entrained
water into the dome.
'I‘he forward extremity of each superheater (50
unit is connected to a header assembly comprising
steam outlet and water inlet headers ‘32a-«34a
respectively, shown as arranged within the smoke
box 60. The water header 44a through which
the water tubes 30a of the superheater units are
supplied with water from the boiler is directly
connected to the forward end of the boiler by
water inlet pipe 41a., while the ñow through the
latter and so the effective level in the Water tubes
is controllable by an inlet valve 52a, by which the
Water supply may be throttled. The operation of
this valve may be similarly controlled thermo~
statically in response to the temperature of super
heated steam, as by the thermostatic means di
agrammatically illustrated at 54a, while a hand
operated bypass may be provided for like rea
sons, as at 59a. From the header 42a the super
heated steam may be conducted directly to the
steam chests through steam pipes 15, shown as
extending within the smoke-box, though this is of
course entirelyoptional, and outside connections
might be used if desired.
In this construction also the steam is made to
flow downwardly through the units during super
heatíng, saturated steam being collected from the
drum directly at the throttle valve port in the
dome, Which serves as a take-off and is directly
connected to the inlet header 66, by which it is
shown as carried. The- only access to the super
heater tubes 33 is thus arranged Well above the
water level and within the steam dome in a posi
tion eüectively guarded against splashing.
The bridging welds 36a are preferably provided
only within the zone of radiant heat absorption,
Y20 and terminate substantially at the boundary of
such zone. This is particularly important at the
outlet end of the assembly to prevent desuper
heating of the steam. At the upper end of the
assembly the termination of such welds is of
25 course a matter of no consequence, since the
steam and water tubes are here at substantially
cluding ñre tubes connecting said ñrebox and
smoke box, said boiler also being provided with
a collecting dome for saturated steam Vlocated
above the Water level, a superheater assembly
comprising integrated steamV and Water conduit
portions looped through the ñrebox and termi
nating at their upper extremities appurtenant
the dome, said steam conduit portions having in
let means within the dome, the water conduit
portions having chscharge portions above the
water level, at least the steam conduit portions
oi said assembly extending through the ñre tube
portion of the boiler and having discharge por
tions` appurtenant the smoke box, and control
lable water inlet means for the lower ends of
the water conduit portions.
2. In a locomotive construction, in combination
with a fire tube boiler having a ñrebox at one
end and a smoke box at the other and including
iire tubes connecting said fire box and smoke box, 20>
said boiler also being provide-d with a dome lo
cated above the water level for collecting satu
rated steam, a superheater assembly comprising
integrated steam and water conduits terminating
at their upper extremities appurtenant the dome,
the steam conduit portion having an inlet with
the same temperature. At the lower end of the
assembly the line of termination of the bridging
in the dome.
welds is designated 36o.
The operation of this form of my invention
will be seen to be quite similar to that previously
described. The admission of water to the steam
ing a ñrebox portion and having a collecting
dome for saturated steam, a water regulated ra 30
channels is so controlled as to hold the water .at
reduced eifeotive level, vand to vary the `effective
superheating surface, while the design of 'the
tubes is such as to perform the interprotective
function previously discussed.
It will be understood that the lower ends of
the looped units might be projected through the
40 water leg 20a after the manner of the ñrst em
bodiment, if desired, and that the continuation
thereof through the lower flues I'la, while af
fording some additional heat absorption, is of
convenience particularly because affording de
livery of steam at a point close to the chests.
The ilues Ila, or if desired only the units Within
them, may be inclined upwardly somewhat to
insure the proper flow of steam generated in the
water tubes. If the superheater units are grouped
50 so closely in order to enable them to pass through
a lower portion of the generally cylindrical boiler
that they do not bridge the full Width of the fire
box, additional support for the arch 22a may be
furnished by simple water tubes as 23 arranged
therebeside and connected at their forward ends
to the boiler or front leg 20a and at their rear
ends to back leg `2 la.
Although I have shown and discussed a cross
' sectional arrangement of steam and water tubes
60 which I regard -as preferable, it will be under
stood that changes may be made without de
3. In combination with a firetu‘oe boiler hav
diant superheater assembly comprising inte
grated steam and Water conduits extending
through the fire box portion and to a position
appurtenant said dome, the steam conduit por
tions having an inlet Within the dome.
fi. In combination With a nre tube boiler hav
ing a ñrebox portion and having a collecting
dome for saturated steam located above the Water
level in the boiler, a water-regulated radiant su
perheater assembly comprising integrated steam
and water conduits extending through the ñre
box portion and to a position appurtenant said
dome, the steam conduit portions having an inlet
Within the dome and the water conduit portions
having an outlet also arranged above the water
5. In combination with a ñre tube boiler hav
ing va ñrebox portion and having Va collecting
dome for saturated steam located above the Water
level in ‘the boiler, a water-regulated radiant su
perheater assembly comprising steam andA water
conduits having metallically integral portions
extending through the ñrebox and being extend
ed from said ñrebox through the boiler portion
and at least a portion of said assemblybeing pro
jected into the dome, said steam conduit portions
having an inlet within the dome, and the Water
con-duit portions having an outlet also located
above the water level.
6. In combination with a ñre box and a fire
tube boiler including water containing portions
parture from the spirit of -the invention, which is defining Wall portions ofY the fire box, and ñreV
to be limited only by the scope of the subjoined tubes extending from said ñre box through one
claims. `Under extremely high ratings, for ex-v of the water containing portions, steam collect
ample, it might be advisable to» run the steam
ing means for said boiler arranged above the
through the inner tube and the »water throughV
water level therein, and a superheater compris
the outer tubes. Whether the steam iiows up or
ing a plurality of assemblies of water and steam
down the unit will be seen also to be a matter of
choice, as lis also the use of boiler Vwater rather tubes, said tubes of each assembly being arranged
than an external source of supply for the cooling for ready heat transference with one another, 710.
extending from said water-containing, and wall
portions and through said ñre box, the water
What I claim is:
tubes of said assemblies being regulably Ycon
1. In a locomotive construction, in combina
tion with a iire tube boiler having a i'lrebox at nected to a water-containing portion of the boiler
and the steam tubes Athereof extending through 754
one end and a smoke box at the »other and in
but being unconnected to the Water containing
portions and being connected to the steam co1
lecting means.
7. A superheater construction as set forth in
claim 6 in which said fire box has a bañiing arch
therein, and said Water and steam tube assem
blies support said arch.
8. A superheater construction as set forth in
claim 6 in which the water and steam tubes of
said assemblies are helically intercoiled and inte
grally connected, and in which said fire box has
a bafñíng arch supported by said assemblies.
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