Improvements in Steam Boilers.
Year: 1892

page_text: Date of Application, 8th N.v., 1892-Accepted, 17th Dec., 189.
COMPLETE SPECIFICATION.
Improvements in Steam Boilers.
I, GEORGE FORREST TINKHAM of 16 Tyler Street in the County of Boston,
Massachusetts United States of America Mechanical Engineer do hereby declare
the nature of my said invention and in what manner the same is to be performed to
be particularly described and ascertained in and by the following statement :--
This invention relates to that class of steam boilers having one or more
substantially large flues through which the products of combustion pass and which
are surrounded by the water to be converted into steam. My present invention has
for its object to provide boilers of the class referred to, with apparatus by which
superheated steam and heated air may be commingled with the products of com-
bustion to enrich the same and to effect the complete combustion of the unconsumed
carbon and gases, thereby effecting an increased evaporating efficiency for the boiler
with a minimum expenditure of fuel, usually soft or bituminous coal.
In accordance with my present invention, a bridge-wall of fire-brick or other
suitable material located in the flue referred to, has in it a steam superheating
apparatus preferably made as a double coil of pipes, which are connected to the
steam-space of the boiler and with a steam-spraying or atomizing device by which
the steam, superheated in its passage through the coils, is injected into the fire-box
in finely divided streams or sprays, the said superheated steam being mixed with
heated air. The apparatus by which the superheated steam and air are supplied
to the flue of the boiler may be of substantially the construction shown and
described in my Patent No. 14365 of Oct. 6, 1888. The flue, at its front end, is
provided with an arch sustaining frame or casting preferably of cast-iron which
rests upon a substantially wide dead-plate and is surrounded on its top and sides by
fire-brick or other suitable refractory material. The fire-brick above the arch has
embedded in it the steam-atomizing or spraying device referred to, the said fire-
brick protecting the said device from being burnt out, and the brick-work which
surrounds the casting referred to, also protects the front of the boiler and enables
the said front to be made of substantially cheap material such as cast-iron, whereas
with boilers of this class as heretofore constructed, a substantially costly material,
such as wrought iron, was required on account of the high heat to which it was
subjected or exposed.
The boiler front is provided with a door of special construction, as will be
described, to form an air space.or chamber, into which the air is admitted through
a suitable opening in the front plate of the door, the air admitted into the said
chamber passing toward the top and sides of the arch-sustaining casting, and also
toward the dead-plate, thereby causing the air to be more effectually heated and
assisting to protect the casting from the heat, the air taking heat from the said
casting.
Figure 1, is a front elevation of a boiler embodying my invention.
Figure 2, a longitudinal section of the front portion of the boiler shown in
Figure 1, the section being taken on the irregular line 2-2 looking toward the
right, the steam-pipe being shown in dotted lines for a portion of its length.
Figure 3, a detail partially in plan and section of the atomizing or spraying
apparatus, and the boiler front plate."
Figure 4, a detail in elevation of the steam-superheating coil to be referred to.
Figure 5, a detail in perspective of the arch-sustaining frame located in the flue
at the front of the boiler, and
Figure 6, a detail in plan view of one form of atomizing nozzle.
The boiler A, provided, as herein shown, with two substantially large flues A'

page_text: may be of any usual or well-known construction common to this class or type of
boilers.
Each flue A has located in it, a bridge-wall A2 forming with the front of the
boiler a fire-box or combustion chamber A³, in which is located the fire-grate con-
sisting, as herein shown, of two sets of grate bars a a', the set a being supported
at one end by an offset or ledge a² on a dead-plate a³ resting on a portion of the
bridge-wall, the other end of the grate bars a being supported by an inverted
T-shaped bar a', which also supports one end of the set a¹ of grate bars, the other
end of the said bars resting on an offset or ledge a' on a dead-plate a³.
The dead-plate a, in accordance with my invention, is made substantially, wide
as represented in Figure 2, and supports an arch-sustaining frame or casting a',
shown separately in Figure 5. The casting a is made of less width than the
diameter of the flue A', and the space between the said casting and the walls of
the flue A is fitted in with refractory material a", such as fire-brick. The refractory
material a³ has embedded in it, preferably above the crown of the arch-sustaining
casting a', a steam and air atomizing apparatus, which may be of substantially the
same construction as shown and described in my Patent above referred to, but
which is herein shown (see Figure 3) as consisting of two air-conducting pipes 61
joined to a pipe 2, connected by a T-shaped pipe 63 to an air box 6 located outside
the boiler front , the air-box being secured to the pipe 63 by set screw 6º
substantially as shown in the Patent referred to.
The pipes are preferably provided with flaring or bell-shaped mouths and
have located within them steam-nozzles 67 68, which may be of the same con-
struction as shown in the Patent referred to, each nozzle having an enlarged portion
or shell 10 (see Figure 6) integral with a projection or nose-piece 612, the shell 6,10
having radial openings or ports 613 and surface grooves or channels 614 extended
toward the projecting piece 12, the latter being preferably provided with a central
hole, not herein shown. The nozzles 67 68 are connected to steam-pipes 615 616 joined
to a pipe which, as shown in Figure 1, by dotted lines, passes down through the
brick-work on the side of the arch-sustaining casting and through the dead-plate,
and is connected to the steam-outlet pipe 618 of the superheating apparatus embedded
within the bridge-wall A².
The superheating apparatus preferred by me is made substantially as shown in
Figure 4, and consists of two stand-pipes or risers cc joined by a double coil, that
is, two independent sets of coils, consisting as herein shown of pipes c² 3 c; c c c².
The stand-pipes c constitute the inlet stand-pipe and is connected by a pipe c8
extended through the bridge-wall and under the grate-bars to the outside of the
boiler, where it is joined to a pipe clo connected to a pipe c¹ having both ends, as
shown in Figure 1, communicating with the steam-space S of the boiler.
Each flue A¹ is partially closed by the front plate 6, having a door d provided
with an air register d¹. The door d, in accordance with my invention, has secured
to its inner side, as by stud bolts d³, an air deflecting plate d which forms with the
door d, a chamber or passage d³ into which air is admitted through the register d
and is heated therein, and passes from the top and sides of the said chamber into
the combustion chamber or fire box A3. The air is heated in the chamber (5 and
is also heated on its passage by the sides and top of the arch-sustaining casting a",
and is thus highly heated before coming in contact with the burning fuel, thereby
promoting combustion. By means of the deflecting-plate d, the air is retarded on
its passage to the combustion chamber and serves to protect the front. plate and
also the arch sustaining casting from burning out, by detracting some of the heat
from the said parts.
In operation, steam from the boiler is caused to circulate through the super-
heating apparatus embedded in the bridge-wall, by opening the cork or valve e in
the pipe c, and as represented in Figure 4, the steam enters the stand-pipe cat or
near its lower end, which is at or near the lower part of the bridge-wall, and the
said steam circulates through the double set of coils and passes out from the top of
the stand pipe c into the pipe 8, by which and the pipes 61, 61, 61, it is conducted

page_text: to the nozzles 7 18, and is by them thoroughly diffused or sprayed into the
combustion chamber. The steam issuing from the nozzles draws with it through
the air pipes bb, highly heated air, which is mixed with the finely divided steam
aud both are commingled with the products of combustion arising from the burning
fuel on the grate-bars, thereby enriching the said products of combustion and
uniting with the uncombined carbon and gases. The carbon is thus consumed and
the evaporating efficiency of the boiler greatly increased with a minimum amount
of fuel, which is usually soft coal.
same,
I have herein shown each flue provided with two nozzles and while I prefer the
I do not desire to limit my invention in this respect, as any desired! number
of nozzles may be used:. So also, I do not desire to limit myself to the particular
construction of nozzle shown, as other forms may be used.
Having now particularly described and ascertained the nature of my said inven-
tion and in what, manner the same is to be, performed I declare, that what I
claim is :-
1. In a boiler provided with a substantially large flue and having a bridge-wall
located therein to form a fire-box or combustion chamber, a superheating apparatus.
located in the bridge-wall, a steam-inlet pipe for said superheating apparatus
connected to the steam space of the boiler, a steam-spraying or atomizing
apparatus located within the flue and connected to the steam-outlet pipe for the
superheating apparatus, and an air passage co-operating with the steam-spraying
apparatus, substantially as and for the purpose specified.
2. In a boiler provided with a substantially large flue and having a bridge-wall
located therein to form a fire-box or combustion-chamber, a superheating apparatus
located in the bridge-wall, a steam-inlet pipe for said superheating apparatus
connected to the steam space of the boiler, an arch-sustaining frame or casting
located within the flue at its front end, refractory material interposed between said
frame or casting and the flue, an air passage in said refractory material communi-
cating with the atmosphere and with the interior of the flue, a steam-spraying
device or apparatus located in said air passage and connected with the steam outlet
for the superheating apparatus in the bridge-wall, substantially as and for the
purpose specified.
3. In a boiler provided with a substantially large flue having a fire-box within it,
an arch-sustaining frame or casting located within the flue at its front end,
refractory material enclosing the said frame on its top and sides, an air passage or
pipe in said refractory material communicating with the atmosphere and with the
said fire-box, a steam-spraying or atomizing apparatus located within the said air
passage, and a superheating apparatus located within the flue and connected with
the steam-spraying apparatus, substantially as and for the purpose specified.
4. In a boiler provided with a substantially large flue having a fire-box within
it, an arch-sustaining frame or casting, refractory material interposed between the
said frame and the flue, a door for said flue, and an air deflector secured to the said
door on its inner side to form an air chamber, substantially as and for the purpose
specified.
5. In a boiler provided with a substantially large flue having a fire-box within
it, a bridge-wall at the rear of said fire-box, a dead-plate at the front end of the
flue, an arch-sustaining frame or casting on said dead-plate, refractory material
interposed between the said frame or casting and the flue, air passages or pipes bb
embedded in said refractory material and communicating with the outside of the
furnace, steam-spraying or atomizing nozzles 67 68 in said pipes, a superheating
apparatus consisting of a double set of coils embedded in the said bridge-wall, a
steam-inlet pipe connected with the steam space of the boiler and with the said
coils, a steam-outlet pipe for the steam coils connected with the nozzles 67 68,
substantially as and for the purpose specified.
6. In a boiler provided with a substantially large flue having a fire box within
it, a bridge-wall at the rear of said fire-box, a dead-plate at the front end of the

page_text: flue, an arch-sustaining frame or casting on said dead-plate, refractory material
interposed between the said frame or casting and the flue, air passages or pipes
embedded in said refractory material and communicating with the outside of the
furnace, steam-spraying or atomizing nozzles 67 68 in said pipes, a superheating
apparatus consisting of a double set of coils embedded in the said bridge-wall, a
steam-inlet pipe connected with the steam-space of the boiler and with the said
coils, a steam-outlet pipe for the steam coils connected with the nozzles 67 68, a door
for said flue and an air-deflecting plate secured to the door. on its inner side,
substantially as and for the purpose specified.
· Dated this 30th day of November 1892.
GEORGE BARKER,
77, Colmore Row, Birmingham, Agent.