Steam-boilers.
Year: 1890

page_text: Date of Application, 7th Oct., 1890-Accepted, 13th Dec,, 1890
COMPLETE SPECIFICATION.
Steam-boilers.
I, JOHN BAIRD, Mechanical Engineer, a Citizen of the United States, residing at
No. 324 Lexington Avenue in the City, County, and State of New York, U.S.A., do
hereby declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
My invention more especially relates to the boilers of stationary steam-engines,
and particularly to those of marine-engines, in which it is essentially necessary
to secure the highest attainable steam-generating capacity within the smallest
practicable compass, and with the lightest weight of material consistent with the
necessity of resisting strains, due not only to heat and steam-pressure, but to the
working of the vessel.
In the construction and operation of steam-boilers, economy of material and fuel
is secured by having a large part of the heating-surface exposed to the direct action
of the furnace-heat.
Cylindrical boiler-shells should be of small diameter to insure safety in using high-
pressure steam; the limited area of such small shells, however, permits the use of a
small number of fire-tubes, only, and the use of such tubes, of the diameter and length
generally used in steam-boilers, would leave the area for draft and the surface
exposed to heat each too small for the ordinary grate-surface.
It is the object of my invention to obviate these and other disadvantages in steam-
boilers; to insure strength to stand a high pressure of steam; a thorough circulation
of the water, and a superior and economical combustion of material, with less waste
of material and water, and occupying less space than has heretofore been required
for boilers of equal capacity.
These ends I attain by combining with the other parts of a steam-boiler, four
cylindrical shells, arranged as follows:-
First, a horizontal, lower shell containing fire-tubes, and placed directly over the
furnace.
Second, an upper shell, directly over the lower one, connected therewith by vertical
tubes, and, like the lower one, also provided with fire-tubes, some above and some
below the normal water-level, which is at, or slightly below the centre of the boiler,
thus leaving steam-room in its upper space.
Third, two intermediate, supplementary, cylindrical shells, also provided with fire-
tubes, and arranged on each side of, and between the upper and lower shells, the top
of these supplementary shells being about, or just below the normal water-level of the
upper shell.
The organization is such that the heat from the back connection returns through
the fire-tubes of both the lower and intermediate shells, and then passes back
through the upper shell to the smoke box before entering the back connection,
however, the heat acts externally on all the shells below the water line. The increased
fire-tube surface contained in these intermediate shells constitutes a valuable addition
to the heating surface; but the additional area for draft through those tubes is not
only a valuable addition but an essential addition to the area for draft, without which
the steam-generating capacity of the boiler would be very much restricted on account of
inadequate area for draft in proportion to the grate surface.
Feed-water pipes, around which the heat passes, after escaping from the supple-
mentary shells, are arranged above them, and on each side of the upper shell.
My improvements comprise further constructions and combinations of instrumen-
talities hereinafter specified.
My invention contemplates the use, in connection with my improved boiler, of the
most perfect apparatus of the present day. It is therefore unnecessary to describe in

page_text: detail the construction of the various parts; such details, unless otherwise specified,
being well known, and constituting no part of the subject-matter herein claimed, which
is specified at the end of this Specification.
In the accompanying drawings, which represent so much of a steam-boiler embodying
all my improvements, in one form, and that the best known to me-as is necessary to
illustrate the subject-matter hereinafter claimed.
Fig. 1 represents a front elevation of two of my improved boilers, side by side, with
the up-take or front casing removed from one of them;
Fig. 2, a vertical, longitudinal section therethrough on the line 2-2 of Figs. 1
and 4, looking to the left, with the up-take or casing in place;
Fig. 3, a similar section on the line 3-3 of the same figures, looking the same way;
Fig. 4, a vertical, transverse section, through both boilers, on the line 4-4 of
Figs. 2 and 3, looking backward;
Fig. 5, a vertical, longitudinal section through one of the feed-water heaters,
illustrating its details ;
Fig. 6, a vertical transverse section through the feed-water heater, looking forward,
and showing its tubes in section; and
Fig. 7, a similar view of its back head
:
Fig. 8, a vertical, transverse section, on the line 8-8 of Fig. 3, showing the details
of the arched-head water-space, connecting the back end of one of the supplementary
shells with the back head of the boiler;
Fig. 9, a vertical, longitudinal section through a supplementary shell, showing a
modification of this arched head, consisting of parallel tubes instead of a continuous
water-space;
Fig. 10, a vertical, transverse section, on the line 10-10 of Fig. 9, further illus-
trating this modification;
Fig. 11, a view in perspective of one of the sectional tubes of the lower shell,
showing its detachable connection;
Fig. 12, a vertical, transverse section through the bottom sheet of the lower shell,
showing the way in which the section fire-tubes are supported ;.
Fig. 13, a plan view of the upper sheet of the lower boiler-shell, illustrating its
connection with the upper shell;
Fig. 14, a sectional detail, illustrating the mode of connecting the brick-work with
the front and back heads; and
Figs. 15 and 16, similar details of the connection between the brick-work and other
parts of the boiler.
The figures illustrating details are, on an enlarged scale.
That end of the boiler in which the fuel, is inserted I call the front; the opposite
end, the rear or back. That side of the boiler. on the left of a person facing its, front,
I call the left; the opposite side, the right.
Tho short, unfeathered darts show tho, direction in which the sections are shown.
In Fig. 3, the solid, feathered, arrows show the course of the heat; the corro-
sponding, unfeathered arrows, that of the steam, and the dotted; arrows, that of
the water.
The drawings show a fire-box or furnace A, from which the.products of combustion
pass around, and through the various water and fire-tubes, by way of the back con-
nection A, front hood or up-take A2, smoke-box A³, and chimney, or smoke-stack A¹.
The brick-work of the boiler will be hereinafter described.
The front head C, and back head D, are each made of two parallel plates of metal,
properly stayed, with a water-space between them. The inside of the front head,
above the grate-bars, is fitted with fire-brick, and fastened as shown in. the detail
drawing-ig. 14-except that the tube-stays, fitted in the front head, are hollow.
Corresponding holes c, are made through the brick-work opposite them, thus admitting
air to the furnace above the fire, and simultaneously heating it by passing through
the hot brick-work. The lower part of the back-head D, is lined inside with fire-
brick D¹, like the front head. A stay D', passing through the back head, has a screw-
nut d, on its outer end; the inner end of the stay-bolt passes into a recess in the

page_text: brick-work, and is netd by a plate a', and nuta; the scary-boy
be hollow, as preferred.
Three series of water-tubes, E. E', E2, go from the back to the front head; they
may be either horizontal or inclined upwards from back to front. These tubes are
arranged alongside the side walls of the furnace; also under and alongside the
lower shell, and also in the space between the lower shell and side walls. They are
fastened to the inner plate of the front head, and holes fitted with plugs e, are made
in the outside plate opposite each tube, to allow for cleaning or taking out, or
putting in a tube.
These water-tubes pass through sleeves e', fitted water-tight in the back head,
and are supplied with water therefrom by small bent tubes e³. This construction
prevents any leakage from expansion or contraction of the water-tubes.
The water-tubes E2, which go under and alongside of the lower shell, usually lio so
close together that, when in place, entrance to the back connection would be prevented.
I obviate this difficulty by making one or more of these tubes in two fengths or
sections, e, e, Fig. 11, one section extending from the front head of the back con-
nection-see Fig. 2-the other screwing into it through a sleeve in the back head.
The rear end of the front section is supported by a bracket E³, fitted and fastened to
the lower shell F-see Fig. 12.
The water-tubes E, run along the sides of the furnace, close to, and parallel with
each other, but not contiguous. To prevent the exit of flame and hot gases between
these tubes, a fire-brick wall B, is built outside of them and backed on the outside
with plates b, the joints of which are covered by angle-iron bars, or plates b',
secured to the ends of the front head and back heal D, by bolts and nuts.
This construction, while not absolutely necessary in land engines, is very serviceable
on board ships exposed to rolling and pitching, as it prevents the diplacement of the
brick-work by the motion of the vessel.
•
The openings between the sides of the boiler, and between the upper shell and the
intermediate supplementary shells, are to be filled with fire-brick and lute, as shown,
or any suitable substance, so as to prevent the passage of the products of combustion
except through the proper channels.
By the construction of this boiler with fire-brick over and at the sides of the furnace,
I secure a higher temperature than usual in steam-boiler furnaces, thus insuring inore
perfect combustion, and more effective heating surface.
The lower shell F, rests on the front head, and extends rearward, to the front end
of the back connection; a suitable space A', being left between the back end of the
lower shell, and the back head, to form the back connection.
In order to insure an improved combustion by retaining the heat from the products
of combustion, I cover the bottom of the lower shell with fire-bricks F', which extend
around nearly one half of the shell, and retain them in place by water-tubes E³,
extending from the front to the back head. I fasten the fire-bricks to the shell in
a manner similar to that above described and shown in Fig. 16, to retain them properly
in place, and permit of the withdrawal of a tube, when necessary.
The lower shell is filled with fire-tubes, through which the products of combustion
pass.
The upper shell G, runs from the front end of the boiler over, close to, and parallel
with the lower shell, with which it is connected at frequent intervals by pipes -
Figs. 2 and 13-extends over the back connection, and rests upon the back head, thus
supporting the lower shell. The upper shell is likewise filled with fire-tubes g',
through which the products of combustion pass. This shell is normally about half full
of water; consequently its lower portion constitutes a water-space, and its upper
portion, a steam-space.
The lowest, g, of the fire-tubes of the upper shell, lies directly over the openings or
pipes g, connecting its water-space with that of the lower shell; consequently the
water and steam, rising through these openings, strike against and are deflected
laterally by this tube; as their ascent continues, they successively strike against the
upper tubes g', and separate the steam and water; the former being superheated in

page_text: the upper part of the boiler, thus supplying dry, superheated steam. A perforated
steam-pipe G, leads from the upper part of this shell to the steam-pipes supplying the
engine.
The intermediate, supplementary shells H, H', are arranged on opposite sides of,
parallel with, and in the spandrel recesses between the upper and lower shell; their
front ends being supported by the front head, and their fire-tubes h, running back to
the front end of the back connection. An arched hood H2, having a water-spaco
therein, connects the back ends of the fire-tubes with a downwardly-projecting end or
water-box, which rests upon the top of the back head, thus supporting the back end
of the intermediate, supplementary shells. A bent water-tube ¹, connects this water-
box and back head see Fig. 3.
Figs. 9 and 10 represent a modification in which the arched hood H2, is shown as
composed of a series of pipes h².
Both forms of these arched hoods are to be covered with fire-brick or pottery, as
shown in the drawing.
Small pipes, connect the tops of the back ends of the supplementary shells with
the upper shell G, thus allowing any steam generated in the former to escape into the
latter these pipes also serve for the passage of air in filling the boiler; as hereinafter
describe 1. Similar pipes y³, g, connect the upper parts of the front and back heads,
respectively, with the steam-room of the upper shell.
The sides of the boiler are run up to a level with the top of the upper shell, and the
space between them is covered over by plate-iron or other suitable material. The
space thus enclosed forms a channel on each side of the upper shell, into which
the products of combustion from the up-take are discharged; this channel runs across
the back end of the boiler, and discharges into the smoke-pipe there.
Feed-water heater-pipes i, are arranged in the channels alongside the upper shell,
and over the intermediate shells; these water-tubes are shown as arranged in two sets,
divided horizontally, and extending from the front end of the up-take to the back end
of the channel. A vertical tube-box 1, extends across each channel, being securely
fastened in place. The rear end of the feed-water heater-tubes i, i, are secured to
the front of this box, while their front ends are secured to two separate boxes I, I,
lying one above the other, the incoming tubes passing through one box, and the out-
going ones through the other; these boxes are so secured in place as to prevent any
movement vertically or laterally relatively to the pipes, but are so arranged as to move
backward or forward to compensate contraction or expansion of the pipes. These
pipes being placed in the smoke-channels, are heated by the products of combustion,
just before their escape into the smoke-pipe, thus economizing fuel, and heating the
feed-water.
The feed-water inlet is furnished with the usual check-valve M.
A safety-valve K, fitted on the upper side of each of the upper tube-boxes I', at the
front end of the side channels, has its discharge-pipes &,, connected with the steam-
space of the upper boiler-shell, a pipe 2, connecting it with the feed-box I'.
When
the boiler is being filled with water, these safety-valves are opened to allow the air to
escape. A blow-off pipe L, is fitted to the lower tube-box at the front end of the
boiier. When in operation, the feed can be shut off, and the blow-off and safety-
valve opened a current of steam will then flow through the water-tubes in the
channel, and clear them of sediment or scale.
The smoke-box is sometimes placed at the front end of the boiler, directly over the
up-take.
The up-take A, of the usual construction, is fitted to the front end of the boiler,
and the products of combustion from the fire-tubes of the lower and intermediate
shells are discharged into it.
In batteries of two or more boilers, the after-channel runs across their ends to a
common smoke-pipe. In some cases a duplicate set of boilers and batteries is placed
with their back ends facing each set, discharging into a common smoke-pipe.
When the boilers are arranged in battery, or side by side, one fire-brick wall B2,
between them and their side-pipes E-Fig. 4-answers for each pair of boilers and

page_text: holds the pipes securely against any tossing of the vessel. These partition walls I
prefer to make of sufficient thickness to enclose metal stanchions connecting the
decks above and below the boilers, the thickness of the brick-work protecting the
stanchions from injury from the heat of the furnace.
The following is a description of the operation of the boiler; the water in the
front and back heads, and in the tubes E. E', E, in the furnace, is heated by the
direct action of the flame. The side-tubes E. are further heated by heat absorbed by
and reflected from the side-walls B. The tubes E2, are similarly heated. The fire-
brick F, interposed between these tubes and the bottom of the lower shell become
highly heated and transmit their heat to the lower shell. The products of combustion,
after acting externally on all the shells, pass up through the back connection and
forward through the firo-tubes of the lower, upper, and intermediate shells to the up-
take in front; thence passing back around the feed-water heater-tubes, and the
outside of the upper shell, and finally escaping through the smoke-box at a much
lower temperature than ordinary.
The feed-water enters the lower front tube-hoxes I, through the tubes i, and passes
backward and forward in them, through the channel; thence passing through the rear
tube-boxes 12, into the upper tubes i, and through the front upper tube-boxes 1', and
pipes, to the water spaces of the intermediate shells; thence through the hood E,
head 3, and pipes to the back head. Small pipes e², connect the back head with
the water-tubes E, E1, E2, in the furnace, through which the water passes to the front
head, which is connected by suitable pipes f', with the lower shell; thence passing
through the connecting-pipes into the upper shell. All the steam generated passes
through its proper channels, as indicated by the arrows, into the steam space of the
upper shell.
It will be seen from the foregoing description that the lower shell is located
centrally in the fire-box, so as to be exposed on all sides to its heat; that the lower
portion of the upper shell, or that portion below the water-line, as well as the tubes
connecting the upper and lower shell, is likewise directly exposed to the heat and that
the intermediate shells are also enclosed in the brick-work of the fire-box, and:
similarly exposed externally to its heat; the advantage of which organization will
readily be understood.
Another advantage incidental to this improved organization is that the parts are
compactly arranged, occupying a comparatively small space, vertically, which is
especially advantageous in marine boilers.
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. The combination, substantially as hereinbefore set forth, of a furnace or fire-
box; a back connection; a front hood; a central lower shell; an upper shell parallel
therewith water-tubes directly connecting these shells, and an intermediate shell on
each side of the lower shell, below the water-line, all the shells being provided with
horizontal fire-tubes, and the organization being such that the products of combustion,
after impinging on the exterior of all the shells, return simultaneously to the front
hood through the tubes of the lower and intermediate shells, and then escape in the
reverse direction.
2. The combination, substantially as hereinbefore set forth, of a furnace or fire-box;.
a central lower shell therein; an upper shell; water-tubes directly connecting them ;
intermediate shells in the spandrel recesses, between and on opposite sides of the upper
and lower shells, below the water-line; and horizontal fire-tubes filling all the shells,
the organization being such that all the shells are enclosed within the casing of the
fire-box, and are exposed to the direct action of the products of combustion, which.
first act simultaneously upon the exterior of the shells, and then pass through the
fire-tubes.
3. The combination, substantially as hereinbefore set forth, of the furnace; the

page_text: lower shell therein; and the fire-brick directly secured to the outer surface of the
bottom of the shell.
4. The combination, substantially as hereinbefore set forth, of the furnace: the
lower shell therein; the water-tubes surrounding the shell; and the fire-brick
interposed between the tubes and shell, and secured directly to the latter.
5. The combination, substantially as hereinbefore set forth, of the furnace; the
lower shell therein; the upper shell; the intermediate shells; and the water-tubes
surrounding the lower shell.
6. The combination of the side walls of the furnace: its external plates and anglo
iron bars; and its internal, bracing water-tubes, the combination being and
operating substantially as hereinbefore set forth.
7. The combination, substantially as hereinbefore set forth, of the lower shell; the
upper shell; the intermediate shells the furnace-walls; their internal, bracing
water-tubes; and the water-tubes interposed between them and the lower shell.
8. The combination, substantially as hereinbefore set forth, of the lower shell; the
upper shell the intermediate shells; the fire-brick secured to the lower shell; the
furnace-walls; their bracing tubes; the tubes surrounding the bottom of the lower
shell; and the tubes intermediate between these tubes and the furnace-wall
tubes.
9. The combination, substantially as hereinbefore set forth, of a fire-box; a back
connection; a front hood; a rear smoke-box; a fire-box; a central lower shell
therein; an upper shell; water-tubes directly connecting these shells; intermediate
shells in the spandrel recesses between and on opposite sides of the upper and lower
shells below the water-line; and horizontal fire-tubes filling all the shells, the
organization being such that all the shells are enclosed within the casing of the
fire-box, and are exposed to the direct action of the products of combustion, which
first act simultaneously upon the exterior of all the shells, on their way to the back
connection, whence they return simultaneously to the front hood, through the tubes of
the lower and intermediate shells, and again pass backward to the smoke-box through
the tubes of the upper shell.
10. The combination, substantially as hereinbefore set forth, of the fire-box; its
back head; a back connection; a front hood; a smoke-box projecting beyond the
back head; a boiler-shell between the back connection and front hood; its fire-tubes
terminating at the front of the back connection; a hood extending over the back-
connection to the back head, and pipes connecting said hood and head, the organization
being such that the products of combustion act upon both sides of the hood in passing
from the back connection to the smoke-box.
11. The combination, substantially as hereinbefore set forth, of a fire-box; a back
connection; a front hood; a smoke-box projecting beyond the back connection; a
boiler-shell between the back connection and the front hood; its fire-tubes, and feed-
water heater-tubes in the smoke-channel, above the boiler-shell, and projecting beyond.
it at each end, into the front hood, and smoke-box, respectively.
12. The combination, substantially as hereinbefore set forth, of a lower shell; an
upper shell; intermediate shells on opposite sides thereof; and feed-water heater-tubes
above the intermediate shells, on each side of the upper shell.
13. The combination, substantially as hereinbefore set forth, of feed-water heater-
tubes; intermediate shells, a lower shell; an upper shell; and connecting-pipes
through which the water flows successively from the feed-water heater-tubes through
the intermediate shells, the lower shell, and the upper shell, the upper part of which
constitutes the steam-space.
14. The combination, substantially as hereinbefore set forth, of a furnace containing
water-tubes a lower shell, the lower part of which is surrounded thereby; an upper
shell connected with the lower shell; intermediate shells on opposite sides of the
upper and lower shells; and feed-water beater-tubes on opposite sides of the upper
shell, above the intermediate shells.
15. The combination, substantially as hereinbefore set forth, of the furnace; the

page_text: front and back heads; and the central water-tubes having a removable section in the
back connection, to permit access thereto.
16. The combination, substantially as hereinbefore set forth, of the lower shell;
the sectional water-tubes; and the brackets sustaining the rear end of the fixed
section.
17. The combination, substantially as hereinbefore set forth, of the heads of the
steam-boiler; their fire-brick lining; a stay-bolt passing through the head into a
recess in the brick-work; and a holding-plate and clamp-nut in said recess.
18. The combination, substantially as hereinbefore set forth, of a shell; its arched
hood crossing the back connection; its water-box; the back head on which it rests ;
and a pipe connecting them.
19. The combination, substantially as hereinbefore set forth, of a boiler-shell; a
water-box; tubes connecting the shell and water-box; and crossing the back
connection; a back head on which the water-box rests, and a pipe connecting them.
20. The combination, substantially as hereinbefore set forth, of a safety-valve; the
feed-water heater-tube box connected therewith; and the pipes connecting the safety-
valve with the steam-space of the boiler.
21. The combination, substantially as herein before set forth, of the lower shell; the
upper shell; the pipe connecting them; and the lower fire-tube of the upper shell
arranged directly over these pipes to act as a deflector.
Dated this 25th day of August 1890.
JOHN BAIRD.