Improvements in or relating to Steam-boilers.
Year: 1891

page_text: Date of Application, 1st Sept., 1891—Accepted, 3rd Oct., 1891
COMPLETE SPECIFICATION.
Improvements in or relating to 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 marine and stationary steam-boilers
having their flues horizontal, or but slightly inclined, enclosed in suitable shells,
and surrounded by water-tubes, both horizontal and upright, or slightly inclined.
The objects of my invention are to secure a compact, simple, safe, and efficient
boiler of high steam-generating capacity. In order to carry out my invention, I
employ a front-head and a back-head, constituting water-boxes or water-spaces, and
fill the interval between these heads with a series of contiguous, parallel, upright,
or slightly-inclined water-tubes, connected at their lower ends with longitudinal
pipes, connected with the feed-water apparatus. These upright pipes are connected.
at top with the boiler-shell. A main boiler-shell of cylindrical form rests on the
correspondingly-shaped front-head, and extends directly over the fire-box to the
front end of the back-connection, which is formed by the space left between
the shell and head.
In some cases I form the top and sides of the fire-box of a series of upright,
contiguous water-tubes, of a flattened, arched shape, connected at bottom with
longitudinal feed-water pipes, and at their centers with the bottom of the boiler-
shell.
The products of combustion pass from the fire-box, through the various fire and
water-tubes, by way of the back-connection, to the up-take, and through direct and
return flues in the boiler-shell, to the chimney. A steam-exit pipe occupies the
upper portion of the boiler. The rear end of the boiler-shell is supported by semi-
girders, fastened to it, and resting on the back-head. The fire-tube portion of
the boiler-shell is enclosed by a series of parallel, transverse water-tubes, curved
correspondingly with the contour of the boiler-shell, arranged close together, and
constituting what I term a series of belly-band tubes, which communicate with the
bottom of the boiler-shell by short, vertical pipes, and with the top of the shell by
suitable pipes.
I also sometimes employ small side-shells, extending longitudinally through the
fire-box, and of a length equal to that of the main-shell. These shells are fitted
both with fire and water-tubes. The front ends of these shells are supported by
the front-head, while their back ends rest upon pipes connected with the back-head.
These small shells may also be surrounded by longitudinal water-tubes connecting
the front and back heads.
The upright side-tubes or casing-tubes are extended across the back-connection,
and either connected directly with the upper portion of the boiler, or by
cross pipes extending across the back-connection so as to insure an effective water-
circulation.
I also sometimes employ concentric, water-circulating pipes projecting from the
back-head into, or across the back-connection to afford additional heating surface
and interpose between the pipes in the back-connection and the girders
supporting the boiler-shell fire-brick, which serve to absorb and retain the heat at
that point.
The feed-water, before entering the boiler, circulates through pipes in the back-
connection or up-take, by which it is highly heated. Fire-brick is interposed

page_text: between the fire-box tubes and belly-band tubes, and the boiler-shell, to prevent
the direct impingement of the products of combustion upon the shell.
Other features and details of the improvements will appear from the ensuing
description.
The first seven figures of the accompanying drawings represent one form of my
improved apparatus, in which-
Fig. 1 is a vertical cross-section, on the line 1-1 of Fig. 2, looking backward, the
section being through the body of the boiler;
Fig. 2 is an elevation of the right side of the boiler, without its casing or
jacketing;
Fig. 3, a vertical, longitudinal, central section, on the line 3-3 of Fig. 1, looking
to the left;
Fig. 4 is a similar section, showing two boilers placed end to end;
Fig. 5 is a horizontal cross-section, on the line 5-5 of Fig. 1, looking down-
ward, and
Fig. 6, a corresponding, sectional, detail view, showing a modification of the
organization represented in Fig. 5;
Fig. 7 is a vertical, longitudinal section through one of the side-shells, on the
line 77 of Fig. 1, looking to the left.
The fire-door end of the boiler I term the front; the opposite end, the rear.
That side on the right-hand of a person facing the fire-doors, I term the right; the
opposite side, the left. Short, unfeathered darts indicate the direction of view of
the corresponding sections; solid, feathered arrows, the course of the hot gases,
and dotted ones, that of the water. Unless otherwise indicated, the parts are of
nsual approved construction.
The products of combustion pass from the fire-box A, through and around the
various flues or fire-tubes and water-tubes by way of the back-connection A¹,
front-hood or up-take A2, direct-flues A³, and return-Hues A', in the upper part of
the boiler, and thence up the chimney.
A deflector a, projecting into the front-hood, between the direct and return-flues,
and a back-hood a', connecting these flues, serve to conduct a portion of the hot
gases through these flues, back to the chimney, up which another portion goes
direct from the front-hood.
The front-head C, and back-head D, are made of parallel plates, with water-
spaces between them, and are provided with the usual fire-doors and man-holes.
A large cylindrical shell E, with flat ends or heads, rests on the correspondingly-
shaped front-head, and extends directly over the fire-box to the front end of
the back-connection, which is formed by a space left between the boiler-shell and
back-head.
B shows a portion of the brick-work of the back-connection. About the lower
two-thirds of the shell is filled with fire-tubes e; the lower part of this shell com-
municates with the water-space of the back-head, by means of a series of pipes e'--five
or six in number-arranged horizontally across the back-connection. The rear end
of the shell is mainly supported by semi-girders E¹, fastened to it, and resting on
the back-head. The normal water-line of the boiler comes just below the level of
the direct-flues A³. A steam-pipe G, traverses the top of the shell longitudinally
between the return-flues A, and is thus dried and superheated.
The fire-tube portion of the boiler-shell is encompassed or enclosed by a series of
parallel water-tubes F, curved correspondingly with the contour of the boiler-
shell, arranged close together, and constituting what I term a series of belly-band
tubes, the central portions of which communicate with the bottom of the boiler-
shell by vertical openings or short pipes f, while their upper ends are connected
with the steam-space of the boiler by curved pipes.
The side-walls of the furnace are also composed of a series of parallel, upright,
or slightly-inclined water-tubes H, lying close together, and filling the space
between the front and back head. The space between the belly-band tubes F, and
the boiler-shell is filled with fire-brick or fire-clay B, thus protecting the boiler.

page_text: shell from the direct action of the flame. Fig. 6 shows every alternate tube F, as
omitted, and thicker brick-work or fire-clay interposed between them and the
shell. These tubes, it will be observed, do not extend back of the shell into the
back-connection.
The outer or casing-tubes H, are connected at bottom with their respective,
longitudinal water-supply pipes I, which are connected with the water-space of the
back-head, and extend through the front-head, with which however they are not
connected to the feed-water heating apparatus hereinafter described. The upper
ends of the tubes H, are connected with the boiler by small pipes h, which,
together with the belly-band connecting-pipes /, above mentioned, pass through
bracing-plates H', secured to the boiler-shell. The casing-pipes H, may be
connected with the water-supply pipes I, and with their own small pipes h, at top
and bottom, either or both, by expansion-joints or jam-nuts, and the belly-band
pipes are provided with similar jam-nuts. These pipes rest upon the water-
supply pipes I, at bottom, and are supported at their upper ends by the brick-
work B, and bracing-plates H', above-mentioned, which organization allows the
pipes to expand and contract without injury. Instead of employing a separate,
small, connecting pipe h, for each casing-tube, these pipes might be arranged in
gangs or groups, connected with a larger pipe 2, leading to the boiler, as shown in
Fig. 2, where those of the back-connection are represented as so connected. These
casing-tubes are to be covered with asbestos, or similar non-conducting material,
and outside plates of iron, and the whole boiler is to be suitably jacketed with
non-conducting material.
Small side-shells K, extend lengthwise of the fire-box, beneath and on each side
of the main shell, with which latter they correspond in length. They are fitted
with flues, to make a broader and more equable draft from the furnace and back-
connection to the front-head. The front ends of these shells extend through the
front-head, with which they are connected by small-pipes ¹. They are connected
with the back-head by a vertical pipe K', which supports the rear end of each
shell, and is connected with the back-head by a horizontal pipe 3, thus serving
hoth as a support and as a conduit. This pipe 3, is preferably arranged outside
the brick-work of the back-connection, being cooler for joints, &c.
These small shells K, are likewise supported by parallel, longitudinal, water
tubes J, connected with the front-head, and extending through packed sleeves
in the back-head, with the water-space of which they are connected by small
pipes j.
Similar water-tubes L, M, are shown as arranged between the casing-tubes and
main-shell, below the latter, and on a level with the lower supporting-tubes of the
small shells K.
The upper ends of the casing-tubes H, enclosing the back-connection, are shown
as connected by cross pipes 3, instead of being connected directly with the boiler,
thus securing a circulation through them. I also utilize these pipes to support
brick-work B, interposed between them and the semi-girders e', and bridging or
roofing over the back-connection, thus retaining the heat therein. I sometimes
support this brick-work upon a series of concentric circulating-pipes N, screwed
into the back-head.
Fig. 4 shows two boilers similar to that above described, arranged back to back,
and provided with a single back-head common to both boilers, with which both
sets of shells are connected as hereinbefore described, and both sides of which head
are exposed to heat from both back-connections; the advantages of such an
organization are obvious.
Water-boxes O, arranged on each side of the front of the fire-box, are connected
by horizontal water-circulating tubes 0. Feed-water flows through a pipe o,
provided with a check-valve, through the water-boxes and tubes, which traverse
the up-take, and are heated by the escaping gases. Pipes ², connect these feed-
water circulating-pipes with the longitudinal water-supply pipes 1.

page_text: Fig. 8 is a front elevation, with the hood-casing removed :
Fig. 9, an elevation of the right-hand side of the boiler, without jacketing;
Fig. 10, a vertical cross section, on the line 10-10 of Figs. 9 and 13, looking
backward;
Fig. 1, a vertical, central, longitudinal section, on the line 11-11 of Figs. 8
and 13, looking to the left;
Fig. 12, a vertical cross-section through the back-connection, on the line 12-12
of Figs. 9 and 13, looking forward;
Fig. 13, a plan view, with portions broken away or omitted, to show the parts
beneath;
Fig. 14 is a cross section through the upper portion of the back-connection,
similar to Fig. 12, showing a modification of the method of supporting its fire-brick
roof, and
Fig. 15 is a vertical, longitudinal section, similar to parts of Fig. 11, illustrating
the same modification.
The corresponding parts of these figures are lettered similarly to those above
described, and will be readily understood without recapitulation.
of
The brick-work B', forming the roof of the back-connection, instead of resting
on cross pipes connecting the casing-tubes, H, above described, is supported upon
pipes, connecting the boiler-shell and back-head-see Figs. 12 and 13. Figs. 14
and 15, however, not only show the casing-tubes H, as connected by cross-pipes h³,
supporting the brick-work, but also as connected directly with the steam-space
the boiler by pipes . In this modification I substitute for the belly-band pipes
encompassing the boiler, a series of flat-arched, transverse water-tubes F, placed
close together, and forming the top and sides of the fire-box, their lower ends being
united to longitudinal water-supply tubes I, connecting the front and back heads,
and with which the casing-tubes H, are also connected. Expansion-joints or jam-
nuts F, similar to those herein before described, connect the tubes F, I. The
tubes F, are connected with the bottom of the boiler-shell by short, vertical
tubes The space between these arched tubes F, the casing-tubes H, and the
main shell E, is filled with brick-work or fire clay B, which also encloses the small
side-shells K, thus protecting all the boiler-shells from the direct action of the
flame.
The entire boiler, including its casing tubes, is to be jacketed or protected
wherever desirable to prevent loss of heat by radiation, and is also to be provided
with the most approved appurtenances, such as safety-valves, water-valves, cocks, &c.,
for filling, emptying, or regulating the flow of air, steam or water through the boiler.
The main shell, it will be observed, is in the form of a comparatively short, flat-
ended cylinder, of large diameter relatively to its length, while the whole structure,
including the casing, is substantially rectangular in cross section, thus leaving little
waste room.
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 boiler-shell, and
a series of water-tubes encircling its lower portion, the upper ends of the tubes
being connected with the steam-space of the boiler-shell, and their central portions
with its water-space.
2. The combination, substantially as hereinbefore set forth, of a boiler-shell; a
series of encompassing water-tubes connected with it, and fire-brick or fire-clay
interposed between the tubes and shell.
3. The combination, substantially as hereinbefore set forth, of a front-head; a
back-head; a boiler-shell; pipes connecting the back-head and boiler-shell, and a
series of encompassing water-tubes connected with the shell.

page_text: 4. The combination, substantially as hereinbefore set forth, of two boiler-shells
placed end to end; a back-head common to both shells; pipes connecting both
shells with the back-head, and a series of water-tubes encompassing the shells, and
connected therewith.
5. The combination, substantially as hereinbefore set forth, of a boiler-shell;
the fire-tubes traversing its water-space; direct and return flues traversing its
steam-space; a series of water-tubes encircling the lower part of the shell, and
connected both with its steam and water-space; a fire-box under the boiler and
tubes a back-connection, and an up-take connected with the direct and return
flues.
6. The combination, substantially as hereinbefore set forth, of a boiler-shell; a
scries of encompassing water-tubes connected with it, and a series of parallel,
substantially vertical water-tubes also enclosing the boiler and connected
therewith.
7. The combination, substantially as hereinbefore set forth, of a boiler-shell; a
series of water-tubes encircling its lower portion; water-passages connecting
them with the water-space of the boiler pipes connecting them with the steam-
space of the boiler, and bracing-plates and jam-nuts also connecting these pipes
and the boiler-shell.
8. The combination, substantially as hereinbefore set forth, of a boiler-shell; its
back-head back-connection; semi-girders connecting the shell and back-head, and
brick-work intermediate of the back-connection and these girders, to confine the
heat therein.
9. The combination, substantially as hereinbefore set forth, of a boiler-shell; its
back-head a back-connection; seini-girders connecting the shell and back-head;
a series of water-tubes projecting from the back-head into the back-connection, and
fire-brick interposed between the water-tubes and the semi-girders.
10. The combination, substantially as hereinbefore set forth, of a boiler-shell;
a front-head; a back-head; horizontal, longitudinal water-pipes connecting the
bottons of these heads; a series of upright side-tubes, connected at the bottom
with these tubes, and at the top with the steam-space of the boiler; bracing-plates
through which they pass, and jam-nuts securing the side-pipes in position.
11. The combination, substantially as herein before set forth, of a boiler-shell;
its encompassing tubes connected both with its steam and water-space; fire-brick
intermediate between the shells and these tubes, and a series of upright tubes
constituting the side-walls of the furnace.
12. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head; a boiler-shell; tubes encompassing the under side thereof, and
connected both with the water and steam space of the shell; horizontal, longitudinal
shells connecting the heads, and upright side-tubes connected with these tubes at
bottom, and with the steam-space of the boiler at the top.
13. The combination, substantially as hereinbefore set forth, of a boiler-shell;
its back-head; a back-connection upright water-tubes enclosing the back-
connection, and transverse pipes crossing the upper part of the back-connection,
and connecting these enclosing water-tubes.
14. The combination, substantially as hereinhefore set forth, of a boiler-shell;
its back-head a back-connection; semi-girders connecting the shell and back-
head; water-tubes projecting from this head into this connection; upright side-
tubes enclosing the back-connection; cross-pipes connecting their upper ends, and
fire-brick interposed between the semi-girders and sustaining pipes.
15. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head; a boiler-shell connected therewith; water-tubes encompassing the
lower part of the boiler-shell, and connected both with the steam and water-space.
thereof; longitudinal water-pipes connecting the bottoms of the front and back-
heads upright side-pipes connecting these tubes with the boiler; water-boxes
connected with these longitudinal bottom pipes, and feed-water circulating-pipes,
connecting these boxes across the up-take, to heat the feed-water.

page_text: 16. The combination, substantially as hereinbefore set forth, of a front-head:
a back-head; a boiler-shell (K) connected directly with one head at one end, and
supported at the other by a pipe constituting its connection with the other head.
17. The combination, substantially as hereinbefore set forth, of a boiler-shell (K);
a front-head; a back-head; a back-connection; an upright pipe (K¹) supporting
the back of the shell, and a connecting-pipe (3) crossing the back-connection.
18. The combination, substantially as hereinbefore set forth, of the boiler-shell (K);
a front-head a back-head; a back-connection; an upright pipe connected with
the back-head and sustaining the back of the shell, and longitudinal water-pipes (1)
encompassing the boiler-shell, connected with the front-head, and passing through
the back-head across the back-connection.
19. The combination, substantially as hereinbefore set forth, of a fire-box;
a front-head; a back-head; a main shell connected with them; water-tubes
encompassing the main shell and connected therewith; longitudinal tubes con-
necting the bottoms of the front and back heads; upright side-tubes connected
with these longitudinal tubes at bottom, and with the main shell at the top; small
shells interposed between the encompassing tubes and side-tubes; longitudinal
water-pipes supporting them, and vertical supporting-pipes constituting the con-
nection between the small shells and back-head.
20. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head; a main-shell; its connected encompassing-pipes; longitudinal water-
tubes connecting the front and back-heads; upright side-tubes connecting these
longitudinal tubes with the boiler-shell side-shells interposed between the boiler-
encompassing tubes and upright side-tubes; vertical water-pipes sustaining the
rear ends of these shells, and longitudinal water-tubes connecting the front and
back heads.
21. The combination, substantially as hereinbefore set forth, of a fire-box;
front-head; back-head; a main-shell connected therewith; its encompassing water-
tubes; longitudinal water-tubes connecting the heads near their bottoms; upright
side-tubes connecting these longitudinal tubes with the main boiler-shell; small
shells interposed between the main shell and side-tubes, and longitudinal water-
tubes connecting the front and back-heads.
22. The combination, substantially as hercinbefore set forth, of two boiler-shells
placed end to end; a back-head common to both; semi-girders extending across
the back-head and supporting both shells, and a steam-pipe, also common to both
shells.
23. The combination, substantially as hereinbefore set forth, of two boiler-shells
placed end to end; a back-head common to both shells; semi-girders connecting
them, and fire-brick constituting the roof of the back-connection of each shell.
24. The combination, substantially as hereinbefore set forth, of a boiler-shell;
a series of transverse arched tubes connected with its water-space, and forming the
top and sides of a fire-box, and fire-clay interposed between the tubes and
shell.
25. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head; a boiler-shell; longitudinal side-tubes connecting the front and back
heads, and a series of transverse arched water-tubes connecting the side-tubes and
main-shell, and constituting the top and sides of the fire-box.
26. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head longitudinal side-tubes connected to the front and back heads;
transverse arched water-tubes connecting these side-tubes, and constituting the top
and sides of the fire-box; a boiler-shell; fire-tubes traversing its water-space:
direct and return flues traversing its steam-space; a back-connection, and an
up-take connected with the direct and return flues.
27. The combination, substantially as hereinbefore set forth, of a front-head; a
back-head; longitudinal side-tubes connecting them; transverse arched water-tubes
connecting these side-tubes, and constituting the top and sides of a fire-box;
a boiler-shell connected with these tubes; its fire-tubes; its back-connection, and

page_text: upright casing-tubes enclosing this back-connection, and connected at their lower
ends with the longitudinal side-tubes, and at their upper ends with the steam-space
of the boiler.
28. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head longitudinal side-tubes connecting them; transverse arched water-
tubes connecting these side-tubes, and constituting the top and sides of a fire-box;
a boiler-shell connected with these tubes: its back-connection, and two series of
longitudinal water-tubes crossing the upper and lower parts of the back-connection,
and connecting the shell and back-head.
29. The combination, substantially as hereinbefore set forth, of a boiler-shell;
a series of transverse arched tubes connected with its water-space, and forming the
top and sides of the fire-box, and side-shells interposed between these tubes and
the main-shell, and fire-clay intermediate of said tubes and main-shell, and enclosing
the side-shells.
30. The combination, substantially as hereinbefore set forth, of a front-head:
a back-head; longitudinal side-tubes connecting them: transverse arched water-
tubes connecting these side-tubes, and constituting the top and sides of the fire-
box; a boiler-shell connected with these tubes; its back-connection; upright
casing-tubes enclosing it, and side-shells interposed between the arched tubes and
main-shell, and connected with the front and back heads.
31. The combination, substantially as hereinbefore set forth, of a front-head;
a back-head; longitudinal side-tubes connecting them; transverse arched tubes
connecting these side-tubes, and constituting the top and sides of the fire-box;
a boiler-shell connected with these tubes its back-connection; upright casing-
tubes enclosing it, connected at their lower ends with the longitudinal side-tubes,
and at their upper ends with the steam-space of the main-shell; a front-hood:
water-boxes connected with the longitudinal side-pipes, and feed-water circulating-
tubes connecting these boxes across the up-take.
32. The combination, substantially as hereinbefore set forth, of a main-shell; its
fire-tubes below the water-line; a direct and return flue in the steam-space of the
boiler-shell; an up-take; a deflector which causes a portion of the hot gases to
traverse these flues, and a steam-pipe extending between these flues, through the
steam-space of the boiler, and through the up-take to dry and super-heat the
steam.
33. In combination with a steam-boiler, the arrangement of water-pipes, as
described with reference to Figs. 1 to 7, both inclusive.
34. The modified arrangement of water-pipes, with reference to Figs. 8 to 15,
both inclusive.
Dated this 15th day of Lulu. 1901
JOHN BAIRD.