Improvements in Steam Boilers.
Year: 1893

page_text: Date of Application, 17th Jan., 1893-Accepted, 18th Feb., 1893
COMPLETE SPECIFICATION.
Improvements in Steam Boilers.
I, HENRY ALEXANDER LAUGHLIN, Manufacturer, residing at Ellsworth
Avenue and Bidwell Street, in the City of Pittsburg, County of Allegheny,
State of Pennsylvania, and United States of America, 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 :-
" tubulous or
The object of my invention is to provide a
"water tube" steam
boiler, of simple, strong, and comparatively inexpensive construction, in which a
large amount of grate area and direct heating surface may be afforded within small
compass, without involving the employment of the large number of joints and
connecting elements ordinarily used in boilers of this type, as well as to render all
portions of the structure readily and conveniently accessible for purposes of cleaning,
repair or renewal, to ensure a free, rapid, and continuous circulation of water, and
to afford ample facilities for the delivery of dry steam.
To this end, my invention, generally stated, consists in the combination of two
end casings or legs, inclined water tubes connecting said end casings, and a dia-
phragm or circulating plate located in one of said end casings above the lower
ends of the water tubes; also in certain other novel combinations hereinafter
fully set forth.
In the accompanying drawings:
Figure 1 is a vertical longitudinal section, at the line a, a, of Fig. 2, through a
steam boiler illustrating a form of embodiment of my invention;
Fig. 2, a front view of the same;
Fig. 3, a rear view, partly in section at the line of Fig. 1;
Y, Y,
Fig. 4, a vertical longitudinal section, at the line, of Fig. 6, through a steam
boiler illustrating another form of embodiment of my invention;
Figs. 5 and 6, vertical transverse sections, at the lines y¹y', and ' ', respectively,
of Fig. 4, and
Fig. 7, a plan or top view, the cap of the feed water casing being removed, in the
left hand half of the figure, and the steam and water receptacles, and entire feed
water heater casing, being removed, in the right hand half of the figure.
In the practice of my invention, as illustrated in Figs. 1, 2, and 3, I provide a
front and a rear end casing or leg, 1, 2, each of which is of substantially rectangular
form, and is constructed similarly to the water legs of ordinary tubular boilers,
that is to say, formed of sheets set at a proper distance apart to provide an inter-
mediate water space, and connected and braced, as against internal pressure, by
socket bolts, or by screw stays 3, as shown, the casings being closed at bottom by
mud rings, or, as shown, by channel plates 4, and being closed at top, (except
where they communicate with a steam drum or drums, as presently to be described)
by similar plates 5, and being also closed at their sides. The casings 1 and 2 are
Bet at such distance apart as to afford space between them for a fire and combustion
chamber of the length desired, and may, if desired, be connected by longitudinal
tie rods. A fire grate 7, which, in this instance, is composed of grate bars of the
ordinary form, extending longitudinally from one casing to the other, but which
may, if desired, be a water grate, is supported on bearers 8, above the lower ends
of the casings, which extend downwardly for a sufficient distance to provide a space
removed from the direct action of the fire, for the deposition of separated impurities,
which may be discharged, as from time to time required, by suitable blow off
cocks 9.
The space between the end casings is closed, at its sides, by walls which may, in

page_text: stationary boilers, be of brick, or, in the case of marine or portable boilers, be
formed of light sheet metal, lined with fire brick or tile, and cased with wood or
any suitable and preferred non-conducting covering. The fire and combustion
chamber, formed by the space between the casings above the grate 7, is closed at
top by a cap plate 10, provided with an exit flue or stack 11, and access to the fire
chamber is had through one or more openings 12 in the front casing, located above
the grate and provided with the usual fire doors 13. An ash pan 14 is located
below the grate, and ash pan doors 14º, at the front thereof, are provided for the
regulation of draught and the removal of ashes.
The end casings 1 and 2 are connected, at lower and higher levels respectively,
by inclined water tubes 15, which are secured, at their opposite ends, to, as by
being expanded into, the inner sheets of the respective sections, and which thereby
establish communication between the water spaces of the two casings. The water
tubes 15 are preferably arranged in vertical rows of two or any desired greater
number, three being shown in each vertical row in Figs. 1 and 3, and with an
alternately opposite inclination of the respective vertical rows. It will be obvious
that the number of tubes or of vertical rows, and the number of tubes in a vertical
row, may be varied in the discretion of the constructor, in accordance with the
proportions of width and height of the boiler which may be adopted in different
cases. Removable plates 16 are inserted in and secured to the outer sheets of the
casings 1, 2, opposite the ends of the tubes 15, said plates closing openings in the
sheets for the insertion of the tubes, and of an expanding tool for securing
the tubes in position in the sheets, as also for admitting access to the tubes when
desired for cleaning or removal. In order to enable the tubes 15 to be securely
expanded in the inner sheets of the casings, as well as to promote circulation, as
hereinafter described, the inner sheets may be bent outwardly and inwardly opposite
the lower and upper ends, respectively, of the tubes as shown in Fig. 1, so that
their surfaces will be perpendicular, or approximately so, to the tubes, at each end
thereof.
In order to provide proper and ample steam liberating surface and steam chamber
volume, the casings 1 and 2 are, near their upper ends, connected to and communi-
cate with a steam drum or drums, in which the normal water level is maintained.
In the instance shown in Figs. 1, 2, and 3, a series of cylindrical drums 20 is
employed, thereby affording a material increase of liberating surface, as compared
with a single one, without involving the weakness due to the necessarily larger
diameter of the latter. The drums 20 extend across the combustion chamber,
which encloses their lower portions between the end casings, and the drons may
be rivetted to flanges turned on the inuer and outer sheets of the casings 1 and 2,
or be connected thereto by angle irons. The steam supply pipe 22, leading to the
engine, is provided with the usual stop valve 23, and is, in this instance, shown as
connected to a supplemental steam drum 20%, which extends transversely to the
drums 20, and is connected thereto by short pipes 24.
A diaphragm or circulating plate 25 is fitted between the inner and outer sheets
of each of the end casings 1 and 2, a short distance above the lower ends of the
upper rows of water tubes 15, said plates being preferably, as shown, located between
the inwardly and outwardly bent portions of the inner sheets of the casings, and
therefore at or near the narrowest portions of the water spaces. The circulating
plates extend horizontally across the casings from points between the outer rows of
tubes and the adjacent ends of the casings, and are then downwardly prolonged, at
one or both ends, to a level adjacent to, and preferably below, that of the grate, a
vertical passage or passages, one of which is seen on the right of Fig. 3, being thus
provided between the downwardly extending portion or portions of each circulating
plate and the adjacent end or ends of the casing. As shown in Figs. 2 and 3, the
circulating plates 25 are downwardly extended at both ends, but if so extended at
one end only, their horizontal portions should extend to the opposite ends of the
casings. The circulating plates may be connected to the inner and outer sheets in
any suitable manner, and may be provided with a series of sockets 27, through

page_text: which pass a line of screw stays 3, connecting the inner and outer sheets and securing
the circulating plates thereto.
When located as above described, the circulating plates 25 act to intercept the
upward passage of currents of water in the end casings beyond the lower ends of
the upper water tubes 15 of each vertical row, and to deflect said currents into the
tubes, through which they pass, exposed to the direct action of the fire, and are,
by reason of the upward inclination of the tubes, and of their tendency to ascend
when heated, delivered, at a higher level, into the water spaces of the opposite
casings, being replaced by currents of cooler water, which descend, through the
spaces between the downward projections of the circulating plates and the ends
of the casings, and thereafter ascend, through the water spaces below the
horizontal portions of the circulating plates, by which they are in turn deflected
into the lower ends of the water tubes. The inclined portions of the inner sheets
and the circulating plates provide receiving spaces diminishing in capacity from
bottom to top, and delivery spaces increasing in capacity from bottom to top, thereby
correspondingly promoting the ingress and egress of water to and from the tubes.
Feed water pipes 26, provided with ordinary check valves, and adapted to be
connected to a pump or injector, are led into the casings 1 and 2, with their
discharge ends opening thereinto below the diaphragms or circulating plates 25,
and in order to impart heat to the entering feed water, as well as to assist in
cooling those portions of the casings in which it is desired that a downward traverse
of water shall take place, the feed pipes 26, may, as shown, enter the casings 1
and 2 at their tops and extend downwardly through the same to points below the
ends of the downward portions of the diaphragms, and then be extended horizontally
towards the centre lines of the casings.
It will be obvious that as an alternative and equivalent construction, the
diaphragms 25 may, if desired, be extended entirely across the casings 1 and 2,
and communication established for the passage of water from their upper to their
lower sides by outside pipes, connected to the casings above and below the
diaphragms, into which connecting pipes the feed water pipes may be led. The
construction shown is, however, deemed preferable, in the particulars of being
within the requirements of a self contained boiler, and of affording ample space for
the downward passage of water, in the normal and desired circulation thereof
during steam generation.
While, in the constructions herein shown, the fire chamber is provided with a
lower fire grate for the combustion of solid fuel, such fire grate is not an essential
of my invention, and is not employed in cases where waste gases from furnaces,
or other gaseous fuel, is desired to be utilized in the generation of steam.
In the operation of a boiler in which the essential elements of the construction
above described are embodied, the action of the radiant heat of the ignited fuel
upon the grate, and the heat of the products of combustion thereof which pass
upwardly to the stack 11, is exerted directly upon the inner walls of the end
casings 1 and 2, the surfaces of the water tubes 15, and the lower portions of
the drums 20. The water in the end casings below the circulating plates, and
in the inclined water tubes 15, as it becomes heated, ascends through the water
tubes, and is delivered to the portions of the end casings above the circulating
plates, and thence to the drums 20, its place being supplied by colder water, which
descends in the casings through the passages between the downward projections
of the circulating plates 25 and the adjacent ends of the casings, these passages
being preferably formed, as indicated in the drawings, by extensions of the
casings beyond the grate and side walls of the fire chamber, so that they are not
exposed to the direct heat of the fire. As the cooler water passes under, and
enters the water spaces on the inner sides of the downward projections of the
diaphragms 25, it is heated, and ascending through said spaces, enters the lower
or receiving ends of the water tubes, being prevented from passing above the
upper tubes of the vertical rows by the horizontal portions of the diaphragms, as
before explained.

page_text: The active circulation thus instituted is promoted by the heat imparted to the
rising currents of water in their passage through the inclined water tubes, and is
ensured by the delivery of the feed water into a portion of the boiler from which
its natural and unopposed tendency is to ascend and pass into the receiving ends of
the water tubes.
My improvement is particularly adaptable to marine service, and to conditions
where the rapid and safe generation of steam of high pressure is required to be
effected within comparative limited space. It will be seen that under a construction
substantially as above described, a rapid and constant natural circulation of water
may be effected, with a corresponding evaporative efficiency, and that any desired
amount of grate and heating surface permitted by determined circumscribing limits
may be provided. A further feature of substantial practical advantage is the
avoidance of the numerous tube joints ordinarily found in boilers of this type, and
which are frequently so located as to be rapidly deteriorated by the direct action
of the fire, and to be difficult of access for removal and repair. The only tube
joints necessary under my improved construction are those made with the inner
sheets of the end casings, which are readily and securely made by expanding, and
are conveniently accessible without disturbing any other members, by the removal
of the oppositely located plates in the outer sheets. The large area of liberating
surface afforded by the drums, and the direct connection of the latter with the end
casings is, further, of material advantage in the prevention of priming, by promoting
the delivery of dry steam.
In the modification shown in Figs. 4 to 7, inclusive, the end casings 1 and 2 and
inclined water tubes 15, are constructed, and arranged, relatively one to the others
and to a fire and combustion chamber, in a substantially similar manner to those of
the instance first described. Where comparatively long tubes are employed, as
shown in Fig. 4, and in other cases where desirable, a central fire bridge 7ª, which
may be provided with means for the admission of air above the grates, is extended
across the fire and combustion chamber, and a grate 7 is placed on each side of the
fire bridge, said grates extending therefrom to the respective adjacent end casings 1
and 2, and being supported in the usual manner. The grates 7 are shown, in this
instance, as composed of grate bars of the ordinary form, but may, if desired, be
water grates. The lower ends of the casings 1 and 2 extend downwardly for a
sufficient distance to provide a space removed from the direct action of the fire,
for the deposition of separated impurities, which may be discharged, as from time
to time required, by suitable blow off cocks 9.
The provision of a central fire bridge and separate end grates, in the fire and
combustion chamber, enables the heat of the fuel to be fully applied to the inclined
water tubes throughout their entire length, and obviates any tendency, which
might otherwise be found, for the escaping products of combustion to escape to the
stack without exerting their calorific effect upon the entire length of the tubes
around which they pass.
The fire and combustion chamber, formed by the space between the end casings 1
and 2 and side walls 7b, is closed at top by a cap plate 10 provided with a central
exit flue or stack 11, and access to the fire chamber is had through one or more
openings 12 in the end casings, said openings being located above the grates and
provided with the usual fire doors 13. Ash pits 14 are located below the grates,
and ash pit doors 14", are provided for the regulation of draught and the removal
of ashes.
The casings 1 and 2 are, near their tops and at their ends, connected to, and
there communicate with, a steam and water receptacle or drum 20, in which, and
in the casings 1 and 2, the normal water level is maintained. As shown in the
drawings, two cylindrical drums 20 are preferably employed, one being located
above, and resting on the top of, each side wall 7b, and communicating near each of
its ends, by a lateral opening or passage in its shell, with the adjacent end casing 1
or 2. The inner face of each side wall 7b is tangential, or nearly so, to the
adjacent drum, the drums thus extending parallel with, but exterior to, the fire and

page_text: combustion chamber. The steam supply pipe 22,leading to the engine, is provided
with the usual stop valve 23, and is connected to a supplemental steam drum 20º,
which extends transversely to the drums 20, and is connected thereto by short
pipes 24.
The cap plate 10, of the fire and combustion chamber, is preferably formed of
cast iron, and forms the lower wall of a. feed water heater chamber 10%, which is
closed at top by a cap or cover 10°, extending from one drum 20 to the other.
A feed water heater 10%, of any suitable and preferred construction, may be located
in the chamber 10%, the form shown in the drawings consisting of a series of return
bends or manifolds formed in the feed water pipes 26. In order to promote the
transmission of heat to the feed water heater chamber, as well as to deflect the
heated products of combustion towards the surfaces of the upper tubes 15, a series
of downwardly extending ribs or flanges 10, is formed upon the lower side of the
cap plate 10, said ribs increasing in depth from the ends towards the central portion
of the plate, in accordance with the inclination of the tubes.
A diaphragm or circulating plate 25 is, as in the construction first described,
fitted between the inner and outer sheets of each of the end casings 1 and 2, a short
distance above the lower ends of the upper rows of water tubes 15, said plates
being preferably, as shown, located between the inwardly and outwardly bent
portions of the inner sheets of the casings, and therefore at or near the narrowest
portions of the water spaces. The circulating plates extend horizontally across
the casings from points between the outer rows of tubes and the adjacent ends of
the casings, and are then upwardly prolonged, by a vertical extension 28, at one
or both ends, to or near the openings in the shell of the adjacent drum or drums 20,
a vertical water passage 25ª, being thus provided between each of the diaphragms 28
and the adjacent end of the casing, as shown in Fig. 6. Circulating plates 27, in
or about in line with the diaphragms 28, are also fitted in the casings 1 and 2, and
extend from points adjacent to the diaphragms 25 to points slightly below the
lower ends of the lowest rows of tubes 15, so that the water passages 25° are caused
to extend from the drums to a level near or slightly below that of the lowest rows
of tubes. The several diaphragms may be connected to the inner and outer sheets
in any suitable manner.
When located as above described, the circulating plates 25 and 27 act to
intercept the upward passage of currents of water in the end casings beyond the
lower ends of the upper water tubes 15 of each row, and to deflect said currents
into the tubes, through which they pass, exposed to the direct action of the fire,
and are, by reason of the upward inclination of the tubes, and of their tendency
to ascend when heated, delivered, at a higher level, into the water spaces of the
opposite casings, being replaced by currents of cooler water, which descend through
the passages 25, and thereafter ascend through the water spaces below the
diaphragms 25 and between the diaphragms 27, by which they are, in turn,
deflected into the water tubes. The diaphragms 28 divide the downward currents
of cooler water from the upward currents of hotter water passing out of the upper
ends of the tubes 15, and prevent interference of these respective currents, one with
the other, a substantially continuous passage being provided for the currents of
cooler water from the drums 20 to the lower portions of the end casings 1 and 2.
The feed water pipes 26 are preferably connected with feed water heaters 10ª,
as before described, and extend below the lower vertical diaphragms 27, so as to
deliver the feed water into the coolest portions of the boiler, and at points where
it most readily tends to enter the lower ends of the water tubes 15.
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, in a steam boiler, of two end casings or legs, an upper steam
receptacle connected to said casings, inclined water tubes connecting said casings,

page_text: and a diaphragm or circulating plate located in one of said casings above the lower
ends of the water tubes. substantially as set forth.
2. The combination, in a steam boiler, of two end casings or legs, an upper steam
receptacle connected to said casings, oppositely inclined water tubes connecting
said casings, and a diaphragm or circulating plate located in each of said casings
between the lower ends of the tubes which are inclined in one direction and the
upper ends of the tubes which are inclined in the other direction, substantially as
set forth.
3. The combination, in a steam boiler, of two end casings or legs having portions
of their inner sheets inclined relatively to their outer sheets, an upper steam
receptacle connected to said casings, inclined water tubes connected at opposite
ends to the inclined portions of the inner sheets of the casings, and diaphragms or
circulating plates located in each of said casings above the upper and below the
lower ends, respectively, of the water tubes, so as to provide receiving spaces
diminishing upwardly in capacity, and delivery spaces increasing upwardly in
capacity, substantially as set forth.
4. The combination, in a steam boiler, of two end casings or legs, an upper
steam receptacle connected to said casings, inclined water tubes connecting said
casings, a diaphragm or circulating plate located in one of said casings above the
lower ends of the water tubes, a water passage connecting the spaces above and
below the circulating plate, and a feed water pipe leading into the space below the
circulating plate, substantially as set forth.
5. The combination, in a steam boiler, of two end casings or legs, an upper steam
receptacle connected to said casings, inclined water tubes connecting said casings,
a diaphragm or circulating plate located in one of said casings above the lower
ends of the water tubes, a downwardly projecting extension connected to either or
both ends of the circulating plate and forining the inner wall of a water passage
connecting the spaces above and below the horizontal diaphragm, and a feed water
pipe leading into the space below the diaphragm, substantially as set forth.
6. The combination, in a steam boiler, of two end casings or legs, an upper steam
receptacle connected to said casings, an interposed combustion chamber of less
width than said casings, inclined water tubes connecting said casings, a horizontal
diaphragm or circulating plate located in one of said casings above the lower ends
of the water tubes, a downwardly projecting extension connected to either or both
ends of the circulating plate and forming the inner wall of a water passage in the
portion of the casing projecting beyond the combustion chamber, which passage
connects the spaces above and below the horizontal circulating plate, and a feed
water pipe leading into the space below the diaphragm, substantially as set forth.
7. The combination, in a steam boiler, of two end casings or legs, inclined water
tubes connecting said casings, a transverse diaphragm or circulating plate located
in one of said casings above the lower ends of the water tubes, and a vertical
diaphragm or circulating plate extending between the transverse diaphragm and
the upper portion of the casing, substantially as set forth.
8. The combination, in a steam boiler, of two end casings or legs, oppositely
inclined water tubes connecting said casings, a transverse diaphragm or circulating
plate located in each of said casings between the lower ends of the water tubes
which are inclined in one direction and the upper ends of the tubes which are
inclined in the other direction, and vertical diaphragms or circulating plates
extending between the transverse diaphragms and the upper portions of the casings,
substantially as set forth.
9. The combination, in a steam boiler, of two end casings or legs, an upper
steam and water receptacle connected to said casings, a transverse diaphragm or
circulating plate located in one of said casings above the lower ends of the water
tubes, and a vertical diaphragm or circulating plate extending from said transverse
diaphragm to or near an opening in the steam and water receptacle, substantially
as set forth.

page_text: 10. The combination, in a steam boiler, of two end casings or legs, inclined water
tubes connecting said casings, a transverse diaphragm or circulating plate located.
in one of said casings above the lower ends of the water tubes, and vertical
diaphragms or circulating plates extending between the transverse diaphragm and
the upper and lower portions, respectively, of the casing, substantially as set.
forth.
11. The combination, in a steam boiler, of two end casings or legs, inclined
water tubes connecting said casings, a fire and combustion chamber enclosed by
said casings and by side walls and a cap plate extending between them, an upper-
steam and water receptacle connected to and communicating with the outer ends of
said casings, so as to be substantially exterior to the fire and combustion chamber,.
inclined water tubes connecting said casings, a transverse diaphragm or circulating
plate located in one of said casings, above the lower ends of the water tubes, and a
vertical diaphragm or circulating plate extending from said transverse diaphragm
to or near an opening in the steam and water receptacle, substantially as set.
forth.
12. The combination, in a steam boiler, of two end casings or legs, inclined
water tubes connecting said casings, a fire and combustion chamber enclosed by said
casings and by side walls and a cap plate extending between them, an upper steam
and water receptacle connected to and communicating with the outer ends of said
casings, so as to be substantially exterior to the fire and combustion chamber,.
inclined water tubes connecting said casings, a transverse diaphragm or circulating
plate located in one of said casings, above the lower ends of the water tubes, and
vertical diaphragms or circulating plates extending between an opening in the
steam and water receptacle and the lower portion of the casing, so as to form a
water passage, between the outer row of tubes and the adjacent end of the casing,.
from the steam and water receptacle to a level below the lower rows of tubes,
substantially as set forth.
13. The combination, in a steam boiler, of two end casings or legs, inclined water
tubes connecting said casings, a fire and combustion chamber interposed between
said casings, and a feed water heater chamber located above the fire and combustion,
chamber, substantially as set forth.
14. The combination, in a steam boiler, of two end casings or legs, inclined water
tubes connecting said casings, a fire and combustion chamber interposed between.
said casings, a feed water heater chamber located above the fire and combustion
chamber, and a series of ribs or deflecting plates projecting downwardly from the
cap plate of the fire and combustion chamber, substantially as set forth.
15. The combination, in a steam boiler, of two end casings or legs, inclined water
tubes connecting said casings, a fire and combustion chamber interposed between.
said casings, a feed water heater chamber located above the fire and combustion
chamber, a feed water heater in said chamber, and a feed water pipe connected to
said heater and discharging into the lower portion of one of the casings, substantially
as set forth.
16. The combination, in a steam boiler, of two end casings or legs, inclined water
tubes connecting said casings, a fire and combustion chamber interposed between
said casings, a transverse fire bridge located in the fire and combustion chamber-
below the water tubes, and two fire grates, each extending from one side of the fire
bridge to the adjacent end casing, substantially as set forth.
Dated. at Pittsburg, Pa., U.S.A., this Ninth day of December A.D. 1892.
Witnesses:
J. SNOWDEN BELL.
F. E. GAITHER.
HENRY A. LAUGHLIN.