Marine Boiler Improvements.
Year: 1894

page_text: Date of Application, 1st Jan., 1894
Complete Specification Left, 20th July, 1894-Accepted, 22nd Dec., 1894
PROVISIONAL SPECIFICATION.
Marine Boiler Improvements.
THOMAS WILLIAM BAILEY 5 Alexandra Road Newport Mon. Marine
Engineer do hereby declare the nature of this invention to be as follows:-
A hot air supply to furnaces Construction of the fire bed An additional supply
of condensed water to the boilers and the circulation of the water at the bottom of
main boilers which is effected in the following manner.
A
A multitubular boiler cylindrical shaped having the furnace tubes running
through the boiler from the front of boiler to the back of boiler. The front
plates of boiler forming the front tube plate. The back plates of boiler forming
the back tube plate. The small tubes above the furnace tubes running through
the whole length of boiler from the front tube plate to the back tube plate. The
back tube plate to be divided into two series of tubes a lower and upper series of
tubes. Two built chambers fixed on to the back tube plate. A lower and
upper chamber so dividing or forming the lower and upper series of tubes.
supplementary boiler having a steam dome. This supplementary boiler running
across the back end of main boiler and abutting on main boiler end and partly
closing the back end of furnace tubes so forming the bottom of the lower series
of tubes chamber before mentioned The upper tube chamber at the back end of main
boiler opening out into an uptake chamber at the base of funnel and on the top of
uptake chamber. A series of tubes placed and built as part of the structure of
the uptake chamber and the funnel. These series of tubes at base of funnel to be
encased in on the sides forming a chamber around the outside of these series of
tubes The top tube plate forming the top of the chamber The bottom tube
plate forming the bottom of chamber with openings at each end of chamber for
admission and exit of air This chamber being entirely seperated from the uptake
chamber each having distinct duties.
A little below the water level of main boiler the main boiler to be enclosed in a
built chamber This chamber enclosing the shell plates of main boiler from just
below the water level on one side of the boiler to just below the water level on the
other side of the boiler. This chamber projecting beyond the front of main
boiler and enclosing the mouths of the furnace tubes at front of boiler. This
chamber also to be continued beyond the back end of main boiler and beyond the
supplementary boiler at back of main boiler and rising up vertically beyond the
lower and upper tube chambers at back end of main boiler rising up above these
chambers and continued up above the uptake and merging into and communicating
into the exit opening in the chamber surrounding the outside of tubes at base of
funnel.
The funnel to be enclosed part of the way up in its length and all around its
circumference by a casing forming a chamber around funnel but open at the top.
This funnel casing or chamber to be continued downwards merging into and
communicating with the admission opening in chamber outside the series of tubes
at base of funnel so forming a continuous enclosure or chamber from funnel
casing to the mouth of furnace tubes at front of main boiler.
Outside this continuous enclosure or chamber a series of metal plates to be
fixed on to this continuous chamber structure not in actual contact but separated

page_text: by distance ferrules so affording the admission of the surrounding air around
this continuous enclosure or chamber, these plates to rise up above the top of the
continuous enclosure or chamber.
On the front of main boiler a smoke box or flame chamber to be fixed completely
enclosing the whole series of flame tubes at front of main boiler forming a
completely enclosed front tube chamber with suitable doors in front to admit of
tube sweeping. These doors to have outside plates attached to them not in actual
contact but seperated by distance pieces or ferrules for admission of the surrounding
air outside the smoke box door plates.
Over these several structures and above the series of tubes at base of funnel a
box shaped chamber to be erected. The sides of this box shaped chamber to be
continued downwards and to abut on to the series of plates forming the air passages
outside the plates forming the continuous enclosure or chamber before mentioned.
The front side of this box shaped chamber to abut on to the outside plates
forming the air passage outside the smoke box door in front of main boiler.
In the funnel an air blast apparatus to be fixed connected to an air fan or
blowing engine discharge so to increase the upward draught in funnel when the
blowing engine is at work.
The furnaces to be fire brick or slag brick built step shaped built along the length of
the furnace tubes Two series of steps One series of steps commencing from one side
of the furnace tube The other series of steps commencing from the other side of the
furnace tube. The two series of steps meeting and joining at the bottom of the
furnace. This construction of the furnaces is necessary as the supply of hot air
to ordinary fire bar furnaces would melt the fire bars.
The working action of the invention will be as follows. When the main boiler
and the supplementary boiler at the back end of main boiler are filled with the
required water and fires alight in main boiler furnaces the flame radiant heat
and heated gases passes from the furnaces through the furnace tubes impinging on
the top of supplementary boiler passing into the lower tube chamber at the back
of main boiler then through the lower series of tubes into the smoke or flame
chamber at front of main boiler from thence through the upper series of tubes into
the upper tube chamber at back of main boiler from thence up the uptake then
up through the series of tubes at the base of the funnel then up through the funnel
to the atmosphere. The working action of the heated air supply to the furnaces as
follows. The atmosphere passes into the casing or chamber around the outside of
funnel thence downwards through the admission opening of chamber outside the
series of tubes at base of funnel passing around outside these series of tubes thence
through the exit opening into that portion or part of the continuous enclosure or
chamber over the uptake. This supply of air is further increased by additional
air passing upwards through the passages formed by the series of plates outside
the continuous enclosure or chamber around main boiler also by additional air
passing upwards through the passage formed by the outside plates on smoke box or
Hame chamber doors at front of main boiler. These additional supplies of air
passes over the top of main boiler into a suitable opening at the top of the
continuous enclosure or chamber over the uptake mingling with the current of air
passing from the tube chamber at the base of funnel This combined supply of air
passing downwards past the outside of the top tube chamber at the back of main
boiler downwards past the outside of the bottom tube chamber at back of main
boiler. This supply of air has now become heated by contact with the heated
parts of the structure in its passage. It then passes downward under the bottom
of supplementary boiler at back of main boiler thence under the bottom and along
the sides of main boiler in direct contact with the shell plates of main boiler
causing by this direct contact a circulation of water in the interior of the bottom
part of main boiler.
This heated supply of air finally passes on to the furnaces at
front of main boiler through the enclosure at furnace fronts.
The working action of the additional condensed water supply to main boiler is
as follows. The radiant heat flame and heated gases after passing through main

page_text: boiler furnace tubes impinges on the plates forming the top of the supplementary
boiler in its passage through to the lower tube chamber at back of main boiler.
This contact of the radiant heat flame and heated gases with the plates of
supplementary boiler generates steam in the supplementary boiler. The steam
generation in the supplementary boiler is assisted or increased by the main boiler
furnace hot air supply in its passage under the bottom of supplementary boiler.
The steam thus generated by the radiant heat flame and heated gases and hot air
supply is conducted by suitable means from the steam dome of supplementary
boiler to one of the slide valve chambers of the main engines to assist in the
working of the main engines. After its efficiency has become exhausted it enters with
the exhaust steam of main engines into the condenser from thence in the form of
condensed water pumped into main boiler or into the supplementary boiler as the
occasion requires.
Suitable and necessary valves cocks and boiler fittings to be placed on
supplementary boiler for complete and proper working of the same.
All the structures passages chambers furnace construction supplementary boiler
and the several series of tubes fittings &c. hereto named in this Specification
working and acting in combination to effect the well being and proper action of the
improvements embodied in the invention whereby I append my signature.
Dated this Thirtieth day of December 1893.
T. W. BAILEY.
THOMAS WILLIAM BAILEY 5 Alexandra Road Newport Mon. Marine
Engineer 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 :-
A hot air supply to furnaces, construction of the fire bed, an additional supply
of condensed water to the main boiler.
Circulation of the water at the bottom of main boiler, and other improvements;
which are effected in the following manner;
A multitubular boiler cylindrical shaped, having the furnace tubes running
through the boiler from the front of boiler to the back of boiler, with no internal
combustion chamber.
The front plates of boiler, forming the front tube plate. The back plates of
boiler, forming the back tube plate. The small tubes, above the furnace tubes,
running through the whole length of boiler, from the front tube plate to the back
tube plate. This back tube plate to be divided into two series of tubes, a lower,
and upper series of tubes. Two built chambers fixed on to the back tube plate, a
lower and upper chamber; so dividing or forming the lower and upper series of
tubes.
A supplementary boiler, cylindrical shaped, having a steam dome. This
supplementary boiler, running across the back end of main boiler, and abutting on
main boiler end, and partly covering or closing the back ead of furnace tubes; so
forming the bottom of the lower series of tube chamber, before mentioned.
The upper tube chamber, at the back end of main boiler, opening out into an
uptake chamber at the base of funnel, and on the top of uptake chamber a series
of tubes placed and built as part of the structure of the uptake chamber and the
funnel. These series of tubes, at base of funnel to be encased in on the sides,
forming a chamber, around the outside, of these series of tubes. The top tube
plate forming the top of the chamber. The bottom tube plate forming the bottom
of the chamber, with openings at cach end of chamber for admission an exit of

page_text: air, this chamber, being entirely separated in its action, from the uptake; each
having distinct duties.
At a little below the water level of main boiler, the main boiler to be enclosed in
a built chamber; this chamber enclosing the shell plates of main boiler from just
below the water level, on one side of the boiler to just below the water level on
the other side of the boiler. This chamber projecting beyond the front of main
boiler and enclosing the mouths of the furnace tubes, at front of main boiler.
This chamber, or enclosure, also to be continued, beyond the back end of main
boiler, and beyond the supplementary boiler, at back of main boiler, and rising up
vertically beyond the lower and upper tube chamber, at back end of main boiler;
rising up above the uptake, and merging into, and communicating into the exit
opening, in the chamber surrounding the outside of the tubes at base of funnel.
The funnel to be enclosed part of the way up, outside, in its length and all around
its circumference, by a casing forming a chamber around funnel, but open at the
top. This funnel casing, or chamber to be continued downwards, merging into, and
communicating with the admission opening in chamber, outside the series of tubes
at base of funnel; so forming and being part of a continuous enclosure, or chamber,
from funnel casing to the mouth of furnace tubes, at front of main boiler; outside
this continuous enclosure, or chamber, metal plates to be fixed on to this continuous
chamber structure, not in actual contact, but separated by distance ferrules; so
affording the admission of air around the outside of this continuous enclosure or
chamber.
On the front of main boiler, a flame chamber to be fixed; completely enclosing
the whole series of flame tubes at front of main boiler; forming a completely
enclosed front tube chamber, with suitable doors in front to admit of tube sweeping.
These doors to have outside plates attached to them, not in actual contact, but
separated by distance ferrules for admission of air, outside the smoke box door plates.
Over all these several structures, and above the series of tubes at base of
funnel, a box shaped chamber to be erected; the sides, of this box shaped chamber,
to be continued downwards, and to abut on to the series of plates forming the air
passages, outside the plates forming the continuous enclosure, or chamber, before
mentioned. The front side, of this box shaped chamber, to abut on to the outside
plates forming the air passages, outside the smoke box doors, in front of main
boiler. In the funnel an air blast apparatus to be fixed, connected to an air fan or
blowing engine discharge; so to increase the upward draft in funnel, when the fan
or blowing engine is at work.
The furnaces to be fire brick lined, or of some fire resisting substance, built step
shaped, built along the length of the furnace tubes two series of steps, one series
of steps, commencing from one side of the furnace tube, the other series of steps
commencing from the other side of the furnace tube; the two series of steps
meeting opposite each other, at the bottom of furnace, leaving a gutterway or
channel along the whole of this built furnace.
DESCRIPTION OF DRAWINGS.
Figure 1. represents a front view of the main boiler, and a front sectional view,
of the continuous enclosure.
Figure 2 represents a longitudinal sectional view of main boiler.
Figure 3 represents a back end view of main boiler; shewing a longitudinal
sectional view of supplementary boiler.
Figure 4 represents a longitudinal view of main boiler; shewing a sectional view
of one water box.
Figure 5. a back end view of main boiler; shewing a sectional view of the water
boxes on each side of the boiler; also shewing the water tubes in connection with
the water boxes.

page_text: A, Figures 1, 2, 3, 4, & 5, represents the main boiler.
A, Figure 2 shews the flame tubes and furnace tubes, running through the boiler
from end to end, with no internal combustion chamber.
B, Figure 1. An iron built furnace, built in furnace tube and lined with fire
brick, or a fire resisting material, so to protect the iron built furnace structure; to
be step formed, on each side, longitudinally, having a central gutterway for
admission of air; the whole length of the fire. Loose, shiftable, bars in front laid
flat ways down, and supported on projecting ledges, on fire bar structure supports.
A central opening left in this fire bar structure support, in communication to the
furnace gutterway, already mentioned. Two rows of fire bars, one row on each
side of this said central opening.
These bars simply to keep the fire from falling out, and placed widely apart.
The fire bar structure in front to be some little distance, from the step formed
furnace structure. The fires would be nearly constantly burning hollow, induced
by the step formed structure, so a free supply of air would be admitted, accelerated
by the induced draft in funnel. In the present type of bar furnace, now in use,
the fires are periodically cleaned, and long before the time of each periodical
cleaning, the fires are thickly coated with clinker. Ash pits, darkened, especially
at the back that repeated use of the pricker blade fail to give a desired result;
thereby, shewing a faulty admission of air, and so an improper combustion of fuel,
I am led by these several faults, as well as for the better application of the hot air
supply to furnaces. To adopt this step formed furnace structure, as with this
structure, and hot air supply, very little clinker will form, and therefore termed
it an improvement; the design is intended for a short and deep fire.
C, Figure 2. The remaining portion of furnace tube, and in its capacity, accele-
rating the combustion of the gases.
D, Figure 2. A lower tube chamber with the top of supplementary boiler, R,
forming the bottom of the chamber; the top of this lower tube chamber, formed
by several water tubes, Figures 4 & 5, these water tubes, debouching into water
boxes, at each side of main boiler, these water boxes, partly forming the sides of
the chamber. The remaining portion of sides to be completed by an iron
construction, also the top of water tubes to be covered in, and this covering, to be
carried down the back, to the top of supplementary boiler, R, so forming a
completely enclosed bottom tube chamber, suitable doors, and baffle plates, where
necessary. This lower tube chamber divides the main boiler flame tubes, into two
series of tubes. Now, with the ordinary tubular boiler, with internal combustion
chamber, the lower rows of tubes, only, spout out flame, which is lost in transit
to the funnel. The idea of two series of tubes, and external combustion chamber,
is an endeavour to fill both series of tubes with flame; by this means, and by an
introduction of a small supply of air into flame box F, Figure 2, at front of boiler,
also induced by the induced draft in funnel, to effect the same purpose.
the radiant heat, escaping from chamber D structure, is utilized to set up conduction
of heat, in shell plates of main boiler, and giving a higher temperature in furnace
tubes, where the most of the steam generation takes place.
Also
E, Figures 4, & 5, shewing several water tubes, placed horizontal across the back
end of main boiler, and forming the top of the lower chamber D. These water tubes
passing into water boxes, fixed on each side of the back end of main boiler, as
shewn on Figure 15. A pipe communication, from the bottom of main boiler to
one of the water boxes, and another pipe communication to the other water box,
from the top of main boiler; so providing for a circulation of water and steam
through the water boxes, and water tubes; plug holes left opposite each tube for
tube expanding, and tube cleaning; as the water in main boiler will be quite under
scale control, it will be seldom necessary to clean these tubes.
F, Figure 2. A flame box of the ordinary smoke box type; but having no outlet
at top, air circulating plates attached, outside, to the doors and structure for the
passage of the radiant heat, upwards.
G, Figure 2. An upper tube chamber at back end of main boiler, with an outlet

page_text: at top to uptake. At the bottom of the side of this chamber, an orifice left, with a
closed shoot attached, leading to alley way for ready clearance of soot. At the
back of this chamber, outside of it, an air circulating passage plate attached, for
the passage of air down the back of this chamber into the space left between the
top of the tube chamber D, and bottom of the chamber G.
H, Figure 2. The uptake.
I, Figure 2. A series of tubes over uptake, H, passing through a lower and
upper tube plate; these series of tubes enclosed in, on the sides, forming a chamber
around these series of tubes; the whole area of tube orifice to be about one and a
half times the funnel orifice.
J, Figure 2. The funnel. To be of greater length and smaller diameter than usual.
The casing L. will take off the meagre appearance of funnel.
K, Figure 2. An air blast pipe with a spreader attached, this pipe connected to
a blowing engine or fan, driven from main engines and driven by an auxiliary engine,
when main engine stopped. As with main engines developing, say 1000 1.H.P.
a few horse power is not missed from the total power, whereas the steam, to constantly
drive an auxiliary engine, would be of greater cost.
L, Figure 2. A casing around the outside of funnel, only a part of the way up
the funnel, open at the top with an overhanging hood, to prevent rain and spray
from entering casing. This casing, partially closed at the bottom, open only at the
forward part, for the admission of air to the forward part of chamber, M, around
the series of tubes I.
M, Figure 2. A chamber enclosing the series of tubes I, at base of funnel,
having an air admission opening at one end, and an exit opening at the
other end.
N, Figure 2. A continuous chamber, or enclosure, formed by a casing, partly
around main boiler in structure, thus-double tee iron secured longitudinally on
main boiler, at a little below the water level of boiler; from this double tee iron,
single tee iron running downwards, in a straight line, continuing under the bottom
of boiler and rising vertically upwards and connected to the double tee iron, at the
other side of main boiler; so forming a frame; several of these frames along the
length of the boiler, secured to the double tee iron on each side of boiler. These
several frames to hold several courses of plates; these plates bolted to the tee iron
frames, and jointed with asbestos putty or other medium, to secure a fairly air-tight
structure, to further support the structure the tee iron frames, to be stayed to the
ballast tank top, or to the angle irons. The whole structure to be of light material,
consistent with the necessary strength required, and forming a square shaped
chamber. This shape giving freedom for examination, caulking, repairs &c. This
chamber continued beyond the front of main boiler, and enclosing the ash pits of
furnace tubes; this chamber also continued beyond the back end of main boiler,
and beyond the supplementary boiler "R" rising vertically, upwards, above the
uptake, and communicating with the chamber "M" suitable doors to be placed
where necessary.
This continuous chamber, or enclosure, forming a direct com-
munication from L, & T, to B. This chamber, or continuous enclosure to have
light plates attached to its structure; forming an air passage, outside this
continuous chamber or enclosure and lettered S" on drawing; so affording a
means of the radiant beat, from engine room, and stokehold, and from the plates
forming the structure, being conveyed by this channel to the opening "T" leading
to "N." These outside plates to abut on to the ordinary structure, generally built
over main boilers, which may be termed the "boiler top room." By this abutting
of the plates, the circulation of air is rendered more efficient; by this means also
no heat is lost, but is picked up from all parts and conveyed to the fires, by the
means of the opening at T. The crown of main boiler to be covered where
required, from Y Fig. 3 on one side to Y Fig. 3 on the other side, with a good
non-conducting composition, and this composition to be covered with thick sheet
lead. The continuous chamber or enclosure "N serves not only the purpose of
conducting the heated air to furnaces; the following illustration will serve to shew
50
"

page_text: another purpose, or effect. The marine boiler, ordinary type, when under way at
sea compound, or triples boilers, steam, on pressure guage between ten or twenty
pounds below the blowing off pressure; a sudden order for stoppage of engines,
without due warning, main and ash pit dampers are shut, steam still rising; as a
further precaution the smoke box doors are opened; now the air, that is admitted
through the smoke box doors, does not come in contact with the boiler to alter the
temperature of the plates, but acts as a draft check, and therefore a combustion
check; say now, the steam is now at a standstill, which it generally is or very slowly
rising; the temperature, in the furnace tubes combustion chamber, and flame tubes,
is still at a high temperature, fires fairly bright. Now this temperature, is the
temperature, necessary to keep the steam at a standstill; owing no doubt to external
radiation and other causes. This loss is a constant, and going ou the whole of the
steaming period of the voyage, and further increased as the full speed temperature
is arrived at; so the continuous chamber, or enclosure, being an envelope of heated
air, serves also the purpose of checking external radiation, which is a direct gain in
itself, and setting up conduction of heat through the boiler shell plates, a double
gain thereby taking place, also, circulation of the water at the bottom of the boiler
takes place. A boiler so constructed no loss of heat takes place other than up the
funnel and wherein, I considered an improvement, and no doubt an economy of fuel,
to a large extent.
P, Figures 1, & 3. Two doors of sufficient size, hinged fixed, placed at the base
of funnel, over the series of tubes I. A chain communication from each door to
overhead wheel, from thence to engine room, for use when engines are stopped and
steam rising.
R, Figure 3. A supplementary boiler, cylindrical type, of sufficient diameter to
permit a man lying down in its length, to scale the interior. This supplementary
boiler to extend along the back end of main boiler, partly covering the furnace tube
orifices, and so forming the bottom of the chamber "D." The chamber D Fig. 2
being built on to R. R to have a steam dome of sufficient height to admit of the
dome being half filled with water, in sufficient quantity for working use. In the
case of two main boilers, the length of "R" can be curtailed in length, to partly
cover one or two furnace tube ends of each main boiler; in that case, the dome
might be placed midway in the length of "R" as deemed the best position; R to
be fitted with all necessary cocks, valves, sight, salmometer &c.; the check valve
box on R to be connected to main engine feed, and to the sea, for use as required.
The steam pipe from the dome to have one or more non return valve boxes attached,
for the conveyance of steam, either to main boiler or to one of the slide valve
chambers of main engines.
S, Figures 1, 2, & 3. An air passage, formed by plates attached outside any
heated plates in the whole structure, and abutting on the boiler top room plates.
These air passages carrying the radiant heat from the inner plates, also heat from
engine room and stokehold, up through these air passages up to orifice T Figure 2
the passage marked S Figure 2 at back of tube chamber G for circulating a
current of air into, and in contact with the tube chamber division structure,
between D and G.
T Figure 2. The raised orifice for receiving the heated air from air passages S
and conveying to N.
Y Figure 2. The double tee iron secured to main boiler on each side, at a little
below the water level in main boiler, running along the length of main boiler from
end to end, and for fixing the tee iron framing to, on which the plates are bolted to
form the chamber N.
From Y Figure 3 to supplementary boiler R Figure 3 that part of the continuous
chamber or enclosure lettered N above the supplementary boiler R to be closed up
by an iron plate, each side of main boiler end to be similarly closed as above stated;
so that the hot air for furnace supply may all pass outside the back of chambers G
and D and under the bottom of supplementary boiler R, giving thereby a more

page_text: uniform temperature to the hot air than would otherwise be if the said parts of the
continuous chamber N were left unclosed.
A further description of tube chamber G at back of main boiler will be readily
understood; G to be constructed in like manner as the smoke boxes on the ordinary
cylindrical marine boiler now in use, and G to be connected to the uptake in like
manner as these said smoke boxes are connected to the uptake in marine boilers of
multitubular kind, with the exception of the doors being placed at the sides instead
of at the back.
The working action of the steam generation, as follows; Figure 2. The flame
and radiant heat passes from B, to C, entering lower tube chamber D, impinging in
transit on the top of supplementary boiler R; then through the lower series of
tubes to flame box F, here receiving, if necessary, a little additional air, then
through the upper series of tubes into the upper tube chamber G, then through
uptake, then through the series of tubes I, at base of funnel, then through funnel to
atmosphere, accelerated in its passage by the air blast "K."
The working action of the hot air supply to furnaces, as follows; Figure 2. The
air passes down "L" into "M" passing around and among the outside of the
tubes 1, to N, mingling with the air from engine room and stokehold, which passes
through the passages "S" absorbing radiant heat from the heated plates in transit,
to orifice T. The volumes of air mingling together, pass into N downwards, in
contact with back of heated tube chambers "G" and "D." The air, now finally
heated, passes under the supplementary boiler "R," then under the bottom and
along the lower part of the sides of main boiler, causing circulation of water in main
boiler, where this hot air supply impinges, then on to furnaces B. By a simple
arrangement, hot air can be circulated around main engine cylinders, and slide valve
chambers, from 300 to 700 degrees of temperature, at the will and control of the
engineer in charge.
The working of the additional condensed water supply, as follows; Figure 2.
The steam generated in supplementary boiler R passes either into the main boiler,
or to one of the main engine slide valve chambers, at the will of engineer in charge,
and according to the pressure of steam in supplementary boiler "R" at the time,
thereby assisting the working of main engines in either case, then after, in the usual
manner, to condenser. The condensed water pumped into main boiler, or supple-
mentary boiler, or to both just as required. The additional sea water required
for R, given to R by any suitable arrangement. Now with this additional
condensed water supply to main boiler, the main boiler can be started with fresh
water, the water kept fresh or salted at will, or the main boiler can be started with
sea water, kept at that density, or reduced in density, at the will of the engineer in
charge; as the additional condensed water supply is ample for any requirement, so
by this means the formation of scale in main boiler is under perfect control.
The main boiler can be kept without scale, or with a slight coating of scale, just
at will, which I have considered an improvement. The supplementary boiler "R,"
to be scaled in like manner as the jet condenser boilers of years ago.
Now with this design of boiler, having no scale formation, no loss of heat
whatever, a better or more complete combustion of fuel, no accumulation of ashes,
all consumed; a saving should ensue; and economy of fuel means less cost, and
more cargo carrying capacity, which is a consideration to steam ship owners.
Whereby the means to carry out these and other advantages I have termed
improvements, also this design of boiler would be available to carry 200 lbs.
pressure, or more, to the square inch (working pressure).
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 cylindrical shaped, multitubular, marine boilers, the flame tubes, and the
furnace tubes, running through the boiler from end to end, with no internal

page_text: combustion chamber; but with a combustion chamber, or combustion chambers
externally.
2. A supplementary boiler, at the back end of all multitubular, marine boilers,
having the furnace tubes running through from end to end.
3. For a structure forming an enclosed air passage, running down the back end
under the bottom, and along the sides of main boiler to the furnaces, in direct
communication, as described; with any hot air heating apparatus above the top of
main boiler.
4. For a step shaped furnace structure, lined with any suitable fire resisting
material, and having the fire bar structure in front, as described in Specification.
5. For the arrangement or structure, as described in Specification, for conveying
the heat of engine room, and stokehold, to a convenient channel for conveyance to
furnaces.
T. W. BAILEY.