Year: 1888

page_text: I PATRICK FRANCIS DUNDON of Dundon's San Francisco Boiler Works Nos. 314.
to 318 Main Street San Francisco California in the United States of America
Boiler Maker, 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 consists of a combination of the Cornish boiler and the cylinder
tubular boiler which is constructed in the following manner the Cornish boiler has an
outer cylindrical shell (A) and a large interior flue (B)-This flue is used as a furnace
and is placed eccentrically to the outer shell as shewn at Figs. 1. 2. 3. 4. 6 and 7 of
the accompanying drawings so as to leave a space of say about 4" at the bottom
between the furnace and the shell and a space of say about 16" above between the
furnace and the shell-This latter space is for the purpose of having a solid body of
water over the fire and also to leave sufficient room for a man hole so as to afford
proper facilities for examining clensing and repairing the boiler when necessary.
Directly over the outer shell (A) which surrounds the furnace another cylindrical
shell (C) is placed This shell contains the return tubes (d) A space of say about 6"
is left between the two shells (A) (C) which are connected together by one or more
flanged nozzles or sleeves (e) Figs. 1. 2. 3. 4. 5. 6 and 7. These nozzles or sleeves
are rivetted to each shell and are large enough to allow a man to pass through in
order to examine or clean the lower part of the upper shell (A) which is under the
return tubes (d) Both the upper and lower shells (A) (C) are connected together at
the rear end by an upright cylindrical shell (g) and when so connected they form two
right angled elbows (h, h,) Fig. 2 at the rear end of the boiler.
I would here observe that I prefer to cut off the right angled corner at the lower
corner as shewn in Fig. 2 of the drawings and fit it with a separate plate (I) of a
curvilinear shape so as to make it more of a round corner the advantage of so doing
being to produce a perfect circulation of the water from the bottom of the boiler and
also to afford a better opportunity for cleaning out the ashes from behind the grates
and reduce the liability to wear away by corrosion The plate (I) when so fitted in is
placed at an angle of about 135° to the vertical shell (9) and the bottom horizontal

page_text: shell (A) All the flanged corners are made very round and of not less than a
3" radius It must also be understood that all the cylindrical shells are of a circular
cylindrical form A combustion chamber (J) is provided at the rear end of the
furnace. This combustion chamber consists of a circular cylinder which is set at
right angles to the furnace while the bottom corner at the rear end is fitted with
a curved plate (k) in the same manner as already described with respect to the
bottom corner of the outer shell-On the upper front side is a flat surface (L) equal
in size to the space occupied by the tubes (d) and of a similar confirmation to the
space occupied by the tubes themselves at the point where they are connected All
the other portions of the combustion chamber however except this are formed either
in circles or in segments of circles so as to give the greatest degree of strength and
also to reduce the necessary staying or bracing to a minimum When a single boiler
is employed the steam drum (M) is placed at the front of the boiler with the bottom
of its shell slightly above the top of the upper tubes and resting on and attached to
braces (¹) which are attached to and project from the upper shell as shewn at
Figs. 1. 2. and 10 of the accompanying drawings-When however two or more
boilers are employed conjointly as shown at Fig. 3 the steam drum or steam drums is
or are placed parallel with and between the upper shells (C) and such steam drum or
drums rest upon straps (1) attached to both shells one or more straps (m) being placed
over the steam drum or drums and attached to them and also to the upper shells as
shewn at Fig. 3-When the boiler is to be used for marine purposes suitable eyes (m³)
Fig. 3 are formed on the ends of the straps which eyes are attached to suitable
fastenings in the ship The drum is furnished with proper steam connections (o)
Figs. 2. 3. 4. and 7 which connect it with the boiler and also with suitable drain
pipes P Figs. 2. 3. 4.-The boiler having been constructed in the manner hereinbefore
described the smoke box (9) Figs. 2 and 10 is formed at the front over the ends of
the return tubes (d) and fastened to the front side of the drum (M) A jacket (r)
Figs. 1. 2. 3. 10 hereafter termed the "flame jacket" made of any suitable light iron
or plate is then fitted all round the boiler or boilers-This jacket terminates at and
is connected to the boilers along the sides of the upper shells just below the water
line as shewn at Figs. 1. 2 and 3 and is provided with a base (f) Figs. 2, 10 to serve
for a chimney which chimney has a proper outlet at the rear end The sides of
the smoke box at the front are connected to the flame jacket-The space between the
jacket and the boilers is regulated by the area requisite to afford a free draught to
the chimney thus it is obvious that the heat and other products of combustion pass
from the grates along the furnace to the combustion chamber (J) Figs. 1. 2. 4. 5. 6. 7. 10
from whence they are conducted through the tubes (d) to the front of the boiler
where they come in contact with the steam drum (M) and so superheat the steam
contained therein-They are then conveyed along and around the outside of
the boilers and between them and the flame jacket to the chimney (f) at the
rear end.
It will be readily seen that boilers constructed according to my invention possess
many decided advantages over the ordinary type of boiler generally used for marine
purposes at the present time-Such advantages may be briefly summarised as
follows viz.
1° My improved boiler obviates all necessity for a very large shell to contain both
furnaces and return flues in one as heretofore required.
2° The amount of flat surface is reduced to a minimum thus effecting a corresponding
reduction in the staying or bracing required (the only staying necessary being that
to the front tube plate above the tubes the furnace head between the furnace and the
shell where the man hole is placed and around the back of the combustion chamber-
The staying however must be sufficient to overcome the forward pressure produced
by the difference in area of the surface between the back and front half of such
combustion chamber taking a cross section through the centre and it will also be
necessary to fix braces between the crown of the combustion chamber and the roof of
the shell.
3° By conveying the heat around the outside of the boilers I produce an equal

page_text: expansion of all the parts and obtain an excellent circulation of the water owing to
the numerous arteries which induce circulation.
4° By my improved method of construction I have the largest body of water at
those points where the heat is greatest.
5 5° All parts of the boiler are readily accessible for examining cleaning or
repairing.
6° Owing to the fact that all the heat is utilized before leaving the boiler the
consumption of fuel is very greatly reduced.
7° The boiler can readily be rendered peculiarly adapted for liquid fuel as the
furnace can be made any length without interfering with the length of the tubes
while all the surfaces having direct contact with the fire are backed by large bodies
of water.
8° The form of my improved boiler can be varied to suit space or any other
requirement as for instance if it should be desired to construct a boiler of double
capacity and the height would be objectionable the flue or tube shell can be placed in
the middle between two furnace shells with a combustion chamber leading from each
furnace to the ends of the tubes and the steam drums can be placed between the
shells on top with proper connections and drain pipes as shewn in Figs. 4. and 7.—Or
instead of this arrangement a lower shell containing more than one furnace may be
O employed as shewn in Fig. 10. Or either form of boiler may be made with a furnace
at each end having a combustion chamber between-Or either of such boilers may be
used without a flame jacket and have the base for the chimney in the front-Or the
chimney can be placed at the front and the jacket applied at the same time by running
partitions between the boiler and the jacket so as to allow the gases and heat to pass
toward the back under the partitions and return to the front above them, as shewn
in Fig. 9.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews a view in front elevation and Fig. 2 a longitudinal section of a
horizontal boiler constructed according to my invention. In these Figures A is the
lower shell B the furnace- the upper shell containing the return tubes or flues d
e flanged nozzles or sleeves-base for chimney-g upright cylindrical shell- right
angled elbows-H man hole-I. K curvilinear plates-J combustion chamber-
L flat surface-M steam drum-o steam connections-K¹ braces-P drain pipes-
* flame jacket.
Fig. 3 shews a view in front elevation of a horizontal boiler fitted with two boilers
similar to those represented in Figs. 1. 2 and erected to be used conjointly as herein-
before described with frame jacket base for chimney and all the parts the same as for
a single boiler.
In this figure 1m are straps and m¹ eyes on straps m―The remaining letters of
reference in this Figure are similar to and indicate corresponding parts with the letters
of reference in Figs. 1. 2.
Figs. 4. 5. 6. 7. shew a horizontal compound flame jacket boiler designed specially
for light draught vessels or for any place where height may be an objection-The
boiler can be constructed on this design of very large capacity having two large
furnaces located one at each side of the return flue shell and having the circular
combustion chamber connecting both furnaces with back end of return flues and steam
drums located and connected as shewn The flame jacket may be applied or dispensed
with if desired or the boilers can be made with furnaces and return flues at both ends
with combustion chambers in the middle on the principle of what is called the double
end boiler. All the surfaces are circular requiring the least possible amount of
staying.
Fig. 4 shews a front elevation thereof-Fig. 5 a cross section taken through the
centre-Fig. 6 a longitudinal section taken on the line 1. 1. Fig. 5 and Fig. 7 is a
perspective view of the boiler complete without the flame jacket which is not shewn
in either of the Figures 4. 5. 6. 7. in order to more clearly indicate this particular

page_text: construction of boiler In these figures similar letters of reference indicate corre-
sponding parts.
A is the shell containing furnace-B the furnace-C shell containing the return
flues d―M steam drums-o steam connections between boilers and drums-H man
holes which may be located in any convenient part of the boiler-e nozzles or circulating
pipes between the shells-P drain pipes from the drums to the boilers-J combustion
chamber at rear end through which the flames from the furnace pass to enter the
return flues & the rear ends of which terminate in the tube plate which forms part of
the combustion chamber-J¹ the outer shell surrounding combustion chamber.
Fig. 8 is a view shewing the application of the flame jacket boiler to an ordinary
fire box or locomotive boiler In this figure A is the shell of boiler-B the furnace or
fire place with side broken away to shew interior-C the crown of furnace-D flues
leading from furnace to smoke box F at rear end-E steam dome-G the flame jacket
surrounding the sides and bottom of the boiler and having an outlet at the front end
over the furnace where the base for chimney H is formed-The space between the
jacket and boiler must be sufficient to allow a free draught and also to allow for cleaning
out soot and ashes and must be provided with doors at proper points for this purpose
By the attachment of the jacket the flames after passing through the tubes are
conveyed around the outside of the boiler to the stack which is placed at the front
end by this operation the heat that would otherwise pass away to the stack is first
utilized for heating those parts of the boiler which when used in the ordinary way are
condensing surfaces and by the use of the flame jacket are converted into heating
surfaces increasing the capacity of the boiler as well as preserving it by producing
an equal expansion at the same time that it greatly economises the consumption
of fuel.
Fig. 9 shews a vertical boiler having the flame jacket attached thereto In this
figure A is the shell of an ordinary upright boiler B is the furnace -C are the tubes
leading from furnace to upper head D-E is the flame jacket built around the outside
of the boiler having about 8 inches space between it and the shell of the boiler and
extending above the top of the boiler about 11 feet and being conical in form above
the top of the boiler The top of the cone at H is contracted in size to a circle corre-
sponding to the space occupied by the tubes in the top head D and on the opening
thus formed by cone there is a cover or door H hinged or otherwise fastened so that it
can be readily opened in order to clean out the tubes or for any other purpose From
the top head D on one. side of the tubes a partition F is constructed and attached
which leads up to and connects with the conical part of the jacket near the top It
then leads down obliquely on each side of the shell A and between it and the
jacket E as shewn to within a short distance of the bottom.
On one side of the cone outside of the partition is an outlet for the chimney G.
The steam drum I may be used or dispensed with as may be found convenient.
The novel feature of this application of the flame jacket is to convert an ordinary
vertical boiler into a vertical return flue boiler and to increase its capacity as a
generator by converting all the outside surface into heating surface and thereby.
produce a largely increased per centage of power at a much less expenditure of fuel
The operation of this modification of my invention is as follows. The products of
combustion pass from the grates up through the tubes of the boiler in the ordinary
way but instead of going direct into the stack from the top of the tubes the com-.
munication with the stack is cut off by means of the partition F. The combined
spaces below the end of the partition on both sides give sufficient area to ensure free
draught then, on the upper part of the jacket which extends above the boiler and
outside of the partition is formed the base and outlet to the stack so that the flames
and products of combustion after having passed up through the tubes are then led
down on one side between the outside of the boiler and the jacket and passing under
the ends of both partitions, are directed up to the stack on the other side thereby
bringing all the outside surface of the boiler in contact with the heat and by this
simple attachment converting the plain upright boiler into a return flue boiler and
giving the most economical results as regards fuel consumption..

page_text: The jacket is constructed and attached so that it can be easily and readily removed
for examining or repairing the boiler.
The following are among the many advantages that it possesses-Economy in fuel
consumption; it will occupy less space than any other boiler giving an equal amount
of power it is perfectly safe from any danger of communicating fire, even if set on
the floor of any building it is accessible for cleaning in all its parts-All the surfaces
of the boiler being brought in direct contact with heat the expansion will be equal
and consequently it is less likely to wear out or need repairs for it is completely
protected from the atmosphere.
Fig. 10 shews a horizontal boiler having two semi-circular furnaces instead of one
circular furnace-A is the outer shell-B. B furnaces-C upper shell-d return
flues chimney base-g upright cylindrical shell-J combustion chamber-
k¹ braces L flat surface-M steam drum-o steam connection-q smoke box-r flame
jacket.
I particularly wish to state that I consider the novel features of my invention are
as follows viz.
1. Combining a Cornish boiler and cylinder tubular boiler so as to produce a return
flue boiler in the different methods hereinbefore described.
2. To construct such combination boiler with a cylindrical circular combustion
chamber as described.
3. Connecting and joining the separate shells of such combination boiler together
as described.
4. The arrangement of the circulating pipes and water ways around the combustion
chamber and leading from one shell to the other as described.
5. The manner of connecting the steam drum and converting the same into a
superheater as described.
6. The flame jacket constructed and attached for the purpose of further utilizing
the hot gases and products of combustion as well as for converting the outside of the
boiler from condensing surfaces into heating surfaces and also for preserving the
boiler by preventing corrosion and unequal expansion all as described.
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. A combination boiler consisting of the combination of a Cornish boiler with a
cylinder tubular boiler so as to produce a return flue boiler substantially as herein-
before described and shewn.
2. Connecting and joining the separate shells of such combination boiler together
by flanged nozzles or sleeves and an upright cylindrical shell and otherwise all
substantially as herein before described and shewn.
3. In such combination boiler a cylindrical circular combustion chamber set at right
angles to the furnace and otherwise constructed arranged and fitted all substantially
as herein before described and shewn.
4. In such combination boiler the circulating pipes and water ways leading from
one shell to the other and around the combustion chamber constructed arranged and
fitted all substantially as herein before described and shewn.
5. In such combination boiler connecting the steam drum or steam drums in the
manner hereinbefore described and shewn and otherwise constructing arranging
and fitting the same so as to convert the same into a superheater or superheaters all
substantially as hereinbefore described and shewn.
6. In combination with a boiler the flame jacket provided with a base to serve as a
chimney and otherwise constructed arranged and fitted all substantially as hereinbefore
described and shewn.
7. The improved construction of combination boiler known as a horizontal flame
jacket compound boiler substantially as hereinbefore described and shewn at Figs. 1
and 2 of the accompanying drawings.
8. The improved construction of combination boiler being a modification of such

page_text: horizontal flame jacket compound boiler substantially as herein before described and
shewn at Fig. 3 of such drawings.
9. The improved construction of combination boiler known as a horizontal com-
pound flame jacket boiler substantially as hereinbefore described and shewn at Figs. 4.
5. 6. 7 of the drawings.
10. The improved construction of fire box boiler substantially as hereinbefore
described and shewn at Fig. 8 of the accompanying drawings.
11. The improved construction of vertical boiler substantially as hereinbefore
described and shewn at Fig. 9 of the accompanying drawings.
12. Fitting the lower shell of a combination boiler as hereinbefore described and
claimed with two or more semi circular furnaces instead of with a single circular
furnace substantially in the manner hereinbefore described and shewn at Fig. 10 of
the accompanying drawings.
Dated this 22nd day of June 1888.
ELT & Co.,
33, Southampton Buildings, Holborn, London,
Agents for the Applicant.