CERTAIN IMPROVEMENTS IN AND APPLICABLE TO BOILERS OR APPARATUS FOR GENERATING STEAM, AND IN PROVISIONAL SPECIFICATION
Year: 1853

page_text: .
LETTERS PATENT to Thomas Dunn, of Windsor Bridge Iron
Works, Pendleton, near Manchester, in the County of Lancaster,
Engineer, for the Invention of "CERTAIN IMPROVEMENTS IN AND
APPLICABLE TO BOILERS OR APPARATUS FOR GENERATING STEAM, AND IN
PROVISIONAL SPECIFICATION left by the said Thomas Dunn at
the Office of the Commissioners of Patents, with his Petition, on
the 21st April 1853.':
I, THOMAS DUNN, of Windsor Bridge Iron Works, Pendleton, near
Manchester, in the County of Lancaster, Engineer, do hereby declare
the nature of the said Invention for "CERTAIN IMPROVEMENTS IN AND
APPLICABLE TO BOILERS OR APPARATUS FOR GENERATING STEAM, AND IN
APPARATUS CONNECTED THEREWITH," to be as follows:-
Firstly, in a mode of staying or strengthening boilers which may be
already made, & of defective form, or which may be deemed unsafe,
by stays or strengthening parts so arranged and constructed that they
shall form "flues," when placed in water spaces; and form "water

page_text: spaces," when they are placed in flues; and thus add increased heating
surfaces with increased strength; and which are also so arranged and
adopted that, in case the water should get too low, they will blow off,
and so prevent explosion from the parts exposed to the heat of the
furnace getting too hot.
Secondly, in constructing the inner "fire box" of boilers, of such
form that-they have more heating surface than is usual, & thereby
giving increased strength, the inner parts of which boilers are rendered
easy of access, by reason of thus dispensing with the greater portion of
the usual internal stays.
Thirdly, in combining together a series of cylindrical vessels or
cylinders, of generally small diameter, which I propose to form or con-
struct of thin plates of metal rivetted or otherwise secured together, (of
a thickness proportionate to their diameters), and to arrange them in such
manner that the current of smoke and gases from the coal or fuel and
the atmospheric air shall mix and blend together, and ignite, and thus,
as far as possible, prevent the smoke nuisance; and also in arranging the
cylindrical vessels or cylinders in such manner that some of them which
will only contain steam generated by the other cylinders or cylindrical
vessels shall be exposed to the heat, and to the heated products from
combustion of the fuel; and which arrangements of cylinders or cylin-
drical vessels I propose to combine with walls or brickwork, or other-
wise, and to place & connect them in such manner that those which
may become worn by the intensity of the heat to which they are
exposed may be turned or changed to places less exposed, or that they
may be replaced with new ones. This description of boiler will be, from
the number and lightness of its parts, portable and easy of transport.
Fourthly, in forming, constructing, and arranging of boilers for
sea going vessels, or for other purposes, so that portions of such
boilers which may become defective may be removed to be retubed or
otherwise repaired, without greatly interrupting the working of the
remaining parts of the apparatus or boilers.
Fiftly and lastly, in the peculiar construction and mode of fixing a
fusion or anti-explosion plug, for the purpose of preventing injury to
the boilers when there is a deficient supply of water."
:
. . C.

page_text: ADDITIONS TO THE PROVISIONAL SPECIFICATION..
Firstly, the stays or strengthening parts herein referred to are made
hollow, of plates of iron rivetted or welded together, and are made to
connect those parts intended to be stayed; and in case the stay passes
through a water space, the heat is made to pass through it; but, should
the stay pass through a flue space, & connect water spaces, it is filled
with water, which is exposed to the heat of the flue. The arrangement
for preventing explosion is effected by the insertion, in the most exposed
parts, of fusion plugs," which fuse or melt when the temperature
exceeds certain limits fixed upon.
Fourthly, consists in making such boilers or steam generating appa-
ratus, of a series of parts containing tubes or otherwise, which parts
are repetitions of each other in form and dimensions, so that a defective
part can be readily removed and replaced by a duplicate, or so that the
defective part may be removed, the remaining parts continuing in
operation.
Fiftly & lastly, it consists in forming the plug of two parts or metals,
of a core of metal which will not readily fuse or melt, covered or coated
with a crust of metal which will fuse or melt at the given temperature;
the core of the plug being formed of such size that its larger end will
pass through the orifice in which it is inserted when freed from the
external crust or fusion metal. It is fixed by insertion in a conical
orifice, and is intended to keep the orifice tight, so as not to allow any
escape, till the whole of the external or fusion metal is melted away,
when it will leave the orifice entirely.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Thomas Dunn, in the Great Seal Patent Office;
on the 21st October 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THONAS DUNN, of Windsor Bridge Iron Works, Pendleton,.. near
Manchester, in the County of Lancaster, Engineer, send greeting..

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Ier
.Letters Patent, bearing date the Twenty-first day of April, in the year
of our Lord One thousand eight hundred and fifty-three, in the sixteenth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas Dunn, Her especial licence that I, the
said Thomas Dunn, my executors, administrators, and assigns, or
such others as I, the said Thomas Dunn, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "CERTAIN IMPROVEMENTS IN AND
APPLICABLE TO BOILERS OR APPARATUS FOR GENERATING STEAM, AND IN APPA-
RATUS CONNECTED THEREWITH," upon condition, amongst others, that I,
the said Thomas Dunn, by an instrument in writing under my hand
and seal, and should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
'
NOW KNOW YE, that I, the said Thomas Dunn, do hereby declare
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement (that is to say):
The first part of my Invention relates to a mode of strengthening
boilers of that class which are not well calculated to resist pressure,
and by which mode of strengthening such boilers the surface exposed
to the heat from the surface is increased. For the purpose of explain-
ing this part of my Invention, I refer to the drawings annexed hereto,
the Figures of which, before proceeding further, I will enumerate and
explain. Sheet 1, Fig 1, cross or end sectional view of a "waggon
boiler," shewing brickwork and flues; Fig. 2, sectional plan of the
same; Fig. 3, end sectional view, shewing fire box of a tubular
boiler; Fig. 4, plan sectional view, and Fig. 5, side sectional elevation
of the same Fig. 6, sectional elevation of an upright boiler; Fig. 7,

page_text: plan sectional view of the same; Fig. 8, sectional elevation of another
upright boiler; Fig. 9, plan sectional view of the same; Fig. 10, sec-
tional elevation, shewing mode of applying improved fusion plug;
Fig. 11, plan of the same; Fig. 114, sectional front view of combfire
bridge; Fig. 12, sectional longitudinal view, shewing multi-cylindrical
boiler; Fig. 13, end or cross sectional view of the same; Fig. 14, lon-
gitudinal sectional view, shewing tubular cylindrical boiler; Fig. 15,
end or cross sectional view of the same; Fig. 16. sectional view of a
cylinder detached.
The Figures 1, 2, 6, and 7, will explain the first part of my
Invention. Figs. 1, and 2, exhibit a boiler of common and well
known form, which has hitherto been stayed or strengthened by the
tie rods between those points, which, from its form, were liable to be
forced outwards by internal pressure. This part of my Invention con-
sists in placing a number of cylindrical stays from one side to the other
side of such boilers, connecting those parts which are concave exter-
nally, and in arranging the flue to pass from the furnace under the
boiler, and then thread through each of the cylindrical stays to the
chimney, which will thus form flues, and thereby add increased heating
surface to this form of boiler. The bottom of the boiler is stayed by
rods passing between the bottom and top of the boiler as usual, and by
the introduction of "gusset" or angle stays rivetted or bolted to the
sides, leaving corners cut out at the lowest points as a channel for.
sediment, and for washing or cleaning out. The parts marked a, in the
drawings, represent the shell or external parts of the boilers; b, the
cross cylindrical stays or flues; c, perpendicular tie rod; d, gusset or
angle stays; d, the channel in the gusset or angle stays, which has.
been referred to. A, is the brickwork supporting the boiler, and form-
ing external flue; A', brick partitions, to cause the draft to pass
through the cylindrical stays, as pointed by the arrows; B, being the
flue passage, and B', the point where it leaves for the chimney. e, is
the water line; a', the man hole; f. fire doors; g, the furnace or grate
bars.
.
Figs. 6, and 7, shew the mode in which I strengthen and add in-
creased heating surface to upright boilers of the form shewn; that is,
having cylindrical fire or furnace boxes. It is by the same means, as

page_text: already explained with respect to "waggon" boilers, with the excep
tion that the cylindrical stays employed are of smaller proportionate
diameter, and; instead of forming flues and tie stays, they will form
water spaces and thrust stays. I prefer that they should be placed in
pairs, crossing each other at right angles. I also prefer to construct
the larger cylindrical stays of iron boiler plate rivetted together, and
secured to the sides by angle flanges, formed on the ends by rivetting or
otherwise; for upright boilers, welded tubes may be used. In Figures 6,
and 7,, is the shell; h, the sides of the fire box; b, the cylindrical
stays; B, flue passage to the chimney; f, furnace door; y, grate or
furnace bars.
and top of
The front
The second part of my Invention relates to the mode of con-
structing the inner fire boxes of tubular and other boilers; this con-
sists in corrugating the flat sides, continuing the corrugations from
one side over the top and down the other side, the flat sides of the
outer shell being stayed by T iron (a), rivetted to the sides; when this
construction and arrangenient is adopted the fire box can (with less
labour than those as generally constructed) be readily withdrawn for
repair, when separated from the shell of the boiler (at the front) and
the tubes, the T iron rivetted on the shell being made clear of the
corrugations. Instead of T iron (a) being employed to stay the out-
side shell, it may be stayed by bolts (a³) in the usual manner. Fig. 3, 4,
and 5: a, is the shell, or outside of the boiler; h, the sides
the corrugated fire box; i, the tube plate; j, the tubes.
end of the boiler is stayed in the ordinary manner by tie bolts, as
the front end, when thus constructed, will withdraw with the fire box
when repairs are required. The Figures above mentioned shew both
the methods alluded to for staying the outside, or shell, on one side
of the fire box, by the Tirons a, rivetted to the sides, and on the
other side by the usual tie bolts a³. As the corrugations are con-
tinued over the top of the fire box, as seen in Fig. 3, and 5, the usual
beam stays are dispensed with. This part of my Invention is shewn as
applied to upright boilers in Figs. 8, and 9; the corrugations are, by
this mode, continued round, forming a corrugated cylinder. The cor-
rugated parts may be made either of plate or cast iron; but for
economy, in-small upright boilers, I prefer them of cast iron.

page_text: The third part of my Invention relates to the construction and arrange-
ment of boilers or apparatus for generating steam, to be obtained from a
combination of a series of cylinders of generally small diameter, which
I propose to make of such length and diameter as to render them
portable, and convenient of transport, and to form them precisely
duplicates of each other, by which provision I can readily replace or
renew them, take away from them to diminish, or add to them to
increase, the generating power. I also make provision by which the
sides exposed to the action of the furnace may be changed, by making
the branches and flanges of the pipes connecting with the feed water
and steam reservoir duplicates of each other; and to facilitate the
removal or disconnection of any one or more of them without disturb-
ing the others, or the brickwork supporting them, they are placed in
iron frames supported upon brick or other walls. From the small
diameter of the cylinders they may be constructed of thin plates, by
which their lightness will be secured, and the ends may be made of
cast iron of the hemispherical form, provided with short branch pipes
(a) (already alluded to), on opposite sides having flanges, and with.
an external flange for one end, and with a socket flange for the other
end of the cylinder, for the purpose of revitting them to the end of the
cylinders; or both ends may be formed with socket flanges, faced to
fit the ends of the cylinders, and secured to them by a bolt (a).
passing from end to end, through the centre of the cylinder, as shewn
detached at Fig. 16.
I have now to describe the manner of combining the cylinders
together, which is shewn in. Fig. 12, and 13. a, are the cylinders
placed side by side, within a few inches of each other; they are
supported at the ends by an iron fraine k, as before mentioned,
which rests upon the side walls. This iron frame forms a saddle to
each, by which means the adjoining cylinders, or the brickwork, is
kept undisturbed by the removal and replacing of one or more of the
cylinders. Between each cylinder a column or arm ¹, is carried up
from the frame or saddle, upon which are carried beams 1, for support-
ing the steam reservoirs cylinders a*, (which are shewn placed longi-
tudinally across the top of the lower cylinders,) and also for the purpose:

page_text: of supporting the covering of the boiler. The steam reservoir is formed
by uniting two of the duplicate cylinders by their flanges, end to end;
using as many cylinders as are necessary for the steam room required.
It will also be seen, by reference to the drawings, that there are two
ranges of pipes m, and n, which pass alongside one end of the cylinders,
one range being a little above and the other a little below themi, to
which they are connected by angle or elbow pipes, m, n, being thus
arranged, that the cylinders may be withdrawn from their places, with-
out disturbing the main pipes. The elbows m, n, being removeable
from the short branch at the end of the cylinders, give also facility for
uniting any two or more cylinders together, end to end. Another range
of pipes may be employed at the other ends of the cylinders, if thought
desirable, for the passage of the steam to the reservoir cylinders as shewn,
upon either of which as many safety valves (0) may be fixed as may
be deemed requisite. The bridge of the furnaces is formed by a
cylinder a, g, through which, I prefer, should pass the water for feeding
all the other cylinders, by means of the lower range of pipes m, which
are connected with the bridge cylinders a, g, which will remain full of
water; the other cylinders (with the exception of the reservoir cylinders)
which are not supplied with water being maintained at about the
water line e. By the arrangement shown in the drawings, it will be
seen that two furnaces are used, one on each side, leaving the division
walls A', to form a flue between the furnaces which meet at the ends, so
that the gas flame and smoke may mix and ignite, and then pass along
the middle flue towards the front or furnace end, where arriving, it may
As the cylinders are not close
pass by a down flue to the chimney.
together, a stopping D, is inserted between them, so that the intense
heat from the furnaces will be confined to the lower parts of the
cylinders. To prevent the heat from passing out at the top, a covering
of brick work or other material E, is used, supported by the beams ;
while radiation from the steam cylinders may be prevented to a great
extent, by a covering of felt E', as commonly employed for such pur-
poses.
Instead of the flue passing to the chimney from the point
mentioned, it may be returned so as to pass over all the lower cylinders,
and under that portion of the steam cylinders (a*) which are exposed
°

page_text: to it, back to the end furthest from the furnace, and from thence to the
chimney. It will be obvious that another series of cylinders may be
conveniently joined to the ends of the first, and that other cylinders may be
added at the sides to any convenient extent, where additional generating
power is required. By the arrangement of the furnaces and flues in
this part of my Invention as described, it is intended that they shall be
fired alternately, so that the smoke may be consumed as far as practicable:
but for the purpose of assisting to produce this effect more perfectly, I
propose (in place of the hollow water fire bridge a, g,) to carry the fire
bridge within a few inches of the bottom of the boiler, the bridge being
formed to the shape of the bottom of the boiler, and with a number of slits
through it, which will give to it in front the appearance of a comb. It may
be formed of brick or other suitable material which can be heated to a red
heat; the object of the arrangement being, that the bridge, when heated
red hot by the incandescent state of the fuel, may ignite and inflame
the smoke or gases (produced from every fresh supply of coal feed into
the furnace) as it passes through the slits made in the bridge. This ex-
planation is illustrated in Fig. 1; », being the fire bridge, and s, the slits.
Hot or cold air may be admitted at the front or back of the bridge, by
any of the usual methods, and within the bridge, by forming it of iron,
making the base part hollow, and providing it with holes between the
slits or teeth of the bridge; or air may be admitted at the sides of the
teeth as well as at the bottom of the slits, if the teeth be made hollow;
and provided with holes in the sides; or for convenience, the lower part
or base of the bridge may be formed hollow, with holes to admit are
between the teeth, and have sockets formed in it, to receive and
retain upright and in their places the teeth of the bridge, (which may
be of brick, or any other suitable material having the character already
mentioned,) by which arrangement the toothed parts may be renewed
at little expense when burnt away. This is shewn in the drawings, at
Fig. 11, which is a sectional view of the bridge; r, being the base
part of iron; t, the teeth inserted in the sockets t'; u, holes for admis-
sion of air. It is obvious that the description of bridge herein de-
scribed inay be adapted to any class of boilers having bridges. In
respect of the arrangement of boilers shewn, and described in this

page_text: part of my Invention, I do not confine myself to it, as it may be
variously modified, and still retain the peculiar advantages set forth;
the cylinders may be combined with one furnace only, and the flues may
be arranged differently.
The fourth part of my Invention relates to the forming, construct-
ing, and arranging of boilers, for marine or other purposes, the object
of which is, to give facility for the removal and replacing of portions
of such boilers as may become defective, without greatly interrupting
the working of the remainder of the parts. I carry out the principle
already explained in the third part of my. Invention, as far as regards
the precise duplication of the parts to be formed into a boiler, or
steam generating apparatus, and also the arrangement for the pur-
pose of effecting a connection or disconnection without disturbing
the communicating pipes or other adjoining parts. The parts here re-
ferred to are formed of any convenient diameter and length, with tubes
or flues passing from end to end; these parts are arranged side by
šide, the flue being made to pass under, and then through the tubes or
flues of each individual part. Figures 14, and 15, in the drawings, shew
this part of my Invention: the tubular portions are shewn as supported
on brick work at their ends, which forms a flue, by which their ends
are connected; brick partitions being placed in the flue, by which the
draft is directed through each of the tubular portions in succession, until
it has passed through the last, which, in this arrangement, is that
directly over the furnace. The spaces between the parts are stopped
by a layer of bricks D, so as to prevent the heat ascending between
them. When any part requires detaching, it is to be lifted perpen-
dicular from the brick seating, and replaced by another duplicate of it.
To further facilitate the removal of parts, a valve should be placed at
each junction of the main steam and water pipe with each of the por-
tions, so that the communication between each part and the others can
be cut off by the valves, which will enable the parts to be connected and
disconnected without greatly interrupting the working of the other
parts. For marine purposes, instead of brick work, a framing of
rivetted plate work may be formed, corresponding to the brick work
shewn in the drawings, having water spaces in the parts exposed to the

page_text: heat; the sides being stayed by tie stays, in the usual manner of stay-
ing fire boxes, and which may be in communication with the water and
steam, and of the other removeable parts of the boiler. The flue in the
side framing may pass from end to end, along the ends of the parts; and
the stoppings for diverting the draft through each successive portion
may be formed of brick work; the crevices between the iron work. may
be stopped by a plaster of fire clay, or other plastic materials.
The fifth and last part of my Invention relates to the construction
and mode of fixing a "fusion plug," for the purpose of. préventing injury
to boilers by explosion, when there is a deficient supply of water. This
is shewn in Figs. 10, and 11. It consists in forming the plug of two
metals, namely, of a core of metal, similar in form to P, which will not
readily fuse or melt, (such as iron,) and of a covering or cruist of metal
P', which will fuse or melt at the given temperature, which may be the
metal commonly used for fusion plugs: this plug is inserted in a conical
orifice 9, (as.shewn,) the lower part of the orifice being large enough to
admit the largest part of the "core" to pass through it when all the
fusion metal is melted away. The object of this arrangement and con-
struction of plug is that of keeping the orifice tight, so as to prevent any
escape till the whole of the fusion metal is melted away, when it will leave
the orifice entirely. I have not considered it necessary to name every part
in the Figures described, as I have proceeded; but as the same letters
and figures denote in each figure the same or similar parts, those parts
will be readily known by the letters or figures upon them.
<
Having now particularly described the nature of my Invention, and
the manner in which the same is to be performed and carried into
effect, I wish it to be understood, that I do not claim all the parts herein
referred to, and described as my Invention, nor do I confine myself
to the precise details. But what I claim is, the mode of strengthening
waggon" and upright boilers, as described in the first part of my
Invention; the mode of forming the fire boxes of tubular or other boilers,
as described in the second part of my Invention; the mode of forming
steam generating apparatus, the novelty of which consist principally in
the precise duplication of the parts, by which certain objects and advan-
tages are obtained, as enumerated and described, and also in the mode

page_text: of forming and constructing the fire bridges of boilers with slits, for the
purpose of promoting the consumption of smoke, as explained in the
third part of my Invention; the mode of constructing and arranging
boilers or steam generating apparatus, for the purposes described in the
fourth part of my Invention; and lastly, the mode of constructing and
fixing a fusion plug, as described in the fifth part of Invention.
In witness whereof, I, the said Thomas Dunn, have hereunto set
my hand and scal, this Nineteenth day of October, One thou-
sand eight hundred and fifty-three.
Signed, sealed and delivered
(being duly stamped, by
the within-named Thomas
Dunn, in the presence of
THOMAS DUNN. (L.S.)
PETER J. LIVSEY, of Manchester.