METHOD OF CONSUMING SMOKE IN STEAM ENGINE OR OTHER FURNACES OR FIRE- PLACES
Year: 1855

page_text: METHOD OF CONSUMING SMOKE IN STEAM ENGINE OR OTHER FURNACES OR FIRE-
PLACES."
PROVISIONAL SPECIFICATION left by the said Alexander M'Dougall at
the Office of the Commissioners of Patents, with his Petition, on the
29th March 1855.
I, ALEXANDER MCDOUGALL, of Manchester, in the County of Lancaster,
Manufacturing Chemist, do hereby declare the nature of my said Invention
for AN IMPROVED METHOD OF CONSUMING SMOKE IN STEAM ENGINE OR OTHER
FURNACES OR FIRE-PLACES" to be as follows:-
My improved method of consuming smoke in steam engine or other furnaces
or fire-places consists in so arranging two. furnaces or fire-places as to cause
the unconsumed products of combustion or smoke arising from one fire which
has just been replenished with fuel (and which I call the green fire) to pass
over another fire or furnace from which the superabundant smoke has departed,
and is consequently burning brightly. This is effected by means of suitable
dampers and flues, and also by alternately "firing up." These dampers are so
arranged, that upon one furnace being replenished its damper will be closed,
and the damper of the other furnace opened, thus causing the draft, and
carrying the smoke to be burned or consumed through the connecting flues
between the two furnaces and over the second or bright fire, and from thence

page_text: through the open damper up the chimney, or again under the boiler, and
vice versá; thus each furnace becomes alternately the producer and consumer
of the smoke evolved from the coal.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexander McDougall, in the Great Seal Patent Office on
the 29th September 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MCDOUGALL, of Manchester, in the County of Lancaster, Manufacturing
Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-ninth day of March, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Alexander McDougall, Her especial license that I, the said Alexander
McDougall, my executors, administrators, and assigns, or such others as I, the
said Alexander McDougall, 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 "AN
IMPROVED METHOD OF CONSUMING SMOKE IN STEAM ENGINE OR OTHER FURNACES OR
FIRE-PLACES," upon the condition (amongst others) that I, the said Alexander
McDougall, by an instrument in writing under my hand and seal, should par-
ticularly 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 Alexander McDougall, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement and accompanying Drawings (that is to say) :-
:-
My improved method of consuming smoke in steam engine or other furnaces
or fire-places consists in so arranging two furnaces or fire-places (that is within
the boilers) as to cause the unconsumed products of combustion or the smoke
arising from one fire which just been replenished with fuel, and which I
call the "green fire," to pass over another fire or furnace from which the
superabundant smoke has departed, and is consequently burning brightly. This

page_text: is effected by means of suitable dampers and flues, and also by alternately
firing up." These dampers are so arranged, that upon one furnace being
replenished its damper will be closed, and the damper of the other furnace
opened, thus causing the draught, and carrying the smoke to be burned or con-
sumed through the connecting flue between the two furnaces and over the
second or bright fire, and from thence through the open damper up the chimney,
or again under the boiler, and vice versa; thus each furnace becomes alternately
the producer and consumer of the smoke evolved from the coal.
In order that this Invention may be better understood and explained in
detail, I have hereunto attached a Sheet of Drawing made to a scale of about
half an inch to the foot, and having marked similar letters of reference upon
corresponding parts of the apparatus in all the Figures.
Fig. 1 represents a front elevation of a steam boiler having two furnaces or
fire-places within the boiler, and likewise shews an arrangement by which the
dampers may be alternately and simultaneously elevated and depressed; Fig. 2
exhibits a longitudinal sectional elevation, taken vertically through the centre.
of one of the furnaces or fire-places of Fig. 1; Fig. 3 is a transverse sectional
elevation, taken in the direction of the dotted line A, B, (Fig. 2); Fig. 4
represents a longitudinal section, taken horizontally on the dotted line C, D,
(Fig. 1.)
This Invention will be most readily observed by referring in the first place
to Fig. 4, where it will be remarked that the furnace or fire-place a is repre-
sented as having been just replenished with fuel (the damper & of the furnace
or fire-place a being closed), and the consequent generation of dense smoke or
unconsumed products of combustion is taking place. The fuel of the furnace
or fire-place having burnt brightly, the bed of the furnace 6 will present a
"live fire," over which the smoke generated in the furnace a is compelled to
pass, (a free channel for the circulation of the smoke between the furnaces
being always open through the connecting flue m at the end of the boiler,) and
in which passage the products of imperfect combustion forming the smoke and
generated at the "green fire" in the furnace a is effectually consumed. This
is effected by raising the damper d, and closing the flue c of the furnace a at
the time of "firing up the furnace a), and simultaneously lowering the
damper e and opening the flue f of the furnace b, thus reversing the draught
from the main flue g, and checking all egress for the unconsumed products of
combustion from.the "green fire" in the furnace a, except by the flue f, and
immediately over and in contact with the bright and live fire in the furnace b,
by which means the unconsumed products of combustion are rendered ser-
viceable, a greater volume of heat obtained with perfect consumption of smoke,
"

page_text: and consequent reduction of fuel employed. By the time that the fuel in the
furnace a has attained a white heat, and perfect combustion is maintained, the
fuel in the furnace b will have burnt down and exhausted itself, consequently
requiring "firing up" or replenishing with fuel. The dampers d and e must now
be respectively elevated and depressed, thus opening the flue c of the furnace a
and closing the fluef of the furnace 6. The current of the draught will now
be reversed, and the superabundant smoke from the "green fire" in the furnace
b will be carried in the direction of the arrows over the now "live fire" in the
furnace a; where a perfect consuming of the smoke will take place, and the
caloric continue its course through the flue c to the main flue g; thus it will be
seen that by alternately closing and opening the flues c and ƒ at the time of
firing up," an effective combustion of the smoke evolved from either furnace
is attained. The dampers e and d are formed of a case or box of cast iron, open
at one side and filled with fire brick, so that the face of the fire brick may
always be presented to the flue. 'The dampers are actuated by the handle h
in front of the boiler, the cross beam j, arcs k, k, and chains 7, 1, secured to the
top of the iron case of the damper (see Figs. 1 and 3). For the purpose of
keeping the fire doors cool, I propose to make the "dead plate" hollow, and to
feed the boiler with water through the "dead plate."
Having now particularly described the nature of this Invention, and the
manner in which the same may be performed, I wish it to be distinctly under-
stood that I claim the novel and particular arrangement of flues and dampers
to furnaces or fire-places where two or more are used in conjunction with each
other, so that the draught may be reversed at will, in such a manner that the
superabundant smoke of one furnace or fire-place may be made to pass over
and in contact with the bright fire of the other for the purpose of ensuring its
effectual consumption, as herein particularly described and set forth, and fully
illustrated in the accompanying Drawing.
In witness whereof, I, the said Alexander McDougall, have hereunto set
my hand and seal, this Twenty-eighth day of September, in the year
of our Lord One thousand eight hundred and fifty-five.
A. MCDOUGALL. (L.S.)